bluuebunny/crossref_metadata_2025_split huggingface dataset:
An algorithm for speculative parallel execution of rendezvous-synchronized simulation
Authors: Preiss Bruno R. 
Published: January 2007

This paper presents an approach for speculative parallel execution of rendezvous-synchronized simulations. Rendezvous-synchronized simulation is based on the notions of processes and gates and on the rendezvous mechanism defined in the basic process algebra of LOTOS—a standard formal specification language for temporal ordering
[2]
. Time is introduced via a mechanism similar to the
delay
behaviour annotation provided by the TOPO toolset
[4-6]
.

The algorithm allows speculative gate activations. This increases the available parallelism while ensuring correct execution of the computation.
The model is used to describe closed stochastic queueing network simulations. Analysis of their execution results suggests that the model makes available a promising degree of parallelism.
Comparative analysis of periodic state saving techniques in time warp simulators
Authors: Fleischmann Josef , Wilsey Philip A. 
Published: January 2007

Checkpointing in a time warp synchronized parallel simulator is a necessary and potentially expensive operation. In the simple case, a time warp simulator checkpoints every χ events, for some fixed value χ. For larger values of χ, the simulator requires less overhead for saving the state, but incurs an increased latency during rollback. Thus, the problem is to balance the time to save states against the time to coast forward upon rollback. Unfortunately, a static determination of a optimal value for χ is very difficult and can vary widely, even between closely related instances of a time warp simulator. Furthermore, the optimal checkpoint interval may actually vary over the lifetime of the simulation.
To address these problems, several investigators have proposed dynamically adjusting the checkpoint interval χ as the simulation progresses. This paper analyzes three previous techniques for dynamically sizing checkpoint intervals and presents a new, heuristic algorithm for this purpose. All four techniques are implemented in a common application domain (digital system simulation from VHDL descriptions) and a direct comparison between the algorithms is performed. The results show a significant difference in the performance of the implemented algorithms. However, in virtually all cases, the dynamic algorithms performed near or better than the best static value. Furthermore, the best algorithms performed as much as 12% better than the best static value.
Structural experiments with arrays of functions
Authors: Benkard J. Philip 
Published: January 2007

Proposals have been made to include function arrays in APL syntax. Strand syntax extends to provide vectors; bracket semantics, to provide reshaping.
Herein the structure phase of expression evaluation, which is APL's unique addition to the more familiar syntax and semantics phases, is analyzed. To the two argument shapes of VSAPL must be added the function shape. The extension of the conformance rules is straightforward; scalar conformance is the driving mechanism; applied recursively it is the basis of pervasion. Function and data arrays used with EACH and ENCLOSE, respectively, to produce scalars, lead to identities involving TRANSPOSE, DISCLOSE, and OUTER PRODUCT.
Analysis of the nonpervasive scalar function RHO EACH suggests what structural information must be retained in an empty function array. A vector of derived functions is a useful alternative to a derived function with an EACH in some common circumstances. A historical survey suggests that adding function vectors to APL2 would enhance the symmetry and balance of the language.
Sophisticated image rendering in environmental design review
Authors: Danahy John W. 
Published: January 2007

The Landscape Architecture Programme and the Computer Systems Research Institute at the University of Toronto undertook two studies using advanced rendering tools pioneered in the areas of computer animation and graphic art. Through two professional landscape architectural design studies we explored the potential role and impact of computer simulation in the initial, more creative phases of the design work. Advanced image rendering hardware and software were used to produce high quality computer drawings of design concepts. The techniques employed in this study are unique in their application to environmental design where they dramatically improve the designer's opportunities to simulate realistic images of proposed design alternatives and to consider the visual and spatial implications of such alternatives.
The case studies represented in the paper were undertaken for the National Capital Commission in Ottawa, Canada. The first project is an urban design massing study called the “Parliamentary Precinct Study” and the second project is a detailed design of the “Ceremonial Routes” in Ottawa.
Modeling multiprocessor computer systems with unbalanced flows
Authors: Madnick Stuart , Wang Y. Richard 
Published: January 2007

