• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.13-21
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• 2016

In this paper we are trying to explain the effect of temperature on polymer membrane exchange water electrolysis (PEMWE) and polymer membrane exchange fuel cell (PEMFC) simultaneously. A comprehensive studying approach is proposed and applied to a 50Watt PEM fuel cell system in the laboratory. The monitoring process is carried out through wireless LoRa node and gateway network concept. In this experiment, temperature sensor measure the temperature level of electrolyzer, fuel cell stack and $H_2$ storage tank and transmitted the measured value of data to the management control unit (MCU) through the individual node and gateway of each PEMWE and PEMFC. In MCU we can monitor the temperature and its effect on the performance of the fuel cell system and control it to keep the lower heating value to increase the efficiency of the fuel cell system. And we also proposed a mathematical model and operation algorithm for PEMWE and PEMFC. In this model, PEMWE gives higher efficiency at lower heating level where as PEMFC gives higher efficiency at higher heating value. In order to increase the performance of the fuel cell system, we are going to monitor, communicate and control the temperature and pressure of PEMWE and PEMFC by installing these systems in a building of university which is located in the southern part of Korea.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.69-80
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• 2015

The Purpose of this study is to establish efficient and balanced development and to make transparent marketing system, environment which is to protect small business, consumer's. This Goal of this study is that focus on development of regional and national economy. Especially, to protect small businessmen, to reserve consumer's buying choice. First of all, to examine causes of distribution maintenance and to will be analysed legal controversy of big distributive markets since local autonomy business limits. It is this study that concentrate on big distributive mart shutdown of business hours, Problems and Countermeasures. The main focus of in this study is as follows: First, to examine the ruling of the court that protest and accept of business hour in big distributive mart' problem and regulation, Second, to understand each of the judgement and problems of distributive shutdown systems, Third, to suggest the good distributive business trade act and the possible collaboration with focus on small and big mart System in Korea. This paper to analyze case of conflict and focus on establishment of transparent distribution since business limits.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.579-586
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• 2018

Short-term prediction of travel speed has been widely studied using data-driven non-parametric techniques. There is, however, a lack of research on the prediction aimed at urban areas due to their complex dynamics stemming from traffic signals and intersections. The purpose of this study is to develop a hybrid approach combining ensemble empirical mode decomposition (EEMD) and artificial neural network (ANN) for predicting urban travel speed. The EEMD decomposes the time-series data of travel speed into intrinsic mode functions (IMFs) and residue. The decomposed IMFs represent local characteristics of time-scale components and they are predicted using an ANN, respectively. The IMFs can be predicted more accurately than their original travel speed since they mitigate the complexity of the original data such as non-linearity, non-stationarity, and oscillation. The predicted IMFs are summed up to represent the predicted travel speed. To evaluate the proposed method, the travel speed data from the dedicated short range communication (DSRC) in Daegu City are used. Performance evaluations are conducted targeting on the links that are particularly hard to predict. The results show the developed model has the mean absolute error rate of 10.41% in the normal condition and 25.35% in the break down for the 15-min-ahead prediction, respectively, and it outperforms the simple ANN model. The developed model contributes to the provision of the reliable traffic information in urban transportation management systems.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.1
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• pp.47-56
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• 2012

The main goal of this study is to investigate the importance of trust as a mediator between shopping experience and shopping value. Previous studies on utilitarian shopping value and hedonic shopping value have focused on the antecedents and outcomes of those shopping values. Also, although the role of trust has been studied a lot in the series of studies on online shopping mall, most of them focus on the relationship with intention to shop or use and there are few studies on the mechanism in which consumers get to have shopping value. This study tries to see how trust can boost utilitarian shopping value and hedonic shopping value which can lead to consumer's loyalty to the shopping mall. A structural equation model is proposed and examined through a survey research to investigate the role of trust in forming perceived shopping value. One model included the trust variable as a mediator and the other excluded it. The comparison of R2 verified that the first model had a better fit. The results of the study show that the level of experience has a significant impact on both utilitarian and hedonic shopping values in the case of the model without the mediator. But experience has an insignificant or a partially significant effect on utilitarian and hedonic shopping values when trust mediates experience and shopping values. Finally, the implications and limitations are further discussed.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.17-23
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• 2013

