• Structural Engineering and Mechanics
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• v.39 no.2
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• pp.187-206
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• 2011

This paper uses dynamic computer simulation techniques to develop and apply a multi-criteria procedure using non-destructive vibration-based parameters for damage assessment in truss bridges. In addition to changes in natural frequencies, this procedure incorporates two parameters, namely the modal flexibility and the modal strain energy. Using the numerically simulated modal data obtained through finite element analysis of the healthy and damaged bridge models, algorithms based on modal flexibility and modal strain energy changes before and after damage are obtained and used as the indices for the assessment of structural health state. The application of the two proposed parameters to truss-type structures is limited in the literature. The proposed multi-criteria based damage assessment procedure is therefore developed and applied to truss bridges. The application of the approach is demonstrated through numerical simulation studies of a single-span simply supported truss bridge with eight damage scenarios corresponding to different types of deck and truss damage. Results show that the proposed multi-criteria method is effective in damage assessment in this type of bridge superstructure.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.218-227
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• 2016

Background: Steam explosions may occur in nuclear power plants by molten fuel-coolant interactions when the external reactor vessel cooling strategy fails. Since this phenomenon can threaten structural barriers as well as major components, extensive integrity assessment research is necessary to ensure their safety. Method: In this study, the influence of yield criteria was investigated to predict the failure of a reactor cavity under a typical postulated condition through detailed parametric finite element analyses. Further analyses using a geometrically simplified equivalent model with homogeneous concrete properties were also performed to examine its effectiveness as an alternative to the detailed reinforcement concrete model. Results: By comparing finite element analysis results such as cracking, crushing, stresses, and displacements, the Willam-Warnke model was derived for practical use, and failure criteria applicable to the reactor cavity under the severe accident condition were discussed. Conclusion: It was proved that the reactor cavity sustained its intended function as a barrier to avoid release of radioactive materials, irrespective of the different yield criteria that were adopted. In addition, from a conservative viewpoint, it seems possible to employ the simplified equivalent model to determine the damage extent and weakest points during the preliminary evaluation stage.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.2
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• pp.179-189
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• 2008

The purposes of this study were to segment surrogate internet shopping mall consumers by fashion leadership and to find the differences among the segmented groups in regard to surrogate internet shopping perceived risks, selection criteria, dissatisfactions with surrogate shopping malls, and other purchase behavior. The subjects of this study were female consumers who were users of surrogate internet shopping malls. The data were collected during October, 2005. The respondents returned the questionnaires and 283 questionnaires were finally used in the data analysis. The statistical analyses used for the study were factor analysis, ANOVA, Duncan test, and $X^2$-test. The results showed that consumers were segmented by four groups: fashion dual leaders, fashion leaders, fashion followers, and fashion laggards. These segmented groups were significantly different in regard to surrogate internet shopping mall perceived risks, selection criteria, dissatisfactions with surrogate shopping malls, and other purchase behavior. Generally, fashion dual leaders had less perceived risks, considered diverse selection criteria important, and were less dissatisfied with surrogate shopping malls. Also, the fashion dual leaders had a higher purchase frequency and paid a higher price on surrogate internet shopping malls.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.448-448
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• 2018

In this study, the regression models (Load ESTimator and eight-parameter model) were evaluated to estimate instantaneous pollutant loads under various criteria and optimization methods. As shown in the results, LOADEST commonly used in interpolating pollutant loads could not necessarily provide the best results with the automatic selected regression model. It is inferred that the various regression models in LOADEST need to be considered to find the best solution based on the characteristics of watersheds applied. The recently developed eight-parameter model integrated with Genetic Algorithm (GA) and Gradient Descent Method (GDM) were also compared with LOADEST indicating that the eight-parameter model performed better than LOADEST, but it showed different behaviors in calibration and validation. The eight-parameter model with GDM could reproduce the nitrogen loads properly outside of calibration period (validation). Furthermore, the accuracy and precision of model estimations were evaluated using various criteria (e.g., $R^2$ and gradient and constant of linear regression line). The results showed higher precisions with the $R^2$ values closed to 1.0 in LOADEST and better accuracy with the constants (in linear regression line) closed to 0.0 in the eight-parameter model with GDM. In hence, based on these finding we recommend that users need to evaluate the regression models under various criteria and calibration methods to provide the more accurate and precise results for pollutant load estimations.

