bluuebunny/crossref_metadata_2025_split huggingface dataset:
The A+ programming language, a different APL
Authors: Girardot Jean-Jacques 
Published: January 2007

This paper introduces A+, which is an Array Oriented programming language derived from APL, and explains the motivations for creating such a language.
After discussing of some problems of current APL system, like the lack of control structures, the usage of dynamic binding, and the difficulty of handling functions, we present how these problems are solved in A+.
The most important feature of A+ is that it uses lexical binding rather than dynamic binding as APL does, which solves some old problems of APL while making it a safer language, and offers a new kind of programming style.
Preliminary mesh checking for structural analysis
Authors: Capra Renato 
Published: January 2007

The purpose of this work is to provide tools for checking the nodes and elements of a Finite Element Model for Structural Analysis.
All the checks related to single elements (warping and stretch factor, interior angles) can be performed on the whole model with APL scalar functions (without any loop).
Operations that involve comparison between elements (such as checking for coincident nodes and coincident elements) require a non-trivial approach. A simple algorithm for recursive space-splitting is described, along with performance considerations for large models.
Graphic output obtained using the Graphics Support Library of RTPC and an interface to Interleaf Workstation Publishing System are also provided.
Analytic response time model for distributed systems
Authors: Cook Janice H. , Groner Leo H. 
Published: January 2007

Network designers are faced with a combinatorial explosion of choices not only among various vendors' workstations, hosts and servers, but also among application distribution strategies, communication media, communication protocols, and network topologies. To study performance trade-offs among various designs, the authors have developed a generic system thruput and response time model for distributed systems. We have applied the model to actual customer networks.
The modeller describes the system in a language of model statements describing operations, resources, submodels, parameters and transactions flows. Model statements are “compiled” into arrays that form the input to the analytical queueing network model.
The modeling package is written in APL2 and is based on an earlier VSAPL package developed for manufacturing planning. Since the package is designed with an open set of submodel types, and since APL2 is portable across many architectures and operating systems, we can easily integrate non-APL2 code.
Arrays and references
Authors: Girardot Jean-Jacques 
Published: January 2007

Generalized arrays in APL have been for long a very controversial subject. Since we are now undertaking the redaction of an extended standard for APL, it seems legitimate to reopen the old debate.
An analysis of both nested and boxed array systems, in the light of a new development in APL which consists of the introduction of a new data-type in the language, shows the interest of having both systems with their own specificities.
Sparse matrix technology tools in APL
Authors: Hendriks Ferdinand , Ching Wai-Mee 
Published: January 2007

We have implemented sparse matrix technology tools in APL. Such tools have been conspicuously scarce, because APL has not been the language of choice for solving boundary value problems governed by partial differential equations. But when carefully coded, APL is able to tackle problems governed by partial differential equations in a way that ads flexibility and, on account of its compactness, maintainability. The main criticism of APL in numerically intensive applications has been execution speed. APL compilation addresses this drawback and shows factors of speed improvement of better than about three. Timings will be presented for some benchmark elliptical boundary value problems, both for interpretive and compiled APL.
Examples are given of common tasks that are encountered in conjunction with the finite element method, such as determination of the symbolic form of the stiffness matrix, and the more universal task of solution of a sparse (symmetric) set of equations using the conjugate gradient method.
End-user KESSU
Authors: Kaski Eeva-Liisa 
Published: January 2007

Since 1982, when the Finnish macro-economic model (KESSU) was presented in Heidelberg, its DP system has undergone substantial changes: it now runs wholly in APL both on mainframe and in micros (PC/AT, PS2/80).
A short history of the model used by the Finnish Ministry of Finance and its ADP history is presented in the paper.
The present version of the model management system is less complicated for the user than a teller machine. Behind the deceptively simple menu facade runs a complicated and powerful model, whose successive generations had been used as an instrument for economic policy design during a quarter of a century.
The system has common modules containing the model logic and environment dependent variable modules that conceal interpreter specific features such as device controls. This technique allows the use of KESSU in different environments, from PCs to IBM 3090s.
Next version of the model is in the pipeline and it's introduction will take place in near future. Some technical improvements such as generation of executable APL code from a very concise vector notation will be presented in the paper.
Programming ecology or APL and the world at large
Authors: Lucas Jim 
Published: January 2007

