• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2609-2612
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• 2003

This paper describes a 64 channel signal generator/analyzer module that is useful for verification and testing of digital circuits. It can perform logic analyzer function and signal generator function at the same time. The 64 Channel module is implemented with single FPGA chip for miniaturization, and an USB interface is used to increase portability of the module. Multiple modules can be used in parallel for the verification of large scale circuits. Moreover, since the module is implemented as a PC based system, one can configure convenient GUI(Graphic User Interface) environment.

• 전기의세계
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• v.29 no.2
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• pp.111-117
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• 1980

Contacts formed by vacuum evaporation of As-Te-Si-Ge chalcogenide glass onto Al metal (99.9999%) are studied by measuring paralle capacitance C(V), Cp(w), resistance R(V), Rp(w), and I-V characteristics. The fact that contact metal alloying produced high-resistance region is confirmed from the measurements of parallel capacitance and resistance. From the I-V characteristics in the pre-switcing region, it is found that electronic conduction and sitching occurs in the vicinity of metal-amorphous semiconductor interface. From the experimental obsevations, it is concuded that the current flow in the thin film is space-charge limited current (SCLC) due to the tunneling of electrons through the energy barriers.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.71-75
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• 1999

In this paper, we present the 3DOF force-reflecting interface which allows to acquire force of object within a virtual environment. This system is composed of device, virtual environment model, and force-reflecting rendering algorithm. We design a 3 DOF force-reflecting device using the parallel linkage, torque shared by wire, and the controller of system applied by impedance control algorithm. The force-reflecting behaviour implemented as a function position is equivalent to controlling the mechanical impedance felt by the user. Especially how force should be supplied to user, we know using a God-Object algorithm. As we experiment a system implemented by the interface of 3D virtual object and 3DOF force-reflecting interface, we can feel a contact, non-contact of 3D virtual object surface and sensing of push button model.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.635-638
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• 2004

External bonding of steel plates has been used to strengthen deficient reinforced-concrete structures since the 1960s. In recent years, fiber-reinforcde polymer(FRP) plates have been increasingly used to replace steel plates due to their superior properties. This paper is concerned with anchorage failure due to crack propagation parallel to the boned plated near or along the adhesive/concrete interface, staring from the critically stressed position toward the anchored end of the plates. Factor of bond-slip interface model is average bond stress, effective length, slip volume and fracture energy. The aim of the present paper is to provide a comprehensive assessment of bond-slip interface model with concrete and CFRP plates.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.247-249
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• 2007

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60㎐ power-line noise, amplifier, and a level circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.361-368
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• 2010

In this paper, the parallel algorithm using MPI(Message-Passing Interface) library is introduced in order to improve numerical efficiency for the staggered method for nearly incompressible and impermeable porous media which was introduced by Park and Tak(2010). The porous media theory and the staggered method are also briefly introduced in this paper. Moreover, we account for MPI library for blocking, non-blocking, and collective communication, and propose combined the staggered method with the blocking and nonblocking MPI library. And then, we present how to allocate CPUs on the staggered method and the MPI library, which is related with the numerical efficiency in order to solve unknown variables on nearly incompressible and impermeable porous media. Finally, the results comparing serial solution with parallel solution are verified by 2 dimensional saturated porous model according to the number of FEM meshes.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.81-90
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• 2000

Parallel manipulator is suitable for the high precise task because it than has higher stiffness, larger load capacity and more excellent precision, due to the closed-lop structure, than serial manipulator. But the controller design for parallel manipulator is difficult because the parallel manipulator has both the complexity of structure and the interference of actuators. The precision improvement of parallel manipulator using a classical linear control scheme is difficult because the parallel manipulator has the tough nonlinear characteristics. In this paper, firstly, the kinematic analysis of a parallel manipulator used at the experiments is performed so as to show the controllability. The analysis of internal singular configuration of the workspace is performed using the kinematic isotropic index so a sto show the limitation of control performance of a simple linear controller with fixed control gains. Secondly, a control scheme is designed by using an adaptive fuzzy logic controller so that active joints of the parallel manipulator track more precisely the desired input trajectory. This adaptive fuzzy logic controller so that active joints of the parallel manipulator track more precisely the desired input trajectory. This adaptive fuzzy logic controller is often used for the control of nonlinear system because it has both the inference ability and the learning ability. Lastly, the effeciency of designed control scheme is demonstrated by the real-time control experiments with IBM PC interface logic H/W and S/W of my won making. The experimental results was a success.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.149-158
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• 1996

In this paper we describe designing and implementing a digital neural chip and a parallel neural machine for simulating large scale neural netsorks. The chip is a single-chip multiprocessor which has four digiral neural processors (DNP-II) of the same architecture. Each DNP-II has program memory and data memory, and the chip operates in MIMD (multi-instruction, multi-data) parallel processor. The DNP-II has the instruction set tailored to neural computation. Which can be sed to effectively simulate various neural network models including on-chip learning. The DNP-II facilitates four-way data-driven communication supporting the extensibility of parallel systems. The parallel neural machine consists of a host computer, processor boards, a buffer board and an interface board. Each processor board consists of 8*8 array of DNP-II(equivalently 2*2 neural chips). Each processor board acn be built including linear array, 2-D mesh and 2-D torus. This flexibility supports efficiency of mapping from neural network models into parallel strucgure. The neural system accomplishes the performance of maximum 40 GCPS(giga connection per second) with 16 processor boards.

• Journal of computational fluids engineering
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• v.19 no.2
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• pp.24-29
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• 2014

In this study, a parallel performance of CUPID-code has been investigated for both Ethernet and Infiniband network system to examine the effect of cache memory and network-speed. Bi-conjugate gradient solver of CUPID-code has been parallelised by using domain decomposition method and message passing interface (MPI). It is shown that the parallel performance of Ethernet-network system is worse than that of Infiniband-network system due to the slow network-speed and a small cache memory. It is also found that the parallel performance of each system deteriorates for a small problem due to the communication overhead, but the performance of Infiniband-network system is better than Ethernet-network system due to a much faster network-speed. For a large problem, the parallel performance depends less on network system.

• Spatial Information Research
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• v.11 no.3
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• pp.213-226
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• 2003

With the increasing demand of processing massive geographic data, conventional GISs based on the single processor architecture appear to be problematic. Especially, performing complex GIS operations on the massive geographic data is very time consuming and even impossible. This is due to the processor speed development does not keep up with the data volume to be processed. In the field of GIS, this PC clustering is one of the emerging technology for handling massive geographic data effectively. In this study, a MPI(Message Passing Interface)-based parallel processing approach was conducted to implement the existing raster GIS operations that typically requires massive geographic data sets in order to improve the processing capabilities and performance. Specially for this research, four types of raster CIS operations that Tomlin(1990) has introduced for systematic analysis of raster GIS operation. A data decomposition method was designed and implemented for selected raster GIS operations.