The science papers I've read

Today I read a paper titled “Agent-based Social Psychology: from Neurocognitive Processes to Social Data”

The abstract is:
Moral Foundation Theory states that groups of different observers may rely on partially dissimilar sets of moral foundations, thereby reaching different moral valuations.

The use of functional imaging techniques has revealed a spectrum of cognitive styles with respect to the differential handling of novel or corroborating information that is correlated to political affiliation.

Here we characterize the collective behavior of an agent-based model whose inter individual interactions due to information exchange in the form of opinions are in qualitative agreement with experimental neuroscience data.

The main conclusion derived connects the existence of diversity in the cognitive strategies and statistics of the sets of moral foundations and suggests that this connection arises from interactions between agents.

Thus a simple interacting agent model, whose interactions are in accord with empirical data on conformity and learning processes, presents statistical signatures consistent with moral judgment patterns of conservatives and liberals as obtained by survey studies of social psychology.

Today I read a paper titled “Incremental and Transitive Discrete Rotations”

The abstract is:
A discrete rotation algorithm can be apprehended as a parametric application $f\_\alpha$ from $\ZZ[i]$ to $\ZZ[i]$, whose resulting permutation “looks like” the map induced by an Euclidean rotation.

For this kind of algorithm, to be incremental means to compute successively all the intermediate rotate d copies of an image for angles in-between 0 and a destination angle.

The di scretized rotation consists in the composition of an Euclidean rotation with a discretization; the aim of this article is to describe an algorithm whic h computes incrementally a discretized rotation.

The suggested method uses o nly integer arithmetic and does not compute any sine nor any cosine.

More pr ecisely, its design relies on the analysis of the discretized rotation as a step function: the precise description of the discontinuities turns to be th e key ingredient that will make the resulting procedure optimally fast and e xact.

A complete description of the incremental rotation process is provided, also this result may be useful in the specification of a consistent set of defin itions for discrete geometry.

Today I read a paper titled “Modular Adaptive System Based on a Multi-Stage Neural Structure for Recognition of 2D Objects of Discontinuous Production”

The abstract is:
This is a presentation of a new system for invariant recognition of 2D objects with overlapping classes, that can not be effectively recognized with the traditional methods.

The translation, scale and partial rotation invariant contour object description is transformed in a DCT spectrum space.

The obtained frequency spectrums are decomposed into frequency bands in order to feed different BPG neural nets (NNs).

The NNs are structured in three stages – filtering and full rotation invariance; partial recognition; general classification.

The designed multi-stage BPG Neural Structure shows very good accuracy and flexibility when tested with 2D objects used in the discontinuous production.

The reached speed and the opportunuty for an easy restructuring and reprogramming of the system makes it suitable for application in different applied systems for real time work.

Today I read a paper titled “Relativity as a Consequence of Quantum Entanglement: A Quantum Logic Gate Space Model for the Universe”

The abstract is:
Everything in the Universe is assumed to be compromised of pure reversible quantum Toffoli gates, including empty space itself.

Empty space can be configured into photon or matter gates simply by swapping logic input information with these entities through the phenomenon of quantum mechanical entanglement between photons and empty space Toffoli gates.

The essential difference between empty space, photons and matter gates are the logic input values of their respective Toffoli gates.

Empty space is characterized by an inability for the logic inputs to influence the internal logic state of its Toffoli gates since the control lines are set to logic 0.

Photons and matter are characterized by Toffoli gates where the control lines are set to logic 1 enabling their logic inputs to control their internal logic states allowing for their interaction according to the laws of physics associated with reality.

Photons swapping logic input information with empty space results in the propagation of light.

Photons facilitating the swapping of information between matter and empty space gates leads to the laws of motion including relativity.

This model enables the derivation of many physical laws from purely quantum mechanical considerations including the Heisenberg Uncertainty Principle, the Lorentz transformations of special relativity, and the relationship between relativistic energy and mass.

The model provides a possible explanation for many physical phenomena including dark matter, anti-matter, and an inflationary Universe.

Today I read a paper titled “A Wavelet-Based Digital Watermarking for Video”

The abstract is:
A novel video watermarking system operating in the three dimensional wavelet transform is here presented.

Specifically the video sequence is partitioned into spatio temporal units and the single shots are projected onto the 3D wavelet domain.

First a grayscale watermark image is decomposed into a series of bitplanes that are preprocessed with a random location matrix.

After that the preprocessed bitplanes are adaptively spread spectrum and added in 3D wavelet coefficients of the video shot.

Our video watermarking algorithm is robust against the attacks of frame dropping, averaging and swapping.

Furthermore, it allows blind retrieval of embedded watermark which does not need the original video and the watermark is perceptually invisible.

The algorithm design, evaluation, and experimentation of the proposed scheme are described in this paper.

Today I read a paper titled “Multi-camera Realtime 3D Tracking of Multiple Flying Animals”

The abstract is:
Automated tracking of animal movement allows analyses that would not otherwise be possible by providing great quantities of data.

The additional capability of tracking in realtime – with minimal latency – opens up the experimental possibility of manipulating sensory feedback, thus allowing detailed explorations of the neural basis for control of behavior.

Here we describe a new system capable of tracking the position and body orientation of animals such as flies and birds.

The system operates with less than 40 msec latency and can track multiple animals simultaneously.

