• Journal of the Korea Concrete Institute
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• 제29권3호
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• pp.237-248
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• 2017

Frequent terror or military attack by explosion, impact, fire accidents have occurred recently. These attacks and incidents raised public concerns and anxiety of potential terrorist attacks on important infrastructures. However, structural behavioral researches on prestressed concrete (PSC) infrastructures such as Prestressed Concrete Containment Vessel (PCCV) and Liquefied Natural Gas (LNG) storage tanks under extreme loading are significantly lacking at this time. Also, researches on possible secondary fire scenarios after terror and bomb explosion has not been performed yet. Therefore, a study on PSC structural behavior from an blast-induced fire scenario was undertaken. To evaluate the blast-fire combined resistance capacity and its protective performance of bi-directional unbonded PSC member, blast-fire tests were carried out on $1,400mm{\times}1,000mm{\times}300mm$ PSC specimens. Blast loading tests were performed by the detonation of 25 kg ANFO explosive charge at 1.0 m standoff distance. Also, fire and blast-fire combined loading were tested using RABT fire loading curve. The test results are discussed in detail in the paper. The results can be used as basic research references for related research areas, which include protective design simulation under blast-fire combined loading.

• Journal of Internet Computing and Services
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• 제19권5호
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• pp.21-31
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• 2018

Cyber penetration attacks can not only damage cyber space but can attack entire infrastructure such as electricity, gas, water, and nuclear power, which can cause enormous damage to the lives of the people. Also, cyber space has already been defined as the fifth battlefield, and strategic responses are very important. Most of recent cyber attacks are caused by malicious code, and since the number is more than 1.6 million per day, automated analysis technology to cope with a large amount of malicious code is very important. However, it is difficult to deal with malicious code encryption, obfuscation and packing, and the dynamic analysis technique is not limited to the performance requirements of dynamic analysis but also to the virtual There is a limit in coping with environment avoiding technology. In this paper, we propose a machine learning based malicious code analysis technique which improve the weakness of the detection performance of existing analysis technology while maintaining the light and high-speed analysis performance applicable to commercial endpoints. The results of this study show that 99.13% accuracy, 99.26% precision and 99.09% recall analysis performance of 71,000 normal file and malicious code in commercial environment and analysis time in PC environment can be analyzed more than 5 per second, and it can be operated independently in the endpoint environment and it is considered that it works in complementary form in operation in conjunction with existing antivirus technology and static and dynamic analysis technology. It is also expected to be used as a core element of EDR technology and malware variant analysis.

• Journal of Korean Society of Forest Science
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• 제98권6호
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• pp.669-675
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• 2009

The purpose of this study was to examine the influence of land use change in the forest catchment on sedimentation rate at the outlets of rivers in Kushiro Mire that have been impacted by forest clearing, agricultural activity and river regulation. We analysed Caesium-137(Cs-137) concentration in sediment cores, and we estimated sedimentation rates and Cs-137 inventories over the last 50 years. Cs-137 from atomic bomb testing first entered the environment in 1954 which provides easily identifiable chronological markers in the sediment. Because Cs-137 is strongly absorbed into sediment particles, its redistribution occurs in association with sedimentary particles. Since the 1950s, the forest catchment areas draining into the mire have been developed intensively from forest areas to agricultural lands. The sediment accumulations at the outlets of rivers after 1954 ranged from 36 to 148 cm. The Cs-137 inventory is significantly greater than the reference sites which reflected natural accumulation conditions because sediment containing Cs-137 was carried from catchments into the outlets of the rivers. In addition, the Cs-137 inventory was correlated with the sedimentation rate. However, the Cs-137 inventories in Kuchoro and Kushiro river profiles were slowly increased with the sedimentation rates. This is because the sediment originating from scoured areas such as streambeds and banks contains a low level of Cs-137 concentration.

• Journal of the Korea Organic Resources Recycling Association
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• 제26권3호
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• pp.55-61
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• 2018

This study evaluated if the selected samples meets the Solid Refuse Fuel quality criteria in Korea. Biomass and plastic wastes generated in D City were mixed in diverse ratio. When the biomass content was about 40%, the moisture content was close to the SRF criteria and was measured to be 9.8%. The ash contents were analyzed up to 4.19%, and the lower calorific values based on Steuer, Dulong Equation and Bomb Calorimeter were at least 4,851, 4,181 and 3,847 kcal/kg, respectively. As a result of the elemental analysis, sulfur and chloride content were measured up to 0.05%. Those values satisfied the SRF criteria. Also, heavy metals(Hg, Cd, Pb, As) were analyzed to be below the SRF criteria. This makes it possible to use efficiently the wood byproducts abandoned in the woods, and the physical properties of wood being weak to moisture can be supplemented with plastics. Consequently, if plastic and biomass were well mixed and made into SRF, it would overcome the problem of shortening the life span of incineration facilities due to the high temperature of plastic wastes in the incinerator.

