• The Journal of Engineering Geology
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• v.30 no.4
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• pp.589-602
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• 2020

As can be seen in many earthquakes, liquefaction causes differential settlement, which sometimes produces serious damages such as building destruction and ground subsidence. There are many possible active faults near the Busan city and the Yangsan, Dongrae, and Ilgwang faults among them pass through the city. The Busan city is also located within the influence of recent earthquakes, which occurred in the Gyeongju, Pohang, and Kumamoto (Japan). Along the wide fault valleys in the city, the Quaternary unconsolidated alluvial sediments are thickly accumulated, and the reclaimed lands with beach sediments are widely distributed in the coastal area. A large earthquake near or in the Busan city is thus expected to cause major damage due to liquefaction in urban areas. This study conducted an assessment of the liquefaction hazard according to seismic recurrence intervals across the Busan city. As a result, although there are slight differences in degree depending on seismic recurrence intervals, it is predicted that the liquefaction potential is very high in the areas of the Nakdonggang Estuary, Busan Bay, Suyeong Bay, and Songjeong Station. In addition, it is shown that the shorter the seismic recurrence interval, the greater difference the liquefaction potential depending on site periods.

• Journal of Construction Engineering and Project Management
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• v.1 no.2
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• pp.37-42
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• 2011

The key role in safety management is to identify any possible hazard before it occurs by identifying any possible risk factors which are critical to risk assessment. It is well known that falsework (temporary facilities) in construction projects is fundamentally important. This planning/assessment process is considered to be tedious and requires a lot of attention due to the following reasons: firstly, the installation and dismantling of those facilities are one of the high risk activities in the job sites. Secondly, temporary facilities are generally not clearly delineated on the building drawings. Therefore, it is our strong belief that safety tools have to be simple and convenient enough for the jobsite people to manage them easily and be flexible for any occasions to be occurred at various degrees. In order to develop a safety identification system of temporary facilities, this research utilizes the BIM technology in retrieving important information by importing data from BIM models and use it in the safety planning stage.

• Clean Technology
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• v.22 no.1
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• pp.1-8
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• 2016

Rapid growth in nanotechnology promise novel benefits through the exploitation of their unique industrial applications. However, as increasing of production amount of nanomaterials, their unintentional exposure to the environment has been caused. Therefore, there is a need for effective management of nanowaste to the sustainable nanotechnology. One possible endpoint at the environmental exposure scenario for nanowaste treatment is incineration. Although a few study on the incineration of nanomaterials was reported, pioneering researchers found that although it is possible to incinerate nanowaste without releasing nanoparticles into the atmosphere, the residues (bottom ash or slag) with nanomaterials eventually end up in landfills. Though there are still many questions to understand the fate of nanomaterials in incinerator, firstly we have to study whether nanowaste treatment via incineration is safe to human and environment.

• Journal of the Ergonomics Society of Korea
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• v.10 no.2
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• pp.51-55
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• 1991

Since slipping has been identified as a major hazard, it is important to understand the mechanism of a slip. Many researches, based on biomechanical studies, had been attempted to do that. Thowever, the correlation between the mechanism of a slip and psychophysical behaviors of people had rarely been verified. For example, the existence of small slips in a forward direction, which do not normally perceived by human subjects, has been established by several experimenters. However, the term "microslips are not perceived by the walkers[4]." has not been examined precisely by any experiments. The objective of this study is, using a Signal Detection Theory (SDT), to define a microslip and slip more quqntitatively with the biomechanical measurement of slip distance. The results showed that, the slip distance around the 3 centimeters, there was a obvious change in the accident detectability of the subject. The conclusion is that it is possible to identify the boundary of a microslip and slip around the 3 centermeters of slip distance.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.636-639
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• 2007

The frequently flooded area has been known as very vulnerable area. This area has nature disasters such as typhoon, storm and flood almost every year. The purpose of this study is to develop a management system for frequently flooded area by Web based. So this system is possible to disaster management which irrespective of time and place. Through this system, general user can easily retrieve status information and obtain that in visual way such as maps. graph, and texts if they have only certain web browsers.

• KCI Concrete Journal
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• v.13 no.2
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• pp.26-32
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• 2001

A simple expected damage cost model is developed and a systematic approach to evaluate the economic effects of seismic hazards to reinforced concrete structures is presented. An expected damage cost function during a specific lifetime is modeled by a Poisson's process with uniform continuous cash flow assumption. It is possible that the proposed method can decouple the damage cost effect from random earthquake events. Thus, expected damage cost function can be formulated as a combination of three independent terms; a present worth factor of Poisson's process, a damage cost interpolation function and a mean occurrence rate of earthquake intensity. The validity of the proposed method is demonstrated by a comparative study of LCC evaluations with the previous study.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.609-614
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• 2005

Gas hydrates are ice-l ike sol id compounds that are composed of water and natural gas. All common gas hydrates belong to the three crystal structures that are composed of five polyhedral cavities formed by hydrogen bonded water molecules and stable in specific high pressure and low temperature conditions. Gas hydrates contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions, and they may therefore represent a potential energy resource in the future. United States and Japan perform the national R&D programs for the commercial production of gas hydrates in 2010's. The study on gas hydrates are also important for exploration and development of natural gas in the regions where gas hydrates are accumulated and could be formed. Although their global abundance is debated, they play an important role in global climate change since methane is a 50 times more effect ive greenhouse gas than carbon dioxide. Natural gas hydrates also form a possible natural hazard if rapidly dissociated and can cause slides and slumps and in the marine environment associated tsunamis.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.193-200
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• 2000

Modelling the dependence via random effects in censored multivariate survival data has recently received considerable attention in the biomedical literature. The random effects models model not only the conditional survival times but also the conditional hazard rate. Systematic likelihood inference for the models with random effects is possible using Lee and Nelder's (1996) hierarchical-likelihood (h-likelihood). The purpose of this presentation is to introduce Ha et al.'s (2000a,b) inferential methods for the random effects models via the h-likelihood, which provide a conceptually simple, numerically efficient and reliable inferential procedures.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.2
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• pp.41-51
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• 1999

In sole-source procurement contraction for government goods and services, the buyer (government) needs to derive the optimal actions from the contractor so the buyer can obtain the maximum utility and the contractor, or single-source supplier, is guaranteed the equivalent of a minimum level of profit. Under the assumption of risk-neutrality for both the buyer and the contractor and the buyer's unobservability of the contractor's action, it is necessary for the buyer to design a (mathematical) model to achieve the above objective. This paper considers the mathematical formulation in which two problems - moral hazard and adverse selection - are present simultaneously; furthermore, from the formulation, a GAMS (General Algebraic Modeling System) program is used for a possible buyer to obtain the optimal actions.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.39-44
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• 2018

Dust explosions are occurring in a variety of industries. A dust explosion caused by a specific energy generates huge amount of energy in the ignition and releases decomposition gas. Damages can be increased since this released decomposition gas can cause second and subsequent explosions. In this study, the goal was to obtain practical information on what could affect the explosion by comparing the characteristics of two kinds of dusts with completely different chemical properties. Three kinds of dusts were measured and evaluated for explosion pressure, dust explosion index, explosion limit and minimum ignition energy. It is possible to grasp the characteristics of each dust and use it as useful accident prevention data in the production of raw material powder.