bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Methods for the Identification of Incorrect Microstructures in Grade 91 Power Station Steels
Authors: Wilson John W. , Peyton Anthony J.
Published: January 2022

Grade 91 steels have been used in power generation for more than 20 years in high temperature, high pressure applications such as steam piping, headers and tubing because it provides superior creep and oxidation resistance at elevated temperatures. The mechanical properties of the material are dependent on the creation of a martensitic microstructure, however incorrect heat treatment during manufacture, installation or repair can result in a weak ferritic or semi-ferritic microstructure which can cause premature component failure. Currently, components with incorrect, weak microstructures are identified using hardness testing; a manual technique which is prone to error. This work details a series of tests carried out at the University of Manchester to assess the suitability of multi-parameter magnetic testing for the identification of incorrect microstructures. The tests stem from a workshop organized by the Electric Power Research Institute (EPRI) where three sets of samples (eight pipe sections, eight tube sections and eight unidentified tube sections) with different microstructures were circulated world-wide. The results of the work show that the magnetic measurement techniques employed in these tests have the potential to provide a basis for the development of a portable NDE system for the identification of incorrect microstructures in Grade 91 plant components. The developed system would enable fast scanning of components with very little surface preparation along with digital data storage, improving on current manual hardness testing.
Research on Key Technologies of Precise Measurement of Geographic Coordinates of Subsea Pipelines
Authors: Jian Li , Jialin Wang , Jianyuan Zhao , Mingze Li , Xinjing Huang
Published: January 2022

With the continuous increase of offshore oil and gas exploitation activities, the number of subsea pipelines is becoming larger and larger, which leads to frequent occurrence of subsea pipeline accidents. Long-term safe operation of subsea pipelines can be ensured by regular defect detection. The premise of locating and disposing defects is to accurately measure the geographic coordinates of subsea pipelines. Our research group has put forward a kind of pipeline spherical internal detector (SD), which has the advantages of convenient implementation, low risk to jam. For the SD, this paper has carried out research on the key technology of precise measurement of subsea pipelines’ geographic coordinates using the internal magnetic fields. The main work is as follows:

(1) Magnetic tensor invariant calibration method for magnetometer array has been studied and L-M algorithm is taken to solve the parameters, which is efficient and accurate. Field calibration experiment has proved this method is effective and has good robustness.

(2) A new method of measuring pipeline’s pitch angle is proposed. Under the experimental condition of using AC servo motor to drive the sensor instead of the SD to rotate, the pitch angle measurement error is less than 0.2°.

(3) Magnetic anomaly of spiral weld and buckling pipeline are used as new mark points to calibrate the geographic coordinates of subsea pipelines. Experimental results show that the newly designed SD can successfully identify spiral welds and buckling pipeline.
Leak Detection and Leakage Assessment of Submarine Pipelines Based on Passive Acoustics
Authors: Zhang Yu , Feng Zhu , Rui Xiaobo , Wang Bingpu
Published: January 2022

Passive acoustic is considered to be a more economical and suitable method for long-term monitoring at sea. In this paper, a gas flow measurement method under low signal-to-ratio and overlapping conditions is proposed. The signal-to-noise ratio and measurement stability can be improved through complementary ensemble empirical mode decomposition and adaptive frequency matching. The normalized energy window is used to determine the time period of each bubble to ensure the accuracy of the frequency identification. The accuracy was verified by experiments. The results show that in the flow range of 100–1000mL/min, the measurement error is controlled within 6%. This paper provides insight into low signal-to-noise ratio and high-speed escaping gas flow measurement technology.
Determination of the Ultrasonic Velocity on a Recent and Aged Pine Wood
Authors: Carreon Héctor , Carrillo Mayra
Published: January 2022

Aging in wood is the inevitable modification of physical and mechanical properties due to deterioration caused by different factors such as organisms that destroy wood, photodegradation, weathering or long-term loading. During the wood degradation process, significant mass, stiffness and strength are lost. Therefore, it is relevant to monitor the wood decomposition process to guarantee the structural requirements in buildings. This research work aims to report the influence of degradation in wood due to deterioration through the use of ultrasonic measurements. Longitudinal and transverse ultrasonic velocities were calculated using the ultrasonic emission-transmission technique for aged and unaged Mexican pine (Pinus Strobus) wood. The experimental measurements were carried out using longitudinal and shear wave ultrasonic transducers with a center frequency of 1.0 MHz and 0.5MHz respectively. Scanning electron microscopy (SEM) was performed to establish a direct correlation with the behavior of the ultrasonic wave developed in naturally aged and unaged wood. Measurements revealed higher ultrasonic velocity values for unaged wood samples in longitudinal, tangential and radial directions compared to aged wood samples, but no significant differences were found in all other wood directions.
Detection of Segregation in a High Carbon Steel by Non-Destructive Techniques
Authors: Hernández Luis , Carreón Hector , Jacuinde Arnoldo
Published: January 2022

In high carbon steel manufacture, segregation is a common problem that compromises the quality and performance of cast products. When they are rolled or forged, hard metallurgical phases can develop, promoting material embrittlement. To detect the segregation presence, traditionally, it is analyzed by macro-attack (according to the ASTM 381 standard). However, this methodology is limited to the subjective interpretation of the quality inspector, and also it is dangerous. Non-destructive means represent an agile alternative for quality control because they are sensitive to the chemical composition and microstructure of the steel. Through conventional ultrasound technique, an increase in attenuation coefficient was detected in the area of greater segregation and lower values in regions with greater chemical homogeneity.

