Individual Operations Management Report Essay Example | Topics and Well Written Essays - 1000 words

Individual Operations Management Report - Essay Example After conducting an analysis using Statistical process control tools, the company found that there processes are out of control and they are not meeting the quality standards. Table of Contents Introduction & Problem Description: 3 Methodology: 3 Results: 4 Types of Data: 4 3 Sigma control for the processes: 4 Discussion and recommendations: 7 Conclusion: 8 Bibliography: 9 Appendix: 10 Introduction & Problem Description: RTP Industries is one of the most renowned manufacturers of steel and aluminum products. The company holds its footstep in the major countries of the world and operates globally. Due to stiff competition in the recent years from Chinese and Indian manufacturers, the company has lost a significant portion of its market share. To reestablish itself, the company is emphasizing on research and development program in order to innovate new products. Quality has remained the top priority since then as the company expects that through quality assurance and control it can aga in boost its sales. Total Quality management has been at the heart of company’s vision and it has been introducing tools and techniques to maintain the quality of its products. One of the tools it has recently deployed is Statistical Process Control for measuring the performance of the manufacturing process and to let identify it there are any weaknesses in the process. Recently, the company has received a lot of complaints regarding the hydraulic products. It was believed that the discrepancies in the size and surface quality of the steel rods are causing leakages in hydraulic products. Methodology: In order to meet the required standards and improve its quality, the quality manager has planned to run a Statistical Process Control Analysis. A Statistical process control involves a random sampling of the output of the process which determines whether the process is meeting the quality standards or not. For the above purpose, the quality manager has randomly collected data on samples of three steel rods daily. The quality manager collected two types of data The diameter of the selected steel rods was measured and recorded in centimeters over a 25 day period. The number of surface errors in the selected steel rods was calculated and recorded over a 25 day period. Results: Types of Data: There are two different types of data given to us in this scenario. The first data is concerned with the diameters of the selected steel rods. As we know that diameter is a continuous variables and it can take any value therefore we will use an x chart as a Statistical process control chart to monitor the process. The second set of data contains information about the number of surface errors in the selected steel rods. The second type of data has used sampling through attributes measure for the collection purpose. Since it contains information about whether there are surface errors in the steel rod therefore it is measuring the attributes of the steel rods. We will use a c chart as a Statistical Process Control tool for monitoring this process since there are more than one surface errors in some steel rods so we will count number of errors per steel rod. 3 Sigma control for the processes: Size of diameters of rods: For the first sample of data regarding the diameter of the

Classical to the Post-Modern Eras Essay Example for Free

Classical to the Post-Modern Eras Essay In this essay, I’m going to trace the development of Classical Music from the late 1750s to the Post-Modern era in the 2000s and provide a brief history of music, and how they link together to form what we have today. There are many preconceptions of what the history of music is. Some people think it is mainly a biography of composer’s lives, but they are wrong. The history of music is primarily the history of musical style. In order to appreciate this, it is essential to become acquainted with the different sounds and to hear them in their contexts. Fashions in history change with the generations, like fashions in musical tastes. Lets first start with the classical music, Classical is an era; it is from about 1730 to just after 1800. A few people who contributed to the music in the Classical era are: Ludwig van Beethoven, Joseph Haydn and Wolfgang Amadeus Mozart. The Classical period focused on the opposite types of sounds- music during that period was orderly, uncluttered, well planned and precise. Music was expected to be technically pleasing and grounded in certain traditions and styles that had been approved by the public, often quite formal. Composers were seen as workers who were hired to write music that would please their employer (Sagebiel). The classical period of music combined harmony, melody, rhythm, and orchestration more effectively than earlier periods of music. The classical period is best known for the symphony, a form of a large orchestral ensemble. The symphonic pieces generally had three movements, the sonata, the minuet and the finale. Building of the achievements of earlier composers, Haydn, and Mozart brought the symphony to its peak in the last twenty years of the 18th century. Haydn excelled in rhythmic drive and development of theme-based music (Bishop 325). Mozart also added to the symphony by contrasting memorable lyric themes in full sounding orchestral settings. There are many styles of music within classical music, including symphony, opera, choral works, chamber music, Gregorian chant, the madrigal, and the Mass. A Classical composition will fluctuate in mood. Not only there are contrasting themes within a movement, but there also may be striking contrasts even within (Vardy). In Classical music, there is a flexibility of rhythm. A classical composition has a wealth of rhythmic patterns. Classical music is basically homophonic. However, texture is treated as flexibly as rhythm. Classical melodies are among the most tuneful and easy to remember. The Classical composers interest in expressing shades of emotion led to the widespread use of gradual dynamic change crescendo (gradually getting louder) and diminuendo ( gradually getting softer). By varying the finger pressure on the keys, a pianist can play more loudly or softly. Classical works show a great deal of musical sophistication and use development, key changes, variation, musical phrases of varying lengths, counterpoint, polyphony and advanced harmony development. It uses very specific instruments, most markedly those invented before mid-10th century and adopted in the 18th and 19th centuries, such as instruments like violin, cello, viola, woodwind instruments, brass instruments and other instruments in the orchestra and solo instruments such as piano, harpsichord, organ and guitar. The classical period had a musical style that was consistent, which means that if you were a composer in this time period; you knew what was expected of you. Haydn had a huge influence on the development if Classical music and so did Beethoven but he chose to focus on a more romantic style which had a simple chord structure. This brings us to the Romantic era; The Romantic music period began in 1825 and ran until 1900. Several historical themes were at work during this period, including the increasing role of science as a worldview, the rise of nationalism in Europe, and a growing appreciation for the arts. The style of the Romantic music period is generally characterized by a wider range of dynamics, a greater variety of instruments, more dramatic melodies, more extreme tempos, fuller harmonies, and expanded formal structures within the compositions. Some of the most famous composers of all time lived and worked during the Romantic music era. Schubert, Chopin, Wagner, Brahms, and Mahler are among the most recognizable names. The transition from nineteenth-century Romanticism to twentieth-century Modernism is perhaps one of the big points in music history. Because the speed of twentieth-century innovation in all areas has been so accelerated, music has also moved from one new idea to another with such speed that no previous era can be compared to. Technology and scientific discovery are probably the basic influences on musical creativity and production. Dissonance became very important and in fact most of the pieces are made up of dissonant chords (Palisca). During the Modern era, many new musical techniques emerged. They were seen in melody , harmony , rhythm, meter, texture, tonality, and sonority . It is important to note that during the twentieth century not all changes in music were a revolution or a return to old ideals. Contrapuntal textures in music dominate the Modern era. While, homophonic textures are present, it is to a lesser degree and with less importance. During the 20th century, tone color has become a more important element of music then it was ever before. It has a major role which is creating variety, continuity and mood. Consonance is no longer in use in the 20th century. 20th century music sound fantasy like, distant and mystifying. Chords are never as fundamental as it is in previous centuries. Poly chords are created by placing one traditional chord over another. The rhythmic vocabulary of the 20th century was expanded with increased emphasis on irregularity and unpredictability. The Melody was very elusive.

