• 한국임상약학회지
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• 제18권1호
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• pp.60-67
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• 2008

This study aimed to compare a microparticle enzyme immunoassay (MEIA) with a liquid chromatography-tandem mass spectrometry (LC/MS/MS) technique for the measurement of tacrolimus concentrations in adult liver transplant recipients, to investigate how the assay choice influenced the population pharmacokinetics of tacrolimus and to identify patient characteristics that affected pharmacokinetic parameters in each assay. Tacrolimus concentrations from 29 liver (n=52 paired-samples) transplant recipients measured by both MEIA and LC/MS/MS were used to evaluate the performance of these methods in the clinical setting. Tacrolimus pharmacokinetics was studied independently using MEIA and LC/MS/MS data in 70 adult patients using a population approach performed with NONMEM. Patient characteristics which influenced pharmacokinetic parameters in each assay were compared. The relation between LC/MS/MS and MEIA measurements was best described by the regression equation MEIA=1.465*LC/MS/MS-1.336 (r=0.91). Multiple linear regression analysis showed significant inverse relationships between assay difference and hematocrit (Hct) (p<0.025) in liver graft recipients. In MEIA, the population estimate of tacrolimus CL/F and apparent volume of distribution (Vd/F) were found to be 10.1 L/h and 226 L, and in LC/MS/MS, 13 L/h and 305 L respectively. Neither patient's age, weight, gender, grafted hepatic weight, albumin concentration, nor markers of liver function influenced tacrolimus CL/F The final model of CL/F was found to be 10.1+(Hct/Hct mean)$^{12.0}$ in MEIA and 13+(1+Hct/578) in LC/MS/MS indicating that CL/F was influenced by hematocrit.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.407-417
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• 2003

최근 구조최적화분야에서 활발하게 사용되고 있는 유전알고리즘은 해집단을 운용하기 때문에, 많은 반복수와 적응도 평가를 위하여 해집단의 수에 해당하는 구조해석을 필요로 하며, 또한 교배율과 돌연변이율 등의 파라미터에 따라 알고리즘의 성능이 변화하므로 문제에, 따라 적합한 파라미터 설정이 필요한 근본적인 단점을 지니고 있다. 본 연구에서는 기존 유전알고리즘의 단점을 극복할 수 있는 복합유전알고리즘을 마이크로유전알고리즘과 단순유전알고리즘을 결합한 형식으로 그리고, 최적화에 요구되는 연산을 다수의 개인용 컴퓨터에서 동시에 분산하여 수행할 수 있는 고성능 분산 복합유전알고리즘으로 개발하였다. 개발된 알고리즘은 철골 가새골조 구조물의 최소중량설계에 적용하여 그 성능을 평가하였다.

• 대한전자공학회논문지TC
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• 제38권4호
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• pp.1-10
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• 2001

W-CDMA 시스템에서 각 셀마다 고유하게 할당된 스크램블링 부호의 신속한 획득을 위해 3 단계 셀 탐색 기법의 사용이 고려되어 왔다. 본 논문에서는 레일리 페이딩 채널에서 초기 셀 탐색 기법의 성능을 해석한다. 셀 탐색 방법에 대한 시스템 파라미터와 수신기의 설계 파라미터의 영향을 고찰한다. 각 단계마다 검파 확률과 실패 확률, 오경보 확률을 CDMA 넌코히런트 복조기 출력의 통계량을 근거로 하여 closed form으로 유도하였다. 해석을 통해 각 단계의 임계값과 사후 검파 적분의 효과를 고찰하였으며, 동기 채널들에 대한 최적의 전력비를 고찰하였다. 각 단계에 대한 사후 검파 적분의 횟수는 수신기에 대한 설계 파라미터이며, 그 최적값은 셀 탐색을 위한 채널의 전력 할당비 뿐 아니라 오경보 패널티 시간 등에 의존한다. 이들 파라미터의 최적값을 얻기 위해 본 논문의 해석이 사용될 수 있음을 보인다. 또한 해석을 통해 평균 셀 탐색 시간의 누적 확률 분포를 얻는다.

