Object-oriented Data Structures Research Articles

Aerodynamic Modeling and Simulation of Multi-Lifting Surfaces Based on the Unsteady Vortex Lattice Method

Using the unsteady vortex lattice method based on the potential flow theory, a rapid modeling approach is developed for the aerodynamic computation of multi-lifting surfaces. Multiple lifting surfaces with different geometric parameters and grid divisions can be quickly integrated and meshed with the object-oriented data structure. The physical influence between different lifting surfaces was modeled, and the wake–surface interaction was also considered by using different built-in vortex core models. The trajectory data were used to replace the pre-calculated downwash superposition for boundary condition integration, and the instantaneous boundary condition was generated directly from the kinematic states and mesh messages of the model concerned. Considering the direct coupling effect between aerodynamics and rigid body dynamics, the function for free flight was built for medium-fidelity dynamic simulations and aerodynamic data identifications. The proposed high-efficiency modeling and simulation process can be easily applied to models with any number of different lifting surfaces and arbitrary motion modes.

Data Integration and Interoperability: Towards a Model-Driven and Pattern-Oriented Approach

Data integration is one of the core responsibilities of EDM (enterprise data management) and interoperability. It is essential for almost every digitalization project, e.g., during the migration from a legacy ERP (enterprise resource planning) software to a new system. One challenge is the incompatibility of data models, i.e., different software systems use specific or proprietary terminology, data structures, data formats, and semantics. Data need to be interchanged between software systems, and often complex data conversions or transformations are necessary. This paper presents an approach that allows software engineers or data experts to use models and patterns in order to specify data integration: it is based on data models such as ER (entity-relationship) diagrams or UML (unified modeling language) class models that are well-accepted and widely used in practice. Predefined data integration patterns are combined (applied) on the model level leading to formal, precise, and concise definitions of data transformations and conversions. Data integration definitions can then be executed (via code generation) so that a manual implementation is not necessary. The advantages are that existing data models can be reused, standardized data integration patterns lead to fast results, and data integration specifications are executable and can be easily maintained and extended. An example transformation of elements of a relational data model to object-oriented data structures shows the approach in practice. Its focus is on data mappings and relationships.

WebPGA: An Educational Technology That Supports Learning by Reviewing Paper-Based Programming Assessments

Providing feedback to students is one of the most effective ways to enhance their learning. With the advancement of technology, many tools have been developed to provide personalized feedback. However, these systems are only beneficial when interactions are done on digital platforms. As paper-based assessment is still a dominantly preferred evaluation method, particularly in large blended-instruction classes, the sole use of electronic educational systems presents a gap between how students learn the subject from the physical and digital world. This has motivated the design and the development of a new educational technology that facilitates the digitization, grading, and distribution of paper-based assessments to support blended-instruction classes. With the aid of this technology, different learning analytics can be readily captured. A retrospective analysis was conducted to understand the students’ behaviors in an Object-Oriented Programming and Data Structures class from a public university. Their behavioral differences and the associated learning impacts were analyzed by leveraging their digital footprints. Results showed that students made significant efforts in reviewing their examinations. Notably, the high-achieving and the improving students spent more time reviewing their mistakes and started doing so as soon as the assessment became available. Finally, when students were guided in the reviewing process, they were able to identify items where they had misconceptions.

PolyFrame, Efficient Computation for 3D Graphic Statics

In this paper, we introduce a structural form finding plugin called PolyFrame for the Rhinoceros software. This plugin is developed based on the methods of 3D Graphic Statics and Polyhedral Reciprocal Diagrams. The computational framework of this plugin uses new robust and efficient algorithms for the creation and modification of complex funicular, compression-only structural forms and is freely available for students, designers, researchers, and practitioners in the fields of architecture, structural engineering, mechanical engineering, and material science. The geometry-based structural design methods are one of the most intuitive yet powerful structural design methods that have recently been extended to 3D based on the Principles of the Equilibrium of Polyhedral Frames. Still, the increased geometrical complexities of the polyhedral diagrams hinder more in-depth practical applications and the research in this field. The framework proposed in this paper can manage, in near real-time, the creation and transformation of reciprocal polyhedral diagrams with a large number of elements as form and force diagrams for structural design purposes. The paper also introduces a hybrid object-oriented data structure that extends and generalizes the previously proposed approaches and thus allows the users to incorporate a variety of different geometric constraints, including edge lengths and the location of the supports from the initial stages of design. Additionally, a new parallel manipulation algorithm is introduced that is capable of transforming polyhedral diagrams while preserving the edge directions and face normal. As a result, a designer can effectively manipulate both structural form and its force distribution without breaking their reciprocity.

