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Walker, David W. (author), Vergopolan, Noemi (author), Cavalcante, Louise (author), Smith, Kelly Helm (author), Agoungbome, David (author), Almagro, André (author), Apurv, Tushar (author), Dahal, Nirmal Mani (author), Hoffmann, David (author)Flash droughts, characterized by rapid onset and intensification, are increasingly occurring as a consequence of climate change and rising temperatures. However, existing hydrometeorological definitions fail to encompass the full range of flash droughts, many of which have distinct local physical attributes. Consequently, these events often...journal article 2023
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Leitenstorfer, Alfred (author), Moskalenko, Andrey S. (author), Kampfrath, Tobias (author), Kono, Junichiro (author), Kim, Ki Yong (author), Zhang, Xi Cheng (author), Walker, Christopher (author), Gao, J.R. (author), Li, Chong (author)Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz-∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past...review 2023
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Francis, Diana (author), Fonseca, Ricardo (author), Mattingly, Kyle S. (author), Lhermitte, S.L.M. (author), Walker, Catherine (author)Pine Island Glacier (PIG) has recently experienced increased ice loss that has mostly been attributed to basal melt and ocean ice dynamics. However, atmospheric forcing also plays a role in the ice mass budget, as besides lower-latitude warm air intrusions, the steeply sloping terrain that surrounds the glacier promotes frequent Foehn winds. An...journal article 2023
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Hadjisotiriou, Sophie (author), Marchau, V.A.W.J. (author), Walker, W.E. (author), Rikkert, Marcel Olde (author)Policymakers around the world were generally unprepared for the global COVID-19 pandemic. As a result, the virus has led to millions of cases and hundreds of thousands of deaths. Theoretically, the number of cases and deaths did not have to happen (as demonstrated by the results in a few countries). In this pandemic, as in other great disasters,...journal article 2023
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Clegg, Stewart (author), Loosemore, Martin (author), Walker, Derek (author), van Marrewijk, A.H. (author), Sankaran, Shankar (author)This chapter presents a holistic investigation into construction culture from an organisation studies as well as project management perspective, mobilising the concept of toxic project cultures as a novel conceptual lens to explore new ways to transform the construction industry into a more dynamic, innovative, and socially responsible sector...book chapter 2023
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Gaspar Silva, Jose Rui (author), Finkel, M. (author), Laauwen, Wouter M. (author), Yates, S.J.C. (author), Mirzaei, B. (author), Vercruyssen, N. (author), Young, Abram (author), Walker, Christopher (author), Gao, J.R. (author)We have simulated and measured the beam properties of lens-antenna coupled hot electron bolometer mixers at a few supra-terahertz frequencies between 1.4 and 5.3 THz. The quasi-optical structures consist of an elliptical lens and a logarithmic spiral antenna. The model used for our simulations consists of a finite-element analysis to simulate...journal article 2023
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Gasparsilva, Jose Rui (author), Finkel, M. (author), Laauwen, Wouter (author), Westerweld, Menno (author), More, Nikhil (author), Young, Abram (author), Kulesa, Craig (author), Walker, Christopher (author), Van der Tak, Floris (author), Gao, J.R. (author)We report a high accuracy pointing technique for quasi-optical hot electron bolometer (HEB) mixers in focal-plane arrays designed to operate at 1.4, 1.9, and 4.7 THz. The high accuracy pointing is achieved by prealignment of a HEB chip to a lens, measuring the angular error of each mixer in an array assembly, and then realignment of the chip...journal article 2022
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Walker, C (author), Kusela, C. (author), Young, A (author), Verts, W. (author), Gao, J.R. (author), Hu, Qing (author), Silva, J. R.G. (author), Mirzaei, B. (author), Laauwen, Wouter (author)Gal/Xgal U/LDB Spectroscopic/ Stratospheric THz Observatory (GUSTO) is a NASA Explorers Mission of Opportunity that will make large scale maps of the Milky Way and Large Magellanic Cloud in three important interstellar lines: [CII], [OI], and [NII] at 158, 63, and 205 μm, respectively. During its ~75 day stratospheric (~36 km) flight, GUSTO’s 0...conference paper 2022
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Walker, J.M. (author), Coraddu, A. (author), Garofano, V. (author), Oneto, Luca (author)The development of fast and accurate intelligent vessel control systems is a necessary milestone on the path toward operating autonomous marine vehicles effectively in harsh environments and complex mission settings. One of the main problems of existing control systems is the disparity between the forecasted behaviour and how the vessel actually...journal article 2022
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van Cranenburgh, S. (author), Wang, Shenhao (author), Vij, Akshay (author), Pereira, Francisco (author), Walker, Joan (author)Since its inception, the choice modelling field has been dominated by theory-driven modelling approaches. Machine learning offers an alternative data-driven approach for modelling choice behaviour and is increasingly drawing interest in our field. Cross-pollination of machine learning models, techniques and practices could help overcome problems...journal article 2022
