ppxscal/embedding_network huggingface dataset:
Intersection types and computational effects
Authors: Rowan Davies, Frank Pfenning
Venue: Proceedings of the fifth ACM SIGPLAN international conference on Functional programming (2000)

We show that standard formulations of intersection type systems are unsound in the presence of computational effects, and propose a solution similar to the value restriction for polymorphism adopted in the revised definition of Standard ML. It differs in that it is not tied to let-expressions and requires an additional weakening of the usual subtyping rules. We also present a bi-directional type-checking algorithm for the resulting language that does not require an excessive amount of type annotations and illustrate it through some examples. We further show that the type assignment system can be extended to incorporate parametric polymorphism. Taken together, we see our system and associated type-checking algorithm as a significant step towards the introduction of intersection types into realistic programming languages. The added expressive power would allow many more properties of programs to be stated by the programmer and statically verified by a compiler.
A Comment on 'Graph-Based Algorithm for Boolean Function Manipulation'
Authors: Elena Dubrova, Luca Macchiarulo
Venue: IEEE Transactions on Computers (2000)

In this paper, a slight error in the paper of Bryant [1] is corrected. It was stated in [1] that, under a certain ordering restriction, composition of two Reduced Ordered Binary Decision Diagrams (ROBDDs) results in a reduced OBDD. We show a counterexample and explore under which conditions this statement is incorrect.
Scan line methods for displaying parametrically defined surfaces
Authors: Jeffrey M. Lane, Loren C. Carpenter, Turner Whitted, James F. Blinn
Venue: Communications of the ACM (1980)

This paper presents three scan line methods for drawing pictures of parametrically defined surfaces. A scan line algorithm is characterized by the order in which it generates the picture elements of the image. These are generated left to right, top to bottom in much the same way as a picture is scanned out on a TV screen. Parametrically defined surfaces are those generated by a set of bivariate functions defining the X, Y, and Z position of points on the surface. The primary driving mechanism behind such an algorithm is the inversion of the functions used to define the surface. In this paper, three different methods for doing the numerical inversion are presented along with an overview of scan line methods.
Public Sector Hospital Efficiency for Provincial Markets in Turkey
Authors: Ismet Sahin, Yasar A. Ozcan
Venue: Journal of Medical Systems (2000)

This study uses Data Envelopment Analysis to examine public sector hospital efficiency in 80 provincial markets in Turkey. Outputs of the study includes mortality rate as quality measure as well as inpatient discharges and outpatient visits. Patient beds, four levels of health labor, and expenditures are used to capture capital, labor and material resources as inputs. Results show that 55% of the public hospitals in served markets are operated inefficiently. Analysis of inefficient provinces suggests that in those 44 inefficient provinces are collectively overbedded, employ excessive number of specialists and other health labor. They spent approximately $70,000,000 from their revolving funds in excess compared to efficient provinces.
Parallelism in tape-sorting
Authors: Shimon Even
Venue: Communications of the ACM (1974)

Two methods for employing parallelism in tape-sorting are presented. Method A is the natural way to use parallelism. Method B is new. Both approximately achieve the goal of reducing the processing time by a divisor which is the number of processors.
A method of bivariate interpolation and smooth surface fitting based on local procedures
Authors: Hiroshi Akima
Venue: Communications of the ACM (1974)

A method is designed for interpolating values given at points of a rectangular grid in a plane by a smooth bivariate function z = z(x, y). The interpolating function is a bicubic polynomial in each cell of the rectangular grid. Emphasis is on avoiding excessive undulation between given grid points. The proposed method is an extension of the method of univariate interpolation developed earlier by the author and is likewise based on local procedures.
AMTree: an active approach to multicasting in mobile networks
Authors: Kwan-Wu Chin, Mohan Kumar
Venue: Mobile Networks and Applications (2001)

Active networks (ANs) are a new paradigm in computer networking. In ANs, programs can be injected into routers and switches to extend the functionalities of the network. This allows programmers to enhance existing protocols and enables the rapid deploymentof new protocols. Little work has been done in the area of multicast routing in heterogeneous environments. In this paper, we propose AMTree, an AN-based multicast tree that is bidirectional, optimizable on demand and adaptive to source migration. We show how ANs can be exploited to enable multicast tree to be modified and optimized efficiently. By filtering unnecessary signaling messages, maintaining minimal storage at routers and incorporating features from shared-tree methods we are able to achieve a scalable solution. Furthermore, we introduce an AN-based optimisation algorithm that is executed on demand by receivers. Besides that we introduce a fast rejoin protocol for receiver migration that makes no assumptions about the existence of multicast services in foreign networks. The performance of AMTree is compared to those of the bidirectional home agent (HA) method and the remote subscription method. We found that compared to the bidirectional HA method AMTree has a much lower handoff and end-to-end latency. Unlike the bidirectional HA method where end-to-end latency increases as the mobile host (MH) migrates further away from its HA, AMTree's latency remains fairly constant. We found that after optimization, the resulting tree's end-to-end latency to be comparable to the remote subscription method but without the need for building a new multicast tree after each handoff.
A survey of attitudes toward computers
Authors: Perry R. Morrison
Venue: Communications of the ACM (1983)

