• Journal of Chest Surgery
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• 제26권3호
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• pp.224-227
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• 1993

We experienced one case of orthotopic cardiac transplantation in a patient with end stage dilated cardiomyopathy. This 50 year-old female recipient was suffered from NYHA functional class IV cardiac failure and dependent upon intravenous inotropic support for 2 months [recipient category 1]. Her preoperative condition was grave with left ventricular ejection fraction of 20% and estimated systolic pulmonary arterial pressure [from Doppler study] was 50mmHg. The brain-dead donor was 31 year-old male with head trauma. The body sizes [weight, height] of the donor/recipient were 70 Kg, 165 cm / 43 Kg, 160 cm and appropriately overmatched. Preoperatively, identical ABO/Rh blood group [A+] and nonreacting HLA crossmatching were confirmed. On November 11 1992 cardiac transplantation was performed without complication. Multiple organ procurement team and heart transplantation team were organized the operation schedule appropriately to minimize the ischemic time. The pump time was 126 minutes and aortic crossclamping time of recipient heart was 73 minutes and, as a result, total ischemic time of the transplanted heart was 75 minutes. Postoperatively, the vital signs were stable with minimal inotropic support. The immunosuppressive therapy was commenced from preoperatively and cyclosporine, azathioprine, and corticosteroid were used as a combination therapy as scheduled and monitored with blood drug concentration, WBC count, renal function and most importantly regular endomyocardial biopsy.Now, 5 months after transplantation, the patient is in NYHA functional class II with minimal cardiac drug support.

• Journal of the Korean Society of Safety
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• 제34권1호
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• pp.14-20
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• 2019

This paper presents a safety assessment based approach for the safe operation for PCS(Power Conditioning System) of photovoltaic and energy storage systems, applying FTA. The approach established top events as power outage and a failure likely to cause the largest damage among the potential risks of PCS. Then the Minimal Cut Set (MCS) and the importance of basic events were analyzed for implementing risk assessment. To cope with the objects, the components and their functions of PCS were categorized. To calculate the MCS frequency based on IEEE J Photovolt 2013, IEEE Std. 493-2007 and RAC (EPRD, NPRD), the failure rate and failure mode were produced regarding the basic events. In order to analyze the top event of failure and power outage, it was assumed that failures occurred in DC breaker, AC breaker, SMPS, DC filter, Inverter, CT, PT, DSP board, HMI, AC reactor, MC and EMI filter and Fault Tree was drawn. It is expected that the MCS and the importance of basic event resulting from this study will help find and remove the causes of failure and power outage in PCS for efficient safety management.

• New & Renewable Energy
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• 제20권1호
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• pp.116-125
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• 2024

Ultra-low-head is an unexplored classification among the sites in which hydroelectric power can be produced. This is typically owing to the low power output and the economic value of the turbines available in this segment. A turbine capable of operating in an ultra-low-head condition without the need of a dam to produce electricity is developed in this study. A gate structure installed at a shallow water channel acting as a weir generates artificial head for the turbine mounted on the gate to produce power. The turbine and generator are designed to be compact and submersible for an efficient and silent operation. The gate angle is adjustable to operate the turbine at varying flow rates. The turbine is designed and tested using computational fluid dynamics tools prior to manufacturing and experimental studies. A parametric study of the runner blade parameters is conducted to obtain the most efficient blade design with minimal hydraulic losses. These parameters include the runner stagger and runner leading edge flow angles. The selected runner design showed improved hydraulic characteristics of the turbine to operate in an ultra-low-head site with minimal losses.

• Archives of Plastic Surgery
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• 제40권2호
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• pp.129-133
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• 2013

Background A pneumatic tourniquet is generally used to achieve a bloodless operation field in hand surgery. However, this has changed with tumescent solution-based wide-awake surgery. This study is a preliminary prospective case series study to elaborate the formula and indications of the tumescent technique in hand surgery without a tourniquet. Methods Seven patients (age range, 4 months to 37 years) underwent hand or upper extremity surgery for conditions such as nerve palsy, electric burn defect, fingertip injury, contracture, constriction ring syndrome, or acrosyndactyly. A "one-per-mil" tumescent solution (epinephrine 1:1,000,000+20 mg lidocaine/50 mL saline) was used to create a bloodless operating field without a tourniquet. Observation was performed to document the amount of solution injected, the operation field clarity, and the postoperative pain. Results The "one per mil" epinephrine solution showed an effective hemostatic effect. The tumescent technique resulted in an almost bloodless operation field in the tendon and in the constriction ring syndrome surgeries, minimal bleeding in the flap and contracture release surgeries, and acceptable bleeding in acrosyndactyly surgery. The amount of solution injected ranged from 5.3 to 60 mL. No patient expressed significant postoperative pain. Flap surgeries showed mixed results. One flap was lost, while the others survived. Conclusions Epinephrine 1:1,000,000 in saline solution is a potential replacement for a tourniquet in hand surgery. Further studies are needed to delineate its safety for flap survival.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제29권12호
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• pp.638-644
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• 2017

