ppxscal/embedding_network huggingface dataset:
MIT educators share success
Authors: John W. Belcher, R. Mark Bessette
Venue: ACM SIGGRAPH Computer Graphics (2001)

This column describes the use of computer graphics as a teaching tool. At MIT, the course Physics 8.02 has a high enrollment, but it is one of the more difficult classes for students because of the non-intuitive nature of electromagnetism. In order to properly demonstrate the phenomena, Professor John Belcher developed a series of short videos with animation and text of selected experiments. He emphasizes that "the power of animation in explaining electromagnetism can only be appreciated by viewing sample animations." You can find examples of these animations at http://web.mit.edu/jbelcher/www/anim.htmlThis article is reprinted from the SIGGRAPH 2000 Educators Program.
A mixed-signal simulator for VHDL-AMS
Authors: Xiao Liyi, Li Bin, Ye Yizheng, Huang Guoyong, Guo JinJun, Zhang Peng
Venue: Proceedings of the 2001 Asia and South Pacific Design Automation Conference (2001)

Capable and efficiency simulators are in demand for designing complex analog and mixed-signal circuits and systems. With the standardization of VHDL-AMS, the demand is being realized. VHDL-AMS is an Analog and Mixed-Signal Extensions to VHDL. This paper introduces a mixed-signal simulator for it. The simulator was developed on the original VHDL digital simulation environment. An analog kernel has been integrated into the environment for the simulation of the continuous behavior of a model. The paper presents the algorithms adopted in the analog kernel and the synchronization of the digital and analog executions. The performance of the simulator is examined by mixed-signal examples.
Algorithm 416: Rapid computation of coefficients of interpolation formulas
Authors: Sven-Åke Gustafson
Venue: Communications of the ACM (1971)

This algorithm is a companion to [1] where the theoretical background is described
Handling Obstacles in Goal-Oriented Requirements Engineering
Authors: Axel van Lamsweerde, Emmanuel Letier
Venue: IEEE Transactions on Software Engineering (2000)

Requirements engineering is concerned with the elicitation of high-level goals to be achieved by the envisioned system, the refinement of such goals and their operationalization into specifications of services and constraints and the assignment of responsibilities for the resulting requirements to agents such as humans, devices, and software. Requirements engineering processes often result in goals, requirements, and assumptions about agent behavior that are too ideal; some of them are likely not to be satisfied from time to time in the running system due to unexpected agent behavior. The lack of anticipation of exceptional behaviors results in unrealistic, unachievable, and/or incomplete requirements. As a consequence, the software developed from those requirements will not be robust enough and will inevitably result in poor performance or failures, sometimes with critical consequences on the environment. This paper presents formal techniques for reasoning about obstacles to the satisfaction of goals, requirements, and assumptions elaborated in the requirements engineering process. A first set of techniques allows obstacles to be generated systematically from goal formulations and domain properties. A second set of techniques allows resolutions to be generated once the obstacles have been identified thereby. Our techniques are based on a temporal logic formalization of goals and domain properties; they are integrated into an existing method for goal-oriented requirements elaboration with the aim of deriving more realistic, complete, and robust requirements specifications. A key principle in this paper is to handle exceptions at requirements engineering time and at the goal level, so that more freedom is left for resolving them in a satisfactory way. The various techniques proposed are illustrated and assessed in the context of a real safety-critical system.
A MATLAB differentiation matrix suite
Authors: J. A. Weideman, S. C. Reddy
Venue: ACM Transactions on Mathematical Software (TOMS) (2000)

A software suite consisting of 17 MATLAB functions for solving differential equations by the spectral collocation (i.e., pseudospectral) method is presented. It includes functions for computing derivatives of arbitrary order corresponding to Chebyshev, Hermite, Laguerre, Fourier, and sinc interpolants. Auxiliary functions are included for incorporating boundary conditions, performing interpolation using barycentric formulas, and computing roots of orthogonal polynomials. It is demonstrated how to use the package for solving eigenvalue, boundary value, and initial value problems arising in the fields of special functions, quantum mechanics, nonlinear waves, and hydrodynamic stability.
Political redistricting by computer
Authors: Robert E. Helbig, Patrick K. Orr, Robert R. Roediger
Venue: Communications of the ACM (1972)

