• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.175-187
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• 2013

Each participant in building construction project requires their own workspace to execute their activities. In this environment, inappropriate workspace planning in construction site causes workspace conflicts which result in a loss of productivity, safety hazard and poor-quality issues. Therefore, workspace should be regarded as one of the most important resources and constraints have to be managed at construction site. However, current construction planning techniques such as Gantt chart, network diagram and critical path method have proven to be insufficient to workspace planning. This paper contains formalized process for workspace planning in 4D BIM environment to prevent workspace related problems in construction project. The proposed process in this paper represents workspace occupation status for each activity and suitable solutions for identified workspace conflicts by integrating workspace attributes and activity execution plan. Based on the result of this study, project manager will be able to prevent probable workspace conflicts and negative effect on project performance by devising appropriate workspace plan during preconstruction phase.

• Journal of Distribution Science
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• v.11 no.1
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• pp.45-53
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• 2013

Purpose - The environment-friendly agricultural product market in Korea sees continual high growth. Recently, the Korean government has been actively fostering environment-friendly agriculture as an engine of future growth. Korean people have increasingly become more health-conscious and interested in food safety issues. Many distribution and retailing companies have responded with various promotional activities. However, most of these are not strategic and appear to have unsatisfactory outcomes. The main purpose of this paper is to suggest effective marketing strategies for environment-friendly agricultural products. To achieve this aim, the study empirically investigates the effects of consumer characteristics and trust on the purchase intention of environment-friendly agricultural products. Research design, data, methodology - Based on the theory of planned behavior, and previous studies related to the purchase intention and consumption of environment-friendly agricultural products, we set up five study hypotheses. These related to the demographic characteristics of consumers, purchase intention, and behavior of the products. We then set up a study model and four study hypotheses relating to health consciousness, environmental consciousness, consumer trust level, purchase intention, and behavior of the products. The data were collected using a questionnaire given to consumers living in Seoul and southern Geonggi Province. The final sample size is 403 and mean age is 44.3. SPSS 15.0 for Windows and Amos 7.0 were used as statistical analysis tools. Meaningful results were derived using frequency analysis, correlation analysis, a t-test, and structural equation modeling. Results - Empirical results of this research are as follows. (1) First, it is shown that consumers consider such attributes as intimacy and health to be important when they buy environment-friendly agricultural products. (2) We also found that consumers recognize the value of environment-friendly agricultural products as high, but their trust level as low. (3) Consumer groups consisting of married couples, with higher education, higher income, and higher age are shown to have a higher intention of buying environment-friendly agricultural products than any other consumer group. (4) It is estimated that the level of consumer trust positively affects the purchase intention of environment-friendly agricultural products. The path coefficient (.138) between consumer trust and purchase intention is statistically significant at the α = .05 level. (5). It is also estimated that environmental consciousness positively affects purchase intention. The path coefficient (.245) between environmental consciousness and purchase intention is statistically significant at the α = 0.05 level. The standardized path coefficients of consumer trust and environmental consciousness with purchase intention are .556 and .288 respectively. Therefore, consumer trust affects purchase intention more than environmental consciousness. (6) Finally, purchase intention is estimated to positively affect purchase behavior. Conclusions - Based upon empirical results, this research suggests that marketers of environment-friendly agricultural products should focus more on increasing consumer trust levels, emphasizing the training and education of employees. The government also should pay attention to a standardized certification system for environment-friendly agricultural products. Marketers of environment-friendly agricultural products should consider the consumer groups of married couples, with higher education, higher income, and higher age as a major target segment.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.93-101
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• 2005

The formation of slopes is unavoidable under the special circumstance of Korea where $7%$ of the whole area are composed of mountains and civil engineering projects such as road and site developments are increasing with industrial development and horizontal expansions of urban area. Stability of slopes is one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall is concentrated in summer season and the localized torrential downpour is getting more frequent recently. As a result of these circumstances, partial slope failures by debris flow of the high water content soils occur frequently in cut soil slopes. In this case of debris flow slope failure, slope declination method is selected fur the stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. For debris flow failure slopes, this study secured the safety of slopes by preventing the inflow of rainwater and scour using geosynthetics-reinforced embankment, and created nature-friendly slopes by planting trees on the slopes.

