Wireless microsensor networks have been identified as one of the most important technologies for the 21st century. This paper traces the history of research in sensor networks over the past three decades, including two important programs of the Defense Advanced Research Projects Agency (DARPA) spanning this period: the Distributed Sensor Networks (DSN) and the Sensor Information Technology (SensIT) programs. Technology trends that impact the development of sensor networks are reviewed, and new applications such as infrastructure security, habitat monitoring, and traffic control are presented. Technical challenges in sensor network development include network discovery, control and routing, collaborative signal and information processing, tasking and querying, and security. The paper concludes by presenting some recent research results in sensor network algorithms, including localized algorithms and directed diffusion, distributed tracking in wireless ad hoc networks, and distributed classification using local agents.

/pdf/sensor-networks-evolution-opportunities-and-challenges-5donoenh95.pdf

Sensor networks: evolution, opportunities, and challenges

http://www.123seminarsonly.com/Seminar-Reports/015/53603449-zigbee.pdf

Wireless sensor networks: A survey on the state of the art and the 802.15.4 and ZigBee standards

This paper presents a systematic solution to the persistent problem of buffer overflow attacks. Buffer overflow attacks gained notoriety in 1988 as part of the Morris Worm incident on the Internet. While it is fairly simple to fix individual buffer overflow vulnerabilities, buffer overflow attacks continue to this day. Hundreds of attacks have been discovered, and while most of the obvious vulnerabilities have now been patched, more sophisticated buffer overflow attacks continue to emerge.

We describe StackGuard: a simple compiler technique that virtually eliminates buffer overflow vulnerabilities with only modest performance penalties. Privileged programs that are recompiled with the StackGuard compiler extension no longer yield control to the attacker, but rather enter a fail-safe state. These programs require no source code changes at all, and are binary-compatible with existing operating systems and libraries. We describe the compiler technique (a simple patch to gcc), as well as a set of variations on the technique that trade-off between penetration resistance and performance. We present experimental results of both the penetration resistance and the performance impact of this technique.

/pdf/stackguard-automatic-adaptive-detection-and-prevention-of-59g5hygw3s.pdf

StackGuard: automatic adaptive detection and prevention of buffer-overflow attacks

Internet hosting centers serve multiple service sites from a common hardware base. This paper presents the design and implementation of an architecture for resource management in a hosting center operating system, with an emphasis on energy as a driving resource management issue for large server clusters. The goals are to provision server resources for co-hosted services in a way that automatically adapts to offered load, improve the energy efficiency of server clusters by dynamically resizing the active server set, and respond to power supply disruptions or thermal events by degrading service in accordance with negotiated Service Level Agreements (SLAs).Our system is based on an economic approach to managing shared server resources, in which services "bid" for resources as a function of delivered performance. The system continuously monitors load and plans resource allotments by estimating the value of their effects on service performance. A greedy resource allocation algorithm adjusts resource prices to balance supply and demand, allocating resources to their most efficient use. A reconfigurable server switching infrastructure directs request traffic to the servers assigned to each service. Experimental results from a prototype confirm that the system adapts to offered load and resource availability, and can reduce server energy usage by 29% or more for a typical Web workload.

/pdf/managing-energy-and-server-resources-in-hosting-centers-2zu02bqt14.pdf

Managing energy and server resources in hosting centers

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

In this paper we propose changing the decades-old practice of allocating CPU to threads based on priority to a scheme based on proportion and period. Our scheme allocates to each thread a percentage of CPU cycles over a period of time, and uses a feedback-based adaptive scheduler to assign automatically both proportion and period. Applications with known require-ments, such as isochronous software devices, can bypass the adaptive scheduler by specifying their desired proportion and/or period. As a result, our scheme provides reservations to applica-tions that need them, and the benefits of proportion and period to applications that do not need reservations. Adaptive scheduling using proportion and period has several distinct benefits over either fixed or adaptive priority based schemes: finer grain control of allocation, lower variance in the amount of cycles allocated to a thread, and avoidance of accidental priority inversion and starvation, including defense against denial-of-service attacks. This paper describes our design of an adaptive controller and proportion-period scheduler, its implementation in Linux, and presents experimental validation of our approach.

