A new view on grasping

Reaching out for an object is often described as consisting of two components that are based on different visual information. Information about the object’s position and orientation guides the hand to the object, while information about the object’s shape and size determines how the fingers move relative to the thumb to grasp it. We propose an alternative description, which consists of determining suitable positions on the object — on the basis of its shape, surface roughness, and so on — and then moving one’s thumb and fingers more or less independently to these positions. We modelled this description using a minimum jerk approach, whereby the finger and thumb approach their respective target positions approximately orthogonally to the surface. Our model predicts how experimental variables such as object size, movement speed, fragility, and required accuracy will influence the timing and size of the maximum aperture of the hand. An extensive review of experimental studies on grasping showed that the predicted influences correspond to human behaviour

Survey of Floating-Point Software Arithmetics and Basic Library Mathematical Functions

Abstract Not Provided

PASLIB programmer's guide for the finite element machine, revision 2.1-A

PASLIB is a library of Pascal callable subroutines designed to give application programs access to the unique architectural features of the Finite Element Machine and to the software support services provided by the Nodal Exec operating system which runs on it. The PASLIB subroutines are documented and the procedures needed to write Pascal programs for execution on the Finite Element Machine are defined. Considerations for obtaining optimum hardware and software performance are given. A brief overview of debugging and performance analysis capabilities available to the programmer is presented

Abstract Algebra: An Inquiry-Based Approach, Second Edition, Supplemental Material

This text is a supplement to Abstract Algebra: An Inquiry-Based Approach, Second Edition. It includes applications of algebra to RSA encryption, check digits, the games of NIM and the 15 Puzzle, and the determination of groups of small order. In addition, reference material that could be useful for some students appears in the appendices, such as background material on functions, methods of proof (including the equivalencies of the Well-Ordering Principle and different versions of mathematical induction), and complex roots of unity. The appendices also contain a complete proof that polynomial rings are rings, a proof of the Fundamental Theorem of Algebra, and a derivation of the formula for solving any cubic equation.https://scholarworks.gvsu.edu/books/1029/thumbnail.jp

Resonantly enhanced and diminished strong-field gravitational-wave fluxes

The inspiral of a stellar mass ($1 - 100\,M_\odot$) compact body into a massive ($10^5 - 10^7\,M_\odot$) black hole has been a focus of much effort, both for the promise of such systems as astrophysical sources of gravitational waves, and because they are a clean limit of the general relativistic two-body problem. Our understanding of this problem has advanced significantly in recent years, with much progress in modeling the "self force" arising from the small body's interaction with its own spacetime deformation. Recent work has shown that this self interaction is especially interesting when the frequencies associated with the orbit's $\theta$ and $r$ motions are in an integer ratio: $\Omega_\theta/\Omega_r = \beta_\theta/\beta_r$, with $\beta_\theta$ and $\beta_r$ both integers. In this paper, we show that key aspects of the self interaction for such "resonant" orbits can be understood with a relatively simple Teukolsky-equation-based calculation of gravitational-wave fluxes. We show that fluxes from resonant orbits depend on the relative phase of radial and angular motions. The purpose of this paper is to illustrate in simple terms how this phase dependence arises using tools that are good for strong-field orbits, and to present a first study of how strongly the fluxes vary as a function of this phase and other orbital parameters. Future work will use the full dissipative self force to examine resonant and near resonant strong-field effects in greater depth, which will be needed to characterize how a binary evolves through orbital resonances.Comment: 25 pages, 6 figures, 4 tables. Accepted to Phys Rev D; accepted version posted here, including referee feedback and other useful comment

