• Journal of Nutrition and Health
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• 제39권3호
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• pp.299-306
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• 2006

This study was done to investigate the use of nutritional supplements (NS) in Korean elite soccer players using an anonymous questionnaire. NS were classified into health supplements, manufactured health food supplements, chinese medicines & tonic foods, and nutrient supplements. Information was sought on the type of NS and factors that might influence supplement use including selected demographic parameters and health related variables. The data were collected from 241 athletes (aged $24.6{\pm}3.8$ years) in 9 professional soccer club. The prevalence of NS use among the subjects was 81.3%. Health supplements were used most frequently and nutrient supplement drug was the second one. Among the health supplements, weight/muscle gainer and calorie replacement product were most frequently used. Vitamin supplements were most frequently used among all nutrient supplement drugs. Users of NS were higher age (p<0.05) duration of exercise (p<0.05), and income (p<0.05) than non-users. The married (p<0.05) and a member of K-league (p<0.01) tended to have higher prevalence of NS use. The main adviser of NS were family (55.3%) and oneself (39%) instead of coach or sports nutritionist. Although NS use, only 26.2% certainly check up nutritional information on their used NS. Among the subjects, 84.5% of them felt that NS use were improved athletic performance, and 86.5% of them will to keep on taking supplement. These data suggest that a large number of elite soccer players use NS and these players may require education about healthy nutritional supplement practice and on the proper use of nutritional supplements.

• 한국컴퓨터정보학회논문지
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• 제24권4호
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• pp.35-43
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• 2019

The purposes of this study is to derive the influence factors of Virtual Reality(VR) technologies acceptance based on the study of unified theory of acceptance and use of technology and value-based acceptance model to test the use and acceptance of VR devices. The survey methods were used for this study, and the data from a total of 400 consumers were used for the analysis. And the structural equation model was used to analyze the data. The results of the study are as follows: First, benefit components perceived enjoyment(EN) and sacrifice components personal innovative(PI) of VR devices were positively related to perceived values and use intention of VR devices, although the benefit components performance expectancy(PE) was positively related to perceived values(PV) but was not positively related to the use intention of VR devices. Second, sacrifice components perceived cost(PC) and anxiety(ANX) of VR devices were negatively related to perceived value(PV), but were not negatively related to the use intention of VR devices. Third, perceived values was not obvious related to the use intention(UI) of VR devices. The results of this study contribute to the literature as a new attempt to examining the effect on consumer use intention in VR technology areas.

• 한국태양에너지학회 논문집
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• 제26권4호
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• pp.9-16
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• 2006

Geothermal-energy has been getting popular as a natural energy source for green buildings these days. Public building with gross area more than $3000m^2$, planned after March, 2005, should spend about 5% of total building cost for equipment run by natural energy source (e.g. geothermal, solar heat, solar power, etc) according to renewable energy promotion law in Korea. As a result geothermal-energy using heat pump system is emerging as a effective alternative for realistic and economic plan although design guidelines and construction code for the system is in progress and technical data is far from sufficient. The quantitative analysis on the performance of geothermal-energy using heat pump system is insufficient for appropriate design of it. In this paper, cooling performance of geothermal-energy using heat pump system of residential and retail etc. mixed-use building has been analyzed on the basis of temperature comparison between inlet and outlet of heat exchangers of the operating system. Additionally, dry-bulb temperature and relative humidity have been measured and analyzed together as an index of indoor thermal environment.

• Journal of Communications and Networks
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• 제5권3호
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• pp.187-196
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• 2003

We consider the use of error control coding in direct sequence-code-division multiple access (OS-COMA) systems that employ multiuser detection (MUO) and space diversity. The relative performance gain between Reed-Solomon (RS) code and convolutional code (CC) is well known in [1] for the single user, additive white Gaussian noise (AWGN) channel. In this case, RS codes outperform CC's at high signal-to-noise ratios. We find that this is not the case for the multiuser interference channel mentioned above. For useful error rates, we find that soft-decision CC's to be uniformly better than RS codes when used with DS-COMA modulation in multiuser space-time channels. In our development, we use the Gaussian approximation on the interference to determine performance error bounds for systems with low number of users. Then, we check their accuracy in error rate estimation via system's simulation. These performance bounds will in turn allow us to consider a large number of users where we can estimate the gain in user-capacity due to channel coding. Lastly, the use of turbo codes is considered where it is shown that they offer a coding gain of 2.5 dB relative to soft-decision CC.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.88-97
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• 2023

Traffic flow prediction is of great significance in urban planning and traffic management. As the complexity of urban traffic increases, existing prediction methods still face challenges, especially for the fusion of spatiotemporal information and the capture of long-term dependencies. This study aims to use the fusion model of graph neural network to solve the spatio-temporal information fusion problem in traffic flow prediction. We propose a new deep learning model Spatio-Temporal Information Fusion using Graph Neural Networks (STFGNN). We use GCN module, TCN module and LSTM module alternately to carry out spatiotemporal information fusion. GCN and multi-core TCN capture the temporal and spatial dependencies of traffic flow respectively, and LSTM connects multiple fusion modules to carry out spatiotemporal information fusion. In the experimental evaluation of real traffic flow data, STFGNN showed better performance than other models.

