In this paper we present a method and a tool for modelling a teletraining session in heterogenous, distributed open environments. We propose a mathematical notion for the training process. Therefore we divide a whole ...
详细信息
In this paper we present a method and a tool for modelling a teletraining session in heterogenous, distributed open environments. We propose a mathematical notion for the training process. Therefore we divide a whole training session into presentation units, define some relations on these units and develop a controller for running the session. Units consist of multimedia objects, such as text, graphics, video and audio, which have to be displayed with time and space synchronisation and coordination. In a related project at the department of softwareengineering at the Upper Austria Polytechnic University a tool for modelling and running such teletraining sessions was developed. It is based on the herein defined formalism and compiles well defined unit models into JAVAT/sup TM/ code, which can be executed by usual WEB-Browsers.
We describe the application of model checking tools to analyze a real-time software challenge in the design of Lucent Technologies' 5ESS telephone switching system. We use two tools: COSPAN for checking real-time ...
详细信息
ISBN:
(纸本)0897919149
We describe the application of model checking tools to analyze a real-time software challenge in the design of Lucent Technologies' 5ESS telephone switching system. We use two tools: COSPAN for checking real-time properties, and TPWB for checking probabilistic specifications. We report on the feedback given by the tools, and based on our experience, discuss the advantages and the limitations of the approach used.
Although several access control policies can be devised for controlling access to information, all existing authorization models, and the corresponding enforcement mechanisms, are based on a specific policy (usually t...
ISBN:
(纸本)9780897919111
Although several access control policies can be devised for controlling access to information, all existing authorization models, and the corresponding enforcement mechanisms, are based on a specific policy (usually the closed policy). As a consequence, although different policy choices are possible in theory, in practice only a specific policy can be actually applied within a given system. However, protection requirements within a system can vary dramatically, and no single policy may simultaneously satisfy them *** this paper we present a flexible authorization manager (FAM) that can enforce multiple access control policies within a single, unified system. FAM is based on a language through which users can specify authorizations and access control policies to be applied in controlling execution of specific actions on given objects. We formally define the language and properties required to hold on the security specifications and prove that this language can express all security specifications. Furthermore, we show that all programs expressed in this language (called FAM/CAM-programs) are also guaranteed to be consistent (i.e., no conflicting access decisions occur) and CAM-programs are complete (i.e., every access is either authorized or denied). We then illustrate how several well-known protection policies proposed in the literature can be expressed in the FAM/CAM language and how users can customize the access control by specifying their own policies. The result is an access control mechanism which is flexible, since different access control policies can all coexist in the same data system, and extensible, since it can be augmented with any new policy a specific application or user may require.
In our paper, "An analytical model for designing memory hierarchies" (see ibid., vol. 45, no. 10, p. 180-1, 194 (1996)), we made the following statement: "Failing to apply a specific model of workload l...
详细信息
In our paper, "An analytical model for designing memory hierarchies" (see ibid., vol. 45, no. 10, p. 180-1, 194 (1996)), we made the following statement: "Failing to apply a specific model of workload locality makes it impossible to provide an easily used, closed-form solution for the optimal cache configuration, and so the results from these papers have contained dependencies on the cache configuration-the number of levels, or the sizes and hit rates of the levels." Our description did not accurately reflect the contents of the paper by J.E. MacDonald and K.L. Sigworth (1975), and we regret any false impressions caused by the inaccuracy.
This paper targets engineers and practitioners who want a simple procedure to compute the mean performance measures of the Batch Markovian Arrival process (BMAP/G/1) queueing system when the parameter matrices order i...
详细信息
As a very promising new data model, constraint database is attracting a growing interest recently. For better applications, we need to study its design theory. But to the best of our knowledge, no papers about the des...
Real time logic (RTL) was introduced as a formalism for reasoning about the relative and absolute timing properties of computational tasks of discrete real-time systems. Extended real time logic (ERTL) is a formalism ...
详细信息
Extended Real Time Logic (ERTL) is proposed for the modelling and analysis of hybrid systems, taking as a basis Real Time Logic (RTL). RTL is a first order logic with uninterpreted predicates which relate events of a ...
详细信息
暂无评论