• Journal of KIISE
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• v.43 no.4
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• pp.480-488
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• 2016

Search-Based Software Testing (SBST) is an effective technique for test data generation on large domain size. Although the performance of SBST seems to be affected by the structural characteristics of Software Under Test (SUT), studies for the comparison of SBST techniques considering structural characteristics are rare. In addition to the comparison study for SBST, we analyzed the best algorithm with different structural characteristics of SUT. For the generalization of experimental results, we automatically generated 19,800 SUTs by combining four metrics, which are expected to affect the performance of SBST. According to the experiment results, Genetic algorithm showed the best performance for SUTs with high complexity and test data evaluation with count ${\leq}20,000$. On the other hand, the genetic simulated annealing and the simulated annealing showed relatively better performance for SUTs with high complexity and test data evaluation with count ${\geq}50,000$. Genetic simulated annealing, simulated annealing and hill climbing showed better performance for SUTs with low complexity.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.399-408
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• 2001

Tooth bleaching has been prevailing recently for its ability to recover the color and shape of natural teeth without reduction of tooth material. However, it has been reported that bleaching procedure adversely affects the adhesive bond strength of composite resin to tooth. At the same time the bond strength was reported to be regained by application of some chemical agents. The purpose of this in vitro study was to investigate the effect of the removal of residual peroxide on the composite- enamel adhesion and also evaluated fracture mode between resin and enamel after bleaching. Sixty extracted human anterior and premolars teeth were divided into 5 groups and bleached by combined technique using of office bleaching with 35 % hydrogen peroxide and matrix bleaching with 10% carbamide peroxide for 4 weeks. After bleaching, the labial surfaces of each tooth were treated with catalase, 70% ethyl alcohol, distilled water and filled with composite resin. Shear bond strength was tested and the fractured surfaces were also examined with SEM. Analysis revealed significantly higher bond strength values. (p＜0.05) for catalase-treated specimens, but water-treated specimens showed reduction of bond strength, alcohol- treated specimens had medium value between the two groups(p＜0.05). The fracture mode was shown that the catalase group and the alcohol group had cohesive failure but the water sprayed group had adhesive failure. It was concluded that the peroxide residues in tooth after bleaching seems to be removed by gradual diffusion and the free radical oxygen from peroxide prevents polymerization by combining catalyst in the resin monomer. Therefore it may be possible to eliminate the adverse effect on the adhesion of composite resin to enamel after bleaching by using water displacement solution or dentin bonding agent including it for effective removal of residual peroxide.

• Korean Journal of Optics and Photonics
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• v.16 no.6
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• pp.500-507
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• 2005

Two-dimensional (2D) images that are produced by terahertz (THz) irradiation we presented. It is possible to obtain 2D image of various materials by observing the amplitude and the phase of the THz signals which go through them. Better images are produced by combining the amplitude and phase of the signal rather than using only one of these. Homomorphic filtering that is one elf the well-known technique of digital image signal processing is effective to reduce the noise signal and can provide better quality images. The results can be applied to real-time imaging afterwards.

• Nuclear Engineering and Technology
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• v.16 no.1
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• pp.36-46
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• 1984

Studied are the statistical thermal design (STD) methods that have been developed to satisfy the design basis which protects a pressurized water reactor (PWR) core against departure from nucleate boiling (DNB) during normal operations and anticipated transients. The objective of the statistical thermal design is to quantify the thermal design margin and to remove any excess conservatism from the DNB ratio calculations through statistically combining design parameter uncertainties, while still maintaining a high level of core protection. This report describes and compares the STD methods developed by the two U.S. reactor vendors (Westinghouse and B & W). Included are the characteristics of STD, statistical treatment of uncertainties, DNB design limit development methodology and the sample application of the STD technique to core thermal design analysis. It is observed that the STD methods developed by the two vendors are similiar to each other in principle, but different in the treatment of the uncertainties associated with the design parameters. The statistical thermal design is found to significantly improve the thermal design margin.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.89-97
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• 2002

