scholarly journals On Computing the Degree of Convexity of Polyominoes

10.37236/3678 ◽  
2015 ◽  
Vol 22 (1) ◽  
Author(s):  
Stefano Brocchi ◽  
Giuseppa Castiglione ◽  
Paolo Massazza
Keyword(s):  

In this paper we present an algorithm which has as input a convex polyomino $P$ and computes its degree of convexity, defined as the smallest integer $k$ such that any two cells of $P$ can be joined by a monotone path inside $P$ with at most $k$ changes of direction. The algorithm uses space $O(m + n)$ to represent a polyomino $P$ with $n$ rows and $m$ columns, and has a running time $O(min(m; r k))$, where $r$ is the number of corners of $P$. Moreover, the algorithm leads naturally to a decomposition of $P$ into simpler polyominoes.

Author(s):  
Jangbae Jeon

Abstract This work presents a novel method of continuous improvement for faster, better and cheaper TEM sample preparation using Cut Look and Measure (CLM). The improvement of the process is executed by operational monitoring of daily beam conditions, end products, bulk thickness control, recipe usage and tool running time. This process produces a consequent decrease in rework rate and process time. In addition, it also increases throughput with better quality TEM samples.


Author(s):  
Jeffrey L. Adler

For a wide range of transportation network path search problems, the A* heuristic significantly reduces both search effort and running time when compared to basic label-setting algorithms. The motivation for this research was to determine if additional savings could be attained by further experimenting with refinements to the A* approach. We propose a best neighbor heuristic improvement to the A* algorithm that yields additional benefits by significantly reducing the search effort on sparse networks. The level of reduction in running time improves as the average outdegree of the network decreases and the number of paths sought increases.


2018 ◽  
Vol 1 (3) ◽  
pp. 2
Author(s):  
José Stênio De Negreiros Júnior ◽  
Daniel Do Nascimento e Sá Cavalcante ◽  
Jermana Lopes de Moraes ◽  
Lucas Rodrigues Marcelino ◽  
Francisco Tadeu De Carvalho Belchior Magalhães ◽  
...  

Simulating the propagation of optical pulses in a single mode optical fiber is of fundamental importance for studying the several effects that may occur within such medium when it is under some linear and nonlinear effects. In this work, we simulate it by implementing the nonlinear Schrödinger equation using the Split-Step Fourier method in some of its approaches. Then, we compare their running time, algorithm complexity and accuracy regarding energy conservation of the optical pulse. We note that the method is simple to implement and presents good results of energy conservation, besides low temporal cost. We observe a greater precision for the symmetrized approach, although its running time can be up to 126% higher than the other approaches, depending on the parameters set. We conclude that the time window must be adjusted for each length of propagation in the fiber, so that the error regarding energy conservation during propagation can be reduced.


2021 ◽  
Vol 15 (6) ◽  
pp. 1-27
Author(s):  
Marco Bressan ◽  
Stefano Leucci ◽  
Alessandro Panconesi

We address the problem of computing the distribution of induced connected subgraphs, aka graphlets or motifs , in large graphs. The current state-of-the-art algorithms estimate the motif counts via uniform sampling by leveraging the color coding technique by Alon, Yuster, and Zwick. In this work, we extend the applicability of this approach by introducing a set of algorithmic optimizations and techniques that reduce the running time and space usage of color coding and improve the accuracy of the counts. To this end, we first show how to optimize color coding to efficiently build a compact table of a representative subsample of all graphlets in the input graph. For 8-node motifs, we can build such a table in one hour for a graph with 65M nodes and 1.8B edges, which is times larger than the state of the art. We then introduce a novel adaptive sampling scheme that breaks the “additive error barrier” of uniform sampling, guaranteeing multiplicative approximations instead of just additive ones. This allows us to count not only the most frequent motifs, but also extremely rare ones. For instance, on one graph we accurately count nearly 10.000 distinct 8-node motifs whose relative frequency is so small that uniform sampling would literally take centuries to find them. Our results show that color coding is still the most promising approach to scalable motif counting.


Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1306
Author(s):  
Elsayed Badr ◽  
Sultan Almotairi ◽  
Abdallah El Ghamry

In this paper, we propose a novel blended algorithm that has the advantages of the trisection method and the false position method. Numerical results indicate that the proposed algorithm outperforms the secant, the trisection, the Newton–Raphson, the bisection and the regula falsi methods, as well as the hybrid of the last two methods proposed by Sabharwal, with regard to the number of iterations and the average running time.


2021 ◽  
Vol 13 (13) ◽  
pp. 7359
Author(s):  
Sadaf Alam ◽  
Miimu Airaksinen ◽  
Risto Lahdelma

Key stakeholders in industry are highly responsible for achieving energy performance targets. Particularly, this paper assesses the attitudes, approaches, and experiences of Finnish construction professionals regarding energy-efficient buildings, or nZEBs. A three-tier investigation was conducted including surveys and expert interviews with several stakeholders. The structure of this approach was informed by preliminary data and information available on the Finnish construction sector. The questionnaire showed that the stakeholders ranked energy efficiency and embodied energy/carbon as very important. The survey highlighted that the importance of the embodied carbon CO2 in the materials is less important than the energy efficiency from many of the stakeholders’ points of view. “Energy efficiency” is very important for ESCOs, contractors, and facility managers followed by architects, HVAC engineers, and construction design engineers. Nevertheless, the opinions of architects ranked “embodied energy CO2” as the most important regarding nZEB. When it comes to the importance of “running time emissions” toward nZEB, contractors and ESCO companies ranked it as 1 for importance followed by property owners (78%) and tenants (75%). It is very fascinating to see from the survey that “running time carbon emissions” has been ranked 1 (very important) by all stakeholders. This study will enable construction industry stakeholders to make provisions for overcoming the barriers, gaps, and challenges identified in the practices of the nZEB projects. It will also inform the formulation of policies that drive retrofit uptake.


Sign in / Sign up

Export Citation Format

Share Document