The Multi-strand Graph for a PTZ Tracker

High-resolution images can be used to resolve matching ambiguities between trajectory fragments (tracklets), which is a key challenge in multiple-target tracking. A pan–tilt–zoom (PTZ) camera, which can pan, tilt and zoom, is a powerful and efficient tool that offers both close-up views and wide area coverage on demand. The wide area enables tracking of many targets, while the close-up view allows individuals to be identified from high-resolution images of their faces. A central component of a PTZ tracking system is a scheduling algorithm that determines which target to zoom in on, particularly when the high-resolution images are also used for tracklet matching. In this paper, we study this scheduling problem from a theoretical perspective. We propose a novel data structure, the Multi-strand Tracking Graph (MSG), which represents the set of tracklets computed by a tracker and the possible associations between them. The MSG allows efficient scheduling as well as resolving of matching ambiguities between tracklets. The main feature of the MSG is the auxiliary data saved in each vertex, which allows efficient computation while avoiding time-consuming graph traversal. Synthetic data simulations are used to evaluate our scheduling algorithm and to demonstrate its superiority over a naïve one.     

An approximate method for the study of large deformations of membranes

A method is described to give approximate solutions to problems concerned with the deformation of highly extensible, rubberlike membranes. This is based on a principle first described by Rayleigh, involving the minimization of the elastic strain energy of the membrane. The method, which enables rapid solution under a variety of boundary conditions, is applied to three typical problems with no known closed-form solutions, namely: the stretching of a clamped rubber sheet; the stretching of a rubber tube; and the axial movement of the inner ring of an annulus with respect to its outer periphery.     

Allocation of routinely monitored mixing ratios of nitrogen oxides to their sources

In many urban areas throughout the world, the rising mean and peak levels of nitrogen oxides (NOx) are a concern. Road traffic and local industry are usually the major NOx sources in urban environments, buttheir relative contributions to the spatial distribution of the NOx volumetric mixing ratio is normally unknown. This missing piece of information is required for designing effective abatement measures to reduce ambient NOx levels. A new method for estimating the shares of which traffic and industry contribute to the mean ambient NOx mixing ratios observed in urban environments is proposed in this paper. The estimation is based on data obtained by routine air pollution monitoring, using a few assumptions aboutthe temporal emission patterns of NOx and SO2 in the area of study. A set of equations is formulated for the unknown industry and traffic contributions to the NOx mixing ratios at each monitoring site. These equations are solved using the gradient projection optimization method. The bootstrap technique is used to estimate the errors in the process. Spatial maps of the separate shares of industry and traffic in the total ambient NOx levels can be obtained where a sufficient aerial coverage of stations is available. An application of the method to the allocation of NOx mixing ratios to traffic and industrial sources in the Haifa Bay area, Israel, is demonstrated. The results are expected to be useful for future planning of traffic thoroughfares and industrial development in the area.     

When is it Possible to Identify 3D Objects From Single Images Using Class Constraints?

One approach to recognizing objects seen from arbitrary viewpoint is by extracting invariant properties of the objects from single images. Such properties are found in images of 3D objects only when the objects are constrained to belong to certain classes (e.g., bilaterally symmetric objects). Existing studies that follow this approach propose how to compute invariant representations for a handful of classes of objects. A fundamental question regarding the invariance approach is whether it can be applied to a wide range of classes. To answer this question it is essential to study the set of classes for which invariance exists. This paper introduces a new method for determining the existence of invariant functions for classes of objects together with the set of images from which these invariants can be computed. We develop algebraic tests that determine whether the objects in a given class can be identified from single images. These tests apply to classes of objects undergoing affine projection. In addition, these tests allow us to determine the set of views of the objects which are degenerate. We apply these tests to several classes of objects and determine which of them is identifiable and which of their views are degenerate.     

