Knowledge-based machine vision systems for space station automation

Computer vision techniques which have the potential for use on the space station and related applications are assessed. A knowledge-based vision system (expert vision system) and the development of a demonstration system for it are described. This system implements some of the capabilities that would be necessary in a machine vision system for the robot arm of the laboratory module in the space station. A Perceptics 9200e image processor, on a host VAXstation, was used to develop the demonstration system. In order to use realistic test images, photographs of actual space shuttle simulator panels were used. The system's capabilities of scene identification and scene matching are discussed

A knowledge-based machine vision system for space station automation

A simple knowledge-based approach to the recognition of objects in man-made scenes is being developed. Specifically, the system under development is a proposed enhancement to a robot arm for use in the space station laboratory module. The system will take a request from a user to find a specific object, and locate that object by using its camera input and information from a knowledge base describing the scene layout and attributes of the object types included in the scene. In order to use realistic test images in developing the system, researchers are using photographs of actual NASA simulator panels, which provide similar types of scenes to those expected in the space station environment. Figure 1 shows one of these photographs. In traditional approaches to image analysis, the image is transformed step by step into a symbolic representation of the scene. Often the first steps of the transformation are done without any reference to knowledge of the scene or objects. Segmentation of an image into regions generally produces a counterintuitive result in which regions do not correspond to objects in the image. After segmentation, a merging procedure attempts to group regions into meaningful units that will more nearly correspond to objects. Here, researchers avoid segmenting the image as a whole, and instead use a knowledge-directed approach to locate objects in the scene. The knowledge-based approach to scene analysis is described and the categories of knowledge used in the system are discussed

A graph theoretic approach to scene matching

The ability to match two scenes is a fundamental requirement in a variety of computer vision tasks. A graph theoretic approach to inexact scene matching is presented which is useful in dealing with problems due to imperfect image segmentation. A scene is described by a set of graphs, with nodes representing objects and arcs representing relationships between objects. Each node has a set of values representing the relations between pairs of objects, such as angle, adjacency, or distance. With this method of scene representation, the task in scene matching is to match two sets of graphs. Because of segmentation errors, variations in camera angle, illumination, and other conditions, an exact match between the sets of observed and stored graphs is usually not possible. In the developed approach, the problem is represented as an association graph, in which each node represents a possible mapping of an observed region to a stored object, and each arc represents the compatibility of two mappings. Nodes and arcs have weights indicating the merit or a region-object mapping and the degree of compatibility between two mappings. A match between the two graphs corresponds to a clique, or fully connected subgraph, in the association graph. The task is to find the clique that represents the best match. Fuzzy relaxation is used to update the node weights using the contextual information contained in the arcs and neighboring nodes. This simplifies the evaluation of cliques. A method of handling oversegmentation and undersegmentation problems is also presented. The approach is tested with a set of realistic images which exhibit many types of sementation errors

Sharing Budgetary Austerity under Free Mobility and Asymmetric Information: An Optimal Regulation Approach to Fiscal Federalism

In the present article, Tiebout meets Laffont and Tirole in the land of Fiscal Federalism. We use a non-trivial Principal-Multi-Agent model to characterize the optimal intergovernmental grant schedule, when the cost of local public goods depends on hidden characteristics and actions of local governments, and under citizen free mobility. We show that local governments earn informational rents, and how optimal local taxes, public good production levels and land prices are jointly distorted at the second-best optimum, as a consequence of free mobility and asymmetric information. The effect of informational asymmetries is to decrease the average production of public goods and to increase the inter-jurisdictional variance of taxes and public-good production.asymmetric information, Principal-Agent model, public budget deficits, free-mobility equilibrium, fiscal federalism

Conformational control of anticancer activity: the application of arene-linked dinuclear ruthenium(II) organometallics

Dinuclear metal complexes have emerged as a promising class of biologically active compounds which possess unique anticancer activity. Here, we describe a novel series of arene-linked dinuclear organometallic Ru(II) complexes, where the relative conformation of the ruthenium centres is controlled by the stereochemical configuration of 1,2-diphenylethylenediamine linker moieties, as confirmed by X-ray crystallography. The reactivity and cytotoxicity of these compounds is compared to flexible dinuclear and mononuclear analogues, demonstrating in all cases the complexes can undergo aquation, coordinate to typical biological donor ligands and importantly, in the case of dinuclear analogues, crosslink oligonucleotide and peptide sequences. Differences in the conformation of the isomeric dinuclear compounds lead to significantly different levels of cytotoxicity against A2780, A2780cisR and HEK-293 cell lines; isomers with a closed conformation are significantly more cytotoxic than isomers with a more open conformation and they are also significantly less susceptible to acquired resistance mechanisms operating in the A2780cisR cell line. These rigid dinuclear compounds possess markedly increased cytotoxicity relative to the non-cytotoxic mononuclear analogues that does not appear to be related to differences in complex lipophilicity or cellular uptake, which, in general, remain similar in magnitude across the series. Thus, the molecular conformation of such dinuclear species may be crucial in determining the nature of the adducts formed on coordination to biological targets in a cellular environment, and opens up a novel route toward the development of more active metal-based anticancer agents

The Impacts of the Climate Change Levy on Manufacturing: Evidence from Microdata

We estimate the impacts of the Climate Change Levy (CCL) on manufacturing plants using panel data from the UK production census. Our identification strategy builds on the comparison of outcomes between plants subject to the CCL and plants that were granted an 80% discount on the levy after joining a Climate Change Agreement (CCA). Exploiting exogenous variation in eligibility for CCA participation, we find that the CCL had a strong negative impact on energy intensity and electricity use. We cannot reject the hypothesis that the tax had no detrimental effects on economic performance and on plant exit.

The Impacts of the Climate Change Levy on business: Evidence from Microdata

We estimate the impacts of the Climate Change Levy (CCL) on manufacturing plants using panel data from the UK production census. Our identification strategy builds on the comparison of outcomes between plants subject to the CCL and plants that were granted an 80% discount on the levy after joining a Climate Change Agreement (CCA). Exploiting exogenous variation in eligibility for CCA participation, we find that the CCL had a strong negative impact on energy intensity and electricity use. We cannot reject the hypothesis that the tax had no detrimental effects on economic performance and on plant exit.Climate policy, carbon tax, United Kingdom, manufacturing, impact assessment