• Tuberculosis and Respiratory Diseases
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• 제61권4호
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• pp.356-365
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• 2006

연구배경: 패혈증에서 혈중 스테로이드 농도는 유의한 예후인자로서 알려져 있다. 또한 최근에는 이러한 스테로이드의 절대적 및 상대적 결핍 현상이 알려지고 있으며, 이는 스테로이드 보충 치료의 지표로도 이용되고 있다. 본 연구에서는 패혈증 환자에서 혈중 스테로이드 농도, 24시간 뇨 스테로이드 양 및 상대적 부신결핍의 임상적 의의와 기타 패혈증의 혈중 지표와의 연관성에 대하여 알아보고자 하였다. 방 법: 패혈증 환자 26예를 대상으로 초기 혈중 스테로이드와 ACTH, ADH, lactate 등의 농도를 측정하고 24시간 뇨 유리 코티졸 양을 측정하였으며, rapid ACTH stimulation test를 시행하였다. 결 과: 패혈증 환자들에서 사망군은 생존군에 비해 기저 무작위 혈청 코티졸 농도가 유의하게 증가되어 있었다. 중증패혈증 환자들에서 24시간 뇨 유리 코티졸은 경증패혈증 환자군에 비해 유의하게 증가되어 있었다. 혈청 코티졸 농도는 ADH, lactate농도와 유의한 상관관계를 나타내었고, 24시간 뇨 유리 코티졸은 혈청 코티졸, lactate 농도와 유의한 상관관계를 보였다. 상대적 부신결핍의 정도는 혈청 코티졸, ADH, lactate 농도와 상관성이 있었다. 결 론: 패혈증 환자들에서 혈청 코티졸 농도 및 24시간 뇨 유리 코티졸은 유의한 예후평가인자로서 나타났으며, 기타 예후 인자들과 유의한 상관성을 보였다. 상대적 부신 결핍의 정도도 유의한 중증도의 지표로 나타났다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.495-501
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• 1997

A preliminary and parametric sensitivity study on recriticality risk of fast reactor cores after a hypothetical total core meltdown accident was performed. Only neutronic aspects of the accident were considered, independent of the accident scenario, and efforts were made to estimate the quantity of molten fuel which must be ejected out of the core to assure a sub-critical state after the accident. Two types of parameters were examined : characteristic parameters of molten core such as geometry, molten pool type (homogenized or stratified), fuel temperature, environment, and relative parameters to normal core such as core size(small or large), and fuel type (oxide, nitride, metal). The first type of parameters was found to intervene more directly in the recriticality risk than the second type of parameters.

• 조명전기설비학회논문지
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• 제26권6호
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• pp.59-65
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• 2012

This paper presents a digital control solution which can extract the reactor parameters in atmosphere plasma power supply. The critical issue of the atmosphere plasma power supply is a impedance matching. For the impedance matching, the reactor parameters should be known, but the parameters depend on the reactors. Therefore, the reactor parameters have to measure for the impedance matching. The proposed method is performed by detection of phase difference between inverter voltage and current, and extraction of impedance through active, reactive power.

• 한국정밀공학회지
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• 제26권6호
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• pp.122-130
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• 2009

The analysis of human movement requires the knowledge of the Hill type muscle parameters, the muscle-tendon and moment arm length change as a function of joint angles. However, values of a subject's muscle parameters are very difficult to identify. It turns out from a sensitivity analysis that the tendon slack length and maximum muscle force are the two critical parameters among the Hill-type muscle model. Therefore, it could be claimed that the variation of the tendon slack length and maximum muscle force from the Delp's reference data will change the muscle characteristics of a subject remarkably. A numeric optimization method to search these tendon parameters specific to a subject is proposed, and the accuracy of the developed algorithm is evaluated through a numerical simulation.

• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.470-477
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• 2000

The states of control loops in existing actual systems are changed according to time varying conditions of controllest process and other system components. Adjusting control parameters properly at site which is performed generally by Ziegler & Nichols mthod is important for safe and efficient operation, but the method may require much time to adjust and not easy to inexperienced engineers. This study is aimed to propose more handy method to adjust control parameters by plotting operating conditions on the space of adjusting parameters. One loop of model control system without perturbation condition has been adopted and its stability limit was plotted on the coordinates of Gain and Integral time which was acquired after analyzing Nyquist diagrams and time domain responses. The result showed that the sets of adjusting parameters according to critical stability and proper stability could be acquired reasonably through both responses and the curves on parameter space revealed available patterns for the purpose of easy maintenance of control characteristics.

