• 제목/요약/키워드: Item

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PH 수명분포를 갖는 보증제품의 수리-교체 전략 (Repair-Replacement Strategies for Warrantied Items with Phase-Type Lifetimes)

  • 김호균;배창옥;김승철
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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    • pp.686-691
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    • 2005
  • We are concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it by a new item. In this paper, we consider the repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

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선별후 양품의 비율에 대한 제약조건을 갖는 선별검사방식의 경제적 설계 (Economic Design of Screening Procedures under the Constraint on the Proportion of Conforming Items after Screening)

  • 홍성훈
    • 대한산업공학회지
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    • 제19권3호
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    • pp.25-35
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    • 1993
  • Economic screening procedures using a correlated variable are proposed to assure that the proportion of conforming items is above a desired level after screening. It is assumed that the performance variable and the screening variable are jointly normally distributed. Two screening procedures are considered. In the first screening procedure, all of the items are inspected on the screening variable. If an item fails to meet the screening specifications, it is rejected and excluded from shipment without inspection of the performance variable. In the second screening procedure, the item which fails to meet the screening specifications is inspected on the performance variable. If the value of the performance variable is within specifications the item is accepted, and the item is rejected otherwise. Cost models are constructed which involve cast from an accepted nonconforming item, cost from a rejected item, and quality inspection cost. Methods of finding optimal cutoff value on a screening variable are presented and numerical examples are given.

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PH 수명분포를 갖는 보증제품의 수리-교체 전략 (Repair-Replacement Strategies for Warranted Items with Phase-Type Lifetimes)

  • 김호균;;배창옥;김승철
    • 대한산업공학회지
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    • 제31권4호
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    • pp.341-348
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    • 2005
  • This paper is concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it with a new item. In this paper, we consider repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

Phase-Type 분포를 이용한 보증서비스 비용 분석 (Warranty Servicing Cost Analysis Using Phase-Type Lifetime Distributions)

  • 김호균;백천현;조형수
    • 한국경영과학회지
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    • 제25권3호
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    • pp.41-48
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    • 2000
  • We consider the question of warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it by a new item. In this paper, we consider a warranty policy for making this decision based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair/replacement decision. illustrative numerical examples are presented.

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인터넷 중고시장 이용 소비자의 쇼핑경험에 관한 자연주의적 접근 - 아이베이비를 중심으로 - (Investigation into Consumers' Shopping Experiences in Internet Used-item Markets - Focused on "I-baby" -)

  • 유현정
    • 대한가정학회지
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    • 제44권4호
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    • pp.175-190
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    • 2006
  • The purpose of this research is to investigate consumers' experience of using Internet used-item markets in order to determine their motives in such activity. In terms of the Internet used-item market, (1) it contributes to a sound culture of consumption by recycling, (2) as a C2C market, it retains characteristics fundamentally different from the existing one-way type of market, (3) and it offers different characteristics from existing offline-based flea markets. Two significant themes emerged from the study results. First, users of Internet used-item markets passed through various stages such as novice, addict, and expert and learned the techniques for utilizing the used-item market. Second, for fast transactions with generalized Internet banking and the increasing trend for price bargaining emotional exchange among members is being transformed into the pursuit of transactional efficiency.

복수품목 랜덤 결함주문정책의 최적해와 비교 (Optimal Solution and Comparison for the Augmented Multi-item Random Orders)

  • 권희철;김만식
    • 산업경영시스템학회지
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    • 제10권16호
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    • pp.129-132
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    • 1987
  • Multi-item inventory problems can be well characterized by the nature of interaction of the quantities and timing. This interaction may be due to the effect of certain combination of orders. It is that the set-up cost of ordering individual items can be saved by jointly ordering at a time. This study finds a decision criteria of optimum inventory policy through the comparisons of individual multi-item order policy(IMP), joint multi-item order policy(JMP), augmented multi-item order policy(AMP) in cost ratio. Subsequently we assume that there exists a unique optimum order level corresponding to an optimum reorder range for the augmented multi-item order, at which a cost saying is maximum.

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Collaborative Filtering Algorithm Based on User-Item Attribute Preference

  • Ji, JiaQi;Chung, Yeongjee
    • Journal of information and communication convergence engineering
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    • 제17권2호
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    • pp.135-141
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    • 2019
  • Collaborative filtering algorithms often encounter data sparsity issues. To overcome this issue, auxiliary information of relevant items is analyzed and an item attribute matrix is derived. In this study, we combine the user-item attribute preference with the traditional similarity calculation method to develop an improved similarity calculation approach and use weights to control the importance of these two elements. A collaborative filtering algorithm based on user-item attribute preference is proposed. The experimental results show that the performance of the recommender system is the most optimal when the weight of traditional similarity is equal to that of user-item attribute preference similarity. Although the rating-matrix is sparse, better recommendation results can be obtained by adding a suitable proportion of user-item attribute preference similarity. Moreover, the mean absolute error of the proposed approach is less than that of two traditional collaborative filtering algorithms.

