ppxscal/embedding_network huggingface dataset:
On the Nyström Method for Approximating a Gram Matrix for Improved Kernel-Based Learning
Authors: Petros Drineas, Michael W. Mahoney
Venue: The Journal of Machine Learning Research (2005)

A problem for many kernel-based methods is that the amount of computation required to find the solution scales as O(n3), where n is the number of training examples. We develop and analyze an algorithm to compute an easily-interpretable low-rank approximation to an n × n Gram matrix G such that computations of interest may be performed more rapidly. The approximation is of the form ~Gk = CWk+CT, where C is a matrix consisting of a small number c of columns of G and Wk is the best rank-k approximation to W, the matrix formed by the intersection between those c columns of G and the corresponding c rows of G. An important aspect of the algorithm is the probability distribution used to randomly sample the columns; we will use a judiciously-chosen and data-dependent nonuniform probability distribution. Let ||·||2 and ||·||F denote the spectral norm and the Frobenius norm, respectively, of a matrix, and let Gk be the best rank-k approximation to G. We prove that by choosing O(k/&#x3B5;4) columns||G-CWk+CT||ξ ≤ ||G-Gk||ξ + &#x3B5; Σi=1n Gii2 ,both in expectation and with high probability, for both ξ = 2, F, and for all k: 0 ≤ k ≤ rank(W). This approximation can be computed using O(n) additional space and time, after making two passes over the data from external storage. The relationships between this algorithm, other related matrix decompositions, and the Nyström method from integral equation theory are discussed.
Multimodal approach to measuring excitement in video
Authors: A. Hanjalic
Venue: Proceedings of the 2003 International Conference on Multimedia and Expo - Volume 1 (2003)

We present in this paper an approach to mimic the excitement that is evoked in a user while watching a video. The proposed approach is meant to enhance user's comfort when dealing with large amount of broadcasted digital television data reaching his home. For this reason, we deliberately avoid using any sensors placed on users: the simulation of user excitement is based here solely on cues that are available in the digital video stream, and that can be extracted by using standard audio and video processing tools as well as by observing the way video is edited. Relation between the extracted features and evoked excitement is drawn partly from psycho-physiological research and partly from analyzing the video generation practice. Our methodology is generic and can be employed broadly in the process of video abstraction and for revealing the affective characteristics of video content.
It's all about the concept...
Authors: Jonathan Arnowitz, Elizabeth Dykstra-Erickson
Venue: interactions (2006)

How can a design review be conducted on static interfaces? What constitutes good design?
Visual Keyword-based Image Retrieval using Latent Semantic Indexing, Correlation-enhanced Similarity Matching and Query Expansion in Inverted Index
Authors: Md. Mahmudur Rahman, Bipin C. Desai, Prabir Bhattacharya
Venue: Proceedings of the 10th International Database Engineering and Applications Symposium (2006)

This paper presents an image retrieval framework with scalable image representation and inverted file-based indexing by incorporating automatically generated visual keywords. A codebook of visual keywords is implemented adopting a self-organizing map (SOM)-based vector quantization on the feature space of segmented image regions. The codebook is utilized to represent images by calculating the keyword statistics in the individual images as well as in the collection as a whole. To reduce the dimensionality of the sparse feature vector, latent semantic indexing technique is applied and a similarity matching function is proposed by exploiting the correlation between visual keywords. A query expansion strategy is also proposed in the inverted index based on the topology preserving structure of the SOM. Experimental results over a collection of 5000 general photographic images demonstrate the efficiency and effectiveness of the proposed approach compared to the low-level histogram-based approaches.
Agent software comprehension: explaining agent behavior
Authors: K. Suzanne Barber
Venue:  (2005)

It is important for designers, developers, and end-users to comprehend (or explain) why a software agent acts in a particular way when situated in its operating environment. Comprehending agent behaviors in an agent-based system is a challenging task due to environmental uncertainty and the dynamics and multitude of agent interactions, which must be captured, processed, and analyzed by the human user. While traditional software comprehension answers "what is happening in the implementation?", this research takes a step further to facilitate comprehension by answering "why is the behavior happening in the implementation?". To explain agent behaviors in the implemented system, this research takes the model-checking approach for representing abstracted software behavior and the reverse engineering approach for verifying the expected behavior model against the implementation's actual behavior, while assimilating the terminology and framework from abductive reasoning. This research empirically shows that maintaining accurate background knowledge of how the implementation is expected to behave is crucial in generating accurate explanations of agent behavior. The resulting Tracing Method and accompanying Tracer Tool build on ideas from existing approaches and extend the state-of-the-art to better assist human users (of various skill levels) in comprehending agent-based software by automating many reasoning tasks. The Tracing Method is applied to two domains to demonstrate the capabilities of the Tracer Tool in (1) suggesting background knowledge updates, (2) interpreting actual behaviors from implementation executions, and (3) explaining observed agent behaviors. This research aims to help designers who want to improve agent behavior; developers who need to debug and verify agent behavior; and end-users who want to comprehend agent behaviors.
2005 Special issue: Hippocampal mechanisms for the context-dependent retrieval of episodes
Authors: Michael E. Hasselmo, Howard Eichenbaum
Venue: Neural Networks (2005)

