• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.111-119
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• 1995

In this paper, we propose an efficient SA(simulated annealing) algorithm for the synthesis of binary phase computer generated hologram. SA algorithm is a method to find the optimal solution through iterative technique. It is important that selecting cost function and parameters within this algorithm. The aplications of converentional SA algorithm to synthesize parameters within this algorithm. The applications of conventional SA algorithm to synthesize binary hologram have many problems because of inappropriate paramters and cost function. So, we propose a new cost function and a calculation technique of proper parameters required to achieve the optimal solution. Computer simulation results show that the proposed method is better than conventional method in terms of diffraction efficiency and reconstruction error. Also, we show the reconstructed images by the proposed method through optical esperiment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.10-22
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• 2010

The first full-scale u-City operation has started in Dongtan u-City. As local cities take over and operate the u-City, unexpected issues arise such as securing the budget of operating costs and self-providing the costs with business models utilizing the u-City assets. The paper presents a strategy for solving these issues. The strategy provides a foundation(infrastructure) for long-term operation models which may reduce the long-term operating costs. In order to establish the economic operating framework of u-City, suggested are some cost-reduction models based on the operating costs structure. For each model, a base framework with comparative analysis of operating costs is provided. With these models, each u-City may select a relevant model according to the characteristics of it. We hope that the framework provides the foundation for efficient and sustainable u-City operations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.9
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• pp.27-35
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• 1994

It is known that a unified phase I-phase II semi-infinite optimization algorithm with a steerign parameter performs better than the original unified phase I-phase II algorithm. In this paper, the effect of the steering parameter is analized and a new algorithm is presented based on the facts that when the point x is far away from the feasible region, reaching to the feasible region is more important than minimizing the cost functio and that when the point x is near the region, it is more efficient to try to reach the feasible region and to minimize the cost function concurrently. It is also important to consider the relationship between the feasible direction and the gradient of the cost function. Even though changing the steering parameter does not change the rate of convergence of the algorithm, it is shown from examples that given new algorithm is more efficient than the previous ones.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1310-1319
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• 2010

This paper has shown that Linear Induction Motor(LIM) and Rack and pinion type are efficient in selecting railway routes and systems after considering time, geo-spatial characteristics and the floating population by benchmarking domestic and overseas mountain trains. The benefit-cost analysis through the use of modeling on user's willingness to pay is conducted as a means that provides access to tourism resources. this paper concludes that the benefit-cost varies in response to changes in the amount of user's willingness to pay by age. It is expected that this paper serves as a reference data in the introduction stage of the mountain train project implemented by central or local governments with tourism resources in mountainous areas as the mountain train has turned out to be economically efficient while various potential benefits that have not been included in the benefit-cost analysis need to be quantified and remain to be studied further.

• Magazine of korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.26-35
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• 2020

Tunnelling to bypass major landslide areas is considered as a good and long-term environmentally friendly solution to reduce an existing hazard. In Norway, hundreds of kilometres of tunnels have been constructed in areas prone to landslides and snow avalanches. Although tunnelling is considered as an expensive mitigation strategy for bypassing landslides, analysis indicate that in some cases the cost of building a tunnel can be repaid by savings in driving costs (fuel) alone over a period of 5-10 years due to reduced driving distances. The other benefits of constructing tunnels in landslide areas include savings in time and increased safety. The Norwegian Method of Tunnelling (NMT) is considered safe, efficient and cost effective compared to other tunnelling techniques. Some aspects of NMT, which are considered safe and cost efficient, are presented. The application of updated rock support techniques, including reinforced ribs of shotctrete (RRS), which is a key component of the Norwegian Method of Tunnelling (NMT), is highlighted.