On the other hand, the longitudinal wave velocity was lower in the segregated region and higher in the zone with less segregation. Furthermore, by some mathematical relationships and wave speeds, Poisson’s ratio Young’s and shear modulus were obtained, which are related to the ease of rolling in steel. Finally, Eddy currents and impedance plane determined that the segregation region has a lower phase angle, and therefore, a higher electrical conductivity concerning the zones of less segregation.
Transition to Online Cable Insulation Condition Monitoring
Authors: Glass S. W. , Fifield Leonard S. , Spencer Mychal P.
Published: January 2022

Nuclear power plant cables were originally qualified for 40 year life and generally have not required specific test verification to assure service availability through the initial plant qualification period. However, license renewals to 60 and 80 years of operation require a cable aging management program that depends on some form of test and verification to assure fitness for service. Environmental stress (temperature, radiation, chemicals, water, and mechanical) varies dramatically within a nuclear power plant and, in some cases, cables have degraded and required repair or replacement before their qualified end-of-life period. In other cases, cable conditions have been mild and dependable cable performance confirmed to extend well beyond the initial qualified life. Most offline performance-based testing requires cables to be decoupled and de-energized for specially trained technicians to perform testing. These offline tests constitute an expensive operational burden that limits the economic viability of nuclear power plants. Although initial investment may be higher, new online test practices are emerging as options or complements to offline testing that avoid or minimize the regularly scheduled offline test burden. These online methods include electrical and fiber-optic partial discharge measurement, spread spectrum time or frequency domain reflectometry, distributed temperature profile measurements, and local interdigital capacitance measurement of insulation characteristics. Introduction of these methods must be supported by research to confirm efficacy plus either publicly financed or market driven investment to support the start-up expense of cost-effective instrumentation to monitor cable condition and assure reliable operation. This work summarizes various online cable assessment technologies plus introduces a new cable motor test bed to assess some of these technologies in a controlled test environment.
Guided Wave Imaging Based on Fully Connected Neural Network for Quantitative Corrosion Assessment
Authors: Wang Xiaocen , Lin Min , Tong Junkai , Liang Lin , Li Jian , Zeng Zhoumo , Liu Yang
Published: January 2022

Corrosion can affect the reliability of materials, which has attracted the attention of the industry. Corrosion detection and quantitative analysis are particularly important for scientific management and decision-making. In this paper, the imaging method based ultrasonic guided wave (UGW) detection technology and fully connected neural network (FCNN) is proposed to realize real-time imaging of corrosion damages. The imaging method contains offline training and online testing. Offline training aims to establish the relationship between detection signals and velocity maps and it is accelerated by adaptive moment estimation (Adam) algorithm. In the process of online testing, the trained model can be called directly to realize real-time imaging, that is, the detection signals are fed into the model and the network will predict the velocity maps. Finally, the velocity maps are converted to thickness maps according to the dispersion curves. Numerical experimental results show that the mean square errors (mses) are respectively 9.08 × 10−4, 2.47 × 10−3 and 2.59 × 10−3 in training, validation and testing. Compared with irregular corrosion damages, the imaging method has better imaging quality for circular corrosion damages.
A Comparison Study of Several Ultrasonic Endoscopy Technology for Tubes’ Inspection
Authors: Xi Ze , Wang Xiangang , Luo Xiaowei
Published: January 2022

Ultrasonic technology has developed rapidly in decades. However, few ultrasonic technologies have been proposed for tubes’ internal inspection. In this paper, 6 types of ultrasonic endoscopic transducers are brought to detect volumetric and planar flaws in tubes. Steam generator tube is application target. Beam simulations are implemented and compared using an open source acoustic simulation toolbox to illustrate beneficial effects of the different transducers. The results show the proposed endoscopic array transducers can form focused ultrasonic beams in tube wall, which do helps when detecting complex defects, such as crevice with uncertain direction. A prototype circular array transducer with 64 elements is fabricated to demonstrate the design. A straight tube (Φ19 × 3mm) made of carbon-steel with 8 longitudinal grooves and 8 ring grooves of no more than 0.5mm width on both inner and outer tube wall are applied in endoscopy experiments. The results demonstrate the detection sensitivity of the circular array transducer reaches 0.2mm in both circumferential direction and axial direction. The combination of the above proposed transducers and advanced imaging algorithms such as total focusing method may build an integrated array ultrasonic endoscopic inspection scheme for the internal inspection of tubes.
Results of a Virtual Round Robin Study to Estimate Probability of Detection for Dissimilar Metal Welds
Authors: Meyer Ryan M. , Holmes Aimee E. , Morales Romarie , Virkkunen Iikka , Seuaciuc-Osorio Thiago , Lin Bruce
Published: January 2022

