26 research outputs found
Asynchronous Gathering of Robots with Finite Memory on a Circle under Limited Visibility
Consider a set of mobile entities, called robots, located and operating
on a continuous circle, i.e., all robots are initially in distinct locations on
a circle. The \textit{gathering} problem asks to design a distributed algorithm
that allows the robots to assemble at a point on the circle. Robots are
anonymous, identical, and homogeneous. Robots operate in a deterministic
Look-Compute-Move cycle within the circular path. Robots agree on the clockwise
direction. The robot's movement is rigid and they have limited visibility
, i.e., each robot can only see the points of the circle which is at an
angular distance strictly less than from the robot.
Di Luna \textit{et al}. [DISC'2020] provided a deterministic gathering
algorithm of oblivious and silent robots on a circle in semi-synchronous
(\textsc{SSync}) scheduler. Buchin \textit{et al}. [IPDPS(W)'2021] showed that,
under full visibility, robot model with \textsc{SSync}
scheduler is incomparable to robot (robots are silent but have
finite persistent memory) model with asynchronous (\textsc{ASync}) scheduler.
Under limited visibility, this comparison is still unanswered. So, this work
extends the work of Di Luna \textit{et al}. [DISC'2020] under \textsc{ASync}
scheduler for robot model
USABILITY OF E-RESOURCES AMONG LIBRARY & INFORMATION SCIENCE STUDENTS IN PATNA, BIHAR: A STUDY
The research aims into library science students at Patna University in Bihar\u27s understanding and use of electronic resources and many other relevant topics. In this investigation, the researcher adopted a descriptive strategy. The main objective of the paper is to get an understanding of the use of electronic resources by the library user. Overall, 90 questionnaires were distributed, whereas only 72 were filled and returned as a sample. To collect data from the users, a systematic questionnaire was constructed. The study aimed to determine the users\u27 requirements and level of consciousness and use of electronic resources. According to data, many users were satisfied with infrastructure facilities, required information, or other reasons for using e-resources and services. However, some users could not use the e-resources due to the lack of user education and awareness campaigns, language difficulties, and IT skills and understanding. As a result, libraries should actively launch well-planned user awareness and education initiatives, expand infrastructure, and subscribe to more e-resources
Role of saline infusion sonography in evaluation of abnormal uterine bleeding
Background: Abnormal uterine bleeding (AUB) is one of the most common reasons for women seeking gynaecological advice. The objective of this study was to determine the accuracy of Transvaginal sonography (TVS) and Saline Infusion Sonography (SIS) in evaluation of Abnormal Uterine Bleeding (AUB) and to compare the diagnostic accuracy after hysterectomy.Methods: Prospective, comparative study of TVS and SIS in evaluation of AUB in patients who are being subjected to hysterectomy with uterus of less than 12 weeks.Results: 100 patients were included in the study. 98% were of 30-50 years. Heavy menstrual bleeding was the commonest symptom (52%) and most common finding was fibroid, and Polyp followed by abnormal endometrium. The overall sensitivity and specificity when correlated with operative and HPE were 66% and 88% respectively for TVS and 82% and 95% for SIS respectively. The false positive and false negative rates were more in TVS compared to SIS. Commonest histopathology was intramural fibroid in 42% followed by sub mucus myoma in 21%, polyp 18% and endometrial hyperplasia 10%.Conclusions: SIS is a simple highly sensitive and specific technique to detect intra uterine pathology in the evaluation of AUB when TVS findings are inconclusive
A Review of Second Generation of Terrestrial Digital Video Broadcasting System
Digital broadcast systems have increasingly been deployed for various services such as Digital Video Broadcasting (i.e. DVB-S, DVB-T, etc.) and Digital Audio Broadcasting (DAB). Classical digital broadcast systems were designed with fixed modulation guarantee reliable communication even with very hostile channel environment. DVB-T2 terrestrial television standard is becoming increasingly important. The emergence of it is motivated by the higher spectral efficiency and adopting transition from analogue TV to DVB-T2, or transition from DVB-T to DVB-T2. It can reduce the transmission cost per program and deliver HD services economically viable. It introduces a new technique to improve performance in channels with frequency selective fading. If in addition improved source coding (MPEG-4) is employed, the gain in broadcast transmission is remarkable. Keywords: DVB-T, DVB-T2, Digital video broadcastin
Rendezvous on a Known Dynamic Point on a Finite Unoriented Grid
In this paper, we have considered two fully synchronous
robots having no agreement on coordinates entering a finite unoriented grid
through a door vertex at a corner, one by one. There is a resource that can
move around the grid synchronously with the robots until it gets co-located
along with at least one robot. Assuming the robots can see and identify the
resource, we consider the problem where the robots must meet at the location of
this dynamic resource within finite rounds. We name this problem "Rendezvous on
a Known Dynamic Point".
