• Korean System Dynamics Review
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• v.6 no.1
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• pp.99-123
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• 2005

Although the generation market is competitive, the power market is easily exercised the market power by one generator due to its special futures such as a limited supplier, large investment cost, transmission constraints and loss. Specially, as Korea Electric industry restructuring is similar US competitive wholesale electricity market structure which discovered the several evidences of market power abuse, when restructuring is completed the possibility that market power will be exercised is big. Market power interferes with market competitions and efficiency of system. The goal of this study is to investigate the market price effects of the potential market power and the proposed market power mitigation strategy in Korean market using the forecasting wholesale electricity market model. This modeling is developed based on the system dynamics approach. it can analyze the dynamic behaviors of wholesale prices in Korean market. And then it is expanded to include the effect of market condition changed by 'strategic behavior' and 'real time pricing.' This model can generate the overall insights regarding the dynamic impact of output withholding by old gas fire power plant bon as a marginal plant in Korean market at the macro level. Also it will give the energy planner the opportunity to create different scenarios for the future for deregulated wholesales market in Korea.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.928-931
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• 2014

The detection of human behavior from social media revolutionized health, business, criminal and political prediction. Significance of it, in incentive transformation of public opinion had already proven for developed countries in improving democratic process of elections. In $3^{rd}$ World countries, voters poll votes for personal interests being unaware of party manifesto or national interest. These issues can be addressed by social media, resulting as ongoing process of improvement for presently adopted electoral procedures. On the optimistic side, people of such countries applied social media to garner support and campaign for political parties in General Elections. Political leaders, parties, and people empowered themselves with social media, in disseminating party's agenda and advocacy of party's ideology on social media without much campaigning cost. To study effectiveness of social media inferred from individual's political behavior, large scale analysis, sentiment detection & tweet classification was done in order to classify, predict and forecast election results. The experimental results depicts that social media content can be used as an effective indicator for capturing political behaviors of different parties positive, negative and neutral behavior of the party followers as well as party campaign impact can be predicted from the analysis.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.620-632
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• 2001

This paper proposes a mediator system which can provide a view management function in the today's heterogeneous computing environment including operating system database management systems and other software. while most mediators use view modification mechanism only, the use of view materialization is also considered in this research. In order to optimize the management cost for materialized views the proposed method applies a decay factor for modeling the access behaviors of views In other words, the most recently access pattern gets the highest attention in the optimization process all the necessary it with the CORBA.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.65-72
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• 2009

Component based development has increasingly become important in the software industry. However, in the current component based development approach with UML, the absence of behavioral description of components brings about a cost problem which causes semantic errors on the testing phase. Accordingly we cannot grasp the usage pattern of component by its provided interfaces which refer to an abstraction of software component. And we cannot guarantee the behavioral conformance of the provided and required interfaces of components. In order to solve these problems, we describe the behaviors of component interfaces by state machine diagram and guarantee their behavior conformance at the modeling phase. We also propose a method to guarantee the behavior conformance of component interfaces with concept of observation equivalence and invocation consistency. And we provide an analyzing tool which checks interface behavior conformance.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.251-256
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• 2012

Hanging sleepers are frequently observed in the ballasted track with the rail of high rigidity. These hanging sleepers at the high speed line could cause such large dynamic force compared to those at the conventional line. This dynamic force would, in turn, deteriorate train running stability as well as riding comfort, and accelerate irregularity of track and failure of track materials, leading to a sharp increase in track maintenance cost. When the wheel-rail contact spring exhibits nonlinear behavior and some components of the system like hanging sleeper exhibit bi-linear behaviors, an effective analytical method is proposed for train-track interactions. The verification of the present method is carried out comparing numerical results by the present method and those by Ono's method of RTRI.

