• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.411-416
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• 2015

The service size of an IoT environment is determined by the various types of sensors. A gateway for relaying sensor information from various sensors is a representative middleware system, and an infographics showing the information with a graphical presentation of data and information is a client system for representing real-time information efficiently, it is necessary a similar test bed with IoT environment to develop a real-time infographics displaying a large amount of information effectively. The testing tools used in developing the existing network systems are mostly made to be suitable for functional testing and performance testing of the driven unit. In this paper, we proposed a mean which is web-based simulation framework to create a variety of information required for real-time infographics development, and evaluate the function of the system proposed by the test function of the comparison with the previous network test tool.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.9
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• pp.41-49
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• 2008

This paper presents a design of the control block of a passive UHF RFID tag IC according to EPCglobal Class-1 Generation-2 UHF RFID 1.1.0 Protocol. The control block includes a PIE block, CRC5/CRC16, a Slot Counter, a Random Number Generator, a Main Control Block, a Encoder and a Memory Interface. The control block has been designed using the Verilog HDL and has been simulated. Functional simulation results for the overall control block operation show that 11 instructions with 7 states are operated correctly. Also, the control block has been implemented with 36,230 gates by Synopsys Design Compiler and Apollo using Magnachip 0.25$\mu$m technology.

• Journal of IKEEE
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• v.11 no.1 s.20
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• pp.54-60
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• 2007

In this study novel ESD protection device, namely, N/P-type Low Voltage Triggered SCR, has been proposed, for high speed I/O interface. Proposed device could lower high trigger voltage($\sim$20V) of conventional SCR and reduce latch-up phenomenon of protection device during the normal condition. In this Study, the proposed NPLVTSCR has been simulated using TMA MEDICI device simulator for electrical characteristic. Also the proposed device's test pattern was fabricated using 90nm TSMC's CMOS process and was measured electrical characteristic and robustness. In the result, NPLVTSCR has 3.2V $\sim$ 7.5V trigger voltage and 2.3V $\sim$ 3.2V holding voltage by changing PMOS gate length and it has about 2kV, 7.5A HBM ESD robustness(IEC61000-4-2).

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.194-200
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• 2012

In this paper, we proposed a SPICE model of high-voltage insulated gate bipolar transistor(IGBT). The proposed model consists of two sub-devices, a MOSFET and a BJT. Basic I-V characteristics and their temperature dependency were realized by adjusting various parameters of the MOSFET and the BJT. To model nonlinear parasitic capacitances such as a reverse-transfer capacitance, multiple junction diodes, ideal voltage and current amplifiers, a voltage-controlled resistor, and passive devices were added in the model. The accuracy of the proposed model was verified by comparing the simulation results with the experimental results of a 1200V trench gate IGBT.

• Journal of IKEEE
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• v.17 no.1
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• pp.77-82
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• 2013

In this paper, dc-dc buck converter controled by the peak current-mode pulse-width-modulation (PWM) presented. Based on the small-signal model, we propose the novel methods of the power stage and the systematic stability designs. To improve the reliability and performance, over-temperature and over-current protection circuits have been designed in the dc-dc converter systems. To prevent electrostatic An electrostatic discharge (ESD) protection circuit is proposed. The proposed dc-dc converter circuit exhibits low triggering voltage by using the gate-substrate biasing techniques. Throughout the circuit simulation, it confirms that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS (8.2V). The circuit simulation is performed by Mathlab and HSPICE programs utilizing the 0.35um BCD (Bipolar-CMOS-DMOS) process parameters.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.325-330
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• 2006

The container terminal is the unified transportation system which connects between a land transportation and a sea transportation. This system has many subsystems such as ship operation, yard transfer operation, yard storage system, gate operation, and information manage system. This paper presents a method of modeling a simulator with which user can evaluate the efficiency of the equipment and allocation policies in the container terminal. The final purpose is to estimate the efficiency of each equipments and the distribution policies. In a design step in the simulator development. We suggest the Object Oriented method with which the developer can easily design, because the object oriented method has the advantages of reusability and modularity.

