Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Selective Exposure to Berita Harian Online and Utusan Malaysia Online: The Roles of Surveillance Motivation, Website Usability and Website Attractiveness

News media allows audiences to be selective in determining both their news sources and type of news stories they read. This study examined factors influencing selective exposure to the online editions of two mainstream Malaysian newspapers, Berita Harian and Utusan Malaysia. Using selective exposure theory as the theoretical lens, this study compared both newspapers in terms of their audiences’ level of surveillance motivation, and how audiences rate the newspapers’ websites with respect to usability and attractiveness. This study used a within-subject experimental research design that exposed 51 subjects to both Berita Harian and Utusan Malaysia online newspapers. The results of the experiment indicate that Berita Harian and Utusan Malaysia online were significantly different in terms of website usability; however, no significant differences were found in terms of surveillance motivation or website attractiveness between the two newspapers. Further analysis indicate that the only significant predictor of selective exposure was website usability. This study highlights the importance of website usability for online newspapers wanting to harness audience selectivity

Protocol for a partially nested randomised controlled trial to evaluate the effectiveness of the scleroderma patient-centered intervention network COVID-19 home-isolation activities together (SPIN-CHAT) program to reduce anxiety among at-risk scleroderma patients

Objective: Contagious disease outbreaks and related restrictions can lead to negative psychological outcomes, particularly in vulnerable populations at risk due to pre-existing medical conditions. No randomised controlled trials (RCTs) have tested interventions to reduce mental health consequences of contagious disease outbreaks. The primary objective of the Scleroderma Patient-centered Intervention Network COVID-19 Home-isolation Activities Together (SPIN-CHAT) Trial is to evaluate the effect of a videoconference-based program on symptoms of anxiety. Secondary objectives include evaluating effects on symptoms of depression, stress, loneliness, boredom, physical activity, and social interaction.Methods: The SPIN-CHAT Trial is a pragmatic RCT that will be conducted using the SPIN-COVID-19 Cohort, a sub-cohort of the SPIN Cohort. Eligible participants will be SPIN-COVID-19 Cohort participants without a positive COVID-19 test, with at least mild anxiety (PROMIS Anxiety 4a v1.0 T-score >= 55), not working from home, and not receiving current counselling or psychotherapy. We will randomly assign 162 participants to intervention groups of 7 to 10 participants each or waitlist control. We will use a partially nested RCT design to reflect dependence between individuals in training groups but not in the waitlist control. The SPIN-CHAT Program includes activity engagement, education on strategies to support mental health, and mutual participant support. Intervention participants will receive the 4-week (3 sessions per week) SPIN-CHAT Program via video-conference. The primary outcome is PROMIS Anxiety 4a score immediately post-intervention.Ethics and dissemination: The SPIN-CHAT Trial will test whether a brief videoconference-based intervention will improve mental health outcomes among at-risk individuals during contagious disease outbreak

PSH: A private and shared history-based incentive mechanism

Fully decentralized peer-to-peer (P2P) systems do not have a central control mechanism. Thus, different forms of control mechanisms are required to deal with selfish peers. One type of selfish behavior is the consumption of resources without providing sufficient resources. Therefore, incentive schemes encourage peers to share resources while punishing selfish peers. A well-known example of an incentive scheme is Tit-for-Tat (TFT), as used in BitTorrent. With this scheme, a peer can only consume as much resources as it provides. TFT is resilient to collusion due to relying on private histories only. However, TFT can only be applied to peers with direct reciprocity. This paper presents a private and shared history (PSH) based incentive mechanism, which supports transitive relations (indirect reciprocity). Furthermore, it is resilient to collusion and it combines private and shared histories in an efficient manner. The PSH approach uses a shared history for identifying transitive relations. Those relations are verified using private histories. Simulations show that the PSH mechanism has a higher transaction success ratio than TFT

Factors associated with patient-reported likelihood of using online self-care interventions: A Scleroderma Patient-centered Intervention Network (SPIN) cohort study

Contains fulltext : 212377.pdf (publisher's version ) (Open Access)Objectives: The Scleroderma Patient-centered Intervention Network (SPIN) Cohort uses the cohort multiple randomised controlled trial design to embed trials of online self-care interventions for people living with systemic sclerosis (SSc; scleroderma). To offer interventions to patients interested in using them, participants complete signalling items that query about the likelihood that patients would agree to participate in nine different hypothetical online programmes addressing common SSc-related problems. It is not known what factors influence patient-reported interest in participating in a particular online intervention and if intervention-specific signalling questions provide unique information or replicate broader characteristics, such as overall willingness to participate or self-efficacy. This study assessed factors that explain responses to intervention-specific signalling items. Design: Cross-sectional survey. Setting: SPIN Cohort participants enrolled at 42 centres from Canada, the USA, the UK, France, Spain and Mexico who completed study questionnaires from March 2014 to January 2018 were included. Measures: Demographic and disease characteristics, self-efficacy and symptoms related to each specific intervention were completed in addition to signalling items. General likelihood of using interventions was calculating by taking the mean score of the remaining signalling questions. Participants: 1060 participants with complete baseline data were included in the analyses. Results: For all individual signalling questions, controlling for other variables, the mean of the remaining signalling questions was the strongest predictor (standardised regression coefficient ß from 0.61 (sleep) to 0.80 (self-management)). Smaller, but statistically significant, associations were found with the symptom associated with the respective signalling question and with general self-efficacy for 7 of 9 signalling questions. Conclusions: The main factor associated with patients' interest in participating in a disease-specific online self-care intervention is their general interest in participating in online interventions. Factors that may influence this general interest should be explored and taken into consideration when inviting patients to try online interventions.9 p

Factors influencing patient interest in participating in an online self-care intervention: A Scleroderma Patient-centered Intervention Network (SPIN) Cohort Study

Contains fulltext : 219623.pdf (Publisher’s version ) (Open Access)2 p

Informant: Detecting Sybils Using Incentives

Abstract. We propose an economic approach to Sybil attack detection. In our Informant protocol, a detective offers a reward for Sybils to reveal themselves. The detective accepts from one identity a security deposit and the name of target peer; the deposit and a reward are given to the target. We prove the optimal strategy for the informant is to play the game if and only if she is Sybil with a low opportunity cost, and the target will cooperate if and only if she is identical to the informant. Informant uses a Dutch auction to find the minimum possible reward that will reveal a Sybil attacker. Because our approach is economic, it is not limited to a specific application and does not rely on a physical device or token.

Informant: Detecting Sybils using incentives

Abstract. We propose an economic approach to Sybil attack detection. In our Informant protocol, a detective offers a reward for Sybils to reveal themselves. The detective accepts from one identity a security deposit and the name of target peer; the deposit and a reward are given to the target. We prove the optimal strategy for the informant is to play the game if and only if she is Sybil with a low opportunity cost, and the target will cooperate if and only if she is identical to the informant. Informant uses a Dutch auction to find the minimum possible reward that will reveal a Sybil attacker. Because our approach is economic, it is not limited to a specific application and does not rely on a physical device or token.