• KSBB Journal
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• 제24권3호
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• pp.279-286
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• 2009

방선균은 다양한 생리활성 물질을 이차대사산물로 생산하는 산업적으로 매우 유용한 미생물이다. 이에 따라 많은 연구진들이 방선균에 대한 분자생물학적 연구와 산업적 이용에 대한 연구들을 수행하고 있다. 방선균 중에서도 S. avermitilis는 강력한 구충효과가 있는 avermectin을 생산하지만, 또한 포유동물 세포의 미토콘드리아에서 산화적 인산화반응을 억제하는 oligomycin도 함께 생성된다. 따라서 S. avermitilis에서 oligomycin의 생성을 제거시키기 위하여 oligomycin synthetase gene을 disruption 시키기 위한 연구를 수행하였다. 이를 위하여 S. avermitilis로부터 cloning 한 oligomycin synthetase gene (olmA5)의 중앙부분에 apramycin resistance gene을 끼워 넣어 integration vector로 구축한 후에 S. avermitilis의 chromosomal DNA와의 homologous recombination에 의하여 olmA5 gene의 disruption을 유도하였다. Disruption mutants (olmA5::apra)는 PCR을 통해 olmA5 gene의 위치에 apramycin resistance gene이 존재하는 것으로 확인하였고, 또한 HPLC 분석을 통해 oligomycin 생합성이 완전히 제거된 것임을 확인하였다. 그러나 disruption mutant (olmA5::apra)를 이용하여 avermectin 만을 생산할 수 있었으나, avermectin의 생산량에는 거의 변화가 없었다. 이러한 mutants는 산업적으로 avermectin을 생산하기 위한 균주 개량의 훌륭한 source가 될 수 있을 것이다.

• Journal of Korean Neurosurgical Society
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• 제46권6호
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• pp.515-521
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• 2009

Objective : The purpose of this study was to compare clinical and radiological outcomes of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM) for recurrent disc herniation. Methods : Fifty-four patients, who underwent surgery, either PELD (25 patients) or repeated OLM (29 patients), due to recurrent disc herniation at L4-5 level, were divided into two groups according to the surgical methods. Excluded were patients with sequestrated disc, calcified disc, severe neurological deficit, or instability. Clinical outcomes were assessed using Visual Analogue Scale (VAS) score and Oswestry Disability Index (ODI). Radiological variables were assessed using plain radiography and/or magnetic resonance imaging. Results : Mean operating time and hospital stay were significantly shorter in PELD group (45.8 minutes and 0.9 day, respectively) than OLM group (73.8 minutes and 3.8 days, respectively) (p < 0.001). Complications occurred in 4% in PELD group and 10.3% in OLM group in the perioperative period. At a mean follow-up duration of 34.2 months, the mean improvements of back pain, leg pain, and functional improvement were 4.0, 5.5, and 40.9% for PELD group and 2.3, 5.1, and 45.0% for OLM group, respectively. Second recurrence occurred in 4% after PELD and 10.3% after OLM. Disc height did not change after PELD, but significantly decreased after OLM (p = 0.0001). Neither sagittal rotation angle nor volume of multifidus muscle changed significantly in both groups. Conclusion : Both PELD and repeated OLM showed favorable outcomes for recurrent disc herniation, but PELD had advantages in terms of shorter operating time, hospital stay, and disc height preservation.

• 에너지공학
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• 제29권1호
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• pp.52-57
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• 2020

가동중정비(OLM : On-Line Maintenance)란 발전소 건전성 유지를 위해 운전 중에 수행하는 예방정비 활동으로 특히 안전설비에 대해 운전 중에 수행하는 예방정비 활동을 말한다. 국내 원자력발전소에서는 2009년부터 가동중정비 도입을 위한 타당성검토를 수행하였고 2010년 규제기관에서도 규제지침에 대한 연구과제를 완료하여 가동중정비 도입을 검토하였으나 후쿠시마 사고 등 원자력발전소의 대외여건 변화 등으로 도입검토가 중단된 상태이다. 하지만 원전의 안전성과 운전성을 향상시키기 위하여 근본적인 대책 수립이 요구되고 있는데 이를 위하여 필요한 가동중정비가 왜 필요한지 어떠한 효과가 있는지 등에 대하여 고찰하여 보았다.

