• 제목/요약/키워드: 김석철

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무중력 유동층 건조기의 건조특성에 관한 연구 (Characteristics of Non-gravity Fluidized Dryer)

  • 김석철;배동규;한지웅;금성민;이창언
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.220-227
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    • 2000
  • The purpose of this study is to develop the non-gravity fluidized dryer. In this non-gravity fluidized dryer the fluidized zone is produced by two paddles in mixer, which maximizes the surface area of materials and then heated air through the guiding panels dehumidify them. This can conduct the drying process quickly and control moisture contents to lower limits. The ventilation system is closed loop system, which can be changeable to open system, and can be used as a multi-purposed dryer in which mixing, drying, granulating and cooling process is conducted. In order to develop non-gravity fluidized dryer, in the first the fundamental experiments performed to mixing accuracy and then the other parts of dryer and control system were examined to check whether they were designed properly and operated harmoniously with mixer. Also the preparatory experiments were fulfilled to examine the efficiency and reliability of dryer. Lastly, on the basis of preparatory experiments in case the initial moisture contents, desired moisture contents, heated air velocity and heating temperature were vary, performance test for the non-gravity fluidized dryer carried out.

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대도시 대기오염 추세 분석을 위한 새로운 박스모델의 유도 (Derivation of New Box Model to Analyze the Air Pollution Trends in a Metropolitan Area)

  • 김석철;조승헌
    • 한국대기환경학회지
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    • 제21권3호
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    • pp.377-397
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    • 2005
  • A new box model is proposed to describe the dynamic trend of the spatially averaged concentrations of pollutants over a large urban area such as metropolitan Seoul. Being averaged temporally and spatially over a thresh-hold scales, the dynamics of the pollutant concentration becomes simple enough that the governing equation can be expressed in an explicit algebraic form as a function of several meteorological factors and the pollutant emission rate. The single most important meteorological factor is the wind speed dominating the daily variations of the pollutant concentrations. Given the meteorological data from the surface station in the metropolitan Seoul, the model concentration shows excellent agreement with observations from January 1, 1990 to December 31, 2000: the modeling uncertainty, for example, of $NO_2$ concentrations, defined as mean differences between the model concentrations and observations is $16\%$ of the model concentrations. Even for $PM_{10}$ of which secondary sources are considered to be very important and simple box model is irrelevant to, the model performance turns out good, modeling uncertainty being about $32\%$.

응축형 가스보일러 열교환기의 열전달특성에 관한 수치적 연구 (The Numerical Study on the Heat Transfer Characteristics of Heat Exchanger for Condensing Gas Boiler)

  • 김석철;금성민;이창언
    • 대한기계학회논문집B
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    • 제25권12호
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    • pp.1853-1860
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    • 2001
  • Characteristics of fluid flow and heat transfer in a tube with disk and annular baffle for heat exchanger of condensing boiler was numerically studied. The STAR-CD code was used to solve the governing equations and the temperature and flow fields were investigated. The interval between tube and annular baffle, height and diameter of baffle were selected as important design parameters, and the effects of these parameters on heat transfer and fluid flow were studied. As a result, in the case of with interval, the pressure was decreased, but heat transfer was increased. Heat transfer was slowly increased as the size of disk and annular baffle were increased and the distance between baffles were decreased. The pressure drop was rapidly changed fur diameter and size of disk and annular baffle. In addition, it was desirable that optimal conditions to design heat exchanger were about B$\_$a/R=0.5, L/R=1.

TOPSIS방법을 이용한 물류서비스품질 우선순위 선정에 관한 연구 (A Study on the Selection of Logistic Service Quality Priority with TOPSIS)