APL, like any programming language, interacts with various environments and individuals. How it does so and how it evolves in response to these external influences are important to the continuing health and survival of the language. It can also have a profound effect on the evolution of these same environments and individuals, since APL is a part of their universe, just as they are part of its universe.
This paper examines the demands and opportunities of interacting with these external influences and the means by which APL has tried to deal with them as a set of mutually interdependent systems, i.e., an ecology. It also proposes some future evolutionary directions for APL which should not only insure its survival but gain it a dominant position in the programming ecology. Not the least conclusion is that APL must be responsible for its own success.
A parallel APL machine
Authors: Sauermann Jügen 
Published: January 2007

The suitability of APL as a programming language for parallel computers seems to be obvious. Nevertheless, integral concepts of parallel APL machines are rare. Some ideas published so far are either not feasible with today's technology (e.g. needing large crossbar switches, which are expensive) or not detailed enough to prove their feasibility
At SaarbrUcken university, we developed a 32-processor prototype of a parallel APL machine along with a high performance network designed for up to 256 processors. Besides building the prototype (which shows the feasibility with today's technology), we specified in detail, in which way the parallel APL machine is operating.
In this paper, we present the basic principles of the parallel APL machine together with the efficiency of the machine for the most important APL functions. The details are described in [Sa].
A shading approach to non-convex clipping
Authors: Springall Thomas L. , Tollet Gustav 
Published: January 2007

The conventional way of clipping a graphic object with a rectangular window or any convex polygon is to cut the object along a line tangent to each side of the polygon. Parts of the object on the exterior side of the line are thrown away. After repeating the process for all of the sides, what remains is the clipped object.
However, this process fails if the clipping window is non-convex, i.e., has one or more corners that point inward, or if the window consists of more than one polygon. Too much then gets clipped away. One way of dealing with this situation is to break up the window into simple convex polygons. The object is clipped with each polygon in turn, and the results are joined together to form the final result.
A different approach, presented here, is to use shading logic. The window is seen as an area to be shaded, and the object, as the shading pattern. That is, the window is shaded with the object. The method yields not only the clipped object, but also, as a by-product, the reverse clipping, i.e., that part of the object that lies outside the window. This is an advantage in graphics editing where both clippings are often needed in parallel.
Very high quality user interfaces and fast data filing using a PC
Authors: Österman Jonny 
Published: January 2007

The user response to a computer system is very dependent on the user interface. In order to compete with other software products for the PC, it is important that it is easy for APL programmers to use the possibilities in the PC environment. These possibilities include a number of qualities which are not available in the mainframe environment.
With a PC, speed is usually more important than in a mainframe. This increases the demand for fast file handling functions. This paper introduces a new way to implement fast and flexible file handling for data files with a fixed record length.
A Bayesian approach to fault classification
Authors: Lin Tein-Hsiang , Shin Kang G. 
Published: January 2007

According to their temporal behavior, faults in computer systems are classified into permanent, intermittent, and transient faults. Since it is impossible to identify the type of a fault upon its first detection, the common practice is to retry the failed instruction one or more times and then use other fault recovery methods, such as rollback or restart, if the retry is not successful. To determine an “optimal” (in some sense) number of retries, we need to know several fault parameters, which can be estimated only after classifying all the faults detected in the past.
In this paper we propose a new fault classification scheme which assigns a fault type to each detected fault based on its detection time, the outcome of retry, and its detection symptom. This classification procedure utilizes the Bayesian decision theory to sequentially update the estimation of fault parameters whenever a detected fault is classified. An important advantage of this classification is the early identification of presence of an intermittent fault so that appropriate measures can be taken before it causes a serious damage to the system. To assess the goodness of the proposed scheme, the probability of incorrect classification is also analyzed and compared with simulation results.
Quartz: a tool for tuning parallel program performance
Authors: Anderson Thomas E. , Lazowska Edward D. 
Published: January 2007

Initial implementations of parallel programs typically yield disappointing performance. Tuning to improve performance is thus a significant part of the parallel programming process. The effort required to tune a parallel program, and the level of performance that eventually is achieved, both depend heavily on the quality of the instrumentation that is available to the programmer.
This paper describes Quartz, a new tool for tuning parallel program performance on shared memory multiprocessors. The philosophy underlying Quartz was inspired by that of the sequential UNIX tool gprof: to appropriately direct the attention of the programmer by efficiently measuring just those factors that are most responsible for performance and by relating these metrics to one another and to the structure of the program. This philosophy is even more important in the parallel domain than in the sequential domain, because of the dramatically greater number of possible metrics and the dramatically increased complexity of program structures.

The principal metric of Quartz is
normalized processor time
: the total processor time spent in each section of code divided by the number of other processors that are concurrently busy when that section of code is being executed. Tied to the logical structure of the program, this metric provides a “smoking gun” pointing towards those areas of the program most responsible for poor performance. This information can be acquired efficiently by checkpointing to memory the number of busy processors and the state of each processor, and then statistically sampling these using a dedicated processor.

