Archives for 2013

Today I read a paper titled “Automatic Recommendation for Online Users Using Web Usage Mining”

The abstract is:
A real world challenging task of the web master of an organization is to match the needs of user and keep their attention in their web site.

So, only option is to capture the intuition of the user and provide them with the recommendation list.

Most specifically, an online navigation behavior grows with each passing day, thus extracting information intelligently from it is a difficult issue.

Web master should use web usage mining method to capture intuition.

A WUM is designed to operate on web server logs which contain user’s navigation.

Hence, recommendation system using WUM can be used to forecast the navigation pattern of user and recommend those to user in a form of recommendation list.

In this paper, we propose a two tier architecture for capturing users intuition in the form of recommendation list containing pages visited by user and pages visited by other user’s having similar usage profile.

The practical implementation of proposed architecture and algorithm shows that accuracy of user intuition capturing is improved.

Today I read a paper titled “PageRank Optimization by Edge Selection”

The abstract is:
The importance of a node in a directed graph can be measured by its PageRank.

The PageRank of a node is used in a number of application contexts – including ranking websites – and can be interpreted as the average portion of time spent at the node by an infinite random walk.

We consider the problem of maximizing the PageRank of a node by selecting some of the edges from a set of edges that are under our control.

By applying results from Markov decision theory, we show that an optimal solution to this problem can be found in polynomial time.

Our core solution results in a linear programming formulation, but we also provide an alternative greedy algorithm, a variant of policy iteration, which runs in polynomial time, as well.

Finally, we show that, under the slight modification for which we are given mutually exclusive pairs of edges, the problem of PageRank optimization becomes NP-hard.

Today I read a paper titled “Moveable objects and applications, based on them”

The abstract is:
The inner views of all our applications are predetermined by the designers; only some non-significant variations are allowed with the help of adaptive interface.

In several programs you can find some moveable objects, but it is an extremely rare thing.

However, the design of applications on the basis of moveable and resizable objects opens an absolutely new way of programming; such applications are much more effective in users’ work, because each user can adjust an application to his purposes.

Programs, using adaptive interface, only implement the designer’s ideas of what would be the best reaction to any of the users’ doings or commands.

Applications on moveable elements do not have such predetermined system of rules; they are fully controlled by the users.

This article describes and demonstrates the new way of applications’ design.

Today I read a paper titled “Urologic robots and future directions”

The abstract is:
PURPOSE OF REVIEW: Robot-assisted laparoscopic surgery in urology has gained immense popularity with the daVinci system, but a lot of research teams are working on new robots.

The purpose of this study is to review current urologic robots and present future development directions.

RECENT FINDINGS: Future systems are expected to advance in two directions: improvements of remote manipulation robots and developments of image-guided robots.

SUMMARY: The final goal of robots is to allow safer and more homogeneous outcomes with less variability of surgeon performance, as well as new tools to perform tasks on the basis of medical transcutaneous imaging, in a less invasive way, at lower costs.

It is expected that improvements for a remote system could be augmented in reality, with haptic feedback, size reduction, and development of new tools for natural orifice translumenal endoscopic surgery.

The paradigm of image-guided robots is close to clinical availability and the most advanced robots are presented with end-user technical assessments.

It is also notable that the potential of robots lies much further ahead than the accomplishments of the daVinci system.

The integration of imaging with robotics holds a substantial promise, because this can accomplish tasks otherwise impossible.

Image-guided robots have the potential to offer a paradigm shift.

Today I read a paper titled “Deployment of mobile routers ensuring coverage and connectivity”

The abstract is:
Maintaining connectivity among a group of autonomous agents exploring an area is very important, as it promotes cooperation between the agents and also helps message exchanges which are very critical for their mission.

Creating an underlying Ad-hoc Mobile Router Network (AMRoNet) using simple robotic routers is an approach that facilitates communication between the agents without restricting their movements.

We address the following question in our paper: How to create an AMRoNet with local information and with minimum number of routers? We propose two new localized and distributed algorithms 1) agent-assisted router deployment and 2) a self-spreading for creating AMRoNet.

The algorithms use a greedy deployment strategy for deploying routers effectively into the area maximizing coverage and a triangular deployment strategy to connect different connected component of routers from different base stations.

Empirical analysis shows that the proposed algorithms are the two best localized approaches to create AMRoNets.

Today I read a paper titled “What Stops Social Epidemics?”

The abstract is:
Theoretical progress in understanding the dynamics of spreading processes on graphs suggests the existence of an epidemic threshold below which no epidemics form and above which epidemics spread to a significant fraction of the graph.

We have observed information cascades on the social media site Digg that spread fast enough for one initial spreader to infect hundreds of people, yet end up affecting only 0.1% of the entire network.

We find that two effects, previously studied in isolation, combine cooperatively to drastically limit the final size of cascades on Digg.

First, because of the highly clustered structure of the Digg network, most people who are aware of a story have been exposed to it via multiple friends.

This structure lowers the epidemic threshold while moderately slowing the overall growth of cascades.

In addition, we find that the mechanism for social contagion on Digg points to a fundamental difference between information spread and other contagion processes: despite multiple opportunities for infection within a social group, people are less likely to become spreaders of information with repeated exposure.

The consequences of this mechanism become more pronounced for more clustered graphs.

Ultimately, this effect severely curtails the size of social epidemics on Digg.

Today I read a paper titled “A distributed Approach for Access and Visibility Task with a Manikin and a Robot in a Virtual Reality Environment”

The abstract is:
This paper presents a new method, based on a multi-agent system and on a digital mock-up technology, to assess an efficient path planner for a manikin or a robot for access and visibility task taking into account ergonomic constraints or joint and mechanical limits.

