Hierarchy Of Domains Research Articles

Domains in the low-temperature phase of magnetite from synchrotron-radiation x-ray topographs

Domains in the low-temperature, ferrimagnetic, and ferroelectric, phase of magnetite ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ were investigated in the bulk, via their ferroelastic distortion, by means of synchrotron radiation x-ray topography, complemented by Nomarski optical microscopy on the surface. After cooling through the Verwey transition under a magnetic field parallel to [001], the images show a hierarchy of domains. Domains associated with a small difference in lattice distortion provide a clear indication that the symmetry is triclinic. They appear as a substructure of monoclinic domains separated by walls creating no long-range stress. The domain structure deduced from the observation, under the experimentally self-tested assumption that the walls involved are stress free, is favorable from the elastic, magnetostatic, and electrostatic points of view.

A hierarchy of constraint systems for data-flow analysis of constraint logic-based languages

Many interesting analyses for constraint logic-based languages are aimed at the detection of monotonic properties, that is to say, properties that are preserved as the computation progresses. Our basic claim is that most, if not all, of these analyses can be described within a unified notion of constraint domains. We present a class of constraint systems that allows for a smooth integration within an appropriate framework for the definition of non-standard semantics of constraint logic-based languages. Such a framework is also presented and motivated. We then show how such domains can be built, as well as construction techniques that induce a hierarchy of domains with interesting properties. In particular, we propose a general methodology for domain combination with asynchronous interaction (i.e., the interaction is not necessarily synchronized with the domains' operations). By following this methodology, interesting combinations of domains can be expressed with all the semantic elegance of concurrent constraint programming languages.

Total objects in inductively defined types

Coherence-spaces and domains with totality are used to give interpretations of inductively defined types. A category of coherence spaces with totality is defined and the closure of positive inductive type constructors is analysed within this category. Type streams are introduced as a generalisation of types defined by strictly positive inductive definition. A semantical analysis of type streams with continuous recursion theorems is established. A hierarchy of domains with totality defined by positive induction is defined, and density for a sub-hierarchy is proved.

Closing the gap between the continuous functionals and recursion in $^3E$

We show that the length of a hierarchy of domains with totality, based on the standard domain for the natural numbers ${\Bbb N}$ and closed under dependent products of continuously parameterised families of domains will be the first ordinal not recursive in $^3E$ and any real. As a part of the proof we show that the domains of the hierarchy share important properties with the types of continuous functionals. The main result can also be viewed as a representation theorem for recursion in $^3E$ .

On magnetic domain configurations in single-crystal, (112)-orientation plates of iron-silicon alloy: some X-ray topographic observations and their interpretation

Possible magnetization states of a cubic ferromagnetic crystal having easy magnetization directions parallel to the cube axes (as in Fe + 3 mass % Si alloy) can be represented using a regular octahedron, as first shown by Néel. This model is developed to derive rules that govern shapes and relative volumes of the differently magnetized domains needed to produce mean magnetization lying in a plane of any orientation. Single-crystal plates of Fe + 3 mass % Si alloy not containing an easy-magnetization direction, such as plates parallel to (112) studied in this work, are in general subdivided into a hierarchy of domains that in spatial scale diminish from specimen interior towards specimen surfaces. X-ray topography offers a non-contacting method of mapping domain configurations. Under appropriate diffraction conditions the strains associated with 90° Bloch walls generate strong diffraction contrast. In X-ray transmission topographs the superimposition of contrast from surface closure domains upon that of inner domains generally gives rise to highly complex images from (112) plates. However, with specimen thicknesses less than 20 μm the patterns can become sufficiently simplified to make possible the identification of shapes and magnetization axes of all domains present. A pattern in this class is illustrated, and interpreted with the aid of the octahedron. Reasonable agreement is found between the observed size scale of the domains and that calculated for minimum energy in the domain structure proposed.