• 아태비즈니스연구
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• 제4권2호
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• pp.21-30
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• 2013

Ethics involves distinguishing between what is right or wrong thereby making a correct choice. An organization should treat its internal as well as external stakeholders ethically. This research gives valuable insights on the prevailing ethical climate and potential organizational challenges in institutionalizing ethics and its management in the manufacturing sector. The present study is designed to analyze four parameters of ethical climate in the manufacturing sector with reference to different managerial levels, to identify the critical factor of the ethical code of conduct and to find correlations between four parameters of ethical climate. Descriptive research has been used and data are collected from 200 employees of three Indian companies of manufacturing sector using a well designed questionnaire. Analyzing data with SPSS, It has been found that overall good number of people believe that MBE (Management of Business Ethics) process is well implemented. People are well aware and trained and involved in the ethical process. Senior management is very much committed to promote the ethical environment in the organization and thus company values are well communicated to the employees. Concern resolution mechanism is well established in the organization. MBE in the organization is more prevalent in higher-level employees. Senior management commitment and reinforcement is very critical for CoC (code of conduct). Correlation between all the 4 parameters is positive and significant. But the parameters are not highly correlated with each other. Organizations need to work upon these parameters to promote an ethical climate in the organization by awarding or felicitating exemplary ethical behavior. More emphasis should be given on senior management commitment and reinforcement of the ethical behavior across all levels.

• 한국지반신소재학회논문집
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• 제12권1호
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• pp.11-19
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• 2013

조립재료는 댐, 철도, 교량 구조물 건설시 제체, 성토재, 뒤채움재, 배수재 등으로 널리 사용되고 있으며, 이러한 구조물의 거동해석을 위한 수치해석을 위해 구성모델에 대한 연구가 다양하게 진행되어 왔다. 본 논문에서는 조립재료의 거동을 예측하기 위해 개발된 구성모델에 대한 변수 연구를 수행하였다. 구성모델은 한계상태이론에 근간한 bounding surface 모델로서 한 세트의 모델 정수를 활용하여 배수 조건, 구속압, 간극비에 상관없이 조립재료의 거동을 구현할 수 있는 장점을 지니고 있다. 구성모델은 탄성 파라미터, 한계상태 파라미터, 모델 고유파라미터를 활용하여 재료의 거동을 분석하며, 본 연구에서는 모델 고유 파라미터에 대한 변수 연구를 수행하였다. 변수 연구를 통해 구성모델이 조립재료의 가장 큰 특징인 비관계유통법칙(non-associative flow rule)에 따른 체적팽창 및 응력경로 변화에 따른 이동경화 현상을 적절히 모사할 수 있음을 파악하였다.

• Journal of Trauma and Injury
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• 제36권3호
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• pp.210-216
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• 2023

Purpose: This preliminary retrospective cohort study analyzed the relationship between the parameters provided by sonorheometry device Quantra and the coagulation values obtained from standard venous blood samples in patients admitted in intensive care unit (ICU). Methods: We reviewed medical charts of 13 ICU adult patients in whom at least one coagulation study with Quantra was performed. The relationship between Quantra and laboratory data was analyzed with the Spearman rank correlation coefficient (rho). The 95% confidence interval (CI) was computed. A P-value <0.05 was considered statistically significant. Results: We collected 28 data pairs. Statistically significant moderate correlations were found for the following parameters: clot time (CT) and activated partial thromboplastin time (rho=0.516; 95% CI, 0.123-0.904; P=0.009; clot stiffness (CS) and the international normalized ratio (INR; rho=0.418; 95% CI, 0.042-0.787; P=0.039); INR and platelet contribution to CS (rho=0.459; 95% CI, 0.077-0.836; P=0.022); platelet count and platelet contribution to CS (PCS; rho=0.498; 95% CI, 0.166-0.825; P=0.008); and fibrinogen and fibrinogen contribution to CS (FCS; rho=0.620; 95% CI, 0.081-0.881; P=0.001). Conclusions: Quantra can provide useful information regarding coagulation status, showing modest correlations with the parameters obtained from laboratory tests. During diffuse bleeding, CT and FCS values can guide the proper administration of clotting factors and fibrinogens. However, the correlation of INR with CS and PCS can cause misinterpretation. Further studies are needed to clarify the relationship between Quantra parameters and laboratory tests in the critical care setting and the role of sonorheometry in guiding targeted therapies and improving outcomes.

