Appearing in 1st IEEE International Workshop on Sensor Net Protocols and Applications (SNPA). Anchorage, Alaska, USA. May 11, 2003. RMST: Reliable Data Transport in Sensor Networks Fred Stann, John Heidemann Abstract – Reliable data transport in wireless sensor networks is a multifaceted problem influenced by the physical, MAC, network, and transport layers. Because sensor networks are subject to strict resource constraints and are deployed by single organizations, they encourage revisiting traditional layering and are less bound by standardized placement of services such as reliability. This paper presents analysis and experiments resulting in specific recommendations for implementing reliable data transport in sensor nets. To explore reliability at the transport layer, we present RMST (Reliable Multi- Segment Transport), a new transport layer for Directed Diffusion. RMST provides guaranteed delivery and fragmentation/reassembly for applications that require them. RMST is a selective NACK-based protocol that can be configured for in-network caching and repair. Second, these energy constraints, plus relatively low wireless bandwidths, make in-network processing both feasible and desirable [3]. Third, because nodes in sensor networks are usually collaborating towards a common task, rather than representing independent users, optimization of the shared network focuses on throughput rather than fairness. Finally, because sensor networks are often deployed by a single organization with inexpensive hardware, there is less need for interoperability with existing standards. For all of these reasons, sensor networks provide an environment that encourages rethinking the structure of traditional communications protocols. The main contribution is an evaluation of the placement of reliability for data transport at different levels of the protocol stack. We consider implementing reliability in the MAC, transport layer, application, and combinations of these. We conclude that reliability is important at the MAC layer and the transport layer. MAC-level reliability is important not just to provide hop-by-hop error recovery for the transport layer, but also because it is needed for route discovery and maintenance. (This conclusion differs from previous studies in reliability for sensor nets that did not simulate routing. [4]) Second, we have developed RMST (Reliable Multi-Segment Transport), a new transport layer, in order to understand the role of in- network processing for reliable data transfer. RMST benefits from diffusion routing, adding minimal additional control traffic. RMST guarantees delivery, even when multiple hops exhibit very high error rates. 1 Introduction Wireless sensor networks provide an economical, fully distributed, sensing and computing solution for environments where conventional networks are impractical. This paper explores the design decisions related to providing reliable data transport in sensor nets. The reliable data transport problem in sensor nets is multi-faceted. The emphasis on energy conservation in sensor nets implies that poor paths should not be artificially bolstered via mechanisms such as MAC layer ARQ during route discovery and path selection [1]. Path maintenance, on the other hand, benefits from well- engineered recovery either at the MAC layer or the transport layer, or both. Recovery should not be costly however, since many applications in sensor nets are impervious to occasional packet loss, relying on the regular delivery of coarse-grained event descriptions. Other applications require loss detection and repair. These aspects of reliable data transport include the provision of guaranteed delivery and fragmentation/ reassembly of data entities larger than the network MTU. Sensor networks have different constraints than traditional wired nets. First, energy constraints are paramount in sensor networks since nodes can often not be recharged, so any wasted energy shortens their useful lifetime [2]. This work was supported by DARPA under grant DABT63-99-1-0011 as part of the SCAADS project, and was also made possible in part due to support from Intel Corporation and Xerox Corporation. Fred Stann and John Heidemann are with USC/Information Sciences Institute, 4676 Admiralty Way, Marina Del Rey, CA, USA E-mail: fstann@usc.edu, johnh@isi.edu. 2 Architectural Choices There are a number of key areas to consider when engineering reliability for sensor nets. Many current sensor networks exhibit high loss rates compared to wired networks (2% to 30% to immediate neighbors)[1,5,6]. While error detection and correction at the physical layer are important, approaches at the MAC layer and higher adapt well to the very wide range of loss rates seen in sensor networks and are the focus of this paper. MAC layer protocols can ameliorate PHY layer unreliability, and transport layers can guarantee delivery. An important question for this paper is the trade off between implementation of reliability at the MAC layer (i.e. hop to hop) vs. the Transport layer, which has traditionally been concerned with end-to-end reliability. Because sensor net applications are distributed, we also considered implementing reliability at the application layer. Our goal is to minimize the cost of repair in terms of transmission.

