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Multiclock timed networks
 In Proc.LICS' 04
, 2004
"... Abstract. We consider verification of safety properties for parameterized systems of timed processes, so called timed networks. A timed network consists of a finite state process, called a controller, and an arbitrary set of identical timed processes. In a previous work, we showed that checking safe ..."
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Cited by 10 (3 self)
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safety properties is decidable in the case where each timed process is equipped with a single realvalued clock. It was left open whether the result could be extended to multiclock timed networks. We show that the problem becomes undecidable when each timed process has two clocks. On the other hand, we
Time, Clocks, and the Ordering of Events in a Distributed System
, 1978
"... The concept of one event happening before another in a distributed system is examined, and is shown to define a partial ordering of the events. A distributed algorithm is given for synchronizing a system of logical clocks which can be used to totally order the events. The use of the total ordering i ..."
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Cited by 2869 (14 self)
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The concept of one event happening before another in a distributed system is examined, and is shown to define a partial ordering of the events. A distributed algorithm is given for synchronizing a system of logical clocks which can be used to totally order the events. The use of the total ordering
Clock Time is Absolute and Universal
"... ABSTRACTION A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the abstract STR time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks and al ..."
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ABSTRACTION A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the abstract STR time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks
CLOCK TIME AND ENTROPY
, 1993
"... 1. What is fundamental in a quantum description of the world? It is a matter of debate what the basic entities of the universe are in quantum theory. Expanding the metaphor used by Griffiths at this conference, one might imagine that the conversations of the three meals of the day could be restricte ..."
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1. What is fundamental in a quantum description of the world? It is a matter of debate what the basic entities of the universe are in quantum theory. Expanding the metaphor used by Griffiths at this conference, one might imagine that the conversations of the three meals of the day could be restricted to three possible answers: (a) Amplitudes (subject of lunch conversation). One might imagine formulating quantum theory in the morning and concluding at lunch that complex amplitudes were the fundamental entities. Each finegrained history hi might be assigned an amplitude A[hi] = e iS[hi], (1) where S[hi] is the action (in units of ¯h) of that history (Feynman and Hibbs 1965). The finegrained histories could then be combined into a weighted group of histories α (called a coarsegrained history) with amplitude A[α] = ∑ wα [hi]e iS[hi], (2) i where wα is an αdependent weight functional of the finegrained histories hi. For
Internet time synchronization: The network time protocol
, 1989
"... This memo describes the Network Time Protocol (NTP) designed to distribute time information in a large, diverse internet system operating at speeds from mundane to lightwave. It uses a returnabletime architecture in which a distributed subnet of time servers operating in a selforganizing, hierarchi ..."
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Cited by 628 (15 self)
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organizing, hierarchical, masterslave configuration synchronizes local clocks within the subnet and to national time standards via wire or radio. The servers can also redistribute time information within a network via local routing algorithms and time daemons. The architectures, algorithms and protocols which have
Virtual clock: A new traffic control algorithm for packet switching networks
 In Proc. ACM SIGCOMM
, 1990
"... A challenging research issue in high speed networking is how to control the transmission rate of statistical data P OWS. This paper describes a new algorithm, VirtualClock, for data trafic control in highspeed networks. VirtualClock maintains the statistical multiplexing flexibility of packet swit ..."
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Cited by 617 (4 self)
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A challenging research issue in high speed networking is how to control the transmission rate of statistical data P OWS. This paper describes a new algorithm, VirtualClock, for data trafic control in highspeed networks. VirtualClock maintains the statistical multiplexing flexibility of packet
A theory of timed automata
, 1999
"... Model checking is emerging as a practical tool for automated debugging of complex reactive systems such as embedded controllers and network protocols (see [23] for a survey). Traditional techniques for model checking do not admit an explicit modeling of time, and are thus, unsuitable for analysis of ..."
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Cited by 2651 (32 self)
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using finitely many realvalued clock variables. Automated analysis of timed automata relies on the construction of a finite quotient of the infinite space of clock valuations. Over the years, the formalism has been extensively studied leading to many results establishing connections to circuits
TimingSync Protocol for Sensor Networks
 The First ACM Conference on Embedded Networked Sensor System (SenSys
, 2003
"... Wireless adhoc sensor networks have emerged as an interesting and important research area in the last few years. The applications envisioned for such networks require collaborative execution of a distributed task amongst a large set of sensor nodes. This is realized by exchanging messages that are ..."
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Cited by 515 (8 self)
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that are timestamped using the local clocks on the nodes. Therefore, time synchronization becomes an indispensable piece of infrastructure in such systems. For years, protocols such as NTP have kept the clocks of networked systems in perfect synchrony. However, this new class of networks has a large density of nodes
Symbolic Model Checking for Realtime Systems
 INFORMATION AND COMPUTATION
, 1992
"... We describe finitestate programs over realnumbered time in a guardedcommand language with realvalued clocks or, equivalently, as finite automata with realvalued clocks. Model checking answers the question which states of a realtime program satisfy a branchingtime specification (given in an ..."
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Cited by 578 (50 self)
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We describe finitestate programs over realnumbered time in a guardedcommand language with realvalued clocks or, equivalently, as finite automata with realvalued clocks. Model checking answers the question which states of a realtime program satisfy a branchingtime specification (given
Virtual time and global states of distributed systems.
 Proc. Workshop on Parallel and Distributed Algorithms,
, 1989
"... Abstract A distributed system can be characterized by the fact that the global state is distributed and that a common time base does not exist. However, the notion of time is an important concept in every day life of our decentralized \ r eal world" and helps to solve problems like getting a c ..."
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Cited by 744 (5 self)
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consistent population census or determining the potential causality between events. We argue that a linearly ordered structure of time is not (always) adequate for distributed systems and propose a generalized nonstandard m o del of time which consists of vectors of clocks. These clockvectors are p
Results 1  10
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9,156