• Journal of the Korean Data and Information Science Society
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• v.9 no.1
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• pp.19-27
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• 1998

We considered the bandwidth selection method which has asymptotic optimal convergence rate $n^{-1/2}$ in kernel regression function estimation. For the proposed bandwidth selection, we considered Mean Averaged Squared Error as a performance criterion and its Taylor expansion to the fourth order. Then we estimate the bandwidth which minimizes the estimated approximate value of MASE. Finally we show the relative convergence rate between optimal bandwidth and proposed bandwidth.

• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.607-617
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• 2003

This paper offers a practical comparison of efficiency between local likelihood approach and conventional kernel approach in density estimation. The local likelihood estimation procedure maximizes a kernel smoothed log-likelihood function with respect to a polynomial approximation of the log likelihood function. We use two types of data driven bandwidths for each method and compare the mean integrated squares for several densities. Numerical results reveal that local log-linear approach with simple plug-in bandwidth shows better performance comparing to the standard kernel approach in heavy tailed distribution. For normal mixture density cases, standard kernel estimator with the bandwidth in Sheather and Jones(1991) dominates the others in moderately large sample size.

• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.441-446
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• 2003

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. The PON architecture is very simple but it requires a MAC protocol for control of upstream traffic. The MAC protocol must support QoS (Quality of Service) administration function by various traffic class, efficient dynamic bandwidth assignment function, CDV (Ceil Delay Variation) minimization function etc. This paper proposes a dynamic bandwidth assignment algorithm of the MAC protocol for a broadband access network using an Ethernet Passive Optical Network supporting various traffic class. We compare our proposed with MDRR algorithm using simulation, and confirmed that our proposed Request-Counter algorithm produces shorter average cell delay.

• The Korean Journal of Applied Statistics
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• v.7 no.1
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• pp.149-158
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• 1994

Nonparametric regression technique using kernel estimator is an attractive alternative that has received some attention, recently. The kernel estimate depends on two quantities which have to be provided by the user : the kernel function and the bandwidth. However, the more difficult problem is how to find an appropriate bandwidth which controls the amount of smoothing (see Silverman, 1986). Thus, in practical situation, it is certainly desirable to determine an appropriate bandwidth in some automatic fashion. Thus, the problem is to find a data-driven or adaptive (i.e., depending only on the data and then directly computable in practice) bandwidth that performs reasonably well relative to the best theoretical bandwidth. In this paper, we introduce a relation between bias and variance of mean square error. Thus, we present a simple and effective algorithm for selecting local bandwidths in kernel regression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3642-3646
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• 2012

In this paper, the bandwidth of the filters used in optical communication systems and systems for the correlation between the error probability has been studied. Preamplifier that occurs in the system error probability as a function of the sensitivity of the receiver on the receiver sensitivity was shown for the various error probability calculation is performed. In addition, the channel data rate on the probability of various errors, changes in the function of the optimal bandwidth for the receiver filter was calculated, as required to operate at optimal range of the filter bandwidth, data rate per channel in a 10Gb/s the range of when is between 0.2 and 3.5nm.

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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.702-708
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• 2019

The range resolution of echo sounders can be improved by enhancing the transducer bandwidth. We designed a bandpass matching network for expanding the bandwidth of a transducer by scaling in both impedance and frequency after transforming a lowpass network into a bandpass configuration for a third-order Bessel filter. We measured the effect of the Bessel matching network for a 50 kHz sandwich type transducer on the transmitting voltage response (TVR), receiving sensitivity (SRT) and figure of merit (FOM), using a chirp echo sounder system. Both the simulation and experimental results indicated that the transducer with a bandpass matching network was capable of producing a symmetrical acoustic output over a wider bandwidth (8.25 kHz) than was the transducer without a matching network (3.75 kHz). By implementing the Bessel matching network, we achieved a 120% bandwidth enhancement.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.951-958
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• 2004

Nowadays NGN is developed for supporting the e-Commerce, Internet trading, e-Government, e-mail, virtual-life and multimedia. Internet gives us the benefit of remote access to the information but causes the attacks that can break server and modify information. Since 2000 Nimda, Code Red Virus and DSoS attacks are spreaded in Internet. This attack programs make tremendous traffic packets on the Internet. In this paper, we designed and developed the Bandwidth Controller in the gateway systems against the bandwidth saturation attacks. This Bandwidth con-troller is implemented in hardware chipset(FPGA) Virtex II Pro which is produced by Xilinx and acts as a policing function. We reference the TBF(Token Bucket Filter) in Linux Kernel 2.4 and implemented this function in HDL(Hardware Description Language) Verilog. This HDL code is synthesized in hardware chipset and performs the gigabit traffic in real time. This policing function can throttle the traffic at the rate of band width controlling policy in bps speed.

• Journal of the Korean Statistical Society
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• v.22 no.2
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• pp.361-368
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• 1993

In recent years, kernel type estimates are abundant. In this paper, we propose a bandwidth selection method for kernel regression of fixed design based on bootstrap procedure. Mathematical properties of proposed bootstrap-based bandwidth selection method are discussed. Performance of the proposed method for small sample case is compared with that of cross-validation method via a simulation study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11B
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• pp.1007-1015
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• 2003

In this Paper, we propose a method of determining the price for the elastic traffic in the current or future Internet services. First, we investigate the behavior in the consumption of bandwidth of elastic traffic in IP network. Next, we propose a new method to relate the bandwidth usage with the pricing for the elastic traffic, which is based partially or fully on the usage rate of the network bandwidth. Next, we propose an optimal charging function for elastic traffic, which is applicable to any Internet services. Finally, we will illustrate the implication of the work via simple numerical experiments.