We present a data model for movies and movie databases. A movie is considered to be a 2D semi-algebraic figure that can change in time. We give a number of computability results concerning movies: it can be decided wh...
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We present a data model for movies and movie databases. A movie is considered to be a 2D semi-algebraic figure that can change in time. We give a number of computability results concerning movies: it can be decided whether a frame of a movie is only a topologically transformation of another frame; a movie has a finite number of scenes and cuts and these can be effectively computed. Based on these computability results we define an SQL-like query language for movie databases. This query language supports most movie editing operations like cutting, pasting and selection of scenes.
We describe a distributed computing primitive termed polling that is both a means of synchronization and communication in distributed or concurrent systems. The polling operation involves the collection of messages fr...
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We describe a distributed computing primitive termed polling that is both a means of synchronization and communication in distributed or concurrent systems. The polling operation involves the collection of messages from nodes in an interconnection network, in response to a query. We define the semantics of polling, and present algorithms for implementing the operation on complete and hypercube networks. Time and message lower bounds are presented, and are followed by an analysis of the number of operations performed at each node for every algorithm. We show that polling in a complete graph on 2n vertices can be completed in 2n rounds using 2n+2n-3+[2n-3+1/3]-1 messages. In case of n-cube, we show that polling in 2n rounds requires [2n+1/32n-1+1/6√2n-4/3] messages and we present an algorithm that completes polling in 2n rounds and sends 2n+3·2n-4-1 messages.
It is well known that for the case of a countable partial order, the ideal completion and the chain completion coincide. We investigate the boundary at which the chain and ideal completion do not coincide. We show in ...
It is well known that for the case of a countable partial order, the ideal completion and the chain completion coincide. We investigate the boundary at which the chain and ideal completion do not coincide. We show in particular that the ideal completion is not sequentially adequate; that is it is not possible in general to simply replace the ideal completion with a completion based on sequences as for instance the chain completion. The implications of this result for the Yoneda completion ([1]) and for the Smyth completion ([7,8,9,10,11]) which are based on the ideal completion, are discussed in an extended version of this paper, reported in [5].
We consider load balancing in the following setting. The on-line algorithm is allowed to use n machines, whereas the optimal off-line algorithm is limited to m machines, for some fixed m less than or equal n. We show ...
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The concept of multicovering radius was introduced by A. Klapper (see IEEE Trans. Inform. Theory, vol.43, p.1372-7, 1997) in the context of studying the security of stream ciphers. The purpose of this paper is to deri...
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The concept of multicovering radius was introduced by A. Klapper (see IEEE Trans. Inform. Theory, vol.43, p.1372-7, 1997) in the context of studying the security of stream ciphers. The purpose of this paper is to derive new bounds by relating the multicovering radii of a code to a relative notion of covering radius. For generality, we define this notion for multicovering radii, although we only use the ordinary covering radius version.
A simple approach is developed to use semantics as defined by virtual actions to guide the construction of manipulable symbol representations for objects and actions, in particular to obtain a model of syntactic proce...
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A simple approach is developed to use semantics as defined by virtual actions to guide the construction of manipulable symbol representations for objects and actions, in particular to obtain a model of syntactic processing in the developing infant. This uses a simplified model of the frontal lobes, and in particular the various sets of neurons involved in the process of chunking of temporal sequences observed in monkeys. The manner in which such neurons play a role in phrase structure grammar is elucidated at a simple level.
An FPGA switch box is said to be hyper-universal if it is routable for all possible surrounding multi-pin net topologies satisfying the routing resource constraints. It is desirable to design hyper-universal switch bo...
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ISBN:
(纸本)0780364457
An FPGA switch box is said to be hyper-universal if it is routable for all possible surrounding multi-pin net topologies satisfying the routing resource constraints. It is desirable to design hyper-universal switch boxes with the minimum number of switches. A previous work, Universal Switch Module, considered such a design problem concerning 2-pin net routings around a single FPGA switch box. However, as most nets are multi-pin nets in practice, it is imperative to study the problem that involves multi-pin nets. In this paper, we provide a new view of global routings and formulate the most general k-sided switch box design problem into an optimum k-partite graph design problem. Applying a powerful decomposition theorem of global routings, we prove that, for a fixed k, the number of switches in an optimum k-sided switch box with W terminals on each side is O (W), by constructing some hyper-universal switch boxes with O(W) switches. Furthermore, we obtain optimum, hyper-universal 2-sided and 3-sided switch boxes, and propose hyper-universal 4-sided switch boxes with less than 6.7 W switches, which is very close to the lower bound 6 W obtained for pure 2-pin net models.
Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600 [less-than or equal to...
Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600 [less-than or equal to] Re [less-than or equal to] 1800. The computational domain has seven contiguous transverse grooves cut symmetrically into opposite walls, followed by a flat section with the same length. Periodic inflow/outflow boundary conditions are employed. The development and decay of unsteady flow is observed in the grooved and flat sections, respectively. The axial variation of the unsteady component of velocity is compared to the local heat transfer, shear stress and pressure gradient. The results suggest that intermittently grooved passages may offer even higher heat transfer for a given pumping power than the levels observed in fully grooved passages.
Computational complexity of algorithms for solving problems has been at the heart of theoretical computerscience. Traditionally, the computational cost of an algorithm is estimated by "counting" operations ...
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Computational complexity of algorithms for solving problems has been at the heart of theoretical computerscience. Traditionally, the computational cost of an algorithm is estimated by "counting" operations combinatorially depending on the algorithm. We present a very different method for estimating cost of solving problem, incorporating ideas from information theory. Algorithms can be viewed as "search" procedures on the input (output) space. This naturally makes computational cost of algorithm as function of "entropy" of input (output) distribution. The relation of computational complexity and "entropy" of distribution depends on the particular "operations" used by algorithm to solve problem. This particular mapping between computational scale and "entropy" scale is independent of problem. We demonstrate the use of this method in classical "searching" and "sorting" problems. We work out many different searching and sorting algorithms' complexity using this method. In process, we also come up with new algorithms to solve some cases of searching and sorting that are aware of input distribution.
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