• Title/Summary/Keyword: Objective point of view

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A Study on the Optimization Strategy using Permanent Magnet Pole Shape Optimization of a Large Scale BLDC Motor (대용량 BLDC 전동기의 영구자석 형상 최적화를 통한 최적화 기법 연구)

  • Woo, Sung-Hyun;Shin, Pan-Seok;Oh, Jin-Seok;Kong, Yeong-Kyung;Bin, Jae-Goo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.897-903
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    • 2010
  • This paper presents a response surface method(RSM) with Latin Hypercube Sampling strategy, which is employed to optimize a magnet pole shape of large scale BLDC motor to minimize the cogging torque. The proposed LHS algorithm consists of the multi-objective Pareto optimization and (1+1) evolution strategy. The algorithm is compared with the uniform sampling point method in view points of computing time and convergence. In order to verify the developed algorithm, a 6 MW BLDC motor is simulated with 4 design parameters (arc length and 3 variables for magnet) and 4 constraints for minimizing of the cogging torque. The optimization procedure has two stages; the fist is to optimize the arc length of the PM and the second is to optimize the magnet pole shape by using the proposed hybrid algorithm. At the 3rd iteration, an optimal point is obtained, and the cogging torque of the optimized shape is converged to about 14% of the initial one. It means that 3 iterations aregood enough to obtain the optimal design parameters in the program.

Bibliographic Analysis of Aging Anxiety and Lifestyle (노화불안과 라이프스타일에 대한 계량서지학적 분석)

  • Park, Sun Ha;Park, Hae Yean;Lim, Young Myoung
    • Therapeutic Science for Rehabilitation
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    • v.11 no.2
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    • pp.25-37
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    • 2022
  • Objective : Through the bibliographic analysis method, the flow of research is grasped from a macroscopic point of view and the connection system of key words is conducted. The purpose of this is to provide basic data for conducting research on aging anxiety and lifestyle. Methods : Among the bibliographic analysis methods, a citation analysis method that identifies the association based on the number of citations and a simultaneous appearance word analysis method that identifies the association based on the number of keywords appeared was used. VOSviewer was used to cluster and chart the analyzed information. Results : The frequency of occurrence of papers by year showed a gradual increase until 2017 and a rapid increase from 2018. In the field of research paper study, research was most actively conducted in the field of psychiatry. In the citation analysis, the United States, Australia, and the United Kingdom showed high correlation with each other, and as a result of conducting simultaneous word analysis on major keywords, words with high association with aging anxiety were found to be depression. Conclusion : This study is meaningful in that it grasped the flow of aging anxiety and lifestyle research from a macroscopic point of view using a bibliographic analysis method. Based on this, it is expected to understand the importance of lifestyle from the preventive point of view of aging and to be used as basic data for intervention and related education.

Evaluation Method of Bonded Strength in Adhesively Bonded Structures of the Aluminum Alloys (알루미늄 합금의 접착구조물에 대한 접착강도의 평가방법)

  • 정남용
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.1
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    • pp.35-44
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    • 1999
  • In a view point of earth environmental protection and social requirement, adhesively bonded structures of aluminum alloys have become to be employed for the purpose of decreasing fuel ratio by weight reduction and to improve performance in various engineering fields such as aircrafts, automobiles, rolling stocks and so on. In spite of such wide applications in adhesively bonded structures of aluminum alloys, the quantitative fracture criterion and evolution method of its bonded strength have not been established yet. The objective of this paper is to establish fracture criterion considering stress singularity at interface edges in adhesively bonded structures of aluminum alloys. Through the analyses of boundary element method and static fracture experiments with three different types of specimens in the adhesively bonded joints of aluminum alloys, its fracture criterion was proposed and discussed about strength evolution of adhesively bonded structures.

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Ergonomic Evaluation of Some University Laboratories

  • Lee, Yun Keun;Lee, Ik Mo;Park, Jeongim;Yoon, Chung Sik;Rhie, Kwang Won;Park, Hee Sok
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.4
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    • pp.397-403
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    • 2013
  • Objective: This article aims to report the results of ergonomic evaluation of some university laboratories. Background: Laboratory researchers are at risk for musculoskeletal injuries during routine laboratory procedures. However, little attention has paid to the working conditions of laboratory researchers, especially in Korea. Method: A checklist and questionnaire was developed and used to analyze the work conditions of 27 laboratories of chemistry, biology and pharmacy. Results: It was found that glove box, clean bench, and computer workstation are better than microscopy, and fume hood tasks, from ergonomic point of view. Conclusion: No domestic guideline is available for ergonomic intervention of laboratories. Further attention and studies are anticipated to improve the working conditions of laboratories.

A Comparison of Ontology Tools Based on OWL (OWL 기반의 온톨로지 도구 비교분석)

  • Ihm, Hyoung-Shin;Hwang, Yun-Young;Eom, Dong-Myuong;Lee, Kyu-Chul
    • Korean Journal of Oriental Medicine
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    • v.12 no.1
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    • pp.1-12
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    • 2006
  • Recently according to the WIPO's policy of preserving traditional knowledge, constructing the database of traditional knowledge is in progress. To maximize the retrieving power of the knowledge resource systems which will be developed later, it is necessary to construct the ontology for the concepts used by traditional knowledge. In order to construct the ontology systematically, a standardized ontology representation method is needed, and OWL(Web Ontology Language) is the recommendation of W3C(World Wide Web Consortium) and is widely used. Ontology tools can be used to ease the construction of OWL ontology, but no research about the comparison of OWL ontology tools exists. This paper compares the tools of OWL by an objective point of view and with that one can make a decision of using the appropriate tool for constructing OWL ontologies.