In order to solve this problem, the human operator is integrated in the process optimization to contribute to a global perception of the environment.

This operator cooperates, in real-time, with several automatic local elementary agents.

The result of this work validates solutions through the digital mock-up; it can be applied to simulate maintenability and mountability tasks.

Today I read a paper titled “Characterizing the speed and paths of shared bicycles in Lyon”

The abstract is:
Thanks to numerical data gathered by Lyon’s shared bicycling system V\’elo’v, we are able to analyze 11.6 millions bicycle trips, leading to the first robust characterization of urban bikers’ behaviors.

We show that bicycles outstrip cars in downtown Lyon, by combining high speed and short paths.These data also allows us to calculate V\’elo’v fluxes on all streets, pointing to interesting locations for bike paths.

Today I read a paper titled “Evaluation of Three Vision Based Object Perception Methods for a Mobile Robot”

The abstract is:
This paper addresses object perception applied to mobile robotics.

Being able to perceive semantically meaningful objects in unstructured environments is a key capability in order to make robots suitable to perform high-level tasks in home environments.

However, finding a solution for this task is daunting: it requires the ability to handle the variability in image formation in a moving camera with tight time constraints.

The paper brings to attention some of the issues with applying three state of the art object recognition and detection methods in a mobile robotics scenario, and proposes methods to deal with windowing/segmentation.

Thus, this work aims at evaluating the state-of-the-art in object perception in an attempt to develop a lightweight solution for mobile robotics use/research in typical indoor settings.

Today I read a paper titled “Nonlinear Receding-Horizon Control of Rigid Link Robot Manipulators”

The abstract is:
The approximate nonlinear receding-horizon control law is used to treat the trajectory tracking control problem of rigid link robot manipulators.

The derived nonlinear predictive law uses a quadratic performance index of the predicted tracking error and the predicted control effort.

A key feature of this control law is that, for their implementation, there is no need to perform an online optimization, and asymptotic tracking of smooth reference trajectories is guaranteed.

It is shown that this controller achieves the positions tracking objectives via link position measurements.

The stability convergence of the output tracking error to the origin is proved.

To enhance the robustness of the closed loop system with respect to payload uncertainties and viscous friction, an integral action is introduced in the loop.

A nonlinear observer is used to estimate velocity.

Simulation results for a two-link rigid robot are performed to validate the performance of the proposed controller.

Keywords: receding-horizon control, nonlinear observer, robot manipulators, integral action, robustness.

Today I read a paper titled “Artificial Intelligence Techniques for Steam Generator Modelling”

The abstract is:
This paper investigates the use of different Artificial Intelligence methods to predict the values of several continuous variables from a Steam Generator.

The objective was to determine how the different artificial intelligence methods performed in making predictions on the given dataset.

The artificial intelligence methods evaluated were Neural Networks, Support Vector Machines, and Adaptive Neuro-Fuzzy Inference Systems.

The types of neural networks investigated were Multi-Layer Perceptions, and Radial Basis Function.

Bayesian and committee techniques were applied to these neural networks.

Each of the AI methods considered was simulated in Matlab.

The results of the simulations showed that all the AI methods were capable of predicting the Steam Generator data reasonably accurately.

However, the Adaptive Neuro-Fuzzy Inference system out performed the other methods in terms of accuracy and ease of implementation, while still achieving a fast execution time as well as a reasonable training time.

Today I read a paper titled “The Inverse Task of the Reflexive Game Theory: Theoretical Matters, Practical Applications and Relationship with Other Issues”

The abstract is:
The Reflexive Game Theory (RGT) has been recently proposed by Vladimir Lefebvre to model behavior of individuals in groups.

The goal of this study is to introduce the Inverse task.

We consider methods of solution together with practical applications.

We present a brief overview of the RGT for easy understanding of the problem.

We also develop the schematic representation of the RGT inference algorithms to create the basis for soft- and hardware solutions of the RGT tasks.

We propose a unified hierarchy of schemas to represent humans and robots.

This hierarchy is considered as a unified framework to solve the entire spectrum of the RGT tasks.

We conclude by illustrating how this framework can be applied for modeling of mixed groups of humans and robots.

All together this provides the exhaustive solution of the Inverse task and clearly illustrates its role and relationships with other issues considered in the RGT.

Today I read a paper titled “Lexical Knowledge Representation in an Intelligent Dictionary Help System”

The abstract is:
The frame-based knowledge representation model adopted in IDHS (Intelligent Dictionary Help System) is described in this paper.

It is used to represent the lexical knowledge acquired automatically from a conventional dictionary.

Moreover, the enrichment processes that have been performed on the Dictionary Knowledge Base and the dynamic exploitation of this knowledge – both based on the exploitation of the properties of lexical semantic relations – are also described..

Today I read a paper titled “An Eye Tracking Study into the Effects of Graph Layout”

The abstract is:
Graphs are typically visualized as node-link diagrams.

Although there is a fair amount of research focusing on crossing minimization to improve readability, little attention has been paid on how to handle crossings when they are an essential part of the final visualizations.

This requires us to understand how people read graphs and how crossings affect reading performance.

As an initial step to this end, a preliminary eye tracking experiment was conducted.

The specific purpose of this experiment was to test the effects of crossing angles and geometric-path tendency on eye movements and performance.

Sixteen subjects performed both path search and node locating tasks with six drawings.

The results showed that small angles can slow down and trigger extra eye movements, causing delays for path search tasks, whereas crossings have little impact on node locating tasks.

Geometric-path tendency indicates that a path between two nodes can become harder to follow when many branches of the path go toward the target node.

The insights obtained are discussed with a view to further confirmation in future work.