• 대한산업공학회지
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• 제32권3호
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• pp.163-171
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• 2006

This paper considers a scheduling problem to minimize the sum of the associated scheduling (production/delivery times) cost and the delivery cost for an integrated system of a single production machine and various transportation vehicles with transportation mode selection allowed. Each transportation mode is provided with a fixed number of vehicles at the associated delivery time and cost. The proposed problem is characterized as being NP-hard. Some solution properties are also characterized. Therewith, three heuristic algorithms (called SPT-based, LWF-based and WSPT-based heuristic) and a branch-and-bound algorithm are derived. In order to evaluate the effectiveness and efficiency of the proposed algorithms, computational experiments are made with some numerical instances.

• Advances in aircraft and spacecraft science
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• 제10권5호
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• pp.393-418
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• 2023

Drones are increasingly used in logistics delivery due to their low cost, high-speed and straight-line flight. Considering the small cargo capacity, limited endurance and other factors, this paper optimized the pickup and delivery vehicle routing problem with time windows in the mode of "truck+drone". A mixed integer programming model with the objective of minimizing transportation cost was proposed and an improved adaptive large neighborhood search algorithm is designed to solve the problem. In this algorithm, the performance of the algorithm is improved by designing various efficient destroy operators and repair operators based on the characteristics of the model and introducing a simulated annealing strategy to avoid falling into local optimum solutions. The effectiveness of the model and the algorithm is verified through the numerical experiments, and the impact of the "truck+drone" on the route cost is analyzed, the result of this study provides a decision basis for the route planning of "truck+drone" mode delivery.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1456-1461
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• 2004

Companies of Build-to-Order(BTO) strive to achieve customer responsiveness and cost efficiency simultaneously. The success of BTO depends upon the high volume production based on product plat form and delayed differentiation principle on the one hand, and upon the rapid estimation of delivery and cost for the customer orders on the other hand. Expeditious processing of a specific order requires the rearrangement of production resources and the schedule, which results in increased cost. This paper describes a cost estimation method using activity-based costing depending on the schedule change caused by urgent customer orders.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.223-226
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• 2001

This paper suggest a fast multimedia delivery system. by using accelerated video. The system can delivery multimedia data faster and more effectively than previous delivery system. By using accelerated video, users can get information by least cost, and internet delivery server can send maximum information on limited bandwidth.

• 대한토목학회논문집
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• 제33권6호
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• pp.2575-2582
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• 2013

공공건설공사 발주제도 운영에 있어 기술경쟁을 지향하는 턴키 및 대안방식 등 설계 시공일괄방식의 경우, 시설물의 품질향상 및 건설기술 발전에 기여하였음에도 불구, 계약되는 공사비가 설계 시공 분리발주방식을 적용하는 공사보다 높아 예산낭비 우려가 있다는 지적과 함께 수주독점, 입찰담합, 심의비리 등의 문제가 쟁점이 되고 있다. 그러나 실제 발주방식별 사업성과와 효과에 대해 정밀 비교분석한 사례가 없는 실정이며, 단순히 낙찰률 등 사업의 한정된 일반적 정보만으로 사업효과를 논의하고 판단하는 것은 자칫 오류를 범할 우려가 있다. 이에 공공 건설공사를 대상으로 계약에서 준공에 이르기까지 실제 집행한 공사비 자료를 광범위하게 조사하여 비용의 투입구조 및 변동추세 등 발주방식별 특성을 비교분석하고 공공건설공사 발주제도의 올바른 이해와 효율적 운영을 도모하고자 한다.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.332-337
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• 2013

Various project delivery methods have been utilized by owners over the years to maximize project performance. The design-build delivery method is being increasingly used due to the advantages it can offer to an engineering construction industry. Numerous studies have advocated the use of design/build over the traditional design/bid/build delivery approach. This study represents comprehensive analysis of 40 projects from the construction industry and shows that design/build method may not provide all the benefits to project performance. This study found timesaving was a definitive advantage of design/build project delivery, but the positive effects of cost changes was not convincing. Based on the results of the study, the project management expertise and experience of the contractor may have a greater impact on project performance outcomes than focusing on project delivery strategy only.

