Object-oriented Techniques Research Articles

Modelling and Simulation of High Fidelity CDU for Flight Simulator Based on Object-Oriented and Hardware-in-Loop Technique

A high fidelity, reliable and extensible real-time CDU simulation system is built on the basis of self-made membrane keyboard and object-oriented simulation method in this paper to improve the visual feelings and simulation fidelity of CDU in flight management system research. Based on embedded PC104 CPU and 8255 programmable peripheral equipment interface card, the membrane keyboard hardware circuit and the keyboard code scanning program are designed. Accordingly, the confused logical problem of keystokes is solved and meanwhile, the emulation CDU keyboard is realized. And then, an extensible and reliable CDU pages system is constructed utilizing object-oriented simulation technique, inheritance and polymorphism mechanisms. Thus, the tiresome generation and management problem of pages system is tackled. Simulation experiments illustrate that routing data and performance parameters can be input and displayed realistically on the CDU system developed in this paper.

Design and implementation of particle system based on content pipeline in XNA

Particle system is one of the hot topics in the game engine.In this paper,the general principle of particle system was introduced.Aiming at processing custom content files in XNA easily,by making use of object-oriented technique and extending the behavior of content pipeline,a particle system module was developed.The definition of management interface and the relation of hierarchy of particle system modeling were given.And particle system was integrated and encapsulated.At last,a concrete application was given by making use of XNA Game Studio.

A methodology to specify three-dimensional interaction using Petri Nets

This work presents a methodology to formally model and to build three-dimensional interaction tasks in virtual environments using three different tools: Petri Nets, the Interaction Technique Decomposition taxonomy, and Object-Oriented techniques. User operations in the virtual environment are represented as Petri Net nodes; these nodes, when linked, represent the interaction process stages. In our methodology, places represent all the states an application can reach, transitions define the conditions to start an action, and tokens embody the data manipulated by the application. As a result of this modeling process we automatically generate the core of the application's source code. We also use a Petri Net execution library to run the application code. In order to facilitate the application modeling, we have adapted Dia, a well-known graphical diagram editor, to support Petri Nets creation and code generation. The integration of these approaches results in a modular application, based on Petri Nets formalism that allows for the specification of an interaction task and for the reuse of developed blocks in new virtual environment projects.

An Evaluation of Object-Oriented Image Analysis Techniques to Identify Motorized Vehicle Effects in Semi-arid to Arid Ecosystems of the American West

Human disturbance is a leading ecosystem stressor. Human-induced modifications include transportation networks, areal disturbances due to resource extraction, and recreation activities. High-resolution imagery and object-oriented classification rather than pixel-based techniques have successfully identified roads, buildings, and other anthropogenic features. Three commercial, automated feature-extraction software packages (Visual Learning Systems' Feature Analyst, ENVI Feature Extraction, and Definiens Developer) were evaluated by comparing their ability to effectively detect the disturbed surface patterns from motorized vehicle traffic. Each package achieved overall accuracies in the 70% range, demonstrating the potential to map the surface patterns. The Definiens classification was more consistent and statistically valid.

Modeling Complexity in Physically-Distributed Object-Oriented Systems

This research explores the characteristics and implementation challenges of a complex, distributed system that attaches data processing and storage capabilities to physical objects. In the context of systems based on radio frequency identification (RFID) technology, we present a model that defines the constituents of complexity in this type of system, and discuss how object-oriented techniques can mitigate the complexity. The model, extended from prior models of organizational change and systems development, defines system complexity across three dimensions: architecture, component, and infrastructure. The model explains how changes in the architectural and component knowledge of a system are engendered by the shift from a digital to a physical infrastructure, leading to what is termed a ‘radical’ change. We link the architectural and component characteristics of a physically distributed object-oriented (PDO) system to the design elements of an object-oriented system, and indicate how an object-oriented approach can mitigate the complexity of the physical system's design and overall control structure.

An object-oriented approach to assessing changes in tree cover in the Colorado Front Range 1938–1999

