1,327 research outputs found
Partitioning de Bruijn Graphs into Fixed-Length Cycles for Robot Identification and Tracking
We propose a new camera-based method of robot identification, tracking and
orientation estimation. The system utilises coloured lights mounted in a circle
around each robot to create unique colour sequences that are observed by a
camera. The number of robots that can be uniquely identified is limited by the
number of colours available, , the number of lights on each robot, , and
the number of consecutive lights the camera can see, . For a given set of
parameters, we would like to maximise the number of robots that we can use. We
model this as a combinatorial problem and show that it is equivalent to finding
the maximum number of disjoint -cycles in the de Bruijn graph
.
We provide several existence results that give the maximum number of cycles
in in various cases. For example, we give an optimal
solution when . Another construction yields many cycles in larger
de Bruijn graphs using cycles from smaller de Bruijn graphs: if
can be partitioned into -cycles, then
can be partitioned into -cycles for any divisor of
. The methods used are based on finite field algebra and the combinatorics
of words.Comment: 16 pages, 4 figures. Accepted for publication in Discrete Applied
Mathematic
High sensitivity and multifunctional micro-Hall sensors fabricated using InAlSb/InAsSb/InAlSb heterostructures
Further diversification of Hall sensor technology requires development of materials with high electron mobility and an ultrathin conducting layer very close to the material's surface. Here, we describe the magnetoresistive properties of micro-Hall devices fabricated using InAlSb/InAsSb/InAlSb heterostructures where electrical conduction was confined to a 30 nm-InAsSb two-dimensional electron gas layer. The 300 K electron mobility and sheet carrier concentration were 36 500 cm(2) V-1 s(-1) and 2.5 x 10(11) cm(-2), respectively. The maximum current-related sensitivity was 2 750 V A(-1) T-1, which was about an order of magnitude greater than AlGaAs/InGaAs pseudomorphic heterostructures devices. Photolithography was used to fabricate 1 mu m x 1 mu m Hall probes, which were installed into a scanning Hall probe microscope and used to image the surface of a hard disk
Hybrid FPMS: A New Fairness Protocol Management Scheme for Community Wireless Mesh Networks
Node cooperation during packet forwarding operations is critically important
for fair resource utilization in Community Wireless Mesh Networks (CoWMNs). In
a CoWMN, node cooperation is achieved by using fairness protocols specifically
designed to detect and isolate malicious nodes, discourage unfair behavior, and
encourage node participation in forwarding packets. In general, these protocols
can be split into two groups: Incentive-based ones, which are managed
centrally, and use credit allocation schemes. In contrast, reputation-based
protocols that are decentralized, and rely on information exchange among
neighboring nodes. Centrally managed protocols inevitably suffer from
scalability problems. The decentralized, reputation-based protocols lacks in
detection capability, suffer from false detections and error propagation
compared to the centralized, incentive-based protocols. In this study, we
present a new fairness protocol management scheme, called Hybrid FPMS that
captures the superior detection capability of incentive-based fairness
protocols without the scalability problems inherently expected from a
centralized management scheme as a network's size and density grows. Simulation
results show that Hybrid FPMS is more efficient than the current centralized
approach and significantly reduces the network delays and overhead.Comment: KSII Transactions on Internet and Information Systems, 201
van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices
Due to the chemical inertness of 2D hexagonal-Boron Nitride (h-BN), few
atomic-layer h-BN is often used to encapsulate air-sensitive 2D crystals such
as Black Phosphorus (BP). However, the effects of h-BN on Schottky barrier
height, doping and contact resistance are not well known. Here, we investigate
these effects by fabricating h-BN encapsulated BP transistors with cobalt (Co)
contacts. In sharp contrast to directly Co contacted p-type BP devices, we
observe strong n-type conduction upon insertion of the h-BN at the Co/BP
interface. First principles calculations show that this difference arises from
the much larger interface dipole at the Co/h-BN interface compared to the Co/BP
interface, which reduces the work function of the Co/h-BN contact. The Co/h-BN
contacts exhibit low contact resistances (~ 4.5 k-ohm), and are Schottky
barrier free. This allows us to probe high electron mobilities (4,200 cm2/Vs)
and observe insulator-metal transitions even under two-terminal measurement
geometry
Jute and luffa fiber-reinforced biocomposites: Effects of sample thickness and fiber/resin ratio on sound absorption and transmission Loss Performance
The acoustic properties of natural fiber-reinforced composites should be identified before using these materials in various engineering applications including sound and vibration isolation. This study investigates the effects of sample thickness and fiber/resin ratio on the acoustic performance of jute and luffa fiber-reinforced biocomposites. For this purpose, jute and luffa composite samples with different thicknesses and fiber/epoxy ratios are manufactured and their sound absorption coefficients (SACs) and transmission losses (TLs) are determined using impedance tube method. Thickness-dependent tendencies of the SACs and TLs of jute and luffa composites for low-, medium-, and high-frequency ranges are identified. The effect of fiber/epoxy ratio on the acoustic properties of jute and luffa composites as a function of frequency are determined. Furthermore, the SACs and TLs of some natural fiber-based samples with different thicknesses are predicted using mathematical models and the theoretical and experimental results are compared and evaluated.TUBITAK (The Scientific and Technological Research Council of Turkey) under Grant
119M115.WOS:000638569100001Scopus - Affiliation ID: 60105072Science Citation Index ExpandedQ1Article; Early AccessUluslararası işbirliği ile yapılmayan - HAYIRNisan2021YÖK - 2020-2
Risk Factors for Trabeculotomy Failure in Primary Congenital Glaucoma
Précis: This study demonstrates that a baseline corneal diameter >12.25, initial age [removed]12.25 mm did by 4.2 times, younger age than 4 months did by 2.5 times, bilaterality did by 1.5 times. Conclusions: A higher baseline IOP, younger age, larger corneal diameter, and bilaterality were identified as risk factors for trabeculotomy failure in congenital glaucoma. The presence of one or more of these should be considered in the decision-making process when considering surgical options to manage glaucoma in these patients. © 2022 Wolters Kluwer Health, Inc. All rights reserved
Automated Inference System for End-To-End Diagnosis of Network Performance Issues in Client-Terminal Devices
Traditional network diagnosis methods of Client-Terminal Device (CTD)
problems tend to be laborintensive, time consuming, and contribute to increased
customer dissatisfaction. In this paper, we propose an automated solution for
rapidly diagnose the root causes of network performance issues in CTD. Based on
a new intelligent inference technique, we create the Intelligent Automated
Client Diagnostic (IACD) system, which only relies on collection of
Transmission Control Protocol (TCP) packet traces. Using soft-margin Support
Vector Machine (SVM) classifiers, the system (i) distinguishes link problems
from client problems and (ii) identifies characteristics unique to the specific
fault to report the root cause. The modular design of the system enables
support for new access link and fault types. Experimental evaluation
demonstrated the capability of the IACD system to distinguish between faulty
and healthy links and to diagnose the client faults with 98% accuracy. The
system can perform fault diagnosis independent of the user's specific TCP
implementation, enabling diagnosis of diverse range of client devicesComment: arXiv admin note: substantial text overlap with arXiv:1207.356
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