scholarly journals Improved Runtime for the Synchronous Multi-door Filling

2021 ◽  
Author(s):  
Attila Hideg ◽  
Tamás Lukovszki ◽  
Bertalan Forstner
Keyword(s):  
Maximum Degree ◽  
A Priori ◽  
Production Costs ◽  
Running Time ◽  
Previous Algorithm ◽  
Filling Problem

In this paper, a particular type of dispersion is further investigated, which is called Filling. In this problem, robots are injected one by one into an a priori not known area and have to travel across until the whole area is covered. The coverage is achieved by a robotic team whose hardware capabilities are restricted in order to maintain low production costs. This includes limited viewing and communication ranges. In this work, we present an algorithm solving the synchronous Filling problem in O((k + ∆)·n) time steps by n robots with a viewing range of 1 hop, where k is the number of doors, n is the number of vertices of the graph, and ∆ is the maximum degree of the graph. This improves the best previously known running time bound of O(k · ∆ · n). Furthermore, we remove the constraint from the previous algorithm that the door vertices need to have a degree of 1.

scholarly journals LABEL-GUIDED GRAPH EXPLORATION WITH ADJUSTABLE RATIO OF LABELS

2012 ◽  
Vol 23 (04) ◽  
pp. 903-929
Author(s):  
LIANG HU ◽  
MENG ZHANG ◽  
YI ZHANG ◽  
JIJUN TANG
Keyword(s):  
Maximum Degree ◽  
A Priori ◽  
A Priori Knowledge ◽  
Graph Exploration ◽  
Simple Graphs ◽  
System Designer ◽  
Black And White ◽  
Labeling Algorithm ◽  
Multiple Edges ◽  
Labeling Scheme

The graph exploration problem is to visit all the nodes of a connected graph by a mobile entity, e.g., a robot. The robot has no a priori knowledge of the topology of the graph or of its size. Cohen et al. [3] introduced label guided graph exploration which allows the system designer to add short labels to the graph nodes in a preprocessing stage; these labels can guide the robot in the exploration of the graph. In this paper, we address the problem of adjustable 1-bit label guided graph exploration. We focus on the labeling schemes that not only enable a robot to explore the graph but also allow the system designer to adjust the ratio of the number of different labels. This flexibility is necessary when maintaining different labels may have different costs or when the ratio is pre-specified. We present 1-bit labeling (two colors, namely black and white) schemes for this problem along with a labeling algorithm for generating the required labels. Given an n-node graph and a rational number ρ, we can design a 1-bit labeling scheme such that n/b ≥ ρ where b is the number of nodes labeled black. The robot uses O(ρ log Δ) bits of memory for exploring all graphs of maximum degree Δ. The exploration is completed in time [Formula: see text]. Moreover, our labeling scheme can work on graphs containing loops and multiple edges, while that of Cohen et al. focuses on simple graphs.

Charge distribution as a tool to investigate structural details. IV. A new route to heteroligand polyhedra

2016 ◽  
Vol 72 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Massimo Nespolo
Keyword(s):  
Charge Distribution ◽  
A Priori ◽  
Total Charge ◽  
Ionic Radii ◽  
Empirical Parameter ◽  
Coordination Polyhedra ◽  
New Approach ◽  
Bonding Effect ◽  
Structural Details ◽  
Previous Algorithm

A new route to apply the charge distribution (CHARDI) method to structures based on heteroligand coordination polyhedra is presented. The previous algorithm used scale factors computed in an iterative way based on the assumption (which turned out to be not always correct) that a real over–under bonding effect affects mainly the anionic charges of each single anion, without grossly modifying the total charge of each type of anion. The new, more general approach is not based on anya prioriassumption but treats separately the homoligand sub-polyhedra and attributes to each type of atom a fraction of the charge of the atom coordinated to it, computed in a self-consistent iterative way. The distinction between the bonding and non-bonding contact is also redefined in terms of the mean fictive ionic radii (MEFIR), without the need of an empirical parameter, used in the previous algorithm. CHARDI equations are generalized in terms of the new approach and a series of examples is presented.

