• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.566-567
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.85-85
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• 2003

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.25-28
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• 2002

This paper presents variable bit rate(VBR) rate control scheme based on MPEG-4 VM8 rate control scheme. An initial Q searching method provides more accurate bit allocation for the first frame. A frame skipping and RD Model update scheme when coded frame quality is too low or high prevents image quality fluctuation.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.370-381
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• 2005

Mobile IP provides an efficient and scalable mechanism for host mobility within the Internet. Using Mobile If, mobile nodes may change their point of attachment to the Internet without changing their If address. However, it would result in a high signaling cost. To reduce the signaling cost, we factor in the fact that mobile users will not be actively communicating much of the time. In fact, there Is no necessity to send a binding update message to the home agent when an mobile node does not communicates with others while moving. From this point of view, we propose a lazy update strategy for minimizing signaling cost using the forwarding pointer in hierarchical Mobile IPv6. In our proposal, binding updates are sent only when a mobile node is in a busy mode. If an mobile node is in a dormant mode, binding update messages are delayed until busy mode using the forwarding pointer. As a result, our proposal can reduce the total signaling cost by eliminating unnecessary binding update messages when a mobile node Is in a dormant mode. In addition to, our proposal reduces unnecessary location update cost resulting from ping-pong effect under mobile node's dormant mode. Analysis results using the discrete analytic model presented in this paper shows that our proposal can has superior performance than hierarchical Mobile nv6 when the call-to-mobility ratio is low and the length of the forwarding pointer chain K is low.

• Journal of KIISE:Databases
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• v.29 no.1
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• pp.1-14
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• 2002

Association rule discovery is a method of mining for the associated item set on large databases based on support and confidence threshold. The discovered association rules can be applied to the marketing pattern analysis in E-commerce, large shopping mall and so on. The association rule discovery makes multiple scan over the database storing large transaction data, thus, the algorithm requiring very high overhead might not be useful in real-time association rule discovery in dynamic environment. Therefore this paper proposes an active candidate set management model based on trigger and incremental update mechanism to overcome non-realtime limitation of association rule discovery. In order to implement the proposed model, we not only describe an implementation model for incremental updating operation, but also evaluate the performance characteristics of this model through the experiment.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.47-54
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• 2015

The popularity and adoption of smart-phones has greatly stimulated the spread of mobile malware, especially on the popular platforms such as Android. The fluidity of application markets complicate smart-phone security. There is a pressing need to develop effective solutions. Although recent efforts have shed light on particular security issues, there remains little insight into broader security characteristics of smart-phone application. Now, the analytical methods used mainly are the reverse engineering-based analysis and the sandbox-based analysis. Such methods are can be analyzed in detail. but, they take a lot of time and have a one-time payout. In this study, we develop a system to monitor that mobile application permissions at application update. We had to overcome a one-time analysis. This study is a service-based malware analysis, It will be based will be based on the mobile security study.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.52-62
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• 1997

To reconstruct the complete 3-D shape of an object, seveal range images form different viewpoints should be merged into a single model. The process of extraction of the transformation parameters between multiple range views is calle dregistration. In this paper, we propose a new algorithm to find the transformation parameters between multiple range views. Th eproposed algorithm consists of two step: initial estimation and iteratively update the transformation. To guess the initial transformation, we modify the principal axes by considering the projection effect, due to the difference fo viewpoints. Then, the following process is iterated: in order to extract the exact transformation parameters between the range views: For every point of the common region, find the nearest point among the neighborhood of the current corresponding point whose correspondency is defined by the reverse calibration of the range finder. Then, update the transformation to satisfy the new correspondencies. In order to evaluate the performance the proposed registration algorithm, some experiments are performed on real range data, acquired by space encoding range finder. The experimental results show that the proposed initial estimation accelerate the following iterative registration step.

• The Journal of Information Systems
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• v.10 no.1
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• pp.279-301
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• 2001

This study was examined empirically the relationship between exogenous and endogenous variables to use internet shopping malls. Exogenous variables in our model are retrieval simpleness, quality of order treatment, web reputation, update and system quality and endogenous variables are perceived usefulness, perceived ease of use and intention of using internet shopping malls. The results of the path analysis are shown as follows. All exogenous variables have a direct effect on perceived ease of use while both retrieval simpleness and update has a direct effect on perceived usefulness. The perceived ease of use has a direct effect on the intention of using internet shopping malls and has a indirect effect on the intention through perceived usefulness. Especially, web reputation among the exogenous variables has the strongest impact on the perceived ease of use and retrieval has the strongest impact on the perceived usefulness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.9
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• pp.1668-1683
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• 2011

The importance of secure communication between only legitimate group members in ad hoc networks has been growing in recent years. Due to the ad hoc nature the scalability on dynamic membership change is a major concern. However, the previous models require at least O(log n) communication cost for key update per each membership change, which imposes a heavy burden on the devices. In this paper we present a scalable model that supports communication-efficient membership change in ad hoc networks by exclusionary keys and RSA functions. The multicast cost for key update is extremely low, that is O(1) , and one-to-one communications occur mostly in neighboring devices.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.27-50
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• 2009

This paper describes an adaptive management approach for predicting, monitoring, and controlling ground movements associated with excavations in urban areas. Successful use of monitoring data to update performance predictions of supported excavations depends equally on reasonable numerical simulations of performance, the type of monitoring data used as observations, and the optimization techniques used to minimize the difference between predictions and observed performance. This paper summarizes each of these factors and emphasizes their inter-dependence. Numerical considerations are described, including the initial stress and boundary conditions, the importance of reasonable representation of the construction process, and factors affecting the selection of the constitutive model. Monitoring data that can be used in conjunction with current numerical capabilities are discussed, including laser scanning and webcams for developing an accurate record of construction activities, and automated and remote instrumentations to measure movements. Self-updating numerical models that have been successfully used to compute anticipated ground movements, update predictions of field observations and to learn from field observations are summarized. Applications of these techniques from case studies are presented to illustrate the capabilities of this approach.