• Journal of Korea Society of Industrial Information Systems
• /
• v.20 no.1
• /
• pp.27-35
• /
• 2015

In this paper, we suggested a RS485 based CSMA/CD protocol that is available in low speed multi-node networks such as industry control communication network and home network etc. The suggested protocol was compared to widely used Master-Slave protocol, Modbus. We modeled realistic control network and showed that the average delay and throughput performance were significantly improved in the different transmission rates.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.7 no.3
• /
• pp.137-141
• /
• 2014

RFID system is applied to various industry such as process control, distribution management, access control, environment sensing, entity identification, etc. Since RFID system uses wireless communication, it has more weak points for security. In this paper, an authentication protocol is suggested between tags and a reader, which is basic property for security. A suggested protocol use a bivariate polynomial over a finite field and is secure against snooping, replay attack, position tracking and traffic analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.7
• /
• pp.1737-1753
• /
• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• Journal of information and communication convergence engineering
• /
• v.15 no.1
• /
• pp.28-36
• /
• 2017

The medium access control (MAC) protocol based on dynamic time division multiple access/time division duplex (TDMA/TDD) is responsible for random access control and radio resource allocation in dynamic traffic environments. These functions of random access and resource allocation are very important to prevent wastage of resources and improve MAC performance according to various network conditions. In this paper, we propose new random access and resource allocation schemes to guarantee quality of service (QoS) and provide priority services in a dynamic TDMA/TDD system. First, for the QoS guarantee, we propose an adaptive random access and resource allocation scheme by introducing an access probability. Second, for providing priority service, we propose a priority-based random access and resource allocation scheme by extending the first adaptive scheme in both a centralized and a distributed manner. The analysis and simulation results show that the proposed MAC protocol outperforms the legacy MAC protocol using a simple binary exponential backoff algorithm, and provides good differential performance according to priorities with respect to the throughput and delay.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1558-1562
• /
• 2005

This paper describes the design and implementation of a wireless home network system using Home Network Control Protocol (HNCP) called the wireless HNCP home network system. For wireless interfaces of HNCP, IEEE 802.11b and IEEE 802.15.4 standard protocols are considered. With the implementation of the wireless HNCP home network system, a simple analysis about coexistence between IEEE 802.11b and IEEE 802.15.4 is achieved. Through the implemented wireless HNCP home network system and the analytical results about the coexistence between both two different wireless protocols, the feasibility of the wireless HNCP home network system is shown.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.10
• /
• pp.10-20
• /
• 1994

This paper presents a CATV SMS (Status Monitoring System) using HDLC (High Level Data Link Contorl) protocol and the system implementation.The system specifications were derived from the analysis of technical status and requirement of the domestic CATV industry. For the interoperability with a global network management system in the future, HDLC protocol was adopted in the system. The system performance was improved by using the communication controller chip and the large data buffer. For reducting the communication problems induced by accumulated noise in up-stream data channels, the system was designed that the different communication channel can be assigned to each proper mass of terminal. The operating software was designed with menu driven user interface and have various functions for the convenience of users. The test result of the implemented system at the experimental network showed good performance and suitability for a coaxial CATV Status Monitoring System.

• International Commerce and Information Review
• /
• v.11 no.1
• /
• pp.379-403
• /
• 2009

The Purpose of this study is to research the problems of trade restriction for an environment protection. Environmental regulation relate to trade are Convention on International Trade in Endangered Species of Wild Fauna & Flora, Montreal Protocol on Substances that Deplete the Ozone Layer, Kyoto Protocol to the UN Framework Convention on Climate Change, Basel Convention on the Control of Transboundary Movements of Hazardous Wastes & Their Disposal, Cartagena Protocol on Biosafty and WTO Agreement. Regulatory action for environmental protection has economics instrument, command & control, liablity, damage compensation, voluntary agreement. In the case of our country, impact of regulatory action for environmental protection is low. Because is recognized position of developing country yet. For in the balance rules of trade and enviroment, First must satisfy WTO's basic principles and principle of quantitative restrictions prohibition, Second, operation of protection action must reasonable and objective standards Third, must satisfy GATT article 20 (b) clause and (g) protestation each essential factor To grow for environment advanced country, we should do i) using of FTA ii) international cooperation strengthening for developing country position iii) construction of environment information network

• Proceedings of the IEEK Conference
• /
• 2009.05a
• /
• pp.3-5
• /
• 2009

In this paper, we exploit the cooperative diversity relay protocol to compensate for defects of wireless communication in 60 GHz. We derive and proof results of the numerical expressions versus various scenarios using the computer simulations. Optimal location and scaling factor of relay are presented through analysis of performances and compared between direct-path and time diversity transmission. Consequently, our results confirm that cooperative diversity relay protocol is an effective mean of enhancing the performance of wireless communication systems in 60 GHz.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.05a
• /
• pp.1656-1660
• /
• 2006

Distributed coordination function(DCF) is the primary random access mechanism of IEEE 802.11, which is the basic protocol of wireless LAN based on the CSMA/CA protocol. It enables fast installation with minimal management and maintenance costs and is a very robust protocol for the best effort service in wireless medium. The current DCF, however, is known to be unsuitable for real-time applications such as voice message transmission. In this paper, we focus on the performance issues of IEEE 802.11 which accommodate the prioritized messages. Existing results use the initial window size and backoff window-increasing factor as tools to handle the priority of the messages. Instead, we introduce a novel scheme which chooses the backoff timer with arbitrary probabilities. By this, one can greatly reduce the backoff delay of the lower priority messages without degrading the performance of higher priority.

• International Journal of Internet, Broadcasting and Communication
• /
• v.10 no.1
• /
• pp.11-15
• /
• 2018

The application of Wireless Sensor Networks requires a wise utilization of limited energy resources. Therefore, a wide range of routing protocols with a motivation to prolong the lifetime of a network has been proposed in recent years. Hierarchical clustering based protocols have become an object of a large number of studies that aim to efficiently utilize the limited energy of network components. In this paper, the effect of mismatch in parameter estimation is discussed to evaluate the robustness of a distanced based algorithm called distributed clustering protocol in homogeneous and heterogeneous environment. For quantitative analysis, performance simulations for this protocol are carried out in terms of the network lifetime which is the main criteria of efficiency for the energy limited system.