A Tabu-Search Hyperheuristic for Timetabling and Rostering

Hyperheuristics can be defined to be heuristics which choose between heuristics in order to solve a given optimisation problem. The main motivation behind the development of such approaches is the goal of developing automated scheduling methods which are not restricted to one problem. In this paper we report the investigation of a hyperheuristic approach and evaluate it on various instances of two distinct timetabling and rostering problems. In the framework of our hyperheuristic approach, heuristics compete using rules based on the principles of reinforcement learning. A tabu list of heuristics is also maintained which prevents certain heuristics from being chosen at certain times during the search. We demonstrate that this tabu-search hyperheuristic is an easily re-usable method which can produce solutions of at least acceptable quality across a variety of problems and instances. In effect the proposed method is capable of producing solutions that are competitive with those obtained using state-of-the-art problem-specific techniques for the problems studied here, but is fundamentally more general than those techniques.     

An unusual substituent effect in a cycloaddition of an azolium ylide 1,3-dipole: An inverted V-shaped hammett plot

An unusual inverted V-shaped Hammett plot has been observed for substituent effects at the N-terminus of 1,2,3-triazolium-1-imide 1,3-dipoles in cycloaddition reactions. Theoretical studies (3-21G and 6-31G) suggest strong resonance interactions separately stabilizing both ends of the dipole.     

Theoretical study of possible products of the combination of H2O and HCN

Twenty-two structures with the empirical formula H₃CNO are presented. These structures are examined since they have the same formula as the H₂O…HCN complex. The H₂O…HCN potential energy surface is of interest to chemists studying the water catalyzed polymerization of HCN. Structures, thermodynamics, and vibrational spectra are examined.     

Functional characterizations of certain p-spaces

In this paper we prove that p-spaces and ?ech-complete spaces with G_δ-diagonals can be characterized by a familiar function extension property.     

On the multivariate two-sample problem using strong approximations of the EDF

The recently developed strong approximation methods are discussed and applied to the problem of testing whether two independent multivariate samples come from the same population and whether the components of the observations are independent. The usual Cramér-von Mises statistic, as well as one based on the difference between the sum of the two multivariate EDF's and twice the product of the marginal EDF's of one, are studied. A fairly sensitive integral statistic is also discussed. Consistency and some asymptotic power properties are explored. Emphasis is placed on explication of the strong approximation methodology.     

A correction to and improvement of ‘Strong approximations of some biometric estimates under random censorship’

Summary In the proof of the main result of the original paper there is an error. Instead of repairing that proof to get just the original result, at the critical spot we improve the proof and obtain a much better result. In particular, we approximate the product-limit and empirical cumulative hazard processes by suitable copies of the corresponding limiting Gaussian processes with rates of approximation that on appropriate fixed half lines reduce to the rates of Komlós, Major and Tusnády for the uncensored empirical process.     

Ionophore synthesis. An enantioselective route to the left-wing of indanomycin (X- 14547A).

An enantioselective synthesis of the tetrahydropyran “left-wing” ofthe ionophore X-14547A is described, wherein stereoselective 1,2-carbonyl additions and an oxapyronone-to-dihydropyran enolate Claisen rearrangement are key stereocontrol elements.     

Student Performance on Asking Questions,Identifying Variables,and Formulating Hypotheses

The purpose of this study was to extend attempts to develop a research framework for encoding and analyzing students' responses to the tasks of asking questions, identifying variables, and formulating hypotheses, and to use the research framework to analyze and classify the responses of seventh grade students. A performance-based assessment instrument was used. The topic was heat and temperature. The responses of 364 seventh grade students were used to develop a framework for evaluating student written responses which allows researchers to classify student responses according to their general completeness and usefulness, and according to the manner in which responses were incomplete or not useful. Interrater reliability was 82%. Seventh grade students who reportedly have had instruction in the science processes did not perform well on this performance-based assessment.     

Spectrophotometric determination of palladium with 1-thioglycerol and a study of palladium complex formation with four similar thio-organic compounds

A study of the reactivity of five thio-organic compounds with palladium^II ions has been made and one of them, 1-thioglycerol, selected for use as a spectrophotometric reagent for palladium. Its sensitivity is 0.01 μg of palladium/cm² for log I₀/I = 0.001. The sensitivity of the other four compounds is about the same. Beer's law is obeyed over the palladium concentration range of 0.5 to 9 ppm. The effects of pH, order of addition of reagents, temperature and diverse ions have been investigated.     

Proton states in theN = 86 nuclei147Pm and149Eu populated in the (3He,d), (α,t) and (t, α) reactions

The (³He,d) and (α, t) reactions on targets of¹⁴⁶Nd and¹⁴⁸Sm have been studied, using beams of 24 MeV³He and 27 MeV⁴He from the McMaster University tandem van de Graaff accelerator. Also the (t, α) reaction on a target of¹⁴⁸Sm has been studied, using 17 MeV tritons from the Los Alamos Scientific Laboratory tandem accelerator. The reaction products were analyzed with magnetic spectrographs. Information on thel-values was obtained from (³He,d) angular distributions and from ratios of (α,t) and (³He,d) cross sections. In each nucleus a severe fragmentation of the shell-model strength is found. In particular a total of 13(7)l=2 transitions and 6(6)l=0 transitions have been identified in¹⁴⁷Pm(¹⁴⁹Eu). The results are analyzed in terms of the spherical shell model, which accounts fairly well for the summed spectroscopic strengths. However, with the existence of the (t, α) data a more detailed investigation of the emptiness of individual levels observed in¹⁴⁷Pm gives some indication that a deformed scheme might be more successful in describing these nuclei.