• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.754-759
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• 2007

This study exploits the data discriminating capability of silhouette statistics, which combines wavelet-based vertical energy threshold technique for the purpose of extracting damage-sensitive features and clustering signals of the same class. This threshold technique allows to first obtain a suitable subset of the extracted or modified features of our data, i.e., good predictor sets should contain features that are strongly correlated to the characteristics of the data without considering the classification method used, although each of these features should be as uncorrelated with each other as possible. The silhouette statistics have been used to assess the quality of clustering by measuring how well an object is assigned to its corresponding cluster. We use this concept for the discriminant power function used in this paper. The simulation results of damage detection in a truss structure show that the approach proposed in this study can be successfully applied for locating both open- and breathing-type damage even in the presence of a considerable amount of process and measurement noise.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.593-598
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• 2005

At-site analysis is not appropriate if the record length is shorter than target return period T. If the record length is longer than 27 years, then at-site analysis may be sufficient(Institute of Hydrology, 1999). However, in such a case, regional frequency analysis is recommended for purpose of comparison. Record lengths of annual maximum rainfall data in Korea are usually shorter than 50 years. It is therefore essential to apply regional frequency analysis for estimating rainfall quantiles of more than 100 years return period. In this research, regional rainfall frequency analysis is performed for hourly rainfall data of South Korea. Homogeneous regions are idntified by clusgter analysis which is a standard method of statistical multivariate analysis for dividing a data set into groups. An appropriate distribution is chosen by goodness-of-fit test. GLO is found to be an appropriate distribution as a result of goodness-of-fit measure (Hosking & Wallis, 1997). Simulation experiments are performed to check the performance of frequency analysis techniques. The effects of discordant sites on quantiles are considered.

• Journal of Distribution Research
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• v.10 no.3
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• pp.87-101
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• 2005

Market segmentation has been an important issue in marketing for a long time. Many models and statistical methods have been developed by many scholars. The purpose of this research provides one insight for market segmentation based on clustering technique in channel benefit sought. We proposed a sequential approach in market segmentation. A sequential approach means that we do market segmentation by multi-stage method based on the benefits sought in marketing channel. To achieve this approach, we divided the main benefits sought into subcategories. That is to say, after dividing each benefit sought into more detailed concepts, we did market segmentation sequentially.

• Journal of the Korean Home Economics Association
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• v.47 no.2
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• pp.97-110
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• 2009

The purpose of this study was to exam the effects of sociocultural attitude toward appearance on perceptual attitudinal body images and clothing behaviors. The research method was survey and the subjects were 447 male and female adolescents in Daejeon. The questionnaire consisted of 4 measuring instruments; sociocultural attitude toward appearance, perceptual and attitudinal body images, clothing behaviors, and subject’s demographic attributions. The data were analyzed by Cronbach's $\alpah$, x$^2$ test, t-test, factor analysis, cluster analysis, using SPSS program. The results were as follows. Adolescents had relatively high level recognition and internalization of sociocultural value toward appearance, and they perceived very thin body type as ideal body and had high interest of their appearance and weight. Sociocultural attitude toward appearance had important effects on adolescents' perceptual and attitudinal body images and clothing behaviors. The adolescents who are receptive to sociocultural value toward appearance had the tendency to distort their body as fat, showed high interest of their appearance and weight, and also showed high clothing interest & psychological dependency, clothing ostentation, and clothing conformity, but low clothing comfort than those who are not receptive to sociocultural value toward appearance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.52-58
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• 2007

This paper presents the wind-power model for generation adequacy assessment. Both wind-power and system load depend on time of a year and show their periodic nature with similar periods. Therefore, the two quantities have some probabilistic relations, and if one of them is given, the other can be decided with some probability. In this paper, the two quantities are quantized by k-means clustering algorithm and related probabilities among the cluster centers are calculated using sequential wind-power and system load data. The proposed model is highly expected to be applied for generation adequacy assessment by Monte-Carlo simulation with state sampling method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.216-216
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• 2003

