Search results for: performance level.
7855 Multitasking Trends and Impact on Education: A Literature Review
Authors: Mohammed Alkahtani, Ali Ahmad, Saber Darmoul, Shatha Samman, Ayoub Al-zabidi, Khaled Ba Matraf
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Education systems are complex and involve interactions between humans (teachers and students); media based technologies, lectures, classrooms, etc. to provide educational services. The education system performance is characterized by how well students learn, which is measured using student grades on exams and quizzes, achievements on standardized tests, among others. Advances in portable communications technologies, such as mobile phones, tablets, and laptops, created a different type of classroom, where students seem to engage in more than just the intended learning activities. The performance of more than one task in parallel or in rapid transition is commonly known as multitasking. Several operations in educational systems are performed simultaneously, resulting in a multitasking education environment. This paper surveys existing research on multitasking in educational settings, summarizes literature findings, provides a synthesis of the impact of multitasking on performance, and identifies directions of future research.
Keywords: Education systems, GPA, multitasking, performance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 60527854 Efficient Alias-free Level Crossing Sampling
Authors: Negar Riazifar, Nigel G. Stocks
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This paper proposes strategies in level crossing (LC) sampling and reconstruction that provide alias-free high-fidelity signal reconstruction for speech signals without exponentially increasing sample number with increasing bit-depth. We introduce methods in LC sampling that reduce the sampling rate close to the Nyquist frequency even for large bit-depth. The results indicate that larger variation in the sampling intervals leads to alias-free sampling scheme; this is achieved by either reducing the bit-depth or adding a jitter to the system for high bit-depths. In conjunction with windowing, the signal is reconstructed from the LC samples using an efficient Toeplitz reconstruction algorithm.
Keywords: Alias-free, level crossing sampling, spectrum, trigonometric polynomial.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3167853 Dynamic Visualization on Student's Performance, Retention and Transfer of Procedural Learning
Authors: Fauzy M. Wan, Reem S.A. Baragash
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This study examined the effects of two dynamic visualizations on 60 Malaysian primary school student-s performance (time on task), retention and transference. The independent variables in this study were the two dynamic visualizations, the video and the animated instructions. The dependent variables were the gain score of performance, retention and transference. The results showed that the students in the animation group significantly outperformed the students in the video group in retention. There were no significant differences in terms of gain scores in the performance and transference among the animation and the video groups, although the scores were slightly higher in the animation group compared to the video group. The conclusion of this study is that the animation visualization is superior compared to the video in the retention for a procedural task.Keywords: Dynamic visualization, Procedural Task, Retention, Transference
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14297852 Effects of Length of Time of Fasting upon Subjective and Objective Variables When Controlling Sleep, Food and Fluid Intakes
Authors: H. Alabed, K. Abuzayan. L. Fgie, K. Zarug
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Ramadan requires individuals to abstain from food and fluid intake between sunrise and sunset; physiological considerations predict that poorer mood, physical performance and mental performance will result. In addition, any difficulties will be worsened because preparations for fasting and recovery from it often mean that nocturnal sleep is decreased in length, and this independently affects mood and performance.
A difficulty of interpretation in many studies is that the observed changes could be due to fasting but also to the decreased length of sleep and altered food and fluid intakes before and after the daytime fasting. These factors were separated in this study, which took place over three separate days and compared the effects of different durations of fasting (4, 8 or 16h) upon a wide variety of measures (including subjective and objective assessments of performance, body composition, dehydration and responses to a short bout of exercise) - but with an unchanged amount of nocturnal sleep, controlled supper the previous evening, controlled intakes at breakfast and daytime naps not being allowed. Many of the negative effects of fasting observed in previous studies were present in this experiment also. These findings indicate that fasting was responsible for many of the changes previously observed, though some effect of sleep loss, particularly if occurring on successive days (as would occur in Ramadan) cannot be excluded.
