McMahon, Troy
2015-05-01
© 2015 IEEE. Reachable volumes are a new technique that allows one to efficiently restrict sampling to feasible/reachable regions of the planning space even for high degree of freedom and highly constrained problems. However, they have so far only been applied to graph-based sampling-based planners. In this paper we develop the methodology to apply reachable volumes to tree-based planners such as Rapidly-Exploring Random Trees (RRTs). In particular, we propose a reachable volume RRT called RVRRT that can solve high degree of freedom problems and problems with constraints. To do so, we develop a reachable volume stepping function, a reachable volume expand function, and a distance metric based on these operations. We also present a reachable volume local planner to ensure that local paths satisfy constraints for methods such as PRMs. We show experimentally that RVRRTs can solve constrained problems with as many as 64 degrees of freedom and unconstrained problems with as many as 134 degrees of freedom. RVRRTs can solve problems more efficiently than existing methods, requiring fewer nodes and collision detection calls. We also show that it is capable of solving difficult problems that existing methods cannot.
A practical approach to model checking Duration Calculus using Presburger Arithmetic
DEFF Research Database (Denmark)
Hansen, Michael Reichhardt; Dung, Phan Anh; Brekling, Aske Wiid
2014-01-01
This paper investigates the feasibility of reducing a model-checking problem K ⊧ ϕ for discrete time Duration Calculus to the decision problem for Presburger Arithmetic. Theoretical results point at severe limitations of this approach: (1) the reduction in Fränzle and Hansen (Int J Softw Inform 3...
Directory of Open Access Journals (Sweden)
Arnaud Gotlieb
2013-02-01
Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.
From functional programming to multicore parallelism: A case study based on Presburger Arithmetic
DEFF Research Database (Denmark)
Dung, Phan Anh; Hansen, Michael Reichhardt
2011-01-01
The overall goal of this work is studying parallelization of functional programs with the specific case study of decision procedures for Presburger Arithmetic (PA). PA is a first order theory of integers accepting addition as its only operation. Whereas it has wide applications in different areas......, we are interested in using PA in connection with the Duration Calculus Model Checker (DCMC) [5]. There are effective decision procedures for PA including Cooper’s algorithm and the Omega Test; however, their complexity is extremely high with doubly exponential lower bound and triply exponential upper...... in the SMT-solver Z3 [8] which has the capability of solving Presburger formulas. Functional programming is well-suited for the domain of decision procedures, and its immutability feature helps to reduce parallelization effort. While Haskell has progressed with a lot of parallelismrelated research [6], we...
Bidirectional reachability-based modules
CSIR Research Space (South Africa)
Nortje, R
2011-07-01
Full Text Available The authors introduce an algorithm for MinA extraction in EL based on bidirectional reachability. They obtain a significant reduction in the size of modules extracted at almost no additional cost to that of extracting standard reachability...
Planning with Reachable Distances
Tang, Xinyu
2009-01-01
Motion planning for spatially constrained robots is difficult due to additional constraints placed on the robot, such as closure constraints for closed chains or requirements on end effector placement for articulated linkages. It is usually computationally too expensive to apply sampling-based planners to these problems since it is difficult to generate valid configurations. We overcome this challenge by redefining the robot\\'s degrees of freedom and constraints into a new set of parameters, called reachable distance space (RD-space), in which all configurations lie in the set of constraint-satisfying subspaces. This enables us to directly sample the constrained subspaces with complexity linear in the robot\\'s number of degrees of freedom. In addition to supporting efficient sampling, we show that the RD-space formulation naturally supports planning, and in particular, we design a local planner suitable for use by sampling-based planners. We demonstrate the effectiveness and efficiency of our approach for several systems including closed chain planning with multiple loops, restricted end effector sampling, and on-line planning for drawing/sculpting. We can sample single-loop closed chain systems with 1000 links in time comparable to open chain sampling, and we can generate samples for 1000-link multi-loop systems of varying topology in less than a second. © 2009 Springer-Verlag.
Graphical Multiprocessing Analysis Tool (GMAT)
Energy Technology Data Exchange (ETDEWEB)
Seager, M.K.; Campbell, S.; Sikora, S.; Strout, R.; Zosel, M.
1988-03-01
The design and debugging of parallel programs is a difficult task due to the complex synchronization and data scoping issues involed. to aid the programmer in paralle code dvelopment we have developed two methodologies for the graphical display of execution of parallel codes. The Graphical Multiprocessing Analysis Tools (GMAT) consist of stategraph, which represents an inheritance tree of task states, and timeline, which represens task as flowing sequence of events. Information about the code can be displayed as the application runs (dynamic mode) or played back with time under user control (static mode). This document discusses the design and user interface issues involved in developing the parallel application display GMAT family. Also, we present an introductory user's guide for both tools. 4 figs.
Reachability Analysis of Probabilistic Systems
DEFF Research Database (Denmark)
D'Argenio, P. R.; Jeanett, B.; Jensen, Henrik Ejersbo
2001-01-01
than the original model, and may safely refute or accept the required property. Otherwise, the abstraction is refined and the process repeated. As the numerical analysis involved in settling the validity of the property is more costly than the refinement process, the method profits from applying......We report on new strategies for model checking quantitative reachability properties of Markov decision processes by successive refinements. In our approach, properties are analyzed on abstractions rather than directly on the given model. Such abstractions are expected to be significantly smaller...
Stochastic Reachability Analysis of Hybrid Systems
Bujorianu, Luminita Manuela
2012-01-01
Stochastic reachability analysis (SRA) is a method of analyzing the behavior of control systems which mix discrete and continuous dynamics. For probabilistic discrete systems it has been shown to be a practical verification method but for stochastic hybrid systems it can be rather more. As a verification technique SRA can assess the safety and performance of, for example, autonomous systems, robot and aircraft path planning and multi-agent coordination but it can also be used for the adaptive control of such systems. Stochastic Reachability Analysis of Hybrid Systems is a self-contained and accessible introduction to this novel topic in the analysis and development of stochastic hybrid systems. Beginning with the relevant aspects of Markov models and introducing stochastic hybrid systems, the book then moves on to coverage of reachability analysis for stochastic hybrid systems. Following this build up, the core of the text first formally defines the concept of reachability in the stochastic framework and then...
Reachability modules for the description logic SRIQ
CSIR Research Space (South Africa)
Nortje, R
2013-12-01
Full Text Available In this paper we investigate module extraction for the Description Logic SRIQ. We formulate modules in terms of the reachability problem for directed hypergraphs. Using inseperability relations, we investigate the module-theoretic properties...
Stochastic observability, reconstructibility, controllability, and reachability
Liu, Andrew R.
2011-01-01
This thesis formulates versions of observability, reconstructibility, controllability, and reachability for stochastic linear and nonlinear systems. The concepts of observability and reconstructibility concern whether the measurements of a system suffice to construct a complete characterization of the system behavior while the concepts of controllability and reachability concern whether the actuation of the system suffices to cause the system to behave according to various user specifications...
Reachability problems for communicating finite state machines
Pachl, Jan
2012-01-01
The paper deals with the verification of reachability properties in a commonly used state transition model of communication protocols, which consists of finite state machines connected by potentially unbounded FIFO channels. Although simple reachability problems are undecidable for general protocols with unbounded channels, they are decidable for the protocols with the recognizable channel property. The decidability question is open for the protocols with the rational channel property.
Distributed Algorithms for Time Optimal Reachability Analysis
DEFF Research Database (Denmark)
Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand
2016-01-01
Time optimal reachability analysis is a novel model based technique for solving scheduling and planning problems. After modeling them as reachability problems using timed automata, a real-time model checker can compute the fastest trace to the goal states which constitutes a time optimal schedule....... We propose distributed computing to accelerate time optimal reachability analysis. We develop five distributed state exploration algorithms, implement them in \\uppaal enabling it to exploit the compute resources of a dedicated model-checking cluster. We experimentally evaluate the implemented...... algorithms with four models in terms of their ability to compute near- or proven-optimal solutions, their scalability, time and memory consumption and communication overhead. Our results show that distributed algorithms work much faster than sequential algorithms and have good speedup in general....
Robust Reachability of Boolean Control Networks.
Li, Fangfei; Tang, Yang
2016-04-20
Boolean networks serve a powerful tool in analysis of genetic regulatory networks since it emphasizes the fundamental principles and establishes a nature framework for capturing the dynamics of regulation of cellular states. In this paper, the robust reachability of Boolean control networks is investigated by means of semi-tensor product. Necessary and sufficient conditions for the robust reachability of Boolean control networks are provided, in which control inputs relying on disturbances or not are considered, respectively. Besides, the corresponding control algorithms are developed for these two cases. A reduced model of the lac operon in the Escherichia coli is presented to show the effectiveness of the presented results.
An Algorithm to Construct Concurrent Reachability Graph of Petri Nets
Institute of Scientific and Technical Information of China (English)
张金泉; 倪丽娜; 蒋昌俊
2004-01-01
Reachability graph is a very important tool to analyze the dynamic properties of Petri nets, but the concurrent relation of transitions in Petri nets cannot be represented by reachability graph. Petri net is a concurrent system, while reachability graph is a serial one. However, concurrency is a kind of property which is not only very significant but also difficult to be analyzed and controlled. This paper presents the concepts of concurrent reachable marking and concurrent reachable graph in order to represent and analyze the concurrent system. The algorithm constructing concurrent reachable marking set and concurrent reachability graph is also shown so that we can study the response problems among services in a network computing environment and analyze the throughput of the system. The Dining Philosophers Problem, which is a classic problem of describing the management of concurrent resources, is given as an example to illustrate the significance of concurrent reachability graph.
Reachability via Compositionality in Petri nets
Sobocinski, Paweł; Stephens, Owen
2013-01-01
We introduce a novel technique for checking reachability in Petri nets that relies on a recently introduced compositional algebra of nets. We prove that the technique is correct, and discuss our implementation. We report promising experimental results on some well-known examples.
Reachability Analysis of Sampling Based Planners
Geraerts, R.J.; Overmars, M.H.
2005-01-01
The last decade, sampling based planners like the Probabilistic Roadmap Method have proved to be successful in solving complex motion planning problems. We give a reachability based analysis for these planners which leads to a better understanding of the success of the approach and enhancements of t
Reachability analysis of switched linear discrete singular systems
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
This paper studies the reachability problem of the switched linear discrete singular (SLDS) systems. Under the condition that all subsystems are regular, the reachability of the SLDS systems is characterized based on a peculiar repeatedly introduced switching sequence. The necessary and sufficient conditions are obtained for the reachability of the SLDS systems.
Improvement of multiprocessing performance by using optical centralized shared bus
Han, Xuliang; Chen, Ray T.
2004-06-01
With the ever-increasing need to solve larger and more complex problems, multiprocessing is attracting more and more research efforts. One of the challenges facing the multiprocessor designers is to fulfill in an effective manner the communications among the processes running in parallel on multiple multiprocessors. The conventional electrical backplane bus provides narrow bandwidth as restricted by the physical limitations of electrical interconnects. In the electrical domain, in order to operate at high frequency, the backplane topology has been changed from the simple shared bus to the complicated switched medium. However, the switched medium is an indirect network. It cannot support multicast/broadcast as effectively as the shared bus. Besides the additional latency of going through the intermediate switching nodes, signal routing introduces substantial delay and considerable system complexity. Alternatively, optics has been well known for its interconnect capability. Therefore, it has become imperative to investigate how to improve multiprocessing performance by utilizing optical interconnects. From the implementation standpoint, the existing optical technologies still cannot fulfill the intelligent functions that a switch fabric should provide as effectively as their electronic counterparts. Thus, an innovative optical technology that can provide sufficient bandwidth capacity, while at the same time, retaining the essential merits of the shared bus topology, is highly desirable for the multiprocessing performance improvement. In this paper, the optical centralized shared bus is proposed for use in the multiprocessing systems. This novel optical interconnect architecture not only utilizes the beneficial characteristics of optics, but also retains the desirable properties of the shared bus topology. Meanwhile, from the architecture standpoint, it fits well in the centralized shared-memory multiprocessing scheme. Therefore, a smooth migration with substantial
Does target viewing time influence perceived reachability?
Gabbard, Carl; Ammar, Diala
2007-09-01
This study examined the influence of target viewing time on perceived (estimates of) reachability. Right-handed participants were asked to judge the simulated reachability of midline targets using their dominant limb in viewing conditions of 150 ms, 500 ms, 1 s and 2 s. Responses were compared to actual maximum reach. In reference to percent error, interestingly, the 150 ms condition revealed the least error at peripersonal targets and the most inaccuracy with distal (extrapersonal) targets. This condition was also distinct with a significant overestimation bias -- a common observation in earlier studies. However, with increasing viewing time this bias was reduced. These data provide evidence that 150 ms is effective for estimating reach within one's general peripersonal workspace. However, with judgments distal from that point, more time enhanced accuracy, with 500 ms and 1 s being optimal. Overall results are discussed relative to perceptual effectiveness in programming reaching movements.
A market model: uncertainty and reachable sets
Directory of Open Access Journals (Sweden)
Raczynski Stanislaw
2015-01-01
Full Text Available Uncertain parameters are always present in models that include human factor. In marketing the uncertain consumer behavior makes it difficult to predict the future events and elaborate good marketing strategies. Sometimes uncertainty is being modeled using stochastic variables. Our approach is quite different. The dynamic market with uncertain parameters is treated using differential inclusions, which permits to determine the corresponding reachable sets. This is not a statistical analysis. We are looking for solutions to the differential inclusions. The purpose of the research is to find the way to obtain and visualise the reachable sets, in order to know the limits for the important marketing variables. The modeling method consists in defining the differential inclusion and find its solution, using the differential inclusion solver developed by the author. As the result we obtain images of the reachable sets where the main control parameter is the share of investment, being a part of the revenue. As an additional result we also can define the optimal investment strategy. The conclusion is that the differential inclusion solver can be a useful tool in market model analysis.
Reachability for Finite-State Process Algebras Using Static Analysis
DEFF Research Database (Denmark)
Skrypnyuk, Nataliya; Nielson, Flemming
2011-01-01
In this work we present an algorithm for solving the reachability problem in finite systems that are modelled with process algebras. Our method uses Static Analysis, in particular, Data Flow Analysis, of the syntax of a process algebraic system with multi-way synchronisation. The results...... of the Data Flow Analysis are used in order to “cut off” some of the branches in the reachability analysis that are not important for determining, whether or not a state is reachable. In this way, it is possible for our reachability algorithm to avoid building large parts of the system altogether and still...
Sampling-based motion planning with reachable volumes: Theoretical foundations
McMahon, Troy
2014-05-01
© 2014 IEEE. We introduce a new concept, reachable volumes, that denotes the set of points that the end effector of a chain or linkage can reach. We show that the reachable volume of a chain is equivalent to the Minkowski sum of the reachable volumes of its links, and give an efficient method for computing reachable volumes. We present a method for generating configurations using reachable volumes that is applicable to various types of robots including open and closed chain robots, tree-like robots, and complex robots including both loops and branches. We also describe how to apply constraints (both on end effectors and internal joints) using reachable volumes. Unlike previous methods, reachable volumes work for spherical and prismatic joints as well as planar joints. Visualizations of reachable volumes can allow an operator to see what positions the robot can reach and can guide robot design. We present visualizations of reachable volumes for representative robots including closed chains and graspers as well as for examples with joint and end effector constraints.
Sparse Dataflow Analysis with Pointers and Reachability
DEFF Research Database (Denmark)
Madsen, Magnus; Møller, Anders
2014-01-01
for a sparse analysis framework that supports pointers and reachability. We present such a framework, which uses static single assignment form for heap addresses and computes def-use information on-the-fly. We also show that essential information about dominating definitions can be maintained efficiently using...... quadtrees. The framework is presented as a systematic modification of a traditional dataflow analysis algorithm. Our experimental results demonstrate the effectiveness of the technique for a suite of JavaScript programs. By also comparing the performance with an idealized staged approach that computes...
Distributed Algorithms for Time Optimal Reachability Analysis
DEFF Research Database (Denmark)
Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand
2016-01-01
. We propose distributed computing to accelerate time optimal reachability analysis. We develop five distributed state exploration algorithms, implement them in \\uppaal enabling it to exploit the compute resources of a dedicated model-checking cluster. We experimentally evaluate the implemented...... algorithms with four models in terms of their ability to compute near- or proven-optimal solutions, their scalability, time and memory consumption and communication overhead. Our results show that distributed algorithms work much faster than sequential algorithms and have good speedup in general....
Reachability cuts for the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Lysgaard, Jens
2004-01-01
This paper introduces a class of cuts, called reachability cuts, for the Vehicle Routing Problem with Time Windows (VRPTW). Reachability cuts are closely related to cuts derived from precedence constraints in the Asymmetric Traveling Salesman Problem with Time Windows and to k-path cuts...
Reachability cuts for the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Lysgaard, Jens
2004-01-01
This paper introduces a class of cuts, called reachability cuts, for the Vehicle Routing Problem with Time Windows (VRPTW). Reachability cuts are closely related to cuts derived from precedence constraints in the Asymmetric Traveling Salesman Problem with Time Windows and to k-path cuts...
Multicore in Production: Advantages and Limits of the Multiprocess Approach
Binet, S; The ATLAS collaboration; Lavrijsen, W; Leggett, Ch; Lesny, D; Jha, M K; Severini, H; Smith, D; Snyder, S; Tatarkhanov, M; Tsulaia, V; van Gemmeren, P; Washbrook, A
2011-01-01
The shared memory architecture of multicore CPUs provides HENP developers with the opportunity to reduce the memory footprint of their applications by sharing memory pages between the cores in a processor. ATLAS pioneered the multi-process approach to parallelizing HENP applications. Using Linux fork() and the Copy On Write mechanism we implemented a simple event task farm which allows to share up to 50% memory pages among event worker processes with negligible CPU overhead. By leaving the task of managing shared memory pages to the operating system, we have been able to run in parallel large reconstruction and simulation applications originally written to be run in a single thread of execution with little to no change to the application code. In spite of this, the process of validating athena multi-process for production took ten months of concentrated effort and is expected to continue for several more months. In general terms, we had two classes of problems in the multi-process port: merging the output fil...
Increasing component functionality via multi-process additive manufacturing
Coronel, Jose L.; Fehr, Katherine H.; Kelly, Dominic D.; Espalin, David; Wicker, Ryan B.
2017-05-01
Additively manufactured components, although extensively customizable, are often limited in functionality. Multi-process additive manufacturing (AM) grants the ability to increase the functionality of components via subtractive manufacturing, wire embedding, foil embedding and pick and place. These processes are scalable to include several platforms ranging from desktop to large area printers. The Multi3D System is highlighted, possessing the capability to perform the above mentioned processes, all while transferring a fabricated component with a robotic arm. Work was conducted to fabricate a patent inspired, printed missile seeker. The seeker demonstrated the advantage of multi-process AM via introduction of the pick and place process. Wire embedding was also explored, with the successful interconnect of two layers of embedded wires in different planes. A final demonstration of a printed contour bracket, served to show the reduction of surface roughness on a printed part is 87.5% when subtractive manufacturing is implemented in tandem with AM. Functionality of the components on all the cases was improved. Results included optical components embedded within the printed housing, wires embedded with interconnection, and reduced surface roughness. These results highlight the improved functionality of components through multi-process AM, specifically through work conducted with the Multi3D System.
Time Optimal Reachability Analysis Using Swarm Verification
DEFF Research Database (Denmark)
Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand
2016-01-01
Time optimal reachability analysis employs model-checking to compute goal states that can be reached from an initial state with a minimal accumulated time duration. The model-checker may produce a corresponding diagnostic trace which can be interpreted as a feasible schedule for many scheduling a...... algorithms work much faster than sequential algorithms, and especially two using combinations of random-depth-first and breadth-first show very promising performance....... search strategies. We develop four swarm algorithms and evaluate them with four models in terms scalability, and time- and memory consumption. Three of these cooperate by exchanging costs of intermediate solutions to prune the search using a branch-and-bound approach. Our results show that swarm...
Probabilistic Reachability for Parametric Markov Models
DEFF Research Database (Denmark)
Hahn, Ernst Moritz; Hermanns, Holger; Zhang, Lijun
2011-01-01
Given a parametric Markov model, we consider the problem of computing the rational function expressing the probability of reaching a given set of states. To attack this principal problem, Daws has suggested to first convert the Markov chain into a finite automaton, from which a regular expression...... is computed. Afterwards, this expression is evaluated to a closed form function representing the reachability probability. This paper investigates how this idea can be turned into an effective procedure. It turns out that the bottleneck lies in the growth of the regular expression relative to the number...... of states (n(log n)).We therefore proceed differently, by tightly intertwining the regular expression computation with its evaluation. This allows us to arrive at an effective method that avoids this blow up in most practical cases. We give a detailed account of the approach, also extending to parametric...
Monitoring Poisson time series using multi-process models
DEFF Research Database (Denmark)
Engebjerg, Malene Dahl Skov; Lundbye-Christensen, Søren; Kjær, Birgitte B.
Surveillance of infectious diseases based on routinely collected public health data is important for at least three reasons: The early detection of an epidemic may facilitate prompt interventions and the seasonal variations and long term trend may be of general epidemiological interest. Furthermore...... aspects of health resource management may also be addressed. In this paper we center on the detection of outbreaks of infectious diseases. This is achieved by a multi-process Poisson state space model taking autocorrelation and overdispersion into account, which has been applied to a data set concerning...
Error detection in GPS observations by means of Multi-process models
DEFF Research Database (Denmark)
Thomsen, Henrik F.
2001-01-01
The main purpose of this article is to present the idea of using Multi-process models as a method of detecting errors in GPS observations. The theory behind Multi-process models, and double differenced phase observations in GPS is presented shortly. It is shown how to model cycle slips in the Multi...
Internal ellipsoidal estimates of reachable set of impulsive control systems
Energy Technology Data Exchange (ETDEWEB)
Matviychuk, Oksana G. [Institute of Mathematics and Mechanics, Russian Academy of Sciences, 16 S. Kovalevskaya str., Ekaterinburg, 620990, Russia and Ural Federal University, 19 Mira str., Ekaterinburg, 620002 (Russian Federation)
2014-11-18
A problem of estimating reachable sets of linear impulsive control system with uncertainty in initial data is considered. The impulsive controls in the dynamical system belong to the intersection of a special cone with a generalized ellipsoid both taken in the space of functions of bounded variation. Assume that an ellipsoidal state constraints are imposed. The algorithms for constructing internal ellipsoidal estimates of reachable sets for such control systems and numerical simulation results are given.
Parallelizing AT with open multi-processing and MPI
Institute of Scientific and Technical Information of China (English)
罗承明; 田顺强; 王坤; 张满洲; 张庆磊; 姜伯承
2015-01-01
Simulating charged particle motion through the elements is necessary to understand modern particle accel-erators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be time-consuming. Open multi-processing (OpenMP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface (MPI) which is based on non-uniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox (AT) for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU.
Minimum-Cost Reachability for Priced Timed Automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas Seidelin
2001-01-01
This paper introduces the model of linearly priced timed automata as an extension of timed automata, with prices on both transitions and locations. For this model we consider the minimum-cost reachability problem: i.e. given a linearly priced timed automaton and a target state, determine...... the minimum cost of executions from the initial state to the target state. This problem generalizes the minimum-time reachability problem for ordinary timed automata. We prove decidability of this problem by offering an algorithmic solution, which is based on a combination of branch-and-bound techniques...... and a new notion of priced regions. The latter allows symbolic representation and manipulation of reachable states together with the cost of reaching them....
A Parametric Modelling Method for Dexterous Finger Reachable Workspaces
Directory of Open Access Journals (Sweden)
Wenzhen Yang
2016-03-01
Full Text Available The well-known algorithms, such as the graphic method, analytical method or numerical method, have some defects when modelling the dexterous finger workspace, which is a significant kinematical feature of dexterous hands and valuable for grasp planning, motion control and mechanical design. A novel modelling method with convenient and parametric performances is introduced to generate the dexterous-finger reachable workspace. This method constructs the geometric topology of the dexterous-finger reachable workspace, and uses a joint feature recognition algorithm to extract the kinematical parameters of the dexterous finger. Compared with graphic, analytical and numerical methods, this parametric modelling method can automatically and conveniently construct a more vivid workspace’ forms and contours of the dexterous finger. The main contribution of this paper is that a workspace-modelling tool with high interactive efficiency is developed for designers to precisely visualize the dexterous-finger reachable workspace, which is valuable for analysing the flexibility of the dexterous finger.
On Reachability for Hybrid Automata over Bounded Time
Brihaye, Thomas; Geeraerts, Gilles; Ouaknine, Joël; Raskin, Jean-François; Worrell, James
2011-01-01
This paper investigates the time-bounded version of the reachability problem for hybrid automata. This problem asks whether a given hybrid automaton can reach a given target location within T time units, where T is a constant rational value. We show that, in contrast to the classical (unbounded) reachability problem, the timed-bounded version is decidable for rectangular hybrid automata provided only non-negative rates are allowed. This class of systems is of practical interest and subsumes, among others, the class of stopwatch automata. We also show that the problem becomes undecidable if either diagonal constraints or both negative and positive rates are allowed.
Mobility Tolerant Firework Routing for Improving Reachability in MANETs
Directory of Open Access Journals (Sweden)
Gen Motoyoshi
2014-03-01
Full Text Available In this paper, we investigate our mobility-assisted and adaptive broadcast routing mechanism, called Mobility Tolerant Firework Routing (MTFR, which utilizes the concept of potentials for routing and improves node reachability, especially in situations with high mobility, by including a broadcast mechanism. We perform detailed evaluations by simulations in a mobile environment and demonstrate the advantages of MTFR over conventional potential-based routing. In particular, we show that MTFR produces better reachability in many aspects at the expense of a small additional transmission delay and intermediate traffic overhead, making MTFR a promising routing protocol and feasible for future mobile Internet infrastructures.
The Effects of Handedness and Reachability on Perceived Distance
Linkenauger, Sally A.; Witt, Jessica K.; Stefanucci, Jeanine K.; Bakdash, Jonathan Z.; Proffitt, Dennis R.
2009-01-01
Previous research has suggested that perceived distances are scaled by the action capabilities of the body. The present studies showed that when "reachability" is constrained due to a difficult grasp required to pick up an object, perceived distance to the object increases. Participants estimated the distances to tools with handle…
Reachability analysis for timed automata using max-plus algebra
DEFF Research Database (Denmark)
Lu, Qi; Madsen, Michael; Milata, Martin
2012-01-01
We show that max-plus polyhedra are usable as a data structure in reachability analysis of timed automata. Drawing inspiration from the extensive work that has been done on difference bound matrices, as well as previous work on max-plus polyhedra in other areas, we develop the algorithms needed t...
Observabilities and reachabilities of nonlinear DEDS and coloring graphs
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
From nonlinear discrete event dynamic systems with the applicablebackground of a large-scale digital integrated circuit, a new conception of coloring graphs on the system is advanced, the necessary and sufficient condition of upper-level observability is given, and the necessary and sufficient condition of respective reachability is simplified and improved.
Reachability Trees for High-level Petri Nets
DEFF Research Database (Denmark)
Jensen, Kurt; Jensen, Arne M.; Jepsen, Leif Obel;
1986-01-01
the necessary analysis methods. In other papers it is shown how to generalize the concept of place- and transition invariants from place/transition nets to high-level Petri nets. Our present paper contributes to this with a generalization of reachability trees, which is one of the other important analysis...
Computations with reachable elements in simple Lie algebras
de Graaf, Willem
2010-01-01
We report on some computations with reachable elements in simple Lie algebras of exceptional type within the SLA package of GAP4. These computations confirm the classification of such elements by Elashvili and Grelaud. Secondly they answer a question from Panyushev. Thirdly they show in what way a recent result of Yakimova for the Lie algebras of classical type extends to the exceptional types.
Reachability for Finite-state Process Algebras Using Horn Clauses
DEFF Research Database (Denmark)
Skrypnyuk, Nataliya; Nielson, Flemming
2013-01-01
In this work we present an algorithm for solving the reachability problem in finite systems that are modelled with process algebras. Our method is based on Static Analysis, in particular, Data Flow Analysis, of the syntax of a process algebraic system with multi-way synchronisation. The results...
Multi-Core BDD Operations for Symbolic Reachability
van Dijk, Tom; Laarman, Alfons; van de Pol, Jan Cornelis; Heljanko, K.; Knottenbelt, W.J.
2012-01-01
This paper presents scalable parallel BDD operations for modern multi-core hardware. We aim at increasing the performance of reachability analysis in the context of model checking. Existing approaches focus on performing multiple independent BDD operations rather than parallelizing the BDD
Winning Concurrent Reachability Games Requires Doubly-Exponential Patience
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Koucký, Michal; Miltersen, Peter Bro
2009-01-01
We exhibit a deterministic concurrent reachability game PURGATORYn with n non-terminal positions and a binary choice for both players in every position so that any positional strategy for Player 1 achieving the value of the game within given isin < 1/2 must use non-zero behavior probabilities tha...
Minimum-Cost Reachability for Priced Timed Automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas Seidelin;
2001-01-01
This paper introduces the model of linearly priced timed automata as an extension of timed automata, with prices on both transitions and locations. For this model we consider the minimum-cost reachability problem: i.e. given a linearly priced timed automaton and a target state, determine the mini......This paper introduces the model of linearly priced timed automata as an extension of timed automata, with prices on both transitions and locations. For this model we consider the minimum-cost reachability problem: i.e. given a linearly priced timed automaton and a target state, determine...... the minimum cost of executions from the initial state to the target state. This problem generalizes the minimum-time reachability problem for ordinary timed automata. We prove decidability of this problem by offering an algorithmic solution, which is based on a combination of branch-and-bound techniques...... and a new notion of priced regions. The latter allows symbolic representation and manipulation of reachable states together with the cost of reaching them....
Optimal Conditional Reachability for Multi-Priced Timed Automata
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2005-01-01
In this paper, we prove decidability of the optimal conditional reachability problem for multi-priced timed automata, an extension of timed automata with multiple cost variables evolving according to given rates for each location. More precisely, we consider the problem of determining the minimal...
The Cost of Parameterized Reachability in Mobile Ad Hoc Networks
Delzanno, Giorgio; Traverso, Riccardo; Zavattaro, Gianluigi
2012-01-01
We investigate the impact of spontaneous movement in the complexity of verification problems for an automata-based protocol model of networks with selective broadcast communication. We first consider reachability of an error state and show that parameterized verification is decidable with polynomial complexity. We then move to richer queries and show how the complexity changes when considering properties with negation or cardinality constraints.
Simple and Faster algorithm for Reachability in a Decremental Directed Graph
Gupta, Manoj
2015-01-01
Consider the problem of maintaining source sink reachability($st$-Reachability), single source reachability(SSR) and strongly connected component(SCC) in an edge decremental directed graph. In particular, we design a randomized algorithm that maintains with high probability: 1) $st$-Reachability in $\\tilde{O}(mn^{4/5})$ total update time. 2) $st$-Reachability in a total update time of $\\tilde{O}(n^{8/3})$ in a dense graph. 3) SSR in a total update time of $\\tilde{O}(m n^{9/10})$. 4) SCC in a ...
Multiprocess 3D printing for increasing component functionality.
MacDonald, Eric; Wicker, Ryan
2016-09-30
Layer-by-layer deposition of materials to manufacture parts-better known as three-dimensional (3D) printing or additive manufacturing-has been flourishing as a fabrication process in the past several years and now can create complex geometries for use as models, assembly fixtures, and production molds. Increasing interest has focused on the use of this technology for direct manufacturing of production parts; however, it remains generally limited to single-material fabrication, which can limit the end-use functionality of the fabricated structures. The next generation of 3D printing will entail not only the integration of dissimilar materials but the embedding of active components in order to deliver functionality that was not possible previously. Examples could include arbitrarily shaped electronics with integrated microfluidic thermal management and intelligent prostheses custom-fit to the anatomy of a specific patient. We review the state of the art in multiprocess (or hybrid) 3D printing, in which complementary processes, both novel and traditional, are combined to advance the future of manufacturing. Copyright © 2016, American Association for the Advancement of Science.
Improved Undecidability Results for Reachability Games on Recursive Timed Automata
Directory of Open Access Journals (Sweden)
Shankara Narayanan Krishna
2014-08-01
Full Text Available We study reachability games on recursive timed automata (RTA that generalize Alur-Dill timed automata with recursive procedure invocation mechanism similar to recursive state machines. It is known that deciding the winner in reachability games on RTA is undecidable for automata with two or more clocks, while the problem is decidable for automata with only one clock. Ouaknine and Worrell recently proposed a time-bounded theory of real-time verification by claiming that restriction to bounded-time recovers decidability for several key decision problem related to real-time verification. We revisited games on recursive timed automata with time-bounded restriction in the hope of recovering decidability. However, we found that the problem still remains undecidable for recursive timed automata with three or more clocks. Using similar proof techniques we characterize a decidability frontier for a generalization of RTA to recursive stopwatch automata.
RAPID: A Reachable Anytime Planner for Imprecisely-sensed Domains
Brunskill, Emma
2012-01-01
Despite the intractability of generic optimal partially observable Markov decision process planning, there exist important problems that have highly structured models. Previous researchers have used this insight to construct more efficient algorithms for factored domains, and for domains with topological structure in the flat state dynamics model. In our work, motivated by findings from the education community relevant to automated tutoring, we consider problems that exhibit a form of topological structure in the factored dynamics model. Our Reachable Anytime Planner for Imprecisely-sensed Domains (RAPID) leverages this structure to efficiently compute a good initial envelope of reachable states under the optimal MDP policy in time linear in the number of state variables. RAPID performs partially-observable planning over the limited envelope of states, and slowly expands the state space considered as time allows. RAPID performs well on a large tutoring-inspired problem simulation with 122 state variables, cor...
A Parametric Modelling Method for Dexterous Finger Reachable Workspaces
2016-01-01
The well-known algorithms, such as the graphic method, analytical method or numerical method, have some defects when modelling the dexterous finger workspace, which is a significant kinematical feature of dexterous hands and valuable for grasp planning, motion control and mechanical design. A novel modelling method with convenient and parametric performances is introduced to generate the dexterous-finger reachable workspace. This method constructs the geometric topology of the dexterous-finge...
Computing and Visualizing Reachable Volumes for Maneuvering Satellites
2011-09-01
Computing and Visualizing Reachable Volumes for Maneuvering Satellites Ming Jiang, Willem H. de Vries, Alexander J. Pertica , Scot S. Olivier...Handbook. Elsevier, 2004. 6. M. Jiang, M. Andereck, A. J. Pertica , and S. S. Olivier. A Scalable Visualization System for Improving Space Situational...Jiang, J. Leek, J. L. Levatin, S. Nikolaev, A. J. Pertica , D. W. Phillion, H. K. Springer, and W. H. de Vries. High-Performance Computer Modeling of
Approximation of Reachable Sets using Optimal Control Algorithms
Baier, Robert; Gerdts, Matthias; Xausa, Ilaria
2013-01-01
To appear; International audience; Numerical experiences with a method for the approximation of reachable sets of nonlinear control systems are reported. The method is based on the formulation of suitable optimal control problems with varying objective functions, whose discretization by Euler's method lead to finite dimensional non-convex nonlinear programs. These are solved by a sequential quadratic programming method. An efficient adjoint method for gradient computation is used to reduce th...
Efficient Reachability Query Evaluation in Large Spatiotemporal Contact Datasets
Shirani-Mehr, Houtan; Shahabi, Cyrus
2012-01-01
With the advent of reliable positioning technologies and prevalence of location-based services, it is now feasible to accurately study the propagation of items such as infectious viruses, sensitive information pieces, and malwares through a population of moving objects, e.g., individuals, mobile devices, and vehicles. In such application scenarios, an item passes between two objects when the objects are sufficiently close (i.e., when they are, so-called, in contact), and hence once an item is initiated, it can penetrate the object population through the evolving network of contacts among objects, termed contact network. In this paper, for the first time we define and study reachability queries in large (i.e., disk-resident) contact datasets which record the movement of a (potentially large) set of objects moving in a spatial environment over an extended time period. A reachability query verifies whether two objects are "reachable" through the evolving contact network represented by such contact datasets. We p...
Optimal Conditional Reachability for Multi-Priced Timed Automata
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2005-01-01
In this paper, we prove decidability of the optimal conditional reachability problem for multi-priced timed automata, an extension of timed automata with multiple cost variables evolving according to given rates for each location. More precisely, we consider the problem of determining the minimal...... cost of reaching a given target state, with respect to some primary cost variable, while respecting upper bound constraints on the remaining (secondary) cost variables. Decidability is proven by constructing a zone-based algorithm that always terminates while synthesizing the optimal cost with a single...... secondary cost variable. The approach is then lifted to any number of secondary cost variables....
Reachability-based impact as a measure for insiderness
DEFF Research Database (Denmark)
Probst, Christian W.; Hansen, René Rydhof
2013-01-01
Insider threats pose a difficult problem for many organisations. While organisations in principle would like to judge the risk posed by a specific insider threat, this is in general not possible. This limitation is caused partly by the lack of models for human behaviour, partly by restrictions...... of impact of an insider, and present different realisations of impact. The suggested approach results in readily usable techniques that allow to get a quick overview of potential insider threats based on locations and assets reachable by employees. We present several variations ranging from pure...
Wafer level reliability monitoring strategy of an advanced multi-process CMOS foundry
Scarpa, Andrea; Tao, Guoqiao; Kuper, F.G.
2000-01-01
In an advanced multi-process CMOS foundry it is strategically important to make use of an optimum reliability monitoring strategy, in order to be able to run well controlled processes. Philips Semiconductors Business Unit Foundries wafer fab MOS4YOU has developed an end-of-line ultra-fast
Wafer level reliability monitoring strategy of an advanced multi-process CMOS foundry
Scarpa, Andrea; Tao, Guoqiao; Kuper, Fred G.
2000-01-01
In an advanced multi-process CMOS foundry it is strategically important to make use of an optimum reliability monitoring strategy, in order to be able to run well controlled processes. Philips Semiconductors Business Unit Foundries wafer fab MOS4YOU has developed an end-of-line ultra-fast reliabilit
Theory of Regions for Control Synthesis without Computing Reachability Graph
Directory of Open Access Journals (Sweden)
Sadok Rezig
2017-03-01
Full Text Available This paper addresses the design of Petri net (PN supervisor using the theory of regions for forbidden state problem with a set of general mutual exclusion constraints. In fact, as any method of supervisory control based on reachability graph, the theory of regions suffers from a technical obstacle in control synthesis, which is the necessity of computing the graph at each iteration step. Moreover, based on the reachability graph, which may contain a large number of states, with respect to the structural size of the system, the computation of PN controllers becomes harder and even impossible. The main contribution of this paper, compared to previous works, is the development of a control synthesis method in order to decrease significantly the computation cost of the PN supervisor. Thus, based on PN properties and mathematical concepts, the proposed methodology provides an optimal PN supervisor for bounded Petri nets following the interpretation of the theory of regions. Finally, case studies are solved by CPLEX software to compare our new control policy with previous works which use the theory of regions for control synthesis.
Extensions of Clarke's proximal characterization for reachable mappings of differential inclusions
Donchev, T.; Dontchev, A. L.
2008-12-01
In this paper we show that Clarke's proximal characterization for reachable mappings of Lipschitz continuous differential inclusions is valid for a larger class of continuous and locally one-side Kamke continuous inclusions. We also give a new proximal characterization for reachable mappings of upper semi-continuous differential inclusions.
Language-Constraint Reachability Learning in Probabilistic Graphs
Taranto, Claudio; Esposito, Floriana
2012-01-01
The probabilistic graphs framework models the uncertainty inherent in real-world domains by means of probabilistic edges whose value quantifies the likelihood of the edge existence or the strength of the link it represents. The goal of this paper is to provide a learning method to compute the most likely relationship between two nodes in a framework based on probabilistic graphs. In particular, given a probabilistic graph we adopted the language-constraint reachability method to compute the probability of possible interconnections that may exists between two nodes. Each of these connections may be viewed as feature, or a factor, between the two nodes and the corresponding probability as its weight. Each observed link is considered as a positive instance for its corresponding link label. Given the training set of observed links a L2-regularized Logistic Regression has been adopted to learn a model able to predict unobserved link labels. The experiments on a real world collaborative filtering problem proved tha...
Reachability by paths of bounded curvature in a convex polygon
Ahn, Heekap
2012-01-01
Let B be a point robot moving in the plane, whose path is constrained to forward motions with curvature at most 1, and let P be a convex polygon with n vertices. Given a starting configuration (a location and a direction of travel) for B inside P, we characterize the region of all points of P that can be reached by B, and show that it has complexity O(n). We give an O(n2) time algorithm to compute this region. We show that a point is reachable only if it can be reached by a path of type CCSCS, where C denotes a unit circle arc and S denotes a line segment. © 2011 Elsevier B.V.
Reachable set modeling and engagement analysis of exoatmospheric interceptor
Institute of Scientific and Technical Information of China (English)
Chai Hua; Liang Yangang; Chen Lei; Tang Guojin
2014-01-01
A novel reachable set (RS) model is developed within a framework of exoatmospheric interceptor engagement analysis. The boost phase steering scheme and trajectory distortion mech-anism of the interceptor are firstly explored. A mathematical model of the distorted RS is then for-mulated through a dimension–reduction analysis. By treating the outer boundary of the RS on sphere surface as a spherical convex hull, two relevant theorems are proposed and the RS envelope is depicted by the computational geometry theory. Based on RS model, the algorithms of intercept window analysis and launch parameters determination are proposed, and numerical simulations are carried out for interceptors with different energy or launch points. Results show that the proposed method can avoid intensive on-line computation and provide an accurate and effective approach for interceptor engagement analysis. The suggested RS model also serves as a ready reference to other related problems such as interceptor effectiveness evaluation and platform disposition.
Reachable set modeling and engagement analysis of exoatmospheric interceptor
Directory of Open Access Journals (Sweden)
Chai Hua
2014-12-01
Full Text Available A novel reachable set (RS model is developed within a framework of exoatmospheric interceptor engagement analysis. The boost phase steering scheme and trajectory distortion mechanism of the interceptor are firstly explored. A mathematical model of the distorted RS is then formulated through a dimension–reduction analysis. By treating the outer boundary of the RS on sphere surface as a spherical convex hull, two relevant theorems are proposed and the RS envelope is depicted by the computational geometry theory. Based on RS model, the algorithms of intercept window analysis and launch parameters determination are proposed, and numerical simulations are carried out for interceptors with different energy or launch points. Results show that the proposed method can avoid intensive on-line computation and provide an accurate and effective approach for interceptor engagement analysis. The suggested RS model also serves as a ready reference to other related problems such as interceptor effectiveness evaluation and platform disposition.
McMahon, Troy
2014-09-01
© 2014 IEEE. Reachable volumes are a geometric representation of the regions the joints of a robot can reach. They can be used to generate constraint satisfying samples for problems including complicated linkage robots (e.g. closed chains and graspers). They can also be used to assist robot operators and to help in robot design.We show that reachable volumes have an O(1) complexity in unconstrained problems as well as in many constrained problems. We also show that reachable volumes can be computed in linear time and that reachable volume samples can be generated in linear time in problems without constraints. We experimentally validate reachable volume sampling, both with and without constraints on end effectors and/or internal joints. We show that reachable volume samples are less likely to be invalid due to self-collisions, making reachable volume sampling significantly more efficient for higher dimensional problems. We also show that these samples are easier to connect than others, resulting in better connected roadmaps. We demonstrate that our method can be applied to 262-dof, multi-loop, and tree-like linkages including combinations of planar, prismatic and spherical joints. In contrast, existing methods either cannot be used for these problems or do not produce good quality solutions.
Energy Technology Data Exchange (ETDEWEB)
Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M
2004-08-01
To improve phytoremediation processes, multiple techniques that comprise different aspects of contaminant removal from soils have been combined. Using creosote as a test contaminant, a multi-process phytoremediation system composed of physical (volatilization), photochemical (photooxidation) and microbial remediation, and phytoremediation (plant-assisted remediation) processes was developed. The techniques applied to realize these processes were land-farming (aeration and light exposure), introduction of contaminant degrading bacteria, plant growth promoting rhizobacteria (PGPR), and plant growth of contaminant-tolerant tall fescue (Festuca arundinacea). Over a 4-month period, the average efficiency of removal of 16 priority PAHs by the multi-process remediation system was twice that of land-farming, 50% more than bioremediation alone, and 45% more than phytoremediation by itself. Importantly, the multi-process system was capable of removing most of the highly hydrophobic, soil-bound PAHs from soil. The key elements for successful phytoremediation were the use of plant species that have the ability to proliferate in the presence of high levels of contaminants and strains of PGPR that increase plant tolerance to contaminants and accelerate plant growth in heavily contaminated soils. The synergistic use of these approaches resulted in rapid and massive biomass accumulation of plant tissue in contaminated soil, putatively providing more active metabolic processes, leading to more rapid and more complete removal of PAHs. - Persistent PAH contaminants in soils can be removed more completely and rapidly by using multiple remediation processes.
