• Title/Summary/Keyword: multi variable control

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A Study on the Effective Routing Algorithm for Mobile Ad-hoc Wireless Program Develop Network (Ad-hoc 통신망에서 요구되는 라우팅 알고리즘 프로그램 개발연구)

  • Lee, Dong chul;Kim, Sung gwun;Cho, Se hyun;Lee, Hye soo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.623-625
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    • 2012
  • The nodes of Ad-hoc network are made up of location registration for sending informations and a great number of packet transmissions to maintain routing route among the nodes. Under this environment, a huge number of traffics would be generated as mobility variable occurs more than in physical network. Hence, in this paper, focused on to study the relationship of nodes to analyze the extent of the traffic in order to control the traffics of the multi-hop in Ad-hoc.

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A Software Architecture for High-speed PCE (Path Computation Element) Protocol (고성능 PCE (Path Computation Element) 프로토콜 소프트웨어 구조)

  • Lee, Wonhyuk;Kim, Seunhae;Kim, Hyuncheol
    • Convergence Security Journal
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    • v.13 no.6
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    • pp.3-9
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    • 2013
  • With the rapidly changing information communication environment and development of technologies, the informati on networks are evolved from traditional fixed form to an active variable network that flexible large variety of data can be transferred. To reflect the needs of users, the next generation using DWDM (Dense Wavelength Division M ultiplexing) transmission system and OXC (Optical Cross Connect) form a dynamic network. After that GMPLS (Ge neralized Multi-Protocol Label Switching) can be introduced to dynamically manage and control the Reconfigurable Optical Add-drop Multiplexer (ROADM)/Photonic Cross Connect (PXC) based network. This paper propose a softw are architecture of Path Computation Element (PCE) protocol that has proposed by Internet Engineering Task Force (IETF) to path computation. The functional blocks and Application Programming Interface (API) of the PCE protoco l implementation are also presented.

Performance Optimization of High Specific Speed Pump-Turbines by Means of Numerical Flow Simulation (CFD) and Model Testing

  • Kerschberger, Peter;Gehrer, Arno
    • International Journal of Fluid Machinery and Systems
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    • v.3 no.4
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    • pp.352-359
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    • 2010
  • In recent years, the market has shown increasing interest in pump-turbines. The prompt availability of pumped storage plants and the benefits to the power system achieved by peak lopping, providing reserve capacity, and rapid response in frequency control are providing a growing advantage. In this context, there is a need to develop pumpturbines that can reliably withstand dynamic operation modes, fast changes of discharge rate by adjusting the variable diffuser vanes, as well as fast changes from pumping to turbine operation. In the first part of the present study, various flow patterns linked to operation of a pump-turbine system are discussed. In this context, pump and turbine modes are presented separately and different load cases are shown in each operating mode. In order to create modern, competitive pump-turbine designs, this study further explains what design challenges should be considered in defining the geometry of a pump-turbine impeller. The second part of the paper describes an innovative, staggered approach to impeller development, applied to a low head pump-turbine project. The first level of the process consists of optimization strategies based on evolutionary algorithms together with 3D in-viscid flow analysis. In the next stage, the hydraulic behavior of both pump mode and turbine mode is evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Finally, the progress in hydraulic design is demonstrated by model test results that show a significant improvement in hydraulic performance compared to an existing reference design.

Applications of New Differential Dynamic Programming to the Control of Real-time Reservoir (새로운 미분동적 계획법에 의한 저수지군의 최적제어)

  • Sonu, Jung Ho;Lee, Jae Hyoung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.3
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    • pp.27-42
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    • 1984
  • The complexity and expensiveness of water resources projects have made optimum operation and design by computer-based techniques of increasing interest in recent years. Water resources problems in real world need many decisions under numerous constraints. In addition there are nonlinearities in the state and return function. This mathematical and technical troublesome must be overcome so that the optimum operation polices are determined. Then traditional dynamic optimization method encountered two major-cruxes: variable discretization and appearance of constraints. Even several recent methods which based on the Differential Dynamic Programming(DDP) have some difficulties in handling of constraints. This paper has presented New DDP which is applicable to multi-reservoir control. It is intended that the method suggested here is superior to abailable alternatives. This belief is supported by analysis and experiments(New DDT does not suffer course of dimensionality and requires no discretization and is able to handle easily all constraints nonlinearity).