Keywords: Drinking, Eating, Mental Performance, Physical Performance, Social Activity, Blood, Sleepiness.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16507851 Exploring SSD Suitable Allocation Schemes Incompliance with Workload Patterns
Authors: Jae Young Park, Hwansu Jung, Jong Tae Kim
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In the Solid-State-Drive (SSD) performance, whether the data has been well parallelized is an important factor. SSD parallelization is affected by allocation scheme and it is directly connected to SSD performance. There are dynamic allocation and static allocation in representative allocation schemes. Dynamic allocation is more adaptive in exploiting write operation parallelism, while static allocation is better in read operation parallelism. Therefore, it is hard to select the appropriate allocation scheme when the workload is mixed read and write operations. We simulated conditions on a few mixed data patterns and analyzed the results to help the right choice for better performance. As the results, if data arrival interval is long enough prior operations to be finished and continuous read intensive data environment static allocation is more suitable. Dynamic allocation performs the best on write performance and random data patterns.
Keywords: Dynamic allocation, NAND Flash based SSD, SSD parallelism, static allocation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19947850 Experimental Study of Performance of a Counter Flow Ranque-Hilsch Vortex Tube with Inner Threaded Body
Authors: Gürol Önal, Kevser Dincer
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In this experimental study, performance of a counter flow Ranque-Hilsch vortex tube (RHVT) with threads cut on its inner surface was investigated experimentally (pitch is 1 and 2 mm). The inner diameter of the vortex tube used was D=9 mm and the ratio of the tube’s length to diameter was L/D=12. The experimental system was a thermodynamic open system. Flow was controlled by a valve on the hot outlet side, where the valve was changed from a nearly closed position to its nearly open position. Fraction of cold flow (ξ) = 0.1-0.9, was determined under 300 and 350 kPa pressurized air. All experimental data were compared with each other, the maximum heating performance of the RHVT system was found to be 38.2 oC and the maximum cooling performance of the RHVT in this study was found to be -30.9 oC at pitch 1 mm.
Keywords: Ranque-Hilsch vortex tube, heating, cooling, temperature separation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 28717849 M2LGP: Mining Multiple Level Gradual Patterns
Authors: Yogi Satrya Aryadinata, Anne Laurent, Michel Sala
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Gradual patterns have been studied for many years as they contain precious information. They have been integrated in many expert systems and rule-based systems, for instance to reason on knowledge such as “the greater the number of turns, the greater the number of car crashes”. In many cases, this knowledge has been considered as a rule “the greater the number of turns → the greater the number of car crashes” Historically, works have thus been focused on the representation of such rules, studying how implication could be defined, especially fuzzy implication. These rules were defined by experts who were in charge to describe the systems they were working on in order to turn them to operate automatically. More recently, approaches have been proposed in order to mine databases for automatically discovering such knowledge. Several approaches have been studied, the main scientific topics being: how to determine what is an relevant gradual pattern, and how to discover them as efficiently as possible (in terms of both memory and CPU usage). However, in some cases, end-users are not interested in raw level knowledge, and are rather interested in trends. Moreover, it may be the case that no relevant pattern can be discovered at a low level of granularity (e.g. city), whereas some can be discovered at a higher level (e.g. county). In this paper, we thus extend gradual pattern approaches in order to consider multiple level gradual patterns. For this purpose, we consider two aggregation policies, namely horizontal and vertical.Keywords: Gradual Pattern.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15007848 A Development of Online Lessons to Strengthen the Learning Process of Master's Degree Students Majoring in Curriculum and Instruction at Suan Sunandha Rajabhat University
Authors: Chaiwat Waree
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The purposes of the research were to develop online lessons to strengthen the learning process of Master's degree students majoring in Curriculum and Instruction at Suan Sunandha Rajabhat University; to achieve the efficiency criteria of 80/80; and to study the satisfaction of students who use online lessons to strengthen the learning process of Master’s degree students majoring in Curriculum and Instruction at Suan Sunandha Rajabhat University. The sample consisted of 40 university students studying in semester 1, academic year 2012. The sample was determined by Purposive Sampling. Selected students were from the class which the researcher was the homeroom tutor. The tutor was responsible for the teaching of learning process. Tools used in the study were online lessons, 60-point performance test, and evaluation test of satisfaction of students on online lessons. Data analysis yielded the following results; 83.66/88.29 efficiency of online lessons measured against the criteria; the comparison of performance before and after taking online lessons using t-test yielded 29.67. The statistical significance was at 0.05; the average satisfaction level of forty students on online lessons was 4.46 with standard deviation of 0.68.
