ppxscal/embedding_network huggingface dataset:
Dimension Reduction in the \ell _1 Norm
Authors: Moses Charikar, Amit Sahai
Venue: Proceedings of the 43rd Symposium on Foundations of Computer Science (2002)

The Johnson-Lindenstrauss Lemma shows that any set of n points in Euclidean space can be mapped linearly down to O0({{(\log n)} \mathord{\left/ {\vphantom {{(\log n)} {\varepsilon ^2 }}} \right. \kern-\nulldelimiterspace} {\varepsilon ^2 }}) dimensions such that all pairwise distances are distorted by at most 1 + \varepsilon. We study the following basic question: Does there exist an analogue of the Johnson-Lindenstrauss Lemma for the \ell _1 norm?Note that Johnson-Lindenstrauss Lemma gives a linear embedding which is independent of the point set. For the \ell _1 norm, we show that one cannot hope to use linear embeddingsas a dimensionality reduction tool for general point sets, even if the linear embedding is chosen as a function of the given point set. In particular, we construct a set of O(n) points in n\ell _1^n such that any linear embedding into \ell _1^d must incur a distortion of \Omega (\sqrt {{n \mathord{\left/ {\vphantom {n d}} \right. \kern-\nulldelimiterspace} d}}). This bound is tight up to a log n factor. We then initiate a systematic study of general classes of \ell _1 embeddable metrics that admit low dimensional, small distortion embeddings. In particular, we show dimensionality reduction theorems for tree metrics, circular-decomposable metrics, and metrics supported on K2,3-free graphs, giving embeddings into \ell _1 withconstant distortion. Finally, we also present lower bounds on dimension reduction techniques for other \ell _p norms.Our work suggests that the notion of a stretch-limited embedding, where no distance is stretched by more than a factor d in any dimension, is important to the study of dimension reduction for \ell _1. We use such stretch limited embeddings as a tool for proving lower bounds for dimension reduction and also as an algorithmic tool for proving positive results.
Dancing hamsters and marble statues: characterizing student visualizations of algorithms
Authors: Teresa Hübscher-Younger, N. Hari Narayanan
Venue: Proceedings of the 2003 ACM symposium on Software visualization (2003)

Algorithm visualization research for computer science education has primarily focused on expert-created visualizations. However, constructionist and situated theories of learning suggest that students should develop and share their own diverse understandings of a concept for deep learning. This paper presents a novel approach to algorithm learning by visualization construction, sharing, and evaluation. Three empirical studies in which students engaged in these activities are discussed. The resulting learning benefits are quantified, and student visualizations are characterized in multiple ways. Then another study that investigated how specific characteristics of such visualizations influence learning is described. This work demonstrates the effectiveness of having students create algorithm visualizations, identifies characteristics of student-created algorithm visualizations and illuminates the learning benefits derived from these characteristics.
An Adaptive Dynamic Programming Algorithm for Dynamic Fleet Management, I: Single Period Travel Times
Authors: Gregory A. Godfrey, Warren B. Powell
Venue: Transportation Science (2002)

We consider a stochastic version of a dynamic resource allocation problem. In this setting, reusable resources must be assigned to tasks that arise randomly over time. We solve the problem using an adaptive dynamic programming algorithm that usesnonlinear functional approximations that give the value of resources in the future. Our functional approximations are piecewise linear and naturally provide integer solutions. We show that the approximations provide near-optimal solutions to deterministic problems and solutions that significantly outperform deterministic rolling-horizon methods on stochastic problems.
Is Organization Theory Obvious to Practitioners? A Test of One Established Theory
Authors: Richard L. Priem, Joseph Rosenstein
Venue: Organization Science (2000)

Critics have argued that organization theories which "work" are obvious to practitioners; that is, the theories simply confirm relationships that are already well understood by experienced managers. In our study, four types of respondents--Chief Executive Officers (CEOs) with business school education, CEOs without such education, graduating MBA students, and liberal arts graduate students--were presented with theory-based performance-rating tasks. These tasks identified respondents' beliefs regarding high-performance alignments of businesslevel strategy, structure, and environment for manufacturing firms. The respondents' cause maps were then compared to one another and to the alignment-performance relationships prescribed by business-level contingency theory.The graduating MBAs' cause maps reflected contingency theory most closely. The MBAs' cause maps weremuch closer to prescriptions of the theory, however, than were those of either the liberal arts graduate students or the experienced CEOs. This suggests that business-level contingency theory isnot obvious to educated laypersons,or to highly experienced practitioners; both groups would find that the theorydisconfirms aspects of their causal expectations. Further, each of the four respondent types in our study emphasizeddifferent contingency factors during the decision-making exercise. We discuss these results and their implications.
The simplest heuristics may be the best in Java JIT compilers
Authors: Jonathan L. Schilling
Venue: ACM SIGPLAN Notices (2003)

