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Proceedings. EUROMICRO 91 Workshop on Real-Time Systems

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• Proceedings. EUROMICRO '91. Workshop on Real-Time Systems

Publication Year: 1991
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• Fastchart-a fast time deterministic CPU and hardware based real-time-kernel

Publication Year: 1991, Page(s):36 - 40
Cited by:  Papers (24)  |  Patents (5)
| | PDF (296 KB)

The designer of hard realtime systems requires deterministic behaviour of the system. Today there are problems because of the hardware and the real-time kernel. So one gets only statistic statements regarding timing. The article describes a new hardware structure that is deterministic, fast and includes a real-time kernel in hardware. But this structure is limited to small real-time systems View full abstract»

• Hard real-time prototyping of SA/RT specifications

Publication Year: 1991, Page(s):80 - 87
Cited by:  Papers (3)
| | PDF (640 KB)

Preliminary results with an experimental prototyping toolset are reported. The Espex toolset is designed for graphics-based animation and real-time execution of Ward & Mellor Structured Analysis for Real-Time Systems (SA/RT) specifications. The computational model underlying the toolset is based on mapping SA/RT modeling elements to high level Petri nets. For execution of these SA/RT models a ... View full abstract»

• Real-time action

Publication Year: 1991, Page(s):174 - 182
| | PDF (516 KB)

The behavior of a real-time system depends on the scheduler used. The order in which tasks are executed depends on its characteristics such as ready time, deadline etc. The authors describe a language in which the readiness and deadlines can be specified. A scheduling policy using the task characteristics can be defined. To study the effect of schedulers on a system a notation should allow for the... View full abstract»

Publication Year: 1991, Page(s):100 - 105
Cited by:  Papers (2)
| | PDF (484 KB)

Sporadic tasks in hard-real-time systems, as defined by Mok (1983, 1988, 1989), are characterized by triples (e,d,p), 1⩽e⩽d, e⩽p. Two successive requests by the same task will be separated by at least p time units, and the task must be scheduled e time units within d time units of a request. A scheduling algorithm is said to be static if it does not depend on the sequence of requests; ... View full abstract»

• Remote procedure call protocols for real-time systems

Publication Year: 1991, Page(s):216 - 223
Cited by:  Papers (2)  |  Patents (2)
| | PDF (560 KB)

Like all real-time services, the correctness of a real-time remote procedure call depends on the processing time of the calling algorithm, the traffic on the network and eventual failures of the communication network. If the deadline of an RPC cannot be met due to these problems, the result produced by the server will be of little or no use. The authors investigate three different protocols for re... View full abstract»

• Can the advantages of RISC be utilized in real time systems?

Publication Year: 1991, Page(s):30 - 35
Cited by:  Papers (1)
| | PDF (324 KB)

Within the last few years a lot of improvements have been made for processor architectures. Average and peak performance are increasing continuously. RISC, caching, pipelining and similar features have become indispensable to many systems. In critical real time systems, however, peak and average values are of minor interest. Because strict deadlines have to be met, only those values may be conside... View full abstract»

• An operating environment for control systems on transputer networks

Publication Year: 1991, Page(s):202 - 206
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The article describes an operating environment for control systems. The environment contains the basic layers of a distributed operating system. The design of this operating environment is based on the requirements demanded by controllers which can be found in complex control systems. Due to the nature of real-time control systems, special attention has to be payed to an efficient implementation o... View full abstract»

• A graphical tool for specification of reactive systems

Publication Year: 1991, Page(s):12 - 19
Cited by:  Papers (8)
| | PDF (704 KB)

A prototype of a simulation tool with graphical visualization and animation facilities has been implemented for the DisCo specification language. The paper describes the basic ideas behind it, with emphasis on the visualization and animation facilities. The DisCo language is designed so that formal reasoning can be used to ensure critical properties of the specification. Simulation with animation ... View full abstract»

• Dynamic planning based control of autonomous machine

Publication Year: 1991, Page(s):120 - 126
Cited by:  Papers (4)
| | PDF (436 KB)

Demand for more intelligent machines will increase in the future. One field of application will be environments dangerous for human workers. This requires intelligent machines capable of autonomously operating in unstructured environments, such as mines and construction sites. Problems related to control of autonomous machines are addressed with dynamic planning based control. The heart of the con... View full abstract»

• KSE: a real-time expert system to diagnose nuclear power plant failures

Publication Year: 1991, Page(s):70 - 76
| | PDF (308 KB)

KSE is an expert system developed as an operator aid at EDF, that monitors all aspects of the electric power supply in a 900 MW PWR nuclear power plant (Bugey unit 2). KSE is mainly used as a continuous and real-time aid for diagnosing electrically induced failures and as a non real-time aid. Its architecture is based on a two-level design/application structure. The GENSIA I and GENSIA II inferenc... View full abstract»

• Reactions: an activation scheme specification language

Publication Year: 1991, Page(s):164 - 173
| | PDF (520 KB)

It is widely recognized that the special properties characterizing a reactive system especially affect its activation requirements. Therefore, the authors propose a specification language, called Reactions, specifically designed to express the activation scheme of a reactive system. The language is of a declarative form and associated with a formal semantics providing for its practical use as a pr... View full abstract»

• Allocating SMART cache segments for schedulability

Publication Year: 1991, Page(s):41 - 50
Cited by:  Papers (5)  |  Patents (4)
| | PDF (820 KB)

Since they were first introduced in the IBM 360/85 in 1969, cache designs have been optimized for average case performance, which has opened a wide gap between average case performance and the worst case performance that is critical to real-time computing community. The SMART (Strategic Memory Allocation for Real-Time) cache design narrows this gap. This paper focuses on an analytical approach to ... View full abstract»