What do people really think about computers and their impact? In 1970, a study of people's attitudes in North America showed computers to be regarded as either &ldquo;beneficial tools of mankind&rdquo; or as &ldquo;awesome thinking machines.&rdquo; A recent survey taken in Australia and reported in this article, though, suggests there may have been a change in attitudes over the past decade. The Australians expressed much concern over the computer's possible disemploying and dehumanizing effects&mdash;as well as disquiet over the control computers could exercise over their lives. If these attitudes are typical beyond the shores of Australia, they could create a barrier to the widespread acceptance and application of computers around the world.
Representations for space planning
Authors: Charles M. Eastman
Venue: Communications of the ACM (1970)

Problems involving the arrangement of objects in two- or three-space where the objective function primarily consists of derivatives of the distance between objects or their arrangement are called space planning problems. The representational requirements for this problem area are defined and compared with current computer graphic languages. Four alternative data structures that allow automated space planning are described and compared.
Satisfaction of IT professionals with employment arrangements in traditional and virtual contexts
Authors: Thomas W. Ferratt, Harvey G. Enns, Jayesh Prasad
Venue: Proceedings of the 2001 ACM SIGCPR conference on Computer personnel research (2001)

Retention of IT personnel is a difficulty encountered by many organizations today, particularly for those who work in virtual organization contexts. However, the fit between IT employees' preferred work arrangements and their current work arrangements and this fit's impact on IT employees' intention to stay has been an under-researched phenomenon. This paper develops a conceptual framework, based on Rousseau's [38] psychological contract theory, to address the retention concern. Additional literatures that enhance the conceptual framework suggest that the antecedents of fit, besides preferred employment arrangement, include IT employee stages and anchors, IT competencies, and organizational factors, including IT human resource practices. IT human resource strategy, in turn, impacts the organizational factors. The conceptual framework incorporates additional antecedents of intention to stay, including other employment opportunities, virtual team factors, and individual factors. The paper also suggests an initial empirical study to explore the concept of fit and its antecedents as an initial point of departure for the examination of the conceptual model.
Topic segmentation of news speech using word similarity
Authors: Seiichi Takao, Jun Ogata, Yasuo Ariki
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

Conventional topic segmentation utilizes cosine measure as the similarity between consecutive passages. However, the cosine measure has a problem that it can not reflect the similarity unless exactly the same words are included in the passages. To solve this problem, in this paper, we propose a method to acquire the word similarity between different words from the input data directly and automatically by managing to collect the same topic sections. Further more, we propose a method to compute the passage similarity based on the word similarity. Finally we propose a method of topic segmentation based on the passage similarity in an unsupervised mode.
SAFKASI: a security mechanism for language-based systems
Authors: Dan S. Wallach, Andrew W. Appel, Edward W. Felten
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (2000)

In order to run untrusted code in the same process as trusted code, there must be a mechanism to allow dangerous calls to determine if their caller is authorized to exercise the privilege of using the dangerous routine. Java systems have adopted a technique called stack inspection to address this concern. But its original definition, in terms of searching stack frames, had an unclear relationship to the actual achievement of security, overconstrained the implementation of a Java system, limited many desirable optimizations such as method inlining and tail recursion, and generally interfered with interprocedural optimization. We present a new semantics for stack inspection based on a belief logic and its implementation using the calculus of security-passing style which addresses the concerns of traditional stack inspection. With security-passing style, we can efficiently represent the security context for any method activation, and we can build a new implementation strictly by rewriting the Java bytecodes before they are loaded by the system. No changes to the JVM or bytecode semantics are necessary. With a combination of static analysis and runtime optimizations, our prototype implementation showes reasonable performance (although traditional stack inspection is still faster), and is easier to consider for languages beyond Java. We call our system SAFKASI (the Security Architecture Formerly Known as Stack Inspection).
Constraint-Based Sensor Planning for Scene Modeling
Authors: Michael K. Reed, Peter K. Allen
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

We describe an automated scene modeling system that consists of two components operating in an interleaved fashion: an incremental modeler that builds solid models from range imagery and a sensor planner that analyzes the resulting model and computes the next sensor position. This planning component is target-driven and computes sensor positions using model information about the imaged surfaces and the unexplored space in a scene. The method is shape-independent and uses a continuous-space representation that preserves the accuracy of sensed data. It is able to completely acquire a scene by repeatedly planning sensor positions, utilizing a partial model to determine volumes of visibility for contiguous areas of unexplored scene. These visibility volumes are combined with sensor placement constraints to compute sets of occlusion-free sensor positions that are guaranteed to improve the quality of the model. We show results for the acquisition of a scene that includes multiple, distinct objects with high occlusion.
From algorithms to hardware architectures: a comparison of regular and irregular structured IDCT algorithms
Authors: C. Schneider, M. Kayss, T. Hollstein, J. Deicke
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

