Replacement Rules Research Articles

Quark fragmentation within an identified jet

We derive a factorization theorem that describes an energetic hadron $h$ fragmenting from a jet produced by a parton $i$, where the jet invariant mass is measured. The analysis yields a ``fragmenting jet function'' ${\mathcal{G}}_{i}^{h}(s,z)$ that depends on the jet invariant mass $s$, and on the energy fraction $z$ of the fragmentation hadron. We show that ${\mathcal{G}}_{i}^{h}$ can be computed in terms of perturbatively calculable coefficients, ${\mathcal{J}}_{ij}(s,z/x)$, integrated against standard nonperturbative fragmentation functions, ${D}_{j}^{h}(x)$. We also show that $\ensuremath{\sum}_{h}\ensuremath{\int}dz{\mathcal{G}}_{i}^{h}(s,z)$ is given by the standard inclusive jet function ${J}_{i}(s)$ which is perturbatively calculable in QCD. We use soft collinear effective theory and for simplicity carry out our derivation for a process with a single jet, $\overline{B}\ensuremath{\rightarrow}Xh\ensuremath{\ell}\overline{\ensuremath{\nu}}$, with invariant mass ${m}_{Xh}^{2}\ensuremath{\gg}{\ensuremath{\Lambda}}_{\mathrm{QCD}}^{2}$. Our analysis yields a simple replacement rule that allows any factorization theorem depending on an inclusive jet function ${J}_{i}$ to be converted to a semi-inclusive process with a fragmenting hadron $h$. We apply this rule to derive factorization theorems for $\overline{B}\ensuremath{\rightarrow}XK\ensuremath{\gamma}$ which is the fragmentation to a Kaon in $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$, and for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}(\mathrm{\text{dijets}})+h$ with measured hemisphere dijet invariant masses.

Distinguishing the opponents promotes cooperation in well-mixed populations

Cooperation has been widely studied when an individual strategy is adopted against all coplayers. In this context, some extra mechanisms, such as punishment, reward, memory, and network reciprocity must be introduced in order to keep cooperators alive. Here, we adopt a different point of view. We study the adoption of different strategies against different opponents instead of adoption of the same strategy against all of them. In the context of the prisoner dilemma, we consider an evolutionary process in which strategies that provide more benefits are imitated and the players replace the strategy used in one of the interactions furnishing the worst payoff. Individuals are set in a well-mixed population, so that network reciprocity effect is excluded and both synchronous and asynchronous updates are analyzed. As a consequence of the replacement rule, we show that mutual cooperation is never destroyed and the initial fraction of mutual cooperation is a lower bound for the level of cooperation. We show by simulation and mean-field analysis that (i) cooperation dominates for synchronous update and (ii) only the initial mutual cooperation is maintained for asynchronous update. As a side effect of the replacement rule, an "implicit punishment" mechanism comes up in a way that exploitations are always neutralized providing evolutionary stability for cooperation.

After Alice: Alice and the Dry Tail

According to Gilles Deleuze, the underground world of Alice in Wonderland has been strongly associated with animality and embodiment. Thus the need for Alice's eventual climb to the surface and her discovery that everything linguistic happens at that border. Yet, strangely, in spite of the claim that Alice disavows false depth and returns to the surface, it seems that it is precisely in the depths that she finally wakes from her sleepy, stupified surface state and investigates the deep structures, the rules of logic. In this investigation, Alice questions many formal structures, such as causality, identity, reference and the rules of replacement. She discovers that Wonderland does not generate consequential conduct; in fact, it generates no conduct whatsoever! In other words, when it comes to consequences, Wonderland may not be all that wonderful. Yet, we do not live in Wonderland and therefore, our actions have consequences. The question this poses is, why organise language so as to escape causal relations and why choose the little girl as emblematic of this organisation?

