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.

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.

수종의 조직 양화재에서 탄성 변형과 복원에 관한 연구

최성호,심준성,문홍석,정문규,Choi Sung-Ho,Shim June-Sung,Moon Hong-Seok,Chung Moon-Kyu 대한치과보철학회 2003 대한치과보철학회지 Vol.41 No.1

The dimensional stability of tissue conditioners characterizes the ability of the materials to yield accurate functional impressions of oral mucosa. This study evaluated the viscoelastic property and the linear dimensional changes with the factor of time and thickness of tissue conditioners ($COE-COMFORT^{TM}$, Visco-gel. $COE-SOFT^{TM}$, Soft-Liner). The thickness of these materials were changed (1.5mm, 3.0mm) and the percentage changes in dimension were measured at 1h, 12h, 24h, 36h, 3day, 7day after specimen preparation. From the results large differences appear between the various tissue conditioners. The results suggest that the period recommended for forming functional impression would be 2-3days after insertion in the mouth. in addition. it is important to select tissue conditioners suitable for functional impression because of the wide range of dimensional stability among the materials.

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.

성견 1면 치조골 결손부에서 $Emdogain^{(R)}$과 $Emdogain^{(R)}$ 및 특수 제조된 Calcium Sulfate Paste 혼합물이 치주조직 치유에 미치는 영향

최성호,김창성,서종진,김현영,김정혜,조규성,김종관,Choi, Seong-Ho,Kim, Chang-Sung,Suh, Jong-Jin,Kim, Hyun-Young,Kim, Jeong-Hye,Cho, Kyoo-Sung,Kim, Chong-Kwan 대한치주과학회 2000 Journal of Periodontal & Implant Science Vol.30 No.3

Recently, it was reported that enamel matrix derivative may be beneficial in periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The aim of present study was to evaluate the effect of enamel matrix derivative($Emdogain^?$)and Caso4 sulfate paste in 1-wall intrabony defects in beagle dogs. Surgically created 1-wall intrabony defects were randomly assigned to receive root debridement alone or $Emdogain^{(R)}$ or $Emdogain^{(R)}$ and Caso4. Clinical defect size was 4 X 4mm. The control group was treated with root debridement alone,and Experimental group I was treated with enamel matrix derivative application, and Experimental group II was treated with enamel matrix derivative and Caso4 sulfate paste application,. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows: 1. The length of junctional epithelium was $0.41{\pm}0.01mm$ in the control group, $0.42{\pm}0.08mm$in the experimental group I and $0.50{\pm}0.13mm$in the experimental group II. 2. The connective tissue adhesion was $0.28{\pm}0.02mm$ in the control group, $0.13{\pm}0.08mm$ in the experimental group I and $0.19{\pm}0.02mm$ in the experimental group II. 3. The new cementum formation was $3.80{\pm}0.06mm$ in the control group, $4.12{\pm}0.43mm$ in the experimental group I and $4.34{\pm}0.71mm$ in the experimental group II. 4. The new bone formation was $1.43{\pm}0.03mm$ in the control group, $1.53{\pm}0.47mm$ in the experimental group I and $2.25{\pm}1.35mm$ in the experimental group II. Although there was limitation to present study, the use of enamel matrix derivative in the treatment of periodontal 1-wall intrabony defect enhanced new cementum and bone formation. Caso4 sulfate paste will be the candidate for carriers to deliver enamel matrix derivative, and so enhance the regenerative potency of enamel matrix derivative.

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.

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.

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.

성과 피드백, 정당성, 그리고 준거집단 성과가 리포지셔닝에 미치는 영향 - 북미 원유 및 천연가스 산업 분석을 중심으로 -

최성호,Choi, Sung-Ho 대한경영정보학회 2017 경영과 정보연구 Vol.36 No.3

This study investigates the determinants of strategic positional change. Specifically, the study suggests performance feedback affects to a firm's strategic repositioning. Performance feedback is a concept that a firm decides whether success or not by comparing its performance relative to its aspiration level. Prior studies successively discover diverse behaviors. The study suggests three unexplored relationships between performance gaps and strategic positioning. First, when a firm's performance is below relative to its aspiration level, that firm's strategic position will be deviate from the industry norm. Second, as the degree of industrial density increases, the tendency that a firm's strategic position becomes deviate from the industry norm decreases. Third, when the degree of reference group's performance decreases, the tendency that a firm's strategic position becomes deviate from the industry norm decreases. For empirical analysis, this study examines data of 538 firms that in North America crude petroleum and natural gas industry. The result reveals that the direction of a firm's strategic change is shaped when firms' performance is below relative to aspiration level. Also, this relationship is moderated as industrial density changes or when reference groups' performance decreases. This study contributes to the current literature by explaining how a firms' strategic position is decided. Also, this study reveals that reference groups' performance could affect to organizational choice.

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.