• Journal of the Korean GEO-environmental Society
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• v.15 no.7
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• pp.59-66
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• 2014

Nowadays, some studies are performed in order to introduce the Limit State Design method widely used in foreign work sites. LRFD (Load Resistance Factor Design) method is widely used in the fields in which the data accumulation is possible - such as deep foundations, and shallow foundations, etc. The limit state design in the retaining walls is insufficient in the country owing to difficulties applying load tests. The limit state design method for retaining wall structures are studied based upon the National Retaining wall Design Standard legislated in 2008 by Ministry of Land, Transport, and Maritime Affairs. In this paper several retaining walls were calculated according to LRFD design criteria analysis using the general program with limit state design method and the factor of safety for sliding and overturning. Comparing with their results, the Taylor's series simple reliability analysis was performed. In the analysis results of retaining wall section, safety factors calculated by LRFD were found to be lowered than those calculated in current WSD, and it is possibly judged to be economic design by changing wall dimensions. In the future, pre-assessment of the geotechnical data for ensuring the reliability and the studies including reinforced retaining walls with ground anchor are needed.

• Strategy21
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• s.37
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• pp.242-274
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• 2015

2015년 5월 수중발사 탄도미사일(SLBM) 발사시험을 통해 북한은 전 세계의 이목을 또 다시 집중시켰다. 북한은 2013년 제3차 핵실험을 감행한 이후 최근까지도 탄도미사일과 로켓 발사 등의 무력도발을 지속해 왔다. 이와 같은 북한의 무력도발은 한반도의 안정뿐만 아니라 미국 본토의 안보에도 매우 부정적인 영향을 미치고 있다. 지금까지 미국은 북한의 핵미사일 개발 저지를 위해 경제적 또는 군사적 방안들을 선별적으로 적용해 왔다. 그러나, 이러한 미국의 노력에도 불구하고 북한은 여전히 핵미사일을 개발하겠다는 꿈을 포기하지 않고 있는 것이 사실이다. 본 논문은 북한의 핵미사일 개발에 대한 미국의 대안적 전략(Alternative Strategy)을 제시하는데 그 목적이 있다. 필자는 대안적 전략 제시에 앞서 북한의 핵과 탄도미사일 개발현황을 내용(Contents)과 맥락(Context) 차원에서 분석하고 미 오바마 행정부의 대북전략을 비판적으로 검토하였다. 그리고 대안적 전략으로 동맹국과 함께 경제적(Sticky Power), 군사적(Sharp Power) 수단의 동기화(Synchronizing)를 통해 북한이 감당하기 힘든 전략적 환경을 조성(Shaping the Strategic Environment)하는 것이 '북한의 핵개발 포기' 라는 전략목표를 달성하는 방안 임을 강조하고 있다. 미국이 대안적 전략목표를 달성하기 위해서는 경제적 수단으로 ① 북한의 자금세탁 및 위조지폐 발행국 지정, ② 북한을 지원하는 모든 해외자산에 대한 제재조치, ③ 북한의 테러지원국 재지정, ④ 북한 제재를 위한 미국의 입법추진, ⑤ 대량살상무기 관련 금수품목의 확대를 적용함과 동시에 군사적 수단으로 ① 대량살상무기 비확산 활동 강화, ② 대탄도미사일 전략 개발 및 정보(ISR: Intelligence Surveillance and Reconnaissance) 공유, 맞춤형 억제전략(TDS: Tailored Deterrence Strategy)의 구체화 등을 통한 한·미 군사 억제방안의 강화, 그리고 ③ SM-3, THAAD(Terminal High Altitude Area Defense) 등 한·미·일 3자간 MD(Missile Defense)체제의 구축 등을 동기화하여 적용해야만 할 것이다. 미국의 대안적 전략은 ① 북한의 핵미사일 개발에 대한 중국의 협력방지, ② 한·중간 경제관계의 악화, ③ 한·일간의 역사적 긴장관계라는 위험요소를 내포하고 있는 것 또한 사실이다. 따라서 미국이 대안적 전략목표인 '북한의 비핵화' 달성을 위해서는 이와 같은 위험요소를 완화시키는 노력도 병행되어야 할 것이다. 끝으로, 미국은 북한의 김정은이 핵미사일 개발 포기라는 상이한 방향의 전략적 결정을 할 경우에 대비하여 한·미 연합훈련의 보류, 북한에 대한 경제제재조치 해제 등 북한과의 협상 가능성도 열어두고 이에 대해서도 철저하게 준비해 나가야 할 것이다.

