• Advances in pediatric surgery
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• v.11 no.2
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• pp.131-140
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• 2005

The purpose of this study is to review the operative management and outcome of operation for Crohn's disease. The medical records of 17 patients who underwent operations for Crohn's disease at Seoul National University Children's Hospital from January of 1988 to June of 2005 were reviewed. The male-to -female ratio was 1.8: 1. The median age at the onset of symptoms and the time of diagnosis was 9 years 6 months and 11 years 6 months respectively. The median time interval from diagnosis to operation was 2 years and 1 month (0 month~8 years). The ileocolic or ileocecal region was the most common site of involvement. The indications for operation were intractable symptoms (8 cases) and obstruction or stricture (7 cases). The median postoperative hospitalized days were 14.4 days (8~35 days). Five patients (29 %) experienced postoperative complications. Symptom free state or symptom relief was observed in 11 cases after surgery and 6 cases had intermittent episodes of remissions and recurrences. In pediatric Crohn's disease patients who present with intractable symptoms despite medical treatment or develop surgical complications, symptom free state or symptom relief can be achieved by minimal resection of the diseased segment.

• Clinics in Shoulder and Elbow
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• v.4 no.1
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• pp.17-23
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• 2001

There has been considerable controversy concerning the methods for treatment of dislocation of the acromioclavicular joint, especially in grade III injury. The authors have treated 24 cases of the complete dislocation of the acromioclavicular joint from January 1990 to July 2000. We performed 14 cases of coracoclavicular wiring operation, 10 cases of modified Phemister operation and compared the results and complication of wiring operation with modified Phemister. The clinical results in modified phemister operation were excellent in 8 cases(80%), good in 1 case(l0%), fair 1 case(10%). In wiring operation, excellent is 11 case(78%), good is 2 case(14%), fair is 1 case(14%). The complications of modified Phemister operation were breakage and migration of K-wire in 2 cases. In wiring operation, breakage of wire was in 2 cases but migration was not showed. We prefered coracoclavicular wiring operation for dislocation of acromioclavicular joint of active young adults because of the following advantages: 1) violation of acromioclavicular joint can be avoided but rotation of the clavicle was not restricted. 2) The operation is simple to perform. 3) Postoperative immobilization is minimal. 4) Removal of the wire is easy because wire was not migrated when breakage of wire was occured.

• Advances in pediatric surgery
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• v.10 no.1
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• pp.1-8
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• 2004

A re-pull-through operation for Hirschsprung's disease is performed when the primary operation has failed because of the remnant or acquired aganglionosis, anastomotic stricture and/or fistula. The purpose of this study is to review our experience of the re-pull-through procedure for Hirschsprung's disease. From May 1978 to July 2003, 26 patients who underwent re-pull-through operations at the Department of Pediatric Surgery, Seoul National University Children's Hospital, were studied retrospectively by means of chart review as well as telephone interview. The mean age at primary operation and re-operation were llmonths (2 months - 10 years) and 43 months (1 year - 23 years 3 months), respectively. Initial operation for Hirschsprung's disease was Duhamel's procedure in 17, Swenson's in 6 and Soave's 3. Causes of failure of primary operation were remains of secondary aganglionic segment (n=23), vascular arcade injury (n= 1), rectoperineal fistula (n=2, due to mesenteric torsion and poor blood supply), Mean interval between the primary operation and the re-operation was 34 months (6 months-22 years). Reoperation methods were Soave's in 12, Duhamel's in 8, APSP (abdomino-posterosagittal pull-through procedure) in 5, and Swenson's in 1 case. In 2 cases of repeated rectoperineal fistula or rectourethral fistula, re-APSP were performed 3 times, respectively. A total of 29 re-pull-through operations were performed. Postoperative complications were wound infection (n=1), adhesive ileus (n=1), rectoperineal fistula (n=3), rectourethral fistula (n=2), and death due to pulmonary embolism (n=1). Mean follow up period of reoperation was 78 months (1 month-23years). In current state, 2 patients have an ileostomy because of repeated rectoperineal fistula and rectourethral fistula. Of the remaining 23 patients, 21(91 %) are totally continent with or without minimal soiling. Reoperation for Hirschsprung's disease was effective and safe for the patients complicated to the initial pull-through operation.

• Archives of Craniofacial Surgery
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• v.9 no.2
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• pp.101-104
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• 2008

Purpose: Diplopia and cosmetically unacceptable enophthalmos are the major complications of blow out fracture. Prolapse of orbital tissue into the sinuses, enlarged orbital volume, atrophy of orbital fat and loss of support of orbital walls play a role in the pathogenesis of enophthalmos. To correct post-traumatic enophthalmos, freeing of incarcerated orbital contents combined with reduction of bony orbital volume and reconstruction of suspensory support of globe is necessary. But remained enophthalmos after surgical treatment is difficult to correct completely. In this case, the authors performed implant insertion for affected orbit and endoscopic orbital decompression for unaffected orbit for correction of late enophthalmos. Method: We reviewed a girl patient with right inferomedial orbital wall blow out fracture, right zygoma fracture treated at our hospital for correction of enophthalmos. An 18-year-old female had sustained posttraumatic enopthalmos. Two surgical management was performed for correction blow out fracture at the other hospital. But residual diplopia, enophthalmos, cheek drooping were found. And then she transferred to our hospital. She had severe enophthalmos(5 mm) also had diplopia and extraocular muscle limitation. We performed operation for correction of enophthalmos. After operation, she showed minimal improvement of diplopia and enophthalmos(3 mm). The authors make plan for operation for correction enophthalmos due to cosmetical improvement. Implant insertion was performed for affected orbit. For unaffected orbit, nasoendoscopic medial orbital wall decompression was proceeded. Result: Correction of enophthalmos was found after operation and was maintained for nine years follow-up. Patient expressed satisfaction for the result. Conclusion: To correct persistant enophthalmos, we could have satisfactory result with orbital wall reconstruction on affected eye and decompression on unaffected eye.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.945-952
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• 2013