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A New Interference-Aware Dynamic Safety Interval Protocol for Vehicular Networks

  • Yoo, Hongseok;Chang, Chu Seock;Kim, Dongkyun
    • Journal of Korea Society of Industrial Information Systems
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    • v.19 no.2
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    • pp.1-13
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    • 2014
  • In IEEE 802.11p/1609-based vehicular networks, vehicles are allowed to exchange safety and control messages only within time periods, called control channel (CCH) interval, which are scheduled periodically. Currently, the length of the CCH interval is set to the fixed value (i.e. 50ms). However, the fixed-length intervals cannot be effective for dynamically changing traffic load. Hence, some protocols have been recently proposed to support variable-length CCH intervals in order to improve channel utilization. In existing protocols, the CCH interval is subdivided into safety and non-safety intervals, and the length of each interval is dynamically adjusted to accommodate the estimated traffic load. However, they do not consider the presence of hidden nodes. Consequently, messages transmitted in each interval are likely to overlap with simultaneous transmissions (i.e. interference) from hidden nodes. Particularly, life-critical safety messages which are exchanged within the safety interval can be unreliably delivered due to such interference, which deteriorates QoS of safety applications such as cooperative collision warning. In this paper, we therefore propose a new interference-aware Dynamic Safety Interval (DSI) protocol. DSI calculates the number of vehicles sharing the channel with the consideration of hidden nodes. The safety interval is derived based on the measured number of vehicles. From simulation study using the ns-2, we verified that DSI outperforms the existing protocols in terms of various metrics such as broadcast delivery ration, collision probability and safety message delay.

Design of a Transformable Spherical Robot Based on Multi-Linkage Structure (복합 링크 구조 기반의 가변형 구형로봇 설계)

  • Kang, Hyeongseok;Joe, Seonggun;Lee, Dongkyu;Kim, Byungkyu
    • Journal of Aerospace System Engineering
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    • v.11 no.6
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    • pp.26-33
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    • 2017
  • We propose a variable frame structure connected with telescopic mast-shaped shaft for a robot displaying outstanding ability to cross obstacles, and for effective traction control. The wireless control system was built to extend and contract a deployable mechanism, which is shaped into a hoberman sphere assembled with frame structures. In order to develop important parameters for efficient locomotion, we derived an Euler-Lagrange equation for the spherical robot. According to the equation, the DC motor was selected. A prototype mechanism was tested and a Finite-Element Analysis (FEA) was conducted in parallel. Using these data, we constructed a deployable spherical robot with structural stability. The deployable robot moved at a speed of 0.85 m/s from 520 mm to 650 mm.

Influence on in-dorm university students' body-shape perception, obesity, and weight control toward Obesity stress (기숙사 남녀 대학생의 주관적 체형인식, 비만도, 체중조절 행태가 비만스트레스에 미치는 영향)

