• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.34-49
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• 2015

Market means of spectrum trading have been utilized as a vital method of spectrum sharing and access in future cognitive radio system. In this paper, we consider the spectrum trading with multiple primary carrier providers (PCP) leasing the spectrum to multiple secondary carrier providers (SCP) for a short period of time. Several factors including the price of the resource, duration of leasing, and the spectrum quality guides the proposed model. We formulate three trading policies based on the game theory for dynamic spectrum access in a LTE based cognitive radio system (CRS). In the first, we consider utility function based resource sharing (UFRS) without any knowledge of past transaction. In the second policy, each SCP deals with PCP using a non-cooperative resource sharing (NCRS) method which employs optimal strategy based on reinforcement learning. In variation of second policy, third policy adopts a Nash bargaining while incorporating a recommendation entity in resource sharing (RERS). The simulation results suggest overall increase in throughput while maintaining higher spectrum efficiency and fairness.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.3
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• pp.57-68
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• 2012

The recent proliferation of various smart devices like the smartphone, tablet PC, and smart TV enables consumers to download various applications from the network and to access private files stored in their desktop server at any time and at any place. The trend of ubiquitous access seems to have become stronger and more diversified toward a ubiquitous network computing environment with the aggressive deployment of commercial cloud services. Recently, many Korean network service providers launched commercial B2C public cloud services, which were widely adopted by smart device users. They include Daum cloud, N drive, ucloud, and uplus box, mostly provided by major Korean telecom companies and portals. This paper aims to explore consumers' adoption behaviors toward the B2C public cloud services that were recently deployed in the Korean market. In order to achieve the goal, we identified key influencing factors that affect the consumers' adoption behaviors, based on an extension of the technology acceptance model (TAM). Several hundred smart device users were surveyed to test the generic regression model with the extended set of TAM variables.

• Journal of Communications and Networks
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• v.17 no.4
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• pp.419-427
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• 2015

There have been increases in the elderly population worldwide, and this has been accompanied by rapid growth in the health-care market, as there is an ongoing need to monitor the health of individuals. Wireless body area networks (WBANs) consist of wireless sensors attached on or inside the human body to monitor vital health-related problems, e.g., electrocardiograms (ECGs), electroencephalograms (EEGs), and electronystagmograms (ENGs). With WBANs, patients' vital signs are recorded by each sensor and sent to a coordinator. However, because of obstructions by the human body, sensors cannot always send the data to the coordinator, requiring them to transmit at higher power. Therefore, we need to consider the lifetime of the sensors given their required transmit power. In the IEEE 802.15.6 standard, the transmission topology functions as a one-hop star plus one topology. In order to obtain a high throughput, we reduce the transmit power of the sensors and maintain equity for all sensors. We propose the multiple-hop transmission for WBANs based on the IEEE 802.15.6 carrier-sense multiple-access with collision avoidance (CSMA/CA) protocol. We calculate the throughput and variance of the transmit power by performing simulations, and we discuss the results obtained using the proposed theorems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.941-949
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• 2007

By the newly emerging Network access technology, we face the new heterogeneous network environment. The required level of service quality and diversity are now multiplied by the increment of wireless service subscribers. Focusing on the co-existence of multiple access network technology and the complex service needs of users, the wireless service operators should present the stable service quality for every user. The service operators should build the new operation framework which combines the pre-established networks and newly adopted ones. Our problem is finding the optimal heterogeneous network operation framework. We suggest a market-based marginal cost function for evaluating the relative value of resource of each network and develop the whole new heterogeneous network operation framework.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.18-25
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• 2004

The purpose of this article is twofold: 1) to provide nutrition professionals with the history of how the concept of sustainable diets was introduced to the nutrition profession and 2) to describe how different sustainable agricultural practices offer potential for improving human nutrition and health. The idea of connecting sustainable agriculture With the promotion of human nutrition and health is not new. It is a concept that was introduced to the nutrition profession more than 20 years ago. To foster healthful, sustainable diets, consumers need to choose more whole foods. From the standpoint of nutrition and health, whole foods are naturally higher in fiber and lower in fat, sodium, sugar and additives compared to highly processed foods. From the standpoint of agricultural sustainability, whole foods bypass the high-energy costs of food processing and transportation. Organic farming systems offer potential benefits to human health through reducing farmers' exposure to pesticides and by increasing the total phenolic content in selected food crops. Participation in farmers' market nutrition programs and gardening has been associated with increased fruit and vegetable intake. Gardening may also be a way to increase access to fresh produce in low-income populations that do not have access to nutritious food outlets and to increase physical activity. Further research is needed to assess the human nutrition and health benefits of other types of sustainable agriculture strategies and to investigate the links among different agricultural practices with nutrient and total phenolic content in a wider variety of important food crops.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.853-860
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• 2012