We have developed the 45-Van system in order to maximize the interoperability of spatial data in 45(GNSS, SIIS, GIS, ITS) by sharing and providing spatial data of remote site. The 4S-Van system enables to acquisition and production of information for GIS database and the accurate position information by combining and connecting GPS/IMU, laser, CCD(charged-coupled device) image, and wireless telecommunication technology. That is, 4S-Van system measures its position and attitude using integrated GPS/IMU and takes two photographs of the front scene by two CCD cameras, analyzes position of objects by space intersection method, and constructs database that has compatibility with existing vector database system. Furthermore, infrared camera and wireless communication technique can be applied to the 4S-Van for a variety of applications. In this paper, we discuss the design and functions of 4S-Van that is equipped with GPS, CCD camera, and IMU.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.16-22
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• 2020

Since it is difficult for individual power producers and non-professionals who lack basic knowledge to control, manage, and operate facilities through EMS (Energy Management System), augmented reality and virtual reality monitoring systems are applied. However, in the existing systems, data access efficiency is inferior due to the process of analyzing column values for analog signal values collected from sensors and converting data after combining the columns. In addition, high-speed operation processing is difficult due to a large number of indexes for accommodating access patterns for various analog signal waveforms. Therefore, in this paper, a bitmap generator is inserted into a non-tree structure to convert the data collected from power facilities into physical property information, and the converted information is encrypted with a common key, so that the resources for the resources shared between each device are We propose a method of exchanging data for an augmented reality-based power system that is controlled by measurement.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.17-27
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• 2020

News articles and blog posts have influence on social agenda setting and this study applied text mining on the subject of solar PV in rural area appeared in those media. Texts are gained from online news articles and blog posts with rural solar PV as a keyword by web scrapping, and these are analysed by sentiment analysis and topic modeling technique. Sentiment analysis shows that the proportion of negative texts are significantly lower in blog posts compared to news articles. Result of topic modeling shows that topics related to government policy have the largest loading in positive articles whereas various topics are relatively evenly distributed in negative articles. For blog posts, topics related to rural area installation and environmental damage are have the largest loading in positive and negative texts, respectively. This research reveals issues related to rural solar PV by combining sentiment analysis and topic modeling that were separately applied in previous studies.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.63-74
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• 2005

In Electronic Commerce, the latest most of the personalized recommender systems have applied to the collaborative filtering technique. This method calculates the weight of similarity among users who have a similar preference degree in order to predict and recommend the item which hits to propensity of users. In this case, we commonly use Pearson Correlation Coefficient. However, this method is feasible to calculate a correlation if only there are the items that two users evaluated a preference degree in common. Accordingly, the accuracy of prediction falls. The weight of similarity can affect not only the case which predicts the item which hits to propensity of users, but also the performance of the personalized recommender system. In this study, we verify the improvement of the prediction accuracy through an experiment after observing the rule of the weight of similarity applying Vector similarity, Entropy, Inverse user frequency, and Default voting of Information Retrieval field. The result shows that the method combining the weight of similarity using the Entropy with Default voting got the most efficient performance.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.545-554
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• 2004

Combining multiple classifiers to obtain improved performance over the individual classifier has been a widely used technique. The task of constructing a multiple classifier system(MCS) contains two different Issues how to generate a diverse set of base-level classifiers and how to combine their predictions. In this paper, we review the characteristics of existing multiple classifier systems : Bagging, Boosting, and Slaking. For document classification, we propose new MCSs such as Stacked Bagging, Stacked Boosting, Bagged Stacking, Boosted Stacking. These MCSs are a sort of hybrid MCSs that combine advantages of existing MCSs such as Bugging, Boosting, and Stacking. We conducted some experiments of document classification to evaluate the performances of the proposed schemes on MEDLINE, Usenet news, and Web document collections. The result of experiments demonstrate the superiority of our hybrid MCSs over the existing ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1181-1185
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• 2005

A combining of MIMO signal processing with OFDM is regarded as a promising solution of enhancing the performance of next generation wireless system. Therefore, in this paper, an OFDM-based wireless system employing layered space-time architecture is considered for a high-rate transmission. In the MIMO-OFDM system, we evaluate the PAR performance using the SLM approaches. The investigated SLM scheme for MIMO-OFDM signals selects the transmitted sequence with lowest average PAR over all transmitting antennas and retrieves the side information very accurately at the expense of a slight degradation of the PAR performance. The low probability of false side information can improve the overall detection performance of the MIMO-OFDM system with erroneous side information compared to the ordinary SLM approache, respectively. Also, we provide closed form of the average BER performance in MIMO-OFDM system using analytic approach.