ppxscal/embedding_network huggingface dataset:
Genre ecologies: an open-system approach to understanding and constructing documentation
Authors: Clay Spinuzzi, Mark Zachry
Venue: ACM Journal of Computer Documentation (JCD) (2000)

Arguing that current approaches to understanding and constructing computer documentation are based on the flawed assumption that documentation works as a closed system, the authors present an alternative way of thinking about the texts that make computer technologies usable for people. Using two historical case studies, the authors describe how a genre ecologies framework provides new insights into the complex ways that people use texts to make sense of computer technologies. The framework is designed to help researchers and documentors account for contingency, decentralization, and stability in the multiple texts the people use while working with computers. The authors conclude by proposing three heuristic tools to support the work of technical communicators engaged in developing documentation today: exploratory questions, genre ecology diagrams, and organic engineering.
Example-based hinting of true type fonts
Authors: Douglas E. Zongker, Geraldine Wade, David H. Salesin
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

Hinting in TrueType is a time-consuming manual process in which a typographer creates a sequence of instructions for better fitting the characters of a font to a grid of pixels. In this paper, we propose a new method for automatically hinting TrueType fonts by transferring hints of one font to another. Given a hinted source font and a target font without hints, our method matches the outlines of corresponding glyphs in each font, and then translates all of the individual hints for each glyph from the source to the target font. It also translates the control value table (CVT) entries, which are used to unify feature sizes across a font. The resulting hinted font already provides a great improvement over the unhinted version. More importantly, the translated hints, which preserve the sound, hand-designed hinting structure of the original font, provide a very good starting point for a professional typographer to complete and fine-tune, saving time and increasing productivity. We demonstrate our approach with examples of automatically hinted fonts at typical display sizes and screen resolutions. We also provide estimates of the time saved by a professional typographer in hinting new fonts using this semi-automatic approach.
Two methods for display of high contrast images
Authors: Jack Tumblin, Jessica K. Hodgins, Brian K. Guenter
Venue: ACM Transactions on Graphics (TOG) (1999)

High contrast images are common in night scenes and other scenes that include dark shadows and bright light sources. These scenes are difficult to display because their contrasts greatly exceed the range of most display devices for images. As a result, the image constrasts are compressed or truncated, obscuring subtle textures and details. Humans view and understand high contrast scenes easily, &ldquo;adapting&rdquo; their visual response to avoid compression or truncation with no apparent loss of detail. By imitating some of these visual adaptation processes, we developed methods for the improved display of high-contrast images. The first builds a display image from several layers of lighting and surface properties. Only the lighting layers are compressed, drastically reducing contrast while preserving much of the image detail. This method is practical only for synthetic images where the layers can be retained from the rendering process. The second method interactively adjusts the displayed image to preserve local contrasts in a small &ldquo;foveal&rdquo; neighborhood. Unlike the first method, this technique is usable on any image and includes a new tone reproduction operator. Both methods use a sigmoid function for contrast compression. This function has no effect when applied to small signals but compresses large signals to fit within an asymptotic limit. We demonstrate the effectiveness of these approaches by comparing processed and unprocessed images.
Improved Generalization Through Explicit Optimization of Margins
Authors: Llew Mason, Peter L. Bartlett, Jonathan Baxter
Venue: Machine Learning (2000)

Recent theoretical results have shown that the generalization performance of thresholded convex combinations of base classifiers is greatly improved if the underlying convex combination has large margins on the training data (i.e., correct examples are classified well away from the decision boundary). Neural network algorithms and AdaBoost have been shown to implicitly maximize margins, thus providing some theoretical justification for their remarkably good generalization performance. In this paper we are concerned with maximizing the margin explicitly. In particular, we prove a theorem bounding the generalization performance of convex combinations in terms of general cost functions of the margin, in contrast to previous results, which were stated in terms of the particular cost function sgn(&thetas; &minus; margin). We then present a new algorithm, DOOM, for directly optimizing a piecewise-linear family of cost functions satisfying the conditions of the theorem. Experiments on several of the datasets in the UC Irvine database are presented in which AdaBoost was used to generate a set of base classifiers and then DOOM was used to find the optimal convex combination of those classifiers. In all but one case the convex combination generated by DOOM had lower test error than AdaBoost's combination. In many cases DOOM achieves these lower test errors by sacrificing training error, in the interests of reducing the new cost function. In our experiments the margin plots suggest that the size of the minimum margin is not the critical factor in determining generalization performance.
Manual and cognitive benefits of two-handed input: an experimental study
Authors: Andrea Leganchuk
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (1998)

