Search results for: higher harmonic.
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 3199

Search results for: higher harmonic.

1639 Learning User Keystroke Patterns for Authentication

Authors: Ying Zhao

Abstract:

Keystroke authentication is a new access control system to identify legitimate users via their typing behavior. In this paper, machine learning techniques are adapted for keystroke authentication. Seven learning methods are used to build models to differentiate user keystroke patterns. The selected classification methods are Decision Tree, Naive Bayesian, Instance Based Learning, Decision Table, One Rule, Random Tree and K-star. Among these methods, three of them are studied in more details. The results show that machine learning is a feasible alternative for keystroke authentication. Compared to the conventional Nearest Neighbour method in the recent research, learning methods especially Decision Tree can be more accurate. In addition, the experiment results reveal that 3-Grams is more accurate than 2-Grams and 4-Grams for feature extraction. Also, combination of attributes tend to result higher accuracy.

Keywords: Keystroke Authentication, Pattern recognition, MachineLearning, Instance-based Learning, Bayesian, Decision Tree.

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1638 Dextran/Poly(L-histidine) Graft Copolymer for pH-Responsive Drug Delivery

Authors: Dae Hwan Kang, Young-IL Jeong, Chung-Wook Chung

Abstract:

pH-sensitive drug targeting using nanoparticles for cancer chemotherapy have been spotlighted in recent decades. Graft copolymer composed of poly (L-histidine) (PHS) and dextran (DexPHS) was synthesized and pH-sensitive nanoparticles were fabricated for pH-responsive drug delivery of doxorubicin (DOX). Nanoparticles of DexPHS showed pH-sensitive changes in particle sizes and drug release behavior, i.e. particle sizes and drug release rate were increased at acidic pH, indicating that DexPHS nanoparticles have pH-sensitive drug delivery potentials. Antitumor activity of DOX-incorporated DexPHS nanoparticles were studied using CT26 colorectal carcinoma cells. Results indicated that fluorescence intensity was higher at acidic pH than basic pH. These results indicated that DexPHS nanoparticles have pH-responsive drug targeting.

Keywords: pH-sensitive polymer, nanoparticles, block copolymer, poly (L-histidine).

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1637 Towards Benchmarking English Residential Gas Consumption

Authors: J.Morris, D.Allinson, J.Harrison, K.J. Lomas

Abstract:

The UK Government has emphasized the role of Local Authorities as a key player in its flagship residential energy efficiency strategies, by identifying and targeting areas for energy efficiency improvements. Residential energy consumption in England is characterized by significant geographical variation in energy demand, which makes centralized targeting of areas for energy efficiency intervention difficult. This paper draws on research which aims to understand how demographic, social, economic, urban form and climatic factors influence the geographical variations in English residential gas consumption. The paper reports the findings of a multiple regression model that shows how 64% of the geographical variation in residential gas consumption is accounted for by variations in these factors. Results from this study, after further refinement and validation, can be used by Local Authorities to identify areas within their boundaries that have higher than expected gas consumption, these may be prime targets for energy efficiency initiatives.

Keywords: UK Housing, Heating Energy, Socio-Economics, Statistical Modelling

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1636 Dynamic Visualization on Student's Performance, Retention and Transfer of Procedural Learning

Authors: Fauzy M. Wan, Reem S.A. Baragash

Abstract:

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

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1635 Identification of LTI Autonomous All Pole System Using Eigenvector Algorithm

Authors: Sudipta Majumdar

Abstract:

This paper presents a method for identification of a linear time invariant (LTI) autonomous all pole system using singular value decomposition. The novelty of this paper is two fold: First, MUSIC algorithm for estimating complex frequencies from real measurements is proposed. Secondly, using the proposed algorithm, we can identify the coefficients of differential equation that determines the LTI system by switching off our input signal. For this purpose, we need only to switch off the input, apply our complex MUSIC algorithm and determine the coefficients as symmetric polynomials in the complex frequencies. This method can be applied to unstable system and has higher resolution as compared to time series solution when, noisy data are used. The classical performance bound, Cramer Rao bound (CRB), has been used as a basis for performance comparison of the proposed method for multiple poles estimation in noisy exponential signal.

