영아기에 시행한 단일 또는 임시 이중인공수정체삽입술 후 굴절력 변화 및 합병증 비교 연구

최성호,정태영,정의상,Sung-Ho Choi,Tae-Young Chung,Eui-Sang Chung 대한안과학회 2005 대한안과학회지 Vol.46 No.4

Purpose: The purpose of this study was to assess the incidence of postoperative complications and the change of refractive error in infantile eyes after cataract surgery and single intraocular lens(IOL) or temporary piggyback IOL implantation. Methods: Eight consecutive patients (13 eyes) who underwent IOL implantation under 12 months of age between 1999 and 2002 were enrolled. Eight eyes of 6 patients had a single IOL implanted and the other 5 eyes of 3 patients underwent temporary piggyback IOL implantations. A retrospective chart review was conducted. Results: The mean age at surgery was 6.1 months. The mean follow-up period was 10 months. The average postoperative refraction at one week was +7.82D after single IOL and +0.32D after piggyback IOL. The average postoperative refraction at last follow-up was +4.25D and -3.5D respectively. Over the follow-up period, the mean refractive change per months was -0.34D in the single IOL group and -0.45D in the piggyback IOL group. Postoperative complications were 12.5 % (1/8 eyes) in single IOL and 20.0% (1/5 eyes) in piggyback IOL. Reoperations were conducted for the complicated eyes in both groups. Conclusions: The rates of complications and reoperations were slightly higher in piggyback IOL than in single IOL. Nonetheless, additive correction for residual hyperopia was not needed in the piggyback IOL group. There was more deteriorative evidence of amblyopia in piggyback IOL than in single IOL.

RF 전자기장 생체 영향 연구 문헌에서 노출량 메타분석을 위한 통계적 기법

최성호,김남,Choi, Sung-Ho,Kim, Nam 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.12

본 논문에서는 RF 전자기장을 사용한 동물 및 세포 실험에서 전자기장 노출량의 정확성을 평가할 수 있는 방법을 제안하였다. 이를 위해 전자파 흡수율(SAR)을 전자기장 노출량의 단위로 사용한 동물 및 세포 연구 논문과 휴대폰 및 PDA에 대한 전자파 흡수율 시험 성적서를 대상으로 출력 전력, 전력 밀도 등과 SAR의 상관 관계 및 회귀 관계를 분석하였다. 동물 실험의 경우 전력 밀도와 SAR이, 세포 실험의 경우 출력 전력이 duty factor를 고려한 SAR과 통계적으로 유의한 상관 관계를 보였다. 회귀분석에서의 노출 불확실성을 평가하기 위해 결정계수값을 분석하였다. 각각의 실험장치 및 방법에 대한 해석 또는 측정 기법의 분석 이전에 본 연구 방법을 실시하여 대상 연구군의 특성을 고찰한다면 보다 효율적인 전자기장노출신뢰성 평가를 실시할 수 있을 것으로 판단된다. This paper proposed the estimating method of electromagnetic dosimetric reliability at in-vivo and in-vitro experiments. For more accurate consequences of these researches, we have tried to find out any correlations among output power, power density and specific absorption rate(SAR) with the results of in-vivo, in-vitro tests and SAR reports of cellular phone and PDA. In the case of in-vivo tests, the power density has close statistical correlations with SAR value and in the event of in-vitro tests, the output power has considerable statistical correlations with SAR containing duty factor. We analysed the coefficient of determination to estimate the dosimeoic uncertainty. If we use this method before evaluating techniques of measurement and analysis at both in-vivo and in-vitro experiments, we will conduct more accurate reliability test.