To achieve these results, a multi target tracking algorithm was developed based on the Extended Kalman Filter and the Nearest Neighbor Standard Filter data association algorithm.

In one implementation, an eleven camera system is capable of tracking three flies simultaneously at 60 frames per second using a gigabit network of nine standard Intel Pentium 4 and Core 2 Duo computers.

This manuscript presents the rationale and details of the algorithms employed and shows three implementations of the system.

An experiment was performed using the tracking system to measure the effect of visual contrast on the flight speed of Drosophila melanogaster.

At low contrasts, speed is more variable and faster on average than at high contrasts.

Thus, the system is already a useful tool to study the neurobiology and behavior of freely flying animals.

If combined with other techniques, such as `virtual reality’-type computer graphics or genetic manipulation, the tracking system would offer a powerful new way to investigate the biology of flying animals.

Today I read a paper titled “Code Similarity on High Level Programs”

The abstract is:
This paper presents a new approach for code similarity on High Level programs.

Our technique is based on Fast Dynamic Time Warping, that builds a warp path or points relation with local restrictions.

The source code is represented into Time Series using the operators inside programming languages that makes possible the comparison.

This makes possible subsequence detection that represent similar code instructions.

In contrast with other code similarity algorithms, we do not make features extraction.

The experiments show that two source codes are similar when their respective Time Series are similar.

Today I read a paper titled “A New Clustering Algorithm Based Upon Flocking On Complex Network”

The abstract is:
We have proposed a model based upon flocking on a complex network, and then developed two clustering algorithms on the basis of it.

In the algorithms, firstly a \textit{k}-nearest neighbor (knn) graph as a weighted and directed graph is produced among all data points in a dataset each of which is regarded as an agent who can move in space, and then a time-varying complex network is created by adding long-range links for each data point.

Furthermore, each data point is not only acted by its \textit{k} nearest neighbors but also \textit{r} long-range neighbors through fields established in space by them together, so it will take a step along the direction of the vector sum of all fields.

It is more important that these long-range links provides some hidden information for each data point when it moves and at the same time accelerate its speed converging to a center.

As they move in space according to the proposed model, data points that belong to the same class are located at a same position gradually, whereas those that belong to different classes are away from one another.

Consequently, the experimental results have demonstrated that data points in datasets are clustered reasonably and efficiently, and the rates of convergence of clustering algorithms are fast enough.

Moreover, the comparison with other algorithms also provides an indication of the effectiveness of the proposed approach.

Today I read a paper titled “On the Efficiency of Strategies for Subdividing Polynomial Triangular Surface Patches”

The abstract is:
In this paper, we investigate the efficiency of various strategies for subdividing polynomial triangular surface patches.

We give a simple algorithm performing a regular subdivision in four calls to the standard de Casteljau algorithm (in its subdivision version).

A naive version uses twelve calls.

We also show that any method for obtaining a regular subdivision using the standard de Casteljau algorithm requires at least 4 calls.

Thus, our method is optimal.

We give another subdivision algorithm using only three calls to the de Casteljau algorithm.

Instead of being regular, the subdivision pattern is diamond-like.

Finally, we present a “spider-like” subdivision scheme producing six subtriangles in four calls to the de Casteljau algorithm.

Today I read a paper titled “Jamming in complex networks with degree correlation”

The abstract is:
We study the effects of the degree-degree correlations on the pressure congestion J when we apply a dynamical process on scale free complex networks using the gradient network approach.

We find that the pressure congestion for disassortative (assortative) networks is lower (bigger) than the one for uncorrelated networks which allow us to affirm that disassortative networks enhance transport through them.

This result agree with the fact that many real world transportation networks naturally evolve to this kind of correlation.

We explain our results showing that for the disassortative case the clusters in the gradient network turn out to be as much elongated as possible, reducing the pressure congestion J and observing the opposite behavior for the assortative case.

Finally we apply our model to real world networks, and the results agree with our theoretical model.

Today I read a paper titled “Predicting relevant empty spots in social interaction”

The abstract is:
An empty spot refers to an empty hard-to-fill space which can be found in the records of the social interaction, and is the clue to the persons in the underlying social network who do not appear in the records.

This contribution addresses a problem to predict relevant empty spots in social interaction.

Homogeneous and inhomogeneous networks are studied as a model underlying the social interaction.

A heuristic predictor function approach is presented as a new method to address the problem.

Simulation experiment is demonstrated over a homogeneous network.

A test data in the form of baskets is generated from the simulated communication.

Precision to predict the empty spots is calculated to demonstrate the performance of the presented approach.

Today I read a paper titled “Fundamentals of Mathematical Theory of Emotional Robots”

The abstract is:
In this book we introduce a mathematically formalized concept of emotion, robot’s education and other psychological parameters of intelligent robots.

We also introduce unitless coefficients characterizing an emotional memory of a robot.

Besides, the effect of a robot’s memory upon its emotional behavior is studied, and theorems defining fellowship and conflicts in groups of robots are proved.

Also unitless parameters describing emotional states of those groups are introduced, and a rule of making alternative (binary) decisions based on emotional selection is given.

We introduce a concept of equivalent educational process for robots and a concept of efficiency coefficient of an educational process, and suggest an algorithm of emotional contacts within a group of robots.