RMST: Reliable Data Transport in Sensor Networks

primary longman elect, longman elect js2b answer librarydoc31 pdf slideblast com, products amp services summary pearson hk, nss longman economics question bank smalanchealriff, longman elect nss companion website, longman activate nss complete exam practice answer for the, longman elect nss mock paper 1 answer pdf predsopmentfast, longman elect complete exam practice for hkdse answer key, longman elect js1 3 companion website, mmis basic search cd rom database hong, nss exam series 2010 pearson hk mafiadoc com, all elt products amp services in hong kong longman english, longman activate nss complete exam practice answer for the, english language pearson, answer keys longman elect senior secondary companion website, longman elect nss mock paper 1 answer pdf plyfelin, longman elect complete exam practice for hkdse answer key, longman elect nss companion website, free download here, longman elect exam practice answer set 1, longman elect nss complete exam practice answerrar, longman elect nss answer set 3 pdf slideblast com, nss longman economics question bank lufebcater wixsite com, longman elect nss writing skills book asset 1 soup io, longman elect nss mock paper 1 answer pdf kontmandiapa, mydselab english language longman elect senior secondary, longman activate nss complete exam practice answer for the, longman elect senior secondary companion website, exam practice hkdse answer set 2 faroush org, longman elect nss mock paper 1 answer pdf, longman activate nss complete exam practice answer for theenriching english language teaching amp learning for the new generation primary english seminar amp school cases sharing, get longman elect nss answer set 3 pdf file for free on our ebook library public sector governance and accountability logic programming first russian longman academic series 2 answer keys librarydoc31 pdf librarydoc31 lipstick traces a secret history of the twentieth century greil marcus librarydoc31 logic and design revised in art, brief description the longman elect new senior secondary theme book is a brand new task based coursebook specially designed to meet the aims of the new senior secondary nss english language curriculum for secondary 4 to 6 building on the solid foundation of knowledge skills values and attitudes laid down in the widely successful longman elect junior secondary series the longman elect, question bank update for book 1b chapter 8 10 are available 2 3 2012 supplementary exercises for book 2a ch 1 3 are available 20 02 2012 longman elect exam practice answer set 1 pdf free download here pearson longman nss exam series 2010 question answer book p nss bafs business environment introduction to ma question bank 1 1, welcome to the longman elect nss companion website the online assessment centre oac is now available with selected content click the oac icon below to access it this site is best viewed at 1024x768 screen resolution with chrome 24 firefox 20 or internet explorer 9 legal, 7b042e0984 download and read longman activate nss complete exam practice for the hkdse answer longman activate nss complete exam practice for the hkdse answer ebooks prentice hall geometry 4 3 practice answers longman activate nss complete exam practice for the 4 3 practice answers free download, longman elect nss mock paper 1 answer pdf gt download mirror 1 e31cf57bcd nike inc pdf online longman elect exam practice answer set 6 english nss exam longman elect exam practice answer answer keys sets 1 8 extra set 6 papers get longman reading anthology 5 answer pdf file

私の computer 環境

Fault-Tolerant Computer System Design by Dhiraj K. Pradhan 550 pp. $72 Prentice Hall Upper Saddle River, N.J. 1996 ISBN 0-13-057887-8

Fault-tolerant computer system design

Perception layer security in Internet of Things

Remaining useful lifetime prediction and extension of Si power devices have been studied extensively. Silicon carbide (SiC) power devices have been developed and commercialized. Specifically, SiC mosfet s have been utilized for the next generation high-voltage, high-power converters with smaller size and higher efficiency, covering various mainstream applications, including photovoltaic systems, electric vehicles, solid-state transformers, and more electric ships and airplanes. However, the SiC-based devices have different failure modes and mechanisms compared with Si counterparts. Therefore, a comprehensive review is critical to develop accurate lifetime prediction and extension strategies for SiC power converter systems. The SiC power device component-level failure modes and mechanisms are first investigated. Different accelerated lifetime tests and component-level lifetime models are then compared. Power converter system-level offline lifetime modeling techniques and software tools are further summarized. Besides, the SiC power converter condition monitoring strategies and health indicators are surveyed. The online measurement challenges are also studied. Furthermore, the system-level lifetime extension strategies are reviewed. By integrating device physics, statistical modeling, reliability engineering, and mechanical engineering with power electronics, this article is intended to provide a comprehensive overview, address existing challenges, and unfold new research opportunities regarding the SiC power converter real-time lifetime prediction and extension.

