Proceedings of the 12Th International Conference on Characteristics That Make One Method More Efficient Space Operations, Spaceops

Total Page:16

File Type:pdf, Size:1020Kb

Proceedings of the 12Th International Conference on Characteristics That Make One Method More Efficient Space Operations, Spaceops The 26th International Conference ON Automated Planning AND Scheduling June 12-17, 2016. London, UK DoctorAL Consortium Dissertation AbstrACTS The DoctorAL Consortium BRINGS TOGETHER JUNIOR AND EXPERIENCED RESEARCHERS IN planning, SCHEDULING AND RELATED AREAS FROM ACROSS THE globe, IN PARTICULAR THOSE STUDYING FOR A DoctorAL degree. It PROVIDES A FORUM FOR NETWORKING WITH THE ICAPS COMMUNITY IN AN informal, SOCIAL setting. The DoctorAL Consortium WILL BE HELD AS A FULL DAY WORKSHOP ON June 12th, 2016. The PROGRAM INCLUDES AN INVITED TALK ON RESEARCH SKILLS AND CAREER DEVelopment, THE OPPORTUNITY FOR PARTICIPANT TO GIVE A SHORT presentation, AND A POSTER SESSION DURING THE MAIN conference. DC Chairs: • PETER Gregory (UnivERSITY OF Teeside, UK) • LEE McCluskEY (UnivERSITY OF Huddersfield, UK) • Fabio Mercorio (UnivERSITY OF Milan-Bicocca, Italy) AbstrACTS 1 Heuristic Search AND Applications ......................................... 3 Automated Planning AND Scheduling E0 Constellations’ OperATIONS USING Ant ColonY Optimization ... 4 Evridiki Ntagiou SolvER PARAMTER TUNING AND Runtime Predictions OF FleXIBLE Hybrid Mathematical MODELS ......... 10 Michael Barry Constructing Heuristics FOR PDDL+ Planning Domains ............................... 15 Wiktor PiotrOWSKI Risk-SensitivE Planning WITH Dynamic Uncertainty ................................. 21 Liana Marinescu 2 Multi Agent Planning & Plan ExECUTION ...................................... 27 A Distributed Online Multi-Agent Planning System ................................. 28 Rafael CarDOSO IntegrATING Planning AND Recognition TO Close THE InterACTION LOOP ....................... 34 Rick FREEDMAN Distributed Privacy-preserving Multi-agent Planning ................................ 39 AndrEA Bonisoli Planning WITH Concurrent ExECUTION .......................................... 44 Bence Cserna 3 TEMPORAL Planning ................................................... 47 MixED Discrete-Continuous Planning WITH CompleX BehaVIORS .......................... 48 Enrique FERNANDEZ Golzalez Planning WITH FleXIBLE Timelines IN THE Real WORLD ................................. 54 AlessandrO Umbrico POPCorn: Planning WITH ConstrAINED Real Numerics ................................ 60 EmrE SavAS Planning WITH PDDL3.0 Preferences BY Compilation INTO STRIPS WITH Action Costs ............. 66 FRANCESCO PERCASSI Planning Under Uncertainty WITH TEMPORALLY Extended Goals .......................... 71 Alberto Camacho TEMPORAL Inference In FORWARD Search TEMPORAL Planning ............................. 73 ATIF TALUKDAR 4 Planning AND Scheduling ............................................... 79 1 TASK Scheduling AND TRAJECTORY GenerATION OF Multiple Intelligent VEHICLES .................. 80 Jennifer David Decoupled State Space Search .............................................. 83 Daniel Gnad HierARCHICAL TASK Model WITH AlternativES FOR Predictive-reactivE Scheduling ................. 89 MarEK Vlk Numeric Planning ..................................................... 94 Johannes Aldinger Exploiting Search Space Structure IN Classical Planning: Analyses AND Algorithms .............. 97 Matasaru Asai SAT/SMT TECHNIQUES FOR PLANNING PROBLEMS ...................................... 102 Joan Espasa ArxER 5 Planning UNDER Uncertainty AND Applications .................................. 106 Robotic CONTROL THROUGH model-free REINFORCEMENT LEARNING ........................... 107 Ludovic Hofer Exploiting Symmetries IN Sequential Decision Making UNDER Uncertainty ................... 109 Ankit Anand Recommending AND Planning TRIP ItinerARIES FOR Individual TRAVELLERS AND Groups OF TOURISTS ....... 115 KWAN Hui LIM Constructing Plan TREES FOR Simulated PENETRATION TESTING ............................ 121 Dorin ShmaryAHU Optimization Approaches TO Multi-robot Planning AND Scheduling ........................ 128 KYLE Booth 6 Knowledge Engineering AND Applications ..................................... 131 LEARNING Static ConstrAINTS FOR Domain Modeling FROM TRAINING Plans ...................... 132 Rabia Jilani Using GORE METHOD FOR Requirement Engineering OF Planning & Scheduling .................. 137 Javier Martinez Critical ConstrAINED Planning AND AN Application TO Network PENETRATION TESTING .............. 