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Preventive Replacement Model Based on Substitutive Characteristics : the case of periodic observation (대용특성을 이용한 예방정비모형 : 주기적으로 관측하는 경우)

  • Gu, Ja-Hang;Jang, Jung-Sun;Kim, Won-Jung
    • Journal of Korean Society for Quality Management
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    • v.20 no.2
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    • pp.33-43
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    • 1992
  • Items are assumed to fail by degradation. An appropriate stochastic model of such item is a cumulative process in which an item can fail only when the total amount of wear exceeds a prespecified failure level. This paper presents replacement policy in which an item is replaced at a certain level of wear before failure or at failure, whichever occurs first. Yet, when measuring the item wear level is very expensive, destructive or time-consuming, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. The item's wear level could usually be estimated by monitoring such substitutive characteristics only except for a breakdown, which may be observed immediately at its occurrence. The purpose of this paper is to find an optimal periodic replacement policy based on such substitutive characteristics that balance the cost of replacement with the cost of failure and result in a minimum total long-run average cost per unit time. The optimal level of substitutive characteristics to replace the item is obtained. Numerical example illustrate how the model can be used to determine the optimal replacement policy.

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The Effect of Test Anxiety,Intelligence, and Item Arrangement Order on Test Performance in Earth Science (시험불안(試驗不安) 지능(知能) 및 문항배렬(問項配列) 방식(方式)이 지구과학(地球科學) 의험수행(議驗遂行)에 미치는 효과(效果))

  • Kim, Sang-Dal;Yi, Hyang-Sun;Hwang, In-Ho
    • Journal of The Korean Association For Science Education
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    • v.11 no.2
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    • pp.161-178
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    • 1991
  • This study was designed to investigate the effect of test anxiety, intelligence, and item arrangement order on test performance in Earth Science. The main purposes in this study were to investigate (1) (2) (3) (4) on test performance.: (1) the effect of test anxiety components on test performance in Earth Science. (2) the effect of item arrangement order on test performance in Earth Science. (3) the effect of test anxiety This study was designed to investigate the effect of test anxiety, intelligence, and item arrangement order on test performance in Earth Science. The main purposes in this study were to investigate (1) (2) (3) (4) on test performance.: (1) the effect of test anxiety components on test performance in Earth Science. (2) the effect of item arrangement order on test performance in Earth Science. (3) the effect of test anxiety components on test performance in Earth Science according to learner's intelligence levels. (4) test effect of item arrangement order on learner's intelligence. The hypothesis was that there is difference among test achievements scores according to (1) test anxiety-worry levels. (2) item arrangement orders. (3) item arrangement orders on test anxiety-worry levels. (4) test anxiety-worry levels on intelligence levels. (5) test anxiety-emotionality levels. (6) item arrangement orders on test anxiety-emotionality levels. (7) test anxiety-emotionality levels on intelligence levels. (8) item arrangement orders on intelligence levels. The test items selected for this study were derived from the text Science (part 1) first grade of high school. The subjects of this study were 164 of high school first grade boy students in Pusan. They were assigned to one of the three groups, according to test anxiety levels.: (1) upper 25% of total subjects designated to high group (2) middle 50% (3) low group, lower 25% of total subjects And according to LQ. (1) upper 25% of total subjects designated to high group. (2) middle 50%. (3) low group, lower 25% of total subjects Analysis of variance was used in this study for hypothesis examination. The dependent variable was the achievement scores of Earth Science test and independent variables were test anxiety(worry, emotionality) level, LQ. level, item arrangement orders. The principal findings of the present study are as follows: (1)Test achievement score trend decreases as the test anxiety (worry, emotionality) increases although the result is not statistically significant. (2)There is no significant difference among test achievement scores according to item arrangement orders. (3)The higher the LQ. is, the more effective test anxiety. And the LQ. has significant interaction effect with test anxiety. (4)There is significant interaction effect between the LQ. levels and itemqr arrangement orders.

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Regional Assessment of the Effect of the Win-Win Item Agreements (대형마트 상생품목제도 영향의 지역적 평가)

  • Yoo, Byong-Kook;Kim, Soon-Hong
    • Journal of Distribution Science
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    • v.13 no.10
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    • pp.93-99
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    • 2015
  • Purpose - It has been argued that the regulations restricting entry and opening hours of General Super Markets and Super Super Markets have not been as effective as expected. In contrast, the win-win item scheme that appeared recently has the advantage that it could raise the effectiveness of the system in that win-win items are in principle resigned on the basis of bilateral agreements. This study analyzes the win-win item agreement made between Homeplus at Hap-jung and small traditional markets to examine the practical effectiveness of the win-win item scheme. While existing literature studying the regulatory effects have concentrated on the restrictions around store entry or opening hours of large retailers, it can be said that there have been few empirical studies on the effect of win-win items agreement with large retailers. Research design, data, and methodology - Homeplus at Hap-jung made a win-win items agreement with nearby small traditional market traders in 2013. In accordance with this voluntary agreement, Homeplus started by limiting its sales to 15 win-win items. The survey was conducted through one-on-one interviews, April 14 to May 2, 2014, by a professional public opinion research agency. The interviews were targeted at small business retailers in the nearby traditional market. We divided the traditional markets near Homeplus at Hap-jung where the win-win item agreement was achieved into two groups, win-win item agreement markets and non win-win item agreement markets, to compare the performance difference between the two groups. Results - To determine the change in sales of the 15 win-win items, we examined the performance difference between the two groups using two criteria (compared with similar items, and compared to sales volume a year ago). The results show that the individual sales of win-win items in the win-win item agreement markets are more likely to increase than in the non win-win item agreement markets. Total sales volume of individual stores in the agreement markets also showed a more significant increase compared to a year ago than those in non win-win item agreement markets. Conclusions - Contrary to the existing retail regulations that have one-sided and uniform characteristics, it can be pointed out that the win-win item scheme has the effect of increasing the success of the system itself because it is done on the basis of mutual agreement between General Super Markets and traditional markets. The empirical results of this study can be said to support this conjecture. For the successful settlement of a win-win items agreement, the following points should be reviewed. First, it requires a great effort from the selection process of win-win items in order to improve the effectiveness of the agreement. Second, the existing General Super Markets customers should be introduced to the traditional markets or small shops to increase the sales of win-win items. Therefore, voluntary effort is essentially required from the traditional markets to engage customers.

