Yonas Zewdu Ayele

Dr. Yonas Zewdu Ayele


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 October 2021 in Sustainability
Verified
Journal Article
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MAMostafa Aliyari
Mostafa Aliyari
Enrique DroguettEnrique Droguett
Enrique Droguett
YAYonas Zewdu Ayele
Yonas Zewdu Ayele
As bridge inspection becomes more advanced and more ubiquitous, artificial intelligence (AI) techniques, such as machine and deep learning, could offer suitable solutions to the nation’s problems of overdue bridge inspections. AI coupling with various data that can be captured by unmanned aerial vehicles (UAVs) enables fully automated bridge inspections. The key to the success of automated bridge inspection is a model capable of detecting failures from UAV data like images and films. In this context, this paper investigates the performances of state-of-the-art convolutional neural networks (CNNs) through transfer learning for crack detection in UAV-based bridge inspection. The performance of different CNN models is evaluated via UAV-based inspection of Skodsberg Bridge, located in eastern Norway. The low-level features are extracted in the last layers of the CNN models and these layers are trained using 19,023 crack and non-crack images. There is always a trade-off between the number of trainable parameters that CNN models need to learn for each specific task and the number of non-trainable parameters that come from transfer learning. Therefore, selecting the optimized amount of transfer learning is a challenging task and, as there is not enough research in this area, it will be studied in this paper. Moreover, UAV-based bridge inception images require specific attention to establish a suitable dataset as the input of CNN models that are trained on homogenous images. However, in the real implementation of CNN models in UAV-based bridge inspection images, there are always heterogeneities and noises, such as natural and artificial effects like different luminosities, spatial positions, and colors of the elements in an image. In this study, the effects of such heterogeneities on the performance of CNN models via transfer learning are examined. The results demonstrate that with a simplified image cropping technique and with minimum effort to preprocess images, CNN models can identify crack elements from non-crack elements with 81% accuracy. Moreover, the results show that heterogeneities inherent in UAV-based bridge inspection data significantly affect the performance of CNN models with an average 32.6% decrease of accuracy of the CNN models. It is also found that deeper CNN models do not provide higher accuracy compared to the shallower CNN models when the number of images for adoption to a specific task, in this case crack detection, is not large enough; in this study, 19,023 images and shallower models outperform the deeper models.

24 September 2023 in Sensors
Verified
Journal Article
Open access
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Samson Ogheneovo OrumaSamson Ogheneovo Oruma
Samson Ogheneovo Oruma
YAYonas Zewdu Ayele
Yonas Zewdu Ayele
FSFabien Sechi
Fabien Sechi
HRHanne Rødsethol
Hanne Rødsethol
Background: As social robots increasingly integrate into public spaces, comprehending their security implications becomes paramount. This study is conducted amidst the growing use of social robots in public spaces (SRPS), emphasising the necessity for tailored security standards for these unique robotic systems. Methods: In this systematic mapping study (SMS), we meticulously review and analyse existing literature from the Web of Science database, following guidelines by Petersen et al. We employ a structured approach to categorise and synthesise literature on SRPS security aspects, including physical safety, data privacy, cybersecurity, and legal/ethical considerations. Results: Our analysis reveals a significant gap in existing safety standards, originally designed for industrial robots, that need to be revised for SRPS. We propose a thematic framework consolidating essential security guidelines for SRPS, substantiated by evidence from a considerable percentage of the primary studies analysed. Conclusions: The study underscores the urgent need for comprehensive, bespoke security standards and frameworks for SRPS. These standards ensure that SRPS operate securely and ethically, respecting individual rights and public safety, while fostering seamless integration into diverse human-centric environments. This work is poised to enhance public trust and acceptance of these robots, offering significant value to developers, policymakers, and the general public.

