The science papers I've read

Today I read a paper titled “Optimal Sensor Configurations for Rectangular Target Dectection”

The abstract is:
Optimal search strategies where targets are observed at several different angles are found.

Targets are assumed to exhibit rectangular symmetry and have a uniformly-distributed orientation.

By rectangular symmetry, it is meant that one side of a target is the mirror image of its opposite side.

Finding an optimal solution is generally a hard problem.

Fortunately, symmetry principles allow analytical and intuitive solutions to be found.

One such optimal search strategy consists of choosing n angles evenly separated on the half-circle and leads to a lower bound of the probability of not detecting targets.

As no prior knowledge of the target orientation is required, such search strategies are also robust, a desirable feature in search and detection missions.

Today I read a paper titled “The Information Theory of Emotions of Musical Chords”

The abstract is:
The paper offers a solution to the centuries-old puzzle – why the major chords are perceived as happy and the minor chords as sad – based on the information theory of emotions.

A theory and a formula of musical emotions were created.

They define the sign and the amplitude of the utilitarian emotional coloration of separate major and minor chords through relative pitches of constituent sounds.

Keywords: chord, major, minor, the formula of musical emotions, the information theory of emotions.

Today I read a paper titled “Size matters: performance declines if your pixels are too big or too small”

The abstract is:
We present a conceptual model that describes the effect of pixel size on target acquisition.

We demonstrate the use of our conceptual model by applying it to predict and explain the results of an experiment to evaluate users’ performance in a target acquisition task involving three distinct display sizes: standard desktop, small and large displays.

The results indicate that users are fastest on standard desktop displays, undershoots are the most common error on small displays and overshoots are the most common error on large displays.

We propose heuristics to maintain usability when changing displays.

Finally, we contribute to the growing body of evidence that amplitude does affect performance in a display-based pointing task.

Today I read a paper titled “SimDialog: A visual game dialog editor”

The abstract is:
SimDialog is a visual editor for dialog in computer games.

This paper presents the design of SimDialog, illustrating how script writers and non-programmers can easily create dialog for video games with complex branching structures and dynamic response characteristics.

The system creates dialog as a directed graph.

This allows for play using the dialog with a state-based cause and effect system that controls selection of non-player character responses and can provide a basic scoring mechanism for games.

Today I read a paper titled “Persistent Robotic Tasks: Monitoring and Sweeping in Changing Environments”

The abstract is:
We present controllers that enable mobile robots to persistently monitor or sweep a changing environment.

The changing environment is modeled as a field which grows in locations that are not within range of a robot, and decreases in locations that are within range of a robot.

We assume that the robots travel on given closed paths.

The speed of each robot along its path is controlled to prevent the field from growing unbounded at any location.

We consider the space of speed controllers that can be parametrized by a finite set of basis functions.

For a single robot, we develop a linear program that is guaranteed to compute a speed controller in this space to keep the field bounded, if such a controller exists.

Another linear program is then derived whose solution is the speed controller that minimizes the maximum field value over the environment.

We extend our linear program formulation to develop a multi-robot controller that keeps the field bounded.

The multi-robot controller has the unique feature that it does not require communication among the robots.

Simulation studies demonstrate the robustness of the controllers to modeling errors, and to stochasticity in the environment.

Today I read a paper titled “Narrative Bridging – a specification of a modelling method for game design”

The abstract is:
Very little has been explored about the narrative as a process when constructing entertainment for interactive media.

Simultaneously, the interest in narrative vehicles increases while certain occupations, seeing the narrative as a structure, obscure the examination of the process of selecting, arranging and rendering story material.

To correct this deficiency, a method for a narrative bridging that encourages research and design while exploring narration as a process, is proposed with the aim to not diminish the properties of the interactive media.

This method focuses on the initial phase where establishing and handling the information takes place and creates a foundation that precedes its systematization and computation.

The aim is to give designers a comfortable design tool that firmly aids the design without interfering with creativity, and at the same time aids the construction of interplay between narration, spatiality and interactivity.

The method aided the practise of a discipline that was established through a qualitative study conducted as part of a university course in rapid prototyping.

The results demonstrated that the method aided time-constrained design processes, simultaneously detecting inconsistencies that would prevent the team from making improvements.

The method gave the team a shared vocabulary and outlook, allowing them to progress without interfering with the creative flow.

This enabled the team to reason about the process and easily advice design stakeholders.

The study also provides directions for future developments within research of narrative processes in game design.

Today I read a paper titled “Affective Ludology, Flow and Immersion in a First- Person Shooter: Measurement of Player Experience”

The abstract is:
Gameplay research about experiential phenomena is a challenging undertaking, given the variety of experiences that gamers encounter when playing and which currently do not have a formal taxonomy, such as flow, immersion, boredom, and fun.

These informal terms require a scientific explanation.

Ludologists also acknowledge the need to understand cognition, emotion, and goal- oriented behavior of players from a psychological perspective by establishing rigorous methodologies.

