• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1941-1951
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• 1998

In this paper, hardware circuit that performs functions of IEEE 802.11 wireless LAN frequency hopping PLCP protocol is designed using 0.8 um CMOS cmn8a technology of the COMPASS. Transmission rate of the designed hardware is 1Mbps. The designed circuit have about 6300 gates and $2.5{\times}2.5mm^2$ area. In order to verify the circuit, two PLCP circuits are interconnected and frames are transmitted from one PLCP circuit to the other PLCP circuit. As a results of the simulation, we conclude that the designed PLCP circuit works well as the IEEE 802.11 standard specification.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.48-55
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• 2005

In this paper, a mathematical model and a simulation method for the response time analysis of Local Interconnect Network(LIN) based network systems are proposed. Network-induced delays in a network based control system can vary widely according to the transmission time of message and the overhead time of transmission. Therefore, in order to design a distributed control system using LIN network, a method to predict and verify the timing behavior of LIN protocol is required at the network design phase. Furthermore, a simulation environment based on a timing model of LIN protocol is beneficial to predict the timing behavior of LIN. The model equation is formulated with six timing parameters deduced from timing properties of LIN specification. Additionally, LIN conformance test equations to verify LIN device driver are derived with timing constraints of the parameters. The proposed model equation and simulation method are validated with a result that is measured at real LIN based network system.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.197-206
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• 2003

With the growing usage of the networks, the world-wide Internet has become the main means to exchange data and carry out transactions. It has also become the main means to attack hosts. To solve the security problems which occur in the network such as Internet, we import software products of network security elements like an IDS (Intrusion Detection System) and a firewall. In this paper, we have designed and constructed the General Simulation Environment of Network Security model composed of multiple IDSes and a firewall which coordinate by CNP (Contract Net Protocol) for the effective detection of the intrusion. The CNP, the methodology for efficient integration of computer systems on heterogeneous environment such as distributed systems, is essentially a collection of agents, which cooperate to resolve a problem. Command console in the CNP is a manager who controls tie execution of agents or a contractee, who performs intrusion detection. In the Network Security model, each model of simulation environment is hierarchically designed by DEVS (Discrete EVent system Specification) formalism. The purpose of this simulation is to evaluate the characteristics and performance of CNP architecture with rete pattern matching algorithm and the application of rete pattern matching algorithm for the speeding up the inference cycle phases of the intrusion detection expert system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.1049-1062
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• 2019

The national accredited certificate is a user certificate issued based on the user's personal information, which has been identified in advance, and has become a universal authentication method used for most electronic financial transactions and user authentication. And it contributed a lot to the use of e-government and domestic service. However, due to the lack of web standards on how to use, it was inconvenient to install a separate plug-in, and efforts to improve it have been continued. In this paper, we attempt to solve the problem of certificate usage environment by presenting the certificate digital signature method using the extension of the FIDO2 (Fast Identity Online v2) client to authentication protocol (CTAP) specification.

• ETRI Journal
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• v.44 no.3
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• pp.450-461
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• 2022

The Gen-Z protocol is a memory semantic protocol between the memory and CPU used in computer architectures with large memory pools. This study presents the implementation of the Gen-Z hardware system configured using Gen-Z specification 1.0 and reports its performance. A hardware prototype of a DDR4 Gen-Z memory pool with an optimized character, a block device driver, and a file system for the Gen-Z hardware was designed. The Gen-Z IP was targeted to the FPGA, and a 512 GB Gen-Z memory pool was configured on an ×86 server. In the experiments, the latency and throughput of the Gen-Z memory were measured and compared with those of the local memory, SATA SSD, and NVMe using character or block device interfaces. The Gen-Z hardware exhibited superior throughput and latency performance compared with SATA SSD and NVMe at block sizes under 4 kB. The MySQL and File IO benchmark of Gen-Z showed good write performance in all block sizes and threads. Besides, it showed low latency in RocksDB's fillseq dbbench using the ext4 direct access filesystem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.811-815
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• 2005

IPSec(Internet Protocol Security) is a framework for a set of protocols for security at the network or packet processing layer of network communication. IPSec is providing authentication, integrity and confidentiality security services. The specifications for Internet Key Exchange(IKEv1) were released to the world. Some criticisms of IKEv1 were that it was too complex and endeavored to define too much functionality in one place. Multiple options for multiple scenarios were built into the specification. The problem is that some of the included scenarios are rarely if ever encountered. For IPsec to work, the sending and receiving devices must chare a Public Key. This is accomplished through a protocol known as Internet Security Association and Key Management Protocol/Oakley(ISAKMP/Oakley), which allows the receiver to obtain a public key and authenticate the sender using digital certificates. This thesis is a study on the performance improvement of the security transmission using the SSFNet(Scalable Simulation Framework Network Models)

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.239-248
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• 2002

International Standard Organizations such as ITU(International Telecommunication Union) and IETF (Internet Engineering Task Force) are proceeding standardization for various applications and protocols to provide video-conference and multimedia conference services on a variety of networks. Remote device control among these protocols is provided with various capabilities as well as device control to multimedia conference. This protocol for remote device control is standardizing as H.282 recommendation which is specified as core service for the configuration and control of remote device to multimedia conference. The H.282 recommendation does not specify the use of a particular transport protocol. That is, T.120 multimedia conference uses T.136 and H.323 video conference uses H.283 for the transport of H.282 protocol. The introduced system in this paper is based on H.282 and is implemented to be capable of remote device control within the framework of H.323 using H.283. Also, it is shown that a variety of services in the specification of the standard are satisfied through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1465-1470
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• 2011

In this paper, we propose a new MAC protocol, namely DM-MMAC (Doze Mode Multi-Channel MAC) for ad hoe wireless networks which can utilize multiple channels effectively, thereby enhancing the network throughput considerably. Basically, the IEEE 802.11 specification allows for the use of multiple channels available at the physical layer, but its MAC protocol is designed only for a single channel with the fatal drawback, so called multi-channel hidden terminal problem in multi-channel environments. In this vein, several multi-channel MAC protocols have been proposed, but most of them demonstrate the performance problem that its throughput drastically decreases as the number of mobile hosts residing in a given network increases with small number of available channels. In this work, we tried to improve the performance of multi-channel MAC protocols in terms of network throughput as well as power saving effects by simplifying the channel assignment and channel capturing procedures and reducing the possibility of collisions between mobile hosts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.241-249
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• 1997

In this paper, a new technique is proposed for generating a minimum-length synchronizable test sequence that can be applied in the distributed test architecture where both external synchtonization and input/output operation costs are taken into consideration. the method defines a set of transformation rules that constructs a duplex digraph from a given finite state machine representation of a protocol specification rules that constructs a duplex digraph from a given finite state machine representation of a protocol specificatio such that a rural chinese postman tour of the duplex digraph can be used to generate a minimum-length synchronizable test sequence using synchronizable distinguishing sequences as the state identification sequence for each state of the given finite state machine. The method provides an elegant solution to the synchronization problem that arises during the application of a predetermined test sequence in some protocol test architectures that utilize remote testers.