The problems of political redistricting are considered and a computer method for redistricting is presented. Criteria for acceptable redistricting are discussed, including population equality, compactness, contiguity, and preservation of natural and/or political boundaries. Only nonpartisan criteria are considered. Using 1970 Bureau of Census population data, specific results are given for the ten Congressional Districts in the state of Missouri and for the seven St. Louis County Council seats. Results from the use of the algorithm indicate the feasibility of political redistricting with the aid of a computer.
Effects of chargeout on user/manager attitutes
Authors: Richard L. Nolan
Venue: Communications of the ACM (1977)

The relationship of internal pricing systems for computer services (chargeout systems) and user management attitudes about their computer-based information systems is investigated. Evidence is provided that the relationship conforms to a general pattern that would be expected from the hypothesis of the four stages of EDP growth [15]. The results also indicate that the chargeout systems characteristic of advanced EDP stage environments are associated with relatively high levels of positive user attitudes and marked increases in EDP training for users. Both factors are important to the user/manager involvement necessary for effective control of computer-based systems. Development and maintenance of computer-based systems is asserted to be a category of organizational change. A &ldquo;felt need&rdquo; for the change on the part of the user/manager is pre-requisite to any change taking place. The research methods of behavioral science are applied to investigate the user/manager environment and the effects of charge-out.
Towards factoring bivariate approximate polynomials
Authors: Robert M. Corless, Mark W. Giesbrecht, Mark van Hoeij, Ilias S. Kotsireas, Stephen M. Watt
Venue: Proceedings of the 2001 international symposium on Symbolic and algebraic computation (2001)

A new algorithm is presented for factoring bivariate approximate polynomials over C[x, y]. Given a particular polynomial, the method constructs a nearby composite polynomial, if one exists, and its irreducible factors. Subject to a conjecture, the time to produce the factors is polynomial in the degree of the problem. This method has been implemented in Maple, and has been demonstrated to be efficient and numerically robust.
Computer-aided diagnosis of breast lesions in medical images
Authors: Maryellen L. Giger
Venue: Computing in Science and Engineering (2000)

Given current error rates, this article surveys various approaches and techniques for improved breast lesion diagnosis in medical images, including mammography, ultrasound, and magnetic resonance imaging. The author also includes studies that compare human versus computer-aided diagnosis.
A Level Set Model for Image Classification
Authors: Christophe Samson, Laure Blanc-Féraud, Gilles Aubert, Josiane Zerubia
Venue: International Journal of Computer Vision (2000)

We present a supervised classification model based on a variational approach. This model is devoted to find an optimal partition composed of homogeneous classes with regular interfaces. The originality of the proposed approach concerns the definition of a partition by the use of level sets. Each set of regions and boundaries associated to a class is defined by a unique level set function. We use as many level sets as different classes and all these level sets are moving together thanks to forces which interact in order to get an optimal partition. We show how these forces can be defined through the minimization of a unique fonctional. The coupled Partial Differential Equations (PDE) related to the minimization of the functional are considered through a dynamical scheme. Given an initial interface set (zero level set), the different terms of the PDE's are governing the motion of interfaces such that, at convergence, we get an optimal partition as defined above. Each interface is guided by internal forces (regularity of the interface), and external ones (data term, no vacuum, no regions overlapping). Several experiments were conducted on both synthetic and real images.
Interaction patterns and observable commitments in a multi-agent trading scenario
Authors: Jeremy Pitt, Lloyd Kamara, Alexander Artikis
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