EEG-Based Processing Approach for Pain Detection

EEG-Based Processing Approach for Pain Detection Abstract-To detect the pain based on EEG signals variability, several efforts has been made but no promising result has been achieved yet. In this study, we propose different features to classify pan. EEG signals of 28 healthy volunteers were recorded continuously while they experience pain through the known ice-water paradigm. To access the de-correlated EEG sources, Independent Component Analysis(ICA) scheme was used. Among them, the artifact and noise sources were removed and therefore pain dependent sources were determined and projected back. Before the classification, some features were extracted from the EEG signal. To select the best features, sequential forward selection (SFS) was applied which also eliminates the redundancy. The classification results provide 89% , 90% and 94% accuracy when one nearest neighbor (1NN), 3NN and support vector machine (SVM) were used, respectively. Keywords: EEG sources, pain dependent features, entropy, feature selection. Introduction Backonja et al. [1] proposed an ice-water bath as a gradual painful stimulus, termed as the cold presser test (CPT). in this study, CPT is applied as the pain inducing paradigm. Some studies, inveatigated the changes during pain. The result of some previous studies[2-5] was reported as an increase in the Delta and Beta bands and a decrease in the Alpha band during pain. In another study, a tonic pain stimulus [6] increased the power of Delta, Beta-III and Gamma bands and decreased the Theta, Alpha-I and Alpha-II band powers. Intramuscular injection of hypertonic saline increases the Beta power[7]. In another research, inducing Capsaicin caused no significant change in the EEG bands. Another study implied changes of Alpha band activities interact in pain-perception process [8]. In another research, two levels of pain were classified by NaÃÆ' ¯ve Bayes classifier which produces 86.3 ±8.4% classification accuracy [21]. In a different approach, fMRI images of the participants brain were observed while they were experiencing pain by heat induction which resulted in 94% accuracy [9]. The most repeated findings of these studies is a general increase in the power of Beta band simultaneous to a decrease in the Alpha band with a possible coherence increases across different bands, as the brain response to pain. In Section 2, the data recording and the preprocessing are explained; In Section 3, the methods are described in detail; in Section 4, the results are presented. Section 5 concludes the results. Data Recording and Preprocessing 2.1. Data Recording For recording EEG signals, 30 electrodes were used by Scanlt EEG recording system. A cap based on 10-20 electrode placement system was used for recording. The impedance of all electrodes was less than 5 kilo ohms. The sampling rate was adjusted at 250 hertz and a bandpass filter with cut-off frequencies adjusted in 0.5 and 47 hertz was implemented to the signal. In previous studies, laser, cuff pressure, hot/ice water, Electrocutaneous stimulation [10]-[13], have been used to induce pain. In this study, the ice-water (also called CPT) was selected to have minimum side-effect. The recording procedure took place in a quiet room. First, to achieve a baseline recording for each volunteer, a 30 second EEG signal were recorded in the resting position, which is called no-pain class. Then, by putting their hand in the cold water (1.7 ±0.2centigrad) after a while, they reported the pain. The recording continues till the tolerating time for each subject. With respect to the fact of artifacts presence in the EEG signals and to record the noises with higher quality, some electrodes on the face muscles were put to detect EMG artifacts. Also, EOG is one of the other artifact sources in EEG. 2.2. EEG Artifacts Eliminating Principal component analysis (PCA) and regression methods[14] are the methods used for eliminating the EEG artifacts such as muscle artifacts and eye artifacts. Also ICA has been introduced more effective for decomposing the recorded signals into uncorrelated sources [14] which is applied here to remove the EEG artifacts. 2.2.1. Independent Component Analysis (ICA) The components x i {displaystyle x_{i}} of the observed random vector x = ( x 1 , à ¢Ã¢â€š ¬Ã‚ ¦ , x m ) T {displaystyle x=(x_{1},ldots ,x_{m})^{T}} are generated as a sum of the independent components s k {displaystyle s_{k}} x i = a i , 1 s 1 + à ¢Ã¢â‚¬ ¹Ã‚ ¯ + a i , k s k + à ¢Ã¢â‚¬ ¹Ã‚ ¯ + a i , n s n {displaystyle x_{i}=a_{i,1}s_{1}+cdots +a_{i,k}s_{k}+cdots +a_{i,n}s_{n}} weighted by the mixing weights a i , k {displaystyle a_{i,k}} [15]: X= AS (1) Where S is sources vector, X is the recorded signals (EEGs) matrix. To calculate its inverse or pseudo-inverse, termed as W, the equation(3) is used: S =WX, where W=A-1 (2) 2.2.2. EOG Artifact To remove the most important EEG artifacts, which are EOG and EMG artifacts, the similar process was done. As the Fp1 channel is the most contained EEG channel, the correlation of this channel with all determined sources, was calculated Eq.4 is the correlation formula. If the value exceeded 0.7, the corresponding source was selected as the suspicious EOG source[16]. (3) Where Ri is the correlation of the ith source with the recorded signal at Fp1. Fig.1 shows the spectral map of the determined EOG source which is mostly on foreahed space. Shanon Entropy (4) Fractal Dimension L(k)= (5) Fig. 1. Spectral map of EOG component 2.2.3. EMG Artifacts To remove the EMG artifacts, the correlation of all sources with the frontalis and temporalis channels were computed and the ones which were more than 0.7 were considered as the probable EMG sources. Commonly, EMG sources have higher power at high frequencies. Therefore, to precisely detect EMG sources, in addition to the correlation criterion, their brain map were investigated[17]. The scalp map and power spectrum of one of the detected EMG artifacts is shown in Fig. 2. (b) Fig. 2. An EMG source (a)Scalp map,(b) Activity Power Spectral Methods This study is started from the data acquisition part in which 28 healthy subjects participated. We record their EEG signals through the resting condition (without imposing any pain stimulus) and pain condition. Due to the presence of artifact and noise in the recorded signals, we apply independent component analysis (ICA) to EEG in order to remove the effect of electrooculogram (EOG), electromyogram (EMG) and movement artifacts. Non-artifact sources were projected back to electrode space and various features were extracted from them. To remove the redundancy and increasing the discriminability, an approach for selecting discriminative ones, Sequential Forward Selection(SFS) was applied. The candidate classifiers were support vector machine (SVM) and one nearest neighbor (1NN). 3.1. Features The features used in this research are as follows; band power of the pain sources in five bands (Delta, Theta, Alpha, Beta, Gamma), fractal dimension, Shannon entropy, approximate entropy and spectral entropy. As a brief description to the features, Five frequency bands including Delta (0-4 Hz), Theta (4-8 Hz), Alpha (8-13 Hz), Beta (13-30 Hz), and Gamma (>30Hz) were elicited for each time frame, from each channel. [17]. Shannon entropy [18] measures the amount of irregularity in a distribution. Fractal dimensionmeasures the irregularity or roughness of a signal in a time frame[19]. The table below, demonstrates the brief procedure of calculating the features. Where P()are the probabilities occurred in the ith bin. is thethe average length, L(k) is the average length. 3.2. Feature selection The high number of features extracted in this study, from 30 channels within each time frame caused a high amount of redundancy. Search strategies need an objective function to select the suitable subset of features. This objective function is usually a statistical/ information/distance based criterion or the classifiers feedback, which are called filter and wrapper, respectively. Filter methods are fast and does not bias to the classifier type, while wrapper methods usually provide better results at high computational complexity cost. 3.2.1. Sequential Forward Selection (SFS) Sequential forward selection mechanism starts with empty set of features and repeatedly adds the most significant features to reach the criterion[20]. Here the criterion is selected as the classification accuracy with the objective of SFS selects the most discriminative algorithm. 3.3. Classifiers Two well-known classifiers, 1-NN and SVM, were used in this study. 1-NN is a local and nonlinear classifier, which is proper for classifying multimodal distributed samples[41]. From another angle, SVM with a suitable kernel is capable of classifying samples of two classes with overlap, which provides a great generalization property[21]. 3.4. Classification Investigating brain map through CPT gives us valuable information about the classification possibility. Two frequency ranges, centered at 2Hz (Delta) and 9.8Hz (Alpha), are observed as the most pain dependent features [3]-[5],[8],[22],[23]. The average brain map over all the subjects, in the Delta (Fig. 3) and Alpha (Fig. 4) bands, are exhibited in pain and no pain class. a b Fig. 3. The average brain map of subjects at 2Hz (Delta band): a) Non-pain, b) pain a b Fig. 4. The average brain map of subjects at 9.8Hz (Alpha band): a) Non-pain, b)pain Fig. 3 illustrates an increase in the power of Delta band by feeling the pain, which changes the activity focus region from top to the right hemisphere. These findings were previously reported [3]-[5], [23]. In contrast, by feeling more pain, the power of Alpha band is decreased in the frontal lobe and increased in occipital lobes, as shown in Fig. 4, which is as the results obtained in former studies [3]-[5], [8], [22]-[23]. It is noted that the base of the classifier was just built up according to the detected differences on the spatial distribution of these two band power features. To use the other EEG features and find a discriminate subset of features, SFS was run. Therefore, by adding the other features, which were selected by SFS, it was expected to achieve a higher classification accuracy. Results EEG signals from 30 electrodes were recorded and then EOG and EMG artifacts were removed by the ICA method, described in Section 2. Through the preprocessing, EMG or EOG sources and the sources caused by the bad connection of an electrode on the scalp, was projected outward of the brain. The base of the classifier was just established upon the significant changes in the spatial distribution of band power features through feeling pain (Fig. 4). since reality is that applying just the selected band power features does not provide convincing results, the structure while considering the other features was proposed. The results of pain classification by the proposed structure and those band power features, which were selected through visual inspection, is shown in Table I. For now and on, all of the presented classification results in this paper is achieved by ten-times ten-folds cross validation was executed for the cross validation phase. The classification accuracies are illustrated in Table IV, once SVM was considered for all nodes and the other time 1-NN classifier was assigned. Table I. The pain classification results of only the selected band power features Classification 1-NN 3-NN SVM Pain Versus Non-pain 68 66 54 Table II shows the classification accuracies achieved by applying svm to the features that is introduced as the discriminative ones in previous studies [6]-[8], [10], [23]-[24]. Table II. The comparative results of pain and non-pain classification by applying the previous suggested features[6]-[8], [10], [23]-[24]. Suggested Band Power Features in the Previous Studies Classification Accuracy (%) Alpha band 65 Beta and Alpha bands 61 Delta and Alpha and Beta bands 68 Theta and Alpha bands 57 Delta and Beta bands 61 Alpha and Gamma bands 62 Delta, Beta and Alpha Gamma bands 59 These numerous features, in each time frame, were concatenated into successive feature vectors and therefore the classifiers were encountered with high-dimensional vectors. To remove the redundancy and customize an optimized subset of features , SFS was adopted, to select the pain dependent features and therefore improve the final results. Nevertheless, while using wrapper method, the selected feature set depends on the classifier, the selected subsets of features are not necessary equal for SVM and 1-NN. SFS was run for each classifier separately. Also, since the test and train sets are changed through different folds, the selected features in different validation folds are not identical. As all of the reports which use wrapper approach, to demonstrate the list of selected features, the common features through folds were reported. The selected features by SFS at each node are listed in Table III. and for deploying SVM at all nodes presented and the 1NN features are listed in Table IV. Table III. The selected features by SFS for SVM and 1-NN Classifier List of the selected features SVM Alpha, Delta, Beta and Gamma bands, Shannon entropy, and fractal dimension K-NN Alpha, Delta, Beta bands and Shannon entropy The achieved classification results by applying the EEG features, customized using SFS, are illustrated in Table VI. Table VI. Classification accuracy of the pain Accuracy (%) Classifier Stage 94 SVM Pain vs. Non-Pain 89 1-NN 90 3-NN As it is stated the list of selected features depends on the type of classifier. Discussion EEG signals is the only non-invasive physiological-base measuring data that quantitatively records the brain activity. Also, the research in pain measurement is still in the beginning compared to other applications such as speech processing. As it is mentioned, among the artifact removal schemes such as regression with PCA, adaptive filter and match filter, the best known method is still ICA. It provides this opportunity to eliminate different noise and artifact roots in the ICA space, where all of the sources were statistically independent. Some constraints were considered to assure us that the suspicious noisy sources were correctly selected. In other words, the variation of spatial distribution of the Delta and Alpha bands are visualized by brain map images through the time and this variation was translated into a succesfull classification. We tried to select informative features to reveal the pain changes as highlight as possible. In this regard, instead of eliciting features from the correlated EEG signals on the scalp electrodes, variety of the known features were extracted from the pain dependent EEG source signals. Moreover, instead of ad-hoc methods, a heuristic search strategy, called as SFS, was employed to automatically select the suitable features. The high classification result demnstarates the propriety of the whole process. References [1] C.S. Cleeland, Y. Nakamura, E.W. Howland, N. R. Morgan, B. A. Edwards, M. Backonja, Effects of oral morphine on cold pressor tolerance time and neuropsychological performance, Neuropsychopharmacology, vol. 15, pp. 252-262, 1996. [2] A.C.N. Chen, P. Rappelsberger, Brain and Human Pain: Topographic EEG Amplitude and Coherence Mapping, Brain Topography, vol. 7, pp.196-205, 1994. [3] A.C.N. Chen, P. Rappelsberger, O. Filz, Topology of EEG Coherence Changes May Reflect Differential Neural Network Activation in Cold and Pain Perception, Brain Topography, vol. 11 , pp. 125-132 , 1998. [4] S. Ferracuti, S. Seri , D. Mattia , G. Cruccu, Quantitative EEG modifications during the cold water pressor test: hemispheric and hand differences, Int. Journal of Psychophysiology, vol. 17, pp.261-268, 1992. [5] A.C.N. Chen, S.F. Dworkin, J. Haug, J. Gehrig, Topographic brain measures of human pain and pain responsivity, Pain, vol. 37 , pp.129-140, 1989. [6] P. Veerasarn, C.S.Stohler, The effect of experimental muscle pain on the background electrical brain activity, Pain, vol. 49 , pp.349-360, 1992. [7] P.-F Chang, L. Arendt-Nielsen, T. Graven-Nielsen, P. Svensson, A.C.N. Chen, Topographic effects of tonic cutaneious nociceptive stimulation on human electroencephalograph, Neuroscience Letters, vol. 35 , pp. 49-52, 2001. [8] W. Penga, C. Babiloni, Y. Maod, Y. Hua, Subjective pain perception mediated by alpha rhythms, Biological Psychology , vol. 109 ,pp. 141-150, 2015. [9] T. Wager, L. Atlas, M. Lindquist, M. Roy, C. Woo, E. Kross. An fMRI-Based Neurologic Signatureof Physical Pain, The new england journal of medicine, vol. 368, pp. 1388-1397, 2013. [10] E. Schulz , A. Zherdin , L. Tiemann, C. Plant , M. Ploner , Decoding an individuals sensitivity to pain from the multivariate analysis of EEG data, Cereb Cortex, vol. 22, pp. 18-23, 2012. [11] P, Ravn , R. Frederiksen , A. Skovsen , LL. Christrup , Mu. Werner , Prediction of pain sensitivity in healthy volunteers, Journal of Pain Research, vol. 5, pp. 326-313, Aug. 2012. [12] S. Walter, S. Gruss, K. Limbrecht-Ecklundt, H. C. Traue, P. Werner, A. Al-Hamadi, N. Diniz, G. Moreira da Silva, A. O. Andrade Automatic pain quantification using autonomic parameters, Psychology Neuroscience, vol. 7 , pp.363-380, Nov. 2014. [13] S.Gruss , R.Treister , P.Werner , S .Crawcour , A .Andrade , S .Walter ,Pain Intensity recognition Rates via Biopotential Feature Patterns with Support Vector Machines, Biopotential Pattern of Pain via Machine Learning, vol. 10, oct. 2015. [14] S. Makeig, AJ. Bell, T-P. Jung, TJ.Sejnowski, Independent component analysis of electroencephalographic data, Advances in Neural Information Processing Systems, vol. 8 , pp.145-151, 1996. [15] Sheng-Hsiou Hsu, Tim R. Mullen, Tzyy-Ping Jung, Gert Cauwenberghs, Real-Time Adaptive EEG Source Separation Using Online recursive Independent Component Analysis, IEEE Trans Neural Syst Rehabil Eng, vol. 24, 3, March 2016. [16] T.Jung, S.Makeig, C.Humphries, T.Martin, J. Vicente , T.Sejnowski, Removing electroencephalographic artifacts by blind source separation, Psychophysiology, vol. 37 , pp. 163-178, 2000. [17] F.Ghassemi, Independent Component Analysis of ERP for levelingVisual Sustained Attention, Amirkabir University of Technology , 2007. [18] I. A. Rezek, S. J. Roberts, Stochastic complexity measures for [33] D. Aba ´solo1, R. Hornero1, P. Espino, D. A ´ lvarez1, J.Poza, Entropy analysis of the EEG background activity in Alzheimers disease patients, Physiol Meas, vol.27, pp.241-253, 2006. [19]M. Sabeti, S. Katebi, R.Boostani, Entropy and complexity measures for EEG signal classification of schizophrenic and control participants, Elsevier Journal of Artificial intelligence in medicine, vol. 47 , pp.263-274, , 2009. [20] S. Enshaeifar, S. Kouchaki, C. Cheong Took, and S. Sanei, Quaternion Singular Spectrum Analysis of Electroencephalogram with Application in Sleep Analysis, IEEE Trans Neural Syst Rehabil Eng. Vol. 24, 1, Jan. 2016. [21] M. Gram, C. Graversen, S.S. Olesen, A.M. Drewes, Dynamic spectral indices of the electroencephalogram provide new insights into tonic pain. Clinical Neurophysiology, vol. 126, pp. 763-771, April 2015. [22] M. Huber , J. Bartling, D. Pachur, S.Woikowsky, S. Lautenbacher, EEG responses to tonic heat pain, Exp Brain Res, vol. 173, pp. 14-24, 2006. [23] R. Dowman, D. Rissacher, S. Schuckers, EEG indices of tonic pain-related activity in the somatosensory cortices,See comment in PubMed Commons belowClinical Neurophysiology, vol. 119 , pp. 1201-1212 , 2008.