One of the recent trends in computer input is to utilize users' natural bimanual motor skills. This article further explores the potential benefits of such two-handed input. We have observed that bimanual manipulation may bring two types of advantages to human-computer interaction: manual and cognitive. Manual benefits come from increased time-motion efficiency, due to the twice as many degrees of freedom simultaneously available to the user. Cognitive benefits arise as a result of reducing the load of mentally composing and visualizing the task at an unnaturally low level which is imposed by traditional unimanual techniques. Area sweeping was selected as our experimental task. It is representative of what one encounters, for example, when sweeping out the bounding box surrounding a set of objects in a graphics program. Such tasks cannot be modeled by Fitts' Law alone and have not been previously studied in the literature. In our experiments, two bimanual techniques were compared with the conventional one-handed GUI approach. Both bimanual techniques employed the two-handed &ldquo;stretchy&rdquo; technique first demonstrated by Krueger in 1983. We also incorporated the &ldquo;Toolglass&rdquo; technique introduced by Bier et al. in 1993. Overall, the bimanual techniques resulted in significantly faster performance than the status quo one-handed technique, and these benefits increased with the difficulty of mentally visualizing the task, supporting our bimanual cognitive advantage hypothesis. There was no significant difference between the two bimanual techniques. This study makes two types of contributions to the literature. First, practically we studied yet another class of transaction where significant benefits can be realized by applying bimanual techniques. Furthermore, we have done so using easily available commercial hardware in the context to our understanding of why bimanual interaction techniques have an advantage over unimanual techniques. A literature review on two-handed computer input and some of the relevant bimanual human mototr control studies is also included.
Progressive geometry compression
Authors: Andrei Khodakovsky, Peter Schröder, Wim Sweldens
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

We propose a new progressive compression scheme for arbitrary topology, highly detailed and densely sampled meshes arising from geometry scanning. We observe that meshes consist of three distinct components: geometry, parameter, and connectivity information. The latter two do not contribute to the reduction of error in a compression setting. Using semi-regular meshes, parameter and connectivity information can be virtually eliminated. Coupled with semi-regular wavelet transforms, zerotree coding, and subdivision based reconstruction we see improvements in error by a factor four (12dB) compared to other progressive coding schemes.
Elucidate: a tool to aid comprehension of concurrent object oriented execution
Authors: Chris Exton
Venue: ACM SIGCSE Bulletin (2000)

The adoption of concurrent programming techniques into mainstream system development has brought with it a problem in software comprehension. Stepping through the code is no longer adequate to ensure a student's understanding of how a concurrent program will execute. Elucidate attempts to rectify this inadequacy by giving the student the ability to dynamically explore the various threads of execution and event order of an executing concurrent program. The student can gain an understanding of the threads of control and how they relate to classes, object instantiation, destruction and method invocation. Elucidate adds a layer of abstraction that is capable of clearly exhibiting to the student many of the underlying problems associated with concurrent programming.
Information dependencies
Authors: Mehmet M. Dalkilic, Edward L. Roberston
Venue: Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2000)

This paper uses the tools of information theory to examine and reason about the information content of the attributes within a relation instance. For two sets of attributes X and Y, an information dependency measure (InD measure) characterizes the uncertainty remaining about the values for the set Y when the values for the set X are known. A variety of arithmetic inequalities (InD inequalities) are shown to hold among InD measures; InD inequalities hold in any relation instance. Numeric constraints (InD constraints) on InD measures, consistent with the InD inequalities, can be applied to relation instances. Remarkably, functional and multivalued dependencies correspond to setting certain constraints to zero, with Armstrong's axioms shown to be consequences of the arithmetic inequalities applied to constraints. As an analog of completeness, for any set of constraints consistent with the inequalities, we may construct a relation instance that approximates these constraints within any positive &egr;. InD measures suggest many valuable applications in areas such as data mining.
Analysis of Expanded Mixed Finite Element Methods for a Nonlinear Parabolic Equation Modeling Flow into Variably Saturated Porous Media
Authors: Carol S. Woodward, Clint N. Dawson
Venue: SIAM Journal on Numerical Analysis (2000)

We present an analysis of expanded mixed finite element methods applied to Richards' equation, a nonlinear parabolic partial differential equation modeling the flow of water into a variably saturated porous medium. We consider the full range of saturated to completely unsaturated media. In the case of the lowest order Raviart--Thomas spaces and the range of all possible saturations, we bound the H-1-norm of the error in capacity in terms of approximation error. This estimate uses a time-integrated scheme and the Kirchhoff transformation to handle a degeneracy in the case of completely unsaturated flow. Optimal convergence is then shown for a nonlinear form related to the error in the capacity for the case of saturated to partially saturated flow. Convergence rates depending on the Hölder continuity of the capacity term are derived. Last, optimal convergence of pressures and fluxes is stated for the case of strictly partially saturated flow.
Binomial Moments of the Distance Distribution and the Probabilityof Undetected Error
Authors: A. Barg, A. Ashikhmin
Venue: Designs, Codes and Cryptography (1999)

