• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.15-22
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• 2008

The cdma2000 1xEV-DO system controls the data rates of mobile terminals based on a binary overload indicator from the base station and a simple probabilistic model. However, this control scheme has difficulty in predicting the future behavior of mobile terminals due to a probabilistic uncertainty and has no reliable means of suppressing the traffic overload, which may result in performance degradation of CDMA systems that have interference-limited capacity. This Paper proposes a new traffic control scheme that controls the data rates of mobile terminals effectively by predicting the future traffic load and adjusting the forward-link control channel. The proposed scheme is analyzed by modeling it as a multi-dimensional Markov process and compared with conventional schemes. The numerical results show that the maximum cell throughput of the proposed scheme is much higher than those of the conventional schemes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.191-198
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• 2015

The purpose of this study is to develope a current variation control system appropriate to the various LED(Light Emitting Diode) lamps using current control system equipped with microcontroller based voltage regulator of power driving circuit. For this, we will suggest a stable control system of current variation to enable a stable power-supply and current-control, consisting of circuit to minimize the affects on the LED forward voltage using variable resistance and compensating resistance. The method of constant current circuit and energy savings using microcontroller based voltage regulator suggested in this study can be applied to various a big capacity LED lamp to minimize the unnecessay heat generation and to control resistace delicately. Ultimately, we expect the results of this study will upgrade the reliability of LED lamp by supplying the current stably.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.1-8
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• 2016

Coding education is an effective convergence type educational tool. While solving problems and designing programs, students can enhance problem solving ability, logical reasoning ability and creative thinking. Researches on coding education are done primarily for elementary school and middle school students. However, researches on college students are lacking. Today, educating college students about coding is in dire need. Although there are efforts to promote the importance of coding education and make it requirements. People find it difficult to find ways to provide training. There is a need for researches on coding as universal education. Therefore, this research proposed educational training using app inventor based on flipped running in order to effectively promote coding education. This study conducted the survey and the personal interview to measure the effectiveness of coding education. It is hoped that, through coding education, students who do not major in coding could combined their knowledge of their major with coding to improve their problem solving ability to solve various problems based on computing knowledge and approach.

• Korean Journal of Construction Engineering and Management
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• v.17 no.6
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• pp.3-12
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• 2016

The purpose of this study is to provide a domestic applicable modular building construction process by benchmarking international best practices. In this study, we derive the risk factors that may occur in performing a modular construction projects and the modular construction management factors through case analysis. In order to effectively respond to risks in performing a modular building projects, we propose the modular building construction process which is separated by a transportation, lifting, assembly steps based on the unit module construction sequence. It is the key to providing management information and guidelines for the design, production, construction participants by reflecting the information for each step in the process. This study would prevent a potential hazard which may occur in the construction process. Consequently, It could result in saving the entire cost of modular construction project as shortening the project schedule and could improve workability of modular construction.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.414.1-414.1
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• 2016

스크린 프린팅법을 이용한 태양전지의 전극은 주로 고가의 은을 사용하기에 태양전지의 저가화에 한계를 가지고 있다. 고효율 결정질 실리콘 태양전지의 원가절감의 문제 해결방안으로 박형 웨이퍼 연구개발이 많은 관심을 받고 있다. 본 연구에서는 은 전극을 대체 할 수 있는 니켈/구리 전극을 사용하였고, 박형 웨이퍼에서도 전극 공정이 가능한 도금법을 사용하여 전극을 형성 하였다. 니켈 전극형성은 광유도 도금법(Light-Induced Plating), 구리 전극형성은 광유도전해도금법(Light-Induced Electro Plating)을 이용하여 실험을 진행 하였다. 니켈 광유도 도금 공정시 공정시간 3 ~ 9분까지 가변하였다. 니켈실리사이드 형성 위해 열처리 공정을 $300{\sim}450^{\circ}C$까지 가변하였고 유지시간 30초 ~ 3분까지 가변하여 실험을 진행하였다. 니켈 도금 수용액의 pH 6 ~ 7.5까지 가변하여 실험하였다. 구리 광유도 전해도금 공정 전류밀도를 $1.6mA/cm^2{\sim}6.4mA/cm^2$까지 가변하여 실험을 진행 후, 전류밀도 $3.2mA/cm^2$로 시간 5 ~ 7분까지 가변하여 실험 하였다. 니켈 도금 공정 시간 5분, 니켈실리사이드 형성 열처리 온도 $350^{\circ}C$, 유지시간 1분에서 DIV(Dark I-V) 분석결과 가장 적은 누설전류를 확인하였다. 니켈 도금액 pH 6.5에서 니켈입자 및 구리입자의 균일성이 좋은 최적의 조건임을 확인하였다. 구리 도금 공정 전류밀도 $3.2mA/cm^2$, 시간 5분에서 TLM(Transmission Line Method) 측정결과 접촉 저항 $0.39{\Omega}$과 접촉 비저항 $12.3{\mu}{\Omega}{\cdot}cm^2$의 저항을 확인하였다. 도금법을 이용하여 전극을 형성함으로써 접촉저항 및 접촉 비저항이 낮고 전극 품질이 향상됨으로서 셀의 전류밀도 $42.49mA/cm^2$를 얻을 수 있었다.

