• Radiation Oncology Journal
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• v.15 no.4
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• pp.339-348
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• 1997

Purpose : To evaluate the role of postoperative radiation therapy after curative resection of sigmoid colon cancer Materials and Methods : From 1988 to 1993, a total of 93 Patients with curative resectable sigmoid colon cancer of modified Astler-Coiler (MAC) stage B2, B3, C2, C3 was divided into two groups on the basis of those who received radiation treatment and those who did not. Forty-three patients who treated by surgery alone were classified as postop RT (-) group The remaining 50 patients who underwent postoperative radiotherapy were classified as postop RT (+) group. In all patients in Postop RT (+) group. radiation therapy was delivered using 4 or 10 MV linear accelerators to treat the tumor bed with approximately 5cm margin to a total dose 50.4-61Gy(median 54Gy) in 1.8Gy per fraction. Thirty-two patients were treated. with 5-Fluorouracil based adjuvant chemotherapy at least 3 cycles. but these was no significant difference between two groups. Treatment failure Pattern, 5-year local failure-free survival rates (LFFS), and 5-year disease-free survival rates (DFS) were compared between two groups. Result : Five year LFFS and DFS were $85.1\%,\;68.5\%$, respectively, In Postop RT (-) group, LFFS was $76.2\%$ compared with $91.7\%$ in Postop RT (+) group. Improved LFFS and DFS were seen for patients with stage C3 sigmoid colon carcinoma with postoperative radiation therapy compared with postop RT (-) group (P=0.01, p=0.06 respectively), in stage B3, LFFS washigher in postop RT (+) group than that in Postop RT (-) group. although itwas not significant. Especially, local control was higher in stage 74 inpostop RT (+) group than that in postop RT (-) group, Conclusion : This studv showed significantly improved LFFS and DFS in MAC Stage C3 and improved tendency of LFFS and DFS in MAC Stage B3 disease. Large scale prospective study is required to verify the role of adjuvant radiation therapy in resectable sigmoid colon cancer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1913-1920
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• 2009

An intelligent accurate sun tracking controller for solar lighting system was developed. This controller can detect the faulty sensor and correct the error signal based on Principle Component Analysis theory. A fuzzy controller was developed to control the tracker by using the collected sensor signal for precise position control. Also a multiple range searching sensor module for sun tracking was designed. To show the validity of the developed system, some experiments in the field were illustrated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.269-281
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• 2014

In this paper, a systematic design of a low phase noise voltage-tuned dielectric resonator oscillator(VTDRO) using loop group delay is proposed. Designed VTDRO is closed-loop type and consists of a cascade connection of a resonator, phase shifter, and amplifier. Firstly, a reference VTDRO is fabricated and its phase noise and electrical frequency tuning range are measured. Both the phase noise and electrical frequency tuning range depend on the loop group delay. Then, a required value of loop group delay for a new VTDRO with a low phase noise can be systematically computed. In addition, its phase noise and electrical frequency tuning range can be theoretically estimated using those obtained from the measurement of the reference VTDRO. When the loop group delay increases, the phase noise decreases and the electrical frequency tuning range also decreases. The former predominantly depends on the resonator structure. Therefore we propose a systematic design procedure of a resonator with high group delay characteristics. The measured loop group delay of the new VTDRO is about 700 nsec. The measured phase noise of the new VTDRO show a state-of-the-art performance of 154.5 dBc/Hz at 100 kHz frequency offset and electrical frequency tuning range of 448 kHz for a voltage change of 0~10V. The oscillation power is about 4.39 dBm.

• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.6
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• pp.627-633
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• 1999

In this paper, we propose a method of cooperative control (T-cell modeling) and selection of group behavior strategy (B-cell modeling) based on immune system in distributed autonomous robotic system (DARS). Immune system is living body's self-protection and self-maintenance system. These features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For applying immune system to DARS, a robot is regarded as a ？3-cell, each environmental condition as an antigen, a behavior strategy as an antibody and control parameter as a T-cell respectively. When the environmental condition (antigen) changes, a robot selects an appropriate behavior strategy (antibody). And its behavior strategy is stimulated and suppressed by other robot using communication (immune network). Finally much stimulated strateby is adopted as a swarm behavior strategy. This control scheme is based on clonal selection and immune network hypothesis, and it is used for decision making of optimal swarm strategy. Adaptation ability of robot is enhanced by adding T-cell model as a control parameter in dynamic environments.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.480-481
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• 2018

