Search results for: sound transmission class
4854 Systems Approach on Thermal Analysis of an Automatic Transmission
Authors: Sinsze Koo, Benjin Luo, Matthew Henry
Abstract:
In order to increase the performance of an automatic transmission, the automatic transmission fluid is required to be warm up to an optimal operating temperature. In a conventional vehicle, cold starts result in friction loss occurring in the gear box and engine. The stop and go nature of city driving dramatically affect the warm-up of engine oil and automatic transmission fluid and delay the time frame needed to reach an optimal operating temperature. This temperature phenomenon impacts both engine and transmission performance but also increases fuel consumption and CO2 emission. The aim of this study is to develop know-how of the thermal behavior in order to identify thermal impacts and functional principles in automatic transmissions. Thermal behavior was studied using models and simulations, developed using GT-Suit, on a one-dimensional thermal and flow transport. A power train of a conventional vehicle was modeled in order to emphasis the thermal phenomena occurring in the various components and how they impact the automatic transmission performance. The simulation demonstrates the thermal model of a transmission fluid cooling system and its component parts in warm-up after a cold start. The result of these analyses will support the future designs of transmission systems and components in an attempt to obtain better fuel efficiency and transmission performance. Therefore, these thermal analyses could possibly identify ways that improve existing thermal management techniques with prioritization on fuel efficiency.Keywords: thermal management, automatic transmission, hybrid, and systematic approach
Procedia PDF Downloads 3774853 Available Transmission Transfer Efficiency (ATTE) as an Index Measurement for Power Transmission Grid Performance
Authors: Ahmad Abubakar Sadiq, Nwohu Ndubuka Mark, Jacob Tsado, Ahmad Adam Asharaf, Agbachi E. Okenna, Enesi E. Yahaya, Ambafi James Garba
Abstract:
Transmission system performance analysis is vital to proper planning and operations of power systems in the presence of deregulation. Key performance indicators (KPIs) are often used as measure of degree of performance. This paper gives a novel method to determine the transmission efficiency by evaluating the ratio of real power losses incurred from a specified transfer direction. Available Transmission Transfer Efficiency (ATTE) expresses the percentage of real power received resulting from inter-area available power transfer. The Tie line (Rated system path) performance is seen to differ from system wide (Network response) performance and ATTE values obtained are transfer direction specific. The required sending end quantities with specified receiving end ATC and the receiving end power circle diagram are obtained for the tie line analysis. The amount of real power loss load relative to the available transfer capability gives a measure of the transmission grid efficiency.Keywords: performance, transmission system, real power efficiency, available transfer capability
Procedia PDF Downloads 6494852 The Construction of Research-Oriented/Practice-Oriented Engineering Testing and Measurement Technology Course under the Condition of New Technology
Authors: He Lingsong, Wang Junfeng, Tan Qiong, Xu Jiang
Abstract:
The paper describes efforts on reconstruction methods of engineering testing and measurement technology course by applying new techniques and applications. Firstly, flipped classroom was introduced. In-class time was used for in-depth discussions and interactions while theory concept teaching was done by self-study course outside of class. Secondly, two hands-on practices of technique applications, including the program design of MATLAB Signal Analysis and the measurement application of Arduino sensor, have been covered in class. Class was transformed from an instructor-centered teaching process into an active student-centered learning process, consisting of the pre-class massive open online course (MOOC), in-class discussion and after-class practice. The third is to change sole written homework to the research-oriented application practice assignments, so as to enhance the breadth and depth of the course.Keywords: testing and measurement, flipped classroom, MOOC, research-oriented learning, practice-oriented learning
Procedia PDF Downloads 1474851 Numerical Analyze of Corona Discharge on HVDC Transmission Lines
Authors: H. Nouri, A. Tabbel, N. Douib, H. Aitsaid, Y. Zebboudj
Abstract:
