Search

A lower bound on the average performance of a total-value greedy heuristic for the integer knapsack problem is derived. It is shown that the average performance bound for the total-value heuristic dominates the corresponding bound for the density-ordered greedy heuristic.

Abstract Shapes are considered as finite arrangements of spatial elements from among points, line and plane segments, circles and ellipses, (circular) arcs, quadratic Bezier curves, of limited but non-zero measure, in 2D and 3D. Augmented shapes are defined as shapes augmented with attributes, e.g., labels, weights, colors, enumerative values, and (parametric) descriptions. Different attribute types specify different behaviors under operations of sum, product and difference and a part relationship. We review different shape–attribute propositions from the shape grammar literature and characterize them uniformly. This uniform characterization of augmented shapes is intended to assist in formalizing new shape–attribute propositions that may have been visually conceived. Highlights • A uniform characterization of different shape-attribute propositions is presented. • A uniform description of the behavior of shapes with attributes is proposed. • Characterizations of attribute types and spatial element types are almost uniform. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we examine the problem of determining the self-duality of a monotone boolean function in disjunctive normal form (DNF). We show that the self-duality of monotone boolean functions with n disjuncts such that each disjunct has at most k literals can be determined in time. This implies an algorithm for determining the self-duality of -DNF functions. We also consider the version where any two disjuncts have at most c literals in common. For this case we give an algorithm for determining self-duality. [Copyright &y& Elsevier]

Abstract: The objective of this study was to distinguish within a population of patients with and without breast cancer. The study was based on the University of Wisconsin''s dataset of 569 patients, of whom 212 were subsequently found to have breast cancer. A subset-conjunctive model, which is related to Logical Analysis of Data, is described to distinguish between the two groups of patients based on the results of a non-invasive procedure called Fine Needle Aspiration, which is often used by physicians before deciding on the need for a biopsy. We formulate the problem of inferring subset-conjunctive rules as a 0–1 integer program, show that it is NP-Hard, and prove that it admits no polynomial-time constant-ratio approximation algorithm. We examine the performance of a randomized algorithm, and of randomization using LP rounding. In both cases, the expected performance ratio is arbitrarily bad. We use a deterministic greedy algorithm to identify a Pareto-efficient set of subset-conjunctive rules; describe how the rules change with a re-weighting of the type-I and type-II errors; how the best rule changes with the subset size; and how much of a tradeoff is required between the two types of error as one selects a more stringent or more lax classification rule. An important aspect of the analysis is that we find a sequence of closely related efficient rules, which can be readily used in a clinical setting because they are simple and have the same structure as the rules currently used in clinical diagnosis. [Copyright &y& Elsevier]

The dynamic Pickup and Delivery Problem with Time Windows (PDPTW) is faced by courier companies serving same-day pickup and delivery requests for the transport of letters and small parcels. This article focuses on the dynamic PDPTW for which future requests are not stochastically modelled or predicted. The standard solution methodology for the dynamic PDPTW is the use of a rolling time horizon as proposed by Psaraftis. When assigning a new request to a vehicle it may be preferable to consider the impact of a decision both on a short-term and on a long-term horizon. In particular, better managing slack time in the distant future may help reduce routing cost. This paper describes double-horizon based heuristics for the dynamic PDPTW. Computational results show the advantage of using a double-horizon in conjunction with insertion and improvement heuristics. [Copyright &y& Elsevier]

Energy assessment of buildings is important to many applications including energy labeling and building retrofit strategies. However, thermal transmittance, which is key to energy assessment, poses a challenge for in-situ evaluation. To address this, we present an exploration of theoretical and experimental data correlating thermal conductivity and dielectric properties of multilayered assemblies consisting of wood-frame construction materials. We experimentally found an R2 score of 0.88 between thermal conductivities and dielectric constants for 26 small-sized assemblies. We predicted their thermal conductivity based on dielectric properties and obtained an R2 score of 0.95 between experimental and predicted results. • Experimental study correlating physical properties of multilayered materials. • Strong correlation between thermal conductivity and dielectric properties found. • Dielectric properties used to infer thermal conductivity of multilayered assemblies. • Showed potential to use dielectric properties for buildings energy assessment. [ABSTRACT FROM AUTHOR]