ppxscal/embedding_network huggingface dataset:
A model of OASIS role-based access control and its support for active security
Authors: Walt Yao, Ken Moody, Jean Bacon
Venue: Proceedings of the sixth ACM symposium on Access control models and technologies (2001)

OASIS is a role-based access control architecture for achieving secure interoperation of services in an open, distributed environment. Services define roles and implement formally specified policy for role activation and service use; users must present the required credentials, in the specified context, in order to activate a role or invoke a service. Roles are activated for the duration of a session only. In addition, a role is deactivated immediately if any of the conditions of the membership rule associated with its activation becomes false.OASIS does not use role delegation but instead defines the notion of appointment, whereby a user in some role may issue an \actright{} to some other user. The role activation conditions of services may include \actright{}s, prerequisite roles and environmental constraints.We motivate our approach and formalise OASIS. First, a basic model is presented followed by an extended model which includes parameterisation.
Designing a Bloom filter for differential file access
Authors: Lee L. Gremillion
Venue: Communications of the ACM (1982)

The use of a differential file for a database update can yield integrity and performance benefits, but it can also present problems in providing current data to subsequent accessing transactions. A mechanism known as a Bloom filter can solve these problems by preventing most unnecessary searches of the differential file. Here, the design process for a Bloom filter for an on-line student database is described, and it is shown that a very effective filter can be constructed with a modest expenditure of system resources.
Dimensional analysis in computer algebra
Authors: Raya Khanin
Venue: Proceedings of the 2001 international symposium on Symbolic and algebraic computation (2001)

The goal of this paper is to demonstrate the introduction of dimensional variables as well as the applications of dimensional analysis in Computer Algebra system (Mathematica). The package Dimensional Analysis developed by author uses nondimensionalization based on II-theorem to simplify equations and to reduce the number of parameters when the governing equations are not known. The package contains symbols, dimensional formulae and units for principal physical quantities, as well as a number of named dimensionless parameters. Another important feature of the package is its ability to check the dimensional homogeneity of the expressions. This package is aimed at helping researchers with the preliminary analysis of models and simplification of large-scale problems by using dimensionless parameters. The package can also be used in teaching.
A performance-driven standard-cell placer based on a modified force-directed algorithm
Authors: Yih-Chih Chou, Youn-Long Lin
Venue: Proceedings of the 2001 international symposium on Physical design (2001)

We propose a performance-driven cell placement method based on a modified force-directed approach. A pseudo net is added to link the source and sink flip-flops of every critical path to enforce their closeness. Given user-specified I/O pad locations at the chip boundaries and starting with all core cells in the chip center, we iteratively move a cell to its force-balanced location assuming all other cells are fixed. The process stops when no cell can be moved farther than a threshold distance. Next, cell rows are adjusted one at a time starting from the top and bottom. After forming these two rows (top/bottom), all movable core cells force-balanced locations are updated. The row-formation-and-update process continues until all rows are adjusted and, hence, a legal placement is obtained. We have integrated the proposed approach into an industrial APR flow. Experimental results on benchmark circuits up to 191K-cell (500K-gate) show that the critical path delay can be improved by as much as 11.5%. We also study the effect on both layout quality and CPU time consumption due to the amount of pseudo net added. We found that the introduction of pseudo net indeed significantly improves the layout quality.
The LRLTRAN compiler
Authors: Sam F. Mendicino, Robert A. Hughes, Jeanne T. Martin, Frank H. McMahon, John E. Ranelletti Richard G. Zwakenberg
Venue: Communications of the ACM (1968)

Extensive software problems confront an organization which possesses a number of different computers and which frequently acquire new ones. To maintain cohesion, a system must be developed, written in a high level language, which minimizes machine dependencies and isolates those which are necessary. A language and a compiler for that language are discussed here. The language, called LRLTRAN, is a heavily augmented FORTRAN. The three-pass compiler makes use internally of a postfix Polish notation (pass I to pass II) and a free representation referred to as a &ldquo;composite blocking table&rdquo; (pass I to pass III). Machine-independent optimization occurs in pass II and DO-loop and machine-dependent optimization in pass III.
The impact on student performance of a change of language in successive introductory computer programming subjects
Authors: Wendy Doube
Venue: Proceedings of the Australasian conference on Computing education (2000)

