In this paper, the problem of optimal scheduling of independent tasks on heterogeneous computing systems is considered. Optimal scheduling algorithms which produce preemptive schedules with minimal completion times and non-preemptive schedules with minimal mean flow times are described. A bound on mean flow times also provides us with information concerning the relative merit of different multiprocessor systems.
{"title":"Optimal scheduling of independent tasks on heterogeneous computing systems","authors":"J. Liu, Aihua Yang","doi":"10.1145/800182.810377","DOIUrl":"https://doi.org/10.1145/800182.810377","url":null,"abstract":"In this paper, the problem of optimal scheduling of independent tasks on heterogeneous computing systems is considered. Optimal scheduling algorithms which produce preemptive schedules with minimal completion times and non-preemptive schedules with minimal mean flow times are described. A bound on mean flow times also provides us with information concerning the relative merit of different multiprocessor systems.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"1 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":"128957462","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}
Each year Chemical Abstracts Service (CAS) publishes over 62,000 chemical structure diagrams in its various publications. Until recently, each of these diagrams was drawn by a draftsman, photographed and stripped into the final page copy, interspersed with computer-composed textual information. This paper describes a system for inputting chemical structure diagrams from a CRT terminal, storing the graphical data on a magnetic disk, and subsequently outputting the data to a computer-controlled composition system. A description of the graphical data structure used to store the structure diagrams is given first, followed by a description of the input and output systems. Finally, some comments and conclusions concerning the production use of this system are presented.
{"title":"A computer-based system for input, storage, and photocomposition of graphical data","authors":"Nick A. Farmer, Joseph C. Schehr","doi":"10.1145/1408800.1408853","DOIUrl":"https://doi.org/10.1145/1408800.1408853","url":null,"abstract":"Each year Chemical Abstracts Service (CAS) publishes over 62,000 chemical structure diagrams in its various publications. Until recently, each of these diagrams was drawn by a draftsman, photographed and stripped into the final page copy, interspersed with computer-composed textual information. This paper describes a system for inputting chemical structure diagrams from a CRT terminal, storing the graphical data on a magnetic disk, and subsequently outputting the data to a computer-controlled composition system. A description of the graphical data structure used to store the structure diagrams is given first, followed by a description of the input and output systems. Finally, some comments and conclusions concerning the production use of this system are presented.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"290 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":"127596081","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}
The extremely complex nature of the electroencephalogram (EEG), and the subtle, nonquantified methods of pattern recognition used by human interpreters have made EEG analysis resistant to automation. Attempts at pattern recognition using multivariate classification procedures have not produced generalizable results due to the inadequate degree and quality of feature extraction prior to classification. A real time, on-line EEG analysis strategy is described which incorporates feature extracting algorithms derived from models of human EEG interpretation. A system based upon this strategy has been implemented on a dedicated minicomputer. It includes: 1) spectral analysis using the Fast Fourier Transform (FFT) to produce continuous estimates of power and coherence; 2) parallel time domain analysis to detect the occurrence of sharp transient events of possible clinical significance; 3) continuous isometric display of spectral and transient functions; 4) spectral and time domain algorithms for the rejection of noncortical and instrumental artifact; 5) heuristics to isolate patterns and events of potential clinical significance; 6) interactive alteration of analysis and display parameters to facilitate manipulation of data from various experimental paradigms; 7) on-line feedback to alter, when necessary, artifact rejection, transient detection and feature extraction decision thresholds.
{"title":"Heuristic real time feature extraction of the electroencephalogram (EEG)","authors":"A. Gevins, C. Yeager, S. Diamond","doi":"10.1145/1408800.1408833","DOIUrl":"https://doi.org/10.1145/1408800.1408833","url":null,"abstract":"The extremely complex nature of the electroencephalogram (EEG), and the subtle, nonquantified methods of pattern recognition used by human interpreters have made EEG analysis resistant to automation. Attempts at pattern recognition using multivariate classification procedures have not produced generalizable results due to the inadequate degree and quality of feature extraction prior to classification.\u0000 A real time, on-line EEG analysis strategy is described which incorporates feature extracting algorithms derived from models of human EEG interpretation. A system based upon this strategy has been implemented on a dedicated minicomputer. It includes: 1) spectral analysis using the Fast Fourier Transform (FFT) to produce continuous estimates of power and coherence; 2) parallel time domain analysis to detect the occurrence of sharp transient events of possible clinical significance; 3) continuous isometric display of spectral and transient functions; 4) spectral and time domain algorithms for the rejection of noncortical and instrumental artifact; 5) heuristics to isolate patterns and events of potential clinical significance; 6) interactive alteration of analysis and display parameters to facilitate manipulation of data from various experimental paradigms; 7) on-line feedback to alter, when necessary, artifact rejection, transient detection and feature extraction decision thresholds.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"2 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":"121066604","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}
In order for the nodes of a distributed computer network to communicate, each node must have information about the network's topology. Since nodes and links sometimes crash, a scheme is needed to update this information. One of the major constraints on such a scheme is that it may not involve a central controller. In this report a straightforward scheme involving adjacency matrices and a broadcast scheme are discussed and their inadequacies described. The NETCHANGE Protocol which is based on Baran's “Hot Potato Heuristic Routing Doctrine,” is presented. This system has been implemented on the MERIT Computer Network and its correctness has been proved. We end by showing how the NETCHANGE Protocol can be modified into a shortest path algorithm.
