Forecast-Island and Bidding A*-Euclidean Selecting Boustrophedon Coordination Algorithm for Exploration

2021 ◽  
Author(s):  
Zhifeng Yao ◽  
Fengxia Xu ◽  
Chunsong Han
Keyword(s):  
Euclidean Distance ◽  
Simulation Experiment ◽  
Target Point ◽  
Current Position ◽  
A Algorithm ◽  
Simulation Experiments ◽  
Exploration Time ◽  
Long Time ◽  
The Cost ◽  
Walking Time

Exploration algorithms based on the Boustrophedon path seldom consider the impacts of a robot turning at corners on the exploration time. This paper proposes the Forecast-Island and Bidding A*-Euclidean Selecting Boustrophedon Coordination (FIBA*ESBC) algorithm to calculate the turning time at corners in the overall exploration time and introduces a method to estimate the walking time in the Boustrophedon paths in order to determine the directions for path execution. Typically, in bidding-based exploration tasks, the cost is the Euclidean distance between the current position of the robot and the target point. When there is an obstacle between two points, the cost is set to infinity. Therefore, the selected target point is sometimes not optimal. The FIBA*ESBC algorithm is based on the exploration cost of a combination of the Euclidean distance and A* algorithm walking path, which can effectively solve this problem. Because the bidding is based on a greedy algorithm, the robot has a small unexplored island in the later exploration stage; therefore, full exploration is not possible or requires a long time with several repeated paths. The FIBA*ESBC algorithm prioritizes the exploration and estimation of hidden and existing unexplored islands. It can realize complete exploration and decrease the exploration time. Through simulation experiments conducted using Gazebo and RViz, the feasibility of the FIBA*ESBC algorithm is verified. Moreover, a simulation experiment is conducted in MATLAB for comparison with other algorithms. The analysis of the experimental data shows that the proposed algorithm has a relatively short exploration time.

scholarly journals Seawater Absorption and Adhesion Properties of Hydrophobic and Superhydrophobic Thermoset Epoxy Nanocomposite Coatings

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Salt Spray ◽  
Adhesion Properties ◽  
In Situ Modification ◽  
Long Time ◽  
Seawater Environment ◽  
Thermoset Epoxy ◽  
The Cost

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.

Computing Robust Principal Components by A* Search

2018 ◽  
Vol 27 (07) ◽  
pp. 1860013 ◽  
Author(s):  
Swair Shah ◽  
Baokun He ◽  
Crystal Maung ◽  
Haim Schweitzer
Keyword(s):  
State Of The Art ◽  
Principal Component ◽  
Low Rank ◽  
A Algorithm ◽  
Running Time ◽  
Current State ◽  
Dimensionality Reduction Technique ◽  
Related Variant ◽  
Low Rank Representation ◽  
The Cost

Principal Component Analysis (PCA) is a classical dimensionality reduction technique that computes a low rank representation of the data. Recent studies have shown how to compute this low rank representation from most of the data, excluding a small amount of outlier data. We show how to convert this problem into graph search, and describe an algorithm that solves this problem optimally by applying a variant of the A* algorithm to search for the outliers. The results obtained by our algorithm are optimal in terms of accuracy, and are shown to be more accurate than results obtained by the current state-of-the- art algorithms which are shown not to be optimal. This comes at the cost of running time, which is typically slower than the current state of the art. We also describe a related variant of the A* algorithm that runs much faster than the optimal variant and produces a solution that is guaranteed to be near the optimal. This variant is shown experimentally to be more accurate than the current state-of-the-art and has a comparable running time.

Inferring age from otolith measurements: a review and a new approach

2004 ◽  
Vol 61 (7) ◽  
pp. 1269-1284 ◽  
Author(s):  
RIC Chris Francis ◽  
Steven E Campana
Keyword(s):  
Simulation Experiment ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
New Method ◽  
Population Parameters ◽  
Benefit Analysis ◽  
Mixture Analysis ◽  
New Approach ◽  
Individual Fish ◽  
The Cost

In 1985, Boehlert (Fish. Bull. 83: 103–117) suggested that fish age could be estimated from otolith measurements. Since that time, a number of inferential techniques have been proposed and tested in a range of species. A review of these techniques shows that all are subject to at least one of four types of bias. In addition, they all focus on assigning ages to individual fish, whereas the estimation of population parameters (particularly proportions at age) is usually the goal. We propose a new flexible method of inference based on mixture analysis, which avoids these biases and makes better use of the data. We argue that the most appropriate technique for evaluating the performance of these methods is a cost–benefit analysis that compares the cost of the estimated ages with that of the traditional annulus count method. A simulation experiment is used to illustrate both the new method and the cost–benefit analysis.