성인성 치주질환에서 미노클린 국소송달제 효과에 대한 연구

최성호,현석주,구현서,서종진,조규성,채중규,김종관,Choi, Seong-Ho,Hyun, Suk-Ju,Koo, Hyun-Seo,Suh, Jong-Jin,Cho, Kyoo-Sung,Chai, Jung-Kui,Kim, Chong-Kwan 대한치주과학회 1998 Journal of Periodontal & Implant Science Vol.28 No.2

20 Subjects with clinical diagnosis of adult periodontitis with sites having average pocket depth of 4mm were selected for the study. After scaling and root planing of those sites, 30% minocycline-HCI contained in biodegradable device were inserted in one group, scaling and root planing was carried out in another group and the last group was without any periodontal treatment. the difference between the group was detemined by pocket dept, bleeding on prbing, attachment level, distribution of subgingval plaque bacteria. Conclusion was made for the comparisons between baseline and 4 week and the groups. 1. In analysis of pocket depth, there was significant sifference in scaling and root planing group only. 2. Both the scaling and root planing group and minocycline group showed significant decrease in bleeding on probing. 3. There was significant increase in the attachment level in scaling and root planing group, but no difference was foundbetween the groups. 4. There was significant decrease in the total number of subgingival bacteria in all groups and the number of motile bacteria decreased significantly in the minocycline group. These result indicate that insertion of Minocycline-HCI at the base of periodntal pocket was useful as an additional aid of mechanical trarment at the point of periodontal pocket, bleeding on probing, attachment level, microbial distribution.

디지털 데이터 가치의 정량적 측정에 대한 개념적 연구

최성호,이상곤,Choi, Sung Ho,Lee, Sang Kon 한국IT서비스학회 2022 한국IT서비스학회지 Vol.21 No.5

With the rapid development of computer technology and communication networks in modern society, human economic activities in the almost every field of our society depend on various electronic devices. The huge amount of digital data generated in these circumstances is refined by technologies such as artificial intelligence and big data, and its value has become larger and larger. However, until now, it is the reality that the digital data has not been clearly defined as an economic asset, and the institutional criteria for expressing its value are unclear. Therefore, this study organizes the definition and characteristics of digital data, and examines the matters to be considered when considering digital data in terms of accounting assets. In addition, a method that can objectively measure the value of digital data was presented as a quantitative calculation model considering the time value of profits and costs.

성견 열개형 결손부에 DFDB이식과 Dura Mater막의 효과

최성호,김일영,김영희,서종진,정현철,조규성,채중규,Choi, Seong-Ho,Kim, Il-Young,Kim, Young-Hee,Suh, Jong-Jin,Jung, Hyun-Chul,Cho, Kyoo-Sung,Chai, Jung-Kiu 대한치주과학회 1998 Journal of Periodontal & Implant Science Vol.28 No.2

The present study invetigates the effects of root planing only(control group), DFDBA alone(test group 1) and combined use of DFDB and Dura mater(test group 2) in dehiscence defects in dogs. The results of 8weeks post-surgery by histological comparison between the three groups are as follows. 1. The contol group showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 2. The test group 1 showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 3. The test group 2 showed significant amount of the new cementum and new bone. 4. Both control and test groups healed without any observable root resorption and ankylosis. The above the results suggest that the use of resorbable Dura mater only does not improve the regeneration of new bone and periodontal ligament due to difficulties of space making, but the combined use with DFDB may be more effective.

가변 스펙트럼 할당을 지원하는 광대역 전력 증폭기를 위한 디지털 전치왜곡기

최성호,서성원,마백일,정의림,Choi, Sung-Ho,Seo, Sung-Won,Mah, Bak-Il,Jeong, Eui-Rim 한국정보통신학회 2011 한국정보통신학회논문지 Vol.15 No.2