141 MarCEL Steinmetz Human-Robot Communication IN Automated Planning ............................... 145 Aleck MacNally Session 1 Heuristic Search AND Applications 3 Automated Planning and Scheduling ΕΟ Constellations’ Operations with Ant Colony Optimization Evridiki Vasileia Ntagiou Surrey Space Centre, University of Surrey Abstract The Earth observing satellites (EOSs) picture the Earth’s surface, in order to satisfy an assigned goal, In this work we are interested in Automating the which in our case will be the imaging of the Area of process of Planning and Scheduling the operations Interest (AoI). EOSs can acquire images, while of an Earth Observation constellation. To this moving on their usually low altitude orbits. The respect, we represent the problem with a directed acquired data will then need to be transmitted to the graph and use Ant Colony Optimization technique ground station. Until that is possible, the data are to find the optimal solution. In order to verify the stored in the limited on-board memory of the quality of the solution, we employ a dynamical satellites, limiting the images that can be acquired system. We check the scalability of the software before the downlink. system performing simulations. We discuss the next There is a wide interest for automating the P&S process in the EO field, emanating not only steps of this work which involve the coordination of from research organizations and universities [C. multiple spacecraft by means of stigmergy and the Iacopino et al], but also from commercial operators consideration of more than one objectives that need and agencies [S. A. Chien et al.]. The main benefit of to be optimized. autonomy in the planning & scheduling field is in being able to gain maximum value from the Motivation and Scope spacecraft by maximizing the use of on board resources and providing a greater level of The increasing interest in the design and responsiveness to sudden changes of priority, such development of space missions consisting of as when natural disasters strike. Automating the multiple coordinated spacecraft cannot be missed, in P&S process of an Earth Observation mission recent years. Ranging from low cost due to less involves optimization and coordination. It is a system reliability requirements, to giving man the combinatorial optimization problem that takes place ability to perform concurrent scientific observations, in an uncertain dynamic environment. The the advantages of using constellations of spacecraft development of an automated P & S system also have attracted the complete attention of the Space follows the needs of the upcoming missions. These community [T. A. Wagner et al.]. The Earth employ dozens of agile satellites, where a change of Observation market, in specific, is expected to grow attitude translates to a tilt of the imager. We consider at a rate of 16% per year over the next decade [N. agile EOSs that can be steered up to 45° off-nadir in Muscettola et al.]. The current trend is towards the roll axis. constellations consisting of many small satellites, An EO mission may have a single goal e.g. with an increasing number of start-up companies maximize the imaged area, and many constraints, aiming at launching such constellations of 20 e.g. resource or weather constraints. It could also hundreds or more mini-satellites. [G. Richardson et have multiple goals which are conflicting e.g. al.][E. Buchen] maximize the imaged area, while minimizing the The reduction of the satellites’ size and resource used, and again numerous constraints. In corresponding shrinking of their cost has allowed fact, the nature of the problem is such that it includes many end users to benefit from data coming from many constraints, when realistic scenarios are satellites. Since we are dealing with the cooperation studied. In most of the studies, a single-objective of numerous miniaturized satellites of simple optimization problem with numerous constraints is capabilities, which altogether form a very complex considered. This alone, means that our solution will system, the need to automate its management arises. be valid under several assumptions. In order to lift Traditional techniques have failed to cope with such those assumptions we try to decrease the number of a level of complexity. Planning and scheduling constraints and increase the number of goals. In this (P&S) the operations of an EO satellite is the process case, the P&S problem is a multi-objective of determining the time when the satellite performs optimization problem. In order for a mission to be specific arranged tasks, as the available resources, successful, the trade-off among the several images’ collection goals, weather condition and user objectives needs to be studied and a solution requirements evolve. More specifically, the P& S depending on the user requirements needs to be system is responsible for coordinating a produced. constellation’s satellites’ activities in order for the total value of the downlinked data to be maximized. 4 The main challenges that arise when requests, the weather conditions, e.t.c. Hence, the developing a software system that is meant to be challenge is to solve this problem in a way that these autonomous can be grouped in three main continuous environment
