scholarly journals A Bayesian Approach to Risk-Based Autonomy for a Robotic System Executing a Sequence of Independent Tasks

2021 ◽  
Author(s):  
Sverre Velten Rothmund ◽  
Christoph Alexander Thieme ◽  
Ingrid Bouwer Utne ◽  
Tor Arne Johansen
Keyword(s):  
Time Use ◽  
Robotic System ◽  
Decision Network ◽  
New Information ◽  
Internal Faults ◽  
Ultrasound Inspection ◽  
State Of The Environment ◽  
Over Time ◽  
Independent Tasks

Enabling higher levels of autonomy requires an increased ability to identify and handle internal faults and unforeseen changes in the environment. This work presents an approach to improve this ability for a robotic system executing a series of independent tasks, such as inspection, sampling, or intervention, at different locations. A dynamic decision network (DDN) is used to infer the presence of internal faults and the state of the environment by fusing information over time. This knowledge is used to make risk-informed decisions enabling the system to proactively avoid failure and to minimize the consequence of faults. Past states are evaluated with new information to identify and counteract previous sub-optimal actions. A case study on an inspection drone tasked with contact-based ultrasound inspection is presented. The case study successfully demonstrates the proposed capabilities while minimizing time use and maximizing mission completion.

scholarly journals A Bayesian Approach to Risk-Based Autonomy for a Robotic System Executing a Sequence of Independent Tasks

2021 ◽  
Author(s):  
Sverre Velten Rothmund ◽  
Christoph Alexander Thieme ◽  
Tor Arne Johansen ◽  
Ingrid Bouwer Utne
Keyword(s):  
Robotic System ◽  
Industrial Facility ◽  
Decision Network ◽  
New Information ◽  
Time Usage ◽  
Current Task ◽  
Internal Faults ◽  
Ultrasound Inspection ◽  
State Of The Environment ◽  
Independent Tasks

Enabling higher levels of autonomy requires an increased ability to identify and handle internal faults and unforeseen changes in the environment. This work presents an approach to improve this ability for a robotic system that is executing a series of independent tasks, such as inspection, sampling, or intervention, at different locations. A dynamic decision network (DDN) is used to infer the presence of internal faults and the state of the environment based on the available measurements. This knowledge is used to evaluate the risk of executing the current task, which is used to evaluate whether the task should be executed or skipped and whether maintenance actions are needed. Evaluating past states given new information is used to identify skipped tasks that should be revisited. The proposed approach is implemented for a drone tasked with contact-based ultrasound inspection of an industrial facility. The drone is able to successfully distinguish between different internal faults and adverse environmental states and act accordingly. The system makes risk-informed decisions based on uncertain knowledge, enabling it to minimize the time usage while minimizing the potential of harming the drone and maximizing mission completion.<br>

scholarly journals A Bayesian Approach to Risk-Based Autonomy for a Robotic System Executing a Sequence of Independent Tasks

2021 ◽  
Author(s):  
Sverre Velten Rothmund ◽  
Christoph Alexander Thieme ◽  
Tor Arne Johansen ◽  
Ingrid Bouwer Utne
Keyword(s):  
Robotic System ◽  
Industrial Facility ◽  
Decision Network ◽  
New Information ◽  
Time Usage ◽  
Current Task ◽  
Internal Faults ◽  
Ultrasound Inspection ◽  
State Of The Environment ◽  
Independent Tasks

Enabling higher levels of autonomy requires an increased ability to identify and handle internal faults and unforeseen changes in the environment. This work presents an approach to improve this ability for a robotic system that is executing a series of independent tasks, such as inspection, sampling, or intervention, at different locations. A dynamic decision network (DDN) is used to infer the presence of internal faults and the state of the environment based on the available measurements. This knowledge is used to evaluate the risk of executing the current task, which is used to evaluate whether the task should be executed or skipped and whether maintenance actions are needed. Evaluating past states given new information is used to identify skipped tasks that should be revisited. The proposed approach is implemented for a drone tasked with contact-based ultrasound inspection of an industrial facility. The drone is able to successfully distinguish between different internal faults and adverse environmental states and act accordingly. The system makes risk-informed decisions based on uncertain knowledge, enabling it to minimize the time usage while minimizing the potential of harming the drone and maximizing mission completion.<br>

Loosening the Ties that Bind: A Learning Model of Agreement Flexibility

2001 ◽  
Vol 55 (2) ◽  
pp. 289-325 ◽  
Author(s):  
Barbara Koremenos
Keyword(s):  
Formal Model ◽  
Learning Model ◽  
Detailed Case ◽  
New Information ◽  
Limited Duration ◽  
Over Time ◽  
Do So

How can states credibly make and keep agreements when they are uncertain about the distributional implications of their cooperation? They can do so by incorporating the proper degree of flexibility into their agreements. I develop a formal model in which an agreement characterized by uncertainty may be renegotiated to incorporate new information. The uncertainty is related to the division of gains under the agreement, with the parties resolving this uncertainty over time as they gain experience with the agreement. The greater the agreement uncertainty, the more likely states will want to limit the duration of the agreement and incorporate renegotiation. Working against renegotiation is noise—that is, variation in outcomes not resulting from the agreement. The greater the noise, the more difficult it is to learn how an agreement is actually working; hence, incorporating limited duration and renegotiation provisions becomes less valuable. In a detailed case study, I demonstrate that the form of uncertainty in my model corresponds to that experienced by the parties to the Nuclear Non-Proliferation Treaty, who adopted the solution my model predicts.

