• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.479-487
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• 2013

State Highway Agencies (SHAs) have started utilizing cost-plus-time bidding (A+B bidding) since Federal Highway Agency (FHWA) declared it operational on May 4, 1995. Although this technique has successfully accelerated many projects by incorporating construction time in the bidding competition, a framework to illustrate the interactions of incentive/disincentive (I/D) rates on the competitiveness of contractors participating in the bid competition is yet to be developed. In a previous research, authors indicated that for each bid competition there is an efficient cap for I/D rates which are dictated by the capabilities of contractors in project acceleration. However, the results of previous study were based on the assumption that there is a statistically significant relationship between cost and time. In this study, the entire cost-plus-time projects implemented by the Oklahoma Department of Transportation (ODOT) were investigated. Then the significance of relationship between cost and time were analyzed for each contractor utilizing Analysis of Variance (ANOVA) technique, and the price-time function of each contractor was determined by regression analysis. The results of the analysis indicate that there is a significant relationship between cost and time for the majority of contractors. However, a quadratic relationship is not always significant and for some contractors a linear price-time relationship is significant. The results of this project can be used not only by ODOT to optimize the incentive/disincentive rates but also by contractors to determine the most competitive strategies of other bid participants.

• Architectural research
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• 제11권2호
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• pp.43-49
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• 2009

Since the late 1980s, the schedule technique applied to the construction industry around the world has rapidly changed from the traditional ADM (Arrow Diagramming Method) to the PDM (Precedence Diagramming Method) technique. The main reason for this change is to overcome the limits and inconveniences of the traditional ADM technique. The time-cost trade-off is one of the core scheduling techniques to establish the best optimized combination plan in terms of a relationship between the cost and schedule. However, most of the schedule-related textbooks and research papers have discussed and proposed applications of a time-cost trade-off technique based only on the Finish to Start relationship. Therefore, there are almost no consideration and discussion of problems or restrictions that emerge when the time-cost trade-off technique is applied to the PDM network that has overlapping relationships. This paper proposes the lead-time adjustment method as a methodology for overcoming some restrictions that are encountered when the time-cost trade-off technique is applied to the overlapping relationships of the PDM network.

• 한국건설관리학회논문집
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• 제10권3호
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• pp.130-138
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• 2009

Bromilow's time-cost (BTC) relationship was examined for building projects in Vietnam using actual construction time and total construction cost. Data set was collected from 77 historical building construction projects completed between 1999 and 2005 which were adjusted by consumer price index (CPI) to 2000 price. Time-cost equations were specified respected to two sectors, public and private, in Vietnamese construction industry and all cases. It is shown that a public funded building project has the longer construction duration than a similar budget private funded project. The resulting models are statistically significant. The adjusted R-square coefficients of all cases, public and private projects models are respectively 0.403, 0.436 and 0.377 mean that the BTC regression lines moderately fit the data set.

• Journal of Construction Engineering and Project Management
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• 제4권3호
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• pp.13-20
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• 2014

Estimating time and cost is an important mission in the early phase of a construction project, especially in feasibility study. It provides a foundation for making decision whether or not the project is performed on schedule and within budget. Thus, reliability of this estimate plays a key role in measuring the success of a project. This study was carried out to investigate the time-cost relationship in building construction projects in Bangladesh. The mathematical equation used in this study is based on Bromilow's equation. The research data were collected from sixty-three completed building projects through questionnaire survey. Type of clients, type of projects, and tender methods are the project characteristics considered in this study. The results of analysis indicated that the Bromilow's time-cost (BTC) models developed for each project characteristic are appropriate due to quite high coefficient of determination and relatively small mean percent errors. Among them, the forecasted model for time and cost according to tender methods is the best fit model. It is concluded that the BTC model could be applied in building construction project to predict its time and cost in Bangladesh. Four different regression models were also developed in this study. The results of BTC model between some selected countries were compared to gain the comprehensive view.

• 한국가정과교육학회지
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• 제12권1호
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• pp.1-9
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• 2000

The purpose of this study was to analyse the relationship between behaviors of the video game(frequency, time career) and related variables in middle and high school boys. The data were collected using questionnaires from 342 boys. The major results of this study are summarized as follows : (1) A correlation between the frequency and the time of video game was significant. but correlations between the career and the frequency. the time of video game were not significant. (2) The frequency of video game showed significant relationship with place. preference formation, relative preference. and parents involvement. The time of video game showed significant relationships with place. preference formation, relative preference, and cost. The career showed significant relationship with place and cost.

