15648291
An improved key distribution mechanism for large-scale hierarchical wireless sensor networks
Abstract Wireless sensor networks are often deployed in hostile environments and operated on an unattended mode. In order to protect the sensitive data and the sensor readings, secret keys should be used to encrypt the exchanged messages between communicating nodes. Due to their expensive energy consumption and hardware requirements, asymmetric key based cryptographies are not suitable for resource-constrained wireless sensors. Several symmetric-key pre-distribution protocols have been investigated recently to establish secure links between sensor nodes, but most of them are not scalable due to their linearly increased communication and key storage overheads. Furthermore, existing protocols cannot provide sufficient security when the number of compromised nodes exceeds a critical value. To address these limitations, we propose an improved key distribution mechanism for large-scale wireless sensor networks. Based on a hierarchical network model and bivariate polynomial-key generation mechanism, our scheme guarantees that two communicating parties can establish a unique pairwise key between them. Compared with existing protocols, our scheme can provide sufficient security no matter how many sensors are compromised. Fixed key storage overhead, full network connectivity, and low communication overhead can also be achieved by the proposed scheme.
18245224
Distributed Pairwise Key Establishment in Wireless Sensor Networks
Abstract - Security is a big challenge when wireless sensor networks are deployed in a hostile environment. Due to the computational and storage overheads, traditional asymmetric-key based security protocols are not suitable for the resource-constrained wireless sensors. Several symmetric-key distribution protocols have been proposed in literature to establish shared cryptographic keys between sensor nodes, but most of them only work for small-scale networks due to their linearly increased communication overhead and key storage overhead. Furthermore, existing protocols are not secure when the number of compromised nodes exceeds a threshold value. In this paper, we propose a new distributed pairwise key establishment method for large-scale wireless sensor networks. Compared with existing key distribution protocols, our scheme guarantees any two sensors to establish a pairwise key between them with low overheads. A high level network security also can be achieved in our scheme even a large number of sensors are compromised.
59852137
Energy Efficient Session Key Establishment in Wireless Sensor Networks
Key distribution and management is the foundation of any secure services of wireless sensor networks. Due to the resource constraints, establishing cryptographic keys between communicating sensors in large-scale wireless sensor networks is a big challenge. Traditional asymmetric key cryptography is not suitable for wireless sensor environment because of its complexity. Based on the polynomial-key pre-distribution scheme, an improved session key establishment method is proposed in this paper. Compared with existing key distribution schemes, our proposed scheme has lower energy consumption, less key storage and lower communication overheads as well as better network resilience against node capture attacks.
40703514
On weakly symmetric graphs of order twice a prime
Abstract A graph is weakly symmetric if its automorphism group is both vertex-transitive and edge-transitive. In 1971, Chao characterized all weakly symmetric graphs of prime order and showed that such graphs are also transitive on directed edges. In this paper we determine all weakly symmetric graphs of order twice a prime and show that these graphs too are directed-edge transitive.
3320962
Track seeking hybrid fuzzy controller for the compact disc player
A hybrid track seeking fuzzy controller for an optical compact disc player is proposed. It is shown that the proposed hybrid fuzzy controller smoothes the applied voltage to the sled motor and improves the track seeking efficiency. The proposed hybrid fuzzy controller consists of three subsystems including parking time controller, driving force controller and parameter tuner. All three of subsystems are designed based on fuzzy inference. The hybrid fuzzy controller will on one hand drive the pickup head as fast as possible to the neighborhood of target track, it will on the other hand smoothly park the pickup head so that the fine seek controller can take over the control of pickup head.
28212950
Life is sharable: blogging life experience with RFID embedded mobile phones
Recent development and proliferation of mobile devices, wireless communication, and sensor technologies have prompted a new vision of social interactions in the world in which we inhabit. For example, the number of mobile phones that are capable of capturing users' spontaneous life experiences not only in pictures but also in audio and video clips is on the increase. In addition, captured experiences can be sent and shared with others over wireless networks such as WiFi, GSM, GPRS, EDGE, or recently commenced third-generation (3G) protocols. Other technology trends such as weblog and peer-to-peer communication provide a ubiquitous platform and a model of motivating users to share life experiences with other people. The hypothesis is that everyone can be an owner of a weblog which records their experience about place, people, and things that interest them. Initial form of peer-to-peer communication, centralized directory service, can help authors of weblogs attain widespread of popularity and increase the level of participation in this type of interaction. The convergence of these technologies provides new design opportunities for computer-mediated communications. The aim of this paper is to share our experiences in designing and implementing a novel physical prototype which incorporates peer-to-peer communication, weblog, RFID, wireless networking, and mobile phone technologies to enhance social quality of shared life experience.
44320241
Convergence and Ordering of Kohonen's Batch Map
The convergence and ordering of Kohonen's batch-mode self-organizing map with Heskes and Kappen's (1993) winner selection are proved. Selim and Ismail's (1984) objective function for k-means clustering is generalized in the convergence proof of the self-organizing map. It is shown that when the neighborhood relation is doubly decreasing, order in the map is preserved. An unordered map becomes ordered when a degenerate state of ordering is entered, where the number of distinct winners is one or two. One strategy to enter this state is to run the algorithm with a broad neighborhood relation.
15761102
Dynamic inter-SLA resource sharing in path-oriented differentiated services networks
This paper proposes novel resource sharing schemes for differentiated services (DiffServ) networks, to achieve both high resource utilization and quality of service (QoS) guarantee. Service level agreements (SLAs) are negotiated at network boundaries and supported by path-oriented resource mapping within the network. The recently proposed SLA management scheme based on virtual partitioning (Bouillet et al., 2002) allows overloaded SLAs to exploit the spare capacity of underloaded SLAs for efficient resource utilization, however, at the the cost of possible SLA violation of the underloaders. In the bandwidth borrowing scheme proposed here, the dedicated bandwidth for underloaded SLAs is determined and adaptively adjusted at network boundaries according to the actual traffic load and QoS policies; the available spare capacity is then properly distributed to related links for lending to others. On the other hand, the traffic flows admitted with borrowed bandwidth are tagged and may be preempted later when the original bandwidth owner needs to claim back the resources. Through a detailed implementation design and extensive computer simulation results we show that, by bandwidth borrowing, both SLA compliance and high resource utilization can be achieved in various load conditions, with some side benefits such as call-level service differentiation, small admission overhead, and convenience for policy-based management. In addition, we propose a distributed bandwidth pushing scheme that can dynamically adjust the spare bandwidth distribution over the network. Combining bandwidth pushing with bandwidth borrowing, the resource utilization can be further improved