Gathering an even number of robots in an odd ring without global multiplicity detection

We propose a gathering protocol for an even number of robots in a ring-shaped network that allows symmetric but not periodic configurations as initial configurations, yet uses only local weak multiplicity detection. Robots are assumed to be anonymous and oblivious, and the execution model is the non- atomic CORDA model with asynchronous fair scheduling. In our scheme, the number of robots k must be greater than 8, the number of nodes n on a network must be odd and greater than k+3. The running time of our protocol is O(n2) asynchronous rounds.Comment: arXiv admin note: text overlap with arXiv:1104.566

Self-stabilizing algorithms for Connected Vertex Cover and Clique decomposition problems

In many wireless networks, there is no fixed physical backbone nor centralized network management. The nodes of such a network have to self-organize in order to maintain a virtual backbone used to route messages. Moreover, any node of the network can be a priori at the origin of a malicious attack. Thus, in one hand the backbone must be fault-tolerant and in other hand it can be useful to monitor all network communications to identify an attack as soon as possible. We are interested in the minimum \emph{Connected Vertex Cover} problem, a generalization of the classical minimum Vertex Cover problem, which allows to obtain a connected backbone. Recently, Delbot et al.~\cite{DelbotLP13} proposed a new centralized algorithm with a constant approximation ratio of $2$ for this problem. In this paper, we propose a distributed and self-stabilizing version of their algorithm with the same approximation guarantee. To the best knowledge of the authors, it is the first distributed and fault-tolerant algorithm for this problem. The approach followed to solve the considered problem is based on the construction of a connected minimal clique partition. Therefore, we also design the first distributed self-stabilizing algorithm for this problem, which is of independent interest

A Superstabilizing log⁡(n)\log(n)-Approximation Algorithm for Dynamic Steiner Trees

In this paper we design and prove correct a fully dynamic distributed algorithm for maintaining an approximate Steiner tree that connects via a minimum-weight spanning tree a subset of nodes of a network (referred as Steiner members or Steiner group) . Steiner trees are good candidates to efficiently implement communication primitives such as publish/subscribe or multicast, essential building blocks for the new emergent networks (e.g. P2P, sensor or adhoc networks). The cost of the solution returned by our algorithm is at most $\log |S|$ times the cost of an optimal solution, where $S$ is the group of members. Our algorithm improves over existing solutions in several ways. First, it tolerates the dynamism of both the group members and the network. Next, our algorithm is self-stabilizing, that is, it copes with nodes memory corruption. Last but not least, our algorithm is \emph{superstabilizing}. That is, while converging to a correct configuration (i.e., a Steiner tree) after a modification of the network, it keeps offering the Steiner tree service during the stabilization time to all members that have not been affected by this modification

Development of the Drive Dozing Prevention Technique Using a Sensor Installed in the Seat for Detecting the Driver’s Condition

International audienceIn this study, to propose a new data acquisition method for detecting the dozing symptom during wakeful state of a driver, magnetic and pneumatic sensors for extracting biological signals from the driver under the dynamic seated condition, a suspension with a combination of a magnetic spring and a damper to avoid cruel disturbance input from the floor are developed. To estimate emerging timing of sleep detecting signal, chaos analysis was employed which yields the largest Lyapunov exponent and the power from measured pulse waves. By making use of the information of the sleep herald phenomenon and sleep latent time, the relation of sleep latent time with medical parameters closely related to a muscle fatigue was found