Behaviors ranging from delivering newspapers to waiting tables depend on remembering previous episodes to avoid incorrect repetition. Physiologically, this requires mechanisms for long-term storage and selective retrieval of episodes based on the time of occurrence, despite variable intervals and similarity of events in a familiar environment. Here, this process has been modeled based on the physiological properties of the hippocampal formation, including mechanisms for sustained activity in entorhinal cortex and theta rhythm oscillations in hippocampal subregions. The model simulates the context-sensitive firing properties of hippocampal neurons including trial-specific firing during spatial alternation and trial by trial changes in theta phase precession on a linear track. This activity is used to guide behavior, and lesions of the hippocampal network impair memory-guided behavior. The model links data at the cellular level to behavior at the systems level, describing a physiologically plausible mechanism for the brain to recall a given episode which occurred at a specific place and time.
Finding "Who Is Talking to Whom" in VoIP Networks via Progressive Stream Clustering
Authors: Olivier Verscheure, Michail Vlachos, Aris Anagnostopoulos, Pascal Frossard, Eric Bouillet, Philip S. Yu
Venue: Proceedings of the Sixth International Conference on Data Mining (2006)

Technologies that use the Internet network to deliver voice communications have the potential to reduce costs and improve access to communications services around the world. However, these new technologies pose several challenges in terms of confidentiality of the conversations and anonymity of the conversing parties. Call authentication and encryption techniques provide a way to protect confidentiality, while anonymity is typically preserved by an anonymizing service (anonymous call). This work studies the feasibility of revealing pairs of anonymous and encrypted conversing parties (caller/callee pair of streams) by exploiting the vulnerabilities inherent to VoIP systems. In particular, by exploiting the aperiodic inter-departure time of VoIP packets, we can trivialize each VoIP stream into a binary time-series. We first define a simple yet intuitive metric to gauge the correlation between two VoIP binary streams. Then we propose an effective technique that progressively pairs conversing parties with high accuracy and in a limited amount of time. Our metric and method are justified analytically and validated by experiments on a very large standard corpus of conversational speech. We obtain impressively high pairing accuracy that reaches 97% after 5 minutes of voice conversations.
Revlex-initial 0/1-polytopes
Authors: Rafael Gillmann, Volker Kaibel
Venue: Journal of Combinatorial Theory Series A (2006)

We introduce revlex-initial O/1-polytopes as the convex hulls of reverse-lexicographically initial subsets of 0/1-vectors. These polytopes are special knapsack-polytopes. It turns out that they have remarkable extremal properties. In particular, we use these polytopes in order to prove that the minimum numbers gnfac(d, n) of facets and the minimum average degree gavdeg(d, n) of the graph of a d-dimensional 0/1-polytope with n vertices satisfy gnfac(d, n) ≤ 3d and gavdeg(d, n) ≤ d + 4. We furthermore show that, despite the sparsity of their graphs, revlex-initial 0/1-polytopes satisfy a conjecture due to Mihail and Vazirani, claiming that the graphs of 0/1-polytopes have edge-expansion at least one.
Exploit hijacking: side effects of smart defenses
Authors: Costin Raiciu, Mark Handley, David S. Rosenblum
Venue: Proceedings of the 2006 SIGCOMM workshop on Large-scale attack defense (2006)

Recent advances in the defense of networked computers use instrumented binaries to track tainted data and can detect attempted break-ins automatically. These techniques identify how the transfer of execution to the attacker takes place, allowing the automatic generation of defenses. However, as with many technologies, these same techniques can also be used by the attackers: the information provided by detectors is accurate enough to allow an attacker to create a new worm using the same vulnerability, hijacking the exploit. Hijacking changes the threat landscape by pushing attacks to extremes (targeting selectively or creating a rapidly spreading worm), and increasing the requirements for automatic worm containment mechanisms. In this paper, we show that hijacking is feasible for two categories of attackers: those running detectors and those using Self-Certifying Alerts, a novel mechanism proposed by Costa et al. for end-to-end worm containment. We provide a discussion of the effects of hijacking on the threat landscape and list a series of possible countermeasures.
Neural Correlates of Retrieval Orientation: Effects of Study&ndash;Test Similarity
Authors: Michael Hornberger, Alexa M. Morcom, Michael D. Rugg
Venue: Journal of Cognitive Neuroscience (2004)

