Search results for: software defined radios
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7535

Search results for: software defined radios

4745 Research of Control System for Space Intelligent Robot Based on Vision Servo

Authors: Changchun Liang, Xiaodong Zhang, Xin Liu, Pengfei Sun

Abstract:

Space intelligent robotic systems are expected to play an increasingly important role in the future. The robotic on-orbital service, whose key is the tracking and capturing technology, becomes research hot in recent years. In this paper, the authors propose a vision servo control system for target capturing. Robotic manipulator will be an intelligent robotic system with large-scale movement, functional agility, and autonomous ability, and it can be operated by astronauts in the space station or be controlled by the ground operator in the remote operation mode. To realize the autonomous movement and capture mission of SRM, a kind of autonomous programming strategy based on multi-camera vision fusion is designed and the selection principle of object visual position and orientation measurement information is defined for the better precision. Distributed control system hierarchy is designed and reliability is considering to guarantee the abilities of control system. At last, a ground experiment system is set up based on the concept of robotic control system. With that, the autonomous target capturing experiments are conducted. The experiment results validate the proposed algorithm, and demonstrates that the control system can fulfill the needs of function, real-time and reliability.

Keywords: control system, on-orbital service, space robot, vision servo

Procedia PDF Downloads 422
4744 Pubertal Development among 10-Year-Olds: The Role of Parent's Attachment Style

Authors: Hanit Ohana, Anat Scher

Abstract:

For decades, attachment research examined how mothers’ attachment styles shape parenting and specific aspects of child development. Only limited research addressed pubertal development from the perspective of attachment relationships. The current study focused on pubertal development at 10 years of age, as defined by Tanner (PDS), and examined the associations with both mothers’ and fathers’ attachment styles (ECR-S). Sixty-nine parents and their children from a medium SES participated in the study. It was found that whereas mothers’ attachment was not related to the child’s puberty development, fathers’ attachment was associated with their daughter’s pubertal development. Specifically, in girls, but not boys, advanced pubertal development was positively correlated with fathers’ avoidance (r = .37, p = 0.05), and negatively correlated with anxiety scores (r = -.36, p = 0.05). This result raises the possibility that for girls, a relationship with fathers may serve as a psychological stressor, and in turn, induce concerns regarding resources and availability of interpersonal support. Such processes may contribute to different reproductive timing and strategies, including delayed and accelerated pubertal development. As more data are collected, we will be able to address with more power the role of parent’s attachment in shaping the pubertal development of their young adolescents. Expanding the understanding of aspects of pubertal development –an important milestone of human development- and the possible linkages with parental attachment is important for researchers and clinicians.

Keywords: attachment style, children, gender, parents, puberty

Procedia PDF Downloads 147
4743 Structural Analysis of Hydro-Turbine Head Cover Using Ansys

Authors: Surjit Angra, Manisha Kumari, Vinod Kumar

Abstract:

The objective of the Hydro Turbine Head Cover is to support the guide bearing, guide vane regulating mechanism and even in some design for generator thrust bearing support. Mechanical design of head cover deals with high static as well as fluctuating load acting on the structure. In the present work structural analysis of hydro turbine Head-cover using ANSYS software is carried out. Finite element method is used to calculate stresses on head cover. These calculations were done for the maximum possible loading under operating condition “LCI Quick Shut Down”. The results for equivalent Von-Mises stress, total deformation and directional deformation have been plotted and compared with the existing results whether the design is safe or not.

Keywords: ANSYS, head cover, hydro-turbine, structural analysis, total deformation, Von-Mises stress

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4742 Numerical Modeling for Water Engineering and Obstacle Theory

Authors: Mounir Adal, Baalal Azeddine, Afifi Moulay Larbi

Abstract:

Numerical analysis is a branch of mathematics devoted to the development of iterative matrix calculation techniques. We are searching for operations optimization as objective to calculate and solve systems of equations of order n with time and energy saving for computers that are conducted to calculate and analyze big data by solving matrix equations. Furthermore, this scientific discipline is producing results with a margin of error of approximation called rates. Thus, the results obtained from the numerical analysis techniques that are held on computer software such as MATLAB or Simulink offers a preliminary diagnosis of the situation of the environment or space targets. By this we can offer technical procedures needed for engineering or scientific studies exploitable by engineers for water.