• 경영과학
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• 제32권1호
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• pp.15-33
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• 2015

Under complete information, introducing additional constraints to a portfolio will have a negative impact on performance. However, real-life investments inevitably involve use of error-prone estimations, such as expected stock returns. In addition to the reality of incomplete data, investments of most Korean domestic equity funds are regulated externally by the government, as well as internally, resulting in limited maximum investment allocation to single stocks and risk free assets. This paper presents an investment framework, which takes such real-life situations into account, based on a newly developed portfolio selection model considering realistic constraints under incomplete information. Additionally, we examined the effects of additional constraints on portfolio's performance under incomplete information, taking the well-known Samsung and SK group stocks as performance benchmarks during the period beginning from the launch of each commercial fund, 2005 and 2007 respectively, up to 2013. The empirical study shows that an investment model, built under incomplete information with additional constraints, outperformed a model built without any constraints, and benchmarks, in terms of rate of return, standard deviation of returns, and Sharpe ratio.

• Journal of Information Technology Applications and Management
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• 제11권2호
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• pp.15-27
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• 2004

Most software projects inevitably involve various types and degrees of uncertainty. Without proper risk assessment and coordination, software projects can easily run out of control and consume significant additional resource. Thus, risk management techniques are critical issues to information system researchers. Previous empirical studies of U.S. software firms support the adoption of development standardization and user requirement analysis techniques in risk-based software project management. Using data collected from software projects developed in Korea during 1999-2000, we conduct a comparative study to determine how risk management strategies impact software product and process performance in countries with dissimilar IT capabilities. In addition, we offer an alternative conceptualization of residual performance risk. We show that the use of residual performance risk as an intervening variable is inappropriate in IT developing countries like Korea where the role of late stage risk control remedies are critical. A revised model is proposed that generates more reliable empirical implications for Korean software projects.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1123-1131
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• 2008

A considerable amount of research has focused on the dimensionality of service failure and recovery construct. This paper is focused on service failure and recovery in the Korean native cattle and imported beef restaurant industry in the Korea. So, this paper has adapted Kau and Loh's Service recovery measurement scale so that restaurant managers can use it to determine how customers perceive the service quality in Korean native cattle beef restaurant and imported beef restaurant. The purpose of this research is to test the difference in pre-purchase expectation and post-purchase actual performance of 4 dimensions between the restaurants that sell the beef of Korean native cattle and imported cattle. The paired t -test is used to test difference of pre-purchase expectation and post-purchase actual performance for service recovery measurement scale's 4 dimensions of the 2 restaurant types. But, there is significant difference between pre-purchase expectation and post-purchase actual performance in the 2 restaurant types.

• 한국컴퓨터정보학회논문지
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• 제24권8호
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• pp.1-8
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• 2019

Modern computers provide tremendous computing capability and a large memory system. Hybrid memories consist of next generation memory devices and are adopted in high performance systems. However, the increased complexity of the microprocessor makes it difficult to operate the system effectively. In this paper, we propose a simple data migration method called Bandwidth-aware Data Migration (BDM) to efficiently use memory systems for high performance processors with hybrid memory. BDM monitors the status of applications running on the system using hardware performance monitoring tools and migrates the appropriate pages of selected applications to High Bandwidth Memory (HBM). BDM selects applications whose bandwidth usages are high and also evenly distributed among the threads. Experimental results show that BDM improves execution time by an average of 20% over baseline execution.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.917-918
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• 2009

This study evaluated the level of performance improvement in the form of a simulated experiment by adding fixed node in the middle of the network as a way to improve mobile ad.hoc network performance. The result showed that the performance level was much higher when fixed node was used together than when mobile node was used only, and the comparison of the mobile speed of mobile node also showed that use of fixed node together had higher performance. Moreover, the evaluation in accordance with the number of fixed node showed that more number of fixed node had shorter time delay. Further study following this on how many fixed node should be added on the ad.hoc network will ensure establishment of more reliable ad.hoc network.