디지털방사선촬영술을 이용한 인접면 치아우식증 진단에 관한 실험적 연구

권기정,황의환,이상래,Kwon Ki Jeong,Hwang Eui-Hwan,Lee Sang Rae 대한영상치의학회 1994 Imaging Science in Dentistry Vol.24 No.1

The purposes of this study were clinical comparison and evaluation between digital radiography and conventional radiography for the detection of artificial interproximal caries. Four freshly extracted, unrestored posterior teeth were obtained and caries was simulated by drilling semicircled defects with variable size at the interproximal surface of each tooth. The experiments were performed with IBM-PC/32 bit-DX compatible, video camera(VM-S8200, Hitachi Co., Japan), and color monitor(Multisync 3D, NEC, Japan). Sylvia Image Capture Board for the ADC(analog to digital converter) was used, and spatial resolution was 512 × 480 with 256 gray levels. The obtained results were as follows: 1. At the condition of under exposure, the radiographs were superior to the digital images in readability. Also, as the size of the artificial lesion was increased, readability of the radiographs was elevated. 2. The digital images were superior to the radiographs in readability especially under over exsposure. 3. As the exposure time and size of lesion was increased, the gray level of region of interest of the digital image was decreased proportionally. 4. As the F-value of average gray level of region of interest at individual exposure time and size of lesion, gray level of the all lesion sizes was decreased in comparison with that of the normal enamel.

확장성과 효율성 고려한 DDS 참여자 디스커버리 기법

권기정,유용덕,최훈,Kwon, Ki-Jung,You, Yong-Duck,Choi, Hoon 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.7

The DDS (Data Distribution Service) is a data-centric communication technology that provides an efficient communication service that supports a dynamic plug & play through an automatic setting of participants' location information for each data (Topic) by using DDS discovery technique. This paper proposes the hierarchical-structured DDS discovery technique (SPDP-TBF) suitable for the large-scale distributed systems by comparing and analyzing the existing DDS discovery techniques in terms of performance and problem areas. The proposed SPDP-TBF performs the periodic discovery of the involved participants only by having separate hierarchical managers which take charge of the registration and search (of participants) so that a participant sends its information to the related participants only, and it enhances the effectiveness of the message transfer. Moreover, the proposed SPDP-TBF provides the improved scalability by performing the hierarchical discovery through hierarchical manager nodes so that it can be applied to the large-scale distributed system. DDS(Data Distribution Service)는 데이터 중심의 통신 기술로서 DDS 디스커버리(discovery) 기법을 이용하여 각 데이터(토픽: Topic)에 대한 참여자의 위치정보 자동설정을 통해 참여자의 동적 플러그 앤 플레이를 지원하는 효율적인 통신 서비스를 제공한다. 본 논문에서는 기존 DDS 디스커버리 기법들의 성능 및 문제점들을 비교 및 분석하여 대규모 분산시스템에 적합한 계층적 구조 기반의 DDS 디스커버리 기법(SPDP-TBF)을 제안한다. 제안하는 SPDP-TBF 기법은 등록/검색을 담당하는 별도의 계층별 관리자들을 두어 연관된 참여자들만의 주기적인 디스커버리를 수행함으로써 참여자 정보를 관계된 참여자에게만 전송하여 메시지 전송의 효율성을 높이며, 나아가 계층별 관리자 노드를 통해 계층적 디스커버리를 수행함으로써 대규모 분산시스템에도 적용할 수 있는 높은 확장성을 제공할 수 있다.