Fine grained object protection in UNIX

In this document we describe and discuss a solution, called UNIX Access Table Protection (UATP), to the problem of providing a secure environment for persistent object types with fine grained protection on a UNIX system. UATP requires no modifications to the UNIX kernel. User's on UNIX have discretionary access control over their directories and files. By using these controls in a particular way, this paper shows a way in which a hierarchy of protection domains can be set up to enable object methods and type instances to be managed securely and to be protected from unauthorised use. The document also describes how a particular object type, a UATP-kernel, which executes in these protection domains (in the same way as all other objects) can be used to provide fine grained protection for all other objects which are installed and running in the manner described here.

Surface Energy Balances of Three General Circulation Models: Implications for Simulating Regional Climate Change

We examine surface energy balances simulated by three general circulation models for current climatic boundary conditions and for an atmosphere with twice current levels of CO2. Differences between model simulations provide a measure of uncertainty in the prediction of surface temperature in a double-CO2 climate, and diagnosis of the energy balance suggests the radiative and thermodynamic processes responsible for these differences. The scale dependence of the surface energy balance is examined by averaging over a hierarchy of spatial domains ranging from the entire globe to regions encompassing just a few model grid points. Upward and downward longwave fluxes are the dominant terms in the global-average balance for each model and climate. The models product nearly the same global-average surface temperature in their current climate simulations, so their upward longwave fluxes are nearly the same, but in the global-average balance their downward longwave fluxes, absorbed solar radiation, and sensible and latent heat fluxes have intermodel discrepancies that are larger than respective flux changes associated with doubling CO2. Despite the flux discrepancies, the globally averaged surface flux changes associated with CO2 doubling are qualitatively consistent among the models, suggesting that the basic large-scale mechanisms of greenhouse warming are not very sensitive to the precise surface balance of heat occurring in a model's current climate simulation. The net longwave flux at the surface has small spatial variability, so global-average discrepancies in surface longwave fluxes are also manifested in the regional-scale balances. For this reason, increasing horizontal resolution will not improve the consistency of regional-scale climate simulations in these models unless discrepancies in global-average longwave radiation are resolved. Differences between models in simulating effects of moisture in the atmosphere and in the ground appear to be an important cause of differences in surface energy budgets on all scales.

Network Models to Describe the Kilivila Classifier System

The system of classificatory in the Kilivila language of the Trobriand Islands (originally described by Malinowski in 1920) is examined in detail. The 88 particles studied can be seen as operating dynamically within 20 semantic domains, with much potential for substitution of particles within and between domains available to speakers in discourse. Variable rules are developed with relative frequencies for the choice of individual particles in a given domain. When the substitution possibilities are plotted in two dimensions, a type of network results. The question as to whether there is a valid hierarchy of domains and whether the network might consist of more than two dimensions is also considered.

Transformations and Abstract Presentations in a Language Development Environment

A syntax-directed editing environment intended for development of artificial languages, e.g. programming languages, specification languages, and grammar definition languages, is presented. Various applications of a simple, syntactic transformation facility is central to the work. There is a description of how most syntax-directed editing operations can be implemented and understood as transformations. It is furthermore demonstrated how documents, which are represented as abstract syntax trees, can be kept consistent with a grammar that is under development. A multi-formalism transformation technique is also described. Abstract presentation of documents on a screen is another central topic. Two simple presentation formalisms that allow documents to be shown as trees and graphs are proposed. As a basis for the whole work, a new formalism for description of context-free languages has been worked out. The formalism is based on generalization/specialization hierarchies of syntax domains.

Functional complementation between mutations in a yeast suppressor tRNA gene reveals potential for evolution of tRNA sequences.

Successive rounds of mutagenesis of a Schizosaccharomyces pombe strain bearing the UGA-reading sup3 tRNASer suppressor have been carried out for two cycles of inactivation and reactivation of the suppressor. The suppressor phenotype at each stage was found to involve different combinations of three mutations, A30, A53, and A67, in the sup3-UGA gene. Single mutations A30 and A53 inactivate the suppressor as does the presence of all three mutations. A67 by itself is phenotypically neutral, but in combination with either A30 or A53 suppressor function is restored. The frequency with which these and other complementation events occur in S. pombe demonstrates a significant potential for nucleotide sequence evolution in tRNA. Differential expression of the S. pombe genes in Saccharomyces cerevisiae suggests that the two yeasts have diverged at the transcriptional and RNA processing level. Processing of the mutant tRNA precursors in S. cerevisiae reveals a hierarchy of structural domains within the tRNA that vary in their importance for RNase P cleavage.