• Journal of Animal Environmental Science
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• v.11 no.1
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• pp.35-44
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• 2005

The objectives of this study were to develop an image processing algorithm for finding the sick or the dead layers(SDL) rearing in the multi-tier layer battery, which is a core technology of remote monitoring systems for layers, and to test the performance of algorithm developed in the experimental poultry housing. Based on the literature study and experiment, the standing up of layer was set as a criterion for judging layers whether sick or dead. Then, by the criterion set, an algorithm was developed. The image processing algorithm developed was tested how well it could and SDL at the experimental poultry housing. Test results showed that its monitoring correctness of layers standing up in the cages having all healthy layers was $92\%$, and $96\%$ in the cages having SDL. Therefore, it would be concluded that the image processing algorithm developed in this study was well suited to the purpose of development.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.523-529
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• 2020

Power distribution management system is essential for the efficient management and operation of power distribution networks. The power distribution system is a system that manages the distribution network based on IT, and has been evolving along with the development of the power industry. The current power distribution system is designed to operate at a relatively low network transmission speed based on the independent operation of the main equipment. However, due to distributed resources such as photovoltaic or energy storage devices, which are rapidly increasing in popularity in recent years, the operation of future distribution environments is becoming more complex, and various information needs to be collected in real time. In this study, the requirements of the next-generation power distribution system were derived to overcome the limitations of the existing power distribution system, and based on this, the communication network system and performance requirements for the distribution system were defined. In order to verify the performance of the designed system, a software-based terminal device simulator was developed because it takes excessive time and cost to introduce a large-scale system such as a power distribution system. Using the simulator, a test environment similar to the actual operation was established, and the number of terminal devices was increased up to 1,000. The proposed system was shown to satisfy the requirements to support the functions of the next-generation power distribution system, recording less than 10 % of the communication network bandwidth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3C
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• pp.115-125
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• 2009

The preconsolidation pressure has been commonly determined by oedometer test. However, it can also be determined by insitu test, such as piezocone test with theoretical and(or) empirical correlations. Recently, Neural Network (NN) theory was applied and some models were proposed to estimate the preconsolidation pressure or OCR. It was already found that NN model can come over the site dependency and prediction accuracy is greatly improved when compared with present theoretical and empirical models. However, since the optimization process of synaptic weights of NN model is dependent on the initial synaptic weights, NN models which are trained with different initial weights can't avoid the variability on prediction result for new database even though they have same structure and use same transfer function. In this study, Committee Neural Network (CNN) model is proposed to improve the initial weight dependency of multi-layered neural network model on the prediction of preconsolidation pressure of soft clay from piezocone test result. Prediction results of CNN model are compared with those of conventional empirical and theoretical models and multi-layered neural network model, which has the optimized structure. It was found that even though the NN model has the optimized structure for given training data set, it still has the initial weight dependency, while the proposed CNN model can improve the initial weight dependency of the NN model and provide a consistent and precise inference result than existing NN models.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.133-160
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• 2018

$CO_2$ storage is a very important technology for reduction of greenhouse gas emissions and has been considered as almost the only viable and effective option for immediate large-scale $CO_2$ sequestration. Small-scale demonstration project for offshore $CO_2$ storage in the Pohang Basin is the transitional stage R&D program for technological preparation of large-scale $CO_2$ storage project in Korea. Through the extensive exploration research for prospective $CO_2$ storage sites, the offshore strata in the Pohang Basin was recommended for the storage formation of the small-scale demonstration project. The Pohang Offshore Storage Project launched at 2013, and has accomplished the technical demonstration and technological independence in a wide range of $CO_2$ storage technology, such as geophysical exploration, storage site characterization, storage design, offshore platform construction, injection-well drilling and completion, deployment of injection facility, operation of $CO_2$ injection, and $CO_2$ monitoring. The project successfully carried out $CO_2$ test injection in early 2017, and achieved its final goal for technical development and demonstration of $CO_2$ storage in Korea. The realization of $CO_2$ injection in this project is the measurable result and has been recorded as the first success in Korea. The Pohang Offshore Storage Project has a future plan for the continuous operation of $CO_2$ injection and completion of $CO_2$ monitoring system. The project has provided in-house technical and practical expertises, which will be a solid foundation for the commercial-scale $CO_2$ storage business in Korea. Additionally, the project will help to secure national technical competitiveness in growing international technology market for $CO_2$ storage.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.487-499
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• 2021