ERPs elicited by correctly classified unstudied items in tests of yes/no recognition memory were used to investigate the neural correlates of retrieval cue processing. Items in Experiment 1 consisted of pictures and their corresponding names, allowing study and test material to be factorially crossed in four separate study&ndash;test cycles. The ERPs elicited by unstudied pictures and words were, in each case, more negative-going when the study material belonged to the alternative rather than the same class of items. These findings demonstrate that previously reported ERP ''retrieval orientation effects'' depend on differences in similarity between study and test items, and not on the form of the sought for material. In Experiments 2a and 2b, study materials were auditory words and pictures, and the test items were visual words. In both experiments, ERPs elicited by unstudied test words were more negative-going when pictures rather than auditory words were the study material. Thus, ERP retrieval orientation effects do not depend on the employment of a copy cue condition. It is proposed that the effects reflect differences in the processing necessary to maximize overlap between cue and memory representations.
Dynamic tracking filters for decomposing nonstationary sinusoidal signals
Authors: A. Rao, R. Kumaresan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1995. on International Conference - Volume 02 (1995)

A procedure to decompose a signal consisting of nonstationary sinusoidal components based on the principles of residual signal analysis is proposed. A tracking unit consisting of an all zero filter (AZF) in cascade with a dynamic tracking filter (DTF) is assigned to each component. While the adaptively varying zeros of the AZF suppresses all interfering neighbors, the DTF captures the slowly varying instantaneous frequency (IF) of the desired component. Our earlier methods improved upon Costas's estimator-predictor filter bank by using a better interfering signal predictor. The alternative procedure described in this paper avoids the use of prediction and is not overly restricted by the number of components. We also show that by using two simple feedback loops (a loop-filter is thus avoided) the tracking information is ensured to be in phase. Finally, the algorithms ability to decompose synthetic signals, speech signals into harmonic partials as well as tracking the formants present in voiced speech segments is illustrated.
New algorithms for array processing using higher order statistics
Authors: T. S. Durrani, A. R. Leyman, J. J. Soraghan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1993. ICASSP-93 Vol 4., 1993 IEEE International Conference on - Volume 04 (1993)

Higher order statistical (HOS) methods for direction of arrival (DOA) estimation in array processing have many advantages over the conventional techniques. The authors introduce a set of algorithms for DOA estimation based on a new class of performance criteria related to the bispectra power of the data. The algorithms are embedded in a generalized framework and applied to narrowband sensor arrays. A precise formulation of the source signal model is given. Conditions are stated on the model and the assumed noise sufficient for a solution to the DOA problem to exist for any set of array outputs in the HOS-domain. The new performance criteria are described in relation to the cumulants of the array. Three new HOS-based algorithms are derived based on this criteria. The computational behavior of each of these is also addressed. Numerical simulation results for the algorithms are presented.
PhotoFOAF: A Community Building Service driven by Socially-Aware Mobile Imaging
Authors: Kristof Thys, Ruben Thys, Kris Luyten, Karin Coninx
Venue: Proceedings of the First International Workshop on Semantic Media Adaptation and Personalization (2006)

Mobile digital photography has become a ubiquitous service: nowadays, nearly every mobile phone is equipped with a camera. This results in huge collections of pictures that are hard to structure and has lead to problems in saving, managing and exchanging digital pictures. Photo- FOAF presents a new approach to mobile imaging, exploiting the social context of a picture as an important part of the metadata. We present an approach that allows users to insert social metadata in pictures while capturing them. The resulting collections of captured pictures can be managed, searched and exchanged more easily by taking benefit of the personal social relevance of a picture. PhotoFOAF implements an end-to-end process to accomplish this and it exploits, enhances and stimulates social relationships between users during all the different steps.
Evaluating Network Processors using NetBench
Authors: Gokhan Memik, William H. Mangione-Smith
Venue: ACM Transactions on Embedded Computing Systems (TECS) (2006)

The Network Processor market is one of the fastest growing segments of the microprocessor industry today. In spite of this increasing market importance, there does not exist a common framework to compare the performance of different Network Processor designs. Our primary goal in this study is to fill this gap by creating the NetBench benchmarking suite. NetBench is designed to represent Network Processor workloads. It contains 11 programs that form 18 different applications. The programs are selected from all levels of packet processing: Small, low-level code fragments as well as large application-level programs are included in the suite. These applications are representative of the Network Processor applications in the market. Using the SimpleScalar simulator to model an ARM processor, we study these programs in detail and compare key characteristics, such as instructions per cycle, instruction distribution, cache behavior, and branch prediction accuracy with the programs from MediaBench. Using statistical analysis, we show that the simulation results for the programs in NetBench have significantly different characteristics than programs in MediaBench. Finally, we present performance measurements from Intel IXP1200 Network Processor to show how NetBench can be utilized.
Regulator problem for linear discrete-time delay systems with Markovian jumping parameters and symmetrical constraints
Authors: N. Daraoui, A. Benzaouia
Venue: International Journal of Systems Science (2006)