This study and the field test comparisons were carried out on the Algerian Derguna-Setif transmission systems. The transmission line of normal voltage 225 kV is 65 km long, transported and uses twin bundle conductors protected with two shield wires of transposed galvanized steel. An iterative finite-element method is used to solve Poisons equation. Two algorithms are proposed for satisfying the current continuity condition and updating the space-charge density. A new approach to the problem of corona discharge in transmission system has been described in this paper. The effect of varying the configurations and wires number is also investigated. The analysis of this steady is important in the design of HVDC transmission lines. The potential and electric field have been calculating in locations singular points of the system.Keywords: corona discharge, finite element method, electric field, HVDC
Procedia PDF Downloads 4144850 Localized Dynamic Lensing with Extended Depth of Field via Enhanced Light Sound Interaction
Authors: Hamid R. Chabok, Demetrios N. Christodoulides, Mercedeh Khajavikhan
Abstract:
In recent years, acousto-optic (AO) lenses with tunable foci have emerged as a powerful tool for optical beam shaping, imaging, and particle manipulation. In most current AO lenses, the incident light that propagates orthogonally to a standing ultrasonic wave converts to a Bessel-like beam pattern due to the Raman-Nath effect, thus forming annular fringes that result in compromised focus response. Here, we report a new class of AO dynamic lensing based on generating a 3D-variable refractive index profile via a z-axis-scan ultrasound transducer. By utilizing the co- /counter propagation of light and acoustic waves that interact over a longer distance, the laser beam can be strongly focused in a fully controllable manner. Using this approach, we demonstrate AO lenses with instantaneous extended depth of field (DoF) and laterally localized dynamic focusing. This new light-sound interaction scheme may pave the way towards applications that require remote focusing, 3D micromanipulation, and deep tissue therapy/imaging.Keywords: acousto-optic, optical beam shaping, dynamic lensing, ultrasound
Procedia PDF Downloads 1014849 The Relation Between Social Class, Race Homophily and Mental Health Outcomes of Black College Students
Authors: Omari W. Keeles
Abstract:
Attention to social class and race processes could illuminate within- group differences in Black students' experiences that help explain variation in adjustment. Of interest is how social class relates to development of intragroup connections with other Black students on campus in ways that promote or inhibit well-being. The present study’s findings suggest that students from lower class backgrounds may be more restrictive or limited in opportunities around their intragroup friendship networks than more affluent students. Furthermore, Black social relationship networks were related to positive mental health adjustment important to healthy psychological functioning and development.Keywords: black students, social class, homophily, psychological adjustment
Procedia PDF Downloads 4504848 Acoustic Behavior of Polymer Foam Composite of Shorea leprosula after UV-Irradiation Exposure
Authors: Anika Zafiah M. Rus, S. Shafizah
Abstract:
This study was developed to compare the behavior and the ability of polymer foam composites towards sound absorption test of Shorea leprosula wood (SL) of acid hydrolysis treatment with particle size < 355µm. Three different weight ratio of polyol to wood particle has been selected which are 10wt%, 15wt%, and 20wt%. The acid hydrolysis treatment is to optimize the surface interaction of a wood particle with polymer foam matrix. In addition, the acoustic characteristic of sound absorption coefficient (Į) was determined. Further treatment is to expose the polymer composite in UV irradiation by using UV-Weatherometer. Polymer foam composite of untreated shorea leprosula particle (SL-B) with respective percentage loading shows uniform pore structure as compared with treated wood particle (SL-A). As the filler percentage loading in polymer foam increases, the Į value approaching 1 for both samples. Furthermore, SL-A shows better Į value at 3500-4500 frequency absorption level(Hz), meanwhile Į value for SL-B is maximum at 4000-5000 Hz. The frequencies absorption level for both SL-B and SL-A after UV exposure was increased with the increasing of exposure time from 0-1000 hours. It is, therefore, concluded that the Į for each sound absorbing material, with or without acid hydrolysis treatment of wood particles and it’s percentages loading in polymer matrix effect the sound absorption behavior.Keywords: polymer foam composite, sound absorption coefficient, UV-irradiation, wood
Procedia PDF Downloads 4654847 A Marxist Analysis of Toni Morrison's Novel, The Bluest Eye
Authors: Irfan Mehmood
Abstract:
The goal of this study is to examine The Bluest Eye (1979) by Toni Morrison from a Marxist perspective, a literary theory developed by Louis Althusser, which emphasizes capitalism and class conflict in the modern world. Marxist literary philosophy holds that the absence of opportunities for lower-class people to own and earn properties and resources of production is the main cause of their repression. In The Communist Manifesto (1848), Karl Marx divided society into two main classes, the proletariat (the lowest class) and the bourgeois (the ruling class). Marx contends that the proletarian class has been brutally exploited by the bourgeois class in all facets of existence. The exploitation of the lower class by means of hegemony and capitalism is covered by Toni Morrison in her first novel, The Bluest Eye (1979). The goal of this study is to determine how Morrison's chosen work highlights the struggle of oppressed African Americans against entrenched systems of hegemony, interpellation, and state apparatuses. This study will look more closely at the claim that all of the miseries experienced by Afro-Americans are mostly the result of the capitalist class structure and that they can also enjoy the blessings of life through unity, hard work, and economic stability.Keywords: class conflict; African American culture; hegemony; interpellation; state apparatuses
Procedia PDF Downloads 774846 Research on ARQ Transmission Technique in Mars Detection Telecommunications System
Authors: Zhongfei Cai, Hui He, Changsheng Li
Abstract:
This paper studied in the automatic repeat request (ARQ) transmission technique in Mars detection telecommunications system. An ARQ method applied to proximity-1 space link protocol was proposed by this paper. In order to ensure the efficiency of data reliable transmission, this ARQ method combined these different ARQ maneuvers characteristics. Considering the Mars detection communication environments, this paper analyzed the characteristics of the saturation throughput rate, packet dropping probability, average delay and energy efficiency with different ARQ algorithms. Combined thus results with the theories of ARQ transmission technique, an ARQ transmission project in Mars detection telecommunications system was established. The simulation results showed that this algorithm had excellent saturation throughput rate and energy efficiency with low complexity.Keywords: ARQ, mars, CCSDS, proximity-1, deepspace
Procedia PDF Downloads 3404845 Linking Pre-Class Engagement with Academic Achievement: The Role of Quests in a Flipped Chemistry Course
Authors: Anthony J. Rojas
Abstract:
In flipped classroom environments, students are tasked with engaging in pre-class learning to maximize the effectiveness of in-class time. This study investigates the use of ‘Quests’, brief formative assessments administered at the start of class, to evaluate student understanding of assigned pre-class materials in an undergraduate chemistry course. Students completed Quests via Microsoft Forms, based on content from instructional videos and worksheets, and these assessments were mandatory, with no opportunity for make-up. This paper examines the correlation between Quest performance and overall course success, finding that students who performed well on the Quests consistently achieved higher final grades in the course. The findings suggest that Quests are effective in both reinforcing student engagement with pre-class content and predicting their broader academic performance. The implications of these results for flipped classroom strategies and student learning outcomes will be discussed.Keywords: chemistry, flipped classroom, attendance, assessments
Procedia PDF Downloads 224844 Feeling, Thinking, Acting: The Role of Subjective Social Class and Social Class Identity on Emotions, Attitudes and Prosocial Behavior Towards Muslim Immigrants in Belgium
Authors: Theresa Zagers, Rita Guerra
Abstract:
Most research investigating how receiving communities perceive, and experience migration has overlooked the potential role of subjective social class and social class identity in positive intergroup relations and social cohesion of migrants and host societies. The present study aimed to provide insights to understand this relationship and focused on three important features: prosocial behaviour, attitudes and emotions towards Muslim immigrants in Flanders, Belgium. Building on relative deprivation-gratification theory we examined the indirect relationships of subjective social class on prosocial behaviour/intentions, attitudes and emotions via relative deprivation (RD), as well as the moderator role of the importance of social class identity. 431 Belgian participants participated in an online survey study. Overall, our results supported the predicted indirect effect of subjective social class: the lower the subjective social class, the higher the perceptions of relative deprivation, which in turn is related to less prosocial behaviour intentions, and more negative attitudes and emotions towards immigrants. This indirect effect was, however, not moderated by the importance of social class identity. Interestingly, the direct effects of subjective social class showed a different pattern: when bypassing deprivation our results showed higher subjective social class was detrimental for intergroup relations (more negative attitudes and emotions), and that lower subjective social class was positively related to prosocial intentions for those identifying highly with their class identity. Overall, we gained valuable insights in the relationship of subjective social class and the three features of intergroup relations.Keywords: social class, relative deprivation-gratification, prosocial behavior, attitudes, emotions, Muslim immigrants
