• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1822-1829
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• 2016

DGPS Reference station is established in Korea for improvement of GPS navigation accuracy and needs of integrity. Recently, DGPS stations provide user positioning information on land as well as ocean. However, this paper investigated visibility and interference environment for performance degradation of Chung-ju DGPS reference station. In case of Young-do reference station, visibility and interference environment were satisfied with reference standard. In case of Chung-ju reference station, visibility was satisfied with 7 degree elevation angle. However, interference environment was not satisfied with reference standard of -50dBm. This paper proposed time differential measurement analysis method excluding error of signal noise for analyzing measurement error. Chung-ju reference station measurement analysis result is three times the error than on Young-do in Dec, 2015. In addition, this paper has confirmed measurement performance degradations because of reference station equipment problem. Future study will be carried out performance analysis of 17 DGPS reference station.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.191-200
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• 1995

Although air, water, and noise pollutions have been widely recognized, electromagnetic forces (EMF) hazard has been rarely recognized as a pollution and very little studies has been done in this country. Thus, in this study electromagnetic forces radiated by various home appliances, office machines, and communication equipments were measured and so were several places radiating strong EMF such as subway stations and electric substations. Among the home appliances microwave oven radiates lots of magnetic field and microwaves, and electric mattress does strong magnetic field. In video game room strong magnetic and considerable electric fields were measured. It was observed strong magnetic field inside of electric powered train and very strong magnetic and electric fields on some platforms. Hand-phone and car-phone radiate very hazardous level of microwaves to brain and that they rapidly come into wide use. In this study data base for various electric machines and places radiating strong EMFs were constructed and could be used for future epidemiological studies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1224-1230
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• 2007

Recently, wireless LAN are often applied in home or office because of its various of convenience. Frequency rage of wireless LAN specified by IEEE 802.11a is at 5.2 GHz and IEEE 802.11b is 2.4 GHz. But in offices with wireless LAN devices, reflection of waves against walls, ceilings, floors and desks made of metal creates multipath problems that reduce communication speed and lose data. These problems can be solved by using EM wave absorber. In this paper, we designed and fabricated EM wave absorbers using MnZn-ferrite, sendust, carbon and CPE(Chlorinated Polyethylene). The EM wave absorber with the ratio of MnZn-Ferrite : sendust : CPE=64 : 16 : 20 wt.% has thickness of 3.7 mm and absorption ability more than 17 dB at 2.4 GHz and the EM wave absorber with the ratio of MnZn-ferrite : carbon : CPE=40 : 15 : 45 wt.% has thickness of 3.8 mm and absorption ability more than 23 dB at 5.2 GHz.

• Science of Emotion and Sensibility
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• v.18 no.4
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• pp.75-86
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• 2015

As a part of integrated study for technical communication between consumer and manufacturer of functional clothing, functional clothing consumers were categorized based on their perception of the functional outdoor jacket and the differences in the source of information and use of hang-tag were examined according to the groups. Questionnaire survey was conducted on 472 males and females in their 20s to 60s, who have experience of purchasing functional outdoor jackets. Perception of functional outdoor jackets was classified into four factors ('functionality', 'price', 'experience/knowledge' and 'brand/design') and the respondents were categorized into three groups according to the factors: 'unconversant/brand & design pursuing group', 'conversant/function pursuing group' and 'high-priced products preferring group'. 'Unconversant/brand & design pursuing group' was composed of high rate of office workers and students in their 20s and 30s who use internet most frequently as source of information while 'conversant/function pursuing group' was composed of high rate of professionals in their 40s and 50s who make the most frequent use of information on hang-tag. 'High-priced products preferring group', which has high rate of the elderly in their 60s and housewives, obtain their information mainly from salespersons. 'Unconversant/brand & design pursuing group' was satisfied with functional information more than other two groups and 'conversant/function pursuing group' concerned for the hang-tag and required more explanation of terminology used in hang-tag. The results effectively explained the features of consumer groups and their different responses toward the information of functional outdoor jacket.

• Proceedings of the Korean DIstribution Association Conference
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• 2006.02a
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• pp.43-78
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• 2006

While trust and commitment, essential ingredients of the relationship quality variables, are core mediating variables for the purpose of maintaining the long-term relationship, in the context of the internal political economy of company and the relational performance of its members, there have been limited studies which explore as to how each of the dimensions have affect differently. The basic purpose of this study is to examine the relationship between an automobile manufacturer and its agencies. The main purpose of this study is to examine how each different dimension of trust and commitment on the automobile manufacturer have different mediating effects in the context of internal political economy variables and relational performance perceived by its agents. Another purpose is to investigate the mechanism by which the relational performance of the agencies is improved. An empirical study surveying 115 sales office managers at a leading automobile manufacturer in Korea was conducted. An analysis of the collected data indicates that while internal political economy variables have a positive influence on the agencies' relational performance through the mediating role of trust and commitment, agencies' benevolence on its headquarter has a different influence on the dimensions of commitment. Currently, an automobile manufacturer is advised to implement the relational management philosophy in dealing with its agencies with an hope of innovative orientation for customers. In this sense, this study is a big stride in providing ample implications for the automobile manufacturer in establishing trust and commitment, which are the prerequisite conditions in developing and maintaining a successful long-term relationship with its agencies, and in improving the agency's relational performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.480-488
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• 2018

