• Korean Management Science Review
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• v.21 no.2
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• pp.191-213
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• 2004

This study addresses the evaluation criteria of multimedia authoring tools(MATs), the way which decision-maker can exclude outlier matrix from group using the concept of the compatibility index, and how AHP can be applied to the selection of MATs in a group decision-making environment. The AHP technique allows an evaluator to quantify the relative importance of elements at each hierarchy and to calculate the composite relative weights for each product(i.e. MATs). This decision process allows setting to priority of the MATs based on the AHP. The results indicated that technical ability of MATs was the most significant factor in affecting their decision, trailed by managerial efficiency and vendor support. To the experts, multimedia data support was the less important than development interface. Also, the results indicated that product A(0.510) was their first choice, trailed by product C(0.286) and B(0.204). Assessing the composite relative weights revealed that expert group's members were consistent with the rankings of decision variables(evaluation criteria variables) statistically in selecting their MATs. Therefore, we believed that expert group's members have achieved sufficient agreement to permit the use of geometric mean to average the group's preference without obscuring the differences of individual opinions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1223-1232
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• 2004

This study is directed toward determining the number and characteristics of psychologically meaningful perceptual dimensions required for assessing the sound quality with respect to vehicle noises, and toward identifying the acoustical and/or psychoacoustical bases underlying the preference and similarity judgments. For the purpose of analyzing the paired comparison data produced by subjective ratings we used nonmetric multidimensional scaling(MDS). The perceptual dimensions based upon preference ratings could explain 76.3 % of the variance by maximum dB(A) and sharpness acum. The correlation between objective and subjective positions of the stimuli is $R^2$=0.97(F(1,13)=195.45, p < .01), corrected $R^2$=0.93. The less the intensity of the stimulus the more becomes the subjective Position would be over-estimated relative to the objective one. The same is valid for the opposite case. The perceptual dimensions based upon similarity judgments could be accounted for 47.8 % and 23.5% of the variance, each of which might be a match for the maximum dB(A) and the sharpness acum, respectively. The correlation between objective and subjective positions of the stimuli is $R^2$=0.94(F(1,13)=92.38, p < .01), corrected $R^2$=0.87. The more the intensity of the stimulus the more becomes the subjective position would be over-estimated relative to the objective one. The same is valid for the opposite case. In other words, it is likely that the larger the amount of two stimuli which to compare would be judged similar. So far it should be further clarified that whether the relationship between preference ratings and psychological distances nay be optimized through which psycho-physical models.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1051-1059
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• 2015

Wave runup is one of the most important factors affecting the design of coastal structure exposed to wave attack. In this study, two dimensional laboratory tests were conducted under the different random wave conditions and structure configurations to develop a formula to predict runup heights. Rubble-mound structure consisted of tetrapod armour blocks with 1:1.5 and 1:2 slopes. The relative water depths (the ratio of the significant wave height to water depth at the toe) ranged from 0.14 to 0.56. The formula proposed here is applicable to surf similarity parameter ranging from 2 to 6. Runup heights on 1:2 slope were higher than those on 1:1.5 slope. Runup heights were reduced by 5% when the armour layer thickness increased two times.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.535-542
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• 2013

Since case-based reasoning(CBR) has many advantages, it has been used for supporting decision making in various areas including medical checkup, production planning, customer classification, and so on. However, there are several factors to be set by heuristics when designing effective CBR systems. Among these factors, this study addresses the issue of selecting appropriate neighbors in case retrieval step. As the criterion for selecting appropriate neighbors, conventional studies have used the preset number of neighbors to combine(i.e. k of k-nearest neighbor), or the relative portion of the maximum similarity. However, this study proposes to use the absolute similarity threshold varying from 0 to 1, as the criterion for selecting appropriate neighbors to combine. In this case, too small similarity threshold value may make the model rarely produce the solution. To avoid this, we propose to adopt the coverage, which implies the ratio of the cases in which solutions are produced over the total number of the training cases, and to set it as the constraint when optimizing the similarity threshold. To validate the usefulness of the proposed model, we applied it to a real-world target marketing case of an online shopping mall in Korea. As a result, we found that the proposed model might significantly improve the performance of CBR.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.999-1009
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• 2014

Hierarchical clustering analysis helps easily exploring massive microarray data and understanding biological phenomena with dendrogram. But, because hierarchical clustering algorithms only consider the absolute similarity, it is difficult to illustrate a relative dissimilarity, which consider not only the distance between a pair of clusters, but also how distant are they from the rest of the clusters. In this study, we introduced the relative hierarchical clustering method proposed by Mollineda and Vidal (2000) and compared hierarchical clustering method and relative hierarchical method using the simulated data and the real data in the various situations. The evaluation of the quality of two hierarchical methods was performed using percentage of incorrectly grouped points (PIGP), homogeneity and separation.

