• Journal of KIISE:Databases
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• v.30 no.4
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• pp.408-419
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• 2003

Data warehouses are usually dedicated to the processing of quires issued by decision support system(DSS). The response time of DSS queries is typically several orders of magnitude higher than the one of OLTP queries. Since DSS queries are often submitted interactively, techniques for reducing their response time are important. The caching of query results is one such technique particularly well suited to the DSS environment. In this paper, we present a cache manager for such an environment. Specifically, we define a canonical form of query. The cache manager looks up a query based on the exact query match or using a suggested query split process if the query is found is non-canonical form or in canonical form, respectively. It dynamically maintains the cache content by employing a profit function which reflects in an integrated manner the query execution cost, the size of query result, the reference rate, the maintenance cost of each result due to updates of their base tables, and the frequency of such updates. We performed the experimental evaluation and it positively shows the performance benefit of our cache manager.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.93-108
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• 2016

Electric vehicle car sharing (EV-sharing) system is noted as an eco-friendly system of transportation in global warming crisis and has been practically implemented in some cities around the world. However, methodologies to find the efficient operation conditions of EV-sharing systems reflecting a typical characteristic 'charging' have not been fully investigated yet. In the paper a generalized model has been developed to identify optimal level of infrastructure for EV-sharing system which provides the optimum operation efficiency under service level constraints. From the simulation analysis based on the developed model the relationships between the operational variables to describe EV-sharing system have been identified and optimal capacity to maximize the operational efficiency have been found. From the analysis of simulation results it has been found that increases in the number of vehicles and chargers improve the service level until certain value beyond which increasing rate and the efficiency have been reduced. From the cost-revenue analysis the optimal numbers of vehicles and chargers have been identified which maximizes the annual operational profit.

• Korean Journal of Labor Studies
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• v.24 no.2
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• pp.293-319
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• 2018

This study analyzed the determinants of employment for the regular workers in the industrial type, and the results are as follows. First, 73.2% of companies use outsourcing as of 2015, and manufacturing (83.7%) is 20% p higher than non-manufacturing (63.7%). Over the past 10 years, the rate of outsourcing increased by 88.7% in manufacturing and 44.2% in non-manufacturing. Second, as a result of estimating the determinants of employment for regular workers, the variables of labor income distribution, operating profit, sales, R & D expenditure, foreign capital ratio significantly increase the employment of regular workers, while outsourcing, capital intensity, Were estimated to significantly reduce employment. Third, as a result of subdivision of industrial type and estimation of the effect of outsourcing on employment, it decreased employment of regular workers in all types. The size of influence was the biggest decrease in 'basic material type' in manufacturing industry and 'distribution service type' in non - manufacturing industry.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.1000-1003
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• 2014

As smart phones have became popular in recent years, use rate of smart phones application of mobile subscribers is now gradually increasing. Smart phones have a considerable effect on real life of users. Especially, mobile payment service using smart phones is outstanding in convenience because of its simple way to check out online. Therefore, in this paper, the database was designed for inquiring and making pre-order for take-out products based on connivence. This paper offers pre-order design to have order information standardized, menus which store owners can register and manage, and statistical data based on sales. It can be cost and time-efficient by using integrated pre-order system across all franchises. If this take-out pre-order system becomes more widely available, it will increase profit for both users and franchises due to cost and time efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.461-464
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• 2014

As smart phones have became popular in recent years, use rate of smart phones application of mobile subscribers is now gradually increasing. Smart phones have a considerable effect on real life of users. Especially, mobile payment service using smart phones is outstanding in convenience because of its simple way to check out online. Therefore, in this paper, the database was designed for inquiring and making pre-order for take-out products based on connivence. This paper offers pre-order design to have order information standardized, menus which store owners can register and manage, and statistical data based on sales. It can be cost and time-efficient by using integrated pre-order system across all franchises. If this take-out pre-order system becomes more widely available, it will increase profit for both users and franchises due to cost and time efficiency.

