• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.285-296
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• 1999

Preloading method is used to prevent the settling of a foundation and to increase the strength of ground by consolidation settlement in advance. But, the embankment used in preloading method brings large deformation and sliding failure in the soft ground. Recently, reinforcement method is often used in embankment in order to prevent sliding failure. But, until now, the research on the stability analysis considering both the rate of strength increase of clay by embankment load and increase of resistance force by the geosynthetics in the embankment body is not found. In this study, the stability analysis program(REAP) for embankment including these two points is developed. By this program(REAP), the stability analysis can be done about during the gradual increase of embankment and the stability counterplan can be established when the safety factor is lower than allowable safety factor of design. After calculating the position of sliding failure surface, the force of geosynthetics which is selected by either the effective tensile strength or tensile force caused by the displacement of soil mass in this position is applied to stability analysis. And the increase of resisting moment can be calculated by this force. Also, the construction period can be estimated and the time for the appropriate counterplan can be decided in order to maintain the stability of embankment. And then, safe and economical embankment design can be performed.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.674-683
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• 2010

The current study was performed to examine the agricultural suitability of the cultivated upland nearby abandoned mining areas in Korea using three different scientific risk assessment models of Korea, USA and UK. For this, three mining sites DM, MG and KS were selected among 687 abandoned mines through preliminary risk assessment. A wide range of parameters were obtained through analysis of both soil and crop samples from the selected areas for heavy metal concentration and questionnaires to the communities along with the selected mining sites. Heavy metal concentration in soil samples was lower than the values previously reported by the Ministry of Environment (ME, 2002). However, both As and Cd concentration in the soil samples exceeded the concern level for agricultural area of the Soil Environment Conservation Act. Judging from the contaminant criteria for the crops, only Zn level in pepper, soybean and corn from the mining area DM exceeded the criteria whereas As, Cd, $Cr^{6+}$, Cu, Hg, Ni, Pb did not exceed the criteria. It was demonstrated that there would be human health risk by Pb accumulated in crops from both mining areas MG and KS when estimated by the risk assessment models of Korea and USA. Against it, results of the risk assessment model of UK showed human health risk by Pb in the crops from all study areas.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.501-506
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• 2004

Microflora and contamination process of Saengshik products were investigated to ensure microbial safety of Saengshik. Food-borne pathogenic bacteria, such as Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens detected mainly from grains were not removed by washing with tap water and freeze-drying. Contaminations of food-borne pathogenic bacteria occurred through raw material powder processed at other factories and during actual product manufacturing process, because detection rates of final products were higher than those of raw materials. Concentration of food-borne pathogenic bacteria increased with advancing of process after first pulverization. Dusts of powder and powder attached to machine were good media for air-borne microorganisms and caused to increase of food-borne pathogenic bacteria during process. Improvement of manufacturing process and sanitary control of machines arc necessary to ensure microbial safety of Saengshik.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.367-378
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• 2006

A mobile phone has became as a payment tool in e-commerce and on-line banking areas. This trend of a payment system using various types of mobile devices is rapidly growing, especially in the Internet transaction and small-money payment. Hence, there will be a need to define its standard for secure and safe payment technology. In this thesis, we consider the service types of the current mobile payments and the authentication method, investigate the disadvantages, problems and their solutions for smart and secure payment. Also, we propose a novel authentication method which is easily adopted without modification and addition of the existed mobile hardware platform. Also, we present a simple implementation as a demonstration version. Based on virtual machine (VM) approach, the proposed model is to use a pseudo-random number which is confirmed by the VM in a user's mobile phone and then is sent to the authentication site. This is more secure and safe rather than use of a random number received by the previous SMS. For this payment operation, a user should register the serial number at the first step after downloading the VM software, by which can prevent the illegal payment use by a mobile copy-phone. Compared with the previous SMS approach, the proposed method can reduce the amount of packet size to 30% as well as the time. Therefore, the VM-based method is superior to the previous approaches in the viewpoint of security, packet size and transaction time.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.673-683
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• 2015

The existing flood protection in rivers has shown the limitation due to the urbanization around rivers and the abnormal climate. Thus, the demand for the constructions of side-weir detention basin are being increased as a part of integrated watershed flood protection plan. It is necessary to estimate the quantitative flood-control effect for including the side-weir detention basin in flood-control measures. For the determination, it is required to reduce the uncertainty of the design factors which can affect the flood-control effect of side-weir detention basin. Among the factors, however, the water level in river always contains uncertainty. Therefore, the design method considering the uncertainty is required. For the reasons, the design method considering uncertainty of the water level in river is suggested in this study with using the length of side-weir which is relatively easy-determinable by designers. Therefore, it is examined how the variation of the length of side-weir can affect the flood-control effect, using HEC-RAS, and then the method to determine the side-weir length considering the uncertainty of the water level in river through results from analyses. Since the uncertainty of the water level in river can be taken into account in the suggested design method, it is evaluated that the design method is more effective to suggest the flood-control effect of the side-weir type detention basin with higher safety side.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.173-173
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• 2011

