• 방송공학회논문지
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• 제19권4호
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• pp.453-467
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• 2014

일반적인 히스토그램 평활화는 화질향상을 위한 명암대비 향상 효과가 뛰어나다. 하지만 과도한 밝기 값의 변화가 나타나기 때문에 영상의 평균밝기가 프레임 단위로 변화하는 TV와 같은 동영상 응용분야에 적용하기에는 부적합하다. 이러한 단점을 해결하기 위하여 히스토그램 평활화의 변형된 방법에 대한 다양한 연구가 이루어져 왔다. 그러나 기존의 방법들은 과포화현상(over-enhancement), 계조 현상(false-contouring)과 같은 화질 열화를 보인다. 본 논문에서는 차별적 히스토그램 압축방법을 기반으로 하는 목표 평균 밝기값을 이용한 분할 히스토그램 평활화를 통해서 개선된 명암대비 향상 기법을 제안한다. 제안한 방법은 평균 밝기값을 기준으로 히스토그램을 분할하고, 각 영역에 대해 히스토그램을 빈도수에 따라 차별적으로 압축한다. 그리고 변형된 히스토그램을 목표 평균 밝기값 기준으로 평활화한다. 이를 통하여 화질 열화를 억제하고, 동영상의 각 프레임의 평균밝기 변화를 유지하면서 명암대비를 개선시킨다. 실험 결과 제안방법은 기존 방법에 비해 동영상에서 각 프레임의 평균밝기를 잘 유지하고, 화질 열화 없이 좋은 명암대비 향상 효과를 보였다.

• Archives of Plastic Surgery
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• 제36권6호
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• pp.773-778
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• 2009

Purpose: The authors propose the new classification of fatty - type gynecomastia(lipomastia) which can serve as a guide for modifying the periareolar technique. Methods: A retrospective analysis was made of 1000 cases of lipomastia operated on in the last 17 months. The extent of the clinical result, the technique employed, and the complications were observed. On the basis of this review the authors observed that at grade I(fat component < 50 ml, fibroglandular component < 3 g each breast), flattening of the thorax can be achieved by means of stab incision, ultrasound - assisted lipectomy(UAL), scavenging suction - assisted lipectomy(SAL) and tissue shaving. At grade II(50 < < 150 ml, 3 < < 5 g), stab incision, UAL, SAL and pull - out method(POM) using small curved scissors. At grade III(150 < < 300 ml, 5 < < 15 g and prominent inframammary fold(IMF)), minimal incision (5 - 6 mm), UAL, SAL and POM using small angulated scissors, and blunting IMF. At grade IV (300 < < 500 ml, 15 < < 30 g, and glandular ptosis), minimal incision (5 - 6 mm), UAL, SAL, fibroglandular excision using small angulated scissors, cutting IMF and fixation of nipple - areola complex(NAC) becomes necessary. At grade V (> 500 ml, > 30 g and ptosis), small incision (7 - 8 mm), UAL, SAL, fibroglandular excision using large angulated scissors, cutting IMF, upper repositioning of NAC and delayed circumareolar skin reduction or chest lifting becomes necessary. Results: The complications were minimal but there were hematoma (n = 7), infection (n = 3) and hypertrophic scar (n =13). Almost patients were satisfied with the outcome. Conclusion: This simple classification may help in choosing the most suitable treatment, thus avoiding insufficient or invasive treatments and undesirable scars.

• Journal of International Society for Simulation Surgery
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• 제1권2호
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• pp.71-74
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• 2014

Purpose The prominent mandible angle, otherwise known as "square face", has been recognized as an aesthetic problem that needs correction by many in the Asian community. Many surgeons considered that mandible angle ostectomy alone, brings about hypotrophy of the masseter muscle. However, it was only proven indirectly (by clinical experience and histological animal experiments) and not objectively. In this study, we evaluated the volume of masseter muscle to prove the effect, objectively. Materials and method Computed tomography (CT) images were used to measure the masseter muscle volume of normal female group (n=6), and of female patient group n=8, preoperative and early & late postoperative volumes) presenting the symptom of prominent mandible angle. The data was analyzed statistically by two-sample t-test and paired t-test using SAS (version 8.2). Results In normal female group, volume average was $16,142{\pm}2,829.8mm^3$. In patient group, preoperative volume averaged $24,447{\pm}4,544.5mm^3$ (p<0.0001), early postoperative volume measured average of $31,966{\pm}50,421mm^3$ which is a 30% increase from the preoperative volume (p<0.0001). Late postoperative measurement was $20,202{\pm}4,092.3mm^3$, which is a 20% decrease from the preoperative volume (p<0.0006). Conclusion The bone reduction of prominent mandible angle induce the hypotrophic effect of masseter muscle after long term follow up (5 more months). This result mean that the result of mandible angle contouring surgery can be considered as combined effect of bony angle reduction and subsequent masseter muscle hypotrophy.