Zimovets, Artem; Matviychuk, Alexander; Ushakov, Vladimir
2016-12-01
The paper presents two different approaches to reduce the time of computer calculation of reachability sets. First of these two approaches use different data structures for storing the reachability sets in the computer memory for calculation in single-threaded mode. Second approach is based on using parallel algorithms with reference to the data structures from the first approach. Within the framework of this paper parallel algorithm of approximate reachability set calculation on computer with SMP-architecture is proposed. The results of numerical modelling are presented in the form of tables which demonstrate high efficiency of parallel computing technology and also show how computing time depends on the used data structure.
Iterable Forward Reachability Analysis of Monitor-DPNs
Directory of Open Access Journals (Sweden)
Benedikt Nordhoff
2013-09-01
Full Text Available There is a close connection between data-flow analysis and model checking as observed and studied in the nineties by Steffen and Schmidt. This indicates that automata-based analysis techniques developed in the realm of infinite-state model checking can be applied as data-flow analyzers that interpret complex control structures, which motivates the development of such analysis techniques for ever more complex models. One approach proposed by Esparza and Knoop is based on computation of predecessor or successor sets for sets of automata configurations. Our goal is to adapt and exploit this approach for analysis of multi-threaded Java programs. Specifically, we consider the model of Monitor-DPNs for concurrent programs. Monitor-DPNs precisely model unbounded recursion, dynamic thread creation, and synchronization via well-nested locks with finite abstractions of procedure- and thread-local state. Previous work on this model showed how to compute regular predecessor sets of regular configurations and tree-regular successor sets of a fixed initial configuration. By combining and extending different previously developed techniques we show how to compute tree-regular successor sets of tree-regular sets. Thereby we obtain an iterable, lock-sensitive forward reachability analysis. We implemented the analysis for Java programs and applied it to information flow control and data race detection.
On divisible weighted Dynkin diagrams and reachable elements
Panyushev, Dmitri I
2010-01-01
Let D(e) denote the weighted Dynkin diagram of a nilpotent element $e$ in complex simple Lie algebra $\\g$. We say that D(e) is divisible if D(e)/2 is again a weighted Dynkin diagram. (That is, a necessary condition for divisibility is that $e$ is even.) The corresponding pair of nilpotent orbits is said to be friendly. In this note, we classify the friendly pairs and describe some of their properties. We also observe that any subalgebra sl(3) in $\\g$ determines a friendly pair. Such pairs are called A2-pairs. It turns out that the centraliser of the lower orbit in an A2-pair has some remarkable properties. Let $Gx$ be such an orbit and $h$ a characteristic of $x$. Then $h$ determines the Z-grading of the centraliser $z=z(x)$. We prove that $z$ is generated by the Levi subalgebra $z(0)$ and two elements in $z(1)$. In particular, (1) the nilpotent radical of $z$ is generated by $z(1)$ and (2) $x\\in [z,z]$. The nilpotent elements having the last property are called reachable.
Liveness and Reachability Analysis of BPMN Process Models
Directory of Open Access Journals (Sweden)
Anass Rachdi
2016-06-01
Full Text Available Business processes are usually defined by business experts who require intuitive and informal graphical notations such as BPMN (Business Process Management Notation for documenting and communicating their organization activities and behavior. However, BPMN has not been provided with a formal semantics, which limits the analysis of BPMN models to using solely informal techniques such as simulation. In order to address this limitation and use formal verification, it is necessary to define a certain “mapping” between BPMN and a formal language such as Concurrent Sequential Processes (CSP and Petri Nets (PN. This paper proposes a method for the verification of BPMN models by defining formal semantics of BPMN in terms of a mapping to Time Petri Nets (TPN, which are equipped with very efficient analytical techniques. After the translation of BPMN models to TPN, verification is done to ensure that some functional properties are satisfied by the model under investigation, namely liveness and reachability properties. The main advantage of our approach over existing ones is that it takes into account the time components in modeling Business process models. An example is used throughout the paper to illustrate the proposed method.
Computing and Visualizing Reachable Volumes for Maneuvering Satellites
Energy Technology Data Exchange (ETDEWEB)
Jiang, M; de Vries, W H; Pertica, A J; Olivier, S S
2011-09-11
Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo approach to computing the RV for a given object. Essentially, our approach samples all possible trajectories by randomizing thrust-vectors, thrust magnitudes and time of burn. At any given instance, the distribution of the 'point-cloud' of the virtual particles defines the RV. For short orbital time-scales, the temporal evolution of the point-cloud can result in complex, multi-reentrant manifolds. Visualization plays an important role in gaining insight and understanding into this complex and evolving manifold. In the second part of this paper, we focus on how to effectively visualize the large number of virtual trajectories and the computed RV. We present a real-time out-of-core rendering technique for visualizing the large number of virtual trajectories. We also examine different techniques for visualizing the computed volume of probability density distribution, including volume slicing, convex hull and isosurfacing. We compare and contrast these techniques in terms of computational cost and visualization effectiveness, and describe the main implementation issues encountered during our development process. Finally, we will present some of the results from our end-to-end system for computing and visualizing RVs using examples of maneuvering satellites.
On some questions in computer modeling of the reachability sets constructing problems
Ushakov, V. N.; Parshikov, G. V.; Matviychuk, A. R.
2016-10-01
The research considers the problem of constructing the reachability sets of non-linear dynamical system in n-dimensional Euclidean space on the fixed time interval. The approximate solution methods of the reachability sets constructing are considered in this research as well as the accuracy estimation for this methods is given. The research contains the computational experiments on computer modeling of described reachability sets constructing methods, which use the algorithms implemented for two computation technologies CPU as well as GPU (using CUDA technology). In this research the description and comparison of approaches to the computer modeling of the problem are given. Furthermore, the CPU-based computer modeling result comparison with the result obtained on GPU based on CUDA technology are presented. Besides, this research discusses some the side issues appeared during computer modeling, the issues raised during the computer algorithms implementation, as well as the ways to eliminate these issues or reduce their impact.
Li, Jun; Lu, Dawei; Luo, Zhihuang; Laflamme, Raymond; Peng, Xinhua; Du, Jiangfeng
2016-07-01
Precisely characterizing and controlling realistic quantum systems under noises is a challenging frontier in quantum sciences and technologies. In developing reliable controls for open quantum systems, one is often confronted with the problem of the lack of knowledge on the system controllability. The purpose of this paper is to give a numerical approach to this problem, that is, to approximately compute the reachable set of states for coherently controlled quantum Markovian systems. The approximation consists of setting both upper and lower bounds for system's reachable region of states. Furthermore, we apply our reachability analysis to the control of the relaxation dynamics of a two-qubit nuclear magnetic resonance spin system. We implement some experimental tasks of quantum state engineering in this open system at a near optimal performance in view of purity: e.g., increasing polarization and preparing pseudopure states. These results demonstrate the usefulness of our theory and show interesting and promising applications of environment-assisted quantum dynamics.
DEFF Research Database (Denmark)
Le Moullec, Yannick
2011-01-01
-In-Progress paper we introduce our set of high-level estimation models for Area-Time costs of applications mapped onto FPGA-based multiprocessing reconfigurable architectures. In particular, we suggest models for static and dynamic implementations, taking various internal and external architectural elements...
Goreac, D
2010-01-01
We aim at characterizing viability, invariance and some reachability properties of controlled piecewise deterministic Markov processes (PDMPs). Using analytical methods from the theory of viscosity solutions, we establish criteria for viability and invariance in terms of the first order normal cone. We also investigate reachability of arbitrary open sets. The method is based on viscosity techniques and duality for some associated linearized problem. The theoretical results are applied to general On/Off systems, Cook's model for haploinssuficiency, and a stochastic model for bacteriophage lambda.
Shared I/O components for the ATLAS multi-processing framework
van Gemmeren, Peter; The ATLAS collaboration
2017-01-01
ATLAS uses its multi-processing framework AthenaMP for an increasing number of workflows, including simulation, reconstruction and event data filtering (derivation). After serial initialization, AthenaMP forks worker processes that then process events in parallel, with each worker reading data individually and producing its own output. This mode, however, has inefficiencies: 1) The worker no longer reads events sequentially, which negatively affects data caching strategies at the storage backend. 2) For its non-RAW data ATLAS uses ROOT and compresses across 10-100 events. Workers will only need a subsample of these events, but have to read and decompress the complete buffers. 3) Output files from the individual workers need to be merged in a separate, serial process. 4) Propagating metadata describing the complete event sample through several workers is nontrivial. To address these shortcomings, ATLAS has developed shared reader and writer components presented in this paper. With the shared reader, a single p...
Safe landing area determination for a Moon lander by reachability analysis
Arslantaş, Yunus Emre; Oehlschlägel, Thimo; Sagliano, Marco
2016-11-01
In the last decades developments in space technology paved the way to more challenging missions like asteroid mining, space tourism and human expansion into the Solar System. These missions result in difficult tasks such as guidance schemes for re-entry, landing on celestial bodies and implementation of large angle maneuvers for spacecraft. There is a need for a safety system to increase the robustness and success of these missions. Reachability analysis meets this requirement by obtaining the set of all achievable states for a dynamical system starting from an initial condition with given admissible control inputs of the system. This paper proposes an algorithm for the approximation of nonconvex reachable sets (RS) by using optimal control. Therefore subset of the state space is discretized by equidistant points and for each grid point a distance function is defined. This distance function acts as an objective function for a related optimal control problem (OCP). Each infinite dimensional OCP is transcribed into a finite dimensional Nonlinear Programming Problem (NLP) by using Pseudospectral Methods (PSM). Finally, the NLPs are solved using available tools resulting in approximated reachable sets with information about the states of the dynamical system at these grid points. The algorithm is applied on a generic Moon landing mission. The proposed method computes approximated reachable sets and the attainable safe landing region with information about propellant consumption and time.
A Joint Criterion for Reachability and Observability of Nonuniformly Sampled Discrete Systems
Fúster-Sabater, Amparo
2010-01-01
A joint characterization of reachability (controllability) and observability (constructibility) for linear SISO nonuniformly sampled discrete systems is presented. The work generalizes to the nonuniform sampling the criterion known for the uniform sampling. Emphasis is on the nonuniform sampling sequence, which is believed to be an additional element for analysis and handling of discrete systems.
Indian Academy of Sciences (India)
Deepak Swami; P K Sharma; C S P Ojha
2014-12-01
In this paper, we have studied the behaviour of reactive solute transport through stratified porous medium under the influence of multi-process nonequilibrium transport model. Various experiments were carried out in the laboratory and the experimental breakthrough curves were observed at spatially placed sampling points for stratified porous medium. Batch sorption studies were also performed to estimate the sorption parameters of the material used in stratified aquifer system. The effects of distance dependent dispersion and tailing are visible in the experimental breakthrough curves. The presence of physical and chemical non-equilibrium are observed from the pattern of breakthrough curves. Multi-process non-equilibrium model represents the combined effect of physical and chemical non-ideality in the stratified aquifer system. The results show that the incorporation of distance dependent dispersivity in multi-process non-equilibrium model provides best fit of observed data through stratified porous media. Also, the exponential distance dependent dispersivity is more suitable for large distances and at small distances, linear or constant dispersivity function can be considered for simulating reactive solute in stratified porous medium.
Impact Of Various Factors On Probability Of Reachability In Manet: A Survey
Directory of Open Access Journals (Sweden)
Chander Kuma
2011-10-01
Full Text Available The Probability of Reachability (POR is defined as fraction of possible reachable routes to all possible routes between all different sources to all different destinations. In network like Mobile Ad-hoc Network (MANET adequate level of POR is desirable for its smooth functioning. Its value depends upon various factors such as Transmission Range (T, Number of Nodes (N, node mobility, channel fading, shape and size of the region where the ad-hoc network is to be deployed. To find the impact of N,T, size and shape on the value of POR, a shortest path routing algorithm was implemented in MATLAB and effect of the above said parameters was studied. We observe significant impact of varying not only N and T but also of varying size and shape of the region on the POR values.
Reachability analysis of a class of Petri nets using place invariants and siphons
Directory of Open Access Journals (Sweden)
Zhi Wu Li
2013-07-01
Full Text Available This paper proposes a novel and computationally efficient approach to deal with the reachability problem by using place invariants and strict minimal siphons for a class of Petri nets called pipe-line nets (PLNs. First, in a PLN with an appropriate initial marking, the set of invariant markings and the set of strict minimal siphons are enumerated. Then a sufficient and necessary condition is developed to decide whether a marking is spurious by analysing the number of tokens in operation places of any strict minimal siphon and their bounds. Furthermore, an algorithm that generates the reachable markings by removing all the spurious markings from the set of invariant markings is proposed. Finally, experimental results show the efficiency of the proposed method.
Approximating the Value of a Concurrent Reachability Game in the Polynomial Time Hierarchy
DEFF Research Database (Denmark)
Frederiksen, Søren Kristoffer Stiil; Miltersen, Peter Bro
2013-01-01
We show that the value of a finite-state concurrent reachability game can be approximated to arbitrary precision in TFNP[NP], that is, in the polynomial time hierarchy. Previously, no better bound than PSPACE was known for this problem. The proof is based on formulating a variant of the state red...... reduction algorithm for Markov chains using arbitrary precision floating point arithmetic and giving a rigorous error analysis of the algorithm....
Periodically-Scheduled Controller Analysis using Hybrid Systems Reachability and Continuization
2015-12-01
algorithm is run, and actuator outputs are set. The physical world , on the other hand, evolves continuously. Models of the physical world may be given...An extra clock variable, c, is added to the hybrid automaton that ticks at rate one (ċ = 1). When the clock reaches the period, a transition is...Preliminary Reachability Analysis Although hybrid automata can model real-time scheduled controllers and plants as shown above, an important factor is
Multicore in production: advantages and limits of the multiprocess approach in the ATLAS experiment
Binet, S.; Calafiura, P.; Jha, M. K.; Lavrijsen, W.; Leggett, C.; Lesny, D.; Severini, H.; Smith, D.; Snyder, S.; Tatarkhanov, M.; Tsulaia, V.; VanGemmeren, P.; Washbrook, A.
2012-06-01
The shared memory architecture of multicore CPUs provides HEP developers with the opportunity to reduce the memory footprint of their applications by sharing memory pages between the cores in a processor. ATLAS pioneered the multi-process approach to parallelize HEP applications. Using Linux fork() and the Copy On Write mechanism we implemented a simple event task farm, which allowed us to achieve sharing of almost 80% of memory pages among event worker processes for certain types of reconstruction jobs with negligible CPU overhead. By leaving the task of managing shared memory pages to the operating system, we have been able to parallelize large reconstruction and simulation applications originally written to be run in a single thread of execution with little to no change to the application code. The process of validating AthenaMP for production took ten months of concentrated effort and is expected to continue for several more months. Besides validating the software itself, an important and time-consuming aspect of running multicore applications in production was to configure the ATLAS distributed production system to handle multicore jobs. This entailed defining multicore batch queues, where the unit resource is not a core, but a whole computing node; monitoring the output of many event workers; and adapting the job definition layer to handle computing resources with different event throughputs. We will present scalability and memory usage studies, based on data gathered both on dedicated hardware and at the CERN Computer Center.
MultiNoC: A Multiprocessing System Enabled by a Network on Chip
Mello, Aline; Calazans, Ney; Moraes, Fernando
2011-01-01
The MultiNoC system implements a programmable on-chip multiprocessing platform built on top of an efficient, low area overhead intra-chip interconnection scheme. The employed interconnection structure is a Network on Chip, or NoC. NoCs are emerging as a viable alternative to increasing demands on interconnection architectures, due to the following characteristics: (i) energy efficiency and reliability; (ii) scalability of bandwidth, when compared to traditional bus architectures; (iii) reusability; (iv) distributed routing decisions. An external host computer feeds MultiNoC with application instructions and data. After this initialization procedure, MultiNoC executes some algorithm. After finishing execution of the algorithm, output data can be read back by the host. Sequential or parallel algorithms conveniently adapted to the MultiNoC structure can be executed. The main motivation to propose this design is to enable the investigation of current trends to increase the number of embedded processors in SoCs, l...
N-dimensional switch function for energy conservation in multiprocess reaction dynamics.
Mogo, César; Brandão, João
2016-06-15
The MReaDy program was designed for studying Multiprocess Reactive Dynamic systems, that is, complex chemical systems involving different and concurrent reactions. It builds a global potential energy surface integrating a variety of potential energy surfaces, each one of them representing an elementary reaction expected to play a role in the chemical process. For each elementary reaction, energy continuity problems may happen in the transition between potential energy surfaces due to differences in the functional form for each of the fragments, especially if built by different authors. A N-dimensional switch function is introduced in MReaDy in order to overcome such a problem. As an example, results of a collision trajectory calculation for H2 + OH → H3 O are presented, showing smooth transition in the potential energy, leading to conservation in the total energy. Calculations for a hydrogen combustion system from 1000 K up to 4000 K shows a variation of 0.012% when compared to the total energy of the system. © 2016 Wiley Periodicals, Inc.
Model Predictive Control considering Reachable Range of Wheels for Leg / Wheel Mobile Robots
Suzuki, Naito; Nonaka, Kenichiro; Sekiguchi, Kazuma
2016-09-01
Obstacle avoidance is one of the important tasks for mobile robots. In this paper, we study obstacle avoidance control for mobile robots equipped with four legs comprised of three DoF SCARA leg/wheel mechanism, which enables the robot to change its shape adapting to environments. Our previous method achieves obstacle avoidance by model predictive control (MPC) considering obstacle size and lateral wheel positions. However, this method does not ensure existence of joint angles which achieves reference wheel positions calculated by MPC. In this study, we propose a model predictive control considering reachable mobile ranges of wheels positions by combining multiple linear constraints, where each reachable mobile range is approximated as a convex trapezoid. Thus, we achieve to formulate a MPC as a quadratic problem with linear constraints for nonlinear problem of longitudinal and lateral wheel position control. By optimization of MPC, the reference wheel positions are calculated, while each joint angle is determined by inverse kinematics. Considering reachable mobile ranges explicitly, the optimal joint angles are calculated, which enables wheels to reach the reference wheel positions. We verify its advantages by comparing the proposed method with the previous method through numerical simulations.
Longitudinal evaluation of upper extremity reachable workspace in ALS by Kinect sensor.
de Bie, Evan; Oskarsson, Bjorn; Joyce, Nanette C; Nicorici, Alina; Kurillo, Gregorij; Han, Jay J
2017-02-01
Our objective was to evaluate longitudinal changes in Microsoft Kinect measured upper extremity reachable workspace relative surface area (RSA) versus the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), ALSFRS-R upper extremity sub-scale and Forced Vital Capacity (FVC) in a cohort of patients diagnosed with amyotrophic lateral sclerosis (ALS). Ten patients diagnosed with ALS (ages 52-76 years, ALSFRS-R: 8-41 at entry) were tested using single 3D depth sensor, Microsoft Kinect, to measure reachable workspace RSA across five visits spanning one year. Changes in RSA, ALSFRS-R, ALSFRS-R upper extremity sub-scale, and FVC were assessed using a linear mixed model. Results showed that upper lateral quadrant RSA declined significantly in one year by approximately 19% (p <0.01) while all other quadrants and total RSA did not change significantly in this time-period. Simultaneously, ALSFRS-R upper extremity sub-scale worsened significantly by 25% (p <0.01). In conclusion, upper extremity reachable workspace RSA as a novel ALS outcome measure is capable of objectively quantifying declines in upper extremity ability over time in patients with ALS with more granularity than other common outcome measures. RSA may serve as a clinical endpoint for the evaluation of upper extremity targeted therapeutics.
Reachability Analysis of Time Basic Petri Nets: a Time Coverage Approach
Bellettini, Carlo
2011-01-01
We introduce a technique for reachability analysis of Time-Basic (TB) Petri nets, a powerful formalism for real- time systems where time constraints are expressed as intervals, representing possible transition firing times, whose bounds are functions of marking's time description. The technique consists of building a symbolic reachability graph relying on a sort of time coverage, and overcomes the limitations of the only available analyzer for TB nets, based in turn on a time-bounded inspection of a (possibly infinite) reachability-tree. The graph construction algorithm has been automated by a tool-set, briefly described in the paper together with its main functionality and analysis capability. A running example is used throughout the paper to sketch the symbolic graph construction. A use case describing a small real system - that the running example is an excerpt from - has been employed to benchmark the technique and the tool-set. The main outcome of this test are also presented in the paper. Ongoing work, ...
Energy Technology Data Exchange (ETDEWEB)
Oishi, Meeko M.
2006-08-01
This document describes new advances in hybrid reachability techniques accomplished during the course of a one-year Truman Postdoctoral Fellowship. These techniques provide guarantees of safety in complex systems, which is especially important in high-risk, expensive, or safety-critical systems. My work focused on new approaches to two specific problems motivated by real-world issues in complex systems: (1) multi-objective controller synthesis, and (2) control for recovery from error. Regarding the first problem, a novel application of reachability analysis allowed controller synthesis in a single step to achieve (a) safety, (b) stability, and (c) prevent input saturation. By extending the state to include the input parameters, constraints for stability, saturation, and envelope protection are incorporated into a single reachability analysis. Regarding the second problem, a new approach to the problem of recovery provides (a) states from which recovery is possible, and (b) controllers to guide the system during a recovery maneuver from an error state to a safe state in minimal time. Results are computed in both problems on nonlinear models of single longitudinal aircraft dynamics and two-aircraft lateral collision avoidance dynamics.
Multi-process herbicide transport in structured soil columns: experiments and model analysis.
Köhne, J Maximilian; Köhne, Sigrid; Simůnek, Jirka
2006-05-01
Model predictions of pesticide transport in structured soils are complicated by multiple processes acting concurrently. In this study, the hydraulic, physical, and chemical nonequilibrium (HNE, PNE, and CNE, respectively) processes governing herbicide transport under variably saturated flow conditions were studied. Bromide (Br-), isoproturon (IPU, 3-(4-isoprpylphenyl)-1,1-dimethylurea) and terbuthylazine (TER, N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine) were applied to two soil columns. An aggregated Ap soil column and a macroporous, aggregated Ah soil column were irrigated at a rate of 1 cm h(-1) for 3 h. Two more irrigations at the same rate and duration followed in weekly intervals. Nonlinear (Freundlich) equilibrium and two-site kinetic sorption parameters were determined for IPU and TER using batch experiments. The observed water flow and Br- transport were inversely simulated using mobile-immobile (MIM), dual-permeability (DPM), and combined triple-porosity (DP-MIM) numerical models implemented in HYDRUS-1D, with improving correspondence between empirical data and model results. Using the estimated HNE and PNE parameters together with batch-test derived equilibrium sorption parameters, the preferential breakthrough of the weakly adsorbed IPU in the Ah soil could be reasonably well predicted with the DPM approach, whereas leaching of the strongly adsorbed TER was predicted less well. The transport of IPU and TER through the aggregated Ap soil could be described consistently only when HNE, PNE, and CNE were simultaneously accounted for using the DPM. Inverse parameter estimation suggested that two-site kinetic sorption in inter-aggregate flow paths was reduced as compared to within aggregates, and that large values for the first-order degradation rate were an artifact caused by irreversible sorption. Overall, our results should be helpful to enhance the understanding and modeling of multi-process pesticide transport through structured soils
DEFF Research Database (Denmark)
Le Moullec, Yannick
2011-01-01
VLSI technological advances provide designers with more and more powerful and flexible platforms such as reconfigurable heterogeneous multiprocessing systems based on FPGAs. At the same time, the applications which are to be implemented onto such platforms are increasingly more and more complex...... into account. We believe that such models could be used for rapidly comparing implementation alternatives at a high level of abstraction and for guiding the designer during the (pre)analysis phase of the design flow for the implementation of e.g. SDR platforms....
A Survey of Reachability Trees of Unbounded Petri Nets%无界Petri网的可达树的综述
Institute of Scientific and Technical Information of China (English)
干梦迪; 王寿光; 周孟初; 李俊; 李月
2015-01-01
Petri 网自提出以来得到了学术界和工业界的广泛关注。 Petri 网系统的可达性是最基本性质之一。系统的其他相关性质都可以通过可达性进行分析。利用等价的有限可达树来研究无界Petri 网可达性，依然是一个开放性问题。该研究可以追溯到40年前，但由于问题本身的复杂性和难度太大，直到最近20年，经过国内外诸多学者的不懈努力，才逐渐取得了一些阶段性的成果和部分突破。本文回顾了近40年来国内外学者为彻底解决该问题作出的贡献。重点对4种开创性的研究成果展开讨论，分别为有限可达树、扩展可达树、改进可达树及新型改进可达树。探讨了今后无界Petri网可达性问题的研究方向。%In recent years both industry and academia have paid much attention to the theory and applications of Petri nets. Reachability is a basic property of a Petri net, and many properties can be analyzed via it. However, analyzing the reachability problem of unbounded Petri nets by finite reachability trees has been an open problem since the inception of Petri nets. Researchers began to study the problem of reachability trees over 40 years ago. However, they made only limited progress over the last 20 years due to its complexity and diﬃculty. We present an overview of some important contributions toward its solution. The focuses are on four novel finite reachability trees: finite reachability tree (FRT), augmented reachability tree (ART), modified reachability tree (MRT) and new modified reachailbity tree (NMRT). The paper concludes with a discussion of directions for future research of the reachability problem of unbounded Petri nets.
A Forward Reachability Algorithm for Bounded Timed-Arc Petri Nets
DEFF Research Database (Denmark)
David, Alexandre; Jacobsen, Lasse; Jacobsen, Morten
2012-01-01
in the presence of monotonicity-breaking features like age invariants and inhibitor arcs. We implement the algorithm within the model-checkerTAPAAL and the experimental results document an encouraging performance compared to verification approaches that translate TAPN models to UPPAAL timed automata.......Timed-arc Petri nets (TAPN) are a well-known time extension of thePetri net model and several translations to networks of timedautomata have been proposed for this model.We present a direct, DBM-basedalgorithm for forward reachability analysis of bounded TAPNs extended with transport arcs...
Multi-scale modeling of follicular ovulation as a reachability problem
Echenim, Nki; Sorine, Michel
2007-01-01
During each ovarian cycle, only a definite number of follicles ovulate, while the others undergo a degeneration process called atresia. We have designed a multi-scale mathematical model where ovulation and atresia result from a hormonal controlled selection process. A 2D-conservation law describes the age and maturity structuration of the follicular cell population. In this paper, we focus on the operating mode of the control, through the study of the characteristics of the conservation law. We describe in particular the set of microscopic initial conditions leading to the macroscopic phenomenon of either ovulation or atresia, in the framework of backwards reachable sets theory.
Transition-based deadlock control policy using reachability graph for flexible manufacturing systems
Directory of Open Access Journals (Sweden)
Xiuyan Zhang
2016-02-01
Full Text Available Most existing deadlock prevention policies deal with deadlock problems arising in flexible manufacturing systems modeled with Petri nets by adding control places. Based on the reachability graph analysis, this article proposes a novel deadlock control policy that recovers the system from deadlock and livelock states to legal states and reaches the same number of states as the original plant model by adding control transitions. In order to reduce the structural complexity of the supervisor, a set covering approach is developed to minimize the number of control transitions. Finally, two flexible manufacturing system examples are presented to illustrate the proposed approach.
Directory of Open Access Journals (Sweden)
Elise Cormie-Bowins
2012-10-01
Full Text Available We consider the problem of computing reachability probabilities: given a Markov chain, an initial state of the Markov chain, and a set of goal states of the Markov chain, what is the probability of reaching any of the goal states from the initial state? This problem can be reduced to solving a linear equation Ax = b for x, where A is a matrix and b is a vector. We consider two iterative methods to solve the linear equation: the Jacobi method and the biconjugate gradient stabilized (BiCGStab method. For both methods, a sequential and a parallel version have been implemented. The parallel versions have been implemented on the compute unified device architecture (CUDA so that they can be run on a NVIDIA graphics processing unit (GPU. From our experiments we conclude that as the size of the matrix increases, the CUDA implementations outperform the sequential implementations. Furthermore, the BiCGStab method performs better than the Jacobi method for dense matrices, whereas the Jacobi method does better for sparse ones. Since the reachability probabilities problem plays a key role in probabilistic model checking, we also compared the implementations for matrices obtained from a probabilistic model checker. Our experiments support the conjecture by Bosnacki et al. that the Jacobi method is superior to Krylov subspace methods, a class to which the BiCGStab method belongs, for probabilistic model checking.
Iachini, Tina; Ruggiero, Gennaro; Ruotolo, Francesco; Schiano di Cola, Armando; Senese, Vincenzo Paolo
2015-09-01
Although the effects of several personality factors on interpersonal space (i.e. social space within personal comfort area) are well documented, it is not clear whether they also extend to peripersonal space (i.e. reaching space). Indeed, no study has directly compared these spaces in relation to personality and anxiety factors even though such a comparison would help to clarify to what extent they share similar mechanisms and characteristics. The aim of the present paper was to investigate whether personality dimensions and anxiety levels are associated with reaching and comfort distances. Seventy university students (35 females) were administered the Big Five Questionnaire and the State-Trait Anxiety Inventory; afterwards, they had to provide reachability- and comfort-distance judgments towards human confederates while standing still (passive) or walking towards them (active). The correlation analyses showed that both spaces were positively related to anxiety and negatively correlated with the Dynamism in the active condition. Moreover, in the passive condition higher Emotional Stability was related to shorter comfort distance, while higher cognitive Openness was associated with shorter reachability distance. The implications of these results are discussed.
Directory of Open Access Journals (Sweden)
Stephane eGrade
2015-06-01
Full Text Available The perception of reachability (i.e., whether an object is within reach relies on body representations and action simulation. Similarly, egocentric distance estimation (i.e., the perception of the distance an object is from the self is thought to be partly derived from embodied action simulation. Although motor simulation is important for both, it is unclear whether the cognitive processes underlying these behaviors rely on the same motor processes. To investigate this, we measured the impact of a motor interference dual-task paradigm on reachability judgment, egocentric distance estimation, and allocentric length estimation (i.e., how distant two stimuli are from each other independent from the self used as a control task. Participants were required to make concurrent actions with either hand actions of foam ball grip squeezing or arm actions of weight lifting, or no concurrent actions. Results showed that concurrent squeeze actions significantly slowed response speed in the reachability judgment and egocentric distance estimation tasks, but that there was no impact of the concurrent actions on allocentric length estimation. Together, these results suggest that reachability and distance perception, both egocentric perspective tasks, and in contrast to the allocentric perspective task, involve action simulation cognitive processes. The results are discussed in terms of the implication of action simulation when evaluating the position of a target relative to the observer’s body, supporting an embodied view of spatial cognition.
Zhang, Yi-Qing; Cui, Jing; Zhang, Shu-Min; Zhang, Qi; Li, Xiang
2016-02-01
Modelling temporal networks of human face-to-face contacts is vital both for understanding the spread of airborne pathogens and word-of-mouth spreading of information. Although many efforts have been devoted to model these temporal networks, there are still two important social features, public activity and individual reachability, have been ignored in these models. Here we present a simple model that captures these two features and other typical properties of empirical face-to-face contact networks. The model describes agents which are characterized by an attractiveness to slow down the motion of nearby people, have event-triggered active probability and perform an activity-dependent biased random walk in a square box with periodic boundary. The model quantitatively reproduces two empirical temporal networks of human face-to-face contacts which are testified by their network properties and the epidemic spread dynamics on them.
An Abstract Reachability Approach by Combining HOL Induction and Multiway Decision Graphs
Institute of Scientific and Technical Information of China (English)
Sa'ed Abed; Otmanc Ait Mohamed; Ghiath Al-Sammane
2009-01-01
In this paper, we provide a necessary infrastructure to define an abstract state exploration in the HOL theorem prover. Our infrastructure is based on a deep embedding of the Multiway Decision Graphs (MDGs) theory in HOL. MDGs generalize Reduced Ordered Binary Decision Diagrams (ROBDDs) to represent and manipulate a subset of first-order logic formulae. The MDGs embedding is based on the logical formulation of an MDG as Directed Formulae (DF). Then, the MDGs operations are defined and the correctness proof of each operation is provided. The MDG reachability algorithm is then defined as a conversion that uses our MDG theory within HOL. Finally, a set of experimentations over benchmark circuits has been conducted to ensure the applicability and to measure the performance of our approach.
Towards Symbolic Model-Based Mutation Testing: Combining Reachability and Refinement Checking
Aichernig, Bernhard K; 10.4204/EPTCS.80.7
2012-01-01
Model-based mutation testing uses altered test models to derive test cases that are able to reveal whether a modelled fault has been implemented. This requires conformance checking between the original and the mutated model. This paper presents an approach for symbolic conformance checking of action systems, which are well-suited to specify reactive systems. We also consider nondeterminism in our models. Hence, we do not check for equivalence, but for refinement. We encode the transition relation as well as the conformance relation as a constraint satisfaction problem and use a constraint solver in our reachability and refinement checking algorithms. Explicit conformance checking techniques often face state space explosion. First experimental evaluations show that our approach has potential to outperform explicit conformance checkers.
Reachable Distance Space: Efficient Sampling-Based Planning for Spatially Constrained Systems
Xinyu Tang,
2010-01-25
Motion planning for spatially constrained robots is difficult due to additional constraints placed on the robot, such as closure constraints for closed chains or requirements on end-effector placement for articulated linkages. It is usually computationally too expensive to apply sampling-based planners to these problems since it is difficult to generate valid configurations. We overcome this challenge by redefining the robot\\'s degrees of freedom and constraints into a new set of parameters, called reachable distance space (RD-space), in which all configurations lie in the set of constraint-satisfying subspaces. This enables us to directly sample the constrained subspaces with complexity linear in the number of the robot\\'s degrees of freedom. In addition to supporting efficient sampling of configurations, we show that the RD-space formulation naturally supports planning and, in particular, we design a local planner suitable for use by sampling-based planners. We demonstrate the effectiveness and efficiency of our approach for several systems including closed chain planning with multiple loops, restricted end-effector sampling, and on-line planning for drawing/sculpting. We can sample single-loop closed chain systems with 1,000 links in time comparable to open chain sampling, and we can generate samples for 1,000-link multi-loop systems of varying topologies in less than a second. © 2010 The Author(s).
Chen, Yi-Ting; Horng, Mong-Fong; Lo, Chih-Cheng; Chu, Shu-Chuan; Pan, Jeng-Shyang; Liao, Bin-Yih
2013-03-20
Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments.
Directory of Open Access Journals (Sweden)
Bin-Yih Liao
2013-03-01
Full Text Available Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments.
Calafiura, Paolo; Leggett, Charles; Seuster, Rolf; Tsulaia, Vakhtang; Van Gemmeren, Peter
2015-12-01
AthenaMP is a multi-process version of the ATLAS reconstruction, simulation and data analysis framework Athena. By leveraging Linux fork and copy-on-write mechanisms, it allows for sharing of memory pages between event processors running on the same compute node with little to no change in the application code. Originally targeted to optimize the memory footprint of reconstruction jobs, AthenaMP has demonstrated that it can reduce the memory usage of certain configurations of ATLAS production jobs by a factor of 2. AthenaMP has also evolved to become the parallel event-processing core of the recently developed ATLAS infrastructure for fine-grained event processing (Event Service) which allows the running of AthenaMP inside massively parallel distributed applications on hundreds of compute nodes simultaneously. We present the architecture of AthenaMP, various strategies implemented by AthenaMP for scheduling workload to worker processes (for example: Shared Event Queue and Shared Distributor of Event Tokens) and the usage of AthenaMP in the diversity of ATLAS event processing workloads on various computing resources: Grid, opportunistic resources and HPC.
Calafiura, Paolo; The ATLAS collaboration; Seuster, Rolf; Tsulaia, Vakhtang; van Gemmeren, Peter
2015-01-01
AthenaMP is a multi-process version of the ATLAS reconstruction and data analysis framework Athena. By leveraging Linux fork and copy-on-write, it allows the sharing of memory pages between event processors running on the same compute node with little to no change in the application code. Originally targeted to optimize the memory footprint of reconstruction jobs, AthenaMP has demonstrated that it can reduce the memory usage of certain confugurations of ATLAS production jobs by a factor of 2. AthenaMP has also evolved to become the parallel event-processing core of the recently developed ATLAS infrastructure for fine-grained event processing (Event Service) which allows to run AthenaMP inside massively parallel distributed applications on hundreds of compute nodes simultaneously. We present the architecture of AthenaMP, various strategies implemented by AthenaMP for scheduling workload to worker processes (for example: Shared Event Queue and Shared Distributor of Event Tokens) and the usage of AthenaMP in the...
Calafiura, Paolo; Seuster, Rolf; Tsulaia, Vakhtang; van Gemmeren, Peter
2015-01-01
AthenaMP is a multi-process version of the ATLAS reconstruction, simulation and data analysis framework Athena. By leveraging Linux fork and copy-on-write, it allows for sharing of memory pages between event processors running on the same compute node with little to no change in the application code. Originally targeted to optimize the memory footprint of reconstruction jobs, AthenaMP has demonstrated that it can reduce the memory usage of certain configurations of ATLAS production jobs by a factor of 2. AthenaMP has also evolved to become the parallel event-processing core of the recently developed ATLAS infrastructure for fine-grained event processing (Event Service) which allows to run AthenaMP inside massively parallel distributed applications on hundreds of compute nodes simultaneously. We present the architecture of AthenaMP, various strategies implemented by AthenaMP for scheduling workload to worker processes (for example: Shared Event Queue and Shared Distributor of Event Tokens) and the usage of Ath...
Energy Technology Data Exchange (ETDEWEB)
Greenberg, B.M.; Gurska, J.; Huang, X.D.; Gerhardt, K.E.; Yu, X.M.; Nykamp, J.; MacNeill, G.; Yang, S.; Lu, X.; Glick, B. [Waterloo Univ., ON (Canada). Dept. of Biology]|[Waterloo Environmental Biotechnology Inc., Hamilton, ON (Canada); Wang, W.; Knezevich, N. [Waterloo Univ., ON (Canada). Dept. of Biology; Gerwing, P.; Cryer, K. [Earthmaster Environmental Strategies Inc., Calgary, AB (Canada); Reid, N. [EBA Engineering Consultants Ltd., Edmonton, AB (Canada)
2008-07-01
The multi-process phytoremediation system (MPPS) was developed to degrade petroleum hydrocarbons (PHCs) in impacted soils. Phytoremediation of persistent contaminants in soils holds significant promise for rapid remediation kinetics. MPPS effectively removes polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPHs) and chlorinated hydrocarbons (CHCs) from soils. A plant growth promoting rhizobacteria interaction is the main element for success as it mitigates stress ethylene effects in plants, leading to high root biomass which, in turn, promotes growth of rhizosphere organisms. Field tests of the MPPS were initiated at a farm site in Sarnia, Ontario in the summer of 2004. The field was contaminated with petroleum hydrocarbons from refinery oil sludge. The second field trial was performed for 3 consecutive years at a petroleum contaminated biopile in Turner Valley, Alberta. The paper presented the results of the successful field tests of the MPPS. It was concluded that increased root biomass is achieved in the contaminated soils, which leads to more efficient and complete removal of TPHs in the field. Three years of field trials of the MPPS showed that remediation continues with successive seasons. 28 refs., 1 tab., 3 figs.
Energy Technology Data Exchange (ETDEWEB)
Greenberg, B.M.; Huang, X.D.; Gurska, Y.; Gerhardt, K.E.; Wang, W.; Lampi, M.A.; Zhang, C.; Khalid, A.; Isherwood, D.; Chang, P.; Wang, H.; Dixon, D.G.; Glick, B.R. [Waterloo Univ., ON (Canada)
2006-07-01
A large number of aquatic and terrestrial environments are polluted with various levels of toxicants. Metals, organics and total petroleum hydrocarbons from anthropogenic sources pose a risk to both human health and the health of ecosystems. Although these persistent contaminants are difficult to remediate, several industrial sites throughout North America are being remediated as part of land reclamation and restoration programs. This paper addressed the issue of phytoremediation for removing contaminants from soils. Phytoremediation is considered to be a viable remediation strategy because the increased biomass of plants, relative to the biomass of soil microbes in the absence of plants, allows for higher throughput. Extensive root systems can infiltrate large volumes of soil, thus promoting degradation of contaminants over a wide area. This paper described a newly developed multi-process phytoremediation system with accelerated remediation kinetics to effectively remove polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH) and chlorinated hydrocarbons (CHC) from soils. The system combines land farming/sunlight exposure; inoculation of contaminant degrading bacteria; and, plant growth with plant growth promoting rhizobacteria which mitigates the effects of stress ethylene in plants. The primary factor for success was the interaction between the plant and the plant growth promoting rhizobacteria. Several field tests were conducted following successful greenhouse tests. Results at a TPH contaminated site in Sarnia, Ontario showed that over a 2 year period, 60 to 70 per cent remediation of 15 per cent TPH was achieved. At a site in Turner Valley, Alberta, 35 per cent remediation of 1 per cent recalcitrant TPH was achieved, while a DDT contaminated site near Simcoe, Ontario had nearly 30 per cent of CHC removed in a 3 month period. 34 refs., 2 tabs., 2 figs.
Cowie, B. R.; Greenberg, B. M.; Slater, G. F.
2008-12-01
Optimizing remediation of petroleum-contaminated soils requires thorough understanding of the mechanisms and pathways involved in a proposed remediation system. In many engineered and natural attenuation systems, multiple degradation pathways may contribute to observed contaminant mass losses. In this study, biodegradation in the soil microbial community was identified as a major pathway for petroleum hydrocarbon removal in a Multi-Process Phytoremediation System (MPPS) using natural abundance 14C analysis of Phospholipid Fatty Acids (PLFA). In contaminated soils, PLFA were depleted in Δ14C to less than -800‰, directly demonstrating microbial uptake and utilization of petroleum derived carbon (Δ14C = -992‰) during bioremediation. Mass balance indicated that more than 80% of microbial carbon was derived from petroleum hydrocarbons and a maximum of 20% was produced from metabolism of modern carbon sources. In contrast, in a nearby uncontaminated control soil, the microbial community maintained a nearly modern 14C signature, suggesting preferential degradation of more labile, recent carbon. Mass balance using δ13C and Δ14C of soil CO2 demonstrated that mineralization of petroleum carbon contributed 60-65% of soil CO2 at the contaminated site. The remainder was derived from atmospheric (27-30%) and decomposition of non- petroleum natural organic carbon (5-10%). The clean control exhibited substantially lower CO2 concentrations that were derived from atmospheric (55%) and natural organic carbon (45%) sources. This study highlights the value of using multiple carbon isotopes to identify degradation pathways in petroleum- contaminated soils undergoing phytoremediation and the power of natural abundance 14C to detect petroleum metabolism in natural microbial communities.
Indian Academy of Sciences (India)
Ram Lal Awasthi
2016-02-01
The grand unification theories based on SO(10) gauge group have been at the centre of attraction to beyond Standard Model phenomenology. The SO(10) gauge symmetry may pass through several intermediate symmetries before breaking to Standard Model. Therefore some higher symmetries may occur at the experimentally reachable scales. This feature flourishes easily in non-supersymmetric models compared to supersymmetric ones. We find that certain breaking chains give tremendous predictions for the physics being explored at various particle physics experiments. Explanation to neutrino masses through TeV scale inverse see-saw is the driving theme of the models studied.
User-interfaces for hybrid systems: Analysis and design through hybrid reachability
Oishi, Meeko Mitsuko Karen
Hybrid systems combine discrete state dynamics, which model mode switching, with continuous state dynamics, which model the physical processes themselves. Applications of hybrid system theory to automated systems have traditionally assumed that the controller itself is an automaton which runs in parallel with the system under control. We model human interaction with hybrid systems, which involves the user; the automation's discrete mode-logic, and the underlying continuous dynamics of the physical system. Often in safety-critical systems, user-interfaces display a reduced set of information about the entire system, however must still provide adequate information and must not confuse the user. We present (1) a method of designing a discrete event system abstraction of the hybrid system, in order to verify or design user-interfaces for hybrid human-automation systems, and (2) the relationship between user-interfaces and discrete observability properties. Using a hybrid computational tool for reachability, we find the largest region in which the system can always remain---this is the safe region of operation. By implementing a controller which arises from this computation, we mathematically guarantee that this safe region is invariant. Assigning discrete states to the computed invariant regions, we create a discrete event system from this hybrid system with safety restrictions. This abstraction can then be used in existing interface verification and design methods. A user-interface, modeled as a discrete system, must, not only be reduced (extraneous information has been eliminated), but also "immediately observable". We derive conditions for immediate observability, in which the current state can be constructed from the current output and last occurring event. Based on finite state machine state-reduction techniques, we synthesize an output for remote user-interfaces which fulfills this property. Aircraft are prime examples of complex, safety-critical systems. In
Directory of Open Access Journals (Sweden)
M. De la Sen
2007-01-01
Full Text Available This paper investigates the properties of reachability, observability, controllability, and constructibility of positive discrete-time linear time-invariant dynamic systems when the sampling instants are chosen aperiodically. Reachability and observability hold if and only if a relevant matrix defining each of those properties is monomial for the set of chosen sampling instants provided that the continuous-time system is positive. Controllability and constructibility hold globally only asymptotically under close conditions to the above ones guaranteeing reachability/observability provided that the matrix of dynamics of the continuous-time system, required to be a Metzler matrix for the system's positivity, is furthermore a stability matrix while they hold in finite time only for regions excluding the zero vector of the first orthant of the state space or output space, respectively. Some related properties can be deduced for continuous-time systems and for piecewise constant discrete-time ones from the above general framework.
