ppxscal/embedding_network huggingface dataset:
Efficiently counting program events with support for on-line queries
Authors: Thomas Ball
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

The ability to count events in a program's execution is required by many program analysis applications. We represent an instrumentation method for efficiently counting events in a program's execution, with support for on-line queries of the event count. Event counting differs from basic block profiling in that an aggregate count of events is kept rather than a set of counters. Due to this difference, solutions to basic block profiling are not well suited to event counting. Our algorithm finds a subset of points in a program to instrument, while guaranteeing that accurate event counts can be obtained efficiently at every point in the execution.
Urgent research issues in software process engineering
Authors: Gernot Starke
Venue: ACM SIGSOFT Software Engineering Notes (1993)

This paper outlines the major problems and research directions in software process engineering. These problems concern the terminology and language of models; the difference between type and instance; the inherent reflexivity of detailed process models and the dynamic aspects of process models. Furthermore human factors are shown to impose major difficulties on process engineers.
Integrating security in inter-domain routing protocols
Authors: Brijesh Kumar, Jon Crowcroft
Venue: ACM SIGCOMM Computer Communication Review (1993)

Network routing protocols work in a vulnerable environment. Unless protected by appropriate security measures, their operation can be easily subverted by intruders capable of modifying, deleting or adding false information in routing updates. This paper first analyses threats to the secure operation of inter-domain routing protocols, and then proposes various counter measures to make these protocols secure against external threats.
Space-efficient closure representations
Authors: Zhong Shao, Andrew W. Appel
Venue: Proceedings of the 1994 ACM conference on LISP and functional programming (1994)

Many modern compilers implement function calls (or returns) in two steps: first, a closure environment is properly installed to provide access for free variables in the target program fragment; second, the control is transferred to the target by a &ldquo;jump with arguments (or results)&rdquo;. Closure conversion, which decides where and how to represent closures at runtime, is a crucial step in compilation of functional languages. We have a new algorithm that exploits the use of compile-time control and data flow information to optimize closure representations. By extensive closure sharing and allocating as many closures in registers as possible, our new closure conversion algorithm reduces heap allocation by 36% and memory fetches for local/global variables by 43%; and improves the already-efficient code generated by the Standard ML of New Jersey compiler by about 17% on a DECstation 5000. Moreover, unlike most other approaches, our new closure allocation scheme satisfies the strong &ldquo;safe for space complexity&rdquo; rule, thus achieving good asymptotic space usage.
On "Axiomatising Finite Concurrent Processes"
Authors: Luca Aceto
Venue: SIAM Journal on Computing (1994)

In his pioneering paper [Axiomatising finite concurrent processes, SIAM J. Comput., 17 (1988), pp. 997--1017], Hennessy gave complete axiomatizations of Milner's observational congruence and of t-observational congruence which made use of an auxiliary operation to axiomatize parallel composition. Unfortunately, those axiomatizations turn out to be flawed due to the subtle interplay between Hennessy's auxiliary parallel operator and synchronization. The aim of this paper is to present correct versions of the equational characterizations given in Hennessy's paper. Some of the problems which arise in giving operational semantics to the auxiliary operators used by Bergstra and Klop and Hennessy in the theory of congruences like Milner's observational congruence are also discussed.
Efficient accommodation of may-alias information in SSA form
Authors: Ron Cytron, Reid Gershbein
Venue: ACM SIGPLAN Notices (1993)

We present an algorithm for incrementally including may-alias information into Static Single Assignment form by computing a sequence of increasingly precise (and correspondingly larger) partial SSA forms. Our experiments show significant speedup of our method over exhaustive use of may-alias information, as optimization problems converge well before most may-aliases are needed.
Path caching (extended abstract): a technique for optimal external searching
Authors: Sridhar Ramaswamy, Sairam Subramanian
Venue: Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1994)

External 2-dimensional searching is a fundamental problem with many applications in relational, object-oriented, spatial, and temporal databases. For example, interval intersection can be reduced to 2-sided, 2-dimensional searching and indexing class hierarchies of objects to 3-sided, 2-dimensional searching. Path caching is a new technique that can be used to transform a number of time/space efficient data structures for internal 2-dimensional searching (such as segment trees, interval trees, and priority search trees) into I/O efficient external ones. Let n be the size of the database, B the page size, and t the output size of a query. Using path caching, we provide the first data structure with optimal I/O query time O(logBn+t/B) for 2-sided, 2-dimensional searching. Furthermore, we show that path caching requires a small space overhead O(n&divide;Blog2log2B) and is simple enough to admit dynamic updates in optimal O(logBn) amortized time. We also extend this data structure to handle 3-sided, 2-dimensional searching with optimal I/O query-time, at the expense of slightly higher storage and update overheads.
A pragmatic approach to software synthesis
Authors: Burkhard Freitag, Tiziana Margaria, Bernhard Steffen
Venue: ACM SIGPLAN Notices (1994)

