902 resultados para Math Applications in Computer Science


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A tanulmány Magyarország egyik legnagyobb foglalkoztatójának megrendelésére készült abból a célból, hogy milyen megoldásokkal lehetne a vállalati működést hatékonyabbá tenni. Ennek keretében a szerzők megvizsgálták, hol tart ma a HR adatbányászati kutatás a világban. Milyen eszközök állnak rendelkezésre ahhoz, hogy a munkavállalói elmenetelt előre jelezzék, illetve figyeljék, valamint milyen lehetőség van a hálózati kutatások felhasználására a biztonság területén. Szerencsés, hogy a vállalkozói kérdések és erőforrások találkozhattak a kutatói szféra aktuális kutatási területeivel. A tanulmány szerzői úgy gondolják, hogy a cikkben megfogalmazott állítások, következtetések, eredmények a jövőben hasznosíthatók lesznek a vállalat és más cégek számára is. _____ The authors were pleased to take part in this research project initiated by one of Hungary’s largest employer. The goal of the project was to work out BI solutions to improve upon their business process. In the framework of the project first the authors made a survey on the current trends in the world of HR datamining. They reviewed the available tools for the prediction of employee promotion and investigated the question on how to utilize results achieved in social network analysis in the field of enterprise security. When real business problems and resources meet the mainstream research of the scientific community it is always a fortunate and it is rather fruitful. The authors are certain that the results published in this document will be beneficial for Foxconn in the near future. Of course, they are not done. There are continually new research perspectives opening up and huge amount of information is accumulating in the enterprises just waiting for getting discovered and analysed. Also the environment in which an enterprise operates is dynamically changing and thus the company faces new challenges and new type of business problems arise. The authors are in the hope that their research experience will help decision makers also in the future to solve real world business problems.

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Cardiac troponin I (cTnI) is one of the most useful serum marker test for the determination of myocardial infarction (MI). The first commercial assay of cTnI was released for medical use in the United States and Europe in 1995. It is useful in determining if the source of chest pains, whose etiology may be unknown, is cardiac related. Cardiac TnI is released into the bloodstream following myocardial necrosis (cardiac cell death) as a result of an infarct (heart attack). In this research project the utility of cardiac troponin I as a potential marker for the determination of time of death is investigated. The approach of this research is not to investigate cTnI degradation in serum/plasma, but to investigate the proteolytic breakdown of this protein in heart tissue postmortem. If our hypothesis is correct, cTnI might show a distinctive temporal degradation profile after death. This temporal profile may have potential as a time of death marker in forensic medicine. The field of time of death markers has lagged behind the great advances in technology since the late 1850's. Today medical examiners are using rudimentary time of death markers that offer limited reliability in the medico-legal arena. Cardiac TnI must be stabilized in order to avoid further degradation by proteases in the extraction process. Chemically derivatized magnetic microparticles were covalently linked to anti-cTnI monoclonal antibodies. A charge capture approach was also used to eliminate the antibody from the magnetic microparticles given the negative charge on the microparticles. The magnetic microparticles were used to extract cTnI from heart tissue homogenate for further bio-analysis. Cardiac TnI was eluted from the beads with a buffer and analyzed. This technique exploits banding pattern on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by a western blot transfer to polyvinylidene fluoride (PVDF) paper for probing with anti-cTnI monoclonal antibodies. Bovine hearts were used as a model to establish the relationship of time of death and concentration/band-pattern given its homology to human cardiac TnI. The final concept feasibility was tested with human heart samples from cadavers with known time of death. ^

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The investigations of human mitochondrial DNA (mtDNA) have considerably contributed to human evolution and migration. The Middle East is considered to be an essential geographic area for human migrations out of Africa since it is located at the crossroads of Africa, and the rest of the world. United Arab Emirates (UAE) population inhabits the eastern part of Arabian Peninsula and was investigated in this study. Published data of 18 populations were included in the statistical analysis. The diversity indices showed (1) high genetic distance among African populations and (2) high genetic distance between African populations and non-African populations. Asian populations clustered together in the NJ tree between the African and European populations. MtDNA haplotypes database of the UAE population was generated. By incorporating UAE mtDNA dataset into the existing worldwide mtDNA database, UAE Forensic Laboratories will be able to analyze future mtDNA evidence in a more significant and consistent manner. ^

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An alternating treatment design was used to compare the effects of three student response conditions (Clicking, Repeating, and Listening) during computer-assisted instruction on social-studies facts learning and maintenance. Results showed that all students learned and maintained more social-studies facts taught in the Repeating condition followed by the Clicking condition.

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This literature review explores how educators might address adult math anxiety. Curricular, instructional, and non-instructional strategies are reviewed. The suggested approaches emphasize treating the cognitive and physical manifestations of math anxiety.