• 한국통신학회논문지
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• 제30권4B호
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• pp.218-225
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• 2005

Snoop 프로토콜은 유무선이 통합된 망에서 효율적으로 TCP 전송률을 향상시킬 수 있는 프로토콜이지만 연속적인 패킷 손실이 발생하는 무선 링크에서 사용되는 경우 지역 재전송을 비효율적으로 수행하는 문제점이 있다. AT-Snoop 프로토콜은 Snoop 프로토콜을 기반으로 하면서 Adaptive Timer를 사용하여 이러한 Snoop 프로토콜의 단점을 개선한 프로토콜이다. 본 논문에서는 AT-Snoop 프로토콜의 TCP 전송률 성능을 무선 링크 환경을 변화시키면서 분석하구 각 무선 링크 환경에서 향상된 TCP 전송률을 얻기 위한 AT-Snoop 프로토콜의 파라미터 값들을 도출하였다. 컴퓨터 시뮬레이션을 통해 AT-Snoop 프로토콜의 두 파라미터인 지역 재전송 임계값과 지역 재전송 시간값이 무선 링크에서의 페이딩의 변화 속도와 밀접한 관계가 있음을 확인할 수 있었다. 지역 재전송 임계값은 무선 링크의 평균 WSRTT(Wireless Smoothed Round Trip Time)보다, 지역 재전송 시간은 무선 링크의 평균 불량 기간보다 각각 약간 크게 설정하는 것이 AT-Snoop 프로토콜을 사용할 때 높은 TCP 전송률을 얻을 수 있었다.

• Wind and Structures
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• 제21권4호
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• pp.407-424
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• 2015

To explore the favorable structural system of cable-stayed bridges with ultra-kilometer main span, based on a fully self-anchored cable-stayed bridge with 1400 m main span, a partially earth-anchored cable-stayed bridge scheme with the same main span is designed. Numerical investigation on the dynamic characteristics, aerostatic and aerodynamic stability of both two bridge schemes is conducted, and the results are compared to those of a suspension bridge with similar main span, and considering from the aspect of wind stability, the feasibility of using partially earth-anchored cable-stayed bridge in super long-span bridges with ultra-kilometer main span is discussed. Moreover, the effects of structural design parameters including the length of earth-anchored girder, the number of auxiliary piers in side span, the height and width of girder, the tower height etc on the dynamic characteristics, aerostatic and aerodynamic stability of a partially earth-anchored cable-stayed bridge are analyzed, and their reasonable values are proposed. The results show that as compared to fully self-anchored cable-stayed bridge and suspension bridge with similar main span, the partially earth-anchored cable-stayed bridge has greater structural stiffness and better aerostatic and aerodynamic stability, and consequently becomes a favorable structural system for super long-span bridges with ultra-kilometer main span. The partially earth-anchored cable-stayed bridge can achieve greater stiffness and better wind stability under the cases of increasing the earth-anchored girder length, increasing the height and width of girder, setting several auxiliary piers in side span and increasing the tower height.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.344-349
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• 2018

본 논문은 의료용 시술에 사용되는 가이드 와이어의 테프론 코팅 장치의 주요 설계변수 설정방법에 대해 제안하였다. 제안된 장치는 가이드 와이어가 코팅 및 열처리 등을 연속적으로 수행하는 릴투릴(Reel to reel)방식으로 진행되도록 제작되었다. 이때 이송되는 가이드 와이어는 롤러 사이에서 진동을 하게 되고 이는 코팅 품질에 영향을 주게 된다. 따라서 본 논문에서는 길이방향으로 이송되는 가이드 와이어의 동역학 식을 제안하고 이를 바탕으로 이송 시 가이드 와이어의 진동 진폭이 최소화 될 수 있는 이송 속도 및 와이어를 지지하는 롤러의 간격을 설계하였다. 제안된 방법에 의해 제작된 코팅 장치를 바탕으로 의료용 가이드 와이어의 테프론 코팅을 진행하였다. 본 연구에서는 가이드 와이어의 코팅 두께 목표를 원주방향으로 $10{\mu}m$ 이내로 제작될 수 있도록 설정하였고 광학현미경을 사용하여 그 결과를 검토하였다.