In addition to describing the design rationale, functionality, and implementation of Quartz, the paper examines how Quartz would be used to solve a number of performance problems that have been reported as being frequently encountered, and describes a case study in which Quartz was used to significantly improve the performance of a CAD circuit verifier.
Dynamic partitioning in a transputer environment
Authors: Dussa K. , Carlson B. , Dowdy L. , Park K.-H. 
Published: January 2007

Parallel programs are characterized by their speedup behavior. As more processors are allocated to a particular parallel program, the program (potentially) executes faster. However, there is often a point of diminishing returns, beyond which extra allocated processors cannot be used effectively. Extra processors would be better utilized by allocating them to another program. Thus, given a set of processors in a multiprocessor system, and a set of parallel programs, a partitioning problem naturally arises which seeks to allocate processors to programs optimally.
The problem addressed in this paper is dynamic partitioning. When the number of executable parallel programs changes, the optimal partition sizes also change. To realize the new partition settings, a dynamic repartitioning of all processors is triggered. When extra processors suddenly become available to a running program due to a program departure, or when processors suddenly are taken away from a running program due to a program arrival, a nontrivial repartitioning overhead occurs. Depending upon the specific environment, this overhead cost may negate any potential repartitioning benefit.
To gain insight into this dynamic partitioning problem, a specific system, a specific workload, and a specific analytical model are studied. The specific system is an INMOS transputer system consisting of an IIP Vectra front-end, an INMOS B004 evaluation board with a single T414 transputer, and an EB8-10 board with eight T800 transputers. The specific workload consists of parallel versions of a classical N-body problem and a classical search problem. The specific analytical model is a Markov model which is parameterized using the concept of program execution signatures. The sensitivity analysis experiments both validate the model and indicate the characteristics of those workloads which benefit from dynamic partitioning.
Processor scheduling in shared memory multiprocessors
Authors: Zahorjan John , McCann Cathy 
Published: January 2007

Existing work indicates that the commonly used “single queue of runnable tasks” approach to scheduling shared memory multiprocessors can perform very poorly in a multiprogrammed parallel processing environment. A more promising approach is the class of “two-level schedulers” in which the operating system deals solely with allocating processors to jobs while the individual jobs themselves perform task dispatching on those processors.
In this paper we compare two basic varieties of two-level schedulers. Those of the first type, static, make a single decision per job regarding the number of processors to allocate to it. Once the job has received its allocation, it is guaranteed to have exactly that number of processors available to it whenever it is active. The other class of two-level scheduler, dynamic, allows each job to acquire and release processors during its execution. By responding to the varying parallelism of the jobs, the dynamic scheduler promises higher processor utilizations at the cost of potentially greater scheduling overhead and more complicated application level task control policies.
Our results, obtained via simulation, highlight the tradeoffs between the static and dynamic approaches. We investigate how the choice of policy is affected by the cost of switching a processor from one job to another. We show that for a wide range of plausible overhead values, dynamic scheduling is superior to static scheduling. Within the class of static schedulers, we show that, in most cases, a simple “run to completion” scheme is preferable to a round-robin approach. Finally, we investigate different techniques for tuning the allocation decisions required by the dynamic policies and quantify their effects on performance.
We believe our results are directly applicable to many existing shared memory parallel computers, which for the most part currently employ a simple “single queue of tasks” extension of basic sequential machine schedulers. We plan to validate our results in future work through implementation and experimentation on such a system.
Synoptic-Scale Structure and the Character of Coastally Trapped Wind Reversals
Authors: Nuss Wendell A. 
Published: January 2007

Abstract
Coastally trapped wind reversals that occur along the U.S. West Coast have been described in numerous other studies. The synoptic-scale environment and the forcing of a coastally trapped Kelvin wave are highly linked in the development of these wind reversals. However, not all wind reversals appear to behave like propagating Kelvin waves and the analysis of coastal buoy observations for three years indicates that different types of disturbances occur. Both propagating disturbances and nonpropagating disturbances occur with similar frequencies. While the synoptic-scale characteristics associated with propagating and nonpropagating wind reversals are sometimes rather subtle, several distinct differences occur that suggest a direct link between the coastal dynamics and the synoptic-scale forcing. Synoptic forcing characterized by persistent low-level offshore flow favors the development of propagating disturbances, while weak, nonsustained offshore flow characterizes nonpropagating disturbances. These differences support the idea that propagating events represent a favorable interaction between the synoptic-scale forcing and the excitation and propagation of Kelvin waves, whereas nonpropagating events either represent a less favorable interaction or are simply trapped ageostrophic flow due to the synoptic scale without a Kelvin wave response. These dynamic differences imply different stratus behavior, which is important to forecasters.
An Ensemble-Based Smoother with Retrospectively Updated Weights for Highly Nonlinear Systems
Authors: Chin T. M. , Turmon M. J. , Jewell J. B. , Ghil M. 
Published: January 2007