인지통신(cognitive radio)과 같이 가변 스펙트럼 할당이 필요한 시스템을 위한 새로운 전치왜곡기를 제안한다. 본 논문에서 고려하는 시스템 모델에서 신호는 한 순간에는 작은 대역폭을 차지하지만 그 중심 주파수가 시간에 따라 변화할 수 있는 상황을 가정한다. 이러한 시나리오에서는 전력 증폭기 출력 단에 위치하는 종단 필터로는 전력증폭기에 의한 하모닉을 제거하지 못하는 상황이 발생할 수 있다. 제안된 전치왜곡기는 기본 주파수 (${\omega}_0$) 신호의 비선형 왜곡을 선형화할 뿐만 아니라, $2{\omega}_0$, $3{\omega}_0$, ...에서 발생하는 하모닉도 동시에 제거한다. 제안된 전치왜곡기는 ${\omega}_0$ 주파수의 정수배에 대응하는 여러 개의 전치왜곡기가 결합된 구조를 가지고 있다. 기본 주파수 ${\omega}_0$에 해당하는 전치왜곡기는 기본 주파수 신호의 선형화를 담당하며, 나머지 주파수에 대응하는 전치왜곡기는 하모닉을 제거하는 역할을 담당한다. 제안된 전치왜곡기에서 필요한 변수는 최소 평균 자승 에러 알고리즘에 의해 동시에 계산되며, 모의실험 결과에 따르면 제안된 방법을 이용하면 기본 주파수의 스펙트럼에 발생하는 스펙트럼 왜곡이 20dB 감소하며, 2차 및 3차 하모닉도 기본 신호의 전력대비 약 -70dB로 작아지는 것을 확인할 수 있다. A new predistortion technique for dynamic spectrum allocation systems such as cognitive radio (CR) is proposed. The system model considered in this paper occupies a small band at a time, but the center frequency can be changed in the wide range of frequency. In this scenario. the front-end filter may not eliminate the harmonics of the power amplifier (PA) output. The proposed PD reduces the spectral regrowth of the fundamental signal at the carrier frequency (${\omega}_0$) and removes the harmonics ($2{\omega}_0$, $3{\omega}_0$, ...) at the same time. The proposed PD structure is composed of multiple predistorters (PDs) centered at integer multiples of ${\omega}_0$. The PD at ${\omega}_0$ is for removing spectral regrowth of the fundamental signal, and the others are for harmonic reduction. In the proposed PD structure, parameters of PDs are found jointly. Simulation results show that the spectral regrowth can be reduced by 20dB, and the 2nd and 3rd harmonics can be reduced down to -70dB from the power of the fundamental signal.

다중 대역 전송 시스템을 위한 전치왜곡 알고리즘

최성호,이병환,이철수,정의림,Choi, Sung-Ho,Lee, Byung-Hwan,Lee, Chul-Soo,Jeong, Eui-Rim 한국정보통신학회 2012 한국정보통신학회논문지 Vol.16 No.1

본 논문에서는 다중 대역 전송 시스템에서 광대역 전력 증폭기의 선형화를 위한 새로운 전치왜곡 기법을 제안한다. 특히, 한 시스템에서 동시에 다중대역/다중모드 신호를 전송함에 있어 다중대역 신호가 하나의 전력 증폭기에 의해 증폭되어 전송되는 시스템을 고려한다. 상호 대역 간 비선형 왜곡을 포함한 비선형 특성을 보상하기 위하여, 본 논문에서는 다중 전치왜곡기 블록을 갖는 새로운 전치왜곡 구조를 제안하며, 다중 전치왜곡기의 계수를 동시에 갱신하는 적응 알고리즘을 제안한다. 제안하는 다중 대역 모델을 검증하기 위하여 상용 증폭기를 사용하여 증폭기 모델을 추출하였으며, 추출된 모델을 기반으로 제안한 알고리즘을 모의실험을 통해 검증하였다. 모의실험 결과는 제안 알고리즘이 효과적으로 다중 전치왜곡기의 계수를 구할 수 있으며, 다중 대역을 효과적으로 선형화 할 수 있음을 보여준다. New digital predistortion technique is proposed for power amplifier linearization in multi-band transmission systems. We consider a system where muli-band signals are combined and amplified by a single power amplifier (PA). In this system, the PA output is distorted by the nonlinear cross-products between different band signals as well as their own nonlinear self-products. To compensate these nonlinear effects, we propose a multiple PD structure. Each PD removes the nonlinear cross-products and self-products to mitigate the spectral regrowth for the corresponding band. Since the PD parameters for different bands are linked together, it is difficult to find the PD parameters separately. Thus, we propose an iterative method for finding the PD parameters jointly. For demonstration of the proposed method, multi-band characteristics of PA are extracted from a commercial power amplifier. Computer simulation was executed based on the PA parameters. The simulation results show that the proposed method can effectively linearize the PA and remove spectral regrowth at each signal band.