scholarly journals Deciding Relaxed Two-Colourability: A Hardness Jump

2009 ◽  
Vol 18 (1-2) ◽  
pp. 53-81 ◽  
Author(s):  
R. BERKE ◽  
T. SZABÓ
Keyword(s):  
Decision Problem ◽  
Maximum Degree ◽  
Time Algorithm ◽  
Np Hard ◽  
Running Time ◽  
Symmetric Version ◽  
Component Order ◽  
Colour Classes

We study relaxations of proper two-colourings, such that the order of the induced monochromatic components in one (or both) of the colour classes is bounded by a constant. A colouring of a graph G is called (C1, C2)-relaxed if every monochromatic component induced by vertices of the first (second) colour is of order at most C1 (C2, resp.). We prove that the decision problem ‘Is there a (1, C)-relaxed colouring of a given graph G of maximum degree 3?’ exhibits a hardness jump in the component order C. In other words, there exists an integer f(3) such that the decision problem is NP-hard for every 2 ≤ C < f(3), while every graph of maximum degree 3 is (1, f(3))-relaxed colourable. We also show f(3) ≤ 22 by way of a quasilinear time algorithm, which finds a (1, 22)-relaxed colouring of any graph of maximum degree 3. Both the bound on f(3) and the running time greatly improve earlier results. We also study the symmetric version, that is, when C1 = C2, of the relaxed colouring problem and make the first steps towards establishing a similar hardness jump.

scholarly journals Identification of Technoeconomic Opportunities with the Use of Premium Efficiency Motors as Alternative for Developing Countries

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5411 ◽  
Author(s):  
Julio R. Gómez ◽  
Enrique C. Quispe ◽  
Rosaura del Pilar Castrillón ◽  
Percy R. Viego
Keyword(s):  
Electric Motor ◽  
A Priori ◽  
Industrial Sector ◽  
Production Costs ◽  
Production Cycle ◽  
Final Decision ◽  
Discounted Cash Flow ◽  
Energy Saving Potential ◽  
Cost Of Energy ◽  
The Cost

More than 65% of electricity consumed worldwide by the industrial sector is used in electric-motor-driven systems. For this reason, the efficiency of electric motors is an important factor in improving the energy efficiency of the industry. Additionally, this contributes to reducing energy consumption, production costs, as well as CO2eq emissions. The replacement of motors with efficiency class IE1 by motors of efficiency class IE3 is one possible alternative to increase the efficiency of electric motor systems. When a program to replace motors with others of greater efficiency is initiated, it is necessary to casuistically evaluate all identified opportunities. Economic viability can be evaluated using a variety of methods. Often, the methods recommended by manufacturers or consulting entities focus on simple payback time without accounting for all influencing factors. This paper contributes to the academic discussion by proposing a methodology based on the calculation of energy-saving potential, by performing a preliminary an a priori evaluation and determining the economic opportunities. It avoids evaluating all motors in the studied facility and shows its effectiveness by using the cost of energy saved to distinguish which motors to evaluate. Finally, it provides a complete economic evaluation of the final decision on the basis of discounted cash flow methods. A short-production-cycle sugarcane industry was used in the case study.

scholarly journals Testing Expansion in Bounded-Degree Graphs

2010 ◽  
Vol 19 (5-6) ◽  
pp. 693-709 ◽  
Author(s):  
ARTUR CZUMAJ ◽  
CHRISTIAN SOHLER
Keyword(s):  
Maximum Degree ◽  
Property Testing ◽  
Graph Representation ◽  
Bounded Degree ◽  
Running Time ◽  
Adjacency List ◽  
Bounded Degree Graphs ◽  
Testing Algorithm