Keywords: numerical analysis methods, obstacles solving, engineering, simulation, numerical modeling, iteration, computer, MATLAB, water, underground, velocity

Procedia PDF Downloads 466
4741 Challenges and Opportunities of Cloud-Based E-Learning Systems

Authors: Kashif Laeeq, Zubair A. Shaikh

Abstract:

The paradigm of education is drastically changing from conventional to e-learning model. Due to ease of learning with various other benefits, several educational institutions are adopting the e-learning models. Some institutions are still willing to transform their educational system on to e-learning, but due to limited resources, they are still compromising on the old traditional system. The cloud computing could be one of the best solutions to overcome this problem by providing hardware, software, and infrastructure resources with cost efficient manner. The adoption of cloud computing in education will bring revolution in this paradigm. This paper introduces various positive features of e-learning and presents a way how cloud computing technology can be provisioned e-learning model. This paper also investigates the numerous challenges and opportunities that would be observed in cloud computing adoption in e-learning domain. The concept and knowledge present in this paper may create a new direction of research in the domain of cloud-based e-learning.

Keywords: cloud-based e-learning, e-learning, cloud computing application, smart learning

Procedia PDF Downloads 412
4740 The Effect of Electronic Platform Service Usage on Customer Satisfaction and WOM

Authors: Shui Lien Chen, Yi-Fen Tsai, Jim Shih-Chiao Chin

Abstract:

—In this study, using Chunghwa Telecom as a case. The company accounted for the highest proportion of the telecommunications company in Taiwan. First, this paper would like to understand the effect of convenience performance on perceived ease of use and perceived usefulness. Further, the perceived ease of use and perceived usefulness of Technology Acceptance Model (TAM) are adopted as the factors on the company's brand perception. Afterward, the brand perception influence on customer satisfaction, and finally whether producing a good reputation and recommendation are tested. The study participants are people who have used electronic platform service of Chunghwa Telecom. A total of 478 valid questionnaires were used and AMOS 20.0 statistical software programs were adopted to analyze.

Keywords: technology acceptance model, brand association, brand awareness, brand attachment, customer satisfaction, word-of-mouth (WOM)

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4739 The Influence of Variable Geometrical Modifications of the Trailing Edge of Supercritical Airfoil on the Characteristics of Aerodynamics

Authors: P. Lauk, K. E. Seegel, T. Tähemaa

Abstract:

The fuel consumption of modern, high wing loading, commercial aircraft in the first stage of flight is high because the usable flight level is lower and the weather conditions (jet stream) have great impact on aircraft performance. To reduce the fuel consumption, it is necessary to raise during first stage of flight the L/D ratio value within Cl 0.55-0.65. Different variable geometrical wing trailing edge modifications of SC(2)-410 airfoil were compared at M 0.78 using the CFD software STAR-CCM+ simulation based Reynolds-averaged Navier-Stokes (RANS) equations. The numerical results obtained show that by increasing the width of the airfoil by 4% and by modifying the trailing edge airfoil, it is possible to decrease airfoil drag at Cl 0.70 for up to 26.6% and at the same time to increase commercial aircraft L/D ratio for up to 5.0%. Fuel consumption can be reduced in proportion to the increase in L/D ratio.

Keywords: L/D ratio, miniflaps, mini-TED, supercritical airfoil

Procedia PDF Downloads 211
4738 Ergonomic Design of Speed Control Humps/Dips

Authors: Emad Khorshid, Habib Awada

Abstract:

Newly developed Ergonomic speed control hump/Dip designs are conducted. The numerical simulation for the driver-vehicle-hump dynamic system will be performed using computer software. The design problem for which the speed hump or dip should provide: (1) discomfort feeling to the driver if speed is over the specified limit, and (2) normal/good comfort level to the driver (and or other passengers) if the speed is within the limit. For comparison reasons, different vehicles suspension systems (active, semi-active and non-active suspension) are used in the simulation. The measuring of the acceptable range of vibration will be referenced to the British standard BS6841, ISO 2631/1 and the new ISO 2631/5. All these standards are related to human health and comfort level in terms of acceptable range of whole body vibration exposure.

Keywords: speed hump, speed dip, ergonomic design, human health, vehicle modeling

Procedia PDF Downloads 375
4737 Using Scilab® as New Introductory Method in Numerical Calculations and Programming for Computational Fluid Dynamics (CFD)

Authors: Nicoly Coelho, Eduardo Vieira Vilas Boas, Paulo Orestes Formigoni

Abstract:

Faced with the remarkable developments in the various segments of modern engineering, provided by the increasing technological development, professionals of all educational areas need to overcome the difficulties generated due to the good understanding of those who are starting their academic journey. Aiming to overcome these difficulties, this article aims at an introduction to the basic study of numerical methods applied to fluid mechanics and thermodynamics, demonstrating the modeling and simulations with its substance, and a detailed explanation of the fundamental numerical solution for the use of finite difference method, using SCILAB, a free software easily accessible as it is free and can be used for any research center or university, anywhere, both in developed and developing countries. It is known that the Computational Fluid Dynamics (CFD) is a necessary tool for engineers and professionals who study fluid mechanics, however, the teaching of this area of knowledge in undergraduate programs faced some difficulties due to software costs and the degree of difficulty of mathematical problems involved in this way the matter is treated only in postgraduate courses. This work aims to bring the use of DFC low cost in teaching Transport Phenomena for graduation analyzing a small classic case of fundamental thermodynamics with Scilab® program. The study starts from the basic theory involving the equation the partial differential equation governing heat transfer problem, implies the need for mastery of students, discretization processes that include the basic principles of series expansion Taylor responsible for generating a system capable of convergence check equations using the concepts of Sassenfeld, finally coming to be solved by Gauss-Seidel method. In this work we demonstrated processes involving both simple problems solved manually, as well as the complex problems that required computer implementation, for which we use a small algorithm with less than 200 lines in Scilab® in heat transfer study of a heated plate in rectangular shape on four sides with different temperatures on either side, producing a two-dimensional transport with colored graphic simulation. With the spread of computer technology, numerous programs have emerged requiring great researcher programming skills. Thinking that this ability to program DFC is the main problem to be overcome, both by students and by researchers, we present in this article a hint of use of programs with less complex interface, thus enabling less difficulty in producing graphical modeling and simulation for DFC with an extension of the programming area of experience for undergraduates.

Keywords: numerical methods, finite difference method, heat transfer, Scilab

Procedia PDF Downloads 388
4736 Banking Performance and Political Economy: Using ARDL Model

Authors: Marwen Ghouil, Jamel Eddine Mkadmi

Abstract:

Banking performance is the pillar and goal of all banking activity and its impact on economic policy. First, researchers defined the principles for assessing and modeling bank performance, and then theories and models explaining bank performance were developed. The importance of credit as a means of financing businesses in most developing countries has led to questions about the effects of financial liberalisation on increased banking competition. In Tunisia, as in many other countries, the liberalization of financial services in general and of banks' activities has not ceased to evolve. The objective of this paper is to examine the determinants of banking performance for 8 Tunisian banks and their impact on economic policy during the Arab Spring. We used cointegration analysis and the ARDL Panel model, explaining using total assets, bank credits, guarantees, and bank size as performance drivers. The correlation analysis shows that there is a positive correlation relationship between total assets, bank credits, guarantees, and bank size and bank performance. Long-term empirical results show that bank loans, guarantees, bank size, and total assets have a positive and significant impact on bank performance. This means that bank credits, guarantees, bank size, and total assets are very important determinants of bank performance in Tunisia.

Keywords: bank performance, economic policy, finance, economic

Procedia PDF Downloads 142
4735 Disability in the Course of a Chronic Disease: The Example of People Living with Multiple Sclerosis in Poland

Authors: Milena Trojanowska

Abstract:

Disability is a phenomenon for which meanings and definitions have evolved over the decades. This became the trigger to start a project to answer the question of what disability constitutes in the course of an incurable chronic disease. The chosen research group are people living with multiple sclerosis.The contextual phase of the research was participant observation at the Polish Multiple Sclerosis Society, the largest NGO in Poland supporting people living with MS and their relatives. The research techniques used in the project are (in order of implementation): group interviews with people living with MS and their relatives, narrative interviews, asynchronous technique, participant observation during events organised for people living with MS and their relatives.The researcher is currently conducting follow-up interviews, as inaccuracies in the respondents' narratives were identified during the data analysis. Interviews and supplementary research techniques were used over the four years of the research, and the researcher also benefited from experience gained from 12 years of working with NGOs (diaries, notes). The research was carried out in Poland with the participation of people living in this country only.The research has been based on grounded theory methodology in a constructivist perspectivedeveloped by Kathy Charmaz. The goal was to follow the idea that research must be reliable, original, and useful. The aim was to construct an interpretive theory that assumes temporality and the processualityof social life. TheAtlas.ti software was used to collect research material and analyse it. It is a program from the CAQDAS(Computer-Assisted Qualitative Data Analysis Software) group.Several key factors influencing the construction of a disability identity by people living with multiple sclerosis was identified:-course of interaction with significant relatives,- the expectation of identification with disability (expressed by close relatives),- economic profitability (pension, allowances),- institutional advantages (e.g. parking card),- independence and autonomy (not equated with physical condition, but access to adapted infrastructure and resources to support daily functioning),- the way a person with MS construes the meaning of disability,- physical and mental state,- medical diagnosis of illness.In addition, it has been shown that making an assumption about the experience of disability in the course of MS is a form of cognitive reductionism leading to further phenomenon such as: the expectation of the person with MS to construct a social identity as a person with a disability (e.g. giving up work), the occurrence of institutional inequalities. It can also be a determinant of the choice of a life strategy that limits social and individual functioning, even if this necessity is not influenced by the person's physical or psychological condition.The results of the research are important for the development of knowledge about the phenomenon of disability. It indicates the contextuality and complexity of the disability phenomenon, which in the light of the research is a set of different phenomenon of heterogeneous nature and multifaceted causality. This knowledge can also be useful for institutions and organisations in the non-governmental sector supporting people with disabilities and people living with multiple sclerosis.

