• Journal of KIISE:Information Networking
• /
• v.32 no.2
• /
• pp.254-260
• /
• 2005

In the guaranteed service, a real-time scheduling algorithm must achieve both high level of network utilization and scalable implementation. Here, network utilization indicates the number of admitted real-time sessions. Unfortunately, existing scheduling algorithms either are lack of scalable implementation or can achieve low network utilization. For example, scheduling algorithms based on time-stamps have the problem of O(log N) scheduling complexity where N is the number of sessions. On the contrary, round-robin algorithms require O(1) complexity. but can achieve just a low level of network utilization. In this paper, we propose a scheduling algorithm that can achieve high network utilization without losing scalability. The proposed algorithm is a Hierarchical Round-Robin (H-RR) algorithm that utilizes multiple rounds with different interval sizes. It provides latency bounds similar to those by Packet-by-Packet Generalized Processor Sharing (PGPS) algorithm using a sorted-Priority queue. However, H-RR requires a constant time for implementation.

• Proceedings of the IEEK Conference
• /
• 2000.06c
• /
• pp.121-124
• /
• 2000

Goal of this Paper is to design and develop core kernel components f3r single processor real-time system, which include real-time schedulers, synchronization mechanism, IPC, message passing, and clock & timer. The goal also contains the basic researches on dynamic load balancing and scheduling which provide mechanism for the distributed information processing and efficient resource sharing among various information appliances based on network.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.40.1-40
• /
• 2001

In this paper, control theoretic approaches are proposed to guarantee QoS (Quality of Series) such as packet delay and packet loss of real-time traffic in high-speed communication network. Characteristics of variable rate real-time traÆc in communication networks are described. The mathematical model describing networks including source and destination nodes are suggested. By a traffic control mechanism, it is shown that worst-case end-to-end transfer delay of traffic can be controlled and packet loss can be prevented. The simulation shows results of delay control and buer level control to raise QoS in realtime traffic.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.9
• /
• pp.97-104
• /
• 2015

Recently, the need for real-time systems which are providing various types of information that occur in large quantities in IoT environment is increasing. In this paper, we propose a middleware system which can monitor in real time on a web environment. The proposed system is designed to be integrated by using communication functions provided by a network operating system and external sensors. The proposed system is compared with an existing system and analysed by the server performance testing tool.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.8B
• /
• pp.699-706
• /
• 2003

This paper is to verify that 2-state MMPP Model conform to ATM VBR traffic characteristics by measuring and analyzing real-time VBR traffic in KT's ATM network. As a result, we validated the fact that real-time VBR traffic of ATM network cannot be apply to MMPP model and must be represented by previously general On-Off Model with characteristics as follows: arrival rate of On state (λ$_1$) is deterministic, arrival rate of Off state (λ$_2$) is zero, and two transition rate (T$_1$,T$_2$) is only random variable. As research results are to handle real traffic, these results can be used to all ATM network traffic model with traffic management function such as KT's ATM network.

• Structural Engineering and Mechanics
• /
• v.16 no.6
• /
• pp.643-654
• /
• 2003

Two real-time modeling prediction (RMP) schemes are presented in this paper for analyzing the behavior of deep excavations during construction. The first RMP scheme is developed from the traditional AR(p) model. The second is based on the simplified Elman-style recurrent neural networks. An on-line learning algorithm is introduced to describe the dynamic behavior of deep excavations. As a case study, in-situ measurements of an excavation were recorded and the measured data were used to verify the reliability of the two schemes. They proved to be both effective and convenient for predicting the behavior of deep excavations during construction. It is shown through the case study that the RMP scheme based on the neural network is more accurate than that based on the traditional AR(p) model.

• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.13-16
• /
• 2000

Recently, with the advent of satellite communication technologies, the network access service through satellites has emerged as an alternative to existing ones. Of satellite access services including multimedia services, the high speed internet access service will be one of the important services. Particularly, the efficient transportation of real time internet traffic seems very essential. The aim of this research is to examine the applicability of the IETF RTP protocol in the satellite access network. The RTP has been developed for the QoS-met transportation protocol of real time traffic over the existing best-effort internet. This paper summarizes the RTP protocol, and describes the architecture of the implementation of the RTP. And also, the compressed RTP header protocol is discussed for the applicability to the satellite link.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.393-398
• /
• 2002

Neural networks are used in the framework of sensorbased tracking control of robot manipulators. They learn by practice movements the relationship between PSD (an analog Position Sensitive Detector) sensor readings for target positions and the joint commands to reach them. Using this configuration, the system can track or follow a moving or stationary object in real time. forthermore, an efficient neural network architecture has been developed for real time learning. This network uses multiple sets of simple backpropagation networks one of which is selected according to which division (corresponding to a cluster of the self-organizing feature map) in data space the current input data belongs to. This lends itself to a very training and processing implementation required for real time control.

• Proceedings of the Korean Information Science Society Conference
• /
• 2008.06d
• /
• pp.476-479
• /
• 2008

Wireless Sensor Network typically incorporates various real time applications that must meet timing constraints under severe resource limitations. Due to the high data rate and burst traffic for that type of applications, occurrence of congestion is very common. Ensuring the end-to-end deadline under congested scenario is quite challenging. In this paper we propose a hop-by-hop rate control algorithm which avoids the congestion as well as ensures that the real time traffic will meet the end-to-end deadline by guaranteeing the meeting of local deadline at intermediate hop. Finally, simulation has demonstrated the effectiveness of our approach.

• Proceedings of the KWS Conference
• /
• 2000.04a
• /
• pp.303-306
• /
• 2000

Quality estimation of the weld has been one of the important issues in RSW which is a main process of the sheep metal fabrication in auto-body industry, It was well known that among the various welding process variables, dynamic resistance has a close relation with nugget formation. With this variable, it is possible to estimate the weld quality in real time. In this study, a new quality estimation algorithm is developed with the primary dynamic resistance measured at welding machine timer. For this, feature recognition method of Hopfield neural network is used. Primary resistance patterns are vectorized and classified with five patterns. The network trained by these patterns recognizes the dynamic resistance pattern and estimates the weld quality Because the process variable monitored at the primary circuit is used, it is possible to apply this system to real time application without any consideration of electrode wear or shunt effect.