A performance analysis methodology using certain aspects of queueing theory to evaluate computer system speed performance is presented. This methodology specifically focuses on modeling multiprocessor computer systems with unbalanced flows (i.e., number of transactions leaving a server is not the same as number of transactions entering that server) due to asynchronously spawned parallel tasks. This unbalanced flow phenomenon, which has a significant effect on performance, cannot be solved analytically by classical queueing network models.
A decomposition method is applied to decompose the unbalanced flows. Formulae for open queueing networks with unbalanced flows due to asynchronously spawned tasks are developed. Furthermore, an algorithm based on Buzen's convolution algorithm is developed to test the necessary and sufficient condition for closed system stability as well as to compute performance measures. An average of less than four iterations is reported for convergence with this algorithm.
A Study of the INFOPLEX multiprocessor data storage hierarchy, comparing this rapid solution algorithm with simulations, has shown highly consistent results. A cost effective software tool, using this methodology, has been developed to analyze an architectural design, such as INFOPLEX, and to produce measures such as throughput, utilization, and response time so that potential performance problems can be identified.
Cluster reserves
Authors: Aron Mohit , Druschel Peter , Zwaenepoel Willy 
Published: January 2007

In network (e.g., Web) servers, it is often desirable to isolate the performance of different classes of requests from each other. That is, one seeks to achieve that a certain minimal proportion of server resources are available for a class of requests, independent of the load imposed by other requests. Recent work demonstrates how to achieve this performance isolation in servers consisting of a single, centralized node; however, achieving performance isolation in a distributed, cluster based server remains a problem.
This paper introduces a new abstraction, the cluster reserve, which represents a resource principal in a cluster based network server. We present a design and evaluate a prototype implementation that extends existing techniques for performance isolation on a single node server to cluster based servers.
In our design, the dynamic cluster-wide resource management problem is formulated as a constrained optimization problem, with the resource allocations on individual machines as independent variables, and the desired cluster-wide resource allocations as constraints. Periodically collected resource usages serve as further inputs to the problem.
Experimental results show that cluster reserves are effective in providing performance isolation in cluster based servers. We demonstrate that, in a number of different scenarios, cluster reserves are effective in ensuring performance isolation while enabling high utilization of the server resources.
An analytical model of the working-set sizes in decision-support systems
Authors: Karlsson Magnus , Stenström Per 
Published: January 2007

This paper presents an analytical model to study how working sets scale with database size and other applications parameters in decision-support systems (DSS). The model uses application parameters, that are measured on down-scaled database executions, to predict cache miss ratios for executions of large databases.
By applying the model to two database engines and typical DSS queries we find that, even for large databases, the most performance-critical working set is small and is caused by the instructions and private data that are required to access a single tuple. Consequently, its size is not affected by the database size. Surprisingly, database data may also exhibit temporal locality but the size of its working set critically depends on the structure of the query, the method of scanning, and the size and the content of the database.
Parametric Fourier image characterization toolkit
Authors: Alonso J. R. F. 
Published: January 2007

A suite of APL programs is described for characterization of bounded images for on-line process control or for artificial intelligence recognition functions. Beginning with an acquired threshold and edge enhanced image, the programs:

detect the edges and close all bounded areas in the image

produce arrays with the (x,y) locations of the boundaries of each object (bounded area) in the field, allowing for touching, segmented, perforated, embedded objects (all reported as separate arrays of sequenced coordinate pairs)

compress the image using a quad tree procedure for archival or legal purposes

fit parametric polynomial, conventional Fourier or inner product-outer product - matrix inversion Fourier equations to the object boundaries, to any desired number of coefficient terms or number of boundary pixel points.

displays results and analyses of degree of fit in a windowed environment performs accept-reject-identify checks by comparison of the calculated Fourier coefficients from “perfect” objects or from a CAD system database.

The system is written in 500 lines of IBM APL/PC Version 2 for a PC/AT with 80287 co-processor, and it is presently being interfaced to Data Translation image grabber hardware and software, with 512x512 acquisition resolution.
Parameterization fitting accuracy is increased by considering not pixel center coordinates but intersection of boundary regression lines with pixel boundaries.
The user interface makes the suite of programs manageable by a competent technical user without programming or APL knowledge.
Statistics loves APL
Authors: Douglas J. B. 
Published: January 2007