This paper builds upon and extends prior work in an area for which we would like to coin the term “affective ludology.” The area is concerned with the affective measurement of player-game interaction.

The experimental study reported here investigated different traits of gameplay experience using subjective (i.e., questionnaires) and objective (i.e., psychophysiological) measures.

Participants played three Half-Life 2 game level design modifications while measures such as electromyography (EMG), electrodermal activity (EDA) were taken and questionnaire responses were collected.

A level designed for combat-oriented flow experience demonstrated significant high-arousal positive affect emotions.

This method shows that emotional patterns emerge from different level designs, which has great potential for providing real-time emotional profiles of gameplay that may be generated together with self- reported subjective player experience descriptions.

Today I read a paper titled “Quarantine generated phase transition in epidemic spreading”

The abstract is:
We study the critical effect of quarantine on the propagation of epidemics on an adaptive network of social contacts.

For this purpose, we analyze the susceptible-infected-recovered (SIR) model in the presence of quarantine, where susceptible individuals protect themselves by disconnecting their links to infected neighbors with probability w, and reconnecting them to other susceptible individuals chosen at random.

Starting from a single infected individual, we show by an analytical approach and simulations that there is a phase transition at a critical rewiring (quarantine) threshold w_c separating a phase (w= w_c) where the disease does not spread out.

We find that in our model the topology of the network strongly affects the size of the propagation, and that w_c increases with the mean degree and heterogeneity of the network.

We also find that w_c is reduced if we perform a preferential rewiring, in which the rewiring probability is proportional to the degree of infected nodes.

Today I read a paper titled “On-the-fly erasure coding for real-time video applications”

The abstract is:
This paper introduces a robust point-to-point transmission scheme: Tetrys, that relies on a novel on-the-fly erasure coding concept which reduces the delay for recovering lost data at the receiver side.

In current erasure coding schemes, the packets that are not rebuilt at the receiver side are either lost or delayed by at least one RTT before transmission to the application.

The present contribution aims at demonstrating that Tetrys coding scheme can fill the gap between real-time applications requirements and full reliability.

Indeed, we show that in several cases, Tetrys can recover lost packets below one RTT over lossy and best-effort networks.

We also show that Tetrys allows to enable full reliability without delay compromise and as a result: significantly improves the performance of time constrained applications.

For instance, our evaluations present that video-conferencing applications obtain a PSNR gain up to 7dB compared to classic block-based erasure codes.

Today I read a paper titled “Predictors of short-term decay of cell phone contacts in a large scale communication network”

The abstract is:
Under what conditions is an edge present in a social network at time t likely to decay or persist by some future time t + Delta(t)? Previous research addressing this issue suggests that the network range of the people involved in the edge, the extent to which the edge is embedded in a surrounding structure, and the age of the edge all play a role in edge decay.

This paper uses weighted data from a large-scale social network built from cell-phone calls in an 8-week period to determine the importance of edge weight for the decay/persistence process.

In particular, we study the relative predictive power of directed weight, embeddedness, newness, and range (measured as outdegree) with respect to edge decay and assess the effectiveness with which a simple decision tree and logistic regression classifier can accurately predict whether an edge that was active in one time period continues to be so in a future time period.

We find that directed edge weight, weighted reciprocity and time-dependent measures of edge longevity are highly predictive of whether we classify an edge as persistent or decayed, relative to the other types of factors at the dyad and neighborhood level.

Today I read a paper titled “The thermodynamics of human reaction times”

The abstract is:
I present a new approach for the interpretation of reaction time (RT) data from behavioral experiments.

From a physical perspective, the entropy of the RT distribution provides a model-free estimate of the amount of processing performed by the cognitive system.

In this way, the focus is shifted from the conventional interpretation of individual RTs being either long or short, into their distribution being more or less complex in terms of entropy.

The new approach enables the estimation of the cognitive processing load without reference to the informational content of the stimuli themselves, thus providing a more appropriate estimate of the cognitive impact of different sources of information that are carried by experimental stimuli or tasks.

The paper introduces the formulation of the theory, followed by an empirical validation using a database of human RTs in lexical tasks (visual lexical decision and word naming).

The results show that this new interpretation of RTs is more powerful than the traditional one.

The method provides theoretical estimates of the processing loads elicited by individual stimuli.

These loads sharply distinguish the responses from different tasks.

In addition, it provides upper-bound estimates for the speed at which the system processes information.

Finally, I argue that the theoretical proposal, and the associated empirical evidence, provide strong arguments for an adaptive system that systematically adjusts its operational processing speed to the particular demands of each stimulus.

This finding is in contradiction with Hick’s law, which posits a relatively constant processing speed within an experimental context.

Today I read a paper titled “Rumor Evolution in Social Networks”

The abstract is:
Social network is a main tunnel of rumor spreading.

