• 대한기계학회논문집A
• /
• 제26권4호
• /
• pp.602-608
• /
• 2002

The flexible structure like solar array and antenna in spacecraft shows very sensitive responses to the inner or outer disturbance and noise. And the spacecraft becomes more complex and larger as it has various mission and role. But since the spacecraft need to have the limited mass, the thin and light material should be selected and this necessity induces the decrease d natural frequency and structural stiffness. It reduces the ability of adapting to the disturbance and induces the structural unstability. Certainly, the disturbance does not only make the structural unstability, but also give the bad effect to the precise attitude control. So it is necessary to control the vibration in the space. In this paper, the flexible structure control modeling with piezo sensor and piezo actuator is developed. The model uncertainty of damping ratio is overcome by robust control. The system equation is induced by the finite element method.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 추계종합학술대회
• /
• pp.191-194
• /
• 2005

본 논문은 이동로봇을 위한 위치 및 물체인식용 지능형 센서 제어 시스템에 대해 기술한다. 개발된 센서시스템은 저가의 광PSD(Position sensitive detector)를 사용하였다. PSD센서는 저가이고, 가볍다는 장점이 있지만 많은 noise를 갖고 있다. 본 논문에서는 이러한 noise를 효과적으로 제거하기 위해 hardware filter와 software filter를 제안한다. 또한 선분기반 map building을 위해 개선된 Hough transform 알고리즘과 이동로봇의 실내 환경에서의 navigation 알고리즘을 제안한다. 개발된 시스템은 실험을 통해 증명하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권5호
• /
• pp.1666-1689
• /
• 2021

The red line of Permanent Basic Farmland is the most important part in the "three-line" demarcation of China's national territorial development plan. The scientific and reasonable delineation of the red line is a major strategic measure being taken by China to improve its ability to safeguard the practical interests of farmers and guarantee national food security. The delineation of Permanent Basic Farmland zoning (DPBFZ) is essentially a multi-objective optimization problem. However, the traditional method of demarcation does not take into account the synergistic development goals of conservation of cultivated land utilization, ecological conservation, or urban expansion. Therefore, this research introduces the idea of artificial immune optimization and proposes a multi-objective model of DPBFZ red line delineation based on a clone selection algorithm. This research proposes an objective functional system consisting of these three sub-objectives: optimal quality of cropland, spatially concentrated distribution, and stability of cropland. It also takes into consideration constraints such as the red line of ecological protection, topography, and space for major development projects. The mathematical formal expressions for the objectives and constraints are given in the paper, and a multi-objective optimal decision model with multiple constraints for the DPBFZ problem is constructed based on the clone selection algorithm. An antibody coding scheme was designed according to the spatial pattern of DPBFZ zoning. In addition, the antibody-antigen affinity function, the clone mechanism, and mutation strategy were constructed and improved to solve the DPBFZ problem with a spatial optimization feature. Finally, Tongxu County in Henan province was selected as the study area, and a controlled experiment was set up according to different target preferences. The results show that the model proposed in this paper is operational in the work of delineating DPBFZ. It not only avoids the adverse effects of subjective factors in the delineation process but also provides multiple scenarios DPBFZ layouts for decision makers by adjusting the weighting of the objective function.

• 한국광학회지
• /
• 제13권1호
• /
• pp.1-8
• /
• 2002

지구관측위성의 해상도가 정밀해 짐에 따라 광학 탑재체 즉 카메라의 구경이 대구경화 되고 있으며, 이에 따라 발사 및 운용환경에서 주어진 광학성능을 만족하는 설계/가공/조립과 함께 광학계의 경량화가 주요 요구 사항이 되어졌다. 반사경은 수차 및 광경로 등의 광학적 이유와 가공성 등의 이유로 대구경 광학계에서 사용되고 있으며, 위성용 광학계의 경량화의 상당 부분이 반사경 경량화를 통하여 이뤄지고 있다. 본 논문에서는 직경 30cm의 플랫 백, 싱글 아치, 더블 아치, 벌집 샌드위치 반사경에 대하여 위성용 반사경의 주요 형상 변형 요인을 대표할 수 있는 구조해석과 열 해석을 동시에 수행하여 각 반사경의 변형을 구하였고 광학 성분(Zernike다항식)과 이의 효과를 분석하였다. 더 나아가, 이러한 결과와 비례의 법칙 및 Valente의 무게 예상 공식을 사용하여 직경이 300-1000mm가지의 반사경의 기계변형을 추정하였으며, 이를 바탕으로 네 가지 모델의 적용 가능 구간 및 자동초점기능을 적용하였을 때의 성능향상을 계산하였다.