Wartime activities of the Vavilov Institute

2021 ◽  
Vol 182 (2) ◽  
pp. 151-162
Author(s):  
I. G. Loskutov
Keyword(s):  
Plant Genetic Resources ◽  
Cultivated Plants ◽  
Left Behind ◽  
Long Time ◽  
Potato Collection ◽  
The Government ◽  
The Cost ◽  
The City ◽  
Harsh Reality ◽  
Difficult Part

Among the chronicles relating the heroism of the besieged Leningrad, there are pages dedicated to the deeds performed by the staff the world-famous All-Union Research Institute of Plant Industry (VIR, now the N.I. Vavilov All-Russian Institute of Plant Genetic Resources). With the beginning of the war, even before the city was surrounded by the Nazi troops, the government decided to evacuate a number of factories and institutes from Leningrad, including VIR, but the plan failed. Only in winter did the Institute start partial evacuation, although preparations had been going on for a long time. The largest and most important part of the collection was left behind in the besieged city. The remaining employees were forced to work under the hardest conditions of the siege, in unheated premises. In the harsh reality of the winter in 1941–1942, the daily bread rationing was cut down, and hunger raged in the city, killing tens of thousands of city residents, including VIR employees who kept the stored seeds and tubers untouched. The most difficult part was preserving the potato collection. In the spring of 1942, preparations were made for sowing to restore the viability of seeds and tubers in the fields of Leningrad’s suburban area under the fire from the enemy artillery. Only the heroic efforts of VIR’s staff helped to save the collection from destruction and loss of germination. This heroism cost more than 20 experts and scientists their lives. So, the most dangerous period for the Institute was overcome at such price. Immediately after the siege was lifted, a group of experts was sent to Leningrad from Krasnoufimsk to help with selecting seed accessions for urgent reproduction. Working under extreme physical exhaustion in frozen premises, without water or electricity, under continuous shelling, they saved, many at the cost of their own lives, the collection of cultivated plants and their wild relatives, the herbarium, and the scientific library for future generations. 

scholarly journals Complex Event Processing for Sensor Stream Data

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3084 ◽  
Author(s):  
Kyoungsoo Bok ◽  
Daeyun Kim ◽  
Jaesoo Yoo
Keyword(s):  
Real Time ◽  
Complex Event Processing ◽  
Superior Performance ◽  
Event Processing ◽  
Stream Data ◽  
Internet Of Things Environment ◽  
Processing Cost ◽  
Single Operator ◽  
Long Time ◽  
The Cost

As a large amount of stream data are generated through sensors over the Internet of Things environment, studies on complex event processing have been conducted to detect information required by users or specific applications in real time. A complex event is made by combining primitive events through a number of operators. However, the existing complex event-processing methods take a long time because they do not consider similarity and redundancy of operators. In this paper, we propose a new complex event-processing method considering similar and redundant operations for stream data from sensors in real time. In the proposed method, a similar operation in common events is converted into a virtual operator, and redundant operations on the same events are converted into a single operator. The event query tree for complex event detection is reconstructed using the converted operators. Through this method, the cost of comparison and inspection of similar and redundant operations is reduced, thereby decreasing the overall processing cost. To prove the superior performance of the proposed method, its performance is evaluated in comparison with existing methods.

scholarly journals Borehole Rehabilitation: A Case Study in the Dunkwa Mining Town

2020 ◽  
Vol 20 (2) ◽  
pp. 11-17
Author(s):  
A. Ewusi ◽  
J. Seidu
Keyword(s):  
Water Supply ◽  
Central Region ◽  
Pumping Test ◽  
Implementation Cost ◽  
Mining Town ◽  
Long Time ◽  
Borehole Camera ◽  
The Cost ◽  
Very High

Rehabilitation works were carried out on boreholes in the Dunkwa Mining town in the Central Region of Ghana. These works were carried out because the boreholes had lost their original yields due to clogging, corrosion and encrustation and had been abandoned for a long time. The cost of drilling a new well and assessing the productivity of the well is $4,500 which is more expensive that carrying out rehabilitation works which is cheaper, about $800. Also, the initial yields of the boreholes were very high according to the feasibility report which is not a common characteristic of the rocks in the area. Camera inspection followed by rehabilitation, pre and post pumping tests were carried out to assess whether there has been an improvement in their yield after the exercise and that the yield obtained will be adequate for a water supply design. Results show that all the boreholes had an improvement in their yields (57.19 - 259.80 %) after the rehabilitation. It can therefore be concluded that rehabilitation is effective in restoring boreholes to their original yields. Organisations drilling boreholes to communities can take advantage of rehabilitation of the existing boreholes located in the communities which are high yielding, thereby reducing project implementation cost. Keywords: Borehole Rehabilitation, Borehole Yields, Borehole Camera Inspection, Pumping Test

scholarly journals COMPARATIVE ANALYSIS AND SELECTION OF TECHNOLOGY OF DEVICE OF FENCING METAL STRUCTURES IN CONSTRUCTION OF UNDERGROUND STRUCTURES