• Journal of Advanced Research in Ocean Engineering
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• v.2 no.1
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• pp.22-27
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• 2016

This experimental study deals with the mechanism of spoilers that cause scouring around pipelines. The design methodology was applied to spoilers for accelerating pipelines that undergo self-burial into the sand-bed and evaluated using approaching experimental analysis. The experimental study was conducted to investigate the self-burial ability of submarine pipelines with two types of sand-bed models: silt and sand. Spoilers of different heights were attached to the top of the pipeline for each experiment case. The relationship between the relative scour depth and spoiler height was evaluated by applying different flow velocities and sand diameters and comparative analysis was performed with values obtained from similarity experiments and theory. The experimental study will be useful in establishing a database for the design of spoilers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.157-163
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• 2001

Introgression from genetically modified plants (GMPs) may be dependent on the genetic similarity to wild relative plants. In Korea, many wild plant species are botanically related to the cultivated plants that have a potential to be genetically transformed. The controversy for hazards of GMPs is continuing because the studies on gene flow or introgression are little. Based on the systematic criteria, we have surveyed Korean wild plant species that showed the similarity to cultivating crops. The consideration for feasibility of genetic pollution (introgression of transgene) is necessary for the successful accomplishment in the practical use of GMPs. Although the detrimental effects of GMPs on wild relatives have not been clearly verified, Korean wild plant species related to crop plant (potential GMP) have to be investigated with respect to the introgression. Korean flora consists of ca. 5,500 species. Among them, 1,448 species are classified as weed species (966 native, 325 naturalized, and 167 escaped ones), which is vulnerable to GMPs in term of introgression. We suggested the principal Korean wild plants related to major crops that might be affected by GMPs via introgression. The investigated species herein are selected based on the morphological and phenological relationship. It is necessary to verify the genetic relationship between cultivated plants and wild relatives sing more precise molecular techniques, which provide the information of likelihood for the introgression of transgene.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.1
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• pp.32-41
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• 2010

DEA(Data Envelopment Analysis) is the relative efficiency measure among homogeneous DMU(Decision- Making Units) which can be used to useful tool to improve performance through efficiency evaluation and benchmarking. However, the general case of DEA was considered as unrealistic since it consists a benchmarking regardless of DMU characteristic by input and output elements and the high efficiency gap in benchmarking for inefficient DMU. To solve this problem, stratification method for benchmarking was suggested, but simply presented benchmarking path in repeatedly applying level. In this paper, we suggest a new method that inefficient DMU can choice the optimal path to benchmark the most efficient DMU base on the similarity among the input elements. For this, we propose a route choice method that combined a stratification benchmarking algorithm and SOM (Self-Organizing Map). An implementation on real environment is also presented.

• Atmosphere
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• v.24 no.4
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• pp.471-479
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• 2014

A road surface temperature prediction model (UM-Road) using input data of the Unified Model (UM) output and road physical properties is developed and verified with the use of the observed data at road weather information system. The UM outputs of air temperature, relative humidity, wind speed, downward shortwave radiation, net longwave radiation, precipitation and the road properties such as slope angles, albedo, thermal conductivity, heat capacity at maximum 7 depth are used. The net radiation is computed by a surface radiation energy balance, the ground heat flux at surface is estimated by a surface energy balance based on the Monin-Obukhov similarity, the ground heat transfer process is applied to predict the road surface temperature. If the observed road surface temperature exists, the simulated road surface temperature is corrected by mean bias during the last 24 hours. The developed UM-Road is verified using the observed data at road side for the period from 21 to 31 March 2013. It is found that the UM-Road simulates the diurnal trend and peak values of road surface temperature very well and the 50% (90%) of temperature difference lies within ${\pm}1.5^{\circ}C$ (${\pm}2.5^{\circ}C$) except for precipitation case.

• KCID journal
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• v.17 no.2
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• pp.17-27
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• 2010

In order to manage the water quality in reservoir, it is necessary to understand the temporal and spatial variation of reservoirs and to classify the reservoirs. In this research, agricultural reservoirs are classified according to physical characteristics (depth, residence time, shape of the reservoir etc) and water quality using multivatriate analysis (PCA and CA). CA (Cluster Analysis) method classify reservoirs into several groups as a similarity of the reservoirs, but it is difficult to indicate a full list to the one table. In case of PCA (Principle Component Analysis) method, it has the advantage for the classification on the reservoirs depending on the water quality similarity and also it is useful to analyze the relationship between related factors through correlation analysis. However PCA is limited to classify into several groups based on the characteristics of the reservoirs and each user should be classified as randomly subjective according to the relative position of the reservoir in the figure. In conclusions, compared to conventional reservoirs classification methods, both CA and PCA methods are considered to be a classification method that describes the nature of the reservoir well, but classification results has a restriction on use, so further research will be needed to complement.