In our previous work, the limitation of standard type I and II power saving in IEEE 802.16e was discussed, and the idea of load-based power saving LBPS was proposed for better power-saving efficiency. LBPS measures traffic load and adaptively generates proper sleep schedule for the current load. Three LBPS schemes have been proposed for mobile subscriber station MSS power saving. In this paper, base station BS power saving is taken into consideration, and our previously proposed LBPS schemes, are extended and revised to integrate both BS and MSS in sleep scheduling. Two strategies of integrated power saving, MSS first and BS first, each with associated LBPS schemes are proposed in the paper. A three-staged concept combining the proposed strategies is also presented to make the best of integrated power saving. A simulation study shows that the proposed schemes can effectively achieve high power-saving efficiency for both BS and MSS. Copyright © 2013 John Wiley & Sons, Ltd.

Internet is growing very rapidly in both the size and the traffic. Routers with efficient IP lookup schemes are needed to handle the amount of traffic. The IP lookup scheme is a key issue in design of IP routers, which searches the next hop of each incoming packet with a longest prefix matching in routing table. This operation is complex and is a major bottleneck in a high performance router. In this paper, we propose a fast and updateable scheme for dynamic routing tables that can dynamically insert and delete prefixes. We adopt a compressed bitmap data structure for IP lookup and develop a prefix parent relationship data structure for dynamically update prefixes. The simulation reveals that our scheme has high performance in IP lookup, even using real IPv4 routing tables with large entries.

In this paper, we present a new and dependable disaster broadcasting network. The urgent information is broadcasted in the low-frequency band of 40-80kHz and modulated with reliable pulse width modulation(PWM). The coverage of one low-frequency broadcasting station is more than 500km. With excellent propagation characteristics, the low-frequency signal could penetrate into remote areas which are usually lack of telecommunication infrastructure. To promulgate the hazard information to general people of one specific area, the hierarchical data structure is proposed. A series of field measurement, test and theoretical comparisons are conducted to evaluate the performance of low-frequency system. It is shown from our experimental results that the low-frequency broadcasting network is a dependable and cost-effective solution in disaster management. Finally, a sustainable heterogeneous and layered ICT network designed for disaster management is drawn.

This paper presents a wireless sensor network approach for collecting rehabilitation data with exercising bilateral sanding units. Three wireless sensor nodes are attached to a conventional sanding unit for automatic data collections. Two wireless sensor nodes are desired for a set of sanding hand blocks, and the remaining one is used for the reciprocal exercise platform. Three wireless sensor nodes can be easily attached to conventional sanding units with less wiring and setup efforts for fast realizing data collection functions. Finally, a system prototype is produced in this project, and the bilateral accelerations, exercise strokes and gripping forces are also properly collected to validate our approaches.

k-Coterie is a useful concept to solve the distributed k-mutual exclusion problem. The distributed k-mutual exclusion algorithms based on k-coteries have benefits of the high fault-tolerance and the low message cost. Harada and Yamashita proposed a basic tree structure to construct tree k-coteries. When the root fails, quorums are degraded and their sizes grow rapidly. In this paper, we propose the general tree structure to construct general tree 1-coteries to reduce the degradation of quorums. In the general tree 1-coterie, the responsibility of the root to construct small quorums could be adjusted. When the root fails, the degradation of quorums could be reduced. Then, we propose the coterie root-join operation to construct general tree k-coteries by root-joining k general tree 1-coteries at a common root. In the general tree k-coterie, the degradation of quorums and the quorum size could be reduced at same time. We show that general tree k-coteries could be complemental. Thus, general tree k-coteries are resilient when the network is 2-partitioned.

k-Coterie is a graceful concept to solve the distributed k-mutual exclusion problem. The k-mutual exclusion algorithm adopting k-coteries could provide the fault-tolerant capability. The complementalness and the availability are two important metrics to measure the fault-tolerant capability of a k-coterie. Since those two metrics are defined under two different failure assumptions, for a given k-coterie, two independent works to measure those two metrics are necessary. In this paper, we derive the characteristics of the complemental k-coterie on its availability. With the characteristic, verifying the complementalness of a k-coterie and evaluating its availability could be combined together to reduce the redundant works on measuring the fault-tolerant capability of the k-coterie.

For original paper see Jiang, ibid., vol.53, p.922-923 (2004). Jiang shows a result that a Cohorts coterie is nondominated (ND) under a Cohorts structure Coh(k,n) = (C1,C2,..., Cn) if |C1| = k. However, the result is incorrect. In this comment, we correct the result by deriving the necessary and sufficient conditions for the Cohorts coterie to be ND. As we will see, a Cohorts coterie under Coh(k,n) is ND if and only if k = 1 or n = 1.

The k-arbiter is a useful concept to solve the distributed h-out-of-k mutual exclusion problem. The distributed h-out-of-k mutual exclusion algorithms, based on the k-arbiter, have the benefits of high fault tolerance and low message cost. However, according to the definition of the k-arbiter, it is required to have a nonempty intersection among any (/spl kappa/ + 1) quorums in a k-arbiter. Consequently, constructing k-arbiters is difficult. The coterie join operation proposed by Neilsen and Mizuno (1992) produces a new and larger coterie by joining known coteries. By extending the coterie join operation, we first propose a k-arbiter join operation to construct a new and larger k-arbiter from known k-arbiters for a large system. Then, we derive a necessary and sufficient condition for the k-arbiter join operation to construct a nondominated joined k-arbiter. Moreover, we discuss availability properties of the joined k-arbiters. We observe that, by selecting proper k-arbiters, the joined k-arbiter can provide a higher availability than that of the original input. Finally, we propose a k-arbiter compound, operation to construct k-arbiters by using coteries and/or k-coteries. By that way, the problem of constructing k-arbiters can be reduced to the problem of constructing coteries and/or k-coteries.

Coterie is a widely accepted concept for solving the mutual exclusion problem. Nondominated coteries are an important class of coteries which have better performance than dominated coteries. The performance of a coterie is usually measured by availability. Higher availability of a coterie exhibits greater ability to tolerate node or communication link failures. In this paper, we demonstrate a way to recognize nondominated coteries using availability. By evaluating the availability of a coterie instead of using a formal proof, the coterie can be recognized as a nondominated coterie or not. Moreover, with regard to wr-coterie, a concept for solving the replica control problem, we also present a similar result for recognizing nondominated wr-coteries. Finally, we apply our results to some well-known coteries and wr-coteries.

We propose a structure named Cohorts to solve the problem of the access control of multiple entries to a critical section. Our solution is formalized as forming quorums in a k-coterie. It is resilient to node failures and/or network partitioning, invokes constant expected message cost and has comparably high availability.

Quorum-based mutual exclusion algorithms are resilient to node and communication line failures. Recently, some mutual exclusion algorithms successfully use logical structures to construct coteries with small quorums sizes. In this paper, we introduce a geometric approach on dealing with the logical structures and present some useful geometric properties for constructing coteries and k-coteries. Based on those geometric properties, a logical structure named three-sided graph is proposed to provide a new scheme for constructing coteries with small quorums: The smallest quorum size is O(/spl radic/N) in a homogeneous system with N nodes and O(1) in a heterogeneous system. In addition, we also extend the three-sided graph to the O-sided graph for constructing k-coteries.

The authors extend the concept of coterie into k-coterie for k entries to a critical section. A structure named Cohorts is proposed to construct quorums in a k-coterie. The solution is resilient to node failures and/or network partitioning and has a low communication cost. The Cohorts structure is further improved to increase the availabilities of 1-entry critical sections.>