The R wave of QRS complex is the most prominent feature in ECG because of its specific shape; therefore it is taken as a reference in ECG feature extraction. But R wave detection suffers from the fact that frequency bands of the noise/other components such as P/T waves overlap with that of QRS complex. ECG signal processing must consider efficiency for hardware and software resources available in processing for miniaturization and low power. In other words, the design of algorithm that exactly detects QRS region using minimal computation by analyzing the person's physical condition and/or environment is needed. Therefore, efficient QRS detection based on SOM(Subtractive Operation Method) is presented in this paper. For this purpose, we detected R wave through the preprocessing method using morphological filter, empirical threshold, and subtractive signal. Also, we applied dynamic backward searching method for efficient detection. The performance of R wave detection is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate the average of 99.41% in R wave detection.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.195-207
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• 2007

The urban railways connecting between the inner city and suburb of Seoul metropolitan area, has lost the competitiveness against cars because too many stops deteriorated operating speed and passenger's level of service. This paper suggests that an express train should be introduced into the urban railway system in order to sort out such a complication. There are two considerations in the present study. Firstly, train schedule problem should be taken into account. In this regard, a new model for urban railway system was developed by revising the existing models dealing with single line freight railway. Approximate branch and bound algorithm based on conflict group rather than a single conflict was adopted. Consequently, it was found that the time saving in calculating the optimal schedule is the most meaningful contribution of the algorithm. The second consideration is associated with the application of the model. A case study was carried out using the actual operation data from Ansan line. In conclusion, the operation speed of the line can increase considerably with minimal number of new sidings.

• Journal of Chest Surgery
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• v.28 no.3
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• pp.297-302
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• 1995

Video-assisted thoracic surgery [VATS is emerging as a viable alternatives to thoracotomy when surgical treatment of spontaneous pneumothorax is required.Apical blebs and bullaes of the lung can be resected,and pleural abrasion can be accomplished with minimal postoperative pain and a shorter postoperative stay in hospital. We compared our results with thoracoscopic management of spontaneous pneumothorax in 20 patients [group I with a group of 32 patients previously subjected to lateral limited thoracotomy [group II . Indications for operation, sex distribution, and average age [groupI, 24.7 years ; group II, 34.4 years were comparable. Operation time [112.42 54.7 min versus 124.8 35.3 min ; P 0.03 and chest tube duration [64.4 52.3 hours versus 97.7 45.4 hours ; P 0.01 were less in group I. Postoperative hospital stay was less in group I[3.84 0.99 days;P 0.01 , as was the use of parenteral narcotics after 48 hours. [5/20=25% versus25/32=78% . Pain was quantitated by verbal rating scale in postoperative 1 to 3 days. Patients undergoing VATS experienced significantly less postoperative pain. Postoperative complication was less in group I[1/20=5% versus 3/32=8.3% . In conclusion, Video-assisted thoracoscopic management of spontaneous pneumothrax allows performance of the standard surgical procedure while avoiding the thoracotomy incision.Video-assisted thoracic surgery [VATS is safe and offers the potential benefits of shorter postoperative hospital stays and less pain with cosmetic benefits.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.89-99
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• 2007

In this paper, an analytic model of a sleep mode operation in the IEEE 802.16e is investigated. A mobile subscriber station(MSS) goes to sleep mode after negotiations with the base station(BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/l with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.833-839
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• 2018

This paper presents an analysis and the methodology of optimal operation strategy of the ESS(Energy Storage System) for reduce electricity charges. Electricity charges consist of a basic charge based on the contract capacity and energy charge according to the power usage. In order to use electrical energy at minimal charge, these two factors are required to be reduced at the same time. QP(Quadratic Programming) is appropriate for minimization of the basic charge and LP(Linear Programmin) is adequate to minimize the energy charge. However, the integer variable have to be introduced for modelling of different charge and discharge efficiency of ESS PCS(Power Conversion System), where MILP(Mixed Integer Linear Programming) can be used. In this case, the extent to which the peak load savings is accomplished should be assumed before the energy charge is minimized. So, to minimize the electricity charge exactly, optimization is sequentially performed in this paper, so-called the Two Stage Hybird optimization, where the extent to which the peak load savings is firstly accomplished through optimization of basic charge and then the optimization of energy charge is performed with different charge and discharge efficiency of ESS PCS. Finally, the proposed method is analyzed quantitatively with other optimization methods.

• Journal of Korean Neurosurgical Society
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• v.45 no.1
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• pp.53-56
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• 2009

The authors present a case of subdural empyema in a macrocephalic patient. A 23-year-old male was admitted due to headache and fever. One month ago, he had mild head injury by his coworkers. Physical examination showed a macrocephaly and laboratory findings suggested purulent meningitis. Neuroimaging studies revealed a huge size of epidural space-occupying lesion. Under the impression of epidural abscess, operation was performed. Eventually, the lesion was located at subdural space and was proven to be subdural empyema. Later, histological examination of the specimen obtained by surgery demonstrated finings consistent with the capsule of the chronic subdural hematoma. Two weeks after operation, Propionibacterium acnes was isolated. The intravenous antibiotics were used for total of eight weeks under monitoring of the serum level of the C-reactive protein. Follow-up brain computed tomography (CT) scan showed the presence of significant amount of remaining subdural lesion. However, he has complained of minimal discomfort. It is suggested that the subdural empyema occurred with preexisting chronic subdural hematoma after head injury about one month prior to admission and it took a long time to treat Propionibacterium acnes subdural empyema with systemic antibiotics, at least over eight weeks.