1,733 research outputs found
Automatic Solar Tracking System with AVR Microcontroller based Street Light
This paper presents the design of a solar tracking system driven by an AVR microcontroller. This project is done by two ways of tracking system, manual and auto tracking. This project is very useful for street light in the campus and villages. The solar panel converts the sun light into the electrical energy, because sun is a very good source of different energies. And the solar energy is the best technique for renewable energy. Basically the energy sources are two types such as conventional energy sources and non-conventional energy sources. Coal, petroleum, natural gas etc. are example of conventional energy sources and solar cell, fuel cells, thermo-electric generator, thermionic converter, solar power generation, wind power generation, geo-thermal energy generation etc. are example of non-conventional energy sources. In developing countries where electricity supplies are inadequate, renewable energy can offer an alternative to expensive extensions of the grid to sparsely populated or rural areas, or a contribution to the grid-based energy mix to meet rapidly expanding electricity demand in urban areas. This work presents an autonomous street lighting system based on solar energy as primary source, batteries as secondary source, and light emitting diodes as lighting source. This system is being presented as an alternative for remote localities, like roads and crossroads
Quantum Lightning Never Strikes the Same State Twice
Public key quantum money can be seen as a version of the quantum no-cloning
theorem that holds even when the quantum states can be verified by the
adversary. In this work, investigate quantum lightning, a formalization of
"collision-free quantum money" defined by Lutomirski et al. [ICS'10], where
no-cloning holds even when the adversary herself generates the quantum state to
be cloned. We then study quantum money and quantum lightning, showing the
following results:
- We demonstrate the usefulness of quantum lightning by showing several
potential applications, such as generating random strings with a proof of
entropy, to completely decentralized cryptocurrency without a block-chain,
where transactions is instant and local.
- We give win-win results for quantum money/lightning, showing that either
signatures/hash functions/commitment schemes meet very strong recently proposed
notions of security, or they yield quantum money or lightning.
- We construct quantum lightning under the assumed multi-collision resistance
of random degree-2 systems of polynomials.
- We show that instantiating the quantum money scheme of Aaronson and
Christiano [STOC'12] with indistinguishability obfuscation that is secure
against quantum computers yields a secure quantum money schem
Planar Embeddings with Small and Uniform Faces
Motivated by finding planar embeddings that lead to drawings with favorable
aesthetics, we study the problems MINMAXFACE and UNIFORMFACES of embedding a
given biconnected multi-graph such that the largest face is as small as
possible and such that all faces have the same size, respectively.
We prove a complexity dichotomy for MINMAXFACE and show that deciding whether
the maximum is at most is polynomial-time solvable for and
NP-complete for . Further, we give a 6-approximation for minimizing
the maximum face in a planar embedding. For UNIFORMFACES, we show that the
problem is NP-complete for odd and even . Moreover, we
characterize the biconnected planar multi-graphs admitting 3- and 4-uniform
embeddings (in a -uniform embedding all faces have size ) and give an
efficient algorithm for testing the existence of a 6-uniform embedding.Comment: 23 pages, 5 figures, extended version of 'Planar Embeddings with
Small and Uniform Faces' (The 25th International Symposium on Algorithms and
Computation, 2014
Comparative Study between Mobile Operating Systems and Android Application Development
Android operating system is a broadened source versatile application which relies upon Linux Kernel working framework. It is most popular application till now and has a low cost which makes it growing much faster than any other operating system. In today’s world of rapidly growing technology there are many operating system but android is the most efficient and user friendly operating system. The main reason towards its growing popularity is various functionalities, ease of use and utility. This can perform numerous tasks such as making call, sending or receiving Messages, music, online shopping, playing games, web browsing, many social media apps etc. As we all know Android OS is developed by Google and provides a huge variety of applications. This paper will show the increase of Android OS and the development of Android operating system
Relationship between working capital management and profitability in JSE listed retail sector companies
Underwater Acoustic Sensor Network Data Optimization with Enhanced Void Avoidance and Routing Protocol
