• Journal of Korean Society of Transportation
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• v.14 no.1
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• pp.51-67
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• 1996

The optimal path-finding problem becomes complicated when multiple variables are simultaneously considered such as physical route length, degree of congestion, traffic capacity of intersections, number of intersections and lanes, and existence of free ways. Therefore, many researchers in various fields (management science, computer science, applied mathematics, production planning, satellite launching) attempted to solve the problem by ignoring many variables for problem simplification, by developing intelligent algorithms, or by developing high-speed hardware. In this research, an integration of expert system technique and case-based reasoning in high level with a conventional algorithms in lower level was attempted to develop an optimal path-finding system. Early application of experienced driver's knowledge and case data accumulated in case base drastically reduces number of possible combinations of optimal paths by generating promising alternatives and by eliminating non-profitable alternatives. Then, employment of a conventional optimization algorithm provides faster search mechanisms than other methods such as bidirectional algorithm and $A^*$ algorithm. The conclusion obtained from repeated laboratory experiments with real traffic data in Seoul metropolitan area shows that the integrated approach to finding optimal paths with consideration of various real world constraints provides reasonable solution in a faster way than others.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.06a
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• pp.29-29
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• 2004

Long term observational analysis by climatologists has confirmedthat the global warming is no longer a topic of debate among scientists andpolicy makers. According to the report of IPCC-2001 (Intergovernmental Panelon Climate Change), the global mean surface air temperature is increasinggradually. The reported increase of mean temperature is by 0.6 degree in the end of twentieth century. This could represent severe threat for propertylosses especially due to increase in the number of extreme weather arising out of global warming. period of model integration from 2001 to 2100 using output of ECHAM4/HOPE-G of Max Planet Institute of Meteorology (MPI) for IPCC SRES (Special Report on Emission Scenarios). The main results of this study indicate increase of surface air temperature by 6.20C and precipitation by 2.6% over Korea in the end of 21st century. Simulation results also show that there is increase in daily maximum and minimum temperatures while decrease in diurnal temperature range (DTR). DTR changes are diminished mainly due to relatively rapid increase of daily minimum temperature than that of daily maximumtemperature. It has been observed that increase in precipitation amount anddecrease in the number of rainy days lead to increase of pre precipitationintensity.

• Korean Journal of Child Studies
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• v.32 no.4
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• pp.147-166
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• 2011

The purpose of this study was to explore the relationship between cultural identity and the psychosocial adjustment levels of children in international marriage families by focusing on the effects that different types of cultural identity have on children's overall psychosocial adjustment. The data for this study came from a survey conducted on 122 third to sixth grades children with foreign mothers living in Seoul and Gyeonggi-Do. As a result, it was found that children's identification with Korean culture was on average higher than their identification with their mother's culture. Secondly, in terms of identity type, assimilation and separation types appeared to be the most dominant, followed by the integration and marginalization types. Finally, it was found that cultural identities had significant effects on children's psychosocial adjustment in international marriage families. In particular, the level of self-esteem was the highest for children in the integrated group, while it was the lowest for those in the marginalized group. These results indicate that identification with the mother's culture is just as important as one's Korean identity when it comes to determining the degree of psychosocial adjustment of children in international marriage families.

• Journal of Korean Academy of Nursing
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• v.17 no.1
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• pp.79-87
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• 1987

Study was to identify the structural and functional characteristics of social support system to better provide social support to physically handicapped children. The research design was a comparative descriptive study and the data were obtained by use of interview and questionnaire. The result of this were as follows: 1. The physically handicapped children perceived that they had a fewer number of social support providers than the non-handicapped children. (t= -4.62, p<.001) 2. The physically handicapped children Perceived a lower level of social support than the non-handicapped children. (t= -3.93, p<.001) In the cases of 3 types of social support (social integration, attachment / intimacy, assistance/guidance), the handicapped children perceived a lower level of social support. 3. It was found that physically handicapped children and nonhandicapped children perceived degree of social support differently (x$^2$=72.08, p<.001). and also the two groups perceived in all types of social support differently. 4. The results of this study showed that parents, school mates, school teachers, brothers and sisters were significant providers of social support and between the two groups the supportive source ranked consistently. (rs=.83, p<.01) 5. The relationship between sociability and the support level was a positive correlation (r=.28, p<.01), the relationship between sociability and the size of the support network showed a positive correlation. (r=.47, p<.01) And with the increase in the number of friends. the number of support providers increased. (F= 4.46, p<.05).