The simplest strategy in Java just-in-time (JIT) compilers is to compile each Java method the first time it is called. However, better performance can often be obtained by selectively compiling methods based on heuristics of how often they are likely to be called during the rest of the program's execution. Various heuristics are examined when used as part of the Caldera UNIX Java JIT compiler. The simplest heuristics involving the number of times the method has executed so far and the size of the method prove to be the most effective, with more complicated heuristics not providing much or any additional benefit.
An interactive poster exhibit puts visitors in the picture, in real time
Authors: Kevin Walker
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This describes the usability and interaction challenges in creating a unique museum exhibit which utilizes real-time compositing, and hides complex computational tasks behind a simple user interface.
A multichannel watershed-based algorithm for supervised texture segmentation
Authors: Norberto Malpica, Juan E. Ortuño, Andrés Santos
Venue: Pattern Recognition Letters (2003)

Segmentation of image regions based on their texture is a standard problem in image analysis. Once a set of texture features is selected, several algorithms can be applied to segment the image into regions. This paper presents an extension of the watershed algorithm using a vector gradient and multivariate region merging methods. The algorithm uses a set of texture images, and it only depends on an adjustable parameter. Results are presented on a standard set of synthetic images and on textured medical ones, using different texture parameters and merging criteria.
Web retrieval of XML documents: practice and challenges
Authors: Barbara Catania, Elena Ferrari
Venue: Web-enabled systems integration: practices and challenges (2003)

Web is characterized by a huge amount of very heterogeneous data sources, that differ both in media support and format representation. In this scenario, there is the need of an integrating approach for querying heterogeneous Web documents. To this purpose, XML can play an important role since it is becoming a standard for data representation and exchange over the Web. Due to its flexibility, XML is currently being used as an interface language over the Web, by which (part of) document sources are represented and exported. Under this assumption, the problem of querying heterogeneous sources can be reduced to the problem of querying XML data sources. In this chapter, we first survey the most relevant query languages for XML data proposed both by the scientific community and by standardization committees, e.g., W3C, mainly focusing on their expressive power. Then, we investigate how typical Information Retrieval concepts, such as ranking, similarity-based search, and profile-based search, can be applied to XML query languages. Commercial products based on the considered approaches are then briefly surveyed. Finally, we conclude the chapter by providing an overview of the most promising research trends in the fields.
Exact results for accepting probabilities of quantum automata
Authors: Andris Ambainis, Arnolds Ķikusts
Venue: Theoretical Computer Science (2003)

One of the properties of the Kondacs-Watrous model of quantum finite automata (QFA) is that the probability of the correct answer for a QFA cannot be amplified arbitrarily. In this paper, we determine the maximum probabilities achieved by QFAs for several languages. In particular, we show that any language that is not recognized by an RFA (reversible finite automaton) can be recognized by a QFA with probability at most 0.7726 ....
Exploring the Relationship between Project Selection and Requirements Analysis: An Empirical Study of the New Millennium Program
Authors: Mark Bergman, Gloria Mark
Venue: Proceedings of the 10th Anniversary IEEE Joint International Conference on Requirements Engineering (2002)

The relationship between project selection and requirements analysis is important, yet has not received much attention. The decisions made during project selection directly affect and frame a project's requirements analysis. In current practice, it is expected that requirements analysis begins after project selection has occurred. Yet, we know little empirically about theprocedural relationship between project selection and requirements analysis. We performed a field study to examine in detail how project selection is performed and what procedural relationship, if any, exists between project selection and requirements analysis. We found, contrary to the common view of requirements engineering practice, that requirements analysis occurred in multiple parallel streams. We observed that requirements analysis helped define the initial project choices. In addition, as the project selection process progressed, each candidate project's requirements were further refined. We call this process multiple parallel competitive requirements analysis (MPCRA). We argue that MPCRA should be considered as a viable alternative to current requirements engineering practices, especially for determining and designing large-scale complex projects.
Advanced pollutant emissions computer system (APEX 4.0)
Authors: C. Trozzi, E. Piscitello, S. Giammarino, R. Vaccaro
Venue: Development and application of computer techniques to environmental studies (2002)

