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Association and agreement of contact-based smartphone photoplethysmography (PPG) compared with electrocardiography (ECG) : A protocol for a systematic review and meta-analysis
Get PDFMobile health (mHealth), leveraging mobile devices for health measurement and promotion, is rapidly growing. Smartphone cameras can perform photoplethysmography (PPG) to estimate pulse rate (PR) and other features of the cardiac cycle. However, establishing the validity of PR-PPG is essential before it can be adopted for health care applications. There is a pervasive belief that PR-PPG is analogous to heart rate (HR) derived from electrocardiograms (ECGs), and we will conduct a systematic review and meta-analysis to support or challenge this supposition. This study aims to synthesize quantitative evidence on the validity of PPG derived from mobile devices (ie, smartphones) for the assessment of HR compared with the gold standard ECG assessment. A comprehensive literature search will be performed on CINAHL Ultimate, MEDLINE, ScienceDirect, and Scopus using a predefined search strategy. All retrieved citations will be imported into Rayyan for screening and data management. A minimum of 2 independent reviewers will conduct the title and abstract screening, followed by 2 independent reviewers who will perform full-text screening and data extraction. All stages will be guided by predefined inclusion and exclusion criteria, which will be pilot-tested to ensure consistency and reliability. Any discrepancies will be resolved through discussion with a third reviewer or during a research team meeting. Intrarater reliability will be quantified at the title and abstract stage and the full-text review stage using Cohen κ. To ensure clarity and consistency in the presentation of study characteristics and findings, both narrative synthesis and tabular formats will be used. This review will include studies that report the association and agreement between resting HR and PR from PPG using contact-based smartphone devices versus ECG as the gold standard. PPG signals will be obtained using a contact-based approach, defined as finger-on-camera measurements with the smartphone's built-in camera and flash. Studies will be excluded if they (1) do not use PPG using contact-based smartphone devices, (2) compare PPG to another collection method other than ECG, or (3) are review articles or case studies. To inform clinical procedures and future studies, the results will contain data on PR-PPG and HR-ECG association (correlations) and agreement (Bland-Altman analysis), sampling devices, and operating systems. This project is unfunded, and the initial screening is expected to start in the first quarter of 2026, with results anticipated to be published in the first quarter of 2027. The projected timeline for the study includes title and abstract screening from the first quarter of 2026, followed by full-text screening in the second quarter of 2026. Results are anticipated by the third quarter of 2026, with publication expected in the first quarter of 2027. Throughout this period, database searches will be regularly updated to capture any newly published studies meeting the inclusion criteria. This review will provide a comprehensive understanding of the association and agreement between PR-PPG and HR-ECG. The findings may inform future adoption of PR-PPG and HR-ECG with insights into device or setting characteristics for best agreement or associatio
Cognitive function is associated with the progression of non-tremor motor symptoms in Parkinson’s disease
Get PDFBackground: Parkinson’s disease (PD) is characterized by motor impairment which consists of tremor and non-tremor symptoms. Cognitive function may overlap with specific aspects of voluntary movement and action initiation. This study aims to investigate associations between global cognition and the severity and longitudinal progression of tremor and non-tremor motor symptoms in PD. Methods: As part of the Oxford Quantification in Parkinsonism (OxQUIP) study, 84 participants with PD were tested over seven visits at three-month intervals. At each visit, participants completed standardized global cognitive (MoCA) and motor (MDS-UPDRS-III) assessments. Tremor and non-tremor motor subscores were derived from corresponding MDS-UPDRS-III items. Linear mixed-effects models were calculated to analyze the effect of global cognition at baseline on the progression of (i) overall motor impairment, (ii) non-tremor motor symptoms, and (iii) tremor symptoms. Results: We did not find an association between MoCA scores and MDS-UPDRS-III severity, but there was a significant interaction between global cognition and the progression of motor impairment (p=0.005). Lower MoCA scores were linked with steeper progression of non-tremor motor symptoms (p<0.001), but not tremor symptoms (p=0.380). Conclusions: Global cognition at baseline is associated with the progression, but not severity, of motor impairment in PD; this finding is specific to non-tremor and not tremor motor symptoms. While both motor subdomains are known to be linked with dysfunction of sub-cortical circuits, non-tremor symptoms may also be influenced by disrupted cognitive inputs. Our results highlight the potential value of incorporating cognitive tools to complement motor examination in PD assessment
Exploring Emotion Timeline Patterns in Social Media for Automatic Identification of Depression and Anxiety