• 여성건강간호학회지
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• 제27권2호
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• pp.75-92
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• 2021

Purpose: This study aimed to analyze the content and effectiveness of psychosocial support interventions for women with gestational diabetes mellitus (GDM). Methods: The following databases were searched with no limitation of the time period: Ovid-MEDLINE, Cochrane Library, Ovid-Embase, CINAHL, PsycINFO, NDSL, KoreaMed, RISS, and KISS. Two investigators independently reviewed and selected articles according to the predefined inclusion/exclusion criteria. ROB 2.0 and the RoBANS 2.0 checklist were used to evaluate study quality. Results: Based on the 14 selected studies, psychosocial support interventions were provided for the purpose of (1) informational support (including GDM and diabetes mellitus information; how to manage diet, exercise, stress, blood glucose, and weight; postpartum management; and prevention of type 2 diabetes mellitus); (2) self-management motivation (setting goals for diet and exercise management, glucose monitoring, and enhancing positive health behaviors); (3) relaxation (practicing breathing and/or meditation); and (4) emotional support (sharing opinions and support). Psychosocial supportive interventions to women with GDM lead to behavioral change, mostly in the form of self-care behavior; they also reduce depression, anxiety and stress, and have an impact on improving self-efficacy. These interventions contribute to lowering physiological parameters such as fasting plasma glucose, glycated hemoglobin, and 2-hour postprandial glucose levels. Conclusion: Psychosocial supportive interventions can indeed positively affect self-care behaviors, lifestyle changes, and physiological parameters in women with GDM. Nurses can play a pivotal role in integrative management and can streamline the care for women with GDM during pregnancy and following birth, especially through psychosocial support interventions.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.699-706
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• 2022

In this study, Directed energy deposition (DED) among additive manufacturing is applied to repair damaged spindle key parts of planner miller. The material of the spindle key is SCM415, and the P21 Powder is used. In order to find the optimal deposition conditions for DED equipment, a single-line deposition experiment is conducted to analysis five parameters. The laser power affects the width, and the height is a parameter affected by coaxial gas and powder gas. In addition, laser power, powder feed rate, coaxial gas, and powder gas are parameters that affect dilution. Otimal deposition is that 400 W of laser power, 4.0 g/min of powder feed rate, 6.5 L/min of coaxial gas, 3.0 L/min of powder gas and 4.5 L/min of shield gas. By setting the optimum conditions, a uniform deposition cross section in the form of an ellipse can be obtained. Damage recovery process of spindle key consists of 3D shape design of the base and deposition parts, deposition path creation and deposition process, and post-processing. The hardness of deposited area with P21 powder on the SCM415 spindle key is 336 HV for the surface of the deposition, 260 HV for the boundary area, and 165 HV for the base material.

• 대한방사선기술학회지:방사선기술과학
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• 제46권3호
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• pp.239-246
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• 2023

In this study, we assessed the effect of reduction of tumor volume in the head and neck cancer by using RANDO phantom in Static Intensity-Modulated Radiation Therapy (S-IMRT) and Volumetric-Modulated Arc Therapy (VMAT) planning. RANDO phantom's body and protruding volumes were delineated by using Contour menu of Eclipse™ (Varian Medical System, Inc., Version 15.6, USA) treatment planning system. Inner margins of 2 mm to 10 mm from protruding volumes of the reference were applied to generate the parameters of reduced volume. In addition, target volume and Organ at Risk (OAR) volumes were delineated. S-IMRT plan and VMAT plan were designed in reference. These plans were assigned in the reduced volumes and dose was calculated in reduced volumes using preset Monitor unit (MU). Dose Volume Histogram (DVH) was generated to evaluate treatment planning. Conformity Index (CI) and R² in reference S-IMRT were 0.983 and 0.015, respectively. There was no significant relationship between CI and the reduced volume. Homogeneity Index (HI) and R² were 0.092 and 0.960, respectively. The HI increased when volume reduced. In reference VMAT, CI and R² were 0.992 and 0.259, respectively. There was no relationship between the volume reduction and CI. On the other hand, HI and R² were 0.078 and 0.895, respectively. The value of HI increased when the volume reduced. There was significant difference (p<0.05) between parameters (D_mean and D_max) of normal organs of S-IMRT and VMAT except brain stem. Volume reduction affected the CI, HI and OAR dose. In the future, additional studies are necessary to incorporate the reduction of the volume in the clinical setting.

• Journal of Korean Neurosurgical Society
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• 제66권4호
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• pp.382-392
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• 2023

Objective : The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. Methods : We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. Results : The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters-growth and decay rates, and peak center and heights-of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. Conclusion : The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.