In this paper, We shed light on radio spectrum policy and strategic planning of the United States of America and draw some conclusions. First of all, as the radio technology evolves with time, paradigm shift from command & control to market-based approach and spectrum commons is reviewed. Strategic spectrum planning of USA is also analyzed and some suggestions are drawn. In particular, USA plan for developing dynamic spectrum access(DSA) technologies and implementation of the test-bed for the DSA spectrum sharing is discussed, which improves the spectral utilization. Finally We deal with spectrum re-farming issue for mobile broadband and implicative points based on the National Broadband Plan.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.12
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• pp.51-61
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• 2021

If one is looking for an organization that will be responsive to community needs, stimulate economic growth, and raise people's income, cooperatives should be an obvious choice (Calkins & Ngo, 2005; Larocque et al., 2002). This paper investigates whether the households' income is affected by the access to cooperatives for the case of Phong Dien district, Can Tho city of Vietnam. Data used are directly collected from 250 households that are both participating (120 observations) and not participating in the cooperatives in Truong Long, Tan Thoi, Nhon Ai and Nhon Nghia communes. By using the Probit model, the findings show that there are three statistically significant factors affecting the ability of farm households to participate in the cooperatives at the 1 percent level including land area, distance to market center, and education level. In addition, the PSM model analysis suggests that the average income of cooperative members is significantly higher than that of non-members, about 40.880 million VND/year at the significance level of 1 percent. The empirical results imply that being a cooperative member is a significant contributory factor toward an increase in household income. Based on the research findings, several recommendations to improve the households' income are proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.673-675
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• 2021

Biometric technology is a next-generation information security technology that provides reliability and convenience. As a core technology in the post-corona era, then on-contact biometric access control system is capable of non-face-to-face and automated technology, and is active not only in Korea but also in overseas markets such as the United States, Europe, and the Middle East. There are precautions that must be taken to reflect requirements such as cooperation between companies and approval of the US Food and Drug Admin is tration in developing IoT-based smart device customized sensors and securing H/W systems.

• Journal of Korea Technology Innovation Society
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• v.10 no.3
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• pp.431-457
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• 2007

The main purpose of this study is to analyze the determinants of innovation in the medium core firms that belong to components and materials industry. For this purpose, we introduce the Schumpeterian hypothesis as a theoretical background at first. According to the Schumpeterian hypothesis, large firms in concentrated markets are likely to have more innovative activities. That means, firm site and market structure are the main determinant of innovation. Then, we propose other economic factors that have been considered to have effects on firms' innovative activities in previous studies. Those factors are export, profit, growth rate, R&D expenditure and capital intensity. In order to analyze the determinants of innovation, we estimate whether firm size, market structure, export, profit, growth rate, R&D expenditure and capital intensity affect to the possibility of creating innovation in medium core firms. In order to do this, our study uses survey data from 'Korean Innovation Survey(2005)' conducted by STEPI as well as utilizes the probit model as an analytical method. According to the empirical results, firm size has a positive relationship with innovative activities of medium core firms but market concentration does not. We find the negative correlation between market concentration and innovative activities in this study. Thus, was have to say that we do not fully support the Schumpeterian hypothesis in this case. Among other variables, profit and R&D expenditure are estimated to have positive relationship with innovative activities, while export and capital intensity are estimated to have negative relationship with innovative activities. In case of growth rate, we do not find any significant relationship with innovative activities. In conclusion, larger firm size, higher market competition, more access to the financial market and additional R&D investment would facilitate innovative activities of medium core firms. However, we have to review the relationship between export and innovative activities that has been estimated in this study. While the estimated effect of export on innovative activities can be explained by the own characteristics of medium core firms that produce and supply capital goods to final manufacturer, we have address this issue in the future.

• Cartoon and Animation Studies
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• s.21
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• pp.71-84
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• 2010

The current distribution structure in Korea film industry is in the multiplex chain. As a result, most small or medium-sized theaters have been excluded from the market, and all the multiplex chain have gradually been formed into the vertical integration structure. The strike by multiplex theaters in Chuncheon who did not screen for one month led to the problem of the vertical integration, which resulted in many effects. Particularly, it caused considerable effect on the cultural desire and instigated movie-goers to turn to illegal content. This study surveys the process in which Korean multiplex theaters in vertical integration structure took over the Korean film market, and consequently, small theaters collapsed, and the theaters in vertical integration structure kick out small theaters in horizontal integration structure, and conducts a survey on the effect of the one-month strike by Chuncheon CGV from September 27 to October 30, 2008 in Chuncheon where said processes had completed so as to determine the effect of and impact of the problem of the vertical integration, monopoly structure. When major consumers of the film industry, i.e., people in their 20s, see their access to newly released films limited due to closing of multiplex theaters, they feel the impulse to access illegal contents. If they miss viewing the newly released films, they prefer to view illegal contents or films on recording media rather than visiting theaters showing those films. They are also influenced by timing of film release. Specifically, methods of illegal access to newly released films, permanent accessibility to them via recording media, and timing of film release influence their viewing patterns.