Previous studies are concentrated on a static rumor spreading.

The content of the rumor is invariable during the whole spreading process.

Indeed, the rumor evolves constantly in its spreading process, which grows shorter, more concise, more easily grasped and told.

In an early psychological experiment, researchers found about 70% of details in a rumor were lost in the first 6 mouth-to-mouth transmissions \cite{TPR}.

Based on the facts, we investigate rumor spreading on social networks, where the content of the rumor is modified by the individuals with a certain probability.

In the scenario, they have two choices, to forward or to modify.

As a forwarder, an individual disseminates the rumor directly to its neighbors.

As a modifier, conversely, an individual revises the rumor before spreading it out.

When the rumor spreads on the social networks, for instance, scale-free networks and small-world networks, the majority of individuals actually are infected by the multi-revised version of the rumor, if the modifiers dominate the networks.

Our observation indicates that the original rumor may lose its influence in the spreading process.

Similarly, a true information may turn to be a rumor as well.

Our result suggests the rumor evolution should not be a negligible question, which may provide a better understanding of the generation and destruction of a rumor.

Today I read a paper titled “Time-Dependent 2-D Vector Field Topology: An Approach Inspired by Lagrangian Coherent Structures”

The abstract is:
This paper presents an approach to a time-dependent variant of the concept of vector field topology for 2-D vector fields.

Vector field topology is defined for steady vector fields and aims at discriminating the domain of a vector field into regions of qualitatively different behaviour.

The presented approach represents a generalization for saddle-type critical points and their separatrices to unsteady vector fields based on generalized streak lines, with the classical vector field topology as its special case for steady vector fields.

The concept is closely related to that of Lagrangian coherent structures obtained as ridges in the finite-time Lyapunov exponent field.

The proposed approach is evaluated on both 2-D time-dependent synthetic and vector fields from computational fluid dynamics.

Today I read a paper titled “Computer Model of a “Sense of Humour”. II. Realization in Neural Networks”

The abstract is:
The computer realization of a “sense of humour” requires the creation of an algorithm for solving the “linguistic problem”, i.e.

the problem of recognizing a continuous sequence of polysemantic images.

Such algorithm may be realized in the Hopfield model of a neural network after its proper modification.

Today I read a paper titled “3D Face Recognition with Sparse Spherical Representations”

The abstract is:
This paper addresses the problem of 3D face recognition using simultaneous sparse approximations on the sphere.

The 3D face point clouds are first aligned with a novel and fully automated registration process.

They are then represented as signals on the 2D sphere in order to preserve depth and geometry information.

Next, we implement a dimensionality reduction process with simultaneous sparse approximations and subspace projection.

It permits to represent each 3D face by only a few spherical functions that are able to capture the salient facial characteristics, and hence to preserve the discriminant facial information.

We eventually perform recognition by effective matching in the reduced space, where Linear Discriminant Analysis can be further activated for improved recognition performance.

The 3D face recognition algorithm is evaluated on the FRGC v.1.0 data set, where it is shown to outperform classical state-of-the-art solutions that work with depth images.

Today I read a paper titled “Learning Unification-Based Natural Language Grammars”

The abstract is:
When parsing unrestricted language, wide-covering grammars often undergenerate.

Undergeneration can be tackled either by sentence correction, or by grammar correction.

This thesis concentrates upon automatic grammar correction (or machine learning of grammar) as a solution to the problem of undergeneration.

Broadly speaking, grammar correction approaches can be classified as being either {\it data-driven}, or {\it model-based}.

Data-driven learners use data-intensive methods to acquire grammar.

They typically use grammar formalisms unsuited to the needs of practical text processing and cannot guarantee that the resulting grammar is adequate for subsequent semantic interpretation.

That is, data-driven learners acquire grammars that generate strings that humans would judge to be grammatically ill-formed (they {\it overgenerate}) and fail to assign linguistically plausible parses.

Model-based learners are knowledge-intensive and are reliant for success upon the completeness of a {\it model of grammaticality}.

But in practice, the model will be incomplete.

Given that in this thesis we deal with undergeneration by learning, we hypothesise that the combined use of data-driven and model-based learning would allow data-driven learning to compensate for model-based learning’s incompleteness, whilst model-based learning would compensate for data-driven learning’s unsoundness.

We describe a system that we have used to test the hypothesis empirically.

The system combines data-driven and model-based learning to acquire unification-based grammars that are more suitable for practical text parsing.

Using the Spoken English Corpus as data, and by quantitatively measuring undergeneration, overgeneration and parse plausibility, we show that this hypothesis is correct..

Today I read a paper titled “It’s Not What You Have, But How You Use It: Compromises in Mobile Device Use”

The abstract is:
As users begin to use many more devices for personal information management (PIM) than just the traditional desktop computer, it is essential for HCI researchers to understand how these devices are being used in the wild and their roles in users’ information environments.

