Design and analysis of an efficient energy algorithm in wireless social sensor networks

Because mobile ad hoc networks have characteristics such as lack of center nodes, multi-hop routing and changeable topology, the existing checkpoint technologies for normal mobile networks cannot be applied well to mobile ad hoc networks. Considering the multi-frequency hierarchy structure of ad hoc networks, this paper proposes a hybrid checkpointing strategy which combines the techniques of synchronous checkpointing with asynchronous checkpointing, namely the checkpoints of mobile terminals in the same cluster remain synchronous, and the checkpoints in different clusters remain asynchronous. This strategy could not only avoid cascading rollback among the processes in the same cluster, but also avoid too many message transmissions among the processes in different clusters. What is more, it can reduce the communication delay. In order to assure the consistency of the global states, this paper discusses the correctness criteria of hybrid checkpointing, which includes the criteria of checkpoint taking, rollback recovery and indelibility. Based on the designed Intra-Cluster Checkpoint Dependence Graph and Inter-Cluster Checkpoint Dependence Graph, the elimination rules for different kinds of checkpoints are discussed, and the algorithms for the same cluster checkpoints, different cluster checkpoints, and rollback recovery are also given. Experimental results demonstrate the proposed hybrid checkpointing strategy is a preferable trade-off method, which not only synthetically takes all kinds of resource constraints of Ad hoc networks into account, but also outperforms the existing schemes in terms of the dependence to cluster heads, the recovery time compared to the pure synchronous, and the pure asynchronous checkpoint advantage. © 2017 by the authors. Licensee MDPI, Basel, Switzerland

Study and Design of Global Snapshot Compilation Protocols for Rollback-Recovery in Mobile Distributed System

Checkpoint is characterized as an assigned place in a program at which ordinary process is intruded on particularly to protect the status data important to permit resumption of handling at a later time. A conveyed framework is an accumulation of free elements that participate to tackle an issue that can't be separately comprehended. A versatile figuring framework is a dispersed framework where some of procedures are running on portable hosts (MHs). The presence of versatile hubs in an appropriated framework presents new issues that need legitimate dealing with while outlining a checkpointing calculation for such frameworks. These issues are portability, detachments, limited power source, helpless against physical harm, absence of stable stockpiling and so forth. As of late, more consideration has been paid to giving checkpointing conventions to portable frameworks. Least process composed checkpointing is an alluring way to deal with present adaptation to internal failure in portable appropriated frameworks straightforwardly. This approach is without domino, requires at most two recovery_points of a procedure on stable stockpiling, and powers just a base number of procedures to recovery_point. In any case, it requires additional synchronization messages, hindering of the basic calculation or taking some futile recovery_points. In this paper, we complete the writing review of some Minimum-process Coordinated Checkpointing Algorithms for Mobile Computing System

An Efficient Synchronous Checkpointing Protocol for Mobile Distributed Systems

Recent years have witnessed rapid development of mobile communications and become part of everyday life for most people. In order to transparently adding fault tolerance in mobile distributed systems, Minimum-process coordinated checkpointing is preferable but it may require blocking of processes, extra synchronization messages or taking some useless checkpoints. All-process checkpointing may lead to exceedingly high checkpointing overhead. In order to balance the checkpointing overhead and the loss of computation on recovery, we propose a hybrid checkpointing algorithm, wherein an all-process coordinated checkpoint is taken after the execution of minimum-process coordinated checkpointing algorithm for a fixed number of times. In the minimum-process coordinated checkpointing algorithm; an effort has been made to optimize the number of useless checkpoints and blocking of processes using probabilistic approach and by computing an interacting set of processes at beginning. We try to reduce the loss of checkpointing effort when any process fails to take its checkpoint in coordination with others. We reduce the size of checkpoint sequence number piggybacked on each computation messag

