Execution Of Distributed Programs Research Articles

Grace: Low-cost time-synchronized GPIO tracing for IoT testbeds

Testbeds have become a vital tool for evaluating and benchmarking applications and algorithms in the Internet of Things (IoT). IoT testbeds commonly consist of low-power IoT devices augmented with observer nodes providing control, debugging, logging, and often also power-profiling capabilities. Today, the research community operates numerous testbeds, sometimes with hundreds of IoT nodes, to allow for detailed and large-scale evaluation. Most testbeds, however, lack opportunities for tracing distributed program execution with high accuracy in time, for example, via minimally invasive, distributed GPIO tracing. And the ones that do, like Flocklab, are built from custom hardware, which is often too complex, inflexible, or expensive to use for other research groups.This paper closes this gap and introduces Grace, a low-cost, retrofittable, distributed, and time-synchronized GPIO tracing system built from off-the-shelf components, costing less than €20 per node. Grace extends observer nodes in a testbed with (1) time-synchronization via wireless sub-GHz transceivers and (2) logic analyzers for GPIO tracing and logging, enabling time-synchronized GPIO tracing at a frequency of up to 8 MHz. We deploy Grace in a testbed and evaluate it, showing that it achieves an average time synchronization error between nodes of 1.53 μs using a single time source, and 15.3 μs between nodes using different time sources, sufficient for most IoT applications.

ИСПОЛЬЗОВАНИЕ СИСТЕМНОГО АНАЛИЗА ДЛЯ ОПТИМИЗАЦИИ ОБРАБОТКИ БОЛЬШИХ ДАННЫХ

Modern information technologies have made changes in the way data is collected, stored and processed. As a result, there is an urgent problem of developing and applying new methods of approaches to data analysis. For the convenience of working with big data, a large number of frameworks and distributed data warehouses have been implemented. One of the well-known methods to support the execution of largescale distributed application programs is MapReduce. The article presents an overview of modern technologies used in the field of big data processing, market analysis, as well as a comparison of modern analytical database management systems.

The ArmarX Statechart Concept: Graphical Programing of Robot Behavior

Programming sophisticated robots such as service robots or humanoids is still a complex endeavor. Although programming robotic applications requires specialist knowledge, a robot software environment should support convenient development while maintaining full flexibility needed when realizing challenging robotics tasks. In addition, several desirable properties should be fulfilled, such as robustness, reusability of existing programs, and skill transfer between robots. In this work, we introduce the ArmarX statechart concept, which is used for describing control and data flow of robot programs. This event-driven statechart approach of ArmarX helps realizing important features such as increased robustness through distributed program execution, convenient programming through graphical user interfaces, and versatility by interweaving dynamic statechart structure with custom user-code. We show that using hierarchical and distributed statecharts increases reusability, allows skill transfer between robots, and hides complexity in robot programming by splitting robot behavior into control flow and functionality.

PEGASUS DA framework for distributed program execution control based on application global states monitoring

SummaryThe paper presents basic design decisions taken in the implementation of a novel distributed program design framework Program Execution Governed by Asynchronous SUpervision of States in Distributed Applications (PEGASUS DA). This framework supports application program execution control design based on evolved automated program global states monitoring. The framework provides to a programmer a ready‐to‐use infrastructure for defining and handling local and global application states to be used as the basis for program execution control decisions. The paper presents how the provided infrastructure can be used for automated construction of strongly consistent application global states. Also, the use of global states for graphically supported specification of distributed program execution control is covered for clusters of multicore processors based on multithreading and message passing. Both architecture and implementation solutions applied for PEGASUS DA are discussed. Especially, multivariant algorithms for construction of program strongly consistent global states and methods for their use in the design of distributed program global execution control are shown. The use of PEGASUS DA is illustrated with an example of a traveling salesman problem solved by the branch and bound method. Copyright © 2015 John Wiley & Sons, Ltd.

