ppxscal/embedding_network huggingface dataset:
The complexity of almost linear diophantine problems
Authors: V. Weispfenning
Venue: Journal of Symbolic Computation (1990)

We studied formulas of elementary number theory resulting from formulas of Presburger arithmetic PrA (additive elementary theory of integers with order) by substituting for some variables, polynomials and integer values of rational functions in a single new variable y, and quantifying over y. We show that the extension ALA (almost linear arithmetic) of PrA obtained in this way, has essentially the same upper and lower complexity bounds as the original theory. The same applies to the fragments of ALA obtained by restricting the number or type of quantifiers in formulas. We also show new upper complexity bounds for quantifier elimination in PrA and its fragments. The results form a common extension of known complexity bounds for PrA and for the existential almost linear problems studied by Gurari & Ibarra. The method is applicable also to other extensions of PrA without order, related to the famous bounds for binary forms of A. Baker.
Ada 9X reusable components
Authors: Jeffrey R. Carter
Venue: ACM SIGAda Ada Letters (1992)

The inclusion of concurrency in Ada leads to multiple reusable components which implement th e same abstraction. The proposed modifications of Ada 9X contain features which may eliminate th e need for more than one version of an abstraction. An example of an Ada 9X component illustrates the use of these features.
A situated-automata approach to the design of embedded agents
Authors: Leslie Pack Kaelbling
Venue: ACM SIGART Bulletin (1991)

This paper addresses Laird's issues concerning integrated intelligent architectures in the context of work done by the Situated Automata group at SRI International, CSLI, and Teleos Research. The first section contains a brief general introduction to the theory and programming methodologies of the situated-automata approach, the second section discusses some terminological difficulties; and the third section addresses the specific issues.
Automatic synthesis of the inverses of APL functions
Authors: Alvin J. Surkan
Venue: Proceedings of the international conference on APL '91 (1991)

APL is used to facilitate the automatic inversion and execution of programs which are constructed by strict functional composition. Programs for performing high level functions and their inverses can be logically synthesized and then tested in arbitrary instances. APL is used to compose higher level functions by repeated left application of functions and operators designed expressly so that their syntax is limited to be monadic.A small system of auxiliary functions are sufficient to do the synthesis of inverse programs. This system operates on sequences of applicative functions which must be provided originally with their forward form coded in functional style APL. The system inverts higher level user-defined functions and generates correctly sequenced function calls which are used in testing the synthesized inverses.Using this system, the mechanistic re-formulation of the forward functions and either their exact or even their approximate inverses can be produced and then checked for consistency. Consistency in performance can be randomly tested by evaluating and confirming the validity of the identity R equiv; F-1 F R. This may be done for acceptable comparison tolerances over a representative number of objects named R to which the function F and its inverse F-1 are applied in tandem.
Performance variation across benchmark suites
Authors: Carl Ponder
Venue: ACM SIGARCH Computer Architecture News (1991)

The performance ratio between two systems tends to vary across different benchmarks. Here we study this variation as a "signature" or "fingerprint" of the systems under consideration. This "fingerprint" can be used to guess the performance of programs not represented in a benchmark suite, assess the breadth and credibility of the benchmark suite, and infer details of the system design.
Global tagging optimization by type inference
Authors: Fritz Henglein
Venue: Proceedings of the 1992 ACM conference on LISP and functional programming (1992)

Tag handling accounts for a substantial amount of execution cost in latently typed languages such as Common LISP and Scheme, espicially on architectures that provide no special hardware support.
Performance bounds on parallel self-initiating discrete-event simulations
Authors: David M. Nicol
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1991)

This paper considers the use of massively parallel architectures to execute discrete-event simulations of what we term &ldquo;self-initiating&rdquo; models. A logical process in a self-initiating model schedules its own state reevaluation times, independently of any other logical process, and sends its new state to other logical processes following the reevaluation. Our interest is in the effects of that communication on synchronization. Using a model that idealizes the communication topology of a simulation, we consider the performance of various synchronization protocols by deriving upper and lower bounds on optimal performance, upper bounds on Time Warp's performance, and lower bounds on the performance of a new consevative protocol. Our analysis of Time Warp includes some of the overhead costs of state saving and rollback; the effects of propogating rollbacks are ignored. The analysis points out sufficient conditions for the conservitive protocol to outperform Time Warp. The analysis also quantifies the sensitivity of performance to message fanout, lookahead ability, and the probability distributions underlying the simulation.
A new notion of reduction: Generating universal Gröbner bases of ideals in K[x, y]
Authors: W. Herfort, H. Penz
Venue: Journal of Symbolic Computation (1991)

