• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5244-5259
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• 2019

With the continuous development of LBS (Location Based Service) applications, privacy protection has become an urgent problem to be solved. Differential privacy technology is based on strict mathematical theory that provides strong privacy guarantees where it supposes that the attacker has the worst-case background knowledge and that knowledge has been applied to different research directions such as data query, release, and mining. The difficulty of this research is how to ensure data availability while protecting privacy. Spatial multidimensional data are usually released by partitioning the domain into disjointed subsets, then generating a hierarchical index. The traditional data-dependent partition methods need to allocate a part of the privacy budgets for the partitioning process and split the budget among all the steps, which is inefficient. To address such issues, a novel two-step partition algorithm is proposed. First, we partition the original dataset into fixed grids, inject noise and synthesize a dataset according to the noisy count. Second, we perform IH-Tree (Improved H-Tree) partition on the synthetic dataset and use the resulting partition keys to split the original dataset. The algorithm can save the privacy budget allocated to the partitioning process and obtain a more accurate release. The algorithm has been tested on three real-world datasets and compares the accuracy with the state-of-the-art algorithms. The experimental results show that the relative errors of the range query are considerably reduced, especially on the large scale dataset.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.125-134
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• 2001

The objective of this study is the development of size discrete optimum design algorithm which is based on the GAs(genetic algorithms). The algorithm can perform size discrete optimum designs of space trusses. The developed algorithm was implemented in a computer program. For the optimum design, the objective function is the weight of space trusses and the constraints are limite state design codes(1998) and displacements. The basic search method for the optimum design is the GAs. The algorithm is known to be very efficient for the discrete optimization. This study solves the problem by introducing the GAs. The GAs consists of genetic process and evolutionary process. The genetic process selects the next design points based on the survivability of the current design points. The evolutionary process evaluates the survivability of the design points selected from the genetic process. In the genetic process of the simple GAs, there are three basic operators: reproduction, cross-over, and mutation operators. The efficiency and validity of the developed discrete optimum design algorithm was verified by applying GAs to optimum design examples.

• Journal of Korean Association for Spatial Structures
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• v.8 no.1
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• pp.49-56
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• 2008

A multi-objective optimization approach is presented for force design of tensegrity structures. The geometry of the structure is given a priori. The design variables are the member forces, and the objective functions are the lowest eigenvalue of the tangent stiffness matrix that is to be maximized, and the deviation of the member forces from the target values that is to be minimized. The multi-objective programming problem is converted to a series of single-objective programming problems by using the constraint approach. A set of Pareto optimal solutions are generated for a tensegrity grid to demonstrate the validity of the proposed method.

• Spatial Information Research
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• v.14 no.2 s.37
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• pp.191-209
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• 2006

This study is analyzing what necessary law and institution is to solve various problem that is happened in process that execute the first$\sim$second National GIS Master Plan in the meantime at visual point that the second National GIS Master Plan(2001-2005) period is expired. Specially, it is that present what improvement direction of law and institution by each field is. Minimize of obstacle factors far National GIS Master Plan is purposeful during the third National GIS Master Plan period. To achieve study purpose, this study analyzes background of National GIS law and institution, objective, system. It is expected that of this article can contribute to the picture of National GIS law and institution.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.49-55
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• 2012

This paper proposes an efficient method of object identification and localization for image recognition. The new proposed algorithm utilizes correlogram back-projection in the YCbCr chromaticity components to handle the problem of sub-region querying. Utilizing similar spatial color information enables users to detect and locate primary location and candidate regions accurately, without the need for additional information about the number of objects. Comparing this proposed algorithm to existing methods, experimental results show that improvement of 21% was observed. These results reveal that color correlogram is markedly more effective than color histogram for this task. Main contribution of this paper is that a different way of treating color spaces and a histogram measure, which involves information on spatial color, are applied in object localization. This approach opens up new opportunities for object detection for the use in the area of interactive image and 2-D based augmented reality.

