Archives for 2014

Today I read a paper titled “The effects of computer assisted and distance learning of geometric modelling”

The abstract is:
The effects of computer-assisted and distance learning of geometric modeling and computer aided geometric design are studied

It was shown that computer algebra systems and dynamic geometric environments can be considered as excellent tools for teaching mathematical concepts of mentioned areas, and distance education technologies would be indispensable for consolidation of successfully passed topics

Today I read a paper titled “Parsimonious Flooding in Geometric Random-Walks”

The abstract is:
We study the information spreading yielded by the Parsimonious-Flooding Protocol in geometric Mobile Ad-Hoc Networks

We consider $n$ agents on a convex plane region of diameter $D$ performing independent random walks with move radius $\rho$

At any time step, every active agent $v$ informs every non-informed agent which is within distance $R$ from $v$ ($R>0$ is the transmission radius)

An agent is only active at the time step immediately after the one in which has been informed and, after that, she is removed

At the initial time step, a source agent is informed and we look at the completion time of the protocol, i.e., the first time step (if any) in which all agents are informed

This random process is equivalent to the well-known Susceptible-Infective-Removed (SIR) infection process in Mathematical Epidemiology

No analytical results are available for this random process over any explicit mobility model

The presence of removed agents makes this process much more complex than the (standard) flooding

We prove optimal bounds on the completion time depending on the parameters $n$, $D$, $R$, and $\rho$

The obtained bounds hold with high probability

We remark that our method of analysis provides a clear picture of the dynamic shape of the information spreading (or infection wave) over the time

Today I read a paper titled “Writer Identification Using Inexpensive Signal Processing Techniques”

The abstract is:
We propose to use novel and classical audio and text signal-processing and otherwise techniques for “inexpensive” fast writer identification tasks of scanned hand-written documents “visually”

The “inexpensive” refers to the efficiency of the identification process in terms of CPU cycles while preserving decent accuracy for preliminary identification

This is a comparative study of multiple algorithm combinations in a pattern recognition pipeline implemented in Java around an open-source Modular Audio Recognition Framework (MARF) that can do a lot more beyond audio

We present our preliminary experimental findings in such an identification task

We simulate “visual” identification by “looking” at the hand-written document as a whole rather than trying to extract fine-grained features out of it prior classification

Today I read a paper titled “Experimental evidence for mixed reality states”

The abstract is:
Recently researchers at the University of Illinois coupled a real pendulum to its virtual counterpart

They observed that the two pendulums suddenly start to move in synchrony if their lengths are sufficiently close

In this synchronized state, the boundary between the real system and the virtual system is blurred, that is, the pendulums are in a mixed reality state

An instantaneous, bidirectional coupling is a prerequisite for mixed reality states

In this article we explore the implications of mixed reality states in the context of controlling real-world systems

Today I read a paper titled “Dynamic Simulation of Soft Heterogeneous Objects”

The abstract is:
This paper describes a 2D and 3D simulation engine that quantitatively models the statics, dynamics, and non-linear deformation of heterogeneous soft bodies in a computationally efficient manner

There is a large body of work simulating compliant mechanisms

These normally assume small deformations with homogeneous material properties actuated with external forces

There is also a large body of research on physically-based deformable objects for applications in computer graphics with the purpose of generating realistic appearances at the expense of accuracy

Here we present a simulation framework in which an object may be composed of any number of interspersed materials with varying properties (stiffness, density, etc.) to enable true heterogeneous multi-material simulation

Collisions are handled to prevent self-penetration due to large deformation, which also allows multiple bodies to interact

A volumetric actuation method is implemented to impart motion to the structures which opens the door to the design of novel structures and mechanisms

The simulator was implemented efficiently such that objects with thousands of degrees of freedom can be simulated at suitable framerates for user interaction using a single thread of a typical desktop computer

The code is written in platform agnostic C++ and is fully open source

This research opens the door to the dynamic simulation of freeform 3D multi-material mechanisms and objects in a manner suitable for design automation

Today I read a paper titled “WoodTouch, a new interaction interface for wooden furniture”

The abstract is:
If wood has been with us since time immemorial, being part of our environment, housing and tools, now wood has gain momentum, as it is clear that wood improves our life style

Because of the healthiness, resistance, ecology and comfort, wood is important for all of us, no matter what our life style is

WOODTOUCH Project aims to open a completely new market for furniture and interior design companies, enabling touch interaction between the user and wooden furniture surfaces

Why not switch on or dim the lights touching a wooden table? Why not turn on the heating system? Why not use wood as a touch sensitive surface for domotic control? The furniture designed with this novel technology, offers a wooden outer image and has different touch sensitive areas over the ones the user is able to control all sorts of electric appliances touching over a wooden surface

