ppxscal/embedding_network huggingface dataset:
Mortar finite volume element method with Crouzeix--Raviart element for parabolic problems
Authors: Chunjia Bi, Wenbin Chen
Venue: Applied Numerical Mathematics (2008)

In this paper, we consider a semi-discrete mortar finite volume element method for two-dimensional parabolic problems. This method is based on the mortar Crouzeix-Raviart non-conforming finite element space. It is proved that the mortar finite volume element approximations derived are convergent with the optimal order in the H^1- and L^2-norms. Numerical experiments are presented to illustrate the theoretical results.
Ugo Montanari and Friends
Authors: Fabio Gadducci
Venue: Concurrency, Graphs and Models: Essays Dedicated to Ugo Montanari on the Occasion of His 65th Birthday (2008)

Last, but by no means least... This section covers the most important facet of Ugo's personality, namely, his tireless efforts in building national and international relationships, in order to foster the advance of research. Indeed, a large part of Ugo's time is spent in casting a web of links among people as well as institutions, fostering research collaborations and exchanges of ideas. A facet of his personality Ugo is aware of, as he witnesses in his recent book-interview [11].Consider e.g. the first three contributions of this section, and let us start chauvinistically with the Italian colleague, Angelo Raffaele Meo. Ugo often talks about those five years "lost to his research", where he actively contributed to the shaping of the governmental guidelines for ITC. In the late Seventies, Meo was the chair of the National Program in Computer Sciences for the National Research Council (CNR); Ugo headed one of the three sections of that Program, devoted to Computer Industry. The major subproject of the Program was Campus Net (CNet) Project, lead by Norma Lijtmaer and running from 1979 to 1985. Ugo, Norma and Meo were the driving force behind CNet: the project represented a major focus for Italian ITC, maybe one of the most influential and ambitious among those projects combined into the first Progetto Finalizzato in Informatica sponsored by CNR. Research issues focused on developing the functional specification and implementing prototype versions of distributed systems on local networks. The technical accomplishments were initially spread in a series of technical reports, and the main achievements were collected in a two-volume proceedings of the final symposium [7], held in Pisa in June 24-28, 1985. The presence of a large group of industrial partners, among them Olivetti, had consequences far beyond the scientific assessments of the projects itself, in a booming period for the national industry. Moreover, the project was likely the defining moment for Ugo's interests in concurrency, and one of the key steps in the rise of the whole area in Italy. Some of the outcomes of the project (such as [6], originally a CNet technical report) were later considered pivotal by key people like Robin Milner in the development of nominal calculi. The topic tackled by Meo in his article is maybe far from Ugo's current interests. Nevertheless, let us not forget that Ugo was the coauthor of the first Italian textbook on formal languages and computability [5].
Interacting with Inspectable Bayesian Student Models
Authors: Juan-Diego Zapata-Rivera, Jim E. Greer
Venue: International Journal of Artificial Intelligence in Education (2004)

Inspectable student models focus on the idea of letting students and teachers interact with the representation of the student that the system maintains. Both humans and the system can benefit from this interaction. By externalizing the student model and making it an object for inspection, several representational and interaction issues arise. This paper presents ViSMod (Visualization of Bayesian Student Models) an integrated tool to visualize and inspect distributed Bayesian student models. Using ViSMod, students and teachers can understand, explore, inspect, and modify Bayesian student models. ViSMod offers a practical tool that helps students and teachers to engage in negotiated assessment processes. Student models in ViSMod follow the Bayesian belief net backbone structure proposed by Reye (1996), which describes both cognitive and social aspects of the student. In addition, we report on a usability study of the ViSMod tool and an exploratory study focused on the effects of employing various levels of guidance and support in the way students interact with inspectable Bayesian student models.
Asymptotic behavior of exchange ratio in exchange Monte Carlo method
Authors: Kenji Nagata, Sumio Watanabe
Venue: Neural Networks (2008)

