• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1173-1181
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• 2005

The cooling effect of a mobile phone using PCM(Phase Change Material) module has been numerically investigated. A transient three-dimensional numerical analysis of heat and fluid flow with natural convection is performed in this study. Governing conservation equations for mass, momentum and energy are solved by an implicit finite volume method. An enthalpy-porosity technique has been used for modeling of the melting process. Two different ways of placing the PCM module are considered. One is to place a PCM module between the substrate and battery pack, and the other is to place a PCM module between MCM(multichip module) and battery pack. Three different types of PCMs are used to predict the performance of PCM. The results show that passive cooling with PCM can reduce the temperature rise and the effect of natural convection in PCM module considered in this study is negligible.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.4
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• pp.91-103
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• 2009

A cryptographic module (CM) is an implementation of various cryptographic algorithms and functions by means of hardware or software, When a CM is validated or certified under the CM validation program(CMVP), a finite state model(FSM) of the CM should be developed and provided, However, guides or methods of modeling and analysis of a FSM is not well-known, because the guide is occasionally regarded as a proprietary know-how by developers as well as verifiers of the CM. In this paper, we propose a set of guides on modeling and analysis of a FSM, which is needed for validation of a CM under CMVP, and a transition test path generation algorithm, as well as implement a simple modeling tool (CM-Statecharter). A FSM of a CM is modeled by using the Statechart of UML 2.0, Statechart, overcoming weakness of a FSM, is a formal and easy specification model for finite state modeling of a CM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2605-2619
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• 1996

In this paper, we evaluated performance of mobile exchange control part. Queueing network model is used for modeling of mobile exchange control part. We developed a call control processing and location registration scenartio which has a message exchange function between processors in mobile exchange control part. A network symbol are used the simulation models that are composed of the initialization module, message generation module, message routing module, message processing module, message generation module, HIPC network processing module, output analysis module. as a result of computer simulation, we obtain the processor utilization, the mean queue length, the mean waiting time of control part based on call processing and location registration capacity. The call processing and location registration capacity is referred by thenumber of call attempts in the mobile exchange and must be satisfied with the quality of service(delay time).

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.460-466
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• 2008

In this study, a computer modeling work has been performed for the power generation system using polymer electrolyte fuel cell with Aspen Plus general purpose chemical process simulator. Stoichiometric reactor module was used for the modeling of reformer for the production of hydrogen. For the modeling of the electrochemical reaction, Gibbs reactor module built-in Aspen Plus was utilized. SRK equation of state model was selected for the proper simulation of the overall fuel cell system.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.114-117
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• 2009

The performance of PV module applying the photovoltaic effects of the semiconductor is affected by temperature. Until now, most of PV module show that the power and efficiency falls at a rate of ${\sim}0.5%/^{\circ}C$ and ${\sim}0.05%/^{\circ}C$ respectively as increase of ambient temperature. In this study, the effect of fins attached to the backside of PV module was investigated through a thermal analysis program and simulation model. The result shows that the inner temperature of PV module with fin falls about $10^{\circ}C$ compare to that of ordinary PV module.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.103-110
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• 2010

This paper presents the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method and approximation modeling method with Radial Basis Function (RBF) neural network structure. The complex tool holder is used for holding a (milling/drilling) tool of a machine tool. The engineering problem of complex tool holder results from the twisting of spindle of tool holder. For this purpose, we present the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method (specifically a module of $iSight^{(R)}$ FD-3.1) and approximation modeling method with Radial Basis Function (RBF) (another module of $iSight^{(R)}$ FD-3.1) neural network structure

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.175-180
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• 1990

Rotational-free-surface (RFS) is a special type of free surface whose two boundaries coincide. For NC machining of PFS, a rotational axis as well as three Cartesian axes are required. In this paper, we develop a four-axis CAM module consisting of: a) Geometric modeling of RFS, b) CL-data generation, and c) Graphic simulation of machining operation. To test the validity and effectiveness of the developed module, several test cuts are made with Bridgeport CNC milling machine and compared with the graphic simulation.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1266-1271
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• 2009

Formwork layout is perceived as important due to its strong tie to site works. But, most formwork is done manually and influenced by worker's skill and thus, a lot of construction errors occur. The introduction of BIM (Building Information Modeling) enables acquiring more precise information on the building shape, dimension, structure, etc. than 2D-based drawings and thus, the increased productivity, such as reduction of workload and work times, and the economic efficiency, such as reduction of formwork types and form dimensions with the consideration of constructability, are expected. This study reviewed the previous studies and formwork layout systems to derive this study's differentiations and factors to be first considered for formwork planning were derived by analyzing priorities against consideration factors. Last, a flow chart and algorithm were developed to apply the derived factors to the formwork layout module.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.234-239
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• 2000

In this paper, we developed an automated program for the modeling and manufacturing of three-dimensional roller gear cams. A computer program employing the theory of gearing and coordinate transformation is developed for synthesizing and animating cam mechanisms. A method using wire frame modeling and shading by triangular element is presented, and effectively used for modeling of example with reduced computation time. Then a module for generation NC program a five-axis CNC machine to manufacture roller gear cam is established.

• Journal of the Optical Society of Korea
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• v.19 no.5
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• pp.521-530
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• 2015

Active optics is a key technology for future large-aperture space telescopes. In the design of deformable mirrors for space applications, the design parameter trade-off between the number of regularly configured actuators and the correction capability is essential but rarely analyzed, due to the lack of design legacy. This paper presents a parametric module method for integrated modeling of deformable mirrors with regularly configured actuators. A full design parameter space is explored to evaluate the correction capability and the mass of deformable mirrors, using an autoconstructed finite-element parametric modeling method that utilizes manual finite-element meshing for complex structures. These results are used to provide design guidelines for deformable mirrors. The integrated modeling method presented here can be used for future applied optics projects.