• Journal of KIISE:Databases
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• v.41 no.4
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• pp.209-216
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• 2014

Various characteristics of social network contents such as real-time, people relationship and big data can help to improve personalized recommender systems. Among them, 'people relationship' is a key factor of recommendation, so many personalized recommender systems utilizing it have been proposed. However, existing researches can not reflect personal tendency and are unable to provide precise recommendations in various domains, because they do not consider intimacy among people. In this paper, to solve these problems, we propose PReAmacy, a Personalized Recommendation Algorithm, considering intimacy among users and various characteristics of social network contents. Our experimental results indicate that not only the precision of PReAmacy is higher than that of existing algorithms, but intimacy is of great importance in PReAmacy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.330-334
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• 2017

Container-based virtualization reduces performance overhead compared with other virtualization technologies and guarantees an isolation of each virtual execution environment. So, it is being studied to block access to host resources or container resources for sandboxing in restricted system resource like embedded devices. However, because security threats which are caused by security vulnerabilities of the host OS or the security issues of the host environment exist, the needs of the technology to prevent an illegal accesses and unauthorized behaviors by malware has to be increased. In this paper, we define additional access permissions to access a virtual execution environment newly and control them in kernel space to protect attacks from illegal access and unauthorized behaviors by malware and suggest the Container Access Control to control them. Also, we suggest a way to block a loading of unauthenticated kernel driver to disable the Container Access Control running in host OS by malware. We implement and verify proposed technologies on Linux Kernel.

• The Journal of Korean Institute of Information Technology
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• v.17 no.7
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• pp.1-11
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• 2019

With the development of smartphones and wearable devices, researches related to platforms that collect lifelogs from these devices and the visualization of the lifelog results have also been advanced. However, the existed researches were impossible to collect data from various devices because they depended on a specific device and platform when transmitting or receiving lifelog data. In addition, they do not provide visualized analysis results of specialized lifelogs in specific areas, such as the users' location information. To resolve the problems, this paper analyzes user location information from the lifelog collection platform and develops the interface and visualization tools for lifelog collection. To do this, we define and analyze the requirements of developing the proposed system. Then, based on the analyzed requirements, this paper develops a lifelog visualization tool using various graphs, maps and the RESTful API interface and shows its implemented results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.55-59
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• 1993

Essential oil components and contents were investigated at different growth stages and organs of Schizonepeta tenuifolia Briquet. The content of essential oil different by growth stages and organs and the amount of essential oil at leaf was higher than any other organ. The content of essential oil at leaf and spica were increased by long growth period. The d-menthone and l-pulegone were maj or components of essential oil and contain 51-76% of total essential oil at leaf and spica. In the early stage leaf. l-pulegone was major component of essential oil but d-menthone was major components in the late stage leaf.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.499-501
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• 2008

본 논문은 공진요소를 포함한 고전압 플라이백 컨버터의 설계 절차를 제시하는 것으로써, 고압 플라이백 컨버터 설계 시 기존 플라이백 컨버터의 Power Stage 설계 식을 적용하였을 때 원하는 출력 전압을 얻지 못한다. 고전압을 발생시키기 위한 고전압 플라이백 변압기는 2차 측의 많은 권선수와 높은 전압 때문에 기생 커패시턴스(parasitic capacitance)가 매우 크고, 과도상태에서 컨버터 전류 및 전압의 기생 공진(parasitic resonance)이 심각하게 발생한다. 이러한 공진요소를 고려하여 고전압 플라이백 컨버터의 특성을 해석하고 설계 절차를 제시한다. 이를 통해 고전압 플라이백 컨버터의 소형화 및 경량화를 도모하고, 고압 전원장치의 기술 축적을 위해 연구되었다. 제안된 회로의 동작원리를 설명하고, 타당성을 실험을 통하여 검증한다.