Here, we have provided an algorithm for the two robots to gather at the
location of the dynamic resource. We have also provided a lower bound on time
for this problem and showed that with certain assumption on the waiting time of
the resource on a single vertex, the algorithm provided is time optimal. We
have also shown that it is impossible to solve this problem if the scheduler
considered is semi-synchronous
Space and move-optimal Arbitrary Pattern Formation on infinite rectangular grid by Oblivious Robot Swarm
Arbitrary Pattern Formation (APF) is a fundamental coordination problem in
swarm robotics. It requires a set of autonomous robots (mobile computing units)
to form any arbitrary pattern (given as input) starting from any initial
pattern. The APF problem is well-studied in both continuous and discrete
settings. This work concerns the discrete version of the problem. A set of
robots is placed on the nodes of an infinite rectangular grid graph embedded in
a euclidean plane. The movements of the robots are restricted to one of the
four neighboring grid nodes from its current position. The robots are
autonomous, anonymous, identical, and homogeneous, and operate
Look-Compute-Move cycles. Here we have considered the classical
robot model, i.e., the robots have no persistent memory and
no explicit means of communication. The robots have full unobstructed
visibility. This work proposes an algorithm that solves the APF problem in a
fully asynchronous scheduler under this setting assuming the initial
configuration is asymmetric. The considered performance measures of the
algorithm are space and number of moves required for the robots. The algorithm
is asymptotically move-optimal. A definition of the space-complexity is
presented here. We observe an obvious lower bound of the space
complexity and show that the proposed algorithm has the space complexity
. On comparing with previous related works, we show that this is
the first proposed algorithm considering robot model that is
asymptotically move-optimal and has the least space complexity which is almost
optimal
Circle Formation by Asynchronous Opaque Fat Robots on an Infinite Grid
This study addresses the problem of "Circle Formation on an Infinite Grid by
Fat Robots" (). Unlike prior work focused solely on point robots
in discrete domain, it introduces fat robots to circle formation on an infinite
grid, aligning with practicality as even small robots inherently possess
dimensions. The algorithm, named , resolves the
problem using a swarm of fat luminous robots. Operating under an asynchronous
scheduler, it achieves this with five distinct colors and by leveraging
one-axis agreement among the robots
Room-Temperature Anomalous Hall Effect in Graphene in Interfacial Magnetic Proximity with EuO Grown by Topotactic Reduction
We show that thin layers of EuO, a ferromagnetic insulator, can be achieved
by topotactic reduction under titanium of a Eu2O3 film deposited on top of a
graphene template. The reduction process leads to the formation of a 7-nm thick
EuO smooth layer, without noticeable structural changes in the underlying
chemical vapor deposited (CVD) graphene. The obtained EuO films exhibit
ferromagnetism, with a Curie temperature that decreases with the initially
deposited Eu2O3 layer thickness. By adjusting the thickness of the Eu2O3 layer
below 7 nm, we promote the formation of EuO at the very graphene interface: the
EuO/graphene heterostructure demonstrates the anomalous Hall effect (AHE),
which is a fingerprint of proximity-induced spin polarization in graphene. The
AHE signal moreover persists above Tc up to 350K due to a robust
super-paramagnetic phase in EuO. This original high-temperature magnetic phase
is attributed to magnetic polarons in EuO: we propose that the high strain in
our EuO films grown on graphene stabilizes the magnetic polarons up to room
temperature. This effect is different from the case of bulk EuO in which
polarons vanish in the vicinity of the Curie temperature Tc= 69K.Comment: 29 page
Time Optimal Gathering of Robots on an Infinite Triangular Grid with Limited Visibility
This work deals with the problem of gathering of oblivious mobile
entities, called robots, with limited visibility, at a point (not known
beforehand) placed on an infinite triangular grid. Earlier works of gathering
mostly considered the robots either on a plane or on a circle or on a
rectangular grid under both full and limited visibility. In the triangular
grid, there are two works to the best of our knowledge. The first one is
arbitrary pattern formation where full visibility is considered (\cite{C21}).
The other one considers seven robots with 2- hop visibility that form a hexagon
with one robot in the center of the hexagon in a collision-less environment
under a fully synchronous scheduler (\cite{ShibataOS00K21}).
In this work, we first show that gathering on a triangular grid with 1-hop
vision of robots is not possible even under a fully synchronous scheduler if
the robots do not agree on any axis. So one axis agreement has been considered
in this work (i.e., the robots agree on a direction and its orientation). We
have also showed that the lower bound for time is epochs when
number of robots are gathering on an infinite triangular grid. An algorithm is
then presented where a swarm of number of robots with 1-hop visibility can
gather within epochs under a semi-synchronous scheduler. So the
algorithm presented here is time optimal