최근 기후변화로 인한 기상재해 중 건조와 관련하여 인플루엔자, 호흡기질환 등과 같은 질병과 산불발생빈도의 증가로 인해 건강 및 재산상의 피해가 증가하고 있다. 특히, 한반도의 주택지역은 산림지역과 근접하여 산불 발생시 그 피해와 복구비용이 막대한 것으로 나타났다. 뿐만 아니라 향후 지구온난화가 가속화 될 경우 건조와 관련한 환자와 산불로 인한 피해가 증가할 것으로 예상되므로, 이에 대한 사전방재계획 및 복구계획 등이 필요하다. 이와 같은 건조현상 등의 자연재해에 대한 방재계획이 효과적으로 운영되기 위해서는 방재 정보를 인지하고 실천하는 개인의 적극적인 활용이 필요하다. 특히, 개인의 생활에 영향을 미치는 피해는 정부적인 대책보다 개인이 스스로 인지하여 대비함으로써 감소시킬 수 있기 때문에 재해에 대한 개인의 인지정도는 대책마련에 있어 중요한 요인이 된다. 이에 따라, 본 연구에서는 건조로 인한 질병 및 산불 발생 등 기상재해 증가에 대한 사전방재계획의 효과적인 운영을 위하여 설문조사분석을 통한 일반인의 건조특보 인지도 및 활용도 분석을 실시하였다. 또한, 기후가 변화함에 따라 더운 낮과 밤의 증가로 건조현상뿐만 아니라 폭염의 발생빈도도 증가할 것으로 예상되고 있다. 이와 관련하여 기후변화 적응측면에서 국민들의 건조특보 및 폭염특보와 관련한 정보 습득이 잘 이루어지고 있는지를 파악하고자 한다. 이를 위해, 선행연구에서 대학생의 주된 폭염특보 관련 정보습득경로가 TV와 인터넷인 점을 참고하여, 기상청에서 제공하는 건조특보와 폭염특보 발표일수와 TV, 인터넷의 대중매체를 통한 보도회수를 비교 분석하였다. 본 연구를 통해 대학생집단과, 10대, 20대의 저연령층의 인지도가 상대적으로 낮은 것으로 파악되었으며, 이는 대중 매체를 통한 건조특보와 관련한 정보전달의 부족으로 나타났다. 폭염특보와 관련한 언론보도는 기상전달뿐만 아니라, 폭염의 위험성, 폭염으로 인한 피해상황, 폭염특보제 홍보, 폭염과 관련한 대비책 등 다양한 내용으로 기재되었다. 반면에, 건조특보의 경우에는 대부분이 단순 기상전달로 폭염특보에 비해 보도의 다양성이 결여되어 있었다. 차후 대중매체를 통한 이용자들의 접근성을 증대시키기 위해서 신속하고 정확한 정보전달이 필요하다. 산불 및 화재예방과 관련하여 기상청의 정확한 기상정보 제공과 사전방재계획 수립에 대한 필요성을 직업별, 연령별로 구성된 각 집단의 50%이상이 느끼는 것으로 나타났다. 이에 따라, 기상정보 전달의 핵심인 기상청을 중심으로 온라인/오프라인 상의 기초교육부터 체계적인 사전방재계획 및 안전교육 프로그램 마련이 필요하다.

• Convergence Security Journal
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• v.14 no.4
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• pp.73-84
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• 2014

As the society turns into more of an information an technology centric society, the importance of information security is being increased these days. Recently, as the number of leaking accidents of personal information and valuable industrial technology is on the rise, every field of industry endeavors to come up with a security solution. In particular, since defense industry is a field where it establishes national defense power that is essential of national security, it requires higher standards of security solutions than any other ordinary fields of industry. According to Defense Industry Security Work Instructions, defense industry firms from security organizations and employ a security worker corresponding to the firm's scale and conditions. In an environment where essential information and technology are stored and managed in information and communication system or storing media, the duty and role of IT security workers are crucial. However, there is a shortage of systematic analysis on the work of IT security workers and development of curriculum to enhance their professionalism. Thus DACUM process, a job analysis technique, was used to identify IT Security workers' duties and responsibilities and verify the validity and credibility of the deducted results from the survey. The findings of this study will help in development of IT security duty in defense industry and can be used as baseline data for the development of curriculum and amendments of related regulations.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1706-1710
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• 2007