We conducted a study of 220 knowledge workers about their devices, the activities they performed on each, and the groups of devices used together.

Our findings indicate that several devices are often used in groups; integrated multi-function portable devices have begun to replace single-function devices for communication (e.g.

email and IM).

Users use certain features opportunistically because they happen to be carrying a multi-function device with them.

The use of multiple devices and multi-function devices is fraught with compromises as users must choose and make trade-offs among various factors.

Today I read a paper titled “Gesture Recognition with a Focus on Important Actions by Using a Path Searching Method in Weighted Graph”

The abstract is:
This paper proposes a method of gesture recognition with a focus on important actions for distinguishing similar gestures.

The method generates a partial action sequence by using optical flow images, expresses the sequence in the eigenspace, and checks the feature vector sequence by applying an optimum path-searching method of weighted graph to focus the important actions.

Also presented are the results of an experiment on the recognition of similar sign language words.

Today I read a paper titled “A Framework for Designing 3D Virtual Environments”

The abstract is:
The process of design and development of virtual environments can be supported by tools and frameworks, to save time in technical aspects and focusing on the content.

In this paper we present an academic framework which provides several levels of abstraction to ease this work.

It includes state-of-the-art components we devised or integrated adopting open-source solutions in order to face specific problems.

Its architecture is modular and customizable, the code is open-source.

Today I read a paper titled “Singularity Analysis of Limited-dof Parallel Manipulators using Grassmann-Cayley Algebra”

The abstract is:
This paper characterizes geometrically the singularities of limited DOF parallel manipulators.

The geometric conditions associated with the dependency of six Pl\”ucker vector of lines (finite and infinite) constituting the rows of the inverse Jacobian matrix are formulated using Grassmann-Cayley algebra.

Manipulators under consideration do not need to have a passive spherical joint somewhere in each leg.

This study is illustrated with three example robots .

Today I read a paper titled “Robot Swarms in an Uncertain World: Controllable Adaptability”

The abstract is:
There is a belief that complexity and chaos are essential for adaptability.

But life deals with complexity every moment, without the chaos that engineers fear so, by invoking goal-directed behaviour.

Goals can be programmed.

That is why living organisms give us hope to achieve adaptability in robots.

In this paper a method for the description of a goal-directed, or programmed, behaviour, interacting with uncertainty of environment, is described.

We suggest reducing the structural (goals, intentions) and stochastic components (probability to realise the goal) of individual behaviour to random variables with nominal values to apply probabilistic approach.

This allowed us to use a Normalized Entropy Index to detect the system state by estimating the contribution of each agent to the group behaviour.

The number of possible group states is 27.

We argue that adaptation has a limited number of possible paths between these 27 states.

Paths and states can be programmed so that after adjustment to any particular case of task and conditions, adaptability will never involve chaos.

We suggest the application of the model to operation of robots or other devices in remote and/or dangerous places.

Today I read a paper titled “An Estimation of the Shortest and Largest Average Path Length in Graphs of Given Density”

The abstract is:
Many real world networks (graphs) are observed to be ‘small worlds’, i.e., the average path length among nodes is small.

On the other hand, it is somewhat unclear what other average path length values networks can produce.

In particular, it is not known what the maximum and the minimum average path length values are.

In this paper we provide a lower estimation for the shortest average path length (l) values in connected networks, and the largest possible average path length values in networks with given size and density.

To the latter end, we construct a special family of graphs and calculate their average path lengths.

We also demonstrate the correctness of our estimation by simulations.

Today I read a paper titled “Unstructured Human Activity Detection from RGBD Images”

The abstract is:
Being able to detect and recognize human activities is essential for several applications, including personal assistive robotics.

In this paper, we perform detection and recognition of unstructured human activity in unstructured environments.

We use a RGBD sensor (Microsoft Kinect) as the input sensor, and compute a set of features based on human pose and motion, as well as based on image and pointcloud information.

Our algorithm is based on a hierarchical maximum entropy Markov model (MEMM), which considers a person’s activity as composed of a set of sub-activities.

We infer the two-layered graph structure using a dynamic programming approach.

We test our algorithm on detecting and recognizing twelve different activities performed by four people in different environments, such as a kitchen, a living room, an office, etc., and achieve good performance even when the person was not seen before in the training set.

Today I read a paper titled “A Vortex Method for Bi-phasic Fluids Interacting with Rigid Bodies”

The abstract is:
We present an accurate Lagrangian method based on vortex particles, level-sets, and immersed boundary methods, for animating the interplay between two fluids and rigid solids.

We show that a vortex method is a good choice for simulating bi-phase flow, such as liquid and gas, with a good level of realism.

Vortex particles are localized at the interfaces between the two fluids and within the regions of high turbulence.

We gain local precision and efficiency from the stable advection permitted by the vorticity formulation.

Moreover, our numerical method straightforwardly solves the two-way coupling problem between the fluids and animated rigid solids.

