• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.473-479
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• 2008

Environment problem has been arising in many countries. Especially, soil erosion has been deemed as one of the biggest issues because sediment causes muddy water and pollutants, such as agricultural chemicals, flow in the stream with this sediment. Many studies, regarding soil loss and non-point source pollution from watershed, has been performed while serious problem has been known. Soil loss occurred in most agricultural area by rainfall and runoff. It makes hydraulic structure unstable, causes environmental economical problems because muddy water destroys ecosystem and causes intake water deterioration. As revealing serious effects of muddy water by sediment, many researches have been doing with various methods. Hydraulic structures establishments such as soil erosion control dams and grit chamber are common. Vegetative filter strip is investigated in this study because vegetative filter strip is designed for reducing sediment from upland areas of the watershed, and it has many functions, not only sediment reduction but also runoff water quality improvement and wildlife habitat. With these positive functions of the vegetative filter strip, the study about vegetative filter strip has been increasing for reducing sediment because it is more effective than hydraulic structures from an environmental perspective. But the sediment trapping efficiency by vegetative filter strip, needs to be investigated and designed first. Therefore the model, VFSMOD-W, was used in this study as it can estimate sediment trapping efficiency of vegetative filter strip under various field, vegetation, weather condition. Sensitive factors to sediment trapping efficiency are studied with VFSMOD-W, and sediment trapping efficiency equation has been derived using two most sensitive factors. It is thought that the equation suggested in this study can be used in Soil and Water Assessment Tool (SWAT), to overcome the limit of SWAT filter strip module, which is based solely on filter strip width.

• Industry Promotion Research
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• v.8 no.3
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• pp.95-109
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• 2023

The purpose of this paper is to empirically grasp the influence on self-efficacy and depression and the relationship between variables, focusing on middle-aged women in their 40s and 50s who are psychologically and socially vulnerable. Through this, it was intended to explore the psychological problems of highly educated careerinterrupted women from a personal perspective and further derive implications for the development of policies and services for socially highly educated career-interrupted women. The relationship between variables was analyzed through a survey based on measurement tools structured by variables of Saju factors, self-efficacy, and depression, and the effect of the sub-dimensional characteristics of Saju structure on self-efficacy, and the resulting level of depression were verified through structural equation model analysis. Bigeop, Jaeseong, and Kwanseong have been found to have a positive and direct effect on self-efficacy and negative direct effect on depression, eventually increasing self-efficacy and lowering depression. It was found that Siksang had a positive (+) relationship with depression and a negative (-) relationship with self-efficacy, but Inseong did not directly affect self-efficacy and depression. In addition, the indirect effects between variables and the effects between self-efficacy and depression were identified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.479-485
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• 2006

The double gate(DG) MOSFET is a promising candidate to further extend the CMOS scaling and provide better control of short channel effect(SCE). DGMOSFETs, having ultra thin undoped Si channel for SCEs control, ale being validated for sub-20nm scaling. A novel analytical transport model for the subthreshold mode of DGMOSFETs is proposed in this paper. The model enables analysis of short channel effect such as the subthreshold swing(SS), the threshold voltage roil-off$({\Delta}V_{th})$ and the drain induced barrier lowering(DIBL). The proposed model includes the effects of thermionic emission and quantum tunneling of carriers through the source-drain barrier. An approximative solution of the 2D Poisson equation is used for the distribution of electric potential, and Wentzel-Kramers-Brillouin approximation is used for the tunneling probability. The new model is used to investigate the subthreshold characteristics of a double gate MOSFET having the gate length in the nanometer range $(5-20{\sim}nm)$ with ultra thin gate oxide and channel thickness. The model is verified by comparing the subthreshold swing and the threshold voltage roll-off with 2D numerical simulations. The proposed model is used to design contours for gate length, channel thickness, and gate oxide thickness.