Keywords: disability, multiple sclerosis, grounded theory, poland

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4734 Design, Development by Functional Analysis in UML and Static Test of a Multimedia Voice and Video Communication Platform on IP for a Use Adapted to the Context of Local Businesses in Lubumbashi

Authors: Blaise Fyama, Elie Museng, Grace Mukoma

Abstract:

In this article we present a java implementation of video telephony using the SIP protocol (Session Initiation Protocol). After a functional analysis of the SIP protocol, we relied on the work of Italian researchers of University of Parma-Italy to acquire adequate libraries for the development of our own communication tool. In order to optimize the code and improve the prototype, we used, in an incremental approach, test techniques based on a static analysis based on the evaluation of the complexity of the software with the application of metrics and the number cyclomatic of Mccabe. The objective is to promote the emergence of local start-ups producing IP video in a well understood local context. We have arrived at the creation of a video telephony tool whose code is optimized.

Keywords: static analysis, coding complexity metric mccabe, Sip, uml

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4733 Investigating Message Timing Side Channel Attacks on Networks on Chip with Ring Topology

Authors: Mark Davey

Abstract:

Communications on a Network on Chip (NoC) produce timing information, i.e., network injection delays, packet traversal times, throughput metrics, and other attributes relating to the traffic being sent across the chip. The security requirements of a platform encompass each node to operate with confidentiality, integrity, and availability (ISO 27001). Inherently, a shared NoC interconnect is exposed to analysis of timing patterns created by contention for the network components, i.e., links and switches/routers. This phenomenon is defined as information leakage, which represents a ‘side channel’ of sensitive information that can be correlated to platform activity. The key algorithm presented in this paper evaluates how an adversary can control two platform neighbouring nodes of a target node to obtain sensitive information about communication with the target node. The actual information obtained is the period value of a periodic task communication. This enacts a breach of the expected confidentiality of a node operating in a multiprocessor platform. An experimental investigation of the side channel is undertaken to judge the level and significance of inferred information produced by access times to the NoC. Results are presented with a series of expanding task set scenarios to evaluate the efficacy of the side channel detection algorithm as the network load increases.

Keywords: embedded systems, multiprocessor, network on chip, side channel

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4732 Technology, Organizational and Environmental Determinants of Business Intelligence Systems Adoption in Croatian SME: A Case Study of Medium-Sized Enterprise

Authors: Ana-Marija Stjepić, Luka Sušac, Dalia Suša Vugec

Abstract:

In the last few years, examples from scientific literature and business practices show that the adoption of technological innovations increases enterprises' performance. Recently, when it comes to the field of information technology innovation, business intelligence systems (BISs) have drawn a significant amount of attention of the scientific circles. BISs can be understood as a form of technological innovation which can bring certain benefits to the organizations that are adopting it. Therefore, the aim of this paper is twofold: (1) to define determinants of successful BISs adoption in small and medium enterprises and thus contribute to this neglected research area and (2) to present the current state of BISs adoption in small and medium-sized companies. In order to do so, determinants are defined and classified into three dimensions, according to the Technology – Organization – Environment (TOE) theoretical framework that describes the impact of each dimension on technological innovations adoption. Moreover, paper brings a case study presenting the adoption of BISs in practice within an organization from tertiary (service) industry sector. Based on the results of the study, guidelines for more efficient, faster and easier BISs adoption are presented.

Keywords: adoption, business intelligence, business intelligence systems, case study, TOE framework

Procedia PDF Downloads 153
4731 Children and Parents Left behind in Transnational Families: The Problem of Care Deficit

Authors: Joanna Bielecka-Prus

Abstract:

In the view of increasing number of labour migrations associated with broadly understood economic crisis, many families experience migration separation. Currently, in the era of globalization, migration movements include an increasing number of families, more and more frequently a new type of family, a transnational family. Accordingly, the functions of the family, family practice of care, and the relationships between members of the group change especially in the case of female migration. Sociologists highlight the emotional aspects of migrants’ family lives: managing emotions, coping with guilt, loneliness and rejection. Not without significance is the fact that today's public discourse often represents migrant women in a negative light. On the one hand, consumption and expanding material resources are assessed positively, on the other hand, deficits emotional and devastation of family life in the transnational families appear. Opinions expressed by different environments: the media, the political environment, etc. do not always take into account the context of mobility and their different effects on family life. The paper will present the analysis of qualitative studies of Polish female migrants’ families left-behind (children, parents, caregivers N = 100) and their coping strategies in different situations in the event of migration separation. The main area of care deficit will be defined and it will be showed who and how help to solve the problems.