In 1998, in two consecutive introductory computer programming subjects, the implementation language changed from C++ to Java, in semester 1 for the first subject and semester 2 for the second subject 70% of students in the second subject had no previous exposure to Java mainly because of exemptions and part-time study mode course structure. Performance of the two groups was compared with final results from the years 1992 to 1997. No significant difference was found in the students who took Java at the first level. Although only slightly poorer, the reduced performance of the other group suggested that additional measures were required to assist their transition. Acquisition of object-oriented concepts and design approaches appeared to be the major source of difficulty. A number of compensatory measures were recommended including use of a language independent object-oriented design text and additional Java programming worked exercise.
Web-based multimedia tools for sharing educational resources
Authors: Shervin Shirmohammadi, Abdulmotaleb El Saddik, Nicolas D. Georganas, Ralf Steinmetz
Venue: Journal on Educational Resources in Computing (JERIC) (2001)

Many educational resources and objects have been developed as Java applets or applications, which can accessed by simply downloading them from various repositories. It is often necessary to share these resources in real time, for instance when an instructor teaches remote students how to use a certain resource explains the theory behind it. We have developed some tools for this purpose that emulate a virtual classroom, and are primarily designed for synchronous sharing of resources. They enable participants to share Java objects in real time and also allow the instructor to dynamically manage the telebearing session.
Experiments in automatic learning for a multipurpose hueristic program
Authors: James R. Slagle, Carl D. Farrell
Venue: Communications of the ACM (1971)

An automatic learning capability has been developed and implemented for use with the MULTIPLE (MULTIpurpose Program that LEarns) heuristic tree-searching program, which is presently being applied to resolution theorem-proving in predicate calculus. MULTIPLE's proving program (PP) uses two evaluation functions to guide its search for a proof of whether or not a particular goal is achievable. Thirteen general features of predicate calculus clauses were created for use in the automatic learning of better evaluation functions for PP. A multiple regression program was used to produce optimal coefficients for linear polynomial functions in terms of the features. Also, automatic data-handling routines were written for passing data between the learning program and the proving program, and for analyzing and summarizing results. Data was generally collected for learning (regression analysis) from the experience of PP. A number of experiments were performed to test the effectiveness and generality of the learning program. Results showed that the learning produced dramatic improvements in the solutions to problems which were in the same domain as those used for collecting learning data. Learning was also shown to generalize successfully to domains other than those used for data collection. Another experiment demonstrated that the learning program could simultaneously improve performance on problems in a specific domain and on problems in a variety of domains. Some variations of the learning program were also tested.
EULER: a generalization of ALGOL, and its formal definition: Part II
Authors: Niklaus Wirth, Helmut Weber
Venue: Communications of the ACM (1966)

In this section the algorithmic language EULER is described first informally and then formally by its syntax and semantics. An attempt has been made to generalize and extend some of the concepts of ALGOL, thus creating a language which is simpler and yet more flexible than ALGOL 60. A second objective in developing this language was to show that a useful programming language which can be processed with reasonable efficiency can be defined in rigorous formality.
Programming pearls: Aha algorithms
Authors: Jon Bentley
Venue: Communications of the ACM (1983)

The study of algorithms has much to offer the practicing programmer. After just a course or two on the subject, students take away algorithms for solving many important tasks and design techniques for attacking new problems. Advanced algorithmic tools can have a substantial impact on software systems. Next month, for instance, we'll study a system in which algorithm design helped reduce development time by 170 staff-years. As important as such tools are, algorithms can have an impact on a more common level of programming. In his book aha! Insight (from which I shamelessly stole my title), Martin Gardner describes the type of contribution I have in mind: &ldquo;a problem that seems difficult may have a simple, unexpected solution.&rdquo; Unlike the advanced methods of the field, the aha! insights of algorithms don't come only after extensive study; they're available to any programmer willing to think seriously before, during, and after coding. But enough generalities, on to the problems!
A comparative study of static and profile-based heuristics for inlining
Authors: Matthew Arnold, Stephen Fink, Vivek Sarkar, Peter F. Sweeney
Venue: ACM SIGPLAN Notices (2000)

In this paper, we present a comparative study of static and profile-based heuristics for inlining. Our motivation for this study is to use the results to design the best inlining algorithm that we can for the Jalape&ntilde;o dynamic optimizing compiler for Java [6]. We use a well-known approximation algorithm for the KNAPSACK problem as a common &ldquo;meta-algorithm&rdquo; for the inlining heuristics studied in this paper. We present performance results for an implementation of these inlining heuristics in the Jalape&ntilde;o dynamic optimizing compiler. Our performance results show that the inlining heuristics studied in this paper can lead to significant speedups in execution time (up to 1.68x) even with modest limits on code size expansion (at most 10%).
A processor allocation method for time-sharing
Authors: A. P. Mullery, G. C. Driscoll
Venue: Communications of the ACM (1970)