  • Lee, Hyun-Ju
    • Journal of Digital Convergence
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    • v.11 no.11
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    • pp.573-583
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    • 2013
  • Targeting in-dorm university students, this study is to check body-shape perception, obesity, weight control, and obesity stress, and to figure out the effect level of each variables toward obesity stress. Data were collected by self-evaluation questionnaire from 305 respondents in dorms of a university, and the survey was conducted from May 27 to June 7 of the year 2013. As a result of the survey, both male and female students did not properly perceive their own body-shape. Female students felt that they were fat more than male students did; on the other hand, male students felt that they were skinny even though they were in standard. Females felt more obesity stress than males, and for both male and female students, more obesity resulted in deeper obesity stress. For female students, when the actual body shape is not similar to the body shape that they believe to be, they feel more obesity stress; however for male students, the result was reversed. The group that tried weight control felt more obesity stress than the other group, for both males and females. In addition, for both male and female, the group that has more will toward weight control felt more obesity stress. The effect factors that were checked through multi-variable analysis is like the following: for male students, as they feel fat and as they pay more attention to weight control, the obesity stress increased, and for female students, as they pay more attention to weight control, the obesity stress increased. Focusing on higher obesity stress groups that are distinguished through applying factors to influence on decreasing obesity stress based on the analysis result, and especially for male university students, running exercise programs at the same time for skinny bodies to gain fat would be more effective to decrease obesity stress.

An Longitudinal Analysis of Changing Beliefs on the Use in IT Educatee by Elaboration Likelihood Model (정교화 가능성 모형에 의한 IT 피교육자 신용 믿음 변화의 종단분석)

  • Lee, Woong-Kyu
    • Asia pacific journal of information systems
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    • v.18 no.3
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    • pp.147-165
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    • 2008
  • IT education can be summarized as persuading the educatee to accept IT. The persuasion is made by delivering the messages for how-to-use and where-to-use to the educatee, which leads formulation of a belief structure for using IT. Therefore, message based persuasion theory, as well as IT acceptance theories such as technology acceptance model(TAM), would play a very important role for explaining IT education. According to elaboration likelihood model(ELM) that has been considered as one of the most influential persuasion theories, people change attitude or perception by two routes, central route and peripheral route. In central route, people would think critically about issue-related arguments in an informational message. In peripheral route, subjects rely on cues regarding the target behavior with less cognitive efforts. Moreover, such persuasion process is not a one-shot program but continuous repetition with feedbacks, which leads to changing a belief structure for using IT. An educatee would get more knowledge and experiences of using IT as following an education program, and be more dependent on a central route than a peripheral route. Such change would reformulate a belief structure which is different from the intial one. The objectives of this study are the following two: First, an identification of the relationship between ELM and belief structures for using IT. Especially, we analyze the effects of message interpretation through both of central and peripheral routes on perceived usefulness which is an important explaining variable in TAM and perceived use control which have perceived ease of use and perceived controllability as sub-dimensions. Second, a longitudinal analysis of the above effects. In other words, change of the relationship between interpretation of message delivered by IT education and beliefs of IT using is analyzed longitudinally. For achievement of our objectives, we suggest a research model, which is constructed as three-layered. While first layer has a dependent variable, use intention, second one has perceived usefulness and perceived use control that has two sub-concepts, perceived ease of use and perceived controllability. Finally, third one is related with two routes in ELM, source credibility and argument quality which are operationalization of peripheral route and central route respectively. By these variables, we suggest five hypotheses. In addition to relationship among variables, we suggest two additional hypotheses, moderation effects of time in the relationships between perceived usefulness and two routes. That is, source credibility's influence on perceived usefulness is decreased as time flows, and argument quality's influence is increased. For validation of it, our research model is tested empirically. With measurements which have been validated in the other studies, we survey students in an Excel class two times for longitudinal analysis. Data Analysis is done by partial least square(PLS), which is known as an appropriate approach for multi-group comparison analysis with a small sized sample as like this study. In result. all hypotheses are statistically supported. One of theoretical contributions in this study is an analysis of IT education based on ELM and TAM which are considered as important theories in psychology and IS theories respectively. A longitudinal analysis by comparison between two surveys based on PLS is also considered as a methodological contribution. In practice, finding the importance of peripheral route in early stage of IT education should be notable.

