• Applied Science and Convergence Technology
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• 제24권5호
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• pp.196-202
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• 2015

Human blood consists of 55% of plasma and 45% of blood cells such as white blood cell (WBC) and red blood cell (RBC). In plasma, there are many kinds of promising biomarkers, which can be used for the diagnosis of various diseases and biological analysis. For diagnostic tools such as a lab-on-a-chip (LOC), blood plasma separation is a fundamental step for accomplishing a high performance in the detection of a disease. Highly efficient separators can increase the sensitivity and selectivity of biosensors and reduce diagnostic time. In order to achieve a higher yield in blood plasma separation, we propose a novel fluid wing structure that is optimized by COMSOL simulations by varying the fluidic channel width and the angle of the bifurcation. The fluid wing structure is inspired by the inertial particle separator system in helicopters where sand particles are prevented from following the air flow to an engine. The structure is ameliorated in order to satisfy biological and fluidic requirements at the micro scale to achieve high plasma yield and separation efficiency. In this study, we fabricated the fluid wing structure for the efficient microfluidic blood plasma separation. The high plasma yield of 67% is achieved with a channel width of $20{\mu}m$ in the fabricated fluidic chip and the result was not affected by the angle of the bifurcation.

• 보건의료산업학회지
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• 제6권3호
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• pp.39-52
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• 2012

Main purpose of this study is to provide some managerial suggestions for local small and medium-sized hospitals that are in poorer business environment than large hospitals such as university hospitals, in managing the manpower efficiently, improving business performance and enhancing competitiveness, by empirically investigating the relationship among competency, organizational structure and business performance. Major results are as follows: First, regression analysis for the effects of hospital competency on nonfinancial performance revealed that marketing competency, intangible resource competency and financial resource competency, in that order of importance, had significant influence on nonfinancial performance. Second, regarding the analysis of the effects of hospital competency on financial performance, financial resource competency, marketing competency and intangible resource competency, in that order of importance, significantly affected financial performance. Third, as for the moderating effect, significant result was obtained in an interaction between hospital competency and organizational structure. Financial resource competency had a positive significant impact on nonfinancial performance. However, it had negative significant impact on it by interactive effect with organizational structure.

• 한국멀티미디어학회논문지
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• 제2권1호
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• pp.9-21
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• 1999

이 논문에서는 시간지원 데이터의 시간적 특성을 고려해서 과거 세그먼트, 현재 세그먼트, 그리고 미래 세그먼트로 분리해서 저장하는 과거 현재 미래 저장 구조를 제안하였으며, 과거 현재 미래 저장 구조를 기반으로 하는 데이터 이동 기법 두 가지를 제안하였다. 이 논문에서 제안한 과거 현재-미래 저장 구조에서는 데이터 이동 프로세서가 데이터를 이동하기 위한 시기를 결정하는 방법을 제안하였다. 이 논문에서 제안한 데이터 이동 기법 두 가지 중에서, 시간단위에 의한 이동 기법에서는 각 세그먼트에 저장되는 개체 버전을 정의하였고 데이터의 유효성을 검사하고 이동하는 과정을 보였다. 그리고 LST-GET에 의한 이동 기법에서는LST와GET를 정의하였고 LST와GET를 기준으로 각 세그먼트에 저장되는 개체 버전을 정의하였다. 모의 실험을통해서 기존의 저장 구조와 과거-현재 미래 저장 구조에 대해서 사용자 질의에 대한 성능을 비교하였고, 두 가지 데이터 이동 기법의 성능을 분석하였다.

• 한국항공운항학회지
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• 제22권2호
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• pp.27-33
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• 2014

There are several methods to improve the flight efficiency of HALE(High Altitude Long Endurance) UAV(Unmaned Aerial Vehicle). Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. In order to reduce the weight of airframe structures, new concepts which are different from traditional airframe structure design such as the mylar wing skin should be introduced. The spar is the most important component in a mylar skin wing structure, so the spar weight reduction is the key point for reduction of the wing structural weight. In this study, design trade-off study for the front spar of the HALE UAV wing is conducted in order to reduce the weight. Design and analysis procedure of high aspect ratio wing spar are introduced. Several front spar structures are designed and trade-off study regarding the weight and strength for the each spar are performed. Spar design configurations are verified by the static strength test. Finally, optimal front spar design is decided and applied to the HALE UAV wing design.