Analysing Java Identifier Names

Identifier names are the principal means of recording and communicating ideas in source code and are a significant source of information for software developers and maintainers, and the tools that support their work. This research aims to increase understanding of identifier name content types - words, abbreviations, etc. - and phrasal structures - noun phrases, verb phrases, etc. - by improving techniques for the analysis of identifier names. The techniques and knowledge acquired can be applied to improve program comprehension tools that support internal code quality, concept location, traceability and model extraction. Previous detailed investigations of identifier names have focused on method names, and the content and structure of Java class and reference (field, parameter, and variable) names are less well understood. I developed improved algorithms to tokenise names, and trained part-of-speech tagger models on identifier names to support the analysis of class and reference names in a corpus of 60 open source Java projects. I confirm that developers structure the majority of names according to identifier naming conventions, and use phrasal structures reported in the literature. I also show that developers use a wider variety of content types and phrasal structures than previously understood. Unusually structured class names are largely project-specific naming conventions, but could indicate design issues. Analysis of phrasal reference names showed that developers most often use the phrasal structures described in the literature and used to support the extraction of information from names, but also choose unexpected phrasal structures, and complex, multi-phrasal, names. Using Nominal - software I created to evaluate adherence to naming conventions - I found developers tend to follow naming conventions, but that adherence to published conventions varies between projects because developers also establish new conventions for the use of typography, content types and phrasal structure to support their work: particularly to distinguish the roles of Java field names

Dense Gray Codes in Mixed Radices

The standard binary reflected Gray code describes a sequence of integers 0 to n-1, where n is a power of 2, such that the binary representation of each integer in the sequence differs from the binary representation of the preceding integer in exactly one bit. In September 2016, we presented two methods to compute binary dense Gray codes, which extend the possible values of n to the set of all positive integers while preserving both the Gray-code property such that only one bit changes between each pair of consecutive binary numbers, and the density property such that the sequence contains exactly the n integers 0 to n-1. The first of the two methods produces a dense Gray code that does not have the cyclic property, meaning that the last integer and the first integer of the sequence do not differ in exactly one bit. The second method, based on the first, produces a cyclic dense Gray code if n is even. This thesis summarizes our previous work and generalizes the methods for binary dense Gray codes to arbitrary radices that may either be a single fixed radix for all digits or mixed radices where each digit may be represented in a different radix. We show how to produce a non-cyclic mixed-radix dense Gray code for any set of radices and any positive integer n---that is, a permutation of the sequence \u3c0,1,...,n-1\u3e such that the digit representation of each number differs from the digit representation of the preceding number in only one digit, and the values of the digits that differ is exactly 1. To this end, we provide a simple formula to compute each digit of each number in the permutation in constant time. Though we do not provide such a formula to generate the digits of a cyclic mixed-radix dense Gray code, we do present, for n equal to the product of the radices, a recursive algorithm that computes the entire cyclic mixed-radix Gray code with the density, strict Gray-code, and modular cyclic properties: given a k-tuple of mixed radices r = (r_(k-1),r_(k-2),...,r_0), each of the n integers in the cyclic mixed-radix Gray code differs from its preceding integer-with the first integer differing from the last integer---in only one digit position i, and the values of those digits differ by exactly 1, except for the digits of the first and last numbers, which may also be the integers 0 and r_i-1. For values of n that are less than the product of the radices, we show a list of cases for which we prove it is impossible to generate a mixed-radix dense Gray code that has the modular Gray-code and cyclic properties for a set of mixed radices r and a positive integer n

Navigating the roadblocks to spectral color reproduction: data-efficient multi-channel imaging and spectral color management

Commercialization of spectral imaging for color reproduction will require the identification and traversal of roadblocks to its success. Among the drawbacks associated with spectral reproduction is a tremendous increase in data capture bandwidth and processing throughput. Methods are proposed for attenuating these increases with data-efficient methods based on adaptive multi-channel visible-spectrum capture and with low-dimensional approaches to spectral color management. First, concepts of adaptive spectral capture are explored. Current spectral imaging approaches require tens of camera channels although previous research has shown that five to nine channels can be sufficient for scenes limited to pre-characterized spectra. New camera systems are proposed and evaluated that incorporate adaptive features reducing capture demands to a similar few channels with the advantage that a priori information about expected scenes is not needed at the time of system design. Second, proposals are made to address problems arising from the significant increase in dimensionality within the image processing stage of a spectral image workflow. An Interim Connection Space (ICS) is proposed as a reduced dimensionality bottleneck in the processing workflow allowing support of spectral color management. In combination these investigations into data-efficient approaches improve two critical points in the spectral reproduction workflow: capture and processing. The progress reported here should help the color reproduction community appreciate that the route to data-efficient multi-channel visible spectrum imaging is passable and can be considered for many imaging modalities