AbstractMonte Carlo computational methods have been introduced into data assimilation for nonlinear systems in order to alleviate the computational burden of updating and propagating the full probability distribution. By propagating an ensemble of representative states, algorithms like the ensemble Kalman filter (EnKF) and the resampled particle filter (RPF) rely on the existing modeling infrastructure to approximate the distribution based on the evolution of this ensemble. This work presents an ensemble-based smoother that is applicable to the Monte Carlo filtering schemes like EnKF and RPF. At the minor cost of retrospectively updating a set of weights for ensemble members, this smoother has demonstrated superior capabilities in state tracking for two highly nonlinear problems: the double-well potential and trivariate Lorenz systems. The algorithm does not require retrospective adaptation of the ensemble members themselves, and it is thus suited to a streaming operational mode. The accuracy of the proposed backward-update scheme in estimating non-Gaussian distributions is evaluated by comparison to the more accurate estimates provided by a Markov chain Monte Carlo algorithm.
Relative antithrombotic and antihemostatic effects of protein C activator versus low-molecular-weight heparin in primates
Authors: Gruber András , Marzec Ulla M. , Bush Leslie , Di Cera Enrico , Fernández José A. , Berny Michelle A. , Tucker Erik I. , McCarty Owen J. T. , Griffin John H. , Hanson Stephen R. 
Published: January 2007

AbstractThe anticoagulant and anti-inflammatory enzyme, activated protein C (APC), naturally controls thrombosis without affecting hemostasis. We therefore evaluated whether the integrity of primary hemostasis was preserved during limited pharmacological antithrombotic protein C activator (PCA) treatment in baboons. The double-mutant thrombin (Trp215Ala/Glu217Ala) with less than 1% procoagulant activity was used as a relatively selective PCA and compared with systemic anticoagulation by APC and low-molecular-weight heparin (LMWH) at doses that inhibited fibrin deposition on thrombogenic segments of arteriovenous shunts. As expected, both systemic anticoagulants, APC (0.028 or 0.222 mg/kg for 70 minutes) and LMWH (0.325 to 2.6 mg/kg for 70 minutes), were antithrombotic and prolonged the template bleeding time. In contrast, PCA at doses (0.0021 to 0.0083 mg/kg for 70 minutes) that had antithrombotic effects comparable with LMWH did not demonstrably impair primary hemostasis. PCA bound to platelets and leukocytes, and accumulated in thrombi. APC infusion at higher circulating APC levels was less antithrombotic than PCA infusion at lower circulating APC levels. The observed dissociation of antithrombotic and antihemostatic effects during PCA infusion thus appeared to emulate the physiological regulation of intravascular blood coagulation (thrombosis) by the endogenous protein C system. Our data suggest that limited pharmacological protein C activation might exhibit considerable thrombosis specificity.
CD33 expression and P-glycoprotein–mediated drug efflux inversely correlate and predict clinical outcome in patients with acute myeloid leukemia treated with gemtuzumab ozogamicin monotherapy
Authors: Walter Roland B. , Gooley Ted A. , van der Velden Vincent H. J. , Loken Michael R. , van Dongen Jacques J. M. , Flowers David A. , Bernstein Irwin D. , Appelbaum Frederick R. 
Published: January 2007

AbstractGemtuzumab ozogamicin (GO) contains an anti-CD33 antibody to facilitate uptake of a toxic calicheamicin-γ1 derivative. While recent in vitro data demonstrated a quantitative relationship between CD33 expression and GO cytotoxicity, previous correlative studies failed to identify a significant association between CD33 expression and clinical outcome. Studying patients undergoing GO monotherapy for relapsed acute myeloid leukemia (AML), we now find that AML blasts of responders have a significantly higher mean CD33 level and lower P-glycoprotein (Pgp) activity compared with nonresponders. CD33 expression and Pgp activity are inversely correlated. While both variables are associated with outcome, Pgp remains significantly associated with outcome even after adjusting for CD33, whereas CD33 does not show such an association after adjusting for Pgp. The inverse relationship between CD33 and Pgp suggests a maturation-stage–dependent expression of both proteins, and offers the rationale for using cell differentiation–promoting agents to enhance GO-induced cytotoxicity.