• Embedding time granularity in logical specifications of real-time systems

Publication Year: 1991, Page(s):88 - 97
Cited by:  Papers (1)
| | PDF (712 KB)

The paper extends the TRIO logical specification formalism with the notion of time granularity. Such an extension provides the specifier with the ability of dealing with different time granularities within a single specification. It allows one to maintain the description of the dynamics of processes that evolve according to different time constants as separate as possible. It also makes it possibl... View full abstract»

• The Space Shuttle launch computer control system at NASA Kennedy Space Center

Publication Year: 1991, Page(s):184 - 192
| | PDF (408 KB)

This paper illustrates how a complex application, the data acquisition and Space Shuttle Launch Control System at NASA Kennedy Space Center, which requires both intensive communications and high processing power, can be mapped into an advanced open system architecture. This is achieved by employing a symmetric, tightly-coupled multiprocessor system which includes a high bandwidth common memory bus... View full abstract»

• Scheduling time constrained messages on miniMAP

Publication Year: 1991, Page(s):106 - 110
Cited by:  Papers (1)
| | PDF (364 KB)

The existing OSI standards, in their present form, cannot satisfy the requirements imposed by time-critical applications. The solution being sought is for a middle tier network (MiniMAP), between the full seven layer network (MAP) and the Fieldbus type networks, which will guarantee completion of critical actions within the specified time window. The paper presents a performance analysis, based on... View full abstract»

• Distributed time-management in transputer networks

Publication Year: 1991, Page(s):224 - 230
Cited by:  Papers (1)  |  Patents (1)
| | PDF (420 KB)

For real-time applications in a distributed system a common notion of time is indispensable. Clocks are used for time measurement, determination of causality, process synchronization and generating unique identifications. All this is only possible if there is a time reference of specified accuracy. Since the local clocks in a distributed system tend to drift away from each other, they need to be a... View full abstract»

• RTDB: a real-time database manager for time-critical applications

Publication Year: 1991, Page(s):207 - 214
| | PDF (636 KB)

Compared with traditional databases, database systems for time-critical applications have the distinct feature that they must satisfy timing constraints associated with transactions. Transactions in real-time database systems should be scheduled considering both data consistency and timing constraints. Since a database system must operate in the context of available operating system services, an e... View full abstract»

• Real-time system validation by model checking in TRIO

Publication Year: 1991, Page(s):20 - 28
| | PDF (632 KB)

The authors discuss the importance of formal, executable specifications in supporting validation and early prototyping of real-time systems. TRIO is a first-order temporal logic language which allows the description of quantitative aspects of time like distance in time between events and length of time intervals. They summarise the language syntax and its model-theoretic semantics. Then they prese... View full abstract»

• Extracting lines, circular segments and clusters from radar pictures in real time for an autonomous mobile robot

Publication Year: 1991, Page(s):127 - 135
Cited by:  Papers (3)
| | PDF (504 KB)

Autonomous mobile systems have to convert their sensor data in real time into meaningful data structures to navigate with their help through their environment. The authors show how to extract a description of the environment from a radar picture in real time with help of a curvature function. The mobile system MOBOT III has as its environment an office like indoor environment and obstacles detecte... View full abstract»

• Real-time architecture for knowledge processing systems

Publication Year: 1991, Page(s):52 - 60
Cited by:  Papers (3)
| | PDF (680 KB)

The paper describes an architecture for knowledge processing systems which is designed to satisfy hard real-time requirements. To achieve this, the problem of knowledge processing is separated into interacting subsystems, each processing more specific knowledge. These subsystems efficiently evaluate their knowledge according to the real-time ARON-technique (alternatives regularly organized and num... View full abstract»

• On board data fusion and decision system used for obstacle detection: a network and a real time approach

Publication Year: 1991, Page(s):193 - 200
Cited by:  Papers (1)
| | PDF (452 KB)

The paper describes a system and an algorithm used for multi-sensorial data fusion. The primary goal is to meet real time constraints with perspectives of low costs products. So the authors have chosen to use binary sensors that supply a relatively low amount of data, which allows the implementation of fast algorithms in order to compute a 2-D representation of a vehicle environment on a one DSP b... View full abstract»

• A complexity control strategy for large system models

Publication Year: 1991, Page(s):2 - 9
| | PDF (512 KB)

Abstract system models organized as functional hierarchies have complexity control problems due to the distribution of functions and state variables within the model. A model organization that employs object partitioning, the embedding of cooperating concurrent state machines, and domain separation can improve complexity control characteristics View full abstract»

• A task scheduling scheme for real-time multi-robotics systems

Publication Year: 1991, Page(s):111 - 117
Cited by:  Papers (5)  |  Patents (1)
| | PDF (496 KB)

In hard real-time systems, the importance of meeting a task execution deadline is a central issue for correctness and reliability of such systems. The focus of this research is to design and implement a real-time system which utilizes a set of mobile robots that are performing individual and common critical tasks. Specifically, a scheduling scheme consists of local and global schedulers is develop... View full abstract»

• KOS: a knowledge-based operating system for real-time onboard applications of artificial intelligence

Publication Year: 1991, Page(s):138 - 144
| | PDF (500 KB)

The paper lays out the fundamental requirements for complex real-time applications. Then, it gives an overview of the KOS (Knowledge-based Operating System) real-time executive designed to meet these requirements. KOS is the first software combining modern real-time programming and artificial intelligence. Finally, the paper proposes a definition of real-time before concluding by describing the C... View full abstract»