justin

Today I read a paper titled “A small-world of weak ties provides optimal global integration of self-similar modules in functional brain networks”

The abstract is:
The human brain is organized in functional modules.

Such an organization presents a basic conundrum: modules ought to be sufficiently independent to guarantee functional specialization and sufficiently connected to bind multiple processors for efficient information transfer.

It is commonly accepted that small-world architecture of short lengths and large local clustering may solve this problem.

However, there is intrinsic tension between shortcuts generating small-worlds and the persistence of modularity; a global property unrelated to local clustering.

Here, we present a possible solution to this puzzle.

We first show that a modified percolation theory can define a set of hierarchically organized modules made of strong links in functional brain networks.

These modules are “large-world” self-similar structures and, therefore, are far from being small-world.

However, incorporating weaker ties to the network converts it into a small-world preserving an underlying backbone of well-defined modules.

Remarkably, weak ties are precisely organized as predicted by theory maximizing information transfer with minimal wiring cost.

This trade-off architecture is reminiscent of the “strength of weak ties” crucial concept of social networks.

Such a design suggests a natural solution to the paradox of efficient information flow in the highly modular structure of the brain.

Today I read a paper titled “A Distributed Software Architecture for Collaborative Teleoperation based on a VR Platform and Web Application Interoperability”

The abstract is:
Augmented Reality and Virtual Reality can provide to a Human Operator (HO) a real help to complete complex tasks, such as robot teleoperation and cooperative teleassistance.

Using appropriate augmentations, the HO can interact faster, safer and easier with the remote real world.

In this paper, we present an extension of an existing distributed software and network architecture for collaborative teleoperation based on networked human-scaled mixed reality and mobile platform.

The first teleoperation system was composed by a VR application and a Web application.

However the 2 systems cannot be used together and it is impossible to control a distant robot simultaneously.

Our goal is to update the teleoperation system to permit a heterogeneous collaborative teleoperation between the 2 platforms.

An important feature of this interface is based on different Mobile platforms to control one or many robots.

Today I read a paper titled “Digital herders and phase transition in a voting model”

The abstract is:
In this paper, we discuss a voting model with two candidates, C_1 and C_2.

We set two types of voters–herders and independents.

The voting of independent voters is based on their fundamental values; on the other hand, the voting of herders is based on the number of votes.

Herders always select the majority of the previous $r$ votes, which is visible to them.

We call them digital herders.

We can accurately calculate the distribution of votes for special cases.

When r>=3, we find that a phase transition occurs at the upper limit of t, where t is the discrete time (or number of votes).

As the fraction of herders increases, the model features a phase transition beyond which a state where most voters make the correct choice coexists with one where most of them are wrong.

On the other hand, when r<3, there is no phase transition.

In this case, the herders’ performance is the same as that of the independent voters.

Finally, we recognize the behavior of human beings by conducting simple experiments.

Today I read a paper titled “Fast Color Quantization Using Weighted Sort-Means Clustering”

The abstract is:
Color quantization is an important operation with numerous applications in graphics and image processing.

Most quantization methods are essentially based on data clustering algorithms.

However, despite its popularity as a general purpose clustering algorithm, k-means has not received much respect in the color quantization literature because of its high computational requirements and sensitivity to initialization.

In this paper, a fast color quantization method based on k-means is presented.

The method involves several modifications to the conventional (batch) k-means algorithm including data reduction, sample weighting, and the use of triangle inequality to speed up the nearest neighbor search.

Experiments on a diverse set of images demonstrate that, with the proposed modifications, k-means becomes very competitive with state-of-the-art color quantization methods in terms of both effectiveness and efficiency.

Today I read a paper titled “GPU-based Image Analysis on Mobile Devices”

The abstract is:
With the rapid advances in mobile technology many mobile devices are capable of capturing high quality images and video with their embedded camera.

This paper investigates techniques for real-time processing of the resulting images, particularly on-device utilizing a graphical processing unit.

Issues and limitations of image processing on mobile devices are discussed, and the performance of graphical processing units on a range of devices measured through a programmable shader implementation of Canny edge detection.

Today I read a paper titled “Telerobotic Pointing Gestures Shape Human Spatial Cognition”

The abstract is:
This paper aimed to explore whether human beings can understand gestures produced by telepresence robots.

If it were the case, they can derive meaning conveyed in telerobotic gestures when processing spatial information.

We conducted two experiments over Skype in the present study.

Participants were presented with a robotic interface that had arms, which were teleoperated by an experimenter.

The robot could point to virtual locations that represented certain entities.

In Experiment 1, the experimenter described spatial locations of fictitious objects sequentially in two conditions: speech condition (SO, verbal descriptions clearly indicated the spatial layout) and speech and gesture condition (SR, verbal descriptions were ambiguous but accompanied by robotic pointing gestures).

Participants were then asked to recall the objects’ spatial locations.

We found that the number of spatial locations recalled in the SR condition was on par with that in the SO condition, suggesting that telerobotic pointing gestures compensated ambiguous speech during the process of spatial information.

In Experiment 2, the experimenter described spatial locations non-sequentially in the SR and SO conditions.

Surprisingly, the number of spatial locations recalled in the SR condition was even higher than that in the SO condition, suggesting that telerobotic pointing gestures were more powerful than speech in conveying spatial information when information was presented in an unpredictable order.

