• Journal of Korea Spatial Information System Society
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• 제12권1호
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• pp.49-56
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• 2010

Many researches of frequent pattern mining technique for detecting unknown patterns on spatial data have studied actively. Existing data structures have classified into tree-structure and array-structure, and those structures show the weakness of performance on dense or sparse data. Since spatial data have obtained the characteristics of dense and sparse patterns, it is important for us to mine quickly dense and sparse patterns using only single algorithm. In this paper, we propose novel data structure as compressed patricia frequent pattern tree and frequent pattern mining algorithm based on proposed data structure which can detect frequent patterns quickly in terms of both dense and sparse frequent patterns mining. In our experimental result, proposed algorithm proves about 10 times faster than existing FP-Growth algorithm on both dense and sparse data.

• Journal of Korean Association for Spatial Structures
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• 제6권1호
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• pp.117-127
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• 2006

Membrane structures, a kind of lightweight soft structural system, are used for spatial structures. The design procedure of membrane structures are needed to do shape finding, stress-deformation analysis and cutting pattern generation, because the material property has strong axial stiffness, but little bending stiffness. The problem of cooing pattern is highly varied in their size, curvature and material stiffness. So, the approximation inherent in cutting pattern generation methods is quite different. Therefore the ordinary computer software of structural analysis & design is not suitable for membrane structures. In this study, we develop the program for cooing pattern generation using geodesic line, and investigate the result of example's cooing pattern in detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제12권1호
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• pp.451-458
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• 2011

In order to provide the optimal location based services such as the optimal moving path search or the scheduling pattern prediction, the extraction of significant moving pattern which is considered the temporal and spatial properties of the location-based historical data of the moving objects is essential. In this paper, for the extraction of significant moving pattern we propose the location generalization method which translates the location attributes of moving object into the spatial scope information based on $R^*$-tree for more efficient patterning the continuous changes of the location of moving objects and for indexing to the 2-dimensional spatial scope. The proposed method generates the moving sequences which is satisfied the constraints of the time interval between the spatial scopes using the generalized spatial data, and extracts the significant moving patterns using them. And it can be an efficient method for the temporal pattern mining or the analysis of moving transition of the moving objects to provide the optimal location based services.

• Journal of Environmental Impact Assessment
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• 제33권4호
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• pp.155-163
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• 2024

The purpose is to explore the meaning of the open space land use space pattern from the perspective of urban heat reduction using the land-use scenario. The employed methods are as follows: (1) to calculate the cooling capacity Index for each of five land use scenarios, using the InVEST Urban Cooling Model, (2) to calculate open space entropy & morphological spatial pattern for each land use scenario, using the Guidos Spatial Pattern Toolbox, and (3) to perform a Spearman rank correlation analysis between the InVEST and Guidos results. It is found that the rank correlation is moderate between the cooling capacity Index and the open space area ratio (rho=0.50). However, other relations are low. It is observed that only the total amount of open space is likely to have a meaning from the perspective of urban heat reduction, and that other open space location spatial patterns may not have much meaning from the perspective of urban thermal environment management.

• Proceedings of the KSR Conference
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.418-429
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• 2007

This study aims to investigate the relationship between spatial layout and space use pattern in subway station. Details investigation is carried out using space syntax method and observation of people's movement in Kangnam subway station. Space syntax method describes spatial layout quantitatively. The study reveals that space use pattern can be predicted by spatial layout of subway station using space syntax method. This study suggests that by applying space syntax method in planning stage we can design subway station objectively considering passenger's movement.

• Korean Journal of Optics and Photonics
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• 제2권2호
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• pp.83-88
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• 1991

Studies on space-invariant pattern recognition have been carried out from various approaches. Pattern recognition system using SDF filter, from weighted linear summation of tranining images, has been the focus of research since its first appearence. In this thesis, off-axis pSDF spatial matched filter has been constructed by combining angular multiplexing of off-axis reference plane wave with pSDF filter made from pseudo-inverse algorithm, and transformed to phase only filter. From observation of the correlation responses in the correlation plane, it is shown that proposed off-axis pSDF spatial matched filter is available to pattern classification and can be used for optical correlator.

