• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.515-522
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• 2001

Feature-based similarity retrieval become an important research issue in image database systems. The features of image data are useful to discrimination of images. In this paper, we propose the highspeed k-Nearest Neighbor search algorithm based on Self-Organizing Maps. Self-Organizing Map(SOM) provides a mapping from high dimensional feature vectors onto a two-dimensional space. A topological feature map preserves the mutual relations (similarity) in feature spaces of input data, and clusters mutually similar feature vectors in a neighboring nodes. Each node of the topological feature map holds a node vector and similar images that is closest to each node vector. We implemented about k-NN search for similar image classification as to (1) access to topological feature map, and (2) apply to pruning strategy of high speed search. We experiment on the performance of our algorithm using color feature vectors extracted from images. Promising results have been obtained in experiments.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.29-37
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• 2017

It has gradually become important to estimate a forest stand volume utilizing LiDAR data. Recently, various statistical models including a linear regression model has been introduced to estimate a forest stand volume using LiDAR data. One of limitations of the current approaches is in that the accuracy of observed forest stand volume data, which is used as a response variable, is questionable unstable. To overcome this limitation, we consider a spatial structure for a forest stand volume. In this research, we propose a hierarchical model for applying a spatial structure to a forest stand volume. The proposed model is applied to the LiDAR data and the forest stand volume for Bonghwa, Gyeongsangbuk-do.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.33-40
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• 1989

In the design of reinforced concrete framed structures, which consist of various design variables, the objective and the constraint functions are formulated in complicated forms. Usually iterative methods have been used to optimize the design variables. In this paper, multilevel formulation is adopted, and design variables are selected in reduced numbers at each level, to reduce the iterative cycle and to accelerate the convergence rate. At level 1, elastic analysis is performed to get the upper and lower bounds of the redistributed design moments due to inelastic behavior of the frame. Then the design moments are taken as design variables and optimized at level 2, and the sizing variables are optimized at level 3. The optimization of redistributed moments is performed using the design sensitivity obtained at the level 2, and force approximation technique is used to reflect the variation of design variables in the lower level to the upper level. The design variables are selected in reduced numbers at each level, and the optimization formulation is simplified effectively. A cost function is taken as the objective function, and the constraints of the stress of the structures are derived from BSI CP 110 following limit state theory. Numerical examples are included to prove the effectiveness of the developed algorithm.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.172-179
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• 2010

The Sydney Opera House is built on a peninsula of rock that juts out into Sydney Harbor. The site was once a landing place for ships. Utzon, Architect, designed the theatres for the Opera House to fit the shape. The two theatres were placed side by side so that they both had extensive harbor views. The Sydney Opera House is designed the foyers to take full advantage of these sights. Because the building would be seen from all sides, even from above, it was to be a piece of sculpture. The outside was as important as the inside. The audience enters from behind the stage and walks around to the foyers overlooking the harbour. The wing and backstage areas are small because of the way the foyers wrap around the theatre. The stage is made up of large platform lifts which provide the vertical movement for changing scenery. The sets come up from the workshops below stage. The flytower fits under the largest roof shell and doesn't break the skyline. The important elements are the podium, the shells and the reminders. The podium, the huge monolithic concrete structure, contains hundreds of rooms and nearly all the technical equipment. The podium is clad with pink granite slabs and seen from the water. This design eliminated a maze of fire escape stairs and, at the same time, gave people a wonderful view of the harbour. The egg shell is remarkably strong and express the form as the symbol of the site.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.2
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• pp.209-218
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• 1994

This study aims to generate triangulated irregular network in a form of digital terrain model which is being increasingly used. In general, grid digital elevation model and triangulated irregular network are reasonable units for solving terrain problems. But, triangulated irregular network is an efficient alternative to grid digital elevation model because of their efficiency in storing data and their convenient data structure for accommodating irregularly spaced elevation data. Various methods represented for extracting triangulated irregular networks from grid digital elevation model, and then algorithm that get accurate results for triangulation with their data set was introduced. The new approach for triangulation in this study uses the Elevation and Changeable Distance criterion, and adding interpolation points and restricted constraint lines can generate triangulated irregular network which is more close to real surface. This made database efficient construction and could be used for many applications of geo-spatial information system.

• Journal of Korea Water Resources Association
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• v.34 no.3
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• pp.241-251
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• 2001

A flow determination algorithm is proposed for the distributed hydrologic model. The advantages of a single flow direction scheme and multiple flow direction schemes are selectively considered to address the drawbacks of existing algorithms. A spatially varied flow apportioning factor is introduced in order to accommodate the accumulated area from upslope cells. The channel initiation threshold area(CIT) concept is expanded and integrated into the spatially distributed flow apportioning algorithm in order to delineate a realistic channel network. An application of a field example suggests that the linearly distributed flow apportioning scheme provides some advantages over existing approaches, such as the relaxation of over-dissipation problems near channel cells, the connectivity feature of river cells, the continuity of saturated areas and the negligence of the optimization of few parameters in existing algorithms. The effects of grid sizes are explored spatially as well as statistically.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.19-24
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• 2016

On a huge space of information called the Internet, users can use a smart mobile web to get information on various intellectual fields and can access to various Medias such as personal blogs and social networking sites (SNS). This is why a vast amount of information on the web has been effectively managed and researched nowadays through a technology named Semantic Web. However, it still needs for an improvement for studies on searching for intellectual information, though it is enhanced to integrate variously spread information and search for intellectual information user-oriented. Thus, this study aims to research on searching information and knowledge spread around a knowledge-filled information space, which can improve credibility according to user-oriented logic.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.237-244
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• 2020

This paper describes an implement of Simultaneous Localization and Mapping(SLAM) in two dimensional space. The method uses Invariant Extended Kalman Filter(IEKF), which transforms the state variables and measurement variables so that the transformed variables constitute a linear space when variables called the invariant quantities are kept constant. Therefore, the IEKF guarantees convergence provided in the invariant quantities are kept constant. The proposed IEKF approach uses Lie group matrix for the transformation. The method is tested through simulation, and the results show that the Kalman gain is constant as it is the case for the linear Kalman filter. The coherence between the estimated locations of the vehicle and the detected objects verifies the estimation performance of the method.

• Journal of Korean Association for Spatial Structures
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• v.11 no.4
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• pp.49-59
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• 2011

This paper presents a new numerical method by using Singular Value Decomposition force method for form-finding of tensegrity structures with constraints. In order to maintain the tensegrity structures stable, state of self-equilibrium stress should be introduced. The existing force method has some advantages about form-finding of tensegrity structures. However, this method has complex formulation. In force density method, dummy members are required for form -finding of tensegrity structures with constraints. Therefore this study proposes new force method using Singular value decomposition. The proposed method is both having easy basic consept and simple computation than existing force method. A numerical example is presented to demonstrate the efficiency and robustness in searching initial single integral feasible self-stress mode for tensegrity structures with constraints.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.235-241
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• 2007

AThis research is rather on the crime occurrence of target area's space scope than on the approach to the cause of specific area's crime occurrence from the perspective of the environmental criminology emphasizing the crime prevention. By observing the composition of crime distribution, it is intended to search the strategies of crime prevention actually corresponded to the crime problems. For this, after segmenting the city into six sectors, targeting city crimes in Gwangju metropolitan city, in 2004, the basic materials about the crime frequency are analyzed through dividing the types on the base of the present state of crime occurrence, the types of crime, the locations of crime occurrence, the purposes of buildings, the types of intruders, the forms of intrusions. As a result of research. it is suggested that the activation method of community police activities is necessary for the prevention of community crime prevention.