• Geomechanics and Engineering
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• v.24 no.3
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• pp.281-293
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• 2021

Uncertainties in geomechanical input parameters which mainly related to inappropriate data acquisition and estimation due to lack of sufficient calibration information, have led wellbore instability not yet to be fully understood or addressed. This paper demonstrates a workflow of employing Quantitative Risk Assessment technique, considering these uncertainties in terms of rock properties, pore pressure and in-situ stresses to makes it possible to survey not just the likelihood of accomplishing a desired level of wellbore stability at a specific mud pressure, but also the influence of the uncertainty in each input parameter on the wellbore stability. This probabilistic methodology in conjunction with Monte Carlo numerical modeling techniques was applied to a case study of a well. The response surfaces analysis provides a measure of the effects of uncertainties in each input parameter on the predicted mud pressure from three widely used failure criteria, thereby provides a key measurement for data acquisition in the future wells to reduce the uncertainty. The results pointed out that the mud pressure is tremendously sensitive to UCS and SHmax which emphasize the significance of reliable determinations of these two parameters for safe drilling. On the other hand, the predicted safe mud window from Mogi-Coulomb is the widest while the Hoek-Brown is the narrowest and comparing the anticipated collapse failures from the failure criteria and breakouts observations from caliper data, indicates that Hoek-Brown overestimate the minimum mud weight to avoid breakouts while Mogi-Coulomb criterion give better forecast according to real observations.

• International journal of advanced smart convergence
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• v.13 no.3
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• pp.259-266
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• 2024

One of the most time consuming issues in a city development is the identification of suitable areas for urban infrastructures and proper land uses. Suitability analysis is the process and procedures to find the best available land in given area -that is, the ability of a system to select the needs of users in land use. This paper studied the usage of Geographic Information System technique and methods for the selection of the most appropriate sites for public park in the city of Gwangju. GIS was used as a standard technique to find the best available sites for development in urban areas. For this cause, digital elevation model and spatial data were used to produce different thematic layers by using software Idrisi. Criteria for finding the suitable site for park development were decided to evaluate the land and the followings 4 criteria were selected: on land with less than 3 degrees in slope, outside a 200m buffer around lakes, on land currently designated as forests, and 20ha or greater in size. To meet and measure each criterion, distance and context operators were applied to reclassify the importance of certain weight and Boolean images were generated to meet the criteria. These weights and maps has been combined using ArcGIS tools and the final map was prepared showing the most suitable sites. We may assist city planners and government officials in future development of public facilities including parks and related land use plans at urban level and act as to ensure proper land use planning and management of the urban areas.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.9-15
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• 2017

Background: The purpose of this study is to assign an appropriate density to virtual phantom for 2D diode array detector with different dose calculation algorithms to guarantee the accuracy of patient-specific QA. Materials and Methods: Ten VMAT plans with 6 MV photon beam and ten VMAT plans with 15 MV photon beam were selected retrospectively. The computed tomography (CT) images of MapCHECK2 with MapPHAN were acquired to design the virtual phantom images. For all plans, dose distributions were calculated for the virtual phantoms with four different materials by AAA and AXB algorithms. The four materials were polystyrene, 455 HU, Jursinic phantom, and PVC. Passing rates for several gamma criteria were calculated by comparing the measured dose distribution with calculated dose distributions of four materials. Results and Discussion: For validation of AXB modeling in clinic, the mean percentages of agreement in the cases of dose difference criteria of 1.0% and 2.0% for 6 MV were $97.2%{\pm}2.3%$, and $99.4%{\pm}1.1%$, respectively while those for 15 MV were $98.5%{\pm}0.85%$ and $99.8%{\pm}0.2%$, respectively. In the case of 2%/2 mm, all mean passing rates were more than 96.0% and 97.2% for 6 MV and 15 MV, respectively, regardless of the virtual phantoms of different materials and dose calculation algorithms. The passing rates in all criteria slightly increased for AXB as well as AAA when using 455 HU rather than polystyrene. Conclusion: The virtual phantom which had a 455 HU values showed high passing rates for all gamma criteria. To guarantee the accuracy of patent-specific VMAT QA, each institution should fine-tune the mass density or HU values of this device.

• Science of Emotion and Sensibility
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• v.14 no.2
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• pp.279-292
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• 2011

This research explores the differences of two consumption behaviors from the thinking style they elicit. Specifically, we predict that more utilitarian attributes(vs. hedonic attributes) may be used when evaluating utilitarian products whereas more hedonic attributes(vs. utilitarian attributes) may be used when evaluating hedonic products. In addition, this research considered two different thinking styles: rational thinking style and experiential thinking style, and try to find out whether different product attribute information could elicit different thinking style and whether the thinking style has any effect on product evaluation. The data reported in this research demonstrates the following results. Firstly, people use different criteria when judging different types of product. That is, when judging utilitarian product, they are more likely to use utilitarian attribute as evaluation criteria, on the contrary they inclined to use hedonic attribute as evaluation criteria when choosing hedonic product. Secondly, different types of attribute informations could elicit different thinking style. Utilitarian attribute informations elicit rational thinking style whereas hedonic attribute informations elicit experiential thinking style. Finally, if people engage in rational thinking elicited in processing utilitarian attribute informations, the evaluation of utilitarian product is enhanced. But even though people engage in experiential thinking in processing hedonic attribute informations, the evaluation of hedonic product is not improved.