And generally, we present and describe a model of a virtual reality with emotional robots.

The book is meant for mathematical modeling specialists and emotional robot software developers.

Today I read a paper titled “The “Unfriending” Problem: The Consequences of Homophily in Friendship Retention for Causal Estimates of Social Influence”

The abstract is:
An increasing number of scholars are using longitudinal social network data to try to obtain estimates of peer or social influence effects.

These data may provide additional statistical leverage, but they can introduce new inferential problems.

In particular, while the confounding effects of homophily in friendship formation are widely appreciated, homophily in friendship retention may also confound causal estimates of social influence in longitudinal network data.

We provide evidence for this claim in a Monte Carlo analysis of the statistical model used by Christakis, Fowler, and their colleagues in numerous articles estimating “contagion” effects in social networks.

Our results indicate that homophily in friendship retention induces significant upward bias and decreased coverage levels in the Christakis and Fowler model if there is non-negligible friendship attrition over time.

Today I read a paper titled “Personal applications, based on moveable / resizable elements”

The abstract is:
All the modern day applications have the interface, absolutely defined by the developers.

The use of adaptive interface or dynamic layout allows some variations, but even all of them are predetermined on the design stage, because the best reaction (from designer’s view) on any possible users’ movement was hardcoded.

But there is a different world of applications, totally constructed on moveable / resizable elements; such applications turn the full control to the users.

The crucial thing in such programs is that not something but everything must become moveable and resizable.

This article describes the features of such applications and the algorithm behind their design.

Today I read a paper titled “Mining Meaning from Wikipedia”

The abstract is:
Wikipedia is a goldmine of information; not just for its many readers, but also for the growing community of researchers who recognize it as a resource of exceptional scale and utility.

It represents a vast investment of manual effort and judgment: a huge, constantly evolving tapestry of concepts and relations that is being applied to a host of tasks.

This article provides a comprehensive description of this work.

It focuses on research that extracts and makes use of the concepts, relations, facts and descriptions found in Wikipedia, and organizes the work into four broad categories: applying Wikipedia to natural language processing; using it to facilitate information retrieval and information extraction; and as a resource for ontology building.

The article addresses how Wikipedia is being used as is, how it is being improved and adapted, and how it is being combined with other structures to create entirely new resources.

We identify the research groups and individuals involved, and how their work has developed in the last few years.

We provide a comprehensive list of the open-source software they have produced.

Today I read a paper titled “Neural networks in 3D medical scan visualization”

The abstract is:
For medical volume visualization, one of the most important tasks is to reveal clinically relevant details from the 3D scan (CT, MRI …), e.g.

the coronary arteries, without obscuring them with less significant parts.

These volume datasets contain different materials which are difficult to extract and visualize with 1D transfer functions based solely on the attenuation coefficient.

Multi-dimensional transfer functions allow a much more precise classification of data which makes it easier to separate different surfaces from each other.

Unfortunately, setting up multi-dimensional transfer functions can become a fairly complex task, generally accomplished by trial and error.

This paper explains neural networks, and then presents an efficient way to speed up visualization process by semi-automatic transfer function generation.

We describe how to use neural networks to detect distinctive features shown in the 2D histogram of the volume data and how to use this information for data classification.

Today I read a paper titled “Being Rational or Aggressive? A Revisit to Dunbar’s Number in Online Social Networks”

The abstract is:
Recent years have witnessed the explosion of online social networks (OSNs).

They provide powerful IT-innovations for online social activities such as organizing contacts, publishing contents, and sharing interests between friends who may never meet before.

As more and more people become the active users of online social networks, one may ponder questions such as: (1) Do OSNs indeed improve our sociability? (2) To what extent can we expand our offline social spectrum in OSNs? (3) Can we identify some interesting user behaviors in OSNs? Our work in this paper just aims to answer these interesting questions.

To this end, we pay a revisit to the well-known Dunbar’s number in online social networks.

Our main research contributions are as follows.

First, to our best knowledge, our work is the first one that systematically validates the existence of the online Dunbar’s number in the range of [200,300].

To reach this, we combine using local-structure analysis and user-interaction analysis for extensive real-world OSNs.

Second, we divide OSNs users into two categories: rational and aggressive, and find that rational users intend to develop close and reciprocated relationships, whereas aggressive users have no consistent behaviors.

Third, we build a simple model to capture the constraints of time and cognition that affect the evolution of online social networks.

Finally, we show the potential use of our findings in viral marketing and privacy management in online social networks.

Today I read a paper titled “Detecting the Most Unusual Part of a Digital Image”

The abstract is:
The purpose of this paper is to introduce an algorithm that can detect the most unusual part of a digital image.

The most unusual part of a given shape is defined as a part of the image that has the maximal distance to all non intersecting shapes with the same form.

The method can be used to scan image databases with no clear model of the interesting part or large image databases, as for example medical databases.

Today I read a paper titled “Intrusion Detection Using Cost-Sensitive Classification”

The abstract is:
Intrusion Detection is an invaluable part of computer networks defense.

An important consideration is the fact that raising false alarms carries a significantly lower cost than not detecting at- tacks.

For this reason, we examine how cost-sensitive classification methods can be used in Intrusion Detection systems.

The performance of the approach is evaluated under different experimental conditions, cost matrices and different classification models, in terms of expected cost, as well as detection and false alarm rates.

