• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.43-52
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• 2016

Wireless sensor network (WSN) technology has been implemented using commercial off-the-shelf microcontrollers (MCUs), In this paper, we propose a simulation environment to realize the physical evaluation of FPGA-based node by considering vertically cross-layered WSN in terms of physical node device and network interconnection perspective. The proposed simulation framework emulates the physical FPGA-based sensor nodes to interoperate with the NS3 through the runtime infrastructure (RTI). For the emulation and interoperation of FPGA-based nodes, we extend a vendor-providing FPGA design tool from the host computer and a script to execute the interoperation procedures. The standalone NS-3 is also revised to perform interoperation through the RTI. To resolve the different time-advance mechanisms between the FPGA emulation and event-driven NS3 simulation, the pre-simulation technique is applied to the proposed environment. The proposed environment is applied to IEEE 802.15.4-based low-rate, wireless personal area network communication.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.584-596
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• 2013

WSN (Wireless Sensor Network), to take advantage of the range was gradually expanded. So WSN access from public network to the desire to be increased. As a result, the test network environment for research has been progressing steadily. Because it requires a lot of sensor nodes, to establish of Testbed for WSN is difficult. in this paper suggests efficient integration test simulation environment of Testbed and Virtual environment for WSN. In addition to this paper suggests simulation environment able to integration of simulation time of Testbed and NS-3.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.193-194
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• 2017

본 논문에서는 VANET 환경에서 SUMO와 ns-3를 이용하여 속도 변화에 따라 AODV 프로토콜의 통신에 대해 모의실험을 수행하였다. 해당 시뮬레이션 결과에 따르면, AODV 라우팅 프로토콜은 VANET 환경에서 차량이 일정 속도 이상 빨라지게 되면 통신율이 급격히 하락함을 볼 수 있었다.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.61-68
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• 2015

Mobile ad hoc networks (MANETs) are self-organized dynamic networks populated by mobile nodes. This paper presents the improved cross-layer approach to complement the recent works for video transmission services on MANET. We use a statistical design of experiment and analysis in order to investigate interactions between major factors of each layer effectively with minimizing ns-3 simulation run time. The proposed cross-layer approach considers MANET protocol layers (i.e., physical, network and transmission layers) and an application layer (i.e., a video encoder) as factors simultaneously. In addition, the approach defines an objective video quality metric as a response variable. The result of this paper can be applicable as a preliminary research to design an optimized video transmission application which has ability to adjust controllable factors to dynamic uncontrollable factors.

• Journal of IKEEE
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• v.20 no.3
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• pp.295-298
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• 2016

In this paper, we analysed the properties of the conventional ESD protection devices such as SCR, MVSCR, LVTSCR. The electrical characteristics and the turn-on time properties are simulated by Synopsys T-CAD simulator. As the results, the devices have the holding voltages between 2V and 3V, and the trigger voltage of about 20V with SCR, of about 12V with MVSCR, of about 9V with LVTSCR. The results of the simulation for the turn-on time properties are 2.8ns of SCR, 2.2ns of MVSCR, 2.0ns of LVTSCR. Thus, we prove that LVTSCR has the shortest turn-on time. However, the second breakdown currents(It2) of the devices are 7.7A of SCR, 5.5A of MVSCR, 4A of LVTSCR. This different properties have to be adapted by the operation voltages for I/O Clamps.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.1-6
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• 2010

Simulation analysis may be the essential means to either evaluate performance of systems or optimize system parameters for new design. Including many variations for design and implementation, MANET (Mobile Ad-hoc NETwork) is one target area of such an analysis. Since every node, however, included in the network has mobility, one MANET could be overlapped or merged with another one which use a different transport protocol. In order to communicate among nodes in this case, the new merged network should configure paths and addresses in advance. Configuring paths and addresses generates much overheads which ultimately cause delay in communicating data. Performance analysis is required to improve the data transport performance by minimizing overheads. This paper proposes a sound address auto-configuration method which is based on an on-demand manner and then presents modeling and performance analysis of the method. NS-2 simulation results verify that the proposed method can not only alleviate overheads, which are inevitably generated for address auto-configuration processes, and but also decentralize them in time.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.1
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• pp.88-97
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• 2000

We have proposed and analysed a novel Lookup Algorithm which had a short switching speed and tiny memory size for IP router. This algorithm could simply be implemeted by a hardware with SRAM because of simple structure. This Lookup scheme needs 1${\sim}$3 memory access times. When we simulated with 40,000 routing record obtained from IPMA Website, the maximum memory size of this algorithm was 316KB(the offset threshold for compression algorithm was 8). When we simulated by HDL using ALTERA EPM7256 series and 100MHz clock and SRAM of 10ns access time, the total lookup time was 45ns for two memory access, 175ns for three memory access.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.216-222
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• 2004

Frequency selective fading is a limiting factor for transmission rate and performance in high-speed multimedia communications. In this paper, we propose a turbo coded adaptive quadrature amplitude modulation (QAM) system for efficient high-speed transmission. By making use of a user-friendly simulation platform of SPW, the proposed turbo coded adaptive QAM system(TuAQAM) is developed and its performance is evaluated in terms of throughput and BER performance. Two channel models having delay spreads of 700ns and 1400ns are created for the simulations. It is shown that the proposed TuAQAM system provides a performance improvement of approximately 3dB and improved throughput for the channel model whose delay spread is 700ns. Similarly, a performance improvement is also achieved for the channel model whose delay spread is 1400ns.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.363-366
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• 2001

LILI-128 스트림 암호는 IMT-2000 무선단말간 데이터 암호화를 위하여 제안된 128-비트 크기의 스트림 암호방식이며, 클럭 조절형태의 채택에 따라 속도저하라는 구조적인 문제점을 안고 있다. 본 논문에서는 귀환/이동에 있어서 랜덤한 4개의 연결 경로를 갖는 4-비트병렬 $LFSR_{d}$를 제안함으로서 속도문제를 해결하였다. 그리고 ALTERA 사의 FPGA 소자(EPF10K20RC240-3)를 선정하여 그래픽/VHDL 하드웨어 구현 및 타이밍 시뮬레이션을 실시하였으며, 50MHz 시스템 클럭에서 안정적인 50Mbps (즉, 45 Mbps 수준인 T3급 이상, 설계회로의 최대 지연 시간이 20ns 이하인 조건) 출력 수열이 발생될 수 있음을 확인하였다. 마지막으로, FPGA/VHDL 설계회로를 Lucent ASIC 소자 ($LV160C,\;0.13{\mu}m\;CMOS\;&\;1.5v\;technology$)로 설계 변환 및 타이밍 시뮬레이션한 결과 최대 지연시간이 1.8ns 이하였고, 500 Mbps 이상의 고속화가 가능함을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.215-217
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• 2014

본 논문에서는 ns-3 기반의 IEEE 802.15.4 모의 성능 평가에 대해 기술한다. IT 기술의 발달과 함께 차세대 전력망인 '스마트 그리드'가 대두되고 있다. 이에 따라 무선 센서들 간의 통신을 위해 IEEE 802.15.4 표준 기술이 채택되고 있다. IEEE 802.15.4 표준에는 beacon-enabled mode 와 non beacon-enabled mode 두 가지 채널 접근 기법이 존재하지만 특정 기법의 용도와 목적에 대해서는 구체적으로 명시되지 않는다. 따라서 본 논문에서는 스마트 그리드 환경에서 IEEE 802.15.4 의 두 채널 접근 기법의 성능을 시험하고 beacon-enabled mode 와 non beacon-enabled mode 간의 성능 분석을 통해 beacon-enabled mode 의 효용성에 대하여 연구한다.