Portable Checkpointing for Parallel Applications

High Performance Computing (HPC) systems represent the peak of modern computational capability. As ever-increasing demands for computational power have fuelled the demand for ever-larger computing systems, modern HPC systems have grown to incorporate hundreds, thousands or as many as 130,000 processors. At these scales, the huge number of individual components in a single system makes the probability that a single component will fail quite high, with today's large HPC systems featuring mean times between failures on the order of hours or a few days. As many modern computational tasks require days or months to complete, fault tolerance becomes critical to HPC system design. The past three decades have seen significant amounts of research on parallel system fault tolerance. However, as most of it has been either theoretical or has focused on low-level solutions that are embedded into a particular operating system or type of hardware, this work has had little impact on real HPC systems. This thesis attempts to address this lack of impact by describing a high-level approach for implementing checkpoint/restart functionality that decouples the fault tolerance solution from the details of the operating system, system libraries and the hardware and instead connects it to the APIs implemented by the above components. The resulting solution enables applications that use these APIs to become self-checkpointing and self-restarting regardless of the the software/hardware platform that may implement the APIs. The particular focus of this thesis is on the problem of checkpoint/restart of parallel applications. It presents two theoretical checkpointing protocols, one for the message passing communication model and one for the shared memory model. The former is the first protocol to be compatible with application-level checkpointing of individual processes, while the latter is the first protocol that is compatible with arbitrary shared memory models, APIs, implementations and consistency protocols. These checkpointing protocols are used to implement checkpointing systems for applications that use the MPI and OpenMP parallel APIs, respectively, and are first in providing checkpoint/restart to arbitrary implementations of these popular APIs. Both checkpointing systems are extensively evaluated on multiple software/hardware platforms and are shown to feature low overheads

Transiently Powered Computers

Demand for compact, easily deployable, energy-efficient computers has driven the development of general-purpose transiently powered computers (TPCs) that lack both batteries and wired power, operating exclusively on energy harvested from their surroundings. TPCs\u27 dependence solely on transient, harvested power offers several important design-time benefits. For example, omitting batteries saves board space and weight while obviating the need to make devices physically accessible for maintenance. However, transient power may provide an unpredictable supply of energy that makes operation difficult. A predictable energy supply is a key abstraction underlying most electronic designs. TPCs discard this abstraction in favor of opportunistic computation that takes advantage of available resources. A crucial question is how should a software-controlled computing device operate if it depends completely on external entities for power and other resources? The question poses challenges for computation, communication, storage, and other aspects of TPC design. The main idea of this work is that software techniques can make energy harvesting a practicable form of power supply for electronic devices. Its overarching goal is to facilitate the design and operation of usable TPCs. This thesis poses a set of challenges that are fundamental to TPCs, then pairs these challenges with approaches that use software techniques to address them. To address the challenge of computing steadily on harvested power, it describes Mementos, an energy-aware state-checkpointing system for TPCs. To address the dependence of opportunistic RF-harvesting TPCs on potentially untrustworthy RFID readers, it describes CCCP, a protocol and system for safely outsourcing data storage to RFID readers that may attempt to tamper with data. Additionally, it describes a simulator that facilitates experimentation with the TPC model, and a prototype computational RFID that implements the TPC model. To show that TPCs can improve existing electronic devices, this thesis describes applications of TPCs to implantable medical devices (IMDs), a challenging design space in which some battery-constrained devices completely lack protection against radio-based attacks. TPCs can provide security and privacy benefits to IMDs by, for instance, cryptographically authenticating other devices that want to communicate with the IMD before allowing the IMD to use any of its battery power. This thesis describes a simplified IMD that lacks its own radio, saving precious battery energy and therefore size. The simplified IMD instead depends on an RFID-scale TPC for all of its communication functions. TPCs are a natural area of exploration for future electronic design, given the parallel trends of energy harvesting and miniaturization. This work aims to establish and evaluate basic principles by which TPCs can operate

Priority-based speculative locking protocols for distributed real-time database systems.

With globalization, multinational networked organizations' need for exchange of information has led to the emergence of applications that are heavily dependent on globally distributed and constantly changing data. Such applications include, stock trading, Computer Aided Design and Manufacturing (CAD/CAM), online reservation systems, telecommunication systems, e-commerce systems and real time navigation systems. These applications introduce the need for distributed real time database systems (DRTDBS) which must access/manipulate data spread over a network in addition to meeting the real time constraints and maintaining database consistency. In order to improve performance within DRTDBS, attention needs to be given to concurrency control mechanism and transaction's time constraints. A number of protocols have been suggested in recent years to address these issues. One of the proposed protocols, Speculative Locking (SL), has especially demonstrated the capability of improving performance within Distributed Database System by allowing parallelism between conflicting transactions without violating serializability. This research extends SL by giving it the capability of taking a transaction's priority into consideration when scheduling transactions. In addition, a nested transaction model is used to access the data that is distributed across the network. We propose two new Priority-based Speculative Locking protocols: (1) Preemptive Speculative Locking (PSL) and (2) Priority inheritance Speculative Locking (PiSL). PSL extends SL by allowing any incoming higher priority transaction to preempt and abort any lower priority transaction in case of lock conflict thus giving the higher priority transaction a chance to meet the deadline. PiSL, on the other hand, attempts to prevent any wasted work by avoiding preemption by a higher priority transaction. Instead, the lower priority transaction inherits the priority of the blocked transaction. This gives both transactions an opportunity to meet their deadline whenever possible.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b159863