• 한국압력기기공학회 논문집
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• 제8권2호
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• pp.21-25
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• 2012

Functional Equipment Group(FEG) of Nuclear Power Plant(NPP) is the bundling of multiple equipment subcomponents around a major equipment with a common system isolation characteristic or out-of-service consideration. The main purpose of FEG is to reduce out-of-service time to enhance maintenance effectiveness. KHNP(Korea hydro & Nuclear Power Co.) needs to develop these FEGs to successfully perform On-line Maintenance(OLM) which will be expected to institute in the future. Recently, there has been growing interest in OLM in KHNP. The aim of this paper is to suggest the way of FEG development and to build the FEG of MCR(Main Control Room) HVAC(Heat, Ventilation and Air Conditioning) system. The results of this study might be make good use of OLM and be helpful for equipment maintenance for MCR HVAC system.

• Journal of Korean Neurosurgical Society
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• 제44권5호
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• pp.320-326
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• 2008

Objective : To evaluate the risk factors that may be responsible for the development of contralateral reherniations from ipsilateral ones after open lumbar microdiscectomy (OLM), and to compare surgical outcomes of revision OLM for contralateral reherniations with those for ipsilateral ones. Methods: Seventeen patients who underwent revision OLM for contralateral reherniation were enrolled into Group I, and 35 patients who underwent revision OLM for ipsilateral reherniation were enrolled into Group II. Using medical charts and imaging study results, the differences in the clinical and radiological factors were evaluated between the two groups. Clinical outcomes of each group were compared between the two groups. Results: Significant differences were found in the interval to reherniation from initial surgery (33 months for Group I and 18.6 months for Group II, p=0.009), as well as in the incidences of both protruded disc (35.3% for Group I and 8.6% for Group II, p=0.045) and mild disc degeneration (29.4% for Group I and 5.7% for Group II, p=0.031) at initial surgery. On binary multi-logistic regression analysis, significant differences were found in the interval to reherniation (p=0.027, Odds ratio=1.051) and incidence of mild disc degeneration (p=0.025, Odds ratio= 12.03) between the two groups. There were no significant differences in the improvement of clinical outcomes after revision OLM between the two groups. Conclusion: The interval to reherniation from initial surgery and the grade of disc degeneration at initial surgery were key factors that distinguished the development of contralateral reherniations from ipsilateral ones. Surgical outcomes of revision OLM were similar in both groups.

• 대한물리치료과학회지
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• 제7권1호
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• pp.353-365
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• 2000

The purpose of this study were to compare the lumbar extensor strength between pre op patients group and after 6 weeks post op patients group. To evaluate lumbar extensor strength of total 273 patients with HIVD. Lumbar extensor strength was measured in 151 male patients and 122 female patients(Lumbar extensor strength was measured in 91 PELD patients group and 182 OLM group patients) by Medx lumbar extension machine. Maximum voluntary lumbar extension strength was appear $149.36{\pm}61.92ft$-lbs in pre op of PELD group, $158.47{\pm}54.67ft$-lbs in post op of PELD group and $135.54{\pm}54.24ft$-lbs in pre op of OLM group. $147.19{\pm}52.42ft$-lbs in post op of OLM group in male. Maximum voluntary lumbar extension strength was appear $83.85{\pm}30.22ft$-lbs in pre op of PELD group. $92.99{\pm}28.66ft$-lbs in post op of PELD group and $75.16{\pm}24.98ft$-lbs in pre op of OLM group, $79.88{\pm}25.25ft$-lbs in post op of OLM group in female. Male and female lumbar extension strength was statistically significant difference(P<.05). Lumbar flexion/extension ratio of the two group was 2.14:1 pre op and 2.05:1 post op in lumbar flexion 72 and 0 degree. The ratio of post op group was lesser than pre op group.