We propose a formal semantics for the protocol diagrams (interaction patterns) of AUML (Agent Unified Modelling Language). We connect this proposal with a general framework for defining the semantics of ACLs (Agent Communication Languages). We then show that protocol diagrams should be parameterised with observable commitments: additional specification of the expected outcomes and normative positions resulting from the use of the protocol. A complete axiomatisation of a contract-net protocol is given, and animated to show how the agents comply with expected replies and respecting the norms. We conclude that this approach to `socialising' interaction between agents is important for developing open agent systems and potentially useful in standardisation.
Analysis of pointer &ldquo;rotation&rdquo;
Authors: Norihisa Suzuki
Venue: Communications of the ACM (1982)

Two high-level pointer operations, rotation and slide, reduce conceptual difficulties when writing pointer programs and increase the reliability of programs. We analyze theoretically as well as empirically why these operations are more convenient and introduce a mechanically checkable notion of the safety of rotations. Several examples show that safety is a good indication of program correctness. Examples of list marking and list copying programs demonstrate the utility of these operations.
New sufficient optimality conditions for integer programming and their application
Authors: J. M. Fleisher, R. R. Meyer
Venue: Communications of the ACM (1978)

The purpose of this report is to present a new class of sufficient optimality conditions for pure and mixed integer programming problems. Some of the sets of sufficient conditions presented can be thought of as generalizations of optimality conditions based on primal-dual complementarity in linear programming. These sufficient conditions are particularly useful for the construction of difficult integer programming problems with known optimal solutions. These problems may then be used to test and/or &ldquo;benchmark&rdquo; integer programming codes.
Execution time requirements for encipherment programs
Authors: Theodore D. Friedman, Lance J. Hoffman
Venue: Communications of the ACM (1974)

Although encipherment has often been discussed as a means to protect computer data, its costs are not well established. Five experiments were conducted to measure the cpu time on a CDC 6400 required by additive ciphers programmed both in assembly language and in Fortran: a &ldquo;null transformation&rdquo; to measure the time to move data without encipherment; encipherment with a one-word key; encipherment with a 125-word key; double key encipherment; and encipherment using a pseudo random key. The results were analyzed for consistency over 100 runs, and the effects of constant and intermittent errors were considered. Timing rates for assembly language encipherment ranged from 498,800 characters per second for a pseudo random key cipher to 2,092,000 characters per second for a constant one-word key cipher. The latter is almost equivalent to the rate required simply to move data without encipherment. Fortran tests required over four times as much cpu time. This paper introduces the idea of enciphering time coefficient the ratio of enciphering time to the time taken to fetch and store data without encipherment.
A synthesis of memory mechanisms for distributed architectures
Authors: Jiajing Zhu, Jay Hoeflinger, David Padua
Venue: Proceedings of the 15th international conference on Supercomputing (2001)

Producing efficient parallel programs for distributed memory multiprocessors is a difficult task. Hand-coding efficient parallel programs for these systems can be extremely difficult, time consuming and error-prone, so people have turned to the shared memory abstraction and automatic parallelizing compilers to ease the task. The two main approaches to this are using compilers that 1) generate message passing code, or 2) generate code for a distributed shared memory software layer. Neither has been completely successful for all types of programs. In this paper, we discuss the use of a combination of these mechanisms to produce a compiler code generation paradigm that can be successful for many user programs. The experimental results indicate that our new paradigm would be able to support both regular and irregular code efficiently.
A region coloring technique for scene analysis
Authors: James P. Strong,  III, Azriel Rosenfeld
Venue: Communications of the ACM (1973)

