• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.26-35
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• 2009

OFDM (Orthogonal Frequency Division Multiplexing) system is robust to frequency selective fading and narrowband interference in high-speed data communications. However, an OFDM signal consists of a number of independently modulated subcarriers and the superposition of these subcarriers causes a problem that can give a large PAPR(Peak-to-Average Power Ratio). Phase rotation method can reduce the PAPR without nonlinear distortion by multiplying phase weighting factors. But computational complexity of searching phase weighting factors is increased exponentially with the number of subblocks and considered phase factor. Therefore, a new method, which can reduce computational complexity and detect phase weighting factors efficiently, should be developed. In this paper, a modeling process is introduced, which apply metaheuristic algerian in phase rotation method and optimize in PTS (Particle Swarm Optimization) scheme. Proposed algorithm can solve the computational complexity and guarantee to reduce PAPR We analyzed the efficiency of the PAPR reduction through a simulation when we applied the proposed method to telecommunication systems.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.13-20
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• 2007

This study was conducted to collect the basic data fo the development ot hydroponic technique and the efficient promotion of water culture. We have also analysed the water culture associated domestic patent application informations searching for on-line internet site with an admission fee (http://www2.wips.co.kr) from the year 1983 to January, 2006. Fifty nine patent applications related to the hydroponics were searched for in this study. Main patent contents applied were as followed in the order of that nineteen applications about the hydroponic equipments by 32.2%, thirteen applications about the materials used in water culture by 22.0%, eleven applications about the composition of nutrient solution by 18.6%, nine applications about the cultural methods by 15.3%, and seven applications about the cultural media by 11.9%. The compositions of nutrient solution and the cultural methods intended for specific crops were increased in number following five applications about tomato plants and four applications about potatoes. Thirty three patents (55.9%) were mainly applied before the year 2000. Main patent contents were the compositions of nutrient solution before the year 2000 in contrast to the cultural methods and substrates after the year 2000.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.131-140
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• 2012

The shortest path search algorithm of navigation is generally based on Dijkstra algorithm and considers only the distance using the weight. Dijkstra algorithm based on the distance mainly ought to perform the 'number of nodes 1' and requires a lot of memory, for it is to start from the starting node and to decide the shortest path for all the nodes. Also, it searches only the same identical path in case of any bottleneck due to an accident nearby, since it is based only on the distance, and hence does not have a system that searches the detour road. In order to solve this problem, this paper considers only the travelling time per road (travelling speed * distance), without applying speed criteria (smoothness, slow speed, stagnation and accident control) or road class (express road, national road and provincial road). This provides an advantage of searching the detour, considering the reality that there are differences in time take for the car to travel on different roads with same distance, due to any accident, stagnation, or repair construction. The suggested algorithm proves that it can help us to reach the destination within the shortest time, making a detour from any congested road (outbreak) on providing an information on traveling time continuously(real-time) even though there is an accident in a particular road.

• Korean Security Journal
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• no.11
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• pp.227-243
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• 2006

In modern society, private securities have developed their capabilities continuously. However, despite the fact that not only security industries have been considerably expanded in quantity, but also plenty of scholars published diverse papers relating to security problems, qualitative growths of private securities have not accomplished fully. Especially, securing the President would not be guaranteed only by PSS(Presidential Security Service). In order to secure the President successfully, it is necessary for all the social parts to strive to protect the President. In this respect, improving private securities, including academic fields, might be critical so as to succeed in securing the President. Without the supports from private securities, there might be lots of security problems in national context. Therefore, this study proposes several policy suggestions for the cooperation among PSS, private security industries and academic fields: (1) Providing a lot of practical knowledge from PSS to college students, (2) Personnel exchange between academic parts and PSS to promote the efficiency of securing the President, (3) Furnishing diverse information and knowledge about security to private securities, (4) Formulating security-searching standards, (5) Expanding educational institutions under PSS.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.665-676
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• 2015

In this case study, we analyzed the processes of STEAM lessons conducted by preservice secondary science teachers. Three preservice science teachers at a college of education in Seoul participated in this study. After the workshop for STEAM education, they planned and practiced STEAM lessons. All of the teaching-learning materials were collected before lessons, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The processes of STEAM lessons were analyzed while focusing on PCK and PDC. Their difficulties, needs, and views on STEAM education were also studied. It was found that they have taken much efforts to reflect the objectives and characteristics of STEAM education, and prepared teaching-learning materials by searching on the internet and arranging creative contents. Their great difficulty was to determine topics for STEAM lessons. While one preservice teacher satisfied with her lesson perceived STEAM education positively, the others perceived that it would be very difficult to practice STEAM lessons in school. For their STEAM lessons to be successful, the workshop needs to include some specific information on grades, proper topics for each grade, ways of making materials, and tips for effective STEAM lessons. In addition, it will be effective if the workshop is carried out after their study on constructivist learning theory and if they experience successful STEAM lessons.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.6
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• pp.185-194
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• 2016

Recently, as the popularization of the mobile and the internet, the need of big data technology using a vast amount of data which contains the information has emerged. Big data technology has been used in various fields but use of the public sector is still insufficient. So, this study applies them. This study explores factors influencing silver industry as keywords, graving has effect on the present as well as future society. Results, five variables are 'silver Industry', 'senior citizen who lives alone', 'aging', 'birth' and 'retirement' were searched, and it was confirmed that they are correlated with one another. Results of analyzing the influence of the other four parameters on "Silver Industry", they have an effect significantly. In addition, it proposed the need of the 'providing living space of senior citizen who lives alone', 'childbirth support policy', 'support to vitalize silver startup senior manpower of technology' as an alternative to develop the silver industry. This study provided the theoretical implications that is exploring factors through a quantitative approach using big data and the practical implication is to suggest an alternative.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.199-204
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• 2013