In [1] K. A. S. Abdel-Ghaffar derives a lower bound on the probability of undetected error for unrestricted codes. The proof relies implicitly on the binomial moments of the distance distribution of the code. We use the fact that these moments count the size of subcodes of the code to give a very simple proof of the bound in Abdel by showing that it is essentially equivalent to the Singleton bound. This proof reveals connections of the probability of undetected error to the rank generating function of the code and to related polynomials (Whitney function, Tutte polynomial, and higher weight enumerators). We also discuss some improvements of this bound. Finally, we analyze asymptotics. We show that an upper bound on the undetected error exponent that corresponds to the bound of Abdel improves known bounds on this function.
Performance re-engineering of embedded real-time systems
Authors: Minsoo Ryu, Jungkeun Park, Kimoon Kim, Yangmin Seo, Seongsoo Hong
Venue: ACM SIGPLAN Notices (1999)

This paper formulates a problem of embedded real-time system re-engineering, and presents its solution approach. The re-engineering of an embedded system is defined as a development task of meeting newly imposed performance requirements after its hardware and software have been fully implemented. The performance requirements may include a real-time throughput and an input-to-output latency. The proposed solution approach is based on a bottleneck analysis and nonlinear optimization. Inputs to the approach include a system design specified with a process network and a set of task graphs, task allocation and scheduling, and a new real-time throughput requirement specified as a system's period constraint.The solution approach works in two steps. In the first step, it determines bottleneck processes in the process network via estimation of process latencies. In the second step, it derives a system of constraints with performance scaling factors of processing elements being variables. It then solves the constraints for the performance scaling factors with an objective of minimizing the total hardware cost of the resultant system. These scaling factors suggest the minimal cost hardware upgrade to meet the new performance requirements. Since this approach does not modify carefully designed software structures, it helps reduce the reengineering cycle.
Apprenticeship learning of software engineering using Webworlds
Authors: Peter Chalk
Venue: ACM SIGCSE Bulletin (2000)

There is an increasing use of the World Wide Web in the teaching of topics in computer science. Many examples involving animation have been reported and other modeling environments (or 'Webworlds'), such as diagramming tools, are emerging. The software engineering curriculum includes topics such as testing and design, which can be supported by graphical editors. This paper presents three examples of software produced to support learning in this area and a detailed analysis of the results of one pilot research study. Taken as a whole, the evidence is argued to support the case for apprenticeship learning and that the Web provides an opportunity to exploit this, if collaborative and other tools properly scaffold it.
A distributed scientific data archive using the Web, XML and SQL/MED
Authors: Mark Papiani, Jasmin L. Wason, Alistair N. Dunlop, Denis A. Nicole
Venue: ACM SIGMOD Record (1999)

We have developed a web-based architecture and user interface for fast storage, searching and retrieval of large, distributed, files resulting from scientific simulations. We demonstrate that the new DATALINK type defined in the draft SQL Management of External Data Standard can help to overcome problems associated with limited bandwidth when trying to archive large files using the web. We also show that separating the user interface specification from the user interface processing can provide a number of advantages. We provide a tool to generate automatically a default user interface specification, in the form of an XML document, for a given database. This facilitates deployment of our system by users with little web or database development experience. The XML document can be customised to change the appearance of the interface.
On wrapping query languages and efficient XML integration
Authors: Vassilis Christophides, Sophie Cluet, Jérǒme Simèon
Venue: ACM SIGMOD Record (2000)

Modern applications (Web portals, digital libraries, etc.) require integrated access to various information sources (from traditional DBMS to semistructured Web repositories), fast deployment and low maintenance cost in a rapidly evolving environment. Because of its flexibility, there is an increasing interest in using XML as a middleware model for such applications. XML enables fast wrapping and declarative integration. However, query processing in XML-based integration systems is still penalized by the lack of an algebra with adequate optimization properties and the difficulty to understand source query capabilities. In this paper, we propose an algebraic approach to support efficient XML query evaluation. We define a general purpose algebra suitable for semistructured on XML query languages. We show how this algebra can be used, with appropriate type information, to also wrap more structured query languages such as OQL or SQL. Finally, we develop new optimization techniques for XML-based integration systems.
Instructional instruments for Web group learning systems: the grouping, intervention, and strategy
Authors: Kuo-Liang Ou, Gwo-Dong Chen, Chen-Chung Liu
Venue: ACM SIGCSE Bulletin (2000)