Optimal cooling operation algorithm was developed based on a simulation case of a single family house model equipped with renewable energy facility. EnergyPlus simulation results were used as virtual test data. The model contained three energy storage elements: thermal heat capacity of the living room, chilled water storage tank, and battery. Their charging and discharging schedules were optimized so that daily electricity bill became minimal. As an optimization tool, linear programming was considered because it was possible to obtain results in real time. For its adoption, EnergyPlus-based house model had to be linearly approximated. Results of this study revealed that dynamic cooling load of the living room could be approximated by a linear RC model. Scheduling based on the linear programming was then compared to that by a nonlinear optimization algorithm which was made using GenOpt developed by a national lab in USA. They showed quite similar performances. Therefore, linear programming can be a practical solution to optimal operation scheduling if linear dynamic models are tuned to simulate their real equivalents with reasonable accuracy.

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.870-875
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• 2001

Objectives : Anterior tunnelling technique consist of anterior cervical fractional interspace decompression without fusion. This method provides sufficient space for adequate neuroforaminal decompression but avoids the need for fusion or fixation. We report early clinical results of 32 cases that underwent anterior tunnelling operation for treatment of cervical radiculopathy. Methods : This method is identical to conventional approach until the exposure of anterior cervical body and bilateral retraction of longus colli is made. A vertical window is then made at the vertebral bodies and disc space lateral to the insertion site of the longus colli. The window is deepened with drilling that follows a tunnelling fashion down to the compressive lesion. We analyzed clinical results from 32 patients who treated between December 1998 and August 2000. Results : Satisfactory results were obtained in 87% of the patients. Two patients required revision surgery. None revealed surgical spinal instability on last follow-up. Conclusion : Anterior tunnelling operation is an acceptable surgical option for the treatment of cervical radiculopathy. Its advantages are short hospitalization, minimal postoperative discomfort, and technical feasibility.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1890-1896
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• 2006

Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate ($q_e$), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of $2.8{\times}10^5$, $2.2\times10^5$, $1.5\times10^5$, and $1.1\times10^5$ cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was $4.3\times10^5$ cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper $q_e$ is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.

• Proceedings of the Korean Society of Computer Information Conference
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• 한국컴퓨터정보학회 2011년도 제43차 동계학술발표논문집 19권1호
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• pp.107-108
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• 2011

Since the development of railway technology, the current urban Railway the first train line in the country for safe operation control automatic/unattended operation, automatic train operation equipment available (ATO) on time and reliable operation has introduced. ATO Automatic operation controlled by the value (Target velocity) and the feedback value (Actual velocity) by the error between the backing and braking of the train by repeated low energy efficiency. In this paper, given a fixed distance stations between time operation with minimal energy in the driving characteristics and driving trains are modeled. Therefore, in line 5 real route time sectional drive straight sections for experimental data analysis / draft Section / curved and section of the train on that line is selected according to the changing driving patterns to minimize the energy optimal driving patterns were presented.

• Journal of the Korean Society of Safety
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• 제35권1호
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• pp.107-115
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• 2020

This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권4호
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• pp.349-352
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• 2001

Dental laser provides many advantages to the clinicians. Those are excellent hemostatic effect, good operating sight, minimal adjacent tissue injury, reduction of postoperative swelling & pain, reduction of postoperative infection, reduction of scar tissue & contraction, etc. The purpose of this study is to observe how these advantages work after surgical extraction of impacted third molar. From march 2000 to july 2000, we have randomly divided the patients who had been surgically extracted unilateral impacted third molar into two groups. The first group comprised $CO_2$ laser illumination with 3 watts, defocusing & continuous mode, rotating motion for about 3 minutes after finishing of surgical extraction & suture. The other group patients were not irradiated. The medications in two groups were same. We measured pain, swelling and trismus three times(pre-operation, first day after operation, and 7th day after operation). The number of the patients who had measured three times all are 64, laser irradiated groups are 36 and non-irradiated groups are 28. The age ranged from 19 to 50, with a mean of 27.9 years. The operative time ranged from 3 minutes to 50 minutes, with a mean of 12.1 minutes. In the $CO_2$ laser group, the pain intensity of the 7th day after operation was still increased significantly comparing with that of the pre-operation and the distance which were measured for the swelling was different significantly. In the other group, the mouth opening limitation was still decreased significantly.