We consider the problem of testing expansion in bounded-degree graphs. We focus on the notion of vertex expansion: an α-expander is a graph G = (V, E) in which every subset U ⊆ V of at most |V|/2 vertices has a neighbourhood of size at least α ⋅ |U|. Our main result is that one can distinguish good expanders from graphs that are far from being weak expanders in time $\widetilde{\O}(\sqrt{n})$. We prove that the property-testing algorithm proposed by Goldreich and Ron with appropriately set parameters accepts every α-expander with probability at least $\frac23$ and rejects every graph that is ϵ-far from any α*-expander with probability at least $\frac23$, where $\expand^* \,{=}\, \Theta(\frac{\expand^2}{d^2 \log(n/\epsilon)})$ and d is the maximum degree of the graphs. The algorithm assumes the bounded-degree graphs model with adjacency list graph representation and its running time is $\O(\frac{d^2 \sqrt{n} \log(n/\epsilon)} {\expand^2 \epsilon^3})$.

scholarly journals Multicriteria model of the process of crushing rock

2019 ◽  
Vol 80 (4) ◽  
pp. 111-115
Author(s):  
Yu. V. Bugaev ◽  
L. A. Korobova ◽  
I. S. Tolstova ◽  
Yu. A. Demina
Keyword(s):  
Internal Combustion Engines ◽  
A Priori ◽  
Quality Criteria ◽  
Point Of View ◽  
Production Costs ◽  
Model Quality ◽  
Main Equipment ◽  
Active Experiment ◽  
Energy Consuming ◽  
The Cost

The article deals with the modernization and adjustment of the fine chalk grinding process. The crushing process is an energy-consuming procedure, annually spent about 5% of all energy produced on Earth, including the energy of internal combustion engines. This indicates its great importance. In addition to the cost of electricity, large expenses go to repair the equipment. The greatest replacements are made on the main working parts of machines. In the course of substitutions a lot of time is spent, in order not to spend this rather important resource, it is necessary to approach this procedure from a scientific point of view. The organization and conduct of research on the replacement of the main working parts of crushers and mills will increase the productivity of the main equipment, improve the quality of the finished product and reduce production costs in terms of energy saving. Modernization and adjustment of technological equipment in order to improve the production process of fine chalk significantly increase the service life of the main equipment. For this purpose, it is proposed to conduct an active experiment. Before carrying out the experiment, it is necessary to set the model. The classical regression analysis is based on the assumption that the model type is a priori specified with accuracy to the parameters, and that an experiment has already been implemented that supplies the initial data for the regression construction. Hence, the problem is to choose the best method of data processing. In this paper, we propose a fundamentally new approach-automatic evaluation of the model options on a set of indicators, the calculation of which is based on a set of pareto-optimal variants of the model.The proposed method made it possible to identify two best alternatives out of 16384. Obviously, this approach can be easily modified for any other set of regression model quality criteria.

Catalog-Based Customization

1999 ◽  
Author(s):  
Bala Chidambaram ◽  
Alice M. Agogino
Keyword(s):  
Cost Function ◽  
Cost Estimation ◽  
A Priori ◽  
Production Costs ◽  
Estimation Methods ◽  
Optimization Formulation ◽  
Catalog Design ◽  
Standard Designs ◽  
Approximate Cost ◽  
The Cost

Abstract This paper develops a new method for implementing mass-customization, namely, the customization around standard products, or catalog-based customization. The method addresses the customization requirements of a class of products that are complex in configuration, multi-functional and structurally similar. We formulate catalog-based customization as an optimization problem consistent with the manufacturer’s goal of incurring minimal costs in the redesign of existing standard components, while meeting customer specifications and satisfying design constraints. The ‘catalog-based’ nature of the formulation raises concomitant issues of cost function development and problem simplification/solution. We identify the generational structure as best suited to exploit the cost data in existing catalogs and construct a product cost function. The cost-estimation methods used by the generational structure in the construction are identified as weight-based — for modeling the material costs, and methods based on similarity principles and regression analyses — for the production costs. The optimization formulation of catalog-based customization may be simplified by an a priori identification of a standard catalog design as the customization basis. This is accomplished with function costing — a cost-estimation hypothesis that uses product functionality to develop an approximate cost-estimate. The function-costing estimate is also used to abstract features from the standard base design into the optimization formulation. The preferred solution strategy for the optimization formulation is identified as genetic algorithms. We apply the customization method developed to Brushless D.C. Permanent Magnet (BDCPM) motors and obtain optimal minimal cost custom designs (from the standard designs of a BDCPM motor family) for different sets of customer requirements.

