• KIPS Transactions on Computer and Communication Systems
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• v.7 no.3
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• pp.67-72
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• 2018

Recently, noise reduction in an axial fan producing the small pressure rise and large flow rate, which is one type of turbomachine, is recognized as essential. This study describes the design and optimization techniques of MPI parallel program to simulate the flow-induced noise in the axial fan. In order to simulate the code using 100 million number of grids for flow and 70,000 points for noise sources, we parallelize it using the 2D domain decomposition. However, when it is involved many computing cores, it is getting slower because of MPI communication overhead among nodes, especially for the noise simulation. Thus, it is adopted the one-sided communication to reduce the overhead of MPI communication. Moreover, the allocated memory and communication between cores are optimized, thereby improving 2.97x compared to the original one. Finally, it is achieved 12x and 6x faster using 6,144 and 128 computing cores of KISTI Tachyon2 than using 256 and 16 computing cores for the flow and noise simulations, respectively.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.32-39
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• 2009

In this paper, the method of region segmentation using genetic algorithm is proposed for an improvement of efficiency in moving picture coding. A genetic algorithm is the method that searches a large probing space using only a function value for a optimal combination consecutively. By progressing both motion presumption and region segmentation at once, we can assign the motion vector in a image to a small block or a pixel respectively, and transform the capacity of coding and a signal to noise rate into a problem of optimization. That is to say, there is close correlation between region segmentation and motion presumption in motion-compensated prediction coding. This is to optimize the capacity of coding and a S/N ratio. This is to arrange the motion vector in each block of picture according to the state of optimization. Therefore, we examined both the data type of genetic algorithm and the method of data processing to obtain the results of optimal region segmentation in this paper. And we confirmed the validity of a proposed method using the test pictures by means of computer simulation.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.2
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• pp.73-86
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• 2016

The purpose of this study is to examine a security investment for firms experienced in confidential information leak. Information security is an apparatus for protection of secret information. The competence of information security is a competitiveness to avoid information leakage in changing business environment. The type of information security is divided into administrative security, technical security and physical security. It is necessary to improve the incident correspondence competence through information security investment of the three types. Therefore, the investment of information security is to enhance information-asset protection of firms. To reinforce accident response competence, an organization discussed an establishment, security technology development, expand investment and legal system of the security system. I have studied empirically targeting the only information leak of firms. This data is a technical security competence and technology leakage situation of firms happened in 2010. During recovery of the DDos virus damage on countries, company and individual, the collected data signify a reality of information security. The data also identify a security competence of firms worrying information security management. According to the study, the continuous investment of information security has a high competence of accident correspondence. In addition, the most of security accidents showed a copy and stealing of paper and computer files. Firm on appropriate security investment is an accident correspondence competence higher than no security investment regardless of a large, small and medium-sized, and venture firm. Furthermore, the rational security investment should choose the three security type consideration for firm size.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.823-829
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• 1986

The Large-scale structure of the circular jet in the transition region, which influences the subsequent flow in the turbulent region, was studied experimentally. Measuring equipments are composed of the two channel hot-wire anemometer, the computer controlled two-directional traverse mechanism, the data acquisition system, and FFT-analyzer. The circular jet has 50mm diameter. The mean velocity distribution, the velocity fluctuation, the auto 'cross correlations and the power spectra were acquired at moderate Reynolds number of 10$^{4}$. And the VITA method was used to measure the convection velocity of Large-scale eddy. The phase of u'is in advance of that of v'in all regions. .over bar. $R_{u}$(.tau.=0) is approximately zero in the potential core region, but a small regular deviation is observed. At a position in the mixing layer region the convection velocity is different along the part of the eddy, and in this experiment the convection velocity of the inner region is larger than the outer region. The averge convection velocity of the eddy along y/D=0 was approximately constant in the transition region.D=0 was approximately constant in the transition region.

• Journal of Korean Society for Quality Management
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• v.17 no.1
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• pp.69-81
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• 1989

This study is concerned with a job sequencing method using the concept of sampling technique in the case of Job Shop. This is the follow study of Kang and Ro (1988) which examined the possibility of application of sampling technique to determine the Job Sequence in the case of Flow Shop. Not only it is very difficult, but also it takes too much time to develop the appropriate job schedules that satisfy the complex work conditions. The most job sequencing algorithms have been developed to determine the best or good solution under the special conditions or assumptions. The application areas of these algorithms are also very narrow, so it is very hard to find the appropriate algorithm which satisfy the complex work conditions. In this case it is very desirable to develop a simple job sequencing method which can select the optimal job sequence or near optimal job sequence with a little effort. This study is to examine the effect of sampling job sequencing which can select the good job of 0.01%~5% upper good group. The result shows that there is the sets of 0.05%~23% job sequence group which has the same amount of performance measure with the optimal job sequence in the case of experiment of N/M/G/$F_{max}$. This indicates that the sampling job sequencing method is a useful job sequencing method to find the optimal or good job sequence with consuming a small amount of time. The results of ANOVA show that the only one factor, number of machines is the significant factor for determining the job sequence at ${\alpha}=0.01$. It takes about 10 minutes to compare the number of 10,000 samples of job sequence by personal computer and it is proved that the selection rate of the same job sequence with optimal job sequence is 23.0%, 3.9% and 0.065% in the case of 2 machines, 3 machines and 4 machines, respectively. The area of application can readily be extended to the other work condition.

