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18
Scheduling Garbage Collection in Embedded Systems
, 1998
"... The complexity of systems for automatic control and other safetycritical applications grows rapidly. Computer software represents an increasing part of the complexity. As larger systems are developed, we need to find scalable techniques to manage the complexity in order to guarantee high product qu ..."
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Cited by 74 (0 self)
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The complexity of systems for automatic control and other safetycritical applications grows rapidly. Computer software represents an increasing part of the complexity. As larger systems are developed, we need to find scalable techniques to manage the complexity in order to guarantee high product quality. Memory management is a key quality factor for these systems. Automatic memory management, or garbage collection, is a technique that significantly reduces the complex problem of correct memory management. The risk of software errors decreases and development time is reduced. Garbage collection techniques suitable for interactive and soft realtime systems exist, but few approaches are suitable for systems with hard realtime requirements, such as control systems (embedded systems). One part of the problem is solved by incremental garbage collection algorithms, which have been presented before. We focus on the scheduling problem which forms the second part of the problem, i.e. how the work of a garbage collector should be scheduled in order
Coverage Preserving Reduction Strategies for Reachability Analysis
"... We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be ..."
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Cited by 59 (8 self)
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We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be explored for a full state space exploration. The third strategy is the implementation of a state compression scheme that attempts to minimize the amount of memory that is used to built a state space. The three strategies are shown to have a potential for substantially improving the performance of a conventional search. The paper discusses the optimal choices for reducing either run time or memory requirements by four to six times. The strategies can readily be combined with each other and with alternative state space reduction techniques such as supertrace or state space caching methods.
State Compression in SPIN: Recursive Indexing And Compression Training Runs
 IN PROCEEDINGS OF THIRD INTERNATIONAL SPIN WORKSHOP
, 1997
"... The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable statespace of a system that is obtained through the formalization of a correctness requirement as an automaton. This automaton restricts the statespace to precisely the subset that may contain ..."
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Cited by 42 (1 self)
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The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable statespace of a system that is obtained through the formalization of a correctness requirement as an automaton. This automaton restricts the statespace to precisely the subset that may contain the counterexamples to the original correctness requirement, if they exist. This method of verification conforms to the method for automatatheoretic verification outlined in [VW86]. SPIN derives
The Complexity of Automated Reasoning
, 1989
"... This thesis explores the relative complexity of proofs produced by the automatic theorem proving procedures of analytic tableaux, linear resolution, the connection method, tree resolution and the DavisPutnam procedure. It is shown that tree resolution simulates the improved tableau procedure and th ..."
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Cited by 9 (0 self)
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This thesis explores the relative complexity of proofs produced by the automatic theorem proving procedures of analytic tableaux, linear resolution, the connection method, tree resolution and the DavisPutnam procedure. It is shown that tree resolution simulates the improved tableau procedure and that SLresolution and the connection method are equivalent to restrictions of the improved tableau method. The theorem by Tseitin that the DavisPutnam Procedure cannot be simulated by tree resolution is given an explicit and simplified proof. The hard examples for tree resolution are contradictions constructed from simple Tseitin graphs.
Cops and robbers from a distance
 Theor. Comput. Sci
"... Abstract. Cops and Robbers is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robbers, distance k Cops and Robbers, where the cops win if at least one of them is of distance at most k from the robber in G. The cop number of a graph G ..."
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Cited by 1 (0 self)
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Abstract. Cops and Robbers is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robbers, distance k Cops and Robbers, where the cops win if at least one of them is of distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops needed to capture the robber in G. The distance k analogue of the cop number, written ck(G), equals the minimum number of cops needed to win at a given distance k. We study the parameter ck from algorithmic, structural, and probabilistic perspectives. We supply a classification result for graphs with bounded ck(G) values and develop an O(n2s+3) algorithm for determining if ck(G) ≤ s for s fixed. We prove that if s is not fixed, then computing ck(G) is NPhard. Upper and lower bounds are found for ck(G) in terms of the order of G. We prove that n
Pursuit and evasion from a distance: algorithms and bounds
"... Cops and Robber is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robber, distance k Cops and Robber, where the cops win if they are distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops ..."
