• 제목/요약/키워드: Open Problem

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A study on distribution system reconfiguration with constant power load using Genetic algorithms (유전알고리즘을 이용한 정전력부하를 갖는 배전계통 선로의 재구성에 관한 연구)

  • Mun, K.J.;Kim, H.S.;Hwang, G.H.;Lee, H.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.71-73
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    • 1995
  • This paper presents an optimization technique using genetic algorithms(GA) for loss minimization in the distribution network reconfiguration. Determining switch position to be opened for loss minimization in the radial distribution system is a discrete optimization problem. GA is appropriate to solve the multivariable optimization problem and it uses population, not a solution. For this reason, GA is attractive to solve this problem. In this paper, we aimed at finding appropriate open sectionalizing switch position using GA, which can lead to minimum transmission losses.

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Optimum Design on Reduction of Torque Ripple for a Synchronous Reluctance Motor with Concentrated Winding using Response Surface Methodology (반응표면법을 이용한 집중권선 동기 릴럭턴스 전동기의 토크 리플 저감에 관한 최적설계)

  • Park Seong-June;Lee Jung-Ho
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.2
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    • pp.69-75
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    • 2006
  • This paper deals with the optimum design solution on reduction of torque ripple for a Synchronous Reluctance Motor with concentrated winding using response surface methodology. The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate the nonlinear solution. Comparisons are given with characteristics of a SynRM according to the stator winding, slot number, open width of slot, slot depth, teeth width variation in concentrated winding SynRM, respectively. This paper presents an optimization procedure using Response Surface Methodology (RSM) to determine design parameters for reducing torque ripple. RSM has been achieved to use the experimental design method in combination with finite Element Method (FEM) and well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. Moreover, Sequential Quadratic Problem (SQP) method is used to solve the resulting of constrained nonlinear optimization problem.

Design and Implementation of User-oriented Face Detection System for Application Developers (응용개발자를 위한 사용자 중심 얼굴검출 시스템 설계 및 구현)

  • Jang, Dae Sik
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.4
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    • pp.161-170
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    • 2010
  • This paper provides a novel approach for a user oriented system for face detection system for application developers. Even though there are many open source or commercial libraries to solve the problem of face detection, they are still hard to use because they require specific knowledge on detail algorithmic techniques. The purpose of this paper is to come up with a high-level system for face detection with which users can develop systems easily and even without specific knowledge on face detection theories and algorithms. Important conditions are firstly considered to categorize the large problem space of face detection. The conditions identified here are then represented as expressions so that application developers can use them to express various problems. Once the conditions are expressed by developers, the interpreter proposed take the role to interpret the conditions, find and organize the optimal algorithms to solve the represented problem with corresponding conditions. A proof-of-concept is implemented and some example problems are tested and analyzed to show the ease of use and usability.

QoS Provisioning in Wireless Body Area Networks: A Review on MAC Aspects

  • Thapa, Anup;Shin, Seok-Joo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.5
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    • pp.1267-1285
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    • 2012
  • Wireless Body Area Networks (WBANs) deal with variety of healthcare services with diverse Quality of Service (QoS) requirements. However, QoS handling is a challenging problem in such networks. In general, QoS related problems can be addressed from different layers in the networking protocol suite. Design of an efficient QoS aware Medium Access Control (MAC) protocol can address this problem in MAC layer. This paper analyzes the QoS requirements of WBAN, identifies the requisites of QoS handling system, and outlines the trends that are being followed for its advancement with focus on QoS issues at MAC layer. We review some prior works, compare them, and analyze the current research concerned with problem of providing QoS in WBAN. We also explore some open issues and discuss them.

Assessment of Mathematical Creativity in Mathematical Modeling

  • Jang, Hong-Shick
    • Research in Mathematical Education
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    • v.15 no.2
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    • pp.181-196
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    • 2011
  • In mathematical modeling tasks, where students are exposed to model-eliciting for real and open problems, students are supposed to formulate and use a variety of mathematical skills and tools at hand to achieve feasible and meaningful solutions using appropriate problem solving strategies. In contrast to problem solving activities in conventional math classes, math modeling tasks call for varieties of mathematical ability including mathematical creativity. Mathematical creativity encompasses complex and compound traits. Many researchers suggest the exhaustive list of criterions of mathematical creativity. With regard to the research considering the possibility of enhancing creativity via math modeling instruction, a quantitative scheme to scale and calibrate the creativity was investigated and the assessment of math modeling activity was suggested for practical purposes.