• Earthquakes and Structures
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• 제10권4호
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• pp.867-891
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• 2016

This paper addresses numerically the behavior of steel structures under Fire-after-Earthquake (FAE) loading. The study is focused on a four-storey library building and takes into account the damage that is induced in structural members due to earthquake. The basic objective is the assessment of both the fire-behavior and the fire-resistance of the structure in the case where the structure is damaged due to earthquake. The combined FAE scenarios involve two different stages: during the first stage, the structure is subjected to the ground motion record, while in the second stage the fire occurs. Different time-acceleration records are examined, each scaled to multiple levels of the Peak Ground Acceleration (PGA) in order to represent more severe earthquakes with lower probability of occurrence. In order to study in a systematic manner the behavior of the structure for the various FAE scenarios, a two-dimensional beam finite element model is developed, using the non-linear finite element analysis code MSC-MARC. The fire resistance of the structure is determined using rotational limits based on the ductility of structural members that are subjected to fire. These limits are temperature dependent and take into account the level of the structural damage at the end of the earthquake and the effect of geometric initial imperfections of structural members.

• 한국소음진동공학회논문집
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• 제25권6호
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• pp.432-439
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• 2015

In order to reduce the structure borne noise of the equipment sufficiently, its exciting force should be restricted and additional anti-vibration devices such as resilient mount and bellows should be applied. Since the structure borne noise is dependent on the design of the base for the equipment, it is very important to design the base with low vibration. Therefore, in this research, various types of the base design for the shipboard equipment are investigated to reduce the structure borne noise. In order to design the base with low vibration, the exciting force at the center of the gravity of the equipment is firstly defined through the experiment. Using the exciting force identified by experiments, various types of base designs for the typical turbo machine are evaluated by FEM(finite element method) analysis.

• 전기학회논문지
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• 제60권2호
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• pp.446-450
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• 2011

Tunable SC(Switched Capacitor) bandpass ${\Sigma}-{\Delta}$(Sigma-Delta) modulator used in wireless system receiver occurs a signal attenuation according to tuning of center frequency in signal bandwidth. In this paper, tunable bandpass 4th order SC bandpass ${\Sigma}-{\Delta}$ modulator with novel structure is proposed for rejection of signal attenuation in signal bandwidth. The existing structure uses a ten variable coefficient values for rejection of signal reduction in the modulator. But the proposed structure only use a two variable coefficient values for rejection of signal attenuation in the modulator. Also, an adder and comparator is replaced with a comparator having 4 inputs in the modulator. Therefore, the existing structure has one more OP-AMP. The purposed modulator was designed in $0.18\;{\mu}m$ CMOS technology. The resolution of the modulator within 310 kHz bandwidth and 40 MHz sampling frequency under 6.67 MHz, 10 MHz and 13.33 MHz intermediate frequency are over 10 bit.

• 정보관리학회지
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• 제28권1호
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• pp.123-144
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• 2011

본 연구는 학문의 지적 구조를 분석하는 새로운 분석기법인 저자프로파일링분석과 전통적인 분석기법인 저자동시인용분석을 비교하여 분석함으로써 국내 연구환경에 맞는 지적 구조 분석 방법을 제안하는 데 목적을 두고 있다. 이를 위하여 본 연구에서는 인용색인을 이용하지 않고 학문의 지적 구조를 분석할 수 있는 텍스트마이닝을 이용한 저자프로파일링분석을 통하여 새로운 지적 구조 방법의 유용성을 확인하 고자 하였다. 분석대상 학술지는 "대한건축학회 논문집 - 계획계"를 대상으로 하였다.

• 한국수학교육학회지시리즈A:수학교육
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• 제53권1호
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• pp.25-40
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• 2014

Mathematical concept exists in the structural form, not in the independent form. The purpose of this study is to consider the network which students actually have for the mathematical concept structure related to the properties of derivatives. First, we analyzed the properties of derivatives in 'Mathematics II' and showed the mathematical concept structure of the relations among derivatives, functions, and primitive functions as a network. Also, we investigated the understanding of high school students for the mathematical concept structure between derivatives and functions, and the structure between functions and second order derivatives when the functional formula is not given, and only the graph is given. The results showed that students mainly focus on the relation of 'function-derivatives', the thinking process for direction of derivative and the thinking style for algebra. On this basis, we suggest the educational implication that is necessary for students to build the network properly.

• 한국기계가공학회지
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• 제19권12호
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• pp.70-79
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• 2020

This paper describes a comparative study of characteristics of probabilistic design using various reliability analysis methods in the structure design of an automatic salt collector. The thickness sizing variables of the main structural member were considered to be random variables, including the uncertainty of corrosion, which would be an inevitable hazard in the work environment of the automatic salt collector. Probabilistic performance functions were selected from the strength performances of the automatic salt collector structure. First-order reliability method, second-order reliability method, mean value reliability method, and adaptive importance sampling method were applied during the reliability analyses. The probabilistic design performances such as reliability probability and numerical costs based on the reliability analysis methods were compared to the Monte Carlo simulation results. The adaptive importance sampling method showed the most rational results for the probabilistic structure design of the automatic salt collector.