Procedia PDF Downloads 594843 PV Module as a Design Element of Barriers for Protection against Noise
Authors: Budimir S. Sudimac, Andjela N. Dubljevic
Abstract:
The aim of thisresearch paper is to consider possibilities for improving the street lighting on the E75 highway, which passes through Serbia, using renewable sources of energy. In this paper, we analyzed the possibilities for installing sound barriers along the highway and integrating photovoltaic (PV) modules, which would generate electrical energy to power the lighting on the section of the highway running through Belgrade. The main aim of this paper is to analyze, show and promote innovative, hybrid, multi-functional solar technology using PV modules as an element of sound barriers in urban areas. The paper seeks to show the hybridity of using sustainable technologies in solving environmental issues. This structure solves the problem of noise in populated areas and provides the electricity from renewable source.Keywords: noise, PV modules, solar energy, sound barriers
Procedia PDF Downloads 4714842 Crude Oil and Stocks Markets: Prices and Uncertainty Transmission Analysis
Authors: Kamel Malik Bensafta, Gervasio Semedo
Abstract:
The purpose of this paper is to investigate the relationship between oil prices and socks markets. The empirical analysis in this paper is conducted within the context of Multivariate GARCH models, using a transform version of the so-called BEKK parameterization. We show that mean and uncertainty of US market are transmitted to oil market and European market. We also identify an important transmission from WTI prices to Brent Prices.Keywords: oil volatility, stock markets, MGARCH, transmission, structural break
Procedia PDF Downloads 5224841 Study of Ground Level Electric Field under 800 kV HVDC Unipolar Laboratory level Transmission line
Authors: K. Urukundu, K. A. Aravind, Pradeep M. Nirgude, K. Sandhya
Abstract:
Transmission of bulk power over a long distance through HVDC transmission lines is gaining importance. This is because the transfer of bulk power through HVDC, from generating stations to load centers over long distances is more economical. However, these HVDC transmission lines create environmental and interference effects under the right of way of the line due to the ionization of the surrounding atmosphere in the vicinity of HVDC lines. The measurement of ground-level electric field and ionic current density is essential for the evaluation of human effects due to electromagnetic interference of the HVDC transmission line. In this paper, experimental laboratory results of the ground-level electric field under the miniature model of 800 kV monopole HVDC line of length 8 meters are presented in lateral configuration with different heights of the conductor from the ground plane. The results are compared with the simulated test results obtained through Finite Element based software.Keywords: bundle, conductor, hexagonal, transmission line, ground-level electric field
Procedia PDF Downloads 2204840 Noise of Aircraft Flyovers Affects Reading Saccades
Authors: Svea Missfeldt, Rainer Höger
Abstract:
A number of studies show that aircraft noise around airports negatively affects the reading comprehension of children attending schools in the neighbourhood. Yet little is known about the underlying mechanisms. Explanatory approaches discuss the attention capturing effect of noise sources which occupy mental capacity. Research suggests that attentional capacities are especially demanded when different modalities are involved at the same time. To explore whether aircraft noise affects reading processes in specific manners, students read texts in variable sound conditions while their eye movements were recorded. Besides noise caused by aircraft flyovers, which represent moving sound sources, saccades were also recorded under the condition of white noise, a natural sound setting and silence for comparison. Data showed an increase in regressive saccades when the sound of moving sources was presented. Interestingly, this effect was significantly high when the aircrafts moved in the opposite of the reading direction. Especially the latter result is not compatible with the hypothesis of a general impairment of cognitive processes by noise where the direction of movement should not have an influence. Reading is assumed to be based on two different attentional mechanisms: overt and covert attention, where the latter supports control and pre-planning of eye movements during reading. We believe that covert attention is affected by moving sound sources, resulting in an enhanced number of backwardly directed saccades.Keywords: aircraft noise, attentional processes, cognition, eye movements, reading saccades