This paper presents efforts to overcome challenges with empirical probability of detection (POD) estimations in the nuclear power industry through the utilization of a novel virtual flaw method. A virtual round robin (VRR) study was conducted under the Program for Investigation Of NDE by International Collaboration (PIONIC), organized by the United States Nuclear Regulatory Commission (NRC) utilizing data generated by the virtual flaw method. Analysis of results from the VRR was performed by teams from Pacific Northwest National Laboratory (PNNL), Electric Power Research Institute (EPRI), and Aalto University.

Empirically derived POD estimations are presented, and challenges associated with obtaining these estimations are discussed. The virtual flaw method is introduced and some details of its implementation for the VRR activity are described. Results from POD analysis of the VRR data by PNNL, EPRI, and Aalto University are presented and a discussion regarding differences in analysis results is provided. Finally, potential future efforts to improve the application of the virtual flaw method and its estimation of POD are discussed.
Online Monitoring of Electric Power Box Using Waveguide Sensors
Authors: Fultariya Jaykumar , Raja Nishanth , Balasubramaniam Krishnan
Published: January 2022

Majority of the industrial and domestic fire accidents occur due to electric short circuits. Hence, it is imperative to monitor the condition of electric power box to facilitate preventive maintenance. The key reasons for power box failure are overheating, tripping, and arcing/sparking at the electric joints. This paper reports on the online condition monitoring of electric power box using the waveguide sensing technology. The critical components of the power box are monitored, namely; Miniature Circuit Breaker (MCB), Solid State Relay (SSR), and Contactor. A pair of wire waveguides is designed to monitor overheating as well as the occurrence of tripping in the MCB. While one waveguide functions as an active ultrasound temperature sensor, the other acts as a passive acoustic emission based arcing sensor. During the overheating experiments, the ultrasound sensor precisely measures the temperature gradient along multiple points on the sub-components, with a minimum gauge length of 10–15mm. The perturbation caused due to MCB tripping is successfully captured by the passive acoustic emission sensor and the location of tripping is determined. Both the overheating temperature and tripping signature are detected by the waveguide transducer system. This work has potential application in industrial and commercial establishments to ensure improved reliability and workplace safety.
Vibration Analysis for NDE of Ceramic Components
Authors: Köhler Bernd , Tschöke Kilian , Stephan Mareike , Gartsev Sergey , Barth Martin
Published: January 2022

In this contribution we study vibration testing for ceramic parts on the example of an electrolyte cup, used in a prospective power cells design. An adapted experimental arrangement for the vibration excitation and the acoustic measurements was built and tested. In parallel, extensive numerical modal analysis simulations were performed using ANSYS. The resonance spectra obtained by modelling agree with the experimentally determined spectra in such a way that the experimentally determined eigenfrequencies can be assigned to the cup modes. The correctness of this identification was verified by direct mode visualization with scanning laser doppler vibrometry.

A much faster and potentially in-line capable method for experimental mode identification is the simultaneous measurement at several points using a microphone array and subsequent signal evaluation with operational modal analysis. This procedure was successfully tested. Features in the spectra connected with the presence of flaws are discussed. These features include the drop of some eigenfrequencies and the splitting of degenerated modes.
Structural Health Monitoring of Electro-Mechanical Actuators in Aviation: Recent Breakthroughs and Further Challenges
Authors: Memmolo Vittorio , Vaselli Carmine , Cimminiello Nicola , Salvato Pasquale , Monaco Ernesto , Ricci Fabrizio
Published: January 2022

Electrical actuation systems have recently been introduced in aviation pursuing the concepts of More Electric Aircraft. Instead of employing hydraulic pipelines, Electro-Mechanical Actuator (EMA) transfers the power by “wires” with a consequent improvement of the aircraft actuation performance. However, the integration of linear electromechanical actuators is promising yet challenging in safety critical systems. Within this context, this work critically reviews electromechanical actuators currently available for aerospace application, the limits for their upcoming deployment and the different solutions to achieve an on-condition maintenance to reduce any safety risk during lifetime. First of all, the typical conversion mechanism adopted so far are briefly described with emphasis on the most suited for aerospace applications. A further insight is given to failure modes of these systems, which dramatically contrast the countless inherent advantages thereof. A particular attention is given to the jamming of the driven load, which is a critical mechanical transmission failure in many applications such as primary flight controls or landing gears extension and steering. Finally, the focus is moved to possible strategies to avoid any hazard induced by this failure. In particular, any structural alteration which is prone to induce jamming can be monitored towards the establishment of a predictive maintenance. Different possibilities are available in the way to timely assess the bearing of inner EMA surfaces where screwing is enabled.
Accurate Thickness Inversion of Corrosion Using A1 Lamb Wave
Authors: Lin Min , Liu Yang
Published: January 2022

