scholarly journals On multiple coverings of the infinite rectangular grid with balls of constant radius

2003 ◽  
Vol 268 (1-3) ◽  
pp. 31-48 ◽  
Author(s):  
Maria A. Axenovich
1999 ◽  
Vol 558 ◽  
Author(s):  
J. Martins ◽  
M. Fernandes ◽  
F. Sousa ◽  
P. Louro ◽  
A. MaçArico ◽  
...  

ABSTRACTA TCO/ μc-p-i-n Si:H/AI imager is presented and analyzed. The μc-p-i-n Si:H photodiode acts as a sensing element. Contacts are used as an electrical interface. The image is acquired by a scan-out process. Sampling is performed on a rectangular grid, and the read-out of the photogenerated charges is achieved by measuring simultaneously both transverse photovoltages at the coplanar electrodes. The image representation in gray-tones is obtained by using low level processing algorithms. Basic image processing algorithms are developed for image enhancement and restoration.


2011 ◽  
Vol 58-60 ◽  
pp. 1860-1865 ◽  
Author(s):  
Samuel Lukas ◽  
Arnold Aribowo ◽  
Steven Christian Halim

Shikaku is a logic puzzle published by Nikoli at 2005. Shikaku has a very simple rule. This puzzle is played on a rectangular grid. Some of the squares in the grid are numbered. The main objective is to create partitions inside the grid. Each partition must have exactly one number, and the number represents the area of the partition. Then the partition’s shape must be a rectangular or a square. The aim of this research is discussing how can computer software be able to solve the Shikaku problem by implementing heuristic technique and genetics algorithms. Initially the Shikaku problem is inputted into the system. Firstly, the software will solve the problem by applying heuristics methods with some logic rules. All logic rules are created and implemented into the software so that the software can minimize the partitions possibilities to the problem. If this heuristics method still can not solve the problem then genetic algorithms will be executed to find the solution. This paper elaborates from how the problem be modelled and also be implemented until software testing to ensure that the solver worked as expected. The implementation consists of a virtual puzzle board with three different size, genetic algorithms parameters, and ability to create, save, load, and solve puzzle. Software testing is conducted to find how fast the system can solve the problem.


2012 ◽  
Vol 160 (3) ◽  
pp. 210-217 ◽  
Author(s):  
Fatemeh Keshavarz-Kohjerdi ◽  
Alireza Bagheri ◽  
Asghar Asgharian-Sardroud

2020 ◽  
Author(s):  
Masatsugu Nishimura ◽  
Yoshitaka Tezuka ◽  
Enrico Picotti ◽  
Mattia Bruschetta ◽  
Francesco Ambrogi ◽  
...  

Various rider models have been proposed that provide control inputs for the simulation of motorcycle dynamics. However, those models are mostly used to simulate production motorcycles, so they assume that all motions are in the linear region such as those in a constant radius turn. As such, their performance is insufficient for simulating racing motorcycles that experience quick acceleration and braking. Therefore, this study proposes a new rider model for racing simulation that incorporates Nonlinear Model Predictive Control. In developing this model, it was built on the premise that it can cope with running conditions that lose contact with the front wheels or rear wheels so-called "endo" and "wheelie", which often occur during running with large acceleration or deceleration assuming a race. For the control inputs to the vehicle, we incorporated the lateral shift of the rider's center of gravity in addition to the normally used inputs such as the steering angle, throttle position, and braking force. We compared the performance of the new model with that of the conventional model under constant radius cornering and straight braking, as well as complex braking and acceleration in a single (hairpin) corner that represented a racing run. The results showed that the new rider model outperformed the conventional model, especially in the wider range of running speed usable for a simulation. In addition, we compared the simulation results for complex braking and acceleration in a single hairpin corner produced by the new model with data from an actual race and verified that the new model was able to accurately simulate the run of actual MotoGP riders.


Author(s):  
A. Alberdi ◽  
M. Marin ◽  
I. Etxeberria ◽  
G. Alberdi

Combined techniques of Physical Vapour Deposition (PVD), laser ablation and UV-Photolithography have been set up to produce well defined surface textures able to increase the seizure resistance of high loaded lubricated systems. Using these new techniques, different predefined surface textures, following rectangular grid and zigzag stripped patterns have been generated. The microstructured surfaces developed have been characterised with confocal microscopy, optical and scanning electron microscopy. Ball-on-disc tribological tests under progressively increased load have been carried out using mineral oil as lubricant to determine the influence of surface microtextures on seizure resistance. The influence of shape and size of texture patterns on the tribological performance of the surface have been also studied.


10.37236/160 ◽  
2009 ◽  
Vol 16 (1) ◽  
Author(s):  
Daniel Král' ◽  
Douglas B. West

Let ${\cal G}$ be a class of graphs. A $d$-fold grid over ${\cal G}$ is a graph obtained from a $d$-dimensional rectangular grid of vertices by placing a graph from ${\cal G}$ on each of the lines parallel to one of the axes. Thus each vertex belongs to $d$ of these subgraphs. The class of $d$-fold grids over ${\cal G}$ is denoted by ${\cal G}^d$. Let $f({\cal G};d)=\max_{G\in{\cal G}^d}\chi(G)$. If each graph in ${\cal G}$ is $k$-colorable, then $f({\cal G};d)\le k^d$. We show that this bound is best possible by proving that $f({\cal G};d)=k^d$ when ${\cal G}$ is the class of all $k$-colorable graphs. We also show that $f({\cal G};d)\ge{\left\lfloor\sqrt{{d\over 6\log d}}\right\rfloor}$ when ${\cal G}$ is the class of graphs with at most one edge, and $f({\cal G};d)\ge {\left\lfloor{d\over 6\log d}\right\rfloor}$ when ${\cal G}$ is the class of graphs with maximum degree $1$.


2019 ◽  
Vol 11 (4) ◽  
pp. 93-106
Author(s):  
Carlos GONZAGA-LOPEZ ◽  
Florian Michael BUCHMANN ◽  
Henrik EKSTRAND ◽  
Andreas LINNÉR ◽  
Philipp Daniel SCHAAD

The results of a preliminary study on the emulation of radius-to-fix legs in turning departures by means of standard track-to-fix legs are presented in this technical note. While radius-to-fix equipage rates keep gradually increasing over time, a traffic mix containing aircraft with and without this navigation capability can impede an optimal management of the traffic flows whenever precise and repeatable curved flight paths are required. After test-flying various sequences of track-to-fix segments to emulate a reference constant-radius arc in a typical departure environment, the deviations to the desired flight path and the flyability aspects were assessed. The first results for a given scenario and aircraft type show an adequate path conformance for a navigation specification RNAV/RNP 1 within a certain range of aircraft performances and weather conditions. However, the reduced predictability of the roll steering when transitioning between track-to-fix segments and the high frequency in the oscillations of the bank angle may pose a problem to flight crews and passengers, respectively.


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