When Culturally Significant Songs are Decontextualised: The Initiation Song Somagwaza, A Case Study

2018 ◽  
Vol 28 (2) ◽  
Author(s):  
T Dowling ◽  
Somikazi Deyi ◽  
Anele Gobodwana
Keyword(s):  
Qualitative Research ◽  
Comparative Method ◽  
Popular Song ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Ritual Music ◽  
Constant Comparative Method ◽  
Small Focus ◽  
Over Time

While there have been a number of studies on the decontextualisation and secularisation of traditional ritual music in America, Taiwan and other parts of the globe, very little has been written on the processes and transformations that South Africa’s indigenous ceremonial songs go through over time. This study was prompted by the authors’ interest in, and engagement with the Xhosa initiation song Somagwaza, which has been re-imagined as a popular song, but has also purportedly found its way into other religious spaces. In this article, we attempted to investigate the extent to which the song Somagwaza is still associated with the Xhosa initiation ritual and to analyse evidence of it being decontextualised and secularised in contemporary South Africa. Our methodology included an examination of the various academic treatments of the song, an analysis of the lyrics of a popular song, bearing the same name, holding small focus group discussions, and distributing questionnaires to speakers of isiXhosa on the topic of the song. The data gathered were analysed using the constant comparative method of analysing qualitative research.

Thinning in mature eastern white pine: 43-year case study

2002 ◽  
Vol 78 (4) ◽  
pp. 539-549 ◽  
Author(s):  
Paul D Anderson ◽  
John C Zasada ◽  
Glen W Erickson ◽  
Zigmond A Zasada
Keyword(s):  
Genetic Diversity ◽  
Dna Analysis ◽  
Large Diameter ◽  
White Pine ◽  
Thinning Intensity ◽  
Pine Regeneration ◽  
Volume Production ◽  
Pine Stands ◽  
Over Time

A white pine (Pinus strobus L.) stand at the western margin of the species range, approximately 125 years of age at present, was thinned in 1953 from 33.5 m2 ha-1 to target residual basal areas of 18.4, 23.0, 27.5, and 32.1 m2 ha-1 . Repeated measurement over the following 43-years indicated that the greatest total volume production and the greatest number of large diameter trees occurred in the unit of highest residual density. Over time, the distribution of stems was predominantly random although mortality between 1979 and 1996 resulted in a tendency for clumping in the 23.0 and 27.5 m2 ha-1 treatments. DNA analysis indicated that thinning intensity had little effect on the genetic diversity of residual white pine. This study suggests that mature white pine stands in northern Minnesota may be managed at relatively high densities without loss of productivity. However, regardless of overstory density, there was little or no white pine regeneration occurring in this stand. Key words: thinning, growth, genetic diversity, molecular markers, spatial pattern, regeneration

scholarly journals Can politically oriented interventions in built heritage contribute to its authenticity? Erbil Citadel’s Babylonian Gate as a case study

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed Awadh Jasim ◽  
Laura Hanks ◽  
Katharina Borsi
Keyword(s):  
Cultural Value ◽  
Cultural Issues ◽  
Built Heritage ◽  
Projection Screen ◽  
Conflicting Demands ◽  
Existential Issue ◽  
Over Time

AbstractToday, the concept of built heritage authenticity is a projection screen for conflicting demands and thus a ‘contested field’. Short-sighted readings started to drag the concept behind different ill-considered treatises, in which some heritage aspects loosely outweighed other aspects. Archaeological perspectives that tend to freeze heritage structures in time, such as those that are privileged upon other contemporary socio-cultural issues, while political takes also overshadowed other epistemological prospects, and vice versa. Repercussions have made inclusion of what is regarded as ‘inevitable changes’ within the built context problematic as to the re-interpretation and thus assessment of its authenticity. Despite their possible momentary threat to the latter, these changes may add to the cultural value of the context over time, granting new potential that may instead boost its authenticity. This paper investigates the potential continuity of Erbil Citadel’s Babylonian Gate as an inevitable change within the site’s built context by studying the Gate’s controversial political impacts on the context’s authenticity. This study affirms that authenticity is a transcendental value of an open-ended progressive nature, which cannot be reduced to a specific period or properties within the historical chronology of built heritage. Hence, authenticity should be approached as a meaningful existential issue, while revelation of its essence and thus its dimension entails precise scrutiny of both the tangibles and intangibles of the context. However, to be part of its authenticity, any change in the context should be adaptable and possibly incorporated as a new value within its cultural strata, thus enabling progressive support for site authenticity.

