Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824396
Chuchang Liu, M. Ozols, Marie Henderson, A. Cant
A Certificate Management System (CMS) is used to generate, distribute, store and verify certificates. It supports secure electronic communication through its functions. In a CMS, the integrity of every certificate that a security application relies upon must be verified. The certificate verification function performs the verification process and can store verified certificates in the local database for later use. Focusing on the certificate verification function, this paper presents a state-based model for CMSs and discusses certificate verification issues. A recursive approach to certificate verification is proposed, and several verification techniques, which may be employed to reduce the amount of work in the verification process, are also presented.
{"title":"Towards certificate verification in a certificate management system","authors":"Chuchang Liu, M. Ozols, Marie Henderson, A. Cant","doi":"10.1109/ACSC.2000.824396","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824396","url":null,"abstract":"A Certificate Management System (CMS) is used to generate, distribute, store and verify certificates. It supports secure electronic communication through its functions. In a CMS, the integrity of every certificate that a security application relies upon must be verified. The certificate verification function performs the verification process and can store verified certificates in the local database for later use. Focusing on the certificate verification function, this paper presents a state-based model for CMSs and discusses certificate verification issues. A recursive approach to certificate verification is proposed, and several verification techniques, which may be employed to reduce the amount of work in the verification process, are also presented.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130993308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824376
B. Bryant
A methodology is proposed for the formal development of software systems from a user's requirements specification in natural language into a complete implementation, proceeding through the steps of formal specification, and detailed design and implementation in an automated manner. Our methodology is based upon the theories of two-level grammar (TLG) and object-oriented design and takes advantage of the existence of several existing software design tools. We develop an iterative transformation process from the natural language specification into the final implementation, with a specification development environment to assist the user, as well as the designer in accomplishing this transformation. Our underlying formal specification methodology may also be used in the final development of the implementation. This methodology is a major advance in object-oriented software development and the software engineering process in general.
{"title":"Object-oriented natural language requirements specification","authors":"B. Bryant","doi":"10.1109/ACSC.2000.824376","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824376","url":null,"abstract":"A methodology is proposed for the formal development of software systems from a user's requirements specification in natural language into a complete implementation, proceeding through the steps of formal specification, and detailed design and implementation in an automated manner. Our methodology is based upon the theories of two-level grammar (TLG) and object-oriented design and takes advantage of the existence of several existing software design tools. We develop an iterative transformation process from the natural language specification into the final implementation, with a specification development environment to assist the user, as well as the designer in accomplishing this transformation. Our underlying formal specification methodology may also be used in the final development of the implementation. This methodology is a major advance in object-oriented software development and the software engineering process in general.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128243949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824402
John Michael Potter, J. Noble
Composition and aggregation are widely used in UML analysis and design models to represent part-whole structures. Neither kind of association places any restriction on how the paths may be used from outside the whole object; this can lead to a number of problems if a part object is aliased from outside. Conglomeration realises a stronger form of encapsulation than does composition. Parts of conglomerate objects are protected from external access. By imposing instance-level consistency conditions on part-whole relationships, conglomeration can make UML models easier to build, understand, and implement correctly.
{"title":"Conglomeration-realising alias protection","authors":"John Michael Potter, J. Noble","doi":"10.1109/ACSC.2000.824402","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824402","url":null,"abstract":"Composition and aggregation are widely used in UML analysis and design models to represent part-whole structures. Neither kind of association places any restriction on how the paths may be used from outside the whole object; this can lead to a number of problems if a part object is aliased from outside. Conglomeration realises a stronger form of encapsulation than does composition. Parts of conglomerate objects are protected from external access. By imposing instance-level consistency conditions on part-whole relationships, conglomeration can make UML models easier to build, understand, and implement correctly.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133469310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824383
Annegret Goold, R. Rimmer
A group of first-year university students majoring in computer science were the subjects of this research. The performances of these students in the study of information technology unit and two units of computer programming were examined against a range of factors. Although the performance in other units studied at university was directly related to performance for all three units, from unit to unit other significant determining factors varied. Learning style and problem-solving skill were important in the study of information technology; gender and secondary school performance were important in introductory programming, while dislike of programming features in both programming units. Observed factors account for between 43 and 65 per cent of examination mark and overall performance.
