• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.688-698
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• 2015

This paper presents a modeling and a controller design for a hybrid wind turbine generator, especially with an operating mode of battery energy-storage system and a dumpload that contribute to the frequency control of the system while diesel-synchronous unit is not in operation. The proposed control scheme is based on a robust tracking controller, which takes an account of system uncertainties due to the wind flow and load variations. In order to provide robustness for system uncertainties, the range of operation is partitioned into three operating conditions as sub-models in the controller design. In the simulation study, the proposed robust tracking controller (RTC) is compared with the conventional proportional-integral (PI) controller. Simulation results show that the effectiveness of the RTC against disturbances caused by wind speed and load variation. Thus, better quality of the hybrid wind power system is achieved.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.650-661
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• 2021

The purpose of this study was to compare and analyze the importance and satisfaction of consumer selective attributes by home meal replacement (HMR) types using local ingredients. This study was conducted from December 4 to December 8, 2020. A total of 380 responses organized according to preferred types of HMR (100 for Ready to Eat (RTE), 92 for Ready to Heat (RTH), 88 for Ready to Cook (RTC), 100 for Ready to Prepared (RTP) were used for the final analysis. Statistical analysis was conducted by descriptive analysis, paired t-test, and importance-satisfaction analysis by HMR type. Findings of this study showed significant differences in consumer selective attributes by HMR type. RTE and RTC need to improve quality while RTH needs to improve quality and packaging. Notable selective attributes were quality, packaging, and information. They were located in different quadrants of each HMR type. All other attributes appeared in the same quadrant. Further research is needed to determine differences in quality, packaging, and information for each HMR type. Results of this study provide basic data for developing products and marketing strategies for each type of HMR products using local ingredients.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.54-61
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• 2020

For operating military aircraft, military certificate of airworthiness (MCA) must be obtained from military authority. Among procedures of general airworthiness certification, there is a military type certification process that aircraft design complies with military airworthiness certification criteria. The Surion is the first military rotorcraft which has obtained military type certificate, production validation and airworthiness certificate in Korea, and the Surion derivatives for special mission are being operated for government services. Based on Aviation Safety Act, in order to operate the Surion derivatives (military aircraft) for special purpose (such as emergency patient transportation and firefighting), the issuance of special airworthiness certificates was needed from civil airworthiness authority, and the restricted category type certification (RTC) is one of design approvals for special airworthiness certification to be streamlined. This study discussed the procedures for acquiring RTC for special purpose operation of the Surion derivatives classified as military derived aircraft, and suggested procedural ideas to improve Korean RTC system.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.94-104
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• 2020

Currently media consumption over fixed/mobile Internet is mostly conducted by adaptive media streaming technology such as DASH (Dynamic Adaptive Streaming over HTTP), which is an ISO/IEC MPEG (Moving Picture Experts Group) standard, or some other technologies similar to DASH. All these heavily depend on the HTTP caches that ISPs (Internet Service Providers) are obliged to provide sufficiently to make sure fast enough Web services. As a result, as the number of media streaming users increases, ISPs' burden for HTTP cache has been greatly increased rather than CDN (Content Delivery Network) providers' server burden. Hence ISPs charge traffic cost to CDN providers to compensate for the increased cost of HTTP caches. Recently in order to reduce the traffic cost of CDN providers, P2P (Peer-to-Peer)-assisted DASH system was proposed and a peer selection algorithm that maximally reduces CDN provides' traffic cost was investigated for this system. This algorithm, however, tends to concentrate the burden upon the selected peer. This paper proposes a new peer selection algorithm that distributes the burden among multiple peers while maintaining the proper reduction level of the CDN providers' cost. Through implementation of the new algorithm in a Web-based media streaming system using WebRTC (Web Real-Time Communication) standard APIs, it demonstrates its effectiveness with experimental results.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.43-46
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• 1991

Nd-Fe-B Permanent Magnet, which is recently more used, has some advantages in comparison with other permanent magnet. However, for the Nd-Fe-B has higher RTC(reversible temperature coefficient), property of the Nd-Fe-B magnet is changed by temperature rise. In this paper temperature rise of a disc type motor is calculated using a heat source network method.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.151-157
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• 1993

본 연구에서는 산.학.연 협동을 통해 기술실용화와 중소기업창업을 촉진하는 효과적인 추진방법의 하나로, 대학캠퍼스나 인근지역에 "기술창업.개발센터"(Technology Business Development Center: TBDC)를 설립하는 방안을 제시하고, 구체적인 기술창업.개발센터의 개념과 체계, 설립운영방안, 우리나라에서의 효과적인 추진전략을 제시한다. 특히 국가적 차원에서 TBDC를 지방대학들을 중심으로 한 지역기술개발센터(Regional Technology Center:RTC)의 형태로 전국 각 지역에 설립하여 육성하되, 공개경쟁을 통해 선별적으로 TBDC를 지정할 것을 제의한다. 아울러 정부의 TBDC지원유형과 TBDC의 단계별 육성방안도 제시한다.성방안도 제시한다.