Keywords: MUSIC algorithm, Cramer Rao bound, frequency estimation.

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1634 Relationship between Codependency, Perceived Social Support, and Depression in Mothers of Children with Intellectual Disability

Authors: Sajed Yaghoubnezhad, Mina Karimi, Seyede Marjan Modirkhazeni

Abstract:

The goal of this research was to study the relationship between codependency, perceived social support and depression in mothers of children with intellectual disability (ID). The correlational method was used in this study. The research population is comprised of mothers of educable children with ID in the age range of 25 to 61 years. From among this, a sample of 251 individuals, in the multistage cluster sampling method, was selected from educational districts in Tehran, who responded to the Spann-Fischer Codependency Scale (SFCDS), the Social Support Questionnaire and the Beck Depression Inventory (BDI). The findings of this study indicate that among mothers of children with ID depression has a positive and significant correlation with codependency (P<0.01, r=0.4) and a negative and significant correlation with the total score of social support (P<0.01, r=-0.34). Moreover, the results of stepwise multiple regression analysis showed that codependency is allocated a higher variance than social support in explaining depression (R2=0.023).

Keywords: Codependency, social support, depression, mothers of children with ID.

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1633 A Wind Farm Reduced Order Model Using Integral Manifold Theory

Authors: M. Sedighizadeh, A. Rezazadeh

Abstract:

Due to the increasing penetration of wind energy, it is necessary to possess design tools that are able to simulate the impact of these installations in utility grids. In order to provide a net contribution to this issue a detailed wind park model has been developed and is briefly presented. However, the computational costs associated with the performance of such a detailed model in describing the behavior of a wind park composed by a considerable number of units may render its practical application very difficult. To overcome this problem integral manifolds theory has been applied to reduce the order of the detailed wind park model, and therefore create the conditions for the development of a dynamic equivalent which is able to retain the relevant dynamics with respect to the existing a.c. system. In this paper integral manifold method has been introduced for order reduction. Simulation results of the proposed method represents that integral manifold method results fit the detailed model results with a higher precision than singular perturbation method.

Keywords: Wind, Reduced Order, Integral Manifold.

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1632 Developing Creative and Critically Reflective Digital Learning Communities

Authors: W. S. Barber, S. L. King

Abstract:

This paper is a qualitative case study analysis of the development of a fully online learning community of graduate students through arts-based community building activities. With increasing numbers and types of online learning spaces, it is incumbent upon educators to continue to push the edge of what best practices look like in digital learning environments. In digital learning spaces, instructors can no longer be seen as purveyors of content knowledge to be examined at the end of a set course by a final test or exam. The rapid and fluid dissemination of information via Web 3.0 demands that we reshape our approach to teaching and learning, from one that is content-focused to one that is process-driven. Rather than having instructors as formal leaders, today’s digital learning environments require us to share expertise, as it is the collective experiences and knowledge of all students together with the instructors that help to create a very different kind of learning community. This paper focuses on innovations pursued in a 36 hour 12 week graduate course in higher education entitled “Critical and Reflective Practice”. The authors chronicle their journey to developing a fully online learning community (FOLC) by emphasizing the elements of social, cognitive, emotional and digital spaces that form a moving interplay through the community. In this way, students embrace anywhere anytime learning and often take the learning, as well as the relationships they build and skills they acquire, beyond the digital class into real world situations. We argue that in order to increase student online engagement, pedagogical approaches need to stem from two primary elements, both creativity and critical reflection, that are essential pillars upon which instructors can co-design learning environments with students. The theoretical framework for the paper is based on the interaction and interdependence of Creativity, Intuition, Critical Reflection, Social Constructivism and FOLCs. By leveraging students’ embedded familiarity with a wide variety of technologies, this case study of a graduate level course on critical reflection in education, examines how relationships, quality of work produced, and student engagement can improve by using creative and imaginative pedagogical strategies. The authors examine their professional pedagogical strategies through the lens that the teacher acts as facilitator, guide and co-designer. In a world where students can easily search for and organize information as self-directed processes, creativity and connection can at times be lost in the digitized course environment. The paper concludes by posing further questions as to how institutions of higher education may be challenged to restructure their credit granting courses into more flexible modules, and how students need to be considered an important part of assessment and evaluation strategies. By introducing creativity and critical reflection as central features of the digital learning spaces, notions of best practices in digital teaching and learning emerge.

