Tracking a table tennis ball for umpiring purposes using a multi-agent system

Tracking a table tennis ball for umpiring purposes is a challenging task as, in real-match scenarios, the ball travels fast and can become occluded or merged with other background objects. This paper presents the design of a multi-view based tracking system that can overcome the challenges of tracking a ball in real match sequences. The system has been tested on a complete table tennis rally and the results are very promising. The system is able to continuously track the ball with only marginal variations in detection. Furthermore, the initialization of the multi-camera system means it is both a portable and cost-effective solution for umpiring purposes

Tracking a table tennis ball for umpiring purposes

This study investigates tracking a table-tennis ball rapidly from video captured using low-cost equipment for umpiring purposes. A number of highly efficient algorithms have been developed for this purpose. The proposed system was tested using sequences capture from real match scenes. The preliminary results of experiments show that accurate and rapid tracking can be achieved even under challenging conditions, including occlusion and colour merging. This work can contribute to the development of an automatic umpiring system and also has the potential to provide amateur users open access to a detection tool for fast-moving, small, round objects

Developmental Aspects of Schizotypy and Suspiciousness: a Review.

PURPOSE OF THE REVIEW: This review identifies the early developmental processes that contribute to schizotypy and suspiciousness in adolescence and adulthood. It includes the most recent literature on these phenomena in childhood. RECENT FINDINGS: The early developmental processes that affect schizotypy and paranoia in later life are complex. In contrast to existing studies of psychiatric patients and clinical/nonclinical adult populations, the study of schizotypy and suspiciousness in young children and adolescents is possible due to new child-appropriate dimensional assessments. New assessments and the advancement of technology (e.g., virtual reality in mental health) as well as statistical modeling (e.g., mediation and latent-class analyses) in large data have helped identified the developmental aspects (e.g., psychosocial, neurocognitive and brain factors, nutrition, and childhood correlates) that predict schizotypy and suspiciousness in later life. SUMMARY: Prospective longitudinal designs in community youths can enhance our understanding of the etiology of schizophrenia-spectrum disorders and, in the future, the development of preventive interventions by extending adult theories and interventions to younger populations.Betty Behrens Research Fellowship, Clare Hall, University of Cambridg

Ultraviolet avalanche in anisotropic non-Abelian plasmas

We present solutions of coupled particle-field evolution in classical U(1) and SU(2) gauge theories in real time on three-dimensional lattices. For strongly anisotropic particle momentum distributions, we find qualitatively different behavior for the two theories when the field strength is high enough that non-Abelian self-interactions matter for SU(2). It appears that the energy drained by a Weibel-like plasma instability from the particles does not build up exponentially in transverse magnetic fields but instead returns, isotropically, to the hard scale via a rapid avalanche into the ultraviolet.Comment: 22 pages, 10 figures; v3: small textual changes; updated to correspond with version to appear in publicatio

Beyond Counting: New Perspectives on the Active IPv4 Address Space

In this study, we report on techniques and analyses that enable us to capture Internet-wide activity at individual IP address-level granularity by relying on server logs of a large commercial content delivery network (CDN) that serves close to 3 trillion HTTP requests on a daily basis. Across the whole of 2015, these logs recorded client activity involving 1.2 billion unique IPv4 addresses, the highest ever measured, in agreement with recent estimates. Monthly client IPv4 address counts showed constant growth for years prior, but since 2014, the IPv4 count has stagnated while IPv6 counts have grown. Thus, it seems we have entered an era marked by increased complexity, one in which the sole enumeration of active IPv4 addresses is of little use to characterize recent growth of the Internet as a whole. With this observation in mind, we consider new points of view in the study of global IPv4 address activity. Our analysis shows significant churn in active IPv4 addresses: the set of active IPv4 addresses varies by as much as 25% over the course of a year. Second, by looking across the active addresses in a prefix, we are able to identify and attribute activity patterns to network restructurings, user behaviors, and, in particular, various address assignment practices. Third, by combining spatio-temporal measures of address utilization with measures of traffic volume, and sampling-based estimates of relative host counts, we present novel perspectives on worldwide IPv4 address activity, including empirical observation of under-utilization in some areas, and complete utilization, or exhaustion, in others.Comment: in Proceedings of ACM IMC 201

Understanding how and why quality circles improve standards of practice, enhance professional development and increase psychological well-being of general practitioners: a realist synthesis.

OBJECTIVES To understand how and why participation in quality circles (QCs) improves general practitioners' (GPs) psychological well-being and the quality of their clinical practice. To provide evidence-informed and practical guidance to maintain QCs at local and policy levels. DESIGN A theory-driven mixed method. SETTING Primary healthcare. METHOD We collected data in four stages to develop and refine the programme theory of QCs: (1) coinquiry with Swiss and European expert stakeholders to develop a preliminary programme theory; (2) realist review with systematic searches in MEDLINE, Embase, PsycINFO and CINHAL (1980-2020) to inform the preliminary programme theory; (3) programme refinement through interviews with participants, facilitators, tutors and managers of QCs and (4) consolidation of theory through interviews with QC experts across Europe and examining existing theories. SOURCES OF DATA The coinquiry comprised 4 interviews and 3 focus groups with 50 European experts. From the literature search, we included 108 papers to develop the literature-based programme theory. In stage 3, we used data from 40 participants gathered in 6 interviews and 2 focus groups to refine the programme theory. In stage 4, five interviewees from different healthcare systems consolidated our programme theory. RESULT Requirements for successful QCs are governmental trust in GPs' abilities to deliver quality improvement, training, access to educational material and performance data, protected time and financial resources. Group dynamics strongly influence success; facilitators should ensure participants exchange knowledge and generate new concepts in a safe environment. Peer interaction promotes professional development and psychological well-being. With repetition, participants gain confidence to put their new concepts into practice. CONCLUSION With expert facilitation, clinical review and practice opportunities, QCs can improve the quality of standard practice, enhance professional development and increase psychological well-being in the context of adequate professional and administrative support. PROSPERO REGISTRATION NUMBER CRD42013004826

Rivastigmine in Chinese patients with subcortical vascular dementia

Vincent Mok1, Adrian Wong1, Simon Ho2, Thomas Leung1, Wynnie WM Lam2, Ka Sing Wong11Department of Medicine and Therapeutics; 2Department of Radiology and Organ Imaging, The Chinese University of Hong Kong, Shatin, Hong Kong, ChinaBackground: We explored the efficacy and tolerability of rivastigmine among Chinese patients with subcortical vascular dementia.Methods: Forty subjects were randomized to either placebo (n = 20) or rivastigmine (n = 20) in a double-blind 26-week trial. Outcome measures were cognition (mini-mental state examination, frontal assessment battery), neuropsychiatric inventory (NPI), instrumental activities of daily living, clinical dementia rating scale, and adverse events.Results: No statistical significant benefit could be observed in the active group in any of the efficacy measures. A trend favoring active group was observed only in the NPI subscore of irritability (p = 0.066) and aberrant motor behavior (p = 0.068). Withdrawal rate was 30% and 15% in the active and placebo group, respectively.Conclusion: Among Chinese subcortical vascular dementia patients, there was no apparent cognitive benefit associated with use of rivastigmine over the 6 months period. A trend favoring rivastigmine was observed in certain behavioral measures. Rivastigmine was associated with more withdrawals relative to placebo.Keywords: rivastigmine, subcortical vascular dementia, Chines