Ghorbani, Nima; Watson, P J; Farhadi, Mehran; Chen, Zhuo
2014-04-01
Self-regulation presumably rests upon multiple processes that include an awareness of ongoing self-experience, enduring self-knowledge and self-control. The present investigation tested this multi-process model using the Five-Facet Mindfulness Questionnaire (FFMQ) and the Integrative Self-Knowledge and Brief Self-Control Scales. Using a sample of 1162 Iranian university students, we confirmed the five-factor structure of the FFMQ in Iran and documented its factorial invariance across males and females. Self-regulatory variables correlated negatively with Perceived Stress, Depression, and Anxiety and positively with Self-Esteem and Satisfaction with Life. Partial mediation effects confirmed that self-regulatory measures ameliorated the disturbing effects of Perceived Stress. Integrative Self-Knowledge and Self-Control interacted to partially mediate the association of Perceived Stress with lower levels of Satisfaction with Life. Integrative Self-Knowledge, alone or in interaction with Self-Control, was the only self-regulation variable to display the expected mediation of Perceived Stress associations with all other measures. Self-Control failed to be implicated in self-regulation only in the mediation of Anxiety. These data confirmed the need to further examine this multi-process model of self-regulation. © 2014 International Union of Psychological Science.
Automating the multiprocessing environment
Energy Technology Data Exchange (ETDEWEB)
Arpasi, D.J.
1989-03-01
An approach to automate the programming and operation of tree-structured networks of multiprocessor systems is discussed. A conceptual, knowledge-based operating environment is presented, and requirements for two major technology elements are identified as follows: (1) An intelligent information translator is proposed for implementating information transfer between dissimilar hardware and software, thereby enabling independent and modular development of future systems and promoting a language-independence of codes and information; (2) A resident system activity manager, which recognizes the systems capabilities and monitors the status of all systems within the environment, is proposed for integrating dissimilar systems into effective parallel processing resources to optimally meet user needs. Finally, key computational capabilities which must be provided before the environment can be realized are identified.
Comparison and Analysis of Hash Algorithm for Multi-process Load Balancing%面向多进程负载均衡的Hash算法比较与分析
Institute of Scientific and Technical Information of China (English)
张莹; 吴和生
2014-01-01
Hash算法在高性能多进程负载均衡中起到关键作用，但目前面向多进程负载均衡的Hash算法研究主要集中在Hash算法设计和领域应用方面，较少有文献对现有的Hash算法性能进行分析比较。为此，总结面向多进程负载均衡的Hash算法应具有的特征，并据此筛选出5种适用于多进程负载均衡的主流Hash算法，从分配均衡性和耗时等方面进行理论分析和实验评估，为多进程负载均衡中Hash算法的选择与使用提供依据。分析结果表明， Toeplitz Hash算法较适合用于多进程的负载均衡。%Hash algorithm plays a key role in high performance multi-process load balancing. The study of Hash algorithm for multi-process load balancing is mainly concentrated on the design and application of Hash algorithm,yet analysis and comparative study for the performance of the existing Hash algorithm are fewer. So this paper summarizes the common features that Hash algorithm for multi-process load balancing should have, and screens five major Hash algorithms applied in multi-process load balancing. Theoretical analysis and experimental evaluation about balanced allocation and time-consuming of Hash algorithm provides a foundation for selecting Hash algorithm for multi-process load balancing,and shows that Toeplitz Hash is the best one.
Energy Technology Data Exchange (ETDEWEB)
Greenberg, B.M.; Huang, X.-D.; Gurska, Y.; Gerhardt, K.E.; Lampi, M.A.; Khalid, A.; Isherwood, D.; Chang, P.; Wang, W.; Wang, H.; Dixon, D.G.; Glick, B.R. [Waterloo Univ., ON (Canada). Dept. of Biology
2006-07-01
If efficient systems with rapid remediation kinetics can be realized, phytoremediation of persistent contaminants from soils holds great promise. A multi-process phytoremediation system (MPPS) with accelerated remediation kinetics that effectively removes polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPHs) and chlorinated hydrocarbons (CHCs) from soils has been developed. A plant growth promoting rhizobacteria interaction is the main element for success as it mitigates stress ethylene effects in plants, leading to high root biomass which, in turn, promotes growth of rhizosphere organisms. Based on the success of greenhouse experiments, field tests of the MPPS were initiated at an Imperial Oil land farm site in Sarnia, Ontario in the summer of 2004, followed by 127 field tests at the same site in the summer of 2005 and 2006. In addition, a total petroleum hydrocarbons (TPH) contaminated site in Alberta was used in 2005 and 2006. The study presented and discussed selected results of successful greenhouse, pilot field tests and field tests of the MPPS. It was concluded that increased root biomass is achieved in the contaminated soils, which leads to more efficient and complete removal of TPHs in the field. Three years of field trials of the MPPS showed that remediation continues with successive seasons. 27 refs., 2 tabs., 1 fig.
Linux based multi-process MDSL study and design%基于Linux的多进程MDSL研究与设计
Institute of Scientific and Technical Information of China (English)
何宏宇; 刘正熙; 陈正茂
2013-01-01
针对Windows下MDSL(多通道同步数字记录仪)系统耦合度高,稳定性和实时性不够理想的缺陷,本文提出了新的系统架构和设计.该设计基于Linux操作系统(2.6内核),采用了多进程方式降低系统耦合度,提高系统可靠性,并采用双机冗余和守护进程等设计保证系统稳定性,同时采用了多线程管理方式实现远程控制单元.实践表明,新系统拥有更好的可靠性以及可维护性.%Since Windows based MDSL system has defects like high coupling, relatively not stable and weak real-time, this paper puts forward a new system structure and design. Based on the Linux operating system (2. 6 kernel) ,this design uses a multiprocessing mode to reduce the system coupling, improve the system reliability, and ensure the stability of the system by using designs like dual machine redundancy and daemon process, and using the multi-threaded mode to process command so as to realize the remote control unit. The practice shows that the new system has better reliability and maintainability than the old one.
The Study of Reachable Range for Urban Pedestrian System on Early Peak%城市早高峰步行可达范围研究
Institute of Scientific and Technical Information of China (English)
郑柯; 吴玮
2013-01-01
根据步行与其他交通方式对比的优势距离及对城市早高峰居民步行出行实际调查数据,研究城市步行出行的可达范围.%This paper studies the actual survey data of urban residents'travelling by walking, bus and bicycle. It analyses the travel time and route on foot comparing with bus and bicycle. According to the study it puts forward the relationship of urban tarvel time among walking, bus and bicycle. Then it i-dentifies the reachable range of urban travel by walking on early peak. All these research findings provide the theory reference for transportation planning of urban pedestrian system.
Multiprocessing the Sieve of Eratosthenes
Bokhari, S.
1986-01-01
The Sieve of Eratosthenes for finding prime numbers in recent years has seen much use as a benchmark algorithm for serial computers while its intrinsically parallel nature has gone largely unnoticed. The implementation of a parallel version of this algorithm for a real parallel computer, the Flex/32, is described and its performance discussed. It is shown that the algorithm is sensitive to several fundamental performance parameters of parallel machines, such as spawning time, signaling time, memory access, and overhead of process switching. Because of the nature of the algorithm, it is impossible to get any speedup beyond 4 or 5 processors unless some form of dynamic load balancing is employed. We describe the performance of our algorithm with and without load balancing and compare it with theoretical lower bounds and simulated results. It is straightforward to understand this algorithm and to check the final results. However, its efficient implementation on a real parallel machine requires thoughtful design, especially if dynamic load balancing is desired. The fundamental operations required by the algorithm are very simple: this means that the slightest overhead appears prominently in performance data. The Sieve thus serves not only as a very severe test of the capabilities of a parallel processor but is also an interesting challenge for the programmer.
Scalable shared-memory multiprocessing
Lenoski, Daniel E
1995-01-01
Dr. Lenoski and Dr. Weber have experience with leading-edge research and practical issues involved in implementing large-scale parallel systems. They were key contributors to the architecture and design of the DASH multiprocessor. Currently, they are involved with commercializing scalable shared-memory technology.
BACH: A Toolset for Bounded Reachability Analysis of Linear Hybrid Systems%BACH:线性混成系统有界可达性模型检验工具
Institute of Scientific and Technical Information of China (English)
卜磊; 李游; 王林章; 李宣东
2011-01-01
混成自动机的模型检验问题非常困难,即使是其中相对简单的一个子类--线性混成自动机,它的可达性问题仍然是不可判定的.现有的相关工具大都使用多面体计算来判定线性混成自动机状态空间的可达集,复杂度高、效率低,无法解决实际应用规模的问题.描述了一个面向线性混成系统有界可达性模型检验工具--BACH(bounded reachability checker),该工具能够沿指定路径(组)对单个线性混成自动机、多个线性混成自动机的组合进行可达性检验,并且在此基础上结合路径遍历技术完成对所有路径的有界可达性检验.实验数据显示,BACH不仅在面向路径可达性检验方面性能优异,可以适用于足够长度的路径,而且在针对所有路径的有界可达性检验时,BACH可以解决的问题规模也远远超过同类工具,已接近工业界应用的要求.%The model-checking problem for hybrid systems is very difficult to resolve.Even for a relatively simple class of hybrid systems, the class of linear hybrid automata, the most common problem of reachability is unsolvable.Existing techniques for the reachability analysis of linear hybrid automata do not scale well to problem sizes of practical interest.Instead of developing a tool to perform a reachability checking of the complete state space of linear hybrid automata, a prototype toolset BACH (bounded reachability checker) is presented to perform path-oriented reachability checking and bounded reachability checking of the linear hybrid automata and the compositional linear hybrid systems, where the length of the path being checked can be made very large, and the size of the system can be made large enough to handle problems of practical interest.The experiment data shows that BACH has good performance and scalability and supports the fact that BACH can become a powerful assistant for design engineers in the reachability analysis of linear hybrid automata.
Taming Past LTL and Flat Counter Systems
Demri, Stéphane; sangnier, Arnaud
2012-01-01
Reachability and LTL model-checking problems for flat counter systems are known to be decidable but whereas the reachability problem can be shown in NP, the best known complexity upper bound for the latter problem is made of a tower of several exponentials. Herein, we show that the problem is only NP-complete even if LTL admits past-time operators and arithmetical constraints on counters. Actually, the NP upper bound is shown by adequately combining a new stuttering theorem for Past LTL and the property of small integer solutions for quantifier-free Presburger formulae. Other complexity results are proved, for instance for restricted classes of flat counter systems.
The Reachability Analysis About Zero Discharge of Wastewater in Xiaoqing Mine%小青煤矿废水零排放可达性分析
Institute of Scientific and Technical Information of China (English)
王浩
2013-01-01
煤炭开采在对地方经济做出重大贡献的同时，也对当地的环境质量造成一定破坏。小青煤矿附近区河流流量较小，冬季结冰，水体自净能力较差，其工业广场污废水排入河流后，导致河流水质经常超标。为了从根本上解决地表水污染问题，该矿在洗煤废水闭路循环的基础上提出实现全部废水的零排放，以切断对地表水的污染途径。通过分析该矿废水排放环节及废水治理措施，得出废水零排放的可达性，在煤炭企业中具有一定的推广意义。%Coal mining in the same time to make a significant contribution to the local economy,but also on the quality of the local environment,causing some damage. Small the Xiaoqing coal mine near area rivers flow,winter icing and poor self-purification capacity of the water,the Industrial Plaza sewage and waste into the river, the river water quality is often excessive. In order to fundamentally solve the problem of surface water pollution,mine is proposed on the basis of the coal washing wastewater closed loop wastewater zero emissions,to cut pollution of surface water pathways. Draw the reachability of zero discharge of wastewater through the analysis of the the mine wastewater emissions links and wastewater treatment measures,promotion of coal enterprises have certain significance.
Reachability Analysis of Probabilistic Systems
DEFF Research Database (Denmark)
D'Argenio, P. R.; Jeanett, B.; Jensen, Henrik Ejersbo
2001-01-01
than the original model, and may safely refute or accept the required property. Otherwise, the abstraction is refined and the process repeated. As the numerical analysis involved in settling the validity of the property is more costly than the refinement process, the method profits from applying...... such numerical analysis on smaller state spaces. The method is significantly enhanced by a number of novel strategies: a strategy for reducing the size of the numerical problems to be analyzed by identification of so-called {essential states}, and heuristic strategies for guiding the refinement process....
Eternal Domination: Criticality and Reachability
Directory of Open Access Journals (Sweden)
Klostermeyer William F.
2017-02-01
Full Text Available We show that for every minimum eternal dominating set, D, of a graph G and every vertex v ∈ D, there is a sequence of attacks at the vertices of G which can be defended in such a way that an eternal dominating set not containing v is reached. The study of the stronger assertion that such a set can be reached after a single attack is defended leads to the study of graphs which are critical in the sense that deleting any vertex reduces the eternal domination number. Examples of these graphs and tight bounds on connectivity, edge-connectivity and diameter are given. It is also shown that there exist graphs in which deletion of any edge increases the eternal domination number, and graphs in which addition of any edge decreases the eternal domination number.
Walking Reachability Of Urban Public Space：Nangang District, Harbin%城市公共空间步行可达性发展对策--以哈尔滨市南岗区为例
Institute of Scientific and Technical Information of China (English)
卫大可; 杨秋楠
2016-01-01
Public space is important for citizen outdoor iftness activities, and walking reachability is crucial to the utilization of public space. With Nangang district, Harbin case, this article conducts a survey on various urban public space for iftness activities, analyzes the factors that inlfuence walking reachability, and proposes relevant development strategies.%城市公共空间是市民开展经常性户外健身活动的重要场所，而步行可达性是决定城市公共空间在多大程度上为市民健身活动利用的关键因素。文章力求以点带面，以哈尔滨市南岗区为案例进行研究，通过对各类城市公共空间的全民健身使用情况进行调查，分析以市民健身活动为目的的城市公共空间步行可达性的影响因素，提出面向全民健身需求的城市公共空间步行可达性发展对策。
DEFF Research Database (Denmark)
Dung, Phan Anh; Hansen, Michael Reichhardt
2015-01-01
platform executing on an 8-core machine. A speedup of approximately 4 was obtained for Cooper’s algorithm and a speedup of approximately 6 was obtained for the exact-shadow part of the Omega Test. The considered procedures are complex, memory-intense algorithms on huge formula trees and the case study...... reveals more general applicable techniques and guideline for deriving parallel algorithms from sequential ones in the context of data-intensive tree algorithms. The obtained insights should apply for any strict and impure functional programming language. Furthermore, the results obtained for the exact......-shadow elimination procedure have a wider applicability because they can directly be transferred to the Fourier–Motzkinelimination method....
On Tool Support for Duration Calculus on the Basis of Presburger Arithmetic
DEFF Research Database (Denmark)
Hansen, Michael Reichhardt; Brekling, Aske Wiid
2011-01-01
Interval Logics are often very expressive logics for which decision and model-checking algorithms are hard or even impossible to achieve, and this also applies for Duration Calculus, which adds the notion of accumulated duration to the Interval Temporal Logic introduced by Moszkowski et al. In th...
自动气象站资料动态多进程处理模型的设计与应用%Design and Application of Dynamic Multi-Process Model for AWS Data Processing
Institute of Scientific and Technical Information of China (English)
刘媛媛; 琚玲; 何文春
2012-01-01
针对目前气象预报及资料同化等业务对数据服务时效的需求，设计给出一种动态多进程的调度模型。该模型根据配置文件确定进程处理自动站资料的范围，同时采用带参数进程对重点区域进行处理。应用结果表明，动态多进程调度模型能够简单方便地根据应急保障需求调整自动站资料的处理策略，以保障具有最高时效要求的资料的处理性能。通过在应对甘肃舟曲泥石流灾害等三次应用证明能使资料处理时效提高80％左右。%Because large quantities of automatic weather station (AWS) data are increasing dramatically as well as the weather forecast system and data assimilation system are developing continually, the current processing efficiency of AWS data is unable to meet the requirement of data users. Aimed at efficiency problem of AWS data, a dynamic multi-process data processing model is proposed. In this model, configu- ration flies are used to define handling scope of each process, and a process with parameter is designed to deal with the data of particular region which needs to be got efficiently. The model has been implemented in three cases such as disastrous debris flow at Zhouqu, Gansu Province on 7 August 2010. The result shows that data processing strategy can be adjusted easily in terms of important weather phenomena and data processing timeliness can be guaranteed, increasing data processing efficiency by 80%.
Multiprocessing on supercomputers for computational aerodynamics
Yarrow, Maurice; Mehta, Unmeel B.
1991-01-01
Little use is made of multiple processors available on current supercomputers (computers with a theoretical peak performance capability equal to 100 MFLOPS or more) to improve turnaround time in computational aerodynamics. The productivity of a computer user is directly related to this turnaround time. In a time-sharing environment, such improvement in this speed is achieved when multiple processors are used efficiently to execute an algorithm. The concept of multiple instructions and multiple data (MIMD) is applied through multitasking via a strategy that requires relatively minor modifications to an existing code for a single processor. This approach maps the available memory to multiple processors, exploiting the C-Fortran-Unix interface. The existing code is mapped without the need for developing a new algorithm. The procedure for building a code utilizing this approach is automated with the Unix stream editor.
Adaptive runtime for a multiprocessing API
Energy Technology Data Exchange (ETDEWEB)
Antao, Samuel F.; Bertolli, Carlo; Eichenberger, Alexandre E.; O' Brien, John K.
2016-10-11
A computer-implemented method includes selecting a runtime for executing a program. The runtime includes a first combination of feature implementations, where each feature implementation implements a feature of an application programming interface (API). Execution of the program is monitored, and the execution uses the runtime. Monitor data is generated based on the monitoring. A second combination of feature implementations are selected, by a computer processor, where the selection is based at least in part on the monitor data. The runtime is modified by activating the second combination of feature implementations to replace the first combination of feature implementations.
Adaptive runtime for a multiprocessing API
Energy Technology Data Exchange (ETDEWEB)
Antao, Samuel F.; Bertolli, Carlo; Eichenberger, Alexandre E.; O' Brien, John K.
2016-11-15
A computer-implemented method includes selecting a runtime for executing a program. The runtime includes a first combination of feature implementations, where each feature implementation implements a feature of an application programming interface (API). Execution of the program is monitored, and the execution uses the runtime. Monitor data is generated based on the monitoring. A second combination of feature implementations are selected, by a computer processor, where the selection is based at least in part on the monitor data. The runtime is modified by activating the second combination of feature implementations to replace the first combination of feature implementations.
Institute of Scientific and Technical Information of China (English)
陈波
2011-01-01
组合服务的接口交互行为的分析和检测是服务计算领域的一个重要课题。本文以接口自动机为组合服务接口模型,引入组合环境的因素,提出了在给定的组合环境下服务接口交互强弱相容性的概念,并给出了相容性判定的判据表达式。通过遍历组合服务接口模型进行可达性分析,并通过检测判据表达式是否满足来判定服务接口交互的相容性,同时实现了服务与环境交互相容性的判定。%Analysis and verification of composite services interacting with an interface is an important issue in service computing.The interface automata are taken as the model of composite services interacting in this paper.By introducing an environment factor into analysis,the concept of strong and weak compatibility of service interacting under specific environment is proposed,and the expression of criterion for compatibility checking is presented.In order to check the compatibility of service interfaces,the interacting model of composite services is traversed with the reachable analysis,and the compatibility of service with environment has been checked.
Reachability computation for hybrid systems with Ariadne
L. Benvenuti; D. Bresolin; A. Casagrande; P.J. Collins (Pieter); A. Ferrari; E. Mazzi; T. Villa; A. Sangiovanni-Vincentelli
2008-01-01
htmlabstractAriadne is an in-progress open environment to design algorithms for computing with hybrid automata, that relies on a rigorous computable analysis theory to represent geometric objects, in order to achieve provable approximation bounds along the computations. In this paper we discuss the
Reachability Analysis Applied to Space Situational Awareness
2009-09-01
corresponding initial conditions xT0 = [d T 0 vT0 ] satisfying (5) are found by solving the following system of equations [19]: dfdf 0 = Mφz(tf ; x0...the corresponding initial direction magnitude d and velocity v0 satisfying (5) are found by solving the following equations: dfdf 0 = Mφz(tf
Delta-Complete Reachability Analysis (Part 1)
2013-12-01
Lecture Notes in Computer Science , pages...and G. Rozenberg, editors, REX Workshop, volume 600 of Lecture Notes in Computer Science , pages 45–73. Springer, 1991. [4] M. Fränzle. Analysis of...hybrid systems: An ounce of realism can save an infinity of states. In J. Flum and M. Rodrı́guez-Artalejo, editors, CSL, volume 1683 of Lecture Notes in Computer Science ,
Sparse Dataflow Analysis with Pointers and Reachability
DEFF Research Database (Denmark)
Madsen, Magnus; Møller, Anders
2014-01-01
quadtrees. The framework is presented as a systematic modification of a traditional dataflow analysis algorithm. Our experimental results demonstrate the effectiveness of the technique for a suite of JavaScript programs. By also comparing the performance with an idealized staged approach that computes...
Multiprocessing system for performing floating point arithmetic operations
Energy Technology Data Exchange (ETDEWEB)
Nguyenphu, M.; Thatcher, L.E.
1990-10-02
This patent describes a data processing system. It comprises: a fixed point arithmetic processor means for performing fixed point arithmetic operations and including control means for decoding a floating point arithmetic instruction specifying a floating point arithmetic operation, and an addressing means for computing addresses for floating point data for the floating point operation from a memory means. The memory means for storing data and including means for receiving the addresses from the fixed point arithmetic processor means and providing the floating point data to a floating point arithmetic processor means; and the floating point arithmetic processor means for performing floating point arithmetic operations and including control means for decoding the floating point instruction and performing the specified floating point arithmetic operation upon the floating point data from the memory means.
AMPL: Design, Implementation, and Evaluation of a Multiprocessing Language
1981-03-31
all those who designed and built CM’. 71 References [1] W. B. Ackerman. A structure processing facility for dato flow computers. In G. Jack Lipovski...Acta Informatica 1:35-63, 1971. 74 (37] N. Wirth. Modula: A programming language for modular multiprogramming. Software -Practice and Experience 7(l
Scheduling Temporal Partitions in a Multiprocessing Paradigm for Reconfigurable Architectures
DEFF Research Database (Denmark)
Popp, Andreas; Le Moullec, Yannick; Koch, Peter
2009-01-01
I rapporten er udviklet metoder og redskaber, som den kommunale planlægning kan benytte i håndteringen af demografi ske og kommunaløkonomiske udfordringer i fremtiden. Rapporten belyser, ved hjælp af spørgeskemaundersøgelse og fokusgruppeinterviews, tilflytterne til nybyggeri i Køge Kommune samt ...
Veridical and False Memory for Text: A Multiprocess Analysis
Singer, Murray; Remillard, Gilbert
2008-01-01
People report recognizing discourse inferences at rates that approach target acceptance. Brainerd et al. [Brainerd, C. J., Wright, R., Reyna, V. F., & Mojardin, A. H. (2001). "Conjoint recognition and phantom recollection." "Journal of Experimental Psychology: Learning, Memory, and Cognition, 27", 307-329] proposed that…
Evaluating choices in multi-process landscape evolution models
Temme, A.J.A.M.; Claessens, L.; Veldkamp, A.; Schoorl, J.M.
2011-01-01
The interest in landscape evolution models (LEMs) that simulate multiple landscape processes is growing. However, modelling multiple processes constitutes a new starting point for which some aspects of the set up of LEMs must be re-evaluated. The objective of this paper is to demonstrate the practic
Introduction of Virtualization Technology to Multi-Process Model Checking
Leungwattanakit, Watcharin; Artho, Cyrille; Hagiya, Masami; Tanabe, Yoshinori; Yamamoto, Mitsuharu
2009-01-01
Model checkers find failures in software by exploring every possible execution schedule. Java PathFinder (JPF), a Java model checker, has been extended recently to cover networked applications by caching data transferred in a communication channel. A target process is executed by JPF, whereas its peer process runs on a regular virtual machine outside. However, non-deterministic target programs may produce different output data in each schedule, causing the cache to restart the peer process to handle the different set of data. Virtualization tools could help us restore previous states of peers, eliminating peer restart. This paper proposes the application of virtualization technology to networked model checking, concentrating on JPF.
On the Scalability of Time-predictable Chip-Multiprocessing
DEFF Research Database (Denmark)
Puffitsch, Wolfgang; Schoeberl, Martin
2012-01-01
simple processors is not an option for embedded systems with high demands on computing power. In order to provide high performance and predictability we argue to use multiprocessor systems with a time-predictable memory interface. In this paper we present the scalability of a Java chip...
Institute of Scientific and Technical Information of China (English)
张涛; 刘晓华; 江亿
2011-01-01
A model is established to analyze the heat and moisture transfer process in air-water or-hydroscopic solution system, two independent driving forces each other: enthalpy difference and relative humidity difference can be obtained. A triangle region, consisting of iso-enthalpy line from air inlet, saturation line of moisture air (iso-concentration line of solution) and connecting line of air and water or solution at inlet status, is determined in enthalpy-psychrometric chart based on relationship between the two driving forces. The region is a reachable handling region for heat and moisture transfer process in air-water or-hydroscopic solution system, because the variation of air outlet status is limited in the region whatever change of mass and heat transfer coefficients or flow pattern and rate. Experimental results of dehumidification and regeneration in literatures are analyzed with the help of reachable handling region.%利用模型研究空气与水或吸湿溶液热湿传递过程的特性,得到两个相互独立的驱动力——焓差驱动力和相对湿度差驱动力.根据两驱动力的关系在焓湿图上确定了一个由空气进口等焓线、湿空气饱和线(或溶液等浓度线)、空气与水或溶液进口状态连线围成的三角形区域,不论流型、传热传质系数或流量如何变化,空气出口状态只能在该区域内变化,即为空气与水或吸湿溶液热湿传递过程的可及处理区域.应用可及处理区域分析了文献中除湿实验、再生实验的热湿处理结果,明确了实验装置所处的性能水平.
Monomial strategies for concurrent reachability games and other stochastic games
DEFF Research Database (Denmark)
Frederiksen, Søren Kristoffer Stiil; Miltersen, Peter Bro
2013-01-01
We consider two-player zero-sum finite (but infinite-horizon) stochastic games with limiting average payoffs. We define a family of stationary strategies for Player I parameterized by ε > 0 to be monomial, if for each state k and each action j of Player I in state k except possibly one action, we...
Delta-Complete Analysis for Bounded Reachability of Hybrid Systems
2014-07-16
can occur in realistic hybrid sys- tems, such as polynomials, trigonometric functions , and solutions of Lipschitz-continuous ODEs. The goal of this...systems are Type 2 computable, such as polynomials, exponentiation, logarithm, trigonometric functions , and solution functions of Lipschitz-continuous...comes from the need of solving logic formulas over the real numbers with nonlinear functions , which is notoriously hard. Recently, we have defined the δ
Spatio-Temporal Complex Networks: Reachability, Centrality, and Robustness
Williams, Matthew J
2015-01-01
While recent advances in spatial and temporal networks have enabled researchers to more-accurately describe many real-world systems, existing models do not capture the combined constraint that space and time impose on the relationships and interactions present in a spatio-temporal complex network. This has important consequences, often resulting in an over-simplification of the resilience of a system and obscuring the network's true structure. In this paper, we study the response of spatio-temporal complex networks to random error and systematic attack. Firstly, we propose a model of spatio-temporal paths in time-varying spatially embedded networks. This model captures the property that, in many real-world systems, interaction between nodes is non-instantaneous and governed by the space in which they are embedded. Secondly, using numerical experiments on four empirical examples of such systems, we study the effect of node failure on a network's topological, temporal, and spatial structure. We find that networ...
Reachability bounds for chemical reaction networks and strand displacement systems.
Condon, Anne; Kirkpatrick, Bonnie; Maňuch, Ján
2014-01-01
Chemical reaction networks (CRNs) and DNA strand displacement systems (DSDs) are widely-studied and useful models of molecular programming. However, in order for some DSDs in the literature to behave in an expected manner, the initial number of copies of some reagents is required to be fixed. In this paper we show that, when multiple copies of all initial molecules are present, general types of CRNs and DSDs fail to work correctly if the length of the shortest sequence of reactions needed to produce any given molecule exceeds a threshold that grows polynomially with attributes of the system.
Hybrid system for computing reachable workspaces for redundant manipulators
Alameldin, Tarek K.; Sobh, Tarek M.
1991-03-01
An efficient computation of 3D workspaces for redundant manipulators is based on a " hybrid" a!- gorithm between direct kinematics and screw theory. Direct kinematics enjoys low computational cost but needs edge detection algorithms when workspace boundaries are needed. Screw theory has exponential computational cost per workspace point but does not need edge detection. Screw theory allows computing workspace points in prespecified directions while direct kinematics does not. Applications of the algorithm are discussed.
Controllability, Observability, Reachability, and Stability of Dynamic Linear Systems
Jackson, Billy J; Gravagne, Ian A; Marks, Robert J
2009-01-01
We develop a linear systems theory that coincides with the existing theories for continuous and discrete dynamical systems, but that also extends to linear systems defined on nonuniform time domains. The approach here is based on generalized Laplace transform methods (e.g. shifts and convolution) from our recent work \\cite{DaGrJaMaRa}. We study controllability in terms of the controllability Gramian and various rank conditions (including Kalman's) in both the time invariant and time varying settings and compare the results. We also explore observability in terms of both Gramian and rank conditions as well as realizability results. We conclude by applying this systems theory to connect exponential and BIBO stability problems in this general setting. Numerous examples are included to show the utility of these results.
Module-theoretic properties of reachability modules for SRIQ
CSIR Research Space (South Africa)
Nortje, R
2013-07-01
Full Text Available this signature. A closely related notion to conservative extensions is that of inseparability. Definition 3. [13] T1 and T2 are Σ-concept name inseparable, written T1 ≡cΣ T2, if for all Σ- concept names C,D, it holds that T1 |= C v D if and only if T2 |= C v D.... Definition 4. [13] T1 and T2 are Σ-subsumption inseparable, written T1 ≡sΣ T2, if for all terms X,Y that are concepts or roles over Σ, it holds that T1 |= X v Y if and only if T2 |= X v Y . Definition 5. [13] Let T be a TBox, M⊆ T , S an inseparability...
Synthesis of railway-signaling plans using reachability games
DEFF Research Database (Denmark)
Kasting, Patrick Frederik Soelmark; Hansen, Michael Reichhardt; Vester, Steen
2016-01-01
In this work, we show the feasibility of using functional programming (more specifically F#) in connection with gamebased methods for synthesis of correct-by-construction controllers (also called signaling plans) for railway networks. This is a massively resource-demanding application. A model...... (the control system) controls signals and points and the universal player (the antagonistic environment) controls movement of trains. A winning strategy for the existential player provides a signaling plan that will safely guide trains through the network. The concepts from the railway network model...... that we are able to synthesize signaling plans for real railway networks of substantial size....
Are Religious Tolerance and Pluralism Reachable Ideals? A Psychological Perspective
van der Straten Waillet, Nastasya; Roskam, Isabelle
2013-01-01
The aim of this article is to consider the psychological mechanisms that may prevent individuals from achieving religious tolerance and religious pluralism. After defining these concepts and explaining why they are desirable outcomes, four psychological obstacles to the achievement of religious tolerance and religious pluralism will be explored by…
Reachability-based Analysis for Probabilistic Roadmap Planners
Geraerts, R.J.; Overmars, M.H.
2007-01-01
In the last fifteen years, sampling-based planners like the Probabilistic Roadmap Method (PRM) have proved to be successful in solving complex motion planning problems. While theoretically, the complexity of the motion planning problem is exponential in the number of degrees of freedom, sampling-bas
Reachability-based Analysis for Probabilistic Roadmap Planners
Geraerts, R.J.; Overmars, M.H.
2007-01-01
In the last fifteen years, sampling-based planners like the Probabilistic Roadmap Method (PRM) have proved to be successful in solving complex motion planning problems. While theoretically, the complexity of the motion planning problem is exponential in the number of degrees of freedom,
Methods for Reachability-based Hybrid Controller Design
2012-05-10
Markov Decision Processes (see for example Russell and Norvig , 2002; Thrun et al., 2005). Given a finite state space, the state transition kernel ν can be...distribution p0 and the information vector ik. The update equations for pk|k can be found in for example Chapter 17 of Russell and Norvig (2002) or...for POMDP problems to find the optimal control policy (Russell and Norvig , 2002, Chapter 17; Thrun et al., 2005, Chapter 15). However, as shown by
Development of a prototype multi-processing interactive software invocation system
Berman, W. J.
1983-01-01
The Interactive Software Invocation System (NASA-ISIS) was first transported to the M68000 microcomputer, and then rewritten in the programming language Path Pascal. Path Pascal is a significantly enhanced derivative of Pascal, allowing concurrent algorithms to be expressed using the simple and elegant concept of Path Expressions. The primary results of this contract was to verify the viability of Path Pascal as a system's development language. The NASA-ISIS implementation using Path Pascal is a prototype of a large, interactive system in Path Pascal. As such, it is an excellent demonstration of the feasibility of using Path Pascal to write even more extensive systems. It is hoped that future efforts will build upon this research and, ultimately, that a full Path Pascal/ISIS Operating System (PPIOS) might be developed.
A comprehensive, multi-process box-model approach to glacial-interglacial carbon cycling
Directory of Open Access Journals (Sweden)
A. M. de Boer
2010-05-01
Full Text Available The canonical question of which physical, chemical or biological mechanisms were responsible for oceanic uptake of atmospheric CO_{2} during the last glacial is yet unanswered. Insight from paleo proxies has led to a multitude of hypotheses but none so far have been convincingly supported in three dimensional numerical modelling experiments. The processes that influence the CO_{2} uptake and export production are inter-related and too complex to solve conceptually while complex numerical models are time consuming and expensive to run which severely limits the combinations of mechanisms that can be explored. Instead, an intermediate inverse box model approach is used here in which the whole parameter space is explored. The glacial circulation and biological production states are derived from these using proxies of glacial export production and the need to draw down CO_{2} into the ocean. We find that circulation patterns which explain glacial observations include reduced Antarctic Bottom Water formation and high latitude mixing and to a lesser extent reduced equatorial upwelling. The proposed mechanism of CO_{2} uptake by an increase of eddies in the Southern Ocean, leading to a reduced residual circulation, is not supported. Regarding biological mechanisms, an increase in the nutrient utilization in either the equatorial regions or the northern polar latitudes can reduce atmospheric CO_{2} and satisfy proxies of glacial export production. Consistent with previous studies, CO_{2} is drawn down more easily through increased productivity in the Antarctic region than the sub-Antarctic, but that violates observations of lower export production there.
Belmont, Patrick; Foufoula-Georgiou, Efi
2017-04-01
Changes in climate and agricultural practices are putting pressure on agroenvironmental systems all over the world. Predicting the effects of future management or conservation actions has proven exceptionally challenging in these complex landscapes. We present a perspective, gained from a decade of research and stakeholder involvement in the Minnesota River Basin, where research findings have influenced solutions and policy in directions not obvious at the outset. Our approach has focused on identifying places, times, and processes of accelerated change and developing reduced complexity predictive frameworks that can inform mitigation actions.
A survey on the design of multiprocessing systems for artificial intelligence applications
Wah, Benjamin W.; Li, Guo Jie
1989-01-01
Some issues in designing computers for artificial intelligence (AI) processing are discussed. These issues are divided into three levels: the representation level, the control level, and the processor level. The representation level deals with the knowledge and methods used to solve the problem and the means to represent it. The control level is concerned with the detection of dependencies and parallelism in the algorithmic and program representations of the problem, and with the synchronization and sheduling of concurrent tasks. The processor level addresses the hardware and architectural components needed to evaluate the algorithmic and program representations. Solutions for the problems of each level are illustrated by a number of representative systems. Design decisions in existing projects on AI computers are classed into top-down, bottom-up, and middle-out approaches.
An FPGA Based Multiprocessing CPU for Beam Synchronous Timing in CERN's SPS and LHC
Ballester, F J; Gras, J J; Lewis, J; Savioz, J J; Serrano, J
2003-01-01
The Beam Synchronous Timing system (BST) will be used around the LHC and its injector, the SPS, to broadcast timing meassages and synchronize actions with the beam in different receivers. To achieve beam synchronization, the BST Master card encodes messages using the bunch clock, with a nominal value of 40.079 MHz for the LHC. These messages are produced by a set of tasks every revolution period, which is every 89 us for the LHC and every 23 us for the SPS, therefore imposing a hard real-time constraint on the system. To achieve determinism, the BST Master uses a dedicated CPU inside its main Field Programmable Gate Array (FPGA) featuring zero-delay hardware task switching and a reduced instruction set. This paper describes the BST Master card, stressing the main FPGA design, as well as the associated software, including the LynxOS driver and the tailor-made assembler.
A Multi-Process Test Case to Perform Comparative Analysis of Coastal Oceanic Models
Lemarié, F.; Burchard, H.; Knut, K.; Debreu, L.
2016-12-01
Due to the wide variety of choices that need to be made during the development of dynamical kernels of oceanic models, there is a strong need for an effective and objective assessment of the various methods and approaches that predominate in the community. We present here an idealized multi-scale scenario for coastal ocean models combining estuarine, coastal and shelf sea scales at midlatitude. The bathymetry, initial conditions and external forcings are defined analytically so that any model developer or user could reproduce the test case with its own numerical code. Thermally stratified conditions are prescribed and a tidal forcing is imposed as a propagating coastal Kelvin wave. The following physical processes can be assessed from the model results: estuarine process driven by tides and buoyancy gradients, the river plume dynamics, tidal fronts, and the interaction between tides and inertial oscillations. We show results obtained using the GETM (General Estuarine Transport Model) and the CROCO (Coastal and Regional Ocean Community model) models. Those two models are representative of the diversity of numerical methods in use in coastal models: GETM is based on a quasi-lagrangian vertical coordinate, a coupled space-time approach for advective terms, a TVD (Total Variation Diminishing) tracer advection scheme while CROCO is discretized with a quasi-eulerian vertical coordinate, a method of lines is used for advective terms, and tracer advection satisfies the TVB (Total Variation Bounded) property. The multiple scales are properly resolved thanks to nesting strategies, 1-way nesting for GETM and 2-way nesting for CROCO. Such test case can be an interesting experiment to continue research in numerical approaches as well as an efficient tool to allow intercomparison between structured-grid and unstructured-grid approaches. Reference : Burchard, H., Debreu, L., Klingbeil, K., Lemarié, F. : The numerics of hydrostatic structured-grid coastal ocean models: state of the art and future perspectives. Ocean Modell.
Multiprocessing linear algebra algorithms on the CRAY X-MP-2: Experiences with small granularity
Energy Technology Data Exchange (ETDEWEB)
Chen, S.S.; Dongarra, J.J.; Hsiung, C.
1984-08-01
This paper gives a brief overview of the CRAY X-MP-2 general-purpose multiprocessor system and discusses how it can be used effectively to solve problems that have small granularity. An implementation is described for linear algebra algorithms that solve systems of linear equations when the matrix is general and when the matrix is symmetric and positive definite.
Amanzi: An Open-Source Multi-process Simulator for Environmental Applications
Moulton, J. D.; Molins, S.; Johnson, J. N.; Coon, E.; Lipnikov, K.; Day, M.; Barker, E.
2014-12-01
The Advanced Simulation Capabililty for Environmental Management (ASCEM) program is developing an approach and open-source tool suite for standardized risk and performance assessments at legacy nuclear waste sites. These assessments begin with simplified models, and add geometric and geologic complexity as understanding is gained. The Platform toolsets (Akuna) generates these conceptual models and Amanzi provides the computational engine to perform the simulations, returning the results for analysis and visualization. In this presentation we highlight key elements of the design, algorithms and implementations used in Amanzi. In particular, the hierarchical and modular design is aligned with the coupled processes being sumulated, and naturally supports a wide range of model complexity. This design leverages a dynamic data manager and the synergy of two graphs (one from the high-level perspective of the models the other from the dependencies of the variables in the model) to enable this flexible model configuration at run time. Moreover, to model sites with complex hydrostratigraphy, as well as engineered systems, we are developing a dual unstructured/structured capability. Recently, these capabilities have been collected in a framework named Arcos, and efforts have begun to improve interoperability between the unstructured and structured AMR approaches in Amanzi. To leverage a range of biogeochemistry capability from the community (e.g., CrunchFlow, PFLOTRAN, etc.), a biogeochemistry interface library was developed called Alquimia. To ensure that Amanzi is truly an open-source community code we require a completely open-source tool chain for our development. We will comment on elements of this tool chain, including the testing and documentation development tools such as docutils, and Sphinx. Finally, we will show simulation results from our phased demonstrations, including the geochemically complex Savannah River F-Area seepage basins.
Benchmark Comparison for a Multi-Processing Ion Mobility Calculator in the Free Molecular Regime
Shrivastav, Vaibhav; Nahin, Minal; Hogan, Christopher J.; Larriba-Andaluz, Carlos
2017-08-01
A benchmark comparison between two ion mobility and collision cross-section (CCS) calculators, MOBCAL and IMoS, is presented here as a standard to test the efficiency and performance of both programs. Utilizing 47 organic ions, results are in excellent agreement between IMoS and MOBCAL in He and N2, when both programs use identical input parameters. Due to a more efficiently written algorithm and to its parallelization, IMoS is able to calculate the same CCS (within 1%) with a speed around two orders of magnitude faster than its MOBCAL counterpart when seven cores are used. Due to the high computational cost of MOBCAL in N2, reaching tens of thousands of seconds even for small ions, the comparison between IMoS and MOBCAL is stopped at 70 atoms. Large biomolecules (>10000 atoms) remain computationally expensive when IMoS is used in N2 (even when employing 16 cores). Approximations such as diffuse trajectory methods (DHSS, TDHSS) with and without partial charges and projected area approximation corrections can be used to reduce the total computational time by several folds without hurting the accuracy of the solution. These latter methods can in principle be used with coarse-grained model structures and should yield acceptable CCS results.
Cook, Darcy; Ferens, Ken; Kinsner, Witold
Simulated Annealing (SA) has shown to be a successful technique in optimization problems. It has been applied to both continuous function optimization problems, and combinatorial optimization problems. There has been some work in modifying the SA algorithm to apply properties of chaotic processes with the goal of reducing the time to converge to an optimal or a good solution. There are several variations of these chaotic simulated annealing (CSA) algorithms. In this paper a new variation of chaotic simulated annealing is proposed and is applied in solving a combinatorial optimization problem in multiprocessor task allocation. The experiments show the CSA algorithms reach a good solution faster than traditional SA algorithms in many cases because of a wider initial solution search.
Determining Points of a Circular Region Reachable by Joints of a Robot Arm.
1982-10-01
old leading; WoA 0 figure 12. The tInal segment contains sore than one link, Natation is the same as for Figure 10. Proo: Since A does not lie on a...in con taurations Ub and Ilc.) iszt, suppose that A is not the only joint between A and A. on Co so that for sea is Oci<j, LAiAjJ is a chord of C
A Low Overhead Reachability Guaranteed Dynamic Route Discovery Mechanism for Dense MANETs
Sankar, Sharmila
2010-01-01
A crucial issue for a mobile ad hoc network is the handling of a large number of nodes. As more nodes join the mobile ad hoc network, contention and congestion are more likely. The on demand routing protocols which broadcasts control packets to discover routes to the destination nodes, generate a high number of broadcast packets in a larger networks causing contention and collision. We propose an efficient route discovery protocol, which reduces the number of broadcast packet, using controlled flooding technique. The simulation results show that the proposed probabilistic flooding decreases the number of control packets floating in the network during route discovery phase, without lowering the success ratio of path discoveries. Furthermore, the proposed method adapts to the normal network conditions. The results show that up to 70% of control packet traffic is saved in route discovery phase when the network is denser.