Keywords: Online Lessons, Curriculum and Instruction.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14347847 Investigation of Monochromatization Light Effect at Molecular/Atomic Level in Electronegative-Electropositive Gas Mixtures Plasma
Authors: L.C. Ciobotaru
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In electronegative-electropositive gas mixtures plasma, at a total pressure varying in the range of ten to hundred Torr, the appearance of a quasi-mochromatization effect of the emitted radiation was reported. This radiation could be the result of the generating mechanisms at molecular level, which is the case of the excimer radiation but also at atomic level. Thus, in the last case, in (Ne+1%Ar/Xe+H2) gas mixtures plasma in a dielectric barrier discharge, this effect, called M-effect, consists in the reduction of the discharge emission spectrum practice at one single, strong spectral line with λ = 585.3 nm. The present paper is concerned with the characteristics comparative investigation of the principal reaction mechanisms involved in the quasi-monochromatization effect existence in the case of the excimer radiation, respectively of the Meffect. Also, the paper points out the role of the metastable electronegative atoms in the appearance of the monochromatization – effect at atomic level.
Keywords: Colombian forces, Direct Harpoon reaction, Monochromatization – effect, Resonant polar three-body reaction.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14077846 Enhancing the Error-Correcting Performance of LDPC Codes through an Efficient Use of Decoding Iterations
Authors: Insah Bhurtah, P. Clarel Catherine, K. M. Sunjiv Soyjaudah
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The decoding of Low-Density Parity-Check (LDPC) codes is operated over a redundant structure known as the bipartite graph, meaning that the full set of bit nodes is not absolutely necessary for decoder convergence. In 2008, Soyjaudah and Catherine designed a recovery algorithm for LDPC codes based on this assumption and showed that the error-correcting performance of their codes outperformed conventional LDPC Codes. In this work, the use of the recovery algorithm is further explored to test the performance of LDPC codes while the number of iterations is progressively increased. For experiments conducted with small blocklengths of up to 800 bits and number of iterations of up to 2000, the results interestingly demonstrate that contrary to conventional wisdom, the error-correcting performance keeps increasing with increasing number of iterations.
Keywords: Error-correcting codes, information theory, low-density parity-check codes, sum-product algorithm.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17087845 The Influence of RHA on the Mechanical Properties of Mortar Heated Up To High Temperature
Authors: Md. Harunur Rashid, S. M. Kamal Uddin, Sobura khatun
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The performance of mortar subjected to high temperature and cooled in normal ambient temperature was examined in the laboratory to comply with the situation of burning & cooling of a structure. Four series of cubical (5 X 5 X 5 cm) mortar specimens were made from OPC, and partial replacement (10, 15, 20, 25 & 30%) of OPC by Rice Husk Ash (RHA) produced in the uncontrolled environment. These specimens were heated in electric furnace to 200, 300, 400, 500 and 7000C. The specimens were kept in normal room temperature for cooling. They were then tested for mechanical properties and the results shows that particular 20% RHA mixed mortar shows better fire performance.Keywords: Fire performance, Rice Husk
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15647844 Utilizing the Analytic Hierarchy Process in Improving Performances of Blind Judo
Authors: Hyun Chul Cho, Hyunkyoung Oh, Hyun Yoon, Jooyeon Jin, Jae Won Lee
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Identifying, structuring, and racking the most important factors related to improving athletes’ performances could pave the way for improve training system. The purpose of this study was to identify the relative importance factors to improve performance of the of judo athletes with visual impairments, including blindness by using the Analytic Hierarchy Process (AHP). After reviewing the literature, the relative importance of factors affecting performance of the blind judo was selected. A group of expert reviewed the first draft of the questionnaires, and then finally selected performance factors were classified into the major categories of techniques, physical fitness, and psychological categories. Later, a pre-selected experts group was asked to review the final version of questionnaire and confirm the priories of performance factors. The order of priority was determined by performing pairwise comparisons using Expert Choice 2000. Results indicated that “grappling” (.303) and “throwing” (.234) were the most important lower hierarchy factors for blind judo skills. In addition, the most important physical factors affecting performance were “muscular strength and endurance” (.238). Further, among other psychological factors “competitive anxiety” (.393) was important factor that affects performance. It is important to offer psychological skills training to reduce anxiety of judo athletes with visual impairments and blindness, so they can compete in their optimal states. These findings offer insights into what should be considered when determining factors to improve performance of judo athletes with visual impairments and blindness.
