ppxscal/embedding_network huggingface dataset:
Plan-based complex event detection across distributed sources
Authors: Mert Akdere, Uǧur Çetintemel, Nesime Tatbul
Venue: Proceedings of the VLDB Endowment (2008)

Complex Event Detection (CED) is emerging as a key capability for many monitoring applications such as intrusion detection, sensor-based activity & phenomena tracking, and network monitoring. Existing CED solutions commonly assume centralized availability and processing of all relevant events, and thus incur significant overhead in distributed settings. In this paper, we present and evaluate communication efficient techniques that can efficiently perform CED across distributed event sources. Our techniques are plan-based: we generate multi-step event acquisition and processing plans that leverage temporal relationships among events and event occurrence statistics to minimize event transmission costs, while meeting application-specific latency expectations. We present an optimal but exponential-time dynamic programming algorithm and two polynomial-time heuristic algorithms, as well as their extensions for detecting multiple complex events with common sub-expressions. We characterize the behavior and performance of our solutions via extensive experimentation on synthetic and real-world data sets using our prototype implementation.
Comparison of online social relations in volume vs interaction: a case study of cyworld
Authors: Hyunwoo Chun, Haewoon Kwak, Young-Ho Eom, Yong-Yeol Ahn, Sue Moon, Hawoong Jeong
Venue: Proceedings of the 8th ACM SIGCOMM conference on Internet measurement (2008)

Online social networking services are among the most popular Internet services according to Alexa.com and have become a key feature in many Internet services. Users interact through various features of online social networking services: making friend relationships, sharing their photos, and writing comments. These friend relationships are expected to become a key to many other features in web services, such as recommendation engines, security measures, online search, and personalization issues. However, we have very limited knowledge on how much interaction actually takes place over friend relationships declared online. A friend relationship only marks the beginning of online interaction. Does the interaction between users follow the declaration of friend relationship? Does a user interact evenly or lopsidedly with friends? We venture to answer these questions in this work. We construct a network from comments written in guestbooks. A node represents a user and a directed edge a comments from a user to another. We call this network an activity network. Previous work on activity networks include phone-call networks [34, 35] and MSN messenger networks [27]. To our best knowledge, this is the first attempt to compare the explicit friend relationship network and implicit activity network. We have analyzed structural characteristics of the activity network and compared them with the friends network. Though the activity network is weighted and directed, its structure is similar to the friend relationship network. We report that the in-degree and out-degree distributions are close to each other and the social interaction through the guestbook is highly reciprocated. When we consider only those links in the activity network that are reciprocated, the degree correlation distribution exhibits much more pronounced assortativity than the friends network and places it close to known social networks. The k-core analysis gives yet another corroborating evidence that the friends network deviates from the known social network and has an unusually large number of highly connected cores. We have delved into the weighted and directed nature of the activity network, and investigated the reciprocity, disparity, and network motifs. We also have observed that peer pressure to stay active online stops building up beyond a certain number of friends. The activity network has shown topological characteristics similar to the friends network, but thanks to its directed and weighted nature, it has allowed us more in-depth analysis of user interaction.
Correcting congestion-based error in network telescope's observations of worm dynamics
Authors: Songjie Wei, Jelena Mirkovic
Venue: Proceedings of the 8th ACM SIGCOMM conference on Internet measurement (2008)

Network telescopes have been invaluable for collecting information about dynamics of large-scale worm events. Yet, a telescope's observation may be incomplete due to scan congestion drops, hardware limitations, filtering and presence of NATs, a worm's non-uniform scanning strategy or its short life. We investigate inaccuracies in telescope observations that arise from worm-induced congestion drops of worm scans and show that they may lead to significant underestimates of the number of infectees and their scanning rate. We propose a method to infer worm-induced congestion drops from telescope's observations and use them to accurately estimate global worm dynamics. We apply our methods to CAIDA telescope's observations of Witty worm's spread, and release corrected statistics of worm dynamics for public use.
TDBS: a time division beacon scheduling mechanism for ZigBee cluster-tree wireless sensor networks
Authors: Anis Koubâa, André Cunha, Mário Alves, Eduardo Tovar
Venue: Real-Time Systems (2008)

