93,391 research outputs found
Precise service level agreements
SLAng is an XML language for defining service level agreements, the part of a contract between the client and provider of an Internet service that describes the quality attributes that the service is required to possess. We define the semantics of SLAng precisely by modelling the syntax of the language in UML, then embedding the language model in an environmental model that describes the structure and behaviour of services. The presence of SLAng elements imposes behavioural constraints on service elements, and the precise definition of these constraints using OCL constitutes the semantic description of the language. We use the semantics to define a notion of SLA compatibility, and an extension to UML that enables the modelling of service situations as a precursor to analysis, implementation and provisioning activities
Formal Verification of Real-Time Function Blocks Using PVS
A critical step towards certifying safety-critical systems is to check their
conformance to hard real-time requirements. A promising way to achieve this is
by building the systems from pre-verified components and verifying their
correctness in a compositional manner. We previously reported a formal approach
to verifying function blocks (FBs) using tabular expressions and the PVS proof
assistant. By applying our approach to the IEC 61131-3 standard of Programmable
Logic Controllers (PLCs), we constructed a repository of precise specification
and reusable (proven) theorems of feasibility and correctness for FBs. However,
we previously did not apply our approach to verify FBs against timing
requirements, since IEC 61131-3 does not define composite FBs built from
timers. In this paper, based on our experience in the nuclear domain, we
conduct two realistic case studies, consisting of the software requirements and
the proposed FB implementations for two subsystems of an industrial control
system. The implementations are built from IEC 61131-3 FBs, including the
on-delay timer. We find issues during the verification process and suggest
solutions.Comment: In Proceedings ESSS 2015, arXiv:1506.0325
Autonomous Agents for Business Process Management
Traditional approaches to managing business processes are often inadequate for large-scale organisation-wide, dynamic settings. However, since Internet and Intranet technologies have become widespread, an increasing number of business processes exhibit these properties. Therefore, a new approach is needed. To this end, we describe the motivation, conceptualization, design, and implementation of a novel agent-based business process management system. The key advance of our system is that responsibility for enacting various components of the business process is delegated to a number of autonomous problem solving agents. To enact their role, these agents typically interact and negotiate with other agents in order to coordinate their actions and to buy in the services they require. This approach leads to a system that is significantly more agile and robust than its traditional counterparts. To help demonstrate these benefits, a companion paper describes the application of our system to a real-world problem faced by British Telecom
THE ENGLISH DEPARTMENT STUDENTS’ USE OF JAVANESE LANGUAGE
This paper concerns the use of Javanese language by English department students of Diponegoro
University, Semarang, Indonesia. The students selected as the subjects of research are those of the second
(2
nd
) and fourth (4
th
) semesters whose both parents are Javanese. In total, there were sixty-two (62)
students participating in the research. The students were given questionnaires and discourse completion
tasks to fill in; the questionnaires were used to elicit data regarding the students’ choice of codes in the
family or home domain, and the discourse completion tasks (DCT-s) were used as a means to double
check their answers in the questionnaires. The highest statistics of Javanese usage in the family domain
is between the respondents and their older siblings because within this context they can use ngoko, the
style of Javanese they master the most, whereas in interactions other than that with their siblings, the
students must use krama, madya or ngoko alus styles, depending upon the participants’ ages, social status
and distance. Most of the students, as is shown in the DCT-s, are at best in the ngoko style
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