• Journal of Korean Neurosurgical Society
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• 제41권6호
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• pp.403-407
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• 2007

The authors encountered a case of simultaneous radiation-induced multiple meningiomas and ventriculoperitoneal [VP] shunt-related pneumocephalus. A 35-year-old man, who had undergone surgery for medulloblastoma 21 years previously and subsequently received high dose craniospinal irradiation with adjuvant chemotherapy and later underwent a VP shunt because of hydrocephalus, presented with a severe headache and weakness of both lower extremities. Computed tomography showed an air pocket lesion in the left temporal lobe and a large amount of pneumocephalus with a bony defect of the left tegmen tympani. In addition, a 3 cm sized well enhancing mass was noted in the in the right middle cranial fossa and additional small enhancing nodule in the left frontal pole. He was treated by left temporal craniotomy and repair of the bony and dural defects of the left tegmentum tympanum through extradural and intradural approaches, respectively. Afterwards, he underwent right temporal craniotomy and gross total removal of a rapidly growing right middle fossa mass and a left frontal mass. The histological examination was consistent with atypical meningioma, WHO grade II. In conclusion, physicians have to consider the serious long term complications of high dose radiation therapy and VP shunt placement and need to perform the neuroradiologic follow-up after such treatments for several decades.

• 전기학회논문지P
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• 제59권2호
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• pp.191-196
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• 2010

The electricity distribution system in Korea is adopting a multi-grounding system. Protection of this distribution system against lightning is performed by installing overhead ground wires over the high voltage wires, and connecting the overhead ground wires to the ground every 200 m. The ground resistance in this system is limited not to exceed $50\Omega$ and overhead ground wire and neutral wire are multiple parallel lines. Although overhead ground wire and neutral wire are installed in different locations on the same pole, this circuit configuration has duplicated functions of providing a return path for unbalanced currents and protecting the distribution system against induced lightning. Therefore, the purpose of this study is to analyze the induced lightning shielding effect according to the neutral wire installation structure of a 22.9kV distribution line in order to present a new 22.9kV distribution line structure model and characteristics. This study calculated induced lightning voltage by performing numerical analysis when an overhead ground wire is present in the multi-grounding type 22.9kV distribution line structure, and calculated the induced lightning shielding effect based on this calculated induced lightning voltage. In addition, this study proposed and analyzed an improved distribution line model allowing the use of both overhead wire and neutral wire to be installed in the current distribution lines. The result of MATLAB simulation using the conditions applied by Yokoyama showed almost no difference between the induced lightning voltage developed in the current line and that developed in the proposed line. This signifies that shielding the induced lightning voltage through overhead wire makes no difference between current and proposed distribution line structures. That is, this study found that the ground resistance of the overhead wire had an effect on the induced lightning voltage, and that the induced lightning shielding effect of overhead wire is small.

• Ocean and Polar Research
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• 제26권4호
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• pp.559-565
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• 2004

Total magnetic field measurements were performed to study paleomagnetism of three seamounts (OSM7, OSM8-1, and OSM8-2) to the northwest of the Marshall Islands in the western Pacific. The study area is located at the Ogasawara Fracture Zone which is a boundary between the Pigafetta and East Mariana basins. The magnetic parameters and paleopoles of three seamounts were derived from inversion of the measured magnetic field. The goodness-of-fit ratio of OSM7 is too low to be included to the estimation of parameters. The complex magnetic anomalies of center, scarcity of flank rift zones and steep slope at OSM7 suggest that the multiple intrusions of magma converge into the center of volcanic edifice. Inclination calculated from the magnetic anomalies of OSM8-1 and OSM8-2 is $-41.2^{\circ}$, and the paleolatitude calculated from the inclination is $23.6^{\circ}S$. The corresponding paleopoles for OSM8-1 and OSM8-2 are $(24^{\circ}42'W,\;48^{\circ}54'N)\;and\;(18^{\circ}18'W,\;48^{\circ}30'N)$, respectively. In comparison with the apparent polar wander path (APWP) of the Pacific plate, the paleopoles are close to 129-Ma pole. The paleopoles and paleolatitudes of OSM8-1 and OSM8-2 suggest that they were formed at similar time and location. The seamounts have drifted northward about $41^{\circ}$ from the paleolatitude to present latitude of seamounts.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제7권1호
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• pp.92-97
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• 2004