Renewable Energy Essay -- Energy, Fossil Fuel, Oil, Natural Gas

The most of global energy production produces from fossil fuel such as coal, oil and natural gas. The vast fossil fuels generate energy which use for many purposes for instant residential, transportation and industrial sectors. While the rate consumption of fossil fuel higher than their formation leads to oil price crisis. Another concern of fossil fuel combustion is the impact on the environment. Global warming is a significant problem which results in increasing concentrations of greenhouse gas in the atmosphere. These problems drive researchers and societies to search alternative energy such as switching to renewable energy or carbon-free energy to replace fossil fuels. For example Nakata et al., (2011:465) show ‘low-carbon society’ that is designed to use less fossil fuel. According to Verbruggen et al., (2010:852) define renewable energy ‘is obtained from the continuing or repetitive currents of energy occurring in the natural environment’ such as wind and biomass. Many countries accept carbon-free energy as alternative energy, and are trying to develop and apply new technologies that will enable them to use renewable energy sources in the most efficient way. However switching to carbon-free energy argued that is an unrealistic way. This essay aims to assess the differences in opinion between supports and argues of renewable energy that switching to carbon-free energy is unrealistic. Firstly consider about employing renewable energy. Secondly evaluate the sustainable development of biofuel and wind energies. Finally conclude arguments on potential renewable energy to replace fossil fuels. Owing to the increase in the global population accompanied by an increase in energy demand as a result oil price crisis. Many governments... ...f renewable energy or carbon-free debate and argument. This essay has attempted to evaluate the potential renewable energy both in terms of sustainable development and reducible global warming. Renewable energy such as biofuel and wind energy can be seen as a safe, reliable and cost effective alternative to using fossil fuels for energy security. However the development of green energy has drawbacks so funds for research and develop for chance from lab-scale products into commercial products should be provided and these fuels will become increasingly expensive to use. Clearly more could be done to produce carbon-free energy and more efficient and reduced environmental impacts. Also awareness of the advantages of renewable energy has been steadily growing and it is expected that the share of renewable energy in the total generation capacity will increase in future.

The Charles Martin – Case Analysis

On the surface, the diverse culture could be seen as a turnoff to foreign impasses, but HAG, with the help of Charles Martin's life experiences and scholastic knowledge of the region saw an opportunity to grow In Uganda. But at first glance this may prove to be difficult for HAG. This was HAG'S first pursuit of business In Africa, so growing pains were almost certainly to be felt. Like many African countries, Uganda has a tumultuous history. With the dictatorship of Idol Main ruling with an iron fist, life in Uganda was difficult (Daniels, Redheaded, Ramp; Sullivan, 2011).A diverse country in terms of religious sects, Christianity is the majority, though there is large number of Muslims among many other religions (Daniels, Redheaded, &: Sullivan, 2011 In terms of language spoken, English is the official language, however many speak only an indigenous language such as Bantu or Miltonic (Daniels, Redheaded, & Sullivan, 2011). In addition the history, language, and religion, HAG Comp any had to also take into consideration the tribal normalizes as well as the business normalizes of the Uganda culture.With the pending displacement of 700 villagers (Daniels, Redheaded, & Sullivan, 2011), HAG was now faced with its first ajar hurdle that most companies will face when expanding globally. This hurdle is best described in how to best coexist with the cultural norms of a country. Instead of trying to simply impose the will of HAG Company, they assembled a package that they felt would best benefit those being displaced. That feeling was quickly changed when Charles Martin arrived because those being displaced now wanted more.This quick change of feelings by the tribe members brought to the forefront that the biggest hurdle to global expansion for HAG Company was going to be Agenda's business raciest that borderline bribery. In order to facilitate the wants and needs of the tribal members and the Uganda government, Charles Martin did everything he could to conform to and understand their culture. Charles Martin went as far to shun the high class living that other expatriates enjoyed, he stayed In a typical Uganda middle class neighborhood (Daniels, Redheaded, ; Sullivan, 2011).He also avoided the prototypical nightlife at the local night clubs; Instead he participated In tribal rituals (Daniels, Redheaded, ; Sullivan, 2011). Of the many things Charles Martin did to conform to the Uganda culture, perhaps the biggest was understanding and participating In what many In the U. S. Would consider to be bribery. He often found himself paying people who either controlled or were related to someone who controlled various aspects of the government In order to get things done quickly. Some consider it bribery, but in Uganda it is merely called a tip.By long tense types AT tongs, snares Marten gauntleted a polypropylene Attlee. I Nils attitude was attributed to his past experience in the Peace Corps, his vast knowledge of Africa, having majored in African stud ies. Even on a personal level, Charles Martin despised those who isolated themselves (Daniels, Redheaded, ; Sullivan, 2011) instead of embracing the culture of Africa. In addition to his schooling and life experiences, HAG Company promoted independence in their managers, which is in line with a polytechnic attitude. In stark contrast, James Green exhibited a geocentric attitude.Though Charles Martin had shown the ability to complete each and every task he was given to the standards of HAG Company, James Green often questioned and found issues with the way in which he accomplished those tasks. He felt that much of what Charles Martin did was in direct conflict with the core values of HAG Company (Daniels, Redheaded, ; Sullivan, 2011). James Green faced a conflict because though HAG Company promoted freedom and responsibility among its workers, it also wanted to ensure it was in line with their corporate culture.So, Just about everything Charles Martin did to accomplish the task set b efore him was in contrast to what HAG Company felt was right and also how it would be viewed in the international community. With Charles Martin participating in tribal rituals, providing he tips that so many would be view as bribes were all opposite of the culture that HAG Company, a U. S. Company was used to doing. Looking back at how Charles Martin achieved the task presented to him, one would be comfortable in saying that he was correct.Being placed in a different culture and expected accomplish difficult tasks can seem insurmountable. But, by accepting, conforming, and being flexible enough to adapt on the fly made this entire project possible. One can not attribute all of the success to Charles Martin though, HAG Company is also responsible in that it allows it braininess to act freely enough to make the decisions and be held accountable for them (Daniels, Redheaded, ; Sullivan, 2011). Though James Green had many reservations concerning the ways in which Charles Martin was acc omplishing the tasks, he never stepped in to change him.Had he done so, maybe with such an extreme action as replacing him, or even forbidding him from the start of the project to do things his way would have been disastrous. Charles Martin had the life experience and scholastic knowledge to be open to a new culture. He not only adjusted to, but embraced the Uganda culture. This benefited him growing as a person and also HAG Company by accomplishing their goal of building a dam and providing electric services to those who need it most.The next phase of the project will prove much easier to manage. Charles Martin again is the right person for the job. He has not only established a trusting relationship with those in the area as well as the government, he will be able to handle the ever changing demands of the Uganda people involved in the project. Concerns of those who think the l