• Proceedings of the Safety Management and Science Conference
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• 2002.11a
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• pp.17-23
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• 2002

Value can be defined as function divided by cost. The ultimate goal of VE (Value Engineering) is to simultaneously reduce cost and to enhance function in given projects. In general, there are eight phases (Selection, Investigation, Speculation, Evaluation, Development. Presentation, Implementation, and Audit) to perform VE. This paper presents analysis of important factors for VE in construction fields using QFD (Quality Function Deployment) technique. QFD was introduced in 1972 to help design supertanker in Mitsubish's shipyards in Kob, Japan and formally defined by the American Supplier Institute in 1987 as a system for translating consumer requirements into appropriate company requirements at every stage, from research, through product design and development, to manufacture, distribution, installation, and marketing, sales and services. The objective of this paper is to provide and analyze the trend on the viewpoint of efficient value engineering of field workers. The data are collected by questionnaires. The samples for this study are chosen from 13 companies in Korea during 2 months (2002. 7 ∼ 2002. 8). The results of this study will play an important role not only for the efficient value engineering but also for preparing of life cycle cost analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2626-2634
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• 1997

The purpose of multicasting is to reduce the network costs for transmitting the same traffic to multiple destinations. In this paper, an efficient delay-bounded multicasting routing algorithm is proposed, which satistifies the network conditions of cost minimization and can adjust the dynamic events, such as 'leave and/or join ones' from the multicast group. Also, our algorithm is designed for various network requirements such as the efficiet dynamic group support, high-quality data distribution, and adaptability to variable situation. After the delay tolerance and the maximum group size are determined according to network state and requirements for delay and cost, the dynamic delay-bounded multicast tree is constructed using partial multicast routing. We evaluate the performance of the proposed algorithm by running simulations on randomly generated test networks using a Sun Sparc 20 workstation. We were able to obtain good simulation resutls, which means solutions that lies between the minimum cost solution and the minimum delay one.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1145-1150
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• 2008

In this paper, We studied efficient design of wireless transmission system for unified data transmission in a subway and railway. It is increased that need of broadband multimedia service to make useful environment for user and to support the operation of railway system. High bandwidth is better if we need more services. But, high bandwidth requires more cost at tunnel of subway. More bandwidth make receive sensitivity to bad. So it need more wireless Station. We deduced best bandwidth of subway wireless transmission system reflecting the cost of installation and efficiency of system. Consequently, we decide efficient service model of broadband wireless system at a subway. Subway broadband wireless transmission system is tested in this year, and it is to be extended to province subway. Cost of subway broadband wireless transmission system is saved, because the system can be efficiently designed. Therefore, the effectiveness is expected to be very big.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5885-5889
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• 2013

In general, the network survivability means that The user do not know the network faults and the recovery of those. For this, we use the dual(multi) routes between each two nodes. It is important that the each dual routes have efficient costs(or minimum). Even if one route is the minimum cost in case of no fault, another route of dual may be very large cost in case of fault case. Therefore we need the dual routes of each two nodes having the efficient(or minimum) costs. In this paper we find the network design method for the dual routes of each two node having the efficient costs. Although the design method is very simple and heuristic and it may be not useful for some networks, we will use it in various network environment.. Because this design method can be used very easy. A sample design will proof this usefulness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.10
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• pp.867-873
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• 2013

Competition policy for growth and activation of market should consider structural nature of relevant industry closely. In this viewpoint, whether domestic MNOs(mobile network operators) are competing while securing the effect of scale economies and maximum production efficiency is an important element when looking for competition policy means of domestic mobile communication market. With this, present study analyzed level of MES (Minimum Efficient Scale) and whether achieving them or not through investigating the relation between the cost per minute and call traffic of domestic MNOs. This analysis is differentiated from existing econometric studies entailing several assumptions by enhancing a reality reflection through directly deducing of cost curve using verified data(cost per minute and call traffic). As a result of analysis, the levels of minimum efficient scale were different from each other between domestic MNOs, and an incumbent MNO(SKT) accomplished minimum efficient scale while entrant MNOs(KT and LGU+) could not yet reach minimum efficient scale level. This result demonstrates a gap exists in production efficiency level among domestic MNOs and implies that the policy to alleviate the gap among operators is required when establishing competitive policy in the future.