A Distributed Program Global Execution Control Environment Applied to Load balancing

The paper is concerned with a new distributed program design environment based on the global application states monitoring. The environment called PEGASUS (from Program Execution Governed by Asynchronous SUpervision of States) supplies to a programmer a ready to use control primitives to design distributed program execution control in which decisions for synchronous and asynchronous control actions are based on predicates evaluated on global application states. Such strongly consistent global application states are automatically constructed by the run-time system which additionally provides mechanisms for their analysis and organizing the respective program execution control in processes and threads of user programs executed in multicore processors. The PEGASUS control mechanisms are graphically supported in the respective program design framework. The paper first presents main general features of the PEGASUS environment. Next, it presents a method for load balancing inside distributed programs based on a set of parameters which are dynamically measured during program execution. Then, the paper presents how the described load balancing method can be implemented inside the PEGASUS environment taking as an example distributed programs for solving the Traveling Salesman Problem (TSP).

Dynamic Distributed Programs Control Based on Global Program States Monitoring

The paper concerns designing distributed program execution control based on global application states monitoring in the presence of a dynamic number of processes and threads. Global program execution control is based on application states monitoring at the level of processes/threads in clusters of multi--core processors. A special control infrastructure is proposed based on synchronizers, which collect state information from processes and threads, detect strongly consistent application global states, evaluate control predicates and send respective control signals. An algorithm for detection of strongly consistent global states for a variable number of processes/threads is presented.

MACLP: multi agent constraint logic programming

Abstract Multi Agent Systems (MAS) have become the key technology for decomposing complex problems in order to solve them more efficiently, or for problems distributed in nature. However, many industrial applications besides their distributed nature, also involve a large number of parameters and constraints among them, i.e. they are combinatorial. Solving such particularly hard problems efficiently requires programming tools that combine MAS technology with a programming schema that facilitates the modeling and solution of constraints. This paper presents MACLP (Multi Agent Constraint Logic Programming), a logic-programming platform for building, in a declarative way, multi agent systems with constraint-solving capabilities. MACLP extends CSPCONS, a logic programming system that permits distributed program execution through communicating sequential Prolog processes with constraints, by providing all the necessary facilities for communication between agents. These facilities abstract from the programmer all the low-level details of the communication and allow him to focus on the development of the agent itself.

Error detection and diagnosis for fault tolerance in distributed systems

The early error detection and the understanding of the nature and conditions of an error occurrence can be useful to make an effective and efficient recovery in distributed systems. Various distributed system extensions were introduced for the implementation of fault tolerance in distributed software systems. These extensions rely mainly on the exchange of contextual information appended to every transmitted application specific message. Ideally, this information should be used for checkpointing, error detection, diagnosis and recovery should a transient failure occur later during the distributed program execution. In this paper, we present a generalized extension suitable for fault-tolerant distributed systems such as communication software systems and its detection capabilities are shown. Our extension is based on the execution of message validity test prior to the transmission of messages and the piggybacking of contextual information to facilitate the detection and diagnosis of transient faults in the distributed system.

Modelling and Analysis of Distributed Program Execution in BETA Using Coloured Petri Nets

<p>Recently, abstractions supporting distributed program execution in the object-oriented language BETA have been designed. A BETA object on one computer may invoke a remote object, i.e., an object hosted by another computer. In this project, the formalism of Coloured Petri Nets (CP-nets or CPN) is used to describe and analyse the protocol for remote object invocation. In the first place, we build a model in order to describe, understand, and improve the protocol. Remote object invocation in BETA is modelled on the level of threads (lightweight processes) with emphasis on the competition for access to critical regions and shared resources. Secondly, the model is analysed. It is formally proved that it has a set of desirable properties, e.g., absence of dead markings.</p><p><strong>Topics:</strong> Systemdesign and verfication using nets; higher-level nets models; computer tools for nets; experience with using nets, case studies; application of nets to protocols.</p>