We present a practice oriented tool for software synthesis that supports the interface-correct configuration of complex systems from a library of reusable software components. Besides simply checking the interface-correctness of a link by means of type constraints, the tool is also designed to propose software components for solving a (loosely) specified problem within a certain context. In particular, it identifies possible interfacing modules that in case of an interface-conflict may serve for the right conversion, transformation or parameter configuration. We illustrate our tool, which is based on the deductive database system LOLA, in three application specific settings.
Performance of temporal reasoning systems
Authors: Ed Yampratoom, James F. Allen
Venue: ACM SIGART Bulletin (1993)

This paper describes the performance evaluation of six temporal reasoning systems. We show that if you are working with large temporal datasets where information is added incrementally throughout the execution of the program, systems using incompletely connected graphs (i.e., TMM, TimeGraph and TimeGraph-II) seem the best option. While they do not offer the constant query time of systems using fully connected graphs (i.e. the systems based on constraint satisfaction), the savings at assertion time are so substantial that the relatively small performance penalty for queries is a reasonable tradeoff. Of course, these systems do not offer the expressivity of the interval-based systems as they only handle point-based relations. Of the three, TimeGraph-II offers a wider range of qualitative relations as it handles point inequality. It does not currently handle metric information, however, as do TMM and TimeGraph. Thus decisions between these three may be more determined by the reasoning capabilities required rather than raw performance.
Integration of security in network routing protocols
Authors: Brijesh Kumar
Venue: ACM SIGSAC Review (1993)

There are two sources of threats to secure operation of routing protocols in networks. The first source of threats is subverted routers that legitimately participate in a routing protocol. The second source of threats is intruders which may illegally attempt to interfere in routing protocols by masquerading as routers. In this paper, we first analyse the security requirements of network routing protocols and then discuss the necessary measures which can be adopted to make the operation of these protocols secure.
APL helps the deaf to hear again
Authors: Pierre Deslauriers
Venue: ACM SIGAPL APL Quote Quad (1993)

This paper describes the role of APL as an efficient and crucial tool in research and development of sophisticated electronic systems. It will show how APL was successfully used in the development of a cochlear implant device. Cochlear implants are bio-medical electronic systems allowing completely deaf persons to recover partial hearing capabilities. This kind of system has been around for some time. Unfortunately, performance and flexibility have improved at a slow pace. Also, a more in-depth scientific understanding and testing were required.We will begin with an overview of the system itself, followed by the important role of APL as a time-saver and flexible tool, present some details on the APL programs and conclude with future directions for this technology.
Is designing a neural network application an art or a science?
Authors: Roman Erenshteyn, Richard Foulds, Scott Galuska
Venue: ACM SIGCHI Bulletin (1994)

Both the danger and the attraction of pattern recognition problems lie in their simplicity. When investigators first approach such a problem, they may, with an easiness which borders on carelessness, utilize the methods most familiar to them; and... they sometimes receive satisfactory results. More often, they are haunted by troubles. Only a good understanding of the problem will permit them to solve it. The quality of problem solving depends on the investigator's abilities, experience, knowledge and very often on... fertile imagination. In this paper we will discuss the problems connected with practical neural network application design.
Algebraic reasoning and completeness in typed languages
Authors: Jon G. Riecke, Ramesh Subrahmanyam
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

We consider the following problem in proving observational congruences in functional languages: given a call-by-name language based on the simply-typed &lgr;-calculus with algebraic operations axiomatized by algebraic equations E, is the set of observational congruences between terms exactly those provable from (&bgr;), (&eegr;), and E? We find conditions for determining whether &bgr;&eegr;E-equational reasoning is complete for proving the observational congruences between such terms. We demonstrate the power and generality of the theorems by presenting a number of easy corollaries for particular algebras.
Extending attribute grammars to support programming-in-the-large
Authors: Josephine Micallef, Gail E. Kaiser
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