  • 김석철;강경식
    • 대한안전경영과학회지
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    • 제19권3호
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    • pp.137-150
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    • 2017
  • Logistic enterprises want to be competitive enterprises in fierce logistic market and worry about the securement of discriminative competitiveness for it. The standards for the judgement of logistic industry's maintenance of competitiveness are not only economic feasibility of logistic costs but also the satisfaction of users because well-established service system for variety and enhancement of logistic needs. Some of the quality attributes sufficiently satisfy expectation of customers, but not guarantee high-quality satisfaction. Therefore, it's difficult to grasp quality attributes with the existing approach of perceived service quality. Quality attribute model suggested by Kano is widely used as the concept is accurate, there is high possibility to be used at the stage of product/service planning, and it can be easily applied. Kano model has a limitation that quality attributes are classified with mode and the differences between strong property of the quality attribute and week property in quality attributes were ignored. Therefore, Timko calculated customer satisfaction coefficient with the result of Kano's survey and effects of customer satisfaction and unsatisfaction through relations between satisfaction coefficient and unsatisfaction coefficient. The purposes of this study are to use ASC, the average of satisfaction coefficient and unsatisfaction, as the satisfaction of quality characteristics, decide the importance of quality characteristics with TOPSIS, a representative multi-standard decision-making method, and calculate strategy improvement propriety of logistic service quality.

건설중재 활성화를 위한 시스템 구축방안 연구 - 미국의 건설중재운영시스템을 중심으로 - (A Study on the Effective System of the Construction Arbitration)

  • 김석철
    • 한국중재학회지:중재연구
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    • 제14권1호
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    • pp.103-132
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    • 2004
  • This paper suggests the establishment of construction arbitration tribunal in The Korean Commercial Arbitration Board or the construction arbitration institution under the Ministry of Construction for effective system of Construction Arbitration. Our conclusion tells that it is desirable to establish construction arbitration institution under the Ministry of Construction upon the result of analyzing some factors such as participation of construction workers, sophistication of construction field. In contrast, it is more desirable to establish the construction arbitration tribunal in The Korean Commercial Arbitration Board when we consider the feasibility, sophistication of ADR, organization, rules, arbitrator availability, internationalization Therefore, our final suggestion is to establish construction arbitration tribunal in The Korean Commercial Arbitration Board for effective system of Construction Arbitration. More detailed are as follows: . Establishment of the committee for resolution of construction disputes consisting of experts and specialists from construction-related institution, union, law firm and universities. 1 The committee manages finance, rules on construction arbitration and arbitrator members. 1 Establishment of intermediation team, construction arbitration team, housing arbitration team, real estate arbitration team under the construction arbitration tribunal . Establishment of a committee of arrangements consisting of experts and specialists from The Korean Association of Arbitration Studies, Korea Arbitrators Association, The Korean Commercial Arbitration Board, The Construction Association of Korea in order to accomplish effective system for construction arbitration.

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표면파 분산특성과 전기비저항 분포특성에 대한 인접구조물의 영향 (Influence of Adjacent Structures on Surface-Wave Dispersion Characteristics and 2-D Resistivity Structure)

  • 조성호;김봉찬;조미라;김석철;윤대희;홍재호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1318-1327
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    • 2008
  • Geotechnical sites in urban areas may have embedded structures such as utility lines and underground concrete structures, which cause difficulties in site investigation. This study is a preliminary research to establish knowledge base for developing an optimal technique for site investigation in urban areas. Surface-wave method and resistivity survey, which are frequently adopted for non-destructive site-investigation for geotechnical sites, were investigated to characterize effects of adjacent structures. In case of surface wave method, patterns of wave propagation were investigated for typical sets of multi-layered geotechnical profiles by numerical simulation based on forward modeling theory and field experiments for small-size model tests and real-scale tests in the field. In case of resistivity survey, 3-D finite element analyses and field tests were performed to investigate effects of adjacent concrete structures. These theoretical and experimental researches for surface-wave method and resistivity survey resulted in establishing physical criteria to cause interference of adjacent structures in site investigation at urban areas.

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정주형 역사경관 보전에 대한 주민과 방문객의 인식 연구 - 산청 남사마을과 함양 개평마을을 대상으로 - (A Study on Perception of Conservation of Settlement Historical Landscape - Focused on the village in Sancheong and Hamyang -)

  • 정연승;강석진;고영훈;김석철
    • 한국농촌건축학회논문집
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    • 제18권4호
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    • pp.25-32
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    • 2016
  • Historical and cultural heritage provides a clue to reflect on the life of the era. Views of traditional village are the thing which can show us the life style and value of our ancestors and must be conserved as the values and traditional culture. Traditional village that has the historical value and descended to this day by adapting to environmental and social changes with the strong continuity is a part of the value of the residents' life and should be conserved with the physical environment, community and quality of the inhabitants' life. Therefore, this study is to analysis the difference of perception and the cause regarding conservation of the historical landscape and how the landscape influences on the residents and visitors. Based on those things, this study is to ultimately introspect importance of the residents' participation and meaning of the difference of perception about conservation of the historical landscape.

