• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.26-28
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• 2007

The motion estimation is the most important technique in the image compression of the video standards. In the case of next generation standards in the video codec as H.264, a high compression-efficiency can be also obtained by using a motion compensation. To obtain the accurate motion search, a motion estimation should be achieved up to 1/2 pixel and 1/4 pixel uiuts. To do this, the computational complexity is increased although the image compression rate is increased. Therefore, in this paper, we propose the advanced sub-pixel block matching algorithm to reduce the computational complexity by using a statistical characteristics of SAD(Sum of Absolute Difference). Generally, the probability of the minimum SAD values is high when searching point is in the distance 1 from the reference point. Thus, we reduced the searching area and then we can overcome the computational complexity problem. The main concept of proposed algorithm, which based on TSS(Three Step Search) method, first we find three minimum SAD points which is in integer distance unit, and then, in second step, the optimal point is in 1/2 pixel unit either between the most minimum SAD value point and the second minimum SAD point or between the most minimum SAD value point and the third minimum SAD point In third step, after finding the smallest SAD value between two SAD values on 1/2 pixel unit, the final optimized point is between the most minimum SAD value and the result value of the third step, in 1/2 pixel unit i.e., 1/4 pixel unit in totally. The conventional TSS method needs an eight.. search points in the sub-pixel steps in 1/2 pixel unit and also an eight search points in 1/4 pixel, to detect the optimal point. However, in proposed algorithm, only total five search points are needed. In the result. 23 % improvement of processing speed is obtained.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.4
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• pp.85-95
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• 2014

In the e-commerce, the conversion into the multi-media is the important issue. According to the research by Nielsen Korea, the 83% of customers who purchase the products in the e-commerce utilize multi-channel to buy the products such as mobile and online [3]. Thus, to effectively implement online advertising, marketers should understand the customers' path [15] in the multi-channel. The study of the multi-site activities plays an important role to predict customers' purchase [28]. To explain the e-commerce site visit activities of customers, we have developed research model in terms of the online advertising. This research model is based on the study of Moe and Fader [23]. There are two types of composition in the research model. First, general site visit as an exploratory search have net effect on the shopping site visit because customers could acquire or develop information on the e-commerce site via online advertising. Secondly, the e-commerce site visit as a goal-directed search cause threshold of the e-commerce site visit because customers could achieve their goal. When the threshold is increased, the probability of a shopping site visit is decreased and vice versa. Thus, we have investigated the impact of customers' previous visit activities (general site visit and shopping site visit) on the next e-commerce site visit in terms of dynamic view. Research data was provided by Cheil World Wide. This panel data include mobile and online log data of panelists from Jan. 2013 to March 2013. As the results, the customers' e-commerce site visit on the online media would decrease the probability of e-commerce site visit because these visit activities increase the threshold of e-commerce site visit. This result is similar with the previous study [23]. Otherwise, since e-commerce site visit on the mobile media decrease the threshold, the customers' probability of e-commerce site visit would increase In summary, the site visit activities on the mobile could improve the probability of e-commerce site visits.

• The Mathematical Education
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• v.42 no.2
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• pp.203-218
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• 2003

The purpose of this study is to see what the essential characteristics are in teaching probability and statistics among various mathematical fields. we also tried to connect the study of probability and statistics education with what is needed for a science be synthetic to have its own identity as a unique research field. Since we searched for the future direction of the pedagogic study in the probability and statistics we first selected papers on probability and statistics published in (Series A), the Journal of Korea Society of Mathematical Education, and establish the following research questions. What kinds of characteristics can be found when papers on probability and statistics published in (Series A) are classified into low categories; contents of probability and statistics education, research method of the mathematics education, methods of teaming and teaching, and finally measurements and evaluation\ulcorner We classified papers into two kinds. One is related to the educational contents, consisting of the methods of learning and teaching, and of the measurement and evaluation. The other is reined to the methods of research, which is not a part of the educational curriculum but is essential for establishing the identity of mathematics education. According to the periods, papers on the curricular contents in 1960s were influenced by the New Mathematics, and papers on the curricular contents in 1980s were influenced by 'back to basic'. In 1990s, papers on methods of learning and teaching, and measurement md evaluation were increasing in number. Besides, (series A) from the Journal of Korea Society of Mathematical Education covers contents, methods of Loaming and teaching, and measurement and evaluation. And when I examined the papers on the contents of textbook of a junior high school related to the probability and statistics education and on methods of learning and teaching, 1 found that those papers occupy 1.84% in . When it comes to the methods of loaming and teaching, most of studies in (series A) are about application of concrete implement like experiment and practical application of computer programs, Through this study, I found that over-all and more active researches on probability and statistics are required and that the studies about methods of loaming and teaching must be made in diverse directions. It is needed that how students recognize probability and statistics, connection, communication and representation in probability and statistics context, too. (series A) does not have papers on methods of study. Mathematics pedagogy is a mixture of various studies - mathematical psychology, mathematical philosophy, the history of mathematics and Mathematics. So If there doesn't exist a proper method of study adequate in the situation for the mathematics education the issue of mathematics pedagogy might be taken its own place by that of other studies'. We must search for the unique method of study fur mathematics education so that mathematics pedagogy has its own identity as a study. The study concerning this aspect is needed.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.3
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• pp.77-90
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• 2018