Keywords: Online, pedagogy, learning, communities.

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1631 Degradation Propensity of Welded Mild Steel in Coastal Soil of University of Lagos

Authors: S. O. Adeosun, O. S. Sanni

Abstract:

Study on corrosion propensity of welded mild steel- bar in soil media around the coastal area of University of Lagos has been carried out using gravimetric method. Six (6) samples each for welded and unwelded mild steels were cut, their initial weights were recorded and buried in two selected soil. The weight losses of these coupons were measured at regular intervals for a period of six months (180 days).

The corrosiveness of the soil media varied widely depending on the potency level of its constituents. The results revealed that soil in the studied area have marked variations in composition and contents. Soil medium with a lower pH and higher chloride ion concentration aggressively attacked the coupons with the welded steel coupon corroding faster than unwelded one. The medium resistivity to the flow of current is another strong factor affecting corrosion rate.

Keywords: Coastal area, corrosion rate, mild steel, soil media, welds.

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1630 Impact of Height of Silicon Pillar on Vertical DG-MOSFET Device

Authors: K. E. Kaharudin, A. H. Hamidon, F. Salehuddin

Abstract:

Vertical Double Gate (DG) Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is believed to suppress various short channel effect problems. The gate to channel coupling in vertical DG-MOSFET are doubled, thus resulting in higher current density. By having two gates, both gates are able to control the channel from both sides and possess better electrostatic control over the channel. In order to ensure that the transistor possess a superb turn-off characteristic, the subs-threshold swing (SS) must be kept at minimum value (60-90mV/dec). By utilizing SILVACO TCAD software, an n-channel vertical DG-MOSFET was successfully designed while keeping the sub-threshold swing (SS) value as minimum as possible. From the observation made, the value of sub-threshold swing (SS) was able to be varied by adjusting the height of the silicon pillar. The minimum value of sub-threshold swing (SS) was found to be 64.7mV/dec with threshold voltage (VTH) of 0.895V. The ideal height of the vertical DG-MOSFET pillar was found to be at 0.265 µm.

Keywords: DG-MOSFET, pillar, SCE, vertical

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1629 Incineration of Sludge in a Fluidized-Bed Combustor

Authors: Chien-Song Chyang, Yu-Chi Wang

Abstract:

For sludge disposal, incineration is considered to be better than direct burial because of regulations and space limitations in Taiwan. Additionally, burial after incineration can effectively prolong the lifespan of a landfill. Therefore, it is the most satisfactory method for treating sludge at present. Of the various incineration technologies, the fluidized bed incinerator is a suitable choice due to its fuel flexibility. In this work, sludge generated from industrial plants was treated in a pilot-scale vortexing fluidized bed. The moisture content of the sludge was 48.53%, and its LHV was 454.6 kcal/kg. Primary gas and secondary gas were fixed at 3 Nm3/min and 1 Nm3/min, respectively. Diesel burners with on-off controllers were used to control the temperature; the bed temperature was set to 750±20 °C, and the freeboard temperature was 850±20 °C. The experimental data show that the NO emission increased with bed temperature. The maximum NO emission is 139 ppm, which is in agreement with the regulation. The CO emission is low than 100 ppm through the operation period. The mean particle size of fly ash collected from baghouse decreased with operating time. The ration of bottom ash to fly ash is about 3. Compared with bottom ash, the potassium in the fly ash is much higher. It implied that the potassium content is not the key factor for aggregation of bottom ash.

