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.

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.

위성 보험

최성호,Choi, Seong-Ho 한국위성정보통신학회 2008 위성통신과 우주산업 Vol.15 No.1

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.

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.

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.

Dura meter가 성겹 3급 분지부 병소에 미치는 영향

최성호,김준일,문익상,조규성,채중규,김종관,Choi, Sung-Ho,Kim, Joon-Il,Moon, Ik-Sang,Cho, Kyoo-Sung,Chai, Jung-Kyu,Kim, Chong-Kwan 대한치주과학회 1996 Journal of Periodontal & Implant Science Vol.26 No.3

The present study evaluates the effects of dura mater barrier membranes In class III furcation defects on the regeneration of periodontal tissues in dogs. Experimental class III furcation defects were created surgically by removing alveolar bone horizontally down to 4mm from CEJ in mandibular premolars of adult dogs. Dura mater barrier membranes were applied bucco-lingually in the test group, and flap surgery only with no membranes in the control group. The healing was evaluated clinically and histologically after 8weeks. Clinically, the test group showed slight exposures of the membranes, while the control group showed no furcation exposure, The test specimens showed new bone formation coronal to the notch, while the control specimens had new bone formation up to the level of the notch. New cementum was observed in both groups. The test specimens showed functional arrangements of connective tissue fibers between new bone and new cenentum, while irregular arrangements were observed in the controls. No root resorption or ankylosis were observed in either groups,These results suggest that dura mater resorbable barrier membranes on class III furcation defects may be effective in regeneration of alveolar bone and peridontal ligament.

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.

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.