Attribute grammars add specification of static semantic properties to context-free grammars, which, in turn, describe the syntactic structure of program units. However, context-free grammars cannot express programming-in-the-large features common in modern programming languages, including unordered collections of units, included units, and sharing of included units. We present extensions to context-free grammars, and corresponding extensions to attribute grammars, suitable for defining such features. We explain how batch and incremental attribute-evaluation algorithms can be adapted to support these extensions, resulting in a uniform approach to intraunit and interunit static semantic analysis and translation of multiunit programs.
Characterization of object behaviour in Standard ML of New Jersey
Authors: Darko Stefanovic, J. Eliot B. Moss
Venue: Proceedings of the 1994 ACM conference on LISP and functional programming (1994)

We describe a method of measuring lifetime characteristics of heap objects, and discuss ways in which such quantitative object behaviour measurements can help improve language implementations, especially garbage collection performance. For Standard ML of New Jersey, we find that certain primary aspects of object behaviour are qualitatively the same across benchmark programs, in particular the rapid object decay. We show that the heap-only allocation implementation model is the cause of this similarity. We confirm the weak generational hypothesis for SML/NJ and discuss garbage collector configuration tuning. Our approach is to obtain object statistics directly from program execution, rather than simulation, for reasons of simplicity and speed. Towards this end, we exploit the flexibility of the garbage collector toolkit as a measurement tool. Careful numerical analysis of the acquired data is necessary to arrive at relevant object lifetime measures. This study fills a gap in quantitative knowledge of the workings of heap-based compilers and their run-time systems, and should be useful to functional language implementors.
SIGKids'92
Authors: Coco Conn
Venue: ACM SIGGRAPH Computer Graphics (1993)

SIGGRAPH '92 in Chicago offered the future to a group of young students by inviting them to participate in the SIGKids '92 learning lab workshop. Computers, video, multimedia, LEGO/Logo, digital journal keeping, access to the Internet and interactive projects were explored by these bright young minds.At most education conferences, there is alot of talk about what does, could or should take place in the classroom. SIGKids went a step further. It created an ideal situation; a learning lab run by the students and their mentors. Volunteer mentors generously donated their time and skills and came from the university, industry and research communities.
Root-Locus and Boundary Feedback Design for a Class of Distributed Parameter Systems
Authors: Christopher I. Byrnes
Venue: SIAM Journal on Control and Optimization (1994)

In this paper, a fairly complete parallel of the finite-dimensional root locus theory is presented for quite general, nonconstant coefficient, even order ordinary differential operators on a finite interval with control and output boundary conditions representative of a choice of colocated point actuators and sensors. Root-locus design methods for linear distributed parameter systems have also been studied for some time and the primary difficulties in rigorously interpreting root locus conclusions for distributed parameter systems are well known. First, the transfer function of a distributed parameter system may not be meromorphic at infinity so that many of the standard Rouche arguments, required even in the lumped case to determine the asymptotic behavior of the root loci, are not generally valid. Another difficulty is that the infinitesimal generator in the state-space model for a closed-loop system may not be selfadjoint, accretive or even satisfy the spectrum determined growth condition. Thus, regardless of whether the root loci---interpreted as closed-loop eigenvalues---lie in the open left-half plane, additional analysis would be required to conclude that the closed-loop system would be asymptotically stable. Formulating the systems in the classical format of a boundary control problem, the asymptotic analysis of the root loci can be based on the pioneering work by Birkhoff on eigenfunction expansions for boundary value problems, work that predated and indeed motivated the development of spectral theory in Hilbert space. Birkhoff's work also contains an asymptotic expansion of eigenfunctions in the spatial variable, generalizing the earlier Sturm--Liouville theory for second-order operators. By further extending this general asymptotic analysis to also include expansions in the gain parameter, a rigorous treatment of the open and closed loop transfer functions and of the corresponding return difference equation can be presented. The asymptotic analysis of the return difference equation forms the basis for both our rigorous formulation of the basic problem and its solution.
A New Lower Bound Technique and its Application: Tight Lower Bound for a Polygon Triangulation
Authors: Prakash Ramanan
Venue: SIAM Journal on Computing (1994)

A new technique for obtaining lower bounds on the worst-case time-complexity of optimization problems in the linear decision tree model of computation is presented. This technique is then used to obtain a tight $\Omega(n \log n)$ lower bound for a problem of finding a minimum cost triangulation of a convex polygon with weighted vertices. This problem is similar to the problem of finding an optimal order of computing a matrix chain product. If the lower bound technique could be extended to bounded degree algebraic decision trees, a tight $\Omega(n \log n)$ lower bound for this latter problem would be obtained.
Any algorithm in the complex object algebra with powerset needs exponential space to compute transitive closure
Authors: Dan Suciu, Jan Paredaens
Venue: Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1994)