Synchronization is a challenging and important issue for time-sensitive Wireless Sensor Networks (WSN) since it requires a mutual spatiotemporal coordination between the nodes. In that concern, the IEEE 802.15.4/ZigBee protocols embody promising technologies for WSNs, but are still ambiguous on how to efficiently build synchronized multiple-cluster networks, specifically for the case of cluster-tree topologies. In fact, the current IEEE 802.15.4/ZigBee specifications restrict the synchronization to beacon-enabled (by the generation of periodic beacon frames) star networks, while they support multi-hop networking in mesh topologies, but with no synchronization. Even though both specifications mention the possible use of cluster-tree topologies, which combine multi-hop and synchronization features, the description on how to effectively construct such a network topology is missing. This paper tackles this issue by unveiling the ambiguities regarding the use of the cluster-tree topology and proposing a synchronization mechanism based on Time Division Beacon Scheduling (TDBS) to build cluster-tree WSNs. In addition, we propose a methodology for efficiently managing duty-cycles in every cluster, ensuring the fairest use of bandwidth resources. The feasibility of the TDBS mechanism is clearly demonstrated through an experimental test-bed based on our open-source implementation of the IEEE 802.15.4/ZigBee protocols.
Logical modelling of the role of the Hh pathway in the patterning of the Drosophila wing disc
Authors: Aitor González, Claudine Chaouiya, Denis Thief
Venue: Bioinformatics (2008)

Motivations: The development of most tissues and organs relies on a limited number of signal transduction pathways enabling the coordination of cellular differentiation. A proper understanding of the roles of signal transduction pathways requires the de.nition of formal models capturing the main qualitative features of these patterning processes. This is a challenging task because the underlying processes, diffusion, regulatory modi.cations, reception and sequestration of signalling molecules, transcriptional regulation of target genes, etc. are only partly characterized. In this context, qualitative models can be more readily proposed on the basis of available (molecular) genetic data. But this requires novel computational tools and proper qualitative representations of phenomena such as diffusion or sequestration. To assess the power and limits of a logical formalism in this context, we propose a multi-level model of the multi-cellular network involved in the de.nition of the anterior–posterior boundary during the development of the wing disc of Drosophila melanogaster. The morphogen Hedgehog (Hh) is the inter-cellular signal coordinating this process. It diffuses from the posterior compartment of the disc to activate its pathway in cells immediately anterior to the boundary. In these boundary cells, the Hh gradient induces target genes in distinct domains as a function of the Hh concentration. One target of Hh signalling is the gene coding for the receptor Patched (Ptc), which sequesters Hh and impedes further diffusion, thereby re.ning the boundary. Results: We have delineated a logical model of the patterning process de.ning the cellular anterior–posterior boundary in the developing imaginal disc of Drosophila melanogaster. This model qualitatively accounts for the formation of a gradient of Hh, as well as for the transduction of this signal through a balance between the activatory (CiA) and inhibitory (CiR) products of the gene cubitus interruptus (ci). Wild-type and mutant simulations have been carried out to assess the coherence of the model with experimental data. Interestingly, our computational analysis provides novel insights into poorly understood processes such as the regulation of Ptc by CiR, the formation of a functional gradient of CiA across boundary cells, or yet functional En differences between anterior and posterior cells. In conclusion, our model analysis demonstrates the.exibility of the logical formalism, enabling consistent qualitative representation of diffusion, sequestration and post-transcriptional regulatory processes within and between neighbouring cells. Availability: An XML.le containing the proposed model together with annotations can be downloaded from our website ( http://gin.univ-mrs.fr/GINsim/), along with GINsim, a logical modelling and simulation software freely available to academic groups. Contact: thieffry@tagc.univ-mrs.fr
Census and survey of the visible internet
Authors: John Heidemann, Yuri Pradkin, Ramesh Govindan, Christos Papadopoulos, Genevieve Bartlett, Joseph Bannister
Venue: Proceedings of the 8th ACM SIGCOMM conference on Internet measurement (2008)

