• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.8
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• pp.375-387
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• 2005

This paper presents an application of parallel Genetic Algorithm-Tabu Search (GA-TS) algorithm to search an optimal solution of a service restoration in distribution systems. The main objective of service restoration of distribution systems is, when a fault or overload occurs, to restore as much load as possible by transferring the do-energized load in the out of service area via network reconfiguration to the appropriate adjacent feeders at minimum operational cost without violating operating constraints, which is a combinatorial optimization problem. This problem has many constraints with many local minima to solve the optimal switch position. This paper develops parallel GA-TS algorithm for service restoration of distribution systems. In parallel GA-TS, GA operators are executed for each processor. To prevent solutions of low fitness from appearing in the next generation, strings below the average fitness are saved in the tabu list. If best fitness of the GA is not changed for several generations, TS operators are executed for the upper $10\%$ of the population to enhance the local searching capabilities. With migration operation, best string of each node is transferred to the neighboring node after predetermined iterations are executed. For parallel computing, we developed a PC cluster system consists of 8 PCs. Each PC employs the 2 GHz Pentium IV CPU and is connected with others through ethernet switch based fast ethernet. To show the validity of the proposed method, proposed algorithm has been tested with a practical distribution system in Korea. From the simulation results, we can find that the proposed algorithm is efficient for the distribution system service restoration in terms of the solution quality, speedup, efficiency and computation time.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.327-331
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• 2009

Covering structures and elevated road of Cheonggyecheon are the by-products of the developing era when functionality and efficiency were emphasized. Historic river restoration project around Cheonggyecheon which had been emerged as a threat to the safety of the citizens due to its corrosion and structural defects as time passes had been performed during the period from July, 2003 through October, 2005 under the slogan of future-oriented urban environment creation. By dint of this river restoration project, its value is being heightened as almost all the rivers of Seoul including Seongbukcheon, Chungreungcheon and Honghaecheon have been arranged by inter-active linkage. In addition, this river is becoming a place frequented by the numerous visitors at home and aborad by providing the citizens with an attractive space for utilizing leisure time. Currently in the diversified areas, an academic research on the Cheonggyecheon restoration is under progress. In this study, sampled questionnaire for the visitors was carried out by site visit with the necessity of users' satisfaction survey in terms of revitalization of pedestrian space of the city street. As a result of this, natural restoration and provision of leisure space were surveyed to be highly assessed in terms of satisfaction and insufficient provision of convenience facilities including toilet and parking space was pointed out as a matter to be improved. As Cheonggyecheon is invigorated from the obstacle of urban environment through its epochal restoration, its value provided to us will be evaluated and by supplementing the deduced problems, we intend to find its meaning in our hope that this would become a sustainable future assets providing a basic data.

• Journal of Environmental Policy
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• v.11 no.3
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• pp.67-96
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• 2012

The Ministry of Environment in Korea has been promoting the urban stream restoration project for paved streams in cities as the restored Cheonggyecheon. As an elementary study for suggesting policy implications for the project, cost and benefit criteria for an ex-post analysis on the Cheonggyecheon project is suggested in this study. The ex-ante analysis were reviewed critically by focusing on the cost and benefit criteria. Ex-post analysis plan in this study is developed considering the standard guideline of pre-feasibility, the theory of cost-benefit analysis, and the review results. The costs for compensating lands, amending conflicts, researching rivers, and maintaining water quantity were also included. For the benefits, this study proposes to estimate the benefits with the assessment on naturalness of stream. The results are expected to contribute to increase the efficiency of the urban stream restoration project and evaluate the project to match better with the meaning of the river restoration.

• Current Optics and Photonics
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• v.7 no.3
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• pp.237-247
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• 2023

In middle- and long-distance imaging systems, due to the atmospheric turbulence caused by temperature, wind speed, humidity, and so on, light waves propagating in the air are distorted, resulting in image-quality degradation such as geometric deformation and fuzziness. In remote sensing, astronomical observation, and traffic monitoring, image information loss due to degradation causes huge losses, so effective restoration of degraded images is very important. To restore images degraded by atmospheric turbulence, an image-restoration method based on improved compound multibranch feature fusion (CMFNetPro) was proposed. Based on the CMFNet network, an efficient channel-attention mechanism was used to replace the channel-attention mechanism to improve image quality and network efficiency. In the experiment, two-dimensional random distortion vector fields were used to construct two turbulent datasets with different degrees of distortion, based on the Google Landmarks Dataset v2 dataset. The experimental results showed that compared to the CMFNet, DeblurGAN-v2, and MIMO-UNet models, the proposed CMFNetPro network achieves better performance in both quality and training cost of turbulent-image restoration. In the mixed training, CMFNetPro was 1.2391 dB (weak turbulence), 0.8602 dB (strong turbulence) respectively higher in terms of peak signal-to-noise ratio and 0.0015 (weak turbulence), 0.0136 (strong turbulence) respectively higher in terms of structure similarity compared to CMFNet. CMFNetPro was 14.4 hours faster compared to the CMFNet. This provides a feasible scheme for turbulent-image restoration based on deep learning.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.1-14
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• 2014

