• Archives of Reconstructive Microsurgery
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• v.8 no.1
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• pp.84-91
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• 1999

The female breast is a potent symbol of maternity, sexuality, and feminity. Unfortunately, the frequency of breast cancer and mastectomy are increasing in Korea, so the reconstruction of breast becomes a important surgical procedure. The purpose of this study is to analyze the results of breast reconstruction using free TRAM flap and to suggest the operative techniques for more successful results. This study is based on a series of 39 cases of breast reconstruction using free TRAM flap in mastectomized patients. Among these cases, 21 patients underwent immediate reconstruction and 18 patients underwent delayed reconstruction. 2 patients underwent immediate bilateral reconstruction. The postoperative courses of these cases are uneventful. Breast reconstruction following mastectomy is one of the most challenging problems in plastic surgery. Nowadays the free TRAM flap is accepted as an excellent method of autogenous tissue breast reconstruction. We conclude that this technique has advantages as follows. The free TRAM flap has not associated with the complications of implant-based reconstruction. It provides sufficient volume for ptotic and natural breast, easily concealed donor site, and secondary aesthetic benefit of abdominoplasty. Unlike conventional pedicled TRAM flap, it has superiority in blood supply, and can make liberal setting of flap and sparing of rectus muscle. So it can provide more satisfaction about the final result of breast reconstruction.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.14-24
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• 2011

In order to facilitate the electricity market operation and trade in the restructured environment, ample transmission capability should be provided to satisfy the demand of increasing power transactions. The conflict of this requirement and the restrictions on the transmission expansion in the restructured electricity market has motivated the development of methodologies to enhance the available transfer capability (ATC) of existing transmission grids. The insertion of flexible AC transmission System (FACTS) devices in electrical systems seems to be a promising strategy to enhance single area ATC and multi-area ATC. In this paper, the viability and technical merits of boosting single area ATC and multi-area ATC using Thyristor controlled series compensator (TCSC), static VAR compensator (SVC) and unified power flow controller (UPFC) in single device and multi-type three similar and different device combinations are analyzed. Particle swarm optimization (PSO) algorithm is employed to obtain the optimal settings of FACTS devices. The installation cost is also calculated. The study has been carried out on IEEE 30 bus and IEEE 118 bus systems for the selected bilateral, multilateral and area wise transactions.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.467-475
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• 2009

Congestion management is one of the technical challenges in power system deregulation. This paper presents single objective and multi-objective optimization approaches for optimal choice, location and size of Static Var Compensators (SVC) and Thyristor Controlled Series Capacitors (TCSC) in deregulated power system to improve branch loading (minimize congestion), improve voltage stability and reduce line losses. Though FACTS controllers offer many advantages, their installation cost is very high. Hence Independent System Operator (ISO) has to locate them optimally to satisfy a desired objective. This paper presents optimal location of FACTS controllers considering branch loading (BL), voltage stability (VS) and loss minimization (LM) as objectives at once using GA. It is observed that the locations that are most favorable with respect to one objective are not suitable locations with respect to other two objectives. Later these competing objectives are optimized simultaneously considering two and three objectives at a time using multi-objective Strength Pareto Evolutionary Algorithms (SPEA). The developed algorithms are tested on IEEE 30 bus system. Various cases like i) uniform line loading ii) line outage iii) bilateral and multilateral transactions between source and sink nodes have been considered to create congestion in the system. The developed algorithms show effective locations for all the cases considered for both single and multiobjective optimization studies.

• Journal of Chest Surgery
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• v.23 no.5
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• pp.887-893
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• 1990

We have experienced 142 cases of spontaneous pneumothorax from January 1987 to June 1990 at the department of Thoracic and Cardiovascular Surgery, Inha General Hospital, Inha University College of Medicine. The age of patients ranged from 16 to 79 years \ulcornerold. The incidence was highest between late 2nd and 3rd decades in non tuberculous group. Males occupied 110 cases [77.6%] and females 32 cases [22. 5%], and its ratio was 3.4: l. The incidence of right side pneumothorax was 76 cases [53.5%] and left side was 65 cases [45.8%]. There was one case of bilateral pneumothorax. The most common chief complaints were chest pain and dyspnea. The associated pulmonary lesions were pulmonary tuberculosis, active or healed in 51 cases [35.9%], Subpleural bleb in 19 cases [13.4%], emphysematous bulla in 12 cases [13.4%], asthma in 3, bronchiectasis in 3, pneumonia in 1, cyst in 1. The unknown origin pneumothorax, so called "idiopathic spontaneous pneumothorax”, which seemed to be caused by the rupture of bleb or bulla most likely, were 52 cases [36. 6%] in our series. Generally, closed [tube] thoracotomy with underwater sealed drainage is the treatment of choice in spontaneous pneumothorax. We experienced 94 cases[66.2%] which were cured by closed thoracotomy. However, open thoracotomy and adequate surgical procedures were undertaken in patient with continuous air leakage or recurrent attacks of spontaneous pneumothorax in 48 cases [33.8%]. The minithoracotomy is a good procedure for the bullectomy of upper lobe.lobe.

• Journal of Chest Surgery
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• v.45 no.6
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• pp.351-367
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• 2012

This second report in the series on coronary artery bypass presents the authors experience and personal views on the internal thoracic artery (ITA) which date to 1966. There has been a very gradual evolution in the acceptance of this conduit which was initially compared with the saphenous vein and viewed as an improbable alternative to it. As is common with concepts and techniques which are 'outside the box' there was skepticism and criticism of this new conduit which was more difficult and time consuming to harvest for the surgeon who had to do it all. It was viewed as small, fragile, spastic and its flow capacity was questioned. Only a few surgeons employed it because of these issues and some of them would frequently graft it to the diagonal artery as it was thought not to supply adequate flow for the left anterior descending unless it was small. After a decade, angiographic data revealed superior patency to vein grafts. Even this evidence and survival benefit reported a few years later did not convince many surgeons that their concerns about limitations justified its use. Thus widespread adaption of the ITA as the conduit of choice for the anterior descending required another decade and bilateral use is only now expanding to more than 5% of patients in the US and somewhat faster in other countries.