Keywords: care, children left behind, female migration, parents left behind

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4730 Challenging the Theory of Mind: Autism Spectrum Disorder, Social Construction, and Biochemical Explanation

Authors: Caroline Kim

Abstract:

The designation autism spectrum disorder (ASD) groups complex disorders in the development of the brain. Autism is defined essentially as a condition in which an individual lacks a theory of mind. The theory of mind, in this sense, explains the ability of an individual to attribute feelings, emotions, or thoughts to another person. An autistic patient is characteristically unable to determine what an interlocutor is feeling, or to understand the beliefs of others. However, it is possible that autism cannot plausibly characterized as the lack of theory of mind in an individual. Genes, the bran, and its interplay with environmental factors may also cause autism. A mutation in a gene may be hereditary, or instigated by diseases such as mumps. Though an autistic patient may experience abnormalities in the cerebellum and the cortical regions, these are in fact only possible theories as to a biochemical explanation behind the disability. The prevailing theory identifying autism with lacking the theory of mind is supported by behavioral observation, but this form of observation is itself determined by socially constructed standards, limiting the possibility for empirical verification. The theory of mind infers that the beliefs and emotions of people are causally based on their behavior. This paper demonstrates the fallacy of this inference, critiquing its basis in socially constructed values, and arguing instead for a biochemical approach free from the conceptual apparatus of language and social expectation.

Keywords: autism spectrum disorder, sociology of psychology, social construction, the theory of mind

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4729 Use of Machine Learning in Data Quality Assessment

Authors: Bruno Pinto Vieira, Marco Antonio Calijorne Soares, Armando Sérgio de Aguiar Filho

Abstract:

Nowadays, a massive amount of information has been produced by different data sources, including mobile devices and transactional systems. In this scenario, concerns arise on how to maintain or establish data quality, which is now treated as a product to be defined, measured, analyzed, and improved to meet consumers' needs, which is the one who uses these data in decision making and companies strategies. Information that reaches low levels of quality can lead to issues that can consume time and money, such as missed business opportunities, inadequate decisions, and bad risk management actions. The step of selecting, identifying, evaluating, and selecting data sources with significant quality according to the need has become a costly task for users since the sources do not provide information about their quality. Traditional data quality control methods are based on user experience or business rules limiting performance and slowing down the process with less than desirable accuracy. Using advanced machine learning algorithms, it is possible to take advantage of computational resources to overcome challenges and add value to companies and users. In this study, machine learning is applied to data quality analysis on different datasets, seeking to compare the performance of the techniques according to the dimensions of quality assessment. As a result, we could create a ranking of approaches used, besides a system that is able to carry out automatically, data quality assessment.

Keywords: machine learning, data quality, quality dimension, quality assessment

Procedia PDF Downloads 154
4728 Model Based Development of a Processing Map for Friction Stir Welding of AA7075

Authors: Elizabeth Hoyos, Hernán Alvarez, Diana Lopez, Yesid Montoya

Abstract:

The main goal of this research relates to the modeling of FSW from a different or unusual perspective coming from mechanical engineering, particularly looking for a way to establish process windows by assessing soundness of the joints as a priority and with the added advantage of lower computational time. This paper presents the use of a previously developed model applied to specific aspects of soundness evaluation of AA7075 FSW welds. EMSO software (Environment for Modeling, Simulation, and Optimization) was used for simulation and an adapted CNC machine was used for actual welding. This model based approach showed good agreement with the experimental data, from which it is possible to set a window of operation for commercial aluminum alloy AA7075, all with low computational costs and employing simple quality indicators that can be used by non-specialized users in process modeling.

