강자기장이 인가된 물 속에서 고에너지 전자의 궤적 계산

김정기,오영기,신교철,김기환,김진기,김성규,노태익,김진영,지영훈,정동혁,Kim Jeung Kee,Oh Young Kee,Shin Kyo Chul,Kim Ki Hwan,Kim Jhin Kee,Kim Sung Kyu,Ro Tae Ik,Kim Jin Young,Ji Young Hun,Jeong Dong Hyeok 한국의학물리학회 2004 의학물리 Vol.15 No.3

The trajectories for high-energy electrons in water under magnetic fields were calculated approximately by numerical method. A differential equation for electrons under magnetic field was built and the calculation code was devised by Euler method. Using the code, the trajectories for electrons with energies of 3, 5, 10, and 15 MeV in water were calculated in the presence of magnetic fields parallel and perpendicular to the incident electrons. Since we considered only the energy loss and the directional change for primary electrons, there are errors in this calculation. However, based on the results we were able to explain the variation of dose distributions by the external magnetic fields in water. 본 연구에서는 수치해석을 이용하여 강자기장이 인가된 물팬텀 속에서 고에너지 전자의 경로를 근사적으로 계산하였다. 이를 위하여 자기장에서 전자의 방향변화에 관한 방정식을 세우고 오일러(Euler) 방법을 적용하여 전산코드로 구현하였다. 전산코드를 이용하여 입사전자와 수직 및 수평방향의 자기장이 인가된 물팬텀에 대하여 3, 5, 10, 15 MeV 전자의 궤적을 계산하였다. 본 결과는 전자의 다중산란이 고려되지 않아 실제 궤적과 차이가 있으나, 결과로부터 외부 자기장에 의한 물팬텀 속 선량분포의 변화를 설명할 수 있다.

Cold Stress가 노화(老化) 흰쥐 심근(心筋)에 미치는 영향(影響)

김정기,정형재,이용덕,박원학,Kim, Jeong-Ki,Chung, Hyeung-Jae,Lee, Yong-Deok,Park, Won-Hark 한국현미경학회 1998 Applied microscopy Vol.28 No.1

The present study was performed to determine the effect of cold stress on myocardium of aging rat. Control groups, which aged 6, 12 and 24 months, were compared with age-matched experimental groups that were exposed to moderate cold stress for a hours daily in a week at laboratory cold room $(4{\pm}1^{\circ}C)$. The histological, histochemical and ultrastructural changes of myocardium were observed. The results were summarized as follow: 1. Age-dependent histological change of control groups was observed the formation of contraction band in 24months aged group. The experimental groups submitted to cold stress showed a similar change pattern as seen in control groups. However, the degree of change in the experimental groups was significantly larger than that of control groups. In the 34 months aged group the formation of hypercontraction band was observed. 2. Regarding age-dependent histochemical changes of control groups, we observed the increase activities of PAS and Masson's trichrome. In experimental groups the activities of PAS and Masson's trichrome were also increased with age. Compare with control group, the activities of PAS was increased but the activities of Masson's trichrome was decreased. 3. Age-dependent ultrastructural changes on vacuolization, lysosome were observed. In control groups the structural changes occur at 12 months. The accumulation of lipofuscin, contraction band, hypercontraction band and a component of connective tissue were observed in 24 months. However, the degree of change in the experimental groups was significantly larger than that of control groups. In contract, the myelin body in intercalated discs was observed in 24 months of experimental groups.

임베디드 플래시 파일시스템을 위한 순위별 지움 정책

김정기,박승민,김채규,Kim, Jeong-Ki,Park, Sung-Min,Kim, Chae-Kyu 한국정보처리학회 2002 정보처리학회논문지 A Vol.9 No.4

최근 정보 산업과 이동통신 기술이 발전함에 따라 PDA(personal digital assistant), HPC(hand-held PC), 세탑박스(set-top box), 정보가전 등의 임베디드 시스템(embedded system)이 개발되고 있으며, 이러한 시스템을 운영할 실시간 운영체제(RTOS)와파일시스템의 요구는 필수적이다. 휴대의 용이성과 빠른 접근시간, 저전력을 요구하는 임베드 시스템의 특성상 데이터를 저장하기 위한 저장 매체로 하드디스크(hard disk)를 이용하는 것은 비효율적이며, 플래시 메모리(flash memory)가 주로 사용되고 있다. 플래시 메모리는 비휘발성과 빠른 접근 시간을 갖는 장점이 있지만, 상대적으로 느린 지움 시간과 지움 회수의 한계 등은 극복해야 할 문제점이다. 본 논문에서는 이러한 단점을 보완하기 위해 새로운 순위별 지움 정책을 제안하고 성능평가를 실시한다. 지움 정책의 일반적인 역할은 플래시 메모리 공간의 어디를 언제 지울 것인가를 결정한다. 제안된 순위별 지움 정책은 지우는 비용과 한정된 지움 회수를 고려하여 지우는 광간과 시간을 결정함으로써 플래시 메모리의 수명을 최대한 연장하고 플래시 메모리 접근 및 관리의 성능을 향상시킨다. 제안된 방법은 기존의 Greedy 및 Cost-benefit 방법에 비해 저장 연산 수행에서 10%~50%의 성능 향상을 보인다. Along the evolution of information and communication technologies, manufacturing embedded systems such as PDA (personal digital assistant), HPC (hand -held PC), settop box. and information appliance became realistic. And RTOS (real-time operating system) and filesystem have been played essential re]os within the embedded systems as well. For the filesystem of embedded systems, flash memory has been used extensively instead of traditional hard disk drives because of embedded system's requirements like portability, fast access time, and low power consumption. Other than these requirements, nonvolatile storage characteristic of flash memory is another reason for wide adoption in industry. However, there are some technical challenges to cope with to use the flash memory as an indispensable component of the embedded systems. These would be relatively slow cleaning time and the limited number of times to write-and-clean. In this paper, a new cleaning policy is proposed to overcome the problems mentioned above and relevant performance comparison results will be provided. Ranking cleaning policy(RCP) decides when and where to clean within the flash memory considering the cost of cleaning and the number of times of cleaning. This method will maximize not only the lifetime of flash memory but also the performance of access time and manageability. As a result of performance comparison, RCP has showed about 10 ~ 50% of performance evolution compared to traditional policies, Greedy and Cost-benefit methods, by write throughputs.