In this paper, we investigate the regulation problem for linear discrete-time delay systems with Markovian jumps and constrained control. The constraints used here are of symmetrical inequality type. A sufficient condition of stochastic stability of closed-loop system is derived. We use the positive invariance approach of the common set for all the modes to guarantee the admissibility of the control law. In the case of one mode, we obtain the condition of stability for a linear discrete-time delay system as known in the literature. A numerical example is given to illustrate the theoretic results.
Multi-Aspect Detection of Articulated Objects
Authors: Edgar Seemann, Bastian Leibe, Bernt Schiele
Venue: Proceedings of the 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition - Volume 2 (2006)

A wide range of methods have been proposed to detect and recognize objects. However, effective and efficient multiviewpoint detection of objects is still in its infancy, since most current approaches can only handle single viewpoints or aspects. This paper proposes a general approach for multiaspect detection of objects. As the running example for detection we use pedestrians, which add another difficulty to the problem, namely human body articulations. Global appearance changes caused by different articulations and viewpoints of pedestrians are handled in a unified manner by a generalization of the Implicit Shape Model [5]. An important property of this new approach is to share local appearance across different articulations and viewpoints, therefore requiring relatively few training samples. The effectiveness of the approach is shown and compared to previous approaches on two datasets containing pedestrians with different articulations and from multiple viewpoints.
Assessing spatial navigation tools with instructional hypermedia for cognitive science
Authors: Christine Diehl, Michael Ranney
Venue: Proceedings of the 1996 international conference on Learning sciences (1996)

We investigated the influence of spatial visualization, spatial reasoning, and environmental cognition skills on students' use of instructional hypermedia navigation tools. Forty undergraduate cognitive science students were randomly assigned to one of two hypermedia system conditions: a map-like navigation tool ("spatial" representation) or a menu-like navigation tool ("less spatial"). All students performed a searching activity, then browsed freely through the system. Students then commented on their perceptions of the system and drew concept maps of the contents. Regression analyses indicate that performance with the map-like navigation tool is positively correlated with environmental cognition, whereas performance with the menu-like navigation tool is positively correlated with spatial visualization and reasoning. The general findings suggest that spatial navigation tools should be incorporated into instructional hypermedia with less spatial navigation methods to complement students' spatial cognitive abilities.
Designing Efficient Irregular Networks for Heterogeneous Systems-on-Chip
Authors: Christian Neeb, Norbert Wehn
Venue: Proceedings of the 9th EUROMICRO Conference on Digital System Design (2006)

Networks-on-Chip will serve as the central integration platform in future complex SoC designs, composed of a large number of heterogeneous processing resources. Most researchers advocate the use of traditional regular networks like meshes, tori or trees as architectural templates which gained a high popularity in general-purpose parallel computing. However, most SoC platforms are special-purpose tailored to the domain-specific requirements of their application. They are usually built from a large diversity of heterogeneous components which communicate in a very specific, mostly irregular way. In this work, we propose a methodology for the design of customized irregular networks-on-chip, called INoC. We take advantage of a priori knowledge of the applications communication characteristic to generate an optimized network topology and routing algorithm. We show that customized irregular networks are clearly superior to traditional regular architectures in terms of performance at comparable implementation costs for irregular workloads. Even more, they inherently offer true scalability and expansibility which can normally not be accomplished by traditional approaches.
Engagement with Online Curriculum Materials and the Course Test Performance of Medical Students
Authors: Tyrone Donnon, Claudio Violato, Jean-Gaston DesCoteaux
Venue: Proceedings of the Eighth IEEE International Symposium on Multimedia (2006)

The purpose of this study was to explore the use of an online curriculum system by first year medical students and its relationship to academic performance. The course test performance and online use of course based materials and resources were monitored for 114 first year medical students on a continuous basis from August 15, 2003, to May 31, 2004. Repeated measures of analysis of variance and multiple regression were used to assess differences in use online and test performance. All of the first year medical students showed dramatic fluctuations in online use of curriculum materials dictated by the seven regularly scheduled course examinations. The relationship between online study patterns and examination performance, however, was found not to be statistically significant. In conclusion, the patterns of online use of curriculum materials by first year medical students is not consistent, but varies dramatically as a function of the assessment process.