We revisit the computational complexity of decision problems about existence of Nash equilibria in multi-player games satisfying certain natural properties. Such problems have generally been shown to be complete for t...
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ISBN:
(纸本)9783031432538;9783031432545
We revisit the computational complexity of decision problems about existence of Nash equilibria in multi-player games satisfying certain natural properties. Such problems have generally been shown to be complete for the complexity class.R, that captures the complexity of the decision problem for the Existential Theory of the Reals. For most of these problems, we show that their complexity remains unchanged even when restricted to win-lose games, where all utilities are either 0 or 1.
Recent development of portable devices and prevalence of high-throughput communication infrastructures make the video encoding in portable devices on high demand. However, its computational complexity makes the implem...
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ISBN:
(纸本)9781424444632
Recent development of portable devices and prevalence of high-throughput communication infrastructures make the video encoding in portable devices on high demand. However, its computational complexity makes the implementation of real-time video encoder on portable devices extremely difficult. Many fast algorithms to solve the problems are not efficient from the view point of worst workload since they consider only reduction of average computational complexity. Moreover., since the amount of reduction of computational complexity highly depends on video sequence, fixed fast algorithms cannot always achieve their full potential for real-time encoding. In this paper, we analyze the complexity of H.264/AVC video coding tools, and develop two parameters for complexity control. Consequently, we design a power-aware complexity scalable encoding scheme implementable on embedded system. Using our target embedded system, the proposed method is verified to save power by about 50%.
This paper proposes a frequency averaging method to reduce computational complexity for the implementation of a two-channel parameterized multichannel Wiener filter (PMWF) algorithm. Experimental results show that the...
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ISBN:
(纸本)9781538630259
This paper proposes a frequency averaging method to reduce computational complexity for the implementation of a two-channel parameterized multichannel Wiener filter (PMWF) algorithm. Experimental results show that the proposed algorithm can reduce the amount of computation by 40.24 % compared to the conventional PMWF algorithm while preserving speech quality after the speech enhancement.
For a long time modeling approaches to stochastic programming were dominated by scenario generation methods. Consequently the main computational effort went into development of decomposition type algorithms for solvin...
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ISBN:
(纸本)9789814324342
For a long time modeling approaches to stochastic programming were dominated by scenario generation methods. Consequently the main computational effort went into development of decomposition type algorithms for solving constructed large scale (linear) optimization problems. A different point of view emerged recently where computational complexity of stochastic programming problems was investigated from the point of view of randomization methods based on Monte Carlo sampling techniques. In that approach the number of scenarios is irrelevant and can be infinite. On the other hand, from that point of view there is a principle difference between computational complexity of two and multistage stochastic programming problems - certain classes of two stage stochastic programming problems can be solved with a reasonable accuracy and reasonable computational effort, while (even linear) multistage stochastic programming problems seem to be computationally intractable in general.
We present in this paper how to assess the network routing logical security policy of an Internet Service Provider network, through a reverse-engineering process performed on the network routers configurations. This p...
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ISBN:
(纸本)0769518869
We present in this paper how to assess the network routing logical security policy of an Internet Service Provider network, through a reverse-engineering process performed on the network routers configurations. This paper covers the definition of a network routing logical security policy, how to implement it in the network routers configurations, in addition it details the algorithms and their asymptotic time complexity required to assess this security policy.
We show that the satisfiability problem in core fragments of modal logics T, K4, and S4 in whose languages diamond modal operators are disallowed is NL-complete. Moreover, we provide deterministic procedures for satis...
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ISBN:
(纸本)9783030195700;9783030195694
We show that the satisfiability problem in core fragments of modal logics T, K4, and S4 in whose languages diamond modal operators are disallowed is NL-complete. Moreover, we provide deterministic procedures for satisfiability checking. We show that the above fragments correspond to certain core fragments of linear temporal logic, hence our results imply NL-completeness of the latter.
In physics, systems having three parts are typically much more difficult to analyze than those having just two. Even in classical mechanics, predicting the motion of three interacting celestial bodies remains an insur...