On reachable energy resolution of SiPM based scintillation counters for X-ray detection
Kuper, K. E.; Oleynikov, V. P.; Porosev, V. V.; Savinov, G. A.; Drozdowski, W.
2017-01-01
Presently, silicon photomultipliers (SiPMs) are very attractive devices to replace photomultipliers for light detection in many different fields. For example, they could be used in detectors of photons with energies of 20-150 keV for medical and nondestructive testing applications. The small size and high electron gain of SiPMs make them very attractive candidates for pixelated X-ray detectors operating in a photon counting mode. In this research we evaluated the detector performance that can be reached with up-to-date Lu-based scintillators. Application of LYSO:Ce and LFS-3 scintillators provides high count rate capability because of a short scintillator decay time of ~ 40 ns but enables reaching just a moderate energy resolution. Meanwhile, with a LuYAG:Pr scintillator of quite low non-proportionality one can attain much better energy resolution at a reduced rate.
Iachini, Tina; Ruggiero, Gennaro; Ruotolo, Francesco; Schiano di Cola, Armando; Senese, Vincenzo Paolo
2015-01-01
Although the effects of several personality factors on interpersonal space (i.e. social space within personal comfort area) are well documented, it is not clear whether they also extend to peripersonal space (i.e. reaching space). Indeed, no study has directly compared these spaces in relation to pe
Iachini, Tina; Ruggiero, Gennaro; Ruotolo, Francesco; Schiano di Cola, Armando; Senese, Vincenzo Paolo
2015-01-01
Although the effects of several personality factors on interpersonal space (i.e. social space within personal comfort area) are well documented, it is not clear whether they also extend to peripersonal space (i.e. reaching space). Indeed, no study has directly compared these spaces in relation to pe
Within reach but not so reachable: obstacles matter in visual perception of distances.
Morgado, Nicolas; Gentaz, Edouard; Guinet, Eric; Osiurak, François; Palluel-Germain, Richard
2013-06-01
A large number of studies have shown that effort influences the visual perception of reaching distance. These studies have mainly focused on the effects of reach-relevant properties of the body and of the objects that people intend to reach. However, any influence of the reach-relevant properties of the surrounding environment remains still speculative. We investigated this topic in terms of the role of obstacle width in perceiving distances. Participants had to estimate the straight-line distance to a cylinder located just behind a transparent barrier of varying width. The results showed that participants perceived the straight-line distance to the cylinder as being longer when they intended to grasp the cylinder by reaching around a wide transparent barrier rather than by reaching around narrower ones. Interestingly, this effect might be due to the anticipated effort involved in reaching. Together, our results show that reach-relevant properties of the surrounding environment influence perceived distances, thereby supporting an embodied view of the visual perception of space.
Re-verification of a Lip Synchronization Protocol using Robust Reachability
Kordy, Piotr; Langerak, Rom; Polderman, Jan Willem; Bujorianu, Manuela; Fischer, Michael
2010-01-01
The timed automata formalism is an important model for specifying and analysing real-time systems. Robustness is the correctness of the model in the presence of small drifts on clocks or imprecision in testing guards. A symbolic algorithm for the analysis of the robustness of timed automata has been
Reachability and Real-Time Actuation Strategies for the Active SLIP Model
2015-06-01
3325–3332. [2] R. Blickhan, The spring-mass model for running and hopping, Journal of Biomechanics 22 (1989), no. 11/12 1217–1227. [3] R. Blickhan and R...Biomimetics 7 (2012), no. 1 016006. [20] A. Seyfarth, H. Geyer, M. Günther, and R. Blickhan, A movement criterion for running , Journal of Biomechanics 35...AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Running and hopping follow similar patterns
Baier, Christel; Hermanns, H.; Katoen, Joost P.; Haverkort, Boudewijn R.H.M.
2005-01-01
A continuous-time Markov decision process (CTMDP) is a generalization of a continuous-time Markov chain in which both probabilistic and nondeterministic choices co-exist. This paper presents an efficient algorithm to compute the maximum (or minimum) probability to reach a set of goal states within a
On the Reachability Problem for Dynamic Networks of Concurrent Pushdown Systems
Atig, Mohamed Faouzi; Bouajjani, Ahmed
We consider the problem of checking safety properties for concurrent programs. We assume that programs may have (potentially recursive) procedure calls as well as (unbounded) dynamic creation of parallel threads. Each procedure can have a finite number of local variables, and there is a finite number of global variables that can be accessed by all parallel threads. We assume that these variables range over a finite data domain (e.g., booleans).
Towards Perpetual Peace: an Analysis of the reachability of the basic premises of Kant’s Project
Directory of Open Access Journals (Sweden)
Greyce Kelly Cruz de Sousa França
2017-03-01
Full Text Available The present study will seek to analyze Kant’s project with regard, specifically, to its basic premises as conditions of possibility for perpetual peace. Such peace is admittedly an unattainable ideal; however, the attainability of its premises is advocated by Kant. The objective of this article is to verify if the conditions stipulated by it are enough to reach these premises.
Bosse, Stefan
2011-05-01
A new design methodology for parallel and distributed embedded systems is presented using the behavioural hardware compiler ConPro providing an imperative programming model based on concurrently communicating sequential processes (CSP) with an extensive set of interprocess-communication primitives and guarded atomic actions. The programming language and the compiler-based synthesis process enables the design of constrained power- and resourceaware embedded systems with pure Register-Transfer-Logic (RTL) efficiently mapped to FPGA and ASIC technologies. Concurrency is modelled explicitly on control- and datapath level. Additionally, concurrency on data-path level can be automatically explored and optimized by different schedulers. The CSP programming model can be synthesized to hardware (SoC) and software (C,ML) models and targets. A common source for both hardware and software implementation with identical functional behaviour is used. Processes and objects of the entire design can be distributed on different hardware and software platforms, for example, several FPGA components and software executed on several microprocessors, providing a parallel and distributed system. Intersystem-, interprocess-, and object communication is automatically implemented with serial links, not visible on programming level. The presented design methodology has the benefit of high modularity, freedom of choice of target technologies, and system architecture. Algorithms can be well matched to and distributed on different suitable execution platforms and implementation technologies, using a unique programming model, providing a balance of concurrency and resource complexity. An extended case study of a communication protocol used in high-density sensor-actuator networks should demonstrate and compare the design of a hardware and software target. The communication protocol is suited for high-density intra-and interchip networks.
Parallelization of the Wolff single-cluster algorithm
Kaupužs, J.; Rimšāns, J.; Melnik, R. V. N.
2010-02-01
A parallel [open multiprocessing (OpenMP)] implementation of the Wolff single-cluster algorithm has been developed and tested for the three-dimensional (3D) Ising model. The developed procedure is generalizable to other lattice spin models and its effectiveness depends on the specific application at hand. The applicability of the developed methodology is discussed in the context of the applications, where a sophisticated shuffling scheme is used to generate pseudorandom numbers of high quality, and an iterative method is applied to find the critical temperature of the 3D Ising model with a great accuracy. For the lattice with linear size L=1024 , we have reached the speedup about 1.79 times on two processors and about 2.67 times on four processors, as compared to the serial code. According to our estimation, the speedup about three times on four processors is reachable for the O(n) models with n≥2 . Furthermore, the application of the developed OpenMP code allows us to simulate larger lattices due to greater operative (shared) memory available.
Institute of Scientific and Technical Information of China (English)
王新; 杨卫东; 战启帅; 刘伟; 王天放
2014-01-01
大同煤矿集团公司塔山煤矿4号瓦斯抽排孔终孔口径为1200 mm，孔深423畅66 m，孔底位移≯2 m。孔径大、钻孔深、精度高是本工程的主要难点。钻进施工中采用了气动潜孔锤、双壁钻杆气举反循环及组合牙轮多级扩孔等多种工艺，提高了钻进效率，保证了孔身质量，取得了良好的经济效益和社会效益。%The terminal diameter and depth are 1200mm and 423.66m respectively in 4#gas drainage borehole of Tashan coal mine of Datong Coalmine Group Company with displacement less than 2m.The main difficult points in this project are large borehole diameter, deep drilling and high precisiom.Multi-process of pneumatic DTH hammer, double-wall drill pipe air lift reverse circulation and combined cone multilevel reaming were adopted to improve drilling efficiency, ensure well-bore quality, and achieve good economic and social benefits.
Finding EL+ justifications using the Earley parsing algorithm
CSIR Research Space (South Africa)
Nortje, R
2009-12-01
Full Text Available small modules for EL+ entailment based on reachability. The authors extend the current notion of forward reachability to obtain a bi-directional version, and show that the bi-directional reachability algorithm allows the authors to transform EL+ ontology...
Bandwidth-enhanced photopolymer waveguide hologram-based optical backplane
Bi, Hai; Tian, Chuhua; Chen, Ray T.; Han, Xuliang
2005-01-01
As multiprocessing comes into the mainstream, the board-to-board interconnects become even more critical. In a shared-memory multiprocessing system, the shared bus topology is the preferred interconnect scheme because its broadcast nature can be effectively utilized to reduce communication latency, lessen networking complexity, and support cache coherence. In the electrical domain, however, a major performance bottleneck is anticipated due to the restricted bus bandwidth. In this paper, an innovative architecture, optical centralized shared bus, is proposed for use in the multiprocessing systems. This architecture utilizes the terascale bandwidth capacity of substrate-guided optical interconnects, while at the same time, retaining the essential merits of the shared bus topology. Thus, a smooth migration with substantial multiprocessing performance improvement is expected. A conceptual emulation of the shared-memory multiprocessing scheme is demonstrated on a generic PCI subsystem with an optical centralized shared bus. The objective of this effort is to prove the technical feasibility from the architecture standpoint.
Forward Analysis of Dynamic Network of Pushdown Systems Is Easier without Order
Lugiez, Denis
Dynamic networks of Pushdown Systems (PDN in short) have been introduced to perform static analysis of concurrent programs that may spawn threads dynamically. In this model the set of successors of a regular set of configurations can be non-regular, making forward analysis of these models difficult. We refine the model by adding the associative-commutative properties of parallel composition, and we define Presburger weighted tree automata, an extension of weighted automata and tree automata, that accept the set of successors of a regular set of configurations. This allows forward analysis of PDN since these automata have a decidable emptiness problem and are closed under intersection.
CYCLE TIMES ASSIGNMENT OF NONLINEAR DISCRETE EVENT DYNAMIC SYSTEMS
Institute of Scientific and Technical Information of China (English)
CHEN Wende
2000-01-01
In this paper, nonautonomous models of Discrete Event Dynamic Systems (DEDS) are established by min-max function, reachability and observability are defined,the problem on cycle times assignment of DEDS, which corresponds with the important problem on poles assignment of linear systems, is studied. By Gunawardena et al.'Duality Theorem following results are obtained: Cycle times of system can be assigned under state feedback(or output feedback) if and only if system is reachable (or reachable and obserbable).
Gigabit Per Second Data Processing Project
National Aeronautics and Space Administration — The multi-core processor supports several operating systems including state of the art multiprocessing operating systems, such as Linux SMP, and use ANSI C/C++...
Energy Technology Data Exchange (ETDEWEB)
2016-12-06
LibIsopach is a toolkit for high performance distributed immersive visualization, leveraging modern OpenGL. It features a multi-process scenegraph, explicit instance rendering, mesh generation, and three-dimensional user interaction event processing.
Optimization for Solving Workcell Layouts using Gaussian Penalties for Escaping Local Minima
DEFF Research Database (Denmark)
Iversen, Thomas Fridolin; Ellekilde, Lars-Peter
2017-01-01
The main contribution of this paper is a method for optimizing the layout of workcells taking into consideration both the reachability of the robot as well as the expected cycle time. To analyse the reachability for systems using sensors to pose estimate objects, the method uses a combination of ...
Durand, Fabien
2011-01-01
Nivat's conjecture is about the link between the pure periodicity of a subset $M$ of $\\ZZ^2$, i.e., invariance under translation by a fixed vector, and some upper bound on the function counting the number of different rectangular blocks occurring in $M$. Attempts to solve this conjecture have been considered during the last fifteen years. Let $d\\ge 2$. A legitimate extension to a multidimensional setting of the notion of periodicity is to consider sets of $\\ZZ^d$ definable by a first order formula in the Presburger arithmetic $$. With this latter notion and using a powerful criterion due to Muchnik, we solve an analogue of Nivat's conjecture and characterize sets of $\\ZZ^d$ definable in $$ in terms of some functions counting recurrent blocks, that is, blocks occurring infinitely often.
Linear systems theory revisited
Willigenburg, van L.G.; Koning, de W.L.
2008-01-01
This paper investigates and clarifies how different definitions of reachability, observability, controllability, reconstructability and minimality that appear in the control literature, may be equivalent or different, depending on the type of linear system. The differences are caused by (1) whether
Fast parallel recognition of LR language suffixes
Bertsch, E; Nederhof, M.J.
2004-01-01
It is shown that suffix recognition for deterministic context-free languages can be done on a PRAM multi-processor within the upper complexity bounds of the graph reachability problem. (C) 2004 Elsevier B.V. All rights reserved.
NEDAC: A WORM COUNTERMEASURE MECHANISM
African Journals Online (AJOL)
Dr A.B.Ahmed
disruption of services and significant financial losses to government, transportation ... A vulnerability can be exploited by a worm if it is network reachable, provides .... of the detection and containment systems across of local network across two ...
Directory of Open Access Journals (Sweden)
O. Novoa-Farías
2016-01-01
Conclusions: Resistance of enteropathogenic bacteria to various antibiotics used in gastrointestinal infections is high. Rifaximin was active against 99-100% of these enteropathogens at reachable concentrations in the intestine with the recommended dose.
Formal Description and Verification of a Transport Protocol for Local Networks
Institute of Scientific and Technical Information of China (English)
李腊元
1990-01-01
This paper discusses a transport protocol and its formal description techniques for local network.The transport layer function,The transport services and a transport protocol design in a local network architecture model are presente.A transport protocol specification using the finite state automate(FSA)is given.The correcness of the protocol is verified by using the reachability tree technique with respect to the protocol properties of completeness.deadlock and livelock freeness,termination and reachability.
Directory of Open Access Journals (Sweden)
Sajewski Łukasz
2017-03-01
Full Text Available Reachability and minimum energy control of descriptor fractional discrete-time linear systems with different fractional orders are addressed. Using the Weierstrass–Kronecker decomposition theorem of the regular pencil, a solution to the state equation of descriptor fractional discrete-time linear systems with different fractional orders is given. The reachability condition of this class of systems is presented and used for solving the minimum energy control problem. The discussion is illustrated with numerical examples.
A Mobile IPv6 based Distributed Mobility Management Mechanism of Mobile Internet
Yan, Shi; Jiayin, Cheng; Shanzhi, Chen
A flatter architecture is one of the trends of mobile Internet. Traditional centralized mobility management mechanism faces the challenges such as scalability and UE reachability. A MIPv6 based distributed mobility management mechanism is proposed in this paper. Some important network entities and signaling procedures are defined. UE reachability is also considered in this paper through extension to DNS servers. Simulation results show that the proposed approach can overcome the scalability problem of the centralized scheme.
Terahertz cross-phase modulation of an optical mode
DEFF Research Database (Denmark)
Lavrinenko, Andrei; Novitsky, Andrey; Zalkovskij, Maksim
2013-01-01
We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments.......We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments....
Minimum principle and controllability for multiparameter discrete inclusions via derived cones
Directory of Open Access Journals (Sweden)
Aurelian Cernea
2006-01-01
Full Text Available We consider a multiparameter discrete inclusion and we prove that the reachable set of a certain variational multiparameter discrete inclusion is a derived cone in the sense of Hestenes to the reachable set of the discrete inclusion. This result allows to obtain sufficient conditions for local controllability along a reference trajectory and a new proof of the minimum principle for an optimization problem given by a multiparameter discrete inclusion with endpoint constraints.
A Boolean Approach to Unbounded, Fully Symbolic Model Checking of Timed Automata
2003-03-01
reachability properties (these can express safety and bounded-liveness properties [1]). Uppaal2k and Kronos are unbounded, symbolic model checkers that...explicitly enumerate the discrete component of the state space. Kronos uses Difference Bound Matrices (DBMs) as the symbolic representation [19] of the...difference. Note that while Kronos can check arbitrary TCTL formulas, Uppaal2k is limited to checking reachability properties and very restricted liveness
Pseudo-Random Number Generators for Vector Processors and Multicore Processors
DEFF Research Database (Denmark)
Fog, Agner
2015-01-01
Large scale Monte Carlo applications need a good pseudo-random number generator capable of utilizing both the vector processing capabilities and multiprocessing capabilities of modern computers in order to get the maximum performance. The requirements for such a generator are discussed. New ways...
File, Jon; Goedegebuure, Leo
2003-01-01
Real-time systems (An ICT definition) In real-time multiprocessing there is the extra requirement that the system complete its response to any input within a certain critical time. This poses additional problems, particularly in situations where the system is heavily loaded and is subject to many si
An evaluation of parallel optimization for OpenSolaris Network Stack
Energy Technology Data Exchange (ETDEWEB)
Zou, Hongbo; Wu, Wenji; /Fermilab; Sun, Xian-He; /IIT, Chicago; DeMar, Phil; Crawford, Matt; /Fermilab
2010-10-01
Computing is now shifting towards multiprocessing. The fundamental goal of multiprocessing is improved performance through the introduction of additional hardware threads or cores (referred to as 'cores' for simplicity). Modern network stacks can exploit parallel cores to allow either message-based parallelism or connection-based parallelism as a means to enhance performance. OpenSolaris has redesigned and parallelized to better utilize additional cores. Three special technologies, named Softring Set, Soft ring and Squeue are introduced in OpenSolaris for stack parallelization. In this paper, we study the OpenSolaris packet receiving process and its core parallelism optimization techniques. Experiment results show that these techniques allow OpenSolaris to achieve better network I/O performance in multiprocessing environments; however, network stack parallelization has also brought extra overheads for system. An effective and efficient network I/O optimization in multiprocessing environments is required to cross all levers of the network stack from network interface to application.
Multiprocessor DSP for real-time data processing on Earth orbiting scatterometers
Bachmann, A.; Clark, D.; Lux, J.; Steffke, R.
2000-01-01
The implementation of a Multi DSP radar signal processor for a Ku-Band Earth orbiting scatterometer is discussed. A testbed has been assembled using a combination of commercial DSP hardware and spaceflight components to evaluate the proposed multiprocessing approaches. Test results of real-time radar echo processing are presented, as well as proposed designs for future investigation.
Measuring Moral Thinking from a Neo-Kohlbergian Perspective
Thoma, Stephen J.
2014-01-01
The neo-Kohlbergian model revises and extends Lawrence Kohlberg's model of moral reasoning development to better reflect advances in research and theory. In moving from Kohlberg's global stage model to a multi-process description of moral functioning, these modifications are most evident in the ways in which moral thinking is described,…
Measuring Moral Thinking from a Neo-Kohlbergian Perspective
Thoma, Stephen J.
2014-01-01
The neo-Kohlbergian model revises and extends Lawrence Kohlberg's model of moral reasoning development to better reflect advances in research and theory. In moving from Kohlberg's global stage model to a multi-process description of moral functioning, these modifications are most evident in the ways in which moral thinking is described,…
Rapid development of scalable scientific software using a process oriented approach
DEFF Research Database (Denmark)
Friborg, Rune Møllegaard; Vinter, Brian
2011-01-01
Scientific applications are often not written with multiprocessing, cluster computing or grid computing in mind. This paper suggests using Python and PyCSP to structure scientific software through Communicating Sequential Processes. Three scientific applications are used to demonstrate the featur...
Parallelization of TMVA Machine Learning Algorithms
Hajili, Mammad
2017-01-01
This report reflects my work on Parallelization of TMVA Machine Learning Algorithms integrated to ROOT Data Analysis Framework during summer internship at CERN. The report consists of 4 impor- tant part - data set used in training and validation, algorithms that multiprocessing applied on them, parallelization techniques and re- sults of execution time changes due to number of workers.
Run-time mapping: dynamic resource allocation in embedded systems
Braak, ter Timon David
2016-01-01
Many desired features of computing platforms, such as increased fault tolerance, variable quality of service, and improved energy efficiency, can be achieved by postponing resource management decisions from design-time to run-time. While multiprocessing has been widespread in embedded systems for q
Run-time mapping: dynamic resource allocation in embedded systems
ter Braak, T.D.
2016-01-01
Many desired features of computing platforms, such as increased fault tolerance, variable quality of service, and improved energy efficiency, can be achieved by postponing resource management decisions from design-time to run-time. While multiprocessing has been widespread in embedded systems for
Reactive Programming of Cellular Automata
Boussinot, Frédéric
2004-01-01
Implementation of cellular automata using reactive programming gives a way to code cell behaviors in an abstract and modular way. Multiprocessing also becomes possible. The paper describes the implementation of cellular automata with the reactive programming language LOFT, a thread-based extension of C. Self replicating loops considered in artificial life are coded to show the interest of the approach.
Proprioceptive body illusions modulate the visual perception of reaching distance.
Directory of Open Access Journals (Sweden)
Agustin Petroni
Full Text Available The neurobiology of reaching has been extensively studied in human and non-human primates. However, the mechanisms that allow a subject to decide-without engaging in explicit action-whether an object is reachable are not fully understood. Some studies conclude that decisions near the reach limit depend on motor simulations of the reaching movement. Others have shown that the body schema plays a role in explicit and implicit distance estimation, especially after motor practice with a tool. In this study we evaluate the causal role of multisensory body representations in the perception of reachable space. We reasoned that if body schema is used to estimate reach, an illusion of the finger size induced by proprioceptive stimulation should propagate to the perception of reaching distances. To test this hypothesis we induced a proprioceptive illusion of extension or shrinkage of the right index finger while participants judged a series of LEDs as reachable or non-reachable without actual movement. Our results show that reach distance estimation depends on the illusory perceived size of the finger: illusory elongation produced a shift of reaching distance away from the body whereas illusory shrinkage produced the opposite effect. Combining these results with previous findings, we suggest that deciding if a target is reachable requires an integration of body inputs in high order multisensory parietal areas that engage in movement simulations through connections with frontal premotor areas.
Naruse, Takashi; Matsumoto, Hiroshige; Fujisaki-Sakai, Mahiro; Nagata, Satoko
2017-05-30
Home care service demands are increasing in Japan; this necessitates improved service allocation. This study examined the relationship between home visit nursing (HVN) service use and the proportion of elderly people living within 10 min' travel of HVN agencies. The population of elderly people living within reach of HVN agencies for each of 17 municipalities in one low-density prefecture was calculated using public data and geographic information systems. Multilevel logistic analysis for 2641 elderly people was conducted using medical and long-term care insurance claims data from October 2010 to examine the association between the proportion of elderly people reachable by HVNs and service usage in 13 municipalities. Municipality variables included HVN agency allocation appropriateness. Individual variables included HVN usage and demographic variables. The reachable proportion of the elderly population ranged from 0.0 to 90.2% in the examined municipalities. The reachable proportion of the elderly population was significantly positively correlated with HVN use (odds ratio: 1.938; confidence interval: 1.265-2.967). Residents living in municipalities with a lower reachable proportion of the elderly population are less likely to use HVN services. Public health interventions should increase the reachable proportion of the elderly population in order to improve HVN service use.
Improved insensitive to input parameters trajectory clustering algorithm
Institute of Scientific and Technical Information of China (English)
Jiashun Chen; Dechang Pi
2013-01-01
The existing trajectory clustering (TRACLUS) is sensi-tive to the input parameters ε and MinLns. The parameter value is changed a little, but cluster results are entirely different. Aiming at this vulnerability, a shielding parameters sensitivity trajectory cluster (SPSTC) algorithm is proposed which is insensitive to the input parameters. Firstly, some definitions about the core distance and reachable distance of line segment are presented, and then the algorithm generates cluster sorting according to the core dis-tance and reachable distance. Secondly, the reachable plots of line segment sets are constructed according to the cluster sor-ting and reachable distance. Thirdly, a parameterized sequence is extracted according to the reachable plot, and then the final trajec-tory cluster based on the parameterized sequence is acquired. The parameterized sequence represents the inner cluster structure of trajectory data. Experiments on real data sets and test data sets show that the SPSTC algorithm effectively reduces the sensitivity to the input parameters, meanwhile it can obtain the better quality of the trajectory cluster.
Proprioceptive Body Illusions Modulate the Visual Perception of Reaching Distance
Petroni, Agustin; Carbajal, M. Julia; Sigman, Mariano
2015-01-01
The neurobiology of reaching has been extensively studied in human and non-human primates. However, the mechanisms that allow a subject to decide—without engaging in explicit action—whether an object is reachable are not fully understood. Some studies conclude that decisions near the reach limit depend on motor simulations of the reaching movement. Others have shown that the body schema plays a role in explicit and implicit distance estimation, especially after motor practice with a tool. In this study we evaluate the causal role of multisensory body representations in the perception of reachable space. We reasoned that if body schema is used to estimate reach, an illusion of the finger size induced by proprioceptive stimulation should propagate to the perception of reaching distances. To test this hypothesis we induced a proprioceptive illusion of extension or shrinkage of the right index finger while participants judged a series of LEDs as reachable or non-reachable without actual movement. Our results show that reach distance estimation depends on the illusory perceived size of the finger: illusory elongation produced a shift of reaching distance away from the body whereas illusory shrinkage produced the opposite effect. Combining these results with previous findings, we suggest that deciding if a target is reachable requires an integration of body inputs in high order multisensory parietal areas that engage in movement simulations through connections with frontal premotor areas. PMID:26110274
Bernardo, Marco; Loreti, Michele; 10.4204/EPTCS.60.5
2011-01-01
Labeled transition systems are typically used to represent the behavior of nondeterministic processes, with labeled transitions defining a one-step state to-state reachability relation. This model has been recently made more general by modifying the transition relation in such a way that it associates with any source state and transition label a reachability distribution, i.e., a function mapping each possible target state to a value of some domain that expresses the degree of one-step reachability of that target state. In this extended abstract, we show how the resulting model, called ULTraS from Uniform Labeled Transition System, can be naturally used to give semantics to a fully nondeterministic, a fully probabilistic, and a fully stochastic variant of a CSP-like process language.
Analysis of multi-stage open shop processing systems
Eggermont, Christian; Woeginger, Gerhard J
2011-01-01
We study algorithmic problems in multi-stage open shop processing systems that are centered around reachability and deadlock detection questions. We characterize safe and unsafe system states. We show that it is easy to recognize system states that can be reached from the initial state (where the system is empty), but that in general it is hard to decide whether one given system state is reachable from another given system state. We show that the problem of identifying reachable deadlock states is hard in general open shop systems, but is easy in the special case where no job needs processing on more than two machines (by linear programming and matching theory), and in the special case where all machines have capacity one (by graph-theoretic arguments).
On the 2-MRS Problem in a Tree with Unreliable Edges
Directory of Open Access Journals (Sweden)
Wei Ding
2013-01-01
Full Text Available This paper extends the well-known most reliable source (1-MRS problem in unreliable graphs to the 2-most reliable source (2-MRS problem. Two kinds of reachable probability models of node pair in unreliable graphs are considered, that is, the superior probability and united probability. The 2-MRS problem aims to find a node pair in the graph from which the expected number of reachable nodes or the minimum reachability is maximized. It has many important applications in large-scale unreliable computer or communication networks. The #P-hardness of the 2-MRS problem in general graphs follows directly from that of the 1-MRS problem. This paper deals with four models of the 2-MRS problem in unreliable trees where every edge has an independent working probability and devises a cubic-time and quadratic-space dynamic programming algorithm, respectively, for each model.
Mars Science Laboratory CHIMRA/IC/DRT Flight Software for Sample Acquisition and Processing
Kim, Won S.; Leger, Chris; Carsten, Joseph; Helmick, Daniel; Kuhn, Stephen; Redick, Richard; Trujillo, Diana
2013-01-01
The design methodologies of using sequence diagrams, multi-process functional flow diagrams, and hierarchical state machines were successfully applied in designing three MSL (Mars Science Laboratory) flight software modules responsible for handling actuator motions of the CHIMRA (Collection and Handling for In Situ Martian Rock Analysis), IC (Inlet Covers), and DRT (Dust Removal Tool) mechanisms. The methodologies were essential to specify complex interactions with other modules, support concurrent foreground and background motions, and handle various fault protections. Studying task scenarios with multi-process functional flow diagrams yielded great insight to overall design perspectives. Since the three modules require three different levels of background motion support, the methodologies presented in this paper provide an excellent comparison. All three modules are fully operational in flight.
A-MMLQ Algorithm for Multi-level Queue Scheduling
Directory of Open Access Journals (Sweden)
Manupriya Hasija
2013-07-01
Full Text Available This being the era of advancement in computing domain, the emphasis is on better resource scheduling. Scheduling is not confined to dealing multiple tasks by a single processor. It’s a dawn with multiprocessing and multitasking. Although multiprocessor systems impose several overheads but still make the concept amazingly interesting. The scheduling field has taken a whirlwind after the notion of multiprocessing. Many of the uniprocessor algorithms do fit well under the multiprocessor systems but, still necessitating a further development aiming solely on multiprocessor scheduling. This paper thus sketches a new idea to modify and extend the well-known multi-level queue scheduling, taking into account the arrival time/ arrival sequence to conceptualize an innovative scheduling algorithm.
Metadata for fine-grained processing at ATLAS
Cranshaw, Jack; The ATLAS collaboration
2016-01-01
High energy physics experiments are implementing highly parallel solutions for event processing on resources that support concurrency at multiple levels. These range from the inherent large-scale parallelism of HPC resources to the multiprocessing and multithreading needed for effective use of multi-core and GPU-augmented nodes. Such modes of processing, and the efficient opportunistic use of transiently-available resources, lead to finer-grained processing of event data. Previously metadata systems were tailored to jobs that were atomic and processed large, well-defined units of data. The new environment requires a more fine-grained approach to metadata handling, especially with regard to bookkeeping. For opportunistic resources metadata propagation needs to work even if individual jobs are not finalized. This contribution describes ATLAS solutions to this problem in the context of the multiprocessing framework currently in use for LHC Run 2, development underway for the ATLAS multithreaded framework (Athena...
一种检测TAL-freeness的代数方法%An Algebraic Approach for TAL-Freeness Detection
Institute of Scientific and Technical Information of China (English)
彭蓉; 崔竞松; 曾祥勇
2008-01-01
时间动作锁(Time-Action-Lock,TAL)指的是实时系统处于一种时间无法继续同时又没有任何动作能够发生的状态.Behzad和Kozo在时间自动机的几何学基础上提出了一种针对TAL-freeness的检测方法.但该方法要求必须将需要检测的模型转化为一种逻辑语言Rational Presburger Sentences后才能进行检测,因此使得验证过程比较繁琐.文中提出了一种检测TAL-freeness的代数方法,能够直接对系统模型进行直接验证,并且能够定位死锁原因.针对该方法,文中还给出了相应算法并提供了正确性证明与性能分析.
Minimum Energy Control of 2D Positive Continuous-Discrete Linear Systems
Directory of Open Access Journals (Sweden)
Kaczorek Tadeusz
2014-09-01
Full Text Available The minimum energy control problem for the 2D positive continuous-discrete linear systems is formulated and solved. Necessary and sufficient conditions for the reachability at the point of the systems are given. Sufficient conditions for the existence of solution to the problem are established. It is shown that if the system is reachable then there exists an optimal input that steers the state from zero boundary conditions to given final state and minimizing the performance index for only one step (q = 1. A procedure for solving of the problem is proposed and illustrated by a numerical example.
Search Complexities for HTN Planning
2013-01-01
transitive ≤1 constraints are inconsistent. This means there exists a task name c and method m = (c, tnm ) with more than one subtask such that c ≤1...1 c, and so c is a reachable subtask of tnm . Since c is a reachable subtask of tn0, we can decompose tn0 into a task network containing c, then...m = (c, tnm ) and an isomorphism from tnm to the children of that node. Moreover, T (g) is defined to refer to the tasks of g and ch(g, t) to refer to
Wind Corrections in Flight Path Planning
Directory of Open Access Journals (Sweden)
Martin Selecký
2013-05-01
Full Text Available When operating autonomous unmanned aerial vehicles (UAVs in real environments it is necessary to deal with the effects of wind that causes the aircraft to drift in a certain direction. In such conditions it is hard or even impossible for UAVs with a bounded turning rate to follow certain trajectories. We designed a method based on an Accelerated A* algorithm that allows the trajectory planner to take the wind effects into account and to generate states that are reachable by UAV. This method was tested on hardware UAV and the reachability of its generated trajectories was compared to the trajectories computed by the original Accelerated A*.
On Time with Minimal Expected Cost!
DEFF Research Database (Denmark)
David, Alexandre; Jensen, Peter Gjøl; Larsen, Kim Guldstrand
2014-01-01
) timed game essentially defines an infinite-state Markov (reward) decision proces. In this setting the objective is classically to find a strategy that will minimize the expected reachability cost, but with no guarantees on worst-case behaviour. In this paper, we provide efficient methods for computing...... reachability strategies that will both ensure worst case time-bounds as well as provide (near-) minimal expected cost. Our method extends the synthesis algorithms of the synthesis tool Uppaal-Tiga with suitable adapted reinforcement learning techniques, that exhibits several orders of magnitude improvements w...
Reconnectable Network with Limited Resources
Institute of Scientific and Technical Information of China (English)
史维更
1991-01-01
The reachability of a strongly connected network may be destroyed after link damage.Since many networks are directed or equivalent directed,connected by directed links with the potential for reversal.Therefore the reachability can be restored by reversing the direction of links.[1] has studied this matter under unlimited resources (transmitter and receiver) condition.In this paper the reconnectability of a network with limited number of receivers and transmitters is discussed.Also a linear time algorithm is given to find a reconnected reversal for limited receivers and transmitters.
Symbolic Algorithmic Analysis of Rectangular Hybrid Systems
Institute of Scientific and Technical Information of China (English)
Hai-Bin Zhang; Zhen-Hua Duan
2009-01-01
This paper investigates symbolic algorithmic analysis of rectangular hybrid systems. To deal with the symbolic reachability problem, a restricted constraint system called hybrid zone is formalized for the representation and manipulation of rectangular automata state-spaces. Hybrid zones are proved to be closed over symbolic reachability operations of rectangular hybrid systems. They are also applied to model-checking procedures for verifying some important classes of timed computation tree logic formulas. To represent hybrid zones, a data structure called difference constraint matrix is defined.These enable us to deal with the symbolic algorithmic analysis of rectangular hybrid systems in an efficient way.
Modelling and Analysis of Real Time Systems with Logic Programming and Constraints
DEFF Research Database (Denmark)
Banda, Gourinath
minimal model forms the basis for verifying the LHA model. We consider two techniques to verify the reactive properties specified as CTL formulas: (i) reachability analysis and (ii) model checking. A systematic translation of LHA models into constraint logic programs is de- fined. This is mechanised...... by a compiler. To facilitate forward and backward reasoning, two different ways to model an LHA are defined. A framework consist- ing of general purpose constraint logic program tools is presented to accomplish the reachability analysis to verify a class of safety and liveness properties. A tool to compute...
Wind Corrections in Flight Path Planning
Directory of Open Access Journals (Sweden)
Martin Selecký
2013-05-01
Full Text Available Abstract When operating autonomous unmanned aerial vehicles (UAVs in real environments it is necessary to deal with the effects of wind that causes the aircraft to drift in a certain direction. In such conditions it is hard or even impossible for UAVs with a bounded turning rate to follow certain trajectories. We designed a method based on an Accelerated A* algorithm that allows the trajectory planner to take the wind effects into account and to generate states that are reachable by UAV. This method was tested on hardware UAV and the reachability of its generated trajectories was compared to the trajectories computed by the original Accelerated A*.
2008-04-01
ensure the success of their child, failure is not often experienced. These successes and the ease of childhood lead to not only confidence but an...Messaging, chatting on the cell phone and working on homework is a common place scene for teens and college students. “The level of multiprocessing...to Gen Yers entering the workforce with unrealistic expectations and a sense of entitlement. Barbara Dwyer, CEO of the Job Journey, states that
Acoustic simulation in architecture with parallel algorithm
Li, Xiaohong; Zhang, Xinrong; Li, Dan
2004-03-01
In allusion to complexity of architecture environment and Real-time simulation of architecture acoustics, a parallel radiosity algorithm was developed. The distribution of sound energy in scene is solved with this method. And then the impulse response between sources and receivers at frequency segment, which are calculated with multi-process, are combined into whole frequency response. The numerical experiment shows that parallel arithmetic can improve the acoustic simulating efficiency of complex scene.
Computer programming and architecture the VAX
Levy, Henry
2014-01-01
Takes a unique systems approach to programming and architecture of the VAXUsing the VAX as a detailed example, the first half of this book offers a complete course in assembly language programming. The second describes higher-level systems issues in computer architecture. Highlights include the VAX assembler and debugger, other modern architectures such as RISCs, multiprocessing and parallel computing, microprogramming, caches and translation buffers, and an appendix on the Berkeley UNIX assembler.
National Research Council Canada - National Science Library
Gillespie, Thom
1997-01-01
... useful for a working programmer moving from C++ to Java. Threads are what makes Java a particularly useful language for multiprocessing--the ability to appear to do more than one thing at a time--which is what the Internet is all about. The tricky part of threads is that the concept is new for most users. Oaks offers a very clear discussion of how t...
Enhanced Inclusion Removal from Steel in the Tundish
Energy Technology Data Exchange (ETDEWEB)
R. C. Bradt; M.A.R. Sharif
2009-09-25
The objective of this project was to develop an effective chemical filtering system for significantly reducing the content of inclusion particles in the steel melts exiting the tundish for continuous casting. This project combined a multi-process approach that aimed to make significant progress towards an "inclusion free" steel by incorporating several interdependent concepts to reduce the content of inclusions in the molten steel exiting the tundish for the caster. The goal is to produce "cleaner" steel.
Enhanced Incluison Removal from Steel in the Tundish
Energy Technology Data Exchange (ETDEWEB)
R.C. Bradt; M.A.R. Sharif
2009-09-25
The objective of this project was to develop an effective chemical filtering system for significantly reducing the content of inclusion particles in the steel melts exiting the tundish for continuous casting. This project combined a multi-process approach that aimed to make significant progress towards an "inclusion free" steel by incorporating several interdependent concepts to reduce the content of inclusions in the molten steel exiting the tundish for the caster. The goal is to produce "cleaner" steel.
The Interface Between Distributed Operating System and High-Level Programming Language. Revision.
1986-09-01
O.S. pair. Relatively little attention has been devoted to the relationship between languages and O.S. kernels in a distributed setting. Amoeba [161...interaction not only between the pieces of a multi-process appli- cation, but also between separate applications and between user programs and long- lived ...a process the right to send requests (it is still free to send replies). Allow restores that right. Retry is equivalent to forbid followed by allon
Solute transport through porous media using asymptotic dispersivity
Indian Academy of Sciences (India)
P K Sharma; Teodrose Atnafu Abgaze
2015-08-01
In this paper, multiprocess non-equilibrium transport equation has been used, which accounts for both physical and chemical non-equilibrium for reactive transport through porous media. An asymptotic distance dependent dispersivity is used to embrace the concept of scale-dependent dispersion for solute transport in heterogeneous porous media. Semi-analytical solution has been derived of the governing equations with an asymptotic distance dependent dispersivity by using Laplace transform technique and the power series method. For application of analytical model, we simulated observed experimental breakthrough curves from 1500 cm long soil column experiments conducted in the laboratory. The simulation results of break-through curves were found to deviate from the observed breakthrough curves for both mobile–immobile and multiprocess non-equilibrium transport with constant dispersion models. However, multiprocess non-equilibrium with an asymptotic dispersion model gives better fit of experimental breakthrough curves through long soil column and hence it is more useful for describing anomalous solute transport through hetero-geneous porous media. The present model is simpler than the stochastic numerical method.
Verification and Performance Evaluation of Timed Game Strategies
DEFF Research Database (Denmark)
David, Alexandre; Fang, Huixing; Larsen, Kim Guldstrand;
2014-01-01
Control synthesis techniques, based on timed games, derive strategies to ensure a given control objective, e.g., time-bounded reachability. Model checking verifies correctness properties of systems. Statistical model checking can be used to analyse performance aspects of systems, e.g., energy...
2007-01-01
Please note that starting from 1 March 2007, the shuttle requests: for official visits or bidders' conferences on the CERN site; towards/from the airport or central Geneva; for long distances, shall be made via Fm.Support@cern.ch or by calling 77777. The radio taxi will still be reachable at 76969. TS/FM Group
SBOAT: A Stochastic BPMN Analysis and Optimisation Tool
DEFF Research Database (Denmark)
Herbert, Luke Thomas; Hansen, Zaza Nadja Lee; Jacobsen, Peter
2014-01-01
exploration of the space of possible models. We present a simple example of a distributed stochastic system where we determine a reachability property and the value of associated rewards in states of interest for a generated range of models. This example is taken from a case company in the Danish baking...
MINIMAL RATIONAL INTERPOLATION AND PRONYS METHOD
ANTOULAS, AC; WILLEMS, JC
1990-01-01
A new method is proposed for dealing with the rational interpolation problem. It is based on the reachability of an appropriately defined pair of matrices. This method permits a complete clarification of several issues raised, but not answered, by the so-called Prony method of fitting a linear model
Decidable Fragments of a Higher Order Calculus with Locations
DEFF Research Database (Denmark)
Hüttel, Hans; Godskesen, Jens Christian; Haagensen, Bjørn
2009-01-01
Homer is a higher order process calculus with locations. In this paper we study Homer in the setting of the semantic finite control property, which is a finite reachability criterion that implies decidability of barbed bisimilarity. We show that strong and weak barbed bisimilarity are undecidable...... control π-calculus in Homer....
Luo, Chao; Wang, Xingyuan; Liu, Hong
2014-01-01
In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) with time delay is studied. Firstly, dynamical model of Boolean multiplex control networks is constructed, which is assumed to be under Harvey' asynchronous update and time delay is introduced both in states and controls. By using of semi-tensor product (STP) approach, the logical dynamics is converted into an equivalent algebraic form by obtaining the control-depending network transition matrices of delayed system. Secondly, a necessary and sufficient condition is proved that only control-depending fixed points of the studied dynamics can be controlled with probability one. Thirdly, respectively for two types of controls, the controllability of dynamical control system is investigated. When initial states and time delay are given, formulae are obtained to show a) the reachable set at time s under specified controls; b) the reachable set at time s under arbitrary controls; c) the reachable probabilities to different destination states. Furthermore, an approach is discussed to find a precise control sequence which can steer dynamical system into a specified target with the maximum reachable probability. Examples are shown to illustrate the feasibility of the proposed scheme. PMID:25516009
Passivity-based sliding mode control for a polytopic stochastic differential inclusion system.
Liu, Leipo; Fu, Zhumu; Song, Xiaona
2013-11-01
Passivity-based sliding mode control for a polytopic stochastic differential inclusion (PSDI) system is considered. A control law is designed such that the reachability of sliding motion is guaranteed. Moreover, sufficient conditions for mean square asymptotic stability and passivity of sliding mode dynamics are obtained by linear matrix inequalities (LMIs). Finally, two examples are given to illustrate the effectiveness of the proposed method.
Tool Use Affects Perceived Distance, but Only when You Intend to Use It
Witt, Jessica K.; Proffitt, Dennis R.; Epstein, William
2005-01-01
Recent research demonstrates neurologic and behavioral differences in people's responses to the space that is within and beyond reach. The present studies demonstrated a perceptual difference as well. Reachability was manipulated by having participants reach with and without a tool. Across 2 conditions, in which participants either held a tool or…
Normal forms for sub-Lorentzian metrics supported on Engel type distributions
Grochowski, Marek
2014-06-01
We construct normal forms for Lorentzian metrics on Engel distributions under the assumption that abnormal curves are timelike future directed Hamiltonian geodesics. Then we indicate some cases in which the abnormal timelike future directed curve initiating at the origin is geometrically optimal. We also give certain estimates for reachable sets from a point.
Constrained motion model of mobile robots and its applications.
Zhang, Fei; Xi, Yugeng; Lin, Zongli; Chen, Weidong
2009-06-01
Target detecting and dynamic coverage are fundamental tasks in mobile robotics and represent two important features of mobile robots: mobility and perceptivity. This paper establishes the constrained motion model and sensor model of a mobile robot to represent these two features and defines the k -step reachable region to describe the states that the robot may reach. We show that the calculation of the k-step reachable region can be reduced from that of 2(k) reachable regions with the fixed motion styles to k + 1 such regions and provide an algorithm for its calculation. Based on the constrained motion model and the k -step reachable region, the problems associated with target detecting and dynamic coverage are formulated and solved. For target detecting, the k-step detectable region is used to describe the area that the robot may detect, and an algorithm for detecting a target and planning the optimal path is proposed. For dynamic coverage, the k-step detected region is used to represent the area that the robot has detected during its motion, and the dynamic-coverage strategy and algorithm are proposed. Simulation results demonstrate the efficiency of the coverage algorithm in both convex and concave environments.