저자들은 간 이식 후 지속적 비기능 항진에 발생된 내과적 치료에 반응하지 않는 림프세포증식성질환의 6세된 남아에서 부분적 비동맥 색전술을 치료의 한 방법으로 선택하였다. 비기능항진의 억제 효과로 면역력 증강을 통해 혈액학적 호전을 유도하고자 하였으며 치료 후 PTLD의 호전을 보인 1례를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• 한국전자파학회논문지
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• 제26권11호
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• pp.966-977
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• 2015

본 논문에서는 새로운 변형된 동축 공동 공진기를 제안하고, 대역통과 여파기를 설계한다. 제안된 공진기는 하나의 캐비티 내부에 ${\Gamma}$-형 또는 곡선형의 4개의 접지된 도체 포스트로 구성되어 있다. 일반 동축 공동 공진기 여파기와 달리 도체 벽이 없기 때문에 공간 효율이 개선되어 품질계수가 약 15 % 이상 향상되며, 동일한 품질계수 대비 35 % 이상의 크기 소형화가 가능하다. 또한, 인접하지 않은 공진기와 입출력 교차결합을 통해 4개의 조절 가능한 전송영점이 생성되어 차단대역의 감쇄특성을 향상시킬 수 있다. 제안된 여파기와 설계법은 모의실험과 제작 및 측정을 통해 검증되었다.

• Journal of Microbiology
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• 제39권4호
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• pp.286-292
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• 2001

During mitosis. the proper segregation of duplicated chromosomes is corrdinated by a spindle check-point. The bifurcated spindle checkpoint blocks cell cycle progression at metaphase by monitoring unattached kinetochores and inhibits mitotic exit in response to the misorientation of the mitotic spin- dle Ibd1p/Bfa1p is a spindle checkpoint regulator of budding yeast in the Bub2p checkpoint pathway for mitotic exit and its disruption abolishes mitotic arrest when proper organization of the mitotic spin-dls inhibited. Ibd1p/Bfa1p localizes to the spindle pole body, a microtublue-organizing center in yeast, and its overexpression arrests the cell cycle in 80% of cells with an enlarged budy at mitosis and in 20 % of cells with multiple buds. In this study, we found that the C-terminus of Ibd1p/Bfa1p phys-ically interacts with Skp1p, a key component of SCF (Skp1/cullin/F-box) complex for ubiquition-medi-ated proteolysis of cel cycle regulatores as well as an evolutionally conserved kinetochore protein for cell cycle progression. A putative F-box motif was found in the C-terminus of Ibd1p/Bfa1p and its function was investigated by making mutants of conserved residues in the motif. These Ibd1p/Bfa1p mutants of a putative F-box interacted with SKp1p in vitro by two-hybrid assays as wild type Ibd1p/Bfa1p. Also these Ibd1p/Bfa1p utants displayed the overexpression phenotypes of wild type Ibd1p, when over-expressed under inducible promoters . These results suggest that a putative F-box motif of Ibd1p/Bfa1p is not essential for the interaction with SKp1p and its function in mitotic exit and cytokinesis.

• 한국전자파학회논문지
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• 제15권10호
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• pp.977-982
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• 2004

본 논문에서는 유한 시간 차분법(FDTD) 내에서 PLRC(Piecewise Linear Recursive Convolution)법을 이용한 분산성 물질에 대한 비등방성 흡수체(APML)를 제안한다. 제안된 흡수체는 비선형, 분산성 매질 해석시 무한 경계조건을 표현하기 위해 사용될 수 있다. 제안된 흡수체는 기존의 APML 정식화 과정에서 분산 특성을 고려한 것이며 PLRC법의 장점인 빠른 계산시간, 저 메모리 사용, 다극 감수율의 간편한 정식화 등의 장점을 가지고 있다. 개발된 분산성 APML은 드바이(Debye)매질과 로렌츠(Lorentz) 매질 등의 분산성 물질의 해석에 적용하였으며 수치실험을 통해 흡수경계에서 뛰어난 흡수율을 가짐을 보였다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.2045-2049
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• 2018