• The Journal of Bigdata
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• v.5 no.2
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• pp.231-240
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• 2020

With the development in the IT industry and the growth in the game industry, user's game data is recorded in seconds according to various plays and options, and a vast amount of game data can be analyzed based on Bigdata. Combined with business, Bigdata is used to discover new values for profit creation in various fields, but it is utilized in the game industry in insufficient ways. In this study, considering the characteristics of the subdivided lines, we constructed a win-loss prediction model for each line using the game data of League of Legends, and derived the importance of variables. This study can contribute to planning of strategies for general game users to get information about team members in advance and increase the win rate by using the record search sites.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.361-374
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• 2021

The purpose of this study is to analyze the efficiency and productivity of technological innovation activities of companies certified as innovative pharmaceutical companies by the government to diagnose their competitiveness and derive measures to strengthen them. This study collected pharmaceutical input (R&D expenditures and number of employees) and output (sale, operating profit and patent) data between 2017 and 2019 for 38 innovative pharmaceutical companies. This study analyzed them using the data envelopment analysis (DEA) method, Tobit model and the Malmquist Productivity Index (MPI). First, the DEA result of the innovative pharmaceutical companies show that between the value of the CCR model of the scale efficiency and the value of the BCC model to diagnose the internal operation efficiency is differences. Second, efficiency does not differ between corporate characteristics. Third, Tobit model shows that number of patents held have positive effects on efficiency. Forth, overall MPI is 0.89. This can be interpreted as the rate of TECI decreased 3%p and TCI has increased 4%p. The results of this study can be used as decision-making data for response strategies to improve efficiency by identifying the cause of inefficiency and presenting target values.

• Journal of Platform Technology
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• v.11 no.4
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• pp.62-70
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• 2023

This research is one of a series of studies to develop a system to help agricultural producers and sellers determine when and how much to ship products to the wholesale market to maximize their profit. The purpose of this research is to incorporate the time-varying quality change effect, which was not used in the previous agricultural and marine product shipping model. The researchers developed four models to measure the quality change effect: quality declining steadily over time, quality declining rapidly at first and then slowly, quality declining first slowly and then rapidly, and quality rising over time and then decreasing again. According to the results of an empirical analysis of the effect of each model's quality change effect on shipments for apples traded in the Garak Wholesale Market from 2014 to 2021, statistical significance was found in the quality change effect of all four models. And there was no significant difference in explanatory power between the four models. Therefore, any of the four models should be introduced into the decision-making system for shipping time for apples.

• 한국노년학
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• v.30 no.4
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• pp.1329-1344
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• 2010

This study is intended to find out how production people have been creating senior radio program. For this purpose, the study set up the three research questions and employed in-depth interviews with ten production people: First, production people find out senior radio listeners who have been very royal attendance of the program for a long time. And they examined senior listeners prefer to listen about health care, information about elderly life and singing contest. They have been made para-social interaction with master of ceremonies (MC). Second, unlike other radio program, the senior radio program has concentrated on the radio station's image and public interest rather than financial profit and viewing rate. Normally, it was known that radio program for senior used carried on break of the day. But some program has been broadcasted on prime time in the afternoon. Target audience of senior radio program has been expanded over the forties and the fifties from sixties. Thirdly, in general the role of producer is critically important to produce program. However, MC and scriptwriter are far more experienced and specialized on the field than producer in radio program for senior.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.67-74
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• 2024

As the number of coffee shops increases, many people are studying or working at coffee shops. Coffee shop operators have been required to analyze customer visits due to customer turnover and profit problems. Methods such as image analysis, QR code authentication, and Bluetooth beacon have been proposed for these statistics and analysis. However, it is difficult to use due to problems such as invasion of privacy and low accuracy. Therefore, in this study, to solve these problem and provide more accurate in-store congestion information, we propose a crowding measurement method of coffee shop using high frequency signal. There is an advantage in that a high frequency signal replaces the Bluetooth signal, and the transmission range of the signal is limited to the store, thereby increasing the accuracy of the method. To verify the performance of the proposed system, we conducted a comparative experiment with a Bluetooth based system, and as a result, the proposed method showed lower misrecognition rate. Thus, the proposed method will be an effective useful service for providing information on crowding at coffee shops and processing statistics.