• Journal of Chest Surgery
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• v.28 no.2
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• pp.131-135
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• 1995

Fifteen patients[10 female and 5 male from 13 to 73 years of age[mean age 46 years underwent excision of atrial myxomas between 1981 and 1993 at the Chonnam University Hospital. Fourteen patients presented with exertional or resting dyspnea, six with palpitation, five with systemic embolization, and three with syncope. Symptoms were present from 1 week to 14 months before operation. Fourteen tumors originated from the atrial septum of left atrium and one of bilateral atrium. All tumors were pedunculated; tumor sizes were variable from 2x1x1cm to 7x6x5cm. No ventricular tumors identified. The myxomas were successfully removed in all patients, either by shaving them from the atrial septum[n=7 or excising a portion of normal atrial septum with the tumor and ASD patch closure[n=8 . There was no perioperative or late death in our experience. Follow-up is current and complete in all cases[range 6 months to 13 years . Thirteen patients are in New York Heart Association Class I, and the remaining two patients are in Class II. One recurrent left atrial myxoma was identified at 20 months after operation. In this series, excellent results were obtained by simple excision of the tumor, with or without a margin of normal atrial septum. Long-term clinical & echocardiographic follow-up is recommended since late recurrence, although rare, has been reported.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.2
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• pp.102-108
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• 2015

In surgery for facial asymmetry, mandibles can be classified into two types, rotational and translational, according to the required mandibular movements for surgery. During surgery for rotational mandibular asymmetry, a bilateral sagittal split ramus osteotomy (BSSRO) may cause a large bone gap between the proximal and distal segments as well as condylar displacement, resulting in a relapse of the temporomandibular joint disorder, especially in severe cases. The intraoral vertical ramus osteotomy has an advantage, in this respect, because it causes less rotational displacement of the proximal segment on the deviated side and even displaced or rotated condylar segments may return to their original physiologic position. Unilateral intraoral vertical ramus osteotomy (UIVRO) on the short side combined with contralateral SSRO was devised as an alternative technique to resolve the spatial problems caused by conventional SSRO in cases of severe rotational asymmetry. A series of three cases were treated with the previously suggested protocol and the follow-up period was analyzed. In serial cases, UIVRO combined with contralateral SSRO may avoid mediolateral flaring of the bone segments and condylar dislocation, and result in improved condition of the temporomandibular joint. UIVRO combined with contralateral SSRO is expected to be a useful technique for the treatment of rotational mandibular asymmetry.

• Journal of Distribution Science
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• v.13 no.7
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• pp.11-18
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• 2015

Purpose - This paper reviews the changes in the ship export and import structure between Korea and China. It utilizes the comparative advantage trade theory to analyze time-series statistical data from the market share index, revealed comparative advantage index (RCA), and trade specialization index(TSI). Research design, data, and methodology - Based on their economic phases, both Korea and China have similar country characteristics. The purpose of this research is to understand the two country's trade structures to fortify the Korea-Sino economic relationship including verifying what is working and what is not. Results - Based on the analysis, bilateral economic activity to achieve a plus trade stimulus environment should be realized in the long run. Both countries should establish guarantee-free trade negotiations and boundaries instead of various non-tariff barriers. Conclusion - Reviewing the research, a sound competitive relationship can be grown for mutual benefit including export market diversification in the near future. The review of the Korea-Sino ship industry is keenly important and investigative research about it is timely because it is a major industry in each country.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.618-626
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• 2011

Solar cell is one of the most important new renewable energy for future energy generation. This paper presents a novel two stage DC/DC converter topology for PV PCSs. The proposed converter consists of an interleaved boost converter and a two-tank LLC resonant converter which is connected in parallel in primary and series in secondary. The main idea of this topology is that the system can achieve either unilateral or bilateral operations due to the input voltage level of the PV module, which leads to a better performance. The operating schemes on the proposed converter are analyzed and described. A 2.2kW prototype product is built, tested and verified.

• Journal of Chest Surgery
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• v.1 no.1
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• pp.61-68
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• 1968

In the 10 years from 1958 through 1968, 23 patients have undergone 24 times of operation for constrictive pericarditis at this department. Follow-up data were available for periods varying several months to almost 10 years from examination at this department or follow-up letters. There were 21 males and 2 females in this series. Range of the age varied from 2 years to 53 years. Seven cases were below 15 years of age. There were two hospital death, one expired two weeks and another four weeks after the pericardiectomy. In both of them, myocardial damage by disease process seemed to be major contributing factors. Clinical and histological study showed tuberculous origin in 12 cases, non-specific chronic infiammatory changes in 8 cases and in 3 cases previous pyogenic pericardial infection by staphylococcus preceded to the constriction. In 11 cases bone tissue was noted microscopically in the pericardium: Sixteen patients[70 %]had pleural effusions, five cases had bilateral, 6 right, and 5 left. Calcification was seen along cardiac border in 9 cases. In 15 catheterized patients, 6 showed pressure gradients between vena cava and right atrium, ranging from 6 mmHg to 10 mmHg. One case was reoperated 3 months after the original operation resulting in marked improvement. In this reoperated case the original pericardiectomy seemed to be incomplete. In 21 cases. excluding 2 hospital death, symptoms and physical findings improved markedly in every patient