A method of converting a picture into a &ldquo;cartoon&rdquo; or &ldquo;map&rdquo; whose regions correspond to differently textured regions is described. Texture edges in the picture are detected, and solid regions surrounded by these (usually broken) edges are &ldquo;colored in&rdquo; using a propagation process. The resulting map is cleaned by comparing the region colors with the textures of the corresponding regions in the picture, and also by merging some regions with others according to criteria based on topology and size. The method has been applied to the construction of cloud cover maps from cloud cover pictures obtained by satellites.
Universal-stability results and performance bounds for greedy contention-resolution protocols
Authors: Matthew Andrews, Baruch Awerbuch, Antonio Fernández, Tom Leighton, Zhiyong Liu, Jon Kleinberg
Venue: Journal of the ACM (JACM) (2001)

In this paper, we analyze the behavior of packet-switched communication networks in which packets arrive dynamically at the nodes and are routed in discrete time steps across the edges. We focus on a basic adversarial model of packet arrival and path determination for which the time-averaged arrival rate of packets requiring the use of any edge is limited to be less than 1. This model can reflect the behavior of connection-oriented networks with transient connections (such as ATM networks) as well as connectionless networks (such as the Internet). We concentrate on greedy (also known as work-conserving) contention-resolution protocols. A crucial issue that arises in such a setting is that of stability&mdash;will the number of packets in the system remain bounded, as the system runs for an arbitrarily long period of time? We study the universal stability of network (i.e., stability under all greedy protocols) and universal stability of protocols (i.e., stability in all networks). Once the stability of a system is granted, we focus on the two main parameters that characterize its performance: maximum queue size required and maximum end-to-end delay experienced by any packet. Among other things, we show: (i) There exist simple greedy protocols that are stable for all networks. (ii) There exist other commonly used protocols (such as FIFO) and networks (such as arrays and hypercubes) that are not stable. (iii) The n-node ring is stable for all greedy routing protocols (with maximum queue-size and packet delay that is linear in n). (iv) There exists a simple distributed randomized greedy protocol that is stable for all networks and requires only polynomial queue size and polynomial delay. Our results resolve several questions posed by Borodin et al., and provide the first examples of (i) a protocol that is stable for all networks, and (ii) a protocol that is not stable for all networks.
Does Code Decay? Assessing the Evidence from Change Management Data
Authors: Stephen G. Eick, Todd L. Graves, Alan F. Karr, J. S. Marron, Audris Mockus
Venue: IEEE Transactions on Software Engineering (2001)

A central feature of the evolution of large software systems is that change¿which is necessary to add new functionality, accommodate new hardware, and repair faults¿becomes increasingly difficult over time. In this paper, we approach this phenomenon, which we term code decay, scientifically and statistically. We define code decay and propose a number of measurements (code decay indices) on software and on the organizations that produce it, that serve as symptoms, risk factors, and predictors of decay. Using an unusually rich data set (the fifteen-plus year change history of the millions of lines of software for a telephone switching system), we find mixed, but on the whole persuasive, statistical evidence of code decay, which is corroborated by developers of the code. Suggestive indications that perfective maintenance can retard code decay are also discussed.
The weighted median filter
Authors: D. R. K. Brownrigg
Venue: Communications of the ACM (1984)

The median filter is well-known [1, 2]. However, if a user wishes to predefine a set of feature types to remove or retain, the median filter does not necessarily satisfy the requirements. A more general filter, called the Weighted Median Filter, of which the median filter is a special case, is described. It enables filters to be designed with a wide variety of properties. Particular cases of filter requirements are discussed and the corresponding filters are derived. The notion of a minimal weighted median filter, of a subclass that act identically, is introduced and discussed. The question of finding the number of distinct ways a class of filters can act is considered and solved for some classes.
Spoken content metadata and MPEG-7
Authors: J. P. A. Charlesworth, P. N. Garner
Venue: Proceedings of the 2000 ACM workshops on Multimedia (2000)