Keywords: Sludge incineration, fluidized bed combustion, fly ash, bottom ash.

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1628 Revisiting the Concept of Risk Analysis within the Context of Geospatial Database Design: A Collaborative Framework

Authors: J. Grira, Y. Bédard, S. Roche

Abstract:

The aim of this research is to design a collaborative framework that integrates risk analysis activities into the geospatial database design (GDD) process. Risk analysis is rarely undertaken iteratively as part of the present GDD methods in conformance to requirement engineering (RE) guidelines and risk standards. Accordingly, when risk analysis is performed during the GDD, some foreseeable risks may be overlooked and not reach the output specifications especially when user intentions are not systematically collected. This may lead to ill-defined requirements and ultimately in higher risks of geospatial data misuse. The adopted approach consists of 1) reviewing risk analysis process within the scope of RE and GDD, 2) analyzing the challenges of risk analysis within the context of GDD, and 3) presenting the components of a risk-based collaborative framework that improves the collection of the intended/forbidden usages of the data and helps geo-IT experts to discover implicit requirements and risks.

Keywords: Collaborative risk analysis, intention of use, Geospatial database design, Geospatial data misuse.

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1627 Instructional Design Practitioners in Malaysia: Skills and Issues

Authors: Irfan N. Umar, Yong Su-Lyn

Abstract:

The purpose of this research is to determine the knowledge and skills possessed by instructional design (ID) practitioners in Malaysia. As ID is a relatively new field in the country and there seems to be an absence of any studies on its community of practice, the main objective of this research is to discover the tasks and activities performed by ID practitioners in educational and corporate organizations as suggested by the International Board of Standards for Training, Performance and Instruction. This includes finding out the ID models applied in the course of their work. This research also attempts to identify the barriers and issues as to why some ID tasks and activities are rarely or never conducted. The methodology employed in this descriptive study was a survey questionnaire sent to 30 instructional designers nationwide. The results showed that majority of the tasks and activities are carried out frequently enough but omissions do occur due to reasons such as it being out of job scope, the decision was already made at a higher level, and the lack of knowledge and skills. Further investigations of a qualitative manner should be conducted to achieve a more in-depth understanding of ID practices in Malaysia

Keywords: instructional design, ID competencies, ID models, IBSTPI

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1626 Creative Thinking Skill Approach Through Problem-Based Learning: Pedagogy and Practice in the Engineering Classroom

Authors: Halizah Awang, Ishak Ramly

Abstract:

Problem-based learning (PBL) is one of the student centered approaches and has been considered by a number of higher educational institutions in many parts of the world as a method of delivery. This paper presents a creative thinking approach for implementing Problem-based Learning in Mechanics of Structure within a Malaysian Polytechnics environment. In the learning process, students learn how to analyze the problem given among the students and sharing classroom knowledge into practice. Further, through this course-s emphasis on problem-based learning, students acquire creative thinking skills and professional skills as they tackle complex, interdisciplinary and real-situation problems. Once the creative ideas are generated, there are useful additional techniques for tender ideas that will grow into a productive concept or solution. The combination of creative skills and technical abilities will enable the students to be ready to “hit-the-ground-running" and produce in industry when they graduate.

Keywords: Creative Thinking Skills, Problem-based Learning, Problem Solving.

