Safe, Aggressive Quadrotor Flight via Reachability-Based Trajectory Design

2019 ◽  
Author(s):  
Shreyas Kousik ◽  
Patrick Holmes ◽  
Ram Vasudevan
Keyword(s):  
Tracking Error ◽  
Search And Rescue ◽  
The Other ◽  
Trajectory Design ◽  
Limited Information ◽  
Receding Horizon ◽  
Cluttered Environments ◽  
Online Planning ◽  
Infrastructure Inspection ◽  
Horizon Planning

Abstract Quadrotors can provide services such as infrastructure inspection and search-and-rescue, which require operating autonomously in cluttered environments. Autonomy is typically achieved with receding-horizon planning, where a short plan is executed while a new one is computed, because sensors receive limited information at any time. To ensure safety and prevent robot loss, plans must be verified as collision free despite uncertainty (e.g, tracking error). Existing spline-based planners dilate obstacles uniformly to compensate for uncertainty, which can be conservative. On the other hand, reachability-based planners can include trajectory-dependent uncertainty as a function of the planned trajectory. This work applies Reachability-based Trajectory Design (RTD) to plan quadrotor trajectories that are safe despite trajectory-dependent tracking error. This is achieved by using zonotopes in a novel way for online planning. Simulations show aggressive flight up to 5 m/s with zero crashes in 500 cluttered, randomized environments.

scholarly journals Bridging the gap between safety and real-time performance in receding-horizon trajectory design for mobile robots

2020 ◽  
Vol 39 (12) ◽  
pp. 1419-1469
Author(s):  
Shreyas Kousik ◽  
Sean Vaskov ◽  
Fan Bu ◽  
Matthew Johnson-Roberson ◽  
Ram Vasudevan
Keyword(s):  
Real Time ◽  
Autonomous Robots ◽  
Tracking Error ◽  
Random Trees ◽  
Model Complexity ◽  
Trajectory Design ◽  
Receding Horizon ◽  
Decomposition Approach ◽  
System Decomposition ◽  
Hardware Platforms

To operate with limited sensor horizons in unpredictable environments, autonomous robots use a receding-horizon strategy to plan trajectories, wherein they execute a short plan while creating the next plan. However, creating safe, dynamically feasible trajectories in real time is challenging, and planners must ensure persistent feasibility, meaning a new trajectory is always available before the previous one has finished executing. Existing approaches make a tradeoff between model complexity and planning speed, which can require sacrificing guarantees of safety and dynamic feasibility. This work presents the Reachability-based Trajectory Design (RTD) method for trajectory planning. RTD begins with an offline forward reachable set (FRS) computation of a robot’s motion when tracking parameterized trajectories; the FRS provably bounds tracking error. At runtime, the FRS is used to map obstacles to parameterized trajectories, allowing RTD to select a safe trajectory at every planning iteration. RTD prescribes an obstacle representation to ensure that obstacle constraints can be created and evaluated in real time while maintaining safety. Persistent feasibility is achieved by prescribing a minimum sensor horizon and a minimum duration for the planned trajectories. A system decomposition approach is used to improve the tractability of computing the FRS, allowing RTD to create more complex plans at runtime. RTD is compared in simulation with rapidly-exploring random trees and nonlinear model-predictive control. RTD is also demonstrated in randomly crafted environments on two hardware platforms: a differential-drive Segway and a car-like Rover. The proposed method is safe and persistently feasible across thousands of simulations and dozens of real-world hardware demos.

Rancang Bangun Sistem Informasi Zakat Infaq Shodaqoh Menggunakan Metodologi Extreme Programming

2018 ◽  
Vol 9 (1) ◽  
pp. 31-42
Author(s):  
Rysa Sahrial
Keyword(s):  
Information System ◽  
The Other ◽  
Extreme Programming ◽  
Limited Time ◽  
Limited Information ◽  
Research Information ◽  
Development Method ◽  
Know How ◽  
Five Factors ◽  
Research Information System

Poverty is one continuing social issue which is hard to solve. Dealing with this problem, Islam has already had the alternative solution that is tithe (Zakat). Zakat is implemented to decrease economy imbalanced appeared in the society. While in fact, not all the Moslem pay Zakat. There are five factors as the reason why Moslem didn’t do that. First, some Muzakki wants to deliver his zakat directly.Seconde, not all Muzakki know how much Zakat must be paid. The other factors are Limited information about Mustahik home, limited time that Muzakki have to deliver his Zakat directly and the easiness to report Mustahik data. Dealing with those factors, it is required to have an information system which can make Muzakki meets Mustahik. In this research, information system application used Extreme Programming (XP) development method. XP method is required to program a system which will be made by accomodating the users’ needs and expectations.