Recommended publications
  • Stclang: State Thread Composition As a Foundation for Monadic Dataflow Parallelism Sebastian Ertel∗ Justus Adam Norman A
    STCLang: State Thread Composition as a Foundation for Monadic Dataflow Parallelism Sebastian Ertel∗ Justus Adam Norman A. Rink Dresden Research Lab Chair for Compiler Construction Chair for Compiler Construction Huawei Technologies Technische Universität Dresden Technische Universität Dresden Dresden, Germany Dresden, Germany Dresden, Germany [email protected] [email protected] [email protected] Andrés Goens Jeronimo Castrillon Chair for Compiler Construction Chair for Compiler Construction Technische Universität Dresden Technische Universität Dresden Dresden, Germany Dresden, Germany [email protected] [email protected] Abstract using monad-par and LVars to expose parallelism explicitly Dataflow execution models are used to build highly scalable and reach the same level of performance, showing that our parallel systems. A programming model that targets parallel programming model successfully extracts parallelism that dataflow execution must answer the following question: How is present in an algorithm. Further evaluation shows that can parallelism between two dependent nodes in a dataflow smap is expressive enough to implement parallel reductions graph be exploited? This is difficult when the dataflow lan- and our programming model resolves short-comings of the guage or programming model is implemented by a monad, stream-based programming model for current state-of-the- as is common in the functional community, since express- art big data processing systems. ing dependence between nodes by a monadic bind suggests CCS Concepts • Software and its engineering → Func- sequential execution. Even in monadic constructs that explic- tional languages. itly separate state from computation, problems arise due to the need to reason about opaquely defined state.
    [Show full text]
  • APPLYING MODEL-VIEW-CONTROLLER (MVC) in DESIGN and DEVELOPMENT of INFORMATION SYSTEMS an Example of Smart Assistive Script Breakdown in an E-Business Application
    APPLYING MODEL-VIEW-CONTROLLER (MVC) IN DESIGN AND DEVELOPMENT OF INFORMATION SYSTEMS An Example of Smart Assistive Script Breakdown in an e-Business Application Andreas Holzinger, Karl Heinz Struggl Institute of Information Systems and Computer Media (IICM), TU Graz, Graz, Austria Matjaž Debevc Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia Keywords: Information Systems, Software Design Patterns, Model-view-controller (MVC), Script Breakdown, Film Production. Abstract: Information systems are supporting professionals in all areas of e-Business. In this paper we concentrate on our experiences in the design and development of information systems for the use in film production processes. Professionals working in this area are neither computer experts, nor interested in spending much time for information systems. Consequently, to provide a useful, useable and enjoyable application the system must be extremely suited to the requirements and demands of those professionals. One of the most important tasks at the beginning of a film production is to break down the movie script into its elements and aspects, and create a solid estimate of production costs based on the resulting breakdown data. Several film production software applications provide interfaces to support this task. However, most attempts suffer from numerous usability deficiencies. As a result, many film producers still use script printouts and textmarkers to highlight script elements, and transfer the data manually into their film management software. This paper presents a novel approach for unobtrusive and efficient script breakdown using a new way of breaking down text into its relevant elements. We demonstrate how the implementation of this interface benefits from employing the Model-View-Controller (MVC) as underlying software design paradigm in terms of both software development confidence and user satisfaction.
