Archives for 2015

Today I read a paper titled “Human Muscle Fatigue Model in Dynamic Motions”

The abstract is:
Human muscle fatigue is considered to be one of the main reasons for Musculoskeletal Disorder (MSD)

Recent models have been introduced to define muscle fatigue for static postures

However, the main drawbacks of these models are that the dynamic effect of the human and the external load are not taken into account

In this paper, each human joint is assumed to be controlled by two muscle groups to generate motions such as push/pull

The joint torques are computed using Lagrange’s formulation to evaluate the dynamic factors of the muscle fatigue model

An experiment is defined to validate this assumption and the result for one person confirms its feasibility

The evaluation of this model can predict the fatigue and MSD risk in industry production quickly

Today I read a paper titled “An Approximation Algorithm for Computing Shortest Paths in Weighted 3-d Domains”

The abstract is:
We present the first polynomial time approximation algorithm for computing shortest paths in weighted three-dimensional domains

The efficiency of the proposed algorithm is based on an in-depth study of the local behavior of geodesic paths and additive Voronoi diagrams in weighted three-dimensional domains, which are of independent interest

The paper extends the results of Aleksandrov, Maheshwari and Sack [JACM 2005] to three dimensions

Today I read a paper titled “Depth-Optimized Reversible Circuit Synthesis”

The abstract is:
In this paper, simultaneous reduction of circuit depth and synthesis cost of reversible circuits in quantum technologies with limited interaction is addressed

We developed a cycle-based synthesis algorithm which uses negative controls and limited distance between gate lines

To improve circuit depth, a new parallel structure is introduced in which before synthesis a set of disjoint cycles are extracted from the input specification and distributed into some subsets

The cycles of each subset are synthesized independently on different sets of ancillae

Accordingly, each disjoint set can be synthesized by ?different synthesis methods

Our analysis shows that the best worst-case synthesis cost of reversible circuits in the linear nearest neighbor architecture is improved by the proposed approach

Our experimental results reveal the effectiveness of the proposed approach to reduce cost and circuit depth for several benchmarks

Today I read a paper titled “A Very Simple Approach for 3-D to 2-D Mapping”

The abstract is:
Many times we need to plot 3-D functions e.g., in many scientificc experiments

To plot this 3-D functions on 2-D screen it requires some kind of mapping

Though OpenGL, DirectX etc 3-D rendering libraries have made this job very simple, still these libraries come with many complex pre- operations that are simply not intended, also to integrate these libraries with any kind of system is often a tough trial

This article presents a very simple method of mapping from 3D to 2D, that is free from any complex pre-operation, also it will work with any graphics system where we have some primitive 2-D graphics function

Also we discuss the inverse transform and how to do basic computer graphics transformations using our coordinate mapping system

Today I read a paper titled “Attention-Sensitive Alerting”

The abstract is:
We introduce utility-directed procedures for mediating the flow of potentially distracting alerts and communications to computer users

We present models and inference procedures that balance the context-sensitive costs of deferring alerts with the cost of interruption

We describe the challenge of reasoning about such costs under uncertainty via an analysis of user activity and the content of notifications

After introducing principles of attention-sensitive alerting, we focus on the problem of guiding alerts about email messages

We dwell on the problem of inferring the expected criticality of email and discuss work on the Priorities system, centering on prioritizing email by criticality and modulating the communication of notifications to users about the presence and nature of incoming email

Today I read a paper titled “Real-Time Human-Computer Interaction Based on Face and Hand Gesture Recognition”

The abstract is:
At the present time, hand gestures recognition system could be used as a more expected and useable approach for human computer interaction

Automatic hand gesture recognition system provides us a new tactic for interactive with the virtual environment

In this paper, a face and hand gesture recognition system which is able to control computer media player is offered

Hand gesture and human face are the key element to interact with the smart system

We used the face recognition scheme for viewer verification and the hand gesture recognition in mechanism of computer media player, for instance, volume down/up, next music and etc

In the proposed technique, first, the hand gesture and face location is extracted from the main image by combination of skin and cascade detector and then is sent to recognition stage

In recognition stage, first, the threshold condition is inspected then the extracted face and gesture will be recognized