The purpose of this study is to identify the efficiency of LID technologies for controlling non-point source pollution from urban areas. The recent technical responses to managing water resource and urban areas according to the influence of climate change is an important national policy, along with green growth. Through various reference studies reasonable ways to consider a wholistic plan on urban-eco-friendly river management, the Low Impact Development (LID) as the adequate river management method is being undertaken in foreign countries to technically apply to urban plans. However, the LID is at the initial stage in Korea, with no specific studies implemented. Thus, this study explored whether LID technologies can be efficient measures to control non-point source pollution on the cost side. Ulsan's Namgu and Bukgu have been chosen as case studies that illustrate the efficiency of the LID technologies. On investigation, if LID technologies are designed properly, the efficiency of them is expected to higher than that of sewage treatment plant.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.936-938
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• 1997

Up to date, operator assistance systems -fault diagnosis system, fault restoration system etc.- are developed for power system automation. In this condition, an efficiency test of assistance system must be performed to prove application in real power system. This paper presents an SCADA simulator for an efficiency test of the operator assistance system, which is developed in the SCADA system. The proposed simulator is implemented under Win95 with Pentium-PC.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1288-1291
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• 1996

The submaterials are used for restoration of the impurities involved in iron ore. Robot system is constructed to measure the content of moisture in submaterials automatically, so we achieve the confidence of measuring work and the promotion of operation efficiency.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.5
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• pp.65-77
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• 2014

The ecosystem of Jaemin stream, flowing into the center of Gongju-si, had been damaged by low water quality and lack of water quantity of the steam. However, after applying the SSB (Sustainable Structured wetland Biotop) system to the flood plain and the upstream of Jaemin stream, the efficiency of ecological water purification and ecological restoration are as follows. Through the constant maintenance and monitoring from year 2009 to year 2013 after restorative design and construction the average influent concentration of BOD5 was 4.2 mg/L, and the average effluent concentration was 1.8 mg/L, reaching ecological water purification rate of 57%. As for the T-N, the average influent concentration was 9.983 mg/L, and the average effluent concentration was 6.303 mg/L, showing the rate of 37%. For the T-P, the average influent concentration was 0.198 mg/L, and the average effluent concentration was 0.098 mg/L, being the rate of 51%. The vegetation of Jaemin stream monitored for 2 years after the restoration was composed of 51 species in 28 families which show high ratio of planted native species. As for the animals in the site, 5 species in 3 families of reptiles and amphibians, 34 species of 23 families of birds, and 3 species in 2 families of mammals were monitored, indicating that the bio-diversity of the site has improved, as well.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.471-478
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• 2011

High resolution Pan-sharpening technique is becoming increasingly important in the field of remote sensing image analysis as an essential image processing to improve the spatial resolution of original multispectral image. The general scheme of pan-sharpening technique consists of upsampling process of multispectral image and high-pass detail injection process using the panchromatic image. The upsampling process, however, brings about image blurring, and this lead to spectral distortion in the pan-sharpening process. In order to solve this problem, this paper presents a new method that adopts image restoration techniques based on optimization theory in the pan-sharpening process, and evaluates its efficiency and application possibility. In order to evaluate the effect of image restoration techniques on the pansharpening process, the result obtained using the existing method that used bicubic interpolation were compared visually and quantitatively with the results obtained using image restoration techniques. The quantitative comparison was done using some spectral distortion measures for use to evaluate the quality of pan-sharpened image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.61-64
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• 2007

MPLS networks architectures have been prevailed as scalable approach to provide quality of service in the Internet. Many researches have been mainly focused on scalability and multi-path calculation scheme for failure restoration. However, the MPLS network have an scalability problem about traffic, and the existing failure restoration methods are wasted resources, and it has the problem that loss of a packet by a lot of delay occurs in too. Therefore in this paper, we propose a H-MPLS (Hierachical-Multiprotocol Label Switching)network for rapidly failure restorations and effective management of network extended. The proposed H-MPLS Network apply LSP multi-path routing algorithm and consists of several MPLS. After comparing the performance among the existing failure restoration methods with various network models, we use NS simulator in order to analyze the performance. Finally, we present an improvement scheme of the efficiency and scalability.