This new approach is validated through numerical comparisons with reference experiments from the computational fluid community.

We also show that the visually appealing results obtained in the CG community can be reproduced with increased efficiency and an easier implementation.

Today I read a paper titled “Probabilistically Safe Vehicle Control in a Hostile Environment”

The abstract is:
In this paper we present an approach to control a vehicle in a hostile environment with static obstacles and moving adversaries.

The vehicle is required to satisfy a mission objective expressed as a temporal logic specification over a set of properties satisfied at regions of a partitioned environment.

We model the movements of adversaries in between regions of the environment as Poisson processes.

Furthermore, we assume that the time it takes for the vehicle to traverse in between two facets of each region is exponentially distributed, and we obtain the rate of this exponential distribution from a simulator of the environment.

We capture the motion of the vehicle and the vehicle updates of adversaries distributions as a Markov Decision Process.

Using tools in Probabilistic Computational Tree Logic, we find a control strategy for the vehicle that maximizes the probability of accomplishing the mission objective.

We demonstrate our approach with illustrative case studies.

Today I read a paper titled “A path following algorithm for the graph matching problem”

The abstract is:
We propose a convex-concave programming approach for the labeled weighted graph matching problem.

The convex-concave programming formulation is obtained by rewriting the weighted graph matching problem as a least-square problem on the set of permutation matrices and relaxing it to two different optimization problems: a quadratic convex and a quadratic concave optimization problem on the set of doubly stochastic matrices.

The concave relaxation has the same global minimum as the initial graph matching problem, but the search for its global minimum is also a hard combinatorial problem.

We therefore construct an approximation of the concave problem solution by following a solution path of a convex-concave problem obtained by linear interpolation of the convex and concave formulations, starting from the convex relaxation.

This method allows to easily integrate the information on graph label similarities into the optimization problem, and therefore to perform labeled weighted graph matching.

The algorithm is compared with some of the best performing graph matching methods on four datasets: simulated graphs, QAPLib, retina vessel images and handwritten chinese characters.

In all cases, the results are competitive with the state-of-the-art.

Today I read a paper titled “Established Clustering Procedures for Network Analysis”

The abstract is:
In light of the burgeoning interest in network analysis in the new millenium, we bring to the attention of contemporary network theorists, a two-stage double-standarization and hierarchical clustering (single-linkage-like) procedure devised in 1974.

In its many applications over the next decade–primarily to the migration flows between geographic subdivisions within nations–the presence was often revealed of “hubs”.

These are, typically, “cosmopolitan/non-provincial” areas–such as the French capital, Paris–which send and receive people relatively broadly across their respective nations.

Additionally, this two-stage procedure–which “might very well be the most successful application of cluster analysis” (R.

C.

Dubes)–has detected many (physically or socially) isolated groups (regions) of areas, such as those forming the southern islands, Shikoku and Kyushu, of Japan, the Italian islands of Sardinia and Sicily, and the New England region of the United States.

Further, we discuss a (complementary) approach developed in 1976, involving the application of the max-flow/min-cut theorem to raw/non-standardized flows.

Today I read a paper titled “Colorization of Natural Images via L1 Optimization”

The abstract is:
Natural images in the colour space YUV have been observed to have a non-Gaussian, heavy tailed distribution (called ‘sparse’) when the filter G(U)(r) = U(r) – sum_{s \in N(r)} w{(Y)_{rs}} U(s), is applied to the chromacity channel U (and equivalently to V), where w is a weighting function constructed from the intensity component Y [1].

In this paper we develop Bayesian analysis of the colorization problem using the filter response as a regularization term to arrive at a non-convex optimization problem.

This problem is convexified using L1 optimization which often gives the same results for sparse signals [2].

It is observed that L1 optimization, in many cases, over-performs the famous colorization algorithm by Levin et al [3].

Today I read a paper titled “Discrete Complex Structure on Surfel Surfaces”

The abstract is:
This paper defines a theory of conformal parametrization of digital surfaces made of surfels equipped with a normal vector.

The main idea is to locally project each surfel to the tangent plane, therefore deforming its aspect-ratio.

It is a generalization of the theory known for polyhedral surfaces.

The main difference is that the conformal ratios that appear are no longer real in general.

It yields a generalization of the standard Laplacian on weighted graphs.

Today I read a paper titled “Feature Dynamic Bayesian Networks”

The abstract is:
Feature Markov Decision Processes (PhiMDPs) are well-suited for learning agents in general environments.

Nevertheless, unstructured (Phi)MDPs are limited to relatively simple environments.

Structured MDPs like Dynamic Bayesian Networks (DBNs) are used for large-scale real-world problems.

In this article I extend PhiMDP to PhiDBN.

The primary contribution is to derive a cost criterion that allows to automatically extract the most relevant features from the environment, leading to the “best” DBN representation.

I discuss all building blocks required for a complete general learning algorithm.

