Data Mining - Concepts and Techniques.

Data Mining Practical Machine Learning Tools and Techniques

Topology control in a sensor network balances load on sensor nodes and increases network scalability and lifetime. Clustering sensor nodes is an effective topology control approach. We propose a novel distributed clustering approach for long-lived ad hoc sensor networks. Our proposed approach does not make any assumptions about the presence of infrastructure or about node capabilities, other than the availability of multiple power levels in sensor nodes. We present a protocol, HEED (Hybrid Energy-Efficient Distributed clustering), that periodically selects cluster heads according to a hybrid of the node residual energy and a secondary parameter, such as node proximity to its neighbors or node degree. HEED terminates in O(1) iterations, incurs low message overhead, and achieves fairly uniform cluster head distribution across the network. We prove that, with appropriate bounds on node density and intracluster and intercluster transmission ranges, HEED can asymptotically almost surely guarantee connectivity of clustered networks. Simulation results demonstrate that our proposed approach is effective in prolonging the network lifetime and supporting scalable data aggregation.

/pdf/heed-a-hybrid-energy-efficient-distributed-clustering-4c3cjgsfv9.pdf

HEED: a hybrid, energy-efficient, distributed clustering approach for ad hoc sensor networks

http://cpham.perso.univ-pau.fr/ENSEIGNEMENT/PAU-UPPA/RESA-M2/Clustering-abasi.pdf

A survey on clustering algorithms for wireless sensor networks

Topology Control (TC) is one of the most important techniques used in wireless ad hoc and sensor networks to reduce energy consumption (which is essential to extend the network operational time) and radio interference (with a positive effect on the network traffic carrying capacity). The goal of this technique is to control the topology of the graph representing the communication links between network nodes with the purpose of maintaining some global graph property (e.g., connectivity), while reducing energy consumption and/or interference that are strictly related to the nodes' transmitting range. In this article, we state several problems related to topology control in wireless ad hoc and sensor networks, and we survey state-of-the-art solutions which have been proposed to tackle them. We also outline several directions for further research which we hope will motivate researchers to undertake additional studies in this field.

/pdf/topology-control-in-wireless-ad-hoc-and-sensor-networks-3e17u396zt.pdf

Topology Control in Wireless Ad Hoc and Sensor Networks

Future broadband satellite networks will support a variety of service types. Many such systems are being design with ATM or ATM-like technology. A majority of Internet applications use TCP for data transfer. As a result, these systems must efficiently transport TCP traffic and provide service guarantees to such traffic. Several mechanisms have been presented in recent literature to improve TCP performance. Most of these can be categorized as either TCP enhancements or network-based buffer management techniques. Providing minimum rate guarantees to TCP traffic has also been suggested as a way to improve its performance in the presence of higher priority traffic sharing the link. However, the relative performance of the TCP enhancements versus the buffer management schemes has not been analyzed for long latency networks. In this paper, we address three issues. First, we present a performance analysis of TCP over satellite-ATM links using a best effort service—the ATM unspecified bit rate (UBR) service. This analysis shows that the relative impacts of buffer management, TCP policies and rate guarantees on TCP performance, depend heavily on the latency of the network. Second, we show through simulations that the buffer size required in the network for high TCP performance is proportional to the delay-bandwidth product of the network. Third, we propose a buffer management scheme called differential fair buffer allocation (DFBA) and show how it is used to implement a service that provides minimum rate guarantees to TCP traffic. An example of such a service is the ATM guaranteed frame rate (GFR) service, which is being standardized by the ATM Forum and the ITU. Copyright © 2001 John Wiley & Sons, Ltd.

https://www.cse.wustl.edu/~jain//papers/ftp/sat_journal.pdf

Buffer management and rate guarantees for TCP over satellite-ATM networks†

We extend our earlier studies of buffer requirements of TCP over ABR in two directions. First, we study the performance of TCP over ABR in an ATM backbone. On the backbone, the TCP queues are at the edge router and not inside the ATM network. The router requires buffer equal to the sum of the receiver window sizes of the participating TCP connections. Second, we introduce various patterns of VBR background traffic. The VBR background introduces variance in the ABR capacity and the TCP traffic introduces variance in the ABR demand. Some simple switch schemes are unable to keep up with the combined effect of highly varying demands and highly varying ABR capacity. We present our experiences with refining the ERICA+ switch scheme to handle these conditions.

Performance of TCP over ABR on ATM backbone and with various VBR traffic patterns

ABR Switch Algorithm Testing: A Case Study with ERICA

We study the sleep/wake scheduling problem in the context of clustered sensor networks. We conclude that the design of any sleep/wake scheduling algorithm must take into account the impact of the synchronization error. Our work includes two parts. In the first part, we show that there is an inherent tradeoff between energy consumption and message delivery performance (defined as the message capture probability in this work). We formulate an optimization problem to minimize the expected energy consumption, with the constraint that the message capture probability should be no less than a threshold. In the first part, we assume the threshold is already given. However, by investigating the unique structure of the problem, we transform the non-convex problem into a convex equivalent, and solve it using an efficient search method. In the second part, we remove the assumption that the capture probability threshold is already given, and study how to decide it to meet the quality of services (QoS) requirement of the application. We observe that in many sensor network applications, a group of sensors collaborate to perform common task(s). Therefore, the QoS is usually not decided by the performance of any individual node, but by the collective performance of all the related nodes. To achieve the collective performance with minimum energy consumption, intuitively we should provide differentiated services for the nodes and favor more important ones. We thus formulate an optimization problem, which aims to set the capture probability threshold for messages from each individual node such that the expected energy consumption is minimized, while the collective performance is guaranteed. The problem turns out to be non-convex and hard to solve exactly. Therefore, we use approximation techniques to obtain a suboptimal solution that approximates the optimum. Simulations show that our approximate solution significantly outperforms a scheme without differentiated treatment of the nodes.

/pdf/optimal-qos-aware-sleep-wake-scheduling-for-time-35u69c1nar.pdf

Optimal QoS-aware Sleep/Wake Scheduling for Time-Synchronized Sensor Networks

The ATM guaranteed frame rate (GFR) service is intended for best effort traffic that can benefit from minimum throughput guarantees. Edge devices connecting LANs to an ATM network can use GFR to transport multiple TCP/IP connections over a single GFR VC. These devices would typically multiplex VCs into a single FIFO queue. It has been shown that in general, FIFO queuing is not sufficient to provide rate guarantees, and per-VC queuing with scheduling is needed. We show that under conditions of low buffer allocation, it is possible to control TCP rates with FIFO queuing and buffer management. We present analysis and simulation results on controlling TCP rates by buffer management. We present a buffer management policy that provides loose rate guarantees to SACK TCP sources when the total buffer allocation is low. We study the performance of this buffer management scheme by simulation.

https://www.cs.wustl.edu/~jain/papers/ftp/lcn98.pdf

Sonia Fahmy

Papers

Buffer management and rate guarantees for TCP over satellite-ATM networks†

Performance of TCP over ABR on ATM backbone and with various VBR traffic patterns

ABR Switch Algorithm Testing: A Case Study with ERICA

Optimal QoS-aware Sleep/Wake Scheduling for Time-Synchronized Sensor Networks

Providing rate guarantees to TCP over the ATM GFR service