To call this paper 'STATISTICIANS LOVE APL' would be self-deluding. To call it 'SOME STATISTICIANS LOVE APL' though vague would be accurate. However a balance then might be desirable by appending '… AND SOME STATISTICIANS HATE APL'. But that title would be both too long and almost vacuous. Nevertheless, this brief historical record at a personal level of the prominent place APL has played, first in the research, second in the teaching, and third in the consultative, activities of the Department of Statistics at the University of New South Wales since 1970 will help to explain and justify such titles.
The affinity between Statistics and APL derives primarily from the correspondence between the mathematical structure of much statistical analysis and the structure of APL. Successful exploitation of this correspondence depends on how Statistics is learnt, taught and used. For example, at the teaching level an entirely theoretical course in Statistics which never does anything with numbers will only rarely make contact with computing. Similarly, a 'methods' or 'cookbook' course involving computing will depend on packages which if they use APL will typically do so invisibly. How the correspondence between mathematical structure and APL has been utilized at the University of New South Wales is sketched below.
Whilst I was on leave in 1969 from the University of New South Wales at Penn State University doing some heavy statistical computing, the Computing Center called me to say that IBM had given Penn State access to an APL interpreter for a couple of months. I had not heard of APL, but was told it was a splendid system for array manipulation, and that I could have a demonstration, and then some time for personal playing. It was enormously impressive to see how easily arrays could be processed, but because I saw no likelihood that on returning to N.S.W. I would still have access to APL I did not follow up the offer to use it. But before my return to Australia IBM (Aust.) had established the Systems Development Institute in Canberra, and was providing contracts for use of its facilities - amongst these was APL\360; and the School of Mechanical Engineering of the University of N.S.W. (via G. de Vahl Davis) was carrying out a project using APL in engineering education through W.N. Holmes of IBM.
Fault detection of MOS combinatorial networks
Authors: El-ziq Yacoub M. 
Published: January 2007

Since the technology has gone into large and very large scale
integration (LSI and VLSI), one important problem is the testing of such integrated circuits. Recently, increasing interest and attention has been given to “design for testability” or design of diagnosable digital networks.
Computer algorithms for designing diagnosable metal oxide
semiconductor (MOS) networks have recently been presented by these authors. In this paper, we discuss the testing aspect of these designed networks.
A basic cell model was presented for the purpose of simulation and
test generation. Procedures for describing the generation of a complete fault detection set for the complex cell are given. Both minimal and near-minimal solutions are presented for both fan-out free and arbritrary complex cells respectively. Also, a procedure for generating the fault detection test list for arbitrary combinational networks is given also.
Some future work problems are presented and the application of this
design technique for improving the LSI and VLSI testability is introduced.
A placement technique based on minimization and even distribution of crossovers
Authors: Wang Pao-Tsin 
Published: January 2007

The component placement problem encountered in the design of cards
PCB's, etc. is a complex one. Although many solutions have been reported, they appear to share one common characteristic, i.e., the objective functions to be optimized are usually based on the classic minimum wiring distance.
The time seems ripe for both industry and academia to realize that
better and more effective objective functions are needed. A concept of producing placement by abandoning the traditional distance based criterion is presented. The emphasis is on a minimal number of crossovers and even distributions of these crossovers along some boundaries.
Since the concept has not been implemented, there is no numerical data available for comparison. A few points of concern are raised and hopefully they will stimulate further research in the area of component placement.
APL87
Authors: Iverson Kenneth E. 
Published: January 2007

I first began developing a formal language for use in teaching in the graduate program in
Automatic Data Processing
established by Professor Howard Aiken at Harvard in 1955. This language, now known as APL, has since passed through several phases, the main ones being documented in three publications [1-3]; my book
A Programming Language
in 1962, the APL\360 manual in 1968, and the APLSV manual in 1975. The last two were co-authored with A.D. Falkoff.

The specifications of the language provided by these publications were later supplemented by more philosophical studies that discussed the design principles followed, and the major design choices made. These include
The Design of APL
[4], and the
Evolution of APL
[5], by me and Falkoff, and
The Story of o
, by E.E. McDonnell [6].

Because of implementations produced by various manufacturers, and because of attempts to inject aspects of other languages (as in APLGOL), many diverse lines of development have been pursued. These have been largely reported in manuals, in the proceedings of APL conferences, and in journals such as
APL Quote-Quad
(Association for Computing Machinery), and
Vector
(British Computing Society).

In 1978 I began a line of development which has been reported largely in documents internal to IBM Corp. [7] and to I.P. Sharp Associates [8-10], but also in APL conferences [11-13]. This work has culminated in
A Dictionary of APL
, scheduled to appear in an early issue of APL Quote-Quad [14]; in what follows it will be referred to as “the dictionary”.

The present paper is a companion study in the manner of [4-6]. A preview of it was presented in November of last year at an internal IBM conference that commemorated the 20th anniversary of the initiation of the APL timesharing service within IBM.
The major points to be discussed here include terminology, the APL alphabet, word formation, parsing rules, mixed functions, operators, and localization. In discussing decisions made in the early days by me and colleagues in the APL group in the T.J. Watson Research Center, (notably A.D. Falkoff and L.M. Breed), I will use the term we; this usage is not meant to imply their agreement with the current thinking of myself and present colleagues at I.P. Sharp Associates as presented in the dictionary.