• 한국군사과학기술학회지
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• 제20권3호
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• pp.345-351
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• 2017

A wind tunnel test for the scaled parachute models was performed to verify aerodynamic characteristics for practical usage of Korean low cost low altitude aerial delivery system. The cruciform shaped cargo parachute models for heavy and light weight were ejected into wind tunnel test section; and the drag forces acting on the models in steady condition were measured in accordance with velocity. Also, the maximum opening forces during inflation were obtained and captured by a high speed camera to analyze the inflation characteristics and evaluate the design of the low cost aerial delivery system. The results showed a reliable stability and met the design requirement of delivery operation system for R.O.K Air Force.

• 산경연구논집
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• 제10권10호
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• pp.45-51
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• 2019

Purpose - The purpose of this study was to propose a win-win development plan for not only suppliers of delivery applications but also traditional market vendor companies and delivery riders by analyzing existing delivery models and presenting a new delivery model to enhance competitiveness of the traditional market using delivery apps. Research desgin, data, and methodology - Specifically, small retailers, such as traditional markets and supermarkets, presented a compromised delivery model that utilizes the platform of specialized delivery app service providers for order reception, and that the delivery is delivered by delivery systems jointly hired by Vendor companies, such as franchising companies. To validate the significance of the trade-off delivery model, a cost-benefit analysis was conducted by those involved in the delivery application. Results - From the perspective of suppliers of specialized delivery applications, it is analyzed that the use of specialized delivery applications in traditional markets will be a new market opportunity for service providers to achieve increased sales. It is expected that consumer choice and satisfaction will be increased as convenience and accessibility of traditional market businesses that were available only through direct visit from the user side of the delivery application will be expanded. From the standpoint of delivery application franchises, it is analyzed that they can seek to increase sales and increase customer service as well as ease labor cost burden due to joint employment of delivery riders. The delivery rider will be able to seek to improve customer service due to job security, wage stability, risk reduction and overheated competition due to direct employment. Conclusion - In conclusion, the compromised delivery model solved the problems raised in the preceding study conducted on delivery application suppliers, users, franchises, and riders to establish that it could be a strategic alternative to increasing sales and expanding detailed rights for the self-employed in the traditional market, which are experiencing difficulties in management. However, the adoption of a compromise delivery model requires social consensus from those involved in the delivery application and requires legal, institutional and policy support, which will require continued follow-up research on the delivery model in the future.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.81-91
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• 2014

Widely spreading smart devices have become an important information sharing channel in everyday life. In particular, social networking services (SNS) are the hub for content creation and sharing. Users post their contents on SNS servers and receive contents of interest. Contents are delivered in either pull or push. Regarding delivery, cost and wait time are two important factors to be minimized, but they are in a trade-off relationship. The Push-N-scheme (PNS) and timeout-based push scheme (TPS) have been proposed for content delivery. PNS has an advantage in cost over TPS, whereas TPS has an edge in terms of the wait time over PNS. We propose a hybrid push scheme of PNS and TPS, called push-N-scheme with timeout (PNT), to balance the cost and the wait time. We evaluate PNT through simulations, with the results showing that PNT is effective in balancing PNS and TPS.

• 한국경영과학회지
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• 제41권3호
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• pp.75-96
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• 2016

This paper investigates the usefulness of drones in an urban delivery system. We define the vehicle and drone routing problem with time window (VDRPTW) and present a model that can describe a dual mode delivery system consisting of drones and vehicles in the metropolitan area. Drones are relatively free from traffic congestion but have limited flight range and capacity. Vehicles are not free from traffic congestion, and the complexity of urban road network reduces the efficiency of vehicles. Using drones and vehicles together can reduce inefficiency of the urban delivery system because of their complementary cooperation. In this paper, we assume that drones operate in a point-to-point manner between the depot and customers, and that customers in the need of fast delivery are willing to pay additional charges. For the experiment datasets, we use instances of Solomon (1987), which are well known in the Vehicle Routing Problem society. Moreover, to mirror the urban logistics demand trend, customers who want fast delivery are added to the Solomon's instances. We propose a hybrid evolutionary algorithm for solving VDRPTW. The experiment results provide different useful insights according to the geographical distributions of customers. In the instances where customers are randomly located and in instances where some customers are randomly located while others form some clusters, the dual mode delivery system displays lower total cost and higher customer satisfaction. In instances with clustered customers, the dual mode delivery system exhibits narrow competition for the total cost with the delivery system that uses only vehicles. In this case, using drones and vehicles together can reduce the level of dissatisfaction of customers who take their cargo over the time-window. From the view point of strategic flexibility, the dual mode delivery system appears to be more interesting. In meeting the objective of maximizing customer satisfaction, the use of drones and vehicles incurs less cost and requires fewer resources.