• Information Systems Review
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• v.13 no.3
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• pp.123-139
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• 2011

This paper researches the value of domestic telecommunication bundle products. Customers evaluate each telecommunication products differently according to their attributes. The attributes affecting the customer value of telecommunication bundling can be categorized in 3 ones as follows; corporate image, service feature, and service price. Also authors analyze the difference of importancy that customers consider when they evaluate each products, and propose the optimal scenario for bundling. In conclusion, other two companies A, C excluding B should invest more resources into the portion that strengthen the attributes of company image, and service feature to upgrade their 'corporate image', and 'service feature'. According to 6-scenarios analysis on the bundle products, the QPS expansion of company A was the most advantageous position, but if companies B, C expand DPS made use of their strengths, they can prevent from decreasing additivity rapidly with sequential scenario. The above results show that one company may have equable power in each area, but if another company having strengths in special areas makes up for its weakness and differentiates gradually it can contribute to strengthen its competitiveness. This contributed much more theoretical and practical than the existing researches. Supposing that additivity index evaluated by consumers can be changed by efforts of companies, this scenario planning is the result of study showing that the investment and publicity of each company have to be considered as its characteristic of each product at the same time.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.317-329
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• 2014

In vision measurement systems based on structured light, the key point of detection precision is to determine accurately the central position of the projected laser line in the image. The purpose of this research is to extract laser line centers based on a decision function generated to distinguish the real centers from candidate points with a high recognition rate. First, preprocessing of an image adopting a difference image method is conducted to realize image segmentation of the laser line. Second, the feature points in an integral pixel level are selected as the initiating light line centers by the eigenvalues of the Hessian matrix. Third, according to the light intensity distribution of a laser line obeying a Gaussian distribution in transverse section and a constant distribution in longitudinal section, a normalized model of Hessian matrix eigenvalues for the candidate centers of the laser line is presented to balance reasonably the two eigenvalues that indicate the variation tendencies of the second-order partial derivatives of the Gaussian function and constant function, respectively. The proposed model integrates a Gaussian recognition function and a sinusoidal recognition function. The Gaussian recognition function estimates the characteristic that one eigenvalue approaches zero, and enhances the sensitivity of the decision function to that characteristic, which corresponds to the longitudinal direction of the laser line. The sinusoidal recognition function evaluates the feature that the other eigenvalue is negative with a large absolute value, making the decision function more sensitive to that feature, which is related to the transverse direction of the laser line. In the proposed model the decision function is weighted for higher values to the real centers synthetically, considering the properties in the longitudinal and transverse directions of the laser line. Moreover, this method provides a decision value from 0 to 1 for arbitrary candidate centers, which yields a normalized measure for different laser lines in different images. The normalized results of pixels close to 1 are determined to be the real centers by progressive scanning of the image columns. Finally, the zero point of a second-order Taylor expansion in the eigenvector's direction is employed to refine further the extraction results of the central points at the subpixel level. The experimental results show that the method based on this normalization model accurately extracts the coordinates of laser line centers and obtains a higher recognition rate in two group experiments.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.94-101
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• 2012

This paper proposes an improved image steganalysis scheme to raise the detection rate of stego images out of cover images. To improve the detection rate of stego image in the steganalysis, tiny variation caused by data hiding should be amplified. For this, we extract feature vectors of cover image and stego image by two steps. First, we separate image into upper 4 bit subimage and lower 4 bit subimage. As a result, stego noise is expanded more than two times. We decompose separated subimages into twelve subbands by applying 3-level Haar wavelet transform and calculate co-occurrence probabilities of two different subbands in the same scale. Since co-occurrence probability of the two wavelet subbands is affected by data hiding, it can be used as a feature to differentiate cover images and stego images. The extracted feature vectors are used as the input to the multilayer perceptron(MLP) classifier to distinguish between cover and stego images. We test the performance of the proposed scheme over various embedding rates by the LSB, S-tool, COX's SS, and F5 embedding method. The proposed scheme outperforms the previous schemes in detection rate to existence of hidden message as well as exactness of discrimination.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.10
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• pp.363-372
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• 2022

Since the recent COVID-19 Pandemic, the ransomware fandom has intensified along with the expansion of remote work. Currently, anti-virus vaccine companies are trying to respond to ransomware, but traditional file signature-based static analysis can be neutralized in the face of diversification, obfuscation, variants, or the emergence of new ransomware. Various studies are being conducted for such ransomware detection, and detection studies using signature-based static analysis and behavior-based dynamic analysis can be seen as the main research type at present. In this paper, the frequency of ".text Section" Opcode and the Native API used in practice was extracted, and the association between feature information selected using K-means Clustering algorithm, Cosine Similarity, and Pearson correlation coefficient was analyzed. In addition, Through experiments to classify and detect worms among other malware types and Cerber-type ransomware, it was verified that the selected feature information was specialized in detecting specific ransomware (Cerber). As a result of combining the finally selected feature information through the above verification and applying it to machine learning and performing hyper parameter optimization, the detection rate was up to 93.3%.

