• 산업경영시스템학회지
• /
• 제41권1호
• /
• pp.110-117
• /
• 2018

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called 'preventive maintenance policy.' Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

• 한국태양에너지학회 논문집
• /
• 제22권4호
• /
• pp.97-106
• /
• 2002

The purpose of this study is to analyze the life cycle cost of primary cooling system by systematic support cost. Life Cycle Cost(LCC) is the process of making an economic assessment of an item, area, system, or facility by considering all significant costs of ownership over an economic life, expressed in terms of equivalent costs. The essence of life cycle costing is the analysis of equivalent costs of various alternative proposals. In order to select economical primary cooling system in early heat source plan stages, the research investigates cost items and cost characteristics during project process phases such as planning/design, construction, maintenance /management, and demolition/sell phases. The study also analyze the life cycle cost by capacity leading to suggest the most economical primary cooling system by systematic support cost.

• 한국건설관리학회논문집
• /
• 제9권6호
• /
• pp.235-243
• /
• 2008

건설산업은 발주자가 생산활동(시공) 이전에 소요되는 비용을 예측하여 수급자에게 도급주는 형식을 취한다. 따라서 공사비 예측은 건설 프로젝트 전 단계에 걸쳐 수차례 이루어져야 하며, 발주자와 수급자 모두에게 중요하다. 그러나 국내의 경우 단가물량내역 완료전 공사비 예측은 실적자료를 이용한 면적당 단가방식을 벗어나지 못하고 있으며 이를 보완하기 위한 정형화된 절차와 방법이 미비한 것이 현실이다. 이에 본 연구는 국내 공공 아파트 사업 주동을 대상으로 수량기반 공사비 분석 방법인 면적형 세대별 수량분석 방법을 제안하고 데이터베이스를 구축한 후 유효성과 세목수량 예측중심 공사비 예측방법의 적용성을 확인하였다. 이로써 건설프로젝트 전체 라이프사이클에 대한 공사비정보의 일관성 있고 상호 연계된 관리가 가능할 것으로 예상되며, 예측 결과가 세목 수량과 단가의 곱으로 이루어져 각종변경 및 연계확보, 시점의 변화, 제도의 변화에 탄력적으로 적용될 수 있다. 따라서 본 연구는 건설 공사비정보를 수량기반 데이터 형태로 집 관리할 수 있는 방법을 제시하고 그 효용성을 확인하였다는데 그 의미가 있다.

• 품질경영학회지
• /
• 제11권1호
• /
• pp.10-17
• /
• 1983

본 연구에서는 제품의 수명시험을 수행하는데 있어서 수명이 지수분포를 따를 때의 결과를 [1]제품의 MTBF가 $T_1$인 경우, 검사에 통과될 확률 $1-{\alpha}$(${\alpha}$는 생산자 위험), 제품의 MTBF가 $T_2$인 ($T_1$ > $T_2$) 경우, 검사에 통과될 확률 ${\beta}$(${\beta}$는 소비자 위험)로 하여 수명이 Weibull 분포(Shape Parameter를 알고 있을 때)를 따를 때에로 확장하였다. 또한, 수명시험과 관계있는 검사특성곡선(QC curve)과 평균수명시험시간(Average Life Testing Time)을 구해 보았다. 비용분석은 [1]의 과정을 그대로 활용하였다. 위의 전 과정은 Level II Basic Language로 Programming하여 Micro-Computer를 이용하여 계산하였다. 본 연구와는 다른 관점에서 Weibull 분포의 수명시험계획을 다루었던 [6]의 결과는 모두 같은 방향 - 지수분포에 비해 수명시험시간의 절감 - 으로 귀결되었음을 알 수 있다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제16권10호
• /
• pp.1010-1014
• /
• 2010

잡지기사 관련 상품 연계 추천 서비스는 온라인 상에서 잡지 가사의 컨텍스트를 반영하여 상품을 추천하는 서비스이다. 현재 이러한 서비스는 잡지기사와 상품에 부여되어 있는 태그 간의 유사성을 기준으로 한 추천 기술에 의존하고 있으나, 태그 부여 비용과 추천의 정확도가 높지 않은 단점이 있다. 본 논문에서는 잡지 기사 컨텍스트 관련 상품연계 추천 기술의 한 요소로서 상품이미지 정보로부터 상품의 종류를 자동으로 분류하고 이를 상품의 태그로 활용하는 방법을 제안한다. 이미지에서 추출한 시각단어(visual word)와 상품 종류 간의 고차 연관관계를 하이퍼네트워크 기법을 통해 학습하고, 학습된 하이퍼네트워크를 이용하여 상품 이미지에 한 개 이상의 태그를 자동으로 부여한다. 실제 온라인 쇼핑몰에서 사용되는 10 가지 종류의 상품 1,251개의 이미지 데이터를 기반으로, 하이퍼네트워크 이용한 상품이미지 자동 태깅 기법이 다른 기계학습 방법과 비교하여 경쟁력 있는 성능을 보여줌과 동시에, 복수개의 태그 부여를 통해 상품 이미지 태깅의 정확성이 향상됨을 보인다.