• Management Science and Financial Engineering
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• 제4권2호
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• pp.59-75
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• 1998

This paper presents an incentive system to reduce response time from a supplier. The incentive system is expressed as a contract between an assembler and a supplier who have a long-term relationship. We produce the optimal payment scheme and expected total cost, when the assembler is farsighted. We show that the farsighted assembler obtains higher effort level from the supplier than the myopic assembler. We also show that the expected total cost of the farsighted assembler is smaller in the long run, although it is initially higher than that of the myopic assembler.

• 벤처창업연구
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• 제1권2호
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• pp.101-134
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• 2006

본 연구는 온라인 쇼핑몰의 쿠폰판촉이 소비자의 구매행동에 미치는 영향을 검증하였다. 분석 결과는 다음과 같다. 첫째, 쿠폰 인지정도에 따라서는 F-검증을 실시한 결과 쿠폰의 인지여부에 딸 쿠폰 제공시 사용의사와 쿠폰 제공시 재사용의사에서는 유의미한 차이가 있는 것으로 나타났다. 둘째, 쿠폰의 사용경험에 따른 구매행동의 차이를 전체적으로 살펴보면 쿠폰사용 경험이 있다가 없다보다 높은 평균을 보여 유의미한 차이가 있는 것으로 나타났다. 이러한 결과는 쿠폰 사용경험에 따라 구매행동에 차이가 있음을 시사하고 있다. 셋째, 구매행동과 쿠폰의 비용/편익 자각의 관계를 살펴보면 뚜렷한 정적 상관관계가 있는 것으로 나타났다. 이는 쿠폰의 비용/편의 자각이 높을수록 구매행동이 높아짐을 의미한다. 넷째, 구매행동은 쿠폰사용을 즐김과 쿠폰 사용습관과 가장 관계가 높음을 발견하였다.

• 아동학회지
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• 제17권1호
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• pp.275-288
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• 1996

The purposes of this study were to investigate children's prosocial behavior by age and sex and to examine the relationship between children's prosocial moral reasoning and prosocial behavior by costs and types of tasks. The subjects were 300 3th-and 6th-graders enrolled in elementary schools in Seoul. The revised form of Prosocial Moral Dilemmas including costs and types of tasks was used. The tasks of prosocial behaviors included time-cost tasks, money-cost tasks and physical strength-cost tasks. For data analysis, the paired t-test, two-way ANOVA, and Pearson's Correlations were used. Major findings were as follows; (1)There was age difference in children's prosocial behavior. 6th-graders performed at a higher level than 3th-graders. Sex differences weren't significant. In low- and high-cost tasks and in time-, money-, and physical strength-cost tasks, there were (2) Scores on high-cost behavior tasks were higher than on low-cost tasks. (3) Children's prosocial moral reasoning was positively related to prosocial behavior; in low- and high-cost tasks, and in time-, money-, and physical strength-cost tasks.

• 산업공학
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• 제14권4호
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• pp.365-373
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• 2001

It is discussed how to determine time windows for pickups and deliveries, which have been assumed to be given in all most of previous studies on traveling salesman problems with time window, vehicle routing problems with time window, vehicle scheduling and dispatching problems, and so on. First, time windows are classified into four models (DR, DA, AR, and AA) by customers‘ polices. For each model, it is shown how a time window is related to various cost terms of suppliers and customers. Under the assumption of collaborative supplier-customer relationship, an integrated cost model for both supplier and customer is constructed for determining boundaries of time windows. The cost models in this paper consists of cost terms that depend on waiting time, early arrival time, late arrival time, and rejection of receipt. A numerical example is provided and results of the sensitivity analysis for some parameters are also provided to help intuitive understanding about the characteristics of the suggested models.

• Journal of Construction Engineering and Project Management
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• 제1권1호
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• pp.37-43
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• 2011

Labor productivity is a significant factor associated with controlling time, cost, and quality. Many researchers have developed models to define methods of measuring the relationship between productivity and various parameters such as the size of working area, maximum working hours, and the crew composition. Most of the previous research has focused on estimating productivity; however, this research concentrates on estimating labor productivity and developing time and cost data for repetitive concrete pouring activity. In Korea, "Standard Estimating" only entails the average productivity data of the construction industry, and it is difficult to predict the time and cost spent on any particular project. As a result, errors occur in estimating duration and cost for individual activities or projects. To address these issues, this research sought to collect data, measure productivity, and develop time and cost data using labor productivity based on field conditions from the collected data. A probabilistic approach is also proposed to develop data. A case study is performed to validate this process using actual data collected from construction sites. It is possible that the result will be used as the EVMS baseline of cost management and schedule management.