• Korea-Australia Rheology Journal
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• v.16 no.2
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• pp.91-99
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• 2004

For the Rouse chain composed of infinite number of beads (continuous limit), conformational changes during the creep and creep recovery processes was recently analyzed to reveal the interplay among all Rouse eigenmodes under the constant stress condition (Watanabe and Inoue, Rheol. Acta, 2004). For completeness of the analysis of the Rouse model, this paper analyzes the conformational changes of the discrete Rouse chain having a finite number of beads (N = 3 and 4). The analysis demonstrates that the chain of finite N exhibits the affine deformation on imposition/removal of the stress and this deformation gives the instantaneous component of the recoverable compliance, $J_{R}$(0) = 1/(N-l)v $k_{B}$T with v and $k_{B}$ being the chain number density and Boltzmann constant, respectively. (This component vanishes for N\longrightarrow$\infty$.) For N = 2, it is known that the chain has only one internal eigenmode so that the affinely deformed conformation at the onset of the creep process does not change with time t and $J_{R}$(t) coincides with $J_{R}$(0) at any t (no transient increase of $J_{R}$(t)). However, for N$\geq$3, the chain has N-l eigenmodes (N-l$\geq$2), and this coincidence vanishes. For this case, the chain conformation changes with t to the non-affine conformation under steady flow, and this change is governed by the interplay of the Rouse eigenmodes (under the constant stress condition). This conformational change gives the non-instantaneous increase of $J_{R}$(t) with t, as also noted in the continuous limit (N\longrightarrow$\infty$).X>).TEX>).X>).

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.87.2-87.2
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• 2010

The steady and dynamic process model for an internal reforming molten carbonate fuel cell power plant is discussed in this paper. The dominant thermal and chemical dynamic processes are modeled for the stack module and balance-of-plant, including cathode gas preparation, heat recovery, heat loss (Each heat loss amount for the stack and MBOP is obtained from real plant data) and fuel processing. Based on dynamic model and control demand, PID controllers are designed in the whole system. By applying these controllers we can obtain temperature balance of stack and control system depending on changing steam to carbon ratio, air feed amount, and transient condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.220-220
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• 2009

We are developing of the evaluation technique and system for testing the performance of circuit breaker using Simplified Synthetic circuit. This facility specification is up to 90[kApeak] and up to 300[kVpeak]. It is possible to verify the interrupting capability by using low-energy and reduce the development period and the cost.

• ETRI Journal
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• v.31 no.5
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• pp.631-633
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• 2009

We introduce an improved Ethernet ring protection method, selective filtering database (FDB) advertisement, to minimize traffic overshoot in the event of a failure or recovery. On the protection switching event, the proposed method makes all ring nodes perform an FDB flush except the FDB entries associated with their client subnets. Then, ring nodes rapidly exchange their client MAC address lists so that their FDBs are immediately updated by indirect MAC address learning. The proposed scheme guarantees fast and reliable protection switching over the standard scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1122-1129
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• 2007

For a system with multiple real-time tasks of different deadlines, it is very difficult to find the optimal checkpoint interval because of the complexity in considering the scheduling of tasks. In this paper, we determine the optimal checkpoint interval for multiple real-time tasks that are scheduled by RM(Rate Monotonic) algorithm. Faults are assumed to occur with Poisson distribution. Checkpoints are inserted in the execution of task with equal distance in the same task, but different distances in other tasks. When faults occur, rollback to the latest checkpoint and re-execute task after the checkpoint. We derive the equation of maximum slack time for each task, and determine the number of re-executable checkpoint intervals for fault recovery. The equation to check the schedulibility of tasks is also derived. Based on these equations, we find the probability of all tasks executed within their deadlines successfully. Checkpoint intervals which make the probability maximum is the optimal.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.122-124
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• 2003