• Spatial Information Research
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• v.11 no.4
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• pp.421-437
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• 2003

In order to calculate the position of parcel boundary points, the area of the Parcel, and the length of the parcel boundary lines using a digitalized cadastral map or maps, the distortion of the map has to be corrected. The correction methods, such as the method of 2D affine transformation using 4 comer points of the edge lines, the method of tessellation into 9 subregions, the method of using the original surveying sheets, and the method of straightening the 4 edge lines, have been developed. In this Paper, the four methods were programed and applied to some sample cadastral maps and the correction accuracies were obtained and analysed. No method could prefectly correct the distortions because the distortions were irregular throughout the maps. However, it is found that tile method of straightening the 4 edge lines is the one which can minimize the distortions when the method is applied after applying the 2D projective transformation on the maps using the 4 comer points of the edges.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.197-203
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• 2014

The liquid jet breakup has been studied in the areas such as aerosols, spray and combustion. The breakup depends on several physical parameters such as the jet velocity, the nozzle inner diameter, and the density ratio of the water to the jet. This paper deals with characteristics of the jet breakup according to the jet velocity and the nozzle diameter. In order to consider only hydrodynamic factors, all the experiments were conducted in non-boiling conditions. The jet behavior in the water pool was observed by high-speed camera and PIV technique. For the condition of the inner diameter of 6.95 mm and the jet velocity of 2.8 m/s, the debris size of 22 mm gave the largest mass fraction, 39%. For higher jet velocity of 3.1 m/s, the debris size of 14 mm gave the largest mass fraction, 36%. For the nozzle with inner diameter of 9.30 mm, the debris size distribution was different. For jet velocity of 2.8 m/s and 3.1 m/s, the debris size with the largest mass fraction was found to be 14 mm. It was identified that the debris size decreased as the diameter or the jet velocity increased.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.1
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• pp.19-32
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• 2001

This paper proposes a local adaptive thresholding method based on a water flow model, in which an image surface is considered as a 3-dimensional (3-D) terrain. To extract characters from backgrounds, we pour water onto the terrain surface. Water flows down to the lower regions of the terrain and fills valleys. Then, the amount of filled water is thresholded, in which the proposed thresholding method is applied to gray level document images consisting of characters and backgrounds. The proposed method based on a water flow model shows the property of locally adaptive thresholding. Computer simulation with synthetic and real document images shows that the proposed method yields effective adaptive thresholding results for binarization of document images.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.519-521
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• 2012

보건의료서비스는 스마트 시대의 도래와 함께 의료와 복지, 안전 등이 복합화 되고 지능화된 스마트헬스(s-Health)의 단계로 진화되고 있으며, 향후 이용자 중심으로 다양한 서비스가 상호 연계되는 고도로 지능화되고 종합화되는 서비스로 지속적인 발전이 예상되고 있다. 따라서 PHR(Personal Health Record)서비스의 활성화를 위해서는 PHR 공동 활용 체계를 구축하기 위한 Open Platform이 필요하다. 본 논문에서는 IHE XDS 프로파일 기반의 진료정보교류 환경에서 PHR 공동 활용 체계 구축을 위하여 Mobile PHR Store를 개발하고 open API 기반 PHR Platform을 제시한다.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.393-396
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• 2009

기존의 웹을 확장한 시맨틱 웹의 등장으로 웹 온톨로지의 구축이 중요시 되고 있다. 이로 인하여 현재 웹 온톨로지의 관리 및 활용을 위한 편집기, 웹 온톨로지 기술언어, 저장소 및 추론 엔진 등 다양한 기술 및 시스템들이 개발되어 웹 온톨로지의 구축이 용이해졌다. 이제는 구축된 웹 온톨로지를 응용 시스템에 활용하기 위한 웹 온톨로지 클래스에 대한 인스턴스를 풍부하게 할 수 있는 웹 온톨로지의 확장에 대한 연구가 요구된다. 웹 온톨로지의 확장을 위해서는 먼저 웹 온톨로지를 보다 정확하게 정의해야 하며 웹 온톨로지를 보다 풍부하게 확장할 수 있는 방법이 개발되어야 한다. 웹 온톨로지의 보다 정확한 정의를 위해서는 표준화 된 공통 개념을 이용하여 웹 온톨로지 스키마를 생성해야하며 이를 기반으로 한 웹 온톨로지 간 상호운용성 향상되어야 한다. 따라서 이 논문에서는 표준화 된 공통 개념을 관리하는 메타데이터 레지스트리(Metadata Registry)를 기반으로 구조화 된 데이터를 이용한 웹 온톨로지의 학습 및 확장 모델을 제안한다. 또한, 제안 모델을 위한 프로토타입을 구현하고 제안 모델의 평가에 대하여 기술한다.