• Journal of Construction Engineering and Project Management
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• 제8권1호
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• pp.1-9
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• 2018

US transportation agencies are dealing with shrinking budgets, limited work forces, and deteriorating infrastructure. In order to cope with funding uncertainty, state highway agencies are now looking into their own organizations and identifying programs, practices, and processes that have potential for cost saving. A quality assurance (QA) program is an integral part of highway construction and ensures a project's contracted level of quality. The cost of quality (conforming and nonconforming) can constitute a sizable part of total construction cost. As the quality assurance programs evolved, various practices and processes were developed over time and later adopted by state highway agencies. These practices and processes include different QA standards and specifications, varying testing methods, central testing lab vs. on site testing, performance based vs. prescribed quality assurance practices, implementation of innovative quality assurance practices, etc. Therefore, there is an opportunity to assess different QA strategies and recommend those practices that are effective and cost efficient. A national survey was conducted by the authors, which provided a detailed mapping of various QA practices and processes used as part of QA programs and identified areas where agencies can focus on for cost savings. The survey found that QA sampling and testing plans, optimization of sampling plans, optimization of QA standards and specifications, and implementation of innovative test methods and processes are the main areas the agencies should focus to lean the current QA programs.

• 상하수도학회지
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• 제32권5호
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• pp.421-434
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• 2018

Water supply/intake pumps operation use 70~80% of power costs in water treatment plants. In the water treatment plant, seasonal and hourly differential electricity rates are applied, so proper pump scheduling can yield power cost savings. Accordingly, the purpose of this study was to develop an optimal water supply pump scheduling scheme. An optimal operation method of water supply pumps by using genetic algorithm was developed. Also, a method to minimize power cost for water supply pump operation based on pump performance derived from the thermodynamic pump efficiency measurement method was proposed. Water level constraints to provide sufficient disinfection performance in a clearwell and reservoirs were calibrated. In addition, continuous operation time constraints were calibrated to prevent frequent pump switching. As a result of optimization, savings ratios during 7 days in winter and summer were 4.5% and 5.1%, respectively. In this study, the method for optimal water pump operation was developed to secure disinfection performance in the clearwell and to save power cost. It is expected that it will be used as a more advanced optimal water pump operation method through further studies such as water demand forecasting and efficiency according to pump combination.

• 경영과정보연구
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• 제31권4호
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• pp.309-337
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• 2012

오늘날의 시장은 기술의 진보로 인하여 과거에는 기대할 수 없던 여러 가지 기능을 제공할 수 있게 되었고 뛰어난 접근성과 반응은 고객이 원하는 때에, 원하는 물건을, 원하는 방식으로 살펴볼 수 있도록 제공해주어 고객의 욕구를 만족을 스스로 결정할 수 있는 구조를 가능하게 한다. 즉, 고객에게 스스로의 가치기준에 맞는 선택의 기회를 부여함으로서 만족을 달성하는 이러한 서비스를 TBSS (Technology-Based Self-Service)라 할 수 있다. 본 연구에서는 TBSS를 이용한 배송서비스 산업에서의 고객 만족 및 재구매의도 향상의 선행요인을 탐구하는 이론적 모형을 제안하고자 한다. 구체적으로 고객 만족과 재구매의도에 영향을 주는 지각된 가치를 '편익-비용'으로 구성하고 결과 편익과 과정 편익, 금전적 비용과 비금전적 비용의 영향력 크기를 비교하는 연구를 수행할 것이며 이를 통해 TBSS가 고객만족도 및 재구매 의도에 미치는 영향을 확인하고 유용성을 판단하는 본 연구의 결과가 고객 만족 및 재구매 의도 제고를 위한 실무적 정보를 제공하는데 도움이 되기를 기대한다.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.166-173
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• 2022

The introduction of acellular dermal matrix (ADM) to breast reconstruction has allowed surgeons to reexplore the prepectoral implant placement technique in postmastectomy breast reconstruction. Our institution adopted a novel approach using meshed ADM to lessen the financial burden of increased ADM utilization with the prepectoral breast reconstruction. This is a retrospective, single-center review of two-stage prepectoral breast reconstruction using meshed human-derived ADM for anterior prosthesis coverage. Patient demographics, oncologic data, perioperative characteristics, and complications were examined and reported as means with standard deviations. Cost-saving with the meshed technique was evaluated. Forty-eight patients (72 breasts) with a mean age of 48.5 ± 15.0 years (range 26-70 years) were included in the study. The mean follow-up time was 13.2 ± 4.4 months (range 4.1-25.8 months). Nineteen breasts (24.6%) experienced complications, with seromas being the most common complication (12.5%, n = 9). Expander removal and reoperation occurred at a rate of 8.3 and 9.7%, respectively. The average time to drain removal was 18.8 ± 6.6 days (range 8-32 days). Meshed ADM provided an average cost savings of $6,601 for unilateral and $13,202 for bilateral reconstructions. Our study found that human-derived meshed ADM can be safely used in two-staged prepectoral tissue expander-based breast reconstruction and can result in significant cost savings.

