ppxscal/embedding_network huggingface dataset:
Does an interface with less assistance provoke more thoughtful behavior?
Authors: Christof van Nimwegen, Herre van Oostendorp, Daniel Burgos, Rob Koper
Venue: Proceedings of the 7th international conference on Learning sciences (2006)

This paper investigates effects of interface style and cognitive style on problem solving performance. It is often assumed that performance improves when information is externalized onto the interface. Although relieving working memory this may discourage planning, understanding and knowledge acquisition. When information is not externalized, it must be internalized, stored in the user's memory, requiring more planning and thinking, perhaps leading to better performance and knowledge. Another variable influencing behavior is the cognitive style of users. We included "Need for Cognition" (NFC), the tendency to engage in cognitive tasks. We investigated the effects of interface style and NFC using planning tasks. The internalization interface led to more planful behavior and smarter solutions, but NFC had no effect. Understanding reactions to interface information is crucial in designing software aimed at education and learning. To facilitate active learning and provoke better performance, designers should take care in giving users (too) much assistance.
Probabilistic temporal logics via the modal mu-calculus
Authors: Rance Cleaveland, S. Purushothaman Iyer, Murali Narasimha
Venue: Theoretical Computer Science (2005)

This paper presents a mu-calculus-based modal logic for describing properties of reactive probabilistic labeled transition systems (RPLTSs) and develops a model-checking algorithm for determining whether or not states in finite-state RPLTSs satisfy formulas in the logic. The logic is based on the distinction between (probabilistic) "systems" and (nonprobabilistic) "observations": using the modal mu-calculus, one may specify sets of observations, and the semantics of our logic then enable statements to be made about the measures of such sets at various system states. The logic may be used to encode a variety of probabilistic modal and temporal logics; in addition, the model-checking problem for it may be reduced to the calculation of solutions to systems of non-linear equations. Finally, the logic induces an equivalence on RPLTSs that coincides with accepted notions of probabilistic bisimulation in the literature.
Effects of Attention on Neuroelectric Correlates of Auditory Stream Segregation
Authors: Joel S. Snyder, Claude Alain, Terence W. Picton
Venue: Journal of Cognitive Neuroscience (2006)

A general assumption underlying auditory scene analysis is that the initial grouping of acoustic elements is independent of attention. The effects of attention on auditory stream segregation were investigated by recording event-related potentials (ERPs) while participants either attended to sound stimuli and indicated whether they heard one or two streams or watched a muted movie. The stimuli were pure-tone ABA&ndash; patterns that repeated for 10.8 sec with a stimulus onset asynchrony between A and B tones of 100 msec in which the A tone was fixed at 500 Hz, the B tone could be 500, 625, 750, or 1000 Hz, and &ndash; was a silence. In both listening conditions, an enhancement of the auditory-evoked response (P1&ndash;N1&ndash;P2 and N1c) to the B tone varied with &Delta;f and correlated with perception of streaming. The ERP from 150 to 250 msec after the beginning of the repeating ABA&ndash; patterns became more positive during the course of the trial and was diminished when participants ignored the tones, consistent with behavioral studies indicating that streaming takes several seconds to build up. The N1c enhancement and the buildup over time were larger at right than left temporal electrodes, suggesting a right-hemisphere dominance for stream segregation. Sources in Heschl's gyrus accounted for the ERP modulations related to &Delta;f-based segregation and buildup. These findings provide evidence for two cortical mechanisms of streaming: automatic segregation of sounds and attention-dependent buildup process that integrates successive tones within streams over several seconds.
The Effects of Presentation Rate During Word and Pseudoword Reading: A Comparison of PET and fMRI
Authors: Andrea Mechelli, Karl J. Friston, Cathy J. Price
Venue: Journal of Cognitive Neuroscience (2000)