We find that even under unfavourable conditions, cost-sensitive classification can improve performance significantly, if only slightly.

Today I read a paper titled “Thermodynamics of Information Retrieval”

The abstract is:
In this work, we suggest a parameterized statistical model (the gamma distribution) for the frequency of word occurrences in long strings of English text and use this model to build a corresponding thermodynamic picture by constructing the partition function.

We then use our partition function to compute thermodynamic quantities such as the free energy and the specific heat.

In this approach, the parameters of the word frequency model vary from word to word so that each word has a different corresponding thermodynamics and we suggest that differences in the specific heat reflect differences in how the words are used in language, differentiating keywords from common and function words.

Finally, we apply our thermodynamic picture to the problem of retrieval of texts based on keywords and suggest some advantages over traditional information retrieval methods.

Today I read a paper titled “The Accelerating Growth of Online Tagging Systems”

The abstract is:
Research on the growth of online tagging systems not only is interesting in its own right, but also yields insights for website management and semantic web analysis.

Traditional models that describing the growth of online systems can be divided between linear and nonlinear versions.

Linear models, including the BA model (Brabasi and Albert, 1999), assume that the average activity of users is a constant independent of population.

Hence the total activity is a linear function of population.

On the contrary, nonlinear models suggest that the average activity is affected by the size of the population and the total activity is a nonlinear function of population.

In the current study, supporting evidences for the nonlinear growth assumption are obtained from data on Internet users’ tagging behavior.

A power law relationship between the number of new tags (F) and the population (P), which can be expressed as F ~ P ^ gamma (gamma > 1), is found.

I call this pattern accelerating growth and find it relates the to time-invariant heterogeneity in individual activities.

I also show how a greater heterogeneity leads to a faster growth.

Today I read a paper titled “Interactive Hatching and Stippling by Example”

The abstract is:
We describe a system that lets a designer interactively draw patterns of strokes in the picture plane, then guide the synthesis of similar patterns over new picture regions.

Synthesis is based on an initial user-assisted analysis phase in which the system recognizes distinct types of strokes (hatching and stippling) and organizes them according to perceptual grouping criteria.

The synthesized strokes are produced by combining properties (eg.

length, orientation, parallelism, proximity) of the stroke groups extracted from the input examples.

We illustrate our technique with a drawing application that allows the control of attributes and scale-dependent reproduction of the synthesized patterns.

Today I read a paper titled “Assessing Cognitive Load on Web Search Tasks”

The abstract is:
Assessing cognitive load on web search is useful for characterizing search system features and search tasks with respect to their demands on the searcher’s mental effort.

It is also helpful for examining how individual differences among searchers (e.g.

cognitive abilities) affect the search process.

We examined cognitive load from the perspective of primary and secondary task performance.

A controlled web search study was conducted with 48 participants.

The primary task performance components were found to be significantly related to both the objective and the subjective task difficulty.

However, the relationship between objective and subjective task difficulty and the secondary task performance measures was weaker than expected.

The results indicate that the dual-task approach needs to be used with caution.

Today I read a paper titled “Simulating Spiking Neural P systems without delays using GPUs”

The abstract is:
We present in this paper our work regarding simulating a type of P system known as a spiking neural P system (SNP system) using graphics processing units (GPUs).

GPUs, because of their architectural optimization for parallel computations, are well-suited for highly parallelizable problems.

Due to the advent of general purpose GPU computing in recent years, GPUs are not limited to graphics and video processing alone, but include computationally intensive scientific and mathematical applications as well.

Moreover P systems, including SNP systems, are inherently and maximally parallel computing models whose inspirations are taken from the functioning and dynamics of a living cell.

In particular, SNP systems try to give a modest but formal representation of a special type of cell known as the neuron and their interactions with one another.

The nature of SNP systems allowed their representation as matrices, which is a crucial step in simulating them on highly parallel devices such as GPUs.

The highly parallel nature of SNP systems necessitate the use of hardware intended for parallel computations.

The simulation algorithms, design considerations, and implementation are presented.

Finally, simulation results, observations, and analyses using an SNP system that generates all numbers in $\mathbb N$ – {1} are discussed, as well as recommendations for future work.

Today I read a paper titled “Analytic treatment of the network synchronization problem with time delays”

The abstract is:
Motivated by novel results in the theory of network synchronization, we analyze the effects of nonzero time delays in stochastic synchronization problems with linear couplings in an arbitrary network.

We determine {\it analytically} the fundamental limit of synchronization efficiency in a noisy environment with uniform time delays.

We show that the optimal efficiency of the network is achieved for $\lambda\tau={{\pi^{3/2}}\over{2\sqrt{\pi}+4}}\approx0.738$, where $\lambda$ is the coupling strength (relaxation coefficient) and $\tau$ is the characteristic time delay in the communication between pairs of nodes.

Our analysis reveals the underlying mechanism responsible for the trade-off phenomena observed in recent numerical simulations of network synchronization problems.

Today I read a paper titled “Subjective Collaborative Filtering”

The abstract is:
We present an item-based approach for collaborative filtering.

We determine a list of recommended items for a user by considering their previous purchases.

Additionally other features of the users could be considered such as page views, search queries, etc…

In particular we address the problem of efficiently comparing items.

