• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.200-205
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• 2003

Purpose: To report our experiences of clinical features, treatment method and results of giant cell tumor of 5 patients in proximal fibula. Materials and Methods: Five patients managed with an en bloc resection preserving common peroneal nerve and lateral collateral ligament reconstruction with biceps femoris tendon followed up between January 1997 and July 2001. Preoperative plain radiograph and MRI and bone scan were checked. The recurrence of the tumor was judged by plain radiograph and clinical signs. Lateral instability of knee joint was checked during the outpatient follow-up. Results: The mean age of the patients at the time of operation was twenty- three (21-29). There were one male and four female patients. Dull pain was main symptom and palpable mass was seen in two patients. Peroneal nerve palsy and local recurrence were not observed except one case of temporary peroneal nerve palsy. During the outpatient follow up, one among 5 patients showed slight lateral instability and the other 4 patients showed no instabililty. Conclusion: Giant cell tumor in proximal fibula managed with an en bloc resection preserving common peroneal nerve and lateral collateral ligament reconstruction with biceps femoris tendon showed favorable results.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.27-34
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• 2011

Purpose: We examined the clinical and radiological outcomes for displaced proximal humerus fractures that were treated with a PHILOS angular stable plate. Materials and Method: Forty four patients who underwent surgery between March 2007 and February 2010 were included in this study. All the cases were followed up for an average of 12 months. All the patients were examined and interviewed using the Visual Analog Scale (VAS) score, the Constant score and standardized X-rays to check the neck-shaft angle (NSA) and the presence of medial support. Results: The average Visual Analog Scale score was 2.8 points and the average Constant score was 70.5 points. The average neck shaft angle was $122.5^{\circ}$ and this was statistically significant between the good result group and the poor result group. There were 36 cases of the presence of medial support and 8 cases of the absence of medial support and the difference was statistically significant. Complications such as fixation failure happened in 12 cases. Conclusion: PHILOS angular stable plate fixation as an operative treatment for displaced proximal humerus fractures is a good and reliable treatment option.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.968-972
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• 2005

The purpose of this study was to evaluate the effects of chitosan, which is deacetylated derivative of chitin, on the renal function. Renal dipeptidase (RDPase, membrane dipeptidase, dehydropeptidase 1, EC 3.4.13.19) is glycosyl phosphatidyl-inositol (GPI)-anchored ectoenzyme of renal proximal tubular microvilli and was related with renal disease including acute renal failure, pyelitis and nephritis. The released RDPase and Udpase activities were assayed by modified fluorometric method. In vitro experimental groups were consisted of group 1, the concentration ranges of 0, 0.01, 0.05 and $0.1\%$ chitosan only, group 2, the concentration ranges of 1, 2 and 4 mM glycerol only, and group 3, the concentration ranges of 0, 0.01, 0.05 and $0.1\%$ chitosan in the presence of glycerol (4 mM). In vivo experimental groups were consisted of group 1 in which rats were treated with glycerol for the purpose of glycerol-induced renal damage, and group 2 in which rats were treated with chitosan plus glycerol. The RDPase release of 0.01, 0.05, and $0.1\%$ chitosan groups were increased in the concentration dependent manner. The RDPase release of 1, 2, and 4mM glycerol groups were decreased in the concentration dependent manner. Chitosan in the presence of glycerol restored the released RDPase activity in the proximal tubules. In vivo, chitosan inhibited the decrease of RDPase release by glycerol in the kidney and blocked the decrease of Udpase activity by glycerol in urine. These results indicated that chitosan was possible as a functional food to control renal function and its diseases.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.11
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• pp.1424-1428
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• 1999

This paper presents a mathematical decomposition coordination method to implementing the distributed optimal power flow (OPF), wherein a regional decomposition technique is adopted to parallelize the OPT. The proposed approach is based on the Alternating Direction Method (ADM), a variant of the conventional Augmented Lagrangian approach, and makes it possible the independent regional AC-OPF for each control area while the global optimum for the entire system is assured. This paper is an extension of our previous work based on the auxiliary problem principle (APP). The proposed approach in this paper is a completely new one, however, in that ADM is based on the Proximal Point Algorithm which has long been recognized as one of the attractive methods for convex programming and min-max-convex-concave programming. The proposed method was demonstrated with IEEE 50-Bus system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.162-172
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• 2021

This paper proposes stochastic methods to find an approximate solution for the L²-Wasserstein least squares problem of Gaussian measures. The variable for the problem is in a set of positive definite matrices. The first proposed stochastic method is a type of classical stochastic gradient methods combined with projection and the second one is a type of variance reduced methods with projection. Their global convergence are analyzed by using the framework of proximal stochastic gradient methods. The convergence of the classical stochastic gradient method combined with projection is established by using diminishing learning rate rule in which the learning rate decreases as the epoch increases but that of the variance reduced method with projection can be established by using constant learning rate. The numerical results show that the present algorithms with a proper learning rate outperforms a gradient projection method.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.335-341
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• 2007

In this study, we present an approach to parallelizing OPF that is suitable for distributed implementation and is applicable to very large inter-connected power systems. The approach could be used by utilities for optimal economy interchange without disclosing details of their operating costs to competitors. It could also be used to solve several other computational tasks, such as state estimation and power flow, in a distributed manner. The proposed algorithm was demonstrated with several case study systems.

