• 한국정밀공학회지
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• 제18권7호
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• pp.46-52
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• 2001

This study describes the precision control of the torque standard machine using a self-tuning fuzzy controller. The torque standard machine should generate the accurate torque for calibrating a torque sensor. In order to reduce the relative expanded uncertainty of the torque standard machine, when a weight is hanged to the end of the torque arm for generating the torque, the sloped torque arm should be accurately controlled to the horizontal level. If the slope of the torque arm is larger from the inaccurate control, the uncertainty of the torque standard machine due to control will be larger. This applies the inaccurate torque to a torque sensor to calibrate, and the measuring error of the torque sensor generate from it. Therefore the torque arm of the torque standard machine is accurately controlled. In this paper, the self-tuning fuzzy controller was designed using a fuzzy theory, and the torque arm of the torque standard machine was accurately controlled. The control gain of the fuzzy controller, that is the membership function size of the error, the membership function size of the error change and the membership function size of the controller were determined from the self-tuning. The control results of the torque standard machine were the overshoot within 0.0076mm, the rise time within 16.70sec and the steady state error within 0.0076mm.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.959-982
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• 2015

In this study, a non-stationary random earthquake Clough-Penzien model is used to describe earthquake ground motion. Using stochastic direct integration in combination with an equivalent linear method, a solution is established to describe the non-stationary response of lead-rubber bearing (LRB) system to a stochastic earthquake. Two parameters are used to develop an optimization method for bearing design: the post-yielding stiffness and the normalized yield strength of the isolation bearing. Using the minimization of the maximum energy response level of the upper structure subjected to an earthquake as an objective function, and with the constraints that the bearing failure probability is no more than 5% and the second shape factor of the bearing is less than 5, a calculation method for the two optimal design parameters is presented. In this optimization process, the radial basis function (RBF) response surface was applied, instead of the implicit objective function and constraints, and a sequential quadratic programming (SQP) algorithm was used to solve the optimization problems. By considering the uncertainties of the structural parameters and seismic ground motion input parameters for the optimization of the bearing design, convex set models (such as the interval model and ellipsoidal model) are used to describe the uncertainty parameters. Subsequently, the optimal bearing design parameters were expanded at their median values into first-order Taylor series expansions, and then, the Lagrange multipliers method was used to determine the upper and lower boundaries of the parameters. Moreover, using a calculation example, the impacts of site soil parameters, such as input peak ground acceleration, bearing diameter and rubber shore hardness on the optimization parameters, are investigated.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권2호
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• pp.129-143
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• 2022

Background: Patient-controlled analgesia (PCA) has been widely used as an effective medical treatment for pain and for postoperative analgesia. However, improper dose errors in intravenous (IV) administration of narcotic analgesics from a PCA infusion pump can cause patient harm. Furthermore, opioid overdose is considered one of the highest risk factors for patients receiving pain medications. Therefore, accurate delivery of opioid analgesics is a critical function of PCA infusion pumps. Methods: We designed a microbalance method that consisted of a closed acrylic chamber containing a layer and an oil layer with an electronic balance. A commercially available infusion analyzer (IDA-5, Fluke Co., Everett, WA, USA) was used to measure the accuracy of the infusion flow rate from a commercially available smart PCA infusion pump (PS-1000, UNIMEDICS, Co., Ltd., Seoul, Korea) and compared with the results of the microbalance method. We evaluated the uncertainty of the flow rate measurement using the ISO guide (GUM:1995 part3). The battery life, delay time of the occlusion alarm, and bolus function of the PCA pump were also tested. Results: The microbalance method was good in the short-term 2 h measurement, and IDA-5 was good in the long-term 24 h measurement. The two measurement systems can complement each other in the case of the measurement time. Regarding battery performance, PS-1000 lasted approximately 5 days in a 1 ml/hr flow rate condition without recharging the battery. The occlusion pressure alarm delays of PS-1000 satisfied the conventional alarm threshold of occlusion pressure (300-800 mmHg). Average accuracy bolus volume was measured as 63%, 95%, and 98.5% with 0.1 ml, 1 ml, and 2 ml bolus volume presets, respectively. A 1 ml/hr flow rate measurement was evaluated as 2.08% of expanded uncertainty, with a 95% confidence level. Conclusion: PS-1000 showed a flow accuracy to be within the infusion pump standard, which is ± 5% of flow accuracy. Occlusion alarm of PS-1000 was quickly transmitted, resulting in better safety for patients receiving IV infusion of opioids. PS-1000 is sufficient for a portable smart PCA infusion pump.

