• Journal of KIISE
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• v.43 no.2
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• pp.256-268
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• 2016

Modern networks consisting of various heterogeneous equipment are often installed in a distributed manner. Thus the NETCONF standard was established to manage networks centrally and efficiently. In this paper, we present a method that integrates each NETCONF layer into a single system based on the results of previous studies. In the RPC Layer, an asynchronous communication channel and parallel processes are possible using multi-threading. In the Operation Layer, operational efficiency is increased by using a data group with dependencies between the equipment configuration data and by improving the data structure, enabling efficiently processing of XML queries even with multiple managers. The data modeling techniques and grouping methods in the Content Layer are presented in detail for interoperability between the Operation Layer and the Content Layer. Finally, the GUI program was implemented and its implementation is reported. We performed an experiment comparing the improved NETCONF with the standard NETCONF to measure factors, such as query processing ratio, query processing speed, and CPU utilization. The improved NETCONF demonstrated excellent query processing ratio and query processing speed, whereas the standard NETCONF had excellent CPU utilization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5140-5147
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• 2013

This paper presents a new idea of structural design of the optical access network for IPOW(IP over WDM) services. More efficient network can be constructed, because the IP packets are transmitted directly to the WDM without going through an intermediate layer of networks. The wavelength Routing is based on a label switching technology. The ability to transmission of high volume traffics and QoS capability of the optical label switching directly to the end user of the IPOW optical internet networks is provided. As in AON(Active Optical Network) flexible bandwidth on demand subscribers is allocated. By the Simulation of the proposed optical access networks to measure the BER(Bits Error Ratio) at the end of the nodes the network characteristics are analyzed. These results are based on the design of efficient optical network.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2344-2346
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• 2002

A vacuum control system has been developed for using Ethernet Multi Serial Device Severs (EMSDS) for the Pohang Accelerator Laboratory (PAL) storage ring. There are 124 vacuum ion pumps at the storage ring. It was a very important problem to solve the problem how to control such a big number of vacuum pumps distributed around the ring. After discussions, we decided to develop a serial to ethernet interrace device sever that will be mounted in the control system rack. It has a 32-bits microprocessor embedded Linux, 12 ports RS485 (or RS232) slave interface. one channel 10/100BaseTx ethernet host port, one channel UART host port, and 16 Mbytes large memory buffer. These vacuum pumps are connected to Ion-Pump serial controllers, which chop the AC current so as to control the current in the pumps. The EMSDS connect either 100BaseTx or 10BaseT ethernet networks to asynchronous serial ports for communication with serial device. It can simultaneously control up to 12 ion-pump serial controllers. 12 EMSDS are connected to a personal computer (PC) through the network. The PC can automatically control the EMSDS by sending a set of commands through the TCP/IP network. Upon receiving a command from a PC running under Windows2000 through the network, the EMSDS communicate through the stave serial interrace ports to ion-pump controller. We added some software components on the top of EPICS (Experimental Physics and Industrial Control System) toolkit.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.826-834
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• 2002

Asynchronous third generation mobile communication system is able to service Packet Switching through adding GPRS Network to the second generation system GSM. Therefore, it is necessary to study packet traffic service of GGSN node which is due to perform gateway role that GPRS Network is enable to inter-connect with Internet in order to optimize the capability and performance of GGSN. In this paper, the Internet packet traffic model that it is arrived to GGSN node from the Internet is studied and In order to process the Inter traffic efficiently, performance analysis model in GGSN is proposed to optimize packet processing capability of each processor. In order to guarantee QoS requirement of the real time traffic Speech and Video, several scheduling algorithm is applied to performance model and each mechanism is compared with several performance parameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.34-44
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• 2003

As the recent rapid development of internet technology and the wide spread of multimedia communications, massive increase of network traffic causes some problems such as the lack of network paths and the bad quality of service To resolve these problems, this paper presents a web-based traffic control system which supports QoS of realtime packet transmission for the multimedia communication The traffic control system presented in this paper applies the integrated service model and provides QoS of packet transmission by means of determining the packet transmission rate according to the policies of network manager and the optimal resource allocation considering the end-to-end traffic load It also provides QoS for the realtime packet transmission through the admission controller and the packet scheduler by the modified $WF^2Q^+$ algorithm support asynchronous and class-based queuing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.472-486
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• 2000

