ppxscal/embedding_network huggingface dataset:
Teaching programming to beginners - choosing the language is just the first step
Authors: Roger Duke, Eric Salzman, Jay Burmeister, Josiah Poon, Leesa Murray
Venue: Proceedings of the Australasian conference on Computing education (2000)

Over the years there has been an ongoing debate about which computer language to adopt for a first programming subject. Although some may not agree, the current consensus is that the object-oriented languages are winning the argument, and Java has increasingly become the language of choice for teaching beginners. But choosing the language is only the first step in designing a first programming subject. The adoption of an object-oriented language such as Java offers an opportunity to completely rethink our approach to teaching first-year programming, an opportunity that should not be missed. In this paper we identify what we see as the non language-specific core issues, and discuss how we approached these issues when designing and teaching a programming subject for beginners.
Application-layer mobility using SIP
Authors: Henning Schulzrinne, Elin Wedlund
Venue: ACM SIGMOBILE Mobile Computing and Communications Review (2000)

Supporting mobile Internet multimedia applications requires more than just the ability to maintain connectivity across subnet changes. We describe how the Session Initiation Protocol (SIP) can help provide terminal, personal, session and service mobility to applications ranging from Internet telephony to presence and instant messaging. We also briefly discuss application-layer mobility for streaming multimedia applications initiated by RTSP.
Pure-Mode \bi {G_{m}}−C Biquad Filters
Authors: Arie Arbel
Venue: Analog Integrated Circuits and Signal Processing (2000)

A continuous time differential voltage mode {G_{m}}&minus;C biquad and its adjoint current-mode version are described, employing FCS (floating current source) circuits as building blocks. The biquad operates in the pure mode, i.e. no resistors are used to convert internally voltage into current or vice versa. Both f_{p} and Q_{p} are tunable by current sources applied externally. The current mode version is capable of providing values of Q_{p}&sim;eq 160. Due to the increasing Loop transmission, THD improves significantly towards low frequencies. The input stage of the voltage mode version employs two OTAs, whose outputs are connected in parallel in order to add their differential inputs. This results in the hitherto unnoticed property of subtracting their common mode input, providing an open loop gain which is high for differential, but low for common mode signals.
Scheduling of outputs in grammar-based hardware synthesis of data communication protocols
Authors: J. Öberg, A. Kumar, A. Hemani
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

We present a grammar based specification method for hardware synthesis of data communication protocols in which the specification is independent of the port size. Instead, it is used during the synthesis process as a constraint. When the width of the output assignments exceed the chosen out-put port width, the assignments are split and scheduled over the available states. We present a solution to this problem and results of applying it to some relevant problems.
The selection of optimal tab settings
Authors: James L. Peterson, James R. Bitner, John H. Howard
Venue: Communications of the ACM (1978)

A new generation of computer terminals allows tab settings to be selected and set by the computer. This feature can be used to reduce the number of characters that are needed to represent a document for transmission and printing. In this note, an algorithm is given for selecting the optimal set of tab stops for minimizing the number of characters transmitted. An implementation of the algorithm has reduced the number of characters transmitted by from 7 to 30 percent, but requires a prepass through the document to compute a matrix used in determining the optimal set of tab stops. The use of fixed tab stops, as a heuristic alternative, can achieve about 80 percent of optimal with no prepass.
The duality of computation
Authors: Pierre-Louis Curien, Hugo Herbelin
Venue: Proceedings of the fifth ACM SIGPLAN international conference on Functional programming (2000)

We present the mu; -calculus, a syntax for lambda;-calculus + control operators exhibiting symmetries such as program/context and call-by-name/call-by-value. This calculus is derived from implicational Gentzen's sequent calculus LK, a key classical logical system in proof theory. Under the Curry-Howard correspondence between proofs and programs, we can see LK, or more precisely a formulation called LK mu; , as a syntax-directed system of simple types for mu; -calculus. For mu; -calculus, choosing a call-by-name or call-by-value discipline for reduction amounts to choosing one of the two possible symmetric orientations of a critical pair. Our analysis leads us to revisit the question of what is a natural syntax for call-by-value functional computation. We define a translation of lambda; mu;-calculus into mu; -calculus and two dual translations back to lambda;-calculus, and we recover known CPS translations by composing these translations.
Some negative results concerning prime number generators
Authors: Paul Pritchard
Venue: Communications of the ACM (1984)

