14922920
A dynamic trust model for mobile ad hoc networks
This paper introduces a trust model for mobile ad hoc networks. Initially each node is assigned a trust level. Then we use several approaches to dynamically update trust levels by using reports from threat detection tools, such as intrusion detection systems (IDS), located on all nodes in the network. The nodes neighboring to a node exhibiting suspicious behavior initiate trust reports. These trust reports are propagated through the network using one of our proposed methods. A source node can use the trust levels it establishes for other nodes to evaluate the security of routes to destination nodes. Using these trust levels as a guide, the source node can then select a route that meets the security requirements of the message to be transmitted. This paper demonstrates important concepts for establishing a collaborative, dynamic trust model and for using this model as an example to enhance the security of message routing in mobile ad hoc networks.
242170
Active security support for active networks
Active networks aim to provide a software framework that enables network applications to customize the processing of their communication packets. Security is of critical importance to the success of active networking. This paper presents a design and a description of the implementation for securing the node of an active network using active networking principles. The secure node architecture includes an active node operating system security API, an active security guardian, and quality of protection (QoP) provisions. The architecture supports highly customized and situational policies created by users and applications dynamically. It permits active nodes to satisfy the application-specific dynamic security and protection requirements. The secure node architecture can provide a fundamental base for securing the active network infrastructure. We describe the integration of secure node architecture into an active network software system to demonstrate its flexible and innovative features.
20897828
A Formal Definition for Trust in Distributed Systems
Trust is an important concept in distributed computing environments and plays a critical role in ensuring and enhancing system security. Although various trust models have been proposed for distributed or pervasive computing systems, little research has been conducted to describe trust in precise and formal way. In this paper, we present a formal definition to express the meaning of trust in distributed computing systems. With this definition, we rigorously analyze the important properties of trust relation, such as reflexivity and conditional transitivity, and describe the trust relations in Role-Based Access Control. Our definition is comprehensive in that the semantic meaning of the trust definition is feasible to describe trust relations in both traditional distributed systems and dynamic pervasive computing environments. This research provides a solid base for formal trust reasoning and effective trust management implementation in distributed systems and pervasive computing environments.
27151074
Integrated Support for Location Aware Security Services in Enterprise Wireless Networks
In wireless computing environments limiting network access to authorized users is paramount for the overall security of network. In addition to basic authentication framework, network access is also governed by the context in which it is being used. In this work, we address security issues based on one such context: location. Location sensitivity is increasingly becoming an integral aspect of wireless and pervasive applications. As user moves around in an ubiquitous environment, access rights and other security services provided to her need to be evaluated accordingly. For such purposes we need a security mechanism that controls the authentication and other security services based on location, in addition to basic identity information. In this paper, we present an architecture of location aware security services for enterprise wireless networks. Our implementation is integrated into the RADIUS system, an Authentication, Authorization and Accounting (AAA) framework. Performace evaluation shows that our implementation is efficient for location based security services.
7088840
Communication protection in IP-based video surveillance systems
For decades, video surveillance systems have been crucial in protecting critical infrastructures. Currently the systems are adopting the emerging internetworking digital technology, changing from the traditional isolated analog technology. While there are several advantages of IP-based video surveillance systems, the systems are also exposed to additional new security threats. Security is a critical factor to make the IP-based video surveillance systems practical and usable. In this paper, we address the security threats to the data communications in IP-based video surveillance systems. We first analyze the current approaches, mainly naive and selective methods, to secure real-time video data, and identify their limitations to IP-based video surveillance systems. Then we propose a system design of secure internetworking video surveillance systems. Our proposed approach adopts a randomly adjustable encryption method to provide confidentiality to the data. Our implementation and performance study demonstrate that our approach achieves a good balance of cost-efficiency and security.
34025553
Security as services in active networks
This paper discusses the design and implementation for supporting customized security services in active networks using active networking principles. The customized security services support is based on a secure node architecture that includes an active node operating system security API, an active security guardian, and quality of protection provisions. The support of highly customized security services permits active nodes to satisfy the application-specific dynamic security and protection requirements. It associates quality of protection with network software and application security. Applications can dynamically select the suitable security configurations and services at each active routing node, based on their security and performance requirements. The secure node architecture, together with the support of dynamically customized security services, can provide a fundamental base for securing the active network infrastructure and active applications.