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Electronic Perception Technology (EPT) enables automated equipment to gain artificial sight commonly referred to as "machine-vision” by employing specialty software and embedded sensors to create a “Visual" input field that can be used as a front-end application for transactional behavior. The authors review this new technology and present feasible future applications to the food service industry in enhancing guest services while providing a competitive advantage.

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In 2010, the American Association of State Highway and Transportation Officials (AASHTO) released a safety analysis software system known as SafetyAnalyst. SafetyAnalyst implements the empirical Bayes (EB) method, which requires the use of Safety Performance Functions (SPFs). The system is equipped with a set of national default SPFs, and the software calibrates the default SPFs to represent the agency's safety performance. However, it is recommended that agencies generate agency-specific SPFs whenever possible. Many investigators support the view that the agency-specific SPFs represent the agency data better than the national default SPFs calibrated to agency data. Furthermore, it is believed that the crash trends in Florida are different from the states whose data were used to develop the national default SPFs. In this dissertation, Florida-specific SPFs were developed using the 2008 Roadway Characteristics Inventory (RCI) data and crash and traffic data from 2007-2010 for both total and fatal and injury (FI) crashes. The data were randomly divided into two sets, one for calibration (70% of the data) and another for validation (30% of the data). The negative binomial (NB) model was used to develop the Florida-specific SPFs for each of the subtypes of roadway segments, intersections and ramps, using the calibration data. Statistical goodness-of-fit tests were performed on the calibrated models, which were then validated using the validation data set. The results were compared in order to assess the transferability of the Florida-specific SPF models. The default SafetyAnalyst SPFs were calibrated to Florida data by adjusting the national default SPFs with local calibration factors. The performance of the Florida-specific SPFs and SafetyAnalyst default SPFs calibrated to Florida data were then compared using a number of methods, including visual plots and statistical goodness-of-fit tests. The plots of SPFs against the observed crash data were used to compare the prediction performance of the two models. Three goodness-of-fit tests, represented by the mean absolute deviance (MAD), the mean square prediction error (MSPE), and Freeman-Tukey R2 (R2FT), were also used for comparison in order to identify the better-fitting model. The results showed that Florida-specific SPFs yielded better prediction performance than the national default SPFs calibrated to Florida data. The performance of Florida-specific SPFs was further compared with that of the full SPFs, which include both traffic and geometric variables, in two major applications of SPFs, i.e., crash prediction and identification of high crash locations. The results showed that both SPF models yielded very similar performance in both applications. These empirical results support the use of the flow-only SPF models adopted in SafetyAnalyst, which require much less effort to develop compared to full SPFs.

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The purpose of this study was to compare the effects of three student response conditions during computer-assisted instruction on the acquisition and maintenance of social-studies facts. Two of the conditions required active student responding (ASR), whereas the other required an on-task (OT) response. Participants were five fifth-grade students, with learning disabilities enrolled in a private school. An alternating treatments design with a best treatments phase was used to compare the effects of the response procedures on three major dependent measures: same-day tests, next-day tests, and maintenance tests. ^ Each week for six weeks, participants were provided daily one-to-one instruction on sets of 21 unknown social-studies facts using a hypermedia computer program, with a new set of facts being practiced each week. Each set of 21 facts was divided randomly into three conditions: Clicking-ASR, Repeating-ASR, and Listening-OT. Hypermedia lesson began weekly with the concept introduction lesson, followed by practice and testing. Practice and testing occurred four days per week, per set. During Clicking-ASR, student practice involved the selection of a social-studies response by clicking on an item with the mouse on the hypermedia card. Repeating-ASR instruction required students to orally repeat the social-studies facts when prompted by the computer. During Listening-OT, students listened to the social-studies facts being read by the computer. During weeks seven and eight, instruction occurred with seven unknown facts using only the best treatment. ^ Test results show that all for all 5 students, the Repeating-ASR practice procedure resulted in more social-studies facts stated correctly on same-day tests, next-day tests, and one-and two-week maintenance tests. Clicking-ASR was the next most effective procedure. During the seventh and eighth week of instruction when only the best practice condition was implemented, Repeating-ASR produced higher scores than all conditions (including Repeating-ASR) during the first six weeks of the study. ^ The results lend further support to the growing body of literature that demonstrates the positive relation between ASR and student achievement. Much of the ASR literature has focused on the effects of increased ASR during teacher-led or peer-mediated instruction. This study adds a dimension to that research in that it demonstrated the importance of ASR during computer-assisted instruction and further suggests that the type of ASR used during computer-assisted instruction may influence learning. Future research is needed to investigate the effectiveness of other types of ASR during computer-assisted instruction and to identify other fundamental characteristics of an effective computer-assisted instruction. ^