Psychometric and instructional validation of hierarchical domain structures

Six hundred twenty-six subjects from the University of Arizona participated in an investigation designed to examine congruence of a math domain hierarchy validated psychometrically and validated instructionally. The hierarchy consisted of quadratic and cubic equation tasks. Three studies comprised the investigation. Study 1 validated a hierarchy of quadratic and cubic equation domains psychometrically. Studies 2 and 3 instructionally validated domains and prerequisite relations identified in Study 1 and examined generalization and transfer between subordinate and superordinate skills within and between domains. The investigation revealed congruence between hierarchies validated psychometrically and instructionally. In addition, generalization and transfer were revealed within and between domains. The implications for hierarchical sequencing and instructional technology were discussed.

Domain names (panel session, abstract only)

The DARPA Domain Name project is an attempt to move from a centralized naming authority to a distributed one. In essence, the domain system computes a single binding from a character string known as a host name to another string known as the host address (a 32-bit integer). Besides the syntactic changes in names, the chief difference between the old-style names and domain names is that in the old system, a database containing the name-to-address bindings was distributed to each host where bindings were performed locally, while in the domain system computation of the name-to-address binding uses the internet to contact search the hierarchy of domains until a server is found that can perform the binding. Unfortunately, to make the system efficient, servers cache bindings they look up, and clients begin a search by contacting the nearest “leaf” server to avoid searching the hierarchy. If sufficient memory is available, the cache at a server corresponds exactly to old-style host tables. The domain scheme raises other questions. In principle, the hierarchical structure of domain names permits easy delegation of naming authority because it allows names within independent subtrees to be assigned by independent organizations. In practice, however, the hierarchical scheme collects together organizations under fixed top-level domains. Because extremely small organizations cannot afford to maintain a domain name server, they must be supported by (and obey the authority of) a domain server for the subhierarchy under which they lie. A hierarchical organization of names also imposes restrictions on the use of the system. For example, even though domain name servers contain (name, address) pairs, it is impossible to locate the desired binding given only the address.

Naming and addressing in a computer-based mail environment

In a computer-based mail environment, digital addresses (i.e., the equivalent of telephone numbers) are sufficient to allow the mail system to perform forwarding and delivery. However, digital addresses are not easily remembered by people and some of the intelligence inherent in the system must be used to provide a more humanly engineered addressing scheme. This paper proposes a two-stage approach. In the first stage, a set of attributes (names, postal address, company affiliation, etc.) is mapped into an identifier which designates a single originator or recipient (O/R) of mail. This mapping is performed via a database query dialog and is executed prior to the posting of a mail item. The O/R identifier designates an O/R invariant to its current location and is the primary information by which the mail system decides to whom mail must be delivered. In the second stage, the mail system converts the O/R identifier into an address which is then used by the mail system for forwarding and delivery. The paper discusses the relationship between a hierarchy of authority domains and the attributes and identifiers. It also analyzes the problems associated with updating the databases that support the two mapping functions. In addition, methods are developed that allow the mail system to deliver mail items correctly even under the assumption that not all databases involved contain accurate information.

The Structure of Domain Hierarchies Found Within a Domain Referenced Testing System

The purpose of this study was to assess conditional states of item mastery found among items from different item domains and the effectiveness of various procedures for identifying such conditional relations. The item domains considered were from the curriculum area of multiplication of whole numbers, and were defined by a domain referenced testing system. It was possible to infer from the results of this study that the domain referenced testing system considered produced items which across domains showed strong conditional relations. Comparisons of goodness of fit were made among domain hierarchies with similar numbers of specified conditional relations generated by two different empirical procedures and by experts judgment. Additional comparisons were made among models generated by the same procedure but with different numbers of specified conditional relations. Support for the validity of empirically generated hierarchies with moderate numbers of conditional relations among domains was provided. However, similar support was not provided for the conditional relations hypothesized to exist by subject matter experts.