• 제목/요약/키워드: limit theory

검색결과 588건 처리시간 0.033초

균일 분포 횡하중 및 축하중을 받는 격자형 구조물의 최적 소성설계법 (Optimum Plastic Design Method of Grillages under Uniformly Distributed Lateral Loads and Axial Forces)

  • 정태준;김기성;박영호
    • 대한조선학회논문집
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    • 제33권2호
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    • pp.56-64
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    • 1996
  • 균일 분포 횡하중이 작용하는 격자형 구조물의 극한 해석법의 개발에 대한 이전의 연구(참고문헌 1과 5)를 검증해 보았고, 붕괴 이론에 있어서 면내력의 영향을 고찰 하였다. 논문의 주된 내용은 최소 중량과 최소 비용을 갖는 격자형 구조물의 최적설계법을 개발하였고, Pareto 해석법을 적용하여 다목적 함수를 갖는 구조물에서 최적 절충해를 구하는 최적화 기법을 소개하였다.

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실물 옵션 이론을 활용한 효과적인 R&D 투자 전략 (Effective R&D investment strategy using real options)

  • 최재경
    • 기술경영경제학회:학술대회논문집
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    • 기술경영경제학회 2001년도 제19회 하계학술발표회 논문집
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    • pp.117-130
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    • 2001
  • R&D is the core competence of an enterprise. Furthermore, R&D requires huge capital investment and has very risky characteristics. Therefore, to be successful in R&D process, several approaches of engineering economics are used prior to decision-making. Until now, typical approaches of engineering economics such as NPV(net present value) or DCF(Discounted cash flow) have been used. But, they cannot properly capture managerial flexibility to adapt and revise later decisions in response to unexpected market development. In a constantly changing and always uncertain marketplace, managerial operation flexibility and strategic adaptability have become vital in order to successfully capitalize on favorable future investment opportunities and limit losses from adverse market development. For the alternatives of conventional static decision-making approaches, new concept of using real options is introduced. Real option theory is based on financial option's characteristics and checks every revision interval whether situation have changed favorable to decision maker or not. In advantageous situation, the decision maker has only to go on. In contrast, with unfavorable situation, he abandons the investment immediately. In this aspect, real option model is more suitable in very uncertain and dynamic business environment in that it can provide the opportunity to cope with flexibility. This paper suggests efficient and effective R&D investment strategy by using real options model. In addition, this paper compares financial options and real options.

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청장년층 뇌졸중환자의 회복 경험 (The Recovery Experience of Young Adults and Middle Aged Stroke Patients)

  • 하주영;박형숙;이상주;전정해;조호윤;지영주
    • 성인간호학회지
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    • 제22권3호
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    • pp.342-351
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    • 2010
  • Purpose: The purpose of this study was to determine an increase in the number of younger and middle-aged people who have a stroke and the differences in their recovery experience compared with older people. Methods: The research question for this study was "What is the recovery experience of young adults and middle-aged people who suffer a stroke?". In order to answer the question, the grounded theory method was utilized. The data was collected through individual in-depth interviews of six participants, their age ranged from 36 to 45 years old. Results: After comparative analysis, the core category was "standing up for oneself with limit". The experience process were categorized into four stages: 'Facing Reality stage', 'Motivation stage', 'Desire Recovery stage', 'Self-Overcoming stage'. Conclusion: Most of the research for the recovery process was prognostic in nature and the results. This study was demonstrated certain indicators which can be useful in further research.