    [Show full text]
  • Process Scheduling
    PROCESS SCHEDULING ANIRUDH JAYAKUMAR LAST TIME • Build a customized Linux Kernel from source • System call implementation • Interrupts and Interrupt Handlers TODAY’S SESSION • Process Management • Process Scheduling PROCESSES • “ a program in execution” • An active program with related resources (instructions and data) • Short lived ( “pwd” executed from terminal) or long-lived (SSH service running as a background process) • A.K.A tasks – the kernel’s point of view • Fundamental abstraction in Unix THREADS • Objects of activity within the process • One or more threads within a process • Asynchronous execution • Each thread includes a unique PC, process stack, and set of processor registers • Kernel schedules individual threads, not processes • tasks are Linux threads (a.k.a kernel threads) TASK REPRESENTATION • The kernel maintains info about each process in a process descriptor, of type task_struct • See include/linux/sched.h • Each task descriptor contains info such as run-state of process, address space, list of open files, process priority etc • The kernel stores the list of processes in a circular doubly linked list called the task list. TASK LIST • struct list_head tasks; • init the "mother of all processes” – statically allocated • extern struct task_struct init_task; • for_each_process() - iterates over the entire task list • next_task() - returns the next task in the list PROCESS STATE • TASK_RUNNING: running or on a run-queue waiting to run • TASK_INTERRUPTIBLE: sleeping, waiting for some event to happen; awakes prematurely if it receives a signal • TASK_UNINTERRUPTIBLE: identical to TASK_INTERRUPTIBLE except it ignores signals • TASK_ZOMBIE: The task has terminated, but its parent has not yet issued a wait4(). The task's process descriptor must remain in case the parent wants to access it.
    [Show full text]
  • Developing with Pojos: Faster and Easier 3 Chapter 2 ■ J2EE Design Decisions 31
    FROM OUR PEER REVIEW ... “Chris Richardson targets critical design issues for lightweight Java enterprise applications using POJOs with fantastic in-depth exam- ples. This book extends Martin Fowler’s great book, Enterprise Architecture Patterns, as well as the more recent Domain-Driven Design by Eric Evans, by providing practical design guidance and useful examples. It also addresses the architecture and design issues asso- ciated with Spring and Hibernate development, whereas Man- ning’s companion ‘in Action’ books focus primarily on the Spring and Hibernate technologies. “This is a powerful book for architects, senior developers, and consultants. It uniquely combines best practices and design wisdom to integrate domain-driven design and test-driven development for object-oriented Java enterprise applications using lightweight Spring, Hibernate, and JDO technologies. “The table of contents reflects the important topics that most architects and enterprise developers face every day. There is signifi- cant need for a book like this, which shows how to address many common and complex design issues with real-world examples. The content in this book is unique and not really available elsewhere.” DOUG WARREN Software Architect Countrywide Financial “POJOs in Action fills a void: the need for a practical explanation of the techniques used at various levels for the successful building of J2EE projects. This book can be compared with the less enterprise- oriented and more abstract J2EE Development without EJB by Rod Johnson, but Richardson offers a step-by-step guide to a successful J2EE project. The explanations of the various alternatives available for each step provide the main thrust of this book.