Our algorithm can efficiently approximate an estimate of the similarity between two items.

As measure of similarity we use an approximation of the Jaccard similarity that can be computed by constant time operations and one bitwise OR.

Moreover we improve the accuracy of the similarity by introducing the concept of user preference for a given product, which both takes into account multiple purchases and purchases of related items.

The product of the user preference and the Jaccard measure (or its approximation) is used as a score for deciding whether a given product has to be recommended.

Today I read a paper titled “Digital Restoration of Ancient Papyri”

The abstract is:
Image processing can be used for digital restoration of ancient papyri, that is, for a restoration performed on their digital images.

The digital manipulation allows reducing the background signals and enhancing the readability of texts.

In the case of very old and damaged documents, this is fundamental for identification of the patterns of letters.

Some examples of restoration, obtained with an image processing which uses edges detection and Fourier filtering, are shown.

One of them concerns 7Q5 fragment of the Dead Sea Scrolls.

Today I read a paper titled “Extensive Games with Possibly Unaware Players”

The abstract is:
Standard game theory assumes that the structure of the game is common knowledge among players.

We relax this assumption by considering extensive games where agents may be unaware of the complete structure of the game.

In particular, they may not be aware of moves that they and other agents can make.

We show how such games can be represented; the key idea is to describe the game from the point of view of every agent at every node of the game tree.

We provide a generalization of Nash equilibrium and show that every game with awareness has a generalized Nash equilibrium.

Finally, we extend these results to games with awareness of unawareness, where a player i may be aware that a player j can make moves that i is not aware of, and to subjective games, where payers may have no common knowledge regarding the actual game and their beliefs are incompatible with a common prior.

Today I read a paper titled “A 8 bits Pipeline Analog to Digital Converter Design for High Speed Camera Application”

The abstract is:
– This paper describes a pipeline analog-to-digital converter is implemented for high speed camera.

In the pipeline ADC design, prime factor is designing operational amplifier with high gain so ADC have been high speed.

The other advantage of pipeline is simple on concept, easy to implement in layout and have flexibility to increase speed.

We made design and simulation using Mentor Graphics Software with 0.6 \mu m CMOS technology with a total power dissipation of 75.47 mW.

Circuit techniques used include a precise comparator, operational amplifier and clock management.

A switched capacitor is used to sample and multiplying at each stage.

Simulation a worst case DNL and INL of 0.75 LSB.

The design operates at 5 V dc.

The ADC achieves a SNDR of 44.86 dB.

keywords: pipeline, switched capacitor, clock management .

Today I read a paper titled “Self-Assembly with Geometric Tiles”

The abstract is:
In this work we propose a generalization of Winfree’s abstract Tile Assembly Model (aTAM) in which tile types are assigned rigid shapes, or geometries, along each tile face.

We examine the number of distinct tile types needed to assemble shapes within this model, the temperature required for efficient assembly, and the problem of designing compact geometric faces to meet given compatibility specifications.

Our results show a dramatic decrease in the number of tile types needed to assemble $n \times n$ squares to $\Theta(\sqrt{\log n})$ at temperature 1 for the most simple model which meets a lower bound from Kolmogorov complexity, and $O(\log\log n)$ in a model in which tile aggregates must move together through obstacle free paths within the plane.

This stands in contrast to the $\Theta(\log n / \log\log n)$ tile types at temperature 2 needed in the basic aTAM.

We also provide a general method for simulating a large and computationally universal class of temperature 2 aTAM systems with geometric tiles at temperature 1.

Finally, we consider the problem of computing a set of compact geometric faces for a tile system to implement a given set of compatibility specifications.

We show a number of bounds on the complexity of geometry size needed for various classes of compatibility specifications, many of which we directly apply to our tile assembly results to achieve non-trivial reductions in geometry size.

Today I read a paper titled “How happy is your web browsing? A model to quantify satisfaction of an Internet user, searching for desired information”

The abstract is:
We feel happy when web-browsing operations provide us with necessary information; otherwise, we feel bitter.

How to measure this happiness (or bitterness)? How does the profile of happiness grow and decay during the course of web-browsing? We propose a probabilistic framework that models evolution of user satisfaction, on top of his/her continuous frustration at not finding the required information.

It is found that the cumulative satisfaction profile of a web-searching individual can be modeled effectively as the sum of random number of random terms, where each term is mutually independent random variable, originating from ‘memoryless’ Poisson flow.

Evolution of satisfaction over the entire time interval of user’s browsing was modeled with auto-correlation analysis.

A utilitarian marker, magnitude of greater than unity of which describe happy web-searching operations; and an empirical limit that connects user’s satisfaction with his frustration level – are proposed too.

Presence of pertinent information in the very first page of a web-site and magnitude of the decay parameter of user satisfaction (frustration, irritation etc.), are found to be two key aspects that dominate web-browser’s psychology.

The proposed model employed different combination of decay parameter, searching time and number of helpful web-sites.

Obtained results are found to match the results from three real-life case-studies.

Today I read a paper titled “The Digital Restoration of Da Vinci’s Sketches”

The abstract is:
A sketch, found in one of Leonardo da Vinci’s notebooks and covered by the written notes of this genius, has been recently restored.

The restoration reveals a possible self-portrait of the artist, drawn when he was young.

