Equitable persistent coverage of non-convex environments with graph-based planning

2019 ◽  
Vol 38 (14) ◽  
pp. 1674-1694
Author(s):  
José Manuel Palacios-Gasós ◽  
Danilo Tardioli ◽  
Eduardo Montijano ◽  
Carlos Sagüés

In this article, we tackle the problem of persistently covering a complex non-convex environment with a team of robots. We consider scenarios where the coverage quality of the environment deteriorates with time, requiring every point to be constantly revisited. As a first step, our solution finds a partition of the environment where the amount of work for each robot, weighted by the importance of each point, is equal. This is achieved using a power diagram and finding an equitable partition through a provably correct distributed control law on the power weights. Compared with other existing partitioning methods, our solution considers a continuous environment formulation with non-convex obstacles. In the second step, each robot computes a graph that gathers sweep-like paths and covers its entire partition. At each planning time, the coverage error at the graph vertices is assigned as weights of the corresponding edges. Then, our solution is capable of efficiently finding the optimal open coverage path through the graph with respect to the coverage error per distance traversed. Simulation and experimental results are presented to support our proposal.

1987 ◽  
Vol 31 (3) ◽  
pp. 350-352
Author(s):  
Stephen C. Merriman

This paper describes the application of affordable program management software to the task of planning human factors programs conducted in support of complex system developments. A model of the military system acquisition process was developed and a model human factors engineering program was overlayed upon it. Interdependencies were created between the models so that changes made in the acquisition schedule would cause the human factors program to be automatically tailored. This approach has potential to reduce planning time and increase the quality of human factors plans.


2020 ◽  
Vol 10 (1) ◽  
pp. 12
Author(s):  
ROSIHAN ROSMAN ◽  
SRI SETYATI HARJADI ◽  
SUGENG SUDIATSO ◽  
SUDIRMAN YAHYA ◽  
BAMBANG SAPTA PURWOKO ◽  
...  

<p>Penelitian yang betujuan mcngkaji pengaruh periode pcncahayaan terhadap petumbuhan, hasil dan komponen minyak tanaman M. piperita L, telah dilakukan di Instalasi Penelitian Balai Penelitian Tanaman Rempah dan Obat, Lembang, Jawa Barat, dai bulan Januari 2000 hingga Juli 2000. Penelitian dilakukan dua tahap. Tahap pertama membuat variasi lingkungan cahaya dan tahap kedua penyulingan dan analisis komponen minyak dengan kromatograi gas spektrometer massa. Penelitian menggunakan rancangan acak kelompok 5 perlakuan, yaitu I^&gt; (panjang hari normal sebagai kontrol), L, (pemutusan periode gelap 1 jam, pukul 21.00-22.00 mulai umur 30 hari), Lj (pemutusan peiode gelap 1 jam, pukul 21.00-22.00 mulai umur 60 hai), Lj (penambahan cahaya 4 jam, pukul 18.00-22.00 mulai umur 30 hai), dan U (penambahan cahaya 4 jam, pukul 18.00-22.00 mulai umur 60 hari). Hasil penelitian menunjuk¬ kan bahwa perubahan lingkungan mengubah fcnologi tanaman M. piperita L, meliputi petumbuhan vegetatif dan reproduktif, yang selanjutnya mempengaruhi sintesis menthol. Penambahan cahaya 4 jam mulai umur 30 hari setelah tanam (Li) memberikan petumbuhan vegetatif dan reproduktif paling baik, dengan ciri-ciri morfologi tanaman sebagai berikut tanaman berbunga, batang tegak (tidak rebah), tanaman tinggi, diameter batang besar, jumlah ruas banyak, stolon sedikit, jumlah daun banyak dan lebar. Fcnologi tanaman yang mcmiliki petumbuhan vegetatif dan reproduktif yang baik dapat menghasilkan produksi tema dan minyak yang tinggi. Perubahan fcnologi tanaman akibat manipulasi lingkungan mengubah komponen minyak dan mutu menthol. Fcnologi tanaman yang memiliki petumbuhan vegetatif maupun reproduktif yang baik menghasil¬ kan menthol tinggi dan menthofuran rendah. Penambahan cahaya 4 jam mulai umur 30 hari setelah tanam menghasilkan minyak dengan kadar menthol paling tinggi yaitu 54.89% dan menthofuran paling rendah yaitu 7.83%.<br /><br />Kata kunci: Hasil, komponen, minyak peppermint, Mentha piperita L., peiode pcncahayaan</p><p> </p><p><strong>ABSTRACT</strong></p><p>Effect ofphotoperiod on the growth, yield and component ofpeppermint oil<br /><br />Research on the effect of photoperiod on the growth, yield and component of peppermints oil of M. piperita, was carried out in the expeimental garden of the Institute for Spice and Medicinal Crops, Lembang West Java, from January to July, 2000. The study was conducted in two steps, i.e. The irst step was manipulation of photo peiod using TL lamps and the second step was distillation and analisis of peppermint oil from their products with gas chromatography and mass spectromctry. The experiment used ive treatments, i.e. (1) control or normal light peiod, (2) four hours light supplement at the age of 30 days and 60 days ater planting, and (3) one hour interruption of dark peiod at the age of 30 days and 60 days. The result showed that the changes in light peiod affected the phenology of the crop. Four hours light supplement at the age of 30 days gave the best vegetative and reproductive growth (morphology of Mentha piperita i.e. flowering, erect stem, tall, wide, large stem, more internodes, leafy, and developed only few stolons). This morphology also resulted in the highest resh mateial and oil product. The change of phenology as the effect of light peiode manipulation could change oil component and inally the quality of menthol. Four hours light supplement at 30 days ater planting showed (he highest menthol content (54.89%) and the lowest menthofuran (7.83%).<br /><br />Keywords: Mentha piperita L., component, photoperiod, yield, peppermint oil</p>


