共查询到20条相似文献，搜索用时 203 毫秒
1.
This paper deals with the problem of finding graphs (directed and undirected) maximizing the number of spanning trees among the regular graphs with the same number of nodes and edges. The approach is based on heuristic algorithms such as k-optimal and evolutionary. The emphasis is rather on checking whether these techniques are applicable to solving extremal graph problems than investigating generic structures of optimal graphs. For this reason circulant graphs, for which computationally effective tree counting formulas exist, are discussed first and then the results extended to cover the class of regular graphs. 相似文献
2.
委托代理树:一种产业组织优化方法 总被引：1，自引：0，他引：1
本文将组织内部的各种关系模拟成委托代理关系,在引入“树”的概念基础上,将组织内部的产业组织看成一棵委托代理树,并用简单明了的方法将委托代理树的大小用数字刻画出来,然后对委托代理树进行修枝,使树尽可能小,以达到节省组织成本(内部交易成本)、优化组织结构的目的。 相似文献
3.
4.
引入矢量量化器码书的特征变量，提出基于结构化码书的两级波形矢量量化器设计新算法。算法包括：合理构造初始码书、快速训练码书、快速量化输入矢量。通过计算机对语音信号矢量量化的模拟，结果表明新算法明显地缩短了复杂度和提高了矢量量化的速度。 相似文献
5.
6.
In this paper, we consider the distributed optimization problems with linear coupling constraint of general homogeneous and heterogeneous linear multi-agent systems under weighted-balanced and strongly connected digraphs. In order to control all agents converge to the optimal output, we propose distributed control laws, therein, the optimal output can make the global cost function reach minimum. Then we guarantee the convergence of the proposed algorithms by the properties of Laplacian matrix and Lyapunov stability theorem. Furthermore, we extend the result of heterogeneous linear multi-agent system to the case that dynamics of agents are subject to external disturbances, and prove that the algorithm designed by internal model principle can make all agents reach the optimal output exactly. Finally, we provide examples to illustrate the effectiveness of the proposed distributed algorithms. 相似文献
7.
8.
9.
A self-organization algorithm for image compression and the associated VLSI architecture are presented. A frequency upper-threshold is effectively used in the centroid learning method. Performances of the self-organization networks and traditional nonself-organization algorithms for vector quantization are compared. This new algorithm is quite efficient and can achieve near-optimal results. A trainable VLSI neuroprocessor based upon this new self-organization network has been developed for high-speed and high-ratio image compression applications. This neural-based vector quantization design includes a fully parallel vector quantizer and a pipelined codebook generator which obtains a time complexity O (1) for each quantization vector. A 5 × 5-dimensional vector quantizer prototype chip has been designed and fabricated. It contains 64 inner-product neural units and an extendable winner-take-all block. This mixed-signal chip occupies a compact silicon area of 4.6 × 6.8 mm2 in a 2.0-μm scalable CMOS technology. It provides a computing capability as high as 3.33 billion connections per second. It can achieve a speedup factor of 110 compared with a SUN-4/75 workstation for a compression ratio of 33. Real-time adaptive VQ on industrial 1024 × 1024 pixel images is feasible using multiple neuroprocessor chips. An industrial-level design to achieve 104 billion connections per second for the 1024-codevector vector quantizer can be fabricated in a 125 mm2 chip through a 1 μm CMOS technology. 相似文献
10.
中值淘汰法的主要目的是为了打破现代分支系统学中采用最简原理所带来的不确定性僵局。然而，在两个或两个以上分类单元都具有相同衍进指数的情况下，该方法也能不止产生一个分支系统树，因为没有一个客观标准来确定应该先连接哪一个分类单元，而连接的先后顺序不同，就会产生不同的分支系统树。中值淘汰法的作者认为，该法产生的结果不用简约性来判定。但是，该法也能构成最简约的分支系统树。本文还对应用中值淘汰法所面临的问题作了讨论。 相似文献
11.
