• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.466-473
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• 2020

A marine air drone is a new device that can be used to respond to and prevent marine casualties. Determining the districts where marine air drones can be deployed helps the government decision makers identify efficient policy. The aim of this study is to develop a model using the fuzzy-analytic hierarchy process (F-AHP) and additive ratio assessment (ARAS) method to evaluate appropriate districts for deploying marine air drones. To verify the applicability of the proposed model, a case study was performed with respect to the Korea coast guard (KCG) districts. Since the deployed marine air drones are characterized by a high degree of overlap between the evaluation attributes. the F-AHP is used to determine the weights of identified criteria. The results of this study, show that missing people from the shore was the most important criterion for deployment of the drone. For ranking the local districts of the KCG, the ARAS is applied in the case study with the single goal of 50% reduction in marine casualties. Consequently, the highest priority district was identified as Mokpo, followed by Incheon, Seogwipo, Taean, Wando, Yeosu, Pohang, Tongyeong, Gunsan, Bolyeong, Jeju, Buan, Donghae, Sokcho, Ulsan, Uljin, Busan, Changwon, and Pyeongtaeg.

• Journal of Korea Technology Innovation Society
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• v.10 no.2
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• pp.183-205
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• 2007

An investigation was undertaken of the optimal discriminant model for predicting the likelihood of insolvency in advance for medium-sized firms based on the technology evaluation. The explanatory variables included in the discriminant model were selected by both factor analysis and discriminant analysis using stepwise selection method. Five explanatory variables were selected in factor analysis in terms of explanatory ratio and communality. Six explanatory variables were selected in stepwise discriminant analysis. The effectiveness of linear discriminant model and logistic discriminant model were assessed by the criteria of the critical probability and correct classification rate. Result showed that both model had similar correct classification rate and the linear discriminant model was preferred to the logistic discriminant model in terms of criteria of the critical probability In case of the linear discriminant model with critical probability of 0.5, the total-group correct classification rate was 70.4% and correct classification rates of insolvent and solvent groups were 73.4% and 69.5% respectively. Correct classification rate is an estimate of the probability that the estimated discriminant function will correctly classify the present sample. However, the actual correct classification rate is an estimate of the probability that the estimated discriminant function will correctly classify a future observation. Unfortunately, the correct classification rate underestimates the actual correct classification rate because the data set used to estimate the discriminant function is also used to evaluate them. The cross-validation method were used to estimate the bias of the correct classification rate. According to the results the estimated bias were 2.9% and the predicted actual correct classification rate was 67.5%. And a threshold value is set to establish an in-doubt category. Results of linear discriminant model can be applied for the technology financing banks to evaluate the possibility of insolvency and give the ranking of the firms applied.

• Journal of Navigation and Port Research
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• v.44 no.4
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• pp.319-325
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• 2020

The Korean government has been pursuing many supporting programs to enhance the competition of water transportation companies in recent years. To implement the policies effectively, which needs its monitering and evaluates about their business performance. The purpose of this study was to evaluate the business performance of water transportation company groups and determine the outranking between the groups using the Integrated Fuzzy AHP-PROMETHEE.. To achieve this purpose, first, the companies were classified into seven alternative company groups and the criteria for their evaluation was extracted Second, the weights of the criteria, by maritime and port expert survey, were calculated using the Fuzzy AHP. This paper, finally, determined the total priority orders of their company groups as the link Fuzzy PROMETHEE II with weights of the criteria and the local priority orders between them using the Fuzzy PROMETHEE I. In the proposal for this model, thus was collected four criteria such as growth ability, beneficial ability, technical ability, and productive ability. Through the result of this evaluation, the other marine transportation services group was determined as the highest outranking but the inland passenger & cargo transportation services group was lowest. Thus, the developing plan of the productive ability for the other marine transportation services group should be reviewed to continue its good performance, and all off the criteria for the inland passenger & cargo transportation services group to raise the performance should be reviewed.