Today I read a paper titled “Perceptual analyses of action-related impact sounds”

The abstract is:
Among environmental sounds, we have chosen to study a class of action-related impact sounds: automobile door closure sounds

We propose to describe these sounds using a model composed of perceptual properties

The development of the perceptual model was derived from the evaluation of many door closure sounds measured under controlled laboratory listening conditions

However, listening to such sounds normally occurs within a natural context, which probably modifies their perception

We therefore need to study differences between the real situation and the laboratory situation by following standard practices in order to specify the precise listening conditions and observe the influence of previous learning, expectations, action-perception interactions, and attention given to sounds

Our process consists in doing in situ experiments that are compared with specific laboratory experiments in order to isolate certain influential, context dependent components

Today I read a paper titled “Herding the Crowd: Automated Planning for Crowdsourced Planning”

The abstract is:
There has been significant interest in crowdsourcing and human computation

One subclass of human computation applications are those directed at tasks that involve planning (e.g

travel planning) and scheduling (e.g

conference scheduling)

Much of this work appears outside the traditional automated planning forums, and at the outset it is not clear whether automated planning has much of a role to play in these human computation systems

Interestingly however, work on these systems shows that even primitive forms of automated oversight of the human planner does help in significantly improving the effectiveness of the humans/crowd

In this paper, we will argue that the automated oversight used in these systems can be viewed as a primitive automated planner, and that there are several opportunities for more sophisticated automated planning in effectively steering crowdsourced planning

Straightforward adaptation of current planning technology is however hampered by the mismatch between the capabilities of human workers and automated planners

We identify two important challenges that need to be overcome before such adaptation of planning technology can occur: (i) interpreting the inputs of the human workers (and the requester) and (ii) steering or critiquing the plans being produced by the human workers armed only with incomplete domain and preference models

In this paper, we discuss approaches for handling these challenges, and characterize existing human computation systems in terms of the specific choices they make in handling these challenges

Today I read a paper titled “A new muscle fatigue and recovery model and its ergonomics application in human simulation”

The abstract is:
Although automatic techniques have been employed in manufacturing industries to increase productivity and efficiency, there are still lots of manual handling jobs, especially for assembly and maintenance jobs

In these jobs, musculoskeletal disorders (MSDs) are one of the major health problems due to overload and cumulative physical fatigue

With combination of conventional posture analysis techniques, digital human modelling and simulation (DHM) techniques have been developed and commercialized to evaluate the potential physical exposures

However, those ergonomics analysis tools are mainly based on posture analysis techniques, and until now there is still no fatigue index available in the commercial software to evaluate the physical fatigue easily and quickly

In this paper, a new muscle fatigue and recovery model is proposed and extended to evaluate joint fatigue level in manual handling jobs

A special application case is described and analyzed by digital human simulation technique

Today I read a paper titled “Let Us Dance Just a Little Bit More — On the Information Capacity of the Human Motor System”

The abstract is:
Fitts’ law is a fundamental tool in measuring the capacity of the human motor system

However, it is, by definition, limited to aimed movements toward spatially expanded targets

We revisit its information-theoretic basis with the goal of generalizing it into unconstrained trained movement such as dance and sports

The proposed new measure is based on a subject’s ability to accurately reproduce a complex movement pattern

We demonstrate our framework using motion-capture data from professional dance performances

Today I read a paper titled “Cutaneous Force Feedback as a Sensory Subtraction Technique in Haptics”

The abstract is:
A novel sensory substitution technique is presented

Kinesthetic and cutaneous force feedback are substituted by cutaneous feedback (CF) only, provided by two wearable devices able to apply forces to the index finger and the thumb, while holding a handle during a teleoperation task

The force pattern, fed back to the user while using the cutaneous devices, is similar, in terms of intensity and area of application, to the cutaneous force pattern applied to the finger pad while interacting with a haptic device providing both cutaneous and kinesthetic force feedback

The pattern generated using the cutaneous devices can be thought as a subtraction between the complete haptic feedback (HF) and the kinesthetic part of it

For this reason, we refer to this approach as sensory subtraction instead of sensory substitution

A needle insertion scenario is considered to validate the approach

The haptic device is connected to a virtual environment simulating a needle insertion task

Experiments show that the perception of inserting a needle using the cutaneous-only force feedback is nearly indistinguishable from the one felt by the user while using both cutaneous and kinesthetic feedback

As most of the sensory substitution approaches, the proposed sensory subtraction technique also has the advantage of not suffering from stability issues of teleoperation systems due, for instance, to communication delays

Moreover, experiments show that the sensory subtraction technique outperforms sensory substitution with more conventional visual feedback (VF)