Here, we discuss the discovery of this self-portrait and the procedure used for restoration.

Actually, this is a restoration performed on the digital image of the sketch, a procedure that can easily extended and applied to ancient documents for studies of art and palaeography.

Today I read a paper titled “On the effect of the path length and transitivity of small-world networks on epidemic dynamics”

The abstract is:
We show how one can trace in a systematic way the coarse-grained solutions of individual-based stochastic epidemic models evolving on heterogeneous complex networks with respect to their topological characteristics.

In particular, we have developed algorithms that allow the tuning of the transitivity (clustering coefficient) and the average mean-path length allowing the investigation of the “pure” impacts of the two characteristics on the emergent behavior of detailed epidemic models.

The framework could be used to shed more light into the influence of weak and strong social ties on epidemic spread within small-world network structures, and ultimately to provide novel systematic computational modeling and exploration of better contagion control strategies.

Today I read a paper titled “On Endogenous Reconfiguration in Mobile Robotic Networks”

The abstract is:
In this paper, our focus is on certain applications for mobile robotic networks, where reconfiguration is driven by factors intrinsic to the network rather than changes in the external environment.

In particular, we study a version of the coverage problem useful for surveillance applications, where the objective is to position the robots in order to minimize the average distance from a random point in a given environment to the closest robot.

This problem has been well-studied for omni-directional robots and it is shown that optimal configuration for the network is a centroidal Voronoi configuration and that the coverage cost belongs to $\Theta(m^{-1/2})$, where $m$ is the number of robots in the network.

In this paper, we study this problem for more realistic models of robots, namely the double integrator (DI) model and the differential drive (DD) model.

We observe that the introduction of these motion constraints in the algorithm design problem gives rise to an interesting behavior.

For a \emph{sparser} network, the optimal algorithm for these models of robots mimics that for omni-directional robots.

We propose novel algorithms whose performances are within a constant factor of the optimal asymptotically (i.e., as $m \to +\infty$).

In particular, we prove that the coverage cost for the DI and DD models of robots is of order $m^{-1/3}$.

Additionally, we show that, as the network grows, these novel algorithms outperform the conventional algorithm; hence necessitating a reconfiguration in the network in order to maintain optimal quality of service.

Today I read a paper titled “An Image-Based Sensor System for Autonomous Rendez-Vous with Uncooperative Satellites”

The abstract is:
In this paper are described the image processing algorithms developed by SENER, Ingenieria y Sistemas to cope with the problem of image-based, autonomous rendez-vous (RV) with an orbiting satellite.

The methods developed have a direct application in the OLEV (Orbital Life Extension Extension Vehicle) mission.

OLEV is a commercial mission under development by a consortium formed by Swedish Space Corporation, Kayser-Threde and SENER, aimed to extend the operational life of geostationary telecommunication satellites by supplying them control, navigation and guidance services.

OLEV is planned to use a set of cameras to determine the angular position and distance to the client satellite during the complete phases of rendez-vous and docking, thus enabling the operation with satellites not equipped with any specific navigational aid to provide support during the approach.

The ability to operate with un-equipped client satellites significantly expands the range of applicability of the system under development, compared to other competing video technologies already tested in previous spatial missions, such as the ones described here below.

Today I read a paper titled “Geographic constraints on social network groups”

The abstract is:
Social groups are fundamental building blocks of human societies.

While our social interactions have always been constrained by geography, it has been impossible, due to practical difficulties, to evaluate the nature of this restriction on social group structure.

We construct a social network of individuals whose most frequent geographical locations are also known.

We also classify the individuals into groups according to a community detection algorithm.

We study the variation of geographical span for social groups of varying sizes, and explore the relationship between topological positions and geographic positions of their members.

We find that small social groups are geographically very tight, but become much more clumped when the group size exceeds about 30 members.

Also, we find no correlation between the topological positions and geographic positions of individuals within network communities.

These results suggest that spreading processes face distinct structural and spatial constraints.

Today I read a paper titled “Computing Good Nash Equilibria in Graphical Games”

The abstract is:
This paper addresses the problem of fair equilibrium selection in graphical games.

Our approach is based on the data structure called the {\em best response policy}, which was proposed by Kearns et al.

\cite{kls} as a way to represent all Nash equilibria of a graphical game.

In \cite{egg}, it was shown that the best response policy has polynomial size as long as the underlying graph is a path.

In this paper, we show that if the underlying graph is a bounded-degree tree and the best response policy has polynomial size then there is an efficient algorithm which constructs a Nash equilibrium that guarantees certain payoffs to all participants.

Another attractive solution concept is a Nash equilibrium that maximizes the social welfare.

We show that, while exactly computing the latter is infeasible (we prove that solving this problem may involve algebraic numbers of an arbitrarily high degree), there exists an FPTAS for finding such an equilibrium as long as the best response policy has polynomial size.

These two algorithms can be combined to produce Nash equilibria that satisfy various fairness criteria.

Today I read a paper titled “Across Browsers SVG Implementation”

The abstract is:
In this work SVG will be translated into VML or HTML by using Javascript based on Backbase Client Framework.

The target of this project is to implement SVG to be viewed in Internet Explorer without any plug-in and work together with other Backbase Client Framework languages.

The result of this project will be added as an extension to the current Backbase Client Framework.