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The enzyme S-adenosyl-L-homocysteine (AdoHcy) hydrolase effects hydrolytic cleavage of AdoHcy to adenosine (Ado) and L-homocysteine (Hcy). The cellular levels of AdoHcy and Hcy are critical because AdoHcy is a potent feedback inhibitor of crucial transmethylation enzymes. Also, elevated plasma levels of Hcy in humans have been shown to be a risk factor in coronary artery disease. ^ On the basis of the previous finding that AdoHcy hydrolase is able to add the enzyme-sequestered water molecule across the 5',6'-double bond of (halo or dihalohomovinyl)-adenosines causing covalent binding inhibition, we designed and synthesized AdoHcy analogues with the 5',6'-olefin motif incorporated in place of the carbon-5' and sulfur atoms. From the available synthetic methods we chose two independent approaches: the first approach was based on the construction of a new C5'-C6' double bond via metathesis reactions, and the second approach was based on the formation of a new C6'-C7' single bond via Pd-catalyzed cross-couplings. Cross-metathesis of the suitably protected 5'-deoxy-5'-methyleneadenosine with racemic 2-amino-5-hexenoate in the presence of Hoveyda-Grubb's catalyst followed by standard deprotection afforded the desired analogue as 5' E isomer of the inseparable mixture of 9'R/S diastereomers. Metathesis of chiral homoallylglycine [(2S)-amino-5-hexenoate] produced AdoHcy analogue with established stereochemistry E at C5'atom and S at C9' atom. The 5'-bromovinyl analogue was synthesized using the bromination-dehydrobromination strategy with pyridinium tribromide and DBU. ^ Since literature reports on the Pd-catalyzed monoalkylation of dihaloalkenes (Csp2-Csp3 coupling) were scarce, we were prompted to undertake model studies on Pd-catalyzed coupling between vinyl dihalides and alkyl organometallics. The 1-fluoro-1-haloalkenes were found to undergo Negishi couplings with alkylzinc bromides to give multisubstituted fluoroalkenes. The alkylation was trans-selective affording pure Z-fluoroalkenes. The highest yields were obtained with PdCl 2(dppb) catalyst, but the best stereochemical outcome was obtained with less reactive Pd(PPh3)4. Couplings of 1,1-dichloro-and 1,1-dibromoalkenes with organozinc reagents resulted in the formation of monocoupled 1-halovinyl product. ^

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The purpose of this thesis was to explore the boundary between human and other created by virtual worlds in contemporary science fiction novels. After a close reading of the three novels: Surface Detail, Existence, and Lady of Mazes, and the application of contemporary literary theories, the boundary presented itself and led to the discovery of where the human becomes other. The human becomes other when it becomes lost to the virtual world and no longer exists or interacts with material reality. Each of the primary texts exhibits both virtual reality and humanity in different ways, and each is explored to find where humanity falls apart. Overall, when these theories are applied to real life there is no real way to avoid the potential for fully immersive virtual worlds, but there are ways to avoid their alienating effects.

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This dissertation studies the manipulation of particles using acoustic stimulation for applications in microfluidics and templating of devices. The term particle is used here to denote any solid, liquid or gaseous material that has properties, which are distinct from the fluid in which it is suspended. Manipulation means to take over the movements of the particles and to position them in specified locations. Using devices, microfabricated out of silicon, the behavior of particles under the acoustic stimulation was studied with the main purpose of aligning the particles at either low-pressure zones, known as the nodes or high-pressure zones, known as anti-nodes. By aligning particles at the nodes in a flow system, these particles can be focused at the center or walls of a microchannel in order to ultimately separate them. These separations are of high scientific importance, especially in the biomedical domain, since acoustopheresis provides a unique approach to separate based on density and compressibility, unparalleled by other techniques. The study of controlling and aligning the particles in various geometries and configurations was successfully achieved by controlling the acoustic waves. Apart from their use in flow systems, a stationary suspended-particle device was developed to provide controllable light transmittance based on acoustic stimuli. Using a glass compartment and a carbon-particle suspension in an organic solvent, the device responded to acoustic stimulation by aligning the particles. The alignment of light-absorbing carbon particles afforded an increase in visible light transmittance as high as 84.5%, and it was controlled by adjusting the frequency and amplitude of the acoustic wave. The device also demonstrated alignment memory rendering it energy-efficient. A similar device for suspended-particles in a monomer enabled the development of electrically conductive films. These films were based on networks of conductive particles. Elastomers doped with conductive metal particles were rendered surface conductive at particle loadings as low as 1% by weight using acoustic focusing. The resulting films were flexible and had transparencies exceeding 80% in the visible spectrum (400-800 nm) These films had electrical bulk conductivities exceeding 50 S/cm.

