• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.340-352
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• 2007

In this systematic review on bone reduction procedures for the correction of the prominent mandibular angle, we collected and sorted the methods. The strength and weakness, indication, complication, and final esthetic result of each method were evaluated. After searching and filtering the literatures on the base of inclusion criteria, 9 eligible case series studies were included in this study. There were 3 types of curved ostectomies and 4 types of lateral cortical ostectomies. Surgical procedures for curved ostectomies were divided into 2 types. One was single curved ostectomy and the other was multistaged curved ostectomy. Lateral cortical ostectomies reported were all similar to sagittal split ramus osteotomy. The complications reported in the included studies were scarce, but curved ostectomies may be able to induce many complications. The prominent mandibular angle must be analyzed in the lateral dimension and frontal dimension, and curved ostectomy can reduce the mandibular angle laterally while lateral cortical ostectomy can reduce the bigonial distance frontally. Because curved ostectomies can induce complications and unnaturally large mandibular angle while can not reduce bigonial distance efficiently, the current trend for the angle reduction procedure is lateral cortical ostectomies.

• 대한족부족관절학회지
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• 제14권2호
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• pp.157-160
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• 2010

Purpose: The purpose of this study is to find out the correlation factors for prognosis of calcaneal fractures. Materials and Methods: 120 cases (feet) of calcaneal fractures, all of them followed up for more than 1 year after surgical procedures, consisted of 101 men (105 feet) and 13 women (15 feet) were reviewed retrospectively. The collected clinical data were as follows : injury mechanism, surgical procedures, time to procedure, time to work and the radiologic data: Bohler angle, heel width, displacement of posterior facet. AOFAS hindfoot score and VAS score were checked. With ANOVA test and multiple regression analysis, the data processed statistically. Results: According Sanders classification, type II was 37 cases (31%), type III 66 cases (55%), and type IV 17 cases (14%). On plane radiography, the Bohler angle improved to average 28.4 degree from 5.6 degree, and the displacement of posterior facet was corrected to average 1.2 mm. AOFAS hindfoot score was checked average 81.7 points postoperatively, and the meaningful difference existed between types of Sanders classification. The Bohler angle represented the outline of the calcaneus had the better correlation with the clinical outcome of calcaneal fractures rather than the anatomical reduction of the posterior facet did. And the width of calcaneus had good correlation with the clinical score. Conclusion: We should also concern about the outline of calcaneus, the width of calcaneus and the Bohler angle representing anatomical reduction, not only the acute reduction of the posterior facet.

• Archives of Plastic Surgery
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• 제36권1호
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• pp.61-65
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• 2009

Purpose: Most nasal bone fractures involve the septum; either or both of the ethmoidal perpendicular plate(EPP) and quadrangular cartilage(QC). Unlocked tension from the underlying quadrangular cartilage and poorly reducted bony septum are obstacles to the successful reduction of nasal bone. So we compared the preliminary outcome of septoplasty as a primary treatment with the untreated septum in nasal bone fractures. Methods: We performed a retrospective study of 215 patients underwent reduction of nasal fracture between January 2002 and February 2008. We graded patients into four groups according to the amount of deviation and direction of force by CT. Our indication for septoplasty and combined procedures was the deviation of EPP or QC over 50% from the midline. We interviewed part of the patients by telephone regarding the subjective esthetic and functional outcomes. Results: Forty five of 215 patients (21 percent) underwent septoplasty and combined procedures (cartilage graft, etc) after the informed consent. Patients who underwent septoplasty significantly satisfied with the outcome of esthetic appearance and nasal patency compared with patients who underwent simple closed reduction despite of having septal deviation over 50 percent from the midline. (p < 0.05) Conclusion: Septal surgery and esthetic consideration shoud be made even in simple nasal reductions. And if CT scans reveal severe deviation of septum, septoplasty should be considered as a primary treatment.

