• Proceedings of the KSR Conference
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• 2004.10a
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• pp.369-374
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• 2004

Nowadays, the more speedy and functional railway vehicles are required by customers, the more broad boundary conitions of train's running are present. At this condtion, it is difficult for the traditional concept of suspension system which has the constant characteristics dependant on the running condition to meet the advenced requirements such as high ride quality. So, the active suspension should be designed to supplied the optimized suspensnion condition actively and to perform the optimal ride quality on the irregula running condition such as on the enterance or exitance of the tunnel or on the crossing the high speed train each others. On this study, the train dynamic model, integration of active suspension system, and the control logic would be proposed, and the advanced performace of train would be shown though the simulation tests.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.425-434
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• 2002

Mobility of service users makes location update and paging (L/P) procedures indispensable features in mobile communication networks. Importance of optimizing the configuration of L/P areas has been increased by the growth of L/P related signaling. In this study, we deal with the L/P configuration which an LA (Location Area) may contain multiple PAs (Paging Areas). Given the network topology, L/P related parameters, and traffics generated by each cell, is provided the problem of finding optimal LA/PA configuration minimizing the amount of L/P related signaling. The optimization problem is solved using a simulated annealing, and detailed computational results are conducted to capture the effects of mobility, call arrival patterns and boundary crossing rate on the LA and PA configurations.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.27-30
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• 2002

An experimental study is performed to investigate the characteristics of near wake behind a circular cylinder with serrated fins using the constant temperature anemometer and through flow visualization. Previous report(Boo at al., 2001) shows that there are three different modes in vortex shedding behavior. This paper is focused on the identification of the physical reasons why the difference is occured in vortex shedding. The through flow velocity crossing fins decreases as increasing fin height and decreasing fin pitch mainly due to the flow resistence. Vortex shedding is affected strongly by velocity distribution around fin tube, especially by the velocity gradient. The velocity distribution at X/d=0.0 has lower gradient with increasing freestream velocity and fin height and decreasing fin pitch. Those differences in velocity gradients generate different vortex shedding mechanism.

• Korean Journal of Mathematics
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• v.26 no.4
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• pp.683-700
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• 2018

We get one theorem which shows existence of solutions for one-dimensional jumping problem involving p-Laplacian and Dirichlet boundary condition. This theorem is that there exists at least one solution when nonlinearities crossing finite number of eigenvalues, exactly one solutions and no solution depending on the source term. We obtain these results by the eigenvalues and the corresponding normalized eigenfunctions of the p-Laplacian eigenvalue problem when 1 < p < ${\infty}$, variational reduction method and Leray-Schauder degree theory when $2{\leq}$ p < ${\infty}$.

• Journal of Internet Computing and Services
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• v.2 no.1
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• pp.31-38
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• 2001

Speech database built of phonemes is significant in the studies of speech recognition, speech synthesis and analysis, Phoneme, consist of voiced sounds and unvoiced ones, Though there are many feature differences in voiced and unvoiced sounds, the traditional algorithms for detecting the boundary between phonemes do not reflect on them and determine the boundary between phonemes by comparing parameters of current frame with those of previous frame in time domain, In this paper, we propose the assort algorithm, which is based on a block and reflecting upon the feature differences between voiced and unvoiced sounds for phoneme segmentation, The assort algorithm uses the distance measure based upon MFCC(Mel-Frequency Cepstrum Coefficient) as a comparing spectrum measure, and uses the energy, zero crossing rate, spectral energy ratio, the formant frequency to separate voiced sounds from unvoiced sounds, N, the result of out experiment, the proposed system showed about 79 percents precision subject to the 3 or 4 syllables isolated words, and improved about 8 percents in the precision over the existing phonemes segmentation system.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.3
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• pp.42-56
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• 1996