Deployment of a multi-hop underwater acoustic sensor network (UASN) in a larger region presents innovative challenges in reliable data communications and survivability of network because of the limited underwater interaction range or bandwidth and the limited energy of underwater sensor nodes. UASNs are becoming very significant in ocean exploration applications, like underwater device maintenance, ocean monitoring, ocean resource management, pollution detection, and so on. To overcome those difficulties and attains the purpose of maximizing data delivery ratio and minimizing energy consumption of underwater SNs, routing becomes necessary. In UASN, as the routing protocol will guarantee effective and reliable data communication from the source node to the destination, routing protocol model was an alluring topic for researchers. There were several routing techniques devised recently. This manuscript presents an underwater acoustic sensor network data optimization with enhanced void avoidance and routing (UASN-DAEVAR) protocol. The presented UASN-DAEVAR technique aims to present an effective data transmission process using proficient routing protocols. In the presented UASN-DAEVAR technique, a red deer algorithm (RDA) is employed in this study. In addition, the UASN-DAEVAR technique computes optimal routes in the UASN. To exhibit the effectual results of the UASN-DAEVAR technique, a wide spread experimental analysis is made. The experimental outcomes represented the enhancements of the UASN-DAEVAR model
PERFORMANCE CHARECTERISTICS OF TURBO VENTILATOR: A REVIEW
Turbo ventilator is an alternative to motor driven ventilating systems. The rooftop turbo ventilator is now widely accepted for industrial ventilation as well becomes important ventilation feature which is used for ventilation of commercial, residential and many institutional buildings. It works effectively at very low wind speeds hence always functional. Many researchers found that performance of turbo ventilator depends on its various operating parameters and environmental conditions. Therefore, study of turbo ventilators in details has become the focus area of research. In this paper detailed study about the current improvements and future scope of the turbo ventilator is done. The results of analytical and the experimental works are analyzed by considering its performance for the various applications
On Smooth Orthogonal and Octilinear Drawings: Relations, Complexity and Kandinsky Drawings
We study two variants of the well-known orthogonal drawing model: (i) the
smooth orthogonal, and (ii) the octilinear. Both models form an extension of
the orthogonal, by supporting one additional type of edge segments (circular
arcs and diagonal segments, respectively).
For planar graphs of max-degree 4, we analyze relationships between the graph
classes that can be drawn bendless in the two models and we also prove
NP-hardness for a restricted version of the bendless drawing problem for both
models. For planar graphs of higher degree, we present an algorithm that
produces bi-monotone smooth orthogonal drawings with at most two segments per
edge, which also guarantees a linear number of edges with exactly one segment.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
Discrete Convex Functions on Graphs and Their Algorithmic Applications
The present article is an exposition of a theory of discrete convex functions
on certain graph structures, developed by the author in recent years. This
theory is a spin-off of discrete convex analysis by Murota, and is motivated by
combinatorial dualities in multiflow problems and the complexity classification
of facility location problems on graphs. We outline the theory and algorithmic
applications in combinatorial optimization problems
Nodal quasiparticle meltdown in ultra-high resolution pump-probe angle-resolved photoemission
High- cuprate superconductors are characterized by a strong
momentum-dependent anisotropy between the low energy excitations along the
Brillouin zone diagonal (nodal direction) and those along the Brillouin zone
face (antinodal direction). Most obvious is the d-wave superconducting gap,
with the largest magnitude found in the antinodal direction and no gap in the
nodal direction. Additionally, while antinodal quasiparticle excitations appear
only below , superconductivity is thought to be indifferent to nodal
excitations as they are regarded robust and insensitive to . Here we
reveal an unexpected tie between nodal quasiparticles and superconductivity
using high resolution time- and angle-resolved photoemission on optimally doped
BiSrCaCuO. We observe a suppression of the nodal
quasiparticle spectral weight following pump laser excitation and measure its
recovery dynamics. This suppression is dramatically enhanced in the
superconducting state. These results reduce the nodal-antinodal dichotomy and
challenge the conventional view of nodal excitation neutrality in
superconductivity.Comment: 7 pages, 3 figure. To be published in Nature Physic
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