{"title":"Indicators of performance in first-year computing","authors":"Annegret Goold, R. Rimmer","doi":"10.1109/ACSC.2000.824383","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824383","url":null,"abstract":"A group of first-year university students majoring in computer science were the subjects of this research. The performances of these students in the study of information technology unit and two units of computer programming were examined against a range of factors. Although the performance in other units studied at university was directly related to performance for all three units, from unit to unit other significant determining factors varied. Learning style and problem-solving skill were important in the study of information technology; gender and secondary school performance were important in introductory programming, while dislike of programming features in both programming units. Observed factors account for between 43 and 65 per cent of examination mark and overall performance.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133960862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824399
L. Naish
The study of semantics of logic programs has shown strong links between the model theoretic semantics (truth and falsity of atoms in the programmer's interpretation of a program), procedural semantics (for example, SLD resolution) and fixpoint semantics (which is useful for program analysis and alternative execution mechanisms). Nearly all of this work assumes that intended interpretations are two-valued: a ground atom is true (and should succeed according to the procedural semantics) or false (and should not succeed). In reality, intended interpretations are less precise. Programmers consider that some atoms "should not occur" or are "ill-typed" or "inadmissible". Programmers don't know and don't care whether such atoms succeed. In this paper we propose a three-valued semantics for (essentially) Horn clause programs which reflects this. It is simpler and more flexible than previously proposed type schemes and more flexible than previously proposed type schemes which implicitly recognise this third truth value. It provides tools to reason about correctness of programs without the need for unnatural precision or undue restrictions on programming style. This work has been motivated by work on declarative debugging, where it has been recognised that inadmissible calls are important.
{"title":"A three-valued semantic for Horn clause programs","authors":"L. Naish","doi":"10.1109/ACSC.2000.824399","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824399","url":null,"abstract":"The study of semantics of logic programs has shown strong links between the model theoretic semantics (truth and falsity of atoms in the programmer's interpretation of a program), procedural semantics (for example, SLD resolution) and fixpoint semantics (which is useful for program analysis and alternative execution mechanisms). Nearly all of this work assumes that intended interpretations are two-valued: a ground atom is true (and should succeed according to the procedural semantics) or false (and should not succeed). In reality, intended interpretations are less precise. Programmers consider that some atoms \"should not occur\" or are \"ill-typed\" or \"inadmissible\". Programmers don't know and don't care whether such atoms succeed. In this paper we propose a three-valued semantics for (essentially) Horn clause programs which reflects this. It is simpler and more flexible than previously proposed type schemes and more flexible than previously proposed type schemes which implicitly recognise this third truth value. It provides tools to reason about correctness of programs without the need for unnatural precision or undue restrictions on programming style. This work has been motivated by work on declarative debugging, where it has been recognised that inadmissible calls are important.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132646565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824378
Richard Cole
Concept lattices represent a conceptual hierarchy inherent in a data set. A labelled line diagram for such a lattice represents this information diagramatically. A diagram for a concept lattice may be algebraically generated by a set of vectors assigned to elements of the lattice. Such a diagram is called an additive line diagram, and is considered useful because it makes apparent the inherent structure of the lattice. This paper reports on experience with two approaches to automated concept lattice layout. (i) using generic algorithms optimising over a finite discrete space of diagrams, and (ii) force directed placement optimising over a continuous rational space. The layout of concept lattices is of relevance to the layout of lattices in general since any lattice can be represented simply by a concept lattice.
{"title":"Automated layout of concept lattices using force directed placement and genetic algorithms","authors":"Richard Cole","doi":"10.1109/ACSC.2000.824378","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824378","url":null,"abstract":"Concept lattices represent a conceptual hierarchy inherent in a data set. A labelled line diagram for such a lattice represents this information diagramatically. A diagram for a concept lattice may be algebraically generated by a set of vectors assigned to elements of the lattice. Such a diagram is called an additive line diagram, and is considered useful because it makes apparent the inherent structure of the lattice. This paper reports on experience with two approaches to automated concept lattice layout. (i) using generic algorithms optimising over a finite discrete space of diagrams, and (ii) force directed placement optimising over a continuous rational space. The layout of concept lattices is of relevance to the layout of lattices in general since any lattice can be represented simply by a concept lattice.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114267217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-01-31DOI: 10.1109/ACSC.2000.824375
A. L. Brown
The design and implementation of some persistent object stores rely on the availability of memory mapped files. A significant difficulty faced by this approach is that the programmer has very little control over when I/O occurs. In this paper, a mechanism for exposing the I/O activity of a memory mapped file is presented. This involves implementing a special purpose NFS server that provides a shadow paged file which can be memory mapped by a persistent object store. Some initial performance figures are presented to indicate the relative performance of this approach compared to more traditional approaches.