Procedia PDF Downloads 3284839 Certain Results of a New Class of Meromorphic Multivalent Functions Involving Ruscheweyh Derivative
Authors: Kassim A. Jassim
Abstract:
In the present paper, we introduce and discuss a new class Kp(λ,α) of meromorphic multivalent functions in the punctured unit disk U*={z∈¢:0<|z|<1} defined by Ruscheweyh derivative. We obtain some sufficient conditions for the functions belonging to the class Kp(λ,α).Keywords: meromorphic multivalent function, Ruscheweyh derivative, hadamard product
Procedia PDF Downloads 3364838 Data Rate Based Grouping Scheme for Cooperative Communications in Wireless LANs
Authors: Sunmyeng Kim
Abstract:
IEEE 802.11a/b/g standards provide multiple transmission rates, which can be changed dynamically according to the channel condition.Cooperative communications we reintroduced to improve the overallperformance of wireless LANs with the help of relay nodes with higher transmission rates. The cooperative communications are based on the fact that the transmission is much faster when sending data packets to a destination node through a relay node with higher transmission rate, rather than sending data directly to the destination node at low transmission rate. To apply the cooperative communications in wireless LAN, several MAC protocols have been proposed. Some of them can result in collisions among relay nodes in a dense network. In order to solve this problem, we propose a new protocol. Relay nodes are grouped based on their transmission rates. And then, relay nodes only in the highest group try to get channel access. Performance evaluation is conducted using simulation, and shows that the proposed protocol significantly outperforms the previous protocol in terms of throughput and collision probability.Keywords: cooperative communications, MAC protocol, relay node, WLAN
Procedia PDF Downloads 4664837 Surge Analysis of Water Transmission Mains in Una, Himachal Pradesh, India
Authors: Baldev Setia, Raj Rajeshwari, Maneesh Kumar
Abstract:
Present paper is an analysis of water transmission mains failed due to surge analysis by using basic software known as Surge Analysis Program (SAP). It is a real time failure case study of a pipe laid in Una, Himachal Pradesh. The transmission main is a 13 kilometer long pipe with 7.9 kilometers as pumping main and 5.1 kilometers as gravitational main. The analysis deals with mainly pumping mains. The results are available in two text files. Besides, several files are prepared with specific view to obtain results in a graphical form. These results help to observe the pressure difference and surge occurrence at different locations along the pipe profile, which help to redesign the transmission main with different but suitable safety measures against possible surge. A technically viable and economically feasible design has been provided as per the relevant manual and standard code of practice.Keywords: surge, water hammer, transmission mains, SAP 2000
Procedia PDF Downloads 3664836 Surge Analysis of Water Transmission Mains in Una, Himachal Pradesh (India)
Authors: Baldev Setia, Raj Rajeshwari, Maneesh Kumar
Abstract:
Present paper is an analysis of water transmission mains failed due to surge analysis by using basic software known as Surge Analysis Program (SAP). It is a real time failure case study of a pipe laid in Una, Himachal Pradesh. The transmission main is a 13 kilometres long pipe with 7.9 kilometres as pumping main and 5.1 kilometres as gravitational main. The analysis deals with mainly pumping mains. The results are available in two text files. Besides, several files are prepared with specific view to obtain results in a graphical form. These results help to observe the pressure difference and surge occurrence at different locations along the pipe profile, which help to redesign the transmission main with different but suitable safety measures against possible surge. A technically viable and economically feasible design has been provided as per the relevant manual and standard code of practice.Keywords: surge, water hammer, transmission mains, SAP 2000
Procedia PDF Downloads 4034835 One-Class Support Vector Machine for Sentiment Analysis of Movie Review Documents
Authors: Chothmal, Basant Agarwal
Abstract:
Sentiment analysis means to classify a given review document into positive or negative polar document. Sentiment analysis research has been increased tremendously in recent times due to its large number of applications in the industry and academia. Sentiment analysis models can be used to determine the opinion of the user towards any entity or product. E-commerce companies can use sentiment analysis model to improve their products on the basis of users’ opinion. In this paper, we propose a new One-class Support Vector Machine (One-class SVM) based sentiment analysis model for movie review documents. In the proposed approach, we initially extract features from one class of documents, and further test the given documents with the one-class SVM model if a given new test document lies in the model or it is an outlier. Experimental results show the effectiveness of the proposed sentiment analysis model.Keywords: feature selection methods, machine learning, NB, one-class SVM, sentiment analysis, support vector machine
Procedia PDF Downloads 5174834 Improvement in Acoustic Performance at Low Frequency via Application of Acoustic Resistance of Vented Hole in In-Ear Earphones
Authors: Tzu-Hsuan Lei, Shu-Chien Wu, Kuang-Che Lo, Shu-Chi Liu, Yu-Cheng Liu
Abstract:
The focus of this study was on the effects of air propagation associated with vented holes on acoustic resistance properties. A cylindrical hole with diameter and depth of 0.7 mm and 1.0 mm, respectively, was the research target. By constructing a finite element analytical model of its sound field properties, the acoustic-specific airflow resistance relationships were obtained for the differences in sound pressure and flow velocity at the two ends of this vented hole. In addition, the acoustic properties of this vented hole were included in the in-ear earphone simulation model to complete the sound pressure curve simulation analysis of the in-ear earphone system with a vented hole of corresponding size. Then, the simulation results were compared with actual measurements obtained from the standard system. Based on the results, when the in-ear earphone vented hole simulation model considered the simulated specific airflow resistance values of this cylindrical hole, the overall simulated sound pressure performance was highly consistent with that of measured values. The difference in the first peak values of sound pressure at mid-to-low frequencies was reduced from 5.64% when the simulation model did not consider the specific airflow resistance of the cylindrical hole to 1.18%, and the accuracy of the overall simulation was around 70%. This indicates the importance of the acoustic resistance properties of vented holes. Moreover, as specific airflow resistance values were able to be further quantified, the accuracy of the entire in-ear earphone simulation was ultimately and effectively elevated.Keywords: specific airflow resistance, vented holes, in-ear earphone, finite element method
Procedia PDF Downloads 434833 Semi-Supervised Outlier Detection Using a Generative and Adversary Framework
Authors: Jindong Gu, Matthias Schubert, Volker Tresp
Abstract:
In many outlier detection tasks, only training data belonging to one class, i.e., the positive class, is available. The task is then to predict a new data point as belonging either to the positive class or to the negative class, in which case the data point is considered an outlier. For this task, we propose a novel corrupted Generative Adversarial Network (CorGAN). In the adversarial process of training CorGAN, the Generator generates outlier samples for the negative class, and the Discriminator is trained to distinguish the positive training data from the generated negative data. The proposed framework is evaluated using an image dataset and a real-world network intrusion dataset. Our outlier-detection method achieves state-of-the-art performance on both tasks.Keywords: one-class classification, outlier detection, generative adversary networks, semi-supervised learning
Procedia PDF Downloads 1514832 From Sound to Music: The Trajectory of Musical Semiotics in a Selected Soundscape Environment in South-Western Nigeria
Authors: Olatunbosun Samuel Adekogbe
Abstract:
This paper addresses the question of musical signification, revolving around nature and its natural divides; the paper tends to examine the roles of the dispositional apparatus of listeners to react to sounding environments through music as coordinated sound that focuses on the powerful strain between vibrational occurrences of sound and potentials of being structured. This paper sets out to examine music as a simple conventional design that does not allude to something beyond music and sound as a vehicle to communicate through production, perception, translation, and reaction with regard to melodic and semiotic functions of sounds. This paper adopts the application of questionnaire and evolutionary approach methods to probe musical adaptation, reproduction, and natural selection as the basis for explaining specific human behavioural responses to musical sense-making beyond the above-sketched dichotomies, with a major focus on the transition from acoustic-emotional sensibilities to musical meaning in the selected soundscapes. It was observed that music has emancipated itself from the level of mere acoustic processing of sounds to a functional description in terms of allowing music users to share experiences and interact with the soundscaping environment. The paper, therefore, concludes that the audience as music participants and listeners in the selected soundscapes have been conceived as adaptive devices in the paradigm shift, which can build up new semiotic linkages with the sounding environments in southwestern Nigeria.Keywords: semiotics, sound, music, soundscape, environment