Marketing Your Library Program--More than a PR Campaign.
Brown, Gerald R.
In this workshop, the concept of marketing was applied to school library media programs by examining the relationship between library media programs, the marketing plan, public relations (PR), and promotion. Reachable goals, targeting the audience, advertising, and motivation and commitment of the staff were also considered, and successful…
Solving Simple Stochastic Games with Few Random Vertices
Gimbert, H.; Horn, F.
2009-01-01
Simple stochastic games are two-player zero-sum stochastic games with turn-based moves, perfect information, and reachability winning conditions. We present two new algorithms computing the values of simple stochastic games. Both of them rely on the existence of optimal permutation strategies, a cla
Interface Design Optimization by an Improved Operating Model for College Students
Ko, Ya-Chuan; Lo, Chi-Hung; Hsiao, Shih-Wen
2017-01-01
A method was proposed in this study for assessing the interface operating efficiency of a remote control. The operating efficiency of a product interface can be determined by the proposed approach in which the related dimensions of human palms were measured. The reachable range (blue zone) and the most comfortable range (green zone) were…
Providing evidence of likely being on time – Counterexample generation for CTMC model checking
Han, T.; Katoen, J.P.; Namjoshi, K.; Yoneda, T.; Higashino, T.; Okamura, Y.
2007-01-01
Probabilistic model checkers typically provide a list of individual state probabilities on the refutation of a temporal logic formula. For large state spaces, this information is far too detailed to act as useful diagnostic feedback. For quantitative (constrained) reachability problems, sets of path
Dynamic Mobile IP routers in ad hoc networks
Kock, B.A.; Schmidt, J.R.
2005-01-01
This paper describes a concept combining mobile IP and ad hoc routing to create a robust mobile network. In this network all nodes are mobile and globally and locally reachable under the same IP address. Essential for implementing this network are the dynamic mobile IP routers. They act as gateways
Journal of the Nigerian Association of Mathematical Physics - Vol 11 ...
African Journals Online (AJOL)
A new analytical solution to the diffusion problem: Fourier series method · EMAIL ... of solution and reachable sets of quantum stochastic differential inclusions · EMAIL ... Horizontal and vertical projectile motion in a resistant medium under the .... Incremental cryptography and security of public hash functions · EMAIL FULL ...
Minimal Function Graphs are not Instrumented
DEFF Research Database (Denmark)
Mycroft, Alan; Rosendahl, Mads
1992-01-01
The minimal function graph semantics of Jones and Mycroft is a standard denotational semantics modified to include only `reachable' parts of a program. We show that it may be expressed directly in terms of the standard semantics without the need for instrumentation at the expression level and, in...
How non-zero initial conditions affect the minimality of linear discrete-time systems
Willigenburg, van L.G.; Koning, de W.L.
2008-01-01
From the state-space approach to linear systems, promoted by Kalman, we learned that minimality is equivalent with reachability together with observability. Our past research on optimal reduced-order LQG controller synthesis revealed that if the initial conditions are non-zero, minimality is no long
The moon as a detector of ultra-high-energy neutrinos
Scholten, Olaf; Bijker, R
2012-01-01
Cosmogenic particles at ultra-high energies (UHE, E > 10(20) eV, about 1 Joule) are the messengers of the most energetic processes in the universe. Their energy is orders of magnitude higher than reachable at CERN. The quest is to find their origin. Neutrinos are especially suited for this as they
Lower and Upper Bounds in Zone-Based Abstractions of Timed Automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Bouyer, Patricia; Larsen, Kim Guldstrand;
2005-01-01
be obtained. We show soundness and completeness of the new abstractions w.r.t. reachability and demonstrate how information about lower and upper bounds can be used to optimise the algorithm for bringing a difference bound matrix into normal form. Finally, we experimentally demonstrate that the new techniques...
Lower and Upper Bounds in Zone-Based Abstractions of Timed Automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Bouyer, P.; Larsen, Kim Guldstrand;
2005-01-01
, significantly coarser abstractions can be obtained. We show soundness and completeness of the new abstractions w.r.t. reachability. We demonstrate how information about lower and upper bounds can be used to optimise the algorithm for bringing a difference bound matrix into normal form. Finally, we...
The moon as a detector of ultra-high-energy neutrinos
Scholten, Olaf
2012-01-01
Cosmogenic particles at ultra-high energies (UHE, E >1020 eV, about 1 Joule) are the messengers of the most energetic processes in the universe. Their energy is orders of magnitude higher than reachable at CERN. The quest is to find their origin. Neutrinos are especially suited for this as they fly
The moon as a detector of ultra-high-energy neutrinos
Scholten, Olaf; Bijker, R
2012-01-01
Cosmogenic particles at ultra-high energies (UHE, E > 10(20) eV, about 1 Joule) are the messengers of the most energetic processes in the universe. Their energy is orders of magnitude higher than reachable at CERN. The quest is to find their origin. Neutrinos are especially suited for this as they f
Symmetry reduction for stochastic hybrid systems
Bujorianu, L.M.; Katoen, J.P.
2009-01-01
This paper is focused on adapting symmetry reduction, a technique that is highly successful in traditional model checking, to stochastic hybrid systems. We first show that performability analysis of stochastic hybrid systems can be reduced to a stochastic reachability analysis (SRA). Then, we genera
Symmetry Reduction For Stochastic Hybrid Systems
Bujorianu, L.M.; Katoen, J.P.
2008-01-01
This paper is focused on adapting symmetry reduction, a technique that is highly successful in traditional model checking, to stochastic hybrid systems. To that end, we first show that performability analysis of stochastic hybrid systems can be reduced to a stochastic reachability analysis (SRA). Th
Systematic realisation of control flow analyses for CML
DEFF Research Database (Denmark)
Gasser, K.L.S.; Nielson, Flemming; Nielson, Hanne Riis
1997-01-01
for terminating w well as non-terminating programs. The analysis is defined coinductively and it is shown that all programs have a least analysis result (that is indeed the best one). To realise the analysis we massage the specification in three stages: (i) to explicitly record reachability of subexpressions, (ii...
Luo, Chao; Wang, Xingyuan; Liu, Hong
2014-12-17
In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) with time delay is studied. Firstly, dynamical model of Boolean multiplex control networks is constructed, which is assumed to be under Harvey' asynchronous update and time delay is introduced both in states and controls. By using of semi-tensor product (STP) approach, the logical dynamics is converted into an equivalent algebraic form by obtaining the control-depending network transition matrices of delayed system. Secondly, a necessary and sufficient condition is proved that only control-depending fixed points of the studied dynamics can be controlled with probability one. Thirdly, respectively for two types of controls, the controllability of dynamical control system is investigated. When initial states and time delay are given, formulae are obtained to show a) the reachable set at time s under specified controls; b) the reachable set at time s under arbitrary controls; c) the reachable probabilities to different destination states. Furthermore, an approach is discussed to find a precise control sequence which can steer dynamical system into a specified target with the maximum reachable probability. Examples are shown to illustrate the feasibility of the proposed scheme.
Controllability in nonlinear systems
Hirschorn, R. M.
1975-01-01
An explicit expression for the reachable set is obtained for a class of nonlinear systems. This class is described by a chain condition on the Lie algebra of vector fields associated with each nonlinear system. These ideas are used to obtain a generalization of a controllability result for linear systems in the case where multiplicative controls are present.
DEFF Research Database (Denmark)
Kölker, Jonas
2012-01-01
In a Kurdoko puzzle,one must colour some squares in a grid black in a way that satisfies non-overlapping, non-adjacency, reachability and numeric constraints specified by the numeric clues in the grid. We show that deciding the solvability of Kurodoko puzzles is NP-complete....
Condensed State Spaces for Symmetrical Coloured Petri Nets
DEFF Research Database (Denmark)
Jensen, Kurt
1996-01-01
This paper deals with state spaces. A state space is a directed graph with a node for each reachable state and an arc for each possible state change. We describe how symmetries of the modelled system can be exploited to obtain much more succinct state space analysis. The symmetries induce equival...
Efficient Approximation of Optimal Control for Markov Games
DEFF Research Database (Denmark)
Fearnley, John; Rabe, Markus; Schewe, Sven
2011-01-01
We study the time-bounded reachability problem for continuous-time Markov decision processes (CTMDPs) and games (CTMGs). Existing techniques for this problem use discretisation techniques to break time into discrete intervals, and optimal control is approximated for each interval separately...
Timed-Arc Petri Nets vs. Networks of Timed Automata
DEFF Research Database (Denmark)
Srba, Jiri
requirement and provide efficient (polynomial time) reductions between networks of timed automata and 1-safe timed-arc Petri nets preserving the answer to the reachability question. This makes our techniques suitable for automatic translation into a format required by tools like UPPAAL and KRONOS. A direct...
Recursion vs. Replication in Simple Cryptographic Protocols
DEFF Research Database (Denmark)
Huttel, Hans; Srba, Jiri
2005-01-01
We use some recent techniques from process algebra to draw several conclusions about the well studied class of ping-pong protocols introduced by Dolev and Yao. In particular we show that all nontrivial properties, including reachability and equivalence checking wrt. the whole van Glabbeek's spect...
DEFF Research Database (Denmark)
Huttel, Hans; Srba, Jiri
2004-01-01
This paper introduces a process calculus with recursion which allows us to express an unbounded number of runs of the ping-pong protocols introduced by Dolev and Yao. We study the decidability issues associated with two common approaches to checking security properties, namely reachability analys...
Recursion Versus Replication in Simple Cryptographic Protocols
DEFF Research Database (Denmark)
Hüttel, Hans; Srba, Jiri
2005-01-01
We use some very recent techniques from process algebra to draw interesting conclusions about the well studied class of ping-pong protocols introduced by Dolev and Yao. In particular we show that all nontrivial properties, including reachability and equivalence checking wrt. the whole van Glabbee...
Decidability Issues for Extended Ping-Pong Protocols
DEFF Research Database (Denmark)
Huttel, Hans; Srba, Jiri
2006-01-01
We use some recent techniques from process algebra to draw several conclusions about the well studied class of ping-pong protocols introduced by Dolev and Yao. In particular we show that all nontrivial properties, including reachability and equivalence checking wrt. the whole van Glabbeek's spect...
On a Result for Finite Markov Chains
Kulathinal, Sangita; Ghosh, Lagnojita
2006-01-01
In an undergraduate course on stochastic processes, Markov chains are discussed in great detail. Textbooks on stochastic processes provide interesting properties of finite Markov chains. This note discusses one such property regarding the number of steps in which a state is reachable or accessible from another state in a finite Markov chain with M…
Dynamic Mobile IP routers in ad hoc networks
Kock, B.A.; Schmidt, J.R.
2005-01-01
This paper describes a concept combining mobile IP and ad hoc routing to create a robust mobile network. In this network all nodes are mobile and globally and locally reachable under the same IP address. Essential for implementing this network are the dynamic mobile IP routers. They act as gateways
On using priced timed automata to achieve optimal scheduling
DEFF Research Database (Denmark)
Rasmussen, Jacob Illum; Larsen, Kim Guldstrand; Subramani, K.
2006-01-01
projects VHS (VHS 2005) and AMETIST (AMETIST 2005) and are available in the recently released UPPAAL CORA (UPPAAL CORA 2005), a variant of the real-time verification tool UPPAAL (Larsen, Pettersson, & Yi 1997; Behrmann, David, & Larsen 2004) specialized for cost-optimal reachability for the extended model...
DEFF Research Database (Denmark)
Rydhög, Jonas Scherman; Mortensen, Steen Riisgaard; Larsen, Klaus Richter
2016-01-01
We analysed the positional and structural stability of a long-term biodegradable liquid fiducial marker (BioXmark) for radiotherapy in patients with locally advanced lung cancer. Markers were injected via endoscopic- or endobronchial ultrasound in lymph nodes and reachable primary tumours. Marker...
Verification of Liveness Properties on Closed Timed-Arc Petri Nets
DEFF Research Database (Denmark)
Andersen, Mathias; Larsen, Heine G.; Srba, Jiri
2012-01-01
Verification of closed timed models by explicit state-space exploration methods is an alternative to the wide-spread symbolic techniques based on difference bound matrices (DBMs). A few experiments found in the literature confirm that for the reachability analysis of timed automata explicit techn...
46 CFR 132.130 - Fire stations.
2010-10-01
... contains space assigned for the stowage of combustibles, must be reachable by at least two streams of water..., may be used for any purpose except fire-fighting, fire drills, and testing. (m) A suitable hose rack or other device must be provided for each fire hose. Each rack on a weather deck must be placed so...
Recursive Advice for Coordination
DEFF Research Database (Denmark)
Terepeta, Michal Tomasz; Nielson, Hanne Riis; Nielson, Flemming
2012-01-01
makes analyzing such languages more difficult due to the fact that aspects can be recursive - advice from an aspect must itself be analyzed by aspects - as well as being simultaneously applicable in concurrent threads. Therefore the problem of reachability of various states of a system becomes much more...
Automated deadlock detection in synchronized reentrant multithreaded call-graphs
I. Grabe (Immo); F.S. de Boer (Frank); J. van Leeuwen (Jan); A. Muscholl; D. Peleg; J. Pokorny; B. Rumpe
2010-01-01
textabstractIn this paper we investigate the synchronization of multithreaded call graphs with reentrance similar to call graphs in Java programs. We model the individual threads as Visibly Pushdown Automata (VPA) and analyse the reachability of a state in the product automaton by means of a Context
Overview of SM and Higgs results at ATLAS and CMS
Massironi, Andrea
2017-01-01
Recent results on Standard Model and Higgs boson measurements performed by ATLAS and CMS collaborations are reported. The presentation includes results based on LHC Run II data, with particular relevance on most recent ones. Precision measurements reachable with Run II data are discussed, such as the most up-to-date differential distributions.
An Integrated Architecture for Engineering Problem Solving
1998-12-01
62 Figure 33: Constrained attainable envisionment heuristic............................................63 Figure 34: Problem 4.21...collection of qualitative states and transitions that describe the behavior of the system is called an envisionment (de Kleer, 1977). There are two...types of envisionments commonly used for analyzing systems. An attainable envisionment describes all states that are reachable from a given initial
IP MULTICAST GROUP MANAGEMENT FOR BROADCAST LANS DISTRIBUTION
Institute of Scientific and Technical Information of China (English)
Amjad; M.T.; Said(
2001-01-01
［1］Milner R, Parrow J, Walker D. A calculus of mobile processes[J]. Information and computation, 1992,100:1～77.［2］Milner R. Communication and Concurrency[M]. [s.l.]： Prentice Hall, 1989.［3］Pierce B, Sangiorgi D. Typing and subtyping for mobile processes[J]. Journal of Mathematical Structures in Computer Science, 1996,6(5):409～453.［4］Dam M. On the decidability of process equivalence for the π-calculus[J]. Theoretical Computer Science,1997,163:214～228.［5］Montanari U, Pistore M. Checking bismilarity for finitary π-calculus[A]. CONCUR'95[C]. Lecture Notes in Computer Science 962, Springer, 1995.42～56.［6］Victor B, Moller F. The mobility workbench--A tool for the π-calculus[A]. CAV'94[C]. Lecture Notes in Comuter Science 8188, Springer,1994.428～440.［7］李舟军.传值CCS和π-演算中互模拟等价的验证理论与算法[D].长沙：国防科技大学,1999.［8］Lin H. Symbolic transition graph with assignment[A]. CONCUR'96 [C], Lecture Notes in Computer Science 1119,Springer, 1996.50～65.［9］Boreale M, De Nicola R. A symbolic semantis for the π-calculus[J]. Information and Computation, 1996,126:34～52.［10］Pugh W, Bultan T, Gerber R. Symbolic model checking of infinite state systems using Presberger arithmetic [A].CAV'97[C]. Lecture Notes in Computer Science 1254, Springer, 1997.［11］Wolper P, Boigelot B. An automata-theoretic approach to Presburger arithmetic constraints[A]. Proceedings of Static Analysis Symposium[C]. Lecture in Computer Science 983, Springer, 1995.21～32.
ROBUST DISSIPATIVE CONTROL FOR STATE-DELAYED SYSTEMS WITH DISSIPATIVE UNCERTAINTY
Institute of Scientific and Technical Information of China (English)
LI; Zhi-hu(
2001-01-01
［1］Milner R, Parrow J, Walker D. A calculus of mobile processes[J]. Information and computation, 1992,100:1～77.［2］Milner R. Communication and Concurrency[M]. [s.l.]： Prentice Hall, 1989.［3］Pierce B, Sangiorgi D. Typing and subtyping for mobile processes[J]. Journal of Mathematical Structures in Computer Science, 1996,6(5):409～453.［4］Dam M. On the decidability of process equivalence for the π-calculus[J]. Theoretical Computer Science,1997,163:214～228.［5］Montanari U, Pistore M. Checking bismilarity for finitary π-calculus[A]. CONCUR'95[C]. Lecture Notes in Computer Science 962, Springer, 1995.42～56.［6］Victor B, Moller F. The mobility workbench--A tool for the π-calculus[A]. CAV'94[C]. Lecture Notes in Comuter Science 8188, Springer,1994.428～440.［7］李舟军.传值CCS和π-演算中互模拟等价的验证理论与算法[D].长沙：国防科技大学,1999.［8］Lin H. Symbolic transition graph with assignment[A]. CONCUR'96 [C], Lecture Notes in Computer Science 1119,Springer, 1996.50～65.［9］Boreale M, De Nicola R. A symbolic semantis for the π-calculus[J]. Information and Computation, 1996,126:34～52.［10］Pugh W, Bultan T, Gerber R. Symbolic model checking of infinite state systems using Presberger arithmetic [A].CAV'97[C]. Lecture Notes in Computer Science 1254, Springer, 1997.［11］Wolper P, Boigelot B. An automata-theoretic approach to Presburger arithmetic constraints[A]. Proceedings of Static Analysis Symposium[C]. Lecture in Computer Science 983, Springer, 1995.21～32.
RESEARCH ON THE DYNAMIC MATHEMATICAL MODELOF REHEATING FURNACE
Institute of Scientific and Technical Information of China (English)
XU; Li-yun(
2001-01-01
［1］Milner R, Parrow J, Walker D. A calculus of mobile processes[J]. Information and computation, 1992,100:1～77.［2］Milner R. Communication and Concurrency[M]. [s.l.]： Prentice Hall, 1989.［3］Pierce B, Sangiorgi D. Typing and subtyping for mobile processes[J]. Journal of Mathematical Structures in Computer Science, 1996,6(5):409～453.［4］Dam M. On the decidability of process equivalence for the π-calculus[J]. Theoretical Computer Science,1997,163:214～228.［5］Montanari U, Pistore M. Checking bismilarity for finitary π-calculus[A]. CONCUR'95[C]. Lecture Notes in Computer Science 962, Springer, 1995.42～56.［6］Victor B, Moller F. The mobility workbench--A tool for the π-calculus[A]. CAV'94[C]. Lecture Notes in Comuter Science 8188, Springer,1994.428～440.［7］李舟军.传值CCS和π-演算中互模拟等价的验证理论与算法[D].长沙：国防科技大学,1999.［8］Lin H. Symbolic transition graph with assignment[A]. CONCUR'96 [C], Lecture Notes in Computer Science 1119,Springer, 1996.50～65.［9］Boreale M, De Nicola R. A symbolic semantis for the π-calculus[J]. Information and Computation, 1996,126:34～52.［10］Pugh W, Bultan T, Gerber R. Symbolic model checking of infinite state systems using Presberger arithmetic [A].CAV'97[C]. Lecture Notes in Computer Science 1254, Springer, 1997.［11］Wolper P, Boigelot B. An automata-theoretic approach to Presburger arithmetic constraints[A]. Proceedings of Static Analysis Symposium[C]. Lecture in Computer Science 983, Springer, 1995.21～32.
ALGORITHM FOR VERIFYING STRONG OPEN BISIMULATION IN FULL
Institute of Scientific and Technical Information of China (English)
DENG; Yu-xin(
2001-01-01
［1］Milner R, Parrow J, Walker D. A calculus of mobile processes[J]. Information and computation, 1992,100:1～77.［2］Milner R. Communication and Concurrency[M]. [s.l.]： Prentice Hall, 1989.［3］Pierce B, Sangiorgi D. Typing and subtyping for mobile processes[J]. Journal of Mathematical Structures in Computer Science, 1996,6(5):409～453.［4］Dam M. On the decidability of process equivalence for the π-calculus[J]. Theoretical Computer Science,1997,163:214～228.［5］Montanari U, Pistore M. Checking bismilarity for finitary π-calculus[A]. CONCUR'95[C]. Lecture Notes in Computer Science 962, Springer, 1995.42～56.［6］Victor B, Moller F. The mobility workbench--A tool for the π-calculus[A]. CAV'94[C]. Lecture Notes in Comuter Science 8188, Springer,1994.428～440.［7］李舟军.传值CCS和π-演算中互模拟等价的验证理论与算法[D].长沙：国防科技大学,1999.［8］Lin H. Symbolic transition graph with assignment[A]. CONCUR'96 [C], Lecture Notes in Computer Science 1119,Springer, 1996.50～65.［9］Boreale M, De Nicola R. A symbolic semantis for the π-calculus[J]. Information and Computation, 1996,126:34～52.［10］Pugh W, Bultan T, Gerber R. Symbolic model checking of infinite state systems using Presberger arithmetic [A].CAV'97[C]. Lecture Notes in Computer Science 1254, Springer, 1997.［11］Wolper P, Boigelot B. An automata-theoretic approach to Presburger arithmetic constraints[A]. Proceedings of Static Analysis Symposium[C]. Lecture in Computer Science 983, Springer, 1995.21～32.
Institute of Scientific and Technical Information of China (English)
Deepak KAPUR
2006-01-01
A method using quantifier-elimination is proposed for automatically generating program invariants/inductive assertions. Given a program, inductive assertions, hypothesized as parameterized formulas in a theory, are associated with program locations. Parameters in inductive assertions are discovered by generating constraints on parameters by ensuring that an inductive assertion is indeed preserved by all execution paths leading to the associated location of the program. The method can be used to discover loop invariants-properties of variables that remain invariant at the entry of a loop. The parameterized formula can be successively refined by considering execution paths one by one; heuristics can be developed for determining the order in which the paths are considered. Initialization of program variables as well as the precondition and postcondition, if available, can also be used to further refine the hypothesized invariant. The method does not depend on the availability of the precondition and postcondition of a program. Constraints on parameters generated in this way are solved for possible values of parameters. If no solution is possible, this means that an invariant of the hypothesized form is not likely to exist for the loop under the assumptions/approximations made to generate the associated verification condition. Otherwise, if the parametric constraints are solvable, then under certain conditions on methods for generating these constraints, the strongest possible invariant of the hypothesized form can be generated from most general solutions of the parametric constraints. The approach is illustrated using the logical languages of conjunction of polynomial equations as well as Presburger arithmetic for expressing assertions.
Characterization and robust filtering of multifunctional surfaces using ISO standards
DEFF Research Database (Denmark)
Friis, Kasper Storgaard; Godi, Alessandro; De Chiffre, Leonardo
2011-01-01
to the multi-process production method involved. A series of MUFU surfaces were characterized by using the ISO 13565 standard for stratified surfaces and it is shown that the standard in some cases is inadequate for the characterization of a MUFU surface. To improve the filtering of MUFU surfaces, the robust...... Gaussian regression filtering technique described in ISO 16610-31 is analyzed and discussed. By slight modifications it is shown how the robust Gaussian regression filter can be applied to remove the form and find a suitable reference surface for further characterization of the MUFU surfaces...
MIPS科技宣布对称多处理支持MIPS-Based~（TM） SoC上的Android~（TM）平台
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
日前,MIPS科技宣布其对称多处理（symmetric multiprocessing,SMP）可支持运行在MIPS-Based~（TM）多内核SoC上的Android~（TM）平台。现在,采用MIPS32~（TM）多线程与多处理内核的MIPS授权客户已能够将丰富的网络与多媒体内容带到具有Android平台的智能手机。
Fast Density Inversion Solution for Full Tensor Gravity Gradiometry Data
Hou, Zhenlong; Wei, Xiaohui; Huang, Danian
2016-02-01
We modify the classical preconditioned conjugate gradient method for full tensor gravity gradiometry data. The resulting parallelized algorithm is implemented on a cluster to achieve rapid density inversions for various scenarios, overcoming the problems of computation time and memory requirements caused by too many iterations. The proposed approach is mainly based on parallel programming using the Message Passing Interface, supplemented by Open Multi-Processing. Our implementation is efficient and scalable, enabling its use with large-scale data. We consider two synthetic models and real survey data from Vinton Dome, US, and demonstrate that our solutions are reliable and feasible.
A distributed infrastructure for publishing VO services: an implementation
Cepparo, Francesco; Scagnetto, Ivan; Molinaro, Marco; Smareglia, Riccardo
2016-07-01
This contribution describes both the design and the implementation details of a new solution for publishing VO services, enlightening its maintainable, distributed, modular and scalable architecture. Indeed, the new publisher is multithreaded and multiprocess. Multiple instances of the modules can run on different machines to ensure high performance and high availability, and this will be true both for the interface modules of the services and the back end data access ones. The system uses message passing to let its components communicate through an AMQP message broker that can itself be distributed to provide better scalability and availability.
Tennel, E. P.; Hinze, W. J.
1981-09-01
Total intensity magnetic anomaly data acquired as a supplement to radiometric data in preparing regional profile and contour maps are discussed. Survey contractor supplied magnetic anomaly data are subjected to a multiprocess, computer based procedure. This procedure is used to produce the following machine plotted maps: (1) profile map of contractor supplied magnetic anomaly data; (2) profile map of high cut filtered data with contour levels of each profile marked and annotated on the associated flight track; (3) profile map of critical point data with contour levels indicated; and (4) contour map of filtered and selected data.
Integrated Process Capability Analysis
Institute of Scientific and Technical Information of China (English)
Chen; H; T; Huang; M; L; Hung; Y; H; Chen; K; S
2002-01-01
Process Capability Analysis (PCA) is a powerful too l to assess the ability of a process for manufacturing product that meets specific ations. The larger process capability index implies the higher process yield, a nd the larger process capability index also indicates the lower process expected loss. Chen et al. (2001) has applied indices C pu, C pl, and C pk for evaluating the process capability for a multi-process product wi th smaller-the-better, larger-the-better, and nominal-the-best spec...
Multiscale Analysis and Optimisation of Photosynthetic Solar Energy Systems
Ringsmuth, Andrew K
2014-01-01
This work asks how light harvesting in photosynthetic systems can be optimised for economically scalable, sustainable energy production. Hierarchy theory is introduced as a system-analysis and optimisation tool better able to handle multiscale, multiprocess complexities in photosynthetic energetics compared with standard linear-process analysis. Within this framework, new insights are given into relationships between composition, structure and energetics at the scale of the thylakoid membrane, and also into how components at different scales cooperate under functional objectives of the whole photosynthetic system. Combining these reductionistic and holistic analyses creates a platform for modelling multiscale-optimal, idealised photosynthetic systems in silico.
Environments for online maritime simulators with cloud computing capabilities
Raicu, Gabriel; Raicu, Alexandra
2016-12-01
This paper presents the cloud computing environments, network principles and methods for graphical development in realistic naval simulation, naval robotics and virtual interactions. The aim of this approach is to achieve a good simulation quality in large networked environments using open source solutions designed for educational purposes. Realistic rendering of maritime environments requires near real-time frameworks with enhanced computing capabilities during distance interactions. E-Navigation concepts coupled with the last achievements in virtual and augmented reality will enhance the overall experience leading to new developments and innovations. We have to deal with a multiprocessing situation using advanced technologies and distributed applications using remote ship scenario and automation of ship operations.
Research on Network-based Integrated Condition Monitoring Unit for Rotating Machinery
Institute of Scientific and Technical Information of China (English)
XI Xiao-peng; ZHANG Wen-rui; XI Shuan-min; JING Min-qing; YU Lie
2004-01-01
In this paper, a network-based monitoring unit for condition monitoring and fault diagnosis of rotating machinery is designed and implemented. With the technology of DSP( Digital signal processing), TCP/IP, and simultaneous acquisition, a mechanism of multi-process and inter-process communication, the integrating problem of signal acquisition, the data dynamic management and network-based configuration in the embedded condition monitoring system is solved. It offers the input function of monitoring information for network-based condition monitoring and a fault diagnosis system.
Scheduler for multiprocessor system switch with selective pairing
Energy Technology Data Exchange (ETDEWEB)
Gara, Alan; Gschwind, Michael Karl; Salapura, Valentina
2015-01-06
System, method and computer program product for scheduling threads in a multiprocessing system with selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). The method configures the selective pairing facility to use checking provide one highly reliable thread for high-reliability and allocate threads to corresponding processor cores indicating need for hardware checking. The method configures the selective pairing facility to provide multiple independent cores and allocate threads to corresponding processor cores indicating inherent resilience.
An Analysis and Design of the Virtual Simulation Software Based on Pattern
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The paper makes a detailed analysis and design of the Vega application software based on Windows NT platform. It includes object-oriented software analysis and design, design patterns and Windows kernel mechanism. The paper brings forward a design pattern, a fence-pattern, and depends on this pattern. Windows NT memory mapped files adopted, the paper presents a Vega application solution based on the multi-process technique. Although the design solution is developing under a real-time simulation system, it is established at the clear analysis of the Vega system, therefore, the solution has extensive practicability and many uses.
Simulating futures in extended common LISP
Nachtsheim, Philip R.
1988-01-01
Stack-groups comprise the mechanism underlying implementation of multiprocessing in Extended Common LISP, i.e., running multiple quasi-simultaneous processes within a single LISP address space. On the other hand, the future construct of MULTILISP, an extension of the LISP dialect scheme, deals with parallel execution. The source of concurrency that future exploits is the overlap between computation of a value and use of the value. Described is a simulation of the future construct by an interpreter utilizing stack-group extensions to common LISP.
Security audits of multi-tier virtual infrastructures in public infrastructure clouds
DEFF Research Database (Denmark)
Bleikertz, Sören; Schunter, Matthias; Probst, Christian W.
2010-01-01
Cloud computing has gained remarkable popularity in the recent years by a wide spectrum of consumers, ranging from small start-ups to governments. However, its benefits in terms of flexibility, scalability, and low upfront investments, are shadowed by security challenges which inhibit its adoption...... security configurations. In this article we present a novel approach in the security assessment of the end-user configuration of multi-tier architectures deployed on infrastructure clouds such as Amazon EC2. In order to perform this assessment for the currently deployed configuration, we automated...... the process of extracting the configuration using the Amazon API. In the assessment we focused on the reachability and vulnerability of services in the virtual infrastructure, and presented a way for the visualization and automated analysis based on reachability and attack graphs. We proposed a query...
Synchronization of Arbitrarily Switched Boolean Networks.
Chen, Hongwei; Liang, Jinling; Huang, Tingwen; Cao, Jinde
2017-03-01
This paper investigates the complete synchronization problem for the drive-response switched Boolean networks (SBNs) under arbitrary switching signals, where the switching signals of the response SBN follow those generated by the drive SBN at each time instant. First, the definition of complete synchronization is introduced for the drive-response SBNs under arbitrary switching signals. Second, the concept of switching reachable set starting from a given initial state set is put forward. Based on it, a necessary and sufficient condition is derived for the complete synchronization of the drive-response SBNs. Last, we give a simple algebraic expression for the switching reachable set in a given number of time steps, and two computable algebraic criteria are obtained for the complete synchronization of the SBNs. A biological example is given to demonstrate the effectiveness of the obtained main results.
Finitely approximable random sets and their evolution via differential equations
Ananyev, B. I.
2016-12-01
In this paper, random closed sets (RCS) in Euclidean space are considered along with their distributions and approximation. Distributions of RCS may be used for the calculation of expectation and other characteristics. Reachable sets on initial data and some ways of their approximate evolutionary description are investigated for stochastic differential equations (SDE) with initial state in some RCS. Markov property of random reachable sets is proved in the space of closed sets. For approximate calculus, the initial RCS is replaced by a finite set on the integer multidimensional grid and the multistage Markov chain is substituted for SDE. The Markov chain is constructed by methods of SDE numerical integration. Some examples are also given.
Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro
2017-01-01
The development of lithography processes with sub-10 nm resolution is challenging. Stochastic phenomena such as line width roughness (LWR) are significant problems. In this study, the feasibility of sub-10 nm fabrication using chemically amplified extreme ultraviolet resists with photodecomposable quenchers was investigated from the viewpoint of the suppression of LWR. The relationship between sensitizer concentration (the sum of acid generator and photodecomposable quencher concentrations) and resist performance was clarified, using the simulation based on the sensitization and reaction mechanisms of chemically amplified resists. For the total sensitizer concentration of 0.5 nm-3 and the effective reaction radius for the deprotection of 0.1 nm, the reachable half-pitch while maintaining 10% critical dimension (CD) LWR was 11 nm. The reachable half-pitch was 7 nm for 20% CD LWR. The increase in the effective reaction radius is required to realize the sub-10 nm fabrication with 10% CD LWR.
Aschepkov, Leonid T; Kim, Taekyun; Agarwal, Ravi P
2016-01-01
This book is based on lectures from a one-year course at the Far Eastern Federal University (Vladivostok, Russia) as well as on workshops on optimal control offered to students at various mathematical departments at the university level. The main themes of the theory of linear and nonlinear systems are considered, including the basic problem of establishing the necessary and sufficient conditions of optimal processes. In the first part of the course, the theory of linear control systems is constructed on the basis of the separation theorem and the concept of a reachability set. The authors prove the closure of a reachability set in the class of piecewise continuous controls, and the problems of controllability, observability, identification, performance and terminal control are also considered. The second part of the course is devoted to nonlinear control systems. Using the method of variations and the Lagrange multipliers rule of nonlinear problems, the authors prove the Pontryagin maximum principle for prob...
Dynamic Programming and Error Estimates for Stochastic Control Problems with Maximum Cost
Energy Technology Data Exchange (ETDEWEB)
Bokanowski, Olivier, E-mail: boka@math.jussieu.fr [Laboratoire Jacques-Louis Lions, Université Paris-Diderot (Paris 7) UFR de Mathématiques - Bât. Sophie Germain (France); Picarelli, Athena, E-mail: athena.picarelli@inria.fr [Projet Commands, INRIA Saclay & ENSTA ParisTech (France); Zidani, Hasnaa, E-mail: hasnaa.zidani@ensta.fr [Unité de Mathématiques appliquées (UMA), ENSTA ParisTech (France)
2015-02-15
This work is concerned with stochastic optimal control for a running maximum cost. A direct approach based on dynamic programming techniques is studied leading to the characterization of the value function as the unique viscosity solution of a second order Hamilton–Jacobi–Bellman (HJB) equation with an oblique derivative boundary condition. A general numerical scheme is proposed and a convergence result is provided. Error estimates are obtained for the semi-Lagrangian scheme. These results can apply to the case of lookback options in finance. Moreover, optimal control problems with maximum cost arise in the characterization of the reachable sets for a system of controlled stochastic differential equations. Some numerical simulations on examples of reachable analysis are included to illustrate our approach.
Rewriting Modulo SMT and Open System Analysis
Rocha, Camilo; Meseguer, Jose; Munoz, Cesar
2014-01-01
This paper proposes rewriting modulo SMT, a new technique that combines the power of SMT solving, rewriting modulo theories, and model checking. Rewriting modulo SMT is ideally suited to model and analyze infinite-state open systems, i.e., systems that interact with a non-deterministic environment. Such systems exhibit both internal non-determinism, which is proper to the system, and external non-determinism, which is due to the environment. In a reflective formalism, such as rewriting logic, rewriting modulo SMT can be reduced to standard rewriting. Hence, rewriting modulo SMT naturally extends rewriting-based reachability analysis techniques, which are available for closed systems, to open systems. The proposed technique is illustrated with the formal analysis of: (i) a real-time system that is beyond the scope of timed-automata methods and (ii) automatic detection of reachability violations in a synchronous language developed to support autonomous spacecraft operations.
Cross gramian approximation with Laguerre polynomials for model order reduction
Perev, Kamen
2015-11-01
This paper considers the problem of model order reduction by approximate balanced truncation with Laguerre polynomials approximation of the system cross gramian. The cross gramian contains information both for the reachability of the system as well as for its observability. The main property of the cross gramian for a square symmetric stable linear system is that its square is equal to the product of the reachability and observability gramians and therefore, the absolute values of its eigenvalues are equal to the Hankel singular values. This is the reason to use the cross gramian for computing balancing transformations for model reduction. Laguerre polynomial series representations are used to approximate the cross gramian of the system at infinity. The orthogonal polynomials of Laguerre possess good convergence properties and allow to reduce the computational complexity of the model reduction problem. Numerical experiments are performed confirming the effectiveness of the proposed method.
CONTROLLABILITY OF DELAY DEGENERATE CONTROL SYSTEMS WITH INDEPENDENT SUBSYSTEMS
Institute of Scientific and Technical Information of China (English)
蒋威
2003-01-01
The controllability of delay degenerate differential control systems is discussed. Firstly, delay degenerate differential control system was transformed to be canonical form, and the connected terms were gotten rid of, had delay degenerate differential control systems with independent subsystems. For the general delay degenerate differnetial control systems, it was gotten that the necessary and sufficient condition of that they are controllable is that their reachable set is equal to the whole space For the delay degenerate differential control systems with independent subsystems, it was gotten that the necessary and sufficient conditions of that they are controllable are that their reachable sets are equal to their corresponding subspaces. Then some algebra criteria were gotten. Finally, an example was given to illustrate the main results.
Review paper of gateway selection schemes for MANET of NEMO (MANEMO)
Mahmood, Z.; Hashim, A.; Khalifa, O.; Anwar, F.; Hameed, S.
2013-12-01
The fast growth of Internet applications brings with it new challenges for researchers to provide new solutions that guarantee better Internet access for mobile hosts and networks. The globally reachable, Home-Agent based, infrastructure Network Mobility (NEMO) and the local, multi-hop, and infrastructure-less Mobile Ad hoc Network (MANET) developed by Internet Engineering Task Force (IETF) support different topologies of the mobile networks. A new architecture was proposed by combining both topologies to obtain Mobile Ad Hoc NEMO (MANEMO). However, the integration of NEMO and MANET introduces many challenges such as network loops, sub-optimal route, redundant tunnel problem, absence of communication without Home Agent reachability, and exit router selection when multiple Exit Routers to the Internet exist. This paper aims to review the different proposed models that could be used to implement the gateway selection mechanism and it highlights the strengths as well as the limitations of these approaches.
Security audits of multi-tier virtual infrastructures in public infrastructure clouds
DEFF Research Database (Denmark)
Bleikertz, Sören; Schunter, Matthias; Probst, Christian W.
2010-01-01
Cloud computing has gained remarkable popularity in the recent years by a wide spectrum of consumers, ranging from small start-ups to governments. However, its benefits in terms of flexibility, scalability, and low upfront investments, are shadowed by security challenges which inhibit its adoption....... Managed through a web-services interface, users can configure highly flexible but complex cloud computing environments. Furthermore, users misconfiguring such cloud services poses a severe security risk that can lead to security incidents, e.g., erroneous exposure of services due to faulty network...... the process of extracting the configuration using the Amazon API. In the assessment we focused on the reachability and vulnerability of services in the virtual infrastructure, and presented a way for the visualization and automated analysis based on reachability and attack graphs. We proposed a query...
Finite Countermodel Based Verification for Program Transformation (A Case Study
Directory of Open Access Journals (Sweden)
Alexei P. Lisitsa
2015-12-01
Full Text Available Both automatic program verification and program transformation are based on program analysis. In the past decade a number of approaches using various automatic general-purpose program transformation techniques (partial deduction, specialization, supercompilation for verification of unreachability properties of computing systems were introduced and demonstrated. On the other hand, the semantics based unfold-fold program transformation methods pose themselves diverse kinds of reachability tasks and try to solve them, aiming at improving the semantics tree of the program being transformed. That means some general-purpose verification methods may be used for strengthening program transformation techniques. This paper considers the question how finite countermodels for safety verification method might be used in Turchin's supercompilation method. We extract a number of supercompilation sub-algorithms trying to solve reachability problems and demonstrate use of an external countermodel finder for solving some of the problems.
Effective number of accessed nodes in complex networks.
Viana, Matheus P; Batista, João L B; Costa, Luciano da F
2012-03-01
The measurement called accessibility has been proposed as a means to quantify the efficiency of the communication between nodes in complex networks. This article reports results regarding the properties of accessibility, including its relationship with the average minimal time to visit all nodes reachable after h steps along a random walk starting from a source, as well as the number of nodes that are visited after a finite period of time. We characterize the relationship between accessibility and the average number of walks required in order to visit all reachable nodes (the exploration time), conjecture that the maximum accessibility implies the minimal exploration time, and confirm the relationship between the accessibility values and the number of nodes visited after a basic time unit. The latter relationship is investigated with respect to three types of dynamics: traditional random walks, self-avoiding random walks, and preferential random walks.
Strategy Improvement for Concurrent Safety Games
Chatterjee, Krishnendu; Henzinger, Thomas A
2008-01-01
We consider concurrent games played on graphs. At every round of the game, each player simultaneously and independently selects a move; the moves jointly determine the transition to a successor state. Two basic objectives are the safety objective: ``stay forever in a set F of states'', and its dual, the reachability objective, ``reach a set R of states''. We present in this paper a strategy improvement algorithm for computing the value of a concurrent safety game, that is, the maximal probability with which player 1 can enforce the safety objective. The algorithm yields a sequence of player-1 strategies which ensure probabilities of winning that converge monotonically to the value of the safety game. The significance of the result is twofold. First, while strategy improvement algorithms were known for Markov decision processes and turn-based games, as well as for concurrent reachability games, this is the first strategy improvement algorithm for concurrent safety games. Second, and most importantly, the impro...
Design of a plasma discharge circuit for particle wakefield acceleration
Anania, M P; Cianchi, A; Di Giovenale, D; Ferrario, M; Flora, F; Gallerano, G P; Ghigo, A; Marocchino, A; Massimo, F; Mostacci, A; Mezi, L; Musumeci, P; Serio, M; 10.1016/j.nima.2013.10.053
2014-01-01
Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV m^-1), enabling acceleration of electrons to GeV energy in few centimetres. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators; radiofrequency-based accelerators, in fact, are limited in the accelerating field (10-100 MV m^-1) requiring therefore kilometric distances to reach the GeV energies, but can provide very bright electron bunches. Combining high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of shor...
Schedulability Analysis Method of Timing Constraint Petri Nets
Institute of Scientific and Technical Information of China (English)
李慧芳; 范玉顺
2002-01-01
Timing constraint Petri nets (TCPNs) can be used to model a real-time system specification and to verify the timing behavior of the system. This paper describes the limitations of the reachability analysis method in analyzing complex systems for existing TCPNs. Based on further research on the schedulability analysis method with various topology structures, a more general state reachability analysis method is proposed. To meet various requirements of timely response for actual systems, this paper puts forward a heuristic method for selecting decision-spans of transitions and develops a heuristic algorithm for schedulability analysis of TCPNs. Examples are given showing the practicality of the method in the schedulability analysis for real-time systems with various structures.
Controllability and Observability Criteria for Linear Piecewise Constant Impulsive Systems
Directory of Open Access Journals (Sweden)
Hong Shi
2012-01-01
Full Text Available Impulsive differential systems are an important class of mathematical models for many practical systems in physics, chemistry, biology, engineering, and information science that exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynamical processes. This paper studies the controllability and observability of linear piecewise constant impulsive systems. Necessary and sufficient criteria for reachability and controllability are established, respectively. It is proved that the reachability is equivalent to the controllability under some mild conditions. Then, necessary and sufficient criteria for observability and determinability of such systems are established, respectively. It is also proved that the observability is equivalent to the determinability under some mild conditions. Our criteria are of the geometric type, and they can be transformed into algebraic type conveniently. Finally, a numerical example is given to illustrate the utility of our criteria.