• Korean Journal of Health Education and Promotion
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• v.22 no.1
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• pp.1-16
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• 2005

The study was performed to examine the scaling behavior about dental health. The subjects of this study were 700 workers selected in Daegu. This survey was carried out during 2003. 7. 15 - 2003. 7. 31. The results of this study can be summarized as follows. 1. Distribution of respondent's class was male of $53.5\%, female of $46.2\%, and 30's age of $36.2\%, 20's age of $28.2\%. Concerning about dental health was appeared that female was higher rate than male. also, difference was related in their age, working department and residence. 2. In case of no experience to scaling for past 3 years was appeared that male of $67.6\% was higher rate than female of $56.8\%. The frequency of treat scaling was appeared that $46.2\% of the subjects was treated scaling per year. 3. The root cause of no treatment by regular was appeared that 'high expensive' was most high with $38.0\% and 2nd, 'didn't felt importance' was $24.2\%, 3rd 'lack of spare time' was $20.7\%, the last ranking 'only be frightened' was $14.3\%. 4. Method of learning knowledge about scaling was appeared that male and female were similar with their method of it. knowledge level of scaling was learned by internet were higher in worker of 20's age than any other age. also, other difference was related in school career and residence. Opinion about necessity of scaling answer which need or surely need were similar to male of $67.1\% and female of $72.6\%. 5. As for knowledge of scaling was appeared that male of $94.3\% and female of $87.1\% had corrective knowledge. The right answer was significantly different by ages, school career, working department and residence.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.1861-1864
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• 2016

Although early diagnosis of thyroid nodule type is very important, the diagnostic accuracy of standard tests is a challenging issue. We here aimed to find an optimal combination of factors to improve diagnostic accuracy for distinguishing malignant from benign thyroid nodules before surgery. In a prospective study from 2008 to 2012, 345 patients referred for thyroidectomy were enrolled. The sample size was split into a training set and testing set as a ratio of 7:3. The former was used for estimation and variable selection and obtaining a linear combination of factors. We utilized smoothly clipped absolute deviation (SCAD) logistic regression to achieve the sparse optimal combination of factors. To evaluate the performance of the estimated model in the testing set, a receiver operating characteristic (ROC) curve was utilized. The mean age of the examined patients (66 male and 279 female) was $40.9{\pm}13.4years$ (range 15- 90 years). Some 54.8% of the patients (24.3% male and 75.7% female) had benign and 45.2% (14% male and 86% female) malignant thyroid nodules. In addition to maximum diameters of nodules and lobes, their volumes were considered as related factors for malignancy prediction (a total of 16 factors). However, the SCAD method estimated the coefficients of 8 factors to be zero and eliminated them from the model. Hence a sparse model which combined the effects of 8 factors to distinguish malignant from benign thyroid nodules was generated. An optimal cut off point of the ROC curve for our estimated model was obtained (p=0.44) and the area under the curve (AUC) was equal to 77% (95% CI: 68%-85%). Sensitivity, specificity, positive predictive value and negative predictive values for this model were 70%, 72%, 71% and 76%, respectively. An increase of 10 percent and a greater accuracy rate in early diagnosis of thyroid nodule type by statistical methods (SCAD and ANN methods) compared with the results of FNA testing revealed that the statistical modeling methods are helpful in disease diagnosis. In addition, the factor ranking offered by these methods is valuable in the clinical context.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.62-71
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• 2013

This study is conducted for the purpose of analyzing and contemplating the problems with the competition in current landscape design, with the goal of improving the landscape design competition system by using the AHP technique. The result of this study, first describe the Landscape design competition system that formed the problems and show the most important problem followed by other problems shown in order of importance, which are 'design changes after winning', 'Guidelines for design competition' and 'Landscape design competition manner'. Secondly, in the low rank article make up the level one -From a total 12 elements from the low rank article corresponding in 'process of winner selection' the 'Unprofessional landscape participate the screening' collected comments for the biggest problem, 'lack of expertise in judgement', 'problems with the examination scoring system' and other articles, the corresponding in 'process of winner selection' appears at the highest ranks. It also happens that after making the choice in the landscape design competition, the importance of 'client's design change symptoms' appears high. As a result the overlooked details of the landscape design competition's problems were analyzed. This study has prioritized the problems by problems which landscape design competition institutions most frequently have. Based on this ranking, there is significance purpose to create proactive system improvements in the future. By analyzing these problems, we will be better able to develop improvements to the future system.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.351-367
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• 1999

