• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.1
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• pp.7-15
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• 2020

It is a general phenomenon for manufacturers to provide vertically differentiated product line for more profit through improved market coverage. For such manufacturers, the compatibility between vertically differentiated products is an important decision issue. Some manufacturers provide full compatibility between high and low version products, whereas some provide only downward compatibility for the purpose of recommending high version product. In this study, the two representative compatibility strategies, full or downward, between vertically differentiated products produced by a single manufacturer are analyzed, especially under network externality and in the viewpoint of profit maximization. To do this we used a market model which captures the basic essence of vertical differentiation and network externality. Based on the proposed market model, the profit maximizing solutions are derived and numerically analyzed. The results can be summarized as follows : (1) Regardless of compatibility strategy, under network externality, vertical differentiation is always advantageous in terms of profit. (2) The full compatibility strategy is shown to be the most advantageous in terms of profit. In addition, it is necessary to make quality difference between differentiated products as wide as possible to maximize profit. (3) To gradually drive low version product out of the market and shift the weight pendulum of market to high version product, it is shown that the downward compatibility strategy is essential. Unlike intuition, however, it is also shown that in order to drive low version product out of market, it is necessary to raise the quality of the low version product rather than to lower it.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1275-1276
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• 2015

Full wave electromagnetic simulation or fabricated models of an antenna are used to predict its radiation characteristics. In this work estimation of radiated power of an antenna based on its electrical model is presented. The computed radiated power using the electrical model have good agreement with the radiated power results obtained through the full wave electromagnetic simulation of the antenna model. The presented approach offers the advantage of saving of computation time of the full wave EM simulation.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.71-88
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• 2007

This study investigates the factors that influence the user's (postal workers') satisfaction with using PDAs in the Korea Postal Services. This study is concerned about the success of IS when employees are mandated to use IS to increase their productivity. The factors examined in this study include independent variables (information quality and system quality), dependent variables (perceived usefulness and user satisfaction), and mediator (compatibility with work). All these factors were found significant for causal relations. We especially notice the role of compatibility with work as full mediator.

• Journal of Auto-vehicle Safety Association
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• v.9 no.1
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• pp.13-18
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• 2017

In recent years, NCAP regulations of many countries have induced automaker to improve the vehicle crashworthiness. But, the current NCAP regulations don't cover all types of traffic accidents. And rapid-increasing market share of compact cars and SUVs has brought for both consumer and automaker to pay more attention on crash compatibility. So, many countries have tried to develop the new crash test mode and update the present crash test mode. Especially, Euro NCAP has been developing a new impact protocol of the car-to-car frontal offset impact including the crash compatibility assessment. There are plans to introduce this new protocol in 2020, and it will be replaced the current Euro NCAP frontal offset impact. The test dummy in the front seats of this new test mode will be changed from 50% Hybrid-III male to 50% THOR male. This paper will address the vehicle responses, the occupant responses and the vehicle compatibility performance from a full vehicle crash test using the new car-to-car frontal offset test protocol of Euro NCAP.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.101-106
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• 1997

Palplus system is a new European 16:9 wide screen TV format which has a full compatibility with standard PAL and the system has a advantage of improving picture quality by the reduction of cross color and cross luminance as well as making use of the full horizontal luminance bandwidth of the PAL system. We implemented European 16:9 PALplus Digital decoder(625/50/2:1) system using SVP(Serial Video Processor) IC and discrete helper demodulator.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.37-48
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• 2011

Synthetic Aperture Radar(SAR) is a powerful and well established microwave remote sensing technique which enables high resolution measurement of Earth surface independent of weather conditions and sunlight illumination. KARI has been developing the first Korea SAR satellite which is scheduled to be launched in this year. The SAR satellite mainly consists of the bus platform and SAR payload. Most of all, the RF compatible design during the design phase and the verification of the RF compatibility during the testing phase is very important procedure for the in-orbit performance guarantee because the SAR payload radiates high power through the SAR antenna. In this study, the SAR satellite design criteria and verification procedure for the RF compatibility are described. In addition, this paper describes the RF full radiation testing (RF auto-compatibility testing) for the verification of the RF performance robustness, the testing configuration, and the test results.

• Korea journal of population studies
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• v.34 no.3
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• pp.179-209
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• 2011

This study explored the relationships among such variables as work-family compatibility, gender attitude, reasons for low birth rate, and education level, using a sample of 2,678 from the '2009 National Survey for Marriage and Birth Trend'. The purpose of this study was to identify the ideas about how to support married couples' work-family balance, and how to change gender attitude to promote childbirth. The results are as follows. The type of ideal work-family balance was different by education level, but not by gender. Low level of education was associated with choice of the full time work without a child. Male singles, compared to female singles, preferred the role of a man as a bread winner, and a woman as a house worker. Female singles had the higher level of hope for husband's capability of caring children. This trend was intensified by choice of the full time work with 2 children. Singles who prefer working as a full time worker with 2 children worried more about low birth rate in Korea than singles who prefer working as a part time worker with one or two children. The most frequently cited reason for low birth rate was 'high cost of both child care and education'. The next was 'difficulty in buying a residence, followed by 'increase in the number of career woman'. Female singles who want to work full time with 2 or more children worried more about the burden of child caring and education than male singles. Implications and suggestions were provided based on the results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.479-484
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• 2018

This paper describes domestic technical standard of Photovoltaic(PV) PCS(Power Conditioning Systems)-Characteristics of the utility interface. This standard tests utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1)voltage, current and frequency, 2)normal voltage operating range, 3)DC injection, 4)normal frequency operating range, 5)harmonics and 6)waveform distortion, 7)power factor of PV inverter. Therefore in this paper each test item of domestic technical standard is studied and analyzed and finally full tested by PV inverter performance function.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.90-95
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• 2015

This paper describes IEC 61727 standard of Photovoltaic (PV) systems -Characteristics of the utility interface. IEC 61727 standard tests include utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1) voltage, current and frequency, 2) normal voltage operating range, 3) flicker, 4) DC injection, 5) normal frequency operating range, 6) harmonics and 7) waveform distortion, 8) power factor of PV inverter. Also personnel safety and equipment protection part includes test items 1)loss of utility voltage, 2)over/under voltage and frequency, 3)Islanding protection, 4)response to utility recovery, 5)earthing, 6)short circuit protection, 7)Isolation and switching of PV inverter. In this paper, each item of IEC 61727 standard test is studied and analyzed and finally full tested by PV inverter performance function.

• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.199-207
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• 2013

Meeting electromagnetic compatibility (EMC) requirements can be a significant challenge for engineers designing today's electronic devices. Traditional approaches rely heavily on EMC design rules. Unfortunately, these design rules aren't based on the specific EMC requirements for a particular device, and they don't usually take into account the specific function of the circuits or the many design details that will ultimately determine whether the device is compliant. This paper describes a design methodology that relates design decisions to the product's EMC requirements. The goal of performance-based EMC design is to ensure that electronic designs meet EMC requirements the first time the product is tested. More work needs to be done before this concept reaches its full potential, but electronic system designers can already derive significant benefit by applying this approach to products currently under development.