• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.1-8
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• 2010

Noise removal methods for noisy images have been studied a lot in the domain of spatial and transform filtering. Low pass filtering was initially applied in the spatial domain. Recently, discrete wavelet transform has widely used for image denoising as well as image compression due to an excellent energy compaction and a property of multiresolution. In this paper, Gabor cosine and sine transform which is considered as human visual filter is applied to image denoising areas using soft thresholding technique. GCST is compared with excellent wavelet transform which uses existing soft thresholding methods from PSNR point of view. Resultant images removed noises are also visually compared. Experimental results with adding four different standard deviation levels of Gaussian distributed noises to real images show that the proposed transform has better PSNR performance of a maximum of 1.18 dB and visible perception than wavelet transform.

• Korea-Australia Rheology Journal
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• v.17 no.3
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• pp.99-110
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• 2005

This work presents results of finite element analysis of isothermal incompressible creeping viscoelastic flows with the tensor-logarithmic formulation of the Leonov model especially for the planar geometry with singular comers in the domain. In the case of 4:1 contraction flow, for all 5 meshes we have obtained solutions over the Deborah number of 100, even though there exists slight decrease of convergence limit as the mesh becomes finer. From this analysis, singular behavior of the comer vortex has been clearly seen and proper interpolation of variables in terms of the logarithmic transformation is demonstrated. Solutions of 4:1:4 contraction/expansion flow are also presented, where there exists 2 singular comers. 5 different types spatial resolutions are also employed, in which convergent solutions are obtained over the Deborah number of 10. Although the convergence limit is rather low in comparison with the result of the contraction flow, the results presented herein seem to be the only numerical outcome available for this flow type. As the flow rate increases, the upstream vortex increases, but the downstream vortex decreases in their size. In addition, peculiar deflection of the streamlines near the exit comer has been found. When the spatial resolution is fine enough and the Deborah number is high, small lip vortex just before the exit comer has been observed. It seems to occur due to abrupt expansion of the elastic liquid through the constriction exit that accompanies sudden relaxation of elastic deformation.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.209-214
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• 2004

Time Domain Reflectometry with multiplex system has been installed to configure the spatial and temporal characteristics of soil moisture in a mountainous hillslope. An intensive surveying was performed to build a refined digital elevation model and flow determination algorithms with inverse surveying have been applied to establish an efficient soil monitoring system. Steady state wetness index, quasi-dynamic wetness index and fully dynamic wetness index have been calculated. Continuous monitoring of soil moisture data were analyized with wetness indices. Limitations and hydrological interpretations of this approach have beer discussed.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.213-216
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• 2001

The H.263 Annex I method for the intraframe coding is based on the prediction in DCT domain, unlike JPEG, MPEG-1, and MPEG-2 where the intraframe coding uses block DCT, independent of the neighboring blocks. In this paper, we show the ineffectiveness of H.263 Annex I prediction method by mathematically deriving the spatial domain meaning of H.263 Annex I prediction method. Based on the derivation, we propose a prediction method which is based on the spatial correlation property of image signals. From the experiment and derivation, we verified the proposed method.

• Journal of Cadastre & Land InformatiX
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• v.45 no.1
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• pp.193-205
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• 2015

The existing 2D cadastre as the core engine of land administration systems met with the difficulty of managing and representing the real 3D world. As a result, a 3D cadastre system has emerged as a solution oriented towards managing, representing and providing 3D spatial information related to physical status, land rights, restrictions and responsibilities. The aim of this study is to establish the foundation of the 3D cadastre information system. With this in mind, this paper aims not only to set up the data range of the 3D cadastre, but also to design a conceptual model based on an LADM (Land Administration Domain Model) through the investigation of legal restrictions and land uses relating to spaces in 3D.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.2
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• pp.113-119
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• 2006

Image steganography is a secret communication method used to transmit secret messages that have been embedded into an image. To accommodate a secret message in a digital image, the original cover image is modified by the embedding algorithm. As a result, a stego image is obtained. The sender hides the secret message in a cover image that has no meaning, and then transmits the stego image to the receiver. In this paper, we propose a steganographic method based on spatial domain to embed a secret message using a difference value of two consecutive pixels and a secret quantization range. Especially, we use the modular operation for increasing of insertion information. Through experiments, we have shown that the proposed method has much mon payload capacity, average 60 percent, than some existing methods by using modular operation.

• International Journal of Computer Science & Network Security
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• v.22 no.7
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• pp.147-156
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• 2022

Ontologies are knowledge containers in which information about a specified domain can be shared and reused. An event happens within a specific time and place and in which some actors engage and show specific action features. The fact is that several ontology models are based on events called Event-Based Models, where the event is an individual entity or concept connected with other entities to describe the underlying ontology because the event can be composed of spatiotemporal extents. However, current event-based ontologies are inadequate to bridge the gap between spatiotemporal extents and participants to describe a specific domain event. This paper reviews, describes and compares the existing event-based ontologies. The paper compares various ways of representing the events and how they have been modelled, constructed, and integrated with the ontologies. The primary criterion for comparison is based on the events' ability to represent spatial and temporal extent and the participants in the event.

• Education of Primary School Mathematics
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• v.17 no.2
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• pp.159-171
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• 2014

Spatial ability has been valued as one component of intelligence and as an talented domain. And it is associated with the achievements in science, technology, engineering, and mathematics (STEM) disciplines. So, the instrument for measuring spatial ability is very important. The purpose of this study is to develop Spatial Visualization Tests for Elementary School Children and examine internal consistency reliability evidence and construct validity evidence on confirmatory factor analysis of that instrument. For this purpose, 'The Spatial Visualization Tests for Elementary School Children was administered to 1482 Korean elementary school students. As a result, this study show that internal consistency reliability evidence using Cronbach' alpha showed item consistency and construct validity evidence from confirmatory factor analysis in the Spatial Visualization Tests for Elementary School Children. And also, this study show ed that item difficulty and item discrimination of the Spatial Visualization Tests for Elementary School Children were within an acceptable range.

• Spatial Information Research
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• v.21 no.2
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• pp.11-21
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• 2013

W ith the recent increasing build and application for 3D spatial information, the importance of management and application for spatial information based on indoor space has been increased. Especially, Due to the increasing of the scale and complexity of the building according to the development of construction technologies several studies have been conducted to provide the services based on indoor space such as indoor navigation for disaster. Therefore, to efficient manage and service for information of complicated indoor space, it is necessary to extend and develop 3D spatial model and services that have been developed for outdoor space. In this paper, Indoor Spatial Data Model(ISDM) is developed to support building spatial information for complicated indoor space and location based services through topological information. ISDM contains a feature model which is a CityGML Application Domain Extension(ADE) model and a topology model that refers the IndoorGML.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.121-133
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• 2017

Technical regulations in the spatial information domain have been developed by a variety of independent organizations and raised inconsistent and overlapping problems with spatial information standards. Many research projects have been done to solve these problems but due to the difficulty of changing or modifying existing administrative regulations, almost nothing has happened for the harmonization. As a response to the fundamental problem, KATS (Korean Agency for Technology and Standards) recently switched the existing system to "trans- governmental participatory standard operation system" and the administrative change created an independent and consistent standard system in the Ministry of Land, Infrastructure and Transport. The Ministry, as a part of the effort, established its own KSDI(Korean Spatial Data Infrastructure) Standard system. From this context this paper presents a redefinition of technical regulation for the harmonization with spatial information standards, an association model between the standards and regulations, and a maintenance methodology to solve the fore-mentioned problems.