Termination of Nondeterministic Quantum Programs
Li, Yangjia; Ying, Mingsheng
2012-01-01
We define a language-independent model of nondeterministic quantum programs in which a quantum program consists of a finite set of quantum processes. These processes are represented by quantum Markov chains over the common state space. An execution of a nondeterministic quantum program is modeled by a sequence of actions of individual processes. These actions are described by super-operators on the state Hilbert space. At each step of an execution, a process is chosen nondeterministically to perform the next action. A characterization of reachable space and a characterization of diverging states of a nondeterministic quantum program are presented. We establish a zero-one law for termination probability of the states in the reachable space of a nondeterministic quantum program. A combination of these results leads to a necessary and sufficient condition for termination of nondeterministic quantum programs. Based on this condition, an algorithm is found for checking termination of nondeterministic quantum progr...
Supervisory control based on minimal cuts and Petri net sub-controllers coordination
Rezig, Sadok; Achour, Zied; Rezg, Nidhal; Kammoun, Mohamed-Ali
2016-10-01
This paper addresses the synthesis of Petri net (PN) controller for the forbidden state transition problem with a new utilisation of the theory of regions. Moreover, as any method of control synthesis based on a reachability graph, the theory of regions suffers from the combinatorial explosion problem. The proposed work minimises the number of equations in the linear system of theory of regions and therefore one can reduce the computation time. In this paper, two different approaches are proposed to select minimal cuts in the reachability graph in order to synthesise a PN controller. Thanks to a switch from one cut to another, one can activate and deactivate the corresponding PNcontroller. An application is implemented in a flexible manufacturing system to illustrate the present method. Finally, comparison with previous works with experimental results in obtaining a maximally permissive controller is presented.
Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing
Kitsak, Maksim; Havlin, Shlomo; Krioukov, Dmitri
2015-01-01
Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems. Due to privacy and other reasons the information about what route to use to reach devices within other Autonomous Systems is not readily available to any given Autonomous System. The Border Gateway Protocol is responsible for discovering and distributing this reachability information to all Autonomous Systems. Since the topology of the Internet is highly dynamic, all Autonomous Systems constantly exchange and update this reachability information in small chunks, known as routing control packets or Border Gateway Protocol updates. Motivated by scalability and predictability issues with the dynamics of these updates in the quickly growing Internet, we conduct a systematic time series analysis of Border Gateway Protocol update rates. We find that Border Gateway Protocol update time series are extremely volatile, exhibit long-term correlations a...
Protect the Secrecy in Password-Based Key Exchange Protocols
Institute of Scientific and Technical Information of China (English)
LILi; SUNHaibo; XUERui; ZHANGHuanguo
2005-01-01
This paper proposes a new model called term-node graph, which is a formal method based on Dolev-Yao model[15], to analyze this problem. In this framework, each node is a term of message exchang ingin the protocol and each edge denotes a relation between terms. Essentially, properties of security protocols are all relative to secrets. Based on this thought, term-node graph model emphasizes the relation between terms and then secrecy can come down to the problem of reachability of terms through some reachable paths. We conclude a generic form of three party password-only key exchange protocols. Applying this model to analyze the secrecy of the generic protoco4 a general necessary condition is deduced on the security of the three party password-only key exchange protocols: To resist the guessing attack on pass-words, the number of message-exchange steps among the three parties should be more than five.
Sequentializing Parameterized Programs
Directory of Open Access Journals (Sweden)
Salvatore La Torre
2012-07-01
Full Text Available We exhibit assertion-preserving (reachability preserving transformations from parameterized concurrent shared-memory programs, under a k-round scheduling of processes, to sequential programs. The salient feature of the sequential program is that it tracks the local variables of only one thread at any point, and uses only O(k copies of shared variables (it does not use extra counters, not even one counter to keep track of the number of threads. Sequentialization is achieved using the concept of a linear interface that captures the effect an unbounded block of processes have on the shared state in a k-round schedule. Our transformation utilizes linear interfaces to sequentialize the program, and to ensure the sequential program explores only reachable states and preserves local invariants.
Shadow-Bitcoin: Scalable Simulation via Direct Execution of Multi-Threaded Applications
2015-08-10
getaddr.bitnodes.io/, which performs daily crawls of the net- work, recent versions of Satoshi accounts for 83% of the reachable nodes. BitcoinJ is likely...models do not account for the ob- served network structure [33]. However, we stress that our primary goal is to demonstrate the flexibility we have in...precisely model the real network. Providing initial blockchain state. Each node in the Bitcoin network typically maintains its own copy of the entire
Swei, Sean
2014-01-01
We propose to develop a robust guidance and control system for the ADEPT (Adaptable Deployable Entry and Placement Technology) entry vehicle. A control-centric model of ADEPT will be developed to quantify the performance of candidate guidance and control architectures for both aerocapture and precision landing missions. The evaluation will be based on recent breakthroughs in constrained controllability/reachability analysis of control systems and constrained-based energy-minimum trajectory optimization for guidance development operating in complex environments.
Abstract Acceleration of General Linear Loops
2014-01-01
International audience; We present abstract acceleration techniques for computing loop invariants for numerical programs with linear assignments and conditionals. Whereas abstract interpretation techniques typically over-approximate the set of reachable states iteratively, abstract acceleration captures the effect of the loop with a single, non-iterative transfer function applied to the initial states at the loop head. In contrast to previous acceleration techniques, our approach applies to a...
Viability decision of linear discrete-time stochastic systems with probability criterion
Institute of Scientific and Technical Information of China (English)
Wansheng TANG; Jun ZHENG; Jianxiong ZHANG
2009-01-01
In this paper,the optimal viability decision problem of linear discrete-time stochastic systems with probability criterion is investigated.Under the condition of sequence-reachable discrete-time dynamic systems,the existence theorem of optimal viability strategy is given and the solving procedure of the optimal strategy is provided based on dynamic programming.A numerical example shows the effectiveness of the proposed methods.
Performance of BGP Among Mobile Military Networks
2011-04-08
widely used policy-based routing protocol to date. Explicit MANET routing protocols (e.g., AODV , DSR, LAR [3]) are not con- sidered policy-based... routes to destinations (e.g., reachability), and its influence on network’s outage events. Furthermore, our modified BGP protocol is compared to the OSPF...and OSPF-MDR routing protocols for mobile networks with increasing number of nodes. Our results show that modified BGP’s overhead growth is
Analysis of Linear Hybrid Systems in CLP
DEFF Research Database (Denmark)
Banda, Gourinath; Gallagher, John Patrick
2009-01-01
notation for specifying real-time systems. The main contributions are (i) a technique for capturing the reachable states of the continuously changing state variables of the LHA as CLP constraints; (ii) a way of representing events in the LHA as constraints in CLP, along with a product construction...... and argue that we contribute to the general field of using static analysis tools for verification...
A Model for Industrial Real-Time Systems
DEFF Research Database (Denmark)
Bin Waez, Md Tawhid; Wasowski, Andrzej; Dingel, Juergen
2015-01-01
Introducing automated formal methods for large industrial real-time systems is an important research challenge. We propose timed process automata (TPA) for modeling and analysis of time-critical systems which can be open, hierarchical, and dynamic. The model offers two essential features for larg...... establish safety and reachability properties of TPA by reduction to solving timed games. To mitigate the state-space explosion problem, an automated state-space reduction technique using compositional reasoning and aggressive abstractions is also proposed....
Solving Simple Stochastic Games with Few Random Vertices
Gimbert, Hugo; Horn, Florian
2007-01-01
Simple stochastic games are two-player zero-sum stochastic games with turn-based moves, perfect information, and reachability winning conditions. We present two new algorithms computing the values of simple stochastic games. Both of them rely on the existence of optimal permutation strategies, a class of positional strategies derived from permutations of the random vertices. The "permutation-enumeration" algorithm performs an exhaustive search among these strategies, while the "permutation-im...
Numerical methods for control optimization in linear systems
Tyatyushkin, A. I.
2015-05-01
Numerical methods are considered for solving optimal control problems in linear systems, namely, terminal control problems with control and phase constraints and time-optimal control problems. Several algorithms with various computer storage requirements are proposed for solving these problems. The algorithms are intended for finding an optimal control in linear systems having certain features, for example, when the reachable set of a system has flat faces.
Directory of Open Access Journals (Sweden)
V. A. Sokolov
2015-01-01
Full Text Available This article describes the organization principles for wireless mesh-networks (software-deﬁned net-works of mobile objects. The emphasis is on the questions of getting eﬀective routing algorithms for such networks. The mathematical model of the system is the standard transportation network. The key parameter of the routing system is the node reachability coeﬃcient — the function depending on several basic and additional parameters (“mesh-factors”, which characterize the route between two network nodes. Each pair (arc, node is juxtaposed to a composite parameter which characterizes the “reacha-bility” of the node by the route which begins with this arc. The best (“shortest” route between two nodes is the route with the maximum reachability coeﬃcient. The rules of building and refreshing the routing tables by the network nodes are described. With the announcement from the neighbor the node gets the information about the connection energy and reliability, the announcement time of receipt, the absence of transitional nodes and also about the connection capability. On the basis of this informationthe node applies the penalization (decreasing the reachability coeﬃcient or the reward (increasing the reachability coeﬃcient to all routes through this neighbor node. The penalization / reward scheme has some separate aspects: 1. Penalization for the actuality of information. 2. Penalization / reward for the reliability of a node. 3. Penalization for the connection energy. 4. Penalization for the present connection capability. The simulator of the wireless mesh-network of mobile objects is written. It is based on the suggested heuristic algorithms. The description and characteristics of the simulator are stated in the article. The peculiarities of its program realization are also examined.
Properties of Distributed Timed-Arc Petri Nets
DEFF Research Database (Denmark)
Nielsen, M.; Sassone, V.; Srba, J.
2001-01-01
In [12] we started a research on a distributed-timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. This formalism enables to model e.g. hardware architectures like GALS. We give a formal de...... definition of process semantics for our model and investigate several properties of local versus global timing: expressiveness, reachability and coverability....
A development calculus for specifications
Institute of Scientific and Technical Information of China (English)
李未
2003-01-01
A first order inference system, named R-calculus, is defined to develop the specifications.This system intends to eliminate the laws which are not consistent with users' requirements. TheR-calculus consists of the structural rules, an axiom, a cut rule, and the rules for logical connectives.Some examples are given to demonstrate the usage of the R-calculus. Furthermore, the propertiesregarding reachability and completeness of the R-calculus are formally defined and proved.
A Principled Approach to Managing Routing in Large ISP Networks
2009-06-01
internal routing protocol (“Interior Gateway Protocol”, or IGP ) to disseminate reachability information about destinations within its network. Together... IGP and BGP ensure an internal router of an AS knows how to send traffic first to an edge router of the network (via an IGP path), in order to reach...tice to first reconfigure the IGP in the network (e.g., increase the weights of the links adjacent to the router to make them less attractive) in order
Analysing Decisive Stochastic Processes
Bertrand, Nathalie; Bouyer, Patricia; Brihaye, Thomas; Carlier, Pierre,
2016-01-01
International audience; In 2007, Abdulla et al. introduced the elegant concept of decisive Markov chain. Intuitively, de-cisiveness allows one to lift the good properties of finite Markov chains to infinite Markov chains. For instance, the approximate quantitative reachability problem can be solved for decisive Markov chains (enjoying reasonable effectiveness assumptions) including probabilistic lossy channel systems and probabilistic vector addition systems with states. In this paper, we ext...
Maintenance of the CERN telephone exchanges
TS Department
2008-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and midnight on 3 December. During this time, the fixed-line telephone and audio-conference services may be disrupted. However, the CCC and the Fire Brigade will be reachable at all times. Mobile telephone services (GSM) will not be affected by this work. For further details please contact Netops@cern.ch.
Maintenance of the CERN telephone exchanges
IT Department
2011-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 20h00 and 2h00 on the 16 November. Fixed-line telephone and audio-conference services may be disrupted during this intervention. Nevertheless, the CCC and the fire brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work. IT/CS
Maintenance of the CERN telephone exchanges
2007-01-01
Maintenance work on the CERN telephone exchanges will be performed on 10 July from 8 p.m. to midnight. During this intervention, the fixed telephone services, audioconference services and GSM calls made via the 333 prefix may be disrupted. However, the CCC and the fire brigade will be reachable at all times. For more details about this maintenance work, please call the telephone switchboard on 76111 or send an e-mail. Telecom SectionIT/CS
Maintenance of the CERN telephone exchanges
2007-01-01
A maintenance of the CERN telephone exchanges will be performed on the 10th of July from 8 p.m. to midnight. During this intervention, the fixed telephone services, audioconference services, and GSM calls made via the 333 prefix may be disrupted. However, the CCC and the fire brigade will be reachable at any time. For more details about this maintenance, please contact the telephone switchboard at 76111 or by email. Telecom Section IT/CS
Maintenance of the CERN telephone exchanges
IT Department
2011-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 20h00 and midnight on the 21st of February in order to apply the latest software patches. Fixed-line telephone and audio-conference services may be disrupted during this intervention. Nevertheless, the CCC and the fire brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work. CS Group
Maintenance of the CERN telephone exchanges
TS Department
2008-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and midnight on 3 December. During this time, the fixed-line telephone and audio-conference services may be disrupted. However, the CCC and the Fire Brigade will be reachable at all times. Mobile telephone services (GSM) will not be affected by this work. For further details please contact mailto:Netops@cern.ch.
Maintenance of the CERN telephone exchanges
IT Department
2009-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 8h30 and 17h30 on Saturday 9 May. Fixed-line telephone and audio-conference services may be disrupted during this intervention. Nevertheless, the CCC and the fire brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work. IT/CS/CS
Maintenance of the CERN telephone exchanges
IT Department
2009-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 20h00 and midnight on the 29th of July in order to apply the latest software patches. Fixed-line telephone and audio-conference services may be disrupted during this intervention. Nevertheless, the CCC and the fire brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work. IT/CS/CS
Directory of Open Access Journals (Sweden)
Kaczorek Tadeusz
2016-06-01
Full Text Available The minimum energy control problem for the descriptor discrete-time linear systems by the use of Weierstrass-Kronecker decomposition is formulated and solved. Necessary and sufficient conditions for the reachability of descriptor discrete-time linear systems are given. A procedure for computation of optimal input and a minimal value of the performance index is proposed and illustrated by a numerical example.
The perception of peripersonal space in right and left brain damage hemiplegic patients.
Bartolo, Angela; Carlier, Mauraine; Hassaini, Sabrina; Martin, Yves; Coello, Yann
2014-01-01
Peripersonal space, as opposed to extrapersonal space, is the space that contains reachable objects and in which multisensory and sensorimotor integration is enhanced. Thus, the perception of peripersonal space requires combining information on the spatial properties of the environment with information on the current capacity to act. In support of this, recent studies have provided converging evidences that perceiving objects in peripersonal space activates a neural network overlapping with that subtending voluntary motor action and motor imagery. Other studies have also underlined the dominant role of the right hemisphere (RH) in motor planning and of the left hemisphere (LH) in on-line motor guiding, respectively. In the present study, we investigated the effect of a right or left hemiplegia in the perception of peripersonal space. 16 hemiplegic patients with brain damage to the left (LH) or right (RH) hemisphere and eight matched healthy controls performed a color discrimination, a motor imagery and a reachability judgment task. Analyses of response times and accuracy revealed no variation among the three groups in the color discrimination task, suggesting the absence of any specific perceptual or decisional deficits in the patient groups. In contrast, the patient groups revealed longer response times in the motor imagery task when performed in reference to the hemiplegic arm (RH and LH) or to the healthy arm (RH). Moreover, RH group showed longer response times in the reachability judgment task, but only for stimuli located at the boundary of peripersonal space, which was furthermore significantly reduced in size. Considered together, these results confirm the crucial role of the motor system in motor imagery task and the perception of peripersonal space. They also revealed that RH damage has a more detrimental effect on reachability estimates, suggesting that motor planning processes contribute specifically to the perception of peripersonal space.
Findability och informationskompetens vid webbnavigation
DEFF Research Database (Denmark)
Fransson, Jonas
2011-01-01
The article discusses the relationship between users, information objects, information systems and the Web, combined with the concepts findability and information literacy. An important aspect in all information literacy definitions is the ability to effectively gain access to the information...... are identified: the object's characteristics, accessibility, internal navigation, internal search, reachability and web prestige. Both information literacy and findability are defined as query independent aspects of the search, working on a structural level....
Adaptive Sample Bias for Rapidly-exploring Random Trees with Applications to Test Generation
2005-06-01
Lecture Notes in Computer Science , pages 130–144. Springer Verlag, 2000. [2] E...Asarin, T. Dang, and O. Maler. The d/dt tool for verification of hybrid systems. In Computer Aided Verification, volume 2404 of Lecture Notes in Computer Science , pages...Incremental search methods for reachability analysis of continuous and hybrid systems. In HSCC, volume 2993 of Lecture Notes in Computer Science , pages
The Decidability Frontier for Probabilistic Automata on Infinite Words
Chatterjee, Krishnendu; Tracol, Mathieu
2011-01-01
We consider probabilistic automata on infinite words with acceptance defined by safety, reachability, B\\"uchi, coB\\"uchi, and limit-average conditions. We consider quantitative and qualitative decision problems. We present extensions and adaptations of proofs for probabilistic finite automata and present a complete characterization of the decidability and undecidability frontier of the quantitative and qualitative decision problems for probabilistic automata on infinite words.
Quantitative Information Flow as Safety and Liveness Hyperproperties
Directory of Open Access Journals (Sweden)
Hirotoshi Yasuoka
2012-07-01
Full Text Available We employ Clarkson and Schneider's "hyperproperties" to classify various verification problems of quantitative information flow. The results of this paper unify and extend the previous results on the hardness of checking and inferring quantitative information flow. In particular, we identify a subclass of liveness hyperproperties, which we call "k-observable hyperproperties", that can be checked relative to a reachability oracle via self composition.
Workshop on Scientific Analysis and Policy in Network Security
2010-09-10
business process. The input elements which we need comprise. (1) a process model given in a notation such as EPC, BPEL, YAWL or BPMN that contains...with tool support, an appropriate formal representation has to be chosen because semi-formal lan- guages such as BPMN allow to create models with...formal semantics here such as the approaches in [2] for BPMN or [1] for EPC that allow for computation of possible system’s behaviour. Reachability
Model Driven Integrated Decision-Making in Manufacturing Enterprises
Weston, Richard H.
2012-01-01
Decision making requirements and solutions are observed in four world class Manufacturing Enterprises (MEs). Observations made focus on deployed methods of complexity handling that facilitate multi-purpose, distributed decision making. Also observed are examples of partially deficient “integrated decision making” which stem from lack of understanding about how ME structural relations enable and/or constrain reachable ME behaviours. To begin to address this deficiency the paper outlines the us...
Resource-Optimal Scheduling Using Priced Timed Automata
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Rasmussen, Jacob Illum; Subramani, K.
2004-01-01
In this paper, we show how the simple structure of the linear programs encountered during symbolic minimum-cost reachability analysis of priced timed automata can be exploited in order to substantially improve the performance of the current algorithm. The idea is rooted in duality of linear progr......-80 percent performance gain. As a main application area, we show how to solve energy-optimal task graph scheduling problems using the framework of priced timed automata....
The perception of peripersonal space in right and left brain damage hemiplegic patients
Directory of Open Access Journals (Sweden)
Angela eBartolo
2014-01-01
Full Text Available Peripersonal space, as opposed to extrapersonal space, is the space that contains reachable objects and in which multisensory and sensorimotor integration is enhanced. Thus, the perception of peripersonal space requires combining information on the spatial properties of the environment with information on the current capacity to act. In support of this, recent studies have provided converging evidences that perceiving objects in peripersonal space activates a neural network overlapping with that subtending voluntary motor action and motor imagery. Other studies have also underlined the dominant role of the right hemisphere in motor planning and of the left hemisphere in on-line motor guiding, respectively. In the present study, we investigated the effect of a right or left hemiplegia in the perception of peripersonal space. 16 hemiplegic patients with brain damage to the left (LH or right (RH hemisphere and 8 matched healthy controls (HC performed a colour discrimination, a motor imagery and a reachability judgment task. Analyses of response times and accuracy revealed no variation among the three groups in the colour discrimination task, suggesting the absence of any specific perceptual or decisional deficits in the patient groups. In contrast, the patient groups revealed longer response times in the motor imagery task when performed in reference to the hemiplegic arm (RH and LH or to the healthy arm (RH. Moreover, RH group showed longer response times in the reachability judgement task, but only for stimuli located at the boundary of peripersonal space, which was furthermore significantly reduced in size. Considered together, these results confirm the crucial role of the motor system in motor imagery task and the perception of peripersonal space. They also revealed that right hemisphere damage has a more detrimental effect on reachability estimates, suggesting that motor planning processes contribute specifically to the perception of
Features of Traction Transformer Windings Utilised as Inductances
Directory of Open Access Journals (Sweden)
Jiri Danzer
2004-01-01
Full Text Available The paper analyses features of traction transformer desing. Secondary windings of the transformer are utilized as a choke of an locomotive input filter at DC supplying system. Different ways of connections of the secondary windings coils are compared, reachable inductances are determined and forces affecting the coils are computed. The analysis is performed by FEM method for differend locomotive operating modes including breakdown service.
2016-05-01
Algorithm for Overcoming the Curse of Dimensionality for Certain Non-convex Hamilton-Jacobi Equations, Projections and Differential Games Yat Tin...complexity of the resulting algorithm is polynomial in the problem dimension; hence, it overcomes the curse of dimensionality [1, 2]. We extend previous work...compute the evolution of geometric objects [25], which was first used for reachability problems in [21, 22] to our knowledge . Numerical solutions to HJ PDE
Funnel Libraries for Real-Time Robust Feedback Motion Planning
2016-07-21
environments. To our knowledge , the resulting hardware demonstrations on a fixed-wing airplane constitute one of the first examples of provably safe and robust... knowledge , the resulting hardware demonstrations on a fixed-wing airplane constitute one of the first examples of provably safe and robust control for...techniques for computing reachable sets based on the HJB equation have historically suffered from the curse of dimensionality since they rely on
Chase: Control of Heterogeneous Autonomous Sensors for Situational Awareness
2016-08-03
advances in addressing the curse of dimen- sionality in reachability analysis . . . . . . . . . . . . . . 17 4.1.2 Practical applications in multi...the six years of the project. There have now appeared in the peer-reviewed literature nearly 170 papers ac- knowledging support from this award...diligent caretaker of resources in their pursuit of knowledge . We have been extraordinarily lucky to find ourselves in the charge of this selfless
The WSTIAC Quarterly. Volume 9, Number 2, 2009
2009-01-01
but penalizes efficiency. The higher values of Ns lead to rotational speeds that may not be reachable ( rotordynamic and bearing problems), and a lower...integrally linked to the rotordynamics . The bearing system must supply adequate load capacity, plus appropriate stiff- ness and damping, to ensure that the...Just as bearings are coupled to the rotordynamic performance of turbomachines, the seals are coupled to the aerodynamic per- formance of the same
Maintenance of the CERN telephone exchanges
IT/CS
2014-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and 2 a.m. on 26 August. Fixed-line telephone and audio-conference services may be disrupted during this intervention. Nevertheless, the CCC and the Fire Brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work.
Interactive state-space analysis of concurrent systems
Energy Technology Data Exchange (ETDEWEB)
Morgan, E.T.; Razouk, R.R.
1987-10-01
The introduction of concurrency into programs has added to the complexity of the software design process. This is most evident in the design of communications protocols where concurrency is inherent to the behavior of the system. The complexity exhibited by such software systems makes more evident the need for computer-aided tools for automatically analyzing behavior. The Distributed Systems project at UCI has been developing techniques and tools, based on Petri nets, which support the design and evaluation of concurrent software systems. Techniques based on constructing reachability graphs that represent projections and selections of complete state-spaces have been developed. This paper focuses attention on the computer-aided analysis of these graphs for the purpose of proving correctness of the modeled system. The application of the analysis technique to evaluating simulation results for correctness is discussed. The tool which supports this analysis (the reachability graph analyzer, RGA) is also described. This tool provides mechanisms for proving general system properties (e.g., deadlock-freeness) as well as system-specific properties. The tool is sufficiently general to allow a user to apply complex user-defined analysis algorithms to reachability graphs. The alternating-bit protocol, with a bounded channel, is used to demonstrate the power of the tool and to point to future extensions.
On the polynomial dynamic system approach to software development
Institute of Scientific and Technical Information of China (English)
WANG Xiangyun; LI Yongchao; CAI Kaiyuan
2004-01-01
In this paper the development of reactive software is transformed into a control problem, and the supervisory control theory for discrete event dynamic systems is suggested to solve this control problem. The operating environment under consideration is viewed as a controlled plant, the software under development as the corresponding controller, and the software requirements as the corresponding control objective. This idea leads to a constructive approach of software design, which ensures properties required a priori of the software under development. In this way the validation of the software under development is reduced to the validation of properties independent of implementation process. We reveal the inconsistence in using the concept of reachability to specify software requirements and clarify six different definitions of reachability. Two different definitions of invariance for specifying software requirements are also clarified.We then show how to synthesize the required controller or obtain software design solutions if the underlying software requirements are specified by several new combinations of reachability and invariance. The topic of this paper falls into the scope of software cybernetics that explores the interplay between software and control.
Directory of Open Access Journals (Sweden)
Omprakash Kaiwartya
2015-01-01
Full Text Available A multiobjective dynamic vehicle routing problem (M-DVRP has been identified and a time seed based solution using particle swarm optimization (TS-PSO for M-DVRP has been proposed. M-DVRP considers five objectives, namely, geographical ranking of the request, customer ranking, service time, expected reachability time, and satisfaction level of the customers. The multiobjective function of M-DVRP has four components, namely, number of vehicles, expected reachability time, and profit and satisfaction level. Three constraints of the objective function are vehicle, capacity, and reachability. In TS-PSO, first of all, the problem is partitioned into smaller size DVRPs. Secondly, the time horizon of each smaller size DVRP is divided into time seeds and the problem is solved in each time seed using particle swarm optimization. The proposed solution has been simulated in ns-2 considering real road network of New Delhi, India, and results are compared with those obtained from genetic algorithm (GA simulations. The comparison confirms that TS-PSO optimizes the multiobjective function of the identified problem better than what is offered by GA solution.
Controllability of asynchronous Boolean multiplex control networks.
Luo, Chao; Wang, Xingyuan; Liu, Hong
2014-09-01
In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.
Model Checking Vector Addition Systems with one zero-test
Bonet, Rémi; Leroux, Jérôme; Zeitoun, Marc
2012-01-01
We design a variation of the Karp-Miller algorithm to compute, in a forward manner, a finite representation of the cover (i.e., the downward closure of the reachability set) of a vector addition system with one zero-test. This algorithm yields decision procedures for several problems for these systems, open until now, such as place-boundedness or LTL model-checking. The proof techniques to handle the zero-test are based on two new notions of cover: the refined and the filtered cover. The refined cover is a hybrid between the reachability set and the classical cover. It inherits properties of the reachability set: equality of two refined covers is undecidable, even for usual Vector Addition Systems (with no zero-test), but the refined cover of a Vector Addition System is a recursive set. The second notion of cover, called the filtered cover, is the central tool of our algorithms. It inherits properties of the classical cover, and in particular, one can effectively compute a finite representation of this set, e...
So far so good: emotion in the peripersonal/extrapersonal space.
Directory of Open Access Journals (Sweden)
Berenice Valdés-Conroy
Full Text Available Current accounts of spatial cognition and human-object interaction suggest that the representation of peripersonal space depends on an action-specific system that remaps its representation according to action requirements. Here we demonstrate that this mechanism is sensitive to knowledge about properties of objects. In two experiments we explored the interaction between physical distance and object attributes (functionality, desirability, graspability, etc. through a reaching estimation task in which participants indicated if objects were near enough to be reached. Using both a real and a cutting-edge digital scenario, we demonstrate that perceived reaching distance is influenced by ease of grasp and the affective valence of an object. Objects with a positive affective valence tend to be perceived reachable at locations at which neutral or negative objects are perceived as non-reachable. In addition to this, reaction time to distant (non-reachable positive objects suggests a bias to perceive positive objects as closer than negative and neutral objects (exp. 2. These results highlight the importance of the affective valence of objects in the action-specific mapping of the peripersonal/extrapersonal space system.
Controllability of asynchronous Boolean multiplex control networks
Luo, Chao; Wang, Xingyuan; Liu, Hong
2014-09-01
In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.
A Grasp-pose Generation Method Based on Gaussian Mixture Models
Directory of Open Access Journals (Sweden)
Wenjia Wu
2015-11-01
Full Text Available A Gaussian Mixture Model (GMM-based grasp-pose generation method is proposed in this paper. Through offline training, the GMM is set up and used to depict the distribution of the robot’s reachable orientations. By dividing the robot’s workspace into small 3D voxels and training the GMM for each voxel, a look-up table covering all the workspace is built with the x, y and z positions as the index and the GMM as the entry. Through the definition of Task Space Regions (TSR, an object’s feasible grasp poses are expressed as a continuous region. With the GMM, grasp poses can be preferentially sampled from regions with high reachability probabilities in the online grasp-planning stage. The GMM can also be used as a preliminary judgement of a grasp pose’s reachability. Experiments on both a simulated and a real robot show the superiority of our method over the existing method.
Dual pathways to prospective remembering
McDaniel, Mark A.; Umanath, Sharda; Einstein, Gilles O.; Waldum, Emily R.
2015-01-01
According to the multiprocess framework (McDaniel and Einstein, 2000), the cognitive system can support prospective memory (PM) retrieval through two general pathways. One pathway depends on top–down attentional control processes that maintain activation of the intention and/or monitor the environment for the triggering or target cues that indicate that the intention should be executed. A second pathway depends on (bottom–up) spontaneous retrieval processes, processes that are often triggered by a PM target cue; critically, spontaneous retrieval is assumed not to require monitoring or active maintenance of the intention. Given demand characteristics associated with experimental settings, however, participants are often inclined to monitor, thereby potentially masking discovery of bottom–up spontaneous retrieval processes. In this article, we discuss parameters of laboratory PM paradigms to discourage monitoring and review recent behavioral evidence from such paradigms that implicate spontaneous retrieval in PM. We then re-examine the neuro-imaging evidence from the lens of the multiprocess framework and suggest some critical modifications to existing neuro-cognitive interpretations of the neuro-imaging results. These modifications illuminate possible directions and refinements for further neuro-imaging investigations of PM. PMID:26236213
Dual Pathways to Prospective Remembering
Directory of Open Access Journals (Sweden)
Mark A Mcdaniel
2015-07-01
Full Text Available According to the multiprocess framework (McDaniel & Einstein, 2000, the cognitive system can support prospective memory (PM retrieval through two general pathways. One pathway depends on top-down attentional control processes that maintain activation of the intention and/or monitor the environment for the triggering or target cues that indicate that the intention should be executed. A second pathway depends on (bottom-up spontaneous retrieval processes, processes that are often triggered by a PM target cue; critically spontaneous retrieval is assumed to not require monitoring or active maintenance of the intention. Given demand characteristics associated with experimental settings, however, participants are often inclined to monitor, thereby potentially masking discovery of bottom-up spontaneous retrieval processes. In this article, we discuss parameters of laboratory PM paradigms to discourage monitoring and review recent behavioral evidence from such paradigms that implicate spontaneous retrieval in PM. We then re-examine the neuro-imaging evidence from the lens of the multiprocess framework and suggest some critical modifications to existing neuro-cognitive interpretations of the neuro-imaging results. These modifications illuminate possible directions and refinements for further neuro-imaging investigations of PM.
An integrated dexterous robotic testbed for space applications
Li, Larry C.; Nguyen, Hai; Sauer, Edward
1992-01-01
An integrated dexterous robotic system was developed as a testbed to evaluate various robotics technologies for advanced space applications. The system configuration consisted of a Utah/MIT Dexterous Hand, a PUMA 562 arm, a stereo vision system, and a multiprocessing computer control system. In addition to these major subsystems, a proximity sensing system was integrated with the Utah/MIT Hand to provide capability for non-contact sensing of a nearby object. A high-speed fiber-optic link was used to transmit digitized proximity sensor signals back to the multiprocessing control system. The hardware system was designed to satisfy the requirements for both teleoperated and autonomous operations. The software system was designed to exploit parallel processing capability, pursue functional modularity, incorporate artificial intelligence for robot control, allow high-level symbolic robot commands, maximize reusable code, minimize compilation requirements, and provide an interactive application development and debugging environment for the end users. An overview is presented of the system hardware and software configurations, and implementation is discussed of subsystem functions.
Parallelizing TTree::Draw functionality with PROOF
Marinaci, Stefano
2014-01-01
In ROOT, the software context of this project, multi-threading is not currently an easy option, because ROOT is not by construction thread-aware and thread-safeness can only be achieved with heavy locking. Therefore, for a ROOT task, multi-processing is currently the most eective way to achieve cuncurrency. Multi-processing in ROOT is done via PROOF. PROOF is used to enable interactive analysis of large sets of ROOT les in parallel on clusters of computers or many-core machines. More generally PROOF can parallelize tasks that can be formulated as a set of independent sub-tasks. The PROOF technology is rather ecient to exploit all the CPU's provided by many-core processors. A dedicated version of PROOF, PROOF-Lite, provides an out-of-the-box solution to take full advantage of the additional cores available in today desktops or laptops. One of the items on the PROOF plan of work is to improve the inte- gration of PROOF-Lite for local processing of ROOT trees. In this project we investigate the case of the Draw ...
Energy Technology Data Exchange (ETDEWEB)
Bueno, A.D. [Universidade Estadual do Norte Fluminense, Macae, RJ (Brazil). Lab. de Engenharia e Exploracao de Petroleo (LENEP)]. E-mail: bueno@lenep.uenf.br
2003-07-01
The determination of physical properties of reservoir rocks using image analysis is a reality. The idea of a virtual laboratory where the petrophysics properties are determined with experimental samples and numerical simulations, has demonstrated an important technology in the reduction of the costs and the increase of the speed with that the information are obtained. However, most samples, after the binarization, have a large correlation length, this implies in necessity of large 3D reconstructed image. This remit the developers of models and algorithm's of image analysis of reservoir rocks to use and understand the parallel processing and clusters of workstations. This paper present a brief bibliography revision of the terms and concepts of parallel processing. The different types of parallel processing in multi processed machines are discussed. After this, the used libraries are rapidly presented, multi-processing, multi-threading, and the message passing systems (PVM and MPI). Finally, a study case, comparing the time processing between multiprocessing and multi-threading, in a cluster of 3 nodes, are presented. A set of links and references for external documents are included. (author)
Advances in spacecraft atmospheric entry guidance
Benito Manrique, Joel
In order to advance entry guidance technology two different research areas have been explored with the objective of increasing the reachable landing area and the landing accuracy for future Mars missions. Currently only the northern hemisphere of Mars is available for landing due to its low elevation. Only low elevation landing sites have the necessary atmospheric density to allow landing using current Entry, Descent and Landing (EDL) technology. In order to reach most of the Ancient Highlands, the majority of the southern hemisphere, advanced EDL technology is needed in multiple fields, including entry guidance. The first research area is the definition and applications of reachable and controllable sets for entry. The definition of the reachable and controllable sets provides a framework for the study of the capabilities of an entry vehicle in a given planet. Reachable and controllable sets can be used to comprehensively characterize the envelope of trajectories that a vehicle can fly, the sites it can reach and the entry states that can be accommodated. The sets can also be used for the evaluation of trajectory planning algorithms and to assist in the selection of the entry or landing sites. In essence, the reachable and controllable sets offer a powerful vehicle and trajectory analysis and design framework that allows for better mission design choices. In order to illustrate the use of the sets, they are computed for a representative Mars mission using two different vehicle configurations. The sets characterize the impact of the vehicle configuration on the entry capability. Furthermore, the sets are used to find the best skip-entry trajectory for a return from the Moon mission, highlighting the utility of the sets in atmospheric maneuvers other than entry. The second research area is the development of the components of an entry guidance algorithm that allow high elevation landing and provide as well high landing accuracy. The approach taken follows the
Effects of social intention on movement kinematics in cooperative actions
Directory of Open Access Journals (Sweden)
Francois eQuesque
2013-10-01
Full Text Available Optimal control models of biological movements are used to account for those internal variables that constrain voluntary goal-directed actions. They however do not take into account external environmental constraints as those associated to social intention. We investigated here the effects of the social context on kinematic characteristics of sequential actions consisting in placing an object on an initial pad (preparatory action before reaching and grasping as fast as possible the object to move it to another location (main action. Reach-to-grasp actions were performed either in an isolated condition or in the presence of a partner (audience effect, located in the near or far space (effect of shared reachable space, and who could intervene on the object in a systematic fashion (effect of social intention effect or not (effect of social uncertainty. Results showed an absence of audience effect but nevertheless an influence of the social context both on the main and the preparatory actions. In particular, a localized effect of shared reachable space was observed on the main action, which was smoother when performed within the reachable space of the partner. Furthermore, a global effect of social uncertainty was observed on both actions with faster and jerkier movements. Finally, social intention affected the preparatory action with higher wrist displacements and slower movements when the object was placed for the partner rather than placed for self-use. Overall, these results demonstrate specific effects of action space, social uncertainty and social intention on the planning of reach-to-grasp actions, in particular on the preparatory action, which was performed with no specific execution constraint. These findings underline the importance of considering the social context in optimal models of action control for human-robot interactions, in particular when focusing on the implementation of motor parameters required to afford intuitive
Novel density-based and hierarchical density-based clustering algorithms for uncertain data.
Zhang, Xianchao; Liu, Han; Zhang, Xiaotong
2017-09-01
Uncertain data has posed a great challenge to traditional clustering algorithms. Recently, several algorithms have been proposed for clustering uncertain data, and among them density-based techniques seem promising for handling data uncertainty. However, some issues like losing uncertain information, high time complexity and nonadaptive threshold have not been addressed well in the previous density-based algorithm FDBSCAN and hierarchical density-based algorithm FOPTICS. In this paper, we firstly propose a novel density-based algorithm PDBSCAN, which improves the previous FDBSCAN from the following aspects: (1) it employs a more accurate method to compute the probability that the distance between two uncertain objects is less than or equal to a boundary value, instead of the sampling-based method in FDBSCAN; (2) it introduces new definitions of probability neighborhood, support degree, core object probability, direct reachability probability, thus reducing the complexity and solving the issue of nonadaptive threshold (for core object judgement) in FDBSCAN. Then, we modify the algorithm PDBSCAN to an improved version (PDBSCANi), by using a better cluster assignment strategy to ensure that every object will be assigned to the most appropriate cluster, thus solving the issue of nonadaptive threshold (for direct density reachability judgement) in FDBSCAN. Furthermore, as PDBSCAN and PDBSCANi have difficulties for clustering uncertain data with non-uniform cluster density, we propose a novel hierarchical density-based algorithm POPTICS by extending the definitions of PDBSCAN, adding new definitions of fuzzy core distance and fuzzy reachability distance, and employing a new clustering framework. POPTICS can reveal the cluster structures of the datasets with different local densities in different regions better than PDBSCAN and PDBSCANi, and it addresses the issues in FOPTICS. Experimental results demonstrate the superiority of our proposed algorithms over the existing
Institute of Scientific and Technical Information of China (English)
崔晓风; 冯武斌; 项昌乐; 王战军; 郝会兵
2009-01-01
Based on the VR technology and maintenance engineering theory,the simulation platform of armored equipments'virtual maintenance was established in order to realize process simulation of nonimmerse virtual maintenance.Visual reachability of every maintenance unit during maintaining was evaluated quantitatively by constructing visual inner-cone of the virtual human model,and visual reachability of a certain maintenance was evaluated quantitatively by the fuzzy mathematical theory.The feasible method can be provided for analyzing and validating quantitatively qualitative index of visual reachability in the early period of scheme demonstration,research and development of new armored equipments.%基于虚拟现实技术和维修工程理论,搭建了装甲装备虚拟维修仿真平台,实现了非沉浸式虚拟维修过程仿真.通过给虚拟人模型构造视觉内切锥,对维修作业过程中每项维修作业单元的视觉可达性给出了定量评价,结合模糊数学理论,对某一维修作业的视觉可达性给出了定量评估方法.本文为军方在新型装甲装备的方案论证和研制初期提供了维修性中的可达性等定性指标的定量化分析和验证的可行方法.
Autonomous Mission Design in Extreme Orbit Environments
Surovik, David Allen
An algorithm for autonomous online mission design at asteroids, comets, and small moons is developed to meet the novel challenges of their complex non-Keplerian orbit environments, which render traditional methods inapplicable. The core concept of abstract reachability analysis, in which a set of impulsive maneuvering options is mapped onto a space of high-level mission outcomes, is applied to enable goal-oriented decision-making with robustness to uncertainty. These nuanced analyses are efficiently computed by utilizing a heuristic-based adaptive sampling scheme that either maximizes an objective function for autonomous planning or resolves details of interest for preliminary analysis and general study. Illustrative examples reveal the chaotic nature of small body systems through the structure of various families of reachable orbits, such as those that facilitate close-range observation of targeted surface locations or achieve soft impact upon them. In order to fulfill extensive sets of observation tasks, the single-maneuver design method is implemented in a receding-horizon framework such that a complete mission is constructed on-the-fly one piece at a time. Long-term performance and convergence are assured by augmenting the objective function with a prospect heuristic, which approximates the likelihood that a reachable end-state will benefit the subsequent planning horizon. When state and model uncertainty produce larger trajectory deviations than were anticipated, the next control horizon is advanced to allow for corrective action -- a low-frequency form of feedback control. Through Monte Carlo analysis, the planning algorithm is ultimately demonstrated to produce mission profiles that vary drastically in their physical paths but nonetheless consistently complete all goals, suggesting a high degree of flexibility. It is further shown that the objective function can be tuned to preferentially minimize fuel cost or mission duration, as well as to optimize
Secularization, Union Formation Practices, and Marital Stability: Evidence from Italy.
Impicciatore, Roberto; Billari, Francesco C
2012-05-01
Descriptive statistics indicate that civil marriages and marriages preceded by premarital cohabitation are more unstable, i.e., more frequently followed by divorce. However, the literature has shown that selectivity plays an important role in the relationship between premarital cohabitation and union dissolution. We do not have evidence to date regarding the selectivity in the effect of civil marriage. The Italian case appears particularly interesting given the recent diffusion of premarital cohabitation and civil marriage. Using micro-level data from a national-level representative survey conducted in 2003, we develop a multiprocess model that allows unobserved heterogeneity to be correlated across the three decisions (premarital cohabitation, civil marriage, and divorce). Our results show that selectivity is the main factor that explains the higher divorce rates among those who experience premarital cohabitation and a civil marriage. Net of selectivity, the causal effect on union dissolution disappears.
Powerful scriptable ray tracing package xrt
Klementiev, Konstantin; Chernikov, Roman
2014-09-01
We present an open source python based ray tracing tool that offers several useful features in graphical presentation, material properties, advanced calculations of synchrotron sources, implementation of diffractive and refractive elements, complex (also closed) surfaces and multiprocessing. The package has many usage examples which are supplied together with the code and visualized on its web page. We exemplify the present version by modeling (i) a curved crystal analyzer, (ii) a quarter wave plate, (iii) Bragg-Fresnel optics and (iv) multiple reflective and non-sequential optics (polycapillary). The present version implements the use of OpenCL framework that executes calculations on both CPUs and GPUs. Currently, the calculations of an undulator source on a GPU show a gain of about two orders of magnitude in computing time. The development version is successful in modelling the wavefront propagation. Two examples of diffraction on a plane mirror and a plane blazed grating are given for a beam with a finite energy band.
ATLAS Metadata Infrastructure Evolution for Run 2 and Beyond
van Gemmeren, Peter; The ATLAS collaboration; Malon, David; Vaniachine, Alexandre
2015-01-01
ATLAS developed and employed for Run 1 of the Large Hadron Collider a sophisticated infrastructure for metadata handling in event processing jobs. This infrastructure profits from a rich feature set provided by the ATLAS execution control framework, including standardized interfaces and invocation mechanisms for tools and services, segregation of transient data stores with concomitant object lifetime management, and mechanisms for handling occurrences asynchronous to the control framework’s state machine transitions. This metadata infrastructure is evolving and being extended for Run 2 to allow its use and reuse in downstream physics analyses, analyses that may or may not utilize the ATLAS control framework. At the same time, multiprocessing versions of the control framework and the requirements of future multithreaded frameworks are leading to redesign of components that use an incident-handling approach to asynchrony. The increased use of scatter-gather architectures, both local and distributed, requires ...
Evaluating Google Compute Engine with PROOF
Ganis, Gerardo; Panitkin, Sergey
2014-06-01
The advent of private and commercial cloud platforms has opened the question of evaluating the cost-effectiveness of such solution for computing in High Energy Physics . Google Compute Engine (GCE) is a IaaS product launched by Google as an experimental platform during 2012 and now open to the public market. In this contribution we present the results of a set of CPU-intensive and I/O-intensive tests we have run with PROOF on a GCE resources made available by Google for test purposes. We have run tests on large scale PROOF clusters (up to 1000 workers) to study the overall scalability of coordinated multi-process jobs. We have studied and compared the performance of ephemeral and persistent storage with PROOF-Lite on the single machines and of standard PROOF on the whole cluster. We will discuss our results in perspective, in particular with respect to the typical analysis needs of an LHC experiment.
