• 한국광학회지
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• 제23권5호
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• pp.227-232
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• 2012

본 논문에서는 RLD (Reflective Laser Diode)와 FBG (Fiber Bragg Grating)가 하이브리드 집적된 LD (이하 FG-LD)의 정적 및 동적 특성을 해석하기 위하여 대신호 시영역 모델링 방법을 구현하였다. FBG의 유효길이 2.1 mm를 포함한 외부 집적 공진기의 길이가 8 m인 경우에 0.44GHz의 동적 주파수 요동과 6.4 GHz 정도의 동적 주파수 요동 결과를 나타내었다. 또한 10 Gbps NRZ 신호의 아이가 크게 오픈된 상태를 잘 유지함을 확인하였다. FG-LD는 50 km 정도의 길이를 커버하는 10 Gbps 급 단일파장 레이저로서의 효용성이 있을 것으로 기대된다.

• 소성∙가공
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• 제23권4호
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• pp.231-237
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• 2014

In the current study, a rate-dependent crystal plasticity finite element method (CPFEM) was used to simulate flow stress behavior and texture evolution of a body-centered cubic (BCC) crystalline material during plastic deformation at room temperature. To account for crystallographic slip and rotation, a rate-dependent crystal constitutive law with a hardening model was incorporated into an in-house finite element program, CAMPform3D. Microstructural heterogeneity and anisotropy were handled by assigning a crystallographic orientation to each integration point of the element and determining the stiffness matrix of the individual crystal. Uniaxial tensile tests of single crystals with different crystallographic orientations were simulated to determine the material parameters in the hardening model. The texture evolution during four different deformation modes - uniaxial tension, uniaxial compression, channel die compression, and simple shear deformation - was investigated based on the comparison with experimental data available in the literature.

• 상하수도학회지
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• 제26권4호
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• pp.565-578
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• 2012

Integrated watershed sewage works program(IWSWP) is defined as implementing, by one of local governments or central government, sewage facilities planning, installation and management for a certain watershed in which criteria of water quality is established and two or more local governments are involved. It is shown that IWSWP is more efficient for the improvement of water quality of water body than conventional local sewage works program(CLSWP) and besides, economical benefits can be achieved by integration of facilities and M&O. In this research, case study for 8 watershed area were investigated to evaluate the difference of effect between IWSWP and CLSWP. The research shows that IWSWP has the money saving result of approximately 12 % by cost reduction for sewage works investment. B/C analysis result shows that B/C ratio of IWSWP was 1.749 and it is higher than B/C ratio of 1.439 for CLSWP. At the same time, the B/C sensitivity analysis is carried out for the rate of discount and the recreational use benefit.

• Structural Engineering and Mechanics
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• 제64권4호
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• pp.515-526
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• 2017

Dynamic response of functionally graded Carbon nanotubes (FG-CNT) reinforced pipes conveying viscous fluid under accelerated moving load is presented. The mixture rule is used for obtaining the material properties of nano-composite pipe. The radial force induced by viscous fluid is calculated by Navier-Stokes equation. The material properties of pipe are considered temperature-dependent. The structure is simulated by Reddy higher-order shear deformation shell theory and the corresponding motion equations are derived by Hamilton's principal. Differential quadrature (DQ) method and the Integral Quadrature (IQ) are applied for analogizing the motion equations and then the Newmark time integration scheme is used for obtaining the dynamic response of structure. The effects of different parameters such as boundary conditions, geometrical parameters, velocity and acceleration of moving load, CNT volume percent and distribution type are shown on the dynamic response of pipe. Results indicate that increasing CNTs leads to decrease in transient deflection of structure. In accelerated motion of the moving load, the maximum displacement is occurred later with respect to decelerated motion of moving load.

• Journal of Power Electronics
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• 제11권4호
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• pp.439-448
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• 2011

In this work the Multi-Domain model of an electric vehicle is developed. The electric domain model consists on the traction drive and allows including faults associated with stator winding. The thermal model is based on a spatial discretization. It receives the power dissipated in the electric domain, it interacts with the environment and provides the temperature distribution in the induction motor. The mechanical model is a half vehicle model. Given that all models are obtained using the same approach (Bond Graph) their integration becomes straightforward. This complete model allows simulating the whole system dynamics and the analysis of electrical/mechanical/thermal interaction. First, experimental results are aimed to validate the proposed model. Then, simulation results illustrate the interaction between the different domains and highlight the capability of including faults.