A PRIMER ON SUMMARIZING MOLT DATA FOR FLIGHT FEATHERS

Abstract Once established with reliability, the rules of flight feather replacement become an important component of comparative life-history studies. Here I illustrate the form of tables that should be used to describe the pattern and intensity of flight feather molt. Using a subset of original data summarizing primary, secondary, and rectrix molt in Western Kingbirds (Tyrannus verticalis), I show how to assign scores indicating direction of replacement and points where waves of molt started or will stop. Combining these scores across birds yields a molt summary table, the starting point for determining the rules of feather replacement. This raw summary table is then iterated to show breaks between molt series and how summary scores around these breaks are reassigned to acknowledge series breaks. Molt summary tables also give sample sizes, because the rules of flight feather replacement cannot reliably be inferred unless birds in active molt are available for all the feathers being considered.

Improving the Computational Efficiency of Thermodynamical Genetic Algorithms

PDF HTML阅读 XML下载 导出引用 引用提醒 热力学遗传算法计算效率的改进 DOI: 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: Supported by the National Natural Science Foundation of China under Grant Nos.60473014, 60773009 (国家自然科学基金); the National High-Tech Research and Development Plan of China under Grant No.2007AA01Z290 (国家高技术研究发展计划(863)); the China Scholarship Council under Grant No.2007101731 (国家留学基金); the Natural Science Foundation of Hubei Province of China under Grant No.2007ABA009 (湖北省自然科学基金) Improving the Computational Efficiency of Thermodynamical Genetic Algorithms Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:热力学遗传算法(thermodynamical genetic algorithms,简称TDGA)借鉴固体退火过程中能量与熵的竞争模式来协调GA中"选择压力"和"种群多样性"之间的冲突.然而TDGA目前极高的计算代价限制了其应用.为了提高TDGA的计算效率,首先定义一种等级熵(rating-based entropy,简称RE)度量方法,它能以较小的计算成本度量种群中个体适应值的分散程度.然后引入分量热力学替换规则(component thermodynamical replacement,简称CTR),有效地降低了替换规则的复杂度.同时也证明了CTR规则具有驱动种群自由能近似最速下降的能力.在0-1背包问题上的实验结果表明,RE方法和CTR规则在保持TDGA良好的性能与稳定性的同时,极大地提高了其计算效率. Abstract:Thermodynamical genetic algorithms (TDGA) simulate the competitive model between energy and entropy in annealing to harmonize the conflicts between selective pressure and population diversity in GA. But high computational cost restricts the applications of TDGA. In order to improve the computational efficiency, a measurement method of rating-based entropy (RE) is proposed. The RE method can measure the fitness dispersal with low computational cost. Then a component thermodynamical replacement (CTR) rule is introduced to reduce the complexity of the replacement, and it is proved that the CTR rule has the approximate steepest descent ability of the population free energy. Experimental results on 0-1 knapsack problems show that the RE method and the CTR rule not only maintain the excellent performance and stability of TDGA, but also remarkably improve the computational efficiency of TDGA. 参考文献 相似文献 引证文献

The Crowding Approach to Niching in Genetic Algorithms

A wide range of niching techniques have been investigated in evolutionary and genetic algorithms. In this article, we focus on niching using crowding techniques in the context of what we call local tournament algorithms. In addition to deterministic and probabilistic crowding, the family of local tournament algorithms includes the Metropolis algorithm, simulated annealing, restricted tournament selection, and parallel recombinative simulated annealing. We describe an algorithmic and analytical framework which is applicable to a wide range of crowding algorithms. As an example of utilizing this framework, we present and analyze the probabilistic crowding niching algorithm. Like the closely related deterministic crowding approach, probabilistic crowding is fast, simple, and requires no parameters beyond those of classical genetic algorithms. In probabilistic crowding, subpopulations are maintained reliably, and we show that it is possible to analyze and predict how this maintenance takes place. We also provide novel results for deterministic crowding, show how different crowding replacement rules can be combined in portfolios, and discuss population sizing. Our analysis is backed up by experiments that further increase the understanding of probabilistic crowding.