{"title":"The design of a topology information maintenance scheme for a distributed computer network","authors":"W. Tajibnapis","doi":"10.1145/800182.810425","DOIUrl":"https://doi.org/10.1145/800182.810425","url":null,"abstract":"In order for the nodes of a distributed computer network to communicate, each node must have information about the network's topology. Since nodes and links sometimes crash, a scheme is needed to update this information. One of the major constraints on such a scheme is that it may not involve a central controller.\u0000 In this report a straightforward scheme involving adjacency matrices and a broadcast scheme are discussed and their inadequacies described. The NETCHANGE Protocol which is based on Baran's “Hot Potato Heuristic Routing Doctrine,” is presented. This system has been implemented on the MERIT Computer Network and its correctness has been proved.\u0000 We end by showing how the NETCHANGE Protocol can be modified into a shortest path algorithm.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"49 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":"131749255","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}
The FORUM project at the Institute for the Future is currently at the second year of a three-year effort to study the effectiveness of computer conferencing udder various types of group conditions. For the last twelve months we have had the opportunity to observe the behavior of a variety of user groups communicating through the FORUM system made available to them on an international computer network. This presentation will review the findings of an analysis effort based on ten experimental computer conferences for which monitor statistics are available.
{"title":"Results from a program of computer conference experiments: statistical observations of user behavior under the FORUM system","authors":"J. Vallee","doi":"10.1145/1408800.1408911","DOIUrl":"https://doi.org/10.1145/1408800.1408911","url":null,"abstract":"The FORUM project at the Institute for the Future is currently at the second year of a three-year effort to study the effectiveness of computer conferencing udder various types of group conditions. For the last twelve months we have had the opportunity to observe the behavior of a variety of user groups communicating through the FORUM system made available to them on an international computer network. This presentation will review the findings of an analysis effort based on ten experimental computer conferences for which monitor statistics are available.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"109 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":"123013064","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}
Can the process by which scientific hypotheses are developed be made explicit? This paper investigates the issue by assuming hypotheses come from data, utilizing an information processing framework, and setting up a laboratory simulation in which subjects infer mathematical functions from plots of coordinate values. Protocol information collected in this setting provide the basis for a computer model of the sequence leading from the data to hypotheses. The model has five steps including the identification of the data's significant features and their organization into a coherent pattern, inferring of a general class of hypotheses, determination of a specific hypothesis from the class, testing by means of comparing hypotheses' predictions with the data, and iteration if necessary. Tests of the model indicate it gets the same answer as subjects most of the time and follows some of the process used by subjects in obtaining answers.
{"title":"Simulation of the hypothesis generation process","authors":"D. Gerwin","doi":"10.1145/1408800.1408825","DOIUrl":"https://doi.org/10.1145/1408800.1408825","url":null,"abstract":"Can the process by which scientific hypotheses are developed be made explicit? This paper investigates the issue by assuming hypotheses come from data, utilizing an information processing framework, and setting up a laboratory simulation in which subjects infer mathematical functions from plots of coordinate values. Protocol information collected in this setting provide the basis for a computer model of the sequence leading from the data to hypotheses. The model has five steps including the identification of the data's significant features and their organization into a coherent pattern, inferring of a general class of hypotheses, determination of a specific hypothesis from the class, testing by means of comparing hypotheses' predictions with the data, and iteration if necessary. Tests of the model indicate it gets the same answer as subjects most of the time and follows some of the process used by subjects in obtaining answers.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"422 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":"122872798","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}
Nested dissection is an ordering technique used to order the sparse symmetric positive definite systems of linear equations arising from discretizations to elliptic boundary value problems yielding regular n × n grids. By taking a recursive view of nested dissection we develop an ordering strategy which is particularly simple and efficient when n &equil; 2@−1. A FORTRAN IV subroutine of our algorithm is included and some experiments are presented.