A parallel finite-difference method for computational aerodynamics
Swisshelm, Julie M.
1989-01-01
A finite-difference scheme for solving complex three-dimensional aerodynamic flow on parallel-processing supercomputers is presented. The method consists of a basic flow solver with multigrid convergence acceleration, embedded grid refinements, and a zonal equation scheme. Multitasking and vectorization have been incorporated into the algorithm. Results obtained include multiprocessed flow simulations from the Cray X-MP and Cray-2. Speedups as high as 3.3 for the two-dimensional case and 3.5 for segments of the three-dimensional case have been achieved on the Cray-2. The entire solver attained a factor of 2.7 improvement over its unitasked version on the Cray-2. The performance of the parallel algorithm on each machine is analyzed.
Institute of Scientific and Technical Information of China (English)
飞思卡尔半导体公司
2011-01-01
2011年9月6日,德克萨斯州奥斯汀市讯—飞思卡尔半导体公司(NYSE:FSL)选择Mentor Graphics Corporation( NASDAQ:MENT)开发包含高级算法和信号处理功能的软件库,该软件库专门针对最新版飞思卡尔AltiVec处理引擎进行优化.面向飞思卡尔AltiVec技术的Mentor(R) Embedded Performance Library旨在帮助飞思卡尔近期推出的QorIQ Advanced Multiprocessing(AMP)处理器利用最新的AltiVec引擎实现性能的最大化,同时使软件开发人员提高生产效率.
Embedded and real-time operating systems
Wang, K C
2017-01-01
This book covers the basic concepts and principles of operating systems, showing how to apply them to the design and implementation of complete operating systems for embedded and real-time systems. It includes all the foundational and background information on ARM architecture, ARM instructions and programming, toolchain for developing programs, virtual machines for software implementation and testing, program execution image, function call conventions, run-time stack usage and link C programs with assembly code. It describes the design and implementation of a complete OS for embedded systems in incremental steps, explaining the design principles and implementation techniques. For Symmetric Multiprocessing (SMP) embedded systems, the author examines the ARM MPcore processors, which include the SCU and GIC for interrupts routing and interprocessor communication and synchronization by Software Generated Interrupts (SGIs). Throughout the book, complete working sample systems demonstrate the design principles and...
A Cluster- Based Secure Active Network Environment
Institute of Scientific and Technical Information of China (English)
CHEN Xiao-lin; ZHOU Jing-yang; DAI Han; LU Sang-lu; CHEN Gui-hai
2005-01-01
We introduce a cluster-based secure active network environment (CSANE) which separates the processing of IP packets from that of active packets in active routers. In this environment, the active code authorized or trusted by privileged users is executed in the secure execution environment (EE) of the active router, while others are executed in the secure EE of the nodes in the distributed shared memory (DSM) cluster. With the supports of a multi-process Java virtual machine and KeyNote, untrusted active packets are controlled to securely consume resource. The DSM consistency management makes that active packets can be parallelly processed in the DSM cluster as if they were processed one by one in ANTS (Active Network Transport System). We demonstrate that CSANE has good security and scalability, but imposing little changes on traditional routers.
Akram, Muhammad Adeel; Sarfaraz, Muhammad Masood
2012-01-01
The demand for high performance embedded processors, for consumer electronics, is rapidly increasing for the past few years. Many of these embedded processors depend upon custom built Instruction Ser Architecture (ISA) such as game processor (GPU), multimedia processors, DSP processors etc. Primary requirement for consumer electronic industry is low cost with high performance and low power consumption. A lot of research has been evolved to enhance the performance of embedded processors through parallel computing. But some of them focus superscalar processors i.e. single processors with more resources like Instruction Level Parallelism (ILP) which includes Very Long Instruction Word (VLIW) architecture, custom instruction set extensible processor architecture and others require more number of processing units on a single chip like Thread Level Parallelism (TLP) that includes Simultaneous Multithreading (SMT), Chip Multithreading (CMT) and Chip Multiprocessing (CMP). In this paper, we present a new technique, n...
[Series: Medical Applications of the PHITS Code (2): Acceleration by Parallel Computing].
Furuta, Takuya; Sato, Tatsuhiko
2015-01-01
Time-consuming Monte Carlo dose calculation becomes feasible owing to the development of computer technology. However, the recent development is due to emergence of the multi-core high performance computers. Therefore, parallel computing becomes a key to achieve good performance of software programs. A Monte Carlo simulation code PHITS contains two parallel computing functions, the distributed-memory parallelization using protocols of message passing interface (MPI) and the shared-memory parallelization using open multi-processing (OpenMP) directives. Users can choose the two functions according to their needs. This paper gives the explanation of the two functions with their advantages and disadvantages. Some test applications are also provided to show their performance using a typical multi-core high performance workstation.
Computational mathematics models, methods, and analysis with Matlab and MPI
White, Robert E
2004-01-01
Computational Mathematics: Models, Methods, and Analysis with MATLAB and MPI explores and illustrates this process. Each section of the first six chapters is motivated by a specific application. The author applies a model, selects a numerical method, implements computer simulations, and assesses the ensuing results. These chapters include an abundance of MATLAB code. By studying the code instead of using it as a "black box, " you take the first step toward more sophisticated numerical modeling. The last four chapters focus on multiprocessing algorithms implemented using message passing interface (MPI). These chapters include Fortran 9x codes that illustrate the basic MPI subroutines and revisit the applications of the previous chapters from a parallel implementation perspective. All of the codes are available for download from www4.ncsu.edu./~white.This book is not just about math, not just about computing, and not just about applications, but about all three--in other words, computational science. Whether us...
The Boom in 3D-Printed Sensor Technology
Xu, Yuanyuan; Wu, Xiaoyue; Guo, Xiao; Kong, Bin; Zhang, Min; Qian, Xiang; Mi, Shengli; Sun, Wei
2017-01-01
Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. Recent advances in 3D printing and electronics have brought us closer to sensors with multiplex advantages, and additive manufacturing approaches offer a new scope for sensor fabrication. To this end, we review the recent advances in 3D-printed cutting-edge sensors. These achievements demonstrate the successful application of 3D-printing technology in sensor fabrication, and the selected studies deeply explore the potential for creating sensors with higher performance. Further development of multi-process 3D printing is expected to expand future sensor utility and availability. PMID:28534832
ATLAS Metadata Infrastructure Evolution for Run 2 and Beyond
van Gemmeren, Peter; The ATLAS collaboration; Cranshaw, Jack; Vaniachine, Alexandre
2015-01-01
ATLAS developed and employed for Run 1 of the Large Hadron Collider a sophisticated infrastructure for metadata handling in event processing jobs. This infrastructure profits from a rich feature set provided by the ATLAS execution control framework, including standardized interfaces and invocation mechanisms for tools and services, segregation of transient data stores with concomitant object lifetime management, and mechanisms for handling occurrences asynchronous to the control framework’s state machine transitions. This metadata infrastructure is evolving and being extended for Run 2 to allow its use and reuse in downstream physics analyses, analyses that may or may not utilize the ATLAS control framework. At the same time, multiprocessing versions of the control framework and the requirements of future multithreaded frameworks are leading to redesign of components that use an incident-handling approach to asynchrony. The increased use of scatter-gather architectures, both local and distributed, requires ...
p4-Linda: A portable implementation of Linda
Energy Technology Data Exchange (ETDEWEB)
Butler, R.M.; Leveton, A.L. [University of North Florida, Jacksonville, FL (United States). Div. of Computer and Information Science; Lusk, E.L. [Argonne National Lab., IL (United States)
1993-07-01
Facilities such as interprocess communication and protection of shared resources have been added to operating systems to support multiprogramming and have since been adapted to exploit explicit multiprocessing within the scope of two models: the shared-memory model and the distributed (message-passing) model. When multiprocessors (or networks of heterogeneous processors) are used for explicit parallelism, the difference between these models is exposed to the programmer. The p4 tool set was originally developed to buffer the programmer from synchronization issues while offering an added advantage in portability, however two models are often still needed to develop parallel algorithms. We provide two implementations of Linda in an attempt to support a single high-level programming model on top of the existing paradigms in order to provide a consistent semantics regardless of the underlying model. Linda`s fundamental properties associated with generative communication eliminate the distinction between shared and distributed memory.
Vacuum mechatronics first international workshop
Energy Technology Data Exchange (ETDEWEB)
Belinski, S.E.; Shirazi, M.; Hackwood, S.; Beni, G. (eds.) (California Univ., Santa Barbara, CA (USA))
1989-01-01
This report contains papers on the following topics: proposed epitaxial thin film growth in the ultra-vacuum of space; particle monitoring and control in vacuum processing equipment; electrostatic dust collector for use in vacuum systems; materials evaluation of an electrically noisy vacuum slip ring assembly; an overview of lubrication and associated materials for vacuum service; the usage of lubricants in a vacuum environment; guidelines and practical applications for lubrication in vacuum; recent development in leak detector and calibrator designs; the durability of ballscrews for ultrahigh vacuum; vacuum-compatible robot for self-contained manufacturing systems; the design, fabrication, and assembly of an advanced vacuum robotics system for space payload calibration; design criteria for mechanisms used in space; and concepts and requirements for semiconductor multiprocess integration in vacuum. These papers are indexed separately elsewhere.
Young-S., Luis E; Muruganandam, Paulsamy; Adhikari, Sadhan K; Balaz, Antun
2016-01-01
We present new version of previously published Fortran and C programs for solving the Gross-Pitaevskii equation for a Bose-Einstein condensate with contact interaction in one, two and three spatial dimensions in imaginary and real time, yielding both stationary and non-stationary solutions. To reduce the execution time on multicore processors, new versions of parallelized programs are developed using Open Multi-Processing (OpenMP) interface. The input in the previous versions of programs was the mathematical quantity nonlinearity for dimensionless form of Gross-Pitaevskii equation, whereas in the present programs the inputs are quantities of experimental interest, such as, number of atoms, scattering length, oscillator length for the trap, etc. New output files for some integrated one- and two-dimensional densities of experimental interest are given. We also present speedup test results for the new programs.
Classifying sows' activity types from acceleration patterns
DEFF Research Database (Denmark)
Cornou, Cecile; Lundbye-Christensen, Søren
2008-01-01
-dimensional axes, plus the length of the acceleration vector) are selected for each activity. Each time series is modeled using a Dynamic Linear Model with cyclic components. The classification method, based on a Multi-Process Kalman Filter (MPKF), is applied to a total of 15 times series of 120 observations......An automated method of classifying sow activity using acceleration measurements would allow the individual sow's behavior to be monitored throughout the reproductive cycle; applications for detecting behaviors characteristic of estrus and farrowing or to monitor illness and welfare can be foreseen....... This article suggests a method of classifying five types of activity exhibited by group-housed sows. The method involves the measurement of acceleration in three dimensions. The five activities are: feeding, walking, rooting, lying laterally and lying sternally. Four time series of acceleration (the three...
Biborski, Andrzej; Kądzielawa, Andrzej P.; Spałek, Józef
2015-12-01
An efficient computational scheme devised for investigations of ground state properties of the electronically correlated systems is presented. As an example, (H2)n chain is considered with the long-range electron-electron interactions taken into account. The implemented procedure covers: (i) single-particle Wannier wave-function basis construction in the correlated state, (ii) microscopic parameters calculation, and (iii) ground state energy optimization. The optimization loop is based on highly effective process-pool solution - specific root-workers approach. The hierarchical, two-level parallelism was applied: both shared (by use of Open Multi-Processing) and distributed (by use of Message Passing Interface) memory models were utilized. We discuss in detail the feature that such approach results in a substantial increase of the calculation speed reaching factor of 300 for the fully parallelized solution. The scheme elaborated in detail reflects the situation in which the most demanding task is the single-particle basis optimization.
Computational structural mechanics for engine structures
Chamis, C. C.
1989-01-01
The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.
Improving Packet Processing Efficiency on Multi-core Architectures with Single Input Queue
Directory of Open Access Journals (Sweden)
Peter Orosz
2012-06-01
Full Text Available Generic purpose multi-core PC architectures are facing performance challenges of high rate packet reception on gigabit per second and higher speed network interfaces. In order to assign a CPU core to a networking softIRQ, the single input queue design of the low-level packet processing subsystem relies on the kernel's Symmetric Multiprocessing (SMP scheduler, which does not perform load balancing of the softIRQ instances between the CPU cores. In practice, when single receive queue is used all of the softIRQs are assigned to a single CPU core. This typical arrangement could easily drive to CPU resource exhaustion and high packet loss ratio on high bandwidth interfaces. The non-steady state of the system is triggered by the high arrival rate of the packets. This work presents a proposal for improving the packet processing efficiency in single input queue multi-core systems.
schwimmbad: A uniform interface to parallel processing pools in Python
Price-Whelan, Adrian M.; Foreman-Mackey, Daniel
2017-09-01
Many scientific and computing problems require doing some calculation on all elements of some data set. If the calculations can be executed in parallel (i.e. without any communication between calculations), these problems are said to be perfectly parallel. On computers with multiple processing cores, these tasks can be distributed and executed in parallel to greatly improve performance. A common paradigm for handling these distributed computing problems is to use a processing "pool": the "tasks" (the data) are passed in bulk to the pool, and the pool handles distributing the tasks to a number of worker processes when available. schwimmbad provides a uniform interface to parallel processing pools and enables switching easily between local development (e.g., serial processing or with multiprocessing) and deployment on a cluster or supercomputer (via, e.g., MPI or JobLib).
Comparative Implementation of High Performance Computing for Power System Dynamic Simulations
Energy Technology Data Exchange (ETDEWEB)
Jin, Shuangshuang; Huang, Zhenyu; Diao, Ruisheng; Wu, Di; Chen, Yousu
2017-05-01
Dynamic simulation for transient stability assessment is one of the most important, but intensive, computations for power system planning and operation. Present commercial software is mainly designed for sequential computation to run a single simulation, which is very time consuming with a single processer. The application of High Performance Computing (HPC) to dynamic simulations is very promising in accelerating the computing process by parallelizing its kernel algorithms while maintaining the same level of computation accuracy. This paper describes the comparative implementation of four parallel dynamic simulation schemes in two state-of-the-art HPC environments: Message Passing Interface (MPI) and Open Multi-Processing (OpenMP). These implementations serve to match the application with dedicated multi-processor computing hardware and maximize the utilization and benefits of HPC during the development process.
The investigation of an autonomous intelligent mobile robot system for indoor environment navigation
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The autonomous mobile robotics system designed and implemented for indoor environment navigation is a nonholonomic differential drive system with two driving wheels mounted on the same axis driven by two PID controlled motors and two caster wheels mounted in the front and back respectively. It is furnished with multiple kinds of sensors such as IR detectors, ultrasonic sensors, laser line generators and cameras, constituting a per ceiving system for exploring its surroundings. Its computation source is a simultaneously running system com posed of multiprocessor with multitask and multiprocessing programming. Hybrid control architecture is em ployed on the mobile robot to perform complex tasks. The mobile robot system is implemented at the Center for Intelligent Design, Automation and Manufacturing of City University of Hong Kong.
New approach to data preparation and processing for high-density patterns
Thuren, Anders; Sandstrom, Torbjoern
1997-07-01
A modern pattern generator needs very high data-handling capacity, partly because the number of features per mask is growing, partly because OPC and other sophisticated lithographic enhancements increase the complexity. MICRONIC makes a wide range of laser pattern generators for display, reticles and other electronics applications, and therefore needs a hardware/software datapath that is configurable over a wide range of requirements and cost levels. An extendible multiprocessor architecture offers this flexibility: possibility for multiprocessing for very high power, and at the same time ability to configure small systems for low-end applications. Preliminary benchmarks show a speed increase over previous systems by 10 to 60 times for a single processor.
Implementation of Parallel Dynamic Simulation on Shared-Memory vs. Distributed-Memory Environments
Energy Technology Data Exchange (ETDEWEB)
Jin, Shuangshuang; Chen, Yousu; Wu, Di; Diao, Ruisheng; Huang, Zhenyu
2015-12-09
Power system dynamic simulation computes the system response to a sequence of large disturbance, such as sudden changes in generation or load, or a network short circuit followed by protective branch switching operation. It consists of a large set of differential and algebraic equations, which is computational intensive and challenging to solve using single-processor based dynamic simulation solution. High-performance computing (HPC) based parallel computing is a very promising technology to speed up the computation and facilitate the simulation process. This paper presents two different parallel implementations of power grid dynamic simulation using Open Multi-processing (OpenMP) on shared-memory platform, and Message Passing Interface (MPI) on distributed-memory clusters, respectively. The difference of the parallel simulation algorithms and architectures of the two HPC technologies are illustrated, and their performances for running parallel dynamic simulation are compared and demonstrated.
A Review on Evaluation Metho ds of Climate Mo deling
Institute of Scientific and Technical Information of China (English)
ZHAO Zong-Ci; LUO Yong; HUANG Jian-Bin
2013-01-01
There is scientific progress in the evaluation methods of recent Earth system models (ESMs). Methods range from single variable to multi-variables, multi-processes, multi-phenomena quantitative evaluations in five layers (spheres) of the Earth system, from climatic mean assessment to climate change (such as trends, periodicity, interdecadal variability), extreme values, abnormal characters and quantitative evaluations of phenomena, from qualitative assessment to quanti-tative calculation of reliability and uncertainty for model simulations. Researchers started considering independence and similarity between models in multi-model use, as well as the quantitative evaluation of climate prediction and projection effect and the quantitative uncertainty contribution analysis. In this manuscript, the simulations and pro jections by both CMIP5 and CMIP3 that have been published after 2007 are reviewed and summarized.
CSP for Executable Scientific Workflows
DEFF Research Database (Denmark)
Friborg, Rune Møllegaard
and can usually benefit performance-wise from both multiprocessing, cluster and grid environments. PyCSP is an implementation of Communicating Sequential Processes (CSP) for the Python programming language and takes advantage of CSP's formal and verifiable approach to controlling concurrency...... and the readability of Python source code. Python is a popular programming language in the scientific community, with many scientific libraries (modules) and simple integration to external languages. This thesis presents a PyCSP extended with many new features and a more robust implementation to allow scientific...... is demonstrated through examples. By providing a robust library for organising scientific workflows in a Python application I hope to inspire scientific users to adopt PyCSP. As a proof-of-concept this thesis demonstrates three scientific applications: kNN, stochastic minimum search and McStas to scale well...
Liu, Bin; Wu, Hao; Zhang, Deyuan; Wang, Xiaolong; Chou, Kuo-Chen
2017-01-05
To expedite the pace in conducting genome/proteome analysis, we have developed a Python package called Pse-Analysis. The powerful package can automatically complete the following five procedures: (1) sample feature extraction, (2) optimal parameter selection, (3) model training, (4) cross validation, and (5) evaluating prediction quality. All the work a user needs to do is to input a benchmark dataset along with the query biological sequences concerned. Based on the benchmark dataset, Pse-Analysis will automatically construct an ideal predictor, followed by yielding the predicted results for the submitted query samples. All the aforementioned tedious jobs can be automatically done by the computer. Moreover, the multiprocessing technique was adopted to enhance computational speed by about 6 folds. The Pse-Analysis Python package is freely accessible to the public at http://bioinformatics.hitsz.edu.cn/Pse-Analysis/, and can be directly run on Windows, Linux, and Unix.
Measures of Bayesian Reasoning Performance on 'Normal' and 'Natural' Frequency Tasks.
Stock, Rosemary; Fisk, John E; Montgomery, Catharine
2016-01-01
While the majority of similar studies examining Bayesian reasoning investigate how participants avoid common errors such as base-rate neglect, the current research also examines whether different formats (frequency and probability) lead to a difference in levels of absolute accuracy. In Study One, older (≥60 years) and younger (18 to 29 years) participants completed tasks in probability and normalized frequency formats. In Study 2, participants completed tasks in probability and natural frequency formats. Findings are that frequencies lead to less over-estimation, particularly in natural frequency tasks, which also reveal an interaction between age and task format whereby older adults seem unaffected by format. There was no association found between format and the avoidance of errors such as base-rate neglect. Findings are discussed in the light of dual and multi-process theories of reasoning, having failed to support the theory that frequency formats elicit System 2 reasoning processes.
CERN. Geneva
2015-01-01
FAIR is a new, unique international accelerator facility for the research with antiprotons and ions. It is being built at the GSI Darmstadt in Hesse, Germany. The commonalities between the ALICE and FAIR experiments and their computing requirements led to the development of a common software framework in an experiment independent way; ALFA (ALICE-FAIR framework). ALFA is designed for high quality parallel data processing and reconstruction on heterogeneous computing systems. It provides a data transport layer and the capability to coordinate multiple data processing components. ALFA is a flexible, elastic system which balances reliability and ease of development with performance by using a message based multi-processing in addition to multi-threading. The framework allows for usage of heterogeneous computing architectures by offloading (portions of code are accelerated on the device) or natively (where the full program is executed on the device ).
Pérez-Rodríguez, P; Gianola, D; Weigel, K A; Rosa, G J M; Crossa, J
2013-08-01
In recent years, several statistical models have been developed for predicting genetic values for complex traits using information on dense molecular markers, pedigrees, or both. These models include, among others, the Bayesian regularized neural networks (BRNN) that have been widely used in prediction problems in other fields of application and, more recently, for genome-enabled prediction. The R package described here (brnn) implements BRNN models and extends these to include both additive and dominance effects. The implementation takes advantage of multicore architectures via a parallel computing approach using openMP (Open Multiprocessing) for the computations. This note briefly describes the classes of models that can be fitted using the brnn package, and it also illustrates its use through several real examples.
LHCb: Preparing the Gaudi-Framework and the DIRAC-WMS for Multicore Job Submission
Rauschmayr, N
2013-01-01
Due to the continuously increasing number of cores on modern CPUs, it is important to adapt HEP applications. This must be done at different levels: the software which must support parallelization and the scheduling has to differ between multicore and singlecore jobs. The LHCb software framework (GAUDI) provides a parallel prototype (GaudiMP), based on the multiprocessing approach. It allows a reduction of the overall memory footprint and a coordinated access to data via separated reader and writer processes. A comparison between the parallel prototype and multiple independent Gaudi jobs in respect to CPU-time and memory consumption will be shown. In the context of parallelization speedup is the most important metric, as it shows how software scales with the number of cores. It is influenced by many factors, due to software limitations like synchronization, but also due to hardware configurations, like frequency scaling. Those limitations and their dependencies will be discussed and the influence of hardware ...
CSP for Executable Scientific Workflows
DEFF Research Database (Denmark)
Friborg, Rune Møllegaard
is demonstrated through examples. By providing a robust library for organising scientific workflows in a Python application I hope to inspire scientific users to adopt PyCSP. As a proof-of-concept this thesis demonstrates three scientific applications: kNN, stochastic minimum search and McStas to scale well......This thesis presents CSP as a means of orchestrating the execution of tasks in a scientific workflow. Scientific workflow systems are popular in a wide range of scientific areas, where tasks are organised in directed graphs. Execution of such graphs is handled by the scientific workflow systems...... on multi-processing and cluster computing using PyCSP. Additionally, McStas is demonstrated to utilise grid computing resources using PyCSP. Finally, this thesis presents a new dynamic channel model, which has not yet been implemented for PyCSP. The dynamic channel is able to change the internal...
Multi-core job submission and grid resource scheduling for ATLAS AthenaMP
Crooks, D; The ATLAS collaboration; Harrington, R; Jha, M; Maeno, T; Purdie, S; Severini, H; Skipsey, S; Tsulaia, V; Walker, R; Washbrook, A
2012-01-01
AthenaMP is the multi-core implementation of the ATLAS software framework and allows the efficient sharing of memory pages between multiple threads of execution. This has now been validated for production and delivers a significant reduction on overall memory footprint with negligible CPU overhead. Before AthenaMP can be routinely run on the LHC Computing Grid, it must be determined how the computing resources available to ATLAS can best exploit the notable improvements delivered by switching to this multi-process model. A study into the effectiveness and scalability of AthenaMP in a production environment will be presented. Best practices for configuring the main LRMS implementations currently used by Tier-2 sites will be identified in the context of multi-core job optimisation.
Multi-core job submission and grid resource scheduling for ATLAS AthenaMP
Crooks, D.; Calafiura, P.; Harrington, R.; Jha, M.; Maeno, T.; Purdie, S.; Severini, H.; Skipsey, S.; Tsulaia, V.; Walker, R.; Washbrook, A.
2012-12-01
AthenaMP is the multi-core implementation of the ATLAS software framework and allows the efficient sharing of memory pages between multiple threads of execution. This has now been validated for production and delivers a significant reduction on the overall application memory footprint with negligible CPU overhead. Before AthenaMP can be routinely run on the LHC Computing Grid it must be determined how the computing resources available to ATLAS can best exploit the notable improvements delivered by switching to this multi-process model. A study into the effectiveness and scalability of AthenaMP in a production environment will be presented. Best practices for configuring the main LRMS implementations currently used by grid sites will be identified in the context of multi-core scheduling optimisation.
Art and brain: insights from neuropsychology, biology and evolution.
Zaidel, Dahlia W
2010-02-01
Art is a uniquely human activity associated fundamentally with symbolic and abstract cognition. Its practice in human societies throughout the world, coupled with seeming non-functionality, has led to three major brain theories of art. (1) The localized brain regions and pathways theory links art to multiple neural regions. (2) The display of art and its aesthetics theory is tied to the biological motivation of courtship signals and mate selection strategies in animals. (3) The evolutionary theory links the symbolic nature of art to critical pivotal brain changes in Homo sapiens supporting increased development of language and hierarchical social grouping. Collectively, these theories point to art as a multi-process cognition dependent on diverse brain regions and on redundancy in art-related functional representation.
Subcubic Control Flow Analysis Algorithms
DEFF Research Database (Denmark)
Midtgaard, Jan; Van Horn, David
We give the first direct subcubic algorithm for performing control flow analysis of higher-order functional programs. Despite the long held belief that inclusion-based flow analysis could not surpass the ``cubic bottleneck, '' we apply known set compression techniques to obtain an algorithm...... that runs in time O(n^3/log n) on a unit cost random-access memory model machine. Moreover, we refine the initial flow analysis into two more precise analyses incorporating notions of reachability. We give subcubic algorithms for these more precise analyses and relate them to an existing analysis from...
Path Based Mapping Technique for Robots
Directory of Open Access Journals (Sweden)
Amiraj Dhawan
2013-05-01
Full Text Available The purpose of this paper is to explore a new way of autonomous mapping. Current systems using perception techniques like LAZER or SONAR use probabilistic methods and have a drawback of allowing considerable uncertainty in the mapping process. Our approach is to break down the environment, specifically indoor, into reachable areas and objects, separated by boundaries, and identifying their shape, to render various navigable paths around them. This is a novel method to do away with uncertainties, as far as possible, at the cost of temporal efficiency. Also this system demands only minimum and cheap hardware, as it relies on only Infra-Red sensors to do the job.
Minimal Time Problem with Impulsive Controls
Energy Technology Data Exchange (ETDEWEB)
Kunisch, Karl, E-mail: karl.kunisch@uni-graz.at [University of Graz, Institute for Mathematics and Scientific Computing (Austria); Rao, Zhiping, E-mail: zhiping.rao@ricam.oeaw.ac.at [Austrian Academy of Sciences, Radon Institute of Computational and Applied Mathematics (Austria)
2017-02-15
Time optimal control problems for systems with impulsive controls are investigated. Sufficient conditions for the existence of time optimal controls are given. A dynamical programming principle is derived and Lipschitz continuity of an appropriately defined value functional is established. The value functional satisfies a Hamilton–Jacobi–Bellman equation in the viscosity sense. A numerical example for a rider-swing system is presented and it is shown that the reachable set is enlargered by allowing for impulsive controls, when compared to nonimpulsive controls.
Efficient On-the-fly Algorithms for the Analysis of Timed Games
DEFF Research Database (Denmark)
Cassez, Franck; David, Alexandre; Fleury, Emmanuel;
2005-01-01
-checking of finite-state systems. Being on-the-fly, the symbolic algorithm may terminate long before having explored the entire state-space. Also the individual steps of the algorithm are carried out efficiently by the use of so-called zones as the underlying data structure. Various optimizations of the basic...... symbolic algorithm are proposed as well as methods for obtaining time-optimal winning strategies (for reachability games). Extensive evaluation of an experimental implementation of the algorithm yields very encouraging performance results....
H∞ Observer-Based Sliding Mode Control for Uncertain Stochastic Systems with Time-Varying Delays
Directory of Open Access Journals (Sweden)
Peng Zhang
2013-01-01
Full Text Available The paper is concerned with sliding mode control for uncertain time-delay systems subjected to input nonlinearity and stochastic perturbations. Using the sliding mode control, a robust law is derived to guarantee the reachability of the sliding surface in a finite time interval. The sufficient conditions on asymptotic stability of the error system and sliding mode dynamics with disturbance attenuation level are presented in terms of linear matrix inequalities (LMIs. Finally, an example is provided to illustrate the efficiency and effectiveness of the proposed method.
Integral sliding mode control for a class of nonlinear neutral systems with time-varying delays
Institute of Scientific and Technical Information of China (English)
Lou Xu-Yang; Cui Bao-Tong
2008-01-01
This paper focuses on sliding mode control problems for a class of nonlinear neutral systems with time-varying delays. An integral sliding surface is firstly constructed. Then it finds a useful criteria to guarantee the global stability for the nonlinear neutral systems with time-varying delays in the specified switching surface, whose condition is formulated as linear matrix inequality. The synthesized sliding mode controller guarantees the reachability of the specified sliding surface. Finally, a numerical simulation validates the effectiveness and feasibility of the proposed technique.
La rentabilité de la fidélisation du consommateur : 3 essais complémentaires.
Vallaud, Thierry
2013-01-01
In this thesis based on works the author goes from two previous studies on the profitability of loyalty and customer potential determination to make a statement : part of the profitability of loyalty and of the potential for a brand is based on the reachable share of turnover done by the competition ; the catch rate.In this new work it is shown that the catch rate is based on the elasticity of the share of category requirement. From a review of the literature and several modeling on scanning ...
Surveys in differential-algebraic equations III
Reis, Timo
2015-01-01
The present volume comprises survey articles on various fields of Differential-Algebraic Equations (DAEs), which have widespread applications in controlled dynamical systems, especially in mechanical and electrical engineering and a strong relation to (ordinary) differential equations. The individual chapters provide reviews, presentations of the current state of research and new concepts in - Flexibility of DAE formulations - Reachability analysis and deterministic global optimization - Numerical linear algebra methods - Boundary value problems The results are presented in an accessible style, making this book suitable not only for active researchers but also for graduate students (with a good knowledge of the basic principles of DAEs) for self-study.
Annual Progress Report for July 1, 1978 through June 30, 1979,
1979-08-01
Neubauer, H. L. Wong, T. W. Finin, ’T. W. Norton, R. L. Wrigley , J. D., Jr. Firman, M. A. Oakes, M. W. Yang, P. Fletcher, R. J. Oberstar, J. Yau, J...Intersymbol Interference in Baseband Channels, Val Anthony DiEuliis (November 1978). R-831 Proximity and Reachability in the Plane, Der-Tsai Lee (ACT-12...S. Brass T. C. Lo J. D. Wrigley , Jr. B. Chin L. C. Rathbun 7.1 Surface Chemistry* Continuing emphasis in this area has been upon two related topics
DEFF Research Database (Denmark)
Breumlund, Anne; Hansen, Inger Bruun
2011-01-01
by a recent tool called TAPAAL which, among others, further extends TAPN with invariants on places in order to model urgency. The decidability of boundedness and coverability for this extended model has not yet been considered. We present a reduc- tion from two-counter Minsky machines to TAPN with invariants......Timed-Arc Petri Nets (TAPN) is a well studied extension of the classical Petri net model where tokens are decorated with real numbers that represent their age. Unlike reachability, which is known to be undecidable for TAPN, boundedness and coverability remain decid- able. The model is supported...
A unified Lie systems theory for closed and open Markovian dynamical quantum systems
Energy Technology Data Exchange (ETDEWEB)
Schulte-Herbrueggen, Thomas [Technical University of Munich (TUM) (Germany); Dirr, Gunther [University of Wuerzburg (Germany)
2016-07-01
Lie groups and Lie semigroups with their symmetries provide a unified framework to pinpoint the dynamic behaviour of closed and open quantum systems under all kinds of controls. Recently, we showed that all Markovian quantum maps can be represented by Lie semigroups. These semigroups come with the geometry of affine maps, whose translational parts determine the respective fixed points. We exploit this geometry for dissipative fixed-point engineering of unique target states be they pure or mixed. We extend capabilities by combining coherent control with simplest noise controls. Particular light is shed on reachability and open-loop versus closed-loop control design.
1972-01-01
Analytical models are presented for optimal trajectories and reentry guidance of the space shuttle orbiter. Major emphasis is placed on the development of a "footprint', which refers to a set of reachable destination positions attainable by the shuttle at a specified terminal altitude. An unconstrained reentry footprint was calculated for a shuttle vehicle which enters the earth's atmosphere at 93 km initial altitude after a deboost from a near earth orbit. The method of computation is briefly described, and graphs are presented which illustrate the footprint and the variation of state and control variables along it. The effects of constraints and of variations in initial state upon the footprint are discussed.
DEFF Research Database (Denmark)
Mailund, Thomas
The thesis describes the sweep-line method, a newly developed reduction method for alleviating the state explosion problem inherent in explicit-state state space exploration. The basic idea underlying the sweep-line method is, when calculating the state space, to recognise and delete states...... that are not reachable from the currently unprocessed states. Intuitively we drag a sweep-line through the state space with the invariant that all states behind the sweep-line have been processed and are unreachable from the states in front of the sweep-line. When calculating the state space of a system we iteratively...
Optimization-Based Layout Design
Directory of Open Access Journals (Sweden)
K. Abdel-Malek
2005-01-01
Full Text Available The layout problem is of importance to ergonomists, vehicle/cockpit packaging engineers, designers of manufacturing assembly lines, designers concerned with the placement of levers, knobs, controls, etc. in the reachable workspace of a human, and also to users of digital human modeling code, where digital prototyping has become a valuable tool. This paper proposes a hybrid optimization method (gradient-based optimization and simulated annealing to obtain the layout design. We implemented the proposed algorithm for a project at Oral-B Laboratories, where a manufacturing cell involves an operator who handles three objects, some with the left hand, others with the right hand.
Comparison Of Conventional And Recycled “Green” Office Paper
Directory of Open Access Journals (Sweden)
Klemen Možina
2011-05-01
Full Text Available To confront with the market need, we have to find alternative in respond to enormous necessity and application ofoffice paper. Therefore, one way in dealing with the problem is to replace or just decrease the use of paper madeentirely from primary components, mainly wood fibbers (deciduous and conifer. We analysed mechanical, optical,structural and microscopic properties. Experiments were performed on three conventional and three recycled officepapers reachable on the market. Results, obtained from measurements, confirm presumption, that mechanical andsurface properties of recycled office paper can be collated and they discern from conventional office paper.
Requirements for an Aircraft Carrier Flight Deck Fire Fighting Test Facility
2007-11-02
PEO Carriers 614 Sicard Street SE Stop 7007 11. SPONSOR / MONITOR’S REPORT Washington Navy Yard DC 20376-7007 NUMBER(S) 12. DISTRIBUTION /AVAILABILITY...nozzles are installed every 8 feet (alternately 5 feet and 3 feet apart). > Every point on the flight deck must be reachable by a minimum of two AFFF...nozzle rated at 125 gpm. > AFFF solution flow rates for each flight deck demand point are as follows: AFFF System Nominal Flow Rate Flush Deck/Deck Edge
Music Therapy as a Way to Enhance Lucidity in Persons with Dementia in Advanced Stages
DEFF Research Database (Denmark)
Ridder, Hanne Mette Ochsner
2005-01-01
Instead of describing dementia as a permanent state of non-lucidity, where the person is not reasonable and reachable, dementia is described as a condition where periods of confusion and dimness might alternate with clear and lucid mental states. In these states, the person with dementia is present...... and attentive and is able to interact with others. Theories of person-centred care give a basis of ideas that focus on personhood and see psychosocial needs as important in order to establish a caring environment. The use of songs in individual music therapy is applied to illustrate an approach that enhances...
Pointing with a One-Eyed Cursor for Supervised Training in Minimally Invasive Robotic Surgery
DEFF Research Database (Denmark)
Kibsgaard, Martin; Kraus, Martin
2016-01-01
Pointing in the endoscopic view of a surgical robot is a natural and effcient way for instructors to communicate with trainees in robot-assisted minimally invasive surgery. However, pointing in a stereo-endoscopic view can be limited by problems such as video delay, double vision, arm fatigue......, and reachability of the pointer controls. We address these problems by hardware-based overlaying the stereo-endoscopic view with a one-eyed cursor, which can be comfortably controlled by a wireless, gyroscopic air mouse. The proposed system was positively evaluated by five experienced instructors in four full......-day training units in robot- assisted minimally invasive surgery on anaesthetised pigs....
Towards Automatic Analysis of Election Verifiability Properties
Smyth, Ben; Ryan, Mark; Kremer, Steve; Kourjieh, Mounira
We present a symbolic definition that captures some cases of election verifiability for electronic voting protocols. Our definition is given in terms of reachability assertions in the applied pi calculus and is amenable to automated reasoning using the software tool ProVerif. The definition distinguishes three aspects of verifiability, which we call individual, universal, and eligibility verifiability. We demonstrate the applicability of our formalism by analysing the protocols due to Fujioka, Okamoto & Ohta and a variant of the one by Juels, Catalano & Jakobsson (implemented as Civitas by Clarkson, Chong & Myers).
DEFF Research Database (Denmark)
David, Alexandre; Larsen, Kim Guldstrand; Behrmann, Gerd
2006-01-01
In 2005 we proposed the first efficient on-the-fly algorithm for solving games based on timed game automata with respect to reachability and safety properties. Since then we have completely re-implemented the first prototype and made dramatic improvements both in terms of performance (several ord...... orders of magnitude) and the input language (complete support of all the language features of UPPAAL). In addition, the tool supports the new feature of strategy generation with different compactness levels. In this paper we present this new version of UPPAAL-Tiga....
Design and Simulation of a Feedback Control System for a Steel Plate Storage
Institute of Scientific and Technical Information of China (English)
Torben; Feld; Holmgaard; Kristensen; Hans; Holm; Jesper; Hansen
2002-01-01
A discrete event heuristic feedback control system fo r a steel plate storage at Odense Steel Shipyard Ltd is developed and implemente d in a computer-based simulation model. The plant is subject to stochastic dist urbances. The control system is able to handle this stochastic behaviour bec ause of the feedback design. The present simulation results indicate that a bene fit in the range of 30%～40% is reachable by modifying the plant. Plant description The steel plate storage is located at Odense Steel ...
An SPN analysis method for parallel scheduling in Ad Hoc networks
Institute of Scientific and Technical Information of China (English)
盛琳阳; 徐文超; 贾世楼
2004-01-01
In this paper, a new analytic method for modeling and evaluating mobile ad hoc networks (MANET)is proposed. Petri nets technique is introduced into MANET and a packet-flow parallel scheduling scheme is presented using Stochastic Petri Nets (SPN). The flowing of tokens is used in graphics mode to characterize dynamical features of sharing a single wireless channel. Through SPN reachability analysis and isomorphic continuous time Markov process equations, some network parameters, such as channel efficiency, one-hop transmission delay etc. , can be obtained. Compared with conventional performance evaluation methods, the above parameters are mathematical expressions instead of test results from a simulator.
A Model for Slicing JAVA Programs Hierarchically
Institute of Scientific and Technical Information of China (English)
Bi-Xin Li; Xiao-Cong Fan; Jun Pang; Jian-Jun Zhao
2004-01-01
Program slicing can be effectively used to debug, test, analyze, understand and maintain objectoriented software. In this paper, a new slicing model is proposed to slice Java programs based on their inherent hierarchical feature. The main idea of hierarchical slicing is to slice programs in a stepwise way, from package level, to class level, method level, and finally up to statement level. The stepwise slicing algorithm and the related graph reachability algorithms are presented, the architecture of the Java program Analyzing Tool (JATO) based on hierarchical slicing model is provided, the applications and a small case study are also discussed.
Provenance Storage, Querying, and Visualization in PBase
Energy Technology Data Exchange (ETDEWEB)
Kianmajd, Parisa [University of California, Davis; Ludascher, Bertram [University of California, Davis; Missier, Paolo [Newcastle University, UK; Chirigati, Fernando [New York University; Wei, Yaxing [ORNL; Koop, David [New York University; Dey, Saumen [University of California, Davis
2015-01-01
We present PBase, a repository for scientific workflows and their corresponding provenance information that facilitates the sharing of experiments among the scientific community. PBase is interoperable since it uses ProvONE, a standard provenance model for scientific workflows. Workflows and traces are stored in RDF, and with the support of SPARQL and the tree cover encoding, the repository provides a scalable infrastructure for querying the provenance data. Furthermore, through its user interface, it is possible to: visualize workflows and execution traces; visualize reachability relations within these traces; issue SPARQL queries; and visualize query results.
Optimizing Design Parameters for Sets of Concentric Tube Robots using Sampling-based Motion Planning
Baykal, Cenk; Torres, Luis G.; Alterovitz, Ron
2015-01-01
Concentric tube robots are tentacle-like medical robots that can bend around anatomical obstacles to access hard-to-reach clinical targets. The component tubes of these robots can be swapped prior to performing a task in order to customize the robot’s behavior and reachable workspace. Optimizing a robot’s design by appropriately selecting tube parameters can improve the robot’s effectiveness on a procedure-and patient-specific basis. In this paper, we present an algorithm that generates sets ...
Unification & sharing in timed automata verification
DEFF Research Database (Denmark)
David, Alexandre; Behrmann, Gerd; Larsen, Kim Guldstrand
2003-01-01
We present the design of the model-checking engine and internal data structures for the next generation of UPPAAL. The design is based on a pipeline architecture where each stage represents one independent operation in the verification algorithms. The architecture is based on essentially one shared...... data structure to reduce redundant computations in state exploration, which unifies the so-called passed and waiting lists of the traditional reachability algorithm. In the implementation, instead of using standard memory management functions from general-purpose operating systems, we have developed...
Control and estimation of piecewise affine systems
Xu, Jun
2014-01-01
As a powerful tool to study nonlinear systems and hybrid systems, piecewise affine (PWA) systems have been widely applied to mechanical systems. Control and Estimation of Piecewise Affine Systems presents several research findings relating to the control and estimation of PWA systems in one unified view. Chapters in this title discuss stability results of PWA systems, using piecewise quadratic Lyapunov functions and piecewise homogeneous polynomial Lyapunov functions. Explicit necessary and sufficient conditions for the controllability and reachability of a class of PWA systems are
Optimal scheduling using priced timed automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2005-01-01
This contribution reports on the considerable effort made recently towards extending and applying well-established timed automata technology to optimal scheduling and planning problems. The effort of the authors in this direction has to a large extent been carried out as part of the European...... projects VHS [20] and AMETIST [16] and are available in the recently released UPPAAL CORA [12], a variant of the real-time verification tool UPPAAL [18, 5] specialized for cost-optimal reachability for the extended model of so-called priced timed automata....
Asymptotic behavior of dynamical and control systems under perturbation and discretization
Grüne, Lars
2002-01-01
This book provides an approach to the study of perturbation and discretization effects on the long-time behavior of dynamical and control systems. It analyzes the impact of time and space discretizations on asymptotically stable attracting sets, attractors, asumptotically controllable sets and their respective domains of attractions and reachable sets. Combining robust stability concepts from nonlinear control theory, techniques from optimal control and differential games and methods from nonsmooth analysis, both qualitative and quantitative results are obtained and new algorithms are developed, analyzed and illustrated by examples.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
[ 篇名 ] Dynamics of the maneuvering vehicle IKAR control system by the orbital placement of globalstar satellites，[篇名 ] Information Sets in the Problem of Observation of Aircraft Motion in a Horizontal Plane，[ 篇名 ] Nonlinear control of a magnetic bearing system，[ 篇名 ] Power system transient stability enhancement by STATCOM with nonlinear control system，[ 篇名 ] Selecting operating points for discrete-time gain scheduling，[篇名] Stability analysis of nonlinear control systems with fuzzy DMC controllers，[篇名] Three-dimensional reachability set for a nonlinear control system， [ 篇名 ] Wheel slip control in ABS brakes using gain-scheduled constrained LQR 。
Secure neighborhood discovery: A fundamental element for mobile ad hoc networking
DEFF Research Database (Denmark)
Papadimitratos, P.; Poturalski, M.; Schaller, P.