In the last year air pollutant emissions inventories are widely developed around the world. Most data used for the realization of area and mobile sources air emissions inventories can be also used for other media (water, wastes, noise, soil) emissions inventory. A lot of emissions factors are available, or can be evaluated, for area and mobile sources emissions inventories in other media (water, wastes, noise, soil). Regarding point sources, legislation was developed concerning integrated emissions registers. Previous papers have described the software tools used in the development of emissions inventories in Italy. In this work will be discussed a new computer system (APEX 4.0) to build emissions inventories in different environmental media (air, water, soil, wastes, noise, radiation). Examples from an Italy regional case study application (in the frame of Liguria Region ECOZERO project) will be reported.
Adjustment Strategies for a Fixed Delivery Contract
Authors: Kamran Moinzadeh, Steven Nahmias
Venue: Operations Research (2000)

We consider a long term contractual agreement between buyer and seller in whichQ units are delivered to the buyer at regular time intervals. It must be true that the delivery quantity,Q, is less than the mean demand per period. In order to manage the inventory, the buyer has the option of adjusting the delivery quantity upwards just prior to a delivery, but must pay a premium to do so. Demand is assumed random, and we model the system in a continuous review setting. We show that the equations one must solve to find optimal adjustment strategies are intractable. A diffusion approximation is developed which when coupled with the solution to an even simpler deterministic version of the problem yields very simple but effective approximations. Extensive computations are included to compare the performance of the optimal and approximate policies. We also empirically derive a formula for computingQ whose accuracy is established computationally. We prove that the fixed delivery contract results in lower variance of orders to the seller. We also include a computational study to find the unit cost discount that equalizes the expected costs for the fixed delivery contract and the base stock contract for a large parameter set.
Efficient Intelligent Backtracking Using Linear Programming
Authors: Bruce Davey, Natashia Boland, Peter J. Stuckey
Venue: INFORMS Journal on Computing (2002)

Intelligent backtracking is a technique used in constraint programming for reducing search in solving combinatorial feasibility problems. The technique uses information derived from small sets of infeasible constraints discovered in one part of the search space to avoid searching other, similar, regions. It is often able to reduce the size of the search space significantly. For many problems, however, the computational effort required to achieve this reduction in search space is prohibitive. We introduce an algorithm that uses intelligent backtracking inside a linear-programming based branch-and-bound framework. We show that minimal infeasible sets can immediately be deduced from the dual extreme ray associated with the infeasible linear program. This allows us to obtain the reduction in search space associated with intelligent backtracking, without paying the large computational cost. We show the implementation of our intelligent backtracking approach as a branch-and-cut algorithm, and present computational results.
Analysis of an Anonymity Network for Web Browsing
Authors: Marc Rennhard, Sandro Rafaeli, Laurent Mathy, Bernhard Plattner, David Hutchison
Venue: Proceedings of the 11th IEEE International Workshops on Enabling Technologies: nfrastructure for Collaborative Enterprises (2002)

Various systems offering anonymity for near real-time Internet traffic have been operational. However, they did not deliver many quantitative results about performance, bandwidth overhead, or other issues that arise when implementing or operating such a system. Consequently, the problem of designing and operating these systems in a way that they provide a good balance between usability, protection from attacks, and overhead is not well understood. In this paper, we present the analysis of an anonymity network for web browsing that offers a high level of anonymity against a sophisticated attacker and good end-to-end performance at a reasonable bandwidth overhead. We describe a novel way of operating the system that maximizes the protection from traffic analysis attacks while minimizing the bandwidth overhead. We deliver quantitative results about the performance of our system, which should help to give a better understanding of anonymity networks.
Learning Red Hat Linux, 3 edition
Authors: Bill McCarty
Venue:  (2003)

: New users are flocking to Linux literally by the millions. Yet most of these new users draw from Microsoft Windows as their primary computing experience; for them an operating system from the UNIX family is an unfamiliar experience. In Learning Red Hat Linux, Bill McCarty has written a book aimed specifically at this new audience. Learning Red Hat Linux will guide any new user of Linux through the installing and use of Red Hat Linux, the free operating system that is shaking up the commercial world of software. It demystifies Linux in terms familiar to Windows users and gives readers only what they need to start being successful users of Linux. Built around the popular Red Hat distribution of Linux, Learning Red Hat Linux takes the reader step by step through the process of installing and setting up a Red Hat Linux system, and provides a thorough but gentle introduction to the basics of using Red Hat Linux. Because the book is written specifically for the enclosed CD, the reader needs nothing else to get started with this exciting new operating system.
An aqueous algorithm for finding the bijections contained in a binary relation
Authors: Tom Head
Venue: Formal and natural computing (2002)

