• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.1
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• pp.76-82
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• 2000

In this paper, we consider nonparametric signal detection problems under the presence of additive noise exhibiting weak dependence We derive the test statistics of the locally optimum rank detectors under a weakly dependent noise model for known and random signal cases The performance characteristic of the locally optimum rank detectors are analyzed in terms of asymptotic relative efficiency.

• ETRI Journal
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• v.35 no.4
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• pp.687-696
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• 2013

The development of proxy caching is essential in the area of video-on-demand (VoD) to meet users' expectations. VoD requires high bandwidth and creates high traffic due to the nature of media. Many researchers have developed proxy caching models to reduce bandwidth consumption and traffic. Proxy caching keeps part of a media object to meet the viewing expectations of users without delay and provides interactive playback. If the caching is done continuously, the entire cache space will be exhausted at one stage. Hence, the proxy server must apply cache replacement policies to replace existing objects and allocate the cache space for the incoming objects. Researchers have developed many cache replacement policies by considering several parameters, such as recency, access frequency, cost of retrieval, and size of the object. In this paper, the Weighted-Rank Cache replacement Policy (WRCP) is proposed. This policy uses such parameters as access frequency, aging, and mean access gap ratio and such functions as size and cost of retrieval. The WRCP applies our previously developed proxy caching model, Hot-Point Proxy, at four levels of replacement, depending on the cache requirement. Simulation results show that the WRCP outperforms our earlier model, the Dual Cache Replacement Policy.

• Journal of Industrial Convergence
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• v.15 no.2
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• pp.1-6
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• 2017

This paper illustrates key features of an enterprise employment simulation which integrates a system dynamic feedback model with a cost-effectiveness optimisation capability utilising genetic algorithms. Its core is a 3-dimensional array structure tracking staff numbers by rank, by time-in-rank, by years-of-service. The resultant model, which could readily be adapted to non-Defence use, can identify, given user specification of any mix of employment rules, the likely patterns of employment behaviour including: resultant time-in-rank and years-of-service profiles; ability of a Unit to fill all positions to target strength; ability to fill promotional positions within normal rules for substantive promotion; need to fill promotional positions using rules for temporary promotion or transfer from outside; necessary recruitment pattern to sustain target strength.

• The Korean Journal of Applied Statistics
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• v.21 no.5
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• pp.783-789
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• 2008

We investigate the effects of the misspecification of cointegrating(CI) ranks at other frequencies on the inference of seasonal models at the frequency of interest; our study includes tests for CI ranks and estimation of CI vectors. Earlier studies focused mostly on a single frequency corresponding to one seasonal root at a time, ignoring possible cointegration at the remaining frequencies. We investigate the effects of the mis-specification, especially in finite samples, by adopting Gaussian reduced rank(GRR) estimation by Ahn and Reinsel (1994) that considers cointegration at all frequencies of seasonal unit roots simultaneously. It is observed that the identification of the seasonal CI rank at the frequency of interest is sensitive to the mis-prespecification of the CI ranks at other frequencies, mainly when the CI ranks at the remaining frequencies are underspecified.

• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.75-86
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• 2002

We consider the problem of estimating the change-point in mean change model with one change-point. Gombay and Huskova(1998) derived a class of change-point estimators with the score function of rank. A change-point estimator with the log score function of rank is suggested and is shown to be involved in the class of Gombay and Huskova(1988). The simulation results show that the proposed estimator has smaller rose, larger proportion of matching the true change-point than the other estimators considered in the experiment when the change-point occurs in the middle of the sample.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.3
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• pp.25-36
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• 2020

Topics calculated using LDA topic modeling have to be labeled separately. When labeling a topic, we look at the words that represent the topic, and label the topic. Therefore, it is important to first make a good set of words that represent the topic. This paper proposes a method of calculating a set of words representing a topic using TextRank, which extracts the keywords of a document. The proposed method uses Relevance to select words related to the topic with discrimination. It extracts topic keywords using the TextRank algorithm and connects keywords with a high frequency of simultaneous occurrence to express the topic with a higher coverage.

• Journal of the Korean Data and Information Science Society
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• v.11 no.2
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• pp.279-293
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• 2000

This article suggests two change-point estimators which are modifications of Carlstein(1988) change-point estimators with rank functions and mean functions where there is one change-point in a mean function. A comparison study of Carlstein(1988) estimators and proposed estimators is done by simulation on the mean, the MSE, and the proportion of matching true change-point.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4C
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• pp.336-341
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• 2008

In this paper, beamforming algorithm is proposed which can obtain diversity gain in beamforming system that deploy antenna elements with half-wavelength. The proposed algorithm provides beam-pattern using eigen-vectors that span received signal subspace. The criterion to decide optimal rank of eigen-space used for beamforming is also proposed. A beamforming system applied the proposed algorithm shows better performance with diversity gain as getting larger angle spread. This paper provides a description of proposed algorithm with analysis of the performance using various computer simulations.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.800-803
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• 1996

This paper proposes the algorithm to solve emergency service restoration problems using efficient reconfiguration method in distribution system. In this algorithm, we try to avoid the blackout of important loads by considering service rank. It is possible to reconfigurate the system by using fuzzy inference results in which was reflected the expected distribution power, line capacity and service rank. A 27-bus, 32-branch model system is used to demonstrate the effectiveness of the proposed algorithm.

• The Korean Journal of Applied Statistics
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• v.20 no.1
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• pp.147-157
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• 2007

Edge detection has been widely used in computer vision and image processing. We describe a new edge detector based on the robust rank-order test which is a useful alternative to Wilcoxon test. Our method is based on detecting pixel intensity changes between two neighborhoods with a $r{\times}r$ window using an edge-height model to perform effectively on noisy images. Some experiments of our robust rank-order detector with several existing edge detectors are carried out on both synthetic images and real images with and without noise.