• Journal of IKEEE
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• v.25 no.2
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• pp.381-387
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• 2021

As Head-Mounted Displays(HMDs), which are mainly used to maximize realism in games and videos, have experienced increased demand and expanded scope of use in education and training, there is growing interest in methods to enhance the performance of conventional HMDs. In this study, a methodology to utilize Carbon NanoTubes(CNTs) to improve the performance of gate drivers that send control signals to each pixel circuit of the HMD is discussed. This paper proposes a new circuit design method that replaces the transistors constituting the buffer part of the conventional gate driver with transistors incorporating CNTs and compare the performance of the suggested gate drive with that of a gate driver comprising only conventional transistors via simulations. According to the simulation results, by including CNTs in the gate driver, the output voltage can be increased by approximately 0.3V compared to the conventional gate driver high voltage(1.1V) at a speed of 12.5 GHz and the gate width also can be reduced by up to 20 times.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.13-18
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• 2017

The purpose of this study was to investigate CTDI (computed tomography dose index at center) for various phantom shapes, sizes, and compositions by using GATE (geant4 application for tomographic emission) simulations. GATE simulations were performed for various phantom shapes (cylinder, elliptical, and hexagonal prism PMMA phantoms) and phantom compositions (water, PMMA, polyethylene, polyoxymethylene) with various diameters (1-50 cm) at various kVp and mAs levels. The $CTDI_{100center}$ values of cylinder, elliptical, and hexagonal prism phantom at 120 kVp, 200 mAs resulted in 11.1, 13.4, and 12.2 mGy, respectively. The volume is the same, but $CTDI_{100center}$ values are different depending on the type of phantom. The water, PMMA, and polyoxymethylene phantom $CTDI_{100center}$ values were relatively low as the material density increased. However, in the case of Polyethylene, the $CTDI_{100center}$ value was higher than that of PMMA at diameters exceeding 15 cm ($CTDI_{100center}$ : 35.0 mGy). And a diameter greater than 30 cm ($CTDI_{100center}$ : 17.7 mGy) showed more $CTDI_{100center}$ than Water. We have used limited phantoms to evaluate CT doses. In this study, $CTDI_{100center}$ values were estimated and simulated by GATE simulation according to the material and shape of the phantom. CT dosimetry can be estimated more accurately by using various materials and phantom shapes close to human body.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.809-819
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• 2000

This paper deals with an optimal capacity allocation problem and performance analysis in Advanced Information Communication Processing System(AICPS). AICPS is a gateway system interconnection PSTN(Public Switched Telephone Network), ISDN(Intergrated Services Digital Network), PSDN(Packet Switched Data Network), internet, Frame Relay and ATM together. This study considers not only ISDN and Internet but also user behavior of On-line service which is analyzed by Markov process. A call blocking probability of TNAS and INAS is computed by Erlang's formula. Then, PNAS and WNAS's call blocking probability are computed by Stochastic knapsack modeling. The result is compared with result of simulation. Finally, we allocate an optimal capacity minimizing total call blocking probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2C
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• pp.123-130
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• 2002

To cope with the Internet host mobility in a cellular network environment, we propose an adaptive mobility management scheme that can compensate drawbacks of Mobile IP. We also propose protocol that supports the proposed scheme. Our proposed scheme determines foreign agent care-of addresses adaptively according to user mobility. Consequently, it is different from other proposals for micro mobility, which statically assign the gateway in the domain as a foreign agent. Using such a scheme, it is possible to effectively meet the users demands for different service qualities in the various environments considered in the cellular network and to reduce signaling overhead due to frequent handovers occurred in Mobile IP. The performance of the proposed scheme is examined by simulation. The results of simulation show that the proposed scheme can provide relatively stable points of attachment to the mobile node.