• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.3-10
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• 1997

Meshless particle method is a numerical technique which does not use the concept of element. This method can easily handle special engineering problems which cause difficulty in the use of finite element method, however it has a drawback that essential boundary condition is not satisfied. In this paper, several studies for satisfying essential boundary conditions and enhancing the accuracy of solutions are discussed. Particular emphasis is placed on a new numerical technique in which finite elements are used on the boundaries to satisfy the essential boundary conditions and meshless particle method is used in the interior domain. For coupling of the two methods interface elements are introduced into the zone between the subdomains using meshless particle method and finite element method. The shape functions and the approximated displacement functions of the interface element are derived with the ramp function based on the shape function of finite elements. The whole numerical procedures are formulated by Galerkin method. Several numerical examples for enhancing the accuracy of solution in the meshless particle method and a new coupling method are presented.

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.102-105
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• 2003

A new and simple calibration technique that greatly enhances the measurement sensitivity of conventional fiber-optic reflectometry based on Fresnel reflection from the tip of a fiber is used for demonstrating the feasibility of measuring solute concentrations and index changes in fluids to very high precision. The amplitude of pulses originating from reflection from the fiber-fluid interface is compared in real-time with the amplitude of reference pulses from a fiber-air interface such that errors caused by pulse amplitude fluctuations and slightly varying detector responses are corrected. Using solutions of salt and water, it is demonstrated that the technique is capable of measuring index changes of about $1 {\times} 10^{-5}$ corresponding to a salt concentrations of 0.01 %.

• Journal of the Korean GEO-environmental Society
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• v.19 no.3
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• pp.25-33
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• 2018

Piping is one of the most frequently occurring collapse type of a levee, and is often caused by roofing (backward erosion piping) at the ground-structure interface. Roofing is generally evaluated using creep ratio. However, creep ratio does not take into account the characteristics of the ground-structure interface. In this study, the roofing risk was investigated by using model test and numerical analysis considering the ground-structure interface characteristics. In the model test, it was confirmed that the piping potential decreased as the interface roughness increased, and this was applied to the numerical analysis. Existing numerical methods can not adequately simulate the particle behavior at the ground-structure interface because only the water level difference is considered. In this paper, particle behavior at the interface was investigated by performing seepage analysis and then, carrying out particle analysis technique simulating the boundary condition of the ground-structure interface. Analysis results have shown that the roofing resistance decreases as the ground-structure interface roughness decreases.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.823-830
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• 2001

The single fiber pull-out technique has been commonly used to characterize the mechanical behavior of fiber/matrix interface in fiber reinforced composite materials. In this study, an improved analysis considering the effect of thermal residual stresses in both radial and axial directions is developed for the single fiber pull-out test. It is found to have the pronounced effects on the stress transfer properties across the interface and the interfacial debonding behavior.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.608-612
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• 1990

The robot system which can handle a stream of randomly positioned parts on a conveyor belt system, is developed. It is composed of a PUMA 560 robot, a conveyor belt system and a vision system. The performance of the overall system is mainly dependent upon the robot and vision system interface technique. A vision algorithm is developed to determine the position, orientation and type of the part. Calibration procedure and the vision-to-robot transformation are also proposed. Experimental results are then presented and discussed.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.706-711
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• 2003

A numerical method is presented for computing unsteady incompressible two-phase flows with immersed solids. The method is based on a level set technique for capturing the phase interface, which is modified to satisfy a contact angle condition at the solid-fluid interface as well as to achieve mass conservation during the whole calculation procedure. The modified level set method is applied for numerical simulation of bubble deformation in a micro channel with a cylindrical solid block and liquid jet from a micro nozzle.

• Journal of the Ergonomics Society of Korea
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• v.6 no.2
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• pp.29-37
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• 1987

This paper discusses the gereral principles to be considered in the design of usef interfaces of graphics packages and presents a top-down design process in systematic way. The effective and convenient user interfaces are analyzed based on human factors criteria and we discuss the properties and application requirements of typical interaction techniques which support primitive tasks. The choice of an interaction technique has a set of input device prerequisites to be met.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.16 no.28
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• pp.69-75
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• 1993

The evaluation of product may be classified by technical tests or by ergonomics assessments. If an ergonomics assessment is required, then the three types of interface dimension are available to the researcher. In this paper, we proposed the heuristic evaluation method for usability of product in the three types of interface dimension The evaluation method is used the fuzzy weighted checklist technique computerized for evaluating or comparing prototype of system and IT product.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.180-185
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• 2000

In this paper, a local remeshing technique assisted by flexible user-interface capabilities is presented for precise forging simulation. The rigid-plastic finite element formulation is introduced and the detailed approach to the new local remeshing technique is given. A piercing process in cold forging is simulated by the presented technique and the simulated results are compared with those obtained by the technique and the simulated results are compared with those obtained by the conventional approach and experiments. A typical application example is also given, which emphasizes the capability of the local remeshing technique in forging simulation.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.155-158
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• 2005

An invesitigation on power consumption of a mobile multimedia system using OFDM and MDVS technique is reported here. Analysis and simulation are performed to find the significances of proposed Microscopic Dynamic Voltage Scaling(MDVS) tehnique[4] on digital processor in terms of power saving. A study is also made to show power reduction in mobile multimedia system by incorporating OFDM modulation scheme in RF front-end. Finally, overall power consumption by functionally distinguished blocks ie. RF front-end, digital processor and human interface unit is shown here. Total power consumption is 8.2W for 2Mbps SD-quality WCDMA multimedia video service - the power consumption of digital processor is 3.9W(48%), the power consumption of RF front-end is 3.2W (36%), and the power consumption of interface is 1.8W(16%). Power saving of applying purposed MDVS technique is 35% in digital processor, and power saving of OFDM technique is 10-12dB in RF front-end.