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Towards a Development Strategy for the Recruitment and Retention of Women Seafarers in Cargo Ships with Particular Reference to the Republic of Korea

  • Jo, So-Hyun
    • Journal of Navigation and Port Research
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    • v.35 no.2
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    • pp.137-147
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    • 2011
  • The prime objective set for paper is to identify what are the women seafarers' problems and concerns regarding employment on cargo ships. From the cargo ship point of view, the question then is how to provide sufficient solutions for women seafarers in the male-dominated workplace of the ship through Corporate Social Responsibility(CSR) activities. The methodologies of study combine qualitative and quantitative research methods. The progress of research is to conduct a survey by asking a consistent set of key opinion leaders from the Republic of Korea. Moreover, to evaluate the elements of the result, the research explores the way in which we should consider giving priority to aspects of the problem. Finally, based on the terms of CSR, the author recommends measures to support the needs of women when they are employed onboard the world's merchant vessels.

Controversies on the Usefulness of Nerve Conduction Study in the Early Diagnosis of Diabetic Polyneuropathy (당뇨병성 다발신경병증의 조기 진단에서 신경전도검사의 유용성에 관한 논란)

  • Joo, In-Soo
    • Annals of Clinical Neurophysiology
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    • v.10 no.1
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    • pp.25-28
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    • 2008
  • Diabetic polyneuropathy (DPN) is the most frequently encountered form of neuropathy in diabetic patients, and it either relentlessly progresses or remains relatively stable for many years, not showing any trend towards improvement. From this point of view, early detection of DPN is very important to prevent the irreversible change of the peripheral nerve from diabetic insults. Although a number of clinical symptoms and/or deficit scales have been developed for clinical or research purposes, nerve conduction study (NCS) has been known one of the most objective and sensitive tools to detect peripheral nerve dysfunctions in diabetic patients. NCS, however, also have several shortcomings. The next two consecutive articles will focus on debates about diagnostic usefulness of NCS and on recent updates of other diagnostic tests including quantitative sensory testings and skin biopsy in the field of diabetic polyneuropathy.

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Comparison of Ministry of Labor Notification for VDT Work Management and KS A ISO 9241 (VDT 취급작업 관리를 위한 노동부고시와 KS A/ISO 9241의 비교연구)

  • Park, Hee-Sok;Lee, Yun-Keun;Ok, Dong-Min
    • Journal of the Ergonomics Society of Korea
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    • v.28 no.4
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    • pp.109-115
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    • 2009
  • The objective of this paper is to compare two national guidelines on the VDT work management published by Ministry of Labor(MOL) and Korean Standard(KS), and suggest possible modifications of them. The scope of this paper was limited to the desktop type of VDT jobs, excluding laptop environment. In addition, questionnaires were administered to office workers to collect information on the discomfort levels in meeting the MOL Notification. From ergonomic point of view, the most noticeable differences between two guidelines were found with respect to the heights of chairs and desks. In fact, the ranges specified in each guideline were not the same. In the field surveys, it could be known that work environments should be improved.

A REAL TIME CFD SIMULATION OF THE VERTICAL-AXIAL WIND TURBINE (전산해석을 이용한 수직축 풍력터빈의 실시간 공력해석)

  • Lee, M.S.;Han, B.Y.;Park, H.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.147-154
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    • 2010
  • The world is gradually running short of fossil fuel. Currently, the role of wind turbine is attracting great attention from all over the world. The objective of this study is to investigate blades of Vertical-axial wind turbine (VAWT) for optimum design using the CFD from the aerodynamics point of view. Because one of the performance of wind turbine depends on shape of blades, the study of comparing one gyro mill type blade and a modified one was carried out. Using the results of computation, we calculated and compared RPM for both models at same wind velocity. And we calculated angular acceleration and moment of inertia to find torque in every time-step. And the pressure contour and velocity profile around the blade were analyzed Also, this study is performed to calculate the wake effect.

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A Clinical Case Study on the Postpartum Depression (산후 우울증 환자 1례에 대한 증례보고)

  • Nam, Se-Hyeon;Lee, Hyun
    • Journal of Haehwa Medicine
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    • v.16 no.1
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    • pp.9-16
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    • 2007
  • Postpartum depression is a kind of serious problem which influences on the postpartum woman, her family and infant. It has been known to be caused by many factors and some depression scales have been used to assess the degree of postpartum depression. Edinburgh postnatal depression scale(EPDS) is simple and efficient method. Because of the difficulty of diagnosis and valuation on the postpartum depression, there has been a few case report on oriental medical treatment. I report one postpartum depression case which was valuated by EPDS and had objective evidence. In this case herbal treatment and acupuncture was efficacious on the postpartum depression. I think, though six month has passed from parturition, there need to be treated after parturition weakness and deficiency point of view.

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