In the result stage, the proposed technique is applied on the video dataset and the high precision ratio acquired

Additional the recommended hand gesture recognition method is applied on static American Sign Language (ASL) database and the correctness rate achieved nearby 99.40%

also the planned method could be used in gesture based computer games and virtual reality

Today I read a paper titled “Mechanism Design for Team Formation”

The abstract is:
Team formation is a core problem in AI

Remarkably, little prior work has addressed the problem of mechanism design for team formation, accounting for the need to elicit agents’ preferences over potential teammates

Coalition formation in the related hedonic games has received much attention, but only from the perspective of coalition stability, with little emphasis on the mechanism design objectives of true preference elicitation, social welfare, and equity

We present the first formal mechanism design framework for team formation, building on recent combinatorial matching market design literature

We exhibit four mechanisms for this problem, two novel, two simple extensions of known mechanisms from other domains

Two of these (one new, one known) have desirable theoretical properties

However, we use extensive experiments to show our second novel mechanism, despite having no theoretical guarantees, empirically achieves good incentive compatibility, welfare, and fairness.

Today I read a paper titled “Node Classification in Social Networks”

The abstract is:
When dealing with large graphs, such as those that arise in the context of online social networks, a subset of nodes may be labeled

These labels can indicate demographic values, interest, beliefs or other characteristics of the nodes (users)

A core problem is to use this information to extend the labeling so that all nodes are assigned a label (or labels)

In this chapter, we survey classification techniques that have been proposed for this problem

We consider two broad categories: methods based on iterative application of traditional classifiers using graph information as features, and methods which propagate the existing labels via random walks

We adopt a common perspective on these methods to highlight the similarities between different approaches within and across the two categories

We also describe some extensions and related directions to the central problem of node classification

Today I read a paper titled “How Many Nodes are Effectively Accessed in Complex Networks?”

The abstract is:
The measurement called accessibility has been proposed as a means to quantify the efficiency of the communication between nodes in complex networks

This article reports important results regarding the properties of the accessibility, including its relationship with the average minimal time to visit all nodes reachable after $h$ steps along a random walk starting from a source, as well as the number of nodes that are visited after a finite period of time

We characterize the relationship between accessibility and the average number of walks required in order to visit all reachable nodes (the exploration time), conjecture that the maximum accessibility implies the minimal exploration time, and confirm the relationship between the accessibility values and the number of nodes visited after a basic time unit

The latter relationship is investigated with respect to three types of dynamics, namely: traditional random walks, self-avoiding random walks, and preferential random walks

Today I read a paper titled “Review of simulating four classes of window materials for daylighting with non-standard BSDF using the simulation program Radiance”

The abstract is:
This review describes the currently available simulation models for window material to calculate daylighting with the program “Radiance”

The review is based on four abstract and general classes of window materials, depending on their scattering and redirecting properties (bidirectional scatter distribution function, BSDF)

It lists potential and limits of the older models and includes the most recent additions to the software

All models are demonstrated using an exemplary indoor scene and two typical sky conditions

It is intended as clarification for applying window material models in project work or teaching

The underlying algorithmic problems apply to all lighting simulation programs, so the scenarios of materials and skies are applicable to other lighting programs

Today I read a paper titled “Video Chat with Multiple Cameras”

The abstract is:
The dominant paradigm for video chat employs a single camera at each end of the conversation, but some conversations can be greatly enhanced by using multiple cameras at one or both ends

This paper provides the first rigorous investigation of multi-camera video chat, concentrating especially on the ability of users to switch between views at either end of the conversation

A user study of 23 individuals analyzes the advantages and disadvantages of permitting a user to switch between views at a remote location

Benchmark experiments employing up to four webcams simultaneously demonstrate that multi-camera video chat is feasible on consumer hardware

The paper also presents the design of MultiCam, a software package permitting multi-camera video chat

Some important trade-offs in the design of MultiCam are discussed, and typical usage scenarios are analyzed

Today I read a paper titled “Toric degenerations of Bezier patches”

The abstract is:
The control polygon of a Bezier curve is well-defined and has geometric significance—there is a sequence of weights under which the limiting position of the curve is the control polygon