• 대한치위생과학회지
• /
• 제3권2호
• /
• pp.1-8
• /
• 2020

This study investigated the relationship between oral health knowledge, behavior and orthodontic satisfaction in orthodontic patients visiting dental hospitals and clinics and provided suggestions to improve orthodontic patients' satisfaction. This study anayzed structured self-administered questionnaires collected from 245 patients who visited 5 dental clinics in Gwangju Metropolitan City. Regarding oral health knowledge, the highest percentage of correct answers was for the item "Cavities heal themselves over time" (97.1%), and the lowest percentage of correct answers was for the item "Cavity bacteria move from tooth to tooth" (16.7%). Five fluoride items showed a lower percentage of correct answers than those for cavity and gingival diseases. Regarding the survey on oral health behavior, the highest score was found for the item "I brush my teeth with a certain method and order" (3.78 out of 5), and the lowest score was found for the item "I use an electric toothbrush" (1.34 out of 5). Regarding the survey on orthodontic satisfaction, the highest score was found for the item "I would recommend receiving medical treatment at the department of orthodontics" (4.23), and the lowest score was found for the item "Orthodontic cost is reasonable" (3.46). While oral health behavior had on orthodontic satisfaction, oral health knowledge had no effect on it. Oral health behaviors should be improved to enhance orthodontic satisfaction. To improve oral health behavior, it is necessary to develop and activate education programs for tooth brushing and oral care for orthodontic patients.

• 국제학술발표논문집
• /
• The 2th International Conference on Construction Engineering and Project Management
• /
• pp.711-720
• /
• 2007

Apartment housing in the Korean domestic construction industry has had various and high-quality finishing work since the enforcement of price deregulation in 1998. Before the enforcement of price deregulation, feasibility studies of housing projects have not had particular difficulties as uniform description of finishing work items were reflected and finishing work cost also was equalized. However, the recent distinction of finishing work based on the same floor plan brings about project cost variation, along with many effects on construction management due to project cost increment. Accordingly, this paper suggests the improved plan of cost management to control the feasibility study result consistently during the life cycle of a project through an analysis based on cost management phase due to cost blackout, appearing at the commencement of a project, cost gradation caused by high-quality finishing work item, and cost reduction due to the degradation of finishing work after analysis of current apartment construction process focused on finishing work using the IDEF process analysis technique.

• 국제학술발표논문집
• /
• The 2th International Conference on Construction Engineering and Project Management
• /
• pp.30-40
• /
• 2007

The demand for light-rail construction projects has recently been increasing, and they are mostly supervised by private construction companies. Therefore, a private construction company that aim to raise gains from the operation of the facilities during the contract period greater than what they invested should b able to accurately calculate the costs from the aspect of Life Cycle Cost (LCC). In particular, a light-rail transit bridge that has a heavier portion from the aspect of the cost of light-rail transit construction requires a more accurate calculation method than the conventional LCC calculation method. For this, an LCC analysis model was developed and a cost breakdown structure was suggested based on literature review. The construction costs by shape of the upper part of a light-rail transit were calculated based on the cost breakdown system presented in this paper, and the cost generation cycle and cost unit price were collected and analyzed based on records on maintenance costs, rehabilitation and replacement. In addition, after forming some hypotheses in order to perform the LCC analysis, economic evaluation was conducted from the aspect of the LCC by using performance data by item.

• 대한산업공학회지
• /
• 제17권1호
• /
• pp.51-58
• /
• 1991

This paper presents a single-echelon, single item, stochastic lead time and static demand inventory model for situations in which, during the stockout period, a fraction ${\beta}$ of the demand is backordered and the remaining fraction $(1-{\beta})$ is lost. In this situations, an objective function representing the average annual cost of inventory system is obtained by defining a time-proportional backorder cost and a fixed penalty cost per unit lost. The optimal operating policy variables minimizing the average annual cost are calculated iteratively. At the extremet ${\beta}=1$, the model presented reduces to the usual backorder case. A numerical example is solved to illustrate the algorithm developed.

• International Journal of Reliability and Applications
• /
• 제7권1호
• /
• pp.71-77
• /
• 2006

The market for second hand products has been growing for a variety of reasons (e.g., new products appearing at a faster rate and the expected life of products increasing due to rapid advances in technology). The demand for warranties for second-hand products has been growing along with the growth of the market for second-hand products. Warranty for new products (consumer durables, industrial and commercial, and specialized defense products) has received a lot of attention. In contrast, warranties for second-hand product have received very little attention. Often, dealers of second-hand product such as cars offer 2D-warranties (Year and Kilometers). The expected warranty cost associated with a second-hand product for 2D-Policies is a function of the age of the item and its usage (as it affects failures over the warranty period), the warranty terms and the servicing strategy used by the dealer. This paper deals with development of models for warranty cost analysis along with the decision on sale price and warranty cover for 2D-Warranty policies associated with sale of second-hand products.