The Relationship between the Migration of the Young Generation and Housing Policy: Focused on the Seoul Metropolitan Area (청년층의 인구이동과 주택정책의 관련성에 관한 연구: 수도권을 중심으로)

  • Park, Bu Myung;Kim, Seong-A
    • Land and Housing Review
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    • v.11 no.1
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    • pp.21-38
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    • 2020
  • This study examined the population movement of the young generation in accordance with the characteristics of housing market focusing on the housing problem of youth issues. Targeting 64 local governments in the seoul metropolitan area, the temporal range was decided as 2015. Setting up the rising population in 19-34 as a dependent variable, supposing that each age group shows different characteristics, it was divided into age groups in 19~34, 19~29, and 25~34. The population movement of the young generation in accordance with the characteristics of housing market was considered through the multiple regression analysis. In the results, the population movement of the young generation was influenced by the change in detached multi-family housing and the rate of housing supply. The increase of detached multi-family housing promoted the population inflow of the young generation while the population movement of the young generation was disturbed by the rising rate of housing supply. Also, when the local characteristics are not controlled, the young generation hesitates to enter the region where relatively high rent should be paid while the new housing supply focusing on apartment is hard to be selected by the young generation for residence because of the size and price. The population movement of the young generation looked quite different in each age group. The population inflow of the young generation in 19~29 was influenced when there were many officetels and non-apartments on top of detached multi-family housing. On the contrary, the population movement of the young generation in 25~34 was significantly influenced by the increase of the whole size of completed apartment area. Even though it was not the research subject of this study, among control variables, the financial independence and daily average number of get-on/off had effects on the movement of the young generation. It means that the housing type preferred by college students and social novices is different from the housing type preferred by the group with experiences in marriage and childbirth within the same young generation. Thus, it would be necessary to divide the purposes of policies for each subject when executing the youth housing policies.

The Effect of Social Network on Information Sharing in Franchise System (프랜차이즈시스템의 사회연결망 특성이 정보공유에 미치는 영향)

  • Yun, Han-Sung;Bae, Sang-Wook;Noh, Jung-Koo
    • Journal of Distribution Research
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    • v.16 no.2
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    • pp.95-118
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    • 2011
  • The purpose of this study is as follows. First, we investigate empirically the effects of social network properties such as social network density and centrality of a franchisee on its information sharing with various subjects such as the franchisor and other franchisees in the franchise system. Second, we examine exploratively if tie strength between a franchisee and its franchisor plays a moderating role on the relationship between social network properties and information sharing. The study model was established as shown in

    . We gathered 200 data from franchisees in Busan through a questionnaire survey and used 189 data for our purpose. To improve the quality of data, we selected respondents from the franchisees' owners or managers that had contacted often with their franchisor and other franchisees in the franchise system. Our data analysis began with reliability analysis, exploratory and confirmatory factor analysis, on the multi-item measures of social network density, social network centrality, tie strength, information sharing and control variables such as shared goals and ownership to assess the reliability and validity of those measures. The results were shown that the presented values satisfied the general criteria for reliability and validity. We tested our hypotheses using a hierarchical multiple regression analysis in four steps. Model 1 regressed the dependent variable(information sharing) only on control variables(shared goals, ownership). Model 2 added main effect variables(social network density, social network centrality) in Model 1. Model 3 added a moderating variable(tie strength) in Model 2. Finally, Model 4 added interaction terms between the main variables and the moderating variable in Model 3. We used a mean-centering method for the main variables and the moderating variable to minimize the multicollinearity problem due to the interaction terms in Model 4. Two important empirical findings emerge from this study. In other words, the effects of social network properties and tie strength on a franchisee's information sharing depend on subject types such as the franchisor and other franchisees in franchise system. First, social network centrality, tie strength, the interaction between social network density and tie strength and the interaction between social network centrality and tie strength all affect significantly a franchisee's information sharing with its franchisor. By the way, the interaction between social network centrality and tie strength has a negative effect on its information sharing while the interaction of social network density and tie strength has a positive effect on its information sharing. Second, both social network centrality affects significantly and directly a franchisee's information sharing with other franchisees in the franchise system. However, there does not exist the moderating role of tie strength in the second case. Finally, we suggest the implications of our findings and some avenues for future research.

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