The exchange Monte Carlo (EMC) algorithm is well known as being an improvement on the Markov Chain Monte Carlo method. Although it has been shown to be effective in many different contexts, the mathematical foundation of the EMC method has not yet been established. In this paper, we derive the asymptotic behavior of the symmetrized Kullback divergence and the exchange ratio, which is the acceptance ratio of the exchange process for the EMC method. In addition, based on these derived results, we propose optimal settings for the EMC method.
Backup path set selection in ad hoc wireless network using link expiration time
Authors: Arash Dana, Ahmad Khadem Zadeh, Seyed Ali Sadat Noori
Venue: Computers and Electrical Engineering (2008)

Topological changes in mobile ad hoc networks frequently render routing paths unusable. Such recurrent path failures have detrimental effects on quality of service. A suitable technique for eliminating this problem is to use multiple backup paths between the source and the destination in the network. Most of the proposed on-demand routing protocols however, build and rely on single route for each data session. Whenever there is a link disconnection on the active route, the routing protocol must perform a path recovery process. This paper proposes an effective and efficient protocol for backup and disjoint path set in an ad hoc wireless network. This protocol converges into a highly reliable path set very fast with no message exchange overhead. The paths selection according to this algorithm is beneficial for mobile ad hoc networks, since it produces a set of backup paths with much higher reliability. Simulations are conducted to evaluate the performance of our algorithm in terms of route numbers in the path set and its reliability. In order to acquire link reliability estimates, we use link expiration time (LET) between each two nodes. In another experiment, we save the LET of entire links in the ad hoc network during a specific time period, then use them as a data base for predicting the probability of proper operation of links. Links reliability obtains from LET. Prediction is done by using a multi-layer perceptron (MLP) network which is trained with error back-propagation error algorithm. Experimental results show that the MLP net can be a good choice to predict the reliability of the links between the mobile nodes with more accuracy.
Alkali-metal clusters encapsulated into fullerenes: Computations on Li$_{x}$@C$_{60}$
Authors: Zdeněk Slanina, Filip Uhlík, Shyi-Long Lee, Ludwik Adamowicz, Shigeru Nagase
Venue: Journal of Computational Methods in Sciences and Engineering (2007)

Li@C$_{60}$ and Li@C$_{70}$ can be now produced by the low-energy bombardment method in bulk amounts and thus, their computations at higher levels of theory are also of interest. In the report, the computations are carried out on Li@C$_{60}$, Li$_2$@C$_{60}$ and Li$_3$@C$_{60}$with the B3LYP density-functional treatment in the standard 3-21G and 6-31G* basis sets. In all three species Li atoms exhibit non-central locations relatively close to the cage. The computed energetics suggests that Li$_x$@C$_{60}$ species could be produced for several small x values if the Li pressure is enhanced sufficiently. This type of metallofullerenes also belongs among potential candidate agents for nanoscience applications including molecular electronics.
Bridged Refinement for Transfer Learning
Authors: Dikan Xing, Wenyuan Dai, Gui-Rong Xue, Yong Yu
Venue: Proceedings of the 11th European conference on Principles and Practice of Knowledge Discovery in Databases (2007)

There is usually an assumption in traditional machine learning that the training and test data are governed by the same distribution. This assumption might be violated when the training and test data come from different time periods or domains. In such situations, traditional machine learning methods not aware of the shift of distribution may fail. This paper proposes a novel algorithm, namely bridged refinement, to take the shift into consideration. The algorithm corrects the labels predicted by a shift-unaware classifier towards a target distribution and takes the mixture distribution of the training and test data as a bridge to better transfer from the training data to the test data. In the experiments, our algorithm successfully refines the classification labels predicted by three state-of-the-art algorithms: the Support Vector Machine, the naïve Bayes classifier and the Transductive Support Vector Machine on eleven data sets. The relative reduction of error rates is about 50% in average.
Non-negative Increment Feature Detection of the Traffic Throughput for Early DDoS Attack
Authors: Ying Huang, Huizhong Sun, H. Jonathan Chao, Xiong Chao
Venue: Proceedings of the 2007 Third International IEEE Conference on Signal-Image Technologies and Internet-Based System (2007)