The development of information and communication technology has been carried out actively in the field of agriculture to generate valuable information from large amounts of data and apply big data technology to utilize it. Crops and their varieties are determined by the influence of the natural environment such as temperature, precipitation, and sunshine hours. This paper derives the climatic factors affecting the production of crops using the garlic growth process and daily meteorological variables. A prediction model was also developed for the production of garlic per unit area. A big data analysis technique considering the growth stage of garlic was used. In the exploratory data analysis process, various agricultural production data, such as the production volume, wholesale market load, and growth data were provided from the National Statistical Office, the Rural Development Administration, and Korea Rural Economic Institute. Various meteorological data, such as AWS, ASOS, and special status data, were collected and utilized from the Korea Meteorological Agency. The correlation analysis process was designed by comparing the prediction power of the models and fitness of models derived from the variable selection, candidate model derivation, model diagnosis, and scenario prediction. Numerous weather factor variables were selected as descriptive variables by factor analysis to reduce the dimensions. Using this method, it was possible to effectively control the multicollinearity and low degree of freedom that can occur in regression analysis and improve the fitness and predictive power of regression analysis.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.123-131
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• 2004

Internet is absolutely contributed to information technology revolution nowadays. Internet services such as voice and data, etc. are provided home or small office via home gateway. The development of communication equipment via home gateway is implemented rapidly, and its product various. This paper presents the design and implementation of the VoIP equipment including the telephone function based on the embedded environment and being connected to the home gateway and the PC because of taking 2-ethernet LAN ports. As developing environment, the STLC1502 developed at ST Microelectronics as single chip solution, VxWorks as RTOS, and C language as coding mechanism are used. The verification of the developed systems for the voice test is carried out for the gatekeeper via Internet. The performance parameter is considered as the call processing capacity measuring the time of the call setup and clearing, and the data processing capacity for the file transfer. As a call setup and clearing is about 95ms, the call processing capacity is about 10 calls per second. The data processing capacity is 5.7Mbps in case of file transfer of server and client environment. Therefore the performance result is satisfied in the aspect of the call processing time and the data transfer time in Internet.

• Journal of Distribution Science
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• v.10 no.10
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• pp.35-43
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• 2012

Purpose - The current analysis has been done in order to verify the difference between consumer attitudes on the distributor's PB products in terms of practical shopping value and attitudes about the product according to its perceived quality. Research design, data, and methodology - The target respondents of this study were those who have bought PB products at large-scale discount stores within the past six months. We asked homemakers, office workers, and students who live in Seoul or Daejon to respond to a questionnaire by filling out self-evaluations, and collected the completed questionnaires. To test the hypothesis, a t-test was carried out by group for 25 percent of the high and low rankings, including a quarter of the total respondents, to verify attitudes toward products and brands, purchase satisfaction, and re-purchase intention according to the practical shopping value and recognized quality of PB products. A variance analysis was conducted to see if there were differences among groups in terms of practical shopping value and perceived quality. Scheffe's back testing was used to identify differences between groups. Results - The result of the investigation of consumer attitudes according to practical shopping value is as follows. First, it was verified that consumer attitudes about PB products increase as practical shopping value increases. Second, there was no significant. Third, it was verified that repurchase intentions for PB products get higher as the practical shopping value of the consumer increases. The following is the result of the investigation of consumer attitudes according to the perceived quality of PB products. First, it was verified that the product attitude improves as the perceived quality of PB products increases. Second, the research confirmed that the brand attitude improves as the perceived quality of PB products increases. Third, consumer satisfaction is higher when the perceived quality of PB products is high. Fourth, this study verified that repurchase intentions for PB products are higher as the perceived quality of the product increases. Finally, the results of identifying differences between groups for perceived quality and shopping value are as follows. It was identified that there were differences in shopping value according to the characteristics of the groups. However, perceived quality does not change according to the characteristics of groups. Conclusions - These results have practical implications for the marketing strategy of PB products in order to satisfy consumer demands and provide a differentiated service by the distributor. In addition, it is suggested that a communication strategy may be necessary to increase brand loyalty and ensure the continual growth and value creation of PB products as symbolic products for distributors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.235-246
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• 2009

The number of industry wireless networks based on IEEE 802.11 WLAN technology deployed in large outdoor work sites, such as freight container terminal, is increasing these days. Wider service coverage, frequent movements of stations and high requirement on service reliability are main characteristics of these networks compared to the conventional IEEE 802.11 networks used in home, office and school. While the importance of these networks Bets higher, we can hardly find previous studies including concrete analysis on these networks based on actual experiments. We carried out several field experiments at a freight container terminal to analyze its IEEE 802.11 network and found out some problematic situations, such as over 50% retransmission rates and frequent disruption of communication link while a station is moving. We explain why these problematic situations happen and suggest some solutions, such as application of mesh technology, smart handoff based on location and movement pattern and adjustment of signal strength and channel allocation. Methods and tools used in the experiments are also detailed in the paper which may be helpful for similar future studies.

• Archives of design research
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• v.14 no.3
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• pp.87-96
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• 2001

If we look at Korea's urbanization since 1960, only the urban communities like buildings have developed, yet the resting places for human itself have been ignored. Many people continuously felt alienated especially after the mechanization and started to demand for better living space. For that reason, it is essential for us to develop the resting places for human among the buildings in urban areas and these resting places could form the basis of new community. We have researched on street furniture and citizen's behavior pattern in resting places through references and internet surfing to propose a design concept for a new resting place and street furniture, Therefore, we would like to design a resting place in urban area considering human, community and environment. As a result, we have designed a resting place where citizens could interact with surrounding environment and let office workers enjoy the nature among the buildings in this resting place. People could always stop by and take some rose by enjoying the surrounding nature. The resting place consists of 5 zones- public square, environmental zone, communication zone, technology zone, and entertainment zone. Each zone has its own design motif to lead systematic street furniture and site planning. The resting place is formed in a specific region which is a prototype of a resting environment in urban areas in the future and it could be reassigned according to its regional condition.