Procedia PDF Downloads 654831 Effect of Parameters for Exponential Loads on Voltage Transmission Line with Compensation
Authors: Benalia Nadia, Bensiali Nadia, Zerzouri Noura
Abstract:
This paper presents an analysis of the effects of parameters np and nq for exponential load on the transmission line voltage profile, transferred power and transmission losses for different shunt compensation size. For different values for np and nq in which active and reactive power vary with it is terminal voltages as in exponential form, variations of the load voltage for different sizes of shunt capacitors are simulated with a simple two-bus power system using Matlab SimPowerSystems Toolbox. It is observed that the compensation level is significantly affected by the voltage sensitivities of loads.Keywords: static load model, shunt compensation, transmission system, exponentiel load model
Procedia PDF Downloads 3684830 Class Size Effects on Reading Achievement in Europe: Evidence from Progress in International Reading Literacy Study
Authors: Ting Shen, Spyros Konstantopoulos
Abstract:
During the past three decades, class size effects have been a focal debate in education. The idea of having smaller class is enormously popular among parents, teachers and policy makers. The rationale of its popularity is that small classroom could provide a better learning environment in which there would be more teacher-pupil interaction and more individualized instruction. This early stage benefits would also have a long-term positive effect. It is a common belief that reducing class size may result in increases in student achievement. However, the empirical evidence about class-size effects from experimental or quasi-experimental studies has been mixed overall. This study sheds more light on whether class size reduction impacts reading achievement in eight European countries: Bulgaria, Germany, Hungary, Italy, Lithuania, Romania, Slovakia, and Slovenia. We examine class size effects on reading achievement using national probability samples of fourth graders. All eight European countries had participated in the Progress in International Reading Literacy Study (PIRLS) in 2001, 2006 and 2011. Methodologically, the quasi-experimental method of instrumental variables (IV) has been utilized to facilitate causal inference of class size effects. Overall, the results indicate that class size effects on reading achievement are not significant across countries and years. However, class size effects are evident in Romania where reducing class size increases reading achievement. In contrast, in Germany, increasing class size seems to increase reading achievement. In future work, it would be valuable to evaluate differential class size effects for minority or economically disadvantaged student groups or low- and high-achievers. Replication studies with different samples and in various settings would also be informative. Future research should continue examining class size effects in different age groups and countries using rich international databases.Keywords: class size, reading achievement, instrumental variables, PIRLS
Procedia PDF Downloads 2904829 Class-Size and Instructional Materials as Correlates of Pupils Learning and Academic Achievement in Primary School
Authors: Aanuoluwapo Olusola Adesanya, Adesina Joseph
Abstract:
This paper examined the class-size and instructional materials as correlates of pupils learning and academic achievement in primary school. The population of the study comprised 198 primary school pupils in three selected schools in Ogun State, Nigeria. Data were collected through questionnaire and were analysed with the use of multiple regression and ANOVA to analysed the correlation between class-size, instructional materials (independent variables) and learning achievement (dependent variable). The findings revealed that schools having an average class-size of 30 and below with use of instructional materials obtained better results than schools having more than 30 and above. The main score were higher in the school in schools having 30 and below than schools with 30 and above. It was therefore recommended that government, stakeholders and NGOs should provide more classrooms and supply of adequate instructional materials in all primary schools in the state to cater for small class-size.Keywords: class-size, instructional materials, learning, academic achievement