For a Bezier surface patch, there are many possible polyhedral control structures, and none are canonical

We propose a not necessarily polyhedral control structure for surface patches, regular control surfaces, which are certain C^0 spline surfaces

While not unique, regular control surfaces are exactly the possible limiting positions of a Bezier patch when the weights are allowed to vary

Today I read a paper titled “Opinions within Media, Power and Gossip”

The abstract is:
Despite the increasing diffusion of the Internet technology, TV remains the principal medium of communication

People’s perceptions, knowledge, beliefs and opinions about matter of facts get (in)formed through the information reported on by the mass-media

However, a single source of information (and consensus) could be a potential cause of anomalies in the structure and evolution of a society

Hence, as the information available (and the way it is reported) is fundamental for our perceptions and opinions, the definition of conditions allowing for a good information to be disseminated is a pressing challenge

In this paper starting from a report on the last Italian political campaign in 2008, we derive a socio-cognitive computational model of opinion dynamics where agents get informed by different sources of information

Then, a what-if analysis, performed trough simulations on the model’s parameters space, is shown

In particular, the scenario implemented includes three main streams of information acquisition, differing in both the contents and the perceived reliability of the messages spread

Agents’ internal opinion is updated either by accessing one of the information sources, namely media and experts, or by exchanging information with one another

They are also endowed with cognitive mechanisms to accept, reject or partially consider the acquired information

Today I read a paper titled “Sparsification of Motion-Planning Roadmaps by Edge Contraction”

The abstract is:
We present Roadmap Sparsification by Edge Contraction (RSEC), a simple and effective algorithm for reducing the size of a motion-planning roadmap

The algorithm exhibits minimal effect on the quality of paths that can be extracted from the new roadmap

The primitive operation used by RSEC is edge contraction – the contraction of a roadmap edge to a single vertex and the connection of the new vertex to the neighboring vertices of the contracted edge

For certain scenarios, we compress more than 98% of the edges and vertices at the cost of degradation of average shortest path length by at most 2%

Today I read a paper titled “Fully Automatic Expression-Invariant Face Correspondence”

The abstract is:
We consider the problem of computing accurate point-to-point correspondences among a set of human face scans with varying expressions

Our fully automatic approach does not require any manually placed markers on the scan

Instead, the approach learns the locations of a set of landmarks present in a database and uses this knowledge to automatically predict the locations of these landmarks on a newly available scan

The predicted landmarks are then used to compute point-to-point correspondences between a template model and the newly available scan

To accurately fit the expression of the template to the expression of the scan, we use as template a blendshape model

Our algorithm was tested on a database of human faces of different ethnic groups with strongly varying expressions

Experimental results show that the obtained point-to-point correspondence is both highly accurate and consistent for most of the tested 3D face models

Today I read a paper titled “Neural Networks in Mobile Robot Motion”

The abstract is:
This paper deals with a path planning and intelligent control of an autonomous robot which should move safely in partially structured environment

This environment may involve any number of obstacles of arbitrary shape and size; some of them are allowed to move

We describe our approach to solving the motion-planning problem in mobile robot control using neural networks-based technique

Our method of the construction of a collision-free path for moving robot among obstacles is based on two neural networks

The first neural network is used to determine the “free” space using ultrasound range finder data

The second neural network “finds” a safe direction for the next robot section of the path in the workspace while avoiding the nearest obstacles

Simulation examples of generated path with proposed techniques will be presented

Today I read a paper titled “iReclass – An automatic system for recording classes”

The abstract is:
This paper presents the details of a system capable of recording on video a traditional class

By traditional class it is meant a teacher, a blackboard and a white canvas where course notes are projected

The system is able to track the movements of the lecturer, while recording it on video at the required frame rate (e.g., 25 fps)

The system is also capable of understanding five arm gestures made by the lecturer with the intent of controlling which scenario is recorded: himself, the blackboard or the white canvas

The remaining two gestures are for start/stop the recorder

The system is composed by a Kinect sensor, a video camera, a microphone, one pan-tilt system and one pan system, using a total of three step motors

Today I read a paper titled “A Health Monitoring System for Elder and Sick Persons”

