5315254
Efficient and Secure Authentication Protocols for Mobile VoIP Communications
Mobile Voice over IP (Mobile VoIP) allows mobile users to continuously talk with each others while roaming across different networks. In such wireless application, it is vulnerable to information security. In this paper, we present two efficient and secure authentication protocols for mobile VoIP services. In our approaches, we first develop a secure authentication protocol for mobile IP registration procedure. And then, based on this authenticated process, we extend the similar concept to a SIP-based VoIP service, and thus propose the second simple and secure communication protocol. For verifying our contributions, we demonstrate our proposed protocols secure and efficient: (1) by conducting security analysis on the aspects of data integrity, confidentiality, and several common network attacks, such as replay, man-in-the-middle; and (2) by conducting simulations and showing comparison results with other existing protocols, in terms of the communication and computation overheads imposed on the mobile node. All results point out that our protocols are superior to others.
46410326
A Platform Implementation for Real Time Image Processing
The technologies for image processing are improved evidently since the popularity of modern IA products in the last decade. In order to satisfy the needs on high quality images, higher contrast, higher saturation and higher resolution become the main goals of the researches. This article focuses on how to implement a platform for real time image processing to provide a realistic environment for developing techniques on enhancing image contrast dynamically in real time. A new method for improving the contrast quality of images can be verified by feeding analog images of NTSC television to this platform after digitalized, then perform the functions of enhancing image contrast by FPGA to provide the enhanced result of image contrast. It's different from the simulations made by software that proposed by the past researches, this article proposes a practical hardware real time processing foundation that can be used as a valuable reference of real time image processing.
23743946
Automatic pectoral muscle boundary detection in mammograms based on Markov chain and active contour model
Automatic pectoral muscle removal on medio-lateral oblique (MLO) view of mammogram is an essential step for many mammographic processing algorithms. However, it is still a very difficult task since the sizes, the shapes and the intensity contrasts of pectoral muscles change greatly from one MLO view to another. In this paper, we propose a novel method based on a discrete time Markov chain (DTMC) and an active contour model to automatically detect the pectoral muscle boundary. DTMC is used to model two important characteristics of the pectoral muscle edge, i.e., continuity and uncertainty. After obtaining a rough boundary, an active contour model is applied to refine the detection results. The experimental results on images from the Digital Database for Screening Mammography (DDSM) showed that our method can overcome many limitations of existing algorithms. The false positive (FP) and false negative (FN) pixel percentages are less than 5% in 77.5% mammograms. The detection precision of 91% meets the clinical requirement.
14309178
A New Rights Processing Method for DRM Systems
There are many solutions and standards about digital rights management(DRM) now. Almost all the solutions used cryptography and rights processing technologies to protect contents. Only legal users can decrypt and enjoy contents under the control of rights information, illegal users are prohibited. Rights processing technologies include rights expression languages (REL), binary encoding method, virtual machine, and so on. ODRL (Open Digital Rights Language) and XrML (eXtensible Markup Language) are all RELs, which express rights based on XML. Broadcasting flag encodes copy control information into binary data block. Marlin DRM uses Plankton virtual machine to process rights information. In this paper, we provided a rights processing method which is based on ASN.1(Abstract Syntax Notation One) syntax and using ASN.1 distinguishable encoding rule (DER) to encode rights information into binary data block. Compared with RELs, this rights processing method uses less bits to express rights information and can save more bandwidth during transmission. And it can express more rights information than broadcast flag.
23948133
Building Domain Ontology Based on Web Data and Generic Ontology
The automatic or semi-automatic construction of ontology has become a research topic of interest in recent years. This paper describes a mechanism for constructing domain specific ontologies automatically based on web data and generic ontology. Firstly, we employ the hierarchical agglomerative clustering(HAC) algorithm, clustering web pages hierarchically and resulting in a binary tree. Then an algorithm is proposed, which selectd from the binary tree the significative nodes as topics implying concepts of domain interests. Lastly, the Chinese generic ontology, HowNet, is introduced to evolve the topics (together with their hierarchical structures) into domain ontology. We experiment our method in the field of computer hardware based on web pages collected from Chinese BtoC web sites. An in-depth discussion on the experiment results is also given.
5908339
Intelligent Hierarchical Intrusion Detection System for Secure Wireless Ad Hoc Network
The nature of mobile ad hoc network (MANETs) makes them vulnerable to security attacks. Intrusion detection is a vital secure scheme for wireless mobile ad hoc networks (MANETs). However, the generalizing ability of current IDS is poor when given less priori knowledge, and a centralized intrusion detection network security solution does not work well in MANETs. In this paper we discuss the characters of security issues in ad hoc networks and propose a Support Vector Machine (SVM) based distributed hierarchical intrusion detection system that adapt to the characters of current ad hoc networks. Performance evaluations based on simulation experiment manifested our proposed approach is efficient and effective.
17936922
A call admission control scheme for packet data in CDMA cellular communications
In wireless cellular communication systems, call admission control (CAC) is to ensure satisfactory services for mobile users and maximize the utilization of the limited radio spectrum. In this paper, we propose a new CAC scheme for a code division multiple access (CDMA) wireless cellular network supporting heterogeneous self-similar data traffic. In addition to ensuring transmission accuracy at the bit level, the CAC scheme guarantees service requirements at both the call level and the packet level. The grade of service (GoS) at the call level and the quality of service (QoS) at the packet level are evaluated using the handoff call dropping probability and the packet transmission delay, respectively. The effective bandwidth approach for data traffic is applied to guarantee QoS requirements. Handoff probability and cell overload probability are derived via the traffic aggregation method. The two probabilities are used to determine the handoff call dropping probability, and the GoS requirement can be guaranteed on a per call basis. Numerical analysis and computer simulation results demonstrate that the proposed CAC scheme can meet both QoS and GoS requirements and achieve efficient resource utilization.