Smelling in Stereo

Secret Worlds ◽  
2021 ◽  
pp. 136-159
Author(s):  
Martin Stevens
Keyword(s):  
Search And Rescue ◽  
The Other ◽  
Sensory Receptors ◽  
Working Relationship ◽  
Olfactory Sensilla ◽  
Insect Olfaction ◽  
Sense Of Smell ◽  
Companion Dogs ◽  
Sound Detection ◽  
The World

This chapter discusses the sense of smell of animals. One way of acquiring information from chemicals in the world is through smell. Just as with the other senses, smell is used for many things, from finding food, judging relatedness and kin, locating and assessing potential mates, marking and defending territories, and much more. The chapter focuses first on ants, which are quite representative of how olfaction broadly works in nature. Located on the antennae of many insects are the main sensory receptors for encoding aspects of the world, from temperature and humidity through to pressure. In insect olfaction, the organs in which the receptors are housed are the olfactory sensilla. Meanwhile, the sense of smell of dogs has contributed to their long working relationship with humans, from help in hunting to search and rescue. After being domesticated for so long, dogs are also extremely good at reading humans, and this has clearly been a valuable trait for breeders in producing a variety of working and companion dogs. Finally, the chapter looks at the eastern American mole, which is one of the several mammals that has been shown to smell in stereo. The findings in the stereo mole essentially parallel some of the features of sound detection, rather like the way in which owls zero in on hidden prey based on the noises they make.

Organizational Commitment Of Afad Istanbul Search And Rescue Unit

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Karakoç ◽  
Ö Erdoğan ◽  
E Demirbaş
Keyword(s):  
Public Health ◽  
Organizational Commitment ◽  
Data Collection ◽  
Internal Consistency ◽  
Bachelor's Degree ◽  
Search And Rescue ◽  
The Other ◽  
Public Health Issue ◽  
International Level ◽  
Significant Public Health

Abstract Background Our study is intended to evaluate the Organizational Commitment of the Istanbul AFAD Search and Rescue Unit (AKB) employees operating at national and international level during disasters and to serve as a model for the other organizations that conduct national and international operations in the area of search and rescue. Methods This research was carried out with a total of 75 employees from Istanbul AFAD AKB from 02.11.18 to 01.01.2019. Introductory Information Form and Organizational Commitment Scale were used for data collection. Findings of the study were evaluated via IBM SPSS Statistics 22. Results Among 71 persons who participated in the study, it was determined that 91.5% were male, 50.7% were at the age of 40 or older, 81.7% were married, 67.6% had bachelor's degree, 63.4% were search and rescue technicians, and 50.7% were employed by their current organization for 10 years or less. Regarding the employees, it was found that 25.4% had very good organizational commitment while 54.9% faced issues in relation to the organizational commitment. OCS point average of the employees was 3.07±0.20 and the obtained Cronbach Alfa internal consistency coefficient of the scale was 0.678. OCS points of those employed for 12 years or longer in total were determined to be high at statistically significant level. Also, OCS points of those who did not face any issue in relation to the Organizational Commitment were found to be high at a statistically significant level against those who faced issues. Conclusions It is important to ensure work satisfaction, provide harmonization, and avert chaos and stress for boosting the organizational commitment. Therefore, the managers should conduct activities intended to boost the employee commitment levels within the organization. Key messages Disaster is a significant public health issue and disaster employees are special. The issues faced by the employees that perform search and rescue operations must be considered important and resolved.

Variations in ATP7B in cats with primary copper-associated hepatopathy

2019 ◽  
Vol 22 (8) ◽  
pp. 753-759
Author(s):  
Hajime Asada ◽  
James K Chambers ◽  
Mari Kojima ◽  
Yuko Goto-Koshino ◽  
Taisuke Nakagawa ◽  
...  
Keyword(s):  
The Other ◽  
Copper Accumulation ◽  
Limited Information ◽  
Single Nucleotide ◽  
Serum Ceruloplasmin ◽  
Hepatic Copper ◽  
Single Nucleotide Variations ◽  
Tissue Specimens ◽  
Ceruloplasmin Activity ◽  
Low Serum

Objectives Primary copper-associated hepatopathy (PCH) has been reported in young cats. Although our group recently reported a young cat with PCH harbouring single-nucleotide variations in ATP7B, limited information is available regarding its association with the pathogenesis of feline PCH. The objective of this study was to investigate the prevalence of ATP7B variations in cats with PCH. Methods Rhodanine staining was performed to detect hepatic copper accumulation (HCA) in intraoperative liver tissue specimens from 54 cats. In cats with HCA, variations in ATP7B and COMMD1 and serum ceruloplasmin activity were analysed. Results Based on age, liver histopathological findings and hepatic distribution of accumulated copper, PCH was suspected in 4/54 cats. Sequence analysis of ATP7B and COMMD1 revealed single-nucleotide variations in ATP7B in 3/4 cats with PCH. Among the cats with PCH, one showed remarkably low serum ceruloplasmin activity, while the other three did not. Conclusions and relevance The results of this study suggest that some cats with PCH harbour single-nucleotide variations in ATP7B, suggesting that feline PCH is an equivalent disorder to human Wilson’s disease. This study provides basic evidence facilitating further studies of the pathophysiology and treatment of feline PCH.

