A fuzzy set-based approach to origin–destination matrix estimation in urban traffic networks with imprecise data

An important issue in the management of urban traffic networks is the estimation of origin–destination (O–D) matrices whose entries represent the travel demands of network users. We discuss the challenges of O–D matrix estimation with incomplete, imprecise data. We propose a fuzzy set-based approach that utilises successive linear approximation. The fuzzy sets used have triangular membership functions that are easy to interpret and enable straightforward calibration of the parameters that weight the discrepancy between observed data and those predicted by the proposed approach. The method is potentially useful when prior O–D matrix entry estimates are unavailable or scarce, requiring trip generation information on origin departures and/or destination arrivals, leading to multiple modelling alternatives. The method may also be useful when there is no O–D matrix that can be user-optimally assigned to the network to reproduce observed link counts exactly. The method has been tested on some numerical examples from the literature and the results compare favourably with the results of earlier methods. It has also been successfully used to estimate O–D matrices for a practical urban traffic network in Brazil.     

Photogalvanic cells: Part X. The transparent disc electrode and the iron-thionine system

The kinetics of the iron-thionine system have been investigated using the transparent rotating disc electrode and flash electrolysis. Using the transparent disc electrode, from the results for the variation of photocurrent with rotation speed and irradiance, we can find the quantum efficiency for the production of semithionine, the efficiency for producing leucothionine from semithionine and the rate constant for the back reaction of leucothionine with Fe(III). This rate constant is also determined from the flash electrolysis experiments. The values of the kinetic parameters are found to be in good agreement with values determined by analysis of the photostationary state, flash photolysis and ac modulation at a transparent disc electrode. The relative merits of the different techniques for investigating photogalvanic systems are discussed.     

Rapid electrochemical assay for theophylline in whole blood based on the inhibition of bovine liver alkaline phosphatase

A disposable electrochemical test strip for determining clinically relevant concentrations of theophylline (0–300 μM) in whole blood is described, based on the generation of p-aminophenol from p-aminophenyl phosphate by the action of bovine liver alkaline phosphatase. Theophylline is an uncompetitive inhibitor of alkaline phosphatase and thus inhibits this process. The test strip consists of a screen-printed, carbon-based electrode system containing the enzyme and substrate in separate layers. Application of a 20-μl blood sample to the strip initiates the enzymic reaction, which will proceed to an extent that is inversely dependent on the amount of theophylline in the sample. After a 2-min incubation, the p-aminophenol generated is quantified by its electrochemical oxidation at + 150 mV (vs. Ag/AgCl) on the underlying carbon electrode. Caffeine and theobromine (0–1 mM), phenylalanine (< mM) and endogenous alkaline phosphatase (<2 U ml ^?1) do not interfere.     

An algorithm and upper bounds for the weighted maximal planar graph problem

In this paper, we investigate the weighted maximal planar graph (WMPG) problem. Given a complete, edge-weighted, simple graph, the WMPG problem involves finding a subgraph with the highest sum of edge weights that is maximal planar, namely, it can be embedded in the plane without any of its edges intersecting, and no additional edge can be added to the subgraph without violating its planarity. We present a new integer linear programming (ILP) model for this problem. We then develop a cutting-plane algorithm to solve the WMPG problem based on the proposed ILP model. This algorithm enables the problem to be solved more efficiently than previously reported algorithms. New upper bounds are also provided, which are useful in evaluating the quality of heuristic solutions or in generating initial solutions for meta-heuristics. Computational results are reported for a set of 417 test instances of size varying from 6 to 100 nodes including 105 instances from the literature and 312 randomly generated instances. The computational results indicate that instances with up to 24 nodes can be solved optimally in reasonable computational time and the new upper bounds for larger instances significantly improve existing upper bounds.     

A decision aid for milk tanker run allocation

This paper reports on a decision aid that recommends solutions to a particular vehicle allocation problem occurring in the New Zealand dairy industry. The decision aid has been developed for use by New Zealand milk tanker schedulers. It is designed to aid them in the allocation of tankers to milk collection routes in order to alleviate pumping bay congestion, which occurs when the tankers return to unload milk at a processing plant. It enables its users to remain in control of the tanker allocation process, while using their own experience and preferences. The paper describes the issues involved and the type of help that the schedulers need. It introduces a typical allocation problem and describes some heuristics for its solution, which are incorporated in the decision aid.     

The infrared spectra (500–140 cm−1) of some diazine complexes of first transition series metal(II) ions

Thirty complexes of some diazines, i.e. pyrazine, pyrimidine and pyridazine, with metal(II) ions of the first transition series have been prepared and their infrared spectra determined. Assignments for metal-ligand modes are proposed on the basis of the band shifts induced by deuteration of pyrazine and by the effects of metal ion and halide substitution. The structural implications of the spectra are discussed.     

SINGLE MACHINE SCHEDULING WITH CONTROLLABLE PROCESSING TIMES AND COMPRESSION COSTS ： PROOF OF THEOREMS

This report is virtually the appendix part of the author‘s previous paper which ineludes the proofs for the theorems and lemmas.     

The infrared spectra of imidazole complexes of platinum(II) halides and nitrite

Summary The i.r. spectra (4000-90 cm^–1) of the [Pt(Him)₄]X₂ complexes (Him = imidazole, X = Cl, Br or I) andcis- andtrans-[Pt(Him)₂X₂] (X = Cl, Br, I or NO₂) and their D₃-labelled analogues have been determined. The distinction between the ring and C-H (or N-H) modes of imidazole is based on the relative shifts which these bands undergo on D₃-labelling. Assignments, based on the effects of imidazole deuteriation and halide substitution, are provided for the v(Pt-Him) and v(Pt-X) modes.     

DNA-binding affinities of MyoD and E47 homo- and hetero-dimers by capillary electrophoresis mobility shift assay

A simple capillary electrophoresis mobility shift assay (CEMSA), with no gel and uncoated capillaries, for the accurate determination of protein-DNA affinities free in solution was applied to constructs of the MyoD/E47 DNA-binding proteins. The determined affinities are compared to those obtained by EMSA. MyoD-E47 covalent heterodimer binds DNA more tightly (Kd=1.8 nM) than MyoD (Kd=14.2 nM) or E47 (Kd= 11.5 nM) covalent homodimers. The effect of non-specific DNA on binding affinities was more important than salt concentration in the MyoD/E47 series. Application of this method to the MyoD/E47 system demonstrates the generality of our CEMSA.