• International Journal of Advanced Culture Technology
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• 제8권1호
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• pp.62-70
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• 2020

As an effective means of price discrimination, some suppliers offer trade credit to the distributors in order to stimulate the demand for the product they produce. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. Since the distributor's lot-size is affected by the demand for the customer, the distributor's lot-size and the selling price determination problem is interdependent and must be solved at the same time. Also, in many common business transactions, the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. In this regard, we deal with the joint lot-size and price determination problem when the supplier allows delay in payments for an order of a product. The positive effects of credit transactions can be integrated into the EOQ (economic order quantity) model through the consideration of retailing situations, where the customer's demand is a function of the distributor's selling price. It is also assumed that the distributor's order cost consists of a fixed ordering cost and the variable shipping cost. We formulate the distributor's mathematical model from which the solution algorithm is derived based on properties of an optimal solution. A numerical example is presented to illustrate the algorithm developed.

• Journal of Information Processing Systems
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• 제17권3호
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• pp.489-504
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• 2021

By distributing computing tasks among devices at the edge of networks, edge computing uses virtualization, distributed computing and parallel computing technologies to enable users dynamically obtain computing power, storage space and other services as needed. Applying edge computing architectures to Internet of Vehicles can effectively alleviate the contradiction among the large amount of computing, low delayed vehicle applications, and the limited and uneven resource distribution of vehicles. In this paper, a predictive offloading strategy based on the MEC load state is proposed, which not only considers reducing the delay of calculation results by the RSU multi-hop backhaul, but also reduces the queuing time of tasks at MEC servers. Firstly, the delay factor and the energy consumption factor are introduced according to the characteristics of tasks, and the cost of local execution and offloading to MEC servers for execution are defined. Then, from the perspective of vehicles, the delay preference factor and the energy consumption preference factor are introduced to define the cost of executing a computing task for another computing task. Furthermore, a mathematical optimization model for minimizing the power overhead is constructed with the constraints of time delay and power consumption. Additionally, the simulated annealing algorithm is utilized to solve the optimization model. The simulation results show that this strategy can effectively reduce the system power consumption by shortening the task execution delay. Finally, we can choose whether to offload computing tasks to MEC server for execution according to the size of two costs. This strategy not only meets the requirements of time delay and energy consumption, but also ensures the lowest cost.

• 한국항공운항학회지
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• 제8권1호
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• pp.57-66
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• 2000

Benefit-cost analysis is one of key elements of feasibility study on a large scale investment for transportation infrastructure improvements. Benefit-cost analysis requires measuring expected benefits after the investment is completed. Reduction of delays is the major source for the benefit among other measurable benefits. Measurement methods for delays reduction have been reviewed and two methods were recommended for passenger delay and aircraft operation delay. Using these method, the effects of Cheju International Airport Improvement Projects were evaluated.

• 한국건설관리학회논문집
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• 제6권4호
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• pp.80-90
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• 2005

프로젝트의 일정 네트워크는 선-후행 관계로 정의된 액티 비 티들로 구성되어 있다 액티비티를 완료하는데 소요되는 기간은 다양한 단축-지연 원인들에 의해 임의적이고, 확률-통계적 인 특성을 지닌다. 이러한 특성은 최종공사기간을 불확실하게하며, 재무리스크의 주요인이 된다. 본 연구는 선행 연구에서 개발된 확률-통계적 일정 시뮬레이션 시스템(Stochastic Project Scheduling Simulation)을 확장하여 액티비티 기간이 임의적으로 변동함에 따라 최종공사비가 어떻게 거동하는지 추정하는 방법론을 제시한다. 액티비티 기간을 임의의 변수로 취급하였고, 액티비티에 할당된 직접공사비에 공사기간의 단축-지연에 따른 간접비의 증감을 반영하여 최종공사비를 추정하였다. 액티비티 기간의 변동에 따라 의존 변수인 간접비가 변동하는 특성을 고려하여 시뮬레이션 출력값들(최종공사기간들)의 통계적 특성을 정량적으로 분석하여 최종공사비를 추정하였으며, 예비할 필요가 있는 지체보상금의 정도를 정량화하였다. 기존의 결정론적 기법이 불확실성을 내재한 체 지체 보상금의 비율을 주관적으로 적용해 왔던 반면, 본 연구에서 제시된 기법은 확실성과 신뢰도를 가지고 지체보상금의 비율을 책정할 수 있도록 하는 방법론을 제시하고 있다. 하나의 예제 프로젝트가 시뮬레이션을 이용한 정량분석기법을 예시하기위해 사용되었으며, 불확실성을 내포하고 있는 액티비티 기간들이 최종공사비에 미치는 영향을 검증하기위해 시뮬레이션 모의실험을 실행하였다 자동화된 민감도분석 기법을 이용하여 액티비티 기간을 정의하는 확률분포함수의 통계적 위치를 변화시킴에 따라 최종공사기간 및 최종공사비가 어떠한 거동을 나타내는지 확인하였다. 예제로 사용된 표본 프로젝트에 내재되어있는 재무리스크에 대응하기위해 지체보상금을 어느 정도까지 보유할 필요가 있는지를 정량적으로 분석하고, 의사결정을 위해 어떻게 적용될 수 있는지를 소개한다. 본 연구에 제시된 기법은 연구자들 및 현업 종사자들에게 최종공사비 예측에있어서 액티비티 기간 변화의 확률적 영향과 이론적 의미를 밝힘으로 프로젝트 자본계획과 관련된 위기관리에 진보된 예측방법론을 제공한다.

