• Journal of Positioning, Navigation, and Timing
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• 제6권3호
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• pp.95-104
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• 2017

Positioning signals transmitted by Global Positioning System (GPS) satellites located at approximately 20,000 km height is very weak. For the reason, GPS signals are vulnerable to intentional jamming and unintentional disturbance. Recently, the number of jamming has been increased significantly all over the world. For the applications where continuous and reliable positioning is required when GPS jammers are activated, other positioning systems are strongly required. In this work, a set of Time Division Multiple Access (TDMA)-based transmitters and receivers utilizing Universal Software Radio Peripheral (USRP) and GNU Radio are designed and implemented. To eliminate the undesirable effects of GPS jamming, a frequency band which does not overlap L band is utilized. To demonstrate the accuracy of the proposed method, an experiment was performed.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.5-8
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• 2019

최근 미세먼지, 황사 등의 환경 문제로 인하여 실내 환경의 쾌적함이 요구되고 있고, 인간에게 가장 쾌적한 실내 환경을 추구하고 있다. 이에 본 연구에서는 실내 온도와 습도 등의 정보를 확인할 수 있게 하기 위하여 모니터링 시스템과 모바일 애플리케이션을 설계하고 구현하였다. 본 연구에서 제안한 시스템을 설계하고 구현하기 위하여 오픈 소스 소프트웨어와 하드웨어 등이 필요하다. 본 연구에서 구현한 시스템에는 블루투스 모듈, 조도 센서, 온습도 센서를 사용하였다. 향후 연구 주제로는 모터를 이용하여 제습기, 온풍기, 선풍기, 가습기 등을 작동하고 실내 환경을 최적화할 수 있는 시스템의 기초 연구가 될 것을 기대한다.

• 기술사
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• 제32권1호
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• pp.122-141
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• 1999

Groupware is a new emerging research field, involving increasing numbers of institutions in the USA, Europe, and Asia such as Korea and Japan, etc., as an interdisciplinary research and development area with a strong computer science component. It grew from fairly unsystematic attempts by various developers to generate software that would increase the competence of people working together. This in turn was partly a response to: failures of and problems inherited from Office Automation and Management Information System ; some sociological intuitions about ways people might work together; and a search for uses of new interfacing, networking, and multi-media technologies. In this paper, groupware that has been configured to meet the needs of groups at work is defined as computer-based systems which support working groups of people engaged in common task in a shared environment. The basic concepts, origin, and historic research of the groupware are described. Specially, groupware relies on the approaches and contributions of many disciplines in computer science as well as sociology that is concerning human, social, and cultural activities. So, nine key disciplines of them upon which successful groupware depends are described briefly. Some state-of-the-art implementations and developments are reviewed through classifying and analyzing the current available groupware applications in the field or market.

• 한국전기전자재료학회논문지
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• 제28권1호
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• pp.64-68
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• 2015

In this paper, LED lighting system is realized by using Bluetooth wireless communications and smartphones. A bluetooth module with a lighting control function is manufactured by miniaturizing a development board of TI company and the volume of LED dimming system as a whole is reduced. And a trial product is materialized by designing a hardware composed of the manufactured bluetooth module, LED down light equipped with degree warm white and cool white, and 2-channel LED driver; and LED dimming software. The materialized trial product is controled in terms of the brightness and color temperature of LED light source using an application of a smartphone. The experiment showed that the users can easily control the intensity of illumination of LED light source by using the scroll bar of the applications of smartphones. In addition, the color temperatures of both warm white and cool white can be controlled, and when the color temperature of the trial product using the manufactured bluetooth module is compared with that of a trial product of TI company, they show the same color temperatures.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권4호
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• pp.249-254
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• 2009

The today's decision making tasks in globalized business and manufacturing become more complex, and ill-defined, and typically multiaspect or multi-discipline due to many influencing factors. The requirement of obtaining fast and reliable decision solutions further complicates the task. Intelligent decision support system (DSS) currently exhibit wide spread applications in business and manufacturing because of its ability to treat ill-structuredness and vagueness associated with complex decision making problems. For multi-dimensional decision problems, generally an optimum single DSS can be developed. However, with an increasing number of influencing dimensions, increasing number of their factors and relationships, complexity of such a system exponentially grows. As a result, software development and maintenance of an optimum DSS becomes cumbersome and is often practically unfeasible for real situations. This paper presents a technically feasible approximation of an optimum DSS through decreasing its complexity by a modular structure. It consists of multiple DSSs, each of which contains the homogenous knowledge's, decision making tools and possibly expertise's pertaining to a certain decision making dimension. Simple, efficient and practical integration mechanism is introduced for integrating the individual DSSs within the proposed overall DSS architecture.