Find Out What It Means to Be on Academic Probation

Find Out What It Means to Be on Academic Probation Academic probation is the most common term colleges and universities use to indicate that a student is not making the academic progress the institution requires for graduation. Academic probation often means that a students grades and/or GPA are not high enough to continue in school if his grades or GPA do not improve. Someone can be placed on academic probation for a variety of reasons, although all will be academic in nature. Nonacademic offenses could lead to disciplinary probation. No form of probation is good, as it could result in a students suspension or expulsion. What Leads to Academic Probation? A school may put a student on academic probation because of her cumulative GPA or because of her GPA in the classes required for her major. A single semester of poor grades could also lead to academic probation. Perhaps even direr: A student may end up on academic probation if he fails to meet the standards of any financial aid he is receiving- it all depends on the schools rules and what is required to remain in good academic standing. Even if a student thinks she is doing well in school, she should familiarize herself with any GPA standards she must meet, whether for her major, scholarships, an honors program, or basic academic requirements. The best strategy, of course, is to avoid any issues in the first place rather than unexpectedly ending up on probation and having to work out of it. How to Respond to Academic Probation If a student does end up on academic probation, dont panic. Being placed on academic probation is usually not the same as being asked to leave college. Students are given a probationary period- often a semester- to demonstrate that they can indeed make successful academic progress. To do so, students may need to increase their GPA by a certain amount, pass all of their classes, or meet other requirements, as determined by their school. While there will certainly be pressure to succeed- failing to boost grades or meet certain standards could result in suspension or expulsion- there are several things a student can do to make the most of this second chance. First, be clear on what is required to stay in school. The specific steps of a students academic probation, as well as how long the probationary period will last, should be outlined in the notification the student received from her school. If its unclear as to what steps to take to move out of academic probation, the student should ask as many people as possible until she finds out the information he needs. Once its clear what lies ahead, its important to ask a key question: Are there any changes the student needs to make in her day-to-day life to ensure she reaches her academic goals? For example, if the student can cut back on some extracurricular activities, social commitments, or work hours to increase study time, she may want to do so. She should ask an adviser or a trusted mentor for resource recommendations like a study group or individual tutor because extra support can go a long way in a high-stakes situation.

Homosexuality in Ancient Rome

Homosexuality in Ancient Rome Although sexual practices are often left out of discussions of history, the fact remains that homosexuality in ancient Rome did exist. However, its not quite as cut and dried as a question of gay versus straight. Instead, its a much more complex cultural perspective, in which the approval- or disapproval- of sexual activity was based upon the social status of the people performing various acts. Did You Know? The ancient Romans didnt have a word for homosexual. Instead, they based their terminology upon the role that the participants played.Because Roman society was so patriarchal, those who took on a submissive role were seen as feminine, and thus looked down upon.Although there is little documentation of female same-sex relationships in Rome, scholars have discovered love spells and letters written from one woman to another. The Roman Patriarchal Society Bettmann Archive / Getty Images The society of ancient Rome was extremely patriarchal. For men, the determination of masculinity was directly tied to how one displayed the Roman concept of virtus. This was one of several ideals that all freeborn Romans tried to follow. Virtus was partly about virtue, but also about self-discipline and the ability to govern oneself and others. To take that a step further, the active role of imperialism and conquest found in ancient Rome was often discussed in terms of sexual metaphor. Because masculinity was predicated on ones ability to conquer, homosexual activity was viewed in terms of domination. A man taking on the perceived dominant, or penetrative, role would fall under far less public scrutiny than a man who was being penetrated, or submissive; to the Romans, the action of being conquered implied that a man was weak and willing to give up his liberty as a free citizen. It also brought into question his sexual integrity as a whole. Elizabeth Cytko writes, Bodily autonomy was one of the regulatory norms of sex which helped define one’s status within society... an elite Roman male demonstrated his status because he was not allowed to be beaten, or penetrated. Interestingly, the Romans didnt have specific words that meant homosexual or heterosexual. It wasnt gender that determined whether a sexual partner was acceptable, but their social status. The Roman censors were a committee of officials who determined where in the social hierarchy someones family belonged, and occasionally removed individuals from the upper ranks of society for sexual misconduct; again, this was based on status rather than gender. In general, same-sex relationships among partners of the appropriate social status were considered normal and acceptable. Freeborn Roman men were permitted, and even expected, to be interested in sex with partners of both genders. Even once married, a Roman man might continue to maintain relationships with partners other than his spouse. However, it was understood that he was only to have sex with prostitutes, slaves, or people who were considered infamia. This was a lower social status assigned by the censors to individuals whose legal and social standing had been formally reduced or removed. This group also included entertainers such as gladiators and actors. An infamis could not provide testimony in legal proceedings, and could be subjected to the same sorts of corporal punishments usually reserved for slaves. Ancient history expert N.S. Gill points out that Instead of todays gender orientation, ancient Roman... sexuality can be dichotomized as passive and active. The socially preferred behavior of a male was active; the passive part aligned with the female. While a free Roman man was permitted to have sex with slaves, prostitutes, and infames, it was only acceptable if he took the dominant, or penetrative role. He was not allowed to have sex with other freeborn Roman men, or the wives or children of other free men. In addition, he couldnt have sex with another mans slave; this is because slaves were property, and sex with someone elses slave required the owners explicit permission. Although not extensively documented, there were homosexual romantic relationships between Roman men. Most scholars agree that same sex relationships between men of the same class existed; however, because there were so many rigid social constructs applied to such relationship, they were kept private. While same-sex marriage was not legally permitted, there are writings that indicate some men did participate in public marriage ceremonies with other men; the emperor Nero did this at least twice, as did the emperor  Elagabalus. In addition, at one point during his ongoing dispute with Mark Antony, Cicero attempted to discredit his opponent by claiming Antony had been given a stola by another man; the stola was the traditional garment worn by married women. Homosexual Relationships in Roman Women UIG via Getty Images / Getty Images There is little information available about same-sex relationships between Roman women. Although they probably happened, the Romans didnt write about it, because to them, sex involved penetration. Its likely that the Romans didnt consider sexual acts between women to actually be sex, unlike the penetrative activities between two men. Interestingly, among Roman women there are a number of sources that indicate not sexual activity but romance. Bernadette Brooten writes in Love Between Women of love spells commissioned by women to attract other women. Scholars agree that these spells provide written evidence that women from the time period were interested in romantic attachments with other women, and that they were comfortable expressing their desires. Brooten says: [The spells] do not reveal the internal dynamics of these womens relationships. Nevertheless, the spells do ... raise intriguing, although ultimately unanswerable, questions about the nature of womens erotic desires. Gender-Bending Deities LordRunar / Getty Images As in other ancient cultures, Roman deities were reflection of the social and cultural mores of the realm of men, and vice versa. Like their neighbors in Greece, Roman mythology does include instances of same-sex relationships between the gods, or between gods and mortal men. The Roman Cupid was often seen as a patron deity of passionate love between two men, and for a long time was associated with male/male lust. The word  erotic  comes from the name of Cupids Greek counterpart, Eros. The goddess Venus was honored by some women as a goddess of female-to-female love. The Greek poet Sappho of Lesbos wrote about her in her guise as Aphrodite. The virgin goddess Diana preferred the company of women, according to legend; she and her companions hunted in the woods, danced with each other, and swore of men completely. In one legend, the god Jupiter presented himself as the princess Callisto, and seduced Diana while in disguise. When King Minos pursued a nymph named Britomaris, she escaped him by jumping into the ocean. Diana rescued Britomaris from the sea, and fell in love with her. Jupiter, much like the Greek Zeus, was the king of all the gods, and regularly had flings with mortals of both genders. He changed his appearance frequently, sometimes appearing male and other times female. In one myth, he fell in love with the beautiful youth Ganymede, and stole him away to Olympus to be his cup-bearer. Sources Brooten, Bernadette J.  Love between Women: Early Christian Responses to Female Homoeroticism. University of Chicago Press, 1998.Cytko, Elizabeth.  Of Androgynes and Men: Gender Fluidity in Republican Rome ...University of Alberta, 2017, https://era.library.ualberta.ca/items/71cf0e15-5a9b-4256-a37c-085e1c4b6777/view/7c4fe250-eae8-408d-a8e3-858a6070c194/Cytko_Elizabeth_VJ_201705_MA.pdf.Hubbard, Thomas K.  Homosexuality in Greece and Rome: A Sourcebook of Basic Documents. 1st ed., University of California Press, 2003.  JSTOR, www.jstor.org/stable/10.1525/j.ctt1pp7g1.Schrader, Kyle W.  Virtus in the Roman World: Generality, Specificity, and ...The Gettysburg Historical Journal, 2016, cupola.gettysburg.edu/cgi/viewcontent.cgi?article1154contextghj.

