• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.292-296
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• 2004

본 논문에서는 컬러영상에서 Pulse-Coupled Neural Network를 이용한 얼굴 추출 알고리즘의 성능을 향상시키는 방법에 대하여 논의하였다. 색상정보를 이용한 얼굴 추출 알고리즘은 얼굴의 기울어진 정도나 크기 둥에 영향을 받지 않으므로, 형태정보를 이용한 얼굴 추출 알고리즘에 비해 비교우위를 가진다. 그러나 조명의 변화가 심하거나, 피부색과 유사한 배경이 포함되어 있을 경우 적절한 성능을 내기 어렵다. 이러한 문제점들을 해결하기 위해 본 연구에서는 넓은 피부색 영역을 추출하고, Pulse-Coupled Neural Network를 통해 공간적으로 근접한 피부색 동종영역을 분리해 내는 방법을 사용하였다. 그리고 피부색 영역에 해당하는 픽셀들이 다른 영역들에 비해 큰 값을 갖도록 하여, Pulse-Coupled Neural Network의 linking coefficient를 보다 쉽게 결정하도록 하였다.

• Elastomers and Composites
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• v.25 no.2
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• pp.112-116
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• 1990

In this study, as one way of developing the new cross-linking method that is curable in water, kinetic analysis of solution reaction between CR and silane coupling agents was attemped. First, CR was reacted with silane coupling agents in solution state. According to the time, reaction quantity was pursued by gas chromatography. Also, reaction rate coefficient and activation energy were calculated from the reaction quantity. Silane coupling agents which were used in this study were MPS, CPS and VES.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.153-153
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• 2016

Polyoxymethylene copolymer (POM-C) is an attractive and widely used engineering thermoplastic across many industrial sectors owing to outstanding physical, mechanical, self-lubricating and chemical properties. In this research work, the POM-C blocks were irradiated with 1 MeV electron beam energy in five doses (100, 200, 300, 500 and 700 KGy) in vacuum condition at room temperature. The tribological and physico-chemical properties of electron beam irradiated POM-C blocks have been analyzed using Pin on disk tribometer, Raman spectroscopy, SEM-EDS, Optical microscopy, 3D Nano surface profiler system and Contact angle analyzer. Electron beam irradiation at a dose of 100 kGy resulted in a decrease of the friction coefficient and wear loss of POM-C block due to well suited cross-linking, carbonization, free radicals formation and energetic electrons-atoms collisions (physical interaction). It also shows lowest surface roughness and highest water contact angle among all unirradiated and irradiated POM-C blocks. The irradiation doses at 200, 300, 500 and 700 kGy resulted in increase of the friction coefficient as compared to unirradiated POM-C block due to severe chain scission, chemical and physical structural degradation. The electron beam irradiation transferred the wear of unirradiated POM-C block from the abrasive wear, adhesive wear and scraping to mild scraping for the 1 MeV, 100 kGy irradiated POM-C block which is concluded from SEM-EDS and Optical microscopic observations. The degree of improvement for tribological attribute relies on the electron beam irradiation condition (energy and dose rate).

• Journal of Korean Academy of Nursing
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• v.25 no.1
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• pp.141-155
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• 1995

The objective of this study was to develop a scale to measure stress in infertile couples and to test its reliability and validity. Prior to item generation, a basic decision was made to conceptualize stress in infertile couples as including two dimensions and four subdimensions. The dimensions were, intrapersonal stress including cognitive and affective stress, and interpersonal stress including marital and social stress. Initially 95 items were generated from the inter-view data of 31 primary or secondary infertile women and from a literature review. These items were analyzed through the Index of Content Validity(CVI) and 69 items were selected which met 70% or more of the CVI. This preliminary Infertility Stress Scale were analyzed for reliability and construct validity. Item analysis and factor analysis were applied for construct validity. Forty items were selected through item analysis. This procedure was based on the inter-item correlation matrix, a corrected average inter-item correlation coefficient(.30~.70), a corrected item to total correlation coefficient (.03 or more) and information about the alpha estimate if this item was dropped from the scale. The result of the initial factor analysis including varimax rotation produced eight factors. Five items deleted because of factor complexity(indiscriminate factor loadings). The secondary factor analysis including varimax rotation produced seven factors that coincided with the conceptual framework posed for the scale developed. The seven factors were labeled as ‘meaning of children’,‘worthiness’,‘tenacious linking’,‘marital satisfaction’,‘sexual satisfaction’,‘familial adjustment’ and ‘social adjustment’. The alpha coefficient relating to internal consistency was .93 for reliability The results of this study suggest that the measurement derived from the Infertility Stress Scale is useful in assessing the stress of infertile couples.

• Journal of the Korean Society for information Management
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• v.26 no.3
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• pp.7-24
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• 2009

Since the Web is dynamic, it is necessary to analyze scholarly Web space with both quantitative and qualitative methods for better understanding of communication characteristics. In this study, we analyzed contents of pages and links to ascertain the characteristics of Korean scholarly Web space in terms of network structure and communication behavior. The result shows that the structure of the original network with all the external links remained is not much different from that of the network with activated external links only. However, the purposes of linking vary among scholarly institutions. The centrality measures correlate more strongly with the clustering coefficient than with the constraint index implying the similar explanatory power of the two types of structural indices.