• Analyses & Alternatives
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• 제2권2호
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• pp.93-110
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• 2018

Due to its speciality, Johannesburg has drawn wide attention from the international academia, which the existing urban theory cannot easily explain. This paper focuses on the spatial pattern of Johannesburg, and finds that it is highly fragmented: first North-South Division due to apartheid and gold mining, secondly, the continuous sprawl due to population densification, and thirdly formation of city-region due to the fill-in spatial policy. The fragmented spatial pattern undermines the social integration and weakens the potential economic sustainability, which make the balanced multi-core spatial pattern inevitable under the influence of the international planning thought. The Johannesburg's spatial transformation comes not only from social integration, but also from the development vison of world-class status of an African city. In reality, since the collapse of apartheid, the municipal government has released series of strategic planning in different executive phase. These different plannings unanimously focus on the world class status although since 2008, the social inclusiveness is more emphasized. Thus, Johannesburg implements some spatial policies, as promoting the corridor of freedom, identifying the key nodes in the city then developing with high density, implementing the in-filling policy, managing the urban growth boundary, effectively preserving the natural system. However, the industrial structure in Johannesburg is already quite high-ended which cannot produce many jobs and also require much investment in advanced infrastructure. Thus, the strategic goals of world-class status of an African city and social inclusiveness which really need widely shared public services to some extent are in tension. After evaluation, we can see that spatial transformation is quite limited. Obviously spatial transformation largely depends on the social-economy. The population is still in flow. In this sense Johannesburg must energetically support the employment-based industry, effectively control the spatial sprawl and carry out institutional innovation which further incentive investment, gradually build an integrated regional governance. In general, how Johannesburg combines globalization and its own condition is still worth thinking in both theory and practice.

• Bulletin of the Korean Mathematical Society
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• 제52권4호
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• pp.1113-1122
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• 2015

This paper is concerned with the pattern formation of a diffusive predator-prey model with two time delays. Based upon an analysis of Hopf bifurcation, we demonstrate that time delays can induce spatial patterns under some conditions. Moreover, by use of a series of numerical simulations, we show that the type of spatial patterns is the spiral wave. Finally, we demonstrate that the spiral wave is asymptotically stable.

• Korean journal of applied entomology
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• 제32권2호
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• pp.134-138
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• 1993

Larval densities and spatial distribution patterns of beet armyWorm, Spodoptera exigua, were studied in the welsh onion field located in Asan from June to November, 1991. During the period, there were two denslty-peaks;mid August and mid~late September. The larvae showed clumped distribution patterns. but the patterns changed into random as larval density decreased in Oct.ober. Each larval instar showed clumped pattern expect 6th instar surveyed on September 25, which distributed in a random pattern. The larval distribution pattern were also influenced by the host plants;clumped pattern on such host. as red pepper and welsh onion, versus random pattern on such hosts as chrysanthemum, peanut and soybean.

• Journal of Biomedical Engineering Research
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• 제27권1호
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• pp.22-29
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• 2006

This paper proposes an efficient array beamforming method using spatial matched filtering for ultrasound imaging. In the proposed method, ultrasound waves are transmitted from an array subaperture with fixed transmit focus as in conventional array imaging. At receive, radio frequency (RF) echo signals from each receive channel are passed through a spatial matched filter that is constructed based on the system transmit-receive spatial impulse response. The filtered echo signals are then summed. The filter remaps and spatially registers the acoustic energy from each element so that the pulse-echo impulse response of the summed output is focused with acceptably low side lobes. Analytical beam pattern analysis and simulation results using a linear array show that the proposed spatial filtering method can provide more improved spatial resolution and contrast-to-noise ratio (CNR) compared with conventional dynamic receive focusing (DRF) method by implementing two-way dynamically focused beam pattern throughout the field.