Prior measurement studies of the Internet have explored traffic and topology, but have largely ignored edge hosts. While the number of Internet hosts is very large, and many are hidden behind firewalls or in private address space, there is much to be learned from examining the population of visible hosts, those with public unicast addresses that respond to messages. In this paper we introduce two new approaches to explore the visible Internet. Applying statistical population sampling, we use censuses to walk the entire Internet address space, and surveys to probe frequently a fraction of that space. We then use these tools to evaluate address usage, where we find that only 3.6% of allocated addresses are actually occupied by visible hosts, and that occupancy is unevenly distributed, with a quarter of responsive /24 address blocks (subnets) less than 5% full, and only 9% of blocks more than half full. We show about 34 million addresses are very stable and visible to our probes (about 16% of responsive addresses), and we project from this up to 60 million stable Internet-accessible computers. The remainder of allocated addresses are used intermittently, with a median occupancy of 81 minutes. Finally, we show that many firewalls are visible, measuring significant diversity in the distribution of firewalled block size. To our knowledge, we are the first to take a census of edge hosts in the visible Internet since 1982, to evaluate the accuracy of active probing for address census and survey, and to quantify these aspects of the Internet.
Online generation of scene descriptions in urban environments
Authors: Ingmar Posner, Derik Schroeter, Paul Newman
Venue: Robotics and Autonomous Systems (2008)

The ability to extract a rich set of semantic workspace labels from sensor data gathered in complex environments is a fundamental prerequisite to any form of semantic reasoning in mobile robotics. In this paper, we present an online system for the augmentation of maps of outdoor urban environments with such higher-order, semantic labels. The system employs a shallow supervised classification hierarchy to classify scene attributes, consisting of a mixture of 2D/3D geometric and visual scene information, into a range of different workspace classes. The union of classifier responses yields a rich, composite description of the local workspace. We present extensive experimental results, using two large urban data sets collected by our research platform.
Changes in fluctuation waves in coherent airflow structures with input perturbation
Authors: Osama A. Marzouk
Venue: WSEAS Transactions on Signal Processing (2008)

We predict the development and propagation of the fluctuations in a perturbed ideally-expanded air jet. A non-propagating harmonic perturbation in the density, axial velocity, and pressure is introduced at the inflow with different frequencies to produce coherent structures in the airflow, which are synchronized with the applied frequency. Then, the fluctuations and acoustic fields are predicted for each frequency by integrating the axisymmetric linearized Euler equations. We investigate the effect of the perturbation frequency on different characteristics of the pressure and velocity waves. The perturbation frequency can be used to alter the propagation pattern and intensity of the waves and mitigate the noise levels at certain zones.
Tailoring Taxonomies for Efficient Text Categorization and Expert Finding
Authors: R. Wetzker, W. Umbrath, L. Hennig, C. Bauckhage, T. Alpcan, F. Metze
Venue: Proceedings of the 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Volume 03 (2008)

Automatic content categorization by means of taxonomies is a powerful tool for information retrieval and search technologies as it improves the accessibility of data both for humans and machines. While research on automatic categorization has mainly focused on the problem of classifier design, hardly any effort has been spent on the optimization of the taxonomy size itself. However, taxonomy tailoring may significantly improve computational efficiency and scalability of modern retrieval systems where taxonomies often consist of tens of thousands of non-uniformly distributed categories. In this paper we demonstrate empirically that small subtrees of a taxonomy already enable reliable categorization. We compare several measures for the optimal selection of sub-taxonomies and investigate to what ex-tent a reduction affects the classification quality. We consider applications in classical document categorization and in the upcoming area of expert finding and report corresponding results obtained from experiments with standard benchmark data.
Numerical experiments with universal barrier functions for cones of Chebyshev systems
Authors: L. Faybusovich, T. Mouktonglang, T. Tsuchiya
Venue: Computational Optimization and Applications (2008)