The citizens seek to maximize convenience, pleasantness and safety when they use urban facilities. However, existing practices of urban neighborhood parks have applied not qualitative standards such as adequacy, efficiency, accessibility, equity, or socioeconomic issues but very limited quantitative standards such as area per person. Therefore it is not rare that citizens have lost their accessibility to near-by neighborhood parks. And park regulations based on the distance of lien are supposed to be uniformally accomplished regardless of the consideration about users or geographical special situations. Futhermore, it has been found that some urban neighborhood parks don't reach to the standards given by the regulations. This study tries to accomplished several purposes. The first purpose is to extract the boundary of real user-accessible zones derived from the city survey. Comparing with boundary of real user-accessible zones, the second one is to propose the most efficient measurement indices among many accessibility measurement index. Based upon the above arguments, the last one is to review the propriety of the access distances(e.g., semidiameter) of an urban neighborhood park in a law. The measurement indices of accessibility examined in this study are walking distance, walking time and walking difficulty. The comparison of visual discrimination, the comparison of area and the comparison of differences of maximum distance showed similar results. Each index can also be compared in the size of area and differences of maximum distance. Walking difficulty with the turning showed the best measurement values among the measurement indices. This indicates that walking difficulty with crossing and/or turning may be another important indices in measuring accessibility, while other existing studues have mainly dealt with walking time and distance as accessibility indices. The results of this study also supported that the existing regulations related to park allocation(e.g., access diameter) are close to the findings of this study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.18-23
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• 2006

Flutter analysis of NACA 0012 with Gurney flap was conducted in time domain. Flutter analysis was performed with a conjunction of two governing equations; one is 2D Navier-Stokes equation and, the other is Lagrange equation of two dimensional plunge & pitch model. Both governing equations were coupled by loose-coupling method. From the computed results, the effect of Gurney flap was concluded to move the flutter boundary of NACA 0012 downward, which means flutter occurs at lower speed than that of NACA 0012. Although flutter boundary of gurney flap was above the safety margin when mach number was lower than 0.85, there might be a possibility of crossing the safety margin when mach number was between 0.85 and 0.9. For safety, the effect of gurney flap needs to be investigated carefully before using it.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.157-163
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• 2013

In this paper, we propose a vision and depth information based real-time hand gesture interface method using finger joint estimation. For this, the areas of left and right hands are segmented after mapping of the visual image and depth information image, and labeling and boundary noise removal is performed. Then, the centroid point and rotation angle of each hand area are calculated. Afterwards, a circle is expanded at following pattern from a centroid point of the hand to detect joint points and end points of the finger by obtaining the midway points of the hand boundary crossing and the hand model is recognized. Experimental results that our method enabled fingertip distinction and recognized various hand gestures fast and accurately. As a result of the experiment on various hand poses with the hidden fingers using both hands, the accuracy showed over 90% and the performance indicated over 25 fps. The proposed method can be used as a without contacts input interface in HCI control, education, and game applications.

• Korean Journal of Social Welfare
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• v.61 no.1
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• pp.109-134
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• 2009

Due to the change of socio-cultural conditions, family dissolving is increasing. As an alternative, grandparents who parent their grandchildren are also increasing rapidly and many show deep concern at this phenomenon. The grandparents-grandchildren families were approached through policy-makers' and professionals' perspective, not through insiders' view. The purpose of this ethnographic study were to explore the experiences and meaning-makings of grandmothers who are raising grandchildren. 22 narrative interviews with 10 grandmothers were conducted. The results of data analysis are as follows. The cultural theme in rasing experiences of grandmothers is 'Constituting a family beyond the multiple boundaries'. This theme include four cultural meanings: 'Recunstuction of everyday life beyound boundaries', 'Boundary of relative poverty more rigid than boundary of absolute poverty', 'Compromising constantly with normal culture having both inclusion and exclusion' boundaries', 'Having aspiration toward crossing the boundaries'. The policiy-makers and practitioners for the grandparents-grandchildren families should recognize the experiences and meaning-making of these families and should perform culturally perceptible and family-centered policies and practices.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.3
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• pp.111-115
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• 1997

Discrete fracture model has become one of the alternatives for the classical continuum model to simulate the irregular aspects of the fluid flow and the solute transport in fractured rocks. It is based on the assumptions that the discharge in a single fracture is proportional to the cube of the aperture and the fractured rock can be represented by the statistical assemblage of such single fractures. This study is intended to evaluate the effect of the fracture junction on the cubic law. Numerical solution of flow in junction system was obtained by using the Boundary-Fitted Coordinate System (BFCS) method. Results with different intersection angles in crossing fractures show that the geometry of the junction affects the discharge pattern under the same simulation conditions. Therefore, strict numerical and experimental examinations on this subject are required.