In the wake of numerous catastrophic wildfires, forest management policies have been implemented in recent years in the United States with the goals of reducing fire risk, including the National Fire Plan and the Healthy Forest Restoration Act. A key premise underlying these policies is that fire suppression has resulted in denser forests than were present historically that now have higher fire risk. To evaluate this premise for the northern Front Range, Colorado, we used object-oriented image analysis to compare change in tree cover delineated from historical and modern imagery. Historical photographs from 1938 and 1940 were scanned, orthorectified, and overlaid on Digital Orthoimagry Quarter Quadrangles (DOQQs) from 1999. Using an object-oriented image analysis technique, the photos were then finely segmented and classified into two classes: tree and non-tree. Trees are heterogeneous in appearance in black and white aerial photography, so we employed separate membership functions to identify four visually distinct types: ‘interior forest’, ‘isolated trees’, ‘dark forest’, and ‘edge forest’. Our classification strategy employed spatial relationships between objects in addition to spectral information, so that our classification is fairly robust to variations in illumination. Based on the classification of fine objects, we then calculated the percent tree cover within a larger set of objects for the two time periods. We estimate that average tree density across the study area increased minimally (4%) during the 60-year period, with considerable spatial variation across the landscape. The results of the analysis illustrate that, consistent with independent tree-ring evidence, the highest increase in tree density is in areas characterized by low initial density, south-facing slopes, low elevations, and ponderosa pine dominance. In contrast, the highest elevation areas dominated by mixed conifer and lodgepole pine forests revealed no significant change in tree cover. Furthermore, there is no significant difference between objects dominated by low, medium, and high departure from historical conditions, as classified in the Landfire Fire Regime Condition Class (FRCC) data product. The results of the study can help managers prioritize forest treatments aimed at restoring pre-suppression forest structure.

Modelling process platforms based on an object-oriented visual diagrammatic modelling language

Process platforms have been recognised as a promising means of dealing with product variety while achieving a near mass production efficiency. To assist practitioners to better understand, implement and use process platforms, this study addresses the underlying logic for coping with the challenges in high variety production by adopting process platforms. Accordingly, this paper proposes to model process platforms with focus on the application processes. In view of the significance of dynamic modelling and visualisation in shedding light on the logic of any processes, this study introduces a visual diagrammatic modelling language based on object-oriented (OO) techniques, named as OOVDML. With the graphical notations, uniquely shaped symbols, syntax and semantics, control mechanisms and arrangement rules, the OOVDML not only captures the logic of process platform's application but also provides a visualisation of their behaviours in a holistic view. Moreover, incorporating OO modelling allows readers to focus on their own interests. This study approaches to modelling process platform's application with respect to activities pertaining to customer order processing, engineering change control and production job planning. An industrial example of electronics products is also reported. The results of the case study not only show the suitability of the OOVDML but also shed light on the dynamic behaviours of process platforms.

Catastrophic regime shifts in coral communities exposed to physical disturbances: Simulation results from object-oriented 3-dimensional coral reef model

A 3-dimensional individual-based model, the ReefModel, was developed to simulate the dynamical structure of coral reef community using object-oriented techniques. Interactions among functional groups of reef organisms were simulated in the model. The behaviours of these organisms were described with simple mechanistic rules that were derived from their general behaviours (e.g. growing habits, competitive mechanisms, response to physical disturbance) observed in natural coral reef communities. The model was implemented to explore the effects of physical disturbance on the dynamical structure of a 3-coral community that was characterized with three functional coral groups: tabular coral, foliaceous coral and massive coral. Simulation results suggest that (i) the integration of physical disturbance and differential responses (disturbance sensitivity and growing habit) of corals plays an important role in structuring coral communities; (ii) diversity of coral communities can be maximal under intermediate level of acute physical disturbance; (iii) multimodality exists in the final states and dynamic regimes of individual coral group as well as coral community structure, which results from the influence of small random spatial events occurring during the interactions among the corals in the community, under acute and repeated physical disturbances. These results suggest that alternative stable states and catastrophic regime shifts may exist in a coral community under unstable physical environment.

Using modes of inquiry and engaging problems to link computer science and mathematics

In this paper we show how an engaging problem can be used in both a discrete mathematics course and a programming course as a way to expose students to multiple methods of inquiry and to strengthen the links between the two courses. Since students typically take Discrete Mathematics and a programming course simultaneously, this is an opportunity for them to analyze a problem from multiple perspectives during a single semester. We describe how we have accomplished this using a relatively new problem that is easily stated and has a surprising solution that defies intuition. In the programming course, students experienced a design/empirical approach to the problem by implementing simulations of various solutions and collecting experimental results. By adjusting the emphasis of the programming assignment, we show that it can fit naturally into a range of programming courses, i.e. courses on introductory programming, data structures, and object-oriented techniques. In the Discrete Mathematics course, students analyzed solutions using tools from counting, probability, and calculus. We observed that by linking the two courses using a common problem, our students were more cognizant of inquiry methods and student engagement increased.