The Canadian Legal Profession

1986 ◽  
Vol 11 (3) ◽  
pp. 447-532 ◽  
Author(s):  
H. W. Arthurs ◽  
R. Weisman ◽  
F. H. Zemans
Keyword(s):  
United States ◽  
Legal Profession ◽  
The United States ◽  
The Other ◽  
Limited Information ◽  
Canadian Experience ◽  
Institutional Structures ◽  
Legal Professions ◽  
Canadian Provinces ◽  
High Degree

This article seeks to weave together the limited information available on the legal professions of the Canadian provinces. Following the same general format as the other comparative studies in this series, it also offers several critical observations of special interest to readers in the United States, whose experience the Canadian bar so closely tracks. The phenomenon of stratification—familiar to American observers—is clearly visible in the Canadian legal profession. Combined with other centrifugal forces, it threatens the unity of a profession which, until recently, has managed to preserve a high degree of cohesion in training, ideology, and institutional structures. On the other hand, in certain respects, the Canadian experience seems to differ from that of the United States, especially in the strength and peculiar structure of publicly funded legal aid schemes, in the profession's continuing formal autonomy and relative immunity from public regulation, and in its long-lasting attachment to apprenticeship as a necessary stage in professional formation. These and other convergences and divergences between the two countries raise questions of general significance: To what extent do the similarities between Canada and the United States verify the assumption implicit in the theoretical literature (principally Abel, Freidson, and Larson) that there is an empirical referent for something called legal professionalism? And to what extent do the differences suggest that containing societies contribute distinctive characteristics to their legal professions, whose qualities are therefore highly contingent?

An Investigation of the Effect of Latency on the Operator’s Trust and Performance for Manual Multi-robot Teleoperated Tasks

2017 ◽  
Vol 61 (1) ◽  
pp. 390-394 ◽  
Author(s):  
Hunter Rogers ◽  
Amro Khasawneh ◽  
Jeffery Bertrand ◽  
Kapil Chalil Madathil
Keyword(s):  
Confidence Level ◽  
Search And Rescue ◽  
The Other ◽  
Repeated Measure ◽  
Independent Variables ◽  
Subjective Workload ◽  
Dependent Variables ◽  
Independent Variable ◽  
And Performance ◽  
Two Independent Variables

Latency is an important factor when conducting teleoperated missions. This study investigates the effects of latency on a set of dependent variables: performance (measured by time and number of errors), subjective workload, trust, and usability. These measures were tested in a simulated search-and-rescue mission over two levels of two independent variables. One independent variable was the number of robots – one or two (within-subject), and the other independent variable was latency – simulations with and without latency (between-subject.) The significant effect of the independent variables on the dependent variables were checked using repeated measure two-way ANOVA with a confidence level of 95%. The data determined any significant effects that latency and/or the number of robots had on such factors as errors, dependability, reliability, harmful outcomes, temporal demand, and frustration.

Haul-out behaviour of two Ross seals off eastern Antarctica

2003 ◽  
Vol 15 (2) ◽  
pp. 257-258 ◽  
Author(s):  
COLIN SOUTHWELL
Keyword(s):  
Observational Data ◽  
Observational Studies ◽  
The Other ◽  
Accurate Assessment ◽  
Limited Information ◽  
Absolute Sense ◽  
Crabeater Seal ◽  
Abundance Estimates ◽  
Antarctic Seals ◽  
Using Data

Accurate assessment of the abundance of pinnipeds from visual surveys requires estimation of both the available (hauled-out) and unavailable (in-water) components of the population (Eberhardt et al. 1979). Continental estimates of the abundance of the four Antarctic seals are based on limited information on haul-out behaviour. In developing continental estimates, Erickson & Hanson (1990) corrected visual surveys of the hauled-out component of the species' populations using data from observational studies of haulout behaviour by Erickson et al. (1989). Erickson & Hanson (1990) point out that, because the observational studies did not account for an unknown fraction of seals that remained in the water during the peak haul-out period, their abundance estimates are minimum values. Further, Erickson & Hanson (1990) corrected the visual surveys for all four species using haul-out data for the crabeater seal only, as observational data for the other species were not available. This assumes that haul-out patterns are constant across species, which is largely untested. Consequently, there is potential for bias, in both a relative and absolute sense, in the estimated abundance of Antarctic seals.

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