One of the major threats to cyber security is Distributed Denial of Service (DDoS) attacks. In this paper, we reveal the non-negative and cumulative increment effect of DDoS traffic throughput that is the feature accurately distinguished DDoS attacking traffic from normal flash crowd traffic. Our scheme can detect a DDoS attack in its early stages based on these feature. It can differentiate DDoS from flash crowd traffic effectively even if DDoS is potential. This scheme detects DDoS attacks with on-line and distributed characteristics. Simulation shows the algorithm's validity and accuracy.
Sharing courses: the CS & IT capstone experience
Authors: Paul Mullins, Daniel Borsch
Venue: Proceedings of the 9th ACM SIGITE conference on Information technology education (2008)

This paper provides a comparison of the curricular recommendations for IT and a CS course in software engineering, including the specific topics covered in a recent class. The evolution of the semester project for this class, a web-based interface to a multimedia database for instructors and students, created in part by end users, is described and correlations are drawn to the IT curriculum recommendations. The course is proposed as appropriate, in general, as an elective in the IT curriculum that serves as a companion to the IT capstone.
A characterization of interval-valued residuated lattices
Authors: B. Van Gasse, C. Cornelis, G. Deschrijver, E. E. Kerre
Venue: International Journal of Approximate Reasoning (2008)

As is well-known, residuated lattices (RLs) on the unit interval correspond to left-continuous t-norms. Thus far, a similar characterization has not been found for RLs on the set of intervals of [0,1], or more generally, of a bounded lattice L. In this paper, we show that the open problem can be solved if it is restricted, making only a few simple and intuitive assumptions, to the class of interval-valued residuated lattices (IVRLs). More specifically, we derive a full characterization of product and implication in IVRLs in terms of their counterparts on the base RL. To this aim, we use triangle algebras, a recently introduced variety of RLs that serves as an equational representation of IVRLs.
Graph representations of molecular similarity measures based on topological resolution
Authors: Paul G. Mezey
Venue: Journal of Computational Methods in Sciences and Engineering (2005)

Graph representations of families of topologies are introduced for a concise description of hierarchies of topologies involved in Resolution-Based Similarity Measures of molecules within a topological context. In the general case of partially ordered families of topological spaces involved in the characterization of similarity relations within large families of molecules, for example, those in pharmaceutical databases, these graphs provide a global characterization of the databases. The newly introduced graph representations also serve as tools for compatibility assessment for database mergers, for example, if the accumulated data in the information systems of two pharmaceutical companies are combined.
The Deviation Constraint
Authors: Pierre Schaus, Yves Deville, Pierre Dupont, Jean-Charles Régin
Venue: Proceedings of the 4th international conference on Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems (2007)

This paper introduces DEVIATION, a soft global constraint to obtain balanced solutions. A violation measure of the perfect balance can be defined as the L p norm of the vector variables minus their mean. SPREAD constraints the sum of square deviations to the mean [5,7] i.e. the L 2 norm. The L 1 norm is considered here. Neither criterion subsumes the other but the design of a propagator for L 1 is simpler. We also show that a propagator for DEVIATION runs in $\mathcal{O}(n)$ (with respect to the number of variables) against $\mathcal{O}(n^2)$ for SPREAD.
Audio Signal Analysis: An Application to Wolf Population Counting
Authors: B. Dugnol, C. Fernández, G. Galiano, J. Velasco
Venue: Proceedings of the 2007 Third International IEEE Conference on Signal-Image Technologies and Internet-Based System (2007)

We investigate the use of signal and image theory based algorithms to estimate the number of individuals within a wolf pack howling in a given field recording, as a counting alternative to the traditional trace collecting methodologies. We, first, apply a noise-reduction signal-enhancement technique based on the numerical solving of a suitable partial differential equation acting on the spectrogram. Then, assuming that the wolves chorus may be modelled as an addition of linear chirps, we use the quadratic energy distribution corresponding to the Chirplet Transform of the signal to produce estimates of the corresponding instantaneous frequencies, chirp-rates and amplitudes at each instant of the recording. We finally establish suitable criteria to decide how such estimates are connected in time.
Bounds on Inter-carrier Interference Power of OFDM in a Gaussian Scattering Channel
Authors: Khoa N. Le
Venue: Wireless Personal Communications: An International Journal (2008)