강성특성치를 이용한 고속전철 콘크리트궤도의 처짐가능성 평가 (Evaluation of Concrete-Track Deformation for High-Speed Railways by Characteristic Stiffness)

  • 조성호;이일화;황선근;강태호;김석철
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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    • pp.641-646
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    • 2009
  • Concrete tracks are superior to ballast tracks in the aspect of durability, maintenance and safety. However, deteriorated stiffness of railroad bed and settlement of soft ground induced by trapped or seepage water lead to problems in safety of train operation. In this research, characteristic stiffness of concrete tracks, which is determined from FRACTAL (Flexural-Rigidity Assessment of Concrete Tracks by Antisymmetric Lamb Waves) technique, was employed as an index of track displacement. The characteristic stiffness is defined using Poisson's ratio, moment of inertia and stiffness ratio of subgrade to slab. To verify validity and reliability of the proposed characteristic stiffness, experimental and theoretical researches were performed. Feasibility of the characteristic stiffness based on FRACTAL technique was proved at a real concrete track for Korean high-speed trains. Validity of the FRACTAL technique was also verified by comparing the results of impulse-response tests performed at the same measurement array and the results of SASW tests and DC resistivity survey performed at a shoulder nearby the track.

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소비자피해구제 실태분석을 통한 소비자중재제도 도입방안 연구 (A Study on Consumer Arbitration System by Empirical Analysis on Redemption for Consumer′s Claim)

  • 김석철
    • 한국중재학회지:중재연구
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    • 제12권1호
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    • pp.207-239
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    • 2002
  • The redemption system for consumer's claim is intended to deal with the conflicts between consumers and firms in their transaction of goods and service ensuring consumer's basic right. In general, the redemption system for consumer's claim requires promptness of redemption, free charge of claim procedure for consumers and constructive response of firms. However, the current redemption system in Korea has some limitations in its authority in the sense that it has only the right for mediation of consultation and agreement and thus the involved consumer should forfeit his/her claim or should go to legal suit which requires high cost and time when the mediation work is failed between two parties. As it is shown in result of survey on empirical cases produced by the Consumer Dispute Mediation Committee in Consumer Protection Board of Korea in 2001, the 20.3% of total claims have failed to reach final mediation, while the BBB case in the U. S. has recorded 19% of arbitration success after its failure in mediation. Therefore, it is strongly recommended for Korea to augment current. arbitration system toward assuring firm's cost liability, the principle of quick procedure through agreement on arbitration upon consumer's request. It is thus prerequisite for firms to be armed with the concrete entrepreneurship of responsibility on cost liability. In conclusion, we suggest restructuring of currently existing institution, rather than establishing new one through substantial augmenting the role of Consumer Dispute Mediation Committee In Consumer Protection Board of Korea and enlarging its business criteria of The Korean Commercial Arbitration Board by progressive development of the consumer protection program through amendment of current law for consumer protection.

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경남 김해지역의 대기환경개선 실천계획 수립 전후의 대기질 평가에 관한 연구 (Study on the Assessment of Air Quality Before and After Action Plan of Atmospheric Environment Improvement Establish at Gimhae, Gyeongnam Province)

  • 박종길;정우식;김석철;김은별
    • 한국환경과학회지
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    • 제17권10호
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    • pp.1111-1120
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    • 2008
  • In order to study the degree of improved air quality as an outcome of the action plan of Atmospheric Environment Improvement in Gimhae, Gyeongnam Province, we investigated the status and trends of air pollutant before and after the plan. Nitrogen dioxide and ozone, both classified as hazardous substances, were closely monitored with particular attention. The level of sulfur dioxide, nitrogen dioxide, fine particles and ozone (but for carbon monoxide) was decreased after the plan was implemented. The number of days on which ozone exceeded the National Ambient Air Quality Standard has decreased, but the level was still often exceeded. The level of nitrogen dioxide did not surpass until the 2006 standard, but when the revised 2007 standard was implemented, it exceeded 80% of some standards. The yearly level of ozone has decreased since the plan was introduced. The concentration of nitrogen dioxide, however, has reduced in high order area while increased in low order area.