응급구조과 학생의 윤리적 가치관에 관한 연구 (A Study of the Ethical Values of EMT students)

  • 김미선
    • 한국응급구조학회지
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    • 제5권1호
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    • pp.37-51
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    • 2001
  • This study is aimed at examining the ethical values of EMT students. The results below are based on the revised questionnaires, which can be applicable to EMT from the original questionnaires developed by Lee(1990), with a sample of 124 students consisting of 63 first and 61 second year students, conducted November 2-8, 2001. Data were analyzed using SPSS in terms of means, standard deviations, t-test, ANOVA, Pearson's correlation coefficient. The results are as follows: 1. In the area of Human life, all subjects showed utilitarian disposition. All respondents perceived the item "When patients recognizing there is no hope for survival ask for euthanasia, it is ethically right to accommodate their opinions." as the most utilitarian item, whereas they perceived the item "When an hopeless patient is on cardiac arrest, it is ethically right to do CPR as the most deontoogical item. 2. In the area of patient relationship, all students of two groups took on deontoogical characteristics, but there were no statistically significant differences between two groups. All students perceived an item "EMT have to keep it secret if patients disclose their suicide intentions and ask for absolute secrecy" the most utilitarian item, whereas they perceived an item "Even though patients act and speak in a very rude manner, EMT people should do their best to provide care for patients." as the most deontoogical item. 3. In the area of task relationship, first year students perceived an item "Given time limitations, it is ethically right to give priority to the patients who can be rehabilitated over the patients who can't be fully recovered." as the most utilitarian item, whereas second year students perceived an item "Under no circumstances should any placebo be administered to patients." as the most utilitarian item. All students perceived an item "When EMT students see an unconscious person lying in the street, they have to give him/her emergency treatment." as the most deontoogical item. 4. In the area of coworker relationship, all students of two groups took on deontoogical disposition, but there were no significant differences between two groups. All students of two groups perceived an item "Suppose you are regarded as the person who would be promoted. However, you think that your coworker is more competent than you. In that case you should tell your supervisor about your coworker." as the most utilitarian item. First year students perceived an item, whereas second year students perceived an item "When you observe coworkers' misconduct at work, it is ethically right to ignore their misdeeds." as the most deontoogical item. 5. This study demonstrated that for the first year students, there is a correlational relationship between areas of human life and task relationship, and between areas of task relationship and coworker relationship, whereas for the second year students, there is a correlational relationship between areas of human life and task relationship. 6. In areas of human life and task relationship, there are significant differences according to attitudes toward EMT and attendance at ethics training sessions. In the area of coworker relationship, there are significant differences according to religion, attendance at ethics training sessions, and a code of ethics. Recommendations for future research, 1. Sample items to measure ethical values and the instrument tailored to the needs of EMT should be developed. 2. A longitudinal study to track ethical value changes according to the amount of work experience is needed. 3. A code of ethics and/or ethics training, which could apply in actual situations, should be implemented.

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구조방정식 모델에서 항목묶음이 인과 모수의 검정과 적합도 평가에 미치는 영향 (The Effects of Item Parceling on Causal Parameter Testing and Goodness-of-Fit Indices in Structural Equation Modeling)

  • 조현철;강석후
    • 마케팅과학연구
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    • 제17권3호
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    • pp.133-151
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    • 2007
  • 본 연구에서는 3개 일반모델(general models)의 실증분석을 통해 항목묶음(item parceling)이 구성개념간의 인과관계를 나타내는 모수의 유의성 검정 결과 및 모델의 적합도 평가에 미치는 영향을 검토하였다. 연구 결과에 의하면, 개별항목을 적용한 분석과 비교할 때 항목묶음을 통한 분석을 적용해도 모델 인과모수의 검정통계량은 그다지 변하지 않으므로 유의성 검정 결과에도 변화가 없는 것으로 나타났다. 하지만 전반적 적합도지수의 측면에서는 RMSEA를 제외한 주요 모델 적합도 지수, 즉 GFI, AGFI, CFI 및 NFI의 값들이 상당히 개선되는 경향을 보였다. 주요 모델 적합도 지수들의 값이 높아진 것은 항목묶음을 이용하여 분석을 한 결과가 개별항목을 통한 분석의 결과에 비해 다변량 정규(분포)성의 개선 등으로 인해 높아진 것으로 해석된다. 하지만 항목묶음을 적용함에 있어서 주의해야 할 사항은 적용하기 전에 구성개념의 단일차원성(unidimensionality)을 우선적으로 검토해야 한다는 점이다. 본 연구에서는 항목묶음을 이용하여 분석을 할 경우 실제 구성개념간의 인과적 관계를 나타내는 모수의 유의성 검정과 모델의 적합도 지수들에 어떤 변화가 발생하는 지를 세 개의 일반모델을 대상으로 파악하였다.

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'정보 기술 기초' 교과의 문항 분석 - 대학수학능력시험 직업탐구영역을 중심으로- (Item Analysis of the 'Basic course of Information Technology' - Vocational Education Section in the College Scholastic Ability Test-)

  • 김종혜;김지현;김용;이원규
    • 컴퓨터교육학회논문지
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    • 제10권4호
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    • pp.39-49
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    • 2007
  • 본 연구는 대학수학능력시험 직업탐구영역의 "정보기술기초" 교과의 문항 특성 및 문항 양호도 분석을 통해 양질의 문항을 개발하기 위한 분석 자료로 제시하고자 한다. 질적 연구로 내용 타당도 분석을 하였고, 양적 연구로 문항의 난이도, 변별력, 신뢰도 및 오답지 분석을 하였다. 2005년, 2006년 "정보기술기초" 교과 문항 분석결과, 교과 내용이 골고루 출제되었으나 행동영역에 대한 기준이 제고될 필요가 있었다. 또한 "정보기술기초" 교과 문항이 대학수학능력시험에 적합하도록 양질의 문항 개발이 필요하였다. 그러기 위해서는 적절한 난이도와 변별력 있는 문항 개발에 대한 연구가 필요함을 알 수 있다.

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