Given a subset R of a set A × B, one may ask whether R contains a subset F which is a bijective function from A onto B. Awet lab algorithm for answering this question is presented. Moreover, when such a bijection is contained in R, the algorithm produces a test tube containing a set of DNA plasmids, each of which encodes such a bijection. The number of steps required by the given procedure grows linearly with the number of ordered pairs in the relation R. All known algorithms for solving this bijection problem on conventional computers require a number of steps that grows exponentially in the number of pairs. Various forms of the Hamiltonian path problem are subsumed by the problem of finding such bijections. The algorithm presented is illustrated by outlining its application to the binary relation determined by the directed graph that occurs in the instance of the directed Hamiltonian path problem with which L. Adleman initiated DNA computing.
Fast modular exponentiation of large numbers with large exponents
Authors: Giuseppe Alia, Enrico Martinelli
Venue: Journal of Systems Architecture: the EUROMICRO Journal (2002)

In many problems, modular exponentiation |xb|m is a basic computation, often responsible for the overall time performance, as in some cryptosystems, since its implementation requires a large number of multiplications.It is known that |xb|m = |x|b|φ(m)|m for any x in [1, m- 1] if m is prime; in this case the number of multiplications depends on φ(m) instead of depending on b. It was also stated that previous relation holds in the case m = pq, with p and q prime; this case occurs in the RSA method.In this paper it is proved that such a relation holds in general for any x in [1, m - 1] when m is a product of any number n of distinct primes and that it does not hold in the other cases for the whole range [1, m - 1].Moreover, a general method is given to compute |xb|m without any hypothesis on m, for any x in [1, m - 1], with a number of modular multiplications not exceeding those required when m is a product of primes.Next, it is shown that representing x in a residue number system (RNS) with proper moduli mi allows to compute |xb|m by n modular exponentiations |xib|mi in parallel and, in turn, to replace b by |b|φ(mi in the worst case, thus executing a very low number of multiplications, namely ⌈log2mi⌉ for each residue digit.A general architecture is also proposed and evaluated, as a possible implementation of the proposed method for the modular exponentiation.
The Net-Enabled Business Innovation Cycle and the Evolution of Dynamic Capabilities
Authors: Shaker A. Zahra, Gerard George
Venue: Information Systems Research (2002)

Wheeler's Net-Enabled Business Innovation Cycle (NEBIC) integrates IS and strategy research to offer an interesting and timely perspective on value creation. We extend Wheeler's theoretical propositions, highlighting the interplay between strategy, IS, and entrepreneurship in a quest for competitive advantage. This interplay is crucial to the creation of the dynamic capabilities that enable companies to gain an advantage through NEBIC. The importance of opportunity recognition and absorptive capacity in bringing about the changes that make NEBIC viable is also highlighted.
Automatic mesh generation on a regular background grid
Authors: S. H. Lo, Jianfei Liu
Venue: Journal of Computer Science and Technology (2002)

This paper presents an automatic mesh generation procedure on a 2D domain based on a regular background grid. The idea is to devise a robust mesh generation scheme with equal emphasis on quality and efficiency. Instead of using a traditional regular rectangular grid, a mesh of equilateral triangles is employed to ensure triangular element of the best quality will be preserved in the interior of the domain.As for the boundary, it is to be generated by a node/segment insertion process. Nodes are inserted into the background mesh one by one following the sequence of the domain boundary. The local structure of the mesh is modified based on the Delaunay criterion with the introduction of each node. Those boundary segments, which are not produced in the phase of node insertion, will be recovered through a systematic element swap process. Two theorems will be presented and proved to set up the theoretical basic of the boundary recovery part. Examples will be presented to demonstrate the robustness and the quality of the mesh generated by the proposed technique.
A Simulation-Based Approach to Understanding the Dynamics of Innovation Implementation
Authors: Nelson P. Repenning
Venue: Organization Science (2002)

The history of management practice is filled with innovations that failed to live up to the promise suggested by their early success. A paradox currently facing organizational theory is that the failure of these innovations often cannot be attributed to an intrinsic lack of efficacy. To resolve this paradox, in this paper I study the process ofinnovation implementation. Working from existing theoretical frameworks, I synthesize a model that describes the process through which participants in an organization develop commitment to using a newly adopted innovation. I then translate that framework into a formal model and analyze it using computer simulation. The analysis suggests three new constructs--reversion, regeneration, and the motivation threshold--characterizing the dynamics of implementation. Taken together, the constructs provide an internally consistent theory of how seemingly rational decision rules can create the apparent paradox of innovations that generate early results but fail to produce sustained benefit.
On the Value of Binary Expansions for General Mixed-Integer Linear Programs
Authors: Jonathan H. Owen, Sanjay Mehrotra
Venue: Operations Research (2002)

We study the use of binary variables in reformulating general mixed-integer linear programs. We show that binary reformulations result in problems for which almost all the binary variables replacing a general integer variable need to be explored during branching. We also give computational results on the performance of such reformulations in solving the mixed-integer programs, which support our theoretical results.