Today I read a paper titled “Free and Open-Source Software is not an Emerging Property but Rather the Result of Studied Design”

The abstract is:
Free and open source software (FOSS) is considered by many, along with Wikipedia, the proof of an ongoing paradigm shift from hierarchically-managed and market-driven production of knowledge to heterarchical, collaborative and commons-based production styles.

In such perspective, it has become common place to refer to FOSS as a manifestation of collective intelligence where deliverables and artefacts emerge by virtue of mere cooperation, with no need for supervising leadership.

The paper argues that this assumption is based on limited understanding of the software development process, and may lead to wrong conclusions as to the potential of peer production.

The development of a less than trivial piece of software, irrespective of whether it be FOSS or proprietary, is a complex cooperative effort requiring the participation of many (often thousands of) individuals.

A subset of the participants always play the role of leading system and subsystem designers, determining architecture and functionality; the rest of the people work “underneath” them in a logical, functional sense.

While new and powerful forces, including FOSS, are clearly at work in the post-industrial, networked econ-omy, the currently ingenuous stage of research in the field of collective intelligence and networked cooperation must give way to a deeper level of consciousness, which requires an understanding of the software development process.

Today I read a paper titled “Trip Length Distribution Under Multiplicative Spatial Models of Supply and Demand: Theory and Sensitivity Analysis”

The abstract is:
We propose new probabilistic models for the spatial distribution of supply and demand and use the models to determine how the trip length distribution is affected by the relative shortage or excess of supply, the spatial clustering of supply and demand, and the degree of attraction or repulsion between supply and demand at different spatial scales.

The models have a multiplicative structure and in certain cases possess scale invariance properties.

Using detailed population data in metropolitan US regions validates the demand model.

The trip length distribution, evaluated under destination choice models of the intervening opportunities type, has quasi-analytic form.We take advantage of this feature to study the sensitivity of the trip length distribution to parameters of the demand, supply and destination choice models.

We find that trip length is affected in important but different ways by the spatial density of potential destinations, the dependence among their attractiveness levels, and the correlation between supply and demand at different spatial scales.

Today I read a paper titled “GPU-Based Interactive Visualization of Billion Point Cosmological Simulations”

The abstract is:
Despite the recent advances in graphics hardware capabilities, a brute force approach is incapable of interactively displaying terabytes of data.

We have implemented a system that uses hierarchical level-of-detailing for the results of cosmological simulations, in order to display visually accurate results without loading in the full dataset (containing over 10 billion points).

The guiding principle of the program is that the user should not be able to distinguish what they are seeing from a full rendering of the original data.

Furthermore, by using a tree-based system for levels of detail, the size of the underlying data is limited only by the capacity of the IO system containing it.

Today I read a paper titled “Ray-Based Reflectance Model for Diffraction”

The abstract is:
We present a novel method of simulating wave effects in graphics using ray–based renderers with a new function: the Wave BSDF (Bidirectional Scattering Distribution Function).

Reflections from neighboring surface patches represented by local BSDFs are mutually independent.

However, in many surfaces with wavelength-scale microstructures, interference and diffraction requires a joint analysis of reflected wavefronts from neighboring patches.

We demonstrate a simple method to compute the BSDF for the entire microstructure, which can be used independently for each patch.

This allows us to use traditional ray–based rendering pipelines to synthesize wave effects of light and sound.

We exploit the Wigner Distribution Function (WDF) to create transmissive, reflective, and emissive BSDFs for various diffraction phenomena in a physically accurate way.

In contrast to previous methods for computing interference, we circumvent the need to explicitly keep track of the phase of the wave by using BSDFs that include positive as well as negative coefficients.

We describe and compare the theory in relation to well understood concepts in rendering and demonstrate a straightforward implementation.

In conjunction with standard raytracers, such as PBRT, we demonstrate wave effects for a range of scenarios such as multi–bounce diffraction materials, holograms and reflection of high frequency surfaces.

Today I read a paper titled “Analyzing the Facebook Friendship Graph”

The abstract is:
Online Social Networks (OSN) during last years acquired a huge and increasing popularity as one of the most important emerging Web phenomena, deeply modifying the behavior of users and contributing to build a solid substrate of connections and relationships among people using the Web.

In this preliminary work paper, our purpose is to analyze Facebook, considering a significant sample of data reflecting relationships among subscribed users.

Our goal is to extract, from this platform, relevant information about the distribution of these relations and exploit tools and algorithms provided by the Social Network Analysis (SNA) to discover and, possibly, understand underlying similarities between the developing of OSN and real-life social networks.

Today I read a paper titled “Balancing transparency, efficiency and security in pervasive systems”

The abstract is:
This chapter will survey pervasive computing with a look at how its constraint for transparency affects issues of resource management and security.

The goal of pervasive computing is to render computing transparent, such that computing resources are ubiquitously offered to the user and services are proactively performed for a user without his or her intervention.

The task of integrating computing infrastructure into everyday life without making it excessively invasive brings about tradeoffs between flexibility and robustness, efficiency and effectiveness, as well as autonomy and reliability.

As the feasibility of ubiquitous computing and its real potential for mass applications are still a matter of controversy, this chapter will look into the underlying issues of resource management and authentication to discover how these can be handled in a least invasive fashion.

