• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.355-364
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• 2009

A simple method is proposed for constructing nonparametric confidence intervals for the difference or ratio of two median failure times. The method applies when clustered survival data with censoring is randomized either (I) under cluster randomization or (II) subunit randomization. This method is simple to calculate and is based on non-parametric density estimation. The proposed method is illustrated with the otology study data and HL-A antigen study data. Moreover, the simulation results are reported for practical sample sizes.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.593-596
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• 2004

We introduce a method of identifying evidence of shocks in the X-ray emitting gas in clusters of galaxies. Using information from synthetic observations of simulated clusters, we do a blind search of the synthetic image plane. The locations of likely shocks found using this method closely match those of shocks identified in the simulation hydrodynamic data. Though this method assumes nothing about the geometry of the shocks, the general distribution of shocks as a function of Mach number in the cluster hydrodynamic data can be extracted via this method. Characterization of the cluster shock distribution is critical to understanding production of cosmic rays in clusters and the use of shocks as dynamical tracers.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.69-75
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• 2009

In this paper, we proposed CPLD low power algorithm using reduce glitch power consumption. Proposed algorithm generated a feasible cluster by circuit partition considering the CLB condition within CPLD. Glitch removal process using delay buffer insertion method for feasible cluster. Also, glitch removal process using same method between feasible clusters. The proposed method is examined by using benchmarks in SIS, it compared power consumption to a CLB-based CPLD low power technology mapping algorithm for trade-off and a low power circuit design using selective glitch removal method. The experiments results show reduction in the power consumption by 15% comparing with that of and 6% comparing with that of.

• Journal of Korea Multimedia Society
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• v.17 no.6
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• pp.655-670
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• 2014

In this paper, we propose an efficient and robust lane detection method for detecting immediate left and right lane boundaries of the lane in the roads. The proposed method are based on hyperbolic lane model and the reliable line segment clustering. The reliable line segment cluster is determined from the most probable cluster obtained from clustering line segments extracted by the efficient LSD algorithm. Experiments show that the proposed method works robustly against lanes with difficult environments such as ones with occlusions or with cast shadows in addition to ones with dashed lane marks, and that the proposed method performs better compared with other lane detection methods on an CMU/VASC lane dataset.

• The KIPS Transactions:PartB
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• v.17B no.2
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• pp.177-182
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• 2010

This paper proposes a new document clustering method using PCA and fuzzy association. The proposed method can represent an inherent structure of document clusters better since it select the cluster label and terms of representing cluster by semantic features based on PCA. Also it can improve the quality of document clustering because the clustered documents by using fuzzy association values distinguish well dissimilar documents in clusters. The experimental results demonstrate that the proposed method achieves better performance than other document clustering methods.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.2
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• pp.138-143
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• 2006

In this paper, we have presented a Sequential Agglomerative Hierarchical Nested (SAHN) algorithm-based data clustering method in fuzzy inference system to achieve optimal performance of fuzzy model. SAHN-based algorithm is used to give possible range of number of clusters with cluster centers for the system identification. The axes of membership functions of this fuzzy model are optimized by using cluster centers obtained from clustering method and the consequence parameters of the fuzzy model are identified by standard least square method. Finally, in this paper, we have observed our model's output performance using the Box and Jenkins's gas furnace data and Sugeno's non-linear process data.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.127-132
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• 2014

This paper describes a robust speech recognition technique by reconstructing spectral components mismatched with a training environment. Although the cluster-based reconstruction method can compensate the unreliable components from reliable components in the same spectral vector by assuming an independent, identically distributed Gaussian-mixture process of training spectral vectors, the presented method exploits the temporal dependency of speech to reconstruct the components by introducing a hidden-Markov-model prior which incorporates an internal state transition plausible for an observed spectral vector sequence. The experimental results indicate that the described method can provide temporally consistent reconstruction and further improve recognition performance on average compared to the conventional method.

• Journal of The Korean Astronomical Society
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• v.40 no.4
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• pp.91-97
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• 2007

The Fokker-Planck (FP) model is one of the commonly used methods for studies of the dynamical evolution of dense spherical stellar systems such as globular clusters and galactic nuclei. The FP model is numerically stable in most cases, but we find that it encounters numerical difficulties rather often when the effects of tidal shocks are included in two-dimensional (energy and angular momentum space) version of the FP model or when the initial condition is extreme (e.g., a very large cluster mass and a small cluster radius). To avoid such a problem, we have developed a new integration scheme for a two-dimensional FP equation by adopting an Alternating Direction Implicit (ADI) method given in the Douglas-Rachford split form. We find that our ADI method reduces the computing time by a factor of ${\sim}2$ compared to the fully implicit method, and resolves problems of numerical instability.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.39-51
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• 1998

In this paper, we propose signaling procedures amon network elements for a connection rerouting method which can reduce inter-switch handoff processing delay reduces the delay in the connection re-routing by reserving VPI/VCIs for possible inter-switch handoff calls in advance. Additionally, we mathematically analyze the signaling procedures and then suggest solutions to the relations with cluser size, network topoloty, handoff-request rete and handoff delay. With simulation, the solutions are validated. From numerical examples, we concluded taht handoff delay, one of the handoff QoSs, can be satisfied by adjusting the cluster size and network topology according to the handoff -request rate of service area. With our proposed signaling and analytic methods, we concluded that the connection rerouting method using cluster-sectoring effectively reduces the delay of inter-switch handoff processing than dynamic connection rerouting method. Our solutions are useful in guaranteeing the requested handoff delay (especially, inter-switch handoff delay) when the connection rerouting method is applied to ATM-based wireless/wired integrated network.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.134-138
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• 2000

Signal words such as DANGER, WARNING, CAUTION, etc. have been used in order to transmit a potential hazard easily and quickly. But they were applied to a number of the sites without consistency. Thus, this study took Quantification Method and Cluster Analysis in order to judge the signal words corresponding to the urgency of situations, and to analyze whether signal words are used properly or not. According to the result of Quantification Method II signal words were most affected by Understanding, Severity and Likelihood in both student group and industrial worker group. And in Quantification Method III CAUTION corresponded to Immediacy and Understanding whereas NOTICE did to Receptivity, WARNING, DEADLY and DANCER did to Likelihood, Dangerousness and Severity. Finally, Cluster Analysis showed that CAUTION and NOTICE were recognized as similar words.