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About 10,000 papers for “Directed graph”

Directed Acyclic Graph

National Cancer Institute · Definitions · 2020

A graph whose edges are ordered pairs of vertices or nodes and which contains no path that starts and ends at the same vertex.

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Directed Graph Hashing

Caleb Helbling · arXiv (Cornell University) · 2020

This paper presents several algorithms for hashing directed graphs. The algorithms given are capable of hashing entire graphs as well as assigning hash values to specific nodes in a given graph. The notion of node symmetry is made precise via computation of vertex orbits and the graph automorphism group, and nodes that are symmetrically identical are assigned equal hashes. We also present a novel Merkle-style hashing algorithm that seeks to fulfill the recursive principle that a hash of a node should depend only on the hash of its neighbors. This algorithm works even in the presence of cycles, which would not be possible with a naive approach. Structurally hashing trees has seen widespread use in blockchain, source code version control, and web applications. Despite the popularity of tree hashing, directed graph hashing remains unstudied in the literature. Our algorithms open new possibilities to hashing both directed graphs and more complex data structures that can be reduced to directed graphs such as hypergraphs.

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go-directed-graph

Kuan-Hsi Chen · Harvard Dataverse · 2019

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Directed acyclic graph.

Bruno A. M. P. Besen (5323223), Marcelo Park (277638), Otávio T. Ranzani (10042018) · Figshare · 2021

COPD: Chronic obstructive pulmonary disease; HF: Heart failure; BMI: Body mass index; SOFAnresp: non-respiratory SOFA score; GCS: Glasgow coma scale. * This directed acyclic graph was built with the online version of DAGitty. (TIF)

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Directed acyclic graph.

Anna Marcuzzi (12098179), Paulo Ferreira (3425282), Paul Jarle Mork (2615383) et al. · Figshare · 2025

Variables in black boxes are confounders that are adjusted for in the analyses. To avoid potential residual confounding by offspring age, this variable was also used as a confounder in the analyses. Abbreviations: MSK, musculoskeletal; BMI, body mass index; SES, socioeconomic status. (DOCX)

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Directed acyclic graph.

Shiue-Shan Weng (4578151), Li-Yin Chien (30447), Yi-Ting Huang (383118) et al. · Figshare · 2022

Created with DAGitty (<a href="http://www.dagitty.net/" target="_blank">www.dagitty.net</a>). NICU/PICU, neonatal intensive care unit/pediatric intensive care unit; LBW, low birth weight. The variables with pink color indicate confounders, which require controlling or adjusting. The blue variables with green arrows indicate mediators, which cannot be controlled or adjusted for. The minimal sufficient adjustment sets for estimating the total effect of mode of conception on early breastfeeding outcomes include maternal age, maternal occupational status, abortion history, parity, marital status, socioeconomic status, and pre-existing diseases. (TIF)

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Directed acyclic graph.

Liam Wright (10451355), Neil M. Davies (11349398), David Bann (688911) · Figshare · 2023

The association between (adolescent) cognitive ability and adult BMI may be confounded by family background (including dynastic genetic effects) and other factors shared between siblings. Existing studies typically attempt to control for family background with measured SEP, which, because of the few high-level variables that are used, can be thought of measuring family background with some measurement error. Thus, controlling for measured SEP does not full block confounding through family background. The sibling design instead accounts for family background by design. (TIFF)

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Directed acyclic graph.

Fang Fang (38179), John David Clemens (8787392), Zuo-Feng Zhang (227331) et al. · Figshare · 2024

County characteristics include annual PM2.5 concentration between 2000 and 2018, percentage of adults smokers, percentage of obese adults, percentage of people living under poverty, population density, percentage of owner occupied properties, percentage of adults with less than high school education, percentage of White population, median household income, median house value, percentage of population over 65 years old, percentage of male, percentage of population without an insurance, and percentage of population living in rural area. State policies include stay home orders and facemask mandates.

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Directed acyclic graph.

Jamie Luster (7344476), Abigail Norris Turner (7344479), John P. Henry Jr. (7344482) et al. · Figshare · 2019

The minimally sufficient adjustment set includes the variables frequency of sex, income, race, and year in school.

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Acyclic Directed Graph

Shashi Shekhar, Hui Xiong · Encyclopedia of GIS · 2008

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Directed Acyclic Graph.