The inverse discrete cosine transformation (IDCT) is used in a variety of decoders (e.g. MPEG). On one hand, highly optimized algorithms that are characterized by an irregular structure and a minimum number of operations are known from software implementations. On the other hand, regular structured architectures are often used in hardware realizations. In this paper a comparison of regular and irregular structured IDCT algorithms for efficient hardware realization is presented. The irregular structured algorithms are discussed with main emphasis on assessment criteria for algorithm selection and high-level synthesis for hardware cost estimation.
Remote access to clinical data
Authors: Andy Schneider
Venue: Addendum to the 2000 proceedings of the conference on Object-oriented programming, systems, languages, and applications (Addendum) (2000)

This practitioner report focuses on a project, named &ldquo;Remote Access to Clinical Data&rdquo; (RACD). The report describes the techniques used to clarify the requirements and deliver the project successfully. In addition, it covers the team's experiences in using Sun's JINI to provide a robust distributed infrastructure for RACD. The presentation will cover these areas in equal depth.
Dynamic data distribution with control flow analysis
Authors: Jordi Garcia, Eduard Ayguade, Jesus Labarta
Venue: Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) (1996)

This paper describes the design of a data distribution tool which automatically derives the data mapping for the arrays and the parallelization strategy for the loops in a Fortran 77 program. The layout generated can be static or dynamic, and the distribution is one-dimensional BLOCK or CYCLIC. The tool takes into account the control flow statements in the code in order to better estimate the behavior of the program. All the information regarding data movement and parallelism is contained in a single data structure named Communication-Parallelism Graph (CPG). The CPG is used to model a minimal path problem in which time is the objective function to minimize. It is solved using a general purpose linear programming solver, which finds the optimal solution for the whole problem. The experimental results will illustrate the quality of the solutions generated and the feasibility of the approach in terms of compilation time.
Nonlinear extrapolation and two-point boundary value problems
Authors: Richard Bellman, Harriet Kagiwada, Robert Kalaba
Venue: Communications of the ACM (1965)

It is suggested that the convergence properties of the usual Picard successive approximation scheme may be improved through use of nonlinear extrapolation techniques. A numerical example is provided.
Numerical Analysis: Numerical solution of a thin plate heat transfer problem
Authors: G. W. Stewart,  III, Dale W. Lick
Venue: Communications of the ACM (1968)

The numerical solution of a system of linear equations resulting from a discrete approximation to a thin plate heat transfer problem is considered. The slow convergence of point iterative methods is analyzed and shown to be caused by one of the boundary conditions. The difficulty may be removed by a standard line iterative technique.
Architectural rule checking for high-level synthesis
Authors: J. Gong, C.-T. Chen, K. Kücükcakar
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

Verifying an implementation produced from high-level synthesis is a challenging problem due to many complex design tasks involved in the design process. In this paper, we present an architectural rule checking approach for high-level design verification. This technique detects and locates various design errors and verifies both the consistency and correctness of an implementation. Besides describing different rule suites, we also report a working environment for the architectural rule checking. Finally, we highlight the value of the proposed approach with a real-life design.
The Story of OpenAL
Authors: Bernd Kreimeier
Venue: Linux Journal (2001)

Kreimeier explores one of Loki's free software projects.
Using Postfix for Secure SMTP Gateways
Authors: Mick Bauer, Brenno de Winter
Venue: Linux Journal (2000)

Improve your site's e-mail hygiene and make life difficult for spammers and hackers.
Perfect hashing functions: a single probe retrieving method for static sets
Authors: Renzo Sprugnoli
Venue: Communications of the ACM (1977)

A refinement of hashing which allows retrieval of an item in a static table with a single probe is considered. Given a set I of identifiers, two methods are presented for building, in a mechanical way, perfect hashing functions, i.e. functions transforming the elements of I into unique addresses. The first method, the &ldquo;quotient reduction&rdquo; method, is shown to be complete in the sense that for every set I the smallest table in which the elements of I can be stored and from which they can be retrieved by using a perfect hashing function constructed by this method can be found. However, for nonuniformly distributed sets, this method can give rather sparse tables. The second method, the &ldquo;remainder reduction&rdquo; method, is not complete in the above sense, but it seems to give minimal (or almost minimal) tables for every kind of set. The two techniques are applicable directly to small sets. Some methods to extend these results to larger sets are also presented. A rough comparison with ordinary hashing is given which shows that this method can be used conveniently in several practical applications.
Nonlinear Matrix Iterative Processes and Generalized Coefficients of Ergodicity
Authors: Marc Artzrouni, Olivier Gavart
Venue: SIAM Journal on Matrix Analysis and Applications (2000)