• Journal of Korean Neurosurgical Society
• /
• 제37권4호
• /
• pp.287-292
• /
• 2005

Objective: Recent clinical studies have demonstrated that intracisternal administration of recombinant tissue plasminogen activator(rt-PA) can facilitate the normal clearing of blood from the subarachnoid space. Urokinase, a first generation fibrinolytic agent, has been used to liquify such clots with some success. Therefore, recombinant tissue plasminogen activator, a second generation fibrinolytic drug that may be safer and more effective, is studied to evaluate its dosage to lyse clots in vitro and reactivity in the brain parenchyme. Methods: Intracerebral hematomas were created by stereotactically injecting 2ml of clotted autogenous blood into the brain parenchyme of total 28 anesthetized adult cats (weighting 3.8 to 4.1 kg). The control animals (group A) received 1 ml of normal saline injected into the clots and the experimental animals received each 0.1 mg of rt-PA (group B), 0.5mg of rt-PA (group C) and 1 mg of rt-PA (group D) at 6 hours after the clot injection. Results: 1. The amount of remained clots after lysing the hematomas were as follows: $1.80{\pm}0.17ml$ in group A, $1.65{\pm}0.23ml$ in group B, $0.61{\pm}0.37ml$ in group C and $0.52{\pm}0.34$ in group D. The result indicated that hematomas in rt-PA treated groups (C & D) were lysed better than the control group. 2. At least 0.5mg of rt-PA should be required for the lysis of 2ml of hematomas. 3. Light microscopic examination revealed no histological evidence of hemorrhage in tissue sections from each brain. Conclusion: Recombinant tissue plasminogen activator may be safely and effectively employed for the lysis of intracerebral hematomas in animal model.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제22권2호
• /
• pp.133-141
• /
• 2000

Purpose : The purpose of this study is to estabilish clinical guidance of microvascular anastomosis in diabetic patients. This study was performed with experimental microvascular anastomosis in streptozotocin induced diabetic rats and observed histopathologic change and endohelial healing process. Materials and Methods : 70 Sprague-Dawley rats, weighting 200 to 250grams, were used for the experiment. 35 induced diabetic rats with streptozotocin and 35 control group were selected. After end-to-end carotid artery microvascular anastomosis was done, the experimental rats were sacrificed at different time interval (1st day, 3rd day, 1st week, 2nd, 4th, 6th and 8th week) for histologic examination. Light microscope observation was used in this study. Results : 1. Histopathologic changes are nearly the same healing process in two groups. But period of tissue reaction was faster in the control than diabetic group. 2. In endotheliall healing, control group started at 1 week after and completed at 4 weeks after, but diabetic group was observed partially at 4 weeks after and complete healing was not observed still at 8 weeks after. 3. In subintimal hyperplasia, control group was observed at 6 weeks after but diabetic group was observed at 6 weeks after and partially at 8 weeks after. 4. All groups showed severe inflammatory response in the early period. This respond is decreased at 2 weeks after in control group but still remained at 8 weeks after in the diabetic group. 5. In media, inflammatory response and degeneration were observed in early period. Regeneration of smooth muscle cell was observed at 1 week after in control group but 4 weeks after in the diabetic group. Conclusions : As the results of study, it could be thought that vascular regeneration process was not failured but delayed in the diabetes. It was considered that diabetes mellitus was not absolute contraindication of microvascular anastomosis.