Matthieu Doutreligne (16503321), Tristan Struja (3599573), Judith Abecassis (3599456) et al. · Figshare · 2025

<div> Causal inference enables machine learning methods to estimate treatment effects of medical interventions from electronic health records (EHRs). The prevalence of such observational data and the difficulty for randomized controlled trials (RCT) to cover all population/treatment relationships make these methods increasingly attractive for studying causal effects. However, researchers should be wary of many pitfalls. We propose and illustrate a framework for causal inference estimating the effect of albumin on mortality in sepsis using an Intensive Care database (MIMIC-IV) and comparing various sensitivity analyses to results from RCTs as gold-standard. The first step is study design, using the target trial concept and the PICOT framework: Population (patients with sepsis), Intervention (combination of crystalloids and albumin for fluid resuscitation), Control (crystalloids only), Outcome (28-day mortality), Time (intervention start within 24h of admission). We show that too large treatment-initiation times induce immortal time bias. The second step is selection of the confounding variables based on expert knowledge. Increasingly adding confounders enables to recover the RCT results from observational data. As the third step, we assess the influence of multiple models with varying assumptions, showing that a doubly robust estimator (AIPW) with random forests proved to be the most reliable estimator. Results show that these steps are all important for valid causal estimates. A valid causal model can then be used to individualize decision making: subgroup analyses showed that treatment efficacy of albumin was better for patients >60 years old, males, and patients with septic shock. Without causal thinking, machine learning is not enough for optimal clinical decision on an individual patient level. Our step-by-step analytic framework helps avoiding many pitfalls of applying machine learning to EHR data, building models that avoid shortcuts and extract the best decision-making evidence. </div>

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Directed Acyclic Graph.

Tim Reid (398306), Mark Hindell (364276), Jennifer L. Lavers (398307) et al. · Figshare · 2015

Directed Acyclic Graph of model for estimating flesh-footed shearwater population on Lord Howe Island. Rectangles represent derived variables, while ovals represent parameters that are estimated from data with uncertainty. Variables in italics were taken from the literature (see text). Other variables with parameters took vague priors.

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Directed acyclic graph.

Greta E. Abele (13104628), Yury Zablotski (9188197), Melanie Feist (12015570) et al. · Figshare · 2022

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Directed acyclic graph.

Gladymar Pérez Chacón (11805665), Parveen Fathima (4115746), Mark Jones (233817) et al. · Figshare · 2023

Simplified directed acyclic graph describing the proposed causal relationship between pertussis immunization and admissions to hospital with an assigned principal diagnosis of asthma according to the International Classification of Diseases (9th edition, Clinical Modification or 10th edition, Australian Modification), in children born in Western Australia (L21 = 0) or New South Wales (L21 = 1) between 1997 and 1999 (L20). Admissions to hospital with an assigned principal diagnosis of injury, trauma, or poisoning per the same coding schemes represent the negative control outcome of this study (Y6). These outcomes are not in the causal pathway between the exposure of interest (A7) and admissions for asthma (Y18 or its descendant Y19), despite sharing a set of common causes. Figure generated via GeNIe Academic version 4.0.1922.0.[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0291483#pone.0291483.ref001" target="_blank">1</a>]. 1BayesFusion. GeNIe Modeler [Internet]. 2022. Available from: <a href="https://www.bayesfusion.com/genie/" target="_blank">https://www.bayesfusion.com/genie/</a> . (TIF)

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Directed Acyclic Graph.

Elizabeth O. Bodunde (21615797), Fergus P. McCarthy (7586492), Karen O’connor (21615800) et al. · Figshare · 2025

<div> Introduction Limited evidence exists on the association between mode of birth and long-term depression and/or severe anxiety in mothers. We aimed to examine the association between mode of birth and depression and/or severe anxiety by 14 years postpartum. Methods We used data from the Millennium Cohort Study. Data on mode of birth were collected when mothers were 9 months postpartum, and categorized as spontaneous vaginal birth (VB), assisted VB, induced VB, emergency cesarean section (CS), planned CS, and CS after induction. Depression/severe anxiety were collected as one variable and self reported by mothers at 9 months, 3, 5, 7, 11, and 14 years postpartum based on a doctor diagnosis. The primary outcome measure was a diagnosis of depression/severe anxiety up to 14 years postpartum. We used multivariable logistic regression models to estimate crude and adjusted odds ratios (OR) for the association between mode of birth and depression/severe anxiety by 14 years postpartum. Results There were 10,507 singleton mothers included in our analyses. Fully adjusted odds ratio (aOR)for the association between mode of birth and depression/severe anxiety by 14 years postpartum was induced VB, (aOR, 1.13 [95% CI], 1.01–2.28), assisted VB (aOR, 1.03 [95% CI], 0.89–1.19), Emergency CS, (aOR, 1.08 [95% CI], 0.92–1.27), planned CS (