Today I read a paper titled “Fairness in Combinatorial Auctioning Systems”

The abstract is:
One of the Multi-Agent Systems that is widely used by various government agencies, buyers and sellers in a market economy, in such a manner so as to attain optimized resource allocation, is the Combinatorial Auctioning System (CAS).

We study another important aspect of resource allocations in CAS, namely fairness.

We present two important notions of fairness in CAS, extended fairness and basic fairness.

We give an algorithm that works by incorporating a metric to ensure fairness in a CAS that uses the Vickrey-Clark-Groves (VCG) mechanism, and uses an algorithm of Sandholm to achieve optimality.

Mathematical formulations are given to represent measures of extended fairness and basic fairness.

Today I read a paper titled “Increasing Linear Dynamic Range of Commercial Digital Photocamera Used in Imaging Systems with Optical Coding”

The abstract is:
Methods of increasing linear optical dynamic range of commercial photocamera for optical-digital imaging systems are described.

Use of such methods allows to use commercial photocameras for optical measurements.

Experimental results are reported.

Today I read a paper titled “Controlling wheelchairs by body motions: A learning framework for the adaptive remapping of space”

The abstract is:
Learning to operate a vehicle is generally accomplished by forming a new cognitive map between the body motions and extrapersonal space.

Here, we consider the challenge of remapping movement-to-space representations in survivors of spinal cord injury, for the control of powered wheelchairs.

Our goal is to facilitate this remapping by developing interfaces between residual body motions and navigational commands that exploit the degrees of freedom that disabled individuals are most capable to coordinate.

We present a new framework for allowing spinal cord injured persons to control powered wheelchairs through signals derived from their residual mobility.

The main novelty of this approach lies in substituting the more common joystick controllers of powered wheelchairs with a sensor shirt.

This allows the whole upper body of the user to operate as an adaptive joystick.

Considerations about learning and risks have lead us to develop a safe testing environment in 3D Virtual Reality.

A Personal Augmented Reality Immersive System (PARIS) allows us to analyse learning skills and provide users with an adequate training to control a simulated wheelchair through the signals generated by body motions in a safe environment.

We provide a description of the basic theory, of the development phases and of the operation of the complete system.

We also present preliminary results illustrating the processing of the data and supporting of the feasibility of this approach.

Today I read a paper titled “Spatial Networks”

The abstract is:
Complex systems are very often organized under the form of networks where nodes and edges are embedded in space.

Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, neural networks, are all examples where space is relevant and where topology alone does not contain all the information.

Characterizing and understanding the structure and the evolution of spatial networks is thus crucial for many different fields ranging from urbanism to epidemiology.

An important consequence of space on networks is that there is a cost associated to the length of edges which in turn has dramatic effects on the topological structure of these networks.

We will expose thoroughly the current state of our understanding of how the spatial constraints affect the structure and properties of these networks.

We will review the most recent empirical observations and the most important models of spatial networks.

We will also discuss various processes which take place on these spatial networks, such as phase transitions, random walks, synchronization, navigation, resilience, and disease spread.

Today I read a paper titled “Elementary epistemological features of machine intelligence”

The abstract is:
Theoretical analysis of machine intelligence (MI) is useful for defining a common platform in both theoretical and applied artificial intelligence (AI).

The goal of this paper is to set canonical definitions that can assist pragmatic research in both strong and weak AI.

Described epistemological features of machine intelligence include relationship between intelligent behavior, intelligent and unintelligent machine characteristics, observable and unobservable entities and classification of intelligence.

The paper also establishes algebraic definitions of efficiency and accuracy of MI tests as their quality measure.

The last part of the paper addresses the learning process with respect to the traditional epistemology and the epistemology of MI described here.

The proposed views on MI positively correlate to the Hegelian monistic epistemology and contribute towards amalgamating idealistic deliberations with the AI theory, particularly in a local frame of reference.

Today I read a paper titled “Opinion formation and cyclic dominance in adaptive networks”

The abstract is:
The Rock-Paper-Scissors(RPS) game is a paradigmatic model for cyclic dominance in biological systems.

Here we consider this game in the social context of competition between opinions in a networked society.

In our model, every agent has an opinion which is drawn from the three choices: rock, paper or scissors.

In every timestep a link is selected randomly and the game is played between the nodes connected by the link.

The loser either adopts the opinion of the winner or rewires the link.

These rules define an adaptive network on which the agent’s opinions coevolve with the network topology of social contacts.

We show analytically and numerically that nonequilibrium phase transitions occur as a function of the rewiring strength.

The transitions separate four distinct phases which differ in the observed dynamics of opinions and topology.

In particular, there is one phase where the population settles to an arbitrary consensus opinion.

We present a detailed analysis of the corresponding transitions revealing an apparently paradoxial behavior.

The system approaches consensus states where they are unstable, whereas other dynamics prevail when the consensus states are stable.

