• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1184-1193
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• 2010

The upper frequency of international EMC regulations is being expanded above 1 GHz. Radiated emissions above 1 GHz are different from those below 1 GHz that is existing upper regulation frequency, and which have lower field strength and sharper and tilted beam-width, relatively. In this paper, an effective evaluation method to be used above 1 GHz is studied using an offset parabola antenna system having a double-ridged horn antenna as a feed. First, simple model is proposed for calculating antenna factor and field uniformity of the parabola antenna system, and then real radiated emission and radiated susceptibility measurements are performed using a constant noise emitter and the suggested antenna system. The results show that the proposed antenna system has higher gain and power efficiency, and wider field uniformity relative to a conventional double-ridged horn antenna. Therefore, it is confirmed that the proposed system can be effectively used for EMC measurements above 1 GHz.

• Journal of Korea Game Society
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• v.8 no.4
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• pp.29-43
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• 2008

The virtual world is a cyber gaming space where a player interacts with others through their avatars. It is now mainly developed in foreign countries including USA, Canada, and Europe and many experts say that the market capacity of virtual world will be continually expanded in worldwide. The virtual world will mostly be made such that a user accesses the world for free and pays for in-game activities. But it is hardly that we find the effective methodology of payment system for such virtual world due to its' short development history. In the case of Korea, various payment methods of selling in-game assets have been tested in online games. The paper propose an effective revenue model for social virtual world focused on selling in-game assets. The guideline of the proposed revenue model will be expected to contribute creating revenue focused on selling in-game assets, effectively for social virtual world.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.15-20
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• 2015

After the US government declared 3D printing technology a next-generation manufacturing technology, there have been many practical studies conducted to expand 3D printing technology to manufacturing technologies, called AMERICA MAKES. In particular, the Keck Center, located at the University of Texas at El Paso, has studied techniques for easily combing the 3D stacking process with space mobility and expanded these techniques to simultaneous staking techniques for multiple materials. Additionally, it developed convergence manufacturing techniques, such as direct inking techniques, in order to produce a module structure that combines electronic circuits and components, such as CUBESET. However, in these studies, it is impossible to develop a unified system using traditional independent through simple sequencing connections. This is because there are many problems in the integration between the stacking modeling of 3D printers and post-machining, such as thermal deformations, the precision accuracy of 3D printers, and independently driven coordinate problems among process systems. Therefore, in this paper, the integration method is suggested, which combines these 3D printers and subsequent machining process systems through an Internet-based cloud. Additionally, the sequential integrated system of a 3D printer, an NC milling machine, machine vision, and direct inking are realized.

• Journal of Preventive Medicine and Public Health
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• v.45 no.3
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• pp.156-163
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• 2012

Objectives: It is necessary to examine groups carrying out sexually risky behavior because the prevalence of sexually transmitted diseases (STDs) is high among them. In this study, the prevalence of STDs among homosexuals and sexbuying men in South Korea was investigated, along with their sexual risk factors. Methods: Men who have sex with men (MSMs, n=108) were recruited in Seoul and Busan by applying the time location sampling method, while sex-buying men (n=118) were recruited from a john school in Gyeonggi province, the suburbs of Seoul. Dependent variables included past or present infection with syphilis, Chlamydia, gonorrhea, and human immunodeficiency virus. Independent variables included health behavior, social support, sexual behavior, and safe sex. Results: It was found that when the MSMs were non-drunk while having sexual intercourse (odds ratio [OR], 0.132), they showed a higher STD infection rate when they had a higher number of anal sex partners (OR, 5.872), rarely used condoms (OR, 1.980), had lower self-efficacy (OR, 0.229), and were more anxious about becoming infected with an STD (OR, 3.723). However, the men who paid for sex showed high STD infections when they had more sex partners (OR, 2.286) and lower education levels (OR, 3.028). Conclusions: STD infections among the two groups were high when they were engaged with many sex partners and not having protected sex. In other words, there was a gap in risky sex behavior within such groups, which was significantly related to the possibility of developing an STD. Therefore, the preventive intervention against STDs for these groups needs to be expanded to include management of sex behaviors.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.4
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• pp.457-477
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• 2010