An antenna arrays for a satellite navigation systems require more antenna elements to mitigate multiple jamming signals. In order to maintain the small array size while increasing the number of antenna elements, miniaturization technique is essential for antenna design. In this work, an electrically small circular microstrip patch antenna with a 3 dB hybrid coupler is designed as an element antenna, where the 3 dB hybrid coupler can yield the circularly polarized radiation characteristic. The miniaturized element antenna typically has too large capacitance in GPS L1 and GLONASS G1 bands, making it difficult to match with a single stand-alone non-Foster matching circuit (NFMC) in a stable state. Therefore, we propose a new matching technique, referred to as the hybrid matching method, which consists of a NFMC and a passive circuit. This passive tuning circuit manages reactance of antenna elements at an appropriate capacitance without a pole in the operating frequency range. The antenna array is fabricated, and the measured results show a reflection coefficient of less than -10 dB and an isolation of greater than 50 dB. In addition, peak gain of the proposed antenna is increased by 22.3 dB compared to the antenna without the hybrid matching network.

• 한국정보통신학회논문지
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• 제6권1호
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• pp.6-13
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• 2002

본 논문은 선형 행렬 부등식 (LMI) 기법을 이용하여, 도립진자 시스템의 안정화 조절 제어 및 추종 제어 특성을 만족하는 다목적 제어기를 선계하기 위하여, 도립진자의 모델을 복수개의 모델을 원소로 가진 폴리토프 모델(polytopic model)로 표현하고, 극점 배치 Η$_2$/Η$_{\infty}$ 제어기를 설계하는 과정을 예시한 것이다. 도립진자의 진폭이 비교적 큰 경우, 하나의 동작점에서 구한 선형 시불변 모델의 오차를 불확실성으로 고려하여 설계한 제어기가 가지기 쉬운 보수성(conservativeness)을 극복하기 위하여, 도립진자 시스템에 대하여 다수의 경사 각도를 선형화의 동작점으로 취하여 복수개의 선형시불변 모델로써 이루어진 하나의 폴리토프 모델(polytopic model)을 구성하였다. 이 모델에 대하여, 볼록 최적화(convex optimization) 알고리즘을 사용하는 LMI 소프트웨어를 사용하여 다목적 성능을 만족하는 제어기를 설계하였다. 폴리토프 모델에 대하여 설계된 제어기로써 제어된 도립 진자는, 비교적 큰 경사 각도의 초기치에 대한 실험에서, 안정하게 연직 위치로 복원되는 제어 효과를 관찰할 수 있었다.

• 한국응용곤충학회지
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• 제52권4호
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• pp.341-348
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• 2013

비래해충인 멸강나방 성충의 발생을 실시간으로 예찰하기 위하여, 성페로몬 트랩에 원격감지장치를 설치한 트랩의 운용 효율성을 검정하였다. 원격감지트랩은 콘트랩 기반에 곤충의 유입을 광차단으로 감지하는 센서부, 신호전송부, 태양열기반의 전력공급부, 트랩 지지대, 웹페이지 기반의 자료수집부로 구성되었다. 연구과정에서 멸강나방 수컷 성충의 밤 시간대 포획의 일일주기성을 이용한 신호감지 시간대 축소, 신호발생 프로그램 조절, 1시간 간격의 전송간격, 신호전송 프로그램 변형 등을 통해 포획 나방수와 감지신호 발생 수의 격차를 줄여 최종적으로 신호 정확도를 92% 이상으로 개선하였다. 또한 실제 멸강나방 성충의 발생양상과 원격감지트랩에서의 신호 발생양상의 상관계수가 0.98이상으로 원격감지트랩에서의 신호 발생이 멸강나방 발생 양상을 정확하게 반영하는 것으로 나타났다. 2011~2012년 멸강나방은 연중 여러 번 발생되는 것이 관찰되었는데, 모두 짧은 기간 동안 발생되어 가파른 피크가 특징이었다.