Chandrawati Kumari Bijo Varughese Siddarth Ramji Seema Kapoor 《Indian journal of clinical biochemistry : IJCB》2016,31(4):414-422
Pre analytical process of extraction for accurate detection of organic acids is a crucial step in diagnosis of organic acidemias by GCMS analysis. This process is accomplished either by solid phase extraction (SPE) or by liquid–liquid extraction (LLE). Both extraction procedures are used in different metabolic laboratories all over the world. In this study we compared these two extraction procedures in respect of precision, accuracy, percent recovery of metabolites, number of metabolites isolated, time and cost in a resource constraint setup. We observed that the mean recovery from SPE was 84.1 % and by LLE it was 77.4 % (p value <0.05). Moreover, the average number of metabolites isolated by SPE and LLE was 161.8 ± 18.6 and 140.1 ± 20.4 respectively. The processing cost of LLE was economical. In a cost constraint setting using LLE may be the practical option if used for organic acid analysis. 相似文献
12.
In this paper, we address the problem of relation extraction of multiple arguments where the relation of entities is framed by multiple attributes. Such complex relations are successfully extracted using a syntactic tree-based pattern matching method. While induced subtree patterns are typically used to model the relations of multiple entities, we argue that hard pattern matching between a pattern database and instance trees cannot allow us to examine similar tree structures. Thus, we explore a tree alignment-based soft pattern matching approach to improve the coverage of induced patterns. Our pattern learning algorithm iteratively searches the most influential dependency tree patterns as well as a control parameter for each pattern. The resulting method outperforms two baselines, a pairwise approach with the tree-kernel support vector machine and a hard pattern matching method, on two standard datasets for a complex relation extraction task. 相似文献
13.
Christopher J. Damaren 《Journal of The Franklin Institute》2006,343(3):271-278
In this paper, we consider the H2-optimal control problem subject to the constraint that the resulting controller be strictly positive real. A direct numerical optimization approach is adopted in conjunction with a controller parametrization that is linear in the unknown parameters. The SPR constraint is easily expressed at each frequency in the form of a linear inequality. The method is applied to a numerical example from the literature and good results are achieved. In particular, the proposed method is particularly adept at determining low order controllers. 相似文献
14.
Camilla B. Schwind 《Information processing & management》1983,19(4):223-235
This paper presents a formalism for the representation of complex semantic relations among concepts of natural language. We define a semantic algebra as a set of atomic concepts together with an ordered set of semantic relations. Semantic trees are a graphical representation of a semantic algebra (comparable to Kantorovic trees for boolean or arithmetical expressions). A semantic tree is an ordered tree with nodes labeled with relation and concept names. We generate semantic trees from natural language texts in such a way that they represent the semantic relations which hold among the concepts occurring within that text. This generation process is carried out by a transformational grammar which transforms directly natural language sentences into semantic trees. We present an example for concepts and relations within the domain of computer science where we have generated semantic trees from definition texts by means of a metalanguage for transformational grammars (a sort of metacompiler for transformational grammars). The semantic trees generated so far serve for thesaurus entries in an information retrieval system. 相似文献
15.
The problem considered here is the optimal scheduling of a Boolean expression on a single-processor system. We consider a Boolean expression in which each Boolean variable represents the binary outcome (or return code) of a program module. The result of the expression may be known without executing all modules (e.g. an OR-operation is terminated as soon as one of the operands returns the value 1), so that the order in which the modules are executed influences the cost involved in finding the result. The optimisation discussed here consists in finding the operand arrangement that minimizes the average execution cost. The cost of each module represents the consumption of resources such as CPU time, elapsed time, number of input-outputs, etc. The assumptions regarding the modules are: (i) No module execution is the pre-requisite for the execution of another module. (ii) At each execution, the return code and the cost of a module do not depend on the sequence of execution. (iii) Over a number of executions, the return code and the cost of a module may be statistically dependent or a deterministic function of return codes and costs of other modules.A prototype scheduler is presented, that implements a sub-optimal strategy. It stores the Boolean expression in tabular form, passes control to a module at a time, as needed for the Boolean computation, measures the cost of execution and decides empirically what operand arrangement is more advantageous. 相似文献
16.