Today I read a paper titled “Quantum Interaction Approach in Cognition, Artificial Intelligence and Robotics”

The abstract is:
The mathematical formalism of quantum mechanics has been successfully employed in the last years to model situations in which the use of classical structures gives rise to problematical situations, and where typically quantum effects, such as ‘contextuality’ and ‘entanglement’, have been recognized.

This ‘Quantum Interaction Approach’ is briefly reviewed in this paper focusing, in particular, on the quantum models that have been elaborated to describe how concepts combine in cognitive science, and on the ensuing identification of a quantum structure in human thought.

We point out that these results provide interesting insights toward the development of a unified theory for meaning and knowledge formalization and representation.

Then, we analyze the technological aspects and implications of our approach, and a particular attention is devoted to the connections with symbolic artificial intelligence, quantum computation and robotics.

Today I read a paper titled “Using explosive percolation in analysis of real-world networks”

The abstract is:
We apply a variant of the explosive percolation procedure to large real-world networks, and show with finite-size scaling that the university class, ordinary or explosive, of the resulting percolation transition depends on the structural properties of the network as well as the number of unoccupied links considered for comparison in our procedure.

We observe that in our social networks, the percolation clusters close to the critical point are related to the community structure.

This relationship is further highlighted by applying the procedure to model networks with pre-defined communities.

Today I read a paper titled “Dimensionality Reduction and Reconstruction using Mirroring Neural Networks and Object Recognition based on Reduced Dimension Characteristic Vector”

The abstract is:
In this paper, we present a Mirroring Neural Network architecture to perform non-linear dimensionality reduction and Object Recognition using a reduced lowdimensional characteristic vector.

In addition to dimensionality reduction, the network also reconstructs (mirrors) the original high-dimensional input vector from the reduced low-dimensional data.

The Mirroring Neural Network architecture has more number of processing elements (adalines) in the outer layers and the least number of elements in the central layer to form a converging-diverging shape in its configuration.

Since this network is able to reconstruct the original image from the output of the innermost layer (which contains all the information about the input pattern), these outputs can be used as object signature to classify patterns.

The network is trained to minimize the discrepancy between actual output and the input by back propagating the mean squared error from the output layer to the input layer.

After successfully training the network, it can reduce the dimension of input vectors and mirror the patterns fed to it.

The Mirroring Neural Network architecture gave very good results on various test patterns.

Today I read a paper titled “L2-optimal image interpolation and its applications to medical imaging”

The abstract is:
Digital medical images are always displayed scaled to fit particular view.

Interpolation is responsible for this scaling, and if not done properly, can significantly degrade diagnostic image quality.

However, theoretically-optimal interpolation algorithms may also be the most time-consuming and impractical.

We propose a new approach, adapted to the needs of digital medical imaging, to combine high interpolation speed and superior L2-optimal image quality.

Today I read a paper titled “Music By Numbers”

The abstract is:
In this paper we present a mathematical way of defining musical modes, we derive a formula for the total number of modes and define the musicality of a mode as the total number of harmonic chords whithin the mode.

We also give an algorithm for the construction of a duet of melodic lines given a sequence of numbers and a mode.

We attach the .mus files of the counterpoints obtained by using the sequence of primes and several musical modes.

Today I read a paper titled “Doubly Robust Policy Evaluation and Learning”

The abstract is:
We study decision making in environments where the reward is only partially observed, but can be modeled as a function of an action and an observed context.

This setting, known as contextual bandits, encompasses a wide variety of applications including health-care policy and Internet advertising.

A central task is evaluation of a new policy given historic data consisting of contexts, actions and received rewards.

The key challenge is that the past data typically does not faithfully represent proportions of actions taken by a new policy.

Previous approaches rely either on models of rewards or models of the past policy.

The former are plagued by a large bias whereas the latter have a large variance.

In this work, we leverage the strength and overcome the weaknesses of the two approaches by applying the doubly robust technique to the problems of policy evaluation and optimization.

We prove that this approach yields accurate value estimates when we have either a good (but not necessarily consistent) model of rewards or a good (but not necessarily consistent) model of past policy.

Extensive empirical comparison demonstrates that the doubly robust approach uniformly improves over existing techniques, achieving both lower variance in value estimation and better policies.

As such, we expect the doubly robust approach to become common practice.

Today I read a paper titled “Topological Quantum Error Correction with Optimal Encoding Rate”

The abstract is:
We prove the existence of topological quantum error correcting codes with encoding rates $k/n$ asymptotically approaching the maximum possible value.

Explicit constructions of these topological codes are presented using surfaces of arbitrary genus.

We find a class of regular toric codes that are optimal.

For physical implementations, we present planar topological codes.

Today I read a paper titled “Improving Human-Computer Interaction by Developing Culture-sensitive Applications based on Common Sense Knowledge”

The abstract is:
The advent of Web 3.0, claiming for personalization in interactive systems (Lassila & Hendler, 2007), and the need for systems capable of interacting in a more natural way in the future society flooded with computer systems and devices (Harper et al., 2008) show that great advances in HCI should be done.