2011 ◽  
Vol 44 (1) ◽  
pp. 7818-7823 ◽  
Author(s):  
S. Mou ◽  
M. Cao ◽  
A.S. Morse

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 409 ◽  
Author(s):  
Dandan Zhao ◽  
Wen-Can Huang ◽  
Na Guo ◽  
Shuye Zhang ◽  
Changhu Xue ◽  
...  

In this research, a two-step extraction approach was developed for chitin preparation from shrimp shells by utilizing citric acids and deep eutectic solvents (DESs), which effectively removed minerals and proteins. In the first step, minerals of shrimp shells were removed by citric acid, and the demineralization efficiency reached more than 98%. In the second step, the removal of protein was carried out using deep eutectic solvents with the assistance of microwave, and the deproteinization efficiency was more than 88%. The results of scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA) showed that the quality of DES-prepared chitin was comparable to that of traditional acid/alkali-prepared chitin. These results were realized without utilizing hazardous chemicals, which are detrimental to the environment. This research indicates that a DES-based preparation approach has the potential for application in the recovery of biopolymers from natural resources.


2012 ◽  
Vol 433-440 ◽  
pp. 3211-3217
Author(s):  
Sheng Q. Xie ◽  
Yun Ho Tsoi ◽  
Avilash Singh

This paper proposes a vision-based embedded motion control system that is developed in our research group. The system is an integration of three subsystems including, an embedded positioning platform, a vision system for inspection and a crystal reorientation system. The system is used as a positioning platform and crystal reorientation system to automate the crystal reorientation process. This process is important in ensuring that the units are correctly oriented for production processes. The focus of this research is placed on how to develop the embedded positioning platform, the crystal reorientation system, and how to improve the system performances including positioning and reorientation accuracy in high speed operation and quality of inspection. A distributed control architecture has been developed using PIC18F4520 microcontrollers. Tests run on the complete system have shown that the system is capable of a minimum indexing time of 1.53 units per second and a reorientation time of 1.42 seconds.


2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Mengji Shi ◽  
Kaiyu Qin

The paper provides a novel cooperative motion scheme for networked Unmanned Aerial Vehicles (UAVs) to fully sweep-cover a priori unknown elongated areas with curved borders, which are termed “valley areas.” The UAVs’ motion is confined between the borders. Different from former research on straight-corridor-sweep-coverage, in each valley area, the width of different portions varies dramatically: the UAVs need to line up across the valley area to achieve full coverage of the widest portions while they can only pass through the narrowest parts one by one in a queue. The UAVs are provided with barrier detection and inter-UAV communication. According to the scheme, a distributed control law has been offered for discrete-time multi-UAV systems, guaranteeing crash avoidance and full coverage while considering the constrained mobility of the UAVs. Regular and extreme simulations are carried out to verify the efficacy and stability of the proposed algorithm. Solutions to U-shaped valley coverage and the case of insufficient UAVs available are discussed with validation simulations. Comparison simulations are conducted with respect to a line-sweep-coverage algorithm developed by a closely related work, and differences in performance are revealed subsequently. Conclusions are drawn with possible directions of future research.


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