    [Show full text]
  • Scheduling: Introduction
    7 Scheduling: Introduction By now low-level mechanisms of running processes (e.g., context switch- ing) should be clear; if they are not, go back a chapter or two, and read the description of how that stuff works again. However, we have yet to un- derstand the high-level policies that an OS scheduler employs. We will now do just that, presenting a series of scheduling policies (sometimes called disciplines) that various smart and hard-working people have de- veloped over the years. The origins of scheduling, in fact, predate computer systems; early approaches were taken from the field of operations management and ap- plied to computers. This reality should be no surprise: assembly lines and many other human endeavors also require scheduling, and many of the same concerns exist therein, including a laser-like desire for efficiency. And thus, our problem: THE CRUX: HOW TO DEVELOP SCHEDULING POLICY How should we develop a basic framework for thinking about scheduling policies? What are the key assumptions? What metrics are important? What basic approaches have been used in the earliest of com- puter systems? 7.1 Workload Assumptions Before getting into the range of possible policies, let us first make a number of simplifying assumptions about the processes running in the system, sometimes collectively called the workload. Determining the workload is a critical part of building policies, and the more you know about workload, the more fine-tuned your policy can be. The workload assumptions we make here are mostly unrealistic, but that is alright (for now), because we will relax them as we go, and even- tually develop what we will refer to as ..
    [Show full text]
  • Scheduling Light-Weight Parallelism in Artcop
    Scheduling Light-Weight Parallelism in ArTCoP J. Berthold1,A.AlZain2,andH.-W.Loidl3 1 Fachbereich Mathematik und Informatik Philipps-Universit¨at Marburg, D-35032 Marburg, Germany [email protected] 2 School of Mathematical and Computer Sciences Heriot-Watt University, Edinburgh EH14 4AS, Scotland [email protected] 3 Institut f¨ur Informatik, Ludwig-Maximilians-Universit¨at M¨unchen, Germany [email protected] Abstract. We present the design and prototype implementation of the scheduling component in ArTCoP (architecture transparent control of parallelism), a novel run-time environment (RTE) for parallel execution of high-level languages. A key feature of ArTCoP is its support for deep process and memory hierarchies, shown in the scheduler by supporting light-weight threads. To realise a system with easily exchangeable components, the system defines a micro-kernel, providing basic infrastructure, such as garbage collection. All complex RTE operations, including the handling of parallelism, are implemented at a separate system level. By choosing Concurrent Haskell as high-level system language, we obtain a prototype in the form of an executable specification that is easier to maintain and more flexible than con- ventional RTEs. We demonstrate the flexibility of this approach by presenting implementations of a scheduler for light-weight threads in ArTCoP, based on GHC Version 6.6. Keywords: Parallel computation, functional programming, scheduling. 1 Introduction In trying to exploit the computational power of parallel architectures ranging from multi-core machines to large-scale computational Grids, we are currently developing a new parallel runtime environment, ArTCoP, for executing parallel Haskell code on such complex, hierarchical architectures.
    [Show full text]
  • Scheduling Weakly Consistent C Concurrency for Reconfigurable
    SUBMISSION TO IEEE TRANS. ON COMPUTERS 1 Scheduling Weakly Consistent C Concurrency for Reconfigurable Hardware Nadesh Ramanathan, John Wickerson, Member, IEEE, and George A. Constantinides Senior Member, IEEE Abstract—Lock-free algorithms, in which threads synchronise These reorderings are invisible in a single-threaded context, not via coarse-grained mutual exclusion but via fine-grained but in a multi-threaded context, they can introduce unexpected atomic operations (‘atomics’), have been shown empirically to behaviours. For instance, if another thread is simultaneously be the fastest class of multi-threaded algorithms in the realm of conventional processors. This article explores how these writing to z, then reordering two instructions above may algorithms can be compiled from C to reconfigurable hardware introduce the behaviour where x is assigned the latest value via high-level synthesis (HLS). but y gets an old one.1 We focus on the scheduling problem, in which software The implication of this is not that existing HLS tools are instructions are assigned to hardware clock cycles. We first wrong; these optimisations can only introduce new behaviours show that typical HLS scheduling constraints are insufficient to implement atomics, because they permit some instruction when the code already exhibits a race condition, and races reorderings that, though sound in a single-threaded context, are deemed a programming error in C [2, §5.1.2.4]. Rather, demonstrably cause erroneous results when synthesising multi- the implication is that if these memory accesses are upgraded threaded programs. We then show that correct behaviour can be to become atomic (and hence allowed to race), then existing restored by imposing additional intra-thread constraints among scheduling constraints are insufficient.