Currently, collections with public libraries are evaluated only on the basis of simple data, such as the use volume of collections with individual libraries, and interlibrary lending (ILL) results. To promote the ILL of regional libraries and raise the use of collections, however, the evaluation of collections should be expanded from individual libraries to regional libraries. This study aims to propose user-oriented methods for evaluating the library collections within a regional library system by using four kinds of data: collection, acquisition, circulation, and ILL application data. The results of this study show that the proposed method can reveal the positions of each library within a regional library system, and also the characteristics of a library's collections and users' needs more precisely.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.4
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• pp.303-331
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• 2010

With the full execution of the Comprehensive Library Advancement Plan(2009~2013), related bodies and participants, including national administrative agencies and local government, are increasing and the policy environments are intricately being expanded as well. However, there has been insufficient research on the general aspects of library policies to analyze and evaluate the current circumstances. The objective of this study is to analyze both the problems and suggestions in the areas that need improvements implementing this comprehensive plan. Accordingly, we designed a formative model for evaluating the policy process relating to the comprehensive plan, and then modified and supplemented the developed plan based on the Delphi method utilized by library policy experts. We conducted an empirical evaluation of library policy officials who have established and implemented the comprehensive plan. We then used the evaluation results to assess the effects of the factors regarding the accomplishments reached each policy stage.

• Fire Science and Engineering
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• v.24 no.6
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• pp.139-144
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• 2010

Fire fighting foam is expanded when it mix with many water in mechanical method. It have adaptability, mass production possibility, long-time storage possibility. But foam isn't recommended that it use for extinguish the fire in winter. Because of, expansion ratio is changed according to exterior temperature and environment. In this study, we analysis to effect of expansion according to temperature and develop auto mixing system available for fire engine. As a result of non-standard drug mixture is 3.0% up to 30.08% depending on the temperature of the fire showed that the difference in performance occurs. In addition, analysis of the applicability of automatic mixing system design values and actual experimental data as 0.012% maximum error of the applicability of the system obtained according nataname was judged.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.246-253
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• 2013

Based on the conventional 2-6GHz digital frequency discriminator (DFD) using the phase unwrapping and least-squares techniques, we propose a new 2-18GHz DFD. To compensate for lowered-precision frequency estimation due to the expanded bandwidth, the proposed DFD design employs more delay lines, accordingly accompanying high complexity. Thus, a new computationally efficient frequency estimation algorithm is also presented to overcome such high computational burden. More specifically, the proposed frequency estimation algorithm is basically based on the conventional phase unwrapping technique, along with a new candidates selection for the unwrapped phases under the condition that the phase margin is known. As a result, the computational burden required for the least-squares technique can be reduced. Finally, simulation results are provided to demonstrate the effectiveness of the proposed approach, compared with those of the conventional DFD's.

• Journal of ILASS-Korea
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• v.22 no.3
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• pp.122-128
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• 2017

Currently, the proportion of diesel vehicles in all automobile has grown significantly over the past few years. Air pollutant also grew up and became a social problem. In particular, the issue of NOx emissions caused by NOx high emission in real driving has become a global issue. Despite the fact that the regulatory and reduction project of the new vehicle is actively carried out, there are no existence regulations of In-use diesel vehicle's NOx emission. Therefore, the emission characteristics of the in-use diesel vehicles were investigated to seek ways to reduce NOx emissions in this study. The test targets were used in 237 close inspection of exhaust gases and model year varied from 1996 to 2011. However, the classification of emissions by emission standards differed considerably from NOx emissions. This means that the selection method for early retirement targets should be converted from model year to amount of emissions. If the current early retirement program was applied to the existing system, pre-Euro 3 was 22.530 g/km and Euro 4 was 21.810 g/km to NOx reduction. However, when the vehicle was changed to high emission target vehicle, NOx reduction increase maximum 84.705 kg/yr. According to the study results, an effective reduction in NOx emissions can be achieved if an earlier target in expanded to Euro 4 vehicles.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.1-6
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• 2014

Companies almost don't use an integrated control system using expensive network system in multimedia like TV and DID, despite IP-Broadcasting and communication equipment have expanded rapidly. The proposed integrated TCU(terminal control unit) is a control device that supports TV power On/Off check and remote control, power control reservation function, TV channel change, a variety of interface supports of input/output AC power & Lan port, RS-232C and IR using existing IP network after there is installed the Wake-on -Lan in the set-top box. The TCU can control and monitor 24 hours unlike existing low-cost control system RF method. In existing control equipment markets without expandability and low price, the TCU development including 24 hours monitoring and automatic control functions is expected to secure a wide range of companies.