Programs attributed to Wirth and Misra for generating the prime numbers up to a specified limit are investigated. It is shown that Wirth's program is incorrect according to three increasingly weak criteria, and a composite number is exhibited that the program accepts as prime. This is the smallest known counterexample, and could not have been found by the usual method of program testing&mdash;the program would run for trillions of years on the fastest computer before reaching it! Closely related counterexamples are given to a conjecture of Misra concerning his program. An appendix gives a particularly simple algorithmic proof of the Chinese remainder theorem.
A method based on the chi-square test for document classification
Authors: Michael Oakes, Robert Gaaizauskas, Helene Fowkes, Anna Jonsson, Vincent Wan, Micheline Beaulieu
Venue: Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval (2001)

We introduce a method for document classification based on using the chi-square test to identify characteristic vocabulary of document classes.
Physical design for FPGAs
Authors: Rajeev Jayaraman
Venue: Proceedings of the 2001 international symposium on Physical design (2001)

FPGAs have been growing at a rapid rate in the past few years. Their ever-increasing gate densities and performance capabilities are making them very popular in the design of digital systems. In this paper we discuss the state-of-the-art in FPGA physical design. Compared to physical design in traditional ASICs, FPGAs pose a different set of requirements and challenges. Consequently the algorithms in FPGA physical design have evolved differently from their ASIC counterparts. Apart from allowing FPGA users to implement their designs on FPGAs, FPGA physical design is also used extensively in developing and evaluating new FPGA architectures. Finally, the future of FPGA physical design is discussed along with how it is interacting with the latest FPGA technologies.
Data communications control procedures for the USA standard code for information interchange
Authors: E. L. Lohse
Venue: Communications of the ACM (1969)

This proposed American Standard has been accepted for publication by USA Standards Committee X3, Computers and Information Processing. In order that the final version of the proposed standard reflect the largest public consensus, X3 authorized publication of this document to elicit comment and general public reaction, with the understanding that such a working document is an intermediate result in the standardization process and is subject to change, modification, or withdrawal in part or in whole. Comments should be addressed to the X3 Secretary, Business Equipment Manufacturers Association, 235 East 42 Street, New York, NY 10017.&mdash;E. L.
LOTTERYBUS: a new high-performance communication architecture for system-on-chip designs
Authors: Kanishka Lahiri, Anand Raghunathan, Ganesh Lakshminarayana
Venue: Proceedings of the 38th annual Design Automation Conference (2001)

This paper presents Lotterybus, a novel high-performance communication architecture for system-on-chip (SoC) designs. The Lotterybus architecture was designed to address the following limitations of current communication architectures: (i) lack of control over the allocation of communication bandwidth to different system components or data flows (e.g., in static priority based shared buses), leading to starvation of lower priority components in some situations, and (ii) significant latencies resulting from variations in the time-profile of the communication requests (e.g., in time division multiplexed access (TDMA) based architectures), sometimes leading to larger latencies for high-priority communications.We present two variations of Lotterybus: the first is a low overhead architecture with statically configured parameters, while the second variant is a more sophisticated architecture, in which values of the architectural parameters are allowed to vary dynamically.Our experiments investigate the performance of the Lotterybus architecture across a wide range of communication traffic characteristics. In addition, we also analyze its performance in a 4x4 ATM switch sub-system design. The results demonstrate that the Lotterybus architecture is (i) capable of providing the designer with fine grained control over the bandwidth allocated to each SoC component or data flow, and (ii) well suited to provide high priority communication traffic with low latencies (we observed upto 85.4\% reduction in communication latencies over conventional on-chip communication architectures).
Zyklodeon: a software construction kit modeling cyclic timing patterns
Authors: Carol Strohecker, A. H. Slaughter, M. A. Horvath, N. J. Appleton
Venue: Proceedings of the 2000 ACM workshops on Multimedia (2000)

Zyklodeon is a software construction kit in which Players create colorful Dancers and set them into motion. Dancers' appearances are inspired by Picasso's post-Cubist works, and movements are inspired by Martha Graham's emphasis on the torso as life center. The figures breathe visibly and move gracefully as they encounter other Dancers. Zyklodeon Players construct the figures and set parameters for their movements, thus experimenting with time cycles and notions of emergence in dynamic systems. Our design challenge is to make such complex relationships accessible through coordination of image and sound. We illustrate Dancers' movements as well as measures for breathing and dancing cycles. Graphical communication of key moments in the cycles is augmented by triggering of sounds that combine to form lively music.
Automatic graders for programming classes
Authors: Jack Hollingsworth
Venue: Communications of the ACM (1960)

