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.
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.
10297562
Computational Models for the Helix Tilt Angle
The concept of hydrophobic imbalance and that of hydrophobic and hydrophilic centers are used along with side chain models in the computation of helix orientation and tilt angle in or near a membrane. Rotamer statistics are used to infer typical side chain positions and chain length for each amino acid, and the results are used in fast computation of helix orientation. Sliding windows are used to compute local tilt angles on long alpha-helices that defy idealized modeling and generate tilt angle profiles. Seven different procedures based on different formulas and hydrophobicity scales are used for comparison. These procedures generated very similar tilt angle profiles. These profiles provide insights into helix deformation, membrane destabilization, and similarity and differences between membrane proteins.
6228406
Distributed and parallel execution of Java programs on a DSM system
The paper focuses on the loop-level parallelism of bytecode on a distributed shared memory (DSM) system, which is built on a cluster of multiprocessors. We define a new attribute called 'Loop Attribute' to record the information of Java loops. When first loading a Java program, our Java virtual machine, called ES-JVM, checks and analyzes the loops of the bytecode dynamically, handles the data dependence of loops, and records the information as the loop attributes. ES-JVM uses the virtual shared memory and synchronization mechanisms provided by the DSM system to maintain the memory consistency. Before ES-JVM interprets the loops of the bytecodes, it dispatches the workload of loops to the interpreter threads at all nodes according to the loop attributes and the number of threads. After distributed and parallel execution of the loops, ES-JVM continues to interpret the rest of the bytecodes of the Java program. Finally, ES-JVM saves the loop attributes in a new class file for the next run. Our research shows that distributed and parallel execution of loops of a Java program could improve performance.
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
6321522
Biclustering of Expression Data
An efficient node-deletion algorithm is introduced to find submatrices in expression data that have low mean squared residue scores and it is shown to perform well in finding co-regulation patterns in yeast and human. This introduces "biclustering", or simultaneous clustering of both genes and conditions, to knowledge discovery from expression data. This approach overcomes some problems associated with traditional clustering methods, by allowing automatic discovery of similarity based on a subset of attributes, simultaneous clustering of genes and conditions, and overlapped grouping that provides a better representation for genes with multiple functions or regulated by many factors.
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.