• Structural Engineering and Mechanics
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• v.49 no.3
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• pp.311-327
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• 2014

The safety relating to leakage of water and pitch instability of ship chambers of the full balanced hoist vertical shiplifts has been the focus of adoption of the type of vertical shiplifts. This paper aims to remove the doubts through theoretical and engineering researches. The leakage and pitch stability of ship chambers of full balanced hoist vertical ship lifts are investigated on the basis of theoretical analysis and exploration of engineering measures. Regarding the issue of leakage of ship chambers, a mathematical model on leaking process is built and corresponding formula and coping measures are obtained which can be applied in control program of ship lifts by linking with monitoring. The concept of safety grade is put forward to seek the best technical and economic index and the corresponding technical measures are for different grades of ship lift is suggested. For the issue of pitch instability, a methodology of combining theoretical deduction and summary of achievements of design and operation of the type of the full balanced hoist shiplifts is adopted, and the formula for design about pitch stability of ship chambers is derived.

• Journal of Korean Society for Quality Management
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• v.44 no.4
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• pp.951-963
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• 2016

Purpose: This study was conducted to analyze the potential customer's satisfaction for the concepts of smart audio features and utilize the results when developing the customer-oriented products. Methods: 16 different features were derived via the market research and professionals' interviews. The most satisfactory features were selected through "Kano model", the relative importance of Customer Satisfaction Coefficient, and respondents' preferences from 339 valid survey answers. Results: 15 out of the 16 features were categorized as attractive attribute. "'User Recognizing' and 'Strengthen Linking' groups", such as Auto connection with Smart-phone music player, Synchronization of TV & Audio, and Volume control situational awareness, were shown to provide higher satisfactions to those potential customers. On the other hand, Group 'Integrating Function', such as Aromatherapy and Auto lighting reaction, was shown to be relatively least preferred features. Conclusion: This study enabled which features could lead to the customer satisfaction. Nevertheless, it still requires extensive analyses in different countries and diverse cultures to target the global market. The audio product planners and R&D professionals are expected to learn useful information from such studies.

• Geomechanics and Engineering
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• v.25 no.1
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• pp.49-58
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• 2021

The resistance of soil to the tractive force of flowing water is one of the essential parameters for the stability of the soil when directly exposed to the movement of water such as in rivers and ocean beds. Biopolymers, which are new to sustainable geotechnical engineering practices, are known to enhance the mechanical properties of soil. This study addresses the surface erosion resistance of river-sand treated with several biopolymers that originated from micro-organisms, plants, and dairy products. We used a state-of-the-art erosion function apparatus with P-wave reflection monitoring. Experimental results have shown that biopolymers significantly improve the erosion resistance of soil surfaces. Specifically, the critical shear stress (i.e., the minimum shear stress needed to detach individual soil grains) of biopolymer-treated soils increased by 2 to 500 times. The erodibility coefficient (i.e., the rate of increase in erodibility as the shear stress increases) decreased following biopolymer treatment from 1 × 10-2 to 1 × 10-6 times compared to that of untreated river-sands. The scour prediction calculated using the SRICOS-EFA program has shown that a height of 14 m of an untreated surface is eroded during the ten years flow of the Nakdong River, while biopolymer treatment reduced this height to less than 2.5 m. The result of this study has demonstrated the possibility of cross-linked biopolymers for river-bed stabilization agents.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.1-8
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• 2006

The objective of this study is to assess impacts of sorption heterogeneity on the transport of leachate leaked from unlined landfill sites and is accomplished by examining the results from a series of Monte-Carlo simulations. For random distribution coefficient ($K_{d}$) fields with four different levels of heterogeneity ranging from homogeneous to highly heterogeneous, the transport of leachate was investigated by linking a saturated flow model with a contaminant transport model. Impacts of a chemical heterogeneity were evaluated using point statistics values such as mean, standard deviation, and coefficient of variation of the concentration obtained at monitoring wells from 100 Monte-Carlo trials. Inspection of point statistics shows that the distribution of distribution coefficient in the landfill site proves to be an important parameter in controlling leachate concentrations. In comparison to homogeneous sorption, heterogeneous $K_{d^-}$ fields produce the variability in the leachate concentration for different realizations. The variability increases significantly as the variance in the $K_{d^-}$ field and the travel time between source and monitoring well increase. These outcomes indicate that use of a constant homogeneous $K_{d}$ value for predicting the transport of leachate can result in significant error, especially when variability in $K_{d}$ is high.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.503-511
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• 2007

Heart rate variability(HRV) is the clinical consequence of various influences of the autonomic nervous system(ANS) on heart beat. HRV can estimate the potential physiologic rhythm from the interval between consecutive beats(RR interval or HRV data), but cardiovascular system governed by ANS is in relation to respiration and autonomic regulation. It is known as RSA representing respiration-related HR rhythmic oscillation. Because the mechanism linking the variability of HR to respiration is complex, it has so far been unknown well. In this paper, we tried to evaluate 5-min RR interval segments under control of respiration in order to find out a proper respiration rate that can estimate the ANS function. 10 healthy volunteers were included to evaluate 5-min HRV data under 4 different respiration-controlled environments; 0.03Hz, 0.1Hz, 0.2Hz, and 0.4Hz respiration. HRV data were analyzed both in the frequency and the time domain, with cross-correlation coefficient(cross-coeff.) for HRV and respiration signal. The results showed maximum cross-coeff. of 0.84 at 0.1 Hz and minimum that of 0.16 at 0.4Hz respiration. Cross-coeff was decreased at a faster rate from 0.1Hz respiration. All mean SDNN, RMSSD, and pNN50 of time domain measures were 108.7ms, 71.85ms, and 28.47%, respectively, and LF, HF, and TP of frequency domain measures were $12,722ms^2,\;658.8ms^2$, and $7,836.64ms^2$ at 0.1Hz respiration, respectively. In conclusion, 0.1Hz respiration was observed to be very meaningful from time domain and frequency domain analysis in relation to respiration and autonomic regulation of the heart.