This study aims to study the discourses influencing high school students' concept and attitude toward mathematics, and to examine how gender differences concerning mathematical aptitude are created. This study is based on the results of previous two studies which suggested that mathematical competence differs not only according to gender, region and school year, but also even within the same gender. For this study, 12 students ranking in the top 10% at two co-ed high schools were interviewed to find out 1) what discourses are related to gender and mathematics, 2) in what way these discourses are formulated and gain currency, and 3) how they have affected students in general. Common notions concerning mathematics may be summed up as follows: 1) Most of the students believe that gender difference in mathematical aptitude results because biologically men tend to be strong in mathematics and analytical skills while women tend to have better linguistic ability. This concept can help male students' studying to have a greater learning toward mathematics. 2) A large number of the students believe that male students' studying method is based on comprehension whereas female students' method is based on retention, and hence the former group tends to be better at applying their learning than the latter group. This notion seres to encourage male students and discourage female students from tackling difficult mathematical problems. 3) Many students believe that, although female students may surpass their male counterparts in middle school or the first year of high school, they will eventually fall behind by the 3rd year. Despite research which shows that these common beliefs are not grounded in scientific proof, high-school girls, who may be strong in mathematics, lose self-confidence and feel a sense of crisis. The mechanisms which produce and reinforce such concepts as those mentioned above can be summarized as follows: 1) Regarding the choice of majors and future career paths, parents show different attitudes toward sons and daughters, and this tends to influence high-school girls and hinders them from entering mathematics-related fields. 2) Teachers with value systems based on stereo-typed gender roles affect students a great deal, and give different advice according to gender of their students, for selecting their major fields - for instance, whether to study the natural sciences as opposed to humanities. 3) This study indicates that peer-group behavior, of either support or exclusion, also reinforces the process of internalizing notions of gender difference related to mathematical aptitude. 4) The gender-based notion that men are naturally more inclined to have better mathematical ability has caused male students to choose the natural science subjects and female students to turn to the humanities. The discourses discussed above, propagated in schools and homes, and in the mass media, are continually reinforced along with general gender inequalities in the society at large.

• Korean Journal of Construction Engineering and Management
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• v.9 no.5
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• pp.159-167
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• 2008

This study provides a effective approach to the construction management problem with the limited number or amount of available resources using the analytic hierarchy process. Construction management is a series of decision making processes for planning and controling of cost, time and quality as main objectives in construction works. When several activities need the limited same resource at the same time, it is very hard to decide the priority of the activities in the real situations. For that the scientific decision making method and procedure for resource allocation are required. This study solves the resource allocation problem by dealing with the decision making problem which the activities are distributed to multiple projects and under multiple criteria. The analytic hierarchy process is a method devised to solve complex multi-criteria decision problems. The result shows that this study can be effectively used to make decisions in situations involving multiple objectives by evaluating the prioritized ranking and degree of the activity alternatives based on the overall preferences.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.229-239
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• 2016

The aim of this paper is to extend the TOPSIS(Technique for Order Performance by Similarity to Ideal Solution) to the fuzzy environment for solving the new professor selection problem in a university. In order to achieve the goal, the rating of each candidate and the weight of each criterion are described by linguistic terms which can be expressed in trapezoidal fuzzy numbers. In this paper, a vertex method is proposed to calculate the distance between two trapezoidal fuzzy numbers. According to the concept of the TOPSIS, a closeness coefficient is defined to determine the ranking order of all candidates. This research derived; 1) 4 evaluation criteria(research results, education and research competency, personality, major suitability) for new professor selection, 2) the 5 step procedure of the proposed fuzzy TOPSIS method for the group decision, 3) priorities of 4 candidates in the new professor selection case. The results of this paper will be useful to practical expert who is interested in analyzing fuzzy data and its multi-criteria decision-making tool for personal selection problem in personal management. Finally, the theoretical and practical implications of the findings were discussed and the directions for future research were suggested.

• The Journal of the Acoustical Society of Korea
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• v.37 no.3
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• pp.147-155
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• 2018

In this paper, we tried to find out sound quality metrics to express discomfort of overload excavator noise and to develop sound quality indexes through multiple regression analysis by using them. For this purpose, the interior noise of cabin under overload condition was recorded for six excavator models with different noise properties and Jury test was carried out by PCM (Paired Comparison Method) and MEM (Magnitude Estimation Method). Jury test result with low consistency was classified into two groups with different preference tendencies by cluster analysis and multiple regression analysis was conducted in order to find out which sound quality metrics have significant effects on discomfort(low preference). As a result, we figured out that the sound quality metrics to express the discomfort were the partial loudness (= $PN_{10Bark}$) between 0 and 10 Bark in case of group1 and the difference between engine noise(= $dB_{EG}$) and hydraulic system noise ($dB_1$) in case of group2. Using the results of preference ranking and tendency analysis of PCM followed by the correlation analysis between PCM and MEM, the more reliable results were adopted by excluding the data with low consistency obtained from Jury test via MEM.