• Journal of Intelligence and Information Systems
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• v.22 no.3
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• pp.23-43
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• 2016

As a result of the growth of Internet data and the rapid development of Internet technology, "big data" analysis has gained prominence as a major approach for evaluating and mining enormous data for various purposes. Especially, in recent years, people tend to share their experiences related to their leisure activities while also reviewing others' inputs concerning their activities. Therefore, by referring to others' leisure activity-related experiences, they are able to gather information that might guarantee them better leisure activities in the future. This phenomenon has appeared throughout many aspects of leisure activities such as movies, traveling, accommodation, and dining. Apart from blogs and social networking sites, many other websites provide a wealth of information related to leisure activities. Most of these websites provide information of each product in various formats depending on different purposes and perspectives. Generally, most of the websites provide the average ratings and detailed reviews of users who actually used products/services, and these ratings and reviews can actually support the decision of potential customers in purchasing the same products/services. However, the existing websites offering information on leisure activities only provide the rating and review based on one stage of a set of evaluation criteria. Therefore, to identify the main issue for each evaluation criterion as well as the characteristics of specific elements comprising each criterion, users have to read a large number of reviews. In particular, as most of the users search for the characteristics of the detailed elements for one or more specific evaluation criteria based on their priorities, they must spend a great deal of time and effort to obtain the desired information by reading more reviews and understanding the contents of such reviews. Although some websites break down the evaluation criteria and direct the user to input their reviews according to different levels of criteria, there exist excessive amounts of input sections that make the whole process inconvenient for the users. Further, problems may arise if a user does not follow the instructions for the input sections or fill in the wrong input sections. Finally, treating the evaluation criteria breakdown as a realistic alternative is difficult, because identifying all the detailed criteria for each evaluation criterion is a challenging task. For example, if a review about a certain hotel has been written, people tend to only write one-stage reviews for various components such as accessibility, rooms, services, or food. These might be the reviews for most frequently asked questions, such as distance between the nearest subway station or condition of the bathroom, but they still lack detailed information for these questions. In addition, in case a breakdown of the evaluation criteria was provided along with various input sections, the user might only fill in the evaluation criterion for accessibility or fill in the wrong information such as information regarding rooms in the evaluation criteria for accessibility. Thus, the reliability of the segmented review will be greatly reduced. In this study, we propose an approach to overcome the limitations of the existing leisure activity information websites, namely, (1) the reliability of reviews for each evaluation criteria and (2) the difficulty of identifying the detailed contents that make up the evaluation criteria. In our proposed methodology, we first identify the review content and construct the lexicon for each evaluation criterion by using the terms that are frequently used for each criterion. Next, the sentences in the review documents containing the terms in the constructed lexicon are decomposed into review units, which are then reconstructed by using the evaluation criteria. Finally, the issues of the constructed review units by evaluation criteria are derived and the summary results are provided. Apart from the derived issues, the review units are also provided. Therefore, this approach aims to help users save on time and effort, because they will only be reading the relevant information they need for each evaluation criterion rather than go through the entire text of review. Our proposed methodology is based on the topic modeling, which is being actively used in text analysis. The review is decomposed into sentence units rather than considering the whole review as a document unit. After being decomposed into individual review units, the review units are reorganized according to each evaluation criterion and then used in the subsequent analysis. This work largely differs from the existing topic modeling-based studies. In this paper, we collected 423 reviews from hotel information websites and decomposed these reviews into 4,860 review units. We then reorganized the review units according to six different evaluation criteria. By applying these review units in our methodology, the analysis results can be introduced, and the utility of proposed methodology can be demonstrated.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.405-410
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• 2020

Professionalism, objectivity, and fairness are highly required in the assessment of tasks in national research and development projects. Experts in the technologies should thus focus on the task's plan in the review process. The same scores in the assessment, however, do not mean that the judges don't have the same opinions. Another problem is the possibility that different weights can be applied for evaluation indexes. This study proposed an AHP-based assessment criteria decision system for national research and development tasks to reduce errors in task assessment and selection and improve the professionalism and fairness by objectifying the evaluation criteria of each index. As a result, the assessment criteria were objectified for each index in the projects. In addition, the professionalism and fairness of experts were secured in the process of setting assessment criteria for each index based on the given marks of weights.