The effect of stimulus rate and its interaction with stimulus type on brain activity during reading was investigated using functional magnetic resonance imaging (fMRI). This (i) enabled the segregation of brain regions showing differential responses, (ii) identified the optimum experimental design parameters for maximizing sensitivity, and (iii) allowed us to evaluate further the sources of discrepancy between positron emission tomography (PET) and fMRI signals. The effect of visual word rate has already been investigated in a previous PET study. However, rate effects can be very different in PET and fMRI, as seen in previous studies of auditory word processing. In this work, we attempt to replicate rate-sensitive activations observed with PET using fMRI. Our objective was to characterize the discrepancies in regionally specific ratesensitive effects between the two imaging modalities. Subjects were presented with words and pseudowords at varying rates while performing a silent reading task. The analysis specifically identified regions showing (i) an effect of stimulus rate on brain activity during reading; (ii) modulation of this effect by word type; and (iii) increased activity during reading relative to rest, but with no dependence on stimulus rate. The results identified similar effects of rate for words and pseudowords (no interactions between rate and word type reached significance). Irrespective of word type, strong positive linear effects of rate (i.e., activity increasing with rate) were detected in visual areas, right superior temporal gyrus, and bilateral precentral gyrus. These findings replicate the results of the previous PET study, confirming that activation in regions associated with visual processing and response generation increases with the number of stimuli. Likewise, we detected rate-independent effects reported in the previous PET study in bilateral anterior middle temporal, inferior frontal, and superior parietal regions. These results differentiate the functionally specific responses in rate-dependent and rate-independent areas. However, for negative effects of rate, fMRI did not replicate the effects seen in PET, suggesting some form of hemodynamic "rectification." The discussion focuses on differences between evoked rCBF and BOLD signals.
Weyuker and Barbacci Honored with Society Awrds
Venue: Computer (2006)

Elaine Weyuker won the 2004 Harlan D. Mills Award, and Mario Barbacci received the 2005 Richard E. Merwin Award.
Validation of transfer maps using Taylor models
Authors: M. Berz, K. Makino
Venue: Proceedings of the 2003 International Conference on Physics and Control - Volume 3 (2003)

Summary form only given. High-order transfer maps of particle systems play an important. role in the design and optimization of particle optical systems, both for satisfying the basic design needs as well as for the correction of aberrations and non-linear effects. The differential algebraic method has proved useful for this problem, allowing the computation of maps of arbitrary order of systems described by arbitrary electromagnetic fields. Since the high-order maps represent an approximation of the motion, in particular in strongly nonlinear cases in which convergence of the maps may he slow, it is important to know the quality of the approximation. Recent work has shown that it is in principle possible to not only propagate the conventional differential algebraic high-order objects, but also adjoint. remainder terms that rigorously account for any errors made both by the integrator scheme and any possibly inaccuracy of the description of the system. In this paper we describe various recent enhancements of the original method of maps with remainder bounds. First we address a variable doubling scheme that allows the treatment of the remainder effect themselves in terms of a transfer map-like relationship instead of a mere box. Using suitable extensions of the DA and Taylor model operators used in the Schauder fixed point theorem formulation of the problem, this approach is in practice nearly as transparent as the original method and leads to a significant enhancement of sharpness. Under the presence of a scheme for effective treatment of sparsity in the DA vectors, such as the method available in the code COSY INFINITY, the additional resources necessary for this algorithm are very modest. Next we describe a method for the treatment of the one-step approximation errors of the integration scheme called shrink wrapping. It allows the re-absorption of these approximation errors that are initially merely given by an n-dimensional box into the remainder terms described by the variable doubling. Using the combination of these effects, the already rather tight bounds for the approximation errors of transfer maps can be further significantly reduced, and it is even possible to estimate bounds on the overestimation of those error inclusions themselves.
SKVR: scalable knowledge-based routing architecture for public transport networks
Authors: Shabbir Ahmed, Salil S. Kanere
Venue: Proceedings of the 3rd international workshop on Vehicular ad hoc networks (2006)

Vehicular AdHoc Networks (VANET) can be treated as special kinds of Delay-tolerant Networks (DTN) where end-to-end path might never be possible. As a result, mobile adhoc (MANET) routing protocols perform poorly on DTNs. Moreover, traditional routing architecture is not scalable for public transport networks with large numbers of nodes (public transports). In this paper, we introduce a hierarchical knowledge-based DTN routing scheme for public transport networks that is not only scalable but also communication efficient. We evaluate our design using simulation with real bus traces.
Authoring learning environments using an embedded pedagogical model
Authors: Smadar Kedar, David Guralnick, Ann Holum, Ray Bareiss, Richard Beckwith, Alex Kass
Venue: Proceedings of the 1996 international conference on Learning sciences (1996)