방사선 조사선량에 따른 백서 악하선의 caspase-3 발현양상

권기정,최용석,황의환,이상래,고광준,Kwon Ki-Jeong,Choi Yong-Suk,Hwang Eui-Hwan,Lee Sang-Rae,Koh Kwang-Joon 대한영상치의학회 2006 Imaging Science in Dentistry Vol.36 No.1

Purpose : To investigate the caspase-3 expression in the acinar and ductal cells of rat submandibular glands after the irradiation of various doses. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were used for this study. The experimental group was irradiated with a single absorbed dose of 2, 5, 10, and 15 Gy on the head and neck region. The rats were sacrificed on the 1st, 3rd, 7th, 14th, 21 st, and 28th day after irradiation. The specimens including the submandibular gland were sectioned and observed using histopathological and immunohistochemical methods. Results : The local destruction of the acinar and ductal cells and the karyopyknotic nuclei of the acinar cells were observed in the 2 Gy and 5 Gy irradiation groups later than in the 10 Gy and 15 Gy irradiation groups. And the expression of caspase-3 was prominent only in the ductal cells in the 2 Gy and 5 Gy irradiation groups. Conclusion : This experiment suggests that radiation-induced apoptosis in the ductal cells of rat submandibular glands was induced by a low dose radiation associated with the activation of caspase-3 and radiation-induced necrosis was induced by a high dose radiation.

건물 에너지 모니터링과 공간정보 시각화를 이용한 에너지 통합 운영시스템 개발 방안 제안 - 세종시 첫마을 공공건물을 대상으로 한 시스템 구축 사례 -

권기정,이동환,차기춘,박승희,Kwon, KeeJung,Lee, DongHwan,Cha, KiChun,Park, SeungHee 한국BIM학회 2014 KIBIM Magazine Vol.4 No.1

This research and project is going on the Korean government. The objective of project is that developing total energy management solution. So, this paper is going to introduce a proposal that energy total operating system development using spatial information visualization and energy monitoring. It could efficiently operate the building energy wirelessly controling cooling/heating, lighting, air-conditioning and geothermal system. The metering data is collected to total database. The data is linked to BAS gateway, which is connected the device by the standard protocol.

한-중FTA대비 국내 육우산업 가격경쟁력 비교 : 중국 베이징, 상하이 시장조사를 중심으로

권기정,서효동,장선식,박지현,Kwon, Ki Jung,Seo, Hyo Dong,Jang, Sun Sik,Park, Ji Hyun 한국벤처창업학회 2014 벤처창업연구 Vol.9 No.5

2013년 중국의 쇠고기 수입금액이 13.3억 달러(전년대비 4.8배)로 치솟는 등 최근 중국의 쇠고기 소비시장이 급변하고 있다. 글로벌 쇠고기 시장은 이와 같은 중국 시장변화에 주목하며 시장접근 전략마련에 고심하고 있으나, 우리는 한우고기의 낮은 가격경쟁력에만 초점을 맞추다보니 중국을 수출상대국으로서 분석하는 작업이 미흡하였다. 한 중 FTA 등 시장개방이 본격화 될 경우 한우고기 사육농가의 피해방지를 위한 시장 방어적 차원에서의 논의만이 이루어져 오고 있었다. 중국 쇠고기 시장은 가격경쟁이 치열한 저급육 시장이 지배적이지만 품질과 안전을 추구하는 고급육시장이 형성되고 있다. 이에 본 연구팀은 한우고기 수출을 위한 첫걸음으로 중국 1선급 도시인 베이징, 상하이의 쇠고기 가격 및 품질 등에 대한 시장조사를 수행하고, 한우고기의 대중국 쇠고기 시장에서의 가격경쟁력을 분석하였다. 분석결과 한우고기는 우둔, 갈비, 등심 부위가 베이징, 상하이에서 판매되고 있는 중국산, 수입산 쇠고기 고가그룹에서 가격경쟁력 우위를 확보하고 있는 것으로 나타났다. 특히, 베이징에서는 한우고기 우둔과 등심부위가, 상하이에서는 한우고기 갈비와 등심부위가 가격경쟁력이 확보된 것으로 나타났다. Recently, the Chinese beef consumption market has faced a sudden surge. With China's beef imports reaching $1.33 billion in 2013, the global market closely monitors China's rising consumption of beef. Because there have been no exports of Korean beef (Hanwoo) to China previously, the negative effects of opening of beef market between South Korea and China are speculated as the South Korean government advances FTA negotiations further with China. In order to prepare for the opening of beef market between the two nations and to understand Hanwoo's export competitiveness, our research team conducted a market research on beef price and quality in Beijing and Shanghai. Based on our research, we deduced the price of Hanwoo and analyzed the price competitiveness of Hanwoo in the emerging Chinese beef market. Based on the market research, the price competitiveness of Hanwoo's topside/inside, rib and loin are well-positioned compared to Chinese and imported high-end beef group in Beijing and Shanghai market. Specifically, the price competitiveness of Hanwoo's topside/inside and loin are dominant in Beijing while that of rib and loin are dominant in Shanghai.