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1625 Accelerated Microwave Extraction of Natural Product using the Cryogrinding

Authors: F. Benkaci-Ali, R. Mekaoui, G. Eppe, E. De Pau, J. F. Faucont

Abstract:

Team distillation assisted by microwave extraction (SDAM) considered as accelerated technique extraction is a combination of microwave heating and steam distillation, performed at atmospheric pressure. SDAM has been compared with the same technique coupled with the cryogrinding of seeds (SDAM -CG). Isolation and concentration of volatile compounds are performed by a single stage for the extraction of essential oil from Cuminum cyminum seeds. The essential oils extracted by these two methods for 5 min were quantitatively (yield) and qualitatively (aromatic profile) no similar. These methods yield an essential oil with higher amounts of more valuable oxygenated compounds, and allow substantial savings of costs, in terms of time, energy and plant material. SDAM and SDAM-CG is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.

Keywords: Steam distillation, microwave extraction, Cuminum cyminum, chromatography, mass spectrometry

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1624 Evolving Digital Circuits for Early Stage Breast Cancer Detection Using Cartesian Genetic Programming

Authors: Zahra Khalid, Gul Muhammad Khan, Arbab Masood Ahmad

Abstract:

Cartesian Genetic Programming (CGP) is explored to design an optimal circuit capable of early stage breast cancer detection. CGP is used to evolve simple multiplexer circuits for detection of malignancy in the Fine Needle Aspiration (FNA) samples of breast. The data set used is extracted from Wisconsins Breast Cancer Database (WBCD). A range of experiments were performed, each with different set of network parameters. The best evolved network detected malignancy with an accuracy of 99.14%, which is higher than that produced with most of the contemporary non-linear techniques that are computational expensive than the proposed system. The evolved network comprises of simple multiplexers and can be implemented easily in hardware without any further complications or inaccuracy, being the digital circuit.

Keywords: Breast cancer detection, cartesian genetic programming, evolvable hardware, fine needle aspiration (FNA).

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1623 Voice Features as the Diagnostic Marker of Autism

Authors: Elena Lyakso, Olga Frolova, Yuri Matveev

Abstract:

The aim of the study is to determine the acoustic features of voice and speech of children with autism spectrum disorders (ASD) as a possible additional diagnostic criterion. The participants in the study were 95 children with ASD aged 5-16 years, 150 typically development (TD) children, and 103 adults – listening to children’s speech samples. Three types of experimental methods for speech analysis were performed: spectrographic, perceptual by listeners, and automatic recognition. In the speech of children with ASD, the pitch values, pitch range, values of frequency and intensity of the third formant (emotional) leading to the “atypical” spectrogram of vowels are higher than corresponding parameters in the speech of TD children. High values of vowel articulation index (VAI) are specific for ASD children’s speech signals. These acoustic features can be considered as diagnostic marker of autism. The ability of humans and automatic recognition of the psychoneurological state of children via their speech is determined.

Keywords: Autism spectrum disorders, biomarker of autism, child speech, voice features.

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1622 An Efficient VLSI Design Approach to Reduce Static Power using Variable Body Biasing

Authors: Md. Asif Jahangir Chowdhury, Md. Shahriar Rizwan, M. S. Islam

Abstract:

In CMOS integrated circuit design there is a trade-off between static power consumption and technology scaling. Recently, the power density has increased due to combination of higher clock speeds, greater functional integration, and smaller process geometries. As a result static power consumption is becoming more dominant. This is a challenge for the circuit designers. However, the designers do have a few methods which they can use to reduce this static power consumption. But all of these methods have some drawbacks. In order to achieve lower static power consumption, one has to sacrifice design area and circuit performance. In this paper, we propose a new method to reduce static power in the CMOS VLSI circuit using Variable Body Biasing technique without being penalized in area requirement and circuit performance.

Keywords: variable body biasing, state saving technique, stack effect, dual V-th, static power reduction.