Keywords: Analytic hierarchy process, blind athlete, judo, sport performance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 8017843 An Approach to Manage and Evaluate Asset Performance
Authors: Mohammed S. ALSaidi, John P. Mo
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Modern engineering assets are complex and very high in value. They are expected to function for years to come, with ability to handle the change in technology and ageing modification. The aging of an engineering asset and continues increase of vendors and contractors numbers forces the asset operation management (or Owner) to design an asset system which can capture these changes. Furthermore, an accurate performance measurement and risk evaluation processes are highly needed. Therefore, this paper explores the nature of the asset management system performance evaluation for an engineering asset based on the System Support Engineering (SSE) principles. The research work explores the asset support system from a range of perspectives, interviewing managers from across a refinery organization. The factors contributing to complexity of an asset management system are described in context which clusters them into several key areas. It is proposed that SSE framework may then be used as a tool for analysis and management of asset. The paper will conclude with discussion of potential application of the framework and opportunities for future research.
Keywords: Asset management, performance, evaluation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23587842 CEO Duality and Firm Performance: An Integration of Institutional Perceptive with Agency Theory
Authors: A. Ujunwa, P. O. Salami, A. H. Umar
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The recommendation of the committee on corporate governance for public companies in Nigeria, that the position of the CEO be separated from board chair has generated serious debate among scholars and practitioners. They have questioned the appropriateness of implementing corporate governance model that is based on Anglo-Saxon agency problem characterized by dispersed ownership structure; where markets for corporate control, legal regulation, and contractual incentives are the key governance mechanisms. This paper strives to resolve the argument by adopting an institutional perspective in testing the agency theory on board duality. The study developed a theoretical and empirical model to better understand how ownership structure influences agency conflict and how such affects firm performance. Hence, the study examines the relationship between CEO duality and firm performance using two institutional ownership structures – dispersed ownership and concentrated ownership structures. The empirical results show that CEO duality is negatively correlated with firm performance in Nigeria irrespective of the firm-s ownership structure. The findings give credence to the recommendation of the Peterside Commission on the need to separate the position of CEO from board chair.Keywords: Corporate Governance, CEO-Duality, Firm Performance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 39797841 Medical Image Segmentation Using Deformable Models and Local Fitting Binary
Authors: B. Bagheri Nakhjavanlo, T. J. Ellis, P. Raoofi, J. Dehmeshki
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This paper presents a customized deformable model for the segmentation of abdominal and thoracic aortic aneurysms in CTA datasets. An important challenge in reliably detecting aortic aneurysm is the need to overcome problems associated with intensity inhomogeneities and image noise. Level sets are part of an important class of methods that utilize partial differential equations (PDEs) and have been extensively applied in image segmentation. A Gaussian kernel function in the level set formulation, which extracts the local intensity information, aids the suppression of noise in the extracted regions of interest and then guides the motion of the evolving contour for the detection of weak boundaries. The speed of curve evolution has been significantly improved with a resulting decrease in segmentation time compared with previous implementations of level sets. The results indicate the method is more effective than other approaches in coping with intensity inhomogeneities.Keywords: Abdominal and thoracic aortic aneurysms, intensityinhomogeneity, level sets, local fitting binary.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18167840 Linear Prediction System in Measuring Glucose Level in Blood
Authors: Intan Maisarah Abd Rahim, Herlina Abdul Rahim, Rashidah Ghazali
