• Archives of Plastic Surgery
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• v.47 no.2
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• pp.140-145
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• 2020

Background Capsular contracture is a common complication of two-stage expander/implant breast reconstruction. To minimize the risk of this complication, capsulectomy is performed using monopolar cautery or ultrasonic surgical instrumentation, the latter of which can be conducted with a Harmonic scalpel. To date, there is disagreement regarding which of the two methods is superior. The purpose of this study was to compare postoperative outcomes between a group of patients who underwent surgery using a Harmonic scalpel and another group treated with monopolar cautery. Methods A retrospective chart review was conducted of patients who underwent capsulectomy as part of two-stage breast reconstruction between January 2018 and February 2019 and who received at least 1 month of follow-up after surgery. Operative time and postoperative outcomes, including drainage duration, were analyzed. Results In total, 36 female patients underwent capsulectomy. The monopolar group consisted of 18 patients and 22 breasts, while the Harmonic scalpel group consisted of 18 patients and 21 breasts. There was no statistically significant difference in demographics between the two groups. The Harmonic scalpel group had a significantly shorter mean drainage duration (6.65 days vs. 7.36 days) and a smaller mean total drainage volume (334.69 mL vs. 433.54 mL) than the monopolar cautery group (P<0.05). No statistically significant difference was observed with regard to seroma or hematoma formation. Conclusions The Harmonic scalpel approach for capsulectomy reduced the total drainage volume and drainage duration compared to the monopolar cautery approach. Therefore, this approach could serve as a good alternative to electrocautery.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.466-471
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• 2004

In gas turbines, excess air for combustion is available and therefore lean premixed combustion is the most promising approach to the significant reduction of thermal NOx emissions. At lean conditions, however, flame stability is inherently worse and hence combustion tends to be incomplete. Efforts have been devoted toward extending the operating range of complete combustion at leaner conditions. One of them is the lean-lean two-stage combustion where lean to ultra-lean secondary mixtures are mixed with the hot burned gas from the primary stage. Conventional flame combustion or flameless reaction are initiated depending on the conditions of the secondary zone. In the first part of the present study, the effects of fuel injection on the emissions and flame stability were investigated for a single tubular flame, In the second part, the emissions and flame stability were studied for a two-stage combustor with secondary mixture injected through the tangential slots on a cylindrical combustor wall. The effects of the ratio of air flow rates to the primary and secondary zones on the emissions and combustion characteristics were investigate.

• ETRI Journal
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• v.33 no.3
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• pp.393-400
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• 2011

A systematic approach for the design of two-stage class AB CMOS unity-gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity-gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three design examples are fabricated in a 0.5 ${\mu}m$ CMOS process. Measurement results show slew rate improvement factors of approximately 100 for the class AB buffers versus their class A counterparts for the same quiescent power consumption (< 200 ${\mu}W$).

• Archives of Plastic Surgery
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• v.33 no.1
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• pp.53-60
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• 2006

The current authors performed two-stage ear reconstruction of microtia using autogenous costal cartilage combined with canaloplasty of the acoustic meatus in a team approach. In the first stage, lobule transposition, fabrication of the cartilage framework, and implantation of the framework were peformed. In the second stage, elevation of the auricle, cartilage graft for posterior auricular sulcus, coverage with the mastoid fascia flap and skin graft, and concha excavation were performed. The canaloplasty was combined simultaneously in patients with radiologic and audiometric evidence of cochlear function in the second stage. A total of 36 consecutive patients with congenital microtia were treated from 1998 to 2003. Among them, 27 patients(male: 18, female: 9) ranging from 7 to 43 years old were combined with canaloplasty. The follow-up period was one year to 5 years. Thirteen patients exhibited improved hearing over 30 dB PTA(pure tone average), 9 patients below 30 dB, and 5 patients with no improvement. Complications related to the canaloplasty were chronic drainages of the auditory meatus and meatal stenosis. Lobule type deformity combined with the canaloplasty showed higher complications than concha type. Therefore, in the lobule type, meticulous manipulation is necessary to reduce complications after the canaloplasty.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.424-430
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• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.445-451
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• 2002

In this paper, we propose a new tracking algorighm that achieves good tracking performance in manuevering targets while capping the computation load to "low". Kalman Filler (KF) is generally known to be poor in tracking maneuvering targets. IMM, on the other hand, compensates the weakness inherent in the mundane KF and is considered as a promising alternative for tracking maneuvering targets. However, IMM suffers from substantially increased computational load as the number of models increases. To remedy this problem, we propose a new method focused to reducing the computational load and attaining the desirable tracking performance at least as good that of IMM. It is achieved by essentially adopting the structure of IMM and injecting Optimal Two-Stage Kalman Estimator (OTSKE). The representative simulation shows a reduction in computational load with the proposed OTSKE but further reduction is shown achieved (by about 58%) with the Interacting Acceleration Compenstation (IAC)-OTSKE approach. approach.

• Journal of Korean Neurosurgical Society
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• v.43 no.1
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• pp.57-60
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• 2008

The authors herein propose the staged excision as a novel strategy to preserve facial nerve and minimize complication during microsurgery of large vestibular schwannoma (VS). At the first stage, for reducing mass effect on the brain stem and cerebellum, subtotal tumor resection was performed via a retrosigmoid craniotomy without intervention of meatal portion of tumor. With total resection of the remaining tumor, the facial nerve was decompressed and delineated during the second stage translabyrinthine approach at a later date. A 38-year-old female who underwent the staging operation for resection of her huge VS is illustrated.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.988-990
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• 1999

Using neural network approach, the diagnosis of faults in industrial process that requires observing multiple data simultaneously are studied in this paper. Two-stage diagnosis is proposed as the basic structure. The first stage detects the dynamic trend of each measurements and the second stage diagnosis the faults. This paper makes up for the disadvantage of neural about unknown faults. The potential of this approach is demonstrated in simulation using a model of tank reactor.

• Korean Journal of Remote Sensing
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• v.20 no.3
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• pp.215-225
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• 2004

A multistage hierarchical clustering technique, which is an unsupervised technique, was suggested in this paper for classifying large remotely-sensed imagery. The multistage algorithm consists of two stages. The 'local' segmentor of the first stage performs region-growing segmentation by employing the hierarchical clustering procedure of CN-chain with the restriction that pixels in a cluster must be spatially contiguous. The 'global' segmentor of the second stage, which has not spatial constraints for merging, clusters the segments resulting from the previous stage, using the conventional agglomerative approach. Using simulation data, the proposed method was compared with another hierarchical clustering technique based on 'mutual closest neighbor.' The experimental results show that the new approach proposed in this study considerably increases in computational efficiency for larger images with a low number of bands. The technique was then applied to classify the land-cover types using the remotely-sensed data acquired from the Korean peninsula.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.364-367
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• 2003

In this study, we develop a method for recognizing face images by combining wavelet decomposition, fisherface method, and fuzzy integral. The proposed approach comprises of four main stages. The first stage uses the wavelet decomposition. As a result of this decomposition, we obtain four subimages. The second stage of the approach applies a fisherface method to these four subimage sets. The two last phases are concerned with the generation of the degree of fuzzy membership and the aggregation of the individual classifiers by means of the fuzzy integral. The experimental results obtained for the CNU and Yale face databases reveal that the approach presented in this study yields better classification performance in comparison to the results produced by other classifiers.