No full textOver the past years, public awareness of mental health issues has increased, and people are paying more attention to their mental well-being. Depressive and anxiety disorders are among the key causes of the global disease burden. These two mental conditions can disrupt the daily lives of people affected by them and, in severe cases, depression may even lead to suicide. To prevent suicide and alleviate the burden on the affected individuals, researchers have increasingly focused on automatically detecting these mental conditions using social media data, as people with mental health issues often seek supports and share their feelings on social media. Since depression and anxiety are chronic issues and related to emotions, past studies have utilised emotion information to identify social media users with depression and anxiety. However, these emotion features used in the past studies are often static, lacking the temporal fluctuation patterns that can effectively reflect the characteristics of these mental conditions. To address this issue, I propose a novel method that applies the timeline Shapelet classification method, a time series analysis method, to the automatic detection of depression and anxiety based on emotion intensity timeline patterns. This study involves two languages. I first created a new Thai dataset for depression and anxiety detection. Next, I selected and modified an existing English dataset for depression detection. Both datasets contain users' tweeting histories in X. Tweets in the Thai dataset were labelled with 26 emotion intensities by both human annotators and a Large Language Model (LLM). In contrast, tweets in the English dataset were automatically labelled with intensities of four emotions using an LLM. Based on the manually annotated Thai dataset, depression and anxiety are found to be associated with 14 and 10 emotions respectively. My study demonstrates that Shapelet classifiers can identify emotion intensity timeline patterns associated with depression and anxiety. Using these patterns, the classifiers detected depression with a precision of 0.7292 on the English dataset, and achieved maximum precision of 1.00 in detecting both depression and anxiety on the Thai dataset. These classifiers also outperformed benchmark models on the Thai dataset in detecting the two conditions, although they produced relatively low recall on both datasets. Finally, this study also investigates the potential of porting emotion intensity timeline patterns for cross-lingual depression detection, from English to Thai in this case. In my experiment, the Shapelet classifiers trained on English dataset could effectively detect depression in the Thai dataset, showing the potential of this approach for cross-lingual application, particularly for under-resourced languages
On the inversion of polynomials of discrete Laplace matrices
No full textThe efficient inversion of matrix polynomials is a critical challenge in computational mathematics. We design a procedure to determine the inverse of matrices polynomial of multidimensional Laplace matrices. The method is based on eigenvector and eigenvalue expansions. The method is consistent with previously known expressions of the inverse discretized Laplacian in one spatial dimension (Vermolen et al., 2022). The formalism is further extended to obtain closed form expressions for time-dependent problems
A Robust HECC-based Authentication and Key Agreement for UAV-enabled SAR Networks
Get PDFUnmanned aerial vehicles (UAVs) have become an indispensable tool in search-and-rescue (SAR) missions, playing a crucial role in locating victims and delivering essential supplies in disaster-stricken areas. However, due to communications in open channels, these unignorable security issues including unauthorized data access, data tampering and leakage, potentially disturb, or even damage the SAR missions. The authentication and key agreement (AKA) technologies are designed to try to allow only verified legal entities can access the data securely with a negotiated session key. Despite the advantages of AKA, existing UAV-specific AKA solutions are unable to resist specific attacks which threaten the security of authentication and session key, and are plagued from the unsatisfactory performance given limited resources of UAVs. To address these issues, based on hyperelliptic curve cryptography (HECC), we propose a robust AKA for UAV enabled SAR network and preserve the desiring performance as well. With detailed security analysis, we demonstrate the robustness of our scheme under the eCK Adversary Model. Furthermore, the performance analysis shows the efficiency and utility of our design in terms of computational overhead and communication cost, in which it indicates that our scheme can be applied to the UAV-enabled SAR network
Exact Multiple Change-Point Detection Via Smallest Valid Partitioning
No full textWe introduce smallest valid partitioning (SVP), a segmentation method for multiple change-point detection in time-series. SVP relies on a local notion of segment validity: a candidate segment is retained only if it passes a user-chosen validity test (e.g., a single change-point test). From the collection of valid segments, we propose a coherent aggregation procedure that constructs a global segmentation which is the exact solution of an optimization problem. Our main contribution is the use of a lexicographic order for the optimization problem that prioritizes parsimony. We analyze the computational complexity of the resulting procedure, which ranges from linear to cubic time depending on the chosen cost and validity functions, the data regime and the number of detected changes. Finally, we assess the quality of SVP through comparisons with standard optimal partitioning algorithms, showing that SVP yields competitive segmentations while explicitly enforcing segment validity. The flexibility of SVP makes it applicable to a broad class of problems; as an illustration, we demonstrate robust change-point detection by encoding robustness in the validity criterion
Reproducing Khwāja sarā : From Premodern, Colonial to Postcolonial Cultural and Legal Discourses