하천의 교각주위에는 국부세굴현상과 이에 따른 퇴적현상이 나타난다. 특히 교각주위에서의 국부세굴특성은 교량의 안전성과 관련하여 중요한 문제가 되므로 세굴의 크기를 감소하기 위한 대책이 필요하다. 교각주위에서의 국부세굴현상은 교각부 인근에 형성되는 말발굽형 와류가 중요한 역할을 하고 있는 것으로 알려져 있다. 따라서 교각주위에서의 수류변화를 적절히 제어함으로서 세굴특성을 감소하고자 하는 연구가 행해져 오고 있으며, 교각에 원환(collars)을 설치하거나 조도를 증가시킴으로 세굴감소 대책을 제안하고 있다(Zarrati et al, 2006). 본 연구에서는 교각주위에서의 세굴을 감소하기 위해 원주교각의 표면을 파상형(riblet type)으로 하였으며, 파상형교각의 기본개념은 원주교각 전면에 나타나는 하강류를 파상형 원주내로 흡수하여 세굴작용을 감소시키고자 하는 것이다. 이같은 형식은 원주형 교각에 원환을 설치하는 방법이 대표적이며 하상과 교각사이 경계부에 수평방향의 단일 파형(single riblet type)을 설치한 Sato et al(1993)의 연구가 있다. 이들의 결과에 의하면 원형교각과 비교하여 초기 세굴감소 효과가 있음을 확인하였으나 시간경과에 따라 세굴이 점차 증가하고 있는 바 그 원인으로서 세굴이 진행되면서 하상면과 단일 파형과의 간격이 확대하여 단일파형내로의 흐름흡수 효과가 감소하기 때문으로 보고되었다. 따라서 여기서는 이같은 문제를 해결하기 위해 다단의 오목 및 볼록 파상형(concave/convex riblet type) 원주교각에 대한 국부세굴 특성을 검토하였다. 또한 원주형의 교각에서는 단일원주보다는 원주군으로 설치되는 경우가 대부분이며 이때 교각의 직경(D)에 대한 교각 사이 간격$(L_d)$의 비$(L_d/D)$에 따른 전면교각에서의 수류변화의 영향이 후면교각에 작용하여 상호 복합적인 흐름 및 세굴특성을 나타내므로 이와 같은 복렬형 원주군의 세굴특성을 파상형 원주교각에 적용하여 국부세굴의 크기 변화를 해석하였다. 따라서, 교각주위에서의 수류특성 및 세굴의 변동은 원주군 및 교각파상의 크기와 간격 등과 같은 구조물의 배열조건과 Froude 수, 수심 등의 수리학적 조건에 따라 달라지므로 이의 조건을 체계적으로 변화시켜 가면서 교각주위에서의 국부세굴 및 세굴 감소특성을 검토하였다. 실험결과 오목 및 볼록 파상형 원주 주위에서의 세굴크기는 원형원주와 비교하여 전체적으로 감소하는 것으로 확인되었으며 특히 오목형 $B/\acute{h}=3$에서는 세굴경감효과가 탁월하여 70%이상 감소하는 것으로 확인되었으나 볼록형 $B/\acute{h}=5$에서는 세굴촉진특성이 나타나고 있는 것으로 나타났다. 따라서, 파상형 원주에서는 하강류나 와류를 파상형의 내부로 유도하여 세굴의 크기를 조절할 수 있는 최적의 파상이 존재하고 있는 것으로 예측되었다.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.704-711
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• 2010

Lignocellulose ($2^{nd}$ generation) is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of agriculture residuals and nonedible crops biomass, e.q., rice straw and miscanthus sinensis, because of their several superior aspects as agriculture residual and nonedible crops biomass; low lignin, high contents of carbohydrates. In this article, as the basic study of AP(Ammonia Percolation), the properties and the optium conditions of process were established, and then the overall efficiency of AP was investigated. The important independent variables for AP process were selected as ammonia concentration, reaction temperature, and reaction time. The percolation condition for maximizing the content of cellulose, the enzymatic digestibility, and the lignin removal was optimized using RSM(Response Surface Methodology). The determined optimum condition is ammonia concentration; 11.27%, reaction temperature; $157.75^{\circ}C$, and reaction time; 10.01 min. The satisfying results were obtained under this optimized condition, that is, the results are as follows: cellulose content(relative); 39.98%, lignin content(relative); 8.01%, and enzymatic digestibility; 85.89%.

• Korean Security Journal
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• no.56
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• pp.83-105
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• 2018

Special security guards play the role to safely operate and manage nuclear power plants from unintended internal and external threats. Physical fitness management of special security guards is one of the most important factors for improving and maintaining the level of physical protection. Thus, the purpose of this study is to analyze the physical fitness factor and physical fitness level required for mission accomplishment through job analysis of special security guards. The special security guards of Nuclear Power Plant in Korea were performing 7 jobs, 26 duties, 159 tasks. In order to accomplish theses tasks, the following physical fitness were required: muscle strength and muscle endurance of the hand, upper limb, lower limb and core, quickness, agility and Cardio function. The duties that require a lot of physical fitness were in the order of conducting arrest and self-defense, conducting unarmed defensive tactics, demonstrating proficiency with semiautomatic rifle, using protective equipment, performing emergency plan and defensive strategy, etc. The results of this study are expected to provide basic data necessary for establishing guidelines for fitness qualification and training of special security guards in the future and contribute to enhancement of physical protection of nuclear power plants.