• Journal of Engineering Education Research
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• v.5 no.1
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• pp.68-76
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• 2002

It is proposed to raise the debate on Engineering and Technical Education at the global economic level and to examine some of the issues facing developing and poorer countries in managing and improving the quality of engineering education in their countries, especially in the context of internet and IT culture After the fall of the Berlin Wall, the world is now divided in two realigned blocks: one of developed(rich or advanced) countries which have a social security safety net for their population and another of developing(or poor) countries which have no such luxuries for their population. For the general public in the developing countries, any engineering or technical degree/diploma is a passport to lifelong wellbeing of an individual and his/her extended family. Therefore, the demand for such qualifications is very high and it is almost a rat race amongst school leavers to get into engineering/technical colleges. In view of this booming demand, there are hundreds of privately funded engineering/technical colleges in countries like Philippines, India, Thailand, etc., besides state funded ones. It is extremely difficult to ensure good quality in this mushrooming scenario. There are also many very small poorly resourced developing countries where there is only one engineering school and/or two-three technical colleges. Products of these schools/colleges work only in their own country and education globalization have little or no meaning for them. Besides highlighting the aforementioned general issues, the Paper also presents a few case studies on problems of accreditation and quality assessment in larger developing countries like India and the Philippines. The Paper also discusses the effects of commercialization on the quality of education and social impacts of IT revolution on educational processes.

• Journal of Fashion Business
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• v.2 no.3
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• pp.98-108
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• 1998

The purpose of this study is to provide for the basic data useful to the effective production and marketing of the foundation garments befitting adult women's body shapes and preferences, and thereby, help them improve their apparel life. For this purpose, 563 Korean adult women aged between 20-59 were sampled to survey their recognition and actual wearing condition of foundation garments and positively identify the factors affecting the practices and thereupon, determine the correlations among them by age group. Data is processed by a computer (SAS) and analyzed by using frequency, percentage, ${\chi}^2$-test, ANOVA, Duncan-test. The main results of this study are as follows; 1. The most of the adult women were aware of the basic underwear terminologies and the absolute majority of them wore brassieres, while a half of them used the girdles. In contrast, only a small portion of them wore body suites or waste-nippers and the absolute minority of them had garterbelts. 2. The use of the foundations depended much on users' ages or seasons. They had begun to wear brassieres and girdles at their age of 15 on average, and bodysuites, waist-nippers or garterbelts around their age of 20 depending on their individual needs. 3. The adult women had 3-6 brassieres and 2-3 girdles on average, but only a minority of them owned one or two body suites, waist-nippers or garterbelts. They had ever used the functional foundations (11.5%) or imported foundations (35.9%), It has been found through this study that adult women's recognition and actual wearing condition of their foundation garments differ by age group, which may well suggest that foundation production need to take such age-wise practices into consideration in setting up their foundation production and marketing strategies.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.2
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• pp.42-46
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• 2018

Adaptive signal processing is quite important in various signal and communication environments. In adaptive signal processing methods since the least mean square(LMS) algorithm is simple and robust, it is used everywhere. As the step is varied in the variable step(VS) LMS algorithm, the fast convergence speed and the small excess mean square error can be obtained. Various variable step LMS algorithms are researched for better performances. But in some of variable step LMS algorithms the computational complexity is quite large for better performances. The fixed step LMS algorithm with a low computational complexity merit and the variable step LMS algorithm with a fast convergence merit are combined in the proposed sporadic step algorithm. As the step is sporadically updated, the performances of the variable step LMS algorithm can be maintained in the low update rate using Fibonacci sequence. The performances of the proposed variable step LMS algorithm are proved in the adaptive equalizer.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.52-61
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• 2006

A crossword puzzle is one of the popular word games around the world in which you work out the answers and write them in the white squares of a pattern of small black and white squares. As the technology of computers develops, some people worked about making and solving crossword puzzle games, which led them to a commercial use. However, almost all of these commercial programs are ones where you do ready-made puzzles with a fixed size because it is very difficult to make puzzles in a certain size, picking up some among a great number of words to fit for them. Furthermore, these programs are only for a very few languages, such as English, French, not for Korean. Accordingly, ore took a look at what should be considered to make an automatic puzzle-generating program for Korean, and in this paper we implemented Korizzle, a system making the puzzles automatically. We introduce the algorithm used for Korizzle and evaluate the its performance.

• Journal of Korea Game Society
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• v.10 no.1
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• pp.147-156
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• 2010

In this paper, we propose 3D cloud animation by cloud modeling method of 2D images retrieved from a meteorological satellite. First, on the satellite images, we locate numerous control points to perform thin-plate spline warping analysis between consecutive frames for the modeling of cloud motion. In addition, the spectrum channels of visible and infrared wavelengths are used to determine the amount and altitude of clouds for 3D cloud image reconstruction. Pre-integrated volume rendering method is used to achieve seamless inter-laminar shades in real-time using small number of slices of the volume data. The proposed method could successfully construct continuously moving 3D clouds from 2D satellite images at an acceptable speed and image quality.