Eqtools: Modular, extensible, open-source, cross-machine Python tools for working with magnetic equilibria

As plasma physics research for fusion energy transitions to an increasing emphasis on cross-machine collaboration and numerical simulation, it becomes increasingly important that portable tools be developed to enable data from diverse sources to be analyzed in a consistent manner. This paper presents eqtools, a modular, extensible, open-source toolkit implemented in the Python programming language for handling magnetic equilibria and associated data from tokamaks. eqtools provides a single interface for working with magnetic equilibrium data, both for handling derived quantities and mapping between coordinate systems, extensible to function with data from different experiments, data formats, and magnetic reconstruction codes, replacing the diverse, non-portable solutions currently in use. Moreover, while the open-source Python programming language offers a number of advantages as a scripting language for research purposes, the lack of basic tokamak-specific functionality has impeded the adoption of the language for regular use. Implementing equilibrium-mapping tools in Python removes a substantial barrier to new development in and porting legacy code into Python. In this paper, we introduce the design of the eqtools package and detail the workflow for usage and expansion to additional devices. The implementation of a novel three-dimensional spline solution (in two spatial dimensions and in time) is also detailed. Finally, verification and benchmarking for accuracy and speed against existing tools are detailed. Wider deployment of these tools will enable efficient sharing of data and software between institutions and machines as well as self-consistent analysis of the shared data. Program summaryProgram title: eqtoolsCatalogue identifier: AFBK_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBK_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU GPL v3No. of lines in distributed program, including test data, etc.: 27204No. of bytes in distributed program, including test data, etc.: 1217844Distribution format: tar.gzProgramming language: Python, C.Computer: PCs.Operating system: Linux, Macintosh OS X, Microsoft Windows.RAM: Several megabytes, depends on resolution of dataClassification: 19.4.External routines: F2PY [1], matplotlib [2], MDSplus [3], NumPy [4], SciPy [5]Nature of problem:Access to results from magnetic equilibrium reconstruction code, conversion between various coordinate systems tied to the magnetic equilibrium.Solution method:Data are stored in an object-oriented data structure with human-readable getter methods. Coordinates are converted using bivariate or trivariate splines.Running time:Coordinate transformations on a 66x66 point spatial grid take between 1 and 5 ms per time slice, depending on the transformation used and how many intermediate results have been stored.

Life Cycle Approach to Construction Workspace Modeling and Planning

AbstractWorkspace planning is critical for effective construction planning and control, and workspace modeling is an essential part of computer-aided workspace planning. The existing construction four-dimensional (4D) models, which have gained popularity in construction as an effective tool for planning, control, and communication, lack efficient means to capture the dynamic nature of workspaces to avoid potential workspace conflicts in future construction. This paper presents a life-cycle approach to workspace modeling and planning by first investigating the dynamic nature of the workspace requirements of construction activities and then introducing a conceptual framework to format space usages into life-cycle workspace evolution patterns. Specifically, an object-oriented data structure was designed and implemented to incorporate workspace representation into construction product models, and a workspace identification and adjustment method was created to facilitate the creation of construction workspaces...

A Representation for Local and Global Structures of an Algebraical Bayesian Network in Java Applications

A conjunct ideal with probabilistic estimates of its elements is considered as a knowledge pattern (KP) mathematical model. A set of KPs can be assembled in an algebraical Bayesian network (ABN). We analyze local and global structures of ABNs in order to represent KPs and ABNs as objectoriented data structures in software applications. Our primary scope is Java applications.

X-Plane 및 MATLAB/Simulink 기반의 복수무인기 모의실험 시스템 개발

In this paper, a simulation system based on X-Plane and MATLAB/Simulink for multiple UAVs is presented. For the conceptual design of this proposed system, a hierarchical system architecture for multiple UAVs is presented. This architecture has object-oriented data structure which consists of three objects (UAV status, mission and task, and environment) and a hierarchy consisting of four layers (decision making layer, task assignment layer, path and motion planning layer, and collision avoidance layer) is also proposed. In addition, this paper shows a implementation of simulation system based on the proposed system architecture using X-Plane and MATLAB/Simulink. The result of simulation from the developed system in this paper validate capability of application for multiple UAVs in real environment.

Design and Synthesis for Multimedia Systems Using the Targeted Dataflow Interchange Format

Development of multimedia systems that can be targeted to different platforms is challenging due to the need for rigorous integration between high-level abstract modeling, and low-level synthesis and optimization. In this paper, a new dataflow-based design tool called the targeted dataflow interchange format is introduced for retargetable design, analysis, and implementation of embedded software for multimedia systems. Our approach provides novel capabilities, based on principles of task-level dataflow analysis, for exploring and optimizing interactions across design components; object-oriented data structures for encapsulating contextual information for components; a novel model for representing parameterized schedules that are derived from repetitive graph structures; and automated code generation for programming interfaces and low-level customizations that are geared toward high-performance embedded-processing architectures. We demonstrate our design tool for cross-platform application design, parameterized schedule representation, and associated dataflow graph-code generation using a case study centered around an image registration application.

Object-oriented data structures using Java

Continuing the success of the popular second edition, the updated and revised Object-Oriented Data Structures Using Java, Third Edition is sure to be an essential resource for students learning data structures using the Java programming language. It presents traditional data structures and object-oriented topics with an emphasis on problem-solving, theory, and software engineering principles. Beginning early and continuing throughout the text, the authors introduce and expand upon the use of many Java features including packages, interfaces, abstract classes, inheritance, and exceptions. Numerous case studies provide readers with real-world examples and demonstrate possible solutions to interesting problems. The authors' lucid writing style guides readers through the rigor of standard data structures and presents essential concepts from logical, applications, and implementation levels. Key concepts throughout the Third Edition have been clarified to increase student comprehension and retention, and end-of-chapter exercises have been updated and modified.

Two-Language, Two-Paradigm Introductory Computing Curriculum Model and its Implementation

This paper analyzes difficulties with the introduction of object-oriented concepts in introductory computing education and then proposes a two-language, two-paradigm curriculum model that alleviates such difficulties. Our two-language, two-paradigm curriculum model begins with teaching imperative programming using Python programming language, continues with teaching object-oriented computing using Java, and concludes with teaching object-oriented data structures with Java.

On the Study of Automatic NC-Code Programming Based on DXF Files

In this paper, a method of automatic NC code programming is studied. The data structure used to store graph information is the base of automatic programming system. By utilizing the object-oriented tree data structure proposed in the paper, the disadvantages of the method caused by using simple data structures can be overcome. In processing information, the judgment of topological relationship between two outlines is very important. The Loop Extremum Method is easy, convenient and with no limitations. The system adds plenty of technological parameters, provides multiple machining patterns. In the end, an example is given to test and verify the system`s functions.

The Intelligent Question Band Management System of Engineering Graphics for Multiobject

By utilizing object-oriented technology and unified data structure, the intelligent question band management system of engineering graphics for multiobject (IQBMS-EG) has been implemented. In order to ensure system security and realize resource sharing, the authorities of different objects are given properly. In the IQBMS-EG, besides the conventional modules of users management and the test question management, the test paper management module has been designed to group, analyze and typeset test papers. Of all, grouping test papers can be automatic or non-automatic, and automatic grouping test papers is achieved by using genetic algorithm, which makes procedure more objective, efficient and intelligent. For students, a users record management module is designed specially, which can realize special evaluation and comprehensive evaluation. In the paper, the design idea and mainly realize technology have been presented.

Meaning and Links

This article presents some fundamental ideas about representing knowledge and dealing with meaning in computer representations. I will describe the issues as I currently understand them and describe how they came about, how they fit together, what problems they solve, and some of the things that the resulting framework can do. The ideas apply not just to graph-structured node-and-link representations, sometimes called semantic networks, but also to representations referred to variously as frames with slots, entities with relationships, objects with attributes, tables with columns, and records with fields and to the classes and variables of object-oriented data structures. I will start by describing some background experiences and thoughts that preceded the writing of my 1975 paper, What's in a Link, which introduced many of these issues. After that, I will present some of the key ideas from that paper with a discussion of how some of those ideas have matured since then. Finally, I will describe some practical applications of these ideas in the context of knowledge access and information retrieval and will conclude with some thoughts about where I think we can go from here.

Integrating multiple information representations in a single CAD/CAM/CAE environment

The number of Computer-Aided Design, Computer-Aided Manufacturing, and Computer-Aided Engineering (CAD/CAM/CAE) programs and their capabilities has risen greatly in recent times. The programming efforts continue to be significant as each application developer strives to integrate more functionality. This paper describes a study on module integration in CAD/CAM/CAE software that considers how software can be structured to enable and ease the integration. This paper deals specifically with the issue of which object-oriented data structure is best for integration to minimize code execution times, memory usage, and programming effort. That is, we are interested in identifying the ideal base class for information objects. The study compares scene-graph and Information Model representations, compares two object referencing approaches (by path and direct object references), four modes of information interpretation, and three integration schemes. The study concludes that the ideal system combines scene-graph and Information Model approaches into one new flexible approach in which the information object base class contains a generically traversable array holding schema and user attributes. In general, objects should be referenced by a path from the hierarchy root object. Object information should be interpreted into an application context by a third object or interface. New information objects from a secondary representation should be embedded into the information hierarchy of the primary representation when they do not need to reference other objects, otherwise multiple inheritance or Component Object Modeling should be used to combine the corresponding objects from multiple representations into a single new object.

Towards object-oriented finite element pre-processors exploiting modern computer technology

This paper presents efficient pre-processing algorithms for the finite element method. While finite element pre-processing is well known, it appears to have been stuck with algorithms that work, and we have stopped seeking superior methods using new programming paradigms. To demonstrate the advantage of rewriting our code, we present new software that can handle any general 2D geometrical shape and uses object-oriented data structures to achieve superior performance. The user is allowed to construct the object freely using mouse and keyboard almost with no restriction. The software identifies invalid input such as overlapping polygons and handles them appropriately. Object-oriented data structures are used to represent the problem. Data are available to the user in the XML format. Special techniques are used to handle errors due to floating operations. The software is developed in Visual C++ and has been used for many finite element analysis problems successfully.

Implementation of a Sketch Based Approach to Conceptual Aircraft Design Synthesis and Modeling

In the context of applying computer aided design tools to aircraft conceptual design, a sketch based approach is proposed to help designers turn their original concepts into complex numerical models that are usable for further analysis and optimization. This approach emphasizes the integration of general configuration and the layout of such components as engines, payloads, fuel tanks and landing gears, and the representation of a design scheme as uniform plane sketches and three dimensional models. This paper presents the measures adopted to implement the approach in a prototype system, including the object-oriented data structure, friendly graphical user interfaces and basic features of relevant modules. Several examples generated in the prototype and applications of the results are finally outlined to illustrate the effectiveness of the approach.

Data structures in Java for matrix computations

AbstractIn this paper we show how to utilize Java's native arrays for matrix computations. The disadvantages of Java arrays used as a 2D array for dense matrix computation are discussed and ways to improve the performance are examined. We show how to create efficient dynamic data structures for sparse matrix computations using Java's native arrays. This data structure is unique for Java and shown to be more dynamic and efficient than the traditional storage schemes for large sparse matrices. Numerical testing indicates that this new data structure, called Java Sparse Array, is competitive with the traditional Compressed Row Storage scheme on matrix computation routines. Java gives increased flexibility without losing efficiency. Compared with other object‐oriented data structures Java Sparse Array is shown to have the same flexibility. Copyright © 2004 John Wiley & Sons, Ltd.

Urban 3D GIS From LiDAR and digital aerial images

This paper presents a method, which integrates image knowledge and Light Detection And Ranging (LiDAR) point cloud data for urban digital terrain model (DTM) and digital building model (DBM) generation. The DBM is an Object-Oriented data structure, in which each building is considered as a building object, i.e., an entity of the building class. The attributes of each building include roof types, polygons of the roof surfaces, height, parameters describing the roof surfaces, and the LiDAR point array within the roof surfaces. Each polygon represents a roof surface of building. This type of data structure is flexible for adding other building attributes in future, such as texture information and wall information. Using image knowledge extracted, we developed a new method of interpolating LiDAR raw data into grid digital surface model (DSM) with considering the steep discontinuities of buildings. In this interpolation method, the LiDAR data points, which are located in the polygon of roof surfaces, first are determined, and then interpolation via planar equation is employed for grid DSM generation. The basic steps of our research are: (1) edge detection by digital image processing algorithms; (2) complete extraction of the building roof edges by digital image processing and human–computer interactive operation; (3) establishment of DBM; (4) generation of DTM by removing surface objects. Finally, we implement the above functions by MS VC++ programming. The outcome of urban 3D DSM, DTM and DBM is exported into urban database for urban 3D GIS.

MmLibPython toolkit for manipulating annotated structural models of biological macromolecules

ThePython Macromolecular Library(mmLib) is a software toolkit and library of routines for the analysis and manipulation of macromolecular structural models, implemented in the Python programming language. It is accessedviaa layered object-oriented application programming interface, and provides a range of useful software components for parsing mmCIF, PDB and MTZ files, a library of atomic elements and monomers, an object-oriented data structure describing biological macromolecules, and an OpenGL molecular viewer. The mmLib data model is designed to provide easy access to the various levels of detail needed to implement high-level application programs for macromolecular crystallography, NMR, modeling and visualization. We describe here the establishment ofmmLibas a collaborative open-source code base, and the use of mmLib to implement several simple illustrative application programs.