• Title/Summary/Keyword: 직접탐색

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Automatic Design of Steel Frame Using Nonlinear Analysis (비선형 해석을 이용한 강뼈대구조물의 자동화설계)

  • Kim, Chang Sung;Ma, Sang Soo;Choi, Se Hyu;Kim, Seung Eock
    • Journal of Korean Society of Steel Construction
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    • v.14 no.2
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    • pp.339-348
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    • 2002
  • The study developed an automatic design method of steel frames which uses nonlinear analysis. The geometric nonlinearity was considered using stability functions. Likewise, the transverse shear deformation effect in a beam-column was explained. A direct search method was used as an automatic design technique. The unit value of each part was evaluated using LRFD interaction equation. The member with the largest unit value was replaced one by one with an adjacent larger member selected from the database. The weight of the steel frame was considered as an objective function. On the other hand, load-carrying capacities, deflections, inter-story drifts, and ductility requirement were used as constraint functions. Case studies of a two-dimensional and a three-dimensional two-story frames were presented.

Lead-Lag Controller Design of Direct Drive Servo Valve Using Complex Method (컴플렉스법에 의한 직접구동형서보밸브의 진상-지상 제어기 설계)

  • Lee, Seong-Rae
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1590-1595
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    • 2003
  • Direct drive servovalve(DDV) is a kind of one-stage valve since the rotary motion of DC motor is directly transferred to the linear motion of valve spool through the link. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the lead-lag controller is designed using the complex method that is one kind of constrained direct search method.

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Lead-Lag Controller Design of Direct Drive Servo Valve Using Complex Method (컴플렉스법에 의한 직접구동형서보밸브의 진상-지상 제어기 설계)

  • Lee, Seong-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1719-1726
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    • 2004
  • Direct drive servovalve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the DC motor. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the lead-lag controller is designed using the complex method that is one kind of constrained direct search method.

Study of the effect of career preparation and career maturity on employment among Specialized high school graduates (특성화고 고졸청년층의 진로준비 및 진로성숙이 취업에 미치는 영향 연구)

  • Lee, Man Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.8
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    • pp.4961-4971
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    • 2014
  • With regard to gaining employment for specialized high school graduates, what are the significant factors? Along with specialized high school's employment support, facility and subject support, vocational ability support, career guidance, and employment support are implemented at school. At the same time, individuals are learning career preparation behavior and job search behavior. Those factors influence the career maturity. Therefore, a question is, "Do they finally affect employment?" The independent variables were composed of satisfaction on school support, such as facility and subject support, career preparation behavior at home, pre-job search behavior, and career maturity. A structural equation was created and an analysis was conducted. As a result of the analysis, the satisfaction on school support has significant impacts on career maturity and career preparation behavior at home and influences on employment directly or indirectly. The career preparation behavior at home not only has a direct impact on employment, but also increases the pre- job search behavior and career maturity. In particular, it was confirmed that the career preparation behavior at home is the main factor to increase employment via the pre-job search behavior. Considering the effects among the factors in gender, the satisfaction on school support directly increases employment, particularly for women. Therefore, high-quality school support programs should be enhanced, focusing on employment support programs for women. In addition, as satisfaction on school support increases, women are more likely to undergo career preparation behavior at home. This suggests that the career preparation behavior for females, such as conversation about career, is a critical factor to increasing employment unlike males. Therefore, support programs for women that is aimed at parents should be developed.

A Learning Method of Stack and Queue through Solving Maze Exploration Problems with Robots (로봇의 미로 탐색 문제해결을 통한 스택과 큐 학습 방안)

  • Hong, Ki-Cheon
    • Journal of Digital Convergence
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    • v.10 no.11
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    • pp.613-618
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    • 2012
  • ICT education guidelines revised in 2005 reinforce computer science elements such as algorithm, data structure, and programming covering all schools. And Ministry of Education emphasizes STEAM education. Most important is that "How instruct them". This means necessity of contents. So this paper suggests learning method of Stack and Queue using LEGO MINDSTORMS NXT. The main purpose is that how stack and queue are used, when robot explore realistic maze. Teaching and learning strategies are algorithm, flowchart, and NXT-G programming. Simple maze has path in left or right, but complex maze has three-way intersection. These are developed by authors. Master robot explores maze and push stack, and then return to entrance using stack. Master robot explores maze and transmits path to slave's queue. And then slave robot drives without exploration. Students can naturally learn principles and applications of them. Through these studies, it can improves ability of logical and creative thinking. Furthermore it can apply to ICT and STEAM education.

Genetic Algorithms based on Maintaining a diversity of the population for Job-shop Scheduling Problem (다양성유지를 기반으로 한 Job-shop Scheduling Problem의 진화적 해법)

  • 권창근;오갑석
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.3
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    • pp.191-199
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    • 2001
  • This paper presents a new genetic algorithm for job-shop scheduling problems. When we design a genetic algorithm for difficult ordering problems such as job-shop scheduling problems, it is important to design encoding/crossover that is excellent in characteristic preservation and to maintain a diversity of population. We used Job-based order crossover(JOX). Since the schedules generated by JOX are not always active-schedule, we proposed a method to transform them into active schedulesby using the GT method with c)laracteristic preservation. We introduce strategies for maintaining a diversity of the population by eliminating same individuals in the population. Furthermore, we are not used mutation. Experiments have been done on two examples: Fisher s and Thompson s $lO\timeslO and 20\times5$ benchmark problem.