• Journal of Information Technology Applications and Management
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• 제17권2호
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• pp.47-69
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• 2010

Small and Medium Enterprises(SMEs) represent quite a large proportion of the Information Technology (IT) industry as a whole in terms of the sales revenue and the number of employees. And their role has been constantly growing. However, they have suffered from the shortage and turnover of skilled IT personnel. Under the background, this study focuses on how to effectively retain IT personnel in SMEs. Job embeddedness is the newly emerging concept in the turnover research. It is known that job embeddedness predicts turnover better than the traditional attitude variables such as job satisfaction and it can be developed by human resource practices. So, this study empirically investigates the relationship among human resource practices, job embeddedness and turnover intention. The survey results of 193 IT personnel reveal that compensation, technical competency development, recognition and work-life balance practice have statistically significant effects on job embeddedness, and that job embeddedness has a negative influence on turnover intention of IT personnel. Based on these results, the implications for managing turnover issues in IT SMEs are suggested.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제15권3호
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• pp.172-179
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• 2015

Because of the development of computers and high-technology applications, all devices that we use have become more intelligent. In recent years, security and surveillance systems have become more complicated as well. Before new technologies included video surveillance systems, security cameras were used only for recording events as they occurred, and a human had to analyze the recorded data. Nowadays, computers are used for video analytics, and video surveillance systems have become more autonomous and automated. The types of security cameras have also changed, and the market offers different kinds of cameras with integrated software. Even though there is a variety of hardware, their capabilities leave a lot to be desired. Therefore, this drawback is trying to compensate by dint of computer program solutions. Image processing is a very important part of video surveillance and security systems. Capturing an image exactly as it appears in the real world is difficult if not impossible. There is always noise to deal with. This is caused by the graininess of the emulsion, low resolution of the camera sensors, motion blur caused by movements and drag, focus problems, depth-of-field issues, or the imperfect nature of the camera lens. This paper reviews image processing, pattern recognition, and image digitization techniques, which will be useful in security services, to analyze bio-images, for image restoration, and for object classification.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2873-2878
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• 2023

The purpose of this study is to perform radiation monitoring by acquiring gamma images and real-time optical images for ^99mTc vial source using charge couple device (CCD) cameras equipped with the proposed compact gamma camera. The compact gamma camera measures 86×65×78.5 mm³ and weighs 934 g. It is equipped with a metal 3D printed diverging collimator manufactured in a 45 field of view (FOV) to detect the location of the source. The circuit's system uses system-on-chip (SoC) and field-programmable-gate-array (FPGA) to establish a good connection between hardware and software. In detection modules, the photodetector (multi-pixel photon counters) is tiled at 8×8 to expand the activation area and improve sensitivity. The gadolinium aluminium gallium garnet (GAGG) measuring 0.5×0.5×3.5 mm³ was arranged in 38×38 arrays. Intrinsic and extrinsic performance tests such as energy spectrum, uniformity, and system sensitivity for other radioisotopes, and sensitivity evaluation at edges within FOV were conducted. The compact gamma camera can be mounted on unmanned equipment such as drones and robots that require miniaturization and light weight, so a wide range of applications in various fields are possible.

• 한국응용과학기술학회지
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• 제37권1호
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• pp.76-82
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• 2020

Big data analysis in healthcare research seems to be a necessary strategy for the convergence of sports science and technology in the era of the Fourth Industrial Revolution. The purpose of this study is to provide the basic review to secure the diversity of big data and healthcare convergence by discussing the concept, analysis method, and application examples of big data and by exploring the application. Text mining, data mining, opinion mining, process mining, cluster analysis, and social network analysis is currently used. Identifying high-risk factor for a certain condition, determining specific health determinants for diseases, monitoring bio signals, predicting diseases, providing training and treatments, and analyzing healthcare measurements would be possible via big data analysis. As a further work, the big data characteristics provide very appropriate basis to use promising software platforms for development of applications that can handle big data in healthcare and even more in sports science.

• 한국전자파학회논문지
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• 제11권8호
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• pp.1355-1362
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• 2000

Microstrip antennas are attractive for many applications because of their compact size, low profile, and light weight. Recently, the demand for the miniaturization of the personal communication equipment has been increasing along with the proliferation of personal communication systems. Thus, the development of small antenna has been highly demanded. In this paper, a new technique to reduce the overall dimension of a microstrip antenna with a locally non-homogeneous substrate configuration is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band(824~894 MHz) is designed with the proposed technique, and commercialized with low cost, light weight, and small size. Comparison between simulations, based on Agilent Technologies HFSS software, and measurements are provided. The proposed method will be more attractive for a light-weight, small-size, and low-cost microstrip array design. This paper also presents the bandwidth improvement technique for under-coupled microstrip patch antenna with a tuning stub.