Vol. 5, No. 1, Feb. 2009
Yang Fei, Jong Won Park
Vol. 5, No. 1, pp. 1-4, Feb. 2009
Keywords: Level Set Methods, Evolving Algorithm, without Re-initialization, Image Segmentation
Show / Hide AbstractLevel set methods are the numerical techniques for tracking interfaces and shapes. They have been successfully used in image segmentation. A new variational level set evolving algorithm without re-initialization is presented in this paper. It consists of an internal energy term that penalizes deviations of the level set function from a signed distance function, and an external energy term that drives the motion of the zero level set toward the desired image feature. This algorithm can be easily implemented using a simple finite difference scheme. Meanwhile, not only can the initial contour can be shown anywhere in the image, but the interior contours can also be automatically detected.
Nguyen Cao Truong Hai, Kyung-Im Kim, Hyuk-Ro Park
Vol. 5, No. 1, pp. 5-10, Feb. 2009
Keywords: Latent Dirichlet Allocation, Singular Value Decomposition, Input Filtering, Text Classification, Data Preprocessing.
Show / Hide AbstractText data has always accounted for a major portion of the world¡¯s information. As the volume of information increases exponentially, the portion of text data also increases significantly. Text classification is therefore still an important area of research. LDA is an updated, probabilistic model which has been used in many applications in many other fields. As regards text data, LDA also has many applications, which has been applied various enhancements. However, it seems that no applications take care of the input for LDA. In this paper, we suggest a way to map the input space to a reduced space, which may avoid the unreliability, ambiguity and redundancy of individual terms as descriptors. The purpose of this paper is to show that LDA can be perfectly performed in a ¡°clean and clear¡± space. Experiments are conducted on 20 News Groups data sets. The results show that the proposed method can boost the classification results when the appropriate choice of rank of the reduced space is determined.
Dongwon Jeong, Heeyoung Shin, Doo-Kwon Baik, Young-Sik Jeong
Vol. 5, No. 1, pp. 11-18, Feb. 2009
Keywords: Ontology, Jena, OWL, Ontology, Storage, Hierarchical Structure
Show / Hide AbstractAs well as providing various APIs for the development of inference engines and storage models, Jena is widely used in the development of systems or tools related with Web ontology management. However, Jena still has several problems with regard to the development of real applications, one of the most important being that its query processing performance is unacceptable. This paper proposes a storage model to improve the query processing performance of the original Jena storage. The proposed storage model semantically classifies OWL elements, and stores an ontology in separately classified tables according to the classification. In particular, the hierarchical knowledge is managed, which can make the processing performance of inferable queries enhanced and stores information. It enhances the query processing performance by using hierarchical knowledge. For this paper an experimental evaluation was conducted, the results of which showed that the proposed storage model provides a improved performance compared with Jena.
You-Jin Song, Jae-Geol Yim
Vol. 5, No. 1, pp. 19-24, Feb. 2009
Keywords: Privacy, Web service, Petri Net, Context Framework
Show / Hide AbstractMany researchers have developed frameworks that are capable of handling context information and can be adapted and used by any Web service. However, no research involving the systematic analysis of existing frameworks has yet been conducted. This paper examines the Context Framework, an example of existing frameworks, using a Petri net, and analyzes its advantages and disadvantages. Then, a Petri net model – with its disadvantages removed - is introduced, and a new framework is presented on the basis of that model. The proposed PAWS (Privacy Aware Web Services) framework has a expandability for context management and communicates flexible context information for every session. The proposed framework can solve overhead problems of context in SOAP messages. It also protects user privacy according to user preferences.
Vol. 5, No. 1, pp. 25-32, Feb. 2009
Keywords: IPTV, Premium Backbone, QoS, multicast, High Availability, Security
Show / Hide AbstractIt is absolutely essential to implement advanced IP network technologies such as QoS, Multicast, High Availability, and Security in order to provide real-time services like IPTV via IP backbone network. In reality, the existing commercial networks of internet service providers are subject to certain technical difficulties and limitations in embodying those technologies. On-going research efforts involve the experimental engineering works and implementation experience to trigger IPTV service on the premium-level IP backbone which has recently been developed. This paper introduces the core network technologies that will enable the deployment of a high-quality IPTV service, and then proposes a suitable methodology for application and deployment policies on each technology to lead the establishment and globalization of the IPTV service.
Byung-Gyu No, Doo-Soon Park, Min Hong, HwaMin Lee, Yoon Sok Park
Vol. 5, No. 1, pp. 33-40, Feb. 2009
Keywords: Worm, Random Constant Spreading, Dynamic Network, Depth Distribution Characteristic, Bandwidth Control
Show / Hide AbstractEver since the network-based malicious code commonly known as a 'worm' surfaced in the early part of the 1980's, its prevalence has grown more and more. The RCS (Random Constant Spreading) worm has become a dominant, malicious virus in recent computer networking circles. The worm retards the availability of an overall network by exhausting resources such as CPU capacity, network peripherals and transfer bandwidth, causing damage to an uninfected system as well as an infected system. The generation and spreading cycle of these worms progress rapidly. The existing studies to counter malicious code have studied the Microscopic Model for detecting worm generation based on some specific pattern or sign of attack, thus preventing its spread by countering the worm directly on detection. However, due to zero-day threat actualization, rapid spreading of the RCS worm and reduction of survival time, securing a security model to ensure the survivability of the network became an urgent problem that the existing solution-oriented security measures did not address. This paper analyzes the recently studied efficient dynamic network. Essentially, this paper suggests a model that dynamically controls the RCS worm using the characteristics of Power-Law and depth distribution of the delivery node, which is commonly seen in preferential growth networks. Moreover, we suggest a model that dynamically controls the spread of the worm using information about the depth distribution of delivery. We also verified via simulation that the load for each node was minimized at an optimal depth to effectively restrain the spread of the worm.