금성전투와 쿠이토 쿠아나발레(Cuito uanavale) 전투에 대한 비교 연구: 용병술 차원의 관점에서

김정기 ( Kim Jeong-ki ) 한국군사학회 2021 군사논단 Vol.105 No.-

Even though Korea is far from Angola in Africa, Korean war and Angolan war have many similarities. This thesis comparatively reinterpreted Gumsung and Cuito Cuanavale battles with the levels of war(strategic, operational, and tactical level). With studying reciprocal relations among strategic objectives, operational maneuvers, and tactical actions, this thesis compared the reasons and results of the two battles to extract the relative success or failure. Despite the battle is a part of the war, the decisive battle influences on the war's whole scale. On the two Gumsung and Cuito Cuanavale battles in the period of ending wars, analyzing linkages for levels of warfare was useful to study factors of relative success or failure. As a result, COF excluded ROKF to sign KAA and ITF eliminated UNITA to join NYA harmonized operational maneuvers and tactical actions to strategic objectives. On the other hand, UNF and LBF failed to clear strategic objectives, rather tried to expand operations to strategic levels or respond operational maneuvers with tactical actions. Consequently, a lesson learned from this study is that the relative success of battles come from clear strategic objectives supported by operational maneuvers and tactical actions. The lesson is almost a kind of military doctrine across all ages and countries was reconfirmed through this study. In addition, this case study took a important look at the hierarchy of ‘Politics → Diplomacy → Military(Strategic → Operational → Tactical).’ Because strategic objectives was effective when those aligned to the political purpose with diplomatic negotiations controlling levels of warfare during the period of ending wars.

론《수호전》중적 발분지어

김정기 ( Jeong Ki Kim ) 중국어문연구회 2002 中國語文論叢 Vol.23 No.-

한국의 앙골라 PKO 부대 파병정책 결정과정 고찰

김정기(Kim, Jeong-ki) 국방부 군사편찬연구소 2020 군사 Vol.- No.117

Republic of Korea(ROK) sent the first group of Engineer forces on October, 1995 as a contingent of the United Nation Angola Verification Mission III(UNAVEM III) for Peacekeeping Operation(PKO) to Angola. Which was initiated by requesting of the UN on February, 1995. Dispatching to Angola is a unique case because it was decided during the period of aftereffect from dispatch to Somalia. And it was not the same engineer unit as others, which was to repair bridges and reconstruct in the area Angola. These facts stimulate this paper to be begun. What made the dispatch to Angola possible? To answer that questions is the goal of this study. The Win-sets conception of two-levels game theory was used to study the decision making process of the unit"s deployment and to investigate solution of discords between ROK and UN. The result of this study is that the security issue was the main factor of win-sets for ROK to negotiate, whereas, the mandates for UN was the main one. With the win-sets, the process of decision to send a Engineer PKO unit had to follow two-levels game including the possible agreement between ROK and UN, and the final ratification of ROK"s National Assembly. And the discords about for mission area and the post was also solved on the base of the win-sets of them as well.

WiBro 시스템을 위한 고속 LDPC 인코더 설계

김정기(Jeong Ki Kim),발라카난(Balakannan S.P),이문호(Moon Ho Lee) 대한전자공학회 2008 電子工學會論文誌-TC (Telecommunications) Vol.45 No.7