Owing to the lack of face-to-face interactions, students using a web-based learning system are likely to study alone and with relatively little classmate support and pressure. Teachers in a web-based learning system may apply the group-learning model to overcome this problem. Therefore, teachers first need to organize, manage, and monitor the group learning. Additionally, they must take appropriate actions based on teaching strategies to improve the learning achievements of the students. To perform these tasks effectively, the teachers must obtain relevant information by searching and analyzing the huge amount of web-access logs or by monitoring web interactions. This will be burdensome and difficult to do well for the teachers. This work presents novel methodologies for developing instruments to assist teachers in performing grouping, intervention and strategy analysis. The proposed methodologies apply data mining tools provided by existing database management systems. A tool is initially R developed to assist in organizing learning groups according to teacher specifications. Database techniques, including multidimensional cube, are then applied to make student web logs meaningful and helpful to teachers in managing group learning. The associate rule mining tool is finally employed to assist teachers in analyzing their pedagogical strategies. These tools relieve the teacher of tedious data collection and analysis, and thus can focus on managing the groups to promote student learning achievement.
Worst-case analysis of discrete systems
Authors: Felice Balarin
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

We propose a methodology for worst-case analysis of systems with discrete observable signals. The methodology can be used to verify different properties of systems such as power consumption, timing performance or resource utilization. We also propose an application of the methodology to timing analysis of embedded systems implemented on a single processor. The analysis provides a bound on the response time of such systems. It is typically very efficient, because it does not require a state space search.
The theory of direct probability redistribution and its application to rare event simulation
Authors: Zsolt Haraszti, J. Keith Townsend
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1999)

Rare event simulation is an important area of simulation theory, producing algorithms that can significantly reduce the simulation time when analyzing problems that involve rare events. However, existing rare event simulation techniques are rather restrictive, i.e., applicable only to systems with modest complexity. In this paper, we first develop a Markov chain transformation theory that can redistribute steady-state probabilities in a finite-size discrete-time Markov chain in an arbitrary and controlled manner. We descriptively name the theoretical procedure &ldquo;direct probability redistribution&rdquo; (DPR). In the second part of the paper, we develop DPR theory into a simulation algorithm that uses trajectory splitting to realize the DPR effect without knowledge of the transition probability matrix, thus allowing for easy application to systems with realistic complexity. DPR-based splitting can significantly reduce the simulation time by increasing the visitng frequency of rare states, and it avoids the problems associated with the decreasing likelihood ratio, which can be a limitation in conventional Importance Sampling techniques. The main advantage of the DPR-based simulation technique over existing splitting techniques is that DPR does not impose any restrictions on the state transitions and it provides asymptotically unbiased estimates even if the rare event set overlaps many splitting partitions. We conclude by providing examples where DPR-based simulation has been successfully applied to nontrivial queuing problems, including a system with flow control.
Two Arc-Disjoint Paths in Eulerian Digraphs
Authors: András Frank, Toshihide Ibaraki, Hiroshi Nagamochi
Venue: SIAM Journal on Discrete Mathematics (1998)

Let G be an Eulerian digraph, and let {x1, x2}, {y1,y2} be two pairs of vertices in G. A directed path from a vertex s to a vertex t is called an st-path. An instance (G;{x1, x2}, {y1,y2}) is called feasible if there is a choice of h,i,j,k with {h,i} = {j,k} = {1,2} such that G has two arc-disjoint xhxi- and yjyk-paths. In this paper, we characterize the structure of minimal infeasible instances, based on which an O(m+nlog n) time algorithm is presented to decide whether a given instance is feasible, where n and m are the number of vertices and arcs in the instance, respectively. If the instance is feasible, the corresponding two arc-disjoint paths can be computed in O(m(m+nlog n)) time.
Broadcasting Multiple Messages in the Multiport Model
Authors: Amortz Bar-Noy, Ching-Tien Ho
Venue: IEEE Transactions on Parallel and Distributed Systems (1999)

We consider the problem of broadcasting multiple messages from one processor to many processors in the $k$-port model for message-passing systems. In such systems, processors communicate in rounds, where in every round, each processor can send $k$ messages to $k$ processors and receive $k$ messages from $k$ processors. In this paper, we first present a simple and practical algorithm based on variations of $k$ complete $k$-ary trees. We then present an optimal algorithm up to an additive term of one for this problem for any number of processors, any number of messages, and any value for $k$.