2021 ◽  
Vol 9 (1) ◽  
pp. 26-30
Author(s):  
Elena Korol ◽  
Zarina Chipova
Keyword(s):  
Underground Structures ◽  
Engineering Structures ◽  
Metal Structures ◽  
Large Cities ◽  
Long Time ◽  
Complex Engineering ◽  
Transport Problems ◽  
The Cost ◽  
Transport Complex ◽  
Selection Of

Urban motor transport complex engineering structures, the construction of which is carried out for a long time, and the cost is often tunnels of structures. Despite this, urban tunnels remain in demand as a means of solving transport problems, especially for large cities, in areas with dense urban development or an established architectural appearance, the violation of which is unacceptable. The construction of tunnels makes it possible to increase the throughput of highways, especially in places of large intersections, one of the diverting high-intensity transit traffic flows underground, making them invisible on the surface and thus not disrupting the existing historical appearance of the area.

scholarly journals Solving the inverse heat conduction problem using NVLink capable Power architecture

2017 ◽  
Vol 3 ◽  
pp. e138 ◽  
Author(s):  
Sándor Szénási
Keyword(s):  
Heat Transfer ◽  
Data Transfer ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inverse Heat Transfer ◽  
Long Time ◽  
History Of ◽  
The Cost

The accurate knowledge of Heat Transfer Coefficients is essential for the design of precise heat transfer operations. The determination of these values requires Inverse Heat Transfer Calculations, which are usually based on heuristic optimisation techniques, like Genetic Algorithms or Particle Swarm Optimisation. The main bottleneck of these heuristics is the high computational demand of the cost function calculation, which is usually based on heat transfer simulations producing the thermal history of the workpiece at given locations. This Direct Heat Transfer Calculation is a well parallelisable process, making it feasible to implement an efficient GPU kernel for this purpose. This paper presents a novel step forward: based on the special requirements of the heuristics solving the inverse problem (executing hundreds of simulations in a parallel fashion at the end of each iteration), it is possible to gain a higher level of parallelism using multiple graphics accelerators. The results show that this implementation (running on 4 GPUs) is about 120 times faster than a traditional CPU implementation using 20 cores. The latest developments of the GPU-based High Power Computations area were also analysed, like the new NVLink connection between the host and the devices, which tries to solve the long time existing data transfer handicap of GPU programming.

scholarly journals The simulation experiment description markup language (SED-ML): language specification for level 1 version 4

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lucian P. Smith ◽  
Frank T. Bergmann ◽  
Alan Garny ◽  
Tomáš Helikar ◽  
Jonathan Karr ◽  
...  
Keyword(s):  
Simulation Experiment ◽  
Computational Simulation ◽  
Spatial Models ◽  
Software Tools ◽  
Stochastic Simulations ◽  
Biological Research ◽  
Simulation Experiments ◽  
Additional Information ◽  
Parameter Estimations ◽  
Level 1

Abstract Computational simulation experiments increasingly inform modern biological research, and bring with them the need to provide ways to annotate, archive, share and reproduce the experiments performed. These simulations increasingly require extensive collaboration among modelers, experimentalists, and engineers. The Minimum Information About a Simulation Experiment (MIASE) guidelines outline the information needed to share simulation experiments. SED-ML is a computer-readable format for the information outlined by MIASE, created as a community project and supported by many investigators and software tools. The first versions of SED-ML focused on deterministic and stochastic simulations of models. Level 1 Version 4 of SED-ML substantially expands these capabilities to cover additional types of models, model languages, parameter estimations, simulations and analyses of models, and analyses and visualizations of simulation results. To facilitate consistent practices across the community, Level 1 Version 4 also more clearly describes the use of SED-ML constructs, and includes numerous concrete validation rules. SED-ML is supported by a growing ecosystem of investigators, model languages, and software tools, including eight languages for constraint-based, kinetic, qualitative, rule-based, and spatial models, over 20 simulation tools, visual editors, model repositories, and validators. Additional information about SED-ML is available at https://sed-ml.org/.

The Design of Virtual Experiment Framework Based on ELVIS

2014 ◽  
Vol 1037 ◽  
pp. 161-164
Author(s):  
Dong Dong Li
Keyword(s):  
Simulation Experiment ◽  
Teaching Method ◽  
Standard Test ◽  
Virtual Experiment ◽  
Traditional Teaching ◽  
Virtual Instrumentation ◽  
Virtual Experiments ◽  
Function Modules ◽  
Innovation Ability ◽  
The Cost

The virtual simulation experiment framework consists of hardware and software function modules, which are both designed in this thesis. The application of virtual experiment framework has changed the traditional teaching method to a large extent, reduced the cost of laboratory construction and management, which is of the first importance to realize the remote experiment teaching. Through virtual experiments, students' interest in knowledge is cultivated and innovation ability is enhanced. With the National Instruments Educational Laboratory Virtual Instrumentation Suite (NI ELVIS) and LabVIEW, we could take advantage of graphical programming and a complete suite of standard test instruments on computer and directly interface these instruments to circuits, which is the base of virtual experiment framework.

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