교정치료 전 환자의 측두하악관절에 관한 방사선학적 연구

권기정,Kwon Ki-Jeong 대한영상치의학회 2001 Imaging Science in Dentistry Vol.31 No.4

Purpose : To determine whether there is a relationship between abnormal temporomandibular joint radiographic findings and age or gender in a sample of preorthodontic patients. Materials and Methods : Individualized corrected sagittal tomographs of 188 temporomandibular joints in 94 preorthodontic patients, aged 11 to 29 years, were taken and viewed by an observer blinded to clinical records. The study population was divided into 2 aged groups (11-15 years and 16-29 years) for comparative purposes. Temporomandibular joint radiographic findings were classified as normal or abnormal. Results: There was no difference in ratio of abnormal to normal findings between the both aged groups. The frequency of osseous abnormalities was similar with that of abnormalities of condylar position. Abnormalities in CP and JS were most frequent in all aged groups. Conclusion : There is no significant difference between ages or genders for temporomandibular joint radiographic abnormalities.

대구지역 중소기업을 위한 산학간 기술이전 장애요인분석에 대한 연구

권기정 ( Gee Jung Kwon ),노미진 ( Mi Jin Noh ) 국제지역학회 2007 국제지역연구 Vol.11 No.1

본 연구는 대구지역의 중소기업을 중심으로 기술이전 실태 및 장애요인 분석을 통해 기술이전을 활성화시키기 위한 것을 목적으로 하고 있다. 이를 위해 본 연구에서는 대구지역의 기술이전 장애요인을 기술적장애요인, 환경적장애요인, 조직적장애요인으로 분류하여 분석하였다. 기술적장애요인으로는 기술개발능력부족과 기술관리능력부족으로, 환경적장애요인으로는 교류 및 의사소통 미비와 상호신뢰도결여라는 요인으로, 조직적장애요인으로는 전문인력부족, 경영자의 관심부족, 관련조직미비로 분류하였다. 이러한 요인들은 독립변수로 정의되었으며, 종속변수로는 기술이전성과에 대한 주관적인 측정 변수로서 만족도와 유용성으로 분류되었다. 분석결과 기술개발 능력부족 요인, 교류 및 의사소통 미비 요인, 관련조직미비 요인은 만족도에 부의 영향을 미쳤으며, 기술개발 능력부족 요인, 교류 및 의사소통 미비 요인, 상호 신뢰도 결여 요인, 전문 인력 부족 요인, 관련 조직 미비 요인이 유용성에 부의 영향이 미치는 것으로 나타났다. 또한 기술 관리 능력 부족 요인, 교류 및 의사소통 미비 요인, 경영자의 관심 부족 요인이 기술이전 경험이 적은 집단과 많은 집단간의 인식의 차이가 있다는 결과가 도출되었다. 이러한 연구결과는 대구지역에서 기업이 기술이전을 할 때에 도움이 되는 여러 가지 지침을 제공할 수 있을 것으로 기대 된다. This paper examines problems of technology transfer between small business and university in Daegu. In this paper, We identify obstacle factors and conditions of the technology transfer. For doing this, We investigated into the relationship between independent factors as obstacle factors(technical failure factor, environmental failure factor, structural failure factor) and dependent factors. The technical failure factor consists of lack of technology development ability and lack of technology management ability. The environmental failure factor consists of lack of communication and lack of reliability. The structural failure factor consists of lack of expert, lack of CEO`s interest, lack of relation department. These factors are to identify independent factors, success factors of technology transfer are to identify dependent factors as satisfaction and usefulness of technology transfer. Investigation analysis shows following results; First, lack of technology development ability and communication have negative impact on satisfaction. Second, lack of technology development ability, communication, reliability, expert, and structural failure have negative impact on usefulness. Third, there are wide different between the firms have many technology transfer experience and the firms do not have in the factors of lack of technology management, communication, CEO`s interest. Drawing on this research model may show result of empirical study and this study may provide companies with valuable guidelines for the technology transfer.