In this paper a new notion of reduction depending on an arbitrary non-empty set ORD of term orderings on a polynomial ring is introduced. A general Buchberger algorithm based on this notion is devised. For a single element set ORD it specializes to the ordinary Buchberger algorithm. For ORD being the set of all term orderings a particular universal Grobner basis is constructed. We only deal with the case K[x, y] since for higher dimensions we have not been able to prove that the generalized algorithm stops after a finite number of steps. Some reasons for understanding the underlying difficulties are given.
Circuit extraction on a message-based multiprocessor
Authors: Bruce A. Tonkin
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

This paper discusses the use of a general purpose, message based multiprocessor to speed up the task of VLSI circuit extraction. The parallel algorithm incorporates the use of secondary storage to allow complete VLSI circuits to be extracted with small scale multiprocessors. The paper presents experimental results for the detection and labelling of transistor regions.
A semi distributed task allocation strategy for large hypercube supercomputers
Authors: Ishfaq Ahmad, Arif Ghafoor
Venue: Proceedings of the 1990 ACM/IEEE conference on Supercomputing (1990)

This paper presents a semi distributed approach for task scheduling in large parallel and distributed systems which is different from the conventional centralized and fully distributed approaches. The proposed strategy partitions the system into independent regions (spheres) centered at some control points. The central points called schedulers, optimally schedule tasks within their spheres and maintain state information with low overhead. We consider Hypercube systems for evaluation and using its algebraic characteristics, show that identification of spheres and their scheduling points is an NP-complete problem. An efficient solution for this problem is presented by making an exclusive use of a combinatorial structure known as Hadamard Matrix. Performance of the proposed strategy was evaluated and compared with an efficient fully distributed strategy, through simulation. In addition to yielding high performance in terms of response time, better resource utilization and throughput, the proposed strategy is shown to incur small overhead in terms of network traffic.
Edit wear and read wear
Authors: William C. Hill, James D. Hollan, Dave Wroblewski, Tim McCandless
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

We describe two applications that illustrate the idea of computational wear in the domain of document processing. By graphically depicting the history of author and reader interactions with documents, these applications offer otherwise unavailable information to guide work. We discuss how their design accords with a theory of professional work and an informational physics perspective on interface design.
Another defence of enumerated types
Authors: Markku Sakkinen
Venue: ACM SIGPLAN Notices (1991)

I claim that enumerations, while of course not strictly necessary, are an elegant and useful facility in modern programming languages. I try to show that arguments recently given against them are weak at best and bogus a t worst, for general-purpose programming. Some related issues on types in programming languages are touched as well. These make it even more questionable whether Oberon marks progress or regress in language design.
Minimizing ripple recompilation in a persistent software environment
Authors: M. Kazerooni-Zand, M. H. Samadzadeh, K. M. George
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

The ripple recompilation problem is caused by modifying one or more modules in an integrated set of modules, or it results from forming a new integrated set of modules. This problem could be significant if the modified modules are widely used in the set. The main objective of this paper is to present the systematic and efficient technique employed in ROPCO (Reuse On Persistent Code and Object code) to limit this effect in a persistent reuse environment. The problem is addressed in the context of strongly-typed and separately-compiled programming languages. The approach presented consists of two phases. In the first phase, the compilation dependency graph of all modules is generated, change sets are computed, and candidate modules are marked. In the second phase, modules that are candidates for recompilation are visited and two lists for logical and physical inconsistencies are generated. Algorithms are given for both phases. An analysis of the computational complexity of the algorithms is also included.
On the Mathematical Foundations of Smoothness Constraints for the Determination of Optical Flow and for Surface Reconstruction
Authors: M. A. Snyder
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

Gradient-based approaches to the computation of optical flow often use a minimization technique incorporating a smoothness constraint on the optical flow field. The author derives the most general form of such a smoothness constraint that is quadratic in first derivatives of the grey-level image intensity function based on three simple assumptions about the smoothness constraint: (1) it must be expressed in a form that is independent of the choice of Cartesian coordinate system in the image: (2) it must be positive definite; and (3) it must not couple different component of the optical flow. It is shown that there are essentially only four such constraints; any smoothness constraint satisfying (1), (2), or (3) must be a linear combination of these four, possibly multiplied by certain quantities invariant under a change in the Cartesian coordinate system. Beginning with the three assumptions mentioned above, the author mathematically demonstrates that all best-known smoothness constraints appearing in the literature are special cases of this general form, and, in particular, that the 'weight matrix' introduced by H.H. Nagel is essentially (modulo invariant quantities) the only physically plausible such constraint.
A low-cost usage-based replacement algorithm for cache memories
Authors: Yannick Deville
Venue: ACM SIGARCH Computer Architecture News (1990)