• Archives of Reconstructive Microsurgery
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• 제12권2호
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• pp.99-104
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• 2003

Liposuction is a useful method for debulking free flap. Recently, ultrasound assisted liposuction(UAL) has been reported to have many advantages over conventional suction-assisted lipectomy. We applied the UAL to debulk free fasciocutaneous flap of the forehead and lower extremities. The result was satisfactory and there was no significant complications worth noting. Although the cost can be expensive, it has many advantages such as less blood loss, larger amount of fat aspirate and better skin contraction. We can conclude that UAL can be a useful alternative method to debulk free fasciocutaneous flap.

• 제어로봇시스템학회논문지
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• 제3권4호
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• pp.389-397
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• 1997

In this paper, we propose a new method of contour error modeling for cross-coupled control of CNC machines. This modeling method is based on the information that the interpolator of a CNC machine generates knot points per each sampling time in order to approximate a given curved path as a series of small straight-line segments. The merits of the proposed method are : (1) its applicability for arbitrary curved contours and (2) its ability to calculate contour errors more accurately than the other conventional methods. The proposed method is evaluated and compared with the conventional methods using the three typical curved trajectories by computer simulations. Furthermore, it is shown that the cross-coupled controller based on this proposed error model improves contouring accuracy more effectively than the other methods.

• 대한기계학회논문집
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• 제6권4호
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• pp.341-345
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• 1982

The interpolator is usually built in hardware (logic circuitry), and the interpolator fabricated in a single LSI chip is recently made use of in most NC controllers, making the system more compact. However, the LSI interpolator not only has the technical difficulties but also requires high cost, in its fabrication. To solve these problems, we tried to find the method of interpolation by software, and succeeded in developing a program which, executed by INTEL's 8085 microprocessor, can distribute the input pulses of up to 4.0 [Kpps] for the linear interpolation and 3.0 [Kpps] for the circular interpolation. This paper presents the algorithm used to reduce the execution time and the flow chart of the interpolation program, and also shows the possibility of software interpolation. The interpolation program designed in assembly language is presented in the appendix.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권5호
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• pp.473-479
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• 2008

Asians tend to have prominent mandibular angle. The causes of wide lower third of the facial contour are obtuse mandibular angle and hypertrophy of masseter muscles. In cases of hypertrophy of masseter muscles, conventional treatment intends to the contraction of masseter muscle. Recently, volumetric reduction of masseter muscles using botulinum toxin type A injection and radiofrequency (RF) reduction have been introduced. The use of RF energy for masseter muscle reduction is known as a safe, simple, and effective method for aesthetic lower facial contouring. The purpose of this study is to present the effects of RF reduction applied to hypertrophy of masseter muscles, to review and to encourage RF practices in oral and maxillofacial region.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.535-538
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• 2006

The Objective of this study is to document the three-dimensional flow in a turbine cascade with Contoured endwall in terms of Stanton number distribution to proposes an appropriate contraction ratio of endwall contouring which show the best performance. This study was numerically performed. The results show that heat transfer coefficient on the contoured endwall which has the height of 15% of the axial chord showed best performance. The numerical method and results in this study can be applied to the design of gas turbine cascade with high performance.

• 대한치과의사협회지
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• 제12권5호
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• pp.339-344
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• 1974

The authors conducted a study of theoritical background and clinical application of the transitional denture with one subject at The Ohio State University, Graduate School. The applicability of this method is considered to be not so great, however, it is likely to be a advantageous way of approaching to the prospective denture patients with severe periodontal diseases. Especially, in this transitional denture technique, natural teeth are duplicated to reject the development of abnormal oral physiology and some effects occuring during edentulous period. As a result of the minimal surgery and protective measure of denture contouring and tissue conditioning, the transitional denture may show treatment effects to the dentrue surrounding tissues and basal seat tissues.

• 한국대기환경학회지
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• 제31권2호
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• pp.97-104
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• 2015

The pollution of particulate matter (PM) is considered one of the hot socioenvironmental issues at present time. In this study, we investigated the distribution of fine particulate matter ($PM_{2.5}$) in Wangsimni commercial areas in Seoul, Korea to learn more about its environmental behavior in an urban area. Our analysis of $PM_{2.5}$ was made to distinguish the $PM_{2.5}$ pollution levels between three different types of site characteristics: (1) densely populated area, (2) thinly populated area, and (3) traffic roadside. Moreover, to assess the temporal trends in our study, the concentration levels of $PM_{2.5}$ were also compared between weekdays and weekends and between early in the afternoon and evening. The average concentration of $PM_{2.5}$ from densely and thinly populated areas were measured as $36.0{\pm}13.1$ and $32.3{\pm}11.2{\mu}g/m^3$, respectively. If the results are compared between different time bands, there were apparent differences between weekdays ($29.6{\pm}10.8{\mu}g/m^3$) and weekends ($36.9{\pm}12.1{\mu}g/m^3$). Such difference was also evident between noon ($27.8{\pm}5.8{\mu}g/m^3$) and evening ($38.3{\pm}13.7{\mu}g/m^3$). According to our research, concentration of $PM_{2.5}$ in the study area was affected more sensitively by time zone rather than the population density. The measurement data was also analyzed by drawing concentration map of $PM_{2.5}$ in the Wangsimni commercial areas based on data contouring method.