• PNF and Movement
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• 제10권2호
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• pp.25-31
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• 2012

Purpose : The purpose of this study is to figure out the effects of Open Laser Microdiscectomy(OLM) on deep muscles by comparing multifidus and longissimus muscle size (cross section area; CSA) of pre and post operation. Methods : The subjects consisted of forty patients who had OLM. The data were analyzed with paired t-test comparing left and right deep muscle CSA of pre and post-operation, and both the deep muscle CSA of pre and post-operation, using SPSS ver. 15.0 program. Results : The results of this study showed a significant difference in deep muscle size (CSA) between pre and post operation (p<.05). Although there was not a meaningful difference between right and left deep muscle size (CSA) in pre operation (p>.05), there was a significant difference between both of them in post operation (p<.05). Conclusion : Therefore we made the conclusion that the operation causes decrease of muscle tone in deep muscles and muscle imbalance by causing muscle atrophy in the lumbar deep muscle after the operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.588-590
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• 2006

Recently, many on-line approaches to instrument channel surveillance (drift monitoring and fault detection) have been reported worldwide. On-line monitoring (OLM) method evaluates instrument channel performance by assessing its consistency with other plant indications through parametric or non-parametric models. The heart of an OLM system is the model giving an estimate of the true process parameter value against individual measurements. This model gives process parameter estimate calculated as a function of other plant measurements which can be used to identify small sensor drifts that would require the sensor to be manually calibrated or replaced. This paper describes an improvement of auto-associative kernel regression by introducing a correlation coefficient weighting on kernel distances. The prediction performance of the developed method is compared with conventional auto-associative kernel regression.

• International Journal of Contents
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• 제12권4호
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• pp.31-44
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• 2016

Knowledge creation and management are regarded as critical success factors for an organization's survival in the knowledge era. As a process of knowledge acquisition and sharing, organizational learning mechanisms (OLMs) guide the learning function of organizations represented by its different learning activities. We examined a variety of learning processes that constitute OLMs. In this study, we aimed to capture the process and framework of OLMs and knowledge sharing and acquisition. Factors facilitating OLMs were investigated at three levels: individual, group, and organizational. The concept of an OLM has received some attention in the field of organizational learning, however, the relationship among the factors generating OLMs has not been empirically tested. As part of the ongoing discussion, we attempted a systemic approach for OLMs. OLMs can be represented by factors that are inherent to the organization's system; therefore, prior to empirically testing the OLM generating factor(s), evaluation of its organizational integration is required to determine effective treatment of each factor. Thus, we developed a framework to manage knowledge and proposed a method to numerically evaluate factors influencing the OLMs. Specifically, composite importance (CI) of the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method was applied to explore the interaction effect of these factors based on systemic approach. The augmented matrix thus generated is expected to serve as a stochastic matrix of an absorbing Markov chain.

• 한국레이저가공학회지
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• 제4권1호
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• pp.39-48
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• 2001

This study was performed to evaluate basic characteristics of electron beam weldability for high strength aluminum alloys. The aluminum alloys used were A5083 and A6N01, and A7N01. The principal welding process parameters, such as accelerating voltage, beam current, welding speed and chamber pressure were investigated. The dimension and microstructure of welds were evaluated with OLM, and SEM (EDAX). In addition, weldability variation(cracking) due to process parameters was also evaluated. The degree of cracking in the EB fusion zone appears to be affected mainly by aspect ratio, such that as aspect ratio increases the cracking tendency also increases. The alloying element itself may also affect the hot cracking resistance, but its role is considered to be indirect effect such that the relatively higher vaporization pressure elements of Zn and Mg give deeper weld penetration and thus results in greater cracking tendency.