Corrosion is one of the most critical issues in the oil and gas industry, leading to severe environmental and economic problems. Due to the high cost and serious safety risk of corrosion, it is essential to improve current corrosion testing techniques to detect corrosion damages at an early stage. Guided wave tomography (GWT) demonstrates its great potential to inspect and quantify the corrosion damage. GWT is capable of determining the residual life of corrosion structures by quantifying the remaining wall thickness. In this paper, an accurate guided wave tomography technique incorporating full waveform inversion (FWI) and higher-order Lamb waves (A1 mode) is presented for plate-like structures, which is able to get high-resolution reconstruction results. The technique consists of three steps: forward modeling, velocity inversion and thickness reconstruction. The forward modeling is computed by solving the elastic full-wave equations in 2-D time domain by using the finite difference method. High-resolution phase velocity inversion can then be obtained by minimizing the waveform misfit function between simulated and recorded data using a second order optimization method, which updates the velocity model from low to high frequencies iteratively. Finally, the velocity variations can be transformed into depth profiles by using the dispersive characteristics of ultrasonic guided waves; therefore, the thickness reconstruction can be obtained. The numerical simulations are performed on an aluminum plate with a complicated corrosion defect. By comparing the thickness reconstruction maps using both A1 and A0 modes, the results demonstrate that FWI with A1 mode can achieve significantly better resolution of corrosion imaging than that with A0 mode.
FEM Simulation of Waves Excited by Array Probe Propagating in Centrifugally Cast Stainless Steel With Hexagonal Column
Authors: Lin Shan , Ikegami Yasushi
Published: January 2022

Centrifugally cast stainless steel (CCSS) is widely used in PWR primary coolant systems. However, ultrasonic testing for such material is very challenging because its coarse grains and anisotropic property. The phased array ultrasonic technology (PAUT) is considered the most promising solution to the problem mentioned. To improve the accuracy of PAUT for CCSS with columnar grains, we used the voxel-based finite element method to perform simulation of wave propagation in CCSS, where waves were excited by a linear array. We modeled columnar grains in CCSS with hexagonal columns and introduced a side-drilled hole. It was easily to have different inclined columnar grains by rotating the crystal axes. All column crystals were considered cubic crystals while CCSS with columnar grains was macroscopically transversely isotropic. Wave propagations were computed for different focal laws and their results were compared. Waves exactly propagated toward and focused at the targeted SDH when focal laws were calculated according to the anisotropic property of CCSS, but deviated the target for focal laws based on isotropy.
Benefit of Neural Network for the Optimization of Defect Detection on Composite Material Using Ultrasonic Non Destructive Testing
Authors: Trouvé-Peloux P. , Abeloos B. , Ben Fekih A. , Trottier C. , Roche J.-M.
Published: January 2022

This paper is dedicated to out-of-plane waviness defect detection within composite materials by ultrasonic testing. We present here an in-house experimental database of ultrasonic data built on composite pieces with/without elaborated defects. Using this dataset, we have developed several defect detection methods using the C-scan representation, where the defect is clearly observable. We compare here the defect detection performance of unsupervised, classical machine learning methods and deep learning approaches. In particular, we have investigated the use of semantic segmentation networks that provides a classification of the data at the “pixel level”, hence at each C-scan measure. This technique is used to classify if a defect is detected, and to produce a precise localization of the defect within the material. The results we obtained with the various detection methods are compared, and we discuss the drawbacks and advantages of each method.
Large anomalous Nernst effect and nodal plane in an iron-based kagome ferromagnet
Authors: Chen Taishi , Minami Susumu , Sakai Akito , Wang Yangming , Feng Zili , Nomoto Takuya , Hirayama Motoaki , Ishii Rieko , Koretsune Takashi , Arita Ryotaro , Nakatsuji Satoru
Published: January 2022

Kagome ferromagnet Fe
3
Sn exhibits large magnetic thermoelectric effect due to Berry curvature enhanced by a nodal plane.
How can same-gene mutations promote both cancer and developmental disorders?
Authors: Nussinov Ruth , Tsai Chung-Jung , Jang Hyunbum
Published: January 2022

This review offers why same-gene mutations can lead to cancer and neurodevelopmental disorders and why a high risk of cancer.
Inclusion in human–machine interactions
Authors: Reid Tahira , Gibert James
Published: January 2022