STEP 기반 자동차 PDM

  • 오유천
    • Proceedings of the CALSEC Conference
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    • 1997.11a
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    • pp.443-461
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    • 1997
  • ㆍProSTEP, PDES, Inc., and JSTEP announce agreement on PDM Schema ㆍ November 4, 1997 ㆍInteroperable with STEP AP203, AP2l0, AP214, and AP232 ㆍNeutral specification allows for the exchange of the following types - item master data (part identification, approval of part version) - item structure - item classification - item property (mass, costs) - document management (identification, revision… ) - work management (engineering change request, EC order, project) ㆍVendors of PDM systems are asked to join ProSTEP's PDM Round Table and PDES, Inc.'s PDMnet.(omitted)

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Design and Implementation of Item pool-Based Program using Visual Basic (비주얼베이직을 이용한 문항중심 프로그램의 설계 및 현황)

  • 문병원;박순철
    • Proceedings of the IEEK Conference
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    • 2003.07d
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    • pp.1371-1374
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    • 2003
  • This paper designs and implements of Item pool-Based Program using Visual Basic, a sort of self- study system. This paper is implemented the system which makes and remakes the test items using item-pool data with different method from an ordinary fixed form of evaluation. This system helps teachers to make a various test type of items by searching data through the item-pool and accounting it to the test items. This system will also improve the learner's understanding of the problems and desire for self-solving a problem.

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Preventive Replacement Models Based on Substitutive Characteristics (대용특성을 이용한 예방정비모형)

  • Gu, Ja-Hang;Kim, Won-Jung;Jang, Jung-Sun
    • Journal of Korean Society for Quality Management
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    • v.20 no.1
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    • pp.59-67
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    • 1992
  • This paper deals with preventive replacements models for the item whose failures are dependent on their wear level. When measuring the item wear level is very costly, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. In this paper, replacement policies based on such substitutive characteristics are proposed. The optimal level of substitutive characteristic to replace the item, which minimizes total cost, is obtained. Some numerical examples are also given.

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A Dimensionality Assessment for Polytomously Scored Items Using DETECT

  • Kim, Hae-Rim
    • Communications for Statistical Applications and Methods
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    • v.7 no.2
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    • pp.597-603
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    • 2000
  • A versatile dimensionality assessment index DETECT has been developed for binary item response data by Kim (1994). The present paper extends the use of DETECT to the polytomously scored item data. A simulation study shows DETECT performs well in differentiating multidimensional data from unidimensional one by yielding a greater value of DETECT in the case of multidimensionality. An additional investigation is necessary for the dimensionally meaningful clustering methods, such as HAC for binary data, particularly sensitive to the polytomous data.

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Transactions Clustering based on Item Similarity (아이템의 유사도를 고려한 트랜잭션 클러스터링)

  • 이상욱;김재련
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2002.11a
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    • pp.250-257
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    • 2002
  • Clustering is a data mining method, which consists in discovering interesting data distributions in very large databases. In traditional data clustering, similarity of a cluster of object is measured by pairwise similarity of objects in that paper. In view of the nature of clustering transactions, we devise in this paper a novel measurement called item similarity and utilize this to perform clustering. With this item similarity measurement, we develop an efficient clustering algorithm for target marketing in each group.

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Optimum Free Warranty Interval for Repairable Items (수리가능한 아이템의 최적무상보증기간)

  • 정영배
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.21 no.45
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    • pp.301-307
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    • 1998
  • This paper proposes free warranty interval for repairable items when the failure types of item are considered. Failure types are classified into major failure and minor failure. If major failure occurs during warranty period, the item is replaced and if minor failure occurs during warranty period, the item is minimally repaired. This paper determines the optimum free warranty interval which minimizes total expected cost of the free warranty cost model. Numerical example is shown in which failure time of item has weibull distribution.

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A Fast Algorithm for Mining Association Rules in Web Log Data (상품간 연관 규칙의 효율적 탐색 방법에 관한 연구 : 인터넷 쇼핑몰을 중심으로)

  • 오은정;오상봉
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2003.11a
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    • pp.621-626
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    • 2003
  • Mining association rules in web log files can be divided into two steps: 1) discovering frequent item sets in web data; 2) extracting association rules from the frequent item sets found in the previous step. This paper suggests an algorithm for finding frequent item sets efficiently The essence of the proposed algorithm is to transform transaction data files into matrix format. Our experimental results show that the suggested algorithm outperforms the Apriori algorithm, which is widely used to discover frequent item sets, in terms of scan frequency and execution time.

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