Procedia PDF Downloads 3504828 Influence of Power Flow Controller on Energy Transaction Charges in Restructured Power System
Authors: Manisha Dubey, Gaurav Gupta, Anoop Arya
Abstract:
The demand for power supply increases day by day in developing countries like India henceforth demand of reactive power support in the form of ancillary services provider also has been increased. The multi-line and multi-type Flexible alternating current transmission system (FACTS) controllers are playing a vital role to regulate power flow through the transmission line. Unified power flow controller and interline power flow controller can be utilized to control reactive power flow through the transmission line. In a restructured power system, the demand of such controller is being popular due to their inherent capability. The transmission pricing by using reactive power cost allocation through modified matrix methodology has been proposed. The FACTS technologies have quite costly assembly, so it is very useful to apportion the expenses throughout the restructured electricity industry. Therefore, in this work, after embedding the FACTS devices into load flow, the impact on the costs allocated to users in fraction to the transmission framework utilization has been analyzed. From the obtained results, it is clear that the total cost recovery is enhanced towards the Reactive Power flow through the different transmission line for 5 bus test system. The fair pricing policy towards reactive power can be achieved by the proposed method incorporating FACTS controller towards cost recovery of the transmission network.Keywords: interline power flow controller, transmission pricing, unified power flow controller, cost allocation
Procedia PDF Downloads 1484827 Analysis of Exponential Nonuniform Transmission Line Parameters
Authors: Mounir Belattar
Abstract:
In this paper the Analysis of voltage waves that propagate along a lossless exponential nonuniform line is presented. For this analysis the parameters of this line are assumed to be varying function of the distance x along the line from the source end. The approach is based on the tow-port networks cascading presentation to derive the ABDC parameters of transmission using Picard-Carson Method which is a powerful method in getting a power series solution for distributed network because it is easy to calculate poles and zeros and solves differential equations such as telegrapher equations by an iterative sequence. So the impedance, admittance voltage and current along the line are expanded as a Taylor series in x/l where l is the total length of the line to obtain at the end, the main transmission line parameters such as voltage response and transmission and reflexion coefficients represented by scattering parameters in frequency domain.Keywords: ABCD parameters, characteristic impedance exponential nonuniform transmission line, Picard-Carson's method, S parameters, Taylor's series
Procedia PDF Downloads 4434826 Enhance Power Quality by HVDC System, Comparison Technique between HVDC and HVAC Transmission Systems
Authors: Smko Zangana, Ergun Ercelebi
Abstract:
The alternating current is the main power in all industries and other aspects especially for the short and mid distances, but as far as long a distance which exceeds 500 KMs, using the alternating current technically will face many difficulties and more costs because it's difficult to control the current and also other restrictions. Therefore, recently those reasons led to building transmission lines HVDC to transmit power for long distances. This document presents technical comparison and assessments for power transmission system among distances either ways and studying the stability of the system regarding the proportion of losses in the actual power sent and received between both sides in different systems and also categorizing filters used in the HVDC system and its impact and effect on reducing Harmonic in the power transmission. MATLAB /Simulink simulation software is used to simulate both HVAC & HVDC power transmission system topologies.Keywords: HVAC power system, HVDC power system, power system simulation (MATLAB), the alternating current, voltage stability
Procedia PDF Downloads 3664825 Inverse Scattering for a Second-Order Discrete System via Transmission Eigenvalues
Authors: Abdon Choque-Rivero
Abstract:
The Jacobi system with the Dirichlet boundary condition is considered on a half-line lattice when the coefficients are real valued. The inverse problem of recovery of the coefficients from various data sets containing the so-called transmission eigenvalues is analyzed. The Marchenko method is utilized to solve the corresponding inverse problem.Keywords: inverse scattering, discrete system, transmission eigenvalues, Marchenko method
Procedia PDF Downloads 144