This letter derives the upper and lower bounds on inter-carrier interference power P ICI of Orthogonal Frequency Division Multiplexing (OFDM) in a Gaussian scattering channel. The bounds are computed as functions of f d T s product of the maximum Doppler spread f d and symbol duration T s , ¿ frequency tracking and ¿ mobile travelling direction. Insightful discussions on the characteristics of P ICI are given. Future work is also outlined.
Scalable approximate query processing with the DBO engine
Authors: Chris Jermaine, Subramanian Arumugam, Abhijit Pol, Alin Dobra
Venue: ACM Transactions on Database Systems (TODS) (2008)

This article describes query processing in the DBO database system. Like other database systems designed for ad hoc analytic processing, DBO is able to compute the exact answers to queries over a large relational database in a scalable fashion. Unlike any other system designed for analytic processing, DBO can constantly maintain a guess as to the final answer to an aggregate query throughout execution, along with statistically meaningful bounds for the guess's accuracy. As DBO gathers more and more information, the guess gets more and more accurate, until it is 100&percnt; accurate as the query is completed. This allows users to stop the execution as soon as they are happy with the query accuracy, and thus encourages exploratory data analysis.
Faster Than Uppaal?
Authors: Sebastian Kupferschmid, Martin Wehrle, Bernhard Nebel, Andreas Podelski
Venue: Proceedings of the 20th international conference on Computer Aided Verification (2008)

It is probably very hard to develop a new model checker that is faster than Uppaal for verifying (correct) timed automata. In fact, our tool Mcta does not even try to compete with Uppaal in this (i.e., Uppaal's) arena. Instead, Mcta is geared towards analyzing incorrect specifications of timed automata. It returns (shorter) error traces faster.
A Multi-robot Surveillance System Simulated in Gazebo
Authors: E. Folgado, M. Rincón, J. R. Álvarez, J. Mira
Venue: Proceedings of the 2nd international work-conference on Nature Inspired Problem-Solving Methods in Knowledge Engineering: Interplay Between Natural and Artificial Computation, Part II (2007)

A special kind of surveillance problem is the monitoring of wide enclosed areas with difficult access and changing environments. The characteristics of this kind of problem recommend a solution based on a multi-agent system, where several robots cooperate to solve the problem. A multi-robot system for surveillance in these kinds of environments has been designed and simulated on the Gazebo 3D simulator. Typical surveillance tasks are simulated and experimental results are shown.
Security of Improvement on Methods for Protecting Password Transmission
Authors: Chou-Chen Yang, Ting-Yi Chang, Min-Shiang Hwang
Venue: Informatica (2003)

Recently, Tseng et al. proposed an improvement on Peyravian and Zunic's protected password transmission scheme and protected changing scheme to remove some security flaws. However, as we will point out in this paper, any adversary can intercept the request for changing the password sent by a legal user and modify it with a wrong password. Furthermore, we shall also propose an improved version of their protected password changing scheme to help it out of the trouble.
SkyGraph: An Algorithm for Important Subgraph Discovery in Relational Graphs
Authors: Apostolos N. Papadopoulos, Apostolos Lyritsis, Yannis Manolopoulos
Venue: Proceedings of the 2008 European Conference on Machine Learning and Knowledge Discovery in Databases - Part I (2008)

Graph mining is gaining importance due to the numerous applications that rely on graph-based data. Some example applications are: (i) analysis of microarray data in bioinformatics, (ii) pattern discovery in social networks, (iii) analysis of transportation networks, (iv) community discovery in Web data. Existing pattern discovery approaches operate by using simple constraints on the mined patterns. For example, given a database of graphs, a typical graph mining task is to report all subgraphs that appear in at least s graphs, where s is the frequency support threshold. In other cases, we are interested in the discovery of dense or highly-connected subgraphs. In such a case, a threshold is defined for the density or the connectivity of the returned patterns. Other constraints may be defined as well, towards restricting the number of mined patterns. There are three important limitations with this approach: (i) there is an on-off decision regarding the eligibility of patterns, i.e., a pattern either satisfies the constraints or not, (ii) in the case where the constraints are very strict we risk an empty answer or an answer with only a few patterns, and (iii) in the case where the constraints are too weak the number of patterns may be huge.
Hybrid Tag Anti-collision Algorithms in RFID Systems
Authors: Jae-Dong Shin, Sang-Soo Yeo, Tai-Hoon Kim, Sung Kwon Kim
Venue: Proceedings of the 7th international conference on Computational Science, Part IV: ICCS 2007 (2007)