• 분석과학
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• 제21권6호
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• pp.502-509
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• 2008

혈청 내 콜레스테롤을 정량분석하기 위한 일차분석법으로 동위원소희석 액체크로마토그래피/질량분석법(isotope dilution liquid chromatography/mass spectrometry)을 사용하였다. 콜레스테롤은 Thermo ODS hypersil $C^{18}$ 칼럼을 사용하여 분리하였고, 이동상은 100% 메탄올, 유속은 0.3 mL/min으로 하였다. 콜레스테롤과 콜레스테롤-$3,4-13C_2$는 $[M-H_2O+H]^+$이온에 해당하는 m/z 369.4와 371.3에서 모니터링하여 정량에 합당한 크로마토그램을 얻을 수 있었다. 방법의 유효성을 증명하기 위해서 NIST SRM 909b를 분석한 결과 인증값과 불확도 범위 내에서 일치하는 것을 확인하였다. 이 방법을 바탕으로 혈청 인증표준 물질 4 종류를 제조하여 인증을 실시하였다. 인증 결과, 반복성의 상대표준오차는 0.1~0.8%, 재현성의 경우 0.24%이하, 확장 불확도는 95% 신뢰도구간에서 약 1.43%로 나타났다.

• 분석과학
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• 제22권4호
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• pp.302-306
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• 2009

철강 중의 미량 붕소는 소재의 기계적, 물리적 특성에 중요한 영향을 준다. 즉발감마선 방사화 분석법에 의해 저합금강 시료 중의 미량 붕소를 측정하였다. 시료는 한국표준과학연구원에서 제조한 저합금강 표준물질KRISS 101-01-C21~C26을 이용하였으며, 측정방법의 유효성 확인을 위해 NIST SRM 362, 364, 1761, 1762를 정확도관리용 시료로 사용하였다. NIST SRM 362를 제외하고는 측정 농도가 인증값의 불확도 범위내에서 잘 일치하였다. 불확도는 ISO guideline에 따라 평가하였으며, 포함인자 2를 적용하여 확장불확도를 산출하였다. 붕소 농도 mg/kg수준에서 상대확장불확도는 3%에서 7% 사이였다. 그 결과를 용매추출-유도결합플라스마 방출분광분석결과와 비교하여 제시하였다.

• Journal of Information Technology Applications and Management
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• 제15권4호
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• pp.159-188
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• 2008

This study suggests strategies which can enable to creation of new opportunities of competitive advantages while operating a long lasting and consistent business with major trading partners, based on interorganizational information systems (IOISs) specially established and installed for interorganizational transactions. Nowadays, IOISs based mechanism having been widely expanded as a conventional business infrastructure for the interorganizational transactions and/or exchanges, it is customary difficult to obtain any strongly sound advantage over the competitors who have adopted even the simplest deployment of the IOIS mechanisms. In this connection, this study intends to investigate the interorganizational collaborative activities conducted by under the auspicious of IOISs, focused on the prospect of the exploitation of IOISs rather than the implementation of the IOISs. In this study, we, firstly, suggest the concept of Electronic Collaboration which can be defined by the collaborative activities conducted by IOISs, compared to the ones conducted on off-line. In addition, we suggest the Electronic Collaboration as a multi-dimensional concept, constituted by three sub-constructs, the Electronic Information Sharing (EIS), the Electronic Joint Activity (EJA), and the construction of the Electronic Relational Knowledge Store (ERKS). Secondly, we empirically verify the effects of relational and environmental determinants on the Electronic Collaboration. In this study, the relational determinants relate to the variables created in interorganizational relationship like Trust, Influence, Relational Specific Asset-asset invested for the transaction-, and Continuity of the relationship. On the other hand, the environmental determinants relate to the variables surrounding the relationship which are difficult to control. We consider Product Complexity, Technological Uncertainty, and Market Variability as the domain of the environmental determinants. To test our hypotheses, we conducted both paper-based survey and online-based survey. After refining the data with missing responses, a total of 150 data was used for analysis. The results were as follows : Firstly, it is statistically significant that the Electronic Collaboration is composed of EIS, EJA, and ERKS. In particular, the results imply that the firms are able to accumulate relational knowledge base as well as to exchange information or knowledge, and to conduct joint activities through effort to further expand the Electronic Collaboration. Secondly, we have verified the individual effects of the relational and the environmental determinants on the Electronic Collaboration. Product Complexity has been revealed as the most influential variable affecting the Electronic Collaboration. Next, Interorganizational Trust and Technological Uncertainty, in that order, have been seen to have significant effects on the Electronic Collaboration. In other words, when products or services seem to be difficult to standardize, and the core technologies seem to rapidly change, the need for the Electronic Collaboration increase. In addition, the observation dictates that the interorganizational trust turns out to be a critical variable in building a relationship and in seeking further collaboration. The results, further, illustrate that the environmental determinants are relatively more effective than the relational determinants, which is not consistent with a few prior researches relational determinants emphasized. It is because this study doesn't consider the size of the firm. A few researchers have given an emphasis on the relational determinants like trust and influence, especially from the perspective of small firms in interorganizational relationship. However, in our study, where all the sizes of the firms are contained, electronic collaboration is considerably affected by the environmental determinants.