Rendezvous of Two Robots with Constant Memory

We study the impact that persistent memory has on the classical rendezvous problem of two mobile computational entities, called robots, in the plane. It is well known that, without additional assumptions, rendezvous is impossible if the entities are oblivious (i.e., have no persistent memory) even if the system is semi-synchronous (SSynch). It has been recently shown that rendezvous is possible even if the system is asynchronous (ASynch) if each robot is endowed with O(1) bits of persistent memory, can transmit O(1) bits in each cycle, and can remember (i.e., can persistently store) the last received transmission. This setting is overly powerful. In this paper we weaken that setting in two different ways: (1) by maintaining the O(1) bits of persistent memory but removing the communication capabilities; and (2) by maintaining the O(1) transmission capability and the ability to remember the last received transmission, but removing the ability of an agent to remember its previous activities. We call the former setting finite-state (FState) and the latter finite-communication (FComm). Note that, even though its use is very different, in both settings, the amount of persistent memory of a robot is constant. We investigate the rendezvous problem in these two weaker settings. We model both settings as a system of robots endowed with visible lights: in FState, a robot can only see its own light, while in FComm a robot can only see the other robot's light. We prove, among other things, that finite-state robots can rendezvous in SSynch, and that finite-communication robots are able to rendezvous even in ASynch. All proofs are constructive: in each setting, we present a protocol that allows the two robots to rendezvous in finite time.Comment: 18 pages, 3 figure

"A Free thenar flap – A case report"

We present a case report of a free thenar flap surgery done for a volar right hand middle finger, distal and middle phalanx degloving injury. A free thenar flap is a fasciocutaneous sensate flap supplied by a constant branch of the superficial radial artery and its variable nerve supply. It has a distinct advantage of low donor site morbidity, better cosmesis and texture of the flap. No immobilization is required postop. The donor site can be closed primiarily

Statistical relationship between date of sowing and the sorghum shootfly (Atherigona Soccata, Rondani L)

The present study was based on the available data of eleven years for shoot fly from 2000-2010 for kharif season. Different models viz., linear and non linear were tried to fit, Amongst, the linear, quadratic and cubic models produced better coefficient of determination and the models viz., EGG(Shoot fly Egg) =3.760+0.196(DOS) (R2 =0.892) and EGG(Shoot fly Egg) =1.077+1.195(DOS)-0.087(DOS^2), which produced highest R2 (0.896 at p=0.05) with less standard error (0.419) and quadratic model was also the best fit model in determining the oviposition of shoot fly, which explained 89.6 per cent variation in the oviposition of shoot fly for the 7 days after emergence of the sorghum crop. For the dead heart development (14 DAE), the model %DH (% Dead Heart) =3.535+3.104(DOS) found best fit with highest coefficient of determination of 0. 856 and exhibited significant positive relationship with the date of sowing and during 21 DAE the cubic model %DH (% Dead Heart) =10.619+10.115(DOS)-3.466(DOS^2)+0 .321(DOS ^3) had significant coefficient of determination value of 0.988 with least standard error 0.885. The quadratic model during the 28 days after emergence of the crop %DH (% Dead Heart) =-6.234+22.858(DOS) -1.399 (DOS^2) found best fit and produced significant R2 (0.929 at 5 per cent level) and showed better relationship with the date of sowing. It was found that, both linear and non linear relationship exists between dates of sowing and shoot fly of sorghum during kharif season

Connecting ROS and FIWARE: Concepts and Tutorial

Nowadays, the Cloud technology permeates our daily life, spread in various services and applications used by modern instruments, such as smartphones, computer, and IoT devices. Besides, the robotic field represents one of the future emerging markets. Nevertheless, these two distinct worlds seem to be very far from each other, due to the lack of common strategies and standards. The aim of this tutorial chapter is to provide a walkthrough to build a basic Cloud Robotics application using ROS and the FIWARE Cloud framework. At the beginning, the chapter offers step-by-step instructions to create and manage an Orion Context Broker running on a virtual machine. Then, the firos package is used to integrate the ROS topic communication using publishers and subscribers, providing a clear example. Finally, a more concrete use case is detailed, developing a Cloud Robotics application to control a ROS-based robot through the FIWARE framework. The code of the present tutorial is available at https://github.com/Raffa87/ROS_FIWARE_Tutorial, tested using ROS Indigo