BACKGROUND: Today, environmentally friendly farming has become an important feature of agricultural policy. It promotes or sustains farming systems which protect and enhance the environment. This study was conducted to compare benthic invertebrate communities in an organic and a conventional paddy field in South Korea. METHODS AND RESULTS: Benthic invertebrates were collected at 11 regions of a rice paddy from June to August, 2009, 2010 and 2011. These comparisons undertaken using a community assessment approaches such as the number of individuals and species and community composition. Generally, the larger number of individuals and species of benthic invertebrates was observed in an organic paddy than in a conventional paddy field. Organic paddy fields could supported the wider range of species and abundance in aquatic invertebrates comparing to conventional paddy fields. Carrying capacity to support larger numbers of invertebrates also tends to be higher in organic paddy than in conventional paddy field. Specially, organic farming regions surrounded by forests were high quality habitat for benthic invertebrates than other surrounded regions such as grassland. CONCLUSION(S): We concluded that organic farming was more advantaged to benthic invertebrates than conventional farming. In order to improve biodiversity in rice paddy field, farming regimes without agricultural chemicals are recommended. The effect of organic management on biodiversity and abundance of benthic invertebrates could be maximized across highland farmland.

• Journal of Environmental Impact Assessment
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• v.17 no.2
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• pp.113-124
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• 2008

A worldwide trend of permitting system for industrial installation to achieve a high level of protection of the environment has been moved from single media to multimedia in approach. The Council of the European Community issued the Directive 96/61/EC, the IPPC Directive, concerning integrated pollution prevention and control in 1996. The IPPC Directive is one of the most ambitious legal measures that the European Union (EU) has initiated with a view to applying the prevention principle for industrial activities. The IPPC aims to achieve the integrated prevention and reduction of environmental pollution emitted by those industrial installations with a higher potential of emissions to the environment. Organization for Economic Cooperation and Development (OECD) recommended on Environmental Performance Reviews of Korea in 2006 that IPPC permitting concept should be considered for large stationary sources at the national and regional levels. Any Korean law doesn't provide for integrated pollution control with a single process covering all pollution from economic activities. However, one exception might be the "environmentally-friendly companies" certification scheme, introduced in 1995, in which participants agree to meet targets beyond the legal emission limit values in exchange for government technical and financial support to operate environmental management systems. The other exception might be Environmental impact assessment (EIA) of projects, in 1977, which has been strengthened and reinforced to be more preventive through development of the prior environmental review system (PERS) in 1999. The aim of this work is to introduce the contents of IPPC Directive at the viewpoint of Korea policy and to survey the integrated approaching concept of Environmentally-Friendly Companies (EFC) Certification Scheme and EIA policy of Korea. The study will be helpful in the future to prepare the infrastructure of integrated permitting system and to enforce the integrated permit which the authorities of local government issues on industrial activities. It can be said that the data calculated through both EFC Certification Scheme and EIA will be discussed as worthful information to determine Korean BAT reference notes for integrated permitting process.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.910-918
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• 2010

In recent years, riparian buffer system has been known as one of the effective best management practices. However, establishment of riparian buffer system in aspect of plant species and its position in the riparian buffer zone has not been investigated due to lack of efficient evaluation method for the analysis of water quality improvement with established riparian buffer system. To solve this problem, the SWAT-REMM prototype was developed by the researchers in Canada. But, SWAT-REMM model can not consider the $NO_3-N$ load into riparian buffer system through subsurface flow. Thus to solved this problem, Fortran code of SWAT-REMM model was modified. This modified SWAT-REMM system was applied to the Bonggok watershed. Three riparian buffer scenarios, 15 m, 10 m, 5 m width for tree and grass, were made to evaluate the effects of riparian buffer system on water quality improvement. Reduction efficiency of T-N by riparian buffer system of 15 m wide was the greatest (6 ~ 37%, depending on subwatershed characteristics) among 3 scenarios. It indicates that the reduction efficiency of T-N load has increasing-tendency, as buffer width increasing. The results obtained from the analysis showed that wide buffer zones are found to be more effective in reducing non-point pollutant than narrow buffer zones in the riparian buffer zone system. Hence, the SWAT-REMM model could be efficiently used for evaluation and design the most effective riparian buffer systems to reduce pollutant loads to the watershed although many limitations still exist in SWAT-REMM model.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.240-248
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• 2005