전기설비 중 차단기와 개폐기는 전기회로를 개폐하는 기기들이다. 차단기가 단락사고에 대한 주회로 보호가 목적이라면 개폐기는 건전회로의 개폐가 주요한 기능이다. 저압용 전자개폐기는 빈번한 개폐사용조건으로 인해 시험규격에서는 수천회에서 수만회까지 개폐시험을 통해 성능을 검 중하도록 되어 있고 배선용 차단기는 차단 시험과 개폐시험을 통해 성능을 검증하도록 규정되어 있다. 이 개폐시험 회로와 단락차단 시험회로는 규정된 전압, 전류, 역률조건을 맞추기 위해 저항과 리액터를 직렬 연결하여 구성한다. 개패시험과 단락차단시험을 진행하는 동안 시료 접점 사이에는 성능에 치명적인 과도한 회복전압이 발생한다. 따라서 규격에서는 과도회복전압을 적합한 수준으로 줄이기 위해 리액터 양단에 병렬로 고저항을 설치하도록 제안하고 있다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.76-79
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• 2000

Polymeric composites exhibit highly nonlinear and rate dependent behavior during loading and unloading in off-axis directions. The equilibrium state of stress during loading is lower than the state of stress produced at finite strain rates. The amount of stress relaxation during loading decreases. Interestingly, however, the stress goes up to reach to the equilibrium state of stress for a fixed displacement during unloading. The unloading behavior is quite similar to the loading behavior. The stress relaxation patterns during loading and unloading is also similar, and those depend on the fiber orientation angles and the loading and unloading rates. The AS4/PEEK thermoplastic composite is used to characterize the relaxation behavior for different off-axis angles and loading rates. There exists a transient loading region at the beginning of unloading. The effective stress and effective plastic strain concept is used to establish a master curve of stress recovery pattern for different off-axis angles and unloading rates.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.184-188
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• 2001

Horner's syndrome as a complication of orthognathic surgery is given little attention of head and neck surgery and is a relatively benign and transient condition. A 18-year-old male referred to our department with long and anteriorly projected chin. The cephalometric evaluation revealed a skeletal Class III relationship. A 10-mm setback of the mandible to eliminate Class III relationship and 4-mm vertical reduction genioplasty were performed. Three weeks after operation, the patient was recognized anhidrosis in left face and the head, and ptosis of left eye. The trauma to cervical sympathetic nerve during left sagittal split ramus osteotomy was thought to be the cause of Horner's syndrome. Patient was treated by dermatologic and opthalmologic care. Follow-up examination 8 months later, he was recovery of horner's symptom.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.162-168
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• 1990

Unroofed coronary sinus syndrome is an uncommon anomaly which is caused by incomplete formation of the left atriovenous fold and it is usually associated with persistent left superior vena cava. It may be diagnosed by cardiac catheterization and cineangiography but, if it is not diagnosed, it can bring out significant complications due to right to left shunt, such as brain abscess, cerebral embolism, transient ischemic attack, arterial desaturation and there will reduced patient`s life expectancy. Therefore corrective operation was needed. A case of unroofed coronary sinus syndrome which combines with valvular heart disease was experienced at the department of thoracic & cardiovascular surgery of Kosin medical college. The patient was 49 years old female and she complained dyspnea on exertion for 2 yrs. Cardiac catheterization with cineangiography and both superior venacavogram were performed for diagnosis and she was diagnosed as unroofed coronary sinus syndrome combined with mitral and tricuspid regurgitation. Surgical correction was accomplished by reroofing of coronary sinus with pericardial patch, closure of atrial septal defect and annuloplasty of both atrioventricular valves. Postoperative results were satisfactory and course of recovery was uneventful. We report a case of unroofed coronary sinus syndrome with review.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.172-174
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• 2008

A fault current limitation using fault current limiter(FCL) is very important for power system operation. In recent year, a number of research have been performed and still Progressing about the super conducting fault current limiter(SFCL), To protect the power system effectively from the large fault current, several superconducting fault current limiters proposed. However, there are many problem such as cost, recovery and ac loss. To solve these problems, hybrid superconducting fault current limiter(HSFCL) have been proposed. In this paper, HSFCL are modeled using (Electro Magnetic Transient Program - Restructured Version) EMTP-RV.