Totally correct logic program transformations via well-founded annotations

We address the problem of proving the total correctness of transformations of definite logic programs. We consider a general transformation rule, called clause replacement, which consists in transforming a program P into a new program Q by replacing a set Γ 1 of clauses occurring in P by a new set Γ 2 of clauses, provided that Γ 1 and Γ 2 are equivalent in the least Herbrand model M(P) of the program P. We propose a general method for proving that transformations based on clause replacement are totally correct, that is, M(P)=M(Q). Our method consists in showing that the transformation of P into Q can be performed by: (i) adding extra arguments to predicates, thereby deriving from the given program P an annotated program $\overline{P}$ , (ii) applying a variant of the clause replacement rule and transforming the annotated program $\overline{P}$ into a terminating annotated program $\overline{Q}$ , and (iii) erasing the annotations from $\overline{Q}$ , thereby getting Q. Our method does not require that either P or Q are terminating and it is parametric with respect to the annotations. By providing different annotations we can easily prove the total correctness of program transformations based on various versions of the popular unfolding, folding, and goal replacement rules, which can all be viewed as particular cases of our clause replacement rule.

The persistent‐access‐caching algorithm

AbstractCaching is widely recognized as an effective mechanism for improving the performance of the World Wide Web. One of the key components in engineering the Web caching systems is designing document placement/replacement algorithms for updating the collection of cached documents. The main design objectives of such a policy are the high cache hit ratio, ease of implementation, low complexity and adaptability to the fluctuations in access patterns. These objectives are essentially satisfied by the widely used heuristic called the least‐recently‐used (LRU) cache replacement rule. However, in the context of the independent reference model, the LRU policy can significantly underperform the optimal least‐frequently‐used (LFU) algorithm that, on the other hand, has higher implementation complexity and lower adaptability to changes in access frequencies. To alleviate this problem, we introduce a new LRU‐based rule, termed the persistent‐access‐caching (PAC), which essentially preserves all of the desirable attributes of the LRU scheme. For this new heuristic, under the independent reference model and generalized Zipf's law request probabilities, we prove that, for large cache sizes, its performance is arbitrarily close to the optimal LFU algorithm. Furthermore, this near‐optimality of the PAC algorithm is achieved at the expense of a negligible additional complexity for large cache sizes when compared to the ordinary LRU policy, since the PAC algorithm makes the replacement decisions based on the references collected during the preceding interval of fixed length. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008

Totally correct logic program transformations via well-founded annotations

We address the problem of proving the total correctness of transformations of definite logic programs. We consider a general transformation rule, called clause replacement, which consists in transforming a program P into a new program Q by replacing a set Γ 1 of clauses occurring in P by a new set Γ 2 of clauses, provided that Γ 1 and Γ 2 are equivalent in the least Herbrand model M(P) of the program P.We propose a general method for proving that transformations based on clause replacement are totally correct, that is, M(P)=M(Q). Our method consists in showing that the transformation of P into Q can be performed by: (i) adding extra arguments to predicates, thereby deriving from the given program P an annotated program \(\overline{P}\) , (ii) applying a variant of the clause replacement rule and transforming the annotated program \(\overline{P}\) into a terminating annotated program \(\overline{Q}\) , and (iii) erasing the annotations from \(\overline{Q}\) , thereby getting Q.Our method does not require that either P or Q are terminating and it is parametric with respect to the annotations. By providing different annotations we can easily prove the total correctness of program transformations based on various versions of the popular unfolding, folding, and goal replacement rules, which can all be viewed as particular cases of our clause replacement rule.

Powerful Features of the Modern Syllogistic Method of Propositional Logic

In traditional propositional logic, many replacement and inference rules were involved to ascertain if the truth of several antecedents implied the truth of a particular consequent. This research described a powerful technique called the Modern Syllogistic Method (MSM), which ferreted out from a set of premises all that can be concluded from it and casted the resulting conclusions in the simplest and most compact form. We observed that all replacement rules were explicitly and inherently integrated within the MSM and proved that all inference rules were simply limited special cases of it. This meant that the MSM constituted a complete method of logic deduction. We also showed how to use the MSM in determining whether inconsistencies existed within a given set of premises and also in detecting formal logical fallacies. We demonstrated the applicability of the method in diverse fields via four examples that illustrated its mathematical details and exhibited the nature of conclusions it can come up with. In fact, these examples demonstrated the possibility of extracting deductions that were not so obvious and even surprising. The examples also showed how logic can be misused and how logic misuse can be avoided or detected.