• Clean Technology
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• v.20 no.4
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• pp.398-405
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• 2014

In the treatment of spent high energetic materials, the issues such as environmental pollution, safety as well as working capacity should be carefully considered and well examined. In this regard, incineration has been recommended as one of the most promising processes for the disposal of such explosives. Due to the fact that high energetic materials encompass various types and their different characteristics, the technology development dealing with various materials is not an easy task. In this study, rigorous modeling and dynamic simulation was carried out to predict dynamic physico-chemical phenomena for research department explosive (RDX). Plug flow reactor was employed to describe the incinerator with 263 elementary reactions and 43 chemical species. Simulation results showed that safe operations can be achieved mainly by controlling the reactor temperature. At 1,200 K, only thermal decomposition (combustion) occurred, whereas increasing temperature to 1,300 K, caused the reaction rates to increase drastically, which led to ignition. The temperature further increased to 3,000 K which was the maximum temperature recorded for the entire process. Case studies for different operating temperatures were also executed and it was concluded that the modeling approach and simulation results will serve as a basis for the effective design and operation of RDX incinerator.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.281-288
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• 2014

As a gas explosion is the most fatal accident in shipbuilding and offshore plant industries, all safety critical elements on the topside of offshore platforms should retain their integrity against blast pressure. Even though many efforts have been devoted to develop blast-resistant design methods in the offshore engineering field, there still remain several issues needed to be carefully investigated. From a procedure for calculation of explosion design pressure, impulse of a design pressure model having completely positive side only is determined by the absolute area of each obtained transient pressure response through the CFD analysis. The negative pressure phase in a general gas explosion, however, is often quite considerable unlike gaseous detonation or TNT explosion. The main objective of this study is to thoroughly examine the effect of the negative pressure phase on structural behavior. A blast wall for specific FPSO topside is selected to analyze structural response under the blast pressure. Because the blast wall is considered an essential structure for blast-resistant design. Pressure time history data were obtained by explosion simulations using FLACS, and the nonlinear transient finite element analyses were performed using LS-DYNA.

• Journal of Science and Technology Studies
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• v.14 no.2
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• pp.1-48
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• 2014

Recently, governance of science and technology emerged as one of most important social problems and as a result it is crucial to understand it in science and technology studies. This article discusses three most important realms in science and technology goverance - research and development, regulation, and social movement - in the concrete Korean contexts. First of all, the Korean state has driven research and development and promoted its commercialization unlike other developed countries. Consequently, this nationalistic view on science disseminated to Korean public and it generated uniformity in research style and organization. Second, science and technology regulations embraced developed countries' policies, leading to its glocalization. As a result, technocratic old governance and new governance including precautionary principle and participatory democracy coexist. Third, the civil society has challenged expertise and state-driven science and technology governance and fueled social movements related to environment, safety, and health issues. The politics of knowledge created by citizens' voluntary participation and collaborative experts made it clear that science and technology should be no longer tool for economic development. In conclusion, we discuss characteristics of science and technology governance in Korea, giving various implication on current research and policy.

• Journal of the Korean Solar Energy Society
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• v.28 no.2
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• pp.64-69
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• 2008

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. There has been an argument that it may be a non-issue in practice because the probability of islanding is extremely low. However, there are three counter-arguments: First, the low probability of islanding is based on the assumption of 100% power matching between the PVPCS and the islanded local loads. In fact, an islanding can be easily formed even without 100% power matching (the power mismatch could be up to 30% if only traditional protections are used, e.g. under/over voltage/frequency). The 30% power-mismatch condition will drastically increase the islanding probability. Second, even with a larger power mismatch, the time for voltage or frequency to deviate sufficiently to cause a trip, plus the time required to execute a trip (particularly if conventional switchgear is required to operate), can easily be greater than the typical re-close time on the distribution circuit. Third, the low-probability argument is based on the study of PVPCS. Especially, if the output power of PVPCS equals to power consumption of local loads, it is very difficult for the PVPCS to sustain the voltage and frequency in an islanding. Unintentional islanding of PVPCS may result in power-quality issues, interference to grid-protection devices, equipment damage, and even personnel safety hazards. Therefore the verification of anti-islanding performance is strongly needed. In this paper, improved RPV method is proposed through considering power quality and anti-islanding capacity of grid-connected single-phase PVPCS in IEEE Std 1547 ("Standard for Interconnecting Distributed Resources to Electric Power Systems"). And the simulation results are verified.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.365-372
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• 2017