Fifteen months ago the first version of an &ldquo;automatic grader&rdquo; was tried with a group of twenty students taking a formal course in programming. The first group of twenty programs took only five minutes on the computer (an IBM 650). With such a satisfactory beginning, the grader was then used for the entire course with this group of students and have been used at Rensselaer ever since. For all exercises, the average time spent on the computer has run from half a minute to a minute for each student. In general only an eighth as much computer time is required when the grader is used as is required when each student is expected to run his own program, probably less than a third as much staff time, and considerably less student time. The grader easily justifies itself on economic grounds. It accomplishes more than savings in time and money; it makes possible the teaching of programming to large numbers of students. This spring we had 80 students taking a full semester course in programming; over 120 are expected next spring. We could not accommodate such numbers without the use of the grader. Even though the grader makes the teaching of programming to large numbers of students possible and economically feasible, a most serious question remains, how well did the students learn? After fifteen months, our experience leads us to believe that students learn programming not only as well but probably better than they did under the method we did use&mdash;laboratory groups of four or five students. They are not as skilled in machine operation, however, since they get only a brief introduction to it late in the course. After learning programming, very little time is needed for each student to become at least an adequate machine operator. Students seem to like the grader and are not reluctant to suggest improvements!
Strongly equivalent logic programs
Authors: Vladimir Lifschitz, David Pearce, Agustín Valverde
Venue: ACM Transactions on Computational Logic (TOCL) (2001)

A logic program P1 is said to be equivalent to a logic program P2 in the sense of the answer set semantics if P1 and P2 have the same answer sets. We are interested in the following stronger condition: for every logic program, P, P1, &cup; P has the same answer sets as P2 &cup; P. The study of strong equivalence is important, because we learn from it how one can simplify a part of a logic program without looking at the rest of it. The main theorem shows that the verification of strong equivalence can be accomplished by cheching the equivalence of formulas in a monotonic logic, called the logic of here-and-there, which is intermediate between classical logic and intuitionistic logic.
Spatio-temporal representation and retrieval using moving object's trajectories
Authors: Choon-Bo Shim, Jae-Woo Chang
Venue: Proceedings of the 2000 ACM workshops on Multimedia (2000)

In this paper, we propose a new spatio-temporal representation scheme using moving objects' trajectories in video data. In order to support content-based retrieval on video data very well, our representation scheme considers the moving distance of an object during a given time interval as well as its temporal and spatial relations. Based on our representation scheme, we present a new similarity measure algorithms for the trajectory of moving objects, which provides ranking for the retrieved video results. Finally, we show from our experiment that our representation scheme achieves about 20% higher precision while holding about the same recall, compared with Li's and Shan's schemes.
Pracniques: coordinated text and tranperiences
Authors: R. W. Bemer
Venue: Communications of the ACM (1983)

An economical method of producing both hard copy and projection forms of text, without duplication of effort.
Striping in disk array RM2 enabling the tolerance of double disk failures
Authors: Chan-Ik Park, Tae-Young Choe
Venue: Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) (1996)

There is a growing demand in high reliability beyond what current RAID can provide and there are various levels of user demand for data reliability. An efficient data placement scheme called RM2 has been proposed in \cite{Park95}, which makes a disk array system tolerable against double disk failures. In this paper, we consider how to choose an optimal striping unit for RM2 particularly when no workload information is available except read/write ratio. A disk array simulator for RM2 has been developed for experimental works. It is shown that RM 2 has an optimal striping unit of two and half tracks in the case of disk read operations, and one third of a single track if any disk write operations are involved.
The implementation of MPI-2 one-sided communication for the NEC SX-5
Authors: Jesper Larsson Traff, Hubert Ritzdorf, Rolf Hempel
Venue: Proceedings of the 2000 ACM/IEEE conference on Supercomputing (CDROM) (2000)

We describe the MPI/SX implementation of the MPI-2 standard for one-sided communication (Remote Memory Access) for the NEC SX-5 vector supercomputer. MPI/SX is a non-threaded implementation of the full MPI-2 standard. Essential features of the implementation are presented, including the synchronization mechanisms, the handling of communication windows in global shared and in process local memory, as well as the handling of MPI derived data types. In comparative benchmarks the data transfer operations for one-sided communication and point-to-point message passing show very similar performance, both when data reside in global shared and when in process local memory. Derived data types, which are of particular importance for applications using one-sided communications, impose only a modest overhead and can be used without any significant loss of performance. Thus, the MPI/SX programmer can freely choose either the message passing or the one-sided communication model, whichever is most convenient for the given application.
Output Guards and Nondeterminism in &ldquo;Communicating Sequential Processes&rdquo;
Authors: Arthur Bernstein
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1980)

In a recent paper C.A.R. Hoare outlined a language for concurrent programming. Guarded commands and nondeterminism are two features of the language. This paper points out two problems that arise in connection with these features and addresses one of them.
ACL: a language specific for auditors
Authors: H. J. Will
Venue: Communications of the ACM (1983)

Audit software is essential for accountants. The software should be written to consolidate the audit support functions into a common language for management information systems (MIS). ACL (Audit Command Language) is a prototype language for designing a feasible interactive conversational language for auditing purposes.
Integrating active information delivery and reuse repository systems
Authors: Yunwen Ye, Gerhard Fischer, Brent Reeves
Venue: ACM SIGSOFT Software Engineering Notes (2000)