The abstract is:
This paper discusses a vision based health monitoring system which would be very easy in use and deployment

Elder and sick people who are not able to talk or walk they are dependent on other human beings for their daily needs and need continuous monitoring

The developed system provides facility to the sick or elder person to describe his or her need to their caretaker in lingual description by showing particular hand gesture with the developed system

This system uses fingertip detection technique for gesture extraction and artificial neural network for gesture classification and recognition

The system is able to work in different light conditions and can be connected to different devices to announce users need on a distant location

Today I read a paper titled “Dependence Maximizing Temporal Alignment via Squared-Loss Mutual Information”

The abstract is:
The goal of temporal alignment is to establish time correspondence between two sequences, which has many applications in a variety of areas such as speech processing, bioinformatics, computer vision, and computer graphics

In this paper, we propose a novel temporal alignment method called least-squares dynamic time warping (LSDTW)

LSDTW finds an alignment that maximizes statistical dependency between sequences, measured by a squared-loss variant of mutual information

The benefit of this novel information-theoretic formulation is that LSDTW can align sequences with different lengths, different dimensionality, high non-linearity, and non-Gaussianity in a computationally efficient manner

In addition, model parameters such as an initial alignment matrix can be systematically optimized by cross-validation

We demonstrate the usefulness of LSDTW through experiments on synthetic and real-world Kinect action recognition datasets

Today I read a paper titled “Providing Long-Term Participation Incentive in Participatory Sensing”

The abstract is:
Providing an adequate long-term participation incentive is important for a participatory sensing system to maintain enough number of active users (sensors), so as to collect a sufficient number of data samples and support a desired level of service quality

In this work, we consider the sensor selection problem in a general time-dependent and location-aware participatory sensing system, taking the long-term user participation incentive into explicit consideration

We study the problem systematically under different information scenarios, regarding both future information and current information (realization)

In particular, we propose a Lyapunov-based VCG auction policy for the on-line sensor selection, which converges asymptotically to the optimal off-line benchmark performance, even with no future information and under (current) information asymmetry

Extensive numerical results show that our proposed policy outperforms the state-of-art policies in the literature, in terms of both user participation (e.g., reducing the user dropping probability by 25% to 90%) and social performance (e.g., increasing the social welfare by 15% to 80%).

Today I read a paper titled “Mobile Augmented Reality Applications”

The abstract is:
Augmented reality have undergone considerable improvement in past years

Many special techniques and hardware devices were developed, but the crucial breakthrough came with the spread of intelligent mobile phones

This enabled mass spread of augmented reality applications

However mobile devices have limited hardware capabilities, which narrows down the methods usable for scene analysis

In this article we propose an augmented reality application which is using cloud computing to enable using of more complex computational methods such as neural networks

Our goal is to create an affordable augmented reality application suitable which will help car designers in by ‘virtualizing’ car modifications

Today I read a paper titled “From individual to population: Challenges in Medical Visualization”

The abstract is:
In this paper, we first give a high-level overview of medical visualization development over the past 30 years, focusing on key developments and the trends that they represent

During this discussion, we will refer to a number of key papers that we have also arranged on the medical visualization research timeline

Based on the overview and our observations of the field, we then identify and discuss the medical visualization research challenges that we foresee for the coming decade

Today I read a paper titled “Social network dynamics of face-to-face interactions”

The abstract is:
The recent availability of data describing social networks is changing our understanding of the “microscopic structure” of a social tie

A social tie indeed is an aggregated outcome of many social interactions such as face-to-face conversations or phone-calls

Analysis of data on face-to-face interactions shows that such events, as many other human activities, are bursty, with very heterogeneous durations

In this paper we present a model for social interactions at short time scales, aimed at describing contexts such as conference venues in which individuals interact in small groups

We present a detailed anayltical and numerical study of the model’s dynamical properties, and show that it reproduces important features of empirical data

The model allows for many generalizations toward an increasingly realistic description of social interactions

In particular in this paper we investigate the case where the agents have intrinsic heterogeneities in their social behavior, or where dynamic variations of the local number of individuals are included

Finally we propose this model as a very flexible framework to investigate how dynamical processes unfold in social networks