The usual use of fractals involves self-similar geometrical objects to fill a space, where the self-similar iterations may continue ad infinitum. This is the first paper to propose the use of self-similar mechanical objects that fill an alloted space, while achieving an invariance property as the self-similar iterations continue (e.g. invariant strength). Moreover, for compressive loads, this paper shows how to achieve minimal mass and invariant strength from self-similar structures. The topology optimization procedure uses self-similar iteration until minimal mass is achieved, and this problem is completely solved, with global optimal solutions given in closed form. The optimal topology remains independent of the magnitude of the load. Mass is minimized subject to yield and/or buckling constraints. Formulas are also given to optimize the complexity of the structure, and the optimal complexity turns out to be finite. That is, a continuum is never the optimal structural for a compressive load under any constraints on the physical dimension (diameter). After each additional self-similar iteration, the number of bars and strings increase, but, for a certain choice of unit topology shown, the total mass of bars and strings decreases. For certain structures, the string mass monotonically increases with iteration, while the bar mass monotonically reduces, leading to minimal total mass in a finite number of iterations, and hence a finite optimal complexity for the structure. The number of iterations required to achieve minimal mass is given explicitly in closed form by a formula relating the chosen unit geometry and the material properties. It runs out that the optimal structures produced by our theory fall in the category of structures we call tensegrity. Hence our self-similar algorithms can generate tensegrity fractals. 相似文献
17.
《Journal of The Franklin Institute》2023,360(4):2955-2975
This paper focuses on binary optimal control of fed-batch fermentation of glycerol by Klebsiella pneumoniaewith pH feedback considering limited number of switches. To maximize the concentration of 1,3-propanediol at terminal time, we propose a binary optimal control problem subjected to time-coupled combinatorial constraint with the ratio of feeding rate of glycerol to that of NaOH as control variables. Based on time-scaling transformation and discretization, the binary optimal control problem is first transformed into a mixed binary parameter optimization problem consisting of not only continuous variables but also binary variables, which is then divided into two subproblems via combinatorial integral approximation decomposition. Finally, a novel fruit fly optimizer with modified sine cosine algorithm and adaptive maximum dwell rounding are applied to solve the obtained subproblems numerically. Numerical results show the rationality and feasibility of the proposed method. 相似文献
18.
The problem is to determine the linear graph that has the maximum number of spanning trees, where only the number of nodes N and the number of branches B are prescribed. We deal with connected graphs G(N,B) obtained by deleting D branches from a complete graph KN. Our solution is for D less than or equal to N 相似文献
19.
《Journal of The Franklin Institute》2006,343(4-5):501-520
Protocol synthesis is used to derive a protocol specification, that is, the specification of a set of application components running in a distributed system of networked computers, from a specification of services (called the service specification) to be provided by the distributed application to its users. Protocol synthesis reduces design costs and errors by specifying the message exchanges between the application components, as defined by the protocol specifications. In this paper, we propose a new synthesis method that generates optimized protocol specification. Both service and protocol specifications are described using extended Petri nets. Particularly, we propose an integer linear programming model that derives distributed applications with minimum communication costs. The model determines an optimal allocation of resources that minimizes communication costs. Our model can treat several reasonable cost criteria that could be used in various related application areas. Particularly, we have considered the following cost criteria: (a) the number of messages exchanged between different distributed applications, (b) the size of messages, (c) the number of messages based on frequency of execution, (d) communication channel costs, and (e) resource placement costs. An application example is given along with some experimental results. 相似文献
20.
电信产业管制分析:基于管制激励理论的视角 总被引：2，自引：0，他引：2
本文利用管制激励理论的最新成果,建立了一个电信产业管制模型,并通过放松电信管制机构的激励相容约束条件,分析在此约束条件不能保证的情况下立法者的最优管制政策.研究结果表明:(1)立法者采取的最优管制政策由两种相反方向的力量决定:一是电信管制机构能被激励相容的概率的大小,二是电信运营商贿赂的成本的大小.(2)提高电信运营商行贿成本和管制机构的风险偏好,可以使被管制企业如实地显示出其成本信息. 相似文献