/pdf/a-feedback-driven-proportion-allocator-for-real-rate-2nts8mupqp.pdf

A feedback-driven proportion allocator for real-rate scheduling

We describe Environmental Observation and Forecasting Systems (EOFS), a new class of large-scale distributed system designed to monitor, model, and forecast wide-area physical processes such as river systems. EOFS have strong social relevance in areas such as education, transportation, agriculture, natural resource planning and disaster response. In addition, they represent an opportunity for scientists to study large physical systems to an extent that was not previously possible. Building the next generation of EOFS pose a number of difficult challenges in all aspects of wireless networking, including media protocols for long distance vertical communication through water, flooding algorithms in ad-hoc network topologies, support for rate- and time-sensitive applications, and location-dependent mobile computing.

http://vega.cs.kent.edu/~mikhail/Download/Sensbuoy/Lit/p292-steere.pdf

Research challenges in environmental observation and forecasting systems

This paper describes the design and implementation of a real-time, streaming, Internet video and audio player. The player has a number of advanced features including dynamic adaptation to changes in available bandwidth, latency and latency variation; a multi-dimensional media scaling capability driven by user-specified quality of service (QoS) requirements; and support for complex content comprising multiple synchronized video and audio streams. The player was developed as part of the QUASAR project at Oregon Graduate Institute, is freely available, and serves as a testbed for research in adaptive resource management and QoS control.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

/pdf/player-for-adaptive-mpeg-video-streaming-over-the-internet-3bal9st8kv.pdf

Player for adaptive MPEG video streaming over the Internet

Specialization has been recognized as a powerful technique for optimizing operating systems. However, specialization has not been broadly applied beyond the research community because current techniques based on manual specialization, are time-consuming and error-prone. The goal of the work described in this paper is to help operating system tuners perform specialization more easily. We have built a specialization toolkit that assists the major tasks of specializing operating systems. We demonstrate the effectiveness of the toolkit by applying it to three diverse operating system components. We show that using tools to assist specialization enables significant performance optimizations without error-prone manual modifications. Our experience with the toolkit suggests new ways of designing systems that combine high performance and clean structure.

/pdf/specialization-tools-and-techniques-for-systematic-4bkrh31nvy.pdf

Specialization tools and techniques for systematic optimization of system software

CPU scheduling and admission testing for multimedia applications have been extensively studied, and various solutions have been proposed using assorted simplifying assumptions. However, we believe that the complexity and dynamic behavior of multimedia applications and systems make static solutions hard to apply in real-world situations. We are analyzing the difficulties that arise when applying the rate-monotonic (RM) scheduling algorithm and the corresponding admission tests for CPU management, in the context of real multimedia applications running on real systems. RM requires statically predictable, periodic workloads, and while multimedia applications appear to be periodic, in practice they exhibit numerous variabilities in workload. Our study suggests the need for more adaptive scheduling mechanisms, which would allow complex applications to dynamically respond to variations in workload and resource availability. Furthermore, we believe there is a need for a more abstract characterization of applications and resources for admission testing purposes. We conclude that adaptive CPU scheduling policies should address the needs of CPU scheduling and reservation for current multimedia applications.

/pdf/multimedia-applications-require-adaptive-cpu-scheduling-3ywstp8cq6.pdf

Dylan McNamee

Papers

A feedback-driven proportion allocator for real-rate scheduling

Research challenges in environmental observation and forecasting systems

Player for adaptive MPEG video streaming over the Internet

Specialization tools and techniques for systematic optimization of system software

Multimedia Applications Require Adaptive CPU Scheduling