• Journal of the Korean Operations Research and Management Science Society
• /
• v.36 no.1
• /
• pp.39-55
• /
• 2011

Process monitoring has been emphasized for the monitoring of complex system such as chemical processing industries to achieve the efficiency enhancement, quality management, safety improvement. Recently, ICA (Independent Component Analysis) based MSPC (Multivariate Statistical Process Control) was widely used in process monitoring approaches. Moreover, DICA (Dynamic ICA) has been introduced to consider the system dynamics. However, the existing approaches show the limitation that their performances are strongly dependent on the statistical distributions of control variables. To improve the limitation, we propose a novel approach for process monitoring by integrating DICA and LOF (Local Outlier Factor). In this paper, we aim to improve the fault detection rate with the proposed method. LOF detects local outliers by using density of surrounding space so that its performance is regardless of data distribution. Therefore, the proposed method not only can consider the system dynamics but can also assure robust performance regardless of the statistical distributions of control variables. Comparison experiments were conducted on the widely used benchmark dataset, Tennessee Eastman process (TE process), and showed the improved performance than existing approaches.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.12
• /
• pp.1107-1114
• /
• 2011

In this paper, the fatigue life of a laser peened structure was predicted. In order to calculate residual stress induced by laser peening finite element simulation was carried out. Modified Goodman equation was used to consider the effect of compressive residual stress induced by laser peening in fatigue analysis. In addition, additive adjustment factor approach was applied to consider S-N curve model uncertainty. Consequently, the reliable bounds of the predicted fatigue life of the laser peened structure was determined.

• Structural Engineering and Mechanics
• /
• v.84 no.5
• /
• pp.675-684
• /
• 2022

The conventional single-degree-of-freedom (SDOF) system is appropriate for dynamic response analysis of paneltype structures without an opening. However, the typical building structures usually have four-sided fixed walls having an opening. Therefore, it may induce a considerable error when dynamic responses are estimated based on the conventional SDOF system, since the SDOF system cannot consider the effect of an opening during the SDOF analysis. For this reason, this study proposes a new SDOF system to consider the effect of an opening by adjusting its load-mass factor. The load-mass factor can be modified based on the assumption that the behaviors of the four-sided fixed wall with an opening is very similar to the behaviors of the same size wall without an opening, when the uniformly distributed blast loaded area is identical. In order to confirm a feasibility of the proposed SDOF system, a series of numerical simulations were carried out for the four-sided fixed reinforced concrete (RC) wall under a blast load. The dynamic responses estimated from the proposed SDOF system and the conventional SDOF system were compared with the dynamic responses evaluated from the finite element (FE) analysis. Especially, for the maximum dynamic responses except for 50% opening case, the proposed SDOF system had about 1.1% to 25.7% normalized errors while the conventional SDOF system had about 4.1% to 49.1% normalized errors.

• Journal of Information Processing Systems
• /
• v.7 no.2
• /
• pp.341-354
• /
• 2011

Analyzing the relationships among the parameters for quantifying the quality of research published in journals is a challenging task. In this paper, we analyze the relationships between the impact factor, h-index, and g-index of a journal. To keep our analysis simple and easy to understand, we consider a generalized version of the impact factor where there is no time window. In the absence of the time window, the impact factor converges to the number of citations received per paper. This is not only justified for the impact factor, it also simplifies the analysis of the h-index and g-index as well because addition of a time window in the form of years complicates the computation of indices too. We derive the expressions for the relationships among impact factor, h index, and g-index and validate them using a given set of publication-citation data.

• Korean journal of food and cookery science
• /
• v.30 no.3
• /
• pp.360-367
• /
• 2014

This study analyzed the Importance-Performance Analysis of selective attributes of Ethnic Food Restaurant. A total of 369 questionnaires were analyzed. Five factors were obtained from factor analysis of Importance variance of selective attributes of Ethnic food restaurant: Factor 1 "Quality", Factor 2 "Service", Factor 3 "Physical environment", Factor 4 "Uniqueness", Factor 5 "Health". Also, "Quality", "Physical environment", "Uniqueness" factors influenced overall satisfaction. In addition, according to the IPA results, selective attributes with low satisfaction and high importance in the second quadrant were 'Sanitation that comfort hospitality', 'Level of service' and 'Price'. These results suggest that when customers select Ethnic food restaurant, they consider 'food price' and 'food quality'. Therefore, manager of ethnic food restaurant should take these improvement factors into consideration in order to meet consumer's expectations.