• 한국가스학회지
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• 제22권2호
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• pp.46-51
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• 2018

산업이 급속하게 발전함에 따라 자연 대기에서 악취를 유발하는 매우 적은 양의 황화수소가 존재합니다. 매립 및 하폐수처리장에서 나오는 황화수소 성분은 대기에 존재하므로 많은 민원이 발생됩니다. 민원이 발생하는 악취가스를 측정하기 위해 $10{\mu}mol/mol$ 농도 수준의 황화수소 인증표준물질(Certified reference material)을 개발하고자 하였다. 질소 안에 $10{\mu}mol/mol$ 수준의 황화수소 가스 제조는 ISO 6142에 의한 중량법을 사용하였다. 4 개의 알루미늄 실린더에 가스 CRM을 제조하고 GC-AED로 그 농도를 확인했습니다. 제조의 불확도는 0.50 % 미만이었고, 제조일치성은 0.22 %이었다. 실린더의 내부 흡착은 1500 psi에서 0.10 %이었고 1 년 동안 장기간 안정한 것으로 평가되었다. 이 황화수소 CRM의 제조 일치성, 실린더의 흡착 및 장기 안정성에 대한 상대 확장불확도는 1.05 %(신뢰도 95 %, k = 2) 이내로 개발되었다.

• 한국산림과학회지
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• 제100권3호
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• pp.315-326
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• 2011

최근 기후변화와 관련하여 국내를 비롯한 국제적인 관심이 증폭되고 있으며, 이러한 시대적인 흐름 속에 탄소흡수원으로서의 산림의 중요성이 부각되고 있다. 특히, 산림전용 및 황폐화 방지를 통한 온실가스감축(Reduced Emissions from Deforestation and Degradation, REDD) 및 산림탄소축적보존 및 증진, 지속가능한 산림경영을 포함하는 REDD+가 post-2012에 이행될 신규 메커니즘으로 활용될 전망이다. 메커니즘의 이행을 위해서는 기본적으로 MRV(Measuring, Reporting and Verification) 시스템을 통해 메커니즘 적용 효과를 인증 받아야 한다. 본 연구에서는 가장 효율적인 모니터링 방법 중 하나로 인정받고 있는 다양한 원격탐사기술의 토지피복변화 탐지 및 탄소축적량 추정하는 방법 및 효과를 비용 및 기술(불확실성)측면에서 분석하였다. 그 결과 토지피복변화탐지를 위해서는 중해상도 광학영상 및 위성 탑재 SAR(Synthetic Aperture Radar)가 가장 적합한 원격탐사자료로 도출되었다. 그리고 탄소축적량 추정에 있어서는, 항공기 탑재 LiDAR(Light Detection and Ranging), SAR와 같이 불확실성이 낮은 기술과 비용효율적인 기술인 중해상도 광학영상, 위성 탑재 SAR 간의 통합을 통해 효율적인 결과를 도출할 수 있음을 확인할 수 있었다. 하지만, 아직까지 본 메커니즘에 대한 명확한 인증기관, 가이드라인 및 불확실성에 대한 기준이 결정 되지 않고 있으므로, 추후 지속적인 관심을 통해 국제적인 흐름을 파악하고, 적합한 방법론을 구축해야 한다. 뿐만 아니라 개발된 메커니즘을 대상 개도국에 활용하기 위해서는 긴밀한 국제협력관계 구축 및 대상국에 적합한 모니터링 방법 또한 고려해야 할 필요성이 있다.