• 한국정보통신학회논문지
• /
• 제16권8호
• /
• pp.1593-1598
• /
• 2012

본 논문에서는 실시간으로 변하는 차량에 따라 퍼지 제어 기법을 이용하여 교통 신호를 효율적으로 제어하는 방법을 제안한다. 제안된 교통 신호 제어 방법은 교차로 각 차선에 대해 구간을 나누어서 각 구간의 차량의 수와 점유 시간에 대한 소속 함수를 설계한다. 설계된 소속 함수에서 소속도를 구한 후 퍼지 제어 규칙을 적용하여 Max-Min 방법으로 추론한다. 그리고 비퍼지화를 수행한 후에 우선순위를 정한다. 우선순위가 같을 경우에는 점유시간과 차량 수의 비율의 합, 각 구간에 대한 표준편차를 이용하여 우선순위를 정한다. 가장 높은 우선순위를 가지는 현시에 대해 진행 신호를 부여하고 나머지는 대기한다. 진행 신호의 시간은 교차로에 대기하는 모든 차량의 수와 진행 신호를 부여받은 현시의 차량의 수를 이용하여 계산한다. 본 논문에서 제안된 퍼지 신호 제어 기법과 정적인 신호 제어 기법에 대해 시뮬레이션을 통해 실험한 결과, 차량 혼잡도와 상관없이 제안된 차량 신호 제어 기법이 동일한 시간에 더 많은 차량이 원활하게 소통되는 것을 확인하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권4호
• /
• pp.359-366
• /
• 2007

Purpose: In spite of various advantages of hyaluronic acid in wound healing, there are few research about wound healing process and period in oral and maxillofacial surgery. So, We evaluated the effects of local application of hyaluronic acid gel on wound healing of the oral mucosa using this animal model. Materials and methods: Young adult New Zealand White rabbits, weighting between 2.5 and 3.0kg, were used. Almost uniform round ulcers could be created on the gingival of the rabbits by chemical injury with acetic acid. In experimental group, hyaluronic acid gel was applied daily until the wounds healed and in control group, ulcer lesion was not any treatment. The lengths of ulcers were measured the longest and shortest axes of the ulcers and calculated the areas of ulcer. For histological examination, specimens were made, and observed under a light microscope. Results: The results showed that the number of fibroblasts, new blood vessels and the epithelial thickness from experimental group was higher than from control group. Hyaluronic acid promoted proliferation of the fibroblast, keratinocytes isolated from gingival tissue of rabbits in vitro. Topical application of hyaluronic acid accelerated healing of ulcers created in rabbits. Conclusion: The hyaluronic acid may be effective for wound healing of oral mucosal lesions.

• Nuclear Engineering and Technology
• /
• 제19권1호
• /
• pp.34-41
• /
• 1987

본 논문은 부하추종운전노심의 1차원 해석방법과 3차원 해석방법을 비교하기 위한 것이다. 이 목적으로 본 논문에서는 유한차분법에 의거한 1차원 HLOFO 코드와 수정형 Borresen 소격모형에 의한 3차원 CMSNAC 코드를 개발했다. CMSNAC 코드는 100-50-100% 출력변화를 수반하는 12-3-6-3 부하추종운전에 대한 고리 1호기 노심의 3차원 출려분포와 반응도 변수를 계산하는데 이용했다. 3차원 계산결과는 중성자속.체적 가증법으로 구한 단면적 및 버클링 입력에 의거한 1차원적 HLOFO 계산결과와 비교되었으며, 이 비교로부터 1차원 HLOFO 계산이 정착도 면에서 다소 뒤떨어지지만 3차원 계산에 가까운 결과를 얻을 수 있다는 것을 보였다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제14권1_2호
• /
• pp.65-76
• /
• 1992

This study was designed to observe the adaptive changes of mandibular condyles to displacement of mandibular condyle in adult animals. In this study, 16 rabbits weighting about 3.5 kg was selected. Four rabbits were preserved for control group and 8 animals were divided into 3 groups, 2 weeks, 4 weeks and 8 weeks. The experimental animals were performed oblique osteotomy on both mandibular ramus and internal wiring at mandibular border. The experimental animals were sacrificed consecutively on the 2 weeks, 4 weeks and 8 weeks after oblique osteotomy and mandibular condyles were dissected out carefully to produced tissue specimen. The specimens were fixed with 10% N formaline solution for 24 hours and rinsed with phosphate buffer solution. It was decalcified with 5% nitric acid for 15 days. Thereafter the specimens were dehydrated in alcohol series and embedded paraffin as usual manner. The mebedded specimen were sectioned in $4-6{\mu}m$ microtome, stained with hematoxylin-eosin and azan stain and observed through light microscope. The following results were observed from this experiment. When there was postional change of condyle head after mandibular ramus oblique osteotomy in adult rabbit, 1. The density of chondrocyte was generally increased at condylar cartilage and the thickness of condylar cartilage was increased posterosuperior aspect of the mandibular condyle slightly. 2. The density of chondrocyte was increased at proliferative zone so fibrous articular zone, porliferative zone and hypertrophic zone was clearly distinguished. 3. Active endochondral bone formation was occurred at mandibular condyle.