2,076 research outputs found

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

    Full text link
    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

    Global energetic neutral atom (ENA) measurements and their association with the Dst index

    Get PDF
    We present a new global magnetospheric index that measures the intensity of the Earth\u27s ring current through energetic neutral atoms (ENAs). We have named it the Global Energetic Neutral Index (GENI), and it is derived from ENA measurements obtained by the Imaging Proton Spectrometer (IPS), part of the Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment on the POLAR satellite. GENI provides a simple orbit-independent global sum of ENAs measured with IPS. Actual ENA measurements for the same magnetospheric state look different when seen from different points in the POLAR orbit. In addition, the instrument is sensitive to weak ion populations in the polar cap, as well as cosmic rays. We have devised a method for removing the effects of cosmic rays and weak ion fluxes, in order to produce an image of “pure” ENA counts. We then devised a method of normalizing the ENA measurements to remove the orbital bias effect. The normalized data were then used to produce the GENI. We show, both experimentally and theoretically the approximate proportionality between the GENI and the Dst index. In addition we discuss possible implications of this relation. Owing to the high sensitivity of IPS to ENAs, we can use these data to explore the ENA/Dst relationship not only during all phases of moderate geomagnetic storms, but also during quiescent ring current periods

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

    Get PDF
    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

    Full text link
    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

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

    Get PDF
    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
    corecore