• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.165-172
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• 2011

Wireless sensor networks consist of small battery powered devices with limited energy resources. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of the network. Directed Diffusion is a well known routing protocol. In this paper we adopt the clustering mechanism to improve the efficiency of Directed Diffusion. We introduce C-Directed Diffusion which make clusters, select the CH(Cluster Head) and CHs do the same process as in Directed Diffusion. C-Directed Diffusion is pretty simple and show better performance than Directed Diffusion.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.3-6
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• 2003

A nonlinear iterative filtering based on local statistics and anisotropic diffusion is introduced. Local statistics determines the diffusion coefficient at each iteration step. Anisotropic diffusion can be seen as estimates a piecewise smooth image from the noisy input image in the experimental section, our results are shown to suppress noise with preserving the edges. Therefore, it enhances the image and improves performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.542-549
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• 2007

Recently, many research activities in the image processing area are concentrated on developing new algorithms by finding the solution of the 'diffusion equation'. The diffusion algorithms are expected to be utilized in numerous applications including noise removal and image restoration, edge detection, segmentation, etc. In this paper, at first, it will be shown that the anisotropic diffusion algorithms have the similar structure with the adaptive FIR filters with cross-shaped 5-tap kernel, and this relatively small-sized kernel causes many iterating procedure for satisfactory filtering effects. Moreover, it will also be shown that lots of modifications which are adopted to the conventional Gaussian diffusion method in order to weaken the edge blurring nature of the linear filtering process increases another computational burden. We propose a new Median diffusion scheme by replacing the adaptive linear filters in the diffusion process with the AWM (Adaptive Weighted Median) filters. A diffusion-equation-based adaptation scheme is also proposed. With the proposed scheme, the size of the diffusion kernel can be increased, and thus diffusion speed greatly increases. Simulation results shows that the proposed Median diffusion scheme outperforms in noise removal (especially impulsive noise), and edge preservation.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.4
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• pp.101-115
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• 2009

This study analyzed the diffusion process of digital convergence products focused on camera phon to compare the traditional adoption-diffusion model with use-diffusion model proposed by Shih and Venkatesh(2004). The results suggested that observability, perceived usefulness, innovativeness, relative advantage have effects on the intention of repurchase in the adoption-diffusion model. On the other hand, the intention of repurchase has been affected by technological sophistication, satisfaction, innovativeness, relative advantage in the use-diffusion model. These results imply that the traditional adoption-diffusion model could be applied to the cases of the digital convergence products. In addition, the results also show that the use-diffusion model is superior to the traditional model in analyzing the diffusion of digital convergence products.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.165-165
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• 2001

Purpose： To obtain quantitative diffusion-tensor anisotropy information of human cerebral structu using turbo STEAM diffusion-tensor imaging. Method： Quantitative diffusion anisotropy MR images were obtained in 7 healthy adults using turbo STEAM sequence and a combination of tetrahedral and orthogonal diffusi gradients. Both relative anisotropy(RA) and fractional anisotropy(FA) values were measured various brain regions. The anisotropy index was then compared with the reported valu resulting from EPI-based diffusion tensor imaging.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.138-138
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• 2001

Purpose： To obtain quantitative diffusion-tensor anisotropy information of human cerebral structu using turbo STEAM diffusion-tensor imaging. Method： Quantitative diffusion anisotropy MR images were obtained in 7 healthy adults using turbo STEAM sequence and a combination of tetrahedral and orthogonal diffusi gradients. Both relative anisotropy(RA) and fractional anisotropy(FA) values were measured various brain regions. The anisotropy index was then compared with the reported valu resulting from EPI-based diffusion tensor imaging.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.167-167
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• 2001

Purpose： To obtain normative human skeletal muscle data and evaluate quantitative diffusion-ten anisotropy information using diffusion-tensor imaging technique. Method： Quantitative extremity muscle diffusion tensor MR images were obtained in 5 healt adults by using turbo STEAM sequence and a combination of tetrahedral and orthogon diffusion gradients. Relative anisotropy(RA) and fractional anisotropy(FA) values we measured in soleus and gastrocnemius muscle in addition to mean ADC value.

• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.155-164
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• 2010

Until now, most of studies on Electronic Data Interchange(EDI) have been focused on the introduction of EDI and the performance of EDI. But recently, there have been increasing researches on diffusion of Electronic Data Interchange. The aims of this study are twofold. First, to find the impacts of various factors on EDI diffusion, second, to examine the relationship between EDI diffusion factors and EDI diffusion degree. To accomplish those aims of study, two kinds of methodologies are adopted in the studies, First, model building by wide investigation on previous papers, Second, empirical research for finding the determinants of diffusion of EDI. The results of testing the hypotheses of this research are summarized as follows. First, The important EDI diffusion variables influencing internal diffusion of EDI consist of top management support, scope for EDI, IS sophistication, compatibility, complexity, relative advantages, competition intensity and external pressure. Second, Top management support, scope for EDI, IS sophistication, compatibility, relative advantages, competition intensity and external pressure are associated with external diffusion of EDI. We are aware of the important fact that top management support, scope for EDI, IS sophistication, compatibility, relative advantage, competition intensity and external pressure were simultaneously associated with internal and external diffusion of EDI.

• Journal of KIISE:Information Networking
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• v.35 no.1
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• pp.34-45
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• 2008

In dynamic wireless sensor networks where sources and sinks are moving or are created/died, control overheads for route establishment are increased and thus become one of the major factors for energy consumption. This study introduces prefetching and pruning for Directed Diffusion to remove redundant control messages. Prefetching collects path information for each event with "AnyEvent" in advance and gives quick responses without further flooding of requests. Pruning accumulates history information from previous requests and replies, and then stops forwarding a request towards where the event does not exist. Simulation results with ns show that it is possible to build implicit and soft infrastructures within a Directed Diffusion system through these active collection and passive accumulation and they improve energy consumption more as control overhead goes higher.

• Journal of Korea Multimedia Society
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• v.22 no.6
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• pp.684-694
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• 2019

Information spread in networks is universal in many real-world phenomena such as propagation of infectious diseases, diffusion of a new technology, computer virus/spam infection in the internet, and tweeting and retweeting of popular topics. The problem of finding the information source is to pick out the true source if information spread. It is of practical importance because harmful diffusion can be mitigated or even blocked e.g., by vaccinating human or installing security updates. This problem has been much studied, where it has been shown that the detection probability cannot be beyond 31% even for regular trees if the number of infected nodes is sufficiently large. In this paper, we study the impact of an anti-information spreading on the original information source detection. We consider an active defender in the network who spreads the anti-information against to the original information simultaneously and propose an inverse Voronoi partition based inference approach, called Voronoi Inference to find the source. We perform various simulations for the proposed method and obtain the detection probability that outperforms to the existing prior work.