• 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 Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.456-458
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• 2019

In this paper, transmission performance of streaming audio as a railway communication service based on LTE-R is analyzed. Performance analysis is perfomed with computer simulation based on NS(Network Simulation)-3, audio frame of MPEG(Moving Picture Experts Group)-4 is used as target application service for straming audio traffic. Results of this paper can be used to implement LTE-R networks and develope application services over LTE-R network.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.27-34
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• 2006

In this paper, a recently proposed parallel hybrid particle-continuum (DSMC-NS) scheme employing 3D unstructured grid for solving steady-state gas flows involving continuum and rarefied regions is described [1]. Substitution of a density-based NS solver to a pressure-based one that greatly enhances the capability of the proposed hybrid scheme and several practical experiences of implementation learned from the development and verifications are highlighted. At the end, we present some simulation results of a realistic RCS nozzle plume, which is considered very challenging using either a continuum or particle solver alone, to demonstrate the capability of the proposed hybrid DSMC-NS method.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.529-538
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• 2007

In this paper, we have analyzed a simulation model of Slammer worm propagation process which caused serious disruptions on the Internet in the year of 2003 by using NS-2. Previously we had presented and analyzed Abstract Network to Abstract Network(AN-AN) model being modified from the Detailed Network to Abstract Network(DN-AN) of NS-2. However, packet analysis in AN-AN model had a problem of taking 240 hours to simulate the initial 300 seconds of infection. We have reduced the AN-AN model to save the simulation time and analyzed total 3.5 hours of the network congestions within 107 hours. Moreover, we have derived optimal quarantine rate of 0.0022 considering service outage of network devices caused by the heavy infected traffics, which was not taken into consideration in previous works. As the result of simulation, Although the inbound traffic at the Korean international gateway was back in normal conditions at 4,787 second, due to the revese direction saturation was maintained until 12,600 seconds, the service outage was persisted for 3.5 hours.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.568-570
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• 2018

Currently, with rapid progress and supply of mobile communication technology, LTE(Long Term Evolution) technology is expanded and widely used to industrial and emergency communications beyond earlier smart-phone based service. In this paper, transmission performance of voice traffic, one of railway communication service based on LTE-R as an application field of LTE technology, is analyzed. This study is performed performance analysis with level of application service and consider effects of satisfaction level for users. Computer Simulation based on ns(Network Simulation)-3 is used for analysis and VoIP(Voice over Internet Protocol) specification is used for voice traffics. Results of this paper is used to implement LTE-R networks and develope application services over LTE-R network.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.3
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• pp.425-432
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• 2019

Modeling and Simulation(M&S) has widely been used in various areas such as industry, academy and military. Especially, military have used the technology for acquisition, training, and combat assessment. In this paper, we introduce our experience using M&S technique to analyze the network traffic amount and packet delay time between two military bases. For this, we modeled the current network configuration of the military bases and simulated the model with NS-3 tool. The result provided us for an insight regarding the required network performance between two bases.

• 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 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.