• Wind and Structures
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• v.26 no.3
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• pp.179-190
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• 2018

Translation of tornadoes is an important feature in replicating the near-ground tornado flow field which has been simulated in previous studies based on Ward-type tornado simulators using relative motion of the ground plane. In this laboratory investigation, effects of translation on the near-ground tornado flow field were studied using the ISU Tornado Simulator that can physically translate over a ground plane. Two translation speeds, 0.15 m/s and 0.50 m/s, that scale up to those corresponding to slowly-moving tornadoes in the field were selected for this study. Compared with the flow field of a stationary tornado, the simulated tornado with translation had an influence on the spatial distribution and magnitude of the horizontal velocities, early reversal of the radial inflow, and expansion of the core radius. Maximum horizontal velocities were observed to occur behind the center of the translating tornado and on the right side of its mean path. An increase in translation speed, resulted in reduction of maximum horizontal velocities at all heights. Comparison of the results with previous studies that used relative motion of the ground plane for simulating translating tornadoes, showed that translation has similar effects on the flow field at smaller radial distances (~2 core radius), but different effects at larger radial distances (~4 core radius). Further, it showed that the effect of translation on velocity profiles is noticeable at and above an elevation of ~0.6 core radius, unlike those in studies based on the relative motion of the ground plane.

• Journal of Power Electronics
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• v.8 no.1
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• pp.91-100
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• 2008

The d-q harmonic detecting algorithms are dominant methods to generate current references for active power filters (APF). They are often implemented in the synchronous frame and time domain. This paper researches the frequency characteristics of d-q synchronous transformations, which are closely related to the analysis and design issues of control system. Intuitively, the synchronous transformation is explained with amplitude modulation (AM) in this paper. Then, the synchronous filter is proven to be a time-invariant and linear system, and its transfer function matrix is derived in the stationary frames. These frequency-domain models imply that the synchronous transformation has an equivalent effect of frequency transformation. It is because of this feature, the d-q method achieves band-pass characteristics with the low pass filters in the synchronous frame at run time. To simplify these analytical models, an instantaneous positive-negative sequence frame is proposed as expansion of traditional symmetrical components theory. Furthermore, the synchronous filter is compared with the traditional bind-pass filters based on these frequency-domain analytical models. The d-q harmonic detection methods are also improved to eliminate the inherent coupling effect of synchronous transformation. Typical examples are given to verify previous analysis and comparison. Simulation and experimental results are also provided for verification.

• Journal of the Korean Society for information Management
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• v.27 no.3
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• pp.227-239
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• 2010

Opinion retrieval is to retrieve items which are relevant to the user information need topically and include opinion about the topic. This paper aims to find a method to represent user information need for effective opinion retrieval and to analyze the combination methods for opinion features through various experiments. The experiments are carried out in the inference network framework using the Blogs06 collection and 100 TREC test topics. The results show that our suggested representation method based on hidden 'opinion' concept is effective, and the compact model with very small opinion lexicon shows the comparable performance to the previous model on the same test data set.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.104-112
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• 2016

The Adaboost chooses a good set of features in rounds. On each round, it chooses the optimal feature and its threshold value by minimizing the weighted error of classification. The involved process of classification performs a hard decision. In this paper, we expand the process of classification to a soft fuzzy decision. We believe this expansion could allow some flexibility to the Adaboost algorithm as well as a good performance especially when the size of a training data set is not large enough. The typical Adaboost algorithm assigns a same weight to each training datum on the first round of a training process. We propose a new algorithm to assign different initial weights based on some statistical properties of involved features. In experimental results, we assess that the proposed method shows higher performance than the traditional one.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.201-210
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• 2018

An airbag is an essential automotive component used in all kinds of vehicles such as an internal combustion engine and an electric motor vehicle and is used to minimize the damage of an occupant in the event of an accident. Airbag-related parts are being monopolized by a small number of foreign companies around the world. In this situation, it is necessary to develop and research the airbag-related part molding technology for expansion of the domestic airbag-related market and corporate export. As a part of this research, we have developed a mold for airbag inflator cap. The development consists of three steps which are the design of components, analysis of the design and verification of it. In the case of the design, the transfer type mold was designed for the multi-cylindrical shaped feature. Analysis was then conducted on the design. By examining the results of analysis, changing features and numbers of punches and dies were added in the analysis and repeatedly analyzed. After the addition, proper dimensions from the analysis were achieved, and prototypes were practically produced and verified. In the case of prototype verification, Pressurizing Burst Test was conducted on the existing products and the prototype. By comparing the results of the test, the possibility of replacing the existing product of the airbag inflator cap is presented in this paper.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.1
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• pp.67-74
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• 2016

Establishing a renewal plan and practical use of Jungam temple, which exists natural monuments, including national treasures and Gangwondo cultural materials, at Jungseon is as important as anything else. To discuss the renewal plan and the practical use of Jungam temple, this thesis is composed with the next series of processes. First, this thesis presents examining a relationship between Jajang, who was a buddhist monk and caused a departure point of foundation of the temple, and Jungam temple is necessary; thus, the relationship of his architectural consciousness and Jungam temple was showed in this thesis. Second, this thesis demonstrates present conditions for extant facilities and features of the space structure for Jungam temple to look into architectural characteristics of Jungam temple. Third, this thesis shows preservation of Jungam temple because this temple is the historic cultural resource; in addition, this thesis explains restoring of lost elements for points, repairing shipments regarding the whole area of preservation targets, expansion of the area nearby historic cultural resources to make plans for maintaining Jungam temple. Finally, this thesis concludes the final result of Jungam temple to work towards becoming the contemporarily historic cultural resource by designating Jungam temple as the historic site and suggesting energization by public participation and experience programs to continuously manage Jungam temple.