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1621 Phenolic Compounds in Red Fruits Produced in Organic Farming at Maturation Stage

Authors: Susana M. A. Soutinho, Raquel P. F. Guiné, António M. Jordão, Fernando J. Gonçalves

Abstract:

The agricultural organic farming is different from conventional farming in a way that is aimed at providing a balanced and constructive action in agricultural systems. With the increase in intensive agriculture, undesirable changes were being observed in ecosystems with irreparable damage being caused to the natural equilibrium. This is the reason for the increasing interest in organic farming as an environment friendly agricultural production method. In the present work three red fruits produced in organic farming were analyzed, namely raspberry, gooseberry and blueberry. The samples were harvested in a local farm when at plain maturation. The results obtained allowed to conclude that the blueberry contained higher amounts of phenolic compounds, total tannins and total anthocyanins than raspberry and gooseberry. Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied.

Keywords: Blackberry, gooseberry, organic farming, phenolic compounds, raspberry.

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1620 Carotenoid Potential to Protect Cow-s Milk Fat Against Oxidative Deterioration

Authors: U. Antone, V. Sterna, J. Zagorska

Abstract:

Milk from differently fed cows (supplemented with carotenoids from carrots or palm oil product Carotino CAF 100) was obtained in a conventional dairy farm to assess the carotenoid potential to protect milk fat against oxidation. The extracted anhydrous milk fat (AMF) was tested by peroxide value, and Rancimat tests. Temperature, and light stimulation for reaction acceleration was used. The oxidative stability enhancement by carotenoids was detected in peroxide value test – the strongest effect was observed in palm oil, following by carrot supplemented group, compared to control group, whose feed was unchanged. Rancimat accelerated oxidation test results did not show any superiority of the oxidative stability of the AMF samples from milk of the carotenoidsupplemented cow groups. The average oxidation stability of AMF dark-stored samples was 12.59 ± 0.294 h, and it was significantly (p < 0.05) higher than that of AMF light-affected samples, i.e. 2.60 ± 0.191 h.

Keywords: antioxidants, dairy products, forages, lipid aging, peroxide

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1619 Methods of Forming Informational Culture Students

Authors: Altynbek Moshkalov

Abstract:

Along with the basic features of students\' culture information, with its widely usage oriented on implementation of the new information technologies in educational process that determines the search for ways of pointing to the similarity of interdisciplinary connections content, aims and objectives of the study. In this regard, the article questions about students\' information culture, and also presented information about the aims and objectives of the information culture process among students. In the formation of a professional interest in relevant information, which is an opportunity to assist in informing the professional activities of the essence of effective use of interactive methods and innovative technologies in the learning process. The result of the experiment proves the effectiveness of the information culture process of students in training the system of higher education based on the credit technology. The main purpose of this paper is a comprehensive review of students\' information culture.

Keywords: Information culture, methods of information culture of students, educational system of the credit technology, distance learning, information of interest, information and communication technologies and tools.

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1618 A Parametric Study on the Backwater Level Due to a Bridge Constriction

Authors: S. Atabay, T. A. Ali, Md. M. Mortula

Abstract:

This paper presents the results and findings from a parametric study on the water surface elevation at upstream of bridge constriction for subcritical flow. In this study, the influence of Manning's Roughness Coefficient of main channel (nmc) and floodplain (nfp), and bridge opening (b) flow rate (Q), contraction (kcon) and expansion coefficients (kexp) were investigated on backwater level. The DECK bridge models with different span widths and without any pier were investigated within the two stage channel having various roughness conditions. One of the most commonly used commercial one-dimensional HEC-RAS model was used in this parametric study. This study showed that the effects of main channel roughness (nmc) and flow rate (Q) on the backwater level are much higher than those of the floodplain roughness (nfp). Bridge opening (b) with contraction (kcon) and expansion coefficients (kexp) have very little effect on the backwater level within this range of parameters.

Keywords: Bridge backwater, parametric study and waterways.

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1617 Students´ Knowledge, or Random Choice in ESP?