The findings provide evidence that human beings are able to comprehend telerobotic gestures, and importantly, integrate these gestures with co-occurring speech.

This work promotes engaging remote collaboration among humans through a robot intermediary.

Today I read a paper titled “Social Networks and Spin Glasses”

The abstract is:
The networks formed from the links between telephones observed in a month’s call detail records (CDRs) in the UK are analyzed, looking for the characteristics thought to identify a communications network or a social network.

Some novel methods are employed.

We find similarities to both types of network.

We conclude that, just as analogies to spin glasses have proved fruitful for optimization of large scale practical problems, there will be opportunities to exploit a statistical mechanics of the formation and dynamics of social networks in today’s electronically connected world.

Today I read a paper titled “Entropy-based Tuning of Musical Instruments”

The abstract is:
The human sense of hearing perceives a combination of sounds ‘in tune’ if the corresponding harmonic spectra are correlated, meaning that the neuronal excitation pattern in the inner ear exhibits some kind of order.

Based on this observation it is suggested that musical instruments such as pianos can be tuned by minimizing the Shannon entropy of suitably preprocessed Fourier spectra.

This method reproduces not only the correct stretch curve but also similar pitch fluctuations as in the case of high-quality aural tuning.

Today I read a paper titled “Multi-command Tactile and Auditory Brain Computer Interface based on Head Position Stimulation”

The abstract is:
We study the extent to which vibrotactile stimuli delivered to the head of a subject can serve as a platform for a brain computer interface (BCI) paradigm.

Six head positions are used to evoke combined somatosensory and auditory (via the bone conduction effect) brain responses, in order to define a multimodal tactile and auditory brain computer interface (taBCI).

Experimental results of subjects performing online taBCI, using stimuli with a moderately fast inter-stimulus interval (ISI), validate the taBCI paradigm, while the feasibility of the concept is illuminated through information transfer rate case studies.

Today I read a paper titled “Acoustic Communication for Medical Nanorobots”

The abstract is:
Communication among microscopic robots (nanorobots) can coordinate their activities for biomedical tasks.

The feasibility of in vivo ultrasonic communication is evaluated for micron-size robots broadcasting into various types of tissues.

Frequencies between 10MHz and 300MHz give the best tradeoff between efficient acoustic generation and attenuation for communication over distances of about 100 microns.

Based on these results, we find power available from ambient oxygen and glucose in the bloodstream can readily support communication rates of about 10,000 bits/second between micron-sized robots.

We discuss techniques, such as directional acoustic beams, that can increase this rate.

The acoustic pressure fields enabling this communication are unlikely to damage nearby tissue, and short bursts at considerably higher power could be of therapeutic use.

Today I read a paper titled “An Innovative Scheme For Effectual Fingerprint Data Compression Using Bezier Curve Representations”

The abstract is:
Naturally, with the mounting application of biometric systems, there arises a difficulty in storing and handling those acquired biometric data.

Fingerprint recognition has been recognized as one of the most mature and established technique among all the biometrics systems.

In recent times, with fingerprint recognition receiving increasingly more attention the amount of fingerprints collected has been constantly creating enormous problems in storage and transmission.

Henceforth, the compression of fingerprints has emerged as an indispensable step in automated fingerprint recognition systems.

Several researchers have presented approaches for fingerprint image compression.

In this paper, we propose a novel and efficient scheme for fingerprint image compression.

The presented scheme utilizes the Bezier curve representations for effective compression of fingerprint images.

Initially, the ridges present in the fingerprint image are extracted along with their coordinate values using the approach presented.

Subsequently, the control points are determined for all the ridges by visualizing each ridge as a Bezier curve.

The control points of all the ridges determined are stored and are used to represent the fingerprint image.

When needed, the fingerprint image is reconstructed from the stored control points using Bezier curves.

The quality of the reconstructed fingerprint is determined by a formal evaluation.

The proposed scheme achieves considerable memory reduction in storing the fingerprint.

Today I read a paper titled “Delays Induce an Exponential Memory Gap for Rendezvous in Trees”

The abstract is:
The aim of rendezvous in a graph is meeting of two mobile agents at some node of an unknown anonymous connected graph.

In this paper, we focus on rendezvous in trees, and, analogously to the efforts that have been made for solving the exploration problem with compact automata, we study the size of memory of mobile agents that permits to solve the rendezvous problem deterministically.

We assume that the agents are identical, and move in synchronous rounds.

We first show that if the delay between the starting times of the agents is arbitrary, then the lower bound on memory required for rendezvous is Omega(log n) bits, even for the line of length n.

This lower bound meets a previously known upper bound of O(log n) bits for rendezvous in arbitrary graphs of size at most n.

Our main result is a proof that the amount of memory needed for rendezvous with simultaneous start depends essentially on the number L of leaves of the tree, and is exponentially less impacted by the number n of nodes.

Indeed, we present two identical agents with O(log L + loglog n) bits of memory that solve the rendezvous problem in all trees with at most n nodes and at most L leaves.

Hence, for the class of trees with polylogarithmically many leaves, there is an exponential gap in minimum memory size needed for rendezvous between the scenario with arbitrary delay and the scenario with delay zero.

Moreover, we show that our upper bound is optimal by proving that Omega(log L + loglog n)$ bits of memory are required for rendezvous, even in the class of trees with degrees bounded by 3.