• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.6
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• pp.2282-2303
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• 2021

To solve the problems of heavy computing load and system transmission pressure in energy internet (EI), we establish a three-tier cloud-edge integrated EI network based on a cloud-edge collaborative computing to achieve the tradeoff between energy consumption and the system delay. A joint optimization problem for resource allocation and task offloading in the threetier cloud-edge integrated EI network is formulated to minimize the total system cost under the constraints of the task scheduling binary variables of each sensor node, the maximum uplink transmit power of each sensor node, the limited computation capability of the sensor node and the maximum computation resource of each edge server, which is a Mixed Integer Non-linear Programming (MINLP) problem. To solve the problem, we propose a joint task offloading and resource allocation algorithm (JTOARA), which is decomposed into three subproblems including the uplink transmission power allocation sub-problem, the computation resource allocation sub-problem, and the offloading scheme selection subproblem. Then, the power allocation of each sensor node is achieved by bisection search algorithm, which has a fast convergence. While the computation resource allocation is derived by line optimization method and convex optimization theory. Finally, to achieve the optimal task offloading, we propose a cloud-edge collaborative computation offloading schemes based on game theory and prove the existence of Nash Equilibrium. The simulation results demonstrate that our proposed algorithm can improve output performance as comparing with the conventional algorithms, and its performance is close to the that of the enumerative algorithm.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.45-57
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• 2007

During the design phase of a system, which requires high reliability and safety such as aircraft, high speed train and nuclear power plant, reliability engineer must set up the target system reliability. To meet a reliability goal for the system, reliability allocation should be done gradually from the system to its element. For this end, first of all, we need to construct functional block diagram based on the design output and PWBS(Project Work Breakdown System). Another important input data for reliability allocation is the relationship between the cost and the reliability. In this study we investigate various reliability allocation models, which can be applicable to aircraft, vehicle, and power plant, and etc. And we suggest a proper reliability allocation model which can be effectively applicable to KTX-II high speed train to achieve the target system reliability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.162-163
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• 2016

This paper presents a mathematical model for optimizing earthwork allocation plan that minimizes earthwork cost. The model takes into account operational constraints in the real-world earthwork such as material-type (i.e., quality level of material) and quantities excavated from cut-sections, required quality of material and quantities for each embankment layer, top-down cutting and bottom-up filling constraints, and allocation orders. These constraints are successfully handled by assuming the rock-earth material as the three dimensional (3D) blocks. The study is of value to project scheduler because the model identifies the optimal earth allocation plan (i.e., haul direction (cut and fill pairs), quantities of soil, type of material, and order of allocations) expeditiously and is developed as an automated system for usability. It is also relevant to estimator in that it computes more realistic earthworks costs estimation. The economic impact and validity of the mathematical model was confirmed by performing test cases.

• IE interfaces
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• v.20 no.4
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• pp.427-437
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• 2007

As increasing the Internet traffic, many researches on access network are reported for end-to-end highspeed broadband network, where E-PON (Ethernet-Passive Optical Network) is one of reasonable candidates for the network with respect to cost and bandwidth utilization. For the high-speed access network, E-PON needs an efficient bandwidth allocation method. This paper describes a WFBA (Water-Filling Bandwidth Allocation) algorithm for the efficient bandwidth allocation with various simulation test. Based upon the simulation test, we suggest several ways to improve performance of E-PON.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.789-795
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• 2014

In a demand response (DR) market run by independent system operators (ISOs), load aggregators are important market participants who aggregate small retail customers through various DR programs. A load aggregator can minimize the allocation cost by efficiently allocating its demand response resources (DRRs) considering retail customers' characteristics. However, the uncertain response behaviors of retail customers can influence the allocation strategy of its DRRs, increasing the economic risk of DRR allocation. This paper presents a risk-based DRR allocation method for the load aggregator that takes into account not only the physical characteristics of retail customers but also the risk due to the associated response uncertainties. In the paper, a conditional value-at-risk (CVaR) is applied to deal with the risk due to response uncertainties. Numerical results are presented to illustrate the effectiveness of the proposed method.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.1-10
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• 2021