{"title":"Automatic nested dissection","authors":"D. Rose, G. G. Whitten","doi":"10.1145/800182.810384","DOIUrl":"https://doi.org/10.1145/800182.810384","url":null,"abstract":"Nested dissection is an ordering technique used to order the sparse symmetric positive definite systems of linear equations arising from discretizations to elliptic boundary value problems yielding regular n × n grids. By taking a recursive view of nested dissection we develop an ordering strategy which is particularly simple and efficient when n &equil; 2@−1. A FORTRAN IV subroutine of our algorithm is included and some experiments are presented.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"22 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":"116427680","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}
The intent of this paper is to propose a simple mechanical procedure by which type checking predicates can be constructed for extensible sets of data types. Type checking under these circumstances is nontrivial because the potentially infinite (or at least very large) number of types makes it impossible (or at least very expensive) to encode type information into a fixed length tag that could be associated with each data item. To give substance to the discussion, the proposal is developed in terms of several basic data types and constructors for recursively defining aggregate data types of arbitrary structural complexity. A predicate for an aggregate type is defined in terms of the predicates for its various constituent types. It is hoped that the procedure discussed here could be exploited in a type-checking mechanism for any environment in which new data types can be synthesized out of existing ones.
{"title":"Mechanical construction of type-checking predicates for extensible data types","authors":"C. R. Hollander","doi":"10.1145/800182.810389","DOIUrl":"https://doi.org/10.1145/800182.810389","url":null,"abstract":"The intent of this paper is to propose a simple mechanical procedure by which type checking predicates can be constructed for extensible sets of data types. Type checking under these circumstances is nontrivial because the potentially infinite (or at least very large) number of types makes it impossible (or at least very expensive) to encode type information into a fixed length tag that could be associated with each data item. To give substance to the discussion, the proposal is developed in terms of several basic data types and constructors for recursively defining aggregate data types of arbitrary structural complexity. A predicate for an aggregate type is defined in terms of the predicates for its various constituent types. It is hoped that the procedure discussed here could be exploited in a type-checking mechanism for any environment in which new data types can be synthesized out of existing ones.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"60 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":"126322910","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}
This work describes the access control system being implemented in INGRES (INteractive Graphics and REtrieval System). The scheme can be applied to any relational data base management system and has several advantages over other suggested schemes. These include: a) implementation ease b) small execution time overhead c) powerful and flexible controls d) conceptual simplicity The basic idea utilized is that a user interaction with the data base is modified to an alternate form which is guaranteed to have no access violations. This modification takes place in a high level interaction language. Hence, the processing of a resulting interaction can be accomplished with no further regard for protection. In particular, any procedure calls in the access paths for control purposes, such as in [1,2], are avoided.
{"title":"Access control in a relational data base management system by query modification","authors":"M. Stonebraker, E. Wong","doi":"10.1145/800182.810400","DOIUrl":"https://doi.org/10.1145/800182.810400","url":null,"abstract":"This work describes the access control system being implemented in INGRES (<Underline>IN</Underline>teractive <Underline>G</Underline>raphics and <Underline>RE</Underline>trieval <Underline>S</Underline>ystem). The scheme can be applied to any relational data base management system and has several advantages over other suggested schemes.\u0000 These include: a) implementation ease\u0000b) small execution time overhead\u0000c) powerful and flexible controls\u0000d) conceptual simplicity\u0000The basic idea utilized is that a user interaction with the data base is modified to an alternate form which is guaranteed to have no access violations. This modification takes place in a high level interaction language. Hence, the processing of a resulting interaction can be accomplished with no further regard for protection. In particular, any procedure calls in the access paths for control purposes, such as in [1,2], are avoided.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"65 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":"134065975","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}
W. Reitman, J. Kerwin, Robert A. Nado, J. Reitman, Bruce Wilcox
A program that plays Go provides a basis for analyzing possibilities for extending present AI conceptions of planning and goal structures to problems that are ill-structured, dynamic, multiperson, resource-bound, and highly interactive. The focus is on mechanisms for communicating information and control over time and among a number of interacting processes, in a flexible but coherent manner. Using the capabilities of current computer languages, it is possible to specify planning and goal structures, and appropriate conventions for them, that will accommodate the demands of these increasingly complex and sophisticated problem environments.
{"title":"Goals and plans in a program for playing Go","authors":"W. Reitman, J. Kerwin, Robert A. Nado, J. Reitman, Bruce Wilcox","doi":"10.1145/800182.810391","DOIUrl":"https://doi.org/10.1145/800182.810391","url":null,"abstract":"A program that plays Go provides a basis for analyzing possibilities for extending present AI conceptions of planning and goal structures to problems that are ill-structured, dynamic, multiperson, resource-bound, and highly interactive. The focus is on mechanisms for communicating information and control over time and among a number of interacting processes, in a flexible but coherent manner.\u0000 Using the capabilities of current computer languages, it is possible to specify planning and goal structures, and appropriate conventions for them, that will accommodate the demands of these increasingly complex and sophisticated problem environments.","PeriodicalId":204185,"journal":{"name":"ACM '74","volume":"4 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":"131939885","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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