• Journal of Auto-vehicle Safety Association
• /
• v.13 no.4
• /
• pp.123-128
• /
• 2021

This paper present box feature estimation from LiDAR point cluster using maximum likelihood Method. Previous LiDAR tracking method for autonomous driving shows high accuracy about velocity and heading of point cluster. However, Assuming the average position of a point cluster as the vehicle position has a lower accuracy than ground truth. Therefore, the box feature estimation algorithm to improve position accuracy of autonomous driving perception consists of two procedures. Firstly, proposed algorithm calculates vehicle candidate position based on relative position of point cluster. Secondly, to reflect the features of the point cluster in estimation, the likelihood of the particle scattered around the candidate position is used. The proposed estimation method has been implemented in robot operating system (ROS) environment, and investigated via simulation and actual vehicle test. The test result show that proposed cluster position estimation enhances perception and path planning performance in autonomous driving.

• Journal of the Korean Statistical Society
• /
• v.28 no.2
• /
• pp.235-251
• /
• 1999

In this paper we examine extremal behavior of a $textsc{k}$th-order stationary Markov chain {X\ulcorner} by considering excesses over a high level which typically appear in clusters. Excesses over a high level within a cluster define a cluster damage, i.e., a normalized sum of all excesses within a cluster, and all excesses define a damage point process. Under some distributional assumptions for {X\ulcorner}, we prove convergence in distribution of the cluster damage and obtain a representation for the limiting cluster damage distribution which is well suited for simulation. We also derive formulas for the mean and the variance of the limiting cluster damage distribution. These results guarantee a compound Poisson limit for the damage point process, provided that it is strongly mixing.

• 한국방재학회:학술대회논문집
• /
• 2007.02a
• /
• pp.575-578
• /
• 2007

The objective of this study is to analyze the regionalization of point rainfall by statistical methods for regional frequency analysis of the rainfall. The rainfall data used in this study are annual maximum rainfall at 57 stations during the period of more than 30 years for 12 durations(10min, 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24hr) in Korea. The Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance of nonparametric test the principal component and the cluster analysis have been performed to analyze the regionalization of rainfall. The results of this study are as follows; (1) The region which hydrological homogeneous is accepted does not exist for whole duration in Korea. (2) The result of nonpametric test shows that hydrological homogeneous regions of point rainfall are divided by 5 regions. (3) In case of cluster analysis hydrological homogeneous regions of point rainfall are divided by 6 regions and 4 other areas.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.4 no.3
• /
• pp.337-340
• /
• 2004

The clustering problem can be formulated as the problem to find the number of clusters and a partition matrix from a given data set using the iterative or non-iterative algorithms. The author proposes a nearest neighbor and validity-based clustering algorithm where each data point in the data set is linked with the nearest neighbor data point to form initial clusters and then a cluster in the initial clusters is linked with the nearest neighbor cluster to form a new cluster. The linking between clusters is continued until no more linking is possible. An optimal set of clusters is identified by using the conventional cluster validity index. Experimental results on well-known data sets are provided to show the effectiveness of the proposed clustering algorithm.

• Korean Journal of Mathematics
• /
• v.12 no.1
• /
• pp.41-47
• /
• 2004

We introduce the $K_0$-proximity space as a generalization of the Efremovi$\check{c}$-proximity space. We try to show every ultrafilter in $K_0$-proximity space generates a cluster and every Cauchy cluster is a point cluster.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.05a
• /
• pp.447-449
• /
• 2021

Various wireless sensor network protocols have been proposed to maintain the network for a long time by minimizing energy consumption. Using the K-means clustering algorithm takes longer to cluster than traditional hierarchical algorithms because the center point must be moved repeatedly until the final cluster is established. For K-means clustering-based protocols, only the residual energy of nodes or nodes near the center point of the cluster is considered when the cluster head is elected. In this paper, we propose a new wireless sensor network protocol based on K-means clustering to improve the energy efficiency while improving the aforementioned problems.