{"title":"Exposing memory mapped I/O using NFS","authors":"A. L. Brown","doi":"10.1109/ACSC.2000.824375","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824375","url":null,"abstract":"The design and implementation of some persistent object stores rely on the availability of memory mapped files. A significant difficulty faced by this approach is that the programmer has very little control over when I/O occurs. In this paper, a mechanism for exposing the I/O activity of a memory mapped file is presented. This involves implementing a special purpose NFS server that provides a shadow paged file which can be memory mapped by a persistent object store. Some initial performance figures are presented to indicate the relative performance of this approach compared to more traditional approaches.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"393 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120892145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ACSC.2000.824409
Zili Zhang, Chengqi Zhang
In multi-agent systems, each of the agents may have its own expertise. When they are asked to accomplish the same task, the results may be different. In such situations, we need to fuse the results to obtain a final one. We propose an information fusion approach when multiple agents are asked to collect the information for the same query from different resources. We also discuss the group decision fusion problem that several agents with similar knowledge make decisions using the same information. Both are based on ordered weighted averaging (OWA) operator.
{"title":"Result fusion in multi-agent systems based on OWA operator","authors":"Zili Zhang, Chengqi Zhang","doi":"10.1109/ACSC.2000.824409","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824409","url":null,"abstract":"In multi-agent systems, each of the agents may have its own expertise. When they are asked to accomplish the same task, the results may be different. In such situations, we need to fuse the results to obtain a final one. We propose an information fusion approach when multiple agents are asked to collect the information for the same query from different resources. We also discuss the group decision fusion problem that several agents with similar knowledge make decisions using the same information. Both are based on ordered weighted averaging (OWA) operator.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116094662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ACSC.2000.824386
J. Grundy
While component-based software engineering technologies have become popular, finding and reusing appropriate software components is often challenging. We describe a software component repository that uses a concept of component "aspects" to index and query components based on their high-level systemic characteristics, including their user interface, persistency, distribution, security and collaborative work support. Software components are queried for aspects of a system they provide or require and these are used to automatically generate a high-level indexing system. Developers and end users can formulate high-level, aspect-based queries to retrieve components providing or requiring services appropriate to their needs.
{"title":"Storage and retrieval of software components using aspects","authors":"J. Grundy","doi":"10.1109/ACSC.2000.824386","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824386","url":null,"abstract":"While component-based software engineering technologies have become popular, finding and reusing appropriate software components is often challenging. We describe a software component repository that uses a concept of component \"aspects\" to index and query components based on their high-level systemic characteristics, including their user interface, persistency, distribution, security and collaborative work support. Software components are queried for aspects of a system they provide or require and these are used to automatically generate a high-level indexing system. Developers and end users can formulate high-level, aspect-based queries to retrieve components providing or requiring services appropriate to their needs.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132556057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ACSC.2000.824379
R. Colvin, I. Hayes, P. Strooper
The logic programming refinement calculus is a method for transforming specifications to executable code, maintaining the correctness of the code with respect to its specification. In this paper we show how types can be handled in the logic programming refinement calculus. Types of variables are necessary for a complete specification of a procedure, and typing information can guide the refinement of a procedure specification to code. As an application of this framework, we show how dynamic type-checks can be formally eliminated from a sample program.
{"title":"Refining logic programs using types","authors":"R. Colvin, I. Hayes, P. Strooper","doi":"10.1109/ACSC.2000.824379","DOIUrl":"https://doi.org/10.1109/ACSC.2000.824379","url":null,"abstract":"The logic programming refinement calculus is a method for transforming specifications to executable code, maintaining the correctness of the code with respect to its specification. In this paper we show how types can be handled in the logic programming refinement calculus. Types of variables are necessary for a complete specification of a procedure, and typing information can guide the refinement of a procedure specification to code. As an application of this framework, we show how dynamic type-checks can be formally eliminated from a sample program.","PeriodicalId":304540,"journal":{"name":"Proceedings 23rd Australasian Computer Science Conference. ACSC 2000 (Cat. No.PR00518)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132069816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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