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Cited by 1 (0 self)
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Cops and Robber is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robber, distance k Cops and Robber, where the cops win if they are distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops needed to capture the robber in G. The distance k analogue of the cop number, written ck(G), equals the minimum number of cops needed to win at a given distance k. We supply a classification result for graphs with bounded ck(G) values and develop an O(n2s+3) algorithm for determining if ck(G) ≤ s. In the case k = 0, our algorithm is faster than previously known algorithms. Upper and lower bounds are found for ck(G) in terms of the order of G. We prove that
Problem Solving Environments and Symbolic Computing
, 1997
"... ion, representation, communication : : : : : : : : : : 29 5.5 System and human interface design issues : : : : : : : : : : : 31 5.6 Miscellany : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 32 6 Acknowledgments 33 Abstract What role should be played by symbolic mathematical computation ..."
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Cited by 1 (0 self)
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ion, representation, communication : : : : : : : : : : 29 5.5 System and human interface design issues : : : : : : : : : : : 31 5.6 Miscellany : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 32 6 Acknowledgments 33 Abstract What role should be played by symbolic mathematical computation facilities in scientific and engineering "problem solving environments"? Most observers agree with us that in conjunction with numerical libraries and other facilities, symbolic computation should be useful for the creation and manipulation of mathematical models, the production of custom numerical software, and the solution of certains classes of mathematical problems that are difficult to handle by traditional floatingpoint computation. Even further, though, symbolic representation and manipulation can potentially play a more central role  with more general representations a program can naturally deal with computational objects of a more general nature. Numerical, graphical, and other...
Periodicities on Trees
, 1995
"... We introduce the notion of periodicity for kary labeled trees: roughly speaking, a tree is periodic if it can be obtained by a sequence of concatenations of a smaller tree plus a "remainder". The period is the shape of such smaller tree (i.e. the corresponding unlabeled tree). This defini ..."
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Cited by 1 (1 self)
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We introduce the notion of periodicity for kary labeled trees: roughly speaking, a tree is periodic if it can be obtained by a sequence of concatenations of a smaller tree plus a "remainder". The period is the shape of such smaller tree (i.e. the corresponding unlabeled tree). This definition reduces to the classical one for string when restricted to the case of unary trees. Then, we define the greatest common divisor of two unlabeled trees and relate right congruences to unlabeled trees. This allows us to give a characterization of tree periodicity in terms of right congruences and then to prove a periodicity theorem for trees that is a generalization to trees of the Fine and Wilf's periodicity theorem for words. Keywords: Congruence, periodicity, labeled tree. Work partially supported by the ESPRIT II Basic Research Actions Program of the EC under Project ASMICS 2 (contract No. 6317) and in part by the Italian Ministry of Universities and Scientific Research MURST 40% Algoritmi, ...
RIA: An RF Intereference Avoidance Algorithm for Heteregeneous Wireless Networks
, 2005
"... Due to the unlicensed nature of 2.4 GHz ISM band, the number of technologies using this band is growing. FCC regulations mandate that these technologies need to implement some form of frequency sharing. Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) are two pop ..."
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Due to the unlicensed nature of 2.4 GHz ISM band, the number of technologies using this band is growing. FCC regulations mandate that these technologies need to implement some form of frequency sharing. Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) are two popular techniques to share the frequencies within this band. However, devices implementing different technologies may cause interference; this problem is welldocumented as occurring with 802.11 (using DSSS) and Bluetooth (using FHSS). Designing an interference avoidance algorithm for combinations of these DSSS/FHSS based technologies is complex. In this paper, we focus on a simpler but very common case when these technologies are located within the same device. For this case, we propose a simple and novel algorithm called, Radio Interference Avoidance Algorithm, RIA, that solves the problem of interference between any arbitrary DSSS and FHSS technologies. In this paper we derive the expected value of response time for RIA. We then run simulations to demonstrate the effectiveness of RIA. Our results indicate that RIA is able to eliminate interference with a very small response time. RIA also outperforms Adaptive Frequency Hopping, a solution proposed by the IEEE 802.15 Coexistence Working Group.