Story vs. Plot Definitive Differences Between Them - Freewrite Store

Story vs. Plot Definitive Differences Between Them - Freewrite Store Today’s guest post is by Jackie Dever, associate editor at  Aionios Books, a small traditional-model publisher based in Southern California.    One afternoon a few years back, as I was rowing merrily down my stream of consciousness, a big ol’ rock appeared through the mist, rearing up so fast there wasn’t time to navigate around. My paper boat crashed and crumpled, leaving the SS Plotin a disintegrating, broken mess on the Great Story River. In this personal test of story vs plot, the latter came out a wreck. Even as the events leading to the story’s conclusion continued to flow past that damned rock, my unstable craft just couldn’t get around the monolith. Reckoning with the nature of imagination can be intimidating. But half the battle is understanding the elements. Aren’t story and plot synonymous, though? Can’t we count on those items for automatic symbiosis, happily married in a thrilling rush of prose? Well†¦nope. What’s the Difference Between Story and Plot? A story is the requisite timeline of events present in any narrative. No story? No novel. Because any novel, however abstract must report events of some kind. A plot expresses rationale and informs the reader why a specific list of events belongs together, what the timeline is ultimately meant to communicate. The classic example by E. M. Forster in his collected lectures, Aspects of the Novel, still says it best: â€Å"‘The king died and then the queen died’ is a story. ‘The king died, and then the queen died of grief’ is a plot.† When reading a story, Forster explains, we wonder â€Å"and then?† When evaluating a plot, we ask â€Å"why?† (PaweÅ‚ Furman) These questions sometimes fire up in the same breath, so understanding their separate sources is tricky. But as naturally as the components may appear to support each other, it’s really an author’s skill that makes them seem that way. Which means that whenever I or you or Stephen King sit down to write, we’ve got to manage both. We’ve got to keep readers engrossed in a pattern of wonderful wondering about what next? and why? for as long as we want their attention. How Plot Supports Story Nobody wants to keep asking infinitely â€Å"and then? And then? Annnnd thennn?† We’re nosy creatures; we need to know why. Unfortunately, when plot is missing from or accidentally discordant to story, the real question on a reader’s mind is â€Å"huh?† Plot delivers the nifty tricks that reassure us there’s a point to storytelling. Plot sets up the cause and effect that gives readers a sense of rightness in the story’s conclusion. The same story can be plotted in multiple ways: The king died, and then the queen died avenging him in battle. The king died, and then the queen died from the communicable disease he had spread to her when he spoke his final words close to her face. The king died, and then the queen, eager to free the lover whom the king had jealously locked in the dungeon, slipped on an icy cobblestone and died.    How Where You Begin Helps Determine Where You’ll End Up On each new fiction project, I draw broad inspiration from either a story-focused or a plot-focused angle. Both starting points have their benefits and their challenges. Starting with Story When a story inspires me, I formulate a series of events that leads to a fixed conclusion. I may not know precisely my characters’ motivations or the logic in their decisions, but I can envision the stops they’ll make along their trip. In other words, I’ll know that the queen’s death follows the king’s. The relationship between the events? To be determined. It can be a big relief to sort story out first. When I have the comfort of parameters, I can train myself to a tangible goal. And I enjoy the intellectual exercise of connecting events in a believable sequence. Still, there’s always a catch.   Even with an endpoint clear to me, I need strong supporting evidence (i.e., an effective plot) to justify my events. A few years ago, I decided to write a story about a man who sells a cottage on the beach for the sum of one penny. I savored each of the scenes I created, but in the end, I had only a weakly conceived fairy tale. The imaginative verve delighted me, but no matter how I maneuvered, I was unable to match the plot to the currents of the story. Wipeout. Starting with Plot When a plot stirs my creative juices, I know characters’ feelings and intentions. I take on my writing like a righteous but undirected college kid- searching, motivated, assured of core values and reasons, but clueless as to where the hell I’m going to end up. I’m less concerned, in fact, with where I end up than with why I end up there, so the itinerary is subject to change. Not all who wander are lost. I enjoy making narrative progress along such an organic route. Plotting my way into a story lets me be guided by emotional responses, not by a sightseer’s list of stops. I careen over waterfalls on the strength of my anger, hilarity, or wild joy. And when that passionate feeling is synchronized with the story, I praise my muses and trust the currents. But when I let emotional connections alone be my guide, I begin to wish I’d made some reservations or at least studied the map before heading out. It always sounds noble to speed off for adventure, rely on instincts to take me where I need to be. The reality hits only once I’m shivering in the rain and have no idea where I can pull ashore for the evening. Although too much predictability is stifling, it’s frustrating to lose my mental compass entirely. There’s No Wrong Way to Start It’s hard to classify any real-life creative burst quite as strictly as I’ve done above. Flashes of  both elements are usually blended in that aha! moment. But understanding the elements of each- and how they affect the writing process- is always what prepares me for the excursion ahead. Will I need to focus extensively on my characters’ whys and wherefores to guide my plot? Or will I do better to ensure that their motivations can be satisfied by the events I allow them to experience? We all write differently. As we commit to our writing practice, patterns emerge in our process and style. I happen to be a story-focused writer. Moving the plot from one moment to the next, validating my story with a logical core, is my primary struggle. (Toa Heftiba) Whatever our personal tendencies, though, recognizing  the connected-yet-distinctive elements reminds us all that we can, if necessary, experiment. You may attempt to match several stories with an intriguing plot before everything falls in place. Or you may decide to remain patient with a great story whose plot lacks the sturdiness to carry you through, search the banks of the river for a new entry point, a more fitting course. It’s okay to take apart and rearrange, to radically transplant ideas. That constant reconfiguration is the source of diverse and sparkling literature, even as the same themes repeat themselves through the ages. The love and the death, the surprise, the resignation, the magic. None of these will ever grow trite when there’s such a big world to experience and so many ways to communicate the timeless ideas. I’ll approach the many crisscrossed rivers of my fiction from a thousand angles, strapping on mechanical wings for an aerial perspective or poking down a parallel back road in a coughing Model T. Wherever (and however) we roam, may we all learn to appreciate the view.    We'd love to hear your  thoughts of the differences in the comments!      Jackie Dever is an editor and writer in Southern California. She has edited blogs, corporate materials, academic texts, novels, and biographies. She is an associate editor at  Aionios Books, a small traditional-model publisher based in Southern California. She recently finished proofreading the 2017 San Diego Book Award–winning memoir  A Few Minor Adjustments  (September 2017) by Cherie Kephart. She blogs about writing and publishing, millennial lifestyle trends, and outdoor sports.

English Legal System Essay Example | Topics and Well Written Essays - 2000 words

English Legal System - Essay Example Thus, consistency within the law is both in practice and theory, to a maximum extent is preserved and can be regarded as one of the fundamental demands of the meaning of justice, which is covered by giving equal treatment of like cases, in like manner1. UK can be said to be the birth place of the legal concept namely judicial precedent or stare decisis or ratio decidendi. Now, judicial precedent is widely followed by the common law jurisdictions around the world. The judicial precedent concept is footed upon the rule that once a court has given its verdict in a given background, the analogous verdict should be arrived at in any future litigation where the facts of the cases are alike. The judicial precedent principle is based upon the concept that if a verdict was given by a superior court, then lower court is under obligation to follow it, whereas there is no obligation on the superior court to follow the decision given by a lower court. It is to be remembered that decision given by Lord Atkin in Donoghue v Stevenson2 in 1932 as regards to â€Å"neighbour principle† which has become the reference case for the cases involving ‘negligence’ in the latter period3. A gullible consumer may under proper scenarios recoup damages for harm sustained by a defective product either it be car as held in Andrews v Hopkinson,4 or it may be an underwear as held in Grant v Australian Knitting Mills.5 Likewise , the verdict given in Salomon v Salomon & Co Ltd6 also became a precedent in subsequent cases where it was held that a company is a juristic person , has separate legal entity and a company is different from its members.7 In these cases, the courts have considered only the legal principle involved and not the particular facts of the earlier cases. Thus, the legal principle, which is known as the ratio decidendi is the crux portion of the judicial decision which is a binding precedent.8 An obiter dictum in judicial verdict deals with observation made by a judge in the course of litigation, which is not essential for the final verdict and hence is not regarded as a binding precedent. For instance, in R v Howe & Bannister9, it was held by the House of Lords that defence of duress could not be extended to murder crime and this has been regarded as the ratio decidendi of the case. Further, it was observed by the House of Lords, whether the defence should be made available to those accused who engaged in an attempt of murder and observed obiter dicta that the defence of duress should not be made available to the attempted murder also10. It is to be noted that obiter dicta is also referred by other names namely persuasive precedent, which refers to the legal principles observed by the judges which just offer some elucidation on the subject. Thus, persuasive precedents may also emanate from lower courts and also from the verdicts of other jurisdiction11. In R v Gotts12 , the House of Lords was of the view that justification under duress cannot be extended for

Illegal Immigration - For illegal immigration for America Research Paper

Illegal Immigration - For illegal immigration for America - Research Paper Example It also includes the existing laws being implemented to combat this long-term issue that has conquered America by storm. It will also document the reasons as to why the US immigration policies failed as evidenced by the increasing number of illegal immigrants from all over the world. The role of government is given an emphasis to come- up with domestic policies to ensure that security and anti-terrorism concerns of the country are dealt with by law. Lastly, it will also provide the worldwide effect of immigration in the US and the participation of the other nations on how to prevent their citizens from entering the US without legal documentation. Keywords: illegal immigration, immigration laws, amnesty, legalization, illegal immigrants. ILLEGAL IMMIGRATION IN AMERICA Since time immemorial America has been considered the land of â€Å"milk and honey† for millions of people from all across the world. Most of the citizens from poor countries aim to reach America as their end dest ination thinking that this is the place where there is more than enough for everything. It has been perceived as the land of abundance, wealth and endless opportunities. The ultimate goal of the illegal immigrants is to enter US and land a job which will earn them a substantial income to support their families in their country of origin. However, at present time, we all know that America has been experiencing economic recession and even its countrymen were not spared of this crisis, as many became unemployed, homeless and suffered financial distress. Dubbed as the â€Å"nation of nations†, Lemay (2009, p. xv) has reported that the United States has absorbed immigrants from 170 countries across the globe. It has been the home of almost 70 million legal immigrants and experienced the influx of an estimated 11 million of illegal immigrants. The unauthorized flow of illegal immigrants entering the America is caused by inefficiencies of the immigration system of the US government to enact stricter laws and policies to address the current problems. History Ngai (2007, p.2) has reported that as early as 1920’s, the unauthorized entry has become the most common form of illegal immigration which has been condemned by both the state and the society. These unauthorized immigrants may either be welcome or unwelcomed by the US. They became in demand by the economic sector as their labor is cheap and replaceable. In the middle decades of the 20th century, they were only billeted in the western and southwestern agriculture. But at present, illegal immigrants have evolved and can be found in almost every region in the United States. Based on the records, the United States documented the number of immigrants who earned the status of authorized immigrants. â€Å"An approximate of 70 million of them forms part of the legal immigrants, but as history would tell us, the flow of unauthorized entrants likewise increased. According to LeMay (2007 p.1), the heavy traffi c of these illegal immigrants commenced after 1970, and the massive volume was recorded at present time. Today, there is an estimate of 10.5 to 11 million illegal immigrants living in the US. The Evolution of US Immigration Laws In the study made by Kenney (2009, pp. 21-23), she highlighted the significant immigration laws: The Immigration and International Act of 1965 was the law which set the limit on the immigrants coming from the Western Hemisphere, including Mexico. It set a limit of 20,000