The discussion will be closed by an overview of the solutions proposed by current pervasive computing efforts, both in the area of generic platforms and for dedicated applications such as pervasive education and healthcare.

Today I read a paper titled “Distribution of Cognitive Load in Web Search”

The abstract is:
The search task and the system both affect the demand on cognitive resources during information search.

In some situations, the demands may become too high for a person.

This article has a three-fold goal.

First, it presents and critiques methods to measure cognitive load.

Second, it explores the distribution of load across search task stages.

Finally, it seeks to improve our understanding of factors affecting cognitive load levels in information search.

To this end, a controlled Web search experiment with forty-eight participants was conducted.

Interaction logs were used to segment search tasks semi-automatically into task stages.

Cognitive load was assessed using a new variant of the dual-task method.

Average cognitive load was found to vary by search task stages.

It was significantly higher during query formulation and user description of a relevant document as compared to examining search results and viewing individual documents.

Semantic information shown next to the search results lists in one of the studied interfaces was found to decrease mental demands during query formulation and examination of the search results list.

These findings demonstrate that changes in dynamic cognitive load can be detected within search tasks.

Dynamic assessment of cognitive load is of core interest to information science because it enriches our understanding of cognitive demands imposed on people engaged in the search process by a task and the interactive information retrieval system employed.

Today I read a paper titled “Seats at the table: the network of the editorial boards in information and library science”

The abstract is:
The structural properties of the network generated by the editorial activities of the members of the boards of “Information Science & Library Science” journals are explored through network analysis techniques.

The crossed presence of scholars on editorial boards, the phenomenon called interlocking editorship, is considered a proxy of the similarity of editorial policies.

The evidences support the idea that this group of journals is better described as a set of only relatively connected subfields.

In particular two main subfield are identified, consisting of research oriented journals devoted respectively to LIS and MIS.

The links between these two subsets are weak.

Around these two subsets there are a lot of (relatively) isolated professional journals or journals characterized more by their subject-matter content than by their focus on information flows.

It is possible to suggest that this configuration of the network may be the consequence of the youthfulness of Information Science & Library Science, which has not permitted yet to reach a general consensus through scholars on research aims, methods and instruments.

Today I read a paper titled “Impact of link deletions on public cooperation in scale-free networks”

The abstract is:
Working together in groups may be beneficial if compared to isolated efforts.

Yet this is true only if all group members contribute to the success.

If not, group efforts may act detrimentally on the fitness of their members.

Here we study the evolution of cooperation in public goods games on scale-free networks that are subject to deletion of links that are connected to the highest-degree individuals, i.e., on networks that are under attack.

We focus on the case where all groups a player belongs to are considered for the determination of payoffs; the so-called multi-group public goods games.

We find that the effect of link deletions on the evolution of cooperation is predominantly detrimental, although there exist regions of the multiplication factor where the existence of an “optimal” number of removed links for deterioration of cooperation can also be demonstrated.

The findings are explained by means of wealth distributions and analytical approximations, confirming that socially diverse states are crucial for the successful evolution of cooperation.

Today I read a paper titled “Fast Wavelet-Based Visual Classification”

The abstract is:
We investigate a biologically motivated approach to fast visual classification, directly inspired by the recent work of Serre et al.

Specifically, trading-off biological accuracy for computational efficiency, we explore using wavelet and grouplet-like transforms to parallel the tuning of visual cortex V1 and V2 cells, alternated with max operations to achieve scale and translation invariance.

A feature selection procedure is applied during learning to accelerate recognition.

We introduce a simple attention-like feedback mechanism, significantly improving recognition and robustness in multiple-object scenes.

In experiments, the proposed algorithm achieves or exceeds state-of-the-art success rate on object recognition, texture and satellite image classification, language identification and sound classification.

Today I read a paper titled “The Role of Time in the Creation of Knowledge”

The abstract is:
This paper I assume that in humans the creation of knowledge depends on a discrete time, or stage, sequential decision-making process subjected to a stochastic, information transmitting environment.

For each time-stage, this environment randomly transmits Shannon type information-packets to the decision-maker, who examines each of them for relevancy and then determines his optimal choices.

Using this set of relevant information-packets, the decision-maker adapts, over time, to the stochastic nature of his environment, and optimizes the subjective expected rate-of-growth of knowledge.

The decision-maker’s optimal actions, lead to a decision function that involves, over time, his view of the subjective entropy of the environmental process and other important parameters at each time-stage of the process.

Using this model of human behavior, one could create psychometric experiments using computer simulation and real decision-makers, to play programmed games to measure the resulting human performance.

Today I read a paper titled “Anisotropic selection in cellular genetic algorithms”

The abstract is:
In this paper we introduce a new selection scheme in cellular genetic algorithms (cGAs).

Anisotropic Selection (AS) promotes diversity and allows accurate control of the selective pressure.

First we compare this new scheme with the classical rectangular grid shapes solution according to the selective pressure: we can obtain the same takeover time with the two techniques although the spreading of the best individual is different.

We then give experimental results that show to what extent AS promotes the emergence of niches that support low coupling and high cohesion.

Finally, using a cGA with anisotropic selection on a Quadratic Assignment Problem we show the existence of an anisotropic optimal value for which the best average performance is observed.

Further work will focus on the selective pressure self-adjustment ability provided by this new selection scheme.