    [Show full text]
  • Fork-Join Pattern
    Fork-Join Pattern Parallel Computing CIS 410/510 Department of Computer and Information Science Lecture 9 – Fork-Join Pattern Outline q What is the fork-join concept? q What is the fork-join pattern? q Programming Model Support for Fork-Join q Recursive Implementation of Map q Choosing Base Cases q Load Balancing q Cache Locality and Cache-Oblivious Algorithms q Implementing Scan with Fork-Join q Applying Fork-Join to Recurrences Introduction to Parallel Computing, University of Oregon, IPCC Lecture 9 – Fork-Join Pattern 2 Fork-Join Philosophy When you come to a fork in the road, take it. (Yogi Bera, 1925 –) Introduction to Parallel Computing, University of Oregon, IPCC Lecture 9 – Fork-Join Pattern 3 Fork-Join Concept q Fork-Join is a fundamental way (primitive) of expressing concurrency within a computation q Fork is called by a (logical) thread (parent) to create a new (logical) thread (child) of concurrency ❍ Parent continues after the Fork operation ❍ Child begins operation separate from the parent ❍ Fork creates concurrency q Join is called by both the parent and child ❍ Child calls Join after it finishes (implicitly on exit) ❍ Parent waits until child joins (continues afterwards) ❍ Join removes concurrency because child exits Introduction to Parallel Computing, University of Oregon, IPCC Lecture 9 – Fork-Join Pattern 4 Fork-Join Concurrency Semantics q Fork-Join is a concurrency control mechanism ❍ Fork increases concurrency ❍ Join decreases concurrency q Fork-Join dependency rules ❍ A parent must join with its forked children
    [Show full text]
  • An Analytical Model for Multi-Tier Internet Services and Its Applications
    An Analytical Model for Multi-tier Internet Services and Its Applications Bhuvan Urgaonkar, Giovanni Pacificiy, Prashant Shenoy, Mike Spreitzery, and Asser Tantawiy Dept. of Computer Science, y Service Management Middleware Dept., University of Massachusetts, IBM T. J. Watson Research Center, Amherst, MA 01003 Hawthorne, NY 10532 fbhuvan,[email protected] fgiovanni,mspreitz,[email protected] ABSTRACT that is responsible for HTTP processing, a middle tier Java enterprise Since many Internet applications employ a multi-tier architecture, server that implements core application functionality, and a back- in this paper, we focus on the problem of analytically modeling the end database that stores product catalogs and user orders. In this behavior of such applications. We present a model based on a net- example, incoming requests undergo HTTP processing, processing work of queues, where the queues represent different tiers of the by Java application server, and trigger queries or transactions at the application. Our model is sufficiently general to capture (i) the database. behavior of tiers with significantly different performance charac- This paper focuses on analytically modeling the behavior of multi- teristics and (ii) application idiosyncrasies such as session-based tier Internet applications. Such a model is important for the follow- workloads, tier replication, load imbalances across replicas, and ing reasons: (i) capacity provisioning, which enables a server farm caching at intermediate tiers. We validate our model using real to determine how much capacity to allocate to an application in or- multi-tier applications running on a Linux server cluster. Our exper- der for it to service its peak workload; (ii) performance prediction, iments indicate that our model faithfully captures the performance which enables the response time of the application to be determined of these applications for a number of workloads and configurations.