본 논문에서는 대용량 에너지저장 시스템을 효율적으로 구성 및 운용하기 위해 배터리 군을 여러 군으로 분리하고, 각 군을 Half-bridge 전력변환기와 결합한 새로운 토폴로지를 제안한다. 또한 제안된 스위칭방식에 의해 넓은 입력 범위에서 충 방전할 수 있으며, 배터리의 SOC 추정이 용이하게 할 수 있어 직렬로 연결된 배터리 군의 SOC 밸런싱 제어가 가능하게 하였다. 또한 시뮬레이션을 통하여 제안된 방식의 타당성을 검증 하였다.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.88-94
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• 2008

In this study, triaxial velocity is analyzed for COMS(Communication, Ocean and Meteorological Satellite) configuration, which is generated when thrusters are used to dump wheel momentum. Since COMS is designed to periodically change the thruster set in order to uniformly decrease the performance of thrusters, triaxial velocity would be different during the change of thruster set. So, the triaxial velocity generated due to the change of thruster set is optimized.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.61-71
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• 2003

In the study of control technique for a turbojet engine model, the Takagi-Sugeno fuzzy logic controller has been designed based on the model identification by the well designed PI controlled system through T-S neuro-fuzzy inference system. To enhance this designed controller, those procedures are proposed that certainty factors are adopted to each rule of objective groups which are classified by the fuzzy C-Means algorithm and the satisfaction degrees are matched to meet the objectives. This proposed technique shows its feasibility by upgrading performances of the previously well-designed T-S fuzzy controller.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.21-21
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• 2001

일반적으로 세포는 방사능이나 항암제 등의 자극에 의해 DNA가 손상받았을 때 DNA를 합성하기 전, DNA변이를 복구하기 위해 cell cycle을 정지시키게 된다. pRB(retinoblatoma protein)는 이러한 cell cycle의 조절기작에서 중요한 역할을 담당하는 것으로 알려져 있다. G1기에서 S기로 진행하는 것을 조절하는 단백질인 pRB 은 E2F(cell cycle transcription factor)와 상호작용하여 cell cycle 진행에 필요한 전사활성을 억제, PCNA (proliferating cell nuclear antigen)의 합성을 저해한다. 또한, E2F와 결합된 pRB는 apoptosis를 제어하는 유전자를 조절하는 것으로 알려져 있다. Cell cycle에 영향을 미치는 항암제의 일종인 busulfan을 처리하면, 정소 내에 존재하는 대부분의 생식세포들은 사멸되고 spermatogonia만 남는 것으로 알려져 있다. 그러나 그 기작에 대해서는 자세히 연구된 바가 없다. 본 연구에서는 busulfan처리시 spermatogonial stem cell이 어떤 기작에 의해 손상받지 않고 유지되는지를 알아보고자 실험을 수행하였다. Busulfan을 처리한 마우스 (항암제 투여 후 5주)와 정상적인 13주령의 마우스의 정소로부터 각각 세포를 분리하였다. LSC (laser scanning cytometry)를 이용하여 처리군(busulfan treated mice)과 대조군(normal mature mice)에 대해 각각 DNA함량을 비교ㆍ분석한 결과 G0/G1(2N)에 머물러 있는 세포비율이 처리군에서 현저하게 증가했다 (79.3$\pm$5.5%:8.1$\pm$1.3%). Cell cycle의 G1/S check point인 pRB와 PCNA 발현을 Western blot과 면역조직학적인 방법(immunohisto-chemistry)을 이용하여 조사하였다 PCNA는 대조군과 비교해, 처리군에서 매우 낮은 수준으로 발현되었다. 면역염색된 정소단면을 살펴보면, 대조군에서는 모든 세정관에서 PCNA를 발현하는 세포가 높은 비율로 검출되었고, 처리군에서는 소수의 세정관에서 세포들이 낮은 수준으로 검출되었다. 반면에, pRB의 경우 PCNA와는 상반된 결과를 나타내어, 대조군에서는 거의 발현이 되지 않는 반면, 처리군에서는 대부분의 세정관내, 기저막을 따라 위치한 세포들에서 발현되었다. 이상의 결과는 busulfan에 의해 pRB의 인산화가 억제, pRB 와 결합된 E2F는 전사 활성이 억제되어, PCNA 합성을 저해하는 것으로 설명되어질 수 있다. 결론적으로, 인산화가 억제된 pRB (underphosphorylated RB protein)이 quiescent spermatogonial stem cell에서만 특이하게 발현하는 단백질이며, 이러한 pRB의 발현은 apoptosis를 제어하는 역할을 담당해 busulfan처리에 의해 손상받지 않고 남아있는 것으로 시사된다.

• 월간 기계설비
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• s.126
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• pp.49-57
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• 2001

• 월간 기계설비
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• s.125
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• pp.26-37
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• 2000