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Diabetes is a medical condition that can lead to various diseases such as stroke, heart disease, blindness and obesity. In clinical practice, the concern of the diabetic patients towards the blood glucose examination is rather alarming as some of the individual describing it as something painful with pinprick and pinch. As for some patient with high level of glucose level, pricking the fingers multiple times a day with the conventional glucose meter for close monitoring can be tiresome, time consuming and painful. With these concerns, several non-invasive techniques were used by researchers in measuring the glucose level in blood, including ultrasonic sensor implementation, multisensory systems, absorbance of transmittance, bio-impedance, voltage intensity, and thermography. This paper is discussing the application of the near-infrared (NIR) spectroscopy as a non-invasive method in measuring the glucose level and the implementation of the linear system identification model in predicting the output data for the NIR measurement. In this study, the wavelengths considered are at the 1450 nm and 1950 nm. Both of these wavelengths showed the most reliable information on the glucose presence in blood. Then, the linear Autoregressive Moving Average Exogenous model (ARMAX) model with both un-regularized and regularized methods was implemented in predicting the output result for the NIR measurement in order to investigate the practicality of the linear system in this study. However, the result showed only 50.11% accuracy obtained from the system which is far from the satisfying results that should be obtained.
Keywords: Diabetes, glucose level, linear, near-infrared (NIR), non-invasive, prediction system.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 8757839 Coverage and Capacity Performance Degradation on a Co-Located Network Involving CDMA2000 and WCDMA @1.9GH
Authors: O. C. Nosiri, V. E. Idigo, C. O. Ohaneme, K. A. Akpado
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Coverage and capacity performance in a cellular network determines the system potentials. If the coverage radius is limited, end users suffer poor service quality, if the system capacity reduces, fewer subscribers will be accommodated. This paper investigated the performance effects of the noise rise caused by the spurious emission from a co-located jammer involving downlink frequency of CDMA2000 and uplink frequency of WCDMA operating at 1.9GHz. Measurements were carried out to evaluate the impact on the coverage radius and the system capacity.
Keywords: Capacity, Co-location, Coverage, Noise rise.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19757838 Design and Implementation of Shared Memory based Parallel File System Logging Method for High Performance Computing
Authors: Hyeyoung Cho, Sungho Kim, SangDong Lee
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I/O workload is a critical and important factor to analyze I/O pattern and file system performance. However tracing I/O operations on the fly distributed parallel file system is non-trivial due to collection overhead and a large volume of data. In this paper, we design and implement a parallel file system logging method for high performance computing using shared memory-based multi-layer scheme. It minimizes the overhead with reduced logging operation response time and provides efficient post-processing scheme through shared memory. Separated logging server can collect sequential logs from multiple clients in a cluster through packet communication. Implementation and evaluation result shows low overhead and high scalability of this architecture for high performance parallel logging analysis.Keywords: I/O workload, PVFS, I/O Trace.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15607837 Energy Communities from Municipality Level to Province Level: A Comparison Using Autoregressive Integrated Moving Average Model
Authors: Amro Issam Hamed Attia Ramadan, Marco Zappatore, Pasquale Balena, Antonella Longo
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Considering the energy crisis that is hitting Europe, it becomes increasingly necessary to change energy policies to depend less on fossil fuels and replace them with energy from renewable sources. This has triggered the urge to use clean energy, not only to satisfy energy needs and fulfill the required consumption, but also to decrease the danger of climatic changes due to harmful emissions. Many countries have already started creating energy communities based on renewable energy sources. The first step to understanding energy needs in any place is to perfectly know the consumption. In this work, we aim to estimate electricity consumption for a municipality that makes up part of a rural area located in southern Italy using forecast models that allow for the estimation of electricity consumption for the next 10 years, and we then apply the same model to the province where the municipality is located and estimate the future consumption for the same period to examine whether it is possible to start from the municipality level to reach the province level when creating energy communities.