The words spoken in an audio stream form an obvious descriptor essential to most audio-visual metadata standards. When derived using automatic speech recognition systems, the spoken content fits into neither low-level (representative) nor high-level (semantic) metadata categories. This results in difficulties in creating a representation that can support both interoperability between different extraction and application utilities while retaining robustness to the limitations of the extraction process. In this paper, we discuss the issues encountered in the design of the MPEG-7 spoken content descriptor and their applicability to other metadata standards.
Classification with Nonmetric Distances: Image Retrieval and Class Representation
Authors: David W. Jacobs, Daphna Weinshall, Yoram Gdalyahu
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

One of the key problems in appearance-based vision is understanding how to use a set of labeled images to classify new images. Classification systems that can model human performance, or that use robust image matching methods, often make use of similarity judgments that are nonmetric; but when the triangle inequality is not obeyed, most existing pattern recognition techniques are not applicable. We note that exemplar-based (or nearest-neighbor) methods can be applied naturally when using a wide class of nonmetric similarity functions. The key issue, however, is to find methods for choosing good representatives of a class that accurately characterize it. We show that existing condensing techniques for finding class representatives are ill-suited to deal with nonmetric dataspaces. We then focus on developing techniques for solving this problem, emphasizing two points: First, we show that the distance between two images is not a good measure of how well one image can represent another in nonmetric spaces. Instead, we use the vector correlation between the distances from each image to other previously seen images. Second, we show that in nonmetric spaces, boundary points are less significant for capturing the structure of a class than they are in Euclidean spaces. We suggest that atypical points may be more important in describing classes. We demonstrate the importance of these ideas to learning that generalizes from experience by improving performance using both synthetic and real images. In addition, we suggest ways of applying parametric techniques to supervised learning problems that involve a specific nonmetric distance functions, showing in particular how to generalize the idea of linear discriminant functions in a way that may be more useful in nonmetric spaces.
An efficient solution to the storage correspondence problem for large sequential circuits
Authors: Wanlin Cao, Duncan M. H. Walker, Rajarshi Mukherjee
Venue: Proceedings of the 2001 Asia and South Pacific Design Automation Conference (2001)

Traditional state-traversal-based methods for verifying sequential circuits are computationally infeasible for circuits with a large number of memory elements. However, if the correspondence of the memory elements of the two circuits can be established, a difficult sequential verification problem can be transformed into an easier combinational verification problem. In this paper, we propose an approach that combines two complementary simulation-based methods for fast and accurate storage correspondence. Experiments on the large ISCAS89 benchmark circuits demonstrate the superiority.
Randomized binary searching with tree structures
Authors: Harry A. Clampett,  Jr.
Venue: Communications of the ACM (1964)

A more efficient method of using tree structures is proposed, which utilizes both plus and minus branches in the search path. Very significant gains result when the search key includes alphabetic characters.
Approximation of polygonal maps by cellular maps
Authors: George Nagy, Sharad G. Wagle
Venue: Communications of the ACM (1979)

The approximation of polygonal thematic maps by cellular maps, an important operation in geographical data processing, is analyzed. The data organization used for representing the polygonal maps is a widely used segment-based data structure, where class labels identify the regions bordering each segment on either side. The approximation algorithm presented operates on such an organization, eliminating the need for the recognition of region boundaries. Each segment is examined only once. The versatility of the new organization is further illustrated by the outline of algorithms for area computation and point inclusion. The algorithm is applied to a set of soil maps converted to computer-readable form by means of a coordinate digitizer. reachable along paths from any given node.
Gender differences in IS career choice: examine the role of attitudes and social norms in selecting IS profession
Authors: K. D. Joshi, Kristine Kuhn
Venue: Proceedings of the 2001 ACM SIGCPR conference on Computer personnel research (2001)

The proposed research will systematically assess the causes of gender-related differences in attraction to information systems (IS) as a career. We propose a Theory of Reasoned Action (TRA)&mdash;based model of intention to pursue an IS career which incorporates work value congruence, attitudes, norms, and self-efficacy. Undergraduate students in an introductory IS course, which for many will be their first introduction to the field, will be surveyed to test this model and also the extent to which their perceptions change with exposure to IS through the course.