Mainly three replacement policies have been used in cache memories : LRU, FIFO and random. LRU achieves higher performance by being usage-based, i.e., by storing the order of the accesses to the cache blocks in order to remove the blocks that have remained unused for the longest period, However, storing this status results in a complex implementation. On the opposite, FIFO and random are non-usage-based ; their implementation is simpler, but their performance is lower. This paper presents the SIDE policy, which achieves a trade-off between the above features : by being usage-based, it yields almost the same performance as LRU. However, it is implemented almost in the same way as FIFO which yields simplicity and makes it easy to design a cache chip performing SIDE or FIFO replacement, depending on the mode chosen.
UIST '90, the annual symposium on user interface software and technology
Authors: Ellis S. Cohen
Venue: ACM SIGCHI Bulletin (1991)

UIST, the ACM Annual Symposium on User Interface Software and Technology, is the flagship conference for those interested in constructing innovative systems that explore ideas which are at the heart of evolving user interfaces.
Comments on 'An Architecture for Addition and Subtraction of Long Word Length Numbers in the Logarithmic Number System' by D.M. Lewis
Authors: M. Arnold, T. Bailey, J. Cowles
Venue: IEEE Transactions on Computers (1992)

D.M. Lewis recently described an architecture for performing addition and subtraction in the logarithmic number system using a Taylor series approximation and ROM tables. Here it is shown that a 25% improvement can be achieved in the table used to implement addition. This improvement is significant when Lewis' technique is used to implement variations of the logarithmic number system which do not require the subtraction logarithm.
Type inference in the presence of overloading, subtyping and recursive types
Authors: Stefan Kaes
Venue: Proceedings of the 1992 ACM conference on LISP and functional programming (1992)

We present a unified approach to type inference in the presence of overloading and coercions based on the concept of constrained types. We define a generic inference system, show that subtyping and overloading can be treated as a special instance of this system and develop a simple algorithm to compute principal types. We prove the decidability of type inference for the class of decomposable predicates and develop a canonical representation for principal types based on most accurate simplifications of constraint sets. Finally, we investigate the extension of our techniques to recursive types.
A paradigm for distributed debugging
Authors: Nancy J. Wahl, Stephen R. Schach
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

Three critical problems associated with distributed debugging are controlling the debugging process in the absence of a global clock; maintaining transparency so that the debugger does not change the order or timing of events, and reproducing an execution sequence to be able to verify that a fault has been corrected. A paradigm is put forward that successfully addresses these three problems. To demonstrate the feasibility of this paradigm, an instantiation has been constructed. A description is given of the resulting debugger for a dataflow language.
Disconnected operation in the Coda file system
Authors: James J. Kistler, M. Satyanarayanan
Venue: ACM SIGOPS Operating Systems Review (1991)

Disconnected operation is a mode of operation that enables a client to continue accessing critical data during temporary failures of a shared data repository. An important, though not exclusive, application of disconnected operation is in supporting portable computers. In this paper, we show that disconnected operation is feasible, efficient and usable by describing its design and implementation in the Coda File System. The central idea behind our work is that caching of data, now widely used for performance, can also be exploited to improve availability.
An accurate elementary mathematical library for the IEEE floating point standard
Authors: Shmuel Gal
Venue: ACM Transactions on Mathematical Software (TOMS) (1991)

The algorithms used by the IBM Israel Scientific Center for the elementary mathematical library using the IEEE standard for binary floating point arithmetic are described. The algorithms are based on the &ldquo;accurate tables method.&rdquo; This methodology achieves high performance and produces very accurate results. It overcomes one of the main problems encountered in elementary mathematical functions computations: achieving last bit accuracy. The results obtained are correctly rounded for almost all arguement values. Our main idea in the accurate tables method is to use &ldquo;nonstandard tables,&rdquo; which are different from the natural tables of equally spaced points in which the rounding error prevents obtaining last bit accuracy. In order to achieve a small error we use the following idea: Perturb the original, equally spaced, points in such a way that the table value (or tables values in case we need several tables) will be very close to numbers which can be exactly represented by the computer (much closer than the usual double percision representation). Thus we were able to control the error introduced by the computer representation of real numbers and extended the accuracy without actually using extended precision arithmetic.
Computer algebra applied to radiation from microstrip discontinuities
Authors: M. D. Abouzahra, R. Pavelle
Venue: Journal of Symbolic Computation (1990)