서양요리 품질의 결정요인에 관한 연구 (Chief Factors in the Quality of Western Food)

  • 정진우
    • 한국조리학회지
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    • 제7권3호
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    • pp.275-294
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    • 2001
  • There have been many discussions on the importance and part of quality in the marketing field. It also has been an effort in the cooking field to understand how the quality, recognized by customers, influences customer satisfaction in the process of serving western food. This study is a theory about evaluation methods of western food. It can be summarized in three views as below especially with sensuous evaluation methods. First, it is decoration. Visual factors, such as a receptacle and the amount of food in it, the arrangement of food colors, gloss of food, steam arising of from food, additional garnishes on food should be harmonious. Second, it is a flavor. The factors like the taste and smell of food, and feeling of food in the mouth can be evaluated with the taste and the smell. Third, it is texture. It is considered with the sense of touch, the motor sensation in the mouth and the hearing sense. Especially the sense of touch involves feel of receptacle when it is hot or cold as well as feel of food. This study has been conducted for providing customers with higher-quality western food, which is based on a theoretical study about evaluation methods. During the study, the limit was found that there is no measuring instrument, since the study was restricted in a theoretical work. For more accurate research, the measuring instrument should be developed through the positive research.

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베이지안 기법을 이용한 중성화에 노출된 콘크리트 구조물의 내구성 예측 (Durability Prediction for Concrete Structures Exposed to Carbonation Using a Bayesian Approach)

  • 정현준;김규선;주민관;이상철
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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    • pp.275-276
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    • 2009
  • 본 논문에서는 중성화에 노출된 콘크리트 구조불의 내구성을 예측하기 위한 새로운 접근 방법을 제시한다. 이 예측 방법은, 새로운 계측 데이터 있을 때 베이스 이론에 근거하여 지속적으로 업데이팅 을 할 수 있다. 모델 매개변수의 확률론적인 특성이 고려된다. 염해 해석 모델의 절차는 라틴 하이퍼 큐브 샘플 추출법으로 간단하게 정리되고 이를 통해 얻는 표본으로 결정된다. 이러한 새로운 방법은 중요한 콘크리트 구조물을 설계하기에 아주 유용하고 모니터링을 통한 실 콘크리트 구조물의 잔존수명을 예측 할 수 있다.

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슬라이딩 윈도우 방식의 터보 복호화기의 구조 및 성능 (The Structure and Performance of Turbo decoder using Sliding-window method)

  • 심병효;구창설;이봉운
    • 한국군사과학기술학회지
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    • 제3권1호
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    • pp.116-126
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    • 2000
  • Turbo codes are the most exciting and potentially important development in coding theory in recent years. They were introduced in 1993 by Berrou, Glavieux and $Thitimajshima,({(1)}$ and claimed to achieve near Shannon-limit error correction performance with relatively simple component codes and large interleavers. A required Eb/N0 of 0.7㏈ was reported for BER of $10^{-5}$ and code rate of $l/2.^{(1)}$ However, to implement the turbo code system, there are various important details that are necessary to reproduce these results such as AGC gain control, optimal wordlength determination, and metric rescaling. Further, the memory required to implement MAP-based turbo decoder is relatively considerable. In this paper, we confirmed the accuracy of these claims by computer simulation considering these points, and presented a optimal wordlength for Turbo code design. First, based on the analysis and simulation of the turbo decoder, we determined an optimal wordlength of Turbo decoder. Second, we suggested the MAP decoding algorithm based on sliding-window method which reduces the system memory significantly. By computer simulation, we could demonstrate that the suggested fixed-point Turbo decoder operates well with negligible performance loss.

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와이블-역승법을 이용한 기계류부품의 가속시험 방법 개발 (Development of accelerated life test method for mechanical components using Weibull-IPL(Inverse Power Law) model)

  • 이근호;김형의;강보식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.445-450
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    • 2003
  • This study was performed 10 develop the accelerated life test method using Weibull-IPL(Inverse Power Law) model for mechanical components. Weibull-IPL model is concerned with determining the assurance life with confidence level and the accelerated life test time From the relation of weibull distribution factors and confidence limit, the testing times on the no number of failure acceptance criteria arc determined. The mechanical components generally represent wear and fatigue characteristics as a failure mode. IPL based on the cumulative damage theory is applied effectively the mechanical components to reduce the testing time and to achieve the accelerating test conditions. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% confidence level for one test sample. According to IPL, because test time call be shorten in case increase test load test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7.