RFID, Radio Frequency Identification, technology is a contactless automatic identification technology about which a lot of researches and developments are recently progressing. For this RFID technology to be widely spread, the problem of multiple tag identification, which a reader identifies a multiple number of tags in a very short time, has to be solved. So far, several anti-collision algorithms are developed. And those can be largely divided into ALOHA based algorithm and tree based algorithm. In this paper, two new anti-collision algorithms combining the characteristics of these two categories are presented. And the performances of the two algorithms are simulated.
Parallel Ant Colony Optimization for the Quadratic Assignment Problems with Symmetric Multi Processing
Authors: Shigeyoshi Tsutsui
Venue: Proceedings of the 6th international conference on Ant Colony Optimization and Swarm Intelligence (2008)

Recently symmetric multi processing (SMP) has become available at a reasonable cost. In this paper, we propose several types of parallel ACO algorithms with SMP for solving the quadratic assignment problem (QAP). These models include the master-slave models and the island models. We evaluated each parallel algorithm with a condition that the run time for each parallel algorithm and the base sequential algorithm are the same. The results suggest that using the master-slave model with increased iteration of ACO algorithms is promising in solving QAPs.
Density Elimination and Rational Completeness for First-Order Logics
Authors: Agata Ciabattoni, George Metcalfe
Venue: Proceedings of the international symposium on Logical Foundations of Computer Science (2007)

Density elimination by substitutions is introduced as a uniform method for removing applications of the Takeuti-Titani density rule from proofs in first-order hypersequent calculi. For a large class of calculi, density elimination by this method is guaranteed by known sufficient conditions for cut-elimination. Moreover, adding the density rule to any axiomatic extension of a simple first-order logic gives a logic that is rational complete; i.e., complete with respect to linearly and densely ordered algebras: a precursor to showing that it is a fuzzy logic (complete for algebras with a real unit interval lattice reduct). Hence the sufficient conditions for cut-elimination guarantee rational completeness for a large class of first-order substructural logics.
A Generic Intrusion Detection Game Model in IT Security
Authors: Ioanna Kantzavelou, Sokratis Katsikas
Venue: Proceedings of the 5th international conference on Trust, Privacy and Security in Digital Business (2008)

Intrusion Detection has a central role in every organization's IT Security. However, limitations and problems prevent the commercial spread of Intrusion Detection Systems. This paper presents an attempt to improve Intrusion Detection benefits with the use of Game Theory. A generic intrusion detection game model that reveals the way an IDS interacts with a user is described and examined thoroughly. Moreover, a specific scenario with an internal attacker and an IDS is presented in a normal form game to validate the functioning of the proposed model. Solutions for this game are given as a one shot game as well as an infinitely repeated game.
Dynamic Threshold Public-Key Encryption
Authors: Cécile Delerablée, David Pointcheval
Venue: Proceedings of the 28th Annual conference on Cryptology: Advances in Cryptology (2008)

This paper deals with threshold public-key encryption which allows a pool of players to decrypt a ciphertext if a given threshold of authorized players cooperate. We generalize this primitive to the dynamic setting, where any user can dynamically join the system, as a possible recipient; the sender can dynamically choose the authorized set of recipients, for each ciphertext; and the sender can dynamically set the threshold t for decryption capability among the authorized set. We first give a formal security model, which includes strong robustness notions, and then we propose a candidate achieving all the above dynamic properties, that is semantically secure in the standard model, under a new non-interactive assumption, that fits into the general Diffie-Hellman exponent framework on groups with a bilinear map. It furthermore compares favorably with previous proposals, a.k.a. threshold broadcast encryption, since this is the first threshold public-key encryption, with dynamic authorized set of recipients and dynamic threshold that provides constant-size ciphertexts.