Combining constraints and data-flow in a visual query language

Data mining is the discovery of knowledge and useful information from the large amounts of data stored in databases. The emerging data mining tools and systems lead to the demand of a powerful data mining query language. The concepts of such a language for relational databases are discussed before. With the increasing popularity of object-oriented databases, it is important to design a data mining query language for such databases. The main objective of this paper is to propose an Object Data Mining Query Language (ODMQL) for object-oriented databases as an extension to the Object Query Language (OQL) proposed by the Object Data Management Group (ODMG) as a standard query language for object-oriented databases. The proposed language is implemented as a feature of an experimental object-oriented database management system that is developed as a testbed for research issues of object-oriented databases.

For multimedia databases, there are not only different media types, but also different ways to query the databases. The query mechanisms may include free text search, SQL-like querying, icon-based techniques, querying based upon the entity-relationship (ER) diagram, content-based querying, sound-based querying, as well as virtual-reality (VR) techniques. We will first discuss query languages for multimedia databases with emphasis on visual query languages, and then survey recent advances in query languages for heterogeneous multimedia databases and data sources. A powerful spatial/temporal query language called ΣQL is described, and we will illustrate this approach by data fusion examples.

In this paper we introduce DOODLE, a new visual and declarative language for object-oriented databases. The main principle behind the language is that it is possible to display and query the database with arbitrary pictures . We allow the user to tailor the display of the data to suit the application at hand or her preferences. We want the user-defined visualizations to be stored in the database, and the language to express all kinds of visual manipulations. For extendibility reasons, the language is object-oriented. The semantics of the language is given by a well-known deductive query language for object-oriented databases. We hope that the formal basis of our language will contribute to the theoretical study of database visualizations and visual query languages, a subject that we believe is of great interest, but largely left unexplored.

Path expressions have been accepted for concisely manipulating the nested structures in complex object-oriented query expressions. However, previous visual query languages hardly represent such query expressions in a concise and intuitive way partly due to improper visual representation of path expressions and partly due to lack of well-defined system and semantics of languages. In this paper, we present visual modeling of path expressions in a visual object-oriented database query language called Visual Object-Oriented Query Language (VOQL) which has excellent expressive pourer for sets, simple and intuitive syntax, and well-defined semantics. This is enabled by explicitly specifying the semantics of multi-valued path expressions based on the visual notation capable of representing set relationships in addition to functional relationships. The basic visual constructs called blobs and nested blobs denote sets of objects that path expressions represent while the constructs called binding edges and flattening edges visually simulate the notions of variable binding and dot functions in path expressions respectively. Based on the constructs, the grammar of VOQL defines the syntactic components while the semantics of query expressions are provided by syntax-directed translation to the counterparts in the extended relational calculus. Also, the visual constructs allow modeling of restricted universal quantification with a visual scoping box and effectively represent nested quantification and recursive queries without semantic ambiguities.

Network teaching is to use computer equipment and Internet technology in the virtual space, through a certain method to implement the teaching method on the network, the perfection of the network teaching system can directly replace the traditional teaching method in the whole process of teaching. In order to solve the problem of system development, this paper carries out the demand analysis. First, the use of data flow graph technology, depicting information flow and data from the input to the output of the process of transformation; and then, the use of data dictionary technology, defining the relevant elements of the data flow diagram; finally, the use of tree structure diagram is represented by the administrator subsystem, teacher subsystem and student subsystem structure of the system. The requirement analysis system design the bridge of analysis and software, has laid a foundation for the system development.

The ULowell Data Flow Project combines dataflow hardware, dataflow software, and a data flow development environment. The hardware component, a data flow coprocessor card, utilizes seven NEC 7281 Image Pipelined Processors. Each chip models a static dataflow computation and is programmable. The coprocessor was designed and implemented by ULowell personnel and uses an AMIGA 2000 as a host. The software component currently consists of a library of data flow image processing algorithms and an evolving software development environment. Currently the image processing library includes typical imaging operations such as: edge enhancement, filtering, histogramming, and affine transformation. The software development environment (SDE) is depicted in Figure 1. The SDE contains a Data Flow Graph Editor which programmers use to design their data flow code. The data flow algorithm can then be converted directly into NEC data flow assembly code which is then assembled using the ULowell Data Flow Assembler. The assembler differs from NEC's assembler in that it can produce relocatable code. The object code output of the assembler is given to the Data Flow Resource Manager. The resource manager monitors the available resources within the chips. Thus, if a single process does not totally utilize a chip's table space or memory, then a second process may be concurrently loaded onto the same chip. The ability to have multiple data flow processes coexisting within a single chip is unique to the ULowell environment. The data flow resource manager can download and monitor code to either the hardware or to a software simulator/debugger. The simulator/debugger can monitor and trace data flow tokens as they proceed through the chip. Output of the simulator/debugger can be fed back into the data flow graph editior to visually trace token flow through the original program design. The last component of our SDE is a High Level Language translator which can compile programs written in SISAL, a high level language for parallel computation, down to NEC 7281 assembly language. We have already implemented the relocatable assembler, and the data flow resource manager. Prototype versions of the high level translator, simulator/debugger and graph/editor are currently being implemented.