Based on previous explicit computations of universal barrier functions, we describe numerical experiments for solving certain classes of convex optimization problems. The comparison is given of the performance of the classical affine-scaling algorithm with the similar algorithm built upon the universal barrier function.
Using a strategy-aligned fuzzy competitive analysis approach for market segment evaluation and selection
Authors: Chin-Wen Ou, Shuo-Yan Chou, Yao-Hui Chang
Venue: Expert Systems with Applications: An International Journal (2009)

This study applies Five Forces Analysis to evaluate and select market segments for international business using a strategy-aligned fuzzy approach. An illustration segment evaluation procedure is used to demonstrate that our procedure is an effective quantification approach for integrating five forces, generic strategies and marketing information in a group decision-making process. The final decision-maker (DM) synthesizes the total crisp scores of individual alternatives by choosing judgmental coefficients @l based on individual attitude towards core business competitiveness and market risks to accommodate differences among market segments to the specific environment with a better understanding of the decision problem and individual decision-making behavior. In the illustration presented here, the final solution is then obtained by identifying the best market segment for further development and negotiation.
Sediment facies classification of a sandy shoreline by means of airborne imaging spectroscopy
Authors: B. Deronde, P. Kempeneers, R. Houhuys, J. -P. Henriet, V. Van Lancker
Venue: International Journal of Remote Sensing (2008)

Airborne imaging spectroscopy data (AISA Eagle and HyMap) were applied to classify the sediments of a sandy beach in seven sand type classes. On the AISA-Eagle data, several classification strategies were tried out and compared with each other. The best classification results were obtained applying a linear discriminant classifier (LDC) in combination with feature selection based on sequential floating forward search (SFFS). The statistical LDC was used in a multiple binary approach. In the first step, the original bands were used in the classification, but transformation of the bands to wavelet coefficients enhanced the accuracy obtained. The combination of LDC with SFFS resulted in an overall accuracy of 82% (using three wavelet coefficients). Replacing the LDC with the non-statistical SAM algorithm reduced the overall accuracy to 74% (using all bands or wavelet coefficients). When applying LDC, the optimal number of bands/wavelet coefficients to be used was defined: using more than two bands or three wavelet coefficients did not result in a higher classification accuracy. Finally, the HyMap data, featuring 126 bands in the VNIR-SWIR range, were used to demonstrate that the VNIR range outperforms the SWIR range for this application.
Mechanical stabilisation and design optimisation of masks for stencil lithography: Numerical approach and experimental validation
Authors: Maryna Lishchynska, Marc A. F. van den Boogaart, Veronica Savu, J. C. Greer, Juergen Brugger
Venue: Microelectronic Engineering (2008)

This paper addresses mask deformation phenomenon that frequently occurs but is highly undesirable in stencil lithography. Previously, a technique for mechanical stabilisation of stencils was proposed [M.A.F. van den Boogaart, et al., Corrugated membranes for improved pattern definition with micro/nanostencil lithography, Sensors Actuators A 130-131 (2006) 568-574] and successfully validated for simple cantilever-like designs. In present work, the numerical approach to designing optimal geometry of stabilisation structures incorporated onto stencils is applied to complex experimental stencil designs and is validated both numerically and experimentally. Two types of stencil support structures are considered, namely corrugation (hollow rims) and solid silicon rims. Results confirm the effectiveness of the approach and show that up to a 94.5% reduction in stencil deformation with a corresponding improvement in reducing deposited pattern blurring can be achieved. Additionally, design guidelines for the optimal geometries of mechanically stabilised stencils are established. These guidelines can be applied to other types of mechanically unstable structures in need of stiffening to increase their resistance to deformation and improve critical performance characteristics.
Stochastic modeling western paintings for effective classification
Authors: Jialie Shen
Venue: Pattern Recognition (2009)

