• The Transactions of the Korea Information Processing Society
• /
• v.6 no.2
• /
• pp.367-376
• /
• 1999

A variable bit-rate based video services have much limitation for bandwidth management, since its trarfic has a some variances in frame level. In particular, the bandwidth management for video which has characteristics of VBR traffic such a MPEG video could be more complicated. Also, it is difficult to manage the bandwidth effectively for proving a VCR function from VOD service, since we don't know the traffic variance exactly at that time. In this paper, we proposed the dynamic bandwidth allocation a scheme based on VBR traffic based stored video such as MPEG for interactive video service. This scheme can maximize the given total bandwidth through the prefetch based variable length bandwidth allocation scheme and dynamic bandwidth management scheme for multiple streams. Also, our scheme can be used for a MPEG-based bandwidth allocation scheme, and provides the method that can maximize the utilization of network resource for multiple stream by using a dynamic bandwidth management.

• Journal of the Korean Statistical Society
• /
• v.20 no.1
• /
• pp.29-43
• /
• 1991

Two data-based bandwidth selectors which are optimal in the sense that they achieve n$\^$-$\frac{1}{2}$/ rate of convergence in kernel density estimation are proposed. The proposed bandwidth selectors are constructed by modifying Park and Marron's plug-in method. The first modification is taking Taylor expansion of the mean integrated squared error to two more terms than in the case of plug-in method. The second is estimating more accurately the functionals of the unknown density appeared in the minimizer of the expansion by using higher order kernels. The proposed bandwidth selectors were proved to be optimal in terms of convergence rate. According to small-sample Monte Carlo studies, the proposed bandwidth selectors showed better performance than all the other bandwidth selectors considered in the simulation.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.52-55
• /
• 2004

Digital communication networks have become a core technology in advanced building automation systems. BACnet(${\underline{B}}uilding$ ${\underline{A}}utomation$ and ${\underline{C}}ontrol$ ${\underline{net}}works$) is a standard data communication protocol designed specifically for building automation and control systems. BACnet adopts Master-Slave/Token-Passing (MS/TP) protocol as one of its field level networks. In this study, we introduce a method of implementing bandwidth allocation scheme in the MS/TP protocol. The bandwidth allocation scheme improves the capability of real-time communication of the original MS/TP protocol. The bandwidth allocation scheme introduced in this paper can be easily implemented in the existing MS/TP protocol with a slight modification. In this study, we actually developed the hardware and firmware of MS/TP module in which bandwidth allocation scheme is implemented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.7
• /
• pp.1233-1239
• /
• 2000

In this paper, a new approach is proposed for effectively estimating the occupied bandwidth of frequency modulation (FM) signals. The proposed method makes use of the smoothing niter for removing the perturbation of spectrum envelope, which frequently occurs in FM signals having the instantaneous frequency. An effective procedure is derived for finding the relatively accurate bandwidth of FM signals combined with x-dB bandwidth measurement method, which International Telecommunication Union-Radiocommunication (ITU-R) recommended. It was shown that the proposed approach provides superior performance relative to the one obtained with the x-dB bandwidth measurement method in terms of sample bias and mean squared error of bandwidth estimates.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.223-225
• /
• 2008

In this study. we propose a wide bandwidth surface acoustic wave (SAW) motor by design of Inter Digital Transducer (IDT). SAW motor has several benefits compared with preexisted actuator. But it has narrow bandwidth, which causes the lower performance. To widen the bandwidth, the change of IDT structure was proposed, which is slanted IDT and since function apodization. The frequency responses were compared original uniform IDT and changed IDT. And the time responses were compared original uniform IDT and changed IDT. As a result, the feasibility of wide bandwidth SAW motor was certified.

• Journal of Korean Institute of Industrial Engineers
• /
• v.25 no.3
• /
• pp.404-410
• /
• 1999

A scheme of more exact overflow probability analysis is proposed for traffic regulated by dual leaky bucket. To each regulated traffic stream is allocated bandwidth and buffer independent of other traffic stream and overflow occurs when total bandwidth or buffer allocated to each traffic exceed link capacity or physical buffer size. Ratio of buffer and bandwidth allocated to each traffic stream is assumed to be constant, and this ratio is larger than the ratio of physical buffer and bandwidth due to buffer sharing effect. Numerical experiments show that this sharing effect have significant influence on overflow probability and effective bandwidth.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.4
• /
• pp.165-176
• /
• 2000

Broadband networks are designed to support a wide variety of services with different traffic characteristics and demands for Quality of Services. Bandwidth allocation methods can be classified into two major categories： static and dynamic. In static allocation, bandwidth is allocated only at call setup time and the allocated bandwidth is maintained during a session. In dynamic allocation, the allocated bandwidth is negotiated during a session. The purpose of this paper is to develop policies for deciding and for adjusting the amount of bandwidth requested for a best effort connection over such as ATM networks.. This method is to develop such policies that a good trade off between utilization and latency using cell delay variation to the forecast the incoming traffic in the next period. The performances of the different polices are compared by simulations.

• Journal of Communications and Networks
• /
• v.16 no.2
• /
• pp.146-154
• /
• 2014

This paper proposes a bandwidth-aware localized-routing algorithm that is capable of sensing the available spectrum bands within a two-hop neighboring for choosing the highly opportunistic routes. A mixed-integer linear programming (MILP) is utilized to formulate the optimization problem. Then, the proposed algorithm is used to determine the maximum bandwidth possible of link pairs via a bandwidth approximation process of relaxed variables. Thereby, the proposed algorithm can allow selected routes corresponding to maximum bandwidth possible between cognitive radio (CR) users through link pairs in cognitive radio networks. By comparing the solution values to previous works, simulation results demonstrate that the proposed algorithm can offer a closed-optimal solution for routing performance in cognitive radio networks. The contribution of this paper is achieved through approximately 50% throughput utilized in the network.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.5
• /
• pp.462-466
• /
• 2007

This paper proposes an automatic bandwidth control method for the performance improvement of Binary Amplitude Shift Keying (BASK) system for Giga-Bit Modem in millimeter band. In order to improve the performance of the BASK system with a fixed bandwidth, the proposed method is to adjust a bandwidth of low pass filter in receiver using the fuzzy system. The BASK system consists of a high speed shutter of the transmitter and a counter and a repeater of receiver. The repeater consists of four stage converters, and a converter is constructed with a low pass filter and a limiter. The inputs to the fuzzy system are the reminder and integral of remainder of counter, and output is a bandwidth. We used a Viterbi algorithm to find the optimum detection from the output of the counter. Simulation results showed that the proposed system improves the performance compared to the fixed bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.5
• /
• pp.1200-1207
• /
• 1996

The paper presents and analyzes two efficient burst-level bandwidth reservation protocols for multi-hop ATM Local Area Networks. With the tell-and-wait (TNW) protocol and the tell-and-go (TNG) protocol[6], a negative acknowledgmen(NACK) message representing the bandwidth starvation on a switch on the source-destnation path can be always sent by a destination. We note that the protocols waste more bandwidth as the round-trip delay increases, since the switches on the path must reserve the bandwidth until the NACK will arrive. Based on this pitfall, the proposed protocols allow and ATM node, rather than a destination node to send a NACK. This allowance can save the needless bandwidth wastage. Using the thinned load approximation method, we show the proposed protocols have good performance and practical simplicity. Thus, the proposed protocols may be candidates for the ABR service in multi-hop ATM LANs and ATM WANs.