Software Defect Prediction (SDP) is a field of study that identifies defective modules. With insufficient local data, a company can exploit Cross-Project Defect Prediction (CPDP), a way to build a classifier using dataset collected from other companies. Most machine learning algorithms for SDP have used more than one parameter that significantly affects prediction performance depending on different values. The objective of this study is to propose a parameter selection technique to enhance the performance of CPDP. Using a Harmony Search algorithm (HS), our approach tunes parameters of cost-sensitive boosting, a method to tackle class imbalance causing the difficulty of prediction. According to distributional characteristics, parameter ranges and constraint rules between parameters are defined and applied to HS. The proposed approach is compared with three CPDP methods and a Within-Project Defect Prediction (WPDP) method over fifteen target projects. The experimental results indicate that the proposed model outperforms the other CPDP methods in the context of class imbalance. Unlike the previous researches showing high probability of false alarm or low probability of detection, our approach provides acceptable high PD and low PF while providing high overall performance. It also provides similar performance compared with WPDP.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.45-51
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• 2011

This paper proposes a method to accelerate the evolution speed of individuals through hybrid reproduction of monogenesis and gamogenesis. Monogenesis as a reproduction method that bacteria or monad without sexual distinction divide into two individuals has an advantage for local search and gamogenesis as a reproduction method that individuals with sexual distinction mate and breed the offsprings has an advantages for keeping the diversity of individuals. These properties can be properly used for improvement of evolution speed of individuals in genetic algorithms. In this paper, we made relatively good individuals among selected parents to do monogenesis for local search and forced relatively bad individuals among selected parents to do gamogenesis for global search by increasing the diversity of chromosomes. The mutation probability for monogenesis was set to a lower value than that of original genetic algorithm for local search and the mutation probability for gamogenesis was set to a higher value than that of original genetic algorithm for global search. Experimental results with four function optimization problems showed that the performances of three functions were very good, but the performances of fourth function with distributed global optima were not good. This was because distributed global optima prevented individuals from steady evolution.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.4
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• pp.1-10
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• 2001

The 3-step cell search has been considered for fast acquisition of the scrambling code unique to a cell in the W -CDMA system. In this paper, the performance of the cell search scheme is analyzed in Rayleigh fading channels. And the system parameters for cell search scheme and the design parameters for the receivers are examined. The probabilities of detection, miss and false alarm for each step are derived in closed forms based on the statistics of CDMA noncoherent demodulator output. Through the analysis, the effect of threshold setting and post detection integration for each step is investigated, and the optimal values of the power allocation for the synchronization channels are also considered. The number of post-detection integrations for each step is a design parameter for the receiver, and the optimum values may depend on not only the power allocation for each channel related to the cell search, but the false alarm penalty time. It is shown that optimal values could be determined through the analysis. Also, the cumulative probability distribution of the average cell search time is obtained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.782-791
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• 2013

This paper proposes the location estimation techniques of distributed targets with the multi-sensor data perceived through IR sensors of the military robots. In order to match up targets with measured azimuths, we apply the maximum likelihood (ML), depth-first, and breadth-first tree search algorithms, in which we use the measured azimuths and the number of pixels on IR screen for pruning branches and selecting candidates. After matching up targets with azimuths, we estimate the coordinate of each target by obtaining the intersection point of the azimuths with the least square error (LSE) algorithm. The experimental results show the probability of missing target, mean of the number of calculating nodes, and mean error of the estimated coordinates of the proposed algorithms.

• Structural Engineering and Mechanics
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• v.60 no.3
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• pp.413-431
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• 2016

A sensitivity analysis estimates the effect of the change in the uncertain variable parameter on the probability of the structural failure. A novel fuzzy random reliability sensitivity measure of the failure probability is proposed to consider the effect of the epistemic and aleatory uncertainties. The uncertainties of the engineering variables are modeled as fuzzy random variables. Fuzzy quantities are treated using the ${\lambda}$-cut approach. In fact, the fuzzy variables are transformed into the interval variables using the ${\lambda}$-cut approach. Genetic approach considers different possible combinations within the search domain (${\lambda}$-cut) and calculates the parameter sensitivities for each of the combinations.

• Journal of the Korea Computer Industry Society
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• v.4 no.4
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• pp.523-532
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• 2003

In this paper, we designed a 128-bit block cipher, Lambda, which has 16-round extended Feistel structure and analyzed its secureness by the differential cryptanalysis and linear cryptanalysis. We could have full diffusion effect from the two rounds of the Lambda. Because of the strong diffusion effect of the algorithm, we could get a 8-round differential characteristic with probability $2^{-192}$ and a linear characteristic with probability $2^{-128}$. For the Lambda with 128-bit key, there is no shortcut attack, which is more efficient than the exhaustive key search, for more than 8 rounds of the algorithm.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.8
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• pp.11-18
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• 1993

In a spread spectrum system, the bandwidth and period of spreading code is wide and long, respectively. So it is necessary to make the code acquisition time as short as possible. In particular, serial search code acquisition system requires optimum dwell time for fast acquisition. In this paper, code acquisition time is calculated by varying dwell time. Among them, minimum code acquisition time is chosen and then optimum dwell time can be obtained. Detection probability (P$_{D}$) and false alarm probability (P$_{FA}$) can be obtained by integrating chi-square pdf by numerical analysis. The results are compared with that of gaussian approximation method and then it is concluded gaussian approximation method is not suitable for obtaining optimum dwell time. Computer simulation supports theoretical results.