• 한국통신학회논문지
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• 제34권11C호
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• pp.1076-1084
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• 2009

OFDM(Orthogonal Frequency Division Multiplexing) 전송 신호의 PAPR (Peak-to-Average Power Ratio)을 효과적으로 감소시키기 위하여 클리핑 잡음 (Clipping Noise)을 이용한 적응적 톤 삽입 (Adaptive Tone Injection; ATI) 기법을 제안한다. 제안된 ATI 기법은 기존 TI 방법에서의 복잡도 문제를 개선하기 위해, IFFT (Inverse Fast Fourier Transform) 출력 가운데 임계 진폭값 보다 큰 신호들을 클리핑 하는 과정, 클리핑된 신호에 대해 클리핑 잡음을 계산 후 주파수 영역 클리핑 잡음의 심벌 중에서 가장 큰 전력이 할당된 톤을 추출하는 과정, 추출된 톤을 확장된 성상도로 맵핑 후에 부분적으로 IFFT 하는 과정의 총 3단계로 구성된다. 모의실험 결과, 제안된 ATI 기법은 맵핑이 가능한 최적의 톤을 클리핑 잡음을 이용하여 추출함으로써 기존 TI 방법에서와는 달리 본래신호와 동일한 정보를 가지는 등가 신호의 가능한 모든 조합을 필요로 하지 않으며, OFDM PAPR 감소 성능 역시 최적의 TI 방법에 근접함을 보여준다.

• Nuclear Engineering and Technology
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• 제45권2호
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• pp.125-140
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• 2013

This paper aims to give an overview of the methods to inherently prevent human errors and to effectively mitigate the consequences of such errors by securing defense-in-depth during plant management through the advanced man-machine interface system (MMIS). It is needless to stress the significance of human error reduction during an accident in nuclear power plants (NPPs). Unexpected shutdowns caused by human errors not only threaten nuclear safety but also make public acceptance of nuclear power extremely lower. We have to recognize there must be the possibility of human errors occurring since humans are not essentially perfect particularly under stressful conditions. However, we have the opportunity to improve such a situation through advanced information and communication technologies on the basis of lessons learned from our experiences. As important lessons, authors explained key issues associated with automation, man-machine interface, operator support systems, and procedures. Upon this investigation, we outlined the concept and technical factors to develop advanced automation, operation and maintenance support systems, and computer-based procedures using wired/wireless technology. It should be noted that the ultimate responsibility of nuclear safety obviously belongs to humans not to machines. Therefore, safety culture including education and training, which is a kind of organizational factor, should be emphasized as well. In regard to safety culture for human error reduction, several issues that we are facing these days were described. We expect the ideas of the advanced MMIS proposed in this paper to lead in the future direction of related researches and finally supplement the safety of NPPs.

• 한국전자통신학회논문지
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• 제14권5호
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• pp.817-824
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• 2019

OFDM(Orthogonal Frequency Division Multiplexing) 전송 신호의 PAPR (Peak-to-Average Power Ratio)을 효과적으로 감소시키기 위하여 클리핑 잡음 (Clipping Noise)을 이용한 적응적 톤 삽입 (Adaptive Tone Reservation; ATR) 기법을 제안한다. 제안된 ATR 기법은 기존 TR 방법에서의 복잡도 문제를 개선하기 위해, IFFT (Inverse Fast Fourier Transform) 출력 가운데 임계 진폭값 보다 큰 신호들을 클리핑 하는 과정, 클리핑된 신호에 대해 클리핑 잡음을 계산 후 주파수 영역 클리핑 잡음의 심벌 중에서 가장 큰 전력이 할당된 톤을 추출하는 과정, 추출된 톤을 예약하여 PAPR을 감소하는 과정의 총 3단계로 구성된다. 모의실험 결과, 제안된 ATR 기법은 톤 예약이 가능한 최적의 톤을 클리핑 잡음을 이용하여 추출함으로써 기존 TR 방법의 계산량을 획기적으로 줄이면서도 성능이 최적의 TR 방법에 근접한 것을 보여준다.