This paper analysis the performance of joint receiving structure consisting of the decorrelating multiuser detection and beamfromenr-RAKE receive for DS-CDMA communication systems. In asynchronous transmission as the number of simultaneous users increase. the capacity of CDMA system becomes severly reduced due to the nonideal orthogonality between user-assigned PN sequences and improper power control. Accordingly, the CDMA receiving system becomes vulnerable to the multiple access interferences and the near-far problem under multipath fading channel environment. To withstand these undesired performance degradations, this paper proposes the new type of multiuser detection which has a form of the hybrid structure of concatenating beamformer-RAKE receiver and decorrelating multiuser detection. the beam former-RAKE receiver performs temporal and spatial diversity combining with alleviating fading effect and suppressing undesired interferences, and the multiuser detection plays a role of making the receiver robust to the near-far problem. Regarding the individual merit on the usage of either multiuser detection or beamformer-RAKE receiver, the hybrid one is expected to produce the enhanced performance in multipath fading CDMA channel. However major drawback of using decorrelating multiuser detection for practical deployment is arised from its computational complexity , which is exponentially increased as more number of users and transmitted symbols involve. To diminish the computational complexity, this paper exploits an efficient block Toeplitz inversion technique using matrix Levinson polynomial will be introduced. And this paper provided the mathematical analysis to show the efficiency of the proposed joint structure under the multipath propagation environment. And results of a series of exhaustive computer simulations are presented in order to demonstrate the overall performance of the proposed hybrid structure in multipath fading CDMA channel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.703-717
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• 2002

This paper illustrates the implementation of a scalable shared buffer asynchronous transfer mode (ATM) switch. The designed shared buffer ATM switch has a shared buffet of a pipelined memory which has the access time of 4 ns. The high-speed buffer access time supports a possibility of the implementation of a shared buffer ATM switch which has a large switching capacity. The designed switch architecture provides flexible switching performance and port size scalability with the independence of queue address control from buffer memory control. The switch size and the buffer size of the designed ATM switch can be reconfigured without serious circuit redesign. The designed prototype chip has a shared buffer of 128-cell and 4 ${\times}$ 4 switch size. It is integrated in 0.6um, double-metal, and single-poly CMOS technology. It has 80MHz operating frequency and supports 640Mbps per port.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1531-1539
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• 2017

The existing SSD storage tester processed logs in a 1-N structure between server and client using TCP and network file system. This method causes some problems for example, an increase in CPU usage and difficulty in exception handling, etc. In this paper, we implement a log processing message layer that can deal with asynchronous distributed processing using open source messaging system such as kafka, RabbitMQ and compare this layer with existing log transmission method. A log simulator was implemented to compare the transmission bandwidth and CPU usage. Test results show that the transmission using the message layer has higher performance than the transmission using the message layer, and the CPU usage does not show any significant difference The message layer can be implemented more easily than the conventional method and the efficiency is higher than that of the conventional method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.384-389
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• 2005

The objective on this project is to develop a cooperative Field Robot (FR), by using a customize Open Control Platform (OCP) as design and development process. An OCP is a CORBA-based solution for networked control system, which facilitates the transitioning of control designs to embedded targets. In order to achieve the cooperation surveillance system, two FRs are distributed by navigation messages (GPS and sensor data) using CORBA event-channel communication, while graphical information from IR night vision camera is distributed using CORBA Asynchronous Method Invocation (AMI). The QoS features of AMI in the network are to provide the additional delivery method for distributing an IR camera Images will be evaluate in this experiment. In this paper also presents an empirical performance evaluation from the variable chunk sizes were compared with the number of clients and message latency, some of the measurement data's are summarized in the following paragraph. In the AMI buffers size measurement, when the chuck sizes were change, the message latency is significantly change according to it frame size. The smaller frame size between 256 bytes to 512 bytes is more efficient fur the message size below 2Mbytes, but it average performance in the large of message size a bigger frame size is more efficient. For the several destination, the same experiment using 512 bytes to 2 Mbytes frame with 2 to 5 destinations are presented. For the message size bigger than 2Mbytes, the AMI are still able to meet requirement far more than 5 clients simultaneously.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.139-149
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• 2007

Asynchronous OFCDM(Orthogonal Frequency and Code Division Multiplexing) systems must have a cell search process necessarily unlike synch개nous systems. this process is hewn initial synchronization and a three-step cell search algorithm is performed for the initial synchronization in the following three steps: OFCDM symbol timing, i.e., Fast Fourier Transform(FFT) window timing is estimated employing guard interval (GI) correlation in the first step, then the frame timing and CSSC(Cell Specific Scrambling Code) group is detected by taking the correlation of the CPICH(Common Pilot Channel) based on the property yielded by shifting the CSSC phase in the frequency domain. Finally, the CSSC phase within the group is identified in the third step. This paper proposes a modification group code with two or three block of the conventional CPICH based cell search algorithm in the second step which offers MS(Mobile Station) complexity reductions. however, the effect of the reduction complexity leads to degradation of the performance therefore, look for combination to have the most minimum degradation. the proposed block type group code with suitable combinations is the nearly sane performance as conventional group code and has a complexity reduction that is to be compared and verified through the computer simulation.