• The Journal of the Korea Contents Association
• /
• v.16 no.11
• /
• pp.409-419
• /
• 2016

The purpose of this study is to examine the differences of selecting coffee shop and type of coffee according to the reason for the visit. The proposed model was empirically tested by using survey data collected from 209 university students in Seoul and Gyeonggi Province. SPSS has been used to preform this analysis. The study found six reasons for visiting Coffee shops which are convenience, social contact, psychological factor, economic factor, mental factor, and habitual visit. As we gorup these six reasons into three groups, students who visit coffee shops according to economic or habitual factor consider more on 'diversity of coffee'. And students who visit coffee shops according to convenience or habitual factor consider more on 'kindness of worker'. And last group who visit coffee shops according to social factor consider more on 'moderate price of coffee'. The reason why the reason for the visit and the attributes of selecting Coffee Shop are not meaningful to the type of coffee which students chose is that most of students tend to choose certain type such as Americano. And this also result from the traditional managements which don't have enough effort or the differentiation about the variety of menu.

• Journal of Digital Convergence
• /
• v.13 no.11
• /
• pp.417-425
• /
• 2015

The purpose of this study is to verify differences between Korean and Chinese consumers in consideration, shopping value, the extent of purchase satisfaction and intent to revisit the site when people use social commerce. When Korean and Chinese consumers use social commerce, it was confirmed that they look at four things; economical efficiency, practical, informativeness, and convenience. There are the following results. Firstly, it was found that in the case of using social commerce, economical efficiency as a factor of consideration was higher in Chinese consumers than Korean consumers. Secondly, practical of social commerce concerns the social commerce site's trustworthiness and stability, and also the popularity of the site and ease in which users can use the site. In this, this factor is more important to Chinese consumers than Korean consumers. Thirdly, in the factors of informativeness, which means product information and quality, and buyers comments, there was no confirmed difference between Korean and Chinese consumers. Fourth, in the convenience factor, there was a difference found between Korean and Chinese consumers.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.53-58
• /
• 2009

Solar photovoltaic power generation system is judging that by the most suitable new refreshing energy in real condition of our country forward continuously interest for solar photovoltaic power generation system and diffusion me enlarged. Output decline problem is item to consider necessarily and should be verified in continuous interest for solar photovoltaic power generation system are diffusion. Present plan that minimize output decline calculating module liver optimum interval that consider recitation of a poem to reduce output decline by module liver shade by incidence angle consideration and this that occupy most parts among factor because do output of solar photovoltaic power generation system well.

• Journal of Korean Institute of Industrial Engineers
• /
• v.29 no.2
• /
• pp.145-149
• /
• 2003

We consider the estimation of failure rate and acceleration factor under type-I censoring without using acceleration model when testing is conducted in only one highly accelerated condition. Failure times of an item are assumed to be exponentially distributed. It is also assumed that the uncertainty about the acceleration factor, the failure time contraction ratio between accelerated condition and use condition, can be modeled by the uniform or gamma prior distribution of appropriate parameters. We respectively use Bayes and maximum likelihood approaches to estimate acceleration factor and failure rate in the use condition. An example is given to show how the method can be applied.

• Journal of the Korean Data and Information Science Society
• /
• v.18 no.4
• /
• pp.1191-1203
• /
• 2007

In this paper, we consider the hypothesis testing for the homogeneity of the shape parameters in the gamma distributions. The noninformative priors such as Jeffreys# prior or reference prior are usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we propose the objective Bayesian testing procedure for the homogeneity of the shape parameters based on the fractional Bayes factor and the intrinsic Bayes factor under the reference prior. Simulation study and a real data example are provided.