Human–machine interactions research should include diverse subjects and benefit all people
Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis
Authors: Bjornevik Kjetil , Cortese Marianna , Healy Brian C. , Kuhle Jens , Mina Michael J. , Leng Yumei , Elledge Stephen J. , Niebuhr David W. , Scher Ann I. , Munger Kassandra L. , Ascherio Alberto
Published: January 2022

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system of unknown etiology. We tested the hypothesis that MS is caused by Epstein-Barr virus (EBV) in a cohort comprising more than 10 million young adults on active duty in the US military, 955 of whom were diagnosed with MS during their period of service. Risk of MS increased 32-fold after infection with EBV but was not increased after infection with other viruses, including the similarly transmitted cytomegalovirus. Serum levels of neurofilament light chain, a biomarker of neuroaxonal degeneration, increased only after EBV seroconversion. These findings cannot be explained by any known risk factor for MS and suggest EBV as the leading cause of MS.
Epstein-Barr virus and multiple sclerosis
Authors: Robinson William H. , Steinman Lawrence
Published: January 2022

Infection with Epstein-Barr virus is the trigger for the development of multiple sclerosis
Does recruitment trigger negative density-dependent feedback loops in stream-dwelling salmonids?
Authors: Lobón-Cerviá Javier
Published: January 2022

I explored the hypothesis that recruitment may stabilize the numerical dynamics of stream-dwelling salmonids by triggering density-dependent feedback loops through the operation of recruitment dependence on individual growth, mortality, life span and maximum size and their effects on fecundity. I examined 98 cohorts of two Salmo trutta populations of northern Spain and a population of Jutland (Denmark) located 2400 km apart. Recruitment, growth, mortality, life span and maximum size were inter-related, were recruitment-dependent and described negative power trajectories. In the Spanish populations, faster-growing individuals of weakly recruited cohorts with lower mortality attain longer life span and larger size. Hence, larger females spawning more abundant, larger eggs that, in turn, induce stronger cohorts of higher spawners’ abundance, recruitment and mortality. The mortality patterns match the self-thinning patterns, an ultimate expression of competition. Significant relationships among self-thinning slopes and mortalities rates with increasing recruitment demonstrate that the rate at which density-driven mortality is higher, the stronger the intensity of intraspecific competition. Space-limited habitat and size-dependent resource availability underpinning site-specific carrying capacities suggest that interference competition is the primary mechanism underpinning population regulation.
Radial growth decline of white spruce (Picea glauca) during hot summers without drought: preliminary results from a study site south of a boreal forest border
Authors: Lapenis Andrei , Robinson George , Lawrence Gregory
Published: January 2022

If the modern climate trend continues for an additional 20–40 years, forests along the southern border of Canadian taiga may shift into new ranges of annual temperature and precipitation that are similar to the modern climate of central New York State, United States. Here we investigate the possible future response of white spruce (Picea glauca (Moench) Voss) to a warmer climate by studying trees planted 90 years ago near the southern limit of their climate tolerance in central New York, 300 km south of the boreal forest where this species is prevalent. We employed high-frequency recording dendrometers to determine radial growth phenology of six mature white spruce trees during 2013–2017. The results demonstrate significant reductions in the length of radial growth periods inversely proportional to the number of hot days with air temperature exceeding 30 °C. During years with very hot summers, the start of radial growth began about 3 days earlier than the 2013–2017 average. However, in those same years, the end of radial growth was also about 17 days earlier resulting in a shorter (70 days versus 100 days) radial growth season. Abundant (350–500 mm) summer precipitation, which resulted in soil moisture values of 20%–30%, allowed us to dismiss drought as a factor. Instead, a likely cause of reduced radial growth was mean temperature that exceeded optimal growth ranges, exacerbated by temperature extremes in ranges that lead to photoinhibition. The latter case was evident in the two warmest growing seasons (2013 and 2017), marked by extended periods of high daytime temperature (>30 °C) followed by early cessation of radial growth independent of seasonal precipitation.
Synchronized movement between US lumber futures and southern pine sawtimber prices and COVID-19 impacts
Authors: Gan Jianbang , Tian Nana , Choi Junyeong , Pelkki Matthew H.
Published: January 2022

We analyzed the synchronized movements of lumber futures and southern pine sawtimber stumpage prices in the United States since 2011 and their response to COVID-19 events using wavelet analysis and event study. We found that the sawtimber and lumber prices have followed complex comovement patterns in the time–frequency domain and both reacted to COVID-19 events with a higher response intensity of the lumber price. Although they reacted differently to the early COVID-19 episodes and vaccine news, the sawtimber and lumber prices responded similarly to the COVID-19 pandemic declarations by the World Health Organization and US president, the US Food and Drug Administration panel’s recommendation of the first COVID-19 vaccine, and economic stimulus legislation. The patterns of synchronized movements between the sawtimber and lumber prices varied with time and frequency, but their comovement at low frequencies (>64 weeks) has strengthened since 2014 and been led by the lumber futures price; COVID-19 episodes have not changed this trend. The different magnitude of response of the two prices to the COVID-19-related events, as well as the long-term dominance of the lumber price in the comovement, reveals asymmetric price negotiation power and benefit distributions among the agents of the lumber value chain.
It's Good to Talk: A Comparison of Using Voice Versus Screen-Based Interactions for Agent-Assisted Tasks
Authors: Reicherts Leon , Rogers Yvonne , Capra Licia , Wood Ethan , Duong Tu Dinh , Sebire Neil
Published: January 2022