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Ramesh Reddy, L. (author), Milano, Daniel (author), Walker, John (author), Viré, A.C. (author)The hydrodynamic characteristics are crucial for accurately analysing floating offshore wind systems. In this paper, the added mass and damping coefficients of a semisubmersible floater are examined around the natural periods of the surge, heave, and pitch motion, using computational fluid dynamics (CFD). The OpenFOAM CFD setup is validated...journal article 2022
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Coraddu, A. (author), Kalikatzarakis, Miltiadis (author), Walker, J.M. (author), Ilardi, Davide (author), Oneto, Luca (author)The purpose of this chapter is to provide an overview of the state-of-the-art and future perspectives of Data Science and Advanced Analytics for Shipping Energy Systems. Specifically, we will start by listing the different static and dynamic data sources and knowledge base available in this particular context. Then we will review the Data...book chapter 2022
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StrainGE: a toolkit to track and characterize low-abundance strains in complex microbial communitiesvan Dijk, L.R. (author), Walker, Bruce J. (author), Straub, Timothy J. (author), Worby, Colin J. (author), Grote, Alexandra (author), Schreiber, Henry L. (author), Anyansi, C.A. (author), Pickering, Amy J. (author), Hultgren, Scott J. (author), Manson, Abigail L. (author), Abeel, T.E.P.M.F. (author), Earl, Ashlee M. (author)Human-associated microbial communities comprise not only complex mixtures of bacterial species, but also mixtures of conspecific strains, the implications of which are mostly unknown since strain level dynamics are underexplored due to the difficulties of studying them. We introduce the Strain Genome Explorer (StrainGE) toolkit, which...journal article 2022
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Topputo, F. (author), Merisio, G. (author), Cervone, A. (author), Speretta, S. (author), Menicucci, A. (author), Turan, E. (author), Bertels, E. (author), Vennekens, Johan (author), Walker, R (author)The Lunar Meteoroid Impacts Observer (LUMIO) is a CubeSat mission to observe, quantify, and characterize the meteoroid impacts on the lunar farside by detecting their flashes. This complements the knowledge gathered by Earth-based observations of the lunar nearside, thus synthesizing global information on the lunar meteoroid environment and...journal article 2022
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Walker, J.M. (author), Coraddu, A. (author), Collu, Maurizio (author), Oneto, Luca (author)The number of installed floating offshore wind turbines (FOWTs) has doubled since 2017, quadrupling the total installed capacity, and is expected to increase significantly over the next decade. Consequently, there is a growing consideration towards the main challenges for FOWT projects: monitoring the system’s integrity, extending the...journal article 2021
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Guyot, Adrien (author), Pudashine, Jayaram (author), Uijlenhoet, R. (author), Protat, Alain (author), Pauwels, Valentijn R.N. (author), Louf, Valentin (author), Walker, Jeffrey P. (author)The monitoring of wildfire smoke is important to help mitigate impacts on people such as by sending early warnings to affected areas. Received signal levels (RSLs) from radio links have been used as an opportunistic way to accurately measure rainfall and humidity. Radio links provide integrated measurements along their paths and are an...journal article 2021
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Mirzaei, B. (author), Gan, Y. (author), Finkel, M. (author), Groppi, Christopher (author), Young, Abram (author), Walker, Christopher (author), Hu, Qing (author), Gao, J.R. (author)A full demonstration of the Fourier phase grating used as 4.7 THz local oscillator (LO) multiplexer for Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) is presented in this paper, including its design, modeling, tolerance analysis, and experimental characterizations of the angular and intensity distributions among 2 ×...journal article 2021
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Walker, J.M. (author), Coraddu, A. (author), Oneto, Luca (author), Kilbourn, Stuart (author)The number of installed Floating Offshore Wind Turbines (FOWTs) has doubled since 2017, quadrupling the total installed capacity, and is expected to increase significantly over the next decade. Consequently, there is a growing consideration towards the main challenges for FOWT projects: monitoring the system's integrity, extending the...conference paper 2021
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van Dorsser, Cornelis (author), Taneja, P. (author), Walker, W.E. (author), Marchau, V.A.W.J. (author)Policymakers need to make policies for an uncertain future, and policy analysts assist policymakers in choosing preferred courses of action. Despite a longstanding recognition that the futures field can contribute a great deal to policy analysis, futures work is not used to its full potential as an element of policy analysis. This is partly due...journal article 2020
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Wong, S.D. (author), Chorus, C.G. (author), Shaheen, Susan A. (author), Walker, Joan L. (author)Regret is often experienced for difficult, important, and accountable choices. Consequently, we hypothesize that random regret minimization (RRM) may better describe evacuation behavior than traditional random utility maximization (RUM). However, in many travel related contexts, such as evacuation departure timing, specifying choice sets can...journal article 2020