Squat exercise is one of the important free weight exercises that can safely and effectively expect the athletic performance by establishing the rationale. Therefore, it is necessary to study the side effects caused by incorrect exercise, scientific countermeasures and to develop a exercise estimation model. It is effective and accurate to use a variety of assistive devices to calibrate athletic posture. The issues of the structural analysis for designing a foot plate for squat exercise is to model the behavior by the dynamic behavior. It should be consider that the center of gravity of each segmented body is different when the maximum load is applied. It is applied to complete system design through simulation method with kinematic dynamic, ground reaction force and load analysis for the free weight exercise equipment, VR device, and safety foot plate. In this paper, the authors propose the design method for the vertical load distribution applied in the design of the foot plate used for the squat exercise mechanism, and based on these results, design make the more safe and reliable free weight exercise equipment system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.115-122
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• 2010

In this study, the removal of Cs and Tc from a simulated fission products (FP) solution which were co-dissolved with U during the oxidative-dissolution of spent fuel in a mixed carbonate solution of $(Na_2CO_3-NaHCO_3)-H_2O_2$ was investigated by using a selective precipitation method. As Cs and Tc might cause an unstable behavior due to the high decay heat emission of Cs as well as the fast migration of Tc when disposed of underground, it is one of the important issues to removal them in views of the increase of disposal safety. The precipitation of Cs and Re (as a surrogate for Tc) was examined by introducing sodium tetraphenylborate (NaTPB) and tetraphenylphosponium chloride (TPPCl), respectively. Precipitation of Cs by NaTPB and that of Re by TPPCl were completed within 5 minutes. Their precipitation rates were not influenced so much by the temperature and stirring speed even if they were increased by up to $50^{\circ}C$ and 1,000 rpm. However, the pH of the solution was found to have a great influence on the precipitation with NaTPB and TPPCl. Since Mo tends to co-precipitate with Re at a lower pH, especially, it was effective that a selective precipitation of Re by TPPCl was carried out at pH of above 9 without co-precipitation of Mo and Re. Over 99% of Cs was precipitated when the ratio of [NaTPB]/[Cs]>1 and more than 99% of Re, likewise, was precipitated when the ratio of [TPPCl]/[Re]>1.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.4
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• pp.155-162
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• 2013

Routing protocol in ad hoc mobile networking has been an active research area in recent years. However, the environments of ad hoc network tend to have vulnerable points from attacks, because ad hoc mobile network is a kind of wireless network without centralized authentication or fixed network infrastructure such as base stations. Also, existing routing protocols that are effective in a wired network become inapplicable in ad hoc mobile networks. To address these issues, several secure routing protocols have been proposed: SAODV and SRPTES. Even though our protocols are intensified security of networks than existing protocols, they can not deal fluidly with frequent changing of wireless environment. Moreover, demerits in energy efficiency are detected because they concentrated only safety routing. In this paper, we propose an energy efficient secure routing protocol for various ad hoc mobile environment. First of all, we provide that the nodes distribute security information to reliable nodes for secure routing. The nodes constitute tree-structured with around nodes for token escrow, this action will protect invasion of malicious node through hiding security information. Next, we propose multi-path routing based security level for protection from dropping attack of malicious node, then networks will prevent data from unexpected packet loss. As a result, this algorithm enhances packet delivery ratio in network environment which has some malicious nodes, and a life time of entire network is extended through consuming energy evenly.