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Learnability in Optimality Theory
, 1995
"... In this article we show how Optimality Theory yields a highly general Constraint Demotion principle for grammar learning. The resulting learning procedure specifically exploits the grammatical structure of Optimality Theory, independent of the content of substantive constraints defining any given gr ..."
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Cited by 447 (33 self)
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In this article we show how Optimality Theory yields a highly general Constraint Demotion principle for grammar learning. The resulting learning procedure specifically exploits the grammatical structure of Optimality Theory, independent of the content of substantive constraints defining any given grammatical module. We decompose the learning problem and present formal results for a central subproblem, deducing the constraint ranking particular to a target language, given structural descriptions of positive examples. The structure imposed on the space of possible grammars by Optimality Theory allows efficient convergence to a correct grammar. We discuss implications for learning from overt data only, as well as other learning issues. We argue that Optimality Theory promotes confluence of the demands of more effective learnability and deeper linguistic explanation.
Deep Packet Inspection Using Parallel Bloom Filters
, 2004
"... this memory core, five randommemory locations are readable in a single clock cycle. So performing 35 concurrent memory operations requires seven parallel memory cores, each with oneseventh of the required array size, as Figure 5b illustrates. Because the basic Bloom filter allows any hash function ..."
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Cited by 174 (18 self)
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this memory core, five randommemory locations are readable in a single clock cycle. So performing 35 concurrent memory operations requires seven parallel memory cores, each with oneseventh of the required array size, as Figure 5b illustrates. Because the basic Bloom filter allows any hash function to map to any bit in the vector, it is possible that for some member, more than five hash functions map to the same memory segment, thereby exceeding the lookup capacity of this memory core. We can solve this problem by restricting the range of each hash function to a given memory, preventing memory contention
Eliminating Array Bound Checking Through Dependent Types
 In Proceedings of ACM SIGPLAN Conference on Programming Language Design and Implementation
, 1998
"... We present a typebased approach to eliminating array bound checking and list tag checking by conservatively extending Standard ML with a restricted form of dependent types. This enables the programmer to capture more invariants through types while typechecking remains decidable in theory and can s ..."
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Cited by 174 (24 self)
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We present a typebased approach to eliminating array bound checking and list tag checking by conservatively extending Standard ML with a restricted form of dependent types. This enables the programmer to capture more invariants through types while typechecking remains decidable in theory and can still be performed efficiently in practice. We illustrate our approach through concrete examples and present the result of our preliminary experiments which support support the feasibility and effectiveness of our approach. 1 Introduction The absence of runtime array bound checks is an infamous source of fatal errors for programs in languages such as C. Nonetheless, compilers offer the option to omit array bound checks, since they can turn out to be expensive in practice (Chow 1983; Gupta 1994). In statically typed languages such as ML, one would like to provide strong guarantees about the safety of all operations, so array bound checks cannot be omitted in general. The same is true for Ja...
Shortest path algorithms: An evaluation using real road networks
 Transportation Science
, 1998
"... The classic problem of finding the shortest path over a network has been the target of many research efforts over the years. These research efforts have resulted in a number of different algorithms and a considerable amount of empirical findings with respect to performance. Unfortunately, prior rese ..."
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Cited by 65 (1 self)
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The classic problem of finding the shortest path over a network has been the target of many research efforts over the years. These research efforts have resulted in a number of different algorithms and a considerable amount of empirical findings with respect to performance. Unfortunately, prior research does not provide a clear direction for choosing an algorithm when one faces the problem of computing shortest paths on real road networks. Most of the computational testing on shortest path algorithms has been based on randomly generated networks, which may not have the characteristics of real road networks. In this paper, we provide an objective evaluation of 15 shortest path algorithms using a variety of real road networks. Based on the evaluation, a set of recommended algorithms for computing shortest paths on real road networks is identified. This evaluation should be particularly useful to researchers and practitioners in operations research, management science, transportation, and Geographic Information Systems. The computation of shortest paths is an important task in many network and transportation related analyses. The development, computational testing, and efficient implementation of shortest path algorithms have remained important research topics within related disciplines such as operations
Redundant trees for preplanned recovery in arbitrary vertex—Redundant or edge redundant graphs
 IEEE/ACM Trans. Netw
, 1999
"... Abstract—We present a new algorithm which creates redundant trees on arbitrary noderedundant or linkredundant networks. These trees are such that any node is connected to the common root of the trees by at least one of the trees in case of node or link failure. Our scheme provides rapid preplanned ..."
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Cited by 62 (4 self)
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Abstract—We present a new algorithm which creates redundant trees on arbitrary noderedundant or linkredundant networks. These trees are such that any node is connected to the common root of the trees by at least one of the trees in case of node or link failure. Our scheme provides rapid preplanned recovery of communications with great flexibility in the topology design. Unlike previous algorithms, our algorithm can establish two redundant trees in the case of a node failing in the network. In the case of failure of a communications link, our algorithm provides a superset of the previously known trees. Index Terms—Graph theory, multicasting, network recovery, network robustness, routing, trees. I.
A Systematic Approach for Analyzing the Manufacturability of Machined Parts
, 1994
"... The ability to quickly introduce new quality products is a decisive factor in capturing market share. Because of pressing demands to reduce lead time, analyzing the manufacturability of the proposed design has become an important step in the design stage. This paper presents an approach for analy ..."