Keywords: ARIMA, electricity consumption, forecasting models, time series.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2827836 Performance Analysis of a WiMax/Wi-Fi System Whilst Streaming a Video Conference Application
Authors: Patrice Obinna Umenne, Marcel O. Odhiambo
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WiMAX and Wi-Fi are considered as the promising broadband access solutions for wireless MAN’s and LANs, respectively. In the recent works WiMAX is considered suitable as a backhaul service to connect multiple dispersed Wi-Fi ‘hotspots’. Hence a new integrated WiMAX/Wi-Fi architecture has been proposed in literatures. In this paper the performance of an integrated WiMAX/Wi-Fi network has been investigated by streaming a video conference application. The difference in performance between the two protocols is compared with respect to video conferencing. The Heterogeneous network was simulated in the OPNET simulator.
Keywords: Throughput, delay, delay variance, packet loss, Quality of Service (QoS).
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26497835 Modelling a Hospital as a Queueing Network: Analysis for Improving Performance
Authors: Emad Alenany, M. Adel El-Baz
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In this paper, the flow of different classes of patients into a hospital is modelled and analyzed by using the queueing network analyzer (QNA) algorithm and discrete event simulation. Input data for QNA are the rate and variability parameters of the arrival and service times in addition to the number of servers in each facility. Patient flows mostly match real flow for a hospital in Egypt. Based on the analysis of the waiting times, two approaches are suggested for improving performance: Separating patients into service groups, and adopting different service policies for sequencing patients through hospital units. The separation of a specific group of patients, with higher performance target, to be served separately from the rest of patients requiring lower performance target, requires the same capacity while improves performance for the selected group of patients with higher target. Besides, it is shown that adopting the shortest processing time and shortest remaining processing time service policies among other tested policies would results in, respectively, 11.47% and 13.75% reduction in average waiting time relative to first come first served policy.Keywords: Queueing network, discrete-event simulation, health applications, SPT.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15297834 Performance Comparison of a Low Cost Air Quality Sensor with a Commercial Electronic Nose
Authors: Ünal Kızıl, Levent Genç, Sefa Aksu, Ahmet Tapınç
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The Figaro AM-1 sensor module which employs TGS 2600 model gas sensor in air quality assessment was used. The system was coupled with a microprocessor that enables sensor module to create warning message via telephone. This low cot sensor system’s performance was compared with a DiagNose II commercial electronic nose system. Both air quality sensor and electronic nose system employ metal oxide chemical gas sensors. In the study experimental setup, data acquisition methods for electronic nose system, and performance of the low cost air quality system were evaluated and explained.Keywords: Air quality, electronic nose, environmental quality, gas sensor.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23867833 A Third Drop Level For TCP-RED Congestion Control Strategy
Authors: Nabhan Hamadneh, Michael Dixon, Peter Cole, David Murray
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This work presents the Risk Threshold RED (RTRED) congestion control strategy for TCP networks. In addition to the maximum and minimum thresholds in existing RED-based strategies, we add a third dropping level. This new dropping level is the risk threshold which works with the actual and average queue sizes to detect the immediate congestion in gateways. Congestion reaction by RTRED is on time. The reaction to congestion is neither too early, to avoid unfair packet losses, nor too late to avoid packet dropping from time-outs. We compared our novel strategy with RED and ARED strategies for TCP congestion handling using a NS-2 simulation script. We found that the RTRED strategy outperformed RED and ARED.Keywords: AQM, congestion control, RED, TCP.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14937832 Study on Seismic Performance of Reinforced Soil Walls to Modify the Pseudo Static Method
Authors: Majid Yazdandoust
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This study, tries to suggest a design method based on displacement using finite difference numerical modeling in reinforcing soil retaining wall with steel strip. In this case, dynamic loading characteristics such as duration, frequency, peak ground acceleration, geometrical characteristics of reinforced soil structure and type of the site are considered to correct the pseudo static method and finally introduce the pseudo static coefficient as a function of seismic performance level and peak ground acceleration. For this purpose, the influence of dynamic loading characteristics, reinforcement length, height of reinforced system and type of the site are investigated on seismic behavior of reinforcing soil retaining wall with steel strip. Numerical results illustrate that the seismic response of this type of wall is highly dependent to cumulative absolute velocity, maximum acceleration, and height and reinforcement length so that the reinforcement length can be introduced as the main factor in shape of failure. Considering the loading parameters, geometric parameters of the wall and type of the site showed that the used method in this study leads to efficient designs in comparison with other methods, which are usually based on limit-equilibrium concept. The outputs show the over-estimation of equilibrium design methods in comparison with proposed displacement based methods here.Keywords: Pseudo static coefficient, seismic performance design, numerical modeling, steel strip reinforcement, retaining walls, cumulative absolute velocity, failure shape.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21537831 A Face-to-Face Education Support System Capable of Lecture Adaptation and Q&A Assistance Based On Probabilistic Inference
