A Parallel Algorithm for High-Speed Stereo Matching

The goal of stereo vision is the recovery of depth information from the relative lateral displacements in the positions of objects within a pair of images taken from slightly differing viewpoints. While recent stereo matching techniques have yielded improvements in reliability and speed, most of these algorithms fall short of the real-time stereo matching requirements for navigation systems, robot vision, machine inspection, and other areas computer vision where rapid response is critical. Traditionally, matching algorithms have achieved high speeds through algorithm simplification and/or relied on custom hardware. The objective of our work has been the develop of a robust high-speed stereo matcher by exploiting parallel algorithms executing on general purpose SIMD machines. Our approach is based on several existing techniques dealing with the classification and evaluation of matches, the application of ordering constraints, and relaxation-based matching. The techniques have bene integrated and reformulated in terms of parallel execution on a theoretical SIMD machine. An ideal machine topology for executing this parallel algorithm is identified through complexity analysis. Feasibility is demonstrated by implementation on a commercially available SIMD machine, and its performance compared with that of the idealized machine. Sample results are shown for real and synthetic stereo pairs

A Parallel Algorithm for Incremental Stereo Matching on SIMD Machines

Previous matching algorithms have achieved high speeds through algorithm simplification and/or relied on custom hardware. The objective of our work has been the development a robust high-speed stereo matcher by exploiting parallel algorithms executing on general purpose SIMD machines. Our approach is based on several existing techniques dealing with the classification and evaluation of matches, the application of ordering constraints, and relaxation-based matching. The techniques have been integrated and reformulated in terms of parallel execution on the theoretical SIMD machine. Feasibility is demonstrated by implementation on a commercially available SIMD machine. Its performance is compared with that of the idealized machine

Interactive Complexity Control and High-Speed Stereo Matching

This paper is concerned with the development of a novel approach to edge based stereo matching. In the context of an incremental matching strategy we have replaced the traditional hierarchical (coarse-fine) matching by an approach called complexity control base matching. Our implementation of this method allows the user to select interactively features which (given the context provided by previous matches) are most likely to be matched successfully. The selection is done at the resolution of the original image and employs a rich set of features properties (e.g., edge strength, orientation, length, textures, etc.) which may be used alone and in logical combinations. Both feature selection and feature matching algorithms execute at real-time rates and all interactions are via a stereo workstation

Formal Derivation of Rule-Based Program

This paper describes a formal approach to developing concurrent rule-based programs. Our program derivation strategy starts with a formal specification of the problem. Specification refinement is used to generate an initial version of the program. Program refinement is then applied to produce a highly concurrent and efficient version of the same program. Techniques for the deriving concurrent programs through either specification or program refinement have been described in previous literature. The main contribution of this paper consists of extending the applicability of these techniques to a broad class of rule-based programs. The derivation process is supported by a powerful proof logic, a logic that recently has been extended to cover rule-based programs. The presentation centers around a rigorous and systematic derivation of a concurrent rule-based solution to a classic problem

Formal Verification of Pure Production Systems Programs

Reliability, defined as the guarantee that a program satisfies its specifications, is an important aspect of many applications for which rule-based expert systems are suited. Executing rule-based programs on a series of test cases. To show a program is reliable, it is desirable to construct formal specifications for the program and to prove that it obeys those specifications. This paper presents an assertional approach to the verification of a class of rule-based programs characterized by the absence of conflict resolution. The proof logic needed for verification is already in use by researchers in concurrent programming. The approach involves expressing the program in a language called Swarm, and its specifications as assertions over the Swarm program. Among models that employ rules-based notation, Swarm is the first to have an axiomatic proof logic. A brief review of Swarm and its proof logic is given, along with an illustration of the formal verification method used on a simple rule-based program

Applying Formal Verification Methods to Pure Rule-Based Programs

Reliability, defined as the guarantee that a program satisfies its specifications, is an important aspect of many applications for which rule-based expert systems are suited. Verification refer to the process used to determine the reliability of the rule-based program. Because past approaches to verification are informal, guarantees of reliability cannot fully be made without severely restricting the system. On the other hand, by constructing formal specifications for a program and showing the program satisfies those specifications, guarantees of reliability can be made. This paper presents an assertional approach to the verification of rule-based programs. The proof logical needed for verification is adopted from one already in use by researchers in concurrent programming. The approach involves using a language called Swarm, and requires one to express program specifications as assertions over the Swarm representation of the program. Among models the employ rule-based notation, Swarm is the first to have an axiomatic proof logic

Recent Deforestation Pattern Changes (2000-2017) in the Central Carpathians:A Gray-Level Co-Occurrence Matrix and Fractal Analysis Approach

The paper explores the distribution of tree cover and deforested areas in the Central Carpathians in the central-east part of Romania, in the context of the anthropogenic forest disturbances and sustainable forest management. The study aims to evaluate the spatiotemporal changes in deforested areas due to human pressure in the Carpathian Mountains, a sensitive biodiverse European ecosystem. We used an analysis of satellite imagery with Landsat-7 Enhanced Thematic Mapper Plus (Landsat-7 ETM+) from the University of Maryland (UMD) Global Forest Change (GFC) dataset. The workflow started with the determination of tree cover and deforested areas from 2000–2017, with an overall accuracy of 97%. For the monitoring of forest dynamics, a Gray-Level Co-occurrence Matrix analysis (Entropy) and fractal analysis (Fractal Fragmentation-Compaction Index and Tug-of-War Lacunarity) were utilized. The increased fragmentation of tree cover (annually 2000–2017) was demonstrated by the highest values of the Fractal Fragmentation-Compaction Index, a measure of the degree of disorder (Entropy) and heterogeneity (Lacunarity). The principal outcome of the research reveals the dynamics of disturbance of tree cover and deforested areas expressed by the textural and fractal analysis. The results obtained can be used in the future development and adaptation of forestry management policies to ensure sustainable management of exploited forest areas

Stability mechanisms of a thermophilic laccase probed by molecular dynamics.

Laccases are highly stable, industrially important enzymes capable of oxidizing a large range of substrates. Causes for their stability are, as for other proteins, poorly understood. In this work, multiple-seed molecular dynamics (MD) was applied to a Trametes versicolor laccase in response to variable ionic strengths, temperatures, and glycosylation status. Near-physiological conditions provided excellent agreement with the crystal structure (average RMSD ∼0.92 Å) and residual agreement with experimental B-factors. The persistence of backbone hydrogen bonds was identified as a key descriptor of structural response to environment, whereas solvent-accessibility, radius of gyration, and fluctuations were only locally relevant. Backbone hydrogen bonds decreased systematically with temperature in all simulations (∼9 per 50 K), probing structural changes associated with enthalpy-entropy compensation. Approaching T opt (∼350 K) from 300 K, this change correlated with a beginning "unzipping" of critical β-sheets. 0 M ionic strength triggered partial denucleation of the C-terminal (known experimentally to be sensitive) at 400 K, suggesting a general salt stabilization effect. In contrast, F(-) (but not Cl(-)) specifically impaired secondary structure by formation of strong hydrogen bonds with backbone NH, providing a mechanism for experimentally observed small anion destabilization, potentially remedied by site-directed mutagenesis at critical intrusion sites. N-glycosylation was found to support structural integrity by increasing persistent backbone hydrogen bonds by ∼4 across simulations, mainly via prevention of F(-) intrusion. Hydrogen-bond loss in distinct loop regions and ends of critical β-sheets suggest potential strategies for laboratory optimization of these industrially important enzymes