17293889
Complexity of Task Graph Scheduling with Fixed Communication Capacity
Consider a scheduling problem of parallel computations in multiprocessor systems. Let a parallel program be modeled by a task graph, where vertices represent tasks and arcs the communications between tasks. An interprocessor communication time incurs when two tasks assigned to two different processors have to communicate. Such a scheduling problem has recently been studied in the literature, mostly for the case where interprocessor communication times are fully determined. In this paper, we consider the scheduling problem with communication resource constraints. More specifically, we consider the case where all interprocessor communications take place on a network of bounded capacity. We consider two variants of the problem: communications with independent-data semantics and common-data semantics. We show that even for very specific subproblems, viz. scheduling of general graphs on two processors and scheduling of binary trees on an infinite number of processors, the minimization of the makespan of parallel programs in such a multiprocessor system is strongly -hard. We first establish the results for the case of capacity 1, referred to as the single-bus system. We then extend the results to the more general case of fixed communication capacities. As a consequence, the general scheduling problem of parallel programs with communication resource constraints is strongly -hard. These results are to be contrasted with the corresponding scheduling problems without contraint on the communication capacity, where the two-processor case has unknown time complexity and the infinite-processor case is polynomial. Our results are also extended to the case of broadcasting communications, and can be applied to multiprocessor systems with shared memory.
11533242
Multi-robot mobility enhanced hop-count based localization in ad hoc networks
The localization problem is important in mobile robots and wireless sensor network and has been studied for many years. Among many localization methods, the hop-count based approach is simple and scalable; however, the localization accuracy is not satisfactory if the node density is low. To solve this problem, in this paper a multi-robot approach is proposed to utilize the cooperation and mobility of the robots to improve the node distribution (density), thus enhancing the hop-count based localization. By an auction-based task allocation scheme, the robots can negotiate with the static sensor nodes and then select the most suitable robots to move to the area of sparse node density, thus increasing the localization accuracy for the static sensor nodes. On the other hand, the robots also can localize themselves with the help of the static sensor nodes. The efficacy of this approach is shown by simulation.
6770113
Image magnification method using joint diffusion
In this paper a new algorithm for image magnification is presented. Because linear magnification/interpolation techniques diminish the contrast and produce sawtooth effects, in recent years, many nonlinear interpolation methods, especially nonlinear diffusion based approaches, have been proposed to solve these problems. Two recently proposed techniques for interpolation by diffusion, forward and backward diffusion (FAB) and level-set reconstruction (LSR), cannot enhance the contrast and smooth edges simultaneously. In this article, a novel Partial Differential Equations (PDE) based approach is presented. The contributions of the paper include: firstly, a unified form of diffusion joining FAB and LSR is constructed to have all of their virtues; secondly, to eliminate artifacts of the joint diffusion, soft constraint takes the place of hard constraint presented by LSR; thirdly, the determination of joint coefficients, criterion for stopping time and color image processing are also discussed. The results demonstrate that the method is visually and quantitatively better than Bicubic, FAB and LSR.
207320245
Hidden Markov models with factored Gaussian mixtures densities
We present a factorial representation of Gaussian mixture models for observation densities in hidden Markov models (HMMs), which uses the factorial learning in the HMM framework. We derive the reestimation formulas for estimating the factorized parameters by the Expectation Maximization (EM) algorithm and propose a novel method for initializing them. To compare the performances of the proposed models with that of the factorial hidden Markov models and HMMs, we have carried out extensive experiments which show that this modelling approach is effective and robust.
6908345
A swarm intelligence routing algorithm for MANETs
This paper presents a novel swarm intelligence inspired routing algorithm (EARA) for mobile ad hoc networks. Based on the understanding of the evolutionary cooperation in the biological swarm, which provides an alternative solution resilient against changes in the dynamic environment, We use the principle of swarm intelligence for the reinforcement of optimal routes with only local communication (here, local communication is defined as neighbourto-neighbour one only). The data traffic is influenced at each node, and the communicating nodes observe this influence to update their tables. We also include an evaluation, and the simulation results show that this routing algorithm scales well to a variety of network conditions.