A scheduling algorithm is proposed which is intended to minimize changes of tasks on processors and thereby reduce overhead. The algorithm also has application to more general resource allocation problems. It is implemented by means of a method for efficiently handling dynamically changing segmented lists.
Analysis techniques for microarray time-series data
Authors: Vladmir Filkov, Steven Skiena, Jizu Zhi
Venue: Proceedings of the fifth annual international conference on Computational biology (2001)

We introduce new methods for the analysis of short-term time-series data, and apply them to gene expression data in yeast. These include (1) methods for automated period detection in a predominately cycling data set and (2) phase detection between phase-shifted cyclic data sets. We show how to properly correct for the problem of comparing correlation coefficents between pairs of sequences of different lengths and small alphabets. In particular, we show that the correlation coefficient of sequences over alphabets of size two can exhibit very counter-intuitive behavior when compared with the Hamming distance. Finally, we address the predictability of known regulators via time-series analysis, and show that less than 20% of known regulatory pairs exhibit strong correlations in the Cho/Spellman data sets. By analyzing known regulatory relationships, we designed an edge detection function which identified candidate regulations with greater fidelity than standard correlation methods.
A comparison of hardware and software associative memories in the context of computer graphics
Authors: Neil J. Stillman, P. Bruce Berra
Venue: Communications of the ACM (1977)

The Associative Processing of Line Drawings (APLD) System utilizes a hardware associative memory and creates, modifies, deletes, stores, and retrieves two-dimensional line drawings consisting of points, lines, rectangles, and triangles. The APLD functions were duplicated on the TX-2 computer at M.I.T.'s Lincoln Laboratory under the LEAP Language and Data Structure. A comparison of the hardware approach with the software simulation illustrates the advantages of the hardware associative memory in three areas: (1) processing speed, (2) storage requirements, and (3) flexibility. The major problem areas of hardware associative memory technology, namely input/output and cost effectiveness, are also addressed.
An algorithm for locating adjacent storage blocks in the buddy system
Authors: James A. Hinds
Venue: Communications of the ACM (1975)

A simple scheme for the determination of the location of a block of storage relative to other blocks is described. This scheme is applicable to the buddy type storage allocation systems.
Efficient encoding schemes for symbolic analysis of petri nets
Authors: E. Pastor, J. Cortadella
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

Petri nets are a graph-based formalism appropriate to model concurrent systems such as asynchronous circuits or network protocols. Symbolic techniques based on Binary Decision Diagrams (BDDs) have emerged as one of the strategies to overcome the state explosion problem in the analysis of systems modeled by Petri nets. The existing techniques for state encoding use a variable-per-place strategy that leads to encoding schemes with very low density. This drawback has been partially mitigated by using Zero-Suppressed BDDs, that provide a typical reduction of BDD sizes by a factor of two. This work presents novel encoding schemes for Petri nets. By using algebraic techniques to analyze the topology of the net, sets of places "structurally related" can be derived and encoded by only using a logarithmic number of boolean variables. Such approach allows to drastically decrease the number of variables for state encoding and reduce memory and CPU requirements significantly.
High Volume RF/Microwave SOI-CMOS Integrated Circuits
Authors: A. J. Auberton-Herve, T. Barge, C. Maleville, A. Wittkower
Venue: Analog Integrated Circuits and Signal Processing (2000)

Building RF/microwave SOI-CMOS integrated circuits has significant speed and power advantages over circuits built on bulk materials. High quality SOI material exists today which will meet today&rsquo;s device requirements; on-going development efforts will improve the material available for subsequent device generations.
A high-speed FIR digital filter with CSD coefficients implemented on FPGA
Authors: Mitsuru Yamada, Akinori Nishihara
Venue: Proceedings of the 2001 Asia and South Pacific Design Automation Conference (2001)

A very fast and low-complexity FIR digital filter on FPGA is presented. Multipliers in the filter whose coefficients are expressed as canonic signed digit (CSD) code are realized with wired-shifters, adders and subtracters. The critical path is minimized by insertion of pipeline registers and is equal to the propagation delay of an adder. The number of pipeline registers is limited by using an equivalent transformation on a signal flow graph. The price paid for the 100% speedup is 5% increase in the area. The maximum sampling frequency is 78.6 MHz.
A design framework to efficiently explore energy-delay tradeoffs
Authors: William Fornaciari, Donatella Sciuto, Cristina Silvano, Vittorio Zaccaria
Venue: Proceedings of the ninth international symposium on Hardware/software codesign (2001)