• Journal of IKEEE
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• v.24 no.1
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• pp.293-301
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• 2020

Consultation with the patient and doctor is very important in the examination. However, if the consultation cannot be done directly, such as corona virus, it is difficult for the doctor to determine the patient's condition more accurately. Recently, an image counseling system has been developed based on the Internet, but in the case of heart disease, remote medical counseling cannot be performed because it is not possible to stethoscope the heart sounds remotely. In order to solve this problem, it is necessary to develop an interactive mobile robot capable of remote medical consultation, and a doctor and a patient should be able to set a planting sound during consultation and transmit it in real time. In this paper, we developed a robot that can remotely control a medical counseling robot to move to a hospital room where patients are hospitalized, and to consult a patient in the room remotely from a doctor's office. A remote medical imaging stethoscope system for real-time heart sound transmission is presented. The proposed system is a kind of P2P communication that transmits video information, audio information, and control signal independently through webRTC platform, so that there is no data loss. Consults and sees doctors in real time and finds it more effective than traditional methods for patient security. The system implemented in this paper will be able to perform remote medical care in the place where the spread of diseases between humans like the recent corona 19 as well as the remote medical care of heart disease patients in the future.

• Journal of the Korean Dietetic Association
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• v.26 no.2
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• pp.116-125
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• 2020

The purpose of this study was to assess the sugars contents of home meal replacement (HMR) products currently sold in Korea. This study surveyed and examined the sugars contents in 835 popular HMRs (294 ready-to-eat foods; RTE, 499 ready-to-cook foods; RTC, 42 fresh-cut vegetables; FCV) through the nutrition labels. The average price, weight and energy content of 835 HMR products were 3,917.5 Korean won, 336.0 g, and 522.7 kcal, respectively. The sugars content per product was significantly higher in the RTCs (13.4 g) and RTEs (10.3 g) than that in the FCVs (4.2 g) (P<0.001), and the percentage of energy from sugars was 9.7% for the RTEs, 10.2% for the RTCs, and 8.7% for the FCVs without any significant difference. The sugars contents of 9 RTE types were in the order of side dishes (34.3 g), sunsik (22.5 g) and hamburgers (12.1 g) per package. The percentage of energy from sugars was highest in side dishes (28.1%), followed by kimchi (24.9%), sunsik (17.2%), and hamburgers (10.6%). Among 14 RTC types, the sugars contents were in the order of hot dogs (52.9 g), tteokbokki (30.4 g) and noodles (21.2 g) per package. The percentage of energy from sugars was the highest at 22.9% for sauces, followed by side dishes (17.3%), porridges (14.4%), instant stews (14.3%), and hot dogs (13.1%). Strategies and practices are needed to reduce the sugars contents of HMR producers and the sugars intakes of HMR consumers.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.411-422
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• 2017

Current policies for sharing bandwidth increase average throughput and improve utilization of the bandwidth in the local network. However, with these policies, a central administer, which is responsible for allocating bandwidth to each network flow, cannot allocate resources based on user characteristics. Thus, it leads to unfair bandwidth allocation because it does not guarantee services based on user characteristics. Therefore, we propose a novel negotiation method to share the bandwidth in a limited bandwidth network, in which, a user negotiates with other users to gain more resource. Ideally, we use a fuzzy system to infer and determine whether a device will request bandwidth or not based on the current usage of the given device. We conduct two experiments consisting of a video streaming simulation in OPNET and a real-time video streaming in WebRTC. The results of the experiment indicate that the proposed method can flexibly share the bandwidth utilization based on user's requirement in the network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.889-895
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• 2019

It is not easy to keep time promises in the complex daily lives. Especially, the increase in the number of vehicles causes traffic congestion in commuting time, which results in the delayed arrival and varies greatly depending on the weather conditions. In this paper, proposed is a smart alarm clock that automatically adjusts the alarm time according to weather conditions and suggests ways to deal with traffic congestion. The proposed smart alarm clock is designed to operate the functions of a normal alarm clock using touch functionality. In addition, it is designed to find weather information using open API and to automatically change alarm time to prepare for expected time delay. The proposed design was implemented based on Arduino Mega2560 and a touch TFT-LCD. WiFi module for internet connection, RTC module for clock function and MP3 player module for alarm sound playback were used together. The proposed design has been filed as a patent and is currently under review.