22 September 2021 in Energies
Verified
Journal Article
Open access
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KAKamal Achuthan
Kamal Achuthan
NHNick Hay
Nick Hay
MAMostafa Aliyari
Mostafa Aliyari
YAYonas Zewdu Ayele
Yonas Zewdu Ayele
Unmanned aerial systems (UAS) provide two main functions with regards to bridge inspections: (1) high-quality digital imaging to detect element defects; (2) spatial point cloud data for the reconstruction of 3D asset models. With UAS being a relatively new inspection method, there is little in the way of existing framework for storing, processing and managing the resulting inspection data. This study has proposed a novel methodology for a digital information model covering data acquisition through to a 3D GIS visualisation environment, also capable of integrating within a bridge management system (BMS). Previous efforts focusing on visualisation functionality have focused on BIM and GIS as separate entities, which has a number of problems associated with it. This methodology has a core focus on the integration of BIM and GIS, providing an effective and efficient information model, which provides vital visual context to inspectors and users of the BMS. Three-dimensional GIS visualisation allows the user to navigate through a fully interactive environment, where element level inspection information can be obtained through point-and-click operations on the 3D structural model. Two visualisation environments were created: a web-based GIS application and a desktop solution. Both environments develop a fully interactive, user-friendly model which have fulfilled the aims of coordinating and streamlining the BMS process.

17 June 2016 in Journal of Offshore Mechanics and Arctic Engineering
Verified
Journal Article
Closed access
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YAYonas Zewdu Ayele
Yonas Zewdu Ayele
JBJavad Barabady
Javad Barabady
Enrique DroguettEnrique Droguett
Enrique Droguett
The increased complexity of Arctic offshore drilling waste handling facilities, coupled with stringent regulatory requirements such as zero “hazardous” discharge, calls for rigorous risk management practices. To assess and quantify risks from offshore drilling waste handling practices, a number of methods and models are developed. Most of the conventional risk assessment approaches are, however, broad, holistic, practical guides or roadmaps developed for off-the-shelf systems, for non-Arctic offshore operations. To avoid the inadequacies of traditional risk assessment approaches and to manage the major risk elements connected with the handling of drilling waste, this paper proposes a risk assessment methodology for Arctic offshore drilling waste handling practices based on the dynamic Bayesian network (DBN). The proposed risk methodology combines prior operating environment information with actual observed data from weather forecasting to predict the future potential hazards and/or risks. The methodology continuously updates the potential risks based on the current risk influencing factors (RIF) such as snowstorms, and atmospheric and sea spray icing information. The application of the proposed methodology is demonstrated by a drilling waste handling scenario case study for an oil field development project in the Barents Sea, Norway. The case study results show that the risk of undesirable events in the Arctic is 4.2 times more likely to be high (unacceptable) environmental risk than the risk of events in the North Sea. Further, the Arctic environment has the potential to cause high rates of waste handling system failure; these are between 50 and 85%, depending on the type of system and operating season.

14 September 2015 in International Journal of System Assurance Engineering and Management
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YAYonas Zewdu Ayele
Yonas Zewdu Ayele
ABA. Barabadi
A. Barabadi
JBJ. Barabady
J. Barabady

1 April 2016 in Journal of Offshore Mechanics and Arctic Engineering
Verified
Journal Article
Closed access
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YAYonas Zewdu Ayele
Yonas Zewdu Ayele
Abbas BarabadiAbbas Barabadi
Abbas Barabadi
Enrique DroguettEnrique Droguett
Enrique Droguett
As oil and gas companies in the Arctic attempt to maximize the value of each project and optimize their portfolio of investment opportunities, it has become vital to evaluate drilling waste handling practices for their cost-effectiveness in order to support strategic decisions. Identifying cost-effective waste handling practices, which have a minimal environmental footprint, however, is one of the biggest challenges for Arctic offshore industries. The cost and potential risks of drilling waste handling practices in the Arctic offshore operation will differ vastly, depending on the operating environment such as the ice conditions and negative sea temperature. However, in the majority of the available cost-effectiveness and risk analysis literature, the influence of the operating environment on the cost and risk profile has received less attention. Hence, the aim of this paper is to propose a methodology for risk-based cost-effectiveness analysis (RB–CEA) of drilling waste handling practices by considering the complex and fast-changing nature of the Arctic. The central thrust of this paper is to highlight the fact that comparing different alternatives based on the cost elements alone is misleading. The proposed methodology uses risk assessment as a key component for the cost-effectiveness analysis (CEA). The application of the proposed methodology is demonstrated by a case study of the drilling waste handling practices of an oil field in the Barents Sea. The case study results demonstrate that the operating environment causes costs to be between 1.18 and 1.52 times greater, depending on the type of practices and operating season, in the Arctic offshore compared with the North Sea. Further, the risk of undesirable events is between 1.48 and 2.60 times greater during waste handling activities under Arctic operational conditions.