Authors: Ivana Šimonová

Abstract:

As widely accepted, didactic multiple-choice tests are referred as a tool providing feedback easily and quickly. Despite the final test scores are corrected by a special formula and number of high plausibility distractors is taken into consideration, the results may be influenced by the random choice. The survey was held in three academic years at the Faculty of Informatics and Management, University of Hradec Kralove, Czech Republic, where the multiple-choice test scores were compared to the open-answer ones. The research sample included 567 respondents. The collected data were processed by the NCSS2007 statistic software by the method of frequency and multiple regression analysis and presented in the form of figures and tables. The results proved statistically significant differences in test scores in academic years 2 and 3, and were discussed from the point of the credit system and conditions for teaching/learning English in the Czech education system.

Keywords: ESP, higher education, multiple-choice test, open-answer test.

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1616 A Pre-Assessment Questionnaire to Identify Healthcare Professionals’ Perception on Information Technology Implementation

Authors: Y. Atilgan Şengül

Abstract:

Health information technologies promise higher quality, safer care and much more for both patients and professionals. Despite their promise, they are costly to develop and difficult to implement. On the other hand, user acceptance and usage determine the success of implemented information technology in healthcare. This study provides a model to understand health professionals’ perception and expectation of health information technology. Extensive literature review has been conducted to determine the main factors to be measured. A questionnaire has been designed as a measurement model and submitted to the personnel of an in vitro fertilization clinic. The respondents’ degree of agreement according to five-point Likert scale was 72% for convenient access to data and 69.4% for the importance of data security. There was a significant difference in acceptance of electronic data storage for female respondents. Also, other significant differences between professions were obtained.

Keywords: Healthcare, health informatics, medical record system, questionnaire.

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1615 Determination of Severe Loading Condition at Critical System Cascading Collapse Considering the Effect of Protection System Hidden Failure

Authors: N. A. Salim, M. M. Othman, I. Musirin, M. S. Serwan

Abstract:

Hidden failure in a protection system has been recognized as one of the main reasons which may cause to a power system instability leading to a system cascading collapse. This paper presents a computationally systematic approach used to obtain the estimated average probability of a system cascading collapse by considering the effect of probability hidden failure in a protection system. The estimated average probability of a system cascading collapse is then used to determine the severe loading condition contributing to the higher risk of critical system cascading collapse. This information is essential to the system utility since it will assist the operator to determine the highest point of increased system loading condition prior to the event of critical system cascading collapse.

Keywords: Critical system cascading collapse, protection system hidden failure, severe loading condition.

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1614 Design of Nonlinear Observer by Using Augmented Linear System based on Formal Linearization of Polynomial Type

Authors: Kazuo Komatsu, Hitoshi Takata

Abstract:

The objective of this study is to propose an observer design for nonlinear systems by using an augmented linear system derived by application of a formal linearization method. A given nonlinear differential equation is linearized by the formal linearization method which is based on Taylor expansion considering up to the higher order terms, and a measurement equation is transformed into an augmented linear one. To this augmented dimensional linear system, a linear estimation theory is applied and a nonlinear observer is derived. As an application of this method, an estimation problem of transient state of electric power systems is studied, and its numerical experiments indicate that this observer design shows remarkable performances for nonlinear systems.

Keywords: nonlinear system, augmented linear system, nonlinear observer, formal linearization, electric power system.

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1613 Effects of Sodium Bicarbonate Content and Vulcanization Method on Properties of NBR/PVC Thermal Insulator Foam

Authors: P. Suriyachai, N. Thavarungkul, P. Sae-oui

Abstract:

In this research sodium bicarbonate (NaHCO3) was introduced to generate carbon dioxide gas (CO2) to the existing nitrogen gas (N2) of elastomeric foam, to lower thermal conductivity (K). Various loadings of NaHCO3 (0 to 60 phr) were added into the azodicarbonamide (AZC)-containing compound and its properties were then determined. Two vulcanization methods, i.e., hot air and infrared (IR), were employed and compared in this study. Results revealed that compound viscosity tended to increase slightly with increasing NaHCO3 content but cure time was delayed. The effect of NaHCO3 content on thermal conductivity depended on the vulcanization method. For hot air method, the thermal conductivity was insignificantly changed with increasing NaHCO3 up to 40 phr whereas it tended to decrease gradually for IR method. At higher NaHCO3 content (60 phr), unexpected increase of thermal conductivity was observed. The water absorption was also determined and foam structures were then used to explain the results.