• Journal of Chest Surgery
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• v.28 no.7
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• pp.717-720
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• 1995

The bronchopleural fistula is the most common and serious complication of postpneumonectomy empyema. We experienced one case of postpneumonectomy empyema with bronchopleural fistula which treated with Abruzzini operation using residual long bronchial stump. Median sternotomy was used with extension about 3cm incision toward cephalic side. We ligated and divided the innominate vein. We did not open the pericardium with extrapericardial approach. Stapler was used to distal bronchial side and additional interupt sutures were used on proximal side.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.4
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• pp.139-143
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• 2001

Purpose : Limb salvage for osteosarcoma of proximal tibia is challenging problem due to difficulties in mobilizing or retracting the main neurovascular structure, inadequate soft tissue coverage, and unsolved problem of patellar tendon reattachment to endoprosthesis. The authors analyzed the functional result of limb salvage using tumor prosthesis with medial gastrocnemius rotation plasty for osteosarcama of the proximal tibia. Materials and Methods : Eleven patients with histologically proven osteosarcoma of the proximal tibia, treated with adjuvant and neoadjuvant chemotherapy and limb salvage operation with tumor prosthesis between January 1992 and December 1998 at our Medical Center, were selected. There were 6 male and 5 female. Age ranged from 15 years to 23.7 years with an average of 23.7 years. Follow-up period ranged from 1 year to 4.5 years with an average of 2.5 years. The final functional result was evaluated using the method by ISOLS, 1993. The factors include pain, functional activities, emotional acceptance, use of external supports, walking ability and gait. Each of the factors has been scored from 0 to 5 depending on the appropriate description or data. The rating score is determined by dividing the individual factor scores into the total score and indicates percentage of normal function. Results : The overall functional result ranged from 53,3% to 86.7% with an average of 68.3% of normal function. In details, the averages were 82.5% for pain, 62.5% for functional activities, 67.5% for emotional acceptance, 77.5% for use of external supports, 62.5% for walking ability, and 57.5% for gait. The average range of motion of the knee joint was $5^{\circ}$ extension and $85^{\circ}$ flexion. Five patients have extension lag ranged from $5^{\circ}$ to $15^{\circ}$ with an average of $10^{\circ}$. Two patients suffered postoperative infection. One was treated with antibiotics injection only, but the other needed removal of the prosthesis and knee fusion. Both of them showed unsatisfactory result. C o n c l u s i o n : The overall functional result after limb salvage using tumor prosthesis with medial gastrocnemius rotational flap for osteosarcoma of the proximal tibia was relatively satisfactory in case of no postoperative infection. The patients were less satisfactory in functional activities, emotional acceptance and gait than pain, use of external supports due to limitation of motion and extension lag. More aggressive postoperative physical therapy and protection with brace for 6~9 months as well as surgical technique is mandatory for more satisfactory result.

• Journal of the Korea Society for Simulation
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• v.33 no.2
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• pp.37-44
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• 2024

The Korean Helicopter Development Program has successfully introduced the Surion helicopter, a versatile multi-domain operational aircraft that replaces the aging UH-1 and 500MD helicopters. Specifically designed for maneuverability, the Surion plays a crucial role in low-altitude tactical maneuvers for personnel transportation and specific missions, emphasizing the helicopter's survivability. Despite the significance of its low-altitude tactical maneuver capability, there is a notable gap in research focusing on multi-mission tactical maneuvers that consider the risk factors associated with deploying the Surion in the presence of enemy air defenses. This study addresses this gap by exploring a method to enhance the Surion's low-altitude maneuvering paths, incorporating information about enemy air defenses. Leveraging the Proximal Policy Optimization (PPO) algorithm, a reinforcement learning-based approach, the research aims to optimize the helicopter's path planning. Visualized experiments were conducted using a Surion model implemented in the Unity environment and ML-Agents library. The proposed method resulted in a rapid and stable policy convergence for generating optimal maneuvering paths for the Surion. The experiments, based on two key criteria, "operation time" and "minimum damage," revealed distinct optimal paths. This divergence suggests the potential for effective tactical maneuvers in low-altitude situations, considering the risk factors associated with enemy air defenses. Importantly, the Surion's capability for remote control in all directions enhances its adaptability in complex operational environments.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.453-458
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• 2003

Usually Mylar strip and wedge or celluloid strip crown were used in conventional method of restoring proximal carious lesions of primary anterior teeth. But, these methods have some difficulties to place the matrix and wedge due to short crown lenth and interdental spacing of primary teeth. And it is difficult to form proper cavosurface margin due to the rigidity of matrix and inconvenience to support matrix by practitioner's hand in narrow oral cavity of child. This article describes an alternative technique for restoring carious lesions of primary anterior teeth using available straw. This method is very convenient and reduce chair time and it also allows good marginal adaptation.