• 한국도로학회논문집
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• 제19권5호
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• pp.153-162
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• 2017

PURPOSES : This study was conducted to analyze the effects arising from extending the duration of nighttime road construction on improving road quality and durability. METHODS : Most previous studies estimating the social cost of various construction conditions did not consider road pavement cooling time as a factor in improving road pavement quality. This study investigated the feasibility of achieving higher road quality and durability by extending the duration of nighttime road construction time extension. For this investigation, the effects of such an extension on traffic conditions were analyzed based on micro-simulation studies and scenario-based cost-benefit analyses, using factors including traffic volume, delay, construction cost, and road pavement cooling time. RESULTS : The results of the traffic simulation studies and cost-benefit analyses indicate that the current road construction method that emphasizes completing nighttime road construction by 6 a.m. reduces pavement life while causing relatively little traffic delay. If the night construction time is instead extended to 2 p.m., road pavement lifetime is increased, reducing road re-construction cost. These savings are greater than the cost of congestion arising from extending the duration of nighttime construction. CONCLUSIONS : The current nighttime construction durations need to be extended in order to efficiently manage roads and reduce road management costs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.27.2-27
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• 2001

This paper proposes a receding horizon predictive control (RHPC) for nonlinear time-delay systems. The control law is obtained by minimizing finite horizon cost with a terminal weighting functional. An inequality condition on the terminal weighting functional is presented, under which the closed-loop stability of RHPC is guaranteed, A special class of nonlinear time-delay systems is introduced and a systematic method to find a terminal weighting functional satisfying the proposed inequality condition is given for these systems. Through a simulation example, it is demonstrated that the proposed RHPC has the guaranteed closed-loop stability for nonlinear time-delay systems.

• 한국건축시공학회지
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• 제21권4호
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• pp.347-359
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• 2021

최근 건설공사는 초대형화로 단일 공사규모가 복잡해지고 천문학적인 공사비가 소요되는 프로그램 관리 형태의 성격을 지니는 사업이 등장하고 있다. 특히, 대규모 건설사업과 같이 프로그램 수준에서 관리가 절대적으로 필요한 사업은 계획된 일정 및 비용에 대한 전제적인 관리가 필요하다. 하지만 국내의 경우 구체적인 공사지연에 관한 관리기준이 부재한 현실이다. 이에 본 연구에서는 대규모, 장기간 진행되는 프로그램 수준의 대규모 건설사업을 성공적으로 수행하고 공정지연 및 부진사업을 사전에 방지하기 위한 지연관리지수(Delay Management Index, DMI)를 개발하였다. 이를 통해 대규모 복합건설 프로젝트를 대상으로 사례연구를 수행하였으며, 프로그램 수준 건설사업을 위한 지연예방체계를 구축하였다.

• 전기학회논문지
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• 제57권3호
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• pp.458-465
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• 2008

In this paper, we propose a non-fragile guaranteed cost controller design method for uncertain linear systems with constant delyas in state. The norm bounded and time-varying uncertainties are subjected to system and controller design matrices. A quadratic cost function is considered as the performance measure for the system. Based on the Lyapunov method, an LMI(Linear Matrix Inequality) optimization problem is established to design the controller which uses information of delayed state and minimizes the upper bound of the quadratic cost function for all admissible system uncertainties and controller gain variations. Numerical examples show the effectiveness of the proposed method.

• 한국경영과학회지
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• 제25권3호
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• pp.81-89
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• 2000

The real-time multicast problem is to construct a multicast tree starting from a source node and including multiple destination nodes and that has minimum network cost with delay constraints. It is known that to find a tree of the minimum network cost is the Steiner Tree problem which is NP-complete. In this paper, we propose a genetic algorithm to solve the multicast tree with minimum network cost and the delay constraints. The computational results obtained by comparing an existing algorithm. Kompella algorithm, and the proposed algorithm show that our algorithm tends to find lower network cost on the average than Kompella algorithm does.

• Management Science and Financial Engineering
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• 제16권3호
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• pp.1-20
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• 2010

In this paper, the impact of various system parameters such as the parameters of actual demand process, the review periods and the lead times, under each combination of inventory policies and information sharing, on the long run average inventory cost per period incurred at each participant in a supply chain, is considered. For this purpose, numerical studies are conducted, from which some valuable information as to how sensitive our long run average inventory cost per period are as the model parameters change is gleaned, from which, in turn, some managerial insights are gleaned in order for industry practitioners to perform better in supply chain management.