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This dissertation established a state-of-the-art programming tool for designing and training artificial neural networks (ANNs) and showed its applicability to brain research. The developed tool, called NeuralStudio, allows users without programming skills to conduct studies based on ANNs in a powerful and very user friendly interface. A series of unique features has been implemented in NeuralStudio, such as ROC analysis, cross-validation, network averaging, topology optimization, and optimization of the activation function’s slopes. It also included a Support Vector Machines module for comparison purposes. Once the tool was fully developed, it was applied to two studies in brain research. In the first study, the goal was to create and train an ANN to detect epileptic seizures from subdural EEG. This analysis involved extracting features from the spectral power in the gamma frequencies. In the second application, a unique method was devised to link EEG recordings to epileptic and non-epileptic subjects. The contribution of this method consisted of developing a descriptor matrix that can be used to represent any EEG file regarding its duration and the number of electrodes. The first study showed that the inter-electrode mean of the spectral power in the gamma frequencies and its duration above a specific threshold performs better than the other frequencies in seizure detection, exhibiting an accuracy of 95.90%, a sensitivity of 92.59%, and a specificity of 96.84%. The second study yielded that Hjorth’s parameter activity is sufficient to accurately relate EEG to epileptic and non-epileptic subjects. After testing, accuracy, sensitivity and specificity of the classifier were all above 0.9667. Statistical tests measured the superiority of activity at over 99.99 % certainty. It was demonstrated that 1) the spectral power in the gamma frequencies is highly effective in locating seizures from EEG and 2) activity can be used to link EEG recordings to epileptic and non-epileptic subjects. These two studies required high computational load and could be addressed thanks to NeuralStudio. From a medical perspective, both methods proved the merits of NeuralStudio in brain research applications. For its outstanding features, NeuralStudio has been recently awarded a patent (US patent No. 7502763).

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The enzyme S-adenosyl-L-homocysteine (AdoHey) hydrolase effects hydrolytic cleavage of AdoHcy to adenosine (Ado) and L-homocysteine (Hcy). The cellular levels of AdoHcy and Hcy are critical because AdoHcy is a potent feedback inhibitor of crucial transmethylation enzymes. Also, elevated plasma levels of Hcy in humans have been shown to be a risk factor in coronary artery disease. On the basis of the previous finding that AdoHcy hydrolase is able to add the enzyme-sequestered water molecule across the 5',6'-double bond of (halo or dihalohomovinyl)-adenosines causing covalent binding inhibition, we designed and synthesized AdoHcy analogues with the 5',6'-olefin motif incorporated in place of the carbon-5' and sulfur atoms. From the available synthetic methods we chose two independent approaches: the first approach was based on the construction of a new C5'- C6' double bond via metathesis reactions, and the second approach was based on the formation of a new C6'-C7' single bond via Pd-catalyzed cross-couplings. Cross-metathesis of the suitably protected 5'-deoxy-5'-methyleneadenosine with racemic 2-amino-5-hexenoate in the presence of Hoveyda-Grubb's catalyst followed by standard deprotection afforded the desired analogue as 5'E isomer of the inseparable mixture of 9'RIS diastereomers. Metathesis of chiral homoallylglycine [(2S)-amino-5-hexenoate] produced AdoHcy analogue with established stereochemistry E at C5'atom and S at C9' atom. The 5'-bromovinyl analogue was synthesized using the brominationdehydrobromination strategy with pyridinium tribromide and DBU. Since literature reports on the Pd-catalyzed monoalkylation of dihaloalkenes (Csp2-Csp3 coupling) were scarce, we were prompted to undertake model studies on Pdcatalyzed coupling between vinyl dihalides and alkyl organometallics. The 1-fluoro-1- haloalkenes were found to undergo Negishi couplings with alkylzinc bromides to give multisubstituted fluoroalkenes. The alkylation was trans-selective affording pure Zfluoroalkenes. The highest yields were obtained with PdCl 2(dppb) catalyst, but the best stereochemical outcome was obtained with less reactive Pd(PPh3)4 . Couplings of 1,1- dichloro-and 1,1-dibromoalkenes with organozinc reagents resulted in the formation of monocoupled 1-halovinyl product.

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This study was undertaken to examine how instructor use of emerging technologies can contribute to better quality pre-service teacher education. A group of nine Memorial University Faculty of Education instructors attempted to systematically incorporate mobile tablet (iPad) technologies into their on-campus instruction over the period of one academic year (2013-2014). Participants familiarized themselves with their device; evaluated a range of instructional applications (apps) specific to their discipline and/or teaching focus areas; and attempted to intentionally integrate the device into the classroom-learning environment. The research team utilized several focus groups and semi-structured interviews to elicit the representations of participants with respect to their impressions of the value of tablet technologies and their experiences in implementing tablet technology in their instructional practice.

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