Voice assistants have become hugely popular in the home as domestic and entertainment devices. Recently, there has been a move towards developing them for work settings. For example,Alexa for BusinessandIBM Watsonfor Businesswere designed to improve productivity, by assisting with various tasks, such as scheduling meetings and taking minutes. However, this kind of assistance is largely limited to planning and managing user's work. How might they be developed to do more by way of empowering people at work? Our research is concerned with achieving this by developing an agent with the role of a facilitator that assists users during an ongoing task. Specifically, we were interested in whether the modality in which the agent interacts with users makes a difference: How does a voice versus screen-based agent interaction affect user behavior? We hypothesized that voice would be more immediate and emotive, resulting in more fluid conversations and interactions. Here, we describe a user study that compared the benefits of using voice versus screen-based interactions when interacting with a system incorporating an agent, involving pairs of participants doing an exploratory data analysis task that required them to make sense of a series of data visualizations. The findings from the study show marked differences between the two conditions, with voice resulting in more turn-taking in discussions, questions asked, more interactions with the system and a tendency towards more immediate, faster-paced discussions following agent prompts. We discuss the possible reasons for why talking and being prompted by a voice assistant may be preferable and more effective at mediating human-human conversations and we translate some of the key insights of this research into design implications.
Enhancing the Quantum Linear Systems Algorithm Using Richardson Extrapolation
Authors: Vazquez Almudena Carrera , Hiptmair Ralf , Woerner Stefan
Published: January 2022

We present a quantum algorithm to solve systems of linear equations of the form
Ax
=
b
, where
A
is a tridiagonal Toeplitz matrix and
b
results from discretizing an analytic function, with a circuit complexity of
O
(1/√ε, poly (log κ, log
N
)), where
N
denotes the number of equations, ε is the accuracy, and κ the condition number. The
repeat-until-success
algorithm has to be run
O
(κ/(1-ε)) times to succeed, leveraging amplitude amplification, and needs to be sampled
O
(1/ε
2
) times. Thus, the algorithm achieves an exponential improvement with respect to
N
over classical methods. In particular, we present efficient oracles for state preparation, Hamiltonian simulation, and a set of observables together with the corresponding error and complexity analyses. As the main result of this work, we show how to use Richardson extrapolation to enhance Hamiltonian simulation, resulting in an implementation of Quantum Phase Estimation (QPE) within the algorithm with 1/√ε circuits that can be run in parallel each with circuit complexity 1/√ ε instead of 1/ε. Furthermore, we analyze necessary conditions for the overall algorithm to achieve an exponential speedup compared to classical methods. Our approach is not limited to the considered setting and can be applied to more general problems where Hamiltonian simulation is approximated via product formulae, although our theoretical results would need to be extended accordingly. All the procedures presented are implemented with Qiskit and tested for small systems using classical simulation as well as using real quantum devices available through the IBM Quantum Experience.
Editorial Introduction - GROUP 2022 Second Wave
Authors: Baumer Eric P. S. , Holten Møller Naja L. , de Souza Cleidson R. B. , Fiesler Casey , Pinatti de Carvalho Aparecido Fabiano , França Juliana Baptista dos Santos , Menendez-Blanco Maria
Published: January 2022

For over a quarter century, GROUP has offered a premier yet intimate and welcoming venue for agenda-setting, diverse research. Although the traditional focus of the conference is on supporting group work, it has expanded to include research from computer-supported cooperative work, sociotechnical studies, practice-centered computing, human-computer interaction, computersupported collaborative learning, participatory technology design, and other related areas. The work presented in this issue embodies that interdisciplinary ethos. Papers in this issue cover a wide range topics, from human-AI collaboration, to collaboration in virtual reality, to perceptions of privacy and security, to the myriad impacts of the COVID-19 pandemic. The application domains are similarly wide ranging, from health data, to civic engagement, to educational settings, to government provision of social services. Similar to the 2021 issue, this issue also continues the tradition of design fiction at GROUP. This issue of PACM:HCI brings you papers from the planned 2022 ACMConference on Supporting Group Work (GROUP 2022). Typically, the GROUP conference occurs every two years. However, research developments do not necessarily follow conference deadline cycles. Thus, the GROUP conference offers authors the opportunity to submit to multiple waves. The first wave of papers for this conference were published in July 2021 in Volume 5 of PACM:HCI, and papers from this current issue were first submitted in May 2021. Both of these sets of papers published as part of the planned GROUP 2022 conference were authored and reviewed during the COVID-19 pandemic. These papers represent commendable volumes of hard work and resilience, not just from the authors, but also from the reviewers, the program committee, and the conference organizers. Additionally, the pandemic forced a major change to the conference at which these papers will be presented.
Twitch Users' Motivations and Practices During Community Mental Health Discussions
Authors: Uttarapong Jirassaya , LaMastra Nina , Gandhi Reesha , Lee Yu-hao , Yuan Chien Wen (Tina) , Wohn Donghee Yvette
Published: January 2022

