Automatic Lawn Mower using Green Energy Sources

An automatic lawn mower is a device or robot that help human to cut grass automatically. It will allow the user to cut their grass with minimal effort. The proposed robotmove on the grass of the garden, within a defined area thereby completes the task automatically. The electrical power required to energies the proposed system is provided from the solar panel. Single-Ended Primary-Inductor Converter (SEPIC)with Maximum Power Point Tracking (MPPT) algorithm and Fuzzy logic controller (FLC) is used at output of solar panel to improve the overall efficiency. The movement or the path of the automatic lawn mower is based on a path planning technique. Sensors are used to provide feedback from obstacles. Every action of the lawn mower is monitored by the PIC microcontroller with the help of the sensor. Unlike other robotic lawn mowers on the market, this design requires no perimeter wires to maintain the robot within the lawn. Through sensor arrangement, the proposed lawn mower avoidsobstacles and humans. A hardware prototype is implemented and successfully tested in the lawn

Distance and the pattern of intra-European trade

Given an undirected graph G = (V, E) and subset of terminals T ⊆ V, the element-connectivity κ ′ G (u, v) of two terminals u, v ∈ T is the maximum number of u-v paths that are pairwise disjoint in both edges and non-terminals V \ T (the paths need not be disjoint in terminals). Element-connectivity is more general than edge-connectivity and less general than vertex-connectivity. Hind and Oellermann [21] gave a graph reduction step that preserves the global element-connectivity of the graph. We show that this step also preserves local connectivity, that is, all the pairwise element-connectivities of the terminals. We give two applications of this reduction step to connectivity and network design problems. • Given a graph G and disjoint terminal sets T1, T2,..., Tm, we seek a maximum number of elementdisjoint Steiner forests where each forest connects each Ti. We prove that if each Ti is k element k connected then there exist Ω( log hlog m) element-disjoint Steiner forests, where h = | i Ti|. If G is planar (or more generally, has fixed genus), we show that there exist Ω(k) Steiner forests. Our proofs are constructive, giving poly-time algorithms to find these forests; these are the first non-trivial algorithms for packing element-disjoint Steiner Forests. • We give a very short and intuitive proof of a spider-decomposition theorem of Chuzhoy and Khanna [12] in the context of the single-sink k-vertex-connectivity problem; this yields a simple and alternative analysis of an O(k log n) approximation. Our results highlight the effectiveness of the element-connectivity reduction step; we believe it will find more applications in the future

Algorithms for dense graphs and networks

We improve upon the running time of several graph and network algorithms when applied to dense graphs. In particular, we show how to compute on a machine with word size $\lambda$ a maximal matching in an $n$--vertex bipartite graph in time $O(n^{2} + n^{2.5}/\lambda) = 0(n^{2.5}/\log n)$, how to compute the transitive closure of a digraph with $n$ vertices and $m$ edges in time $0(nm/\lambda)$, how to solve the uncapacitated transportation problem with integer costs in the range $[0..C]$ and integer demands in the range $[-U..U]$ in time $0((n^3(\log\log n/\log n)^{1/2} + n^2 \log U)\log nC)$, and how to solve the assignment problem with integer costs in the range $[0..C]$ in time $0(n^{2.5}\log nC/(\log n/\log \log n)^{1/4})$. \\ Assuming a suitably compressed input, we also show how to do depth--first and breadth--first search and how to compute strongly connected components and biconnected components in time $0(n\lambda + n^2/\lambda)$, and how to solve the single source shortest path problem with integer costs in the range $[0..C]$ in time $0(n^2(\log C)/\log n)$

The role of epoxyeicosatrienoic acids in the cardiovascular system.

There is increasing evidence suggesting that epoxyeicosatrienoic acids (EETs) play an important role in cardioprotective mechanisms. These include regulating vascular tone, modulating inflammatory responses, improving cardiomyocyte function and reducing ischaemic damage, resulting in attenuation of animal models of cardiovascular risk factors. This review discusses the current knowledge on the role of EETs in endothelium-dependent control of vascular tone in the healthy and in subjects with cardiovascular risk factors, and considers the pharmacological potential of targeting this pathway.Dr. Lucy Yang is funded by the Wellcome Trust TMAT programme, the Sackler fellowship, and Clare College Research Expenses Fund. Professor Ian Wilkinson and Dr. Joseph Cheriyan are both funded by the Cambridge Biomedical Research Centre. Professor Ian Wilkinson and Dr. Carmel McEniery are both funded by the British Heart Foundation.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/bcp.1260

Increased Incidence of Interatrial Block in Younger Adults with Cryptogenic Stroke and Patent Foramen Ovale

Background: Stroke is often unexplained in younger adults, although it is often associated with a patent foramen ovale (PFO). The reason for the association is not fully explained, and mechanisms other than paradoxical embolism may be involved. Young stroke patients with PFO have more atrial vulnerability than those without PFO. It is plausible that stretching of the interatrial septum may disrupt the interatrial conduction pathways causing interatrial block (IAB). IAB is associated with atrial fibrillation, dysfunctional left atria and stroke. Methods: Electrocardiogram (ECG) characteristics of prospectively recruited young patients (≤55 years of age) with unexplained stroke (TOAST and A-S-C-O) were compared with control data. All stroke cases underwent bubble contrast transthoracic and transoesophageal echography. IAB was defined as a P-wave duration of ≧110 ms. ECG data were converted to electronic format and analysed in a blind manner. Results: Fifty-five patients and 23 datasets were analysed. Patients with unexplained stroke had longer P-wave duration (p = 0.013) and a greater prevalence of IAB (p = 0.02) than healthy controls. Case status was an independent predictor of P-wave duration in a significant multivariate model. There was a significant increase in the proportion of cases with a PFO with IAB compared with cases without PFO and with controls (p = 0.005). Conclusions: Young patients with unexplained stroke, particularly those with PFO, exhibit abnormal atrial electrical characteristics suggesting atrial arrhythmia or atrial dysfunction as a possible mechanism of stroke

Approximability of Connected Factors

Finding a d-regular spanning subgraph (or d-factor) of a graph is easy by Tutte's reduction to the matching problem. By the same reduction, it is easy to find a minimal or maximal d-factor of a graph. However, if we require that the d-factor is connected, these problems become NP-hard - finding a minimal connected 2-factor is just the traveling salesman problem (TSP). Given a complete graph with edge weights that satisfy the triangle inequality, we consider the problem of finding a minimal connected $d$-factor. We give a 3-approximation for all $d$ and improve this to an (r+1)-approximation for even d, where r is the approximation ratio of the TSP. This yields a 2.5-approximation for even d. The same algorithm yields an (r+1)-approximation for the directed version of the problem, where r is the approximation ratio of the asymmetric TSP. We also show that none of these minimization problems can be approximated better than the corresponding TSP. Finally, for the decision problem of deciding whether a given graph contains a connected d-factor, we extend known hardness results.Comment: To appear in the proceedings of WAOA 201