No full textThe contemporary contestations of the khwāja sarā identity present a significant cultural and social problem within Pakistani society. This thesis interrogates how the legal and cultural status of khwāja sarā is being reconfigured in Pakistan today. A critical review of the contemporary understandings surrounding khwāja sarā revealed that these understandings are embedded within historical, cultural and colonial legal contexts. In this thesis, I do not define the term khwāja sarā as it has undergone layered historical, cultural, and legal shifts across premodern, colonial, postcolonial, and contemporary contexts, and defining it would undermine the spirit of this thesis. This thesis seeks to excavate meanings that have been obscured, reconfigured, and buried under colonial weight through encounters with South Asian land, histories, and epistemologies. Therefore, this thesis took a tripartite approach by pursuing three levels of enquiry to chart the conceptual genealogy of the khwāja sarā; (i) a historical-cultural exploration of premodern Islamic and colonial legal discourses in the context of the Indian subcontinent; (ii) an examination of contemporary legal, judicial and activist discourses; and (iii) the contemporary fictional media (cultural) discourses in Pakistan. These three lines of enquiry are developed to understand how colonial and classical Islamic epistemes converge and overlap in ways that conflate historical cultural and legal trajectories of khwāja sarā identity. This convergence and overlap create epistemic conflicts and tensions, which continue to entangle the khwāja sarā identity in the ongoing confusion of gender categories in Pakistan today. Ethnographic Content Analysis (ECA) was used in an original and innovative way to examine a range of materials: colonial legal texts, contemporary legal, judicial texts, the transgender activist discourses within Pakistan and beyond, and ethnographic research on khwāja sarā. These materials are seen as interconnected and deeply contextualised, revealing the ways in which colonial configurations have persisted and continued to shape the contemporary khwāja sarā discourses. This study also introduces a cross-genre approach by bringing together law and fiction into conversation – genres that have never been examined together – demonstrating the ways in which law and culture shape each other. Based on my analysis along these three lines of inquiry, I argue in this thesis that the convergence and overlapping of colonial and classical Islamic epistemes produces gendered epistemic conflation with regard to sex, sexuality and desire of khwāja sarā in both colonial and postcolonial discourses. This concept can be defined as disparate ways of knowing which merge different cultural and historical frameworks without resolving the tensions or recognising the genealogies.” In the first line of enquiry, I argue that this epistemic conflation results from the displacement of classical Islamic legal categories (khunthā and liwāṭ) through the colonial legal discourse. In the second line of enquiry, I argue that the contemporary legal, judicial, activist and modernist/Islamic discourses reproduce this epistemic conflation in ways where the gender/sex distinctions collapse, and criminal and pathologizing narratives are mapped onto the Islamic and historical cultural categories (khunthā and khwāja sarā). Consequently, this epistemic conflation obscures the historical distinctness and cultural complexity of the khwāja sarā. In the third line of enquiry, I argue that the selected media representations perpetuate these epistemic conflations by reinscribing stereotypes that were the outcome of the colonial machination, and by supporting the contemporary transgender legal gender categories, often translating them into characters and narratives that align with global transgender taxonomies. This study contributes to the study of Islam, gender and sexuality – particularly Khaled El-Rouayheb, Joseph Massad and Vanja Hamzic – that contends premodern Islamic/Muslim trajectories of understandings of sex, gender and sexuality are rooted in fluidity and complexity but also demonstrate that Western/European frameworks and epistemologies disrupt the Islamic/Muslim traditions/epistemologies. To this body of knowledge, I contribute the illustration and conceptualisation of the gendered epistemic conflation which emerges from the overlapping, and at times contradictory, frameworks of modern and pre-modern, Western and Islamic conceptions of gender and sexuality. Overall, this thesis recognises the need to reclaim epistemic distinctions. It argues that the complex and open model of sex, sexuality and desire of Islamic law and premodern Muslim traditions has the potential to contribute to rethinking of a cultural and legal gender model that accommodates legitimacy of homoerotic desires for all sexes, not just for the khunthā. This model provides an opportunity to avoid the polarising narratives that dominate the contemporary legal, cultural, Islamic and activist discourses, and instead proposes an approach that is historically, culturally and Islamically sensitive, and is conducive to addressing the needs of the khwāja sarā community
Pareto optimal regulatory strategies for coupled ridesourcing and taxi markets with impatient passengers
Get PDFThis study develops a multi-objective bi-level programming model to identify the Pareto optimal combined regulatory strategy that simultaneously accounts for passengers, taxi drivers, ridesourcing vehicle (RSV) drivers, and the transportation network company (TNC). The upper level determines four regulatory controls, including the RSV fleet cap, taxi fare rate, government-guided RSV fare rate, and TNC wage rate floor, while the lower level obtains the steady-state market performance, which is formulated as a fixed-point problem and approximated through iterative agent-based simulations. To solve the model, a multi-objective Bayesian optimization algorithm is developed. Based on the DiDi dataset collected from Hangzhou City in 2018, our experiments demonstrate that no regulatory strategy can simultaneously benefit all stakeholders. If the government considers maximizing vehicle utilization as a secondary criterion, then it should decrease the RSV fleet cap, impose higher fare rates, and allow the TNC to pay lower wages, compared with the benchmark scenario. Furthermore, it is recommended that the government should avoid regulations that primarily favor passengers or the TNC, as our results reveal that such policies could harm other stakeholders and reduce vehicle utilization by up to 11.6%. Finally, if passengers’ impatience is overlooked, taxi drivers may lose 23.3% of potential profits