Live streaming is a form of media that allows streamers to directly interact with their audience. Previous research has explored mental health, Twitch.tv and live streaming platforms, and users' social motivations behind watching live streams separately. However, few have explored how these all intertwine in conversations involving intimate, self-disclosing topics, such as mental health. Live streams are unique in that they are largely masspersonal in nature; streamers broadcast themselves to mostly unknown viewers, but may choose to interact with them in a personal way. This study aims to understand users' motivations, preferences, and habits behind participating in mental health discussions on live streams. We interviewed 25 Twitch viewers about the streamers they watch, how they interact in mental health discussions, and how they believe streamers should discuss mental health on live streams. Our findings are contextualized in the dynamics in which these discussions occur. Overall, we found that the innate design of the Twitch platform promotes a user-hierarchy in the ecosystem of streamers and their communities, which may affect how mental health is discussed.
Auditing Risk Prediction of Long-Term Unemployment
Authors: Seidelin Cathrine , Moreau Therese , Shklovski Irina , Holten Møller Naja
Published: January 2022

As more and more governments adopt algorithms to support bureaucratic decision-making processes, it becomes urgent to address issues of responsible use and accountability. We examine a contested public service algorithm used in Danish job placement for assessing an individual's risk of long-term unemployment. The study takes inspiration from cooperative audits and was carried out in dialogue with the Danish unemployment services agency. Our audit investigated the practical implementation of algorithms. We find (1) a divergence between the formal documentation and the model tuning code, (2) that the algorithmic model relies on subjectivity, namely the variable which focus on the individual's self-assessment of how long it will take before they get a job, (3) that the algorithm uses the variable "origin" to determine its predictions, and (4) that the documentation neglects to consider the implications of using variables indicating personal characteristics when predicting employment outcomes. We discuss the benefits and limitations of cooperative audits in a public sector context. We specifically focus on the importance of collaboration across different public actors when investigating the use of algorithms in the algorithmic society.
Alerts as Coordination Mechanisms
Authors: Mastrianni Angela , Almengor Lynn , Sarcevic Aleksandra
Published: January 2022

In this study, we explore how clinical decision support features can be designed to aid teams in caring for patients during time-critical medical emergencies. We interviewed 12 clinicians with experience in leading pediatric trauma resuscitations to elicit design requirements for decision support alerts and how these alerts should be designed for teams with shared leadership. Based on the interview data, we identified three types of decision support alerts: reminders to perform tasks, alerts to changes in patient status, and suggestions for interventions. We also found that clinicians perceived alerts in this setting as coordination mechanisms and that some alert preferences were associated with leader experience levels. From these findings, we contribute three perspectives on how alerts can aid coordination and discuss implications for designing decision support alerts for shared leadership in time-critical medical processes.
Situated Scaffolding for Sustainable Participatory Design
Authors: Cerna Katerina , Müller Claudia , Randall Dave , Hunker Martin
Published: January 2022

An extensive literature on participatory design with older adults has, thus far, little to say about the support older adults need when involved in online activities. Our research suggests that to empower older adults in participatory design, scaffolding work has to be done. Scaffolding interactions - creating temporary instructional support to help the learning of participants - is a common approach in participatory design. Yet, when applied in online participatory design with older adults, the traditional understanding of the concept does not match the way older adults' learn. Hence, we argue for a new understanding of this term, which we call situated scaffolding. We illustrate our argument with a case where older adults collaborate online as part of a participatory design project. We unpack the different dimensions of situated scaffolding and discuss how this novel understanding can be used to further inform sustainable participatory design for and with older adults.
Access Under Duress
Authors: Fan Bonnie , Fox Sarah E.
Published: January 2022

This paper examines the rapid turn to remote public meetings during the COVID-19 pandemic. Drawing on a mix of archival materials, participant observation, and interviews within and around two mid- to large cities in the Rust Belt and Midwest regions of the United States, we consider how public officials introduced digital meeting platforms and surveys in place of traditional forms of in-person public consultation. We also examine emergent strategies of residents as they worked to have their voices heard and concerns met during a time of compounding crises (e.g., pandemic, economic recession, racial violence). Drawing from this case study, we articulate the concept of disruptive testimony, forms of public witnessing that trouble established hierarchies of power, surface conflict, and open opportunities for social change. We argue consideration for collective counter-power is increasingly important to GROUP scholarship as it attends to civic engagement beyond participation in formal, sanctioned government processes.
Topophilia, Placemaking, and Boundary Work
Authors: Cho Janghee , Beck Samuel , Voida Stephen
Published: January 2022