• The Journal of Industrial Distribution & Business
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• v.9 no.4
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• pp.63-72
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• 2018

Purpose - The purpose of this paper is to investigate the effects of online game properties, social interaction, and player satisfaction on intention to online games in Chinese gamers. Research design, data, and methodology - This study is an empirical analysis assuming that properties of online games, social interaction and satisfaction will induce Chinese gamers' intention to play online games. We set the relationship between the six variables as follows. First, the properties of online games, exogenous variables, were identified by three factors: entertainment, security, participation and challenge. Second, we had input social interaction among gamers as another exogenous variables. Third, the gamer's satisfaction of online games was added to the research model as a mediating variable between exogenous variables and endogenous variables. Finally, gamer's intention to play influenced by satisfaction and social interaction was used as final endogenous variable. The data used for the empirical analysis were collected through questionnaires for Chinese under age 35 who enjoy the online games. The data used in the research were finally extracted from 195 questionnaires. The collected data were tested through the analysis of the measurement model (Step 1) and the analysis of the structural model (Step 2). The covariance structure equation model (SEM) was used for the analysis. The measurement model and structural model were evaluated by the maximum likelihood method. Results - The results of the empirical analysis are as follows. The satisfaction of online games were entertainment and security had a significant effect to satisfaction; but participation and challenge and social interaction had no significant effect on satisfaction. The social interaction among gamers and the satisfaction with online games have a significant influence on the intention to play online games. As a result, the attributes of the game were affecting the intention to play the game after satisfaction. Social interaction influenced the intention to play online games rather than satisfaction itself. Conclusions - This study provide some practical implications for the new companies who want to enter the online game industry and seek to competitiveness in China, and provide theoretical implications on the role of interaction among gamers in the study of online games.

• Management & Information Systems Review
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• v.31 no.1
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• pp.221-246
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• 2012

The study examines the effects that non-audit service and firm's ownership structure might have on the value relevance directly or indirectly. This investigation is based on prior research which suggests that the audit firms' non-audit services is likely to adversely affect investors' perceptions of the credibility of financial reporting and that corporate governance are likely to mitigate the adverse this kind of non-audit services effects. The sample consists of non-banking firms listed on the Korea Exchange that reported annual financial statements over the period from 2004 to 2008. In the setting, stock returns as proxy for capital market response, auditor quality(measured as the discretionary accruals) is endogenously determined. This study employs a structural equation model to take into account the endogenous variables under study. The analysis influences through the path analysis that ownership structure suppress the market response through audit quality and also the non-audit service have influence on the market response through audit quality. The results of this study contribute to the literature in the following ways. First, this provides direct evidence that there is a negative association between audit firms' client importance and the value relevance. Second, the findings that the negative association is attenuated for audit quality support the findings of prior studies which present that corporate governance provide higher credibility of financial reports.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.3
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• pp.139-148
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• 2000

In this paper, the interaction of oblique incident waves with a bottom-mounted and fluid-filled flexible membrane structure is investigated in the frame of linear hydro-elastic theory. The static shape of a membrane structure containing the fluid of a specific density is initially unknown and must be calculated before the hydrodynamic analysis. To solve hydrodynamic problem, the fluid domain is divided into the inner and outer region. The inner solution based on discrete membrane dynamic model and simple-source distribution over the entire fluid boundaries is matched to the outer solution ba~ed on an eigenfunction expansion method. The numerical results were compared to a series of Ohyama's experimental results. The measured reflection and tran¬smission coefficients reasonably follow the trend of predicted values. Using the computer program developed, the performance of a bottom-mounted and fluid-filled flexible membrane strocture is tested with various system parameters (membrane shape, internal pressure, density ratio) and wave characteristics (wave frequencies, incident wave angle). It is found that a bottom-mounted and fluid-filled flexible membrane structure can be an effel;tive wave barrier if properly designed.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.500-509
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• 2015

The purpose of this study is to induce a indicator related to the response, handling and management which are appeared on each step of business enforcement in Reconstruction projects. Then, it aims to appropriately and reasonably resolve the conflicts of reconstruction business with relevant subjects. These projects physician satisfaction and continual business was going to have the impact that any analysis of the structure in an evaluation. In addition, this study analyzes the impact structure on the business satisfaction and a intention for continuous business through this evaluation. This study sets a operational hypothesis in order to verify the relationship between the variables. then, it creates the structural model by using the Smart PLS 3.0. After analyzing the impact structure, this study adopts the final Five hypothesis which shows (+) path coefficient as set in the hypothesis and test statistic above 1.65. then, The 'Approval for union establishment(H1)' has a path coefficient of 0.127. In addition, the 'Approval for business enforcement(H2)' has a path coefficient of 0.343. The 'Management and disposition plan(H4)' has a path coefficient of 0.145. and the 'External Factors(H6)' has a path coefficient of 0.124. Finally, The 'satisfaction of business' which affects the 'intention for continuous business(H7)' has a path coefficient of 0.727.