• 한국식품위생안전성학회지
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• 제26권2호
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• pp.142-149
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• 2011

본 연구에서는 면류에서 면역친화컬럼을 이용한 데옥시니발레놀의 HPLC분석법을 검증하고, 분석과정에서 발생될 수 있는 불확도를 GUM 지침에 따라 측정하였다. 검출한 계와 정량한계는 7.5 ${\mu}g$/kg과 18.8 ${\mu}g$/kg이었고 검량선은 20~500 ${\mu}g$/kg 농도범위 에서 0.9999의 높은 상관성을 보였다. 대표적인 밀 가공품인 건면과 라면에 데옥시니 발레놀을 200 ${\mu}g$/kg과 500 ${\mu}g$/kg을 첨가하여 회수율과 반복성올 측정한 결과, 건면에서는 $82{\pm}2.7%$와 $87{\pm}1.3%$의 결과를 얻었고, 라면에서는 $97{\pm}1.6%$와 $91{\pm}12.0%$로 측정되었다. 한편, 불확도 측정을 위한 첫 단계로, 분석과정에서의 불확도 요인은 시료량 측정, 최종 시료부피, 보관표준용액, 작업표준용액, 표준용액, 기기, 매질, 검량선 작성으로 구분하였다. 불확도 요인의 구성요인은 저울의 안정성, 분해능, 재현성, 표준물질의 순도, 분자량, 농도, 표준용액 희석, 검량선, 회수율 및 분석기기의 재현성 풍이 작용하였다. 건면과 라면에 데옥시니발레놀을 200과 500 ${\mu}g$/kg을 첨가하여 분석한 결과 건면에서는 $163.8{\pm}52.1\;{\mu}g$/kg, $435.2{\pm}91.6\;{\mu}g$/kg으로 측정되었고 라면에서는 $194.3{\pm}33.0\;{\mu}g$/kg, $453.2{\pm}91.1\;{\mu}g$/kg으로 측정되었다. 확장불확도는 합성표준불확도에 포함인자(k=2, 신뢰수준 95%)를 곱하여 산출하였다. 건면과 라면에서 데옥시니발레놀을 분석함에 있어 불확도에 영향을 주는 주요인자는 시료의 회수율과 검량선 작성인 것으로 파악되었다. 따라서 면류 시료에서 데옥시니발레놀 것으로 분석의 정밀성을 높이기 위해서는 회수율과 검량선 작성에 영향을 끼칠 수 있는 분석과정을 확인하고 오차를 최소화 할 수 있는 방안을 모색해야 할 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.543-551
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• 2001

The vascular endothelial growth factor (VEGF), or VEGF-A, is intimately involved in both physiological and pathological forms of angiogenesis. VEGF-A is now recognized as the founding member of a family of growth factors that has expanded to include VEGF-B, VEGF-C, VEGF-D, VEGF-E, and placental growth factor (PIGF). This family of cytokines binds differentially to at least three receptor tyrosine kinases, however, the extent to which family members other than VEGF-A contribute to physiological and pathological angiogenesis remains unclear. Issues that are of relevance include uncertainty regarding the consequences of signaling through VEGF - RI in particular, and the ability of some family members to heterodimerize, leading to the possibility ofheterodimeric receptor complexes. Structural characterization is one approach that can be used to address these issues, however, the vast majority of previous structure-function studies have only focused on VEGF-A. While these studies may provide some clues regarding the structural basis of the interaction of other family members with their receptors, studies using the ligands themselves are clearly required if highly specific interactions are to be revealed. With the recent progress toward refolding and purifying substantial' quantities of other VEGF family members, such structural studies are now possible. Here, these ~ssues are addressed with a particular emphasis on VEGF-B and its receptors.