• Journal of Korean Clinical Health Science
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• v.9 no.2
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• pp.1486-1492
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• 2021

Purpose: By investigating oral health knowledge and oral health behavior of orthodontic patients, we intend to identify factors that affect their satisfaction with orthodontic treatment and use them as fundamental data for improving the satisfaction of orthodontic patients. Methods: Busan from February 1st to March 31st, 2021. Dental disease in Gyeongsangnam-do. A self-contained survey was conducted on patients undergoing orthodontic treatment in the clinic. A total of 185 copies were analyzed. Using the lBM SPSS Statistics 21 program, multiple regression analysis was conducted by setting oral health knowledge and oral health behavior as independent variables to determine factors affecting remedial treatment satisfaction. Results: The satisfaction level of orthodontic treatment was 1.53 points higher than 'understanding the cost of orthodontic treatment' and 'smooth relationship with related staff while receiving orthodontic treatment' was low at 1.23. The average calibration satisfaction was 1.34. Factors affecting remedial treatment satisfaction were shown in the order of oral health behavior (p<0.000), educational experience (p<0.010), gender (p<0.015) and oral health knowledge (p<0.020). Conclusions: Through the above results, it is necessary to develop programs to improve oral health knowledge through customized individual oral health education by enhancing individual oral health behaviors of individuals.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.141-146
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• 2021

Supercritical fluid has excellent dissolving power for various materials based on low viscosity and high diffusion coefficient and is used as solvents in various chemical processes. However, its industrial application can be very tricky because the design, especially the size of the supercritical apparatus, should be carefully chosen to optimize the cost and the production of supercritical fluidic state. And the first step of the supercritical fluid apparatus design is to choose the appropriate size of the reactor vessel to produce supercritical fluid above its critical pressure and temperature. Therefore, this study aims to analyze thermodynamic behaviors of dichloromethane based on ideal gas, van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson equations of state. The correlation between the volume and pressure of dichloromethane at 200℃ was revealed and it can be used to design the optimized size of the supercritical apparatus for industrial production.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.776-792
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• 2021

Conventional integral effect test facilities were constructed to enable the precise observation of thermal-hydraulic phenomena and reactor behaviors under postulated accident conditions to prove reactor safety. Although these facilities improved the understanding of thermal-hydraulic phenomena and reactor safety, applications of new technologies and their performance tests have been limited owing to the cost and large scale of the facilities. Various nuclear technologies converging 4th industrial revolution technologies such as artificial intelligence, drone, and 3D printing, are being developed to improve plant management strategies. Additionally, new conceptual passive safety systems are being developed to enhance reactor safety. A new integral effect test facility having a noticeable scaling ratio, i.e., the (UNIST reactor innovation loop (URI-LO), is designed and constructed to improve the technical quality of these technologies by performance and feasibility tests. In particular, the URI-LO, which is constructed using a transparent material, enables better visualization and provides physical insights on multidimensional phenomena inside the reactor system. The facility design based on three-level approach is qualitatively validated with preliminary analyses, and its functionality as a test facility is confirmed through a series of experiments. The design feature, design validation, functionality test, and future utilization of the URI-LO are introduced.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.18-25
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• 2020

This study investigated the structural behaviors and safety of an electro-mechanical linear actuator and a load simulator with a plate spring. The material and dimensions of the plate spring were determined by theoretically calculating the stress and torsional angle for the rating load of the actuator. Thereafter, a flexible multibody dynamics (FMBD) analysis was conducted on the linear actuator and load simulator to confirm the performance of the load simulator and acquire the reaction forces acting on the actuator and simulator. The structural safety of the linear actuator and load simulator was evaluated via finite element analysis using the aforementioned reaction forces. Consequently, the proposed linear actuator and load simulator were determined to be structurally safe; however, the safety factors for the actuation rod and the housing on the actuator were excessively high. Therefore, the weight and cost must be reduced to improve their design parameters in the future.

• Journal of Labour Economics
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• v.44 no.1
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• pp.169-204
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• 2021

We empirically verified whether there are different educational investment behaviors according to university admissions, using the Korean Education and Employment Panel data. The results are as follows; the average annual private education cost and the average amount of time spent studying alone per week of rolling admission type were lower than those of regular admission type. Also, rolling admission applicants had longer leisure and sleeping hours, such as watching TV and using computers. These results show the possibility that the university admission system will change the educational investment behavior. Furthermore, there is a possibility to induce the human capital investment to be made efficiently.