For computer-based learning environments to make a major impact on education, we need tools to scale up construction of these systems in order to deploy the technology. On the one hand, commercial authoring tools can be used by educators to ease construction of learning environments. However, these tools provide no guidance in terms of pedagogy. On the other hand, construction tools for intelligent tutoring systems (ITSs) can assist educators in authoring tutoring systems by helping them encode instructional content, but many require authors to specify explicit models such as teaching strategies and student models. Although the resulting software is pedagogically principled, encoding these models is cumbersome. For educators to create quality tutoring programs with relative ease, our approach combines the commitment to pedagogy of the ITS tools, with the ease of authoring of off-the-shelf tools. by embedding a pedagogical model implicitly in a tool. The embedded model ensures that the resulting learning environments will be pedagogically sound, while freeing educators to concentrate on curriculum content. We demonstrate this with a case study of a prototype authoring tool, Investigative Goal-Based Scenario (IGBS) Builder, intended for educators building multimedia learning environments using an embedded pedagogical model of situated instruction.
Utility Optimization for Event-Driven Distributed Infrastructures
Authors: Cristian Lumezanu, Sumeer Bhola, Mark Astley
Venue: Proceedings of the 26th IEEE International Conference on Distributed Computing Systems (2006)

Event-driven distributed infrastructures are becoming increasingly important for information dissemination and application integration. We examine the problem of optimal resource allocation for such an infrastructure composed of an overlay of nodes. Resources, like CPU and network bandwidth, are consumed by both message flows and message consumers; therefore, we consider both rate control for flows and admission control for consumers. This makes the optimization problem difficult because the objective function is nonconcave and the constraint set is nonconvex. We present LRGP (Lagrangian Rates, Greedy Populations), a scalable and efficient distributed algorithm to maximize the total system utility. The key insight of our solution involves partitioning the optimization problem into two types of subproblems: a greedy allocation for consumer admission control and a Lagrangian allocation to compute the flow rates, and linking the subproblems in a manner that allows tradeoffs between consumer admission and flow rates while satisfying the nonconvex constraints. LRGP allows an autonomic approach to system management where nodes collaboratively optimize aggregate system performance. We evaluate the quality of results and convergence characteristics under various workloads.
Worst case timing analysis of input dependent data cache behavior
Authors: Jan Staschulat, Rolf Ernst
Venue: Proceedings of the 18th Euromicro Conference on Real-Time Systems (2006)

Data caches significantly reduce the average memory access time and are necessary for an efficient design. Due to its direct dependency on input data is is difficult to predict the worst case timing behavior, which is crucial for a reliable system. While simulation is too time-consuming, current worst case execution time approaches focus on instruction caches only. Current approaches to data cache analysis restrict cache behavior to predictable data accesses or classify input dependent memory accesses as non-cacheable. In this paper we propose a worst case timing analysis for direct mapped data caches that classifies memory accesses as predictable or unpredictable. For unpredictable memory accesses, a novel analysis framework is proposed that tightly bounds the impact on the existing cache contents as well as cache behavior of unpredictable memory accesses themselves. For predictable memory accesses, we use a local cache simulation and data flow techniques. Furthermore, we describe an implementation of the analysis framework. Several experiments demonstrate its applicability. The approach targets real-time software verification but is also useful for design space exploration.
Improved watershed segmentation using water diffusion and local shape priors
Authors: Hieu T. Nguyen, Qiang Ji
Venue: Proceedings of the 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition - Volume 1 (2006)

The watershed algorithm has many nice properties in terms of robustness to image noise, topology, and effective handling non-rigid deformations. It also has drawbacks including oversegmentation and lack of regularization. We present new methods to overcome these drawbacks. We propose a novel region merging algorithm based on the water diffusion principle. Starting with a large number of markers, lakes formed around the markers are merged in the order they meet during the immersion. The merging is not performed immediately but delayed until the amount of water diffusion between two lakes is significant enough to overwhelm the small lake. The delay makes the merging result robust to "leaks" in object boundaries, when weak edges could trigger the merging of object into the background as in traditional methods. Regularization is achieved by imposing priors of local shape configurations. Local shape features are extracted from Gaussian derivatives of the object indicator function. The ensemble of shape features at multiple scales increases representation power. These features are used to incorporate smoothness and domain knowledge into the evolution of region boundaries in the watershed algorithm. The method has been successfully applied to segmentation of worms.
Toward Formal-Methods Oecumenism?
Authors: Fabrice Kordon, Laure Petrucci
Venue: IEEE Distributed Systems Online (2006)

Arguing that there's only one way to do formal methods is common practice, when in fact interoperability between formal methods can and should be achieved.
Improved Secret Sharing with Access Structures in a Hierarchy
Authors: Yi Liu, Ling Zhang, Yumin Wang
Venue: Proceedings of the 2006 IEEE Asia-Pacific Conference on Services Computing (2006)