Millennium Development Goals (MDGs) Essay Example | Topics and Well Written Essays - 1500 words

Millennium Development Goals (MDGs) - Essay Example cal and measurable approaches, to diminishing poverty around the world, while improving education, health, and other crucial social aspects of people’s lives. Some of the specific goals defined included eradication of extreme poverty and hunger, with the primary aim being to pave way and bolster education for all. Another MDG that is discussed in further detail in this report is the achievement of universal fundamental education. The UN initially set the timeline for achievement of these and other MDGs as a decade and a half, meaning that signatories to the organization were expected to attain stipulated objectives by 2015. Having ushered in 2015, it is imperative to assess whether these MDGs have been achieved and the barriers that have impeded successful implementation in some environments, such as access, quality, cost, and stability in respective nations. According to a report by UNICEF (2010), countries around the globe were fairly successful in alleviating poverty half a decade earlier than the projected year. The diminished poverty levels were evident from the significant decrease in proportion of people living under the poverty line. For instance, in 2010 about 21% of the populace in developing countries sustained themselves with the minimal 1.25 USD per day or lower. During the 1990s this population percentage was at 43%, showing that it halved by 2010 thus demonstrating significant poverty reduction. More than a billion individuals internationally still live in life-threatening poverty, and many of them experience deprivation and are susceptible to ecological or price shocks. Under nutrition remains one of the most serious global issues but least talked about public health challenges. Nearly one-third of offspring in emerging countries are underfed or diminutive (low height that does not match with age), and under nutrition acc ounts for one-third of all infant deaths. The World Bank Group is operating with the global community to end life-threatening

Apple Inc. AAPL Research Paper Example | Topics and Well Written Essays - 750 words

Apple Inc. AAPL - Research Paper Example These are supplemented by software platforms like the OS X and iOS operating systems. Te products produced by Apple also vary over a wide range of other products. In this analysis of Apple Inc, this paper will focus on its price history and ratio analysis, which will help in determining its profitability and competitiveness in the market. The competitive position built by Apple Inc is one based on reading the market and understanding what the customer needs in regards to technology. This can be seen from the change in product lines that the company has been going through since its inception. With the advent of computers and the market for personal computers, the company started producing the Macintosh that helped take over the computer market. This changed to the production of laptops in response to the market, and currently, the company is at the forefront in producing mobile phones. The main competitor to the company’s iphone is the threat of competition from Android based phones and applications. An analysis of Apple Inc’s financial history in the last twelve months reveals that the company has had its best performance to date. In august, the stock touched a record high of $665 per share, an indicator of the market conditions that favor the company. However, the bullish market caused the stock to plummet from the august and September highs to another low, but with the regaining market, the company is expected to bounce

ELL Concepts Research Paper Example | Topics and Well Written Essays - 500 words

ELL Concepts - Research Paper Example The notion of â€Å"providing practice† is generally defined as the praxis of supplying practice-based items so that learners have â€Å"multiple opportunities† (Lanin-Thompson & Vaughn, 2007). A guided practice includes the finding of, or comprehending, the subtle distinction of the words â€Å"downpour,† â€Å"drizzle,† and â€Å"sprinkle,† which according to Lanin-Thompson & Vaughn are different descriptions of the fall of precipitation. Since the characteristic of explicit skill instruction is routine or repetitive, English Language Learners are gradually able to acquire these words. Giving this kind of learners an ample time for them to practice is undoubtedly empirical. Muniz-Swicegood argues that students who received explicit skill instruction and guided practice â€Å"can then practice the skills and strategies they have learned† (as cited in Lanin-Thompson & Vaughn). This practice could be done substantially through group discussion or interaction. Such strategy certainly increases the interaction among English Language Learners. Question 2 The basic stages of second language acquisition have great implication both to the teacher’s pedagogy and to the L2 student.

Understanding and interpreting financial statements Dissertation

Understanding and interpreting financial statements - Dissertation Example Understanding and interpreting financial statements The information contained in the financial statements can be used by financial analysts to perform ratio analysis. The purpose of this paper is to analyze the financial performance of Morrisons Inc. Company Profile: Morrisons Morrisons was founded in 1899 by William Morrison. The first supermarket chain was opened in 1961. Today the company has become the 4th largest supermarket retailer in the United Kingdom . The initial public offering of the company occurred in 1967. The company serves over 10 million customers each week across its network of 382 stores. Morrisons helps the United Kingdom’s economy by providing the community with 124,000 jobs. One of the aspects of the Morrisons operation that makes this company different is that the firm owns its supply chain logistics. The company has its own packing facilities, baking capabilities, distribution centers, and fleet of trucks to deliver fresh goods to its stores. Ratio Selection The use of ratio analysis can help a person evaluate the financial performance of a company. To perform ratio analysis one must retrieve the financial statements of the company. The two financial statements that are mostly used when performing ratio analysis are the income statement and the balance sheet. There are different categories of ratios that an analyst can utilize. The five categories of ratios are profitability, solvency, efficiency, liquidity, financial gearing, and investment. To evaluate Morrisons this paper uses a variety of financial ratios from the different categories mentioned. A profitability ratio that will be used in the paper is net margin. Net margin is calculated dividing net income by sales (Besley & Brigham, 2000). It is preferable to have a high net margin because higher net margins imply that the company is more profitable. Another profitability ratio of importance is the gross profit. The gross profit is calculated with the following formula. (Sales – CGS) / Sales (Weygandt & Kieso & Kimmel , 2002). High profit margins are preferable. Two additional metrics that will be used to evaluate Morrisons is return on assets and return on equity. Return on assets is calculated dividing net income by total assets, while return on equity is calculated dividing net income by total equity (Dictionary, 2011). An efficiency ratio that will be used to evaluate Morrisons is sales revenue per employee. Obtaining high sales revenue per employee is preferable because it implies that each employee of the company is helping the firm generate more money. Another efficiency ratio that will be used in the analysis of Morrisons is sales revenue to capital employed. The ratio is calculated dividing revenues by capital. A liquidity ratio that was selected for the Morrisons ratio analysis was the current ratio. The current ratio determines the capabilities of the company to pay off its short term debt (Investopedia, 2011). The formula to calculate current ratio is current assets divided by current liability. Two gearing ratios that will be used in the analysis of Morrisons are the debt ratio and the debt to equity ratio. The debt ratio is calculated by dividing total assets by total liabilities. The debt ratio measures the ability of the company to pay off its long term debt (Garrison & Noreen, 2003). The debt to equity ratio is calculated dividing total assets by total equity. The investment ratios chosen to perform the ratio analysis on

Apple Inc. AAPL Research Paper Example | Topics and Well Written Essays - 750 words

Apple Inc. AAPL - Research Paper Example These are supplemented by software platforms like the OS X and iOS operating systems. Te products produced by Apple also vary over a wide range of other products. In this analysis of Apple Inc, this paper will focus on its price history and ratio analysis, which will help in determining its profitability and competitiveness in the market. The competitive position built by Apple Inc is one based on reading the market and understanding what the customer needs in regards to technology. This can be seen from the change in product lines that the company has been going through since its inception. With the advent of computers and the market for personal computers, the company started producing the Macintosh that helped take over the computer market. This changed to the production of laptops in response to the market, and currently, the company is at the forefront in producing mobile phones. The main competitor to the company’s iphone is the threat of competition from Android based phones and applications. An analysis of Apple Inc’s financial history in the last twelve months reveals that the company has had its best performance to date. In august, the stock touched a record high of $665 per share, an indicator of the market conditions that favor the company. However, the bullish market caused the stock to plummet from the august and September highs to another low, but with the regaining market, the company is expected to bounce