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.103-110
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• 2013

This study aims to draw the basis documents for rural landscape management of Daewon-Ri through frequency analysis of landscape elements and preference analysis of rural landscape. The results are as follows. First, according to the frequency analysis of the landscape elements, a distant view is few effect characteristics in rural village landscape planning. It is acted as the landscape elements that degree of integration and skyline of the building to see more nearby than it are the most important. In addition, in the case of the establishment of the landscape management planning, the landscape elements in the close view is the most important. Second, It is thought that the scenery which natural environments and residential quarter match is the most desirable for the par of the landscape preference in the rural village. On the other hand, about the scenery of an old historic building, the residents of a city considers it as an affirmative factor of the rural village landscape, but rural village inhabitants are negative. Finally, it is thought that the excessive public designs by government sponsored enterprise are undesirable for the scene of the village.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.2
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• pp.85-105
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• 1994

As an exploratory attempt, this study examined the correlates of different strategic groups in the Korean health food industry. Many prior studies believe that different entry mode such as entry timing and patterns, and different cognitive structure of top managers lead to the formation of different strategic groups in the same industry. Different strategic groups with different sources or mobility barriers are also expected to produce different level of economic performance. Multivariate statistical analyses of data from 32 firms in the Korean health food industry revealed the following results. i) There are four different strategic groups with different levels of mobility barriers in terms of firm size, scope of product/market domain, degree of forward and backward integration. ii) Differences in both entry timing and environmental perception of top managers are associated with different stratetic groups. However, the patterns of entry are not significantly different among four strategic groups. iii) Four strategic groups exhibit different level of economic performance in terms of sales growth rate and return on investment. Finally, this study tried to identify commonalities and differences among various strategic groups found in several industries in Korea. The results offered some implications to search for developing a useful theory of strategic groups in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.35-39
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• 1994

One of the important characteristics of the response of nonlinear systems is the existence of subharmonic resonances. When some conditions in parameter space are satisfied. It is possible even in the presence of damping for a periodically excited nonlinear system to possess a response which is the combination of a contribution at the excitation frequency and a component at the system natural frequency. The system natural frequency being a submultiple of the excitation frequency implies that the resulting response is a subharmonic oscillation. In general, there also co-exists, for the system, a response at the excitation frequency, and initial conditions determine which of the steady-state responses is achieved in an experiment or a numerical simulation. In single-degree-of-freedom systems with harmonic excitation, depending on the type of the nonlinearity, e.g., cubic or quadratic the frequency of subharmonic response is respectively, one-third or one-half of that of the excitation frequency. Although subharmonic resonance is one of the principal characteristics of a nonlinear system the subharmonic responses of structures in the presence of internal resonances have been studied very rarely. In this work, we consider subharmonic responses in the two-mode approximation of the plate equations. It is assumed that the two modes are in one-to-one internal resonance. Constant and periodic steady-state solutions of the averaged equations are studied. Finally, the results of direct time integration of the original equations of motion are presented and compared with those obtained from the averaged equations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.37-45
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• 2002

A two-dimensional unsteady, inviscid flow solver has been developed for the simulation of airfoil-vortex interactions on unstructured dynamically adapted meshes. The Euler solver is based on a second-order accurate implicit time integration using a point Gauss-Seidel relaxation scheme and a dual time-step subiteration. A vertex-centered, finite-volume discretization is used in conjunction with the Roe's flux-difference splitting. An unsteady solution-adaptive dynamic mesh scheme is used by adding and deleting mesh points to take account of both spatial and temporal variations of the flow field. The effect of vortex interaction on the aeroelastic displacement of an airfoil attached to the idealized two degree-of-freedom spring system is investigated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.4
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• pp.1441-1456
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• 2015

The bidimensional empirical mode decomposition (BEMD) algorithm with high adaptability is more suitable to process multiple image fusion than traditional image fusion. However, the advantages of this algorithm are limited by the end effects problem, multiscale integration problem and number difference of intrinsic mode functions in multiple images decomposition. This study proposes the multiscale self-coordination BEMD algorithm to solve this problem. This algorithm outside extending the feather information with the support vector machine which has a high degree of generalization, then it also overcomes the BEMD end effects problem with conventional mirror extension methods of data processing,. The coordination of the extreme value point of the source image helps solve the problem of multiscale information fusion. Results show that the proposed method is better than the wavelet and NSCT method in retaining the characteristics of the source image information and the details of the mutation information inherited from the source image and in significantly improving the signal-to-noise ratio.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.43-56
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• 2011

An integrated system composed of guidance, navigation and control (GNC) system for autonomous proximity operations and the docking of two spacecraft was developed. The position maneuvers were determined through the integration of the state-dependent Riccati equation formulated from nonlinear relative motion dynamics and relative navigation using rendezvous laser vision (Lidar) and a vision sensor system. In the vision sensor system, a switch between sensors was made along the approach phase in order to provide continuously effective navigation. As an extension of the rendezvous laser vision system, an automated terminal guidance scheme based on the Clohessy-Wiltshire state transition matrix was used to formulate a "V-bar hopping approach" reference trajectory. A proximity operations strategy was then adapted from the approach strategy used with the automated transfer vehicle. The attitude maneuvers, determined from a linear quadratic Gaussian-type control including quaternion based attitude estimation using star trackers or a vision sensor system, provided precise attitude control and robustness under uncertainties in the moments of inertia and external disturbances. These functions were then integrated into an autonomous GNC system that can perform proximity operations and meet all conditions for successful docking. A six-degree of freedom simulation was used to demonstrate the effectiveness of the integrated system.