Keywords: aluminum AA7075, friction stir welding, phenomenological based semiphysical model, processing map

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4727 Audience Perceptions and Attitudes Towards the Representation of Tribal South African Culture in Drama Series

Authors: Oluwayemisi Mary Onyenanakeya, Kevin Onyenankeya

Abstract:

Commercial media entertainment offerings especially mainstream soap operas, in South Africa, are progressively infusing dominant social values and ideas which are alien to South African tribal societies. In most of the commodified television drama series, people who hold tight to traditional beliefs and values are often characterised as traditionalists, while those who have imbibed the western defined dicta and ideology of modernity are seen as progressives. This study, therefore, sought to ascertain how South African tribal language, traditional institutions, values, social norms and ancestral beliefs are portrayed through the television drama, Generations: The Legacy, and what the viewers think about those constructions and the implication for cultural identity. The mixed methods approach was employed involving the administration of questionnaire to 350 participants selected through random sampling and a content analysis of 20 episodes of Generations: The Legacy. The findings further showed that the values and traditions represented in generation do not significantly reflect the South African tribal tradition and values (p-value > 0.05). In most instances where traditional values are represented they tend to be portrayed as old fashioned (p-value > 0.05), and inferior and backward (p-value > 0.05). In addition, the findings indicate that Generations: The legacy is a vehicle for promoting dominant culture.

Keywords: identity, soap opera, South Africa, television

Procedia PDF Downloads 291
4726 Development of Value Based Planning Methodology Incorporating Risk Assessment for Power Distribution Network

Authors: Asnawi Mohd Busrah, Au Mau Teng, Tan Chin Hooi, Lau Chee Chong

Abstract:

This paper describes value based planning (VBP) methodology incorporating risk assessment as an enhanced and more practical approach to evaluate distribution network projects in Peninsular Malaysia. Assessment indicators associated with economics, performance and risks are formulated to evaluate distribution projects to quantify their benefits against investment. The developed methodology is implemented in a web-based software customized to capture investment and network data, compute assessment indicators and rank the proposed projects according to their benefits. Value based planning approach addresses economic factors in the power distribution planning assessment, so as to minimize cost solution to the power utility while at the same time provide maximum benefits to customers.

Keywords: value based planning, distribution network, value of loss load (VoLL), energy not served (ENS)

Procedia PDF Downloads 483
4725 A Bibliometric Analysis of Research on E-learning in Physics Education: Trends, Patterns, and Future Directions

Authors: Siti Nurjanah, Supahar

Abstract:

E-learning has become an increasingly popular mode of instruction, particularly in the field of physics education, where it offers opportunities for interactive and engaging learning experiences. This research aims to analyze the trends of research that investigated e-learning in physics education. Data was extracted from Scopus's database using the keywords "physics" and "e-learning". Of the 380 articles obtained based on the search criteria, a trend analysis of the research was carried out with the help of RStudio using the biblioshiny package and VosViewer software. Analysis showed that publications on this topic have increased significantly from 2014 to 2021. The publication was dominated by researchers from the United States. The main journal that publishes articles on this topic is Proceedings Frontiers in Education Conference fie. The most widely cited articles generally focus on the effectiveness of Moodle for physics learning. Overall, this research provides an in-depth understanding of the trends and key findings of research related to e-learning in physics.

Keywords: bibliometric analysis, physics education, biblioshiny, E-learning

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4724 Different Sampling Schemes for Semi-Parametric Frailty Model

Authors: Nursel Koyuncu, Nihal Ata Tutkun

Abstract:

Frailty model is a survival model that takes into account the unobserved heterogeneity for exploring the relationship between the survival of an individual and several covariates. In the recent years, proposed survival models become more complex and this feature causes convergence problems especially in large data sets. Therefore selection of sample from these big data sets is very important for estimation of parameters. In sampling literature, some authors have defined new sampling schemes to predict the parameters correctly. For this aim, we try to see the effect of sampling design in semi-parametric frailty model. We conducted a simulation study in R programme to estimate the parameters of semi-parametric frailty model for different sample sizes, censoring rates under classical simple random sampling and ranked set sampling schemes. In the simulation study, we used data set recording 17260 male Civil Servants aged 40–64 years with complete 10-year follow-up as population. Time to death from coronary heart disease is treated as a survival-time and age, systolic blood pressure are used as covariates. We select the 1000 samples from population using different sampling schemes and estimate the parameters. From the simulation study, we concluded that ranked set sampling design performs better than simple random sampling for each scenario.

Keywords: frailty model, ranked set sampling, efficiency, simple random sampling

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4723 Effect of Preloading on Long-Term Settlement of Closed Landfills: A Numerical Analysis

Authors: Mehrnaz Alibeikloo, Hajar Share Isfahani, Hadi Khabbaz

Abstract:

In recent years, by developing cities and increasing population, reconstructing on closed landfill sites in some regions is unavoidable. Long-term settlement is one of the major concerns associated with reconstruction on landfills after closure. The purpose of this research is evaluating the effect of preloading in various patterns of height and time on long-term settlements of closed landfills. In this regard, five scenarios of surcharge from 1 to 3 m high within 3, 4.5 and 6 months of preloading time have been modeled using PLAXIS 2D software. Moreover, the numerical results have been compared to those obtained from analytical methods, and a good agreement has been achieved. The findings indicate that there is a linear relationship between settlement and surcharge height. Although, long-term settlement decreased by applying a longer and higher preloading, the time of preloading was found to be a more effective factor compared to preloading height.