The layered nickel oxides (LiNiO$_2$) have been studied for possible use as cathode materials i3l 4V lithium batteries. Although LiCoO$_2$ has been known as the best candidate material for Li-ion batteries, which produces the best performance LiNiO$_2$ is generally accepted as an attractive cathode material, because of its various advantages such as lower cost higher discharge capacity and better reversibility. In this investigation, we calculated the electric state of LiNiO$_2$ using DV-X$\alpha$ molecular orbital method in order to obtain the information of chemical bonding among the Li, Ni and O. In LiNiO$_2$, alternate layers of Li and Ni occupy the octahedral sites of a cubic close packing of oxide ions, making up a rhombohedral structure with an R-3m space group, Li in 3a, Ni in 3b, and O in 6c sites. On the basis of this, we made the cluster model and studied ionization of each atoms and interaction between atoms according to Mullilcen population analysis.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.15 no.1
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• pp.19-36
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• 2004

This study was to investigate brand image and its influence on customers perception of fast-food restaurants. A total of 25 brand image attributes were selected on the basis of the literature review and were asked to indicate respondents' perceptions of their image targeting for fast-food restaurants such as Lotteria, McDonald, KFC, and Popeyes. A on-site survey method was applied to collect data. Out of 300 distributed survey questionnaire, a total of 271 useful sample were collected and analyzed in SPSS 10.0. From the factor analysis with 25 brand image attributes, five underline dimensions were identified and named such as interior factor, store factor, atmosphere factor, service factor, and product factor. Then, T-test and ANOVA were conducted to investigate any differences between/among the groups based on those five brand image factors. The results provided that in terms of gender, age, preference for fast food, food cluster, and four different brand, customers differently perceived restaurant brand image. It is hoped that this information may help for restaurant managers and marketers to understand customers' restaurant perception and choice behavior in order to launch appropriate marketing strategies.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.73-82
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• 2001

The aim of this study is to provide the basic data for clothing construction of pre-school children by the result of the analyses and classifications of children's upper body somatotypes. The objects of this study are the bodies of 220 male pre-school children from 3 to 6 years old. The method of anthropometric measurement is the direct and photographic measurement. After analysing the measurements, 7 factors were extracted and the factors were applied to the cluster analysis. As the results, the 4 types were classified. Type 1 was characterized by the shortest and normal body one among these four types. This type showed the forward-curved back, the projected abdomen, and the fallen shoulders. Type 2 was characterized by the normal height and the fattest body type. Type 3 was characterized by the slimmest body and the shorter height type. Type 4 was characterized by the tallest and normal body with the rising shoulders.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.8
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• pp.418-428
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• 2005

In this paper, a new probabilistic generation modeling method which can address the characteristics of changed electricity industry is proposed. The major contribution of this paper can be captured in the development of a probabilistic generation modeling considering generator maintenance outage and in the classification of market demand into multiple demand clusters for the applications to electricity markets. Conventional forced outage rates of generators are conceptually combined with maintenance outage of generators and, consequently, effective outage rates of generators are newly defined in order to properly address the probabilistic characteristic of generation in electricity markets. Then, original market demands are classified into several distinct demand clusters, which are defined by the effective outage rates of generators and by the inherent characteristic of the original demand. We have found that generators have different effective outage rates values at each classified demand cluster, depending on the market situation. From this, therefore, it can be seen that electricity markets can also be classified into several groups which show similar patterns and that the fundamental characteristics of power systems can be more efficiently analyzed in electricity markets perspectives, for this classification can be widely applicable to other technical problems in power systems such as generation scheduling, power flow analysis, price forecasts, and so on.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1147-1161
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• 2015

Nowadays we are considering and analyzing not only classical data expressed by points in the p-dimensional Euclidean space but also new types of data such as signals, functions, images, and shapes, etc. Symbolic data also can be considered as one of those new types of data. Symbolic data can have various formats such as intervals, histograms, lists, tables, distributions, models, and the like. Up to date, symbolic data studies have mainly focused on individual formats of symbolic data. In this study, it is extended into datasets with both histogram and multimodal-valued data and a divisive clustering method for the mixed feature-type symbolic data is introduced and it is applied to the analysis of industrial accident data.