Understanding and interpreting financial statements Dissertation

Understanding and interpreting financial statements - Dissertation Example Understanding and interpreting financial statements The information contained in the financial statements can be used by financial analysts to perform ratio analysis. The purpose of this paper is to analyze the financial performance of Morrisons Inc. Company Profile: Morrisons Morrisons was founded in 1899 by William Morrison. The first supermarket chain was opened in 1961. Today the company has become the 4th largest supermarket retailer in the United Kingdom . The initial public offering of the company occurred in 1967. The company serves over 10 million customers each week across its network of 382 stores. Morrisons helps the United Kingdom’s economy by providing the community with 124,000 jobs. One of the aspects of the Morrisons operation that makes this company different is that the firm owns its supply chain logistics. The company has its own packing facilities, baking capabilities, distribution centers, and fleet of trucks to deliver fresh goods to its stores. Ratio Selection The use of ratio analysis can help a person evaluate the financial performance of a company. To perform ratio analysis one must retrieve the financial statements of the company. The two financial statements that are mostly used when performing ratio analysis are the income statement and the balance sheet. There are different categories of ratios that an analyst can utilize. The five categories of ratios are profitability, solvency, efficiency, liquidity, financial gearing, and investment. To evaluate Morrisons this paper uses a variety of financial ratios from the different categories mentioned. A profitability ratio that will be used in the paper is net margin. Net margin is calculated dividing net income by sales (Besley & Brigham, 2000). It is preferable to have a high net margin because higher net margins imply that the company is more profitable. Another profitability ratio of importance is the gross profit. The gross profit is calculated with the following formula. (Sales – CGS) / Sales (Weygandt & Kieso & Kimmel , 2002). High profit margins are preferable. Two additional metrics that will be used to evaluate Morrisons is return on assets and return on equity. Return on assets is calculated dividing net income by total assets, while return on equity is calculated dividing net income by total equity (Dictionary, 2011). An efficiency ratio that will be used to evaluate Morrisons is sales revenue per employee. Obtaining high sales revenue per employee is preferable because it implies that each employee of the company is helping the firm generate more money. Another efficiency ratio that will be used in the analysis of Morrisons is sales revenue to capital employed. The ratio is calculated dividing revenues by capital. A liquidity ratio that was selected for the Morrisons ratio analysis was the current ratio. The current ratio determines the capabilities of the company to pay off its short term debt (Investopedia, 2011). The formula to calculate current ratio is current assets divided by current liability. Two gearing ratios that will be used in the analysis of Morrisons are the debt ratio and the debt to equity ratio. The debt ratio is calculated by dividing total assets by total liabilities. The debt ratio measures the ability of the company to pay off its long term debt (Garrison & Noreen, 2003). The debt to equity ratio is calculated dividing total assets by total equity. The investment ratios chosen to perform the ratio analysis on

Racism in Roll of Thunder Essay Example for Free

Racism in Roll of Thunder Essay Mildred Taylors remarkable novel, Roll of Thunder, Hear My Cry, annotates, portrays, and demonstrates the vivid image of the ugly race prejudice, effectively, that the African Americans experienced in the 1930s, during the American Depression. In Taylors enthralling novel, racism comes across as a major and influential theme as the novel progresses and revolves around a young girl, Cassie Logan, who matures with racial conflict around her. Racism is apparent from the beginning of the novel. It is depicted from the beginning that African Americans are treated terribly, and they must work extremely hard, to earn the money they need to provide their family, with shelter, and food. Papa must work away from home to earn himself a good salary to keep the Logans own land, rather than working as sharecroppers on someone elses land. The second example of the callous segregation is evident, as it is seen that the elite white community have transport to school, while the harshly treated African Americans are deprived of this service, and are forced to walk to school. Also, the whites are inconsiderate, intentionally splashing mud on the blacks clothes. The Berrys burnings is a significant incident revealing the cruel manner the white community behave towards the African Americans, burning them taking a match to them, without any justifiable reason, portraying the discrimination between the people. At school, an important instance of racism takes place, when the students of the black school, The Great Faith Elementary School, received new books. These books were in the poorest condition, as they were the left-overs of the whites. The inside cover of the books were highly provocative, both insulting and offensive to the African Americans, using repulsive comments to describe their race such as nigra. The law also seems to be in favour of the white community, showing the extensive segregation between the whites and blacks. It is evident when Mr. Morrison explains why he lost his job Mr. Morrison was blamed in a fight with the whites, although it wasnt his fault. There are rarely any whites who are friendly with the whites, and those who are, are despised. This is the case with Jeremy, who walks to school everyday with the blacks. He is often bullied, mocked, and teased at school, and is beaten at home. The abhorrence of the underprivileged blacks by the whites is remarkably large, throughout the novel. As the novel progresses it is seen that Papa tries to explain to Stacey to hang out less with Jeremy, We Logans dont have much to do with the white folks. You know why? Papa says, believing that whites and blacks will never really be friends, Cause white folks mean trouble, with this it also demonstrates hatred between the two races. The intensity of racial discrimination is massive when TJ talks about the night men. The whites tarred and feathered him, making the African Americans feel inferior treating them of no value and worthless. Cassie, herself, is a victim of one of the racism incidents. On her visit to Strawberry, she is forced to apologize repeatedly to Lillian Jean, a white, humiliating herself greatly. Even her family, who are strong-willed, cannot prevent such things from happening trying to stay away from consequences. Cassie is mentally hurt after this situation. Racist comments are at is summit as the story progresses. Kaleb Wallace, to Mr. Morrison, sputtered, You big black nigger, I oughta cut your heart out for what you done! My brothers laid up like they is and you still runnin around free as a white man. Downright sinful, thats what it is! Why? I oughta gun you down right where you sit. This quote shows the filthy comments the whites use towards the blacks. As the story nears its conclusion, TJ gets influenced by the white community, and gets into stealing. TJ goes to a Barnetts store with his white friends, to get himself the pearl handed pistol. At the shop, the whites wearing a mask kill Mr. Barnett, a white man. TJ Avery is immediately entirely blamed for the sequence of events. This shows, again, the law in much favour of the whites as the police dont even look into the issue they dont care who is guilty, but immediately find a black man to blame. If the roles had been reversed, circumstances and the events that took place would have been completely different. The whites simply want to punish some blacks, and they can do so easily, as no one dares to stop them. Throughout the story, there are several racist remarks passed to the African Americans emphasizing the conditions they faced. Life for the African Americans in the 1930s was completely unjust. Judgment based solely on physical appearance exists, to date, and is still a controversial issue.