STRAUSS: DDS 를 이용한 컴포넌트 기반 미들웨어 설계

권기정(Ki-Jeong Kwon),최훈(Hoon Choi) 한국통신학회 2006 한국통신학회 학술대회논문집 Vol.2006 No.11

논문 : 지중 환경하에서의 철근콘크리트 구조물의 부식 특성 연구

권기정 ( Ki Jung Kwon ),정해룡 ( Hae Ryong Jung ),박주완 ( Joo Wan Park ) 대한지질공학회 2016 지질공학 Vol.26 No.1

방사성폐기물 처분시설 공학적방벽을 구성하는 콘크리트는 주변 환경의 영향으로 내구 수명에 영향을 받게 된다. 현재까지 개발된 수치해석 모델 및 실험을 통하여 방사성폐기물 처분시설 공학적방벽 소재로 가장 널리 사용되는 콘크리트에 대해 주변환경을 고려하여 그 영향을 살펴보았다. 본 연구에 해당하는 철근 콘크리트 구조물은 지리적으로 해안과 인접한 지하수 포화대에 위치하고 있다. 일반적인 철근콘크리트 구조물의 가장 민감한 열화인자인 염해에 의한 철근부식에 대한 영향을 염화물 확산모델을 이용하여 평가한 결과 철근 부식 개시기간이 1,284년이며, 최종적으로 구조물이 내구수명을 상실하는데 도달하는 시간은 1,924년인 것으로 예측되었다. 또한, Mock-up 실험을 통해 공극분포, 공극률, 부식정도 등 물리화학적 특성을 평가한 결과 콘크리트 내 철근 부식정도는 미비한 것으로 나타나 500년 이상의 상당히 오랜 기간 건전성을 유지할 수 있는 것으로 판단된다. A concrete silo plays an important role in subsurface low- and intermediate-level waste facilities (LILW) by limiting the release of radionuclides from the silo geosphere. However, due to several physical and chemical processes the performance of the concrete structure decreases over time and consequently the concrete loses its effectiveness as a barrier against groundwater inflow and the release of radionuclides. Although a number of processes are responsible for degradation of the silo concrete, it is determined that the main cause is corrosion of the reinforcing steel. Therefore, the time it takes for the silo concrete to fail is calculated based on two factors: the initiation time of corrosion, defined as the time it takes for chloride ions to penetrate through the concrete cover, and the propagation time of corrosion. This paper aims to estimate the time taken for concrete to fail in a LILW disposal facility. Based on the United States Department of Energy (DOE) approach, which indicates that concrete fails completely once 50% of the volume of the reinforcing steel corrodes, the corrosion propagation time is calculated to be 640 years, which is the time it takes for corrosion to penetrate 0.640 cm into the reinforcing steel. In addition to the corrosion propagation time, a diffusion equation is used to calculate the initiation time of corrosion, yielding a time of 1284 years, which post-dates the closure time of the LILW disposal facility if we also consider the 640 years of corrosion propagation. The electrochemical conditions of the passive rebar surface were modified using an acceleration method. This is a useful approach because it can reduce the test time significantly by accelerating the transport of chlorides. Using instrumental analysis, the physicochemical properties of corrosion products were determined, thereby confirming that corrosion occurred, although we did not observe significant cracks in, or expansion of, the concrete. These results are consistent with those of Smartet al., 2006 who reported that corrosion products are easily compressed, meaning that cracks cannot be discerned by eye. Therefore, it is worth noting that rebar corrosion does not strongly influence the hydraulic conductivity of the concrete.

아음속풍동 시험에서의 불확도 해석

권기정(Kijung Kwon),성봉주(Bongzoo Sung) 한국항공우주학회 2002 韓國航空宇宙學會誌 Vol.30 No.4