scholarly journals A Holistic Framework for Evaluating Adaptation Approaches to Coastal Hazards and Sea Level Rise: A Case Study from Imperial Beach, California

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1324
Author(s):  
David Revell ◽  
Phil King ◽  
Jeff Giliam ◽  
Juliano Calil ◽  
Sarah Jenkins ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Public Trust ◽  
Adaptation Strategy ◽  
Public Benefits ◽  
Study Results ◽  
Local Risk ◽  
Over Time

Sea level rise increases community risks from erosion, wave flooding, and tides. Current management typically protects existing development and infrastructure with coastal armoring. These practices ignore long-term impacts to public trust coastal recreation and natural ecosystems. This adaptation framework models physical responses to the public beach and private upland for each adaptation strategy over time, linking physical changes in widths to damages, economic costs, and benefits from beach recreation and nature using low-lying Imperial Beach, California, as a case study. Available coastal hazard models identified community vulnerabilities, and local risk communication engagement prioritized five adaptation approaches—armoring, nourishment, living shorelines, groins, and managed retreat. This framework innovates using replacement cost as a proxy for ecosystem services normally not valued and examines a managed retreat policy approach using a public buyout and rent-back option. Specific methods and economic values used in the analysis need more research and innovation, but the framework provides a scalable methodology to guide coastal adaptation planning everywhere. Case study results suggest that coastal armoring provides the least public benefits over time. Living shoreline approaches show greater public benefits, while managed retreat, implemented sooner, provides the best long-term adaptation strategy to protect community identity and public trust resources.

Populism and Religion in Brazil: The View from Education Policy

2021 ◽  
pp. 1-15
Author(s):  
Catarina Ianni Segatto ◽  
Mário Aquino Alves ◽  
Andrea Pineda
Keyword(s):  
Education Policy ◽  
Historical Analysis ◽  
Secondary Data ◽  
Right Wing ◽  
Religious Groups ◽  
Welfare Services ◽  
National Congress ◽  
Over Time

This article is a case study of Brazil, a country where Catholic-based organizations have historically played a key role in providing education and welfare services. Since the 1980s, these organizations have supported progressive changes at both the national and subnational levels. Nevertheless, the influence of religion on education policy has shifted in the last few decades. Pentecostal and Neopentecostal groups have gained prominence through representatives in the National Congress, and, in 2018, formed a coalition enabling the election of a right-wing populist President. We analyse the trajectory of religious groups’ influence on Brazil’s education policy over time (colonization to the 1980s, the 1980s to the beginning of the 2000s, and the 2000s until now) through a qualitative-historical analysis of primary and secondary data. This article argues that both Catholic and Protestant groups have influenced progressive changes in Brazil’s education policy, but they also share conservative ideas impeding further advances.

scholarly journals The multiplicity of halal standards: a case study of application to slaughterhouses

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ali Abdallah ◽  
Mohammed Abdel Rahem ◽  
Antonella Pasqualone
Keyword(s):  
Food Products ◽  
Regulatory Framework ◽  
Close Collaboration ◽  
Western Countries ◽  
Production Processes ◽  
Islamic Countries ◽  
Certification And Accreditation ◽  
Over Time

AbstractFood products suitable for Muslim consumers should be halal certified, particularly when their origins or production processes are doubtful. However, there is a multiplicity of halal standards. This situation may generate confusion, particularly for producers in Western countries who would like to certify their products in order to export them to Islamic countries. This study analyzed the reasons underlying the multiplicity of standards and reviewed the attempts of harmonization over time. Then, the case study of application to slaughterhouses was considered, by comparing four different halal standards (namely GSO 993:2015, OIC/SMIIC 1:2019, HAS 23103:2012, and MS 1500:2019) representative of different geographic areas. Animal stunning was critically examined, comparing tradition with modernity. The study evidenced that the basic requirements related to slaughtering are common to all the halal standards considered, but several differences occur in more specific details. Only a close collaboration between the authorities of all the countries involved in issuing halal certifications will lead to a homogeneous regulatory framework with unified certification and accreditation procedures, increasingly required in a globalized market.

scholarly journals Signal Classification Algorithms over Time Selective Channels

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1714
Author(s):  
Mohamed Marey ◽  
Hala Mostafa
Keyword(s):  
Block Code ◽  
Classification Problem ◽  
Classification Performance ◽  
Signal Classification ◽  
Final Decision ◽  
Time Block ◽  
Channel Response ◽  
Over Time ◽  
Parallel Fashion

In this work, we propose a general framework to design a signal classification algorithm over time selective channels for wireless communications applications. We derive an upper bound on the maximum number of observation samples over which the channel response is an essential invariant. The proposed framework relies on dividing the received signal into blocks, and each of them has a length less than the mentioned bound. Then, these blocks are fed into a number of classifiers in a parallel fashion. A final decision is made through a well-designed combiner and detector. As a case study, we employ the proposed framework on a space-time block-code classification problem by developing two combiners and detectors. Monte Carlo simulations show that the proposed framework is capable of achieving excellent classification performance over time selective channels compared to the conventional algorithms.

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