This chapter presents some contributions of LIA for the future of HCI, defending that using common sense knowledge is a possibility for improving HCI, especially because people assign meaning to their messages based on their common sense and, therefore, the use of this knowledge in developing user interfaces can make them more intuitive to the end-user.

Moreover, as common sense knowledge varies from group to group of people, it can be used for developing applications capable of giving different feedback for different target groups, as the applications presented along this chapter illustrate, allowing, in this way, interface personalization taking into account cultural issues.

For the purpose of using common sense knowledge in the development and design of computer systems, it is necessary to provide an architecture that allows it.

This chapter presents LIAs approaches for common sense knowledge acquisition, representation and use, as well as for natural language processing, contributing with those ones who intent to get into this challenging world to get started.

Today I read a paper titled “User Experience, Software Interfaces, and The Unconscious”

The abstract is:
Ideas about how to increase the unconscious participation in interaction between ‘a human’ and ‘a computer’ are developed in this paper.

Evidence of impact of the unconscious functioning is presented.

The unconscious is characterised as being a responsive, contextual, and autonomous participant of human-computer interaction.

The unconscious participation occurs independently of one’s cognitive and educational levels and, if ignored, leads to learning inefficiencies and compulsive behaviours, illustrations of which are provided.

Three practical approaches to a study of subjective user experience are outlined as follows: (a) tracing operant conditioning effects of software, (b) registering signs of brain activity psychological or information processing meaning of which is well-explored and (c) exploring submodality interfaces.

Implications for improvement of current usability study methods, such as eye-tracking, are generally considered.

Conclusions consider advantages and disadvantages of unconscious-embracing design and remind about a loss of human evolutionary choices if unconscious participation is ignored, complicated or blocked in interaction with computer interfaces and built environment.

Today I read a paper titled “Simulated annealing for weighted polygon packing”

The abstract is:
In this paper we present a new algorithm for a layout optimization problem: this concerns the placement of weighted polygons inside a circular container, the two objectives being to minimize imbalance of mass and to minimize the radius of the container.

This problem carries real practical significance in industrial applications (such as the design of satellites), as well as being of significant theoretical interest.

Previous work has dealt with circular or rectangular objects, but here we deal with the more realistic case where objects may be represented as polygons and the polygons are allowed to rotate.

We present a solution based on simulated annealing and first test it on instances with known optima.

Our results show that the algorithm obtains container radii that are close to optimal.

We also compare our method with existing algorithms for the (special) rectangular case.

Experimental results show that our approach out-performs these methods in terms of solution quality.

Today I read a paper titled “Cybermatter”

The abstract is:
In this paper we examine several aspects of the impact of Cyberworld onto our Reality conceptions, and their social implications.

Today I read a paper titled “Clique Graphs and Overlapping Communities”

The abstract is:
It is shown how to construct a clique graph in which properties of cliques of a fixed order in a given graph are represented by vertices in a weighted graph.

Various definitions and motivations for these weights are given.

The detection of communities or clusters is used to illustrate how a clique graph may be exploited.

In particular a benchmark network is shown where clique graphs find the overlapping communities accurately while vertex partition methods fail.

Today I read a paper titled “Self-organization in social tagging systems”

The abstract is:
Individuals often imitate each other to fall into the typical group, leading to a self-organized state of typical behaviors in a community.

In this paper, we model self-organization in social tagging systems and illustrate the underlying interaction and dynamics.

Specifically, we introduce a model in which individuals adjust their own tagging tendency to imitate the average tagging tendency.

We found that when users are of low confidence, they tend to imitate others and lead to a self-organized state with active tagging.

On the other hand, when users are of high confidence and are stubborn for changes, tagging becomes inactive.

We observe a phase transition at a critical level of user confidence when the system changes from one regime to the other.

The distributions of post length obtained from the model are compared to real data which show good agreements.

Today I read a paper titled “Navigation in non-uniform density social networks”

The abstract is:
Recent empirical investigations suggest a universal scaling law for the spatial structure of social networks.

It is found that the probability density distribution of an individual to have a friend at distance $d$ scales as $P(d)\propto d^{-1}$.

Since population density is non-uniform in real social networks, a scale invariant friendship network(SIFN) based on the above empirical law is introduced to capture this phenomenon.

We prove the time complexity of navigation in 2-dimensional SIFN is at most $O(\log^4 n)$.

In the real searching experiment, individuals often resort to extra information besides geography location.

Thus, real-world searching process may be seen as a projection of navigation in a $k$-dimensional SIFN($k>2$).

Therefore, we also discuss the relationship between high and low dimensional SIFN.

Particularly, we prove a 2-dimensional SIFN is the projection of a 3-dimensional SIFN.

As a matter of fact, this result can also be generated to any $k$-dimensional SIFN.