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Cited by 45 (20 self)
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The ability to quickly introduce new quality products is a decisive factor in capturing market share. Because of pressing demands to reduce lead time, analyzing the manufacturability of the proposed design has become an important step in the design stage. This paper presents an approach for analyzing the manufacturability of machined parts. Evaluating the manufacturability of a proposed design involves determining whether or not it is manufacturable with a given set of manufacturing operationsand if so, then finding the associated manufacturing efficiency. Since there can be several different ways to manufacture a proposed design, this requires us to consider different ways to manufacture it, in order to determine which one best meets the design and manufacturing objectives. The first step in our approach is to identify all machining operations which can potentially be used to create the given design. Using these operations, we generate different operation plans for machi...
Fast and Accurate Collision Detection for Haptic Interaction Using a Three DegreeofFreedom ForceFeedback Device
 In Proceedings of Virtual Reality Conference
"... We present a fast and accurate collision detection algorithm for haptic interaction with polygonal models. Given a model, we precompute a hybrid hierarchical representation, consisting of uniform grids (represented using a hash table) and trees of tightfitting oriented bounding box trees (OBBTrees ..."
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Cited by 44 (0 self)
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We present a fast and accurate collision detection algorithm for haptic interaction with polygonal models. Given a model, we precompute a hybrid hierarchical representation, consisting of uniform grids (represented using a hash table) and trees of tightfitting oriented bounding box trees (OBBTrees). At run time, we use hybrid hierarchical representations and exploit frametoframe coherence for fast proximity queries. We describe a new overlap test, which is specialized for intersection of a line segment with an oriented bounding box for haptic simulation and takes 4272 operations including transformation costs. The algorithms have been implemented as part of HCOLLIDE and interfaced with a PHANToM arm and its haptic toolkit, GHOST, and applied to a number of models. As compared to the commercial implementation, we are able to achieve up to 20 times speedup in our experiments and sustain update rates over 1000Hz on a 400MHz Pentium II. In practice, our prototype implementation can a...
Efficient event routing in contentbased publish/subscribe service network
 in Proc. of the 23 rd INFOCOM
, 2004
"... Abstract—Efficient event delivery in a contentbased publish/subscribe system has been a challenging problem. Existing group communication solutions, such as IP multicast or applicationlevel multicast techniques, are not readily applicable due to the highly heterogeneous communication pattern in su ..."
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Cited by 43 (1 self)
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Abstract—Efficient event delivery in a contentbased publish/subscribe system has been a challenging problem. Existing group communication solutions, such as IP multicast or applicationlevel multicast techniques, are not readily applicable due to the highly heterogeneous communication pattern in such systems. We first explore the design space of event routing strategies for contentbased publish/subscribe systems. Two major existing approaches are studied: filterbased approach, which performs contentbased filtering on intermediate routing servers to dynamically guide routing decisions, and multicastbased approach, which delivers events through a few highquality multicast groups that are preconstructed to approximately match user interests. These approaches have different tradeoffs in the routing quality achieved and the implementation cost and system load generated. We then present a new routing scheme called Kyra that carefully balance these tradeoffs. Kyra combines the advantages of contentbased filtering and eventspace partitioning in the existing approaches to achieve better overall routing efficiency. We use detailed simulations to evaluate Kyra and compare it with existing approaches. The results demonstrate the effectiveness of Kyra in achieving high network efficiency, reducing implementation cost and balancing system load across the publishsubscribe service network. Keywords—System design, simulations, publishsubscribe, event notification I.
Multirobot area patrol under frequency constraints
 Annals of Math and Artificial Intelligence
, 2009
"... Abstract — This paper discusses the problem of generating patrol paths for a team of mobile robots inside a designated target area. Patrolling requires an area to be visited repeatedly by the robot(s) in order to monitor its current state. First, we present frequency optimization criteria used for e ..."
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Cited by 41 (17 self)
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Abstract — This paper discusses the problem of generating patrol paths for a team of mobile robots inside a designated target area. Patrolling requires an area to be visited repeatedly by the robot(s) in order to monitor its current state. First, we present frequency optimization criteria used for evaluation of patrol algorithms. We then present a patrol algorithm that guarantees maximal uniform frequency, i.e., each point in the target area is covered at the same optimal frequency. This solution is based on finding a circular path that visits all points in the area, while taking into account terrain directionality and velocity constraints. Robots are positioned uniformly along this path, using a second algorithm. Moreover, the solution is guaranteed to be robust in the sense that uniform frequency of the patrol is achieved as long as at least one robot works properly. I.
A Fast Hierarchical Algorithm for 3D Capacitance Extraction
, 1998
"... We present a new algorithm for computing the capacitance of threedimensional perfect electrical conductors of complex structures. The new algorithm is significantly faster and uses much less memory than previous best algorithms, and is kernel independent. The new algorithm is based on a hierarchic ..."
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Cited by 35 (6 self)
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We present a new algorithm for computing the capacitance of threedimensional perfect electrical conductors of complex structures. The new algorithm is significantly faster and uses much less memory than previous best algorithms, and is kernel independent. The new algorithm is based on a hierarchical algorithm for the nbody problem, and is an acceleration of the boundaryelement method for solving the integral equation associated with the capacitance extraction problem. The algorithm first adaptively subdivides the conductor surfaces into panels according to an estimation of the potential coefficients and a usersupplied error bound. The algorithm stores the potential coefficient matrix in a hierarchical data structure of size O#n#, although the matrix is size n 2 if expanded explicitly, where n is the number of panels. The hierarchical data structure allows us to multiply the coefficient matrix with any vector in O#n# time. Finally, we use a generalized minimal residual algorithm to solve...