2008-01-01
) - the discovery of devices directly reachable for communication or in physical proximity - becomes a fundamental requirement and building block for various applications. However, the very nature of wireless mobile networks makes it easy to abuse ND and thereby compromise the overlying protocols and applications......Pervasive computing systems will likely be deployed in the near future, with the proliferation of wireless devices and the emergence of ad hoc networking as key enablers. Coping with mobility and the volatility of wireless communications in such systems is critical. Neighborhood discovery (ND...
Maintenance of the CERN telephone exchanges
2007-01-01
Maintenance work will be carried out on the CERN telephone exchanges between 8 p.m. and midnight on 20 November. Fixed-line telephone and audioconference services may be disrupted while the work is being carried out. However, the CCC and the fire brigade will be reachable at any time. Mobile telephony services (GSM) will not be affected by the maintenance work. For further details about the maintenance work, please contact the telephone switchboard on 76111 or by email. Telecom Section - IT/CS
DEFF Research Database (Denmark)
Westergaard, Michael
2006-01-01
This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachability...... analysis of this net class, and an application of game coloured Petri nets to automatically generate easy-to-understand visualizations of the model by exploiting the knowledge that some parts of the model are not interesting from a visualization perspective (i.e. they are part of the environment...
Ion Pair in Extreme Aqueous Environments, Molecular-Based and Electric Conductance Approaches
Energy Technology Data Exchange (ETDEWEB)
Chialvo, Ariel A [ORNL; Gruszkiewicz, Miroslaw {Mirek} S [ORNL; Simonson, J Michael {Mike} [ORNL; Palmer, Donald [ORNL; Cole, David R [ORNL
2009-01-01
We determine by molecular-based simulation the density profiles of the Na+!Cl! ion-pair association constant in steam environments along three supercritical isotherms to interrogate the behavior of ion speciation in dilute aqueous solutions at extreme conditions. Moreover, we describe a new ultra-sensitive flow-through electric conductance apparatus designed to bridge the gap between the currently lowest steam-density conditions at which we are experimentally able to attain electric conductance measurements and the theoretically-reachable zero-density limit. Finally, we highlight important modeling challenges encountered near the zero-density limit and discuss ways to overcome them.
An Analysis of the Inverse Kinematics for a 5-DOF Manipulator
Institute of Scientific and Technical Information of China (English)
De Xu; Carlos A.Acosta Calderon; John Q.Gan; Huosheng Hu; Min Tan
2005-01-01
This paper proposes an analytical solution for a 5-DOF manipulator to follow a given trajectory while keeping the orientation of one axis in the end-effector frame. The forward kinematics and inverse kinematics for a 5-DOF manipulator are analyzed systemically. The singular problem is discussed after the forward kinematics is provided. For any given reachable position and orientation of the end-effector, the derived inverse kinematics will provide an accurate solution. In other words,there exists no singular problem for the 5-DOF manipulator, which has wide application areas such as welding, spraying,and painting. Experiment results verify the effectiveness of the methods developed in this paper.
Energy Technology Data Exchange (ETDEWEB)
Erdmenger, Christoph; Hermann, Hauke; Tambke, Jens (and others)
2007-06-15
The report covers the following chapters: executive summary: the eight most important measures for climate protection; introduction: why should Germany reduce its greenhouse gas emissions by 40% until 2020? Which framework requirements and assumptions are the basis for the Federal environmental Agency assessment? How should the required CO{sub 2} emission reduction be distributed to different sections? Which cost efficient measures can be reached in Germany: energy management, industry, households and business, traffic? Which instruments should be used in Germany? Conclusion: the 40% aim is reachable, but only with a resolute climate and energy policy.
Eisemann, Elmar; Assarsson, Ulf; Wimmer, Michael
2011-01-01
Important elements of games, movies, and other computer-generated content, shadows are crucial for enhancing realism and providing important visual cues. In recent years, there have been notable improvements in visual quality and speed, making high-quality realistic real-time shadows a reachable goal. Real-Time Shadows is a comprehensive guide to the theory and practice of real-time shadow techniques. It covers a large variety of different effects, including hard, soft, volumetric, and semi-transparent shadows.The book explains the basics as well as many advanced aspects related to the domain
Synthesis for PCTL in Parametric Markov Decision Processes
DEFF Research Database (Denmark)
Hahn, Ernst Moritz; Han, Tingting; Zhang, Lijun
2011-01-01
In parametric Markov decision processes (PMDPs), transition probabilities are not fixed, but are given as functions over a set of parameters. A PMDP denotes a family of concrete MDPs. This paper studies the synthesis problem for PCTL in PMDPs: Given a specification Φ in PCTL, we synthesise...... by hyper-rectangles, we allow a limited area to remain undecided. We also consider an extension of PCTL with reachability rewards. To demonstrate the applicability of the approach, we apply our technique on a case study, using a preliminary implementation....
DEFF Research Database (Denmark)
Behrmann, Gerd; Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2004-01-01
This contribution reports on the considerable effort made recently towards extending and applying well-established timed automata technology to optimal scheduling and planning problems. The effort of the authors in this direction has to a large extent been carried out as part of the European proj...... projects VHS [22] and AMETIST [17] and are available in the recently released UPPAAL CORA [12], a variant of the real-time verification tool UPPAAL [20,5] specialized for cost-optimal reachability for the extended model of priced timed automata....
Optimal scheduling using priced timed automata
DEFF Research Database (Denmark)
Behrmann, Gerd; Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2005-01-01
This contribution reports on the considerable effort made recently towards extending and applying well-established timed automata technology to optimal scheduling and planning problems. The effort of the authors in this direction has to a large extent been carried out as part of the European proj...... projects VHS [20] and AMETIST [16] and are available in the recently released UPPAAL CORA [12], a variant of the real-time verification tool UPPAAL [18, 5] specialized for cost-optimal reachability for the extended model of so-called priced timed automata....
Connectivity analysis of one-dimensional ad-hoc networks
DEFF Research Database (Denmark)
Bøgsted, Martin; Rasmussen, Jakob Gulddahl; Schwefel, Hans-Peter
2011-01-01
Application and communication protocols in dynamic ad-hoc networks are exposed to physical limitations imposed by the connectivity relations that result from mobility. Motivated by vehicular freeway scenarios, this paper analyzes a number of important connectivity metrics for instantaneous...... snapshots of stochastic geographic movement patterns: (1) The single-hop connectivity number, corresponding to the number of single-hop neighbors of a mobile node; (2) the multi-hop connectivity number, expressing the number of nodes reachable via multi-hop paths of arbitrary hop-count; (3) the connectivity...
Thermodynamic analysis and optimization of a high temperature triple absorption heat transformer.
Khamooshi, Mehrdad; Parham, Kiyan; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana; Babadi, Saeed
2014-01-01
First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle.
Study of the response of ATLAS electromagnetic liquid argon calorimeters to muons
Energy Technology Data Exchange (ETDEWEB)
Schwemling, P.; Lanni, F.; Aharrouche, M.; Colas, J.; Di Ciaccio, L.; El Kacimi, M.; Gaumer, O.; Gouanere, M.; Goujdami, D.; Lafaye, R.; Laplace, S.; Le Maner, C.; Neukermans, L.; Perrodo, P.; Poggioli, L.; Prieur, D.; Przysiezniak, H.; Sauvage, G.; Wingerter-Seez, I.; Zitoun, R.; Lanni, F.; Ma, H.; Rajagopalan, S.; Rescia, S.; Takai, H.; Belymam, A.; Benchekroun, D.; Hakimi, M.; Hoummada, A.; Gao, Y.; Lu, L.; Stroynowski, R.; Aleksa, M.; Carli, T.; Fassnacht, P.; Gianotti, F.; Hervas, L.; Lampl, W.; Collot, J.; Hostachy, J.Y.; Ledroit-Guillon, F.; Malek, F.; Martin, P.; Viret, S.; Leltchouk, M.; Parsons, J.A.; Simion, S.; Barreiro, F.; DelPeso, J.; Labarga, L.; Oliver, C.; Rodier, S.; Barrillon, P.; Djama, F.; Hubaut, F.; Mangeard, P.S.; Monnier, E.; Niess, V.; Pralavorio, P.; Resende, B.; Sauvage, D.; Serfon, C.; Tisserant, S.; Toth, J.; Zhang, H.; Banfi, D.; Carminati, L.; Cavalli, D.; Costa, G.; Delmastro, M.; Fanti, M.; Mandelli, L.; Mazzanti, M.; Tartarelli, G.F.; Kotov, K.; Maslennikov, A.; Pospelov, G.; Tikhonov, Yu.; Bourdarios, C.; Fayard, L.; Fournier, D.; Iconomidou-Fayard, L.; Kado, M.; Parrour, G.; Plamondon, M.; Puzo, P.; Rousseau, D.; Sacco, R.; Serin, L.; Unal, G.; Zerwas, D.; Dekhissi, B.; Derkaoui, J.; El Kharrim, A.; Maaroufi, F.; Cleland, W.; Lacour, D.; Laforge, B.; Nikolic-Audit, I.; Schwemling, Ph.; Ghazlane, H.; Cherkaoui El Moursli, R.; Idrissi Fakhr-Eddine, A.; Boonekamp, M.; Mansoulie, B.; Meyer, P.; Schwindling, J.; Lund-Jensen,B.; Tayalat, Y.
2009-01-01
The response of the ATLAS electromagnetic calorimeter to muons has been studied in this paper. Results on signal over noise ratio, assessment of the detector response uniformity, and position resolution are presented. The possibility to study fine details of the structure of the detector through its response to muons is illustrated on a specific example. Finally, the performance obtained on muons in test-beam is used to estimate the detector uniformity and time alignment precision that will be reachable after the commissioning of the ATLAS detector with cosmic rays.
DEFF Research Database (Denmark)
Mailund, Thomas
The thesis describes the sweep-line method, a newly developed reduction method for alleviating the state explosion problem inherent in explicit-state state space exploration. The basic idea underlying the sweep-line method is, when calculating the state space, to recognise and delete states...... that are not reachable from the currently unprocessed states. Intuitively we drag a sweep-line through the state space with the invariant that all states behind the sweep-line have been processed and are unreachable from the states in front of the sweep-line. When calculating the state space of a system we iteratively...
Parametrised Constants and Replication for Spatial Mobility
DEFF Research Database (Denmark)
Hüttel, Hans; Haagensen, Bjørn
2009-01-01
of reachable sites is static an encoding exists, but we also show that parametrised constants can not be encoded in the full calculus. The locality requirement supplements widely accepted encoding criteria. It appears to be a natural property in spatial calculi where links and locations can fail. The versions...... and the calculus of mobile ambients. Here, processes are located at sites and can migrate between them. In this paper we say that an encoding is local if it does not introduce extra migration. We first study this property for the distributed π-calculus where locations can be dynamically created. If the set...
A verification environment for bigraphs
DEFF Research Database (Denmark)
Perrone, Gian David; Debois, Søren; Hildebrandt, Thomas
2013-01-01
We present the BigMC tool for bigraphical reactive systems that may be instantiated as a verification tool for any formalism or domain-specific modelling language encoded as a bigraphical reactive system. We introduce the syntax and use of BigMC, and exemplify its use with two small examples......: a textbook “philosophers” example, and an example motivated by a ubiquitous computing application. We give a tractable heuristic with which to approximate interference between reaction rules, and prove this analysis to be safe. We provide a mechanism for state reachability checking of bigraphical reactive...
Synthesis of controllers for symmetric systems
Ameur Abid, Chiheb; Zouari, Belhassen
2010-11-01
This article deals with supervisory control problem for coloured Petri (CP) nets. Considering a CP-net, we build a condensed version of the ordinary state-space, namely the symbolic reachability graph (SRG). This latter graph allows to cope with state-space explosion problem for symmetric systems. The control specification can be expressed in terms of either forbidden states or forbidden sequences of transitions. According to these specifications, we derive the controller by applying the theory of regions on the basis of the SRG. Thanks to expressiveness power of CP-nets, the obtained controller to be connected to the plant model is reduced to one single place.
Kick-off Note on Possible Emergence Time of Newton Gravity
Diósi, Lajos
2012-01-01
If gravity were an emergent phenomenon, some relativistic as well as non-relativistic speculations claim it is, then a certain emergence time scale tau_? would characterize it. We argue that both astronomic and laboratory evidences have poor time resolution regarding how immediate the creation of Newton field of accelerating mass sources is. The current upper limit on tau_? is perhaps not stronger than 1s. Although the concrete theoretical model of gravity's `laziness' is missing, the concept might be tested directly in reachable experiments.
SPECT/CT helps in localization and guiding management of small bowel gastrointestinal hemorrhage.
Bentley, Brian S; Tulchinsky, Mark
2014-01-01
A 59-year-old female patient was hospitalized with anemia from recurrent gastrointestinal bleeding. Planar (99m)Tc-tagged red blood cell bleeding scan suggested an active site of low-rate hemorrhage in the left upper quadrant, but after 60 minutes it could not conclusively define the bleeding as originating in small versus large bowel. SPECT/CT unequivocally localized the hemorrhage to the small bowel and deemed it reachable by extended version ("push"’) endoscope. Subsequent push enteroscopy confirmed the bleeding in proximal jejunum and allowed effective treatment with electrocautery.
Verifying Time Petri Nets by Linear Programming
Institute of Scientific and Technical Information of China (English)
李宣东
2001-01-01
The paper proposes an approach to solving some verification problems of time Petri nets using linear programming. The approach is based on the observation that for loop-closed time Petri nets, it is only necessary to investigate a finite prefix of an untimed run of the underlying Petri net. Using the technique the paper gives solutions to reachability and bounded delay timing analysis problems. For both problems algorithms are given, that are decision procedures for loop-closed time Petri nets, and semi-decision procedures for general time Petri nets.
Convexity of the Set of Fixed Points Generated by Some Control Systems
Directory of Open Access Journals (Sweden)
Vadim Azhmyakov
2009-01-01
Full Text Available We deal with an application of the fixed point theorem for nonexpansive mappings to a class of control systems. We study closed-loop and open-loop controllable dynamical systems governed by ordinary differential equations (ODEs and establish convexity of the set of trajectories. Solutions to the above ODEs are considered as fixed points of the associated system-operator. If convexity of the set of trajectories is established, this can be used to estimate and approximate the reachable set of dynamical systems under consideration. The estimations/approximations of the above type are important in various engineering applications as, for example, the verification of safety properties.
Multiphase modeling of geologic carbon sequestration in saline aquifers.
Bandilla, Karl W; Celia, Michael A; Birkholzer, Jens T; Cihan, Abdullah; Leister, Evan C
2015-01-01
Geologic carbon sequestration (GCS) is being considered as a climate change mitigation option in many future energy scenarios. Mathematical modeling is routinely used to predict subsurface CO2 and resident brine migration for the design of injection operations, to demonstrate the permanence of CO2 storage, and to show that other subsurface resources will not be degraded. Many processes impact the migration of CO2 and brine, including multiphase flow dynamics, geochemistry, and geomechanics, along with the spatial distribution of parameters such as porosity and permeability. In this article, we review a set of multiphase modeling approaches with different levels of conceptual complexity that have been used to model GCS. Model complexity ranges from coupled multiprocess models to simplified vertical equilibrium (VE) models and macroscopic invasion percolation models. The goal of this article is to give a framework of conceptual model complexity, and to show the types of modeling approaches that have been used to address specific GCS questions. Application of the modeling approaches is shown using five ongoing or proposed CO2 injection sites. For the selected sites, the majority of GCS models follow a simplified multiphase approach, especially for questions related to injection and local-scale heterogeneity. Coupled multiprocess models are only applied in one case where geomechanics have a strong impact on the flow. Owing to their computational efficiency, VE models tend to be applied at large scales. A macroscopic invasion percolation approach was used to predict the CO2 migration at one site to examine details of CO2 migration under the caprock.
Directory of Open Access Journals (Sweden)
Tina Iachini
Full Text Available BACKGROUND: Do peripersonal space for acting on objects and interpersonal space for interacting with con-specifics share common mechanisms and reflect the social valence of stimuli? To answer this question, we investigated whether these spaces refer to a similar or different physical distance. METHODOLOGY: Participants provided reachability-distance (for potential action and comfort-distance (for social processing judgments towards human and non-human virtual stimuli while standing still (passive or walking toward stimuli (active. PRINCIPAL FINDINGS: Comfort-distance was larger than other conditions when participants were passive, but reachability and comfort distances were similar when participants were active. Both spaces were modulated by the social valence of stimuli (reduction with virtual females vs males, expansion with cylinder vs robot and the gender of participants. CONCLUSIONS: These findings reveal that peripersonal reaching and interpersonal comfort spaces share a common motor nature and are sensitive, at different degrees, to social modulation. Therefore, social processing seems embodied and grounded in the body acting in space.
Turn-Based War Chess Model and Its Search Algorithm per Turn
Directory of Open Access Journals (Sweden)
Hai Nan
2016-01-01
Full Text Available War chess gaming has so far received insufficient attention but is a significant component of turn-based strategy games (TBS and is studied in this paper. First, a common game model is proposed through various existing war chess types. Based on the model, we propose a theory frame involving combinational optimization on the one hand and game tree search on the other hand. We also discuss a key problem, namely, that the number of the branching factors of each turn in the game tree is huge. Then, we propose two algorithms for searching in one turn to solve the problem: (1 enumeration by order; (2 enumeration by recursion. The main difference between these two is the permutation method used: the former uses the dictionary sequence method, while the latter uses the recursive permutation method. Finally, we prove that both of these algorithms are optimal, and we analyze the difference between their efficiencies. An important factor is the total time taken for the unit to expand until it achieves its reachable position. The factor, which is the total number of expansions that each unit makes in its reachable position, is set. The conclusion proposed is in terms of this factor: Enumeration by recursion is better than enumeration by order in all situations.
Directory of Open Access Journals (Sweden)
Christoph Wagner
2014-08-01
Full Text Available Formal reasoning about distributed algorithms (like Consensus typically requires to analyze global states in a traditional state-based style. This is in contrast to the traditional action-based reasoning of process calculi. Nevertheless, we use domain-specific variants of the latter, as they are convenient modeling languages in which the local code of processes can be programmed explicitly, with the local state information usually managed via parameter lists of process constants. However, domain-specific process calculi are often equipped with (unlabeled reduction semantics, building upon a rich and convenient notion of structural congruence. Unfortunately, the price for this convenience is that the analysis is cumbersome: the set of reachable states is modulo structural congruence, and the processes' state information is very hard to identify. We extract from congruence classes of reachable states individual state-informative representatives that we supply with a proper formal semantics. As a result, we can now freely switch between the process calculus terms and their representatives, and we can use the stateful representatives to perform assertional reasoning on process calculus models.
Liu, Xiaosong; Shan, Zebiao; Li, Yuanchun
2017-04-01
Pinpoint landing is a critical step in some asteroid exploring missions. This paper is concerned with the descent trajectory control for soft touching down on a small irregularly-shaped asteroid. A dynamic boundary layer based neural network quasi-sliding mode control law is proposed to track a desired descending path. The asteroid's gravitational acceleration acting on the spacecraft is described by the polyhedron method. Considering the presence of input constraint and unmodeled acceleration, the dynamic equation of relative motion is presented first. The desired descending path is planned using cubic polynomial method, and a collision detection algorithm is designed. To perform trajectory tracking, a neural network sliding mode control law is given first, where the sliding mode control is used to ensure the convergence of system states. Two radial basis function neural networks (RBFNNs) are respectively used as an approximator for the unmodeled term and a compensator for the difference between the actual control input with magnitude constraint and nominal control. To improve the chattering induced by the traditional sliding mode control and guarantee the reachability of the system, a specific saturation function with dynamic boundary layer is proposed to replace the sign function in the preceding control law. Through the Lyapunov approach, the reachability condition of the control system is given. The improved control law can guarantee the system state move within a gradually shrinking quasi-sliding mode band. Numerical simulation results demonstrate the effectiveness of the proposed control strategy.
Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing.
Directory of Open Access Journals (Sweden)
Maksim Kitsak
Full Text Available Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems (ASes. Due to privacy and other reasons the information about what route to use to reach devices within other ASes is not readily available to any given AS. The Border Gateway Protocol (BGP is responsible for discovering and distributing this reachability information to all ASes. Since the topology of the Internet is highly dynamic, all ASes constantly exchange and update this reachability information in small chunks, known as routing control packets or BGP updates. In the view of the quick growth of the Internet there are significant concerns with the scalability of the BGP updates and the efficiency of the BGP routing in general. Motivated by these issues we conduct a systematic time series analysis of BGP update rates. We find that BGP update time series are extremely volatile, exhibit long-term correlations and memory effects, similar to seismic time series, or temperature and stock market price fluctuations. The presented statistical characterization of BGP update dynamics could serve as a basis for validation of existing and developing better models of Internet interdomain routing.
Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing.
Kitsak, Maksim; Elmokashfi, Ahmed; Havlin, Shlomo; Krioukov, Dmitri
2015-01-01
Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems (ASes). Due to privacy and other reasons the information about what route to use to reach devices within other ASes is not readily available to any given AS. The Border Gateway Protocol (BGP) is responsible for discovering and distributing this reachability information to all ASes. Since the topology of the Internet is highly dynamic, all ASes constantly exchange and update this reachability information in small chunks, known as routing control packets or BGP updates. In the view of the quick growth of the Internet there are significant concerns with the scalability of the BGP updates and the efficiency of the BGP routing in general. Motivated by these issues we conduct a systematic time series analysis of BGP update rates. We find that BGP update time series are extremely volatile, exhibit long-term correlations and memory effects, similar to seismic time series, or temperature and stock market price fluctuations. The presented statistical characterization of BGP update dynamics could serve as a basis for validation of existing and developing better models of Internet interdomain routing.
Prediction of Instability Separation Modes and Its Application in Practical Dynamic Security Region
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The transient critical boundary of dynamic security region (DSR) can be approximated by a few hyper planes correlated with instability separation modes. A method to fast predict instability separation modes is proposed for DSR calculation in power injection space. The method identifies coherent generation groups by the developed K-medoids algorithm, taking a similarity matrix derived from the reachability Grammian as the index. As an experimental result, reachability Grammian matrices under local injections are approximately invariant. It indicates that the generator coherency identifications are nearly consistent for different injections. Then instability separation modes can be predicted at the normal operating point, while average initial acceleration is considered as the measure of the critical generator group to amend the error. Moreover, based on these predicted instability separation modes, a critical point search strategy for DSR calculation is illustrated in the reduced injection space of the critical generators. The proposed method was evaluated using New England Test System, and the computation accuracy and speed in determining the practical DSR were improve.
Directory of Open Access Journals (Sweden)
Lingfeng Sang
2014-01-01
Full Text Available For the high carrying capacity of the human-carrying walking chair robot, in this paper, 2-UPS+UP parallel mechanism is selected as the leg mechanism; then kinematics, workspace, control, and experiment of the leg mechanism are researched in detail. Firstly, design of the whole mechanism is described and degrees of freedom of the leg mechanism are analyzed. Second, the forward position, inverse position, and velocity of leg mechanism are studied. Third, based on the kinematics analysis and the structural constraints, the reachable workspace of 2-UPS+UP parallel mechanism is solved, and then the optimal motion workspace is searched in the reachable workspace by choosing the condition number as the evaluation index. Fourth, according to the theory analysis of the parallel leg mechanism, its control system is designed and the compound position control strategy is studied. Finally, in optimal motion workspace, the compound position control strategy is verified by using circular track with the radius 100 mm; the experiment results show that the leg mechanism moves smoothly and does not tremble obviously. Theory analysis and experiment research of the single leg mechanism provide a theoretical foundation for the control of the quadruped human-carrying walking chair robot.
Performance limits of binary annular phase masks codesigned for depth-of-field extension
Falcón, Rafael; Goudail, François; Kulcsár, Caroline; Sauer, Hervé
2017-06-01
We investigate the performance limits of hybrid imaging systems including annular binary phase masks optimized for depth-of-field (DoF) extension, as a function of the number of rings and the desired DoF range. The mask parameters are optimized taking into account deconvolution of the acquired raw image in the expression of the global performance of the imaging system. We prove that masks with a limited number of rings are sufficient to obtain near-optimal performance. Moreover, the best achievable image quality decreases as the required DoF range increases, so that for a given required image quality, the DoF extension reachable with binary phase masks is bounded. Finally, these conclusions are shown to be robust against different optical system aberrations and models of scene power spectral density. These results are important in practice to decide if annular binary phase masks are the relevant solution for a given imaging problem and for mask manufacturing, since the number and thickness of the rings reachable at affordable cost by technology are generally limited.
Tomkins, Daniel
2014-01-01
Tarjan\\'s famous linear time, sequential algorithm for finding the strongly connected components (SCCs) of a graph relies on depth first search, which is inherently sequential. Deterministic parallel algorithms solve this problem in logarithmic time using matrix multiplication techniques, but matrix multiplication requires a large amount of total work. Randomized algorithms based on reachability - the ability to get from one vertex to another along a directed path - greatly improve the work bound in the average case. However, these algorithms do not always perform well; for instance, Divide-and-Conquer Strong Components (DCSC), a scalable, divide-and-conquer algorithm, has good expected theoretical limits, but can perform very poorly on graphs for which the maximum reachability of any vertex is small. A related algorithm, MultiPivot, gives very high probability guarantees on the total amount of work for all graphs, but this improvement introduces an overhead that increases the average running time. This work introduces SCCMulti, a multi-pivot improvement of DCSC that offers the same consistency as MultiPivot without the time overhead. We provide experimental results demonstrating SCCMulti\\'s scalability; these results also show that SCCMulti is more consistent than DCSC and is always faster than MultiPivot.
Geometric and algebraic properties of minimal bases of singular systems
Karcanias, Nicos
2013-11-01
For a general singular system ? with an associated pencil T(S), a complete classification of the right polynomial vector pairs ?, connected with the ? rational vector space, is given according to the proper-nonproper property, characterising the relationship of the degrees of those two vectors. An integral part of the classification of right pairs is the development of the notions of canonical and normal minimal bases for ? and ? rational vector spaces, where R(s) is the state restriction pencil of ?. It is shown that the notions of canonical and normal minimal bases are equivalent; the first notion characterises the pure algebraic aspect of the classification, whereas the second is intimately connected to the real geometry properties and the underlying generation mechanism of the proper and nonproper state vectors ?. The results describe the algebraic and geometric dimensions of the invariant partitioning of the set of reachability indices of singular systems. The classification of all proper and nonproper polynomial vectors ? induces a corresponding classification for the reachability spaces to proper-nonproper and results related to the possible dimensions feedback-spectra assignment properties of them are also given. The classification of minimal bases introduces new feedback invariants for singular systems, based on the real geometry of polynomial minimal bases, and provides an extension of the standard theory for proper systems (Warren, M.E., & Eckenberg, A.E. (1975).
Orientation angle workspaces of planar serial three-link manipulators
Institute of Scientific and Technical Information of China (English)
DAI; Jian; S
2009-01-01
This paper presents a classification on the workspaces of planar serial three-link manipulators, that is, position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. Orientation angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position workspace. By introducing a virtual equivalent mechanism, reachable position workspace can be di- vided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths. The orientation angle workspace of extended groups, that is, two of the three link lengths equal, and the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link rela- tions.
Orientation angle workspaces of planar serial three-link manipulators
Institute of Scientific and Technical Information of China (English)
LI RuiQin; DAI Jian S
2009-01-01
This paper presents a classification on the workspaces of planar serial three-link manipulators, that is,position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. Orientation angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position workspace. By introducing a virtual equivalent mechanism, reachable position workspace can be divided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths.The orientation angle workspace of extended groups, that is, two of the three link lengths equal, end the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link relations.
Fault detection of flywheel system based on clustering and principal component analysis
Directory of Open Access Journals (Sweden)
Wang Rixin
2015-12-01
Full Text Available Considering the nonlinear, multifunctional properties of double-flywheel with closed-loop control, a two-step method including clustering and principal component analysis is proposed to detect the two faults in the multifunctional flywheels. At the first step of the proposed algorithm, clustering is taken as feature recognition to check the instructions of “integrated power and attitude control” system, such as attitude control, energy storage or energy discharge. These commands will ask the flywheel system to work in different operation modes. Therefore, the relationship of parameters in different operations can define the cluster structure of training data. Ordering points to identify the clustering structure (OPTICS can automatically identify these clusters by the reachability-plot. K-means algorithm can divide the training data into the corresponding operations according to the reachability-plot. Finally, the last step of proposed model is used to define the relationship of parameters in each operation through the principal component analysis (PCA method. Compared with the PCA model, the proposed approach is capable of identifying the new clusters and learning the new behavior of incoming data. The simulation results show that it can effectively detect the faults in the multifunctional flywheels system.
Fault detection of flywheel system based on clustering and principal component analysis
Institute of Scientific and Technical Information of China (English)
Wang Rixin; Gong Xuebing; Xu Minqiang; Li Yuqing
2015-01-01
Considering the nonlinear, multifunctional properties of double-flywheel with closed-loop control, a two-step method including clustering and principal component analysis is proposed to detect the two faults in the multifunctional flywheels. At the first step of the proposed algorithm, clustering is taken as feature recognition to check the instructions of‘‘integrated power and attitude control”system, such as attitude control, energy storage or energy discharge. These commands will ask the flywheel system to work in different operation modes. Therefore, the relationship of parameters in different operations can define the cluster structure of training data. Ordering points to identify the clustering structure (OPTICS) can automatically identify these clusters by the reachability-plot. K-means algorithm can divide the training data into the corresponding operations according to the reachability-plot. Finally, the last step of proposed model is used to define the rela-tionship of parameters in each operation through the principal component analysis (PCA) method. Compared with the PCA model, the proposed approach is capable of identifying the new clusters and learning the new behavior of incoming data. The simulation results show that it can effectively detect the faults in the multifunctional flywheels system.
Avoiding moving obstacles by deviation from a mobile robot`s nominal path
Energy Technology Data Exchange (ETDEWEB)
Tsoularis, A.; Kambhampati, C. [Univ. of Reading, Whiteknights (United Kingdom). Dept. of Cybernetics
1999-05-01
This paper deals with the problem of obstacle avoidance by deviation from the nominal path. Deviation is the only option available to the robot when the acceleration or deceleration plan on the nominal path fails to produce a viable avoidance strategy. The obstacle avoidance on the nominal path was dealt with in the authors` previous development, where the robot`s motion was only subject to an upper bound on its speed. When the robot has to deviate, its motion is subject to a maximum steering constraint and a maximum deviation constraint in addition to the maximum speed constraint. The problem is solved geometrically by identifying final states for the robot that are reachable, satisfy all the constraints, and guarantee collision avoidance. The final state-reachability conditions that the authors obtain in the process ensure that no unnecessary deviation plan is initiated. These conditions, along with the simplicity of the geometric arguments they employ, make the scheme an attractive option for on-line implementation. The only significant complexity arises when minimizing the performance index. They have suggested dynamic programming as an optimization took, but any other nonlinear optimization technique can be adopted.
Knowledge Representation Standards and Interchange Formats for Causal Graphs
Throop, David R.; Malin, Jane T.; Fleming, Land
2005-01-01
In many domains, automated reasoning tools must represent graphs of causally linked events. These include fault-tree analysis, probabilistic risk assessment (PRA), planning, procedures, medical reasoning about disease progression, and functional architectures. Each of these fields has its own requirements for the representation of causation, events, actors and conditions. The representations include ontologies of function and cause, data dictionaries for causal dependency, failure and hazard, and interchange formats between some existing tools. In none of the domains has a generally accepted interchange format emerged. The paper makes progress towards interoperability across the wide range of causal analysis methodologies. We survey existing practice and emerging interchange formats in each of these fields. Setting forth a set of terms and concepts that are broadly shared across the domains, we examine the several ways in which current practice represents them. Some phenomena are difficult to represent or to analyze in several domains. These include mode transitions, reachability analysis, positive and negative feedback loops, conditions correlated but not causally linked and bimodal probability distributions. We work through examples and contrast the differing methods for addressing them. We detail recent work in knowledge interchange formats for causal trees in aerospace analysis applications in early design, safety and reliability. Several examples are discussed, with a particular focus on reachability analysis and mode transitions. We generalize the aerospace analysis work across the several other domains. We also recommend features and capabilities for the next generation of causal knowledge representation standards.
Zip：An Algorithm Based on Loser Tree for Common Contacts Searching in Large Graphs
Institute of Scientific and Technical Information of China (English)
唐宏; 牟帅; 黄晋; 朱佳; 陈健; 丁蕊
2015-01-01
The problem of k-hop reachability between two vertices in a graph has received considerable attention in recent years. A substantial number of algorithms have been proposed with the goal of improving the searching eﬃciency of the k-hop reachability between two vertices in a graph. However, searching and traversing are challenging tasks, especially in large-scale graphs. Furthermore, the existing algorithms propounded by different scholars are not satisfactory in terms of feasibility and scalability when applied to different kinds of graphs. In this work, we propose a new algorithm, called Zip, in an attempt to eﬃciently determine the common contacts between any two random vertices in a large-scale graph. First, we describe a novel algorithm for constructing the graph index via binary searching which maintains the adjacent list of each vertex in order. Second, we present the ways to achieve a sequential k-hop contact set by using the loser tree, a merge sorting algorithm. Finally, we develop an eﬃcient algorithm for querying common contacts and an optimized strategy for k-hop contact set serialization. Experimental results on synthetic and real datasets show that the proposed Zip algorithm outperforms existing state-of-the-art algorithms (e.g., breadth-first searching, GRAIL, the graph stratification algorithm).
A Light-Weight Approach for Verifying Multi-Threaded Programs with CPAchecker
Directory of Open Access Journals (Sweden)
Dirk Beyer
2016-12-01
Full Text Available Verifying multi-threaded programs is becoming more and more important, because of the strong trend to increase the number of processing units per CPU socket. We introduce a new configurable program analysis for verifying multi-threaded programs with a bounded number of threads. We present a simple and yet efficient implementation as component of the existing program-verification framework CPAchecker. While CPAchecker is already competitive on a large benchmark set of sequential verification tasks, our extension enhances the overall applicability of the framework. Our implementation of handling multiple threads is orthogonal to the abstract domain of the data-flow analysis, and thus, can be combined with several existing analyses in CPAchecker, like value analysis, interval analysis, and BDD analysis. The new analysis is modular and can be used, for example, to verify reachability properties as well as to detect deadlocks in the program. This paper includes an evaluation of the benefit of some optimization steps (e.g., changing the iteration order of the reachability algorithm or applying partial-order reduction as well as the comparison with other state-of-the-art tools for verifying multi-threaded programs.
Lepton flavor violating Z decays: A promising window to low scale seesaw neutrinos
De Romeri, V; Marcano, X; Scarcella, F
2016-01-01
In this paper we study the Lepton Flavor Violating $Z$ boson decays $Z \\to \\tau \\mu$ and $Z \\to \\tau e$ in the context of low scale seesaw models with new heavy Majorana neutrinos whose masses could be reachable at the LHC. Our computations of the decay rates are done in the particular realization given by the Inverse Seesaw Model with six extra heavy neutrinos which are quasi-degenerate in three pseudo-Dirac pairs. In particular, we focus on scenarios that are built ad-hoc to produce suppressed rates in all the processes involving $\\mu$-$e$ transitions, given the fact that these are by far the most strongly constrained by present data. We will fully explore the $Z \\to \\tau \\mu$ and $Z \\to \\tau e$ rates, together with a set of observables that we find to be the most constraining ones, and we will conclude that sizable rates of up to $2 \\times 10^{-7}$, accessible at future colliders, can be reached in this model for Majorana masses in the few TeV range, potentially reachable at LHC.
SPARQL for a Web of Linked Data: Semantics and Computability (Extended Version)
Hartig, Olaf
2012-01-01
The World Wide Web currently evolves into a Web of Linked Data where content providers publish and link data as they have done with hypertext for the last 20 years. While the declarative query language SPARQL is the de facto for querying a-priory defined sets of data from the Web, no language exists for querying the Web of Linked Data itself. However, it seems natural to ask whether SPARQL is also suitable for such a purpose. In this paper we formally investigate the applicability of SPARQL as a query language for Linked Data on the Web. In particular, we study two query models: 1) a full-Web semantics where the scope of a query is the complete set of Linked Data on the Web and 2) a family of reachability-based semantics which restrict the scope to data that is reachable by traversing certain data links. For both models we discuss properties such as monotonicity and computability as well as the implications of querying a Web that is infinitely large due to data generating servers.
An algebraic approach to revising propositional rule-based knowledge bases
Institute of Scientific and Technical Information of China (English)
LUAN ShangMin; DAI GuoZhong
2008-01-01
One of the important topics in knowledge base revision is to introduce an efficient implementation algorithm. Algebraic approaches have good characteristics and implementation method; they may be a choice to solve the problem. An algebraic approach is presented to revise propositional rule-based knowledge bases in this paper. A way is firstly introduced to transform a propositional rule-based knowl- edge base into a Petri net. A knowledge base is represented by a Petri net, and facts are represented by the initial marking. Thus, the consistency check of a knowledge base is equivalent to the reachability problem of Petri nets. The reachability of Petri nets can be decided by whether the state equation has a solution; hence the con- sistency check can also be implemented by algebraic approach. Furthermore, al- gorithms are introduced to revise a propositional rule-based knowledge base, as well as extended logic programming. Compared with related works, the algorithms presented in the paper are efficient, and the time complexities of these algorithms are polynomial.
Iachini, Tina; Coello, Yann; Frassinetti, Francesca; Ruggiero, Gennaro
2014-01-01
Background Do peripersonal space for acting on objects and interpersonal space for interacting with con-specifics share common mechanisms and reflect the social valence of stimuli? To answer this question, we investigated whether these spaces refer to a similar or different physical distance. Methodology Participants provided reachability-distance (for potential action) and comfort-distance (for social processing) judgments towards human and non-human virtual stimuli while standing still (passive) or walking toward stimuli (active). Principal Findings Comfort-distance was larger than other conditions when participants were passive, but reachability and comfort distances were similar when participants were active. Both spaces were modulated by the social valence of stimuli (reduction with virtual females vs males, expansion with cylinder vs robot) and the gender of participants. Conclusions These findings reveal that peripersonal reaching and interpersonal comfort spaces share a common motor nature and are sensitive, at different degrees, to social modulation. Therefore, social processing seems embodied and grounded in the body acting in space. PMID:25405344
Neutron Capture Experiments on Unstable Nuclei
Energy Technology Data Exchange (ETDEWEB)
Jon M. Schwantes; Ralf Sudowe; Heino Nitsche; Darleane C. Hoffman
2003-12-16
containing about twenty times as much Sm. An exhaustive review of the literature indicated that a multiprocess approach in which Eu(III) is reduced to Eu(II) prior to separation should provide an effective and efficient means of separation from the Sm(III). To date, three multiprocess methods have been developed and tested for their ability to meet the design requirements set forth by this project. These methods combine an initial reduction step using Zn(Hg) with either cation exchange resin in (1) column form or in (2) a batch reactor and hydroxyisobutyrate (?-HIB) as the eluant for trivalent lanthanides. Another multiprocess method uses solvent extraction with 0.1 M thenoyl trifluoroacetone (TTA) in benzene. Preliminary experiments indicate that: (a) A multiprocess approach using ?-HIB as a complexing agent for trivalent lanthanides is ineffective for separating Eu from Sm because ?-HIB stabilizes Eu(III) even in the presence of excess amounts of the reductant; (b) A multiprocess approach using solvent extraction shows promise, indicating that 0.1 M TTA in benzene favors extraction of trivalent over divalent metal ions by a factor of greater than 750. However, the reduction step using Zn(Hg), when combined with the TTA extraction, becomes less effective at reducing Eu during subsequent extractions and may also affect the stability of the TTA. Use of the amalgam also introduces Zn(II) contamination that must be separated from the Eu with additional solvent extraction steps. A PhD student from the group has visited the LANSCE facility, participated in several parameter checks of the DANCE, and acquainted himself with the data acquisition system. During these initial experiments, data were collected and brought back to UC Berkeley for analysis. A high purity P-type germanium detector was purchased, set up, and calibrated to assist with the determination of separation yields and efficiencies using ?-ray spectroscopy measurements of suitable radioactive tracers.
Applications of the theory of computation to nanoscale self-assembly
Doty, David Samuel
. Finally, after showing these positive results, we turn our attention to negative results and investigate inherent limitations in the aTAM at "temperature 1", meaning roughly that all bonds in the system have sufficient strength to permanently attach tiles without help from other bonds (i.e., the temperature is too low to "shake off" any tiles, even those connected by a single bond). Specifically, we show that at temperature 1, a wide class of deterministic tile sets (those satisfying a natural condition known as "pumpability") form only the most computationally simple structures (specifically, semilinear sets of integer coordinates, equivalently those sets definable in Presburger arithmetic), and in particular are strictly less powerful than the computationally universal temperature 2 tile assembly model. We leave as an open question whether all deterministic temperature 1 tile sets are in fact pumpable.
Impairment-constrained network design in mixed line rate and flexible-grid optical networks
Xie, Weisheng
Mixed line rate (MLR) and flexible-grid optical networks are two promising network paradigms for next generation optical networks. In MLR optical networks, different optical channels may operate at different line rates and use the same amount of spectrum. In flexible-grid optical networks, besides different line rates, different optical channels can use different amount of spectrum. In both MLR and flexible-grid optical networks, the physical layer impairments will impact the signal reachability and will require regenerator placement to restore the signal quality. Different line rates and modulation formats suffer from different levels of impairments, and thus have different reachabilities. In this dissertation, we study multiple network design problems with impairment constraints for both MLR and flexible-grid optical networks. We first study regenerator site (RS) selection problems in MLR optical networks. Given a network topology, set of requests, and different line rates' reachabilities, the problem is to select the minimum number of nodes in the network as RSs. We divide the topic into two separate research problems depending on whether routing is fixed or flexible. Energy efficiency is an important factor that will impact the operational expenditure of a telecom network. When designing the routing and wavelength assignment approach for a set of connection requests, the placement of regenerators needs to be considered in order to increase energy efficiency. In this work, we study how to place the minimum number of regenerators in MLR optical networks, while satisfying all the requests. Virtual optical network (VON) mapping plays a vital role in optical network virtualization. When mapping VONs, it is necessary to provision backup resources to guarantee survivability. Thus, we consider how to map VONs that can survive single link failures in flexible-grid optical networks. The objective is to minimize network equipment cost, including regenerators. We also
Institute of Scientific and Technical Information of China (English)
曹曦; 王洪涛; 刘玉田
2015-01-01
实际大规模输电网架恢复时间与空间跨度大,涉及操作众多,需要各级调度共同参与,因此提出一种网架恢复的分层协同优化方法.引入"受电点"的概念,将输电网架拆分,构建基于受电点指标约定的恢复协作机制,继而建立网架恢复的分层协同优化模型.该模型将主网架重构完成度与各地区新增发电量作为优化目标,采用分层次独立优化与受电点指标值整体寻优相结合的方法,可有效降低问题求解规模,并能够兼顾求解全局性与各层级的恢复偏好.通过受电点指标约定,明确任务分工与各地区的操作边界,能够实现有功、无功的协调控制与分层分区独立并行恢复,可显著提高恢复效率.山东电网实际算例验证了所提方法的有效性和实用性.%Network restoration after a widespread blackout involves complicated multi-process operations with a large spatial and temporal span, which needs the cooperation of multi-level dispatching centers. So a hierarchical collaborative optimization method for network restoration was proposed. The concept of feed point (FP) was introduced and the network restoration was divided into two layers. An FP based restoration cooperation mechanism was built. And then the collaborative optimization model was established. The objectives of this model are defined as network reconfiguration degree and total power production. The method combined hierarchical optimization with overall searching of the FP index value which makes the solving scale of the whole problem reduced dramatically. Global optimization and preference of each region can be obtained at the same time. The cooperation mechanism makes the task assignment clear. The coordination control of active/reactive power and multi-process parallel restoration operations can be achieved. The cases of Shandong power grid verify the effectiveness and practicability of this method.
The mobile phone (and texts) as a taken for granted mediation
DEFF Research Database (Denmark)
Ling, Richard
2014-01-01
-users were living outside the circle of social mediation. This meant that there was a type of social exclusion, and also that there was (and is) a social inefficiency when trying to organize social interaction. There is also a self-reflexive dimension. When working out our daily activities, we make...... at the movies is reachable beforehand so that we can micro-coordinate. If this form of mediation is not available, we may subject the person to mild forms of reproach. This indicates that the mobile telephone has become a social mediation technology that is taken for granted. Just as mechanical time keeping...... is taken for granted in our coordination of social interaction, mobile communication is now taking on some of the same dimensions....