Annual Review in Automatic Programming最新文献

With the advancements in multimedia and networking technologies, many distributed multimedia applications have been developed recently. These new applications rely on the underlying network support to transmit the multimedia real-time data between sites. Multimedia Transport Protocol (MMTP) is an experimental protocol designed for transmission of various multimedia data. MMTP uses multiple priority queues to support different levels of service requirements, and it discards packets from the transmission queue to reduce the network loading, and to ensure packets transmitted will meet the real-time constraint required by the data streams.

A problem with simulation of multilayer neural network on transputer array is described in this article. The decomposition and mapping on given architecture is proposed as well as a simple message passing scheme. Practical experiments with inverted pendulum plant are described including useful hints for setting neural network architecture and tuning neural networks parameters. Then neural controller is designed and criterion function is defined for given control problem. Finally the real-time aspects of the controller design are outlined.

Optical ellipsometry has been found to be a promising technique for monitoring process parameters, such as film composition and film thickness, of semiconductor wafers grown with molecular beam epitaxy. Whereas it is a straightforward task to calculate ellipsometry angles given the thickness of the film and the refractive indices of the film and substrate, it is a difficult task to invert that mathematical relationship. However, the process must be inverted if we wish to monitor film composition and film thickness.

This paper reports on the use of neural-nets for the inverse mapping. We used a Functional Link net which is very efficient in function approximation. The advantage of using the net, however, is not only its speed, but also because some other net architecture characteristics allow us to perform the task in a holistic manner. For sufficiently accurate experimental conditions, the neural-nets may be used to monitor both film material composition and film thickness.

The transition from Boolean Logic to Fuzzy Logic is shown by modifying a ladder diagram consisting of discrete variables with values of 0 and 1 to include intermediate values. Properties of membership functions are discussed as they influence the control output. The concept of compromise and output blending is shown. Important observations regarding the presence of rules are presented. The notions of “gain” and “time” are introduced, and a PID controller using Fuzzy Mechanisms is shown. In one example, the level and temperature of a tank are controlled; in another example the engine power and the turning of the wheels of an automobile are controlled as a function of the gas pedal and the steering wheel excitation.

The Statechart and Grafcet synchronous models are compared in view of their application to the control of hybrid systems. The Cruise Control case study emphasises the specific features and similarities of both methods. The simulation of the Grafcet model uses an original algorithm. Issues about the coherent management of variables in hybrid systems are raised.

An overview of some hardware-software codesign schemes will be given. In contrast to these approaches, a proposal will be made which builds on the similarity of Ada and VHDL and is strongly oriented towards immediate practical applicability. The proposal can be characterized as object-based, software-oriented, manual, hardware-software re-partitioning. The proposal is illustrated with an fictitious example from the on-board software of the EURECA spacecraft.

This paper presents a new conception for a distributed task-oriented real-time operating system comprising a compiler, an operating system kernel and communication packages. The system TOROS supplies the tools for a uniform programming of complex process control applications on heterogenous hardware including workstation, PC, programmable controller and microcontroller. The whole control task is split into a set of small modules. These modules are uniquely programmed by defining a state machine and using guarded commands. They are connected logically through calls to tasks provided by other modules. The specification of the modules is done in an hardware independent language. At compile time the modules are distributed to specified target computers. The system automatically translates each module into the particular code and realizes the communication between the modules either on the same computer or through the links.

Usually, there are two alternative approaches to program the application functions to be performed by a hard real-time system: the method of sequential programming of tasks often performed under control of a multi-tasking operating system and, on the other hand, the quasi-parallel description of application functions which are realized by means of a cyclic execution e.g. of a programmable logic control. Although being alternatives in a wide area of applications, there are always aspects of each form of programming where the solution for a specific problem is not really satisfying. Therefore we tried to make use of a combined programming of real-time applications by means of both methods which showed to offer an optimal programming toolset. This paper presents specific characteristics of the two methods, aspects of the combination and examples coming from a new robot programming language which is designed this way.

In this paper we describe a new Architecture for hard Real-Time Environments (ARTIE). The architecture is essentially an asymmetrical two-processor system. It consists of a task processor for the application programs and the operating system's shell functions, and of a reliable co-processor for the real-time operating system kernel. We have formally derived the specifications for the kernel programs and proved that the programs behave according to the specifications. The practical performance of the system is evaluated by simulating a typical real-time application on a workstation.