• Journal of Internet Computing and Services
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• v.15 no.3
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• pp.53-62
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• 2014

DTN is the next generation network that is used in not guaranteed end-to-end connection such as communication between planet and satellite, frequent connection severance, and not enough for qualified network infrastructure. In this paper, we propose the hybrid Spray-and-Wait algorithm to predict the node contact time by monitoring the periodic contacts information between the nodes. Based on this method, we select one node on the basis of prediction time and copy a message for spray and wait algorithm. In order to verify the the hybrid Spray and Wait algorithm, we use the ONE(Opportunistic Network Environment) Simulator of Helsinki University. The delivery probability of the proposed algorithm is compared to the Binary Spray and Wait algorithm, it is showed that it has 10% less overhead than Binary Spray and Wait routing. It has also shown that it reduces unnecessary copying of this message.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.112-118
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• 2023

As technology advances, the need for enhanced preparedness against cyber-attacks becomes an increasingly critical problem. Therefore, it is imperative to consider various circumstances and to prepare for cyber-attack strategic technology. This paper proposes a method to solve network security problems by applying reinforcement learning to cyber-security. In general, traditional static cyber-security methods have difficulty effectively responding to modern dynamic attack patterns. To address this, we implement cyber-attack scenarios such as 'Tiny Alpha' and 'Small Alpha' and evaluate the performance of various reinforcement learning methods using Network Attack Simulator, which is a cyber-attack simulation environment based on the gymnasium (formerly Open AI gym) interface. In addition, we experimented with different RL algorithms such as value-based methods (Q-Learning, Deep-Q-Network, and Double Deep-Q-Network) and policy-based methods (Actor-Critic). As a result, we observed that value-based methods with discrete action spaces consistently outperformed policy-based methods with continuous action spaces, demonstrating a performance difference ranging from a minimum of 20.9% to a maximum of 53.2%. This result shows that the scheme not only suggests opportunities for enhancing cybersecurity strategies, but also indicates potential applications in cyber-security education and system validation across a large number of domains such as military, government, and corporate sectors.

• Journal of Korea Multimedia Society
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• v.16 no.3
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• pp.354-365
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• 2013

Node deployment is one of the important problems in achieving good quality of service in wireless sensor network. The purpose of this paper is to develop an interactive system that supports user's decision makings in designing sensor fields. The system provides grid-based initial deployment algorithm supporting three types of node deployment pattern, area-fill, path-cover, and barrier-cover deployment pattern. After initial deployment, an iterative refinement algorithm can be applied, which takes care of the irregularity of the deployment area and the heterogeneity of sensors. The proposed system helps users to effectively deploy nodes in the sensor field, analyse the detection performance of the deployment, and perform network simulations. The developed system can be utilized as a part of the development environment of the surveillance sensor network system.

• Journal of Communications and Networks
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• v.5 no.3
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• pp.202-214
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• 2003

The central challenge in the design of ad-hoc networks is the development of dynamic routing protocol that efficiently finds route between mobile nodes. Several routing protocols such as DSR, AODV and DSDV have been proposed in the literature to facilitate communication in such dynamically changing network topology. In this paper, a Node Transition Probability (NTP) based routing algorithm, which determines stable routes using the received power from all other neighboring nodes is proposed. NTP based routing algorithm is designed and implemented using Global Mobile Simulator (GloMoSim), a scalable network simulator. The performance of this routing algorithm is studied for various mobility models and throughput, control overhead, average end-to-end delay, and percentage of packet dropped are compared with the existing routing protocols. This algorithm shows acceptable performance under all mobility conditions. The results show that this algorithm maximizes the bandwidth utilization during heavy traffic with lesser overhead.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.49-54
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• 2019

Since the underwater communication environment, which is used mainly in acoustic channel, is different from terestrial communication, it needs to analyze the appropriate transmission performance in underwater environment to implement the communication services. Appropriate traffic process method for a communication service is required through transmission performance of object traffic for the communication service. In this paper, transmission performance of video traffic on underwater MANET(Mobile Ad-hoc Network) is analyzed and video traffic configuration scheme on underwater MANET with results of performance analysis is suggested, This study is done with computer simulation based on NS(Network Simulator)-3. throughput, transmission delay, packet loss rate is used for transmission performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.225-230
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• 2015

This study presents a method for generating IEC 61850 Sampled Values(SV) traffic by combining the emulation function of network simulator ns-3 with the actual communication equipment. For the SV traffic generation and reception, the emulation function of the network simulator ns-3 is used, while as a communication network, the actual communication equipment, switches are used. In addition, the SV traffic frames generated are analyzed, using Wireshark, and it is confirmed that the SV traffic frames are generated accurately. The method for the SV traffic generation proposed in the present study will be very useful when various SV traffics are generated under the environment of an actual substation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.207-211
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• 2019

Research and development are underway to connect the network to all things in the world and to manage the objects through the Internet. The Internet of Things is expected to play an important role in building ecosystem of next generation mobile communication service. The most significant communication technology is LPWAN. In this paper, we analyze the performance according to each data transmission rate to reduce and manage resource waste by using many LPWAN nodes more efficiently in accordance with the demands of the times. The LPWAN communication technology used in this paper was designed based on LoRaWAN, a long-distance low-power wireless platform developed by Semtech, and analyzed by implementing a virtual IoT base using Network Simulator-3.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.28-34
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• 2006

An ACC driving simulator is a virtual reality device which designed to test or evaluate vehicle control algorithm. It is designed and built based on the rapid control prototyping(RCP) concept. Therefore this simulator adopt RCP tools to solve the equation of a vehicle dynamics model and control algorithm in real time, rendering engine to provide real-time visual representation of vehicle behavior and CAN communication to reduce networking load. It can provide also many different driving test environment and driving scenarios.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.41-48
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• 2011

Wireless communication technology developed, portable wireless devices based on wireless network including the smartphone rapidly developed, and products with functions similar to highly efficient computer are being launched. Therefore, active studies to enable performance of works, which were previously held in computers, on portable wireless terminal are being held. Until now, simulation was undertaken using computers which satisfy high performance computing resource. Such contains a problem that it cannot break away the limit of space. Portable wireless terminal has the merit that it can break away from the limit of space by using wireless network in comparison to wired environment. In this paper, it suggests a simulator based on wireless devices for distributed simulation. For such purpose, the performance time of simulation will be compared in regards to the case of performing nodes control simulation in a single highly efficient computer and the case of performing distributed simulation in many wired and wireless network environments. Through the comparison, the possibility for utility of portable wireless terminal as the object of distributed simulation will be verified, and it will be presented that simulation can be performed in a shorter time by performing distributed simulation under various wired and wireless network environments away from the limit of space.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.3
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• pp.275-280
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• 2010

In this paper, VoIP(Voice over Internet Protocol) transmission performance for MANET(Mobile Ad-hoc Networks) is improved and analyzed with packet aggregation scheme which is aggregating some of short length packets to one large packet and sending to networks. VoIP simulator based on NS(Network Simulator)-2 is implemented and used to measure performance of VoIP traffic transmission. In this simulation, VoIP traffics are generated with parameters of some codes such as G.711, G.729A, GSM.AMR and iBLC. MOS(Mean Opinion Score), end-to-end network delay, packet loss rate and transmission bandwidth are measured. Performance improvements of 98% for MOS, 6.4times for end-to-end network delay, 32times for packet loss rate is shown as simulation results. On the other hand, transmission bandwidth is increased about maximum 10%. Finally, VoIP implementation guide for the performance with packet aggregation is suggested.