Purpose:The purpose of the paper is to review the problems of performance enhancement of safety certification standards and to suggest directions for improvement in order to rationalize safety certification standards for future industrial development and environmental changes. Method: The problems and limitations of the safety certification system are summarized through literature review and interview with manager, and the status of safety certification standards is classified into design standards, performance standards, and detailed standards, and the status analysis is performed. In addition, by synthesizing the results of the investigation and analysis, improvements are suggested to improve the performance of the safety certification standards. Result: Through the survey, the problems and limitations of safety certification could be grouped into six categories: government-led certification system operation, standardized certification standards, long time required to improve certification, poor certification standards preparation system, and lack of reflection of industry opinions. And, as a result of analyzing the certification standards by dividing them into performance and design standards, in the case of machinery, equipment, and protection devices, the design standards were high at 69.7% and 64.9%, whereas in the case of protective equipment, the performance standards were high at 61.1%. In order to improve the performance of safety certification standards centered on design standards, it is necessary to determine the possibility of performance enhancement of the certification standards and determine the feasibility of the inspection test method. In order to improve performance, it was reviewed that it was necessary to establish a systemic foundation and infrastructure, such as strengthening the Product Liability Act, systematizing market monitoring, etc., distributing certification test tasks, and participating in the preparation of certification standards by the private sector. Conclusion: Through this study, the problems and limitations of Korea's safety certification system were summarized and the necessity for performance improvement was reviewed. Performance improvement of safety certification standards is a matter that requires preparatory work, such as legislative revision and infrastructure construction, and requires mid-to-long-term promotion. In addition, rather than improving the overall safety certification standards, the performance requirements for each item subject to certification should be reviewed and promoted, and details should be specified through additional research.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.672-678
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• 2015

The types of hazardous and noxious substances (HNS) being transported by sea in Korea are at about 6,000, HNS transport volume accounts for 19% of total tonnage shipped in Korea, and the increase rate of seaborne HNS trade in Korea is 2.5 times higher than the average increase rate of the world seaborne HNS trade. Reflecting this trend, HNS spill incidents have been frequently reported in Korean waters, and there are increasing social demands to develop HNS management technology for the preparedness, response, post-treatment and restoration in relation to HNS spill incidents at sea. In this study, a risk-based HNS prioritization system was developed and an HNS risk database was built with evaluation indices such as sea transport volume, physicochemical properties, toxicities, persistency, and bioaccumulation. Risk scores for human health and marine environments were calculated by multiplying scores for toxicity and exposure. The top-20 substances in the list of HNS were tabulated, and Aniline was ranked first place, but it needs to be managed not by individuals but by HNS groups with similar score levels. Limitations were identified in obtaining data of chronic toxicity and marine ecotoxicity due to lack of testing data. It is necessary to study on marine ecotoxicological test in the near future. Moreover, the priority list of HNS is expected to be utilized in the development of HNS management technology and the relevant technologies, after the expert's review process and making up for the lack of test data in the current research results.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.839-845
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• 2006

A laser docking system provides a centimeter-level accuracy distance from jetty mounted laser sensors in order to help a vessel to approach to a pier. It is very accurate & useful, whereas there are too many considerable problems. Laser sensors of the laser docking system need to be correctly positioned and installed on a jetty to allow for full range of vessels to be berthed and to consider loading condition and tidal variations. Above all, the laser docking system is expensive and its service coverage is limited. In order to solve these problems, CDGPS positioning method using GPS satellites has been proposed. This paper presents that, through RHDOP simulation, the previous CDGPS positioning method using only GPS satellites is not able to provide the continuous service with centimeter-level positioning accuracy. And this paper proposes a pseudolite-augmented positioning method for vessel docking in order to solve the problem of the continuous service on the previous CDGPS positioning method. In this paper, pseudolite is used to aid in CDGPS positioning. This paper shows that the proposed method can provides the continuous service through comparison analysis of RHDOP simulation results between the GPS satellite constellation and the pseudolite-augmented GPS satellite constellation. Furthermore, it is shown that the proposed positioning method satisfies the positioning performance required for vessel automatic docking at a test bed designed for performance evaluation.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.72-81
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• 2014

As big data are one of main issues in the recent days, the interests on their technologies are also increasing. Among several technological bases, this study focuses on data visualization and R based on open source. In general, the term of data visualization can be summarized as the web technologies for constructing, manipulating and displaying various types of graphic objects in the interactive mode. R is an operating environment or a language for statistical data analysis from basic to advanced level. In this study, a web application with these technological aspects and components is newly implemented and exemplified with data visualization for geo-based open data provided by public organizations or government agencies. This application model does not need users' data building or proprietary software installation. Futhermore it is designed for users in the geo-spatial application field with less experiences and little knowledges about R. The results of data visualization by this application can support decision making process of web users accessible to this service. It is expected that the more practical and various applications with R-based geo-statistical analysis functions and complex operations linked to big data contribute to expanding the scope and the range of the geo-spatial application.