205099974
Organization of quasi-consecutive retrieval files
Abstract In 1972, Ghosh introduced the consecutive retrieval (CR) file organization. It is an efficient file organization in which all records pertinent to a query are consecutively stored on linear storage locations. In this paper, we introduce the quasi-consecutive retrieval (QCR) file organization. The QCR file organization is an extension of Ghosh's CR file organization and normally offers less redundancy. In the QCR file, all the records pertinent to each query are not necessarily stored consecutively, but rather they are stored within an area of the buffer size. In this paper, we discuss graph theoretic properties of CR files and QCR files by using the properties of interval graphs well known in graph theory. We provide a basic condition for the existence of a QCR file without redundancy for a given buffer size. By introducing redundant queries, such a condition is simplified. Furthermore, a heuristic computer algorithm is given to organize a QCR file with less redundancy for a given buffer size.
18193868
Interval Queries on Object Histories: Extended Abstract
This extended abstract introduces the notion of ’ interval queries ’ on historical data for objects (here, called ‘object histories’) and explores a certain closure property. As for describing historical data for objects, we use our mathematical model introduced in our earlier paper. The major construct in the model is a ‘computation-tuple sequence scheme’ (abbreviated CSS), which specifies the set of all possible ‘valid’ object histories for the same type of object. Interval queries are those queries which return an interval (history) from a given object history. We provide conditions under which an interval query applied to object histories described by one CSS yields, as its answers. the set of all object histories which can be described by another CSS.
1810071
Testing of Join Dependency Preserving by a Modified Chase Method
29360261
Towards Abstracting Complex Database Objects: Generalization, Reduction and Unification of Set-type Objects (Extended Abstract)
Representing and manipulating complex (database) objects are important issues in the semantic database models and object-oriented database models, most of which have a rich expressive power for complex objects. In this paper, we will focus on the manipulation of complex objects, and introduce the notions and the operations for abstracting complex objects. We introduce the notion of "element-based" generalization relationships between complex objects, and two new abstraction operators: reduction and unification. Their algebraic properties are then formally investigated especially for "set-type" complex objects.
22236580
OVID: Design and Implementation of a Video-Object Database System
A video-object data model and the design and implementation of a prototype video-object database system named OVID based on the model are described. Notable features of the video-object data model are a mechanism to share common descriptional data among video-objects, called interval-inclusion based inheritance, and operations to composite video-objects. The OVID system offers a browsing/inspection tool called VideoChart, and adhoc query facility called VideoSQL, and a video-object definition tool. >
5408151
Alternative Objects in Object-oriented Databases
16332479
Preferential Urn Model on a Random Network
A preferential urn model on a random network and a complete graph is studied. The preferential urn model is based on the concept "the rich get richer", and has simple dynamics of ball-transfers. The model is considered as a simple socio-economic system. From analytical treatments, it has been revealed that the preferential urn model on the complete graph gives a fat-tailed occupation distribution in the case with randomness for fitness parameters. In the present paper, using numerical experiments, we show that the model on the random network gives a fat-tailed occupation distribution in the case without randomness for fitness parameters; hence, we would consider that the local ball-transfer process on the random network includes effects corresponding to the randomness for fitness parameters. This simple game would give a valuable insight into various phenomena from socio-economic point of view
35660731
Some Properties of Fuzzy Sets of Type 2
The concept of fuzzy sets of type 2 has been defined by L. A. Zadeh as an extension of ordinary fuzzy sets. The fuzzy set of type 2 can be characterized by a fuzzy membership function the grade (or fuzzy grade) of which is a fuzzy set in the unit interval [0, 1] rather than a point in [0, 1]. This paper investigates the algebraic structures of fuzzy grades under the operations of join ⊔, meet ⊔, and negation ┐ which are defined by using the extension principle, and shows that convex fuzzy grades form a commutative semiring and normal convex fuzzy grades form a distributive lattice under ⊔ and ⊓. Moreover, the algebraic properties of fuzzy grades under the operations and which are slightly different from ⊔ and ⊓, respectively, are briefly discussed.
120935286
Automatic hyperparameter estimation in probabilistic image restoration algorithm based on Gibbs microcanonical distribution
For an original image given as an 8-gray-level image, the framework for image restoration is composed of Bayes statistics for the a priori probability distribution based on the microcanonical distribution. In this process, the a priori probability distribution serving as the microcanonical distribution is formulated on the basis of the variables characterizing the spatial flatness and smoothness of the image in terms of the number of nearest pixel pairs with different gray levels and the number of nearest pixel pairs with gray levels differing by 1. In the present paper, we propose a new method of estimation, from a degraded image, of the number of nearest pixel pairs with different gray levels and the number of nearest pixel pairs with gray levels differing by 1 in the original image. Then, based on that formulation, an iterative computation algorithm for the restoration of a 256-gray-level image is presented from the viewpoint of statistical mechanics. Through some numerical experiments, we investigate how the proposed method can improve the quality of the restored image. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 36(1): 68–78, 2005; Published online in Wiley InterScience (). DOI 10.1002sscj.10365
20447387
Cluster ZTP in the recovery of an image
Abstract Cluster ZTP (zero-temperature process) is proposed as a method of image recovery and examined for 8-valued images. The cluster ZTP is an iterative algorithm for the search of an approximately optimal solution of an energy minimization problem.
3247078
Individual Level Analysis Using Decision Making Features in Multiagent Based Simulation
We introduce a set of evaluation tools in the framework of individual level analysis for multiagent based simulations. These tools are intended to overcome the weak points of multiagent systems: that it is difficult to avoid mistakes in description and arbitrary modeling; and to find reliable explanations of causal relationships between the model and its result. We analyze some artificial market models using an evaluation process that consists of the evaluation of initial learning maturity, discrimination between models, and the visualization of attention tendency in a group. We conclude that these analytical methods are useful for the evaluation of multiagent based simulations in terms of validation and finding causal relations.