• 대한치과마취과학회지
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• 제12권4호
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• pp.235-241
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• 2012

Although sevoflurane sedation have the advantage of the reduction of anxiety and pain relief, difficult airway is attributed to increased agitation, tachycardia, desaturation, ventilation difficulty, sedation failure. In the sedation for dental treatment, we should pay more attention to the airway management because dental procedures take place in the mouth of airway unlike any other area. The layngeal mask airway (LMA) has become commonly used device for airway management during anesthesia for relatively short procedures, such as minor oral surgery and dental procedures. It can be inserted without use of a larygoscope and muscle relexants, and insertion is easy to achieve and generally takes less time than endotracheal intubation. The LMA is an excellent barrier against aspiration of saliva, blood within the surgical field but should not be used in patients at risk of aspiration In this study, we reported that after a failure of airway management in inhalation sedation, we performed the short-emergency dental treatment successfully, using a laryngeal mask.

• 대한치과의사협회지
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• 제49권11호
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• pp.670-678
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• 2011

Various sorts of dental devices for the dental treatment have been introduced and adopted during past several years. Dental Laser, among all devices, seems to be possible for applying to over the whole treatments and widely employed. Furthermore, this article is to introduce that Dental Laser is intended to care patients secured with the effectual treatment against Conventional procedures based upon its studies. The advantages of Dental Laser treatment-along with LLLT (Low Level Laser Therapy) effect, biostimulation effect, and minimal invasive technique - make the patients reduce their fear of the operation, lighten the inconvenience of post operation, and shorten the treatment period. In particular, it is worth considering that the use of laser-assisted therapies is associated with a marked reduction in the use of analgesics and anti-inflammatory medications compared with conventional procedures. This article is to state advantages and differences of Dental Laser treatment compared with Conventional procedures, and to emphasize to become well-acquainted with the precautions for safety and effective Dental Laser treatment. In case of operating Dental Laser with lack of the instructions, it will cause the unpredicted fatal results; therefore this treatment requires special care in its operation. Henceforward, it is anticipated that infinite treatment protocols will be introduced by applying Dental Laser, and this is to address the utilization of Dental Laser.

• Journal of Korean Neurosurgical Society
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• 제47권6호
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• pp.433-436
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• 2010

Objective : Arachnoid cysts (ACs) can be cured by making the definite and wide communication between the cyst and arachnoid space using endoscopy, but often it is impossible only through the usual working-channel (intra-channel) procedures. We discuss and propose a more valuable endoscopic technique with the presentation of our series of cases. Methods : We treated 9 patients with cortical AC in various locations with extra-channel endoscopic techniques. The patients ranged in age from 3 years to 60 years (mean age, 37.2 yrs). The follow-up period ranged from 12 to 26 months (mean follow-up duration, 17.2 months). All patients had large AC compressing the adjacent brain with clinical symptoms or signs. The authors performed extensive fenestration via single burr hole with the aid of endoscope. Being bypassed the rigid endoscope, through the space between the shaft of endoscope and guiding cannula (extra-channel method), fenestration procedures were done in the dry fields. Results : Eight (88.9%) patients had been treated successfully with endoscope. One patient required shunt procedure. Among the eight patients who were treated with endoscopic procedure, 6 patients (66.7%) showed cyst reduction, and two (22.2%) showed disappearance of cyst. Conclusion : We suggest that extra-channel method will be simple and easy to perform using more valuable instruments with wider working area, and may promise better results compared to the conventional intra-channel endoscopic procedures.

• 한국분말재료학회지
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• 제10권5호
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• pp.337-343
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• 2003

Nanostructured Cu-$Al_2O_3$ composite powders were synthesized by thermochemical process. The synthesis procedures are 1) preparation of precursor powder by spray drying of solution made from water-soluble copper and aluminum nitrates, 2) air heat treatments to evaporate volatile components in the precursor powder and synthesis of nano-structured CuO + $Al_2O_3$, and 3) CuO reduction by hydrogen into pure Cu. The suggested procedures stimulated the formation of the gamma-$Al_2O_3$, and different alumina formation behaviors appeared with various heat treating temperatures. The mean particle size of the final Cu/$Al_2O_3$ composite powders produced was 20 nm, and the electrical conductivity and hardness in the hot-extruded bulk were competitive with Cu/$Al_2O_3$ composite by the conventional internal oxidation process.