A nonlinear matrix iterative process is a linear dynamical system for which there is a nonlinear feedback of the current vector on the entries of the matrix. Stability conditions for an asymptotically exponential solution are studied for such a process in the positive quadrant of $\mathbb{R}^{n}.$ The results hinge on a generalization of the coefficient of ergodicity of a nonnegative matrix.
Performance guarantee for online deadline scheduling in the presence of overload
Authors: Tak-Wah Lam, Kar-Keung To
Venue: Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms (2001)

Earliest deadline first (EDF) is a widely-used online algorithm for scheduling jobs with deadlines in real-time systems. Yet, existing results on the performance guarantee of EDF are limited to underloaded systems [6,12,14]. This paper initiates the study of EDF for overloaded systems, attaining similar performance guarantees as in the underloaded setting. Specifically, we show that EDF with a simple form of admission control is optimal for scheduling on both uniprocessor and multiprocessors when moderately faster processors are available (our analysis actually admits a tradeoff between speed and extra processors). This is the first result attaining optimality under overload. Another contribution of this paper is an improved analysis of the competitiveness for weighted deadline scheduling.
A model for verification of data security in operating systems
Authors: Gerald J. Popek, David A. Farber
Venue: Communications of the ACM (1978)

Program verification applied to kernel architectures forms a promising method for providing uncircumventably secure, shared computer systems. A precise definition of data security is developed here in terms of a general model for operating systems. This model is suitable as a basis for verifying many of those properties of an operating system which are necessary to assure reliable enforcement of security. The application of this approach to the UCLA secure operating system is also discussed.
Linux System Administration : A User's Guide
Authors: Marcel Gagne
Venue: Linux Journal (2000)

An excerpt from our French chef's upcoming book.
Redundant Constant-Factor Implementation of Multi-Dimensional CORDIC andIts Application to Complex SVD
Authors: Shen-Fu Hsiao, Chun-Yi Lau, Jean-Marc Delosme
Venue: Journal of VLSI Signal Processing Systems (2000)

Redundant Implementations of Multi-dimensional CORDIC algorithms are presented where the carry-ripple additions are replaced by carry-free signed-digit additions. Both folded (iterative) and unfolded (pipelined) architectures are considered in the redundant implementation. Furthermore, the scaling iterations are merged with the unscaled CORDIC iterations in the folded CORDIC architecture in order to reduce the overall computation time of one CORDIC operation. The redundant multidimensional CORDIC is then applied to the singular value decomposition of complex matrices, with either a folded or an on-line architecture. The resulting processing speed is higher than with alternative approaches based on 2-D CORDIC.
Wengert's numerical method for partial derivatives, orbit determination and quasilinearization
Authors: R. E. Bellman, H. Kagiwada, R. E. Kalaba
Venue: Communications of the ACM (1965)

In a recent article in the Communications of the ACM, R. Wengert suggested a technique for machine evaluation of the partial derivatives of a function given in analytical form. In solving nonlinear boundary-value problems using quasilinearization many partial derivatives must be formed analytically and then evaluated numerically. Wengert's method appears very attractive from the programming viewpoint and permits the treatment of large systems of differential equations which might not otherwise be undertaken.
Incremental physical design
Authors: J. Cong, M. Sarrafzadeh
Venue: Proceedings of the 2000 international conference on Computer-aided design (2001)

Incremental modification and optimization in VLSI Computer-Aided Design (CAD) is of fundamental importance. However, it has not been investigated as a discipline. Previous research and development effort is very unfocused and incomplete. Comprehensive study of incremental algorithms and solutions in the context of CAD tool development is an open area of research with a great deal of potential. Full understanding and focused participation in research and development in the area of incremental and dynamic would help us cope with the complexity of present day VLSI systems and facilitates concurrent optimization. In this paper we formulate and survey fundamental problems in incremental physical design. Preliminary solutions to a subset of these problems will be outlined.
A new method for the solution of the Cauchy problem for parabolic equations
Authors: John Moore, Prentiss Robinson
Venue: Communications of the ACM (1972)

partial differential equations. When the equations are defined in unbounded domains, as in the initial value (Cauchy) problem, the solution of the integral equation by the method of successive approximation has inherent advantages over other methods. Error bounds for the method are of order h3/2 and h7/2 (h is the increment size) depending on the finite difference approximations involved.
Algorithm 415: Algorithm for the assignment problem (rectangular matrices)
Authors: F. Bourgeois, J. C. Lassalle
Venue: Communications of the ACM (1971)

This algorithm is a companion to [3] where the theoretical background is described.