• Journal of Korean Society on Water Environment
• /
• v.37 no.6
• /
• pp.520-530
• /
• 2021

Multivariate statistical analysis and an environmental hydrological model were applied for investigating the causes of water pollution and providing best management practices for water quality improvement in urban and agricultural watersheds. Principal component analysis (PCA) and cluster analysis (CA) for water quality time series data show that chemical oxygen demand (COD), total organic carbon (TOC), suspended solids (SS) and total phosphorus (T-P) are classified as non-point source pollutants that are highly correlated with river discharge. Total nitrogen (T-N), which has no correlation with river discharge and inverse relationship with water temperature, behaves like a point source with slow and consistent release. Biochemical oxygen demand (BOD) shows intermediate characteristics between point and non-point source pollutants. The results of the PCA and CA for the spatial water quality data indicate that the cluster 1 of the watersheds was characterized as upstream watersheds with good water quality and high proportion of forest. The cluster 3 shows however indicates the most polluted watersheds with substantial discharge of BOD and nutrients from urban sewage, agricultural and industrial activities. The cluster 2 shows intermediate characteristics between the clusters 1 and 3. The results of hydrological simulation program-Fortran (HSPF) model simulation indicated that the seasonal patterns of BOD, T-N and T-P are affected substantially by agricultural and livestock farming activities, untreated wastewater, and environmental flow. The spatial analysis on the model results indicates that the highly-populated watersheds are the prior contributors to the water quality degradation of the river.

• Korean Journal of Mathematics
• /
• v.10 no.1
• /
• pp.5-10
• /
• 2002

In this paper, we investigate the prefilter base on a fuzzy set and fuzzy net ${\varphi}$ on the fuzzy topological space (X,${\delta}$). And we show that the prefilter base $\mathcal{B}({\varphi})$ determines by the fuzzy net ${\varphi}$ converge to a fuzzy point $p$ iff the fuzzy net ${\varphi}$ converge to a fuzzy point $p$. Also we prove that if the prefilter base $\mathcal{B}$ converge to a fuzzy point $p$, then the $\mathcal{B}$ has the cluster point $p$.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.06a
• /
• pp.67-71
• /
• 2003

In order to manage a cluster system that consists of a number servers, management aspects such as configuration management, fault management, performance management, and user management should be considered. Especially, it is necessary to monitor performances for performance and fault management. An agent in each server collects performance counters, status changes, and events occurred in normal or abnormal states. The data collected are delivered to a collector sorter and processed in a report tool for performance analysts and management decision in the cluster system point of view, by detecting fault state and tracing out resource usage, service response, and response, and states until failed. In this paper we propose an architecture modeling of a performance report tool for proactive cluster system management. Some results on a cluster system are presented.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.17 no.2
• /
• pp.247-264
• /
• 1993

This study deals with the manufacturing of the foundation garments for the well-balanced somatotype of the Korean middle-aged womenhood. In order to get hold of the different somatotypes, a survey of a total of 134 middle-aged women in Kwangju area, ranging in their age from 45 through 59 was made. The statistical methods used for the analysis of the basic data were the Pearson's correlation coefficient, Anova, Cluster analysis and Stepwise. Emphasis of the try-on test was placed on (1) the comparison of anthropometric data before and after trying on the foundation garments, (2) sensory evaluation, (3) a rating on fit and performance, (4) the comparison by means of photograph. The conclusions obtained are as follows : 1) The 134 women sampled and measured were classified into the five groups of somatotype : the 52 women (34%) belong to Cluster 1 ; the 22 women(14.5%) belong in Cluster 2 ; the 12 women(7.9%) belong in Cluster 3 ; the 15 women(9.9%) belong in Cluster 4 ; the 33 women(27.7%) belong to Cluster 5. 2) As for the characteristics of the foundation garment design, the V-shaped neckline and chest dart was used. The adjust point is right above the perineum point. The foundation garment length is as far as trochanteric point. The materials used are cotton/polyurethane, lace, 100%cotton. The materials used for corrections were the sponge pad for the chest, and non-woven fabric pad for the back, shoulder and the hip. 3) The comparison of the anthropometric data of the subject when dressed in foundation garments showed a significant difference in bust point height, in bust point length and in nipple-ta-nipple breadth, which proves the foundation garments to be effective in correcting such part as the chest, the hip and the abdomen. 4) As considered in terms of the sensory evaluation, the item except for the shoulder and the armhole coincided with each other in the mean value and in the composite reliability coefficient, which also proves the foundation garments to be effective. 5) Subjects were satisfactory on fit, performance, design, of the foundation garment, and their changed appearance. 6) In the case of the comparison through the photographs, the silhouettes of all the five women subjects were found effectively to be balanced.