Application of cross correlation to HREM images of surfaces

1987 ◽  
Vol 45 ◽  
pp. 754-755
Author(s):  
D. E. Luzzi ◽  
L. D. Marks ◽  
M. I. Buckett
Keyword(s):  
Cross Correlation ◽  
A Priori ◽  
Matrix Material ◽  
Correlation Method ◽  
Accurate Knowledge ◽  
Complex Image ◽  
Fourier Filtering ◽  
The Matrix ◽  
Low Pass ◽  
Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

Towards 1-Ångstrom-resolution STEM

1993 ◽  
Vol 51 ◽  
pp. 996-997
Author(s):  
H.S. von Harrach ◽  
D.E. Jesson ◽  
S.J. Pennycook
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Phase Contrast ◽  
Spherical Aberration ◽  
A Priori ◽  
Dark Field ◽  
Image Resolution ◽  
Objective Lens ◽  
Annular Dark Field ◽  
First Results

Phase contrast TEM has been the leading technique for high resolution imaging of materials for many years, whilst STEM has been the principal method for high-resolution microanalysis. However, it was demonstrated many years ago that low angle dark-field STEM imaging is a priori capable of almost 50% higher point resolution than coherent bright-field imaging (i.e. phase contrast TEM or STEM). This advantage was not exploited until Pennycook developed the high-angle annular dark-field (ADF) technique which can provide an incoherent image showing both high image resolution and atomic number contrast.This paper describes the design and first results of a 300kV field-emission STEM (VG Microscopes HB603U) which has improved ADF STEM image resolution towards the 1 angstrom target. The instrument uses a cold field-emission gun, generating a 300 kV beam of up to 1 μA from an 11-stage accelerator. The beam is focussed on to the specimen by two condensers and a condenser-objective lens with a spherical aberration coefficient of 1.0 mm.

Treating Velopharyngeal Inadequacy Using Bilateral Buccal Flap Revision Palatoplasty

2019 ◽  
Vol 4 (5) ◽  
pp. 878-892
Author(s):  
Joseph A. Napoli ◽  
Linda D. Vallino
Keyword(s):  
Systematic Review ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
A Priori ◽  
Sufficient Evidence ◽  
Obstructive Sleep ◽  
Before And After ◽  
Buccal Flap

Purpose The 2 most commonly used operations to treat velopharyngeal inadequacy (VPI) are superiorly based pharyngeal flap and sphincter pharyngoplasty, both of which may result in hyponasal speech and airway obstruction. The purpose of this article is to (a) describe the bilateral buccal flap revision palatoplasty (BBFRP) as an alternative technique to manage VPI while minimizing these risks and (b) conduct a systematic review of the evidence of BBFRP on speech and other clinical outcomes. A report comparing the speech of a child with hypernasality before and after BBFRP is presented. Method A review of databases was conducted for studies of buccal flaps to treat VPI. Using the principles of a systematic review, the articles were read, and data were abstracted for study characteristics that were developed a priori. With respect to the case report, speech and instrumental data from a child with repaired cleft lip and palate and hypernasal speech were collected and analyzed before and after surgery. Results Eight articles were included in the analysis. The results were positive, and the evidence is in favor of BBFRP in improving velopharyngeal function, while minimizing the risk of hyponasal speech and obstructive sleep apnea. Before surgery, the child's speech was characterized by moderate hypernasality, and after surgery, it was judged to be within normal limits. Conclusion Based on clinical experience and results from the systematic review, there is sufficient evidence that the buccal flap is effective in improving resonance and minimizing obstructive sleep apnea. We recommend BBFRP as another approach in selected patients to manage VPI. Supplemental Material https://doi.org/10.23641/asha.9919352

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