A Study on distribution system reconfiguration using Genetic algorithms (유전 알고리즘을 이용한 배전계통 선로 재구성에 관한 연구)

  • Mun, K.J.;Kim, H.S.;Hwang, G.H.;Lee, H.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.488-490
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    • 1995
  • This paper presents an optimization technique using genetic algorithms(GA) for loss minimization in the distribution network reconfiguration. Determining switch position to be opened for loss minimization in the radial distribution system is a discrete optimization problem. GA is appropriate to solve the multivariable optimization problem and it uses population, not a solution. For this reason, GA is attractive to solve this problem. In this paper, we aimed at finding appropriate open sectionalizing switch position using GA, which can lead to minimum transmission losses.

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The cluster-indexing collaborative filtering recommendation

  • Park, Tae-Hyup;Ingoo Han
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2003.05a
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    • pp.400-409
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    • 2003
  • Collaborative filtering (CF) recommendation is a knowledge sharing technology for distribution of opinions and facilitating contacts in network society between people with similar interests. The main concerns of the CF algorithm are about prediction accuracy, speed of response time, problem of data sparsity, and scalability. In general, the efforts of improving prediction algorithms and lessening response time are decoupled. We propose a three-step CF recommendation model which is composed of profiling, inferring, and predicting steps while considering prediction accuracy and computing speed simultaneously. This model combines a CF algorithm with two machine learning processes, SOM (Self-Organizing Map) and CBR (Case Based Reasoning) by changing an unsupervised clustering problem into a supervised user preference reasoning problem, which is a novel approach for the CF recommendation field. This paper demonstrates the utility of the CF recommendation based on SOM cluster-indexing CBR with validation against control algorithms through an open dataset of user preference.

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A Study on the Simulation Game Design for the Problem Solving of Regional Environment Problems (지역 환경 문제 해결을 위한 시뮬레이션 게임)

  • 유혜연;이동엽;최석진
    • Hwankyungkyoyuk
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    • v.15 no.1
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    • pp.125-136
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    • 2002
  • The ultimate goal of environmental education is to train the civilian who positively participates in solving environmental problems. To do above, not only accurate knowledge but also right value about environmental problems are needed. It is reasonable decision making that choose the first of all alternatives to solve the problems by accurate knowledge and right value of an individual. Teaching reasonable decision making in environmental education is related to raise the participant civilian toward regional environmental problem solving Simulation game helps that students have a opportunity to practice decision making skills about regional problems and give self-confidence to their decision making ability. So, the aim of this study is to present simulation games which is fit to elementary environmental education. The first one is for group decision making, the second one is for individual decision making. These can make a conclusion, winner and loser of games. But last one is open-ended game and aims to make explicit a variety of opinions, issues and conflicts to problem.

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A Survey of Public-Key Cryptography over Non-Abelian Groups

  • Lanel, G.H.J.;Jinasena, T.M.K.K.;Welihinda, B.A.K.
    • International Journal of Computer Science & Network Security
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    • v.21 no.4
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    • pp.289-300
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    • 2021
  • Non-abelian group based Cryptography is a field which has become a latest trend in research due to increasing vulnerabilities associated with the abelian group based cryptosystems which are in use at present and the interesting algebraic properties associated that can be thought to provide higher security. When developing cryptographic primitives based on non-abelian groups, the researchers have tried to extend the similar layouts associated with the traditional underlying mathematical problems and assumptions by almost mimicking their operations which is fascinating even to observe. This survey contributes in highlighting the different analogous extensions of traditional assumptions presented by various authors and a set of open problems. Further, suggestions to apply the Hamiltonian Cycle/Path Problem in a similar direction is presented.

Effects of Practical Problem-Based Home Economics Instruction Perceived by Both Female and Male High School Students. (남녀 고등학생이 인식안 실천적 문제 중심 가정과 수업의 효과)

  • 윤복순
    • Journal of the Korean Home Economics Association
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    • v.36 no.5
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    • pp.151-166
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    • 1998
  • The purpose of the study was to determine the effect of a practical problem-based instruction(PPBHEI) perceived by female and male high school students. One Group post-test only design was used in this quasiexperimental study. The experimental group of the study was 101(67 male and 34 female) second grade students of a high school in Kyung Kee Area. The Practical Problem-Based Home Economics Instruction had been conducted to the group during the 14th weeks of 1997 spring semester. Post-test including the two parts was conducted at the end of the semester. The instrument of the study was developed and used, based on the previous literature after testing validity and reliability by the researcher. The questionnaire was composed of open-ended question. The data of this study were analyzed by content analysis. The results were as follows: 1)both female and male respondents indicated PPBHEI helped to improve their friendships(93.1%), expression skills(69.3%), their thinking ability(82.1%), and problem soiving skills(76.2%); 2)both female and male respondents indicated that problems of PPBHEI were that a few students didn't like joining the class and classroom space was too small; and 3)half of students(52.3%) perceived the Practical Problem-Based Home Economics Instruction related to student achievement.

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