• Economic and Environmental Geology
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• v.57 no.5
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• pp.487-497
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• 2024

Pore-scale reactive transport modeling is a powerful tool used to analyze micro-scale processes where fluid flow and geochemical reactions occur. Despite its capability to examine complex hydrological and geochemical system behavior, the high computational demands for these simulations present a significant limitation. To overcome this challenge, this study evaluated artificial neural network (ANN)-based surrogate models to replace geochemical reaction calculations, which consume the majority of computational time in reactive transport simulations. The study considered two ANN models: a combined model (CM) that simultaneously accounts for mineral dissolution/precipitation and solute adsorption reactions, and an independent model (IM) that treats these reactions independently. The performance of these models was compared using metrics, including mean squared error (MSE), coefficient of determination (R²), and mass balance errors. Results indicate that IM demonstrates superior accuracy compared to CM. This finding suggests that instead of constructing a single complex model for the entire geochemical reaction network, pore-scale geochemical reactions can be effectively replaced by combining individual neural network models trained for specific reactions.

• The Journal of Bigdata
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• v.8 no.1
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• pp.23-34
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• 2023

Nowadays, the Designated Driver Services employ dynamic pricing, which adapts in real-time based on nearby driver availability, service user volume, and current weather conditions during the user's request. The uncertain volatility is the main cause of price increases, leading to customer attrition and service refusal from driver. To make a good Designated Driver Services, development of a demand forecasting model is required. In this study, we propose developing a demand forecasting model using data from the Designated Driver Service by considering normal and peak periods, such as rush hour and rush day, as prior knowledge to enhance the model performance. We propose a new methodology called Time-Series with Conditional Probability(TSCP), which combines conditional probability and time-series models to enhance performance. Extensive experiments have been conducted with real Designated Driver Service data, and the result demonstrated that our method outperforms the existing time-series models such as SARIMA, Prophet. Therefore, our study can be considered for decision-making to facilitate proactive response in Designated Driver Services.

• Journal of Environmental Policy
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• v.6 no.4
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• pp.103-127
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• 2007

This study presents the political economics models to explore the political landscape of special interest groups influencing the government's decision making process for implementing international environmental standard. Starting with the popular menu-auction types of lobbying frameworks in the literature, the study extends its scope of research to multi-principal and multi-agency based international interest group politics and its hybrid case in order to bring the interaction of the relevant interest politics to the fore. Within a specific factor model of international trade between 2 small open economies, we compare the political equilibrium environmental standards in different institutional frameworks which can be feasible in the sense of recently growing role of environmental interest group. Although the conventional finding suggests that cooperative bargaining between the two countries can attain the globally optimal level of the standard, the paper rather explains that the cooperation between the national interest groups and the hybrid case also generate the stricter standard then national interest politics usually do.

• The Korean Journal of Financial Management
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• v.15 no.1
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• pp.245-261
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• 1998

본 논문은 다기간 대리모형에서 나타날 수 있는 대리비용 중에서 대리인과 위임자의 의사 결정고려기간(decision-making horizon)의 차이로 인해서 발생할 수 있는 과소투자유인을 연구 대상으로 하고 있다. 대리인인 경영자는 자신의 명성을 고려해서 투자효과가 자신의 임기내에 나타나는 투자안에 높은 관심을 가질 것이다. 그런데 계속기업을 전제로 하면 대리인인 경영자는 위임자인 주주보다 투자의사결정시 고려하는 기간이 짧아서 과소투자의 가능성이 존재한다. 동적최적화 기법을 이용한 이론적 모형의 결과도 대리계약기간이 짧을수록 투자수준이 낮을 것으로 나타났다. 이러한 내용을 한국상장기업들을 대상으로 임원근속기간과 설비투자수준의 관계에 대해서 실증분석한 결과, 이론적 기대와 일치하지만 통계적 유의성은 낮은 편이었다. 이같은 결과는 전문경영체제가 확립되어 있지 않은 한국기업환경의 특성에 기인한다고 생각된다.

• Journal of Technology Innovation
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• v.20 no.3
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• pp.57-91
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• 2012

This paper investigates determinants of litigation success in the two distinctive types of patent litigations, ex-parte and inter-parte cases, which are brought in the process where a filed application becomes a valid patent right. We regress winning rates of patent applicants on the characteristics of firms, trials, patent lawyer, and patent itself, using a probit model with sample selections. The paper finds that the relative suit rate of a firm, time to be sued, changes of patent agents by applicants, and multiple agents among explanatory variables affect ex-parte reexamination and in-parte post-grant patent trials differently in the point of average marginal effects. These variables lower the probability of applicant's victory in the ex-parte cases, while they raise the probability in the inter-parte trials. However, the experience that agents represent applicants is a winning rate-increasing factor both in inter-parte and ex-parte reexamination, unexpectedly. This result cannot be applied to the entire domain of the variable, since sample selection effects are reflected in the result. The number of claim increases the winning probability of the applicant in the both types of patent litigations. This study has some limitations because it ignores the information on the legal person to which a patent agent belongs, and confined agent's experience to patent filing. We leave it future studies to investigate the effects of lawsuit experience of patent agent, and those of characteristics of the law firm to which individual patent lawyer is affiliated.