• Journal of the Korean Society of Food Science and Nutrition
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• 제22권5호
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• pp.531-538
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• 1993

A 4-week energy balance study was conducted to estimate the energy expenditure (EE) of 16 primary school age boys and girls, 8 to 12 year age, by measurement of energy intakes and changes in body energy (BE) content (intake / balance technique), keeping their normal living pattern and eating behavior. Gross energy intake (GE) and fecal energy (FE) loss was measured by bomb calorimetry. Urinary energy (UE) loss was calculated from nitrogen excreted. Fat mass (FM) was determined from body density estimated from skinfold thickness. Mean constitutional ratio of carbohydrate, protein and fat for the total energy intake was 10.1 $\pm$1.8%, 12.2$\pm$0.1% and 17.1$\pm$2.0% for the boys and 74.0$\pm$1.7%, 10.7$\pm$0.3% and 15.3$\pm$0.5% for the girls, respectively. Fecal energy loss was 5.1% and 4.5% proportion of the gross energy intake for the boys and girls, respectively. Mean daily metabolizable energy estimated by subtract feral and urinary energy loss was 1862$\pm$15kcal for the boys and 1627$\pm$20kcal for the girls. Total body energy change estimated from body composition change over 28 days was increased 1524$\pm$539kcal for the boys and 3622$\pm$718kcal for the girls. Mean daily energy expenditure was 1812$\pm$37kcal(52 $\pm$2kcal/kg of body weight) for the boys and 1487$\pm$25kca1 (52$\pm$2kcal/kg of body weight) for the girls.

• Korean Security Journal
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• 제18호
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• pp.1-20
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• 2009

Nowadays most nations around the world including Korea have experienced absolute shortages of available urban space. To solve various problems of the city, each nation constantly tends to extend the underground space. However there is a serious problem in making use of the underground space. Especially new terrorism coming into existence after 9.11 terror turns into the so-called ‘soft target’ which has something to do with public transportation facilities available to most people. Good examples are like these: poisonous gas attacks in Tokyo subway in 1995, Daegu subway station fire in 2003, serial bomb blast of London subway in 2005. In spite of being a concern on incidents related to the underground space it is inevitable to utilize the underground space and the tendency is growing. But Korea lags badly behind in foreign countries in this field and so seeking measures is urgently needed. Therefore the aim of this study is to note visible damages stemmed from the domestic and foreign underground space and propose more effective and adequate measures. Safety measures of terrorism are associated to minimize damage out of terrorism and they are as follows. In the first place, preparing protective equipment for saving a life from fire attacks and poisonous gas is needed urgently. In the second place, counterpart management on the spot and systematic security training should be established in order to minimize injury. In the third place, fire escapes must be provided for a rapid evacuation of potential unspecified individuals. In the fourth place, building up a network of related institutions is required for a systematic omnidirectional counterpart. Finally the Korean government ought to take fast and appropriate actions for the injured and bereaved family of the terror incident.

• Journal of the Society of Disaster Information
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• 제7권4호
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• pp.273-285
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• 2011

This research present actual conditions on realization about safety of observable individual and country, terror countermeasure from danger of terrorism which special guards have. To achieve these purposes, 400 special guards were sampled using the convenience sampling method and collected data through questionnaire from self-administration method. the collected data are in statistics of p<.05 levels. As the result, we drew following conclusions. Special guards thought that terror might occur most in 'aircraft, rapid-transit railway, subway, and bus'. It was no difference in society demography(p>.05). In type of terror, 'bomb terror' seemed to happen most, and they recognized that biochemistry terror and factor terror, and hostage terror may happen in society demography. Purpose of terror was thought that 'political purpose' may be the biggest, and 'ideological purpose' and 'social purpose' joined the remainder. According to society demography, woman's realization about terror was higher than man in two low variables. According to age, image of terror was high in 40 more than 20. According to educational background, university graduate were higher than a high-school diploma in two low variables. According to place of work, metropolis was higher than small and medium-sized city.

• Journal of the Society of Disaster Information
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• 제8권3호
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• pp.287-296
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• 2012

This study is analysis of the existing domestic terrorism factors and suggest countermeasures for political leadership that can occur to the precautionary terror occasion of the presidential election approached 100 days in the future. Political terror caused mainly achieved peak of Ideology or social conflict by Politically alienated class. Common cause is most likely to occur when the party or the government want to attack a target or can not stand disadvantaged and lose that I suppert the party or the government. 21st century political terror is occurred with Misfits of complaints expressed or social conflict more frequency than attack used random people, new weqpon and bomb. It is interpreted that issued as a drastic measure from individual complaint because of increased polarization of wealth by separate into group and fallen law and order but also we are not familiar with the political compromises. Personal safety escort mission is essential condition of political activity that Absolute personal protection and to come up with a large number of voters for best result. Thus security guard ought to professional security activity depend on gathered situation, location and regional feature for perfect protection service.

• Journal of the Korean Chemical Society
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• 제44권6호
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• pp.526-532
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• 2000

Cation exchange separation and inductively coupled plasma atomic emission spectrometric(ICP-AES) determination of ruthenium in HCl solutions were studied to quantitatively determine ruthenium in spent nuclear fuels. Ruthenium-bearing samples were dissolved with the mixed acid solution(9 : 1 mole ratio, HCl-HNO$_3$) using an acid digestion bomb. Based on the absorption spectra and ion exchange behaviour of ruthenium in hydrochloric acid media, its possible chemical species were discussed. On a cation exchange column (0.7 ${\times}$ 8.0 cm) packed with AG 50W ${\times}$ 8(100~200 mesh) and equilibrated with 0.5 M HCl, ruthenium was eluated with 0.5 M HCl while uranium was retained on the column. The established separation method was applied to a simulated spent nuclear fuel and resulted in the recovery of 98.5% with a relative standard deviation of 0.7%.

• Journal of the Korea Concrete Institute
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• 제28권6호
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• pp.685-693
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• 2016

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridionally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.