Vectorization path planning for autonomous mobile agent in unknown environment

This paper presents a novel real-time path planning algorithm, called InsertBug, for an autonomous mobile agent in completely unknown environment. By using the algorithm, all the planned paths are described and stored by vectors. The algorithm combines range sensor data with safety radius to determine the blocking obstacles and calculate the shortest path by choosing the intermediate points. When there is obstacle blocking the current path, the intermediate points will be calculated, and the planned path will be regenerated by inserting the intermediate points. The local optimum avoidance strategy is also considered in this algorithm by specifying a fixed direction. The agent will return to the optimal direction after running out of the local optimum. Different simulation parameters are taken to show the advantages of this algorithm. Moreover, the performance of this algorithm has also been evaluated by comparing with another usual method via simulations. The results show that the safety performance and time requirements of this algorithm are significant superior to the algorithm contrasted with.     

A web-based distributed problem-solving environment for engineering applications

In this study, a prototype of web-based distributed problem-solving environment (W-DPSE) is presented to facilitate computer aided engineering (CAE) technologies. This system provides an effective approach to distributed modeling and simulation, and in addition, to support networked collaboration such that scientists around the world could interactively, visually and experimentally explore their daily design work through the proposed system. The W-DPSE system is constructed as a three-tiered architecture, consisting of three major layers: a web client presentation interface (WCPI), computing solver servers (CSS), and a system management server (SMS). All the components within this architecture are implemented with an object-oriented approach—Java while transparent communication across these three layers is attained through the remote method invocation (RMI) technology. To generalize the applicability of the system so as to accommodate interdisciplinary and diversified applications, a novel and efficient interface is developed for wrapping legacy computation codes, including C and FORTRAN etc., as a Java component. Note that in the interface, the communication mechanisms between Java objects and legacy codes are implemented by way of java native interface (JNI) and Unix inter-process communication (IPC) provided by OS. At last, the applicability of the W-DPSE system is extensively confirmed through the practices of two engineering applications: topology optimization of structures and pollutant transport simulations of coastal waters.     

An integrated environment for requirements engineering

An integrated environment for requirements engineering that supports participatory development activities is described. The environment helps ensure quality by supporting and encouraging group participation and interaction. The computer-supported cooperative-work environment supports the development and analysis of system-and-software-level requirements for large, complex applications. It encompasses and coordinates all aspects of requirements development, from conceptual inspiration, through planning, to specific project details. Case studies of groups using this environment show it can support requirements engineering for groups of users determining system-level requirements for large, complex systems     

An intelligent database for engineering applications

Many engineering applications need to response to unpredictable events in a timely manner. Active database systems provide an event-driven rule processing capability to meet this requirement. In this paper, we present an intelligent database which integrates an object-oriented database (OODB) with an expert system, CLIPS. The paper describes the design and implementation of the rule manager of this intelligent database. In the rule manager, event-condition-action (ECA) rules are represented as first class objects of the OODB. A rule definition language (RDL) has been developed to manipulate ECA rules in a declarative way. A graphical user interface (GUI) also supplies a template to interactively define, delete, update and check ECA rules. Detection of time events, method events, absolute events and composite events is supported by the rule manager. The CLIPS inference engine is used to control condition evaluation and action execution after an ECA rule is triggered. Finally, a typical workflow application is used to illustrate the functionality of the system.     

Software environment for implementing engineering applications on MIMD computers

In this paper the concept for a software environment for developing engineering application systems for multiprocessor hardware (MIMD) is presented. The philosophy employed is to solve the largest problems possible in a reasonable amount of time, rather than solve existing problems faster. In the proposed environment most of the problems concerning parallel computation and handling of large distributed data spaces are hidden from the application program developer, thereby facilitating the development of large-scale software applications. Applications developed under the environment can be executed on a variety of MIMD hardware; it protects the application software from the effects of a rapidly changing MIMD hardware technology.     

An environment for prototyping distributed applications

Designing a distributed application is an extremely complex task. Proper facilities for prototyping distributed applications can be useful in evaluating a design, and also in understanding the effect of different parameters on the performance of an application. We describe a language for prototyping distributed applications, that supports different communication primitives with specified delay, and provides primitives to aid debugging and evaluation. Our environment for executing distributed programs supports heterogeneous computation in which processes can execute on different hardware. Different source languages can be used for coding different modules of the processes. The system has a centralized control and monitoring facility which is based on the Suntools window system.     