• Fire Science and Engineering
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• v.25 no.6
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• pp.156-167
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• 2011

The number of buildings is growing at a rapid pace in Korea. It is driven by significant economic improvements, the rapid population growth and urban centralization. Such being this case, some city are underway to building enlargement, Manhattanization. To Solve these problem and ensure the safety of live, fire Evacuation Simulation system is used for safe check of buildings. Forecasting an egress behavior in building fire is so important in order to construct a safe and reliable environment. But, currently most of the fire evacuation simulation system used in practice are foreign software that is not reflect korean conditions. Thus, This study focus on objectives that develop a fire evacuation system considering Korean Characteristics and create 3D space-based topology. so the system calculate evacuation path. This system developed as a result of research can be used by architectural designer in practice due to it is based 3D spatial information modeling.

• Journal of Korean Association for Spatial Structures
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• v.5 no.3 s.17
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• pp.101-107
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• 2005

An analytic study on the bond stress between steel tube and concrete in concrete filled steel(CFT) tublar column is presented in this paper. Recently buildings need members which are enhanced durability and ductility. Concrete filled tublar column system is proposed as alternative plan. In this paper, ABAQUS/Standard Version 5.8 which is identified as usefulness for finite element analysis and has various element library is used. The variables in this study are the location and type of shear-connector. The modeling ell contact problem practiced by Contact Pair and Contact Pressure method. In the step of physical bond, it is practiced by Change friction option. After yielding of models, analytic results is less than that of experimental results.

• Journal of Korean Association for Spatial Structures
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• v.16 no.2
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• pp.79-88
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• 2016

Modular buildings are constructed by assembling modular units which are prefabricated in a factory and delivered to the site. However, due to a problem of noise between floors, concrete slab is usually poured at the top or bottom level of a modular unit in Korea. This greatly increases the weight of buildings, but designing vertical members of modular units to resist overall gravity loads is very inefficient. In this study, considering domestic building construction practices, feasible structural systems for tall modular buildings are proposed in which separate steel frames and reinforced concrete core walls are designed to resist gravity and lateral loads. To verify performance, a three-dimensional structural analysis has been performed with two types of prototype buildings, i.e., a residential building and a hotel. From the results, wind-induced lateral displacements and seismic story drifts are examined and compared with their limit values. Between the two kinds of buildings, the efficiency of the proposed system is also evaluated through a comparison of the weight of structural components. Finally, the effect of a floor diaphragm on the overall behavior is analyzed and discussed.

• Journal of Korean Association for Spatial Structures
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• v.12 no.1
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• pp.43-50
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• 2012

Recently, due to the advanced computer technology, momental architectures have been designed and built using features that are very sophisticated. People's interest in free-form structural system has increased steadily not only nationwide, but also worldwide. However, there were many difficulties in the materialization of free-form structural system owing to the lack of technique and research. To solve this problem, this study performs the interface between the 3D modeling program and the optimization program. In the 3D modeling program, it is possible to automatic mesh generation and immediately to information extraction. It performs the shape optimization. Consequently, this research designs the example model and performs optimization in order to verify the developed interface module.

• Journal of the Korean Institute of Educational Facilities
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• v.14 no.3
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• pp.27-35
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• 2007

The purpose of this research is to analyzing the welfare function of the senior citizen with similar type of compounding the school facility, to analyze the problematical point of present condition. And also propose the spatial constitution which the student and the regional senior citizen are easy to utilize on the basis of the result. In a type of educational facility composition, it became clear that a ratio and the inflection order that elderly welfare facilities occupied of vacant class room were low. In other words, in composition of a school facilities, elderly welfare facilities can be said to be an important problem. As a result of having analyzed an existing compound facilities, there was limited interchange of student and a the aged. In addition, there were problems such as learning environment by an intersection of circulation. Therefore, composition of educational facility and elderly welfare facilities is not space composition that is intersection of simple specification function. In other words, a program of the common space which is necessary for the local community formation is necessary. Setting of semi-public area proposes the function of the existing facility and actual condition of spatial use in prerequisite.