Although there is no current implementation of the entire dictionary, several implementations embody significant parts of it, such as the application of operators to derived and user-defined functions, and the production of “mixed” arrays by expressions such as 3 4 5, '
ABCD
'. Two implementations [13, 15] are particularly close to the dictionary; the latter was used in all executed examples in this paper.
Application screen management: an APL2 approach
Authors: Deerhake Stephen 
Published: January 2007

This paper describes a comprehensive full screen management system written in APL2. It provides an application I/O interface that may be adapted to a variety of screen management specific subsystems in both interactive and background environments. Besides the usual character and numeric field support, additional field types and attributes are supported by the system described here.
This system differs from past efforts in several respects. It is written in APL2, and takes full advantage of APL2's extended data structures and vector notation for its implementation and application code interfaces. Additionally, it was designed as a generalized application-user I/O interface, and as such, provides a great deal of isolation between the application and the specific screen management subsystem employed by the screen functions. It is also easily extended to support new features, such as additional field types, as well as new screen management subsystem specific facilities as they become available. To date, such extensions have been made without impacting the existing application base. In actual application usage, these functions have been found to be easy to use, and have in most instances resulted in simpler application code than would have been possible otherwise.
Managing APL public code for an in-house APL system (before and after LOGOS)
Authors: Stoneburner D. F. 
Published: January 2007

This paper will present APL Public Library management concepts used in a large in-house APL system development environment and describe a number of tools developed for this purpose. Public libraries, workspaces, functions and variables are discussed as well as documentation, reporting of changes, audit records, backup versions, and test versions. User tools discussed include functions for describing APL public files, libraries, workspaces, functions and variables, locating these objects, keyword searches, and a glossary of terms. Other user facilities include a NEWS system and an online system for submitting problem reports and requests for enhancements. Further maintenance tools include automatic generation of WSDOC listings when changes are made and automatically generated reports providing a variety of information such as libraries or workspaces lacking descriptions, lists of APL public workspaces and files with their status, function source verification, and exception reporting of workspace changes.
A discussion of LOGOS, a programming environment for APL offered by IP Sharp Associates, is also presented and how it enhances the capabilities previously described.
A survival strategy for APL
Authors: Bowman Dick 
Published: January 2007

Echoing the concerns of the conference Call for Papers, APL no longer holds the market niche which it once had - over the past few years new developments in the world of computing have overtaken many of the areas which were once our exclusive province.
Given that the computing industry is one which focuses hard on 'winners', we have to ask ourselves whether or not there is a long-term place for APL, what that place might be and how we can attain it.
The contention of this paper is that an honorable future for APL can be found and that we can reach this position more easily if we work toward it together the exact path to be outlined here is not necessarily the 'correct' one but at the present stage of the game our most urgent need is to consider as many of the facts as we can muster.
Semicolon-bracket notation
Authors: Falkoff A. D. 
Published: January 2007

The semicolon-bracket (SB) notation for indexing an array in APL has often been regarded unfavorably because of its anomalous character relative to other APL functions: the function symbol is a pair of brackets rather than a single character; the bracket pair is bound to the associated array at a higher precedence than any other function; and the requisite number of semicolons must appear literally within the brackets, so that the construct within the brackets when one or more semicolons are present is not an APL object, and therefore cannot be substituted for by another APL expression without semicolons. Nevertheless, this notation provides a simple way to index arrays of any rank, and has proven to be very convenient in practice.
In this paper, it will be shown that the SB notation can (a) easily be extended to defined functions, and that it can also be used (b) to allow a multiplicity of names to be used unambiguously to the left of assignment, (c) to allow multiple statements on a line in a manner similar to that provided by the diamond separator in some APL systems, and (d) to extend and generalize the use of bracketed expressions as an axis operator.
NUMETH a user oriented programming system for interactive application of numerical methods
Authors: Kilberth Klaus 
Published: January 2007

NUMETH is a self-explanatory dialog system, based on APL, which was developed at the Zentralinstitut für Angewandte Mathematik of the Kernforschungsanlage Jülich.
The purpose of this system is to provide an easy access to numerical methods for the handling of experimental data even to users less experienced in mathematics or in programming.
Concept and several components of NUMETH are presented.