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In physics, systems having three parts are typically much more difficult to analyze than those having just two. Even in classical mechanics, predicting the motion of three interacting celestial bodies remains an insurmountable challenge while the analogous two-body problem has an elementary solution. It is as if just by adding a third party, a fundamental change occurs in the structure of the problem that renders it unsolvable. In this thesis, we demonstrate how such an effect is likewise present in the theory of quantum entanglement. In fact, the complexity differences between two-party and three-party entanglement become quite conspicuous when comparing the difficulty in deciding what state changes are possible for these systems when no additional entanglement is consumed in the transformation process. We examine this entanglement transformation question and its variants in the language of computational complexity theory, a powerful subject that formalizes the concept of problem difficulty. Since deciding feasibility of a specified bipartite transformation is relatively easy, this task belongs to the complexity class P. On the other hand, for tripartite systems, we find the problem to be NP-Hard, meaning that its solution is at least as hard as the solution to some of the most difficult problems humans have encountered. One can then rigorously defend the assertion that a fundamental complexity difference exists between bipartite and tripartite entanglement since unlike the former, the full range of forms realizable by the latter is incalculable (assuming P≠NP). However, similar to the three-body celestial problem, when one examines a special subclass of the problem—invertible transformations on systems having at least one qubit subsystem—we prove that the problem can be solved efficiently. As a hybrid of the two questions, we find that the question of tripartite to bipartite transformations can be solved by an efficient randomized algorithm. Our results are obtain
In this dissertation, we study the dirty data evaluation and repairing problem in relational database. Dirty data is usually inconsistent, inaccurate, incomplete and stale. Existing methods and theories of consistency...
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In this dissertation, we study the dirty data evaluation and repairing problem in relational database. Dirty data is usually inconsistent, inaccurate, incomplete and stale. Existing methods and theories of consistency describe using integrity constraints, such as data dependencies. However, integrity constraints are good at detection but not at evaluating the degree of data inconsistency and cannot guide the data repairing. This dissertation first studies the computational complexity of and algorithms for the database inconsistency evaluation. We define and use the minimum tuple deletion to evaluate the database inconsistency. For such minimum tuple deletion problem, we study the relationship between the size of rule set and its computational complexity. We show that the minimum tuple deletion problem is NP-hard to approximate the minimum tuple deletion within 17/16 if given three functional dependencies and four attributes involved. A near optimal approximated algorithm for computing the minimum tuple deletion is proposed with a ratio of 2 − 1/2r , where r is the number of given functional dependencies. To guide the data repairing, this dissertation also investigates the data repairing method by using query feedbacks, formally studies two decision problems, functional dependency restricted deletion and insertion propagation problem, corresponding to the feedbacks of deletion and insertion. A comprehensive analysis on both combined and data complexity of the cases is provided by considering different relational operators and feedback types. We have identified the intractable and tractable cases to picture the complexity hierarchy of these problems, and provided the efficient algorithm on these tractable cases. Two improvements are proposed, one focuses on figuring out the minimum vertex cover in conflict graph to improve the upper bound of tuple deletion problem, and the other one is a better dichotomy for deletion and insertion propagation problems at the absence o
We are interested in computation of arbitrage condition in financial market with friction. We consider a deterministic model with a finite number of financial assets and a finite number of possible states of nature. T...
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In this paper we study a set of problems that are of considerable importance to Statistical Machine Translation (SMT) but which have not been addressed satisfactorily by the SMT research community. Over the last decad...
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ISBN:
(纸本)1932432590
In this paper we study a set of problems that are of considerable importance to Statistical Machine Translation (SMT) but which have not been addressed satisfactorily by the SMT research community. Over the last decade, a variety of SMT algorithms have been built and empirically tested whereas little is known about the computational complexity of some of the fundamental problems of SMT. Our work aims at providing useful insights into the the computational complexity of those problems. We prove that while IBM Models 1-2 are conceptually and computationally simple, computations involving the higher (and more useful) models are hard. Since it is unlikely that there exists a polynomial time solution for any of these hard problems (unless P = NP and P#P = P), our results highlight and justify the need for developing polynomial time approximations for these computations. We also discuss some practical ways of dealing with complexity.
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