Although software reuse can improve both the quality and productivity of software development, it will not do so until software developers stop believing that it is not worth their effort to find a component matching their current problem. In addition, if the developers do not anticipate the existence of a given component, they will not even make an effort to find it in the first place. Even the most sophisticated and powerful reuse repositories will not be effective if developers don't anticipate a certain component exists, or don't deem it worthwhile to seek for it. We argue that this crucial barrier to reuse is overcome by integrating active information delivery, which presents information without explicit queries from the user, and reuse repository systems. A prototype system, CodeBroker, illustrates this integration and raises several issues related to software reuse.
Two-Way Ambiguity in 2D Projective Reconstruction from Three Uncalibrated 1D Images
Authors: Long Quan
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2001)

We show that there is, in general, a two-way ambiguity for 2D projective reconstruction from three uncalibrated 1D views, independent of the number of point correspondences. The two distinct projective reconstructions are exactly related by a quadratic transformation with the three camera centers as fundamental points. Unique 2D reconstruction is possible only when the three camera centers are aligned. By Carlsson duality, there is a dual two-way ambiguity for 2D projective reconstruction from six point correspondences, independent of the number of 1D views. The theoretical results are demonstrated on numerical examples.
Retrieval&mdash;Update speed tradeoffs using combined indices
Authors: James K. Mullin
Venue: Communications of the ACM (1971)

In a paper in the November 1970 Communications of the ACM, V.Y. Lum introduced a technique of file indexing named combined indices. This technique permitted decreased retrieval time at the cost of increased storage space. This paper examines combined indices under conditions of file usage with different fractions of retrieval and update. Tradeoff curves are developed to show minimal cost of file usage by grouping various partially combined indices.
Analysis of a cone-based distributed topology control algorithm for wireless multi-hop networks
Authors: Li Li, Joseph Y. Halpern, Paramvir Bahl, Yi-Min Wang, Roger Wattenhofer
Venue: Proceedings of the twentieth annual ACM symposium on Principles of distributed computing (2001)

The topology of a wireless multi-hop network can be controlled by varying the transmission power at each node. In this paper, we give a detailed analysis of a cone-based distributed topology control algorithm. This algorithm, introduced in [16], does not assume that nodes have GPS information available; rather it depends only on directional information. Roughly speaking, the basic idea of the algorithm is that a node u transmits with the minimum power pu, &agr; required to ensure that in every cone of degree &agr; around u, there is some node that u can reach with power pu, &agr;. We show that taking &agr; = 5&pgr;/6 is a necessary and sufficient condition to guarantee that network connectivity is preserved. More precisely, if there is a path from s to t when every node communicates at maximum power then, if &agr; &lne; 5&pgr;/6, there is still a path in the smallest symmetric graph G&agr; containing all edges (u, v) such that u can communicate with v using power pu, &agr;. On the other hand, if &agr; > 5&pgr;/6, connectivity is not necessarily preserved. We also propose a set of optimizations that further reduce power consumption and prove that they retain network connectivity. Dynamic reconfiguration in the presence of failures and mobility is also discussed. Simulation results are presented to demonstrate the effectiveness of the algorithm and the optimizations.
A new method for determining linear precedence functions for precedence grammars
Authors: James R. Bell
Venue: Communications of the ACM (1969)

The precedence relations of a precedence grammar can be precisely described by a two-dimensional precedence matrix. Often the information in the matrix can be represented more concisely by a pair of vectors, called linear precedence functions. A new algorithm is presented for obtaining the linear precedence functions when given the precedence matrix; this algorithm is shown to possess several computational adavantages.
Generating well-shaped Delaunay meshed in 3D
Authors: Xiang-Yang Li, Shang-Hua Teng
Venue: Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms (2001)

A triangular mesh in 3D is a decomposition of a given geometric domain into tetrahedra. The mesh is well-shaped if the aspect ratio of every of its tetrahedra is bounded from above by a constant. It is Delaunay if the interior of the circum-sphere of each of its tetrahedra does not contain any other mesh vertices. Generating a well-shaped Delaunay mesh for any 3D domain has been a long term outstanding problem. In this paper, we present an efficient 3D Delaunay meshing algorithm that mathematically guarantees the well-shape quality of the mesh, if the domain does not have acute angles. The main ingredient of our algorithm is a novel refinement technique which systematically forbids the formation of shivers, a family of bad elements that none of the previous known algorithms can cleanly remove, especially near the domain boundary &mdash; needless to say, that our algorithm ensure that there is no sliver near the boundary of the domain.