Spatial Layout Planning in Sub-Surface Rail Station Design for Effective Fire Evacuation

Spatial layout planning is an important part of the underground railway station design process, taking into account its need-driven nature and the resulting infrastructure that is sized on demand. The predicted passenger flow rates are the underlining factor and are divided into ‘levels of service’ for space planning considerations. This paper reports on the development of a knowledge-based computer design environment capable of generating multiple spatial layout solutions, thus providing for more effective fire evacuation analysis when compared with the traditional design process. The developed programme, titled SGEvac in this research, utilizes shape grammar theory to provide for automatic generation of solutions at the reference (preliminary) design level, based on visual rules of shape recognition and replacement, their connectivity and spatial relationships. Although it has been developed to meet London Underground Station Planning Standards and Guidelines (SPSG) and related codes of practice, it has both the scope and potential for redevelopment to any other country's design legislation. Novel shape grammar and functional logic design rules that incorporate station planning design knowledge and guidance are developed and specified, along with the theoretical research. Validation of the results thus far is discussed, with a ‘train on fire in a station’ evacuation scenario analysed.

Generalized Pólya urn Designs with Null Balance

In this paper we propose a class of sequential urn designs based on generalized Pólya urn (GPU) models for balancing the allocations of two treatments in sequential clinical trials. In particular, we consider a GPU model characterized by a 2 x 2 random addition matrix with null balance (i.e. null row sums) and replacement rule depending upon the urn composition. Under this scheme, the urn process has a Markovian structure and can be regarded as a random extension of the classical Ehrenfest model. We establish almost sure convergence and asymptotic normality for the frequency of treatment allocations and show that in some peculiar cases the asymptotic variance of the design admits a natural representation based on the set of orthogonal polynomials associated with the corresponding Markov process.

Generalized Pólya urn Designs with Null Balance

In this paper we propose a class of sequential urn designs based on generalized Pólya urn (GPU) models for balancing the allocations of two treatments in sequential clinical trials. In particular, we consider a GPU model characterized by a 2 x 2 random addition matrix with null balance (i.e. null row sums) and replacement rule depending upon the urn composition. Under this scheme, the urn process has a Markovian structure and can be regarded as a random extension of the classical Ehrenfest model. We establish almost sure convergence and asymptotic normality for the frequency of treatment allocations and show that in some peculiar cases the asymptotic variance of the design admits a natural representation based on the set of orthogonal polynomials associated with the corresponding Markov process.

Limits of Vertex Replacement Rules

Limits of Vertex Replacement Rules

The dimensions of limits of vertex replacement rules

Given an initial graph $G$, one may apply a rule $\R$ to $G$ which replaces certain vertices of $G$ with other graphs called replacement graphs to obtain a new graph $\R(G)$. By iterating this procedure on each resulting graph, a sequence of graphs $\{\R^n(G)\}$ is obtained. When the graphs in this sequence are normalized to have diameter one, questions of convergence can be investigated. Sufficient conditions for convergence in the Gromov-Hausdorff metric were given by J. Previte, M. Previte, and M. Vanderschoot for such normalized sequences of graphs when the replacement rule $\R$ has more than one replacement graph. M. Previte and H.S. Yang showed that under these conditions, the limits of such sequences have topological dimension one. In this paper, we compute the box and Hausdorff dimensions of limit spaces of normalized sequences of iterated vertex replacements when there is more than one replacement graph. Since the limit spaces have topological dimension one and typically have Hausdorff (and box) dimension greater than one, they are fractals. Finally, we give examples of vertex replacement rules that yield fractals.