In 2004, Chang et al. presented an approach firstly to solve the problem of secret sharing with access structures in a hierarchy. After that, based on one way hash function, another proposed scheme was suggested by Lin et al. However, there is the same drawback in both schemes. When group secret keys need to be changed, the trust authority has to update related parameters of each branch in both the above schemes. In this paper, using discrete logarithm, an improved secret sharing with access structures in a hierarchy is given. It can achieve the property that related parameters do not have to update even if group secret keys are altered. So, the presented scheme may be more suitable for applications.
ASAP: an AS-Aware Peer-Relay Protocol for High Quality VoIP
Authors: Shansi Ren, Lei Guo, Xiaodong Zhang
Venue: Proceedings of the 26th IEEE International Conference on Distributed Computing Systems (2006)

Peer-to-peer (P2P) technology has been successfully applied in Internet telephony or Voice over Internet Protocol (VoIP), such as the Skype system, where P2P is used for both searching clients and relaying voice packets. Selecting one or multiple suitable peers to relay voice packets is a critical factor for the quality, scalability and cost of a VoIP system. In this paper, we first present two sets of intensive Internet measurement results to confirm the benefits gained by peer relays in VoIP, and to investigate the performance of the Skype system. We obtain the following results: (1) many relay peer selections are suboptimal; (2) the waiting time to select a relay node can be quite long; and (3) there are a large number of unnecessary probes, resulting in heavy network traffic to limit scalability of the VoIP system. Our further analysis shows that two main reasons cause these problems. First, the peer selections do not take Autonomous System (AS) topology into consideration, and second, the complex communication relationships among peers are not well utilized. Motivated by our measurements and analysis, we propose an AS-aware peer-relay protocol called ASAP. Our objective is to significantly improve VoIP quality and system scalability with low overhead. Our intensive evaluation by trace-driven simulation shows ASAP is highly effective and easy to implement on the Internet for building large and scalable VoIP systems.
The next wave of gender projects in IT curriculum teaching at universities
Authors: Sue Lewis, Judy McKay, Catherine Lang
Venue: Proceedings of the 8th Austalian conference on Computing education - Volume 52 (2006)

This paper investigates the 'new' crisis in the low numbers of women choosing to study Information and Communication Technology (ICT) courses at universities in Australia and indeed around the western industrialised world. In Australian universities, the spectre of all male ICT classes is becoming more commonplace, particularly in the more technically focused courses. We are hypothesing that this is no 'new' crisis at all but simply a further consolidation of a pattern that has been evident for 20 years. The range of 'gender' interventions at universities in the 1990's was primarily directed at the 'numbers problem' and was largely focused on women rather than reviewing and reforming curriculum, teaching and assessment practices as well. Past interventions have failed to impact significantly on the sex stereotype that has emerged in ICT education in most universities. Projects are now being developed that redirect intervention efforts into curriculum and teaching strategies inside ICT faculties. This paper reports on such a 'gender project' in Australia.The Australian context for this issue is explored: there has been very little research in ICT faculties on the impact of curriculum and teaching practices on the recruitment and retention of women in these faculties. We profile the Australian Course Experience (CEQ) data and local survey results from our own technological University which report student views of teaching and learning. Nationally, the ICT teaching area achieved the lowest ratings from graduate students in 2003. At our University, we found a gender gap in the first-year classroom experiences of women and men. Our broad findings suggest the need for a professional review of the very definitions of success in ICT education and support for the proliferation and evaluation of innovative and context driven curricula.
Efficient parallel processing of range queries through replicated declustering
Authors: Hakan Ferhatosmanoglu, Ali Şaman Tosun, Guadalupe Canahuate, Aravind Ramachandran
Venue: Distributed and Parallel Databases (2006)

A common technique used to minimize I/O in data intensive applications is data declustering over parallel servers. This technique involves distributing data among several disks so as to parallelize query retrieval and thus, improve performance. We focus on optimizing access to large spatial data, and the most common type of queries on such data, i.e., range queries. An optimal declustering scheme is one in which the processing for all range queries is balanced uniformly among the available disks. It has been shown that single copy based declustering schemes are non-optimal for range queries. In this paper, we integrate replication in conjunction with parallel disk declustering for efficient processing of range queries. We note that replication is largely used in database applications for several purposes like load balancing, fault tolerance and availability of data. We propose theoretical foundations for replicated declustering and propose a class of replicated declustering schemes, periodic allocations, which are shown to be strictly optimal for a number of disks. We propose a framework for replicated declustering, using a limited amount of replication and provide extensions to apply it on real data, which include arbitrary grids and a large number of disks. Our framework also provides an effective indexing scheme that enables fast identification of data of interest in parallel servers. In addition to optimal processing of single queries, we show that this framework is effective for parallel processing of multiple queries. We present experimental results comparing the proposed replication scheme to other techniques for both single queries and multiple queries, on synthetic and real data sets.