Keywords: preloading, long-term settlement, landfill, PLAXIS 2D

Procedia PDF Downloads 198
4722 Influence of Building Orientation and Post Processing Materials on Mechanical Properties of 3D-Printed Parts

Authors: Raf E. Ul Shougat, Ezazul Haque Sabuz, G. M. Najmul Quader, Monon Mahboob

Abstract:

Since there are lots of ways for building and post processing of parts or models in 3D printing technology, the main objective of this research is to provide an understanding how mechanical characteristics of 3D printed parts get changed for different building orientations and infiltrates. Tensile, compressive, flexure, and hardness test were performed for the analysis of mechanical properties of those models. Specimens were designed in CAD software, printed on Z-printer 450 with five different build orientations and post processed with four different infiltrates. Results show that with the change of infiltrates or orientations each of the above mechanical property changes and for each infiltrate the highest tensile strength, flexural strength, and hardness are found for such orientation where there is the lowest number of layers while printing.

Keywords: 3D printing, building orientations, infiltrates, mechanical characteristics, number of layers

Procedia PDF Downloads 281
4721 Experimental and CFD of Desgined Small Wind Turbine

Authors: Tarek A. Mekail, Walid M. A. Elmagid

Abstract:

Many researches have concentrated on improving the aerodynamic performance of wind turbine blade through testing and theoretical studies. A small wind turbine blade is designed, fabricated and tested. The power performance of small horizontal axis wind turbines is simulated in details using Computational Fluid Dynamic (CFD). The three-dimensional CFD models are presented using ANSYS-CFX v13 software for predicting the performance of a small horizontal axis wind turbine. The simulation results are compared with the experimental data measured from a small wind turbine model, which designed according to a vehicle-based test system. The analysis of wake effect and aerodynamic of the blade can be carried out when the rotational effect was simulated. Finally, comparison between experimental, numerical and analytical performance has been done. The comparison is fairly good.

Keywords: small wind turbine, CFD of wind turbine, CFD, performance of wind turbine, test of small wind turbine, wind turbine aerodynamic, 3D model

Procedia PDF Downloads 546
4720 Stochastic Variation of the Hubble's Parameter Using Ornstein-Uhlenbeck Process

Authors: Mary Chriselda A

Abstract:

This paper deals with the fact that the Hubble's parameter is not constant and tends to vary stochastically with time. This premise has been proven by converting it to a stochastic differential equation using the Ornstein-Uhlenbeck process. The formulated stochastic differential equation is further solved analytically using the Euler and the Kolmogorov Forward equations, thereby obtaining the probability density function using the Fourier transformation, thereby proving that the Hubble's parameter varies stochastically. This is further corroborated by simulating the observations using Python and R-software for validation of the premise postulated. We can further draw conclusion that the randomness in forces affecting the white noise can eventually affect the Hubble’s Parameter leading to scale invariance and thereby causing stochastic fluctuations in the density and the rate of expansion of the Universe.

Keywords: Chapman Kolmogorov forward differential equations, fourier transformation, hubble's parameter, ornstein-uhlenbeck process , stochastic differential equations

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4719 The Charge Exchange and Mixture Formation Model in the ASz-62IR Radial Aircraft Engine

Authors: Pawel Magryta, Tytus Tulwin, Paweł Karpiński

Abstract:

The ASz62IR engine is a radial aircraft engine with 9 cylinders. This object is produced by the Polish company WSK "PZL-KALISZ" S.A. This is engine is currently being developed by the above company and Lublin University of Technology. In order to provide an effective work of the technological development of this unit it was decided to made the simulation model. The model of ASz-62IR was developed with AVL BOOST software which is a tool dedicated to the one-dimensional modeling of internal combustion engines. This model can be used to calculate parameters of an air and fuel flow in an intake system including charging devices as well as combustion and exhaust flow to the environment. The main purpose of this model is the analysis of the charge exchange and mixture formation in this engine. For this purpose, the model consists of elements such: as air inlet, throttle system, compressor connector, charging compressor, inlet pipes and injectors, outlet pipes, fuel injection and model of fuel mixing and evaporation. The model of charge exchange and mixture formation was based on the model of mass flow rate in intake and exhaust pipes, and also on the calculation of gas properties values like gas constant or thermal capacity. This model was based on the equations to describe isentropic flow. The energy equation to describe flow under steady conditions was transformed into the mass flow equation. In the model the flow coefficient μσ was used, that varies with the stroke/valve opening and was determined in a steady flow state. The geometry of the inlet channels and other key components was mapped with reference to the technical documentation of the engine and empirical measurements of the structure elements. The volume of elements on the charge flow path between the air inlet and the exhaust outlet was measured by the CAD mapping of the structure. Taken from the technical documentation, the original characteristics of the compressor engine was entered into the model. Additionally, the model uses a general model for the transport of chemical compounds of the mixture. There are 7 compounds used, i.e. fuel, O2, N2, CO2, H2O, CO, H2. A gasoline fuel of a calorific value of 43.5 MJ/kg and an air mass fraction for stoichiometric mixture of 14.5 were used. Indirect injection into the intake manifold is used in this model. The model assumes the following simplifications: the mixture is homogenous at the beginning of combustion, accordingly, mixture stoichiometric coefficient A/F remains constant during combustion, combusted and non-combusted charges show identical pressures and temperatures although their compositions change. As a result of the simulation studies based on the model described above, the basic parameters of combustion process, charge exchange, mixture formation in cylinders were obtained. The AVL Boost software is very useful for the piston engine performance simulations. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.

Keywords: aviation propulsion, AVL Boost, engine model, charge exchange, mixture formation

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4718 An Ecosystem Approach to Natural Resource Management: Case Study of the Topčiderska River, Serbia

Authors: Katarina Lazarević, Mirjana Todosijević, Tijana Vulević, Natalija Momirović, Ranka Erić

Abstract:

Due to increasing demand, climate change, and world population growth, natural resources are getting exploit fast. One of the most important natural resources is soil, which is susceptible to degradation. Erosion as one of the forms of land degradation is also one of the most global environmental problems. Ecosystem services are often defined as benefits that nature provides to humankind. Soil, as the foundation of basic ecosystem functions, provides benefits to people, erosion control, water infiltration, food, fuel, fibers… This research is using the ecosystem approach as a strategy for natural resources management for promoting sustainability and conservation. The research was done on the Topčiderska River basin (Belgrade, Serbia). The InVEST Sediment Delivery Ratio model was used, to quantify erosion intensity with a spatial distribution output map of overland sediment generation and delivery to the stream. InVEST SDR, a spatially explicit model, is using a method based on the concept of hydrological connectivity and (R) USLE model. This, combined with socio-economic and law and policy analysis, gives a full set of information to decision-makers helping them to successfully manage and deliver sustainable ecosystems.

Keywords: ecosystem services, InVEST model, soil erosion, sustainability

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4717 CNC Milling-Drilling Machine Cutting Tool Holder

Authors: Hasan Al Dabbas

Abstract:

In this paper, it is addressed that the mechanical machinery captures a major share of innovation in drilling and milling chucks technology. Users demand higher speeds in milling because they are cutting more aluminum and are relying on higher speeds to eliminate secondary finishing operations. To meet that demand, milling-machine builders have enhanced their machine’s rigidity. Moreover, faster cutting has caught up with boring mills. Cooling these machine’s internal components is a challenge at high speeds. Another trend predicted that it is more use of controlled axes to let the machines do many more operations on 5 sides without having to move or re-fix the work. Advances of technology in mechanical engineering have helped to make high-speed machining equipment. To accompany these changes in milling and drilling machines chucks, the demand of easiest software is increased. An open architecture controller is being sought that would allow flexibility and information exchange.

Keywords: drilling, milling, chucks, cutting edges, tools, machines

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4716 Knowledge Transfer from Experts to Novice: An Empirical Study on Online Communities

Authors: Firmansyah David

Abstract:

This paper aims to investigate factors that drive individuals to transfer their knowledge in the context of online communities. By revisiting tacit-to-explicit knowledge creation, this research attempts to contribute empirically using three online forums (1) Software Engineering; (2) Aerospace Simulator; (3) Health Insurance System. A qualitative approach was deployed to map and recognize the pattern of users ‘Knowledge Transfer (KT), particularly from expert to novice. The findings suggest a common form on how experts give their effort to formulate ‘explicit’ knowledge and how novices ‘understand’ such knowledge. This research underlines that skill; intuition, judgment; value and belief are the prominent factors, both for experts and novice. Further, this research has recognized the groups of expert and novice by their ability to transfer and to ‘adopt’ new knowledge. Future research infers to triangulate the method in which the quantitative study is needed to measure the level of adoption of (new) knowledge by individuals.

Keywords: explicit, expert, knowledge, online community

Procedia PDF Downloads 272