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Eye Tracker를 활용한 페이스북상에서 공감 정도가 사용자 시선에 미치는 영향 (The effect of Empathy in Eye vision to users in Facebook using an Eye Tracker)

  • 김수완;신동희
    • 디지털콘텐츠학회 논문지
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    • 제15권3호
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    • pp.387-393
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    • 2014
  • 본 연구는 세계에서 가장 많은 사용자들이 사용하고 있는 소셜네트워크 서비스인 페이스북에 중점을 두고 연구를 진행하였다. 페이스북상에서 사용자들에게 보여지는 콘텐츠들이 이용자들 개개인의 정서에 따라 차이점이 있을 것이라는 의문을 시작으로 실제 '공감'이라는 감정에 초점을 두어 연구를 진행하였다. 이러한 공감적인 요소는 페이스북 상에서 노출되는 콘텐츠 내에 실제 어떠한 영향을 미치는지에 대해 텍스트 중심과 이미지 중심의 콘텐츠로 분류를 하였고, 사람의 시선 이동을 측정하는 안구추적기(Eye-Tracker)를 통하여 공감 정도에 따라 선호하는 콘텐츠와 그 영향력을 보다 과학적인 방법으로 접근하고자 하였다. 해당 연구를 통하여 실제 사용자들에게 노출되는 페이스북 콘텐츠의 공감 정도에 따른 더 효과적인 콘텐츠를 제공하고자 하며, 실제 이용자들의 시선과 공감여부를 측정하는 일반공감척도를 이용하여 앞서 수집한 Eye-Tracker자료와 비교분석 하고자 한다.

ENHANCEMENT THE SOUND TRANSMISSION LOSS OF POROELASTIC LININGS

  • Song, B.Heuk-Jin;Bolton, J.Stuart
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.606-611
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    • 2000
  • It has been noted that the low frequency absorption coefficient of a porous sample placed in a standing wave tube is affected by the nature of the sample's edge constraint. The edge constraint has the effect of stiffening the solid phase of the sample, which itself can be strongly coupled to the material's fluid phase, and hence the incident sound field, by viscous means at low frequencies. In recent work it has also been shown that such a circumferential constraint causes the low frequency transmission loss of a layer of fibrous material to approach a finite low frequency limit that is proportional to the flow resistance of the layer and which is substantially higher than that of an unconstrained sample of the same material. However, it was also found that the benefit of the circumferential edge constraint was reduced in a transitional frequency range by a shearing resonance of the sample. Here it will be shown that the effect of that resonance can be mitigated or eliminated by adding additional axial and radial constraints running through the sample. It will also be shown that the constraint effect can be modeled closely by using a finite element procedure based on the Biot poroelastic theory. Implications for low frequency barrier design are also discussed.

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Mies van der Rohe 건축에서 나타난 재료의 표현특성에 관한 연구 (The Study on the Characteristics of Material appeared in the Architecture of Mies van der Rohe)

  • 이병욱;김용승;박용환
    • 한국실내디자인학회논문집
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    • 제13권6호
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    • pp.12-19
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    • 2004
  • Mies van der Rohe is still known as the architect whose influence is the largest among modem architects. As his work is typical of modern architecture, the architecture of Mies shows an interest in materials and techniques, even though It established the new architectural world by glass and iron, and only transparency is emphasized with glass. So it is blame for the loss of peculiarity a result of thinking In the way of sachlich with expression and structure of material and hierarchical relation. Vincent Scully has insist on that an appearance of modem architecture be occur not by simply a technical request of a technician but by reflection of the times and times' spirit. In this means, the works of Mies is the trial to express the new times' spirit that the new times order and an understanding of material properties about glass with new material of modern. For that, this study tries to consider that Mies'work is the new trial through reflection of material to express about the bstraction beyond the limit of sachlich expression, on the point of expresslonal characteristics of material shown in plan of the Barcelona Pavilion and skyscraper and on the basis of the theory of Gottfried Semper and Karl Boetticher that architectural surface Is a medium which can define space and also express mass.