• Journal of the Korean GEO-environmental Society
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• v.24 no.7
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• pp.5-14
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• 2023

Recently, earthquakes have occurred frequently in worldwide. These earthquakes cause various forms of natural and physical damage. In particular, liquefaction in which the ground shows liquid-like behavior causes great damage to the structure. Accordingly, various liquefaction damage reduction methods are being studied and developed. Therefore, in this study, a method of reducing liquefaction damage in the event of an earthquake applicable to existing structures was studied using the sheet pile method. The 1-G Shaking table test was performed and the ground was constructed with Jumunjin standard sand. A two-story model structure was produced by applying the similitude law, and the input wave applied a sine wave with an acceleration level of 0.6 g and a frequency of 10 Hz. The effect of reducing structure damage according to various embedded depth ratio was analyzed. As a result of the study, the structure settlement when the ground is reinforced by applying the sheet pile method is decreased by about 71% compared to when the ground is not reinforced, and the EDR with minimum settlement is "1". In addition, as the embedded depth ratio is increased, the calculation of the pore water pressure in the ground tends to be delayed due to the sheet pile. Based on these results, the relationship with structural settlement according to the embedded depth ratio is proposed as a relational equation with the graph. The results of this study are expected to be used as basic data in developing sheet pile methods applicable to existing structures in the future.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.69-79
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• 2019

In Korea, more than 60% of the whole lands are mountainous area. Since many decades ago, hydroelectric power plants have been constructed and eco-friendly energy has been produced. Hydropower can cope with the rapidly changing energy supply and demand, and produce eco-friendly energy. However, when the reservoir is built, it is often inevitable to damage the environment due to construction of large structure. In this study, the optimal reservoir operation model was developed to maximize power generation by monthly operation for long-term operation planning. The dam operation model was developed using the linear programming which is widely used in the optimal resources allocation problems. And the reservoir operation model can establish monthly operation plan for 1 year. Linear programming requires both object function and constraints to be linear. However, since the power generation equation is nonlinear, it is linearized using the Taylor Expansion technique. The optimization results were compared with the 2009-2018 historical data of five hydropower reservoirs. As a result, the total optimal generation is about 10~37% higher than the historical generation.

• The Journal of Fisheries Business Administration
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• v.25 no.1
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• pp.37-59
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• 1994

Many studies to cope with the present problems of Korean coastal and offshore fisheries has been performed, but these were done partly in necessities and general studies for Korean inshore and offshore fisheries are in early stage. Most of these studies adopted analytical way of approach for each fishery individually and they could not reflect the effect of correlated interaction among fisheries on the several common species/stocks, and thus optimal effort allocation was impossible. To consider general fisheries and optimal effort allocation among competing mixed species, a linear programming (LP) approach is applied in this study and introduced into 16 important inshore and offshore fisheries with 13 constraining species which were chosen by annual yield order. This study is not based on the biological interaction among species (i.e., prey - predator system) but the technological interaction between species and fishing efforts. For the application of LP model in these fisheries, the standardization of fishing efforts through different fishing gears could not be successful and a new way of effort standardization through CPUE for vessel tonnage was originated. Total standardized fishing effort on a particular species i, Ei, is computed as the linear summation of standardized fishing effort generated by each fishery j. That is, (equation omitted) where $f_{j}$ is the total vessel tonnage of fishery j and aij is the coefficients contributing to the standardized fishing effort per ton for species i taken in fishery j. The total fishing effort level on species i due to both directed fishing and by - catch can thus be accounted in the aij's. Optimal effort allocation among the j fisheries may be considered a minimizing problem (minimize $\Sigma$ $f_{j}$), subject to the constraints that standardized fishing effort levels on particular species are maintained at, above, and below certain predefined levels. Fishing effort goals for individual species can be based on various biological and/or economic criteria, i.e., fishing effort level generating maximum sustainable yield and/or maximum economic yield. But in this study the $F_{0.1}$ criteria which was accepted as an approximate level for $F_{mey}$ by Outland and Boerema's (1973) study. The findings of this study are, (1) LP model can be applied to the Korean inshore and offshore fisheries giobally. (2) Through a new way of combining multiple different fisheries' efforts for a particular species together generating standardized fishing effort, Schaefer curve could be applied to the complex system successfully. (3) The results of this study for total reduction scale were mostly the same as those of prior studies, but different much from the individual scales of reduction. This study showed the necessities for exploitation of more concrete parameters to put into consideration of profitability of fisheries and social factors, and this model can be modified according to the actual constraints. Also, considering the age structure of stocks, this model can be developed into better one for better fisheries management.ent.