• Tuberculosis and Respiratory Diseases
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• 제73권3호
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• pp.151-161
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• 2012

Background: Adequate assessment and control of sedation play crucial roles in the proper performance of mechanical ventilation. Methods: A total of 30 patients with various pulmonary diseases were prospectively enrolled. The study population was randomized into two groups. The sedation assessment group (SAG) received active protocol-based control of sedation, and in the empiric control group (ECG), the sedation levels were empirically adjusted. Subsequently, daily interruption of sedation (DIS) was conducted in the SAG. Results: In the SAG, the dose of midazolam was significantly reduced by control of sedation (day 1, $1.3{\pm}0.5{\mu}g/kg/min$; day 2, $0.9{\pm}0.4{\mu}g/kg/min$; p<0.01), and was significantly lower than the ECG on day 2 (p<0.01). Likewise, on day 2, sedation levels were significantly lower in the SAG than in the ECG. Significant relationship was found between Ramsay sedation scale and Richmond agitation-sedation scale (RASS; $r_s$=-0.57), Ramsay Sedation Scale and Bispectral Index (BIS; $r_s$=0.77), and RASS and BIS ($r_s$=-0.79). In 10 patients, who didn't require re-sedation after DIS, BIS showed the earliest and most significant changes among the sedation scales. Ventilatory parameters showed significant but less prominent changes, and hemodynamic parameters didn't show significant changes. No seriously adverse events ensued after the implementation of DIS. Conclusion: Active assessment and control of sedation significantly reduced the dosage of sedatives in patients receiving mechanical ventilation. DIS, conducted in limited cases, suggested its potential efficacy and tolerability.

• 한국광물학회지
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• 제30권4호
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• pp.161-172
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• 2017

점토광물은 지하수 바닥부터 산림에 이르는 지구의 얇은 표면에 해당하는 '크리티컬존(critical zone)'에 존재하는 금속원소의 지구화학적 순환에 중요한 역할을 한다. 입자 크기가 매우 작은 점토광물에 대한 원자 수준(atomistic scale)의 연구는 지구화학적 순환 과정에 대한 정확한 기작(mechanism)을 규명할 수 있을 뿐만 아니라 재료개발과 같은 산업분야에도 응용될 수 있다. 원자 간의 페어 퍼텐셜(pair potential)을 파라미터화한 힘 장(force field)을 사용하는 분자동역학(molecular dynamics) 컴퓨터 시뮬레이션은 원자 수준의 정보를 제공할 수 있기 때문에 실험과 함께 점토광물의 결정구조와 반응도 연구에 사용된다. 점토광물 시뮬레이션을 위한 힘 장으로는 이팔면체(dioctahedral) 광물을 기반으로 만들어진 ClayFF 힘 장이 보편적으로 사용된다. 삼팔면체(trioctahedral) 광물 시뮬레이션에도 ClayFF를 사용하는 연구가 보고되고 있으나, 같은 광물을 계산하더라도 각 연구마다 다른 파라미터 값을 사용하고 있기 때문에 파리미터 선택이 시뮬레이션의 정확도에 어떤 영향을 미치는지 체계적인 테스트가 필요하다. 이번 연구에서는 삼팔면체 광물인 수활석, 리자다이트, 활석을 대상으로 팔면체 마그네슘(Mg)의 원자간 페어 퍼텐셜을 나타내는 파라미터 'mgo'와 'mgh'를 각각 사용하여 분자동역학 시뮬레이션 계산결과를 비교하였다. 격자상수, 원자 간의 거리 등 삼팔면체 점토광물의 결정구조는 주어진 두 가지 파라미터에 관계없이 거의 일정한 결과를 보여주었지만, 진동 파워 스펙트럼(vibrational power spectrum)으로 계산한 수산기의 진동수는 파라미터에 따라 상대적으로 뚜렷한 차이를 보였다.