In recent decades, the heterogeneous and dynamic behavior of Internet traffic has placed new demands on the adaptive resource allocation of the optical network infrastructure. However, the advent of multifiber elastic optical networks has led to a higher degree of spectrum fragmentation than conventional flexible grid networks due to the dynamic and random establishment and removal of optical connections. In this paper, we propose heuristic routing and dynamic slot allocation algorithms to minimize spectrum fragmentation and reduce the probability of blocking future connection requests by considering the power consumption in elastic multifiber elastic optical networks.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.83-107
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• 2010

Urbanized environments are constructed to estimate peak flow and cost savings in response to possible BMP allocation at a watershed scale. The main goal is to explore the proper allocation of sub-watershed level BMPs for peak flow attenuation at a watershed scale. Since several individual site scale BMPs work as a form of aggregated BMPs at a sub-watershed scale, it is a question as to how to properly allocate the sub-watershed level BMPs at a watershed scale. The Hydrological Simulation Program-FORTRAN (HSPF) is set up for a hypothetically urbanized watershed. A peak flow is determined to be the primary variable of interest and targeted to characterize the spatial distribution of aggregated BMPs. Construction cost of a regional pond forms the basis of the economic valuation. The results indicate that when total size of BMPs is constant in the entire watershed, (1) it is most effective to have aggregated BMPs in some upper sub-watersheds while the BMPs in either the mainstem sub-watershed or a single sub-watershed are the least effective choices for peak flow attenuation at a watershed scale; (2) savings exist between allocation differences and reduced peak flow increases cost savings. The largest saving is found in the strategy of aggregated BMPs in some upper sub-watersheds. These findings, however, call for follow-up site specific case studies revisiting the watershed scale impacts of BMP allocation. Then, it will be argued that location and extent of decentralization are considerable policy variables for an alternative stormwater management policy at a watershed scale.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.194-200
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• 2007

The deregulation problem has recently attracted attentions in a competitive electric power market, where the cost must be earmarked fairly and precisely for the customers and the Independent Power Producers (IPPs) as well. Transmission loss is an one of several important factors that determines power transmission cost. Because the cost caused by transmission losses is about $3{\sim}5%$, it is important to allocate transmission losses into each bus in a power system. This paper presents the new algorithm to allocate transmission losses based on an integration method using the loss sensitivity. It provides the buswise incremental transmission losses through the calculation of load ratios considering the transaction strategy of an overall system. The performance of the proposed algorithm is evaluated by the case studies carried out on the WSCC 9-bus and IEEE 14-bus systems.

• Journal of Korean Society for Quality Management
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• v.43 no.1
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• pp.31-42
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• 2015

Purpose: System consists of a lot of units with coherent function. In design phase, various units could be considered with the same function. In this study, we consider the alternative units with the same function and redundancy allocation to maximize system reliability in multi level system. Methods: The redundancy allocation problem with the alternative units in multi level system is formulated. Memetic algorithm(MA) is proposed to optimize the redundancy allocation problem. In addition, the performance of the proposed algorithm is explained by a numerical experiment. Results: MA showed better results than genetic algorithm(GA) and the convergence of the solutions in MA was also faster than GA. In addition, we could know from experiment that system reliability is increased and the chosen unit for redundancy allocation is changed if cost limit is increased. Conclusion: The chose unit for redundancy allocation is changed as resource constraints. It means we need to consider the alternative units in system design. In the future, we need to consider various problem related to redundancy allocation in multi level system and develop the better method to enhance search performance.

• Journal of Digital Contents Society
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• v.3 no.2
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• pp.221-233
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• 2002

In this paper, we present integer programming models and algorithms for the Capacitated Facility Location-Allocation Problem (CFLP). The models and algorithms can be used for the design of logistics networks and for the location of telecommunication facilities. We are given a set of candidate facility installation sites, one type of facility for each candidate site with its capacity and installation cost, a set of customers with their demand requirement, and flow cost for one unit of demand flow from each customer to each candidate site. (CFLP) is to determine the number of facilities for each candidate site and the set of customers which are connected to each site with minimum cost, while satisfying the demand requirement of each customer and constraints imposed on the allocation of customers to facilities. We present two integer programming models for (CFLP), and devise a branch-and-cut algorithm and a branch-and-price algorithm for the problem.