Analysis and enhancement of human–machine interfaces using a joystick controller

This article deals with performance evaluation of human operations in point‐to‐point displacement tasks using a joystick. Analysis of operator outputs during an experimental task revealed a pattern of partially overlapping submovements with predictable velocity characteristics and forms. A velocity‐dependent gain control added to the joystick–cursor interface improved performance when compared to a conventional linear transformation. This control algorithm can be recommended for many similar human–machine interfaces. A specific performance evaluation was applied to estimate the characteristics of different remote control designs. This approach can be used for evaluating human–machine systems. © 2000 John Wiley & Sons, Inc.     

Economic design of offline inspections for a batch production process

We consider a batch production process that can be either stable or unstable, in which inspection is performed offline after production of the batch is completed. The quality of a batch can be estimated with a desired level of certainty by inspecting only a sample of its units. In order to minimise the expected total cost per batch, which includes the costs of inspection, of false acceptance and of false rejection, we propose an economic inspection plan in which only a fraction of the batches, rather than each batch, is inspected. We prove that the expected total cost is a strictly quasiconvex function of the inspection interval. We establish necessary and sufficient conditions for the optimal inspection interval to be finite and propose an efficient algorithm to obtain its value. We demonstrate for the case of a single-sampling plan where the proposed economic approach outperforms the common procedure of inspecting every batch, and the proposed algorithm is very efficient.     

Organic Ag–Hg amalgam composite materials

Amalgams doped with organic molecules represent a new type of triple composite, organics@Ag–Hg. Synthetic procedures involving the dissolution of doped silver in Hg were developed. A detailed study of structure evolution and its dynamics was carried out following the intermediate phases γ-Ag–Hg and ζ-Ag–Hg, and the Ag–Hg solid solution. Three dopants – the dye Congo red (CR), the polymer Nafion and the antibacterial agent chlorhexidine (CH) – were used, indicating the generality of the approach. Detailed release studies of CR served as an additional analytical tool for inspecting the structure dynamics in the forming doped amalgams. Applications, such as for the CH@Ag–Hg amalgam, are pointed out.     

The effect of risk aversion on product family design under uncertain consumer segments

A product family refers to a group of products that have been derived from a common product platform and which are specifically designed to satisfy a variety of market segments. In this paper, we consider a firm utilising product family design in order to respond to the requirements of two consumer segments, each characterised by different quality valuations. Although the total number of consumers in the market is known, the proportions each segment share are random, with known mean and variance. We show how the uncertainty of the market segmentation affects the firm's decision whether to use common rather than unique components. Motivated by a problem faced by a major automotive manufacturer, we study the consequence of low and high uncertainty, various product quality levels and the difference of marginal valuation on the best configuration.     

Hemolymph amino acid analysis of individual Drosophila larvae

One of the most widely used transgenic animal models in biology is Drosophila melanogaster, the fruit fly. Chemical information from this exceedingly small organism is usually accomplished by studying populations to attain sample volumes suitable for standard analysis methods. This paper describes a direct sampling technique capable of obtaining 50-300 nL of hemolymph from individual Drosophila larvae. Hemolymph sampling performed under mineral oil and in air at 30 s intervals up to 120 s after piercing larvae revealed that the effect of evaporation on amino acid concentrations is insignificant when the sample was collected within 60 s. Qualitative and quantitative amino acid analyses of obtained hemolymph were carried out in two optimized buffer conditions by capillary electrophoresis with laser-induced fluorescence detection after derivatizing with fluorescamine. Thirteen amino acids were identified from individual hemolymph samples of both wild-type (WT) control and the genderblind (gb) mutant larvae. The levels of glutamine, glutamate, and taurine in the gb hemolymph were significantly lower at 35%, 38%, and 57% of WT levels, respectively. The developed technique that samples only the hemolymph fluid is efficient and enables accurate organism-level chemical information while minimizing errors associated with possible sample contaminations, estimations, and effects of evaporation compared to the traditional hemolymph-sampling techniques.