• Korean Journal of Social Welfare Studies
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• v.43 no.2
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• pp.87-111
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• 2012

This study designed a mediating pathways models to examine the theory, 'the influence of attachment relationship between adolescents and their parents affects on adolescents' psycho-social adjustment through the mediating variable of optimism'. Authors tried to examine if this theory is applied to group-home adolescents who live with surrogate care-givers instead of their parents. For this study, two models, 'Psychological Adjustment Model' and 'Social Adjustment Model' were constructed. Each model has path, 'Attachment with Care-givers → Psychological Adjustment' and ''Attachment with Care-givers → Social Adjustment' respectively. 'Optimism' is mediating variable in between these two variables. The results were very clear. In two models, no direct effects from 'Attachment' to 'Psychological Adjustment' and from 'Attachment' to 'Social Adjustment' were found. However, indirect effects from 'Attachment' to 'Psychological Adjustment' and from 'Attachment' to 'Social Adjustment' were statistically significant through the mediating variable of 'Optimism'. This study suggests that more research on 'Optimism' which has not been focused among social welfare researchers needs to be followed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3417-3426
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• 2012

This study aims to determine how ownership structure (share-holding ratio of insiders, foreigners) affects agent costs (the portion of asset efficiency or non-operating expenses) through empirical analysis. However, as existing studies on correlations between ownership structure and agent costs adopted Pooled OLS Model, this study focused on additionally formulating Fixed Effect Model and Random Effect Model aimed to reflect the time of data formation and corporate effects as study models based on verification results on the suitability of Pooled-OLS Model before comparative analysis for the purpose of improvement of credibility and statistical validity of the results of empirical analysis based on the premise that the Pooled OLS Model is not reliable enough to verify massive panel data. The data has been accumulated over 10 years from 1998 to 2007 after the IMF crisis hit the nation, from a subject 331 companies except for financial institutions. As a result of the empirical analysis, verification of the suitability of model has determined that the Random Effect Model is appropriate in terms of asset efficiency among agent costs items. On the other hand, the Fixed Effect Model is appropriate in terms of non-operating costs. As a result of the empirical analysis according to the appropriate model, no hypothesis adopted in the Pooled OLS Model has been accepted. This suggests that developing an appropriate model is more important than other factors for the purpose of generating statistically significant empirical results by showing that different empirical results are produced according to the type of empirical analysis.

• Journal of Venture Innovation
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• v.6 no.2
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• pp.159-172
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• 2023

This study aimed to empirically analyze the factors influencing the career search intention of college students. The research model was derived based on the Social Cognitive Career Theory (SCCT), considering the unique characteristics of university students. Self-efficacy and outcome expectations were investigated as independent variables, while mastery experience, verbal persuasion, vicarious learning, and positive emotions were considered as antecedent variables. A survey was conducted among college students in the metropolitan area, resulting in 217 valid responses for analysis. Empirical analysis was conducted using structural equation modeling with AMOS 24. The findings revealed that mastery experience, vicarious learning, and positive emotions had a significant positive effect on self-efficacy. Furthermore, verbal persuasion and positive emotions significantly influenced outcome expectations. However, the impact of verbal persuasion on self-efficacy was not found to be significant, and the relationship between mastery experience, vicarious learning, and outcome expectations was not examined. Both self-efficacy and outcome expectations were found to have a significant positive effect on career search intention, with outcome expectations exhibiting a stronger influence. The empirical results contribute to the understanding of college students' career exploration and provide implications for academic and practical contexts.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.465-465
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• 2022

하천 미세플라스틱 측량을 위해 많은 연구자들이 노력하고 있으나 모든 하천에서의 미세플라스틱 실측은 현실적으로 어렵다. 미세플라스틱의 물 환경에 대한 영향을 이해하고 예측하기 위해서는 오염원과 오염원 운송 매개체로서 물 환경에 존재하는 플라스틱의 물리적 거동을 아는 것이 매우 중요하다. 따라서 미세플라스틱의 하천 내 물리적 거동을 과학적으로 규명하고 하천 미세플라스틱오염을 예측가능한 물리모형의 도출이 요구된다. 본 연구에서는 물리기반 하천수질모형인 Water Quality Analysis Simulation Program(WASP8)의 Advanced Eutrophication Module을 이용하여 상용 수질 물리모형의 하천에서의 미세플라스틱 거동 모의 가능성을 검토하였다. 이를 위해 미세플라스틱과 유사한 거동을 보이는 수질지표를 대리인자로 하여 기존에 알려져 있는 물리모형(WASP8의 Advanced Eutrophication Module)을 이용해 미세플라스틱의 하천 내 거동을 설명하고 예측 가능한 모델을 개발하고자 한다. 본 연구결과로부터 하천 미세플라스틱 오염 분석 및 예측의 기초자료를 마련한다.

• Environmental and Resource Economics Review
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• v.16 no.1
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• pp.3-26
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• 2007

This paper analyzes the effects of asymmetric reimbursement in a delegate model where the lawyers for a citizen and a polluting firm work on a contingent-fee basis. The major findings from the paper are as follows: (i) the asymmetric reimbursement triggers environmental conflicts by increasing the citizens' expected surplus; (ii) it enhances the possibility of settlement by decreasing the magnitude of expected loss less expected surplus; (iii) settlements reduce the total litigation effort levels, thus curtailing the rent dissipation; (iv) The total litigation effort levels increase if the conflicts result in trials rather than settlements.