Comprehensive exploration of the design space parameters at the system-level is a crucial task to evaluate architectural tradeoffs accounting for both energy and performance constraints. In this paper, we propose a system-level design methodology for the efficient exploration of the memory architecture from the energy-delay combined perspective. The aim is to find a sub-optimal configuration of the memory hierarchy without performing the exhaustive analysis of the parameters space. The target system architecture includes the processor, separated instruction and data level- one caches, the main memory, and the system buses. The methodology is based on the sensitivity analysis of the optimization function with respect to the tuning parameters of the cache architecture (mainly cache size, block size and associativity). The effectiveness of the proposed methodology has been demonstrated through the design space exploration of a real-world example: a MicroSPARC2-based system running the Mediabench suite. Experimental results have shown an optimization speed up of 329 times with respect to the full search, while the near-optimal system-level configuration is characterized by a distance from the optimal full search configuration in the band of 10%.
Tools and philosophy for software education
Authors: John J. Donovan
Venue: Communications of the ACM (1976)

This paper describes a set of tools and a philosophy for teaching software that have been found very useful in courses at MIT over the past seven years. The tools include programs such as simulators, graders, compilers, and monitors. These allow the instructor to augment the basic concepts with relevant, exciting, and economical student project activities.
Effects of spatial audio on memory, comprehension, and preference during desktop conferences
Authors: Jessica J. Baldis
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2001)

An experiment was conducted to determine the effect of spatial audio on memory, focal assurance, perceived comprehension and listener preferences during desktop conferences. Nineteen participants listened to six, pre-recorded, desktop conferences. Each conference was presented using either non-spatial audio, co-located spatial audio, or scaled spatial audio, and during half of the conferences, static visual representations of the conferees were present. In the co-located condition, each conferees voice originated from directly above their image on the screen, and in the scaled spatial audio condition, the spatial separation between conferee voices was increased beyond the visual separation. Results showed that spatial audio improved all measures, increasing memory, focal assurance, and perceived comprehension. In addition, participants preferred spatial audio to non-spatial audio. No strong differences were found in the visual conditions, or between the co-located spatial condition and the scaled spatial conditions.
Load chracterization and anomaly detection for voice over IP traffic
Authors: Michel Mandjes, Iraj Saniee, Alexander Stolyar
Venue: Proceedings of the 2001 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2001)

We consider the problem of traffic anomaly detection in IP networks. Traffic anomalies arise when there is overload due to failures in a network. We present general formulae for the variance of the cumulative traffic over a fixed time interval and show how the derived analytical expression simplifies for the case of voice over IP traffic, the focus of this paper. To detect load anomalies, we show it is sufficient to consider cumulative traffic over relatively long intervals such as 5 minutes. This approach substantially extends the current practice in IP network management where only the first order statistics and fixed thresholds are used to identify abnormal behavior.
Optimal storage allocation for serial files
Authors: Haim Mendelson, Joseph S. Pliskin, Uri Yechiali
Venue: Communications of the ACM (1979)

A computer system uses several serial files. The files reside on a direct-access storage device in which storage space is limited. Records are added to the files either by jobs in batch processing mode, or by on-line transactions. Each transaction (or job) generates a demand vector which designates the space required in each file for record addition. Whenever one file runs out of space, the system must be reorganized. This paper considers several criteria for best allocating storage space to the files.
A CANDLE to light the way?
Authors: John Messing, Sebastian Abeck, Jodok Batlogg, Dirk Feuerhelm, Oliver Mehl
Venue: Proceedings of the Australasian conference on Computing education (2000)

The changing nature of education and training has challenges which have not been adequately addressed despite persistent promises that it will herald an era of globalisation. One of those challenges is the regular reuse of educational material developed elsewhere. Information Technology (IT) is in particular need of such reuse because of the rate at which the domain is changing and the inability of individual organizations to keep their educational and training material current. To accomplish this requires the development of an open, flexible and most importantly, acceptable, platform. The CANDLE project is a European Commission funded project which has taken on this challenge by designing and developing a state of the art system. The use of metadata to classify content at different levels of granularity and an information broker architecture are two components of the system.
Guava: a dialect of Java without data races
Authors: David F. Bacon, Robert E. Strom, Ashis Tarafdar
Venue: Proceedings of the 15th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications (2000)

We introduce Guava, a dialect of Java whose rules statically guarantee that parallel threads access shared data only through synchronized methods. Our dialect distinguishes three categories of classes: (1) monitors, which may be referenced from multiple threads, but whose methods are accessed serially; (2) values, which cannot be referenced and therefore are never shared; and (3) objects, which can have multiple references but only from within one thread, and therefore do not need to be synchronized. Guava circumvents the problems associated with today's Java memory model, which must define behavior when concurrent threads access shared memory without synchronization.We present an overview of the syntax and the semantic rules of Guava. We discuss how implementations of Guava can exploit these rules to re-enable compiler optimizations inhibited by standard Java. We discuss how compilers for certain multiprocessor architectures can automatically generate certain programming idioms, such as double-check reads, as optimizations of serialized monitors.