    [Show full text]
  • Object Oriented Paradigm/Programming
    an object is an instantiation from a class, e.g., you have a pet cat, who's Object Oriented Paradigm name is Garfield, then Garfield is a object (of the class cat) to invoke an method, simply do obj.method( ) or obj->method( ), the Ming- Hwa Wang, Ph.D. former is object reference syntax, and the latter is pointer syntax Department of Computer Engineering Santa Clara University Relationships a-kind-of relationship: a subclass inherits and adds more attributes Object Oriented Paradigm/Programming (OOP) and/or methods from its super class to become somewhat "specialized" similar to Lego, which kids build new toys from assembling the existing is-a relationship: an object of a subclass is an object of its super class construction blocks of different shapes part-of relationship: OOP - doing programs by reusing (composing/inheriting) objects has-a relationship: (instantiated from classes) as much as possible, and only writing code when no exiting objects can be applied Reusability inheritance Two Fundamental Principles for OOP a sub/child/derived/extended class can inherit all properties from its generalization or reusability: the classes designed should target to super/parent/base/original class, with or without reusability, i.e., it should very generic and can be applied to lots of modification/override or addition situations/applications without much efforts; reusability comes from single inheritance and multiple inheritance (watch out naming inheritance and/or composition conflicts) encapsulation or information hiding: we can hide detailed or composition implementation specific information away from the users/programmers, so changing implementation using the same interfaces will not need Abstract or Virtual Classes modifying the application code only used as a super class for other classes, only specified but not fully defined, and can't be instantiated OOP Language vs.
    [Show full text]
  • Communication and Scheduling Model Design of Distributed Workflow Management System
    Advances in Engineering Research, volume 119 2nd International Conference on Automatic Control and Information Engineering (ICACIE 2017) Communication and Scheduling Model Design of Distributed Workflow Management System Jing Zhao Bin Wei School of Science Key Laboratory of Network & Information Security of APF Xijing University Engineering College of APF Xi’an, China, 710123 Xi’an, China, 710123 [email protected] Abstract—The traditional OA system cannot meet the requirements of modern enterprise. Currently the widely used II. DISTRIBUTED WORKFLOW MANAGEMENT SYSTEM distributed workflow management system (DWFMS) has the The WFMC propose a classic definition of workflow: all problem of load balancing, which makes the enterprise efficiency or part of it supported or automated by a computer. The unimproved. In this paper, on the study of the DWFMS, the workflow management system is to support a batch of model design of common communication transmission and professional set workflow, which is defined by the calculated scheduling are analyzed. Then the real-time scheduling strategy process. It is used to support the definition, management and model is put forward and discussed, which based on feedback control. By using this model in DWFMS, the task can be executive the workflow. It enable the business execution controlled effectively, the load balancing performance of the processes to achieve maximum efficiency. system is improved effectively, and the stability of the system is The distributed workflow system is generally divided into ensured. 3 parts: the distribution of workflow architecture, the distribution of workflow engine and the distribution of Keywords—workflow; communication; scheduling model; workflow model. The workflow engine distribution is the core controller of distributed system.
    [Show full text]
  • Computer Scheduling Methods and Their Countermeasures
    Computer scheduling methods and their countermeasures by EDWARD G. COFFMAN, JR* Princeton University Princeton, New Jersey A anu LEONARD KLEINROCK** University of California Los Angeles, California INTRODUCTION sources. In multi-access, multiprogramming systems The simultaneous demand for computer service by throughput may conveniently be measured in terms of members from a population of users generally results computer operating efficiency defined roughly as the in the formation of queues. These queues are con­ percentage of time the computer spends in perform­ trolled by some computer scheduling method which ing user or customer-directed tasks as compared with chooses the order in which various users receive at­ the time spent in performing executive (overhead type) tention. The goal of this priority scheduling algorithm tasks. We shall avoid trying to measure the program­ is to provide the population of users with a high mers' or users' productivity in a multi-access environ­ grade of service (rapid response, resource availabil­ ment as compared with productivity in the usually less ity, etc.(, at the same time maintaining an acceptable flexible but more efficient batch-processing environ­ throughput rate. The object of the present paper is to ment. For discussions on this subject see References discuss most of the priority scheduling procedures 1 and 2 and the bibliography of Reference 3. that have been considered in the past few years, to dis­ With a somewhat different orientation some of these cuss in a coherent way their effectiveness and weak­ topics have been covered elsewhere. In particular, Coffman,4 Greenberger5 and in more detail Estrin nesses in terms of the performance measures men­ 6 tioned above, to describe what the analysis of related and Kleinrock have reviewed the many applications queueing models has been able to provide in the way of queueing theory to the analysis of multiprogram­ of design aids, and in this last respect, to point out ming systems.
    [Show full text]