The COVID-19 pandemic fundamentally changed the nature of work by shifting most in-person work to a predominantly remote modality as a way to limit the spread of the coronavirus. In the process, the shift to working-from-home rapidly forced the large-scale adoption of groupware technologies. Although prior empirical research examined the experience of working-from-home within small-scale groups and for targeted kinds of work, the pandemic provides HCI and CSCW researchers with an unprecedented opportunity to understand the psycho-social impacts of a universally mandated work-from-home experience rather than an autonomously chosen one. Drawing on boundary theory and a methodological approach grounded in humanistic geography, we conducted a qualitative analysis of Reddit data drawn from two work-from-home-related subreddits between March 2020 and January 2021. In this paper, we present a characterization of the challenges and solutions discussed within these online communities for adapting work to a hybrid or fully remote modality, managing reconfigured work-life boundaries, and reconstructing the home's sense of place to serve multiple, sometimes conflicting roles. We discuss how these findings suggest an emergent interplay among adapted work practice, reimagined physical (and virtual) spaces, and the establishment and continual re-negotiation of boundaries as a means for anticipating the long-term impact of COVID on future conceptualizations of productivity and work.
"That's Something for Children"
Authors: Paluch Richard , Müller Claudia
Published: January 2022

Robotic systems are increasingly seen as possible technical aids against the background of demographic change and the associated pressures on care systems, with increasing numbers of care recipients and a decreasing number of trained caregivers. In human-computer interaction and computer-supported cooperative work, different design paradigms are currently being pursued to explore which features and appearances are favorable for meaningful interactions of humans with robotic systems. One such approach, labeled as "otherware", proposes to conceptualize robots beyond a naive anthropomorphism or zoomorphism, rather developing the idea of a figure that goes beyond the dichotomy between "being alive" and "being a technical artefact". We present an ethnographic study on the perceptions, attitudes, and practices of care attendants and nursing-home residents in their experimenting with off-the-shelf robotic cats and dogs. The three-week study shows specific appropriation practices of the robotic pets, and how the care attendants - partly together with the residents - define their experiences of the robotic pets, i.e., in which situations the robotic pets are considered either as living beings or as technology toys. The study provides practice-based insights into how possible uses of robotic pets could be meaningfully integrated into care practices, but also which ethical reflections were discussed during their use. Finally, this ethnographic study functioned as a collaborative learning process between researchers, care attendants, and residents, and thus also points out possible aspects that arose with regard to future learning spaces of professional and organizational development for dealing with innovative technologies in residential care contexts.
Kiro
Authors: Ringfort-Felner Ronda , Laschke Matthias , Sadeghian Shadan , Hassenzahl Marc
Published: January 2022

Soon, voice assistants might be able to engage in fully-fledged social conversations with people, rather than merely providing a voice-operated interface to functionality and data. So far, not much is known about designing such "social" voice assistants and the potential social experiences, which could and should emerge in everyday situations. In the present paper, we created a design fiction to explore a sophisticated social voice assistant in the context of the car. Based on models from psychology and psychotherapy, we designed the fictional "virtual passenger" Kiro. We created a website for Kiro (http://www.heykiro.com/), distributed it, and collected responses in various ways (e.g., comments). We further ran a market research-type focus group. In general, we found people to accept Kiro as a conversation partner but not as a replacement for human-human conversations. We suggest designing social voice assistants in a way to enable novel types of socially fulfilling, yet distinct human-machine conversations.
Studying Up Machine Learning Data
Authors: Miceli Milagros , Posada Julian , Yang Tianling
Published: January 2022

Research in machine learning (ML) has argued that models trained on incomplete or biased datasets can lead to discriminatory outputs. In this commentary, we propose moving the research focus beyond bias-oriented framings by adopting a power-aware perspective to "study up" ML datasets. This means accounting for historical inequities, labor conditions, and epistemological standpoints inscribed in data. We draw on HCI and CSCW work to support our argument, critically analyze previous research, and point at two co-existing lines of work within our research community \,---\,one bias-centered, the other power-aware. We highlight the need for dialogue and cooperation in three areas: data quality, data work, and data documentation. In the first area, we argue that reducing societal problems to "bias" misses the context-based nature of data. In the second one, we highlight the corporate forces and market imperatives involved in the labor of data workers that subsequently shape ML datasets. Finally, we propose expanding current transparency-oriented efforts in dataset documentation to reflect the social contexts of data design and production.