• Journal of Cadastre & Land InformatiX
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• v.45 no.2
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• pp.71-85
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• 2015

Recently, the South Korean government actively opens the public data to encourage people to use it in private sector. It is based on 'Government 3.0' that is the paradigm for government operation. According to this trend, a data platform is required for establishing and commercializing business models that utilizing geospatial data. However, it is currently insufficient to establish the geospatial data system using the text-based public open data. This study constructs a geospatial data supply system using the public data for the purpose of providing and using the public data of spatial reference type efficiently. It improves the accessibility of user and the usability to the public data having location information. Besides, this study suggests that the components of the appliance system that connects the public data from different public institutions for different purposes with producing the geospatial data in the type of a finished product.

• Smart Media Journal
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• v.4 no.2
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• pp.34-45
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• 2015

The illegal copy of Windows software is one of the problems, because Windows is the most popular operating system in the country. The illegal copy can be infringe a software copyright, and software birthmark is one of solutions which is protecting software copyright. Software birthmark is a technique to distinguish software piracy using feature information from software. The type of software birthmark can be differentiated between static birthmark and dynamic birthmark through an extraction method. Static birthmark and dynamic birthmark have strengths and weaknesses. In this paper, we propose similarity measurement technique using dynamic birthmark based on API, and we explain extraction process of dynamic birthmark. In addition, we have verified that the proposed similarity measurement technique meet resilience and credibility through experiment. Furthermore, we saw that proposed measurement technique better than existing measurement technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.942-949
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• 2016

Efficient routing protocols designed for Wireless Sensor Networks (WSN) can be extended and applied to Internet of Things (IoT) data routing, as IoT can be considered to be an extension from WSN. When the size of the data in IoT is often bigger than in conventional WSNs, existing cluster routing protocol such as LEACH may cause high data loss rate due to its incomplete load balancing. We present an enhanced LEACH-based protocol which can minimize the data loss which is an important performance measure in IoT. In our proposed protocol, the base station estimates the location of nodes by the trilateration technique to make sure optimal number of cluster heads and members in a deterministic manner. We evaluate our proposed protocol via computer simulations in terms of data loss rate and average network lifetime.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.208.1-208.1
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• 2015

최근, 차세대 투명 디스플레이 구동소자로서 산화물 반도체를 이용한 Transparent Amorphous Oxide Semiconductor (TAOS) 기술이 큰 주목을 받고 있다. 산화물 반도체는 기존의 a-Si에 비해 우수한 전기적인 특성과 낮은 구동전압 그리고 넓은 밴드 갭으로 인한 투명성의 장점들이 있다. 그리고 낮은 공정 온도에서도 제작이 가능하기 때문에 유리나 플라스틱과 같은 다양한 기판에서도 박막 증착이 가능하다. 하지만 기존의 furnace를 이용한 열처리 방식은 낮은 온도에서 우수한 전기적인 특성을 내기 어려우며, 공정 시간이 길어지는 단점들이 있다. 따라서 본 연구에서는 산화물 반도체중 In-Ga-Zn-O (IGZO)와 In-Sn-O(ITO)를 각각 채널 층과 게이트 전극으로 이용하였다. 또한 마이크로웨이브 열처리 기술을 이용하여 기존의 열처리 방식에 비해 에너지 전달 효율이 높고 짧은 시간동안 저온 공정이 가능하며 우수한 전기적인 특성을 가지는 투명 박막 트랜지스터를 구현 하였다. 본 실험은 glass 기판위에서 진행되었으며, RF sputter를 이용하여 ITO를 150 nm 증착한 후, photo-lithography 공정을 통하여 하부 게이트 전극을 형성하였다. 이후에 RF sputter를 이용하여 SiO2 와 IGZO 를 각각 300, 50 nm 증착하였고, patterning 과정을 통하여 채널 영역을 형성하였다. 또한 소자의 전기적인 특성 향상을 위해 마이크로웨이브 열처리를 1000 Watt로 2 분간 진행 하였고, 비교를 위하여 기존 방식인 furnace 를 이용하여 N2 분위기에서 $400^{\circ}C$로 30분간 진행한 소자도 병행하였다. 그 결과 마이크로웨이브를 통해 열처리한 소자는 공정 온도가 $100^{\circ}C$ 이하로 낮기 때문에 glass 기판에 영향을 주지 않고 기존 furnace 열처리 한 소자보다 전체적으로 전기적인 특성이 우수한 것을 확인 하였다.

• Culinary science and hospitality research
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• v.15 no.4
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• pp.245-258
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• 2009

This study is to theoretically verify the components of job satisfaction and turnover intention of cuisine employees working in the hotel and food service industry and to present some implications for more reasonable and efficient personnel management. Cuisine employees show higher turnover than others do. Change in cuisine employees has an adverse effect on their companies. Additional expenses for hiring and training new employees are needed as well. Consequently, the ways of improving job satisfaction should be sought, since job satisfaction can lower the turnout of the cuisine employees and cut down expenses as well. For the survey, employees working at a hotel located in Daegu were inquired of. Total 254 copies collected and 239 were analyzed for this study(24 was excluded due to the insincere responses). SPSS/WIN 12.0 statistical program was used. The result is that job satisfaction and adequate personnel allotment of the hotel and food industry employees decrease their resignation intention. For efficient management and reduced expenses, plans should be made to increase employees' job satisfaction.