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Books Location Estimation System by Image Processing (영상처리를 이용한 도서 위치 추정 시스템)

  • Cho Dong-Uk
    • The KIPS Transactions:PartB
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    • v.12B no.1 s.97
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    • pp.17-24
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    • 2005
  • In this paper, we will show that a control search methodology is a alternative method of a sequential search which is difficult in finding books for arrangement at library or a bookstore when books are out of place. To solve the problem of the sequential search, we apply a edge operator and the Hough Transform to boundary of a taken photograph image book. We generate histogram by a projected image from boundary range of selected books and select title areas from this and possible areas which are a character number of title, authors, a publishing company and an array sequence. Finally, we can select the final possible area of a book location by a curve fitting and a regression line extraction, and show utility through experiment.

Binary Image Search using Hierarchical Bintree (계층적 이분트리를 활용한 이진 이미지 탐색 기법)

  • Kim, Sung Wan
    • Journal of Creative Information Culture
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    • v.6 no.1
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    • pp.41-48
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    • 2020
  • In order to represent and process spatial data, hierarchical data structures such as a quadtree or a bintree are used. Various approaches for linearly representing the bintree have been proposed. S-Tree has the advantage of compressing the storage space by expressing binary region image data as a linear binary bit stream, but the higher the resolution of the image, the longer the length of the binary bit stream, the longer the storage space and the lower the search performance. In this paper, we construct a hierarchical structure of multiple separated bintrees with a full binary tree structure and express each bintree as two linear binary bit streams to reduce the range required for image search. It improves the overall search performance by performing a simple number conversion instead of searching directly the binary bit string path. Through the performance evaluation by the worst-case space-time complexity analysis, it was analyzed that the proposed method has better search performance and space efficiency than the previous one.

Study on the Performance of Information Search Process in term of Attributes of Apps in Appstore and Buyer's Innovativeness (앱스토어 구매자의 혁신성과 앱의 속성에 따른 정보탐색 성과에 관한 연구)

  • Baek, Sung-Wook;Ahn, Hyo-Young;Lee, Zoon-Ky
    • Journal of Internet Computing and Services
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    • v.13 no.4
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    • pp.103-119
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    • 2012
  • In this paper, we conducted for information search process of users, who have experience to buy paid-application in Appstore, to find out difference of information searching efforts and information sources, reliance on the information in term of attributes of Apps and buyes' innovativenss. As a result, Innovative buyers take a effort to search various information source but they get help buying decision-making supports by own their efforts like searching in category. On the other hand, non-Innovative buyers who search informtion less than Innovative buyers, get information like recommendation from friend and Apps, then they keep those information help buying decision-making supports highly. Besides buyers of Utility Apps search on objective information sources mainly, but those sources have influence on buying decision-making supports. On the other side buyers of Enjoyment Apps consider reliance on the information more than information searching efforts to buying decision-making supports as they get information source like popularity. This research suggests operators of Appstore and app developers how to promote their Apps to users.

A Study on the Determinant Factors on Return in Internet Clothing Purchase (인터넷 쇼핑에서 의류제품 반품행동 결정요인)

  • Ji, Hye-Kyung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.12
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    • pp.1891-1902
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    • 2008
  • With concerns for consumers' return behaviors affecting internet shopping malls' profits and product management in the internet clothing market, this study is designed to investigate determinants affecting return and path models for return behaviors. For an empirical study, questionnaires are prepared and respondents in their 20s and 30s with internet clothing purchase experience are selected using the convenience sampling. A total of 517 questionnaires are used for the final analysis. Data are analyzed by using SPSS 12.0 software and descriptive statistics, $x^2$-test, discriminant analysis, regression analysis, and path analysis is conducted. The results are as follows. First, ones who have returned after purchasing clothing items in internet shopping reached 63.4% of the total consumers. Respondents returned items with price at 50 thousand won or less stood at 67.2%, and the most frequent return shopping malls are open markets with their return rate at 51.1%. Second, variables such as risk perception, information search, impulse buying, buying experience, and age have a positive effect on return experience. Impulse buying and buying experience turn out to have a significant effect on the degree of return, but risk perception, information search, age, and gender to have an insignificant effect. Return intention is significantly affected by risk perception, gender, and age. Third, the analysis of path model for return experience shows that perceived risk has a positively effect, and information search has a direct effect as well as an indirect effect through buying experience or impulse buying. The analysis of path model for the degree of return shows that risk perception does not have effect, but information search has indirect effect through buying experience or impulse buying. This study is thought to find consumers' return behavior characteristics in online shopping, and help businesses operating online shopping malls to efficiently manage returns and set up strategies against returns.