External environment of an autonomous manufacturing agent: dynamics and representation

A formal representation of an agent's external environment is proposed, that can be used in information flow analysis. An autoregressive process of second order is applied as the mathematical tool. The dependency X(t) = f[X[0), X(1)] is derived and the characteristic features of the dynamics of the external environment are discussed. The proposed formal representation increases the set of tools for modelling and simulation of autonomous functioning manufacturing agents. It allows for the agent rigorous information input definition and assists systems analysts in the evaluation of an information structure using different attributes of the external environment.     

An interrogative visualization environment for large-scale engineering simulations

An interrogative visualization environment is described for the interactive display and querying of large datasets. The environment combines a web-based intelligent agent facility with a visualization engine. The intelligent agent facility (IAF) incorporates a rule-based expert system for natural-language understanding, voice and text input facilities, a hierarchical clickable command list, an interface for multimodal devices such as menu-based wireless handheld devices and gesture recognition devices, and human-like avatars acting as virtual assistants. The IAF interacts with, and controls, the visualization engine through a TCP/IP network socket interface. The environment enables multiple users using a variety of interaction modes and devices to effectively browse through large amounts of data, focus on and query interesting features, and more easily comprehend and make use of the data. Application of the environment to the visualization of engineering simulations is described.     

Language engineering techniques for the development of e-learning applications

In this paper we propose the use of language engineering techniques to improve and systematize the development of e-learning applications. E-learning specifications usually rely on domain-specific languages that describe different aspects of such final e-learning applications. This fact makes it natural to adopt well-established language engineering principles during the construction of these applications. These principles promote the specification of the structure and the runtime behavior of the domain-specific languages as the central part of the development process. This specification can be used to drive different activities: rapid prototyping, provision of authoring notations and tools, automatic model checking of properties, importation/exportation from/to standards, and deployment of running applications. This language engineering concept also promotes active collaboration between instructors (the users of the languages) and developers (the designers and implementers) throughout the development process. In this paper we describe this language-driven approach to the construction of e-learning applications and we illustrate all its aspects using a learning flow sequencing language as a case study.     

An interactive environment for scientific development

System Development Corporation is developing an interactive graphic scientific development system whose primary objective is ease of direction and use. This system provides an environment within which a scientific researcher—for example, an image processor—can design processes, investigate results, and guide experimental steps.

The SDC system is interactive and natural. The user communicates in mathematical or graphic handwritten notation; he can use standard tools or create his own. For example, the user can draw a graph and have it saved as a function, or he can create functions using mathematical notation.     

A fuzzy-logic autonomous agent applied as a supervisory controller in a simulated environment

An unsupervised learning system, implemented as an autonomous agent is presented. A simulation of a challenging path planning problem is used to illustrate the agent design and demonstrate its problem solving ability. The agent, dubbed the ORG, employs fuzzy logic and clustering techniques to efficiently represent and retrieve knowledge and uses innovative sensor modeling and attention focus to process a large number of stimuli. Simple initial fuzzy rules (instincts) are used to influence behavior and communicate intent to the agent. Self-reflection is utilized so the agent can learn from its environmental constraints and modify its own state. Speculation is utilized in the simulated environment, to produce new rules and fine-tune performance and internal parameters. The ORG is released in a simulated shallow water environment where its mission is to dynamically and continuously plan a path to effectively cover a specified region in minimal time while simultaneously learning from its environment. Several paths of the agent design are shown, and desirable emergent behavior properties of the agent design are discussed.     