• Structural Engineering and Mechanics
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• 제49권1호
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• pp.65-80
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• 2014

This paper reports on the development of a minimum cost design model and its application for obtaining economic designs for reinforced High Strength Concrete (HSC) T-sections in bending under ultimate limit state conditions. Cost objective functions, behavior constraint including material nonlinearities of steel and HSC, conditions on strain compatibility in steel and concrete and geometric design variable constraints are derived and implemented within the Conjugate Gradient optimization algorithm. Particular attention is paid to problem formulation, solution behavior and economic considerations. A typical example problem is considered to illustrate the applicability of the minimum cost design model and solution methodology. Results are confronted to design solutions derived from conventional design office methods to evaluate the performance of the cost model and its sensitivity to a wide range of unit cost ratios of construction materials and various classes of HSC described in Eurocode2. It is shown, among others that optimal solutions achieved using the present approach can lead to substantial savings in the amount of construction materials to be used. In addition, the proposed approach is practically simple, reliable and computationally effective compared to standard design procedures used in current engineering practice.

• 전기학회논문지
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• 제62권1호
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• pp.21-28
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• 2013

The paper proposes an optimal sizing method of a customer's battery energy storage system (BESS) which aims at managing the electricity demand of the customer to minimize electricity cost under the time of use(TOU) pricing. Peak load limit of the customer and charging and discharging schedules of the BESS are optimized on annual basis to minimize annual electricity cost, which consists of peak load related basic cost and actual usage cost. The optimal scheduling is used to assess the maximum cost savings for all sets of candidate capacities of BESS. An optimal size of BESS is determined from the cost saving curves via capacity of BESS. Case study uses real data from an apartment-type factory customer and shows how the proposed method can be employed to optimally design the size of BESS for customer demand management.

• 한국항만경제학회지
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• 제20권2호
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• pp.217-234
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• 2004

Information technology has been transforming the relationship between shippers and carriers, but an unresolved question remains: what is the relative importance to shippers of service versus cost benefits of e-logistics solutions? This research develops and empirically tests a model to determine how Internet-based logistical operations in international shipping impact on the relative importance of cost versus service benefits to shippers. Contrary to expectations, results show that shippers perceived cost benefits from well-designed web sites, undoubtedly a consequence of perceptions that multi-function portals with ease of access contributed to savings in time and money. Another result was the confirmation of the positive effects of cargo tracing and bill of lading issuance on service-related factors. Finally, this study draws attention to the need for improvements in on-line booking capabilities and development of a comprehensive common portal; issues that must be addressed for shipping lines to succeed in an increasingly competitive e-logistics market.

• 경영과학
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• 제17권3호
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• pp.31-47
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• 2000

The widespread diffusion of Internet has enables companies to conduct business in quite a different way. marketing on the Internet becomes more important as firms adopt electronic commerce as a means to implement competitive strategies. One hundred and four BC shopping mall companies responded to an e-mail and web server survey about the anticipated benefits of electronic commerce and related strategies. The survey also asked about improvements in value chain activities and impediments to the implementation of electronic commerce in Korea. The results indicated that Korean shopping mall companies followed differentiation strategy significantly more than the other two strategies. In addition, six benefits factors were drawn from this study - information, productivity, cost savings, customers, management information, and applications. Productivity factor was related to cost leadership strategy, and customers factor was related with cost leadership, differentiation and focus strategies. Several benefits factors were also correlated with value chain activity improvements. The results of this study were compared with those of research conducted in the United States.

• 조명전기설비학회논문지
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• 제25권1호
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• pp.59-63
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• 2011

In small-power applications, variable-speed motors having high efficiency and controllability become more dominant than brushed DC motors. BLDC motors with permanent magnets in the rotor and SRMs directed by reluctance torque due to no permanent magnets have been strongly studied as a candidate. Compared to the BLDC motors, SRMs are more suitable for low-cost applications since the magnetic structure is simple, mechanically robust, and cheap due to no additional excitation in the rotor such as copper wire, aluminum, and permanent magnets. In addition, relatively small number of phases in single and two-phase SRMs allows more cost savings with regards to material in the motor and switching devices in the converter. In this paper, several 2 phase SRMs are compared to a 3 phase 6/4 SRM in terms of flux distribution in key parts of the motors.

• Journal of Communications and Networks
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• 제8권1호
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• pp.123-131
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• 2006

Several distributed architectures, incorporating mobile agent technology, have been recently proposed to answer the scalability limitations of their centralized counterparts. However, these architectures fail to address scalability problems, when distributed tasks requiring the employment of itinerant agents is considered. This is because they lack mechanisms that guarantee optimization of agents' itineraries so as to minimize the total migration cost in terms of the round-trip latency and the incurred traffic. This is of particular importance when MAs itineraries span multiple subnets. The work presented herein aspires to address these issues. To that end, we have designed and implemented an algorithm that adapts methods usually applied for addressing network design problems in the specific area of mobile agent itinerary planning. The algorithm not only suggests the optimal number of mobile agents that minimize the overall cost but also constructs optimal itineraries for each of them. The algorithm implementation has been integrated into our mobile agent framework research prototype and tested in real network environments, demonstrating significant cost savings.