Overview of Real-Time Lifetime Prediction and Extension for SiC Power Converters

Reliability modeling and analysis of communication networks

Formalization of Reliability Block Diagrams in Higher-order Logic

It is customary to assess the reliability of underground oil and gas pipelines in the presence of excessive loading and corrosion effects to ensure a leak-free transport of hazardous materials. The main idea behind this reliability analysis is to model the given pipeline system as a Reliability Block Diagram (RBD) of segments such that the reliability of an individual pipeline segment can be represented by a random variable. Traditionally, computer simulation is used to perform this reliability analysis but it provides approximate results and requires an enormous amount of CPU time for attaining reasonable estimates. Due to its approximate nature, simulation is not very suitable for analyzing safety-critical systems like oil and gas pipelines, where even minor analysis flaws may result in catastrophic consequences. As an accurate alternative, we propose to use a higher-order-logic theorem prover (HOL) for the reliability analysis of pipelines. As a first step towards this idea, this paper provides a higher-order-logic formalization of reliability and the series RBD using the HOL theorem prover. For illustration, we present the formal analysis of a simple pipeline that can be modeled as a series RBD of segments with exponentially distributed failure times.

Towards the Formal Reliability Analysis of Oil and Gas Pipelines

In recent times, Wireless Sensor Networks (WSNs) have shown a great potential for monitoring physical or environmental conditions in a variety of safety and financial-critical applications, ranging from medicine to transportation and surveillance. Given the extreme conditions of most of the WSN environments, it is very important to make WSN communication resilient to network failures. Various data transport protocols have been proposed in the literature to serve this purpose. The reliability of these WSN data transport protocols is usually assessed by using Reliability Block Diagrams (RBDs). Traditionally, RBD-based reliability analyses of WSN data transport protocols is done using paper-and-pencil proofs or computer simulations, which cannot ascertain absolute correctness due to their inherent incompleteness. As a complementary approach, we propose to use the higher-order-logic theorem prover HOL to conduct the RBD-based reliability analysis of WSN data transport protocols. In particular, the paper provides a higher-order-logic formalization of series, parallel and parallel-series RBDs. These RBDs are then used to do the formal reliability analysis of the end-to-end (e2e) data transport mechanism, and the Event to Sink Reliable Transport (ESRT) and Reliable Multi-Segment Transport (RMST) data transport protocols.

/pdf/formal-reliability-analysis-of-wireless-sensor-network-data-4i46jr60nz.pdf

Formal reliability analysis of wireless sensor network data transport protocols using HOL

Fault Tree (FT) is a standard failure modeling technique that has been extensively used to predict reliability, availability and safety of many complex engineering systems. In order to facilitate the formal analysis of FT based analyses, a higher-order-logic formalization of FTs has been recently proposed. However, this formalization is quite limited in terms of handling large systems and transformation of FT models into their corresponding Reliability Block Diagram (RBD) structures, i.e., a frequently used transformation in reliability and availability analyses. In order to overcome these limitations, we present a deep embedding based formalization of FTs. In particular, the paper presents a formalization of AND, OR and NOT FT gates, which are in turn used to formalize other commonly used FT gates, i.e., NAND, NOR, XOR, Inhibit, Comparator and majority Voting, and the formal verification of their failure probability expressions. For illustration purposes, we present a formal failure analysis of a communication gateway software for the next generation air traffic management system.

Waqar Ahmed

Papers

Reliability modeling and analysis of communication networks

Formalization of Reliability Block Diagrams in Higher-order Logic

Towards the Formal Reliability Analysis of Oil and Gas Pipelines

Formal reliability analysis of wireless sensor network data transport protocols using HOL

Formalization of Fault Trees in Higher-order Logic: A Deep Embedding Approach