Optimisation of the decision tree technique applied to simulated sow herd datasets

In this study, the robustness of the C4.5-decision tree algorithm was applied to sow herd datasets for investigating the limitations of this analysing technique. First, simulated sow herd datasets including inconsistent farmer culling policies which appear in real datasets were classified. These results were compared with very uniform and simple replacement rules. Furthermore, an optimisation of different pruning methods which can be changed in the decision tree tool was done. The evaluation parameters of all classifications were calculated with the stratified fold cross-validation and varying the number of folds showed that 10 folds were an appropriate number of subdividing the datasets. By simplifying the sow selection in the simulation, the sensitivity and error rate of the datasets showed improved values. In particular, datasets with randomly selected and inconsistent culling rules showed less sensitivities between 20 and 53%. A comparison of the classification of datasets with pruning or without pruning showed that with pruning, smaller sizes of trees resulted. The pruning class had a decrease of 23 leaves and 46 nodes, as compared to the without-pruning class, in the highest branching example. Differences exist between the two different pruning methods in the classification parameters and also in the tree size in dependence of the sow herd performance level and the size of the datasets.

The topological dimension of limits of vertex replacements

Given an initial graph G, one may apply a rule R to G which replaces certain vertices of G with other graphs called replacement graphs to obtain a new graph R ( G ) . By iterating this procedure, a sequence of graphs { R n ( G ) } is obtained. When each graph in this sequence is normalized to have diameter one, the resulting sequence may converge in the Gromov–Hausdorff metric. In this paper, we compute the topological dimension of limit spaces of normalized sequences of iterated vertex replacements involving more than one replacement graph. We also give examples of vertex replacement rules that yield fractals.

On parallel machine replacement problems with general replacement cost functions and stochastic deterioration

AbstractThe parallel machine replacement problem consists of finding a minimum cost replacement policy for a finite population of economically interdependent machines. In this paper, we formulate a stochastic version of the problem and analyze the structure of optimal policies under general classes of replacement cost functions. We prove that for problems with arbitrary cost functions, there can be optimal policies where a machine is replaced only if all machines in worse states are replaced (Worse Cluster Replacement Rule). We then show that, for problems with replacement cost functions exhibiting nonincreasing marginal costs, there are optimal policies such that, in any stage, machines in the same state are either all kept or all replaced (No‐Splitting Rule). We also present an example that shows that economies of scale in replacement costs do not guarantee optimal policies that satisfy the No‐Splitting Rule. These results lead to the fundamental insight that replacement decisions are driven by marginal costs, and not by economies of scale as suggested in the literature. Finally, we describe how the optimal policy structure, i.e., the No‐Splitting and Worse Cluster Replacement Rules, can be used to reduce the computational effort required to obtain optimal replacement policies. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005

An Operational Semantics of CommUnity Based on Graph Transformation Systems

We propose an operational semantics, based on graph transformation, of CommUnity, a simple program design language. Each action of a single CommUnity design is modeled by a synchronized hyperedge replacement rule. Synchronized actions of several interconnected designs in a configuration result automatically from the individual rules thanks to the rule synchronization mechanism.

A Procedure to Calculate Logic Programs by Replacement with the Bodies of Rules and Transformation to Disjunctive Normal Forms

In this paper, we describe the completeness of a calculation procedure of logic programs. The procedure is the combination of two procedures, a replacement procedure of atoms in the goal by the bodies or the negation of the bodies of rules in the program, and a transformation procedure of equations to disjunctive normal forms (DNF) equivalent under Clark's Equational Theory (CET). To combine replacement of atoms in the goal to logical formulae determined from the program and transformation of equations to DNF equivalent under CET is a method by which procedures with the capability of expressing answers in DNF can be build, so it is a leading method for expressing answers in a form including negation. Some procedures based on the method are devised, and their calculation capabilities are shown by applying the theory of completed programs. However, the procedure that uses the bodies or the negation of the bodies of rules for replacement has higher calculation capability, and is intuitively more natural than they. Therefore, to clarify the calculation capability of the procedure is considered an important subject for research into calculation procedures of logic programs with the capability for expressing answers in a form including negation. Moreover, since the completeness is realized by standing on the viewpoint of treating the implication symbol as a different implication symbol from usual, and interpreting logic programs in three-valued logic, examples which support the viewpoint are also described.