반복적인 펄스레이저 조사에 의한 알루미늄 합금의 표면상태 변화분석

최성호,김정석,장경영,신완순,Choi, Sung-Ho,Kim, Chung-Seok,Jhang, Kyung-Young,Shin, Wan-Soon 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.5

The objective of this study is to investigate the thermal behavior on material surface and the variation in the surface morphology of aluminum 6061 alloy by the Nd:YAG pulsed-laser irradiation. First, we predicted the surface temperature variation during pulsed-laser irradiation by using the two dimensional finite element analysis. When the pulsed-laser of 133 mJ energy and 5 ns pulse duration is irradiated on the surface of aluminum alloy, the material surface is thought to be melting because the surface temperature rises steadily up to about $660^{\circ}C$ exceeding the melting point. Also, the experimental results show that the solidification microstructure has been developed clearly after surface melting. Second, the diameter of melted zone was analysed by finite element analysis and measured by OM(Optical Microscopy). It increased logarithmically with increase in the number of laser irradiation. In addition, AFM(Atomic Force Microscopy) measurement showed an increase in the average surface roughness during pulsed-laser irradiation.

성견 열개형 수평 결손부에서 Calcium Sulfate 차단막이 치주조직 치유에 미치는 영향

최성호,조규성,문익상,채중규,김종관,Choi, Seong-Ho,Cho, Kyu-Sung,Moon, Ik-Sang,Chai, Jung-Kyu,Kim, Jong-Kwan 대한치주과학회 1997 Journal of Periodontal & Implant Science Vol.27 No.1

The present study investigates the effects of calcium sulfate graft on the periodontal healing in intrabony periodontal defects of dogs. Following the general anesthesia with 30mg/kg pentobarbital injected intravenously, the first premolar was extracted and full-thickness periodontal flap was elevated from the second premolar to the fourth premolar. The portion of premolars coronal to the alveolar crest was removed and mesial and distal roots were separated. Exposed root canals were sealed with Caviton and covered completely with flaps sutured. Following the healing period of 12 weeks, the surgical sited were uncovered and $4{\times}4mm$ intrabony defects were surgically created. Those defects with calcium sulfate graft following the root planing was designated as the test sites and those with flap surgery-only were designated as control sites. The animals were sacrificed after 8 weeks and the healing was histologically analyzed. The results were as follows. 1. No foreign body reaction or inflammation were observed in either groups. Calcium sulfate was completely resorbed in the test sites. 2. New cementum was observed coronal to the notch in both groups. Connective tissue fibers were oriented parallel to the root surface in the controls. Connective tissues were formed in large amount in the sites. 3. Test sites showed marked amount of new bone formation while the control sites showed minimal bone gain. 4. Root resorption was observed in coronal portions of th control Sites. The results suggest that calcium sulfate is a biocompatible graft material with a potential for new bone and cementum formation.

소방항공대의 최적 운영을 위한 개선방안 연구

최성호,최연철,지용선,이영종,김동용,Choi, Sung-Ho,Choi, Yeon-Chul,Ji, Yong-Sun,Lee, Young-Jong,Kim, Dong-Yong 한국항공운항학회 2015 한국항공운항학회지 Vol.23 No.1

Recently, even though firefighting operations are supposed to be incorporated into single body IAW restructuring of the government organizations, in terms of efficiency it is still difficult to find any significant improvements due to the centrally and locally segregated operating bodies and also, as with organizations firefighting manpowers are divided nationally and locally, which results in differing firefighting functioning. Although governments firefighting bodies are changed to operate better, there are always limitations in firefighting operations. This study explores firefighting organizations, manpower, equipment and operations itself to optimize firefighting operations, and ultimately, to provide the future-oriented functions and roles of the firefighting aviation corps.