• Journal of Digital Convergence
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• v.20 no.5
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• pp.609-615
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• 2022

In this paper, we propose a monitoring system for illegal overseas direct purchase based on C2C transaction between individuals. The Customs Act stipulates that direct purchases from overseas are exempted from taxation only if they are less than a certain amount (US$150, but US$200 in the US) or are recognized as self-used goods. The act of reselling overseas direct purchase items purchased with exemption from taxation online, etc., is a crime of smuggling without a report. Nevertheless, the number of re-sells on online second-hand websites is increasing, and it is becoming a controversial social issue of continuous violation of the Customs Act. Therefore, this study collects unspecified transaction details related to overseas direct purchase, refines the data in a big data method, and designs it as a monitoring system through natural language processing, etc. analyzed. It will be possible to use it to crack down on illegal transactions of overseas direct purchase goods.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.2
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• pp.59-76
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• 2023

Since the COVID-19 era, the rise in apartment prices has been unconventional. In this uncertain real estate market, price prediction research is very important. In this paper, a model is created to predict the actual transaction price of future apartments after building a vast data set of 870,000 from 2015 to 2020 through data collection and crawling on various real estate sites and collecting as many variables as possible. This study first solved the multicollinearity problem by removing and combining variables. After that, a total of five variable selection algorithms were used to extract meaningful independent variables, such as Forward Selection, Backward Elimination, Stepwise Selection, L1 Regulation, and Principal Component Analysis(PCA). In addition, a total of four machine learning and deep learning algorithms were used for deep neural network(DNN), XGBoost, CatBoost, and Linear Regression to learn the model after hyperparameter optimization and compare predictive power between models. In the additional experiment, the experiment was conducted while changing the number of nodes and layers of the DNN to find the most appropriate number of nodes and layers. In conclusion, as a model with the best performance, the actual transaction price of apartments in 2021 was predicted and compared with the actual data in 2021. Through this, I am confident that machine learning and deep learning will help investors make the right decisions when purchasing homes in various economic situations.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.223-230
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• 2004

A shooting game is all game genres that hit targets through shooting. It include a lot of genres from a flying shot of game room to a personal shooting action game. In this point, a shooting game was regarded it as the origin of all game and it was developed from the early days of game. At present we can meet it in an electronic game room or personal computer, and mobile phone etc.. The popularity of shooting game caused to take aim by simple system, interface, and speedy play. Also it was enticed everyone to enjoy it easily. A shooting games is worked from old like ways until recently and a process of playing game is intuitive than another game. Therefore it popular with a PC player as well as persons of all levels. Beginners can train this game easily through direction such as control way of object, advent way of enemy aircraft and scroll way of background. But as an usability of working and controlling game, beginners of game development can pass over a shooting sense that shout and hit basically. And after design, they will feel that cannot convey realistic effect and thrill etc.. At a result, hitting sense happens to graphic elements and sound. Therefore a measure of effect on these elements is started from analysis of good shooting game. This study was to focus on the advance effect of hitting sense in shooting game through analysis centered for 'the Beetlewing' and '1945 Plus'.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.555-565
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• 2021

The goal of this study is to improve flow and noise performances of existing backward-curved blade centrifugal fan system used for circulating cold air in a refrigerator freezer by optimally designing airfoil shape. The unique characteristics of the system is to drive cold airflow with two volute tongues in combination with duct system in a back side of a refrigerator without scroll housing generally used in a typical centrifugal fan system. First, flow and noise performances of existing fan system were evaluated experimentally. A P-Q curve was obtained using a fan performance tester in the flow experiment, and noise spectrum was measured in an anechoic chamber in the noise experiment. Then, flow characteristics were numerically analyzed by solving the three-dimensional unsteady Navier-Stokes equations and noise analysis was performed by solving the Ffowcs Williams and Hawkins equation with input from the flow simulation results. The validity of numerical results was confirmed by comparing them with the measured ones. Based on the verified numerical method, blade inlet and outlet angles were optimized for maximum flow rate using the two-factor central composite design of the response surface method. Finally, the flow and noise performances of a prototype manufactured with the optimum design were experimentally evaluated, which showed the improvement in flow and noise performance.

• The Journal of Bigdata
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• v.8 no.1
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• pp.11-22
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• 2023

This research aimed to examine the public's perception of the "rate of sentence reduction for reasons of mental and physical weakness" and investigate if it aligns with the actual practice. Various sources, such as the Supreme Court's Courtnet search system, the number of mental evaluation requests, and the number of articles and comments related to "mental weakness" on Naver News were utilized for the analysis. The findings indicate that the public has a negative opinion on reducing sentences due to mental and physical weakness, and they are dissatisfied with the vagueness of the standards. However, this study also confirms that the court strictly applies the reduction of responsibility for individuals with mental disabilities specified in Article 10 of the Criminal Act based on the analysis of actual judgments and the number of requests for psychiatric evaluation. In other words, even though the recognition of perpetrators' mental disorders is declining, the public does not seem to recognize this trend. This creates a negative impact on the public's trust in state institutions. Therefore, law enforcement agencies, such as the police and prosecutors, need to enforce the law according to clear standards to gain public trust. The judiciary also needs to make a firm decision on commuting sentences for mentally and physically infirm individuals and inform the public of the outcomes of its application.