Authors: Yoshitaka Fujiwara, Jun-ichirou Fukushima, Yasunari Maeda
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Keys to high-quality face-to-face education are ensuring flexibility in the way lectures are given, and providing care and responsiveness to learners. This paper describes a face-to-face education support system that is designed to raise the satisfaction of learners and reduce the workload on instructors. This system consists of a lecture adaptation assistance part, which assists instructors in adapting teaching content and strategy, and a Q&A assistance part, which provides learners with answers to their questions. The core component of the former part is a “learning achievement map", which is composed of a Bayesian network (BN). From learners- performance in exercises on relevant past lectures, the lecture adaptation assistance part obtains information required to adapt appropriately the presentation of the next lecture. The core component of the Q&A assistance part is a case base, which accumulates cases consisting of questions expected from learners and answers to them. The Q&A assistance part is a case-based search system equipped with a search index which performs probabilistic inference. A prototype face-to-face education support system has been built, which is intended for the teaching of Java programming, and this approach was evaluated using this system. The expected degree of understanding of each learner for a future lecture was derived from his or her performance in exercises on past lectures, and this expected degree of understanding was used to select one of three adaptation levels. A model for determining the adaptation level most suitable for the individual learner has been identified. An experimental case base was built to examine the search performance of the Q&A assistance part, and it was found that the rate of successfully finding an appropriate case was 56%.
Keywords: Bayesian network, face-to-face education, lecture adaptation, Q&A assistance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 13587830 Electrochemical Performance of Al-Mn2O3 Based Electrode Materials
Authors: Noor Ul Ain Bhatti, M. Junaid Khan, Javed Ahmad, Murtaza Saleem, Shahid M. Ramay, Saadat A. Siddiqi
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Manganese oxide is being recently used as electrode material for rechargeable batteries. In this study, Al incorporated Mn2O3 compositions were synthesized to study the effect of Al doping on electrochemical performance of host material. Structural studies were carried out using X-ray diffraction analysis to confirm the phase stability and explore the lattice parameters, crystallite size, lattice strain, density and cell volume. Morphology and composition were analyzed using field emission scanning electron microscope and energy dispersive X-ray spectroscopy, respectively. Dynamic light scattering analysis was performed to observe the average particle size of the compositions. FTIR measurements exhibit the O-Al-O and O-Mn-O and Al-O bonding and with increasing the concentration of Al, the vibrational peaks of Mn-O become sharper. An enhanced electrochemical performance was observed in compositions with higher Al content.
Keywords: Mn2O3, electrode materials, energy storage and conversion, electrochemical performance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18607829 Featured based Segmentation of Color Textured Images using GLCM and Markov Random Field Model
Authors: Dipti Patra, Mridula J
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In this paper, we propose a new image segmentation approach for colour textured images. The proposed method for image segmentation consists of two stages. In the first stage, textural features using gray level co-occurrence matrix(GLCM) are computed for regions of interest (ROI) considered for each class. ROI acts as ground truth for the classes. Ohta model (I1, I2, I3) is the colour model used for segmentation. Statistical mean feature at certain inter pixel distance (IPD) of I2 component was considered to be the optimized textural feature for further segmentation. In the second stage, the feature matrix obtained is assumed to be the degraded version of the image labels and modeled as Markov Random Field (MRF) model to model the unknown image labels. The labels are estimated through maximum a posteriori (MAP) estimation criterion using ICM algorithm. The performance of the proposed approach is compared with that of the existing schemes, JSEG and another scheme which uses GLCM and MRF in RGB colour space. The proposed method is found to be outperforming the existing ones in terms of segmentation accuracy with acceptable rate of convergence. The results are validated with synthetic and real textured images.