As one of the most important cultural heritages, classical western paintings have always played a special role in human live and been applied for many different purposes. While image classification is the subject of a plethora of related publications, relatively little attention has been paid to automatic categorization of western classical paintings which could be a key technique of modern digital library, museums and art galleries. This paper studies automatic classification on large western painting image collection. We propose a novel framework to support automatic classification on large western painting image collections. With this framework, multiple visual features can be integrated effectively to improve the accuracy of identification process significantly. We also evaluate our method and its competitors based on a large image collection. A careful study on the empirical results indicates the approach enjoys great superiority over the state-of-the-art approaches in different aspects.
Compression and distribution of panoramic videos utilising MPEG-7-based image registration
Authors: Andrzej Glowacz, Michał Grega, Piotr Romaniak, Mikołaj Leszczuk, Zdzisław Papir, Ignacy Pardyka
Venue: Multimedia Tools and Applications (2008)

This paper describes an innovative compression method of panoramic images based on MPEG-7 descriptors. The proposed solution employs a detection of a series of individual video frame overlaps in order to produce concatenated panoramic images. The presented method is easy to implement even in simple devices such as low power consuming chipsets installed in remote cameras having limited power supplies. Under subjective tests it has been proved that the concatenation method allows for achieving lower transmission rates while sustaining picture quality.
Protection against soft errors in the space environment: A finite impulse response (FIR) filter case study
Authors: J. A. Maestro, P. Reviriego, P. Reyes, O. Ruano
Venue: Integration, the VLSI Journal (2009)

The problem of radiation is a key issue in Space applications, since it produces several negative effects on digital circuits. Considering the high reliability expected in these systems, many techniques have been proposed to mitigate these effects. However, traditional protection techniques against soft errors, like Triple Modular Redundancy (TMR) or EDAC codes (for example Hamming), normally result in a significant area and power overhead. In this paper we propose a specific technique to protect digital finite impulse response (FIR) filters applying the ''system knowledge''. This means to study and use the singularities in their structure in order to provide effective protection with minimal area and power. The results obtained in the experimental process have been compared with the protection offered by TMR and Hamming codes, in order to prove the quality of the proposed solution.
Analyzing and revising data integration schemas to improve their matchability
Authors: Xiaoyong Chai, Mayssam Sayyadian, AnHai Doan, Arnon Rosenthal, Len Seligman
Venue: Proceedings of the VLDB Endowment (2008)

Data integration systems often provide a uniform query interface, called a mediated schema, to a multitude of data sources. To answer user queries, such systems employ a set of semantic matches between the mediated schema and the data-source schemas. Finding such matches is well known to be difficult. Hence much work has focused on developing semi-automatic techniques to efficiently find the matches. In this paper we consider the complementary problem of improving the mediated schema, to make finding such matches easier. Specifically, a mediated schema S will typically be matched with many source schemas. Thus, can the developer of S analyze and revise S in a way that preserves S's semantics, and yet makes it easier to match with in the future? In this paper we provide an affirmative answer to the above question, and outline a promising solution direction, called mSeer. Given a mediated schema S and a matching tool M, mSeer first computes a matchability score that quantifies how well S can be matched against using M. Next, mSeer uses this score to generate a matchability report that identifies the problems in matching S. Finally, mSeer addresses these problems by automatically suggesting changes to S (e.g., renaming an attribute, reformatting data values, etc.) that it believes will preserve the semantics of S and yet make it more amenable to matching. We present extensive experiments over several real-world domains that demonstrate the promise of the proposed approach.