An architecture for exporting environment awareness to mobilecomputing applications

In mobile computing, factors such as add-on hardware components and heterogeneous networks result in an environment of changing resource constraints. An application in such a constrained environment must adapt to these changes so that available resources are properly utilized. We propose an architecture for exporting awareness of the mobile computing environment to an application. In this architecture, a change in the environment is modeled as an asynchronous event that includes information related to the change. Events are typed and are organized as an extensible class hierarchy so that they can be handled at different levels of abstraction according to the requirement of each application. We also compare two approaches to structure an adaptive application. One addresses the problem of incorporating adaptiveness into legacy applications, while the other considers the design of an application with adaptiveness in mind     

An environment for painless MIMD system development

An environment that lets system applications be expressed as virtual machines, through which architecture-independent multiple-instruction, multiple-data stream (MIMD) programs are written, is described. The virtual machine hides the hardware configuration from the programmer so that the MIMD programming environment always appears the same, regardless of the actual hardware. The data-definition and procedural high-level languages used in the environment and the generation of object code in the environment are discussed. The runtime configuration of the system and an implemented prototype of the system are described     

Promoting the development of secure mobile agent applications

In this paper, we present a software architecture and a development environment for the implementation of applications based on secure mobile agents. Recent breakthroughs in mobile agent security have unblocked this technology, but there is still one important issue to overcome: the complexity of programming applications using these security solutions. Our proposal aims to facilitate and speed up the process of implementing cryptographic protocols, and to allow the reuse of these protocols for the development of secure mobile agents. As a result, the proposed architecture and development environment promote the use of mobile agent technology for the implementation of secure distributed applications.     

An environment for reusing ontologies within a knowledge engineering approach

Domain models can be constructed more easily and made more robust by reusing ontologies in a well-defined way. In this paper the KARO approach is introduced which provides various means of retrieving and adapting components of an ontology as part of a domain model construction process. KARO is based on the knowledge-processing component LILOG-KR provided by the LILOG text-understanding system. Above all, the notion of classification is applied for the retrieval of relevant categories. The upper structure of LILOG-KB serves as an exemplary ontology. By integrating KARO into the Model-based and Incremental Knowledge Engineering Environment (MIKE) the reuse of a predefined ontology can be integrated into the development process of expert systems in a systematic way.     

SUT-DAM: An integrated software environment for multi-disciplinary geotechnical engineering

As computer simulation increasingly supports engineering design, the requirement for a computer software environment providing an integration platform for computational engineering software increases. A key component of an integrated environment is the use of computational engineering to assist and support solutions for complex design. In the present paper, an integrated software environment is demonstrated for multi-disciplinary computational modeling of structural and geotechnical problems. The SUT-DAM is designed in both popularity and functionality with the development of user-friendly pre- and post-processing software. Pre-processing software is used to create the model, generate an appropriate finite element grid, apply the appropriate boundary conditions, and view the total model. Post-processing provides visualization of the computed results. In SUT-DAM, a numerical model is developed based on a Lagrangian finite element formulation for large deformation dynamic analysis of saturated and unsaturated soils. An adaptive FEM strategy is used into the large displacement finite element formulation by employing an error estimator, adaptive mesh refinement, and data transfer operator. This consists in defining new appropriate finite element mesh within the updated, deformed geometry and interpolating (mapping) the pertinent variables from one mesh to another in order to continue the analysis. The SUT-DAM supports different yield criteria, including classical and advanced constitutive models, such as the Pastor–Zienkiewicz and cap plasticity models. The paper presents details of the environment and includes several examples of the integration of application software.     

A software engineering approach for the development of heterogeneous robotic applications

One of the most evident characteristics of robotic applications is heterogeneity: large robotic projects involve many different researchers with very different programming needs and areas of research, using a variety of hardware and software that must be integrated efficiently (i.e.: with a low development cost) to construct applications that satisfy not only classic robotic requirements (fault-tolerance, real-time specifications, intensive access to hardware, etc.) but also software engineering aspects (reusability, maintainability, etc.). Most existing solutions to this problem either do not deal with such heterogeneity or do not cover specific robotic needs. In this paper we propose a framework for the integration of heterogeneous robotic software through a software engineering approach: the BABEL development system, which is aimed to cover the main phases of the application lifecycle (design, implementation, testing, and maintainance) when unavoidable heterogeneity conditions are present. The capabilities of our system are shown by its support for designing and implementing diverse real robotic applications that use several programming languages (C, C++, JAVA), execution platforms (RT-operating systems, MS-Windows, no operating system at all), communication middleware (CORBA, TCP/IP, USB), and also a variety of hardware components (Personal Computers, microcontrollers, and a wide diversity of sensor and actuator devices in mobile robots and manipulator arms).