The Abiteboul and Beeri algebra for complex objects can express a query whose meaning is transitive closure, but the algorithm is naturally associated to this query needs exponential space. We show that any other query in the algebra which expresses transitive closure needs exponential space. This proves that in general the powerset is an intractable operator for implementing fixpoint queries.
An efficient implementation of multiple return values in Scheme
Authors: J. Michael Ashley, R. Kent Dybvig
Venue: Proceedings of the 1994 ACM conference on LISP and functional programming (1994)

This paper describes an implementation of the new Scheme multiple values interface. The implementation handles multiple values efficiently, with no run-time overhead for normal calls and returns. Error checks are performed where necessary to insure that the expected number of values is returned in all situations. The implementation fits cleanly with our direct-style compiler and stack-based representation of control, but is equally well suited to continuation-passing style compilers and to heap-based run-time architectures.
Examples for the algorithmic calculation of formal Puisieux, Laurent and power series
Authors: Wolfram Koepf
Venue: ACM SIGSAM Bulletin (1993)

Formal Laurent-Puisieux series (LPS) of the form [EQUATION] are important in calculus and complex analysis. In some Computer Algebra Systems (CASs) it is possible to define an LPS by direct or recursive definition of its coefficients. Since some operations cannot be directly supported within the LPS domain, some systems generally convert LPS to finite truncated LPS for operations such as addition, multiplication, division, inversion and formal substitution. This results in a substantial loss of information. Since a goal of Computer Algebra is --- in contrast to numerical programming --- to work with formal objects and preserve such symbolic information, CAS should be able to use LPS when possible.There is a one-to-one correspondence between formal power series with positive radius of convergence and corresponding analytic functions. It should be possible to automate conversion between these forms. Among CASs only MACSYMA [5] provides a procedure powerseries to calculate LPS from analytic expressions in certain special cases, but this is rather limited.In [2]-[4] we gave an algorithmic approach for computing an LPS for a very rich family of functions. It covers e.g. a high percentage of the power series that are listed in the special series dictionary [1]. The algorithm has been implemented by the author and A. Rennoch in the CAS MATHEMATICA [7], and by D. Gruntz in MAPLE [6].In this note we present some example results of our MATHEMATICA implementation which give insight in the underlying algorithmic procedure.
Nonsmooth Optimum Problems with Constraints
Authors: Zs. Pales, V. M. Zeidan
Venue: SIAM Journal on Control and Optimization (1994)

This paper develops second-order necessary conditions for nonsmooth infinite-dimensional optimization problems with Banach space-valued equality and real-valued inequality constraints. Another constraint in the form of a closed convex set is also present. The objective function is the maximum over a parameter of functions $f(t,z)$ that are Lipschitz in $z$ and upper semicontinuous in $t$. The inequality constraints $g(s,z)$ depend on a parameter $s$. The technique we use is a generalization of that of Dubovitskii and Milyutin. The second-order conditions obtained here are in terms of a certain function $\sigma$ that disappears when the parameters and a certain set that derives from the given convex set are absent. The presence of the function $\sigma$ and that set is due to the envelope-like effect discovered by Kawasaki.
An expander-based approach to geometric optimization
Authors: Matthew J. Katz, Micha Sharir
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

We present a new approach to problems in geometric optimization that are traditionally solved using the parametric searching technique of Megiddo. Our new approach is based on expander graphs and is conceptually much simpler and has more explicit geometric flavor. It does not require parallelization or randomization, and it exploits recent range-searching techniques of Matous&caron;ek and others. We exemplify the technique on three problems, the slope selection problem, the planar distance selection problem, and the planar two-center problem. For the first problem we develop an O(n log3n)) solution, which, although suboptimal, is very simple. The second and third problems are more typical examples of our approach. Our solutions have, respectively, running time O(n4/3 log3+&dgr; n), for any &dgr; > 0, and O(n2 log3 n), comparable with the respective solutions of [2, 5].
Network objects
Authors: Andrew Birrell, Greg Nelson, Susan Owicki, Edward Wobber
Venue: Proceedings of the fourteenth ACM symposium on Operating systems principles (1994)

A network object is an object whose methods can be invoked over a network. This paper describes the design, implementation, and early experience with a network objects system for Modula-3. The system is novel for its overall simplicity. The paper includes a thorough description of realistic marshaling algorithms for network objects.