The use of microstrip lines for microwave applications is limited by a number of factors. These factors include line attenuation due to metallic loss, dielectric loss, and loss due to radiation from discontinuities and transitions. The latter loss constitutes one of the major limiting features at higher frequencies. Therefore the ability to understand radiation loss, predict it, and possibly control it is quite essential. This paper explains how a computer algebra (MACSYMA) was used to derive a closed-form expression for predicting the amount of radiation emanating from microstrip bends with arbitrary angle. The derivation of this expression is sufficiently messy and laborious that manual derivation would have been very difficult or almost impossible.
Cache coherence in systems with parallel communication channels many processors
Authors: John C. Willis, Arthur C. Sanderson, Charles R. Hill
Venue: Proceedings of the 1990 ACM/IEEE conference on Supercomputing (1990)

This paper describes and analyzes two algorithms for maintaining cache coherence in multiprocessor systems with parallel communication channels and many processors. A distributed link-list relates all cache frames representing the same main memory block. Messages traverse the list to maintain list integrity, exclusive ownership, and consistent values. Memory access semantics are equivalent to a shared memory system without caches. Reference latency, efficiency of memory use, and hardware complexity are moderate and well bounded. This work contributed to the current Scalable Coherence Interface effort; we briefly contrast the two designs.
An O(n1.5logn) 1-d compaction algorithm
Authors: Chi-Yuan Lo, Ravi Varadarajan
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

In this paper, we bound the complexity of the major algorithms of 1-d compaction in graph solution and module assembly to be &Ogr;(n15logn). An 1-d hierarchical module assembly method is shown to be free from the x-y interlock problem and achieves significant improvement in space and time requirements by exploiting hierarchy.
Using graph distance in object recognition
Authors: Ewa Kubicka, Grzegorz Kubicki, Ignatios Vakalis
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

In this paper the concept of the distance between graphs is applied to the problem of recognizing objects. An unknown object is represented by a graph H and from the data base of possible solutions {G1, &hellip;, Gn} (also graphs) we select the graph Gi for which the distance to H is the smallest. The graph Gi is the recognition of H. The distance between graphs is defined in terms of edge rotation and deletion. It is shown that this distance defines a metric on the space of all graphs. The bounds for distance between two graphs are given in terms of their sizes and the size of their greatest common subgraph. It is proved that finding a distance between two graphs is an NP-complete problem even for planar graphs. An algorithm based on exhaustive search utilizing the linear algorithm by Hopcroft and Wong for recognizing isomorphism of planar graphs with some stopping criteria to maintain polynomial complexity, is possible.
Evaluation of spoken language systems: the ATIS domain
Authors: P. J. Price
Venue: Proceedings of the workshop on Speech and Natural Language (1990)

Progress can be measured and encouraged via standards for comparison and evaluation. Though qualitative assessments can be useful in initial stages, quantifiable measures of systems under the same conditions are essential for comparing results and assessing claims. This paper will address the emerging standards for evaluation of spoken language systems.
On the OBDD-Representation of General Boolean Functions
Authors: Heh-Tyan Liaw, Chen-Shang Lin
Venue: IEEE Transactions on Computers (1992)

The behavior of ordered binary decision diagrams (OBDD) for general Boolean functions is studied. A tight upper bound of (2/sup n//n)(2+ epsilon ) for the worst case OBDD size is derived. Although the size of an OBDD is dependent on the ordering of decision variables, it is shown that almost all functions are not sensitive to variable ordering.
Computerized Flow Field Analysis: Oriented Texture Fields
Authors: A. Ravishankar Rao, Ramesh C. Jain
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

An approach to the solution of signal-to-symbol transformation in the domain of flow fields, such as oriented texture fields and velocity vector fields, is discussed. The authors use the geometric theory of differential equations to derive a symbol set based on the visual appearance of phase portraits which are a geometric representation of the solution curves of a system of differential equations. They also provide the computational framework to start with a given flow field and derive its symbolic representation. Specifically, they segment the given texture, derive its symbolic representation, and perform a quantitative reconstruction of the salient features of the original texture based on the symbolic descriptors. Results of applying this technique to several real texture images are presented. This technique is useful in describing complex flow visualization pictures, defects in lumber processing, defects in semiconductor wafer inspection, and optical flow fields.
Semaphores for fair scheduling monitor conditions
Authors: Neil Dunstan
Venue: ACM SIGOPS Operating Systems Review (1991)

Although semaphores provide an adequate means to represent monitor condition variables, enhancements are necessary when fair scheduling is required. In this context, fair scheduling means that a process which waits on a condition is released before any subsequent processes which wait on the condition. Two solutions are shown which utilize enhanced forms of semaphores.