In this paper we introduce and formally define Query by Browsing (QBB), a scalable, relationally complete visual query language based on the desktop user interface paradigm and tuple relational calculus that allows the formulation of complex queries over relational, entity-relationship, object-oriented and XML data sources on a variety of handheld and desktop platforms. It is to our knowledge the first visual query language to combine the important characteristics of usability, scalability, expressive power and flexibility. We support these claims by demonstrating the similarity of the QBB paradigm to the popular desktop user interface paradigm, by relating it to relational calculus and relational algebra and by describing Chiromancer II, a Web-based implementation of the QBB paradigm for handheld devices. We also discuss ways in which non-relational sources can be represented and queried and compare QBB to related work in the area of visual query languages for a variety of data models. We finally offer conclusions and thoughts for future work.

The visual query language CQL for transitive and relational computation

VOQL*: A Visual Object Query Language With Inductively Defined Formal Semantics

Multimedia data are now available to a variety of users ranging from naive to sophisticated. To make querying easy, visual query languages have been proposed. Most of these languages have a low expressive power and have their own query processors. Efforts have been made to design query languages with proper semantics to facilitate query optimization and processing in existing database systems. The majority of multimedia database systems are built on top of object or object-relational database systems with the underlying query facilities inherited. The DISIMA system is being built on top of a commercial OODBMS and we have chosen to extend the standard object oriented query language OQL with some multimedia functionalities. The resulting language is called MOQL. This paper presents VisualMOQL, a visual query language implementing the image component of MOQL.

Query languages for graph databases started to be investigated some 25 years ago. With much current data, such as linked data on the Web and social network data, being graph-structured, there has been a recent resurgence in interest in graph query languages. We provide a brief survey of many of the graph query languages that have been proposed, focussing on the core functionality provided in these languages. We also consider issues such as expressive power and the computational complexity of query evaluation.

Visual domain-specific languages usually have low entry barrier. Sometimes even children can program on such languages by working with visual representations. This is widely used in educational robotics domain, where most commonly used programming environments are visual. The paper describes a novel dataflow visual programming environment for embedded robotic platforms. Obviously, complex dataflow languages are not simple for understanding. The purpose of our tool is to "bridge" between lightweight educational robotic programming tools (commonly these tools provide languages which are based on control flow model) and complex industrial tools (which provide languages based on more complex dataflow execution model). We compare programming environments mostly used by robotics community with our tool. After brief review of behavioural robotic architectures, some thoughts on expressing them in terms of our dataflow language are given. Visual language, which is described here, provides opportunity to mix dataflow and control flow models for robotics programming. We believe that it is important for educational purposes. Program on our language consists of different blocks (visual representation of data transformation processes) and "links" which presents data flow between them. Domain-specific modelling approach was used to develop our language. Also, this paper provides the examples of solving two typical robot control tasks in our language.

Describes the initial design work of the New Zealand Distributed Information Systems (NZDIS) research project, which seeks to develop an architecture for building distributed information systems from existing information resources, based on software agent and distributed object technologies. An agent-based architecture is used, with messages exchanged via the FIPA (Foundation for Intelligent Physical Agents) agent communication language (ACL). Novel features of this system include the use of standards from the object-oriented programming community, such as the Common Object Request Broker Architecture (CORBA) as a communications infrastructure, the Unified Modeling Language (UML), which is used as an ontology representation language, the Object Data Management Group's Object Query Language (OQL), which is used for queries, and the Object Management Group's Meta Object Facility (MOF), which is used as the basis for an ontology repository agent. 'Stringified' object references may be returned as the content of ACL messages, allowing query results to be made available via a variety of CORBA interfaces.

This paper presents a cost-effective scheme for partitioning large data flow graphs. Standard data flow machine architectures are assumed in this work. The objective is to reduce the overhead due to token transfers through the communication network of the machine. When this scheme is employed on large graphs, the load distribution on the rings of the data flow machine is also improved. A canonical form of a data flow graph is introduced to establish the relationship between the communication overhead and the size reduction of the partition cut-set. General lower estimates on the overhead are derived in terms of processing and transmission delay parameters of the machine. The method uses heuristics and an evaluation function to guide the partition algorithm. Some implications of the proposed method on the organization of the data flow machines are discussed.

A system called net optimization and resource allocation (NORA) is introduced for the evaluation and programming of parallel signal processors, based on a data flow representation of the signal processing application. The main feature of this approach is that the scheduling and resource allocation can be done at compile time. It is made possible by the fact that most signal processing algorithms have constant data flow. The resulting hardware is much simpler because no overhead is needed for the real-time scheduling, as in usual data flow systems. Therefore a realization can easily be obtained using either commercially available components or VLSI technology. The proposed system comprises four main components: (1) a vector oriented data flow compiler for the translation of a high-level language description of algorithms into a data flow graph; (2) a critical path analysis for the evaluation of the minimal computation time of the algorithm, where block scheduling is assumed; (3) a schedule optimization for the determination of the minimal computation time under limited resources, not taking into account limitations imposed by the interconnection structure and temporary storage; and (4) a combined schedule optimization and resource allocation that maps a signal processing application onto a given hardware configuration and generates a formal microprogram.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>