Low Density Parity Check codes(LDPC)는 최근 우수한 성능으로 통신 분야에서 채널 코딩의 중요한 블록으로 주목받고 있다. 그리하여 Wibro를 포함한 여러 표준에서 LDPC 부호를 채널 코딩으로 채택하고 있다. 이러한 LDPC 부호의 Encoder를 구현하는데 있어서의 약점은 기존의 이진 Matrix Vector Multiplier가 throughput의 감소의 원인이 되는 clock cycle이 많다는 것이다. 본 논문은 표준에서 사용되는 H 행렬이 Circulant Permutation Matrix(CPM)로 정의되어 있다는 점을 이용하여 인코더의 구현에 있어서 기존의 Matrix Vector Multiplier 대신에 cyclic shift register와 exclusive-OR을 사용하는 설계구조를 제안한다. 또한, 제안한 구조를 이용하여 WiBro에 포함되는 다양한 부호율에 적용가능한 인코더를 설계하였다. 제안된 WiBro LDPC의 인코더는 기존보다 적은 clock cycle을 가지므로 높은 throughput에 도달한다. Low Density Parity Check codes(LDPC) are recently focused on communication systems due to its good performance. The standard of WiBro has also included LDPC codes as a channel coding. The weak point of implementation for LDPC encoder is that conventional binary Matrix Vector Multiplier has many clock cycles which limit throughput. In this paper, we propose semi-parallel architecture by using cyclic shift registers and exclusive-OR without conventional Matrix Vector Multipliers over the standard parity check matrices with Circulant Permutation Matrices(CPM). Furthermore, multi-rate encoder is designed by using proposed architecture. Our encoder with multi-rate for IEEE 802.16e LDPC has lower clock cycles and higher throughput.

Colchicine 처리후 흰쥐 뇌에서 Brain-Derived Neurotrophic Factor 면역반응 신경세포의 분포

김정기(Jeong-Ki Kim),박원학(Won-Hark Park),조희중(Hee-Jung Cho) 대한해부학회 1999 Anatomy & Cell Biology Vol.32 No.6

Brain-derived neurotrophic factor (BDNF) mRNA 및 BDNF는 뇌에서 광범위하게 분포함이 밝혀져 있다. BDNF mRNA와 BDNF는 그 분포에 있어서 서로 일치하는 부위가 많지만 그렇지 않은 부위도 많다. 본 연구에서는 BDNF mRNA는 발현되 지만 BDNF가 발현되지 않는 부위에서 BDNF의 발현을 보기 위하여 뇌실에 colchicine을 투여한 후 면역조직화학기법을 시 행한 결과 다음의 사실들을 알 수 있었다. 1. 앞후각핵, 조롱박겉질, 대뇌겉질, 담장, CA2와 CA3의 피라밋층, 치아이랑의 과립세포층, 바닥가쪽편도핵, 가쪽무릎핵, 앞 안쪽시상핵, 앞등쪽시상핵, 뇌실곁시상핵, 뇌실곁시상하부핵 및 배쪽안쪽시상하부핵에서는 colchicine 비처리군에 비하여 BDNF 면역반응 신경세포가 증가하였다. 2. CA1의 피라밋층, A1, A2, A4-A10 세포군, C1-C3 세포군, 큰솔기핵, 가쪽거대세포핵 및 척수안뜰신경핵에서는 colchicine 처리 후 새로이 많은 BDNF 면역반응 신경세포가 관찰되었다. 이상의 결과는 colchicine 처리 후 흰쥐 뇌에서 BDNF 함유 신경세포들은 그 분포에 있어서 BDNF mRNA 함유 신경세포 와 일치함을 알 수 있었다. Widespread brain-derived neurotrophic factor (BDNF) mRNA and protein expression has been detected in the brain. Despite substantial overlap between BDNF mRNA and protein expression, there is general anatomical regions, where there is discordance of these expression. We performed, therefore, immunohistochemistry after colchicine treatment into the ventricle to evaluate the possible presence of BDNF-immunoreactive (IR) in the regions where BDNF mRNA was expressed, but not BDNF-IR. The results obtained were as follows; There was substantial increase in the number of BDNF-IR neurons in the anterior olfactory nucleus, the piriform cortex, the cerebral cortex, the claustrum, the stratum pyramidale of the CA2 and the CA3, the granule cell layer of the dentate gyrus, the basolateral amygdaloid nucleus, the lateral geniculate nucleus, the anteromedial thalamic nucleus, the anterodorsal thalamic nucleus, the paraventricular thalamic nucleus, the paraventricular hypothalamic nucleus and the ventromedial hypothalamus nucleus, compared to the same brain area of non-colchicine treated rat. We detected many new BDNF-IR neurons in the stratum pyramidale of the CA1, A1, A2, A4-A10 cell groups, C1-C3 cell groups, the raphe magnus nucleus, the lateral paragigantocellular nucleus and the spinal vestibular nucleus. The results show that the localization of BDNF-IR neurons after colchicine treatment is consistant with that of BDNF mRNA containing neurons in the brain.

Gum Tissue를 절개하지 않고 Cherchēve Spiral Implant를 매식한 Single Tooth Restoration의 증례보고

김정기(Jeong Ki, Kim) 대한치과의사협회 1993 대한치과의사협회지 Vol.31 No.1

애드 혹 네트워크에서 전송률을 따른 적응적 소스 라우팅 프로토콜

김정기(Jeong-Ki Kim),김우재(Woo-Jae Kim),서영주(Young-Joo Suh) 한국통신학회 2005 한국통신학회 학술대회 및 강연회 Vol.2005 No.4