Keywords: Texture Image Segmentation, Gray Level Cooccurrence Matrix, Markov Random Field Model, Ohta colour space, ICM algorithm.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21737828 Performance, Need and Discriminatory Allegiance of Employees as Awarding Criteria of Distributive Justice
Authors: B. Gangloff, L. Mayoral, A. Rezrazi
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Three types of salary distribution are usually proposed by the theorists of distributive justice: Equality, equity and need. Their influence has been studied, taking into consideration (in terms of equity) the performance of the employees and their degree of allegiance/rebellion in what regards discriminatory hierarchical orders, by taking into account the reasons of such allegiance/rebellion (allegiance out of conviction, legalism or opportunism/ethical rebellion). Conducted in Argentina, the study has confronted 480 students (240 male and 240 female) with a practical case in which they had to advise a manager of a real estate agency on the allocation of a bonus amongst his employees. The latter were characterized according to their respective performance, one of them being further defined as being (or not) in a financial need and as having complied (or not) with a discriminatory hierarchical order regarding foreigners. The results show that the distribution of the bonus only follows the rules of equity and need: The employees more efficient, allegiant or in need, are rewarded more than the others. It is also noteworthy that the allegiant employees are rewarded in the same way, regardless of the reason for their allegiance, and that the employee who refuses to adopt a discriminatory conduct is penalized.
Keywords: Distributive justice, equity, performance, allegiance, ethic.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19167827 Performance Evaluation of Al Jame’ Roundabout Using SIDRA
Authors: D. Muley, H. S. Al-Mandhari
Abstract:
This paper evaluates the performance of a multi-lane four legged modern roundabout operating in Muscat using SIDRA model. The performance measures include Degree of Saturation (DOS), average delay, and queue lengths. The geometric and traffic data were used for model preparation. Gap acceptance parameters, critical gap and follow up headway, were used for calibration of SIDRA model. The results from the analysis showed that currently the roundabout is experiencing delays up to 610 seconds per vehicle with DOS 1.67 during peak hour. Further, sensitivity analysis for general and roundabout parameters was performed, amongst lane width, cruise speed, inscribed diameter, entry radius and entry angle showed that inscribed diameter is most crucial factor affecting delay and DOS. Up gradation of roundabout to fully signalized junction was found as the suitable solution which will serve for future years with LOS C for design year having DOS of 0.9 with average control delay of 51.9 seconds per vehicle.
Keywords: Performance analysis, roundabout, sensitivity analysis, SIDRA.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 33067826 Evaluation of Power Factor Corrected AC - DC Converters and Controllers to meet UPS Performance Index
Authors: A. Muthuramalingam, S. Himavathi
Abstract:
Harmonic pollution and low power factor in power systems caused by power converters have been of great concern. To overcome these problems several converter topologies using advanced semiconductor devices and control schemes have been proposed. This investigation is to identify a low cost, small size, efficient and reliable ac to dc converter to meet the input performance index of UPS. The performance of single phase and three phase ac to dc converter along with various control techniques are studied and compared. The half bridge converter topology with linear current control is identified as most suitable. It is simple, energy efficient because of single switch power loss and transformer-less operation of UPS. The results are validated practically using a prototype built using IGBT and analog controller. The performance for both single and three-phase system is verified. Digital implementation of closed loop control achieves higher reliability. Its cost largely depends on chosen bit precision. The minimal bit precision for optimum converter performance is identified as 16-bit with fixed-point operation. From the investigation and practical implementation it is concluded that half bridge ac – dc converter along with digital linear controller meets the performance index of UPS for single and three phase systems.Keywords: PFC, energy efficient, half bridge, ac-dc converter, boost topology, linear current control, digital bit precision.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3035