Sequence Alignment and Dynamic Programming

Sequence Alignment and Dynamic Programming Introduction Sequence alignment Sequence alignment is a standard method to compare two or more sequences by looking for a series of individual characters or character patterns that are in the same order in the sequences [1]. Also, it is a way of arranging two or more sequences of characters to recognize regions of similarity [2]. Importance of sequence alignment Sequence alignment is significant because in bimolecular sequences (DNA, RNA, or protein), high sequence similarity usually implies important functional or structural similarity that is the first step of many biological analysis [3]. Besides, sequence alignment can address significant questions such as detecting gene sequences that cause disease or susceptibility to disease, identifying changes in gene sequences that cause evolution, finding the relationship between various gene sequences that can indicate the common ancestry [4], detecting functionally important sites, and demonstrating mutation events [5]. Analysis of the alignment can reveal important information. It is possible to identify the parts of the sequences that are likely to be important for the function, if the proteins are involved in similar processes .The random mutations can accumulate more easily in parts of the sequence of a protein which are not very essential for its function. In the parts of the sequence that are essential for the function hardly any mutations will be accepted because approximately all changes in such regions will destroy the function [6]. Moreover, Sequence alignment is important for assigning function to unknown proteins [7]. Protein alignment of two residues implies that those residues perform similar roles in the two different proteins [8]. Methods The main purpose of sequence alignments methods is finding maximum degree of similarities and minimum evolutionary distance. Generally, computational approaches to solve sequence alignment problems can be divided into two categories: global alignments and local alignments. Global alignments traverse the entire length of all query sequences, and match as many characters as possible from end to end. These alignment methods are most useful when the sequences have approximately the same size or they are similar. The alignment is performed from beginning of the sequence to end of the sequences to find out the best possible alignment. On the other hand, Local alignments find the local regions with high level of similarity. They are more useful for sequences that are suspected to contain regions of similarity within their larger sequence context. [9] Besides, pairwise sequence alignment is used to find the regions of similarity between two sequences. As the number of sequences increases, comparing each and every sequence to every other may be impossible. So, we need multiple sequence alignment, where all similar sequences can be compared in one single figure or table. The basic idea is that the sequences are aligned on top of each other, so that a coordinate system is set up, where each row is the sequence for one protein, and each column is the same position in each sequence. [10] There are many different approaches and implementations of the methods to perform sequence alignment. These include techniques such as dynamic programming , heuristic algorithms (BLAST and FASTA similarity searching), probabilistic methods, dot-matrix methods, progressive methods, ClustalW , MUSCLE , T-Coffee , and DIALIGN. Dynamic programming Dynamic programming (DP) is a problem solving method for a class of problems that can be solved by dividing them down into simpler sub-problems. It finds the alignment by giving some scores for matches and mismatches (Scoring matrices).This method is widely used in sequence alignments problems. [11] However, when the number of the sequences is more than two, multiple dimensional Dynamic programming in infeasible because of the large storage and computational complexities.[16] Dynamic programming algorithms use gap penalties to increase the biological meaning [9]. There are different gap penalties such as linear gap, constant gap, gap open and gap extension. The gap score is a penalty given to alignment when there is insertion or deletion. There may be a case where there are continuous gaps all along the sequence during the evolution, so the linear gap penalty would not be suitable for the alignment. Therefore, gap opening penalty and gap extension penalty has been introduced when there are continuous gaps. The gap opening penalty is applied at the start of the gap, and then the other gap following it is given with a gap extension penalty which will be less compared to the open penalty. Different gap penalty functions require different dynamic programming algorithms [12]. Also; there is a substitution matrix to score alignments. The mainly used predefined scoring matrices for sequence alignment are PAM (Point Accepted Mutation) and BLOSUM (Blocks Substitut ion Matrix). The two algorithms, Smith-Waterman for local alignment and Needleman-Wunsch for global alignment, are based on dynamic programming. Needleman-Wunsch algorithm requires alignment score for a pair of residues to be equal or more than zero. No gap penalty is required, and score cannot decrease between two cells of pathway. Smith-Waterman requires a gap penalty to work efficiently. Residue alignment score may be positive or negative .Score can increase, decrease, or stay level between two cells of pathway [13]. Sequence Alignment Problems For an n-character sequence s, and an m-character sequence t , we construct an (n+1)Ãâ€"(m+1)matrix . Global alignment: F ( i, j ) = score of the best alignment of s[1i ] with t[1j] Local alignment: F ( i, j ) = score of the best alignment of a suffix of s[1i ] and a suffix of t[1j] There are three steps in the sequence alignments algorithms: Initialization In the initialization phase, we assign values for the first row and column of the alignment matrix .The next step of the algorithm depends on this. Fill In the fill stage, the entire matrix is filled with scores from top to bottom, left to right with appropriate values that depend on the gap penalties and scoring matrix. Trace back For each F ( i, j ), save pointers to cell that resulted in best score . For global alignment, we trace pointers back from F (m, n) to F(0, 0) to recover sequence alignments . For local alignment, we are looking for the maximum value of the F (i, j) that can be anywhere in the matrix. We trace pointers back from F (i, j) and stop when we get to a cell with value 0. Local alignment with scoring matrix After creating and initializing the alignment matrix ( F ) and trace back matrix, the score of F (i, j) for every cell is calculated as follows: For i = 1 to n+1 For j = 1 to m+1 left_score= F[i][ j-1] gap, diagonal_score=F[i-1[ j-1] + PAM250(s[i], t[j]), up_score= F[i-1][ j] gap scores=max[ 0, left_score, diagonal_score, up_score] Also, we should keep the reference to each cell to perform backtracking. traceback_matrix[i][j]= scores.index(F[i][j]) After filling the F matrix, we find the optimal alignment score and the optimal end points by finding the highest scoring cell, maxi,jF(i , j) . best_score has a default value equals to -1 . if F [i][j] > best_score: best_score= F [i][j] i_maximum_score, j_maximum_score = i, j To recover the optimal alignment, we trace back from i_maximum_score, j_maximum_score position , terminating the trace back when we reach a cell with score 0 . The time and space complexity of this algorithm is O(mn) which m is the length of sequence s , and n is the length of sequence t. Local alignment with affine gap penalty For this problem, there are gap opening penalty and gap extension penalty. The gap opening penalty is applied at the start of the gap, and then the other gap following it is given with a gap extension penalty. Initialization: There are Four different matrices: up_score , left_score ,m_score , trace_back Filling matrix: For i = 1 to n+1: up_score[i][0] = -gap_opening_penalty-(i-1)*gap_extension_penalty For j = 1 to m+1: left_score[0][j] = -gap_opening_penalty-(j-1)*gap_extension_penalty For i = 1 to n+1: For j = 1 to m+1: up_score [i][j] = max( [up_score [i][j-1] gap_extension_penalty, m_score[i][j-1] gap_opening_penalty] ) Left_score[i][j] = max( [left_score[i-1][j] gap_extension_penalty, m_score[i-1][j] gap_opening_penalty] ) m_score[i][j] = BLOSUM62 (s[i], t[j])) +max( m_score [i-1][j-1], left_score [i-1][j-1], up_score [i-1][j-1] ) scores = [left_score[i-1][j-1], m_score[i-1][j-1] ,up_score[i-1][j-1], 0] We find the highest scoring cell, the position of that cell,and the best alignment by following the same steps as we accomplished in the previous problem. The time and space complexity of this algorithm is O(mn). Global alignment with constant gap penalty In this case every gap receives a fixed score, regardless of the gap length For i = 1 to m+1: alignment_matrix[i][0] = -gap_penalty For i = 1 to n+1: alignment_matrix[0][j] = -gap_penalty For i = 1 to n+1: For j = 1 to m+1: scores = [alignment_matrix[i][j-1] gap_penalty,alignment_matrix[i-1][j] gap_penalty, alignment_matrix[i-1][j-1] + BLOSUM62 (s[i], t[j]),) alignment_matrix[i][j] = max(scores) alignment_matrix[m][n] holds the optimal alignment score. The time and space complexity of this algorithm is O(mn) which m is the length of sequence s , and n is the length of sequence t. Global alignment with scoring matrix In this problem there is a linear gap that each inserted or deleted symbol is charged g; as a result, if the length of the gap L; the total gap penalty would be the product of the two gL. For i = 1 to m+1: alignment_matrix[i][0] = -i*gap_penalty For i = 1 to n+1: alignment_matrix[0][j] = -j*gap_penalty scores = [alignment_matrix[i][j-1] gap_penalty,alignment_matrix[i-1][j] gap_penalty, alignment_matrix[i-1][j-1] + BLOSUM62 (s[i], t[j]),) alignment_matrix[i][j] = max(scores) alignment_matrix[m][n] holds the optimal alignment score. The time and space complexity of this algorithm is O(mn) which m is the length of sequence s , and n is the length of sequence t. Global alignment with scoring matrix and affine gap penalty There are Four different matrices: up_score , left_score ,m_score , trace_back Filling matrix: For i = 1 to n+1: up_score[i][0] = -gap_opening_penalty-(i-1)*gap_extension_penalty For j = 1 to m+1: left_score[0][j] = -gap_opening_penalty-(j-1)*gap_extension_penalty For i = 1 to n+1: For j = 1 to m+1: up_score [i][j] = max( [up_score [i][j-1] gap_extension_penalty, m_score[i][j-1] gap_opening_penalty] ) Left_score[i][j] = max( [left_score[i-1][j] gap_extension_penalty, m_score[i-1][j] gap_opening_penalty] ) m_score[i][j] = BLOSUM62 (s[i], t[j])) +max( m_score [i-1][j-1], left_score [i-1][j-1], up_score [i-1][j-1] ) maximum_alignment_score = max(m_score[m][n], left_score[m][n], up_score[m][n]) The time and space complexity of this algorithm is O(mn) which m is the length of sequence s , and n is the length of sequence t. The above algorithms require too much time for searching large databases so we cannot use these algorithms. There are several methods to overcome this problem. Heuristic Method It is an algorithm that gives only approximate solution to a problem. Sometimes we are not able to formally prove that this solution actually solves the problem, but since heuristic methods are much faster than exact algorithms, they are commonly used . FASTA is a heuristic method for sequence alignment .The main idea of this method is choosing regions of the two sequences that have some degree of similarity, and using dynamic programming to compute local alignment in these regions. The disadvantage of using these methods is losing significant amount of sensitivity. Parallelization is a possible solution for solving this problem.[14] Parallel Algorithm In this paper [ 15 ] a parallel method is introduced to reduce the complexity of the dynamic programming algorithm for pairwise sequence alignment. The time consumption of sequential algorithm mainly depends on the computation of the score matrix .For calculating the score of each cell, the computation of F(i,j) can be started only when F(i-1,j-1), F(i-1,j) and F(i,j-1) acquire their values. Consequently, it is possible to conduct the computation of score matrix sequentially in order of anti-diagonals .So, the values in the same anti-diagonal can be calculated simultaneously. ( Figure 1 ) Figure1 .Computing score matrix in parallel manner .The values of the cells marked by à ¯Ã†â€™Ã‚   can be computed simultaneously. There are two models for problem solving using parallel method that improve the performance of the pairwise alignment algorithm. Pipeline model: Each row of the score matrix is computed successively by a processor, which blocks itself until the required values in the above row are computed. Anti-diagonal model: From the left-top corner to the right-bottom corner of score matrix, all processors compute concurrently along an anti-diagonal of the matrix. Each idle processor selects a cell from the current anti-diagonal and computes its value. When all values in current anti-diagonal are computed, the computation moves on to next anti-diagonal. In the algorithm that is based on the pipeline model, the score matrix is partitioned into several blocks by column and several bands by row. All the bands distributed to multiple processors, and each processor computes the block in its own band simultaneously. By applying parallel algorithm, The time complexity is O(n) when n processor is used. [15] Progressive Method For solving multiple sequence alignment problems, the most common algorithm used is progressive method. This algorithm consists of three main stapes. First, comparing all the sequences with each other, and producing similarity scores ( distance matrix) . This stage is parallelized. The second stapes groups the most similar sequences together using the similarity scores and a clustering method such as Neighbor-Joining to create a guide tree. Finally, the third stage sequentially aligns the most similar sequences and groups of sequences until all the sequences are aligned. Before alignment with a pairwise dynamic programming algorithm, groups of aligned sequences are converted into profiles. A profile represents the character frequencies for each column in an alignment. In the final stage, for aligning groups of sequences, trace back information from full pairwise alignment is required.[ 17 ] ClustalW This algorithm that has become the most popular for multiple sequence alignment implements progressive method. The time complexity of this method is O (N 4 + L 2) and the space complexity is O (N2 + L 2). [18] Conclusion By comparing the different methods to implement pairwise sequence alignment and multiple sequence alignment , we can conclude that using parallel algorithms that implement pipeline model or anti-diagonal model are effective algorithm for performing pairwise sequence alignments. The algorithms that implement progressive method such as ClustalW are effective algorithm for solving multiple sequence alignments problems. References Robert F. Murphy, Computational Biology, Carnegie Mellon University www.cmu.edu/bio//LecturesPart03.ppt http://en.wikipedia.org/wiki/Sequence_alignment Dan Gusfield, Algorithms on Strings, Trees and Sequences: Computer Science and Computational Biology (Cambridge University Press, 1997). http://cs.calvin.edu/activities/blasted/intro03.html http://www.embl.de/~seqanal/courses/commonCourseContent/commonMsaExercises.html Per Kraulis , Stockholm Bioinformatics Center, SBC ,http://www.avatar.se/molbioinfo2001/seqali-why.html http://iitb.vlab.co.in/?sub=41brch=118sim=656cnt=1 Andreas D. Baxevanis, B. F. Francis Ouellett ,Bioinformatics: A Practical Guide to the Analysis of Genes and Proteins http://amrita.vlab.co.in/?sub=3brch=274sim=1433cnt=1 David S.Moss, Sibila Jelaska, Sandor Pongor, Essays in Bioinformatics, ISB 1-58603-539-8 http://amrita.vlab.co.in/?sub=3brch=274sim=1431cnt=1 Burr Settles, Sequence Alignment, IBS Summer Research Program 2008, http://pages.cs.wisc.edu/~bsettles/ibs08/lectures/02-alignment.pdf Aoife McLysaght, Biological Sequence Comparision/Database Homology Searching, The University of Dublin, http://www.maths.tcd.ie/~lily/pres2/sld001.htm Rapid alignment methods FASTA and BLAST http://www.cs.helsinki.fi/bioinformatiikka/mbi/courses/07-08/itb/slides/itb0708_slides_83-116.pdf Yang Chen, Songnian Yu, Ming Ling, Parallel Sequence Alignment Algorithm For Clustering System, School of Computer Enginnering and science, Shanghai University Heitor S. Lope, Carlos R ,Erig Lima , Guilherme L. Morit , A Parallel Algorithm for Large-Scale Multiple Sequence Alignment , Bioinformatics Laboratory/CPGE Federal University of Technology – Paran ÃÅ'  Scott Lloyd, Quinn O Snel , Accelerated large-scale multiple sequence alignment Kridsadakorn Chaichoompu, Surin Kittitornkun, and Sissades Tongsima ,MT-ClustalW: Multithreading Multiple Sequence Alignment