• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.655-666
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• 1995

Advanced Intelligent Network(AIN) and X.500 directory service have similarity in between. X.500 capabilities and the requirements for the Service Control Function(SCF) to Service Data Function(SDF) in AIN. As an interface, SCF can be mapping as a Directory User Agent(DUA) and SDF can be mapping as a Directory System Agent(DSA). Based on the concepts, X.500 directory can be applied to AIN. In this paper we suggest to apply the X.500 DSP to the SDF/SDF interface to perform a distribution function. Also we show that the SCF-SDF/SDF-SDF relationship can be possible under applying X.500 DAP/DSP within the set of Capability Set 1 (CS1),CS2 and CS3. Finally, based on the above contents, we introduce the designed schematic of AIN SDF Server System for a distributed processing in AIN and design the X.500 schema of Universal Personal Telecommunication(UPT) service for supporting AIN SDF Server.

• Journal of IKEEE
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• v.22 no.4
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• pp.1068-1072
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• 2018

In underwater communications, there are many challenges due to energy limitations, long propagation delay, low data rate, and high power loss, unlike terrestrial RF communications. Especially, the propagation delay of underwater acoustic channel is five orders of magnitude higher than in electro-magnetic terrestrial channels due to the low speed of sound(1,500m/s). Thus, the MAC protocols for terrestrial communications are not suitable for underwater network. In this paper, we studied the considerations for MAC protocol in underwater acoustic channel. Here, we concentrated on CSMA based MAC protocols. From the results, we confirmed that the number of control packets has an important effect on the performance in underwater environment. These results would be useful in designing MAC protocols for underwater acoustic communications.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1023-1026
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• 2005

In the ubiquitous computing environment, an intelligent vehicle is defined as a sensor node with a capability of intelligence and communication in a wire and wireless network space. To make it real, a lot of problems should be addressed in the aspect of vehicle mobility, in-vehicle communication, common service platform and the connection of heterogeneous networks to provide a driver with several intelligent information services beyond the time and space. In this paper, we present an intelligent information system for managing in-vehicle sensor network and a vehicle gateway for connecting the external networks. The in-vehicle sensor network connected with several sensor nodes is used to collect sensor data and control the vehicle based on CAN protocol. Each sensor node is equipped with a reusable modular node architecture, which contains a common CAN stack, a message manager and an event handler. The vehicle gateway makes vehicle control and diagnosis from a remote host possible by connecting the in-vehicle sensor network with an external network. Specifically, it gives an access to the external mobile communication network such as CDMA. Some experiments was made to find out how long it takes to communicate between a vehicle's intelligent information system and an external server in the various environment. The results show that the average response time amounts to 776ms at fixed place, 707ms at rural area and 910ms at urban area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.819-824
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• 2015

SDN (Software Defined Network) technology, hardware and network control functions should be separated independently of existing switches or routers and data transfer functions and are also refers to a separate network architecture that can develop and run. When planning a network and designed to reflect the network control function by applying the SDN may reflect the resources efficiently. In this study, one people suggest Applications SDN, which offer an absolutely necessary part of a coded program that combines the benefits of the existing IOS (Combined Benefits) applying the model to complete the Controller part through the MPLS IOS. The OpenFlow Controller is a command to the router LER(Label Edge Router), and transmits the packet in accordance with the command to the destination according to the EXP bit. To configure TCP / IP to the IOS through the optimized coding. Using the OpenFlow protocol controller transmits an encapsulation header as defined in the MPLS packet.

• Journal of Korea Game Society
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• v.2 no.1
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• pp.23-29
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• 2002

Multicast protocols are efficient methods of group communication such as video conference, Internet broadcasting and On-Line Game, but they do not support the various transmission protocol services like a reliability guarantee, FTP, or Telnet that TCPs do. The Purpose or this Paper is to find a method to utilize multicast routers can simultaneously transport multicast packets and TCP packets. For multicast network scalability and error recovery the existing SRM(Scalable Reliable Multicast)method has been used. Three packets per TCP transmission control window site are used for transport and an ACK is used for flow control. A CBR(Constant Bit Rate) and a SRM is used for UDP traffic control. Divided on whether a UDP multicast packet and TCP unicast packet is used simultaneously or only a UDP multicast packet transport is used, the multicast receiver with the longest delay is measured on the number of packets and its data receiving rate. It can be seen that the UDP packet and the TCP's IP packet can be simultaneously used in a server router.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.231-234
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• 2003

The Closed Control System, which uses exclusive network and protocol, have been adopted in TM/TC systems. However, the Closed Control System is known that it is not able to support the integration in the water management automation. There are two methods in integration solution in different types of TM/TC System. One solution is hardware system integration that is very expensive and impractical. The other solution is software system integration that uses OLE for Process Control(OPC). In this study, we recommend OPC solution, for KARICO water management, that is the practical and efficient. KARICO is using OPC technology in MMI(Man machine Interface) and water management program. Through this technology, the real-time status of reservoir, pumping station and canal can be achieved without difficulty.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.420-422
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• 2007

Nowadays, the demand for home networking system is gradually increasing. But most of vendors use their own protocols. KNX/EIB ( European Installation Bus / Konnex) is a standard protocol approved as an European (EN 50090 - EN 13321-1) and a World-wide standard (ISO/IEC 14543). In this study, we develop on/off and dimming lighting control system using BIM. In this system, BIM communicates to micro-controller using PEI(Physical External Interface) communication. And this enables including more KNX/EIB communication objects in lighting control system, and providing lighting control algorithm. The technology in this paper can help to adapt the world-wide standards.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1378-1381
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• 2002

This paper describes a control network which has a new node structure in the LonWorks networks. The proposed node structure is applicable to flexible and more complex applications which are impossible in the conventional Lonworks node structure. We implemented a node in order to evaluate the proposed control networks and verified the commercial feasibility and compatibility by experimenting the implemented node in the conventional Lonworks control networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1417-1422
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• 1991

In this paper we develop an analytic model for end-to-end communication protocols and study the window mechanism for flow control in store-and-forward computer networks. We develop a flow control model in which the parameters of the system are not dynamically adjusted to the stochastic fluctuation of the system load. Simulation results are presented and it is shown that the throughput-delay performance of a network can be improved by proper selection of the design parameter, such as timeout, the number of retransmission, etc.

• Journal of Communications and Networks
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• v.15 no.6
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• pp.606-613
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• 2013

This paper proposes a complete solution of a contention-based medium access control in wireless local networks to provide station level quality of service guarantees in both downstream and upstream directions. The solution, based on the mature distributed coordination function protocol, includes a new fixed contention window backoff scheme, a tuning procedure to derive the optimal parameters, a super mode to mitigate the downstream bottleneck at the access point, and a simple admission control algorithm. The proposed system guarantees that the probability of the delay bound violation is below a predefined threshold. In addition, high channel utilization can be achieved at the same time. The numerical results show that the system has advantages over the traditional binary exponential backoff scheme, including efficiency and easy configuration.