Keywords: sodium bicarbonate, thermal conductivity, hot airmethod, infrared method

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1612 Evaluation of Internet Anxiety in SRBIAU Higher Education Students in Research Process

Authors: Nima Babazadeh Gashti, Nazanin Pilevari

Abstract:

Increase in using internet makes some problems that one of them is "internet anxiety". Internet anxiety is a type of anxious that people may feel during surfing internet or using internet for their educational purpose, blogging or streaming to digital libraries. The goal of this study is evaluating of internet anxiety among the management students. In this research Ealy's internet anxiety questionnaire, consists of positive and negative items, is completed by 310 participants. According to the findings, about 64.7% of them were equal or below to mean anxiety score (50). The distribution of internet anxiety scores was normal and there was no meaningful difference between men-s and women's anxiety level in this sample. Results also showed that there is no meaningful difference of internet anxiety level between different fields of study in Management. This evaluation will help managers to perform gap analysis between the existent level and the desired one. Future work would be providing techniques for abating human anxiety while using internet via human computer interaction techniques.

Keywords: Internet, anxiety, research process, internet identification, human computer interaction.

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1611 Subcritical Water Extraction of Mannitol from Olive Leaves

Authors: S. M. Ghoreishi, R. Gholami Shahrestani, S. H. Ghaziaskar

Abstract:

Subcritical water extraction was investigated as a novel and alternative technology in the food and pharmaceutical industry for the separation of Mannitol from olive leaves and its results was compared with those of Soxhlet extraction. The effects of temperature, pressure, and flow rate of water and also momentum and mass transfer dimensionless variables such as Reynolds and Peclet Numbers on extraction yield and equilibrium partition coefficient were investigated. The 30-110 bars, 60-150°C, and flow rates of 0.2-2 mL/min were the water operating conditions. The results revealed that the highest Mannitol yield was obtained at 100°C and 50 bars. However, extraction of Mannitol was not influenced by the variations of flow rate. The mathematical modeling of experimental measurements was also investigated and the model is capable of predicting the experimental measurements very well. In addition, the results indicated higher extraction yield for the subcritical water extraction in contrast to Soxhlet method.

Keywords: Extraction, Mannitol, Modeling, Olive leaves, Soxhlet extraction, Subcritical water.

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1610 Enhancing Power Conversion Efficiency of P3HT/PCBM Polymer Solar Cells

Authors: Nidal H. Abu-Zahra, Mahmoud Algazzar

Abstract:

In this research, n-dodecylthiol was added to P3HT/ PC70BM polymer solar cells to improve the crystallinity of P3HT and enhance the phase separation of P3HT/PC70BM. The improved crystallinity of P3HT:PC70BM doped with 0-5% by volume of n-dodecylthiol resulted in improving the power conversion efficiency of polymer solar cells by 33%. In addition, thermal annealing of the P3HT/PC70MB/n-dodecylthiolcompound showed further improvement in crystallinity with n-dodecylthiol concentration up to 2%. The highest power conversion efficiency of 3.21% was achieved with polymer crystallites size L of 11.2nm, after annealing at 150°C for 30 minutes under a vacuum atmosphere. The smaller crystallite size suggests a shorter path of the charge carriers between P3HT backbones, which could be beneficial to getting a higher short circuit current in the devices made with the additive. 

Keywords: n-dodecylthiol, Congugated PSC, P3HT/PCBM, Polymer Solar Cells.

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