• 센서학회지
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• 제26권4호
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• pp.223-227
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• 2017

Conventional CMOS image sensors (CISs) have a trade-off relationship between dynamic range and sensitivity. In addition, their sensitivity is determined by the photodiode capacitance. In this paper, CISs that consist of dual-sensitivity photodiodes in a unit pixel are proposed for achieving wide dynamic ranges. In the proposed CIS, signal charges are generated in the dual photodiodes during integration, and these generated signal charges are accumulated in the floating-diffusion node. The signal charges generated in the high-sensitivity photodiodes are transferred to the input of the comparator through an additional source follower, and the signal voltages converted by the source follower are compared with a reference voltage in the comparator. The output voltage of the comparator determines which photodiode is selected. Therefore, the proposed CIS composed of dual-sensitivity photodiodes extends the dynamic range according to the intensity of light. A $94{\times}150$ pixel array image sensor was designed using a conventional $0.18{\mu}m$ CMOS process and its performance was simulated.

• 천문학논총
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• 제22권4호
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• pp.169-175
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• 2007

The international cooperation project CIBER (Cosmic Infrared Background ExpeRiment) is a rocket-borne instrument, of which the scientific goal is to measure the cosmic near-infrared extra-galactic background to search for signatures of primordial galaxy formation. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. Currently, all the subsystems have been built, and the integration, testing, and calibration of the CIBER system are on process for the scheduled launch in June 2008.

• 한국농촌건축학회논문집
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• 제10권4호
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• pp.33-40
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• 2008

This paper aims to clarify the spatial form and functional transition of Korean traditional shop house in Maehwa marketplace, Uljin. The general form of Korean traditional shop house of Maehwa marketplace was the timbered house of the tin roof built in the 1960s. As the scale of a building being comparatively small-scale, building area is $60m^2$ and the yard was mainly made behind the building. When the spatial form of Korean traditional shop house is considered, the composition of 4 by 2 is most. And in the front of a building, the shop is located, and when the back of a building prepares a residence, integration of a sales function and a habitation function is seen. The shop of Korean traditional shop house is converted into living space by change of the function, and the position is the middle of a front of building. This is considered as what inherited the Korean lifestyle. And the last, Although it is not different from the appearance of the shop house of other areas, since there are few grades of the change in comparison, the extension situation of Korean traditional shop house is recognized as an example important for future research.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.288-292
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• 2013

In this paper, a carbon implant is investigated in detail from the perspectives of performance advantages and side effects for the thick n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET). Threshold voltage ($V_{th}$) adjustment using a carbon implant significantly improves the $V_{th}$ mismatch performance in a thick (3.3-V) n-MOS transistor. It has been reported that a bad mismatch occurs particularly in the case of 0.11-${\mu}m$ $V_{th}$ node technology. This paper investigates a carbon implant process as a promising candidate for the optimal $V_{th}$ roll-off curve. The carbon implant makes the $V_{th}$ roll-off curve perfectly flat, which is explained in detail. Further, the mechanism of hot carrier injection lifetime degradation by the carbon implant is investigated, and new process integration involving the addition of a nitrogen implant in the lightly doped drain process is offered as its solution. This paper presents the critical side effects, such as Isub increases and device performance shifts caused by the carbon implant and suggests an efficient method to avoid these issues.

• Structural Engineering and Mechanics
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• 제42권4호
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• pp.471-488
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• 2012

An efficient one dimensional finite element model has been presented for the dynamic analysis of composite laminated beams, using the efficient layerwise zigzag theory. To meet the convergence requirements for the weak integral formulation, cubic Hermite interpolation is used for the transverse displacement ($w_0$), and linear interpolation is used for the axial displacement ($u_0$) and shear rotation (${\psi}_0$). Each node of an element has four degrees of freedom. The expressions of variationally consistent inertia, stiffness matrices and the load vector are derived in closed form using exact integration. The formulation is validated by comparing the results with the 2D-FE results for composite symmetric and sandwich beams with various end conditions. The employed finite element model is free of shear locking. The present zigzag finite element results for natural frequencies, mode shapes of cantilever and clamped-clamped beams are obtained with a one-dimensional finite element codes developed in MATLAB. These 1D-FE results for cantilever and clamped beams are compared with the 2D-FE results obtained using ABAQUS to show the accuracy of the developed MATLAB code, for zigzag theory for these boundary conditions. This comparison establishes the accuracy of zigzag finite element analysis for dynamic response under given boundary conditions.