To implement a globally harmonized system of classification and labeling of chemicals (GHS) in Korea, an interminsterial GHS working group involving 6 ministries established an expert working group composed of 7 experts from relevant organizations and one private consultant to prepare an officialKorean GHS version by March, 2005. As such, the translation and review of the official Korean GHS version, including annexes, started in October, 2004 and was completed on March 15, 2005. The official Korean GHS version has now been posted on the websites of the relevant ministries and organizations to solicit public opinions. The official Korean GHS version will be finalized after a public hearing scheduled forMay, 2005. Collaborative efforts as regards implementing and disseminating the GHS in Korea will be continued to avoid any confusion or duplication and for effective use of resources. The globally harmonized system of classifying and labeling chemicals (GHS) was originally adopted in 1992 at the United Nations Conference on Environment and Development (UNCED), as subsequently reflected in Agenda 21 chapter 19. The work was coordinated and managed under the auspices of the Interorganization Programme for the Sound Management of Chemicals(IOMC) Coordinating Group for the Harmonization of Chemical Classification Systems (UNCEGHS). The technical focal points for completing the work were the International Labour Organization (ILO); Organization for Economic Cooperation and Development (OECD); and United Nations Economic and Social Council's Subcommittee of Experts on the Transport of Dangerous Goods (UNSCETDG). The work was finalized in October 2002, and the World Summit on Sustainable Development in Johannesburg on 4 September 2002 encouraged countries to implement the new GHS as soon as possible with a view to having the system fully operational by 2008 (UN, 2003). Implementation has already started with pilot countries introducing the system to their national practices in different regions of the world. The GHS text, called the purple book, becameavailable as a W publication in early 2003. The GHS text, called the purple book, becameavailable as a UN publication in early 2003. The GHS system will be kept dynamic, and regularly revised and made more efficient as experience is gained in its implementation. While national or regional governments are the primary audiences for this document, it also contains sufficient context and guidance for those in industry who will ultimately be implementing the national requirements that will be introduced (UN, 2003). The Japanese government published their official Japanese GHS version, the first in Asia, in April 2004 after starting work in January 2003 based on an interministerial chemical coordination committee involving 7 ministries, including the Ministry of Foreign Affairs, Ministry of Internal Affairs and Communications, Ministry of Health, Labour, and Welfare, Ministry of Agriculture, Forestry and Fisheries, Ministry of Economy, Trade and Industry, Ministry of Land, Infrastructure, and Transport, and Ministry of Environment (MOE, 2004). Accordingly, similar to the Japanese GHS efforts, this paper presents the interministerial efforts involved in publishing the official Korean GHS version.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.981-986
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• 2020

The Internet of Things refers to a space-of-things connection network configured to allow things with built-in sensors and communication functions to interact with people and other things, regardless of the restriction of place or time.IoT is a network developed for the purpose of services for human convenience, but the scope of its use is expanding across industries such as power transmission, energy management, and factory automation. However, the communication protocol of IoT, MQTT, is a lightweight message transmission protocol based on the push technology and has a security vulnerability, and this suggests that there are risks such as personal information infringement or industrial information leakage. To solve this problem, we designed a synchronous MQTT security channel that creates a secure channel by using the characteristic that different chaotic dynamical systems are synchronized with arbitrary values in the lightweight message transmission MQTT protocol. The communication channel we designed is a method of transmitting information to the noise channel by using characteristics such as random number similarity of chaotic signals, sensitivity to initial value, and reproducibility of signals. The encryption method synchronized with the proposed key value is a method optimized for the lightweight message transmission protocol, and if applied to the MQTT of IoT, it is believed to be effective in creating a secure channel.

• Journal of Nutrition and Health
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• v.53 no.2
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• pp.129-140
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• 2020

Purpose: Although the importance of life satisfaction in patients with chronic diseases has been emphasized, limited studies have been performed on the health-related quality of life (HRQoL) among elderly patients with chronic diseases. This study examined the HRQoL among Korean patients with diabetes aged 65 years or older. Methods: This study used data from the Korea National Health and Nutrition Examination Survey 2008-2016. The analysis included data of 2,353 elderly patients with diabetes aged 65 years or older who were aware that they had type 2 diabetes. Each participant was categorized into one of three age groups (65-69 years, 70-74 years, and ≥ 75 years). The EuroQol-5 Dimensions (EQ-5D) scale was computed to estimate the HRQoL. Multivariate linear regression analysis was used to compare the demographic characteristics, lifestyle characteristics, nutrient intake, and EQ-5D scores between the age groups. Results: The intake levels of most nutrients were similar in the three age groups, but the total energy intake levels were significantly lower, and the sodium intake levels were significantly higher in the older age groups (p < 0.001). In addition, all items of the EQ-5D index, except for anxiety/depression, tended to decrease with age. In particular, the oldest age group (≥ 75 years) showed significantly lower levels on most items and the EQ-5D index than those in the other age groups (p < 0.001). Conclusion: Elderly patients with type 2 diabetes may have low levels of life satisfaction, which worsens with increasing age. Therefore, it is important to develop and manage personalized guidelines and medical systems so that elderly patients have a higher quality of life for the remainder of their lives. The results of this study are expected to be used as basic data for the systematic management of diabetes in elderly Korean patients.