In this paper, a new system requirement management tool and its application on the Urban Transit Maglev Project were introduced. In most R&D projects on complexity system such as transportation system, Systems Engineering(SE) activities are included on each project, and SE teams are using commercial computer-based tools to perform the SE activities. Even though SE tools help to manage huge data and documents on engineering efficiently, but well-designed functions of SE tools which support SE activities are not sufficiently used on the whole process of system engineering. In order to computer-based SE tools are to be effectively used on project management, most engineers who takes engineering and coordination roles, at least sub-project managers should be familiar to the tool and could be easily use it, but usability of commercial SE tools are very difficult for normal engineers with no experience on SE activities and SE tools. To overcome this difficulty, we developed a new system requirement management tool considering each user's scenario on using engineering tools. The developed tool could not cover whole SE processes, but designed to perform requirement engineering such as system requirements(SRs) management, specification management, traceability management, SRs' verification activity management and so on. All the entities on SR database are inter-connected by pre-recognized traceabilities, so even non-specialists on SE can easily browse the database and find entities concern, and linked information such as interacted entities, legal or engineering constraints, coordination documents, status of development and verification and so on. Also functions for SR verification tools, TPM(Technical Performance Measure) tools, DB searching tools with traceability, and report generation tools are included on the system.

• Journal of Distribution Research
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• v.16 no.5
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• pp.141-169
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• 2011

This study compares the business performances and the socioeconomic and sociopsychological characteristics of franchisees and independent business owners (IBOs). On the basis of extant theoretical arguments and empirical evidences it was expected that franchisees are different from IBOs in these aspects because unlike IBOs they are using franchising as their way of businesses and should satisfy the requirements imposed by franchisors. Analyzed in the current study was a national survey database of 424 franchisees and 5,690 IBOs compiled by the Small Enterprise Development Agency in 2011. As expected, it was found that franchisees were significantly different from IBOs in such traits as financial and managerial capabilities, business experiences, demographic and socio-psychological characteristics, information searching efforts, business performances, and their perceptions of business obstacles. It was also found that the effects of these traits on business performances were quite different between franchisees and IBOs. The findings of the current study provide some meaningful suggestions for government agencies. Given that franchises and IBOs have different traits, their demands for governmental policy should be different, and consequently, it might be argued that government agencies should treat the two groups separately and should increase their efforts to develop appropriate supporting policies for each group. With respect to franchisor's practices for franchisee selection, it is also argued that in order to enhance franchisee performances franchisors need to examine thoroughly the traits of prospect franchisees. This study concludes with discussion of several theoretical and methodological limitations for future research.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.279-299
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• 2013

The problem of choosing the right product that will best fit a consumer's taste and preferences extends to the field of electronic commerce. However, e-commerce has been able to create a technological proxy for the social filtering process, known as online recommender systems (RSs). RSs aid users in filtering products and decisions on matters relating to personal taste. RSs have the potential to support and improve the quality of the decisions consumers make when searching for and selecting products and services online. However, most previous research on RSs has focused on the accuracy of the algorithms, with little emphasis on user interface and perspectives. This study identified transparency and feedback as possible ways to effectively evaluate RSs from the user's perspective. Thus, this research focused on examining and identifying the roles of transparency and feedback in recommender systems and how they affect users' attitudes toward the system. Results of the study showed that both transparency and feedback positively and significantly affected perceived trust, perceived value of the process, and perceived enjoyment. Furthermore, we found that perceived trust, perceived value of the process, and perceived enjoyment positively and directly affected users' intentions to use/reuse a recommender system.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.3
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• pp.69-78
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• 2013

Objectives The purpose of this study was to investigate the effectiveness of the Gongjin-dan (Gongchen-dan, here in after GJD) in order to obtain the evidence for clinical application. Methods The GJD-related articles published from 1990 to 2013 were searched using "Korean Traditional Knowledge Portal", "Oriental Medicine Advanced Searching Integrated System (OASIS)", "Korean Association of Medical Journal Edition (Koreamed)", "Research Information Services (RISS4U)", "Korean Medicine Database (KMbase)", "National Discovery for Science Leader (NDSL)", "PubMed", "China National Knowledge Infrastructure (CNKI)". The search keywords were "Gongjin-dan", "Gongchen-dan". Thirty-nine articles were obtained. After excluding the eighteen article which did not meet inclusion criteria, finally twenty-one articles were included; five clinical articles and sixteen experimental articles. Results In clinical studies, GJD has the various effectiveness in cardiovascular diseases, alcoholic hepatitis, mild dementia, anemia. Also experimental studies related to the GJD show a variety of effects, such as anti-oxidative activity, neuroprotective activity, hepatoprotective activity, anti-inflammatory activity, immunological activity, reproductive recovery activity with fewer side-effects. Conclusions It has been suggested that there are various effects of GJD in treating a wide-range disease. However, in order to put GJD to use for many kinds of diseases in more reasonable ways, it is needed to publish well-design clinical trial based on the variety of results of experimental studies.