A multi-method intercomparison approach for precipitation fields modelled by LAMs in the Alpine area: Two FORALPS case studies

Sharing knowledge and experience about NWP verification among forecasting centres, research institutions and environmental agencies in the Alpine area has been one of the main goals of the EU FORALPS project – INTERREG IIIB Alpine Space. In this framework, state-of-the-art verification techniques employed by project partners have been shared and applied to numerical simulations of selected case studies of rainfall events on the north-eastern Alpine area. In this work, a multi-method approach is presented. Simulations of two events with three limited area models (LAMs) are verified with traditional and more innovative techniques, including both traditional eyeball methods, categorical scores and skill scores, along with advanced object-oriented techniques such as the continuous rain area (CRA) analysis. Simulations of satellite observed fields (METEOSAT-7 Water Vapour channel) are also employed, to check qualitatively the impact of initialisation on the model error growth. Most importantly, it is shown how this multiplicity of perspective allows a deeper understanding of the results and facilitates their interpretation, thus suggesting that this multi-method approach should be followed in future works.

A Snort-based agent for a JADE multi-agent intrusion detection system

We describe the design of a misuse detection agent, one of the distinct agents in a multi-agent-based intrusion detection system. This system is being implemented in JADE, a well-known multi-agent platform based in Java. The agent analyses the packets in the network connections using a packet sniffer and then creates a data model based on the information obtained. This data model is the input to a rule-based inference engine agent, which uses the Rete algorithm for pattern matching and the rules of the signature-based intrusion detection system, Snort. Specifically, an implementation in Java language – the Drools-JBoss Rules – was used and a parser was implemented that converts Snort rules into Drools rules. The use of object-oriented techniques, together with design patterns, means that the agent is flexible, easily configurable and extensible.

Generating Business Process Models from Object Behavior Models

Object-oriented modeling is an established approach to document information systems. In an object model, a system is captured in terms of object types and associations, state machines and collaboration diagrams, among others. Process modeling on the other hand, provides a different approach whereby behavior is captured in terms of activities, flow dependencies, resources, etc. These two approaches have their relative advantages. Also, object models and process models lend themselves to different styles of implementation. In this paper we define a transformation from a meta-model for object behavior modeling to a meta-model for process modeling. The transformation relies on the identification of causal relations in the object model. These relations are encoded in a heuristics net from which a process model is derived and then simplified. Using this transformation, it becomes possible to apply established object-oriented techniques during system analysis and design, and to transform the resulting object models into executable process models that can be deployed in a workflow engine. The proposal has been implemented in an object modeling tool.

Spatial analysis software testing tool based on object-oriented techniques

Object-oriented (OO) programming and system design have become the scalable methodology for large-scale enterprise and technology system designs. Spatial and geographic information system (GIS)-based systems are not exempt from this trend and have widely adopted object-oriented methodology. Testing strategies for systems developed with OO technologies need to be carefully evaluated. Specific features of OO technologies such as information hiding and close tying of data structures with class structures and the natural peculiarities of the spatial data require revisiting of test strategies for spatial applications built on OO technology. This article focuses on object-oriented testing trends and the development of associated tools in the GIS industry.

The RAVE/VERTIGO vertex reconstruction toolkit and framework

A detector-independent toolkit for vertex reconstruction (RAVE1) is being developed, along with a standalone framework (VERTIGO2) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.

Object-oriented development and application of a nonlinear structural analysis framework

This paper describes the framework and application of numerical simulation software on earthquake engineering research and practice. The analysis kernel is developed at the National Center for Research on Earthquake Engineering (NCREE) and is entitled as “Platform of Inelastic Structural Analysis for 3D systems (PISA3D)”. The design of PISA3D framework adopts the Design Pattern and the Unified Process. PISA3D provides structural modeling and high computational efficiency for engineers and researchers to simulate the responses of nonlinear systems under various kinds of load effects. It includes static or cyclic loads, displacements, earthquake ground accelerations, and earthquake aftershocks. PISA3D is easy to extend and maintain due to its object-oriented nature. Advanced users can derive or compose its objects’ libraries to perform different types of structural analyses. Based on object-oriented techniques, VISA3D (Visualization of Inelastic Structural Analysis for 3D systems) has been implemented with usage of OpenGL for 3D graphics and MFC for graphical user interface (GUI). Its framework allows further extension on new input formats and new element types. VISA3D has been mainly developed as a post-processor to examine the analytical results of PISA3D through 2D/3D static or dynamic graphic approaches. It includes graphical checking of the structural model, mode shapes, deformations, extents and locations of plastic hinges, plotting of nodal velocity, acceleration, and energy distribution time histories. This paper then introduces NCREE’s recent development on the pre-processing framework GISA3D (Graphical Interface of Inelastic Structural Analysis for 3D systems). The GISA3D does not only supply features as a “post-processor”, but also fully supports operations of “model generation” via mouse motion. Users can create, remove, modify and set elements/nodes through mouse clicking, dragging and selecting. Finally, this paper illustrates the networked sub-structural pseudo dynamic tests using PISA3D as the analysis engine, and concludes with several successful applications of PISA3D/VISA3D/GISA3D on various researches and actual structural engineering projects.

Object-Oriented Software Cost Estimation Methodologies Compared

Executive Summary Most commonly available software cost estimation methodologies and tools use either source lines of code (SLOC) or function point (FP) measures as the basis for the estimate. While these methodologies and tools may suffice for software projects that use structured software development techniques, when object-oriented (OO) techniques such as use-case modeling are employed, it is more effective to use a methodology that takes advantage of the information provided by the use cases, scenarios, and more in-depth object-oriented metrics. Furthermore, as an organization becomes proficient in developing object-oriented system software, the traditional metrics of SLOC and FPs become less useful because each individual line of code becomes less likely to be like the others. Using use cases as the basis for effort estimation is a valuable addition to the tools available to a project manager, particularly for those projects where use cases are produced as part of the life-cycle process. Though use c...

No Silver Bullet: Software Engineering Reloaded

A celebratory panel took place at the 22nd International Conference on object-oriented programming, systems, languages, and applications in Montreal. The occasion was the 20th anniversary of Fred Brooks' paper bullet: essence and accidents of software engineering. Fred suggested that useful solutions must address inherent complexity observing that object-oriented techniques have come closest to achieving this goal. David described a silver as a technique that requires no training or experience to apply a bullet should find its mark without aim. Software engineering as a discipline has expanded significantly, both in terms of system complexity and the community's global extent. continues to be both an enjoyable must-read and an influential reference. People use languages without the ideas, so the object community still has much to do. It is nice to know that, when all else fails us, we have an innate decision-making tool to fall back on.

Simulating Complex Adaptive Geographic Systems: A Geographically Aware Intelligent Agent Approach

The objective of this paper is to present a spatially explicit agent-based simulation framework with a supporting software package to explore complex adaptive geographic systems. This framework is particularly suitable for modeling entities that are contextually aware, knowledge driven, and adaptive because it represents them as geographically aware intelligent agents. Fundamental advances in the explicit representation of contextual information, knowledge structures, and learning processes are needed for modeling intelligent agents situated within geographic systems. The representation of these agents requires the integration of agent-based models, machine learning, and GIS. Existing software packages for agent-based modeling, however, often provide insufficient support for this integration. The agent-based simulation package presented here is specifically designed to achieve such integration by assisting the development of agent-based models from the simulation framework. Object-oriented modeling techniques were used to implement this simulation package, which includes four modules: simulation, visualization, learning, and geoprocessing. In particular, the learning and geoprocessing modules facilitate the representation of adaptive behavior in agents within spatially explicit environments. The utility of the agent-based simulation package is illustrated using two simulation models: one of adaptive elk behavior and another of pedestrian movement. The successful design of the simulation models suggests that the modeling framework with the supporting software package is well suited to the resolution of complex adaptive geographic problems.

Verifying experiment for automated design of mechatronic systems using Bond-Graph modelling and simulation and genetic programming

All modern dynamic engineering systems can be characterised as mechatronic systems. The multi-domain nature of a mechatronic system makes it difficult to model using a single modelling technique over the whole system as varying sets of system variables are required. Bond-Graphs offer an advanced object-oriented modelling and simulation technique. They are domain independent allowing straight forward and efficient model composition, classification and analysis. Bond-Graph model of the mechatronic system can be directly simulated on a digital computer using simulation software such as 20-Sim© and Modelica© graphically or manipulated mathematically to yield state equations using a simplified set of power and energy variables. The simulation scheme can be augmented to synthesise designs for mechatronic systems using genetic programming as a tool for open-ended search. This research paper presents results of an experiment conducted to verify a unified approach developed by combining Bond-Graph modelling and simulation with genetic programming for automated mechatronic system design. A comprehensive review of various aspects of the physical modelling paradigm along with the concept and development of automated design and the methodology is also included.

A method for platform identification to support service family design

Customised services are an important source of revenue for many companies, particularly those subscribing to mass customisation where customer satisfaction is paramount. In this paper, we extend concepts from platform-based product family design to create a new method for module-based service family design. The objective in this research is to introduce a method for identifying a service platform along with variant and unique modules to create a service family by integrating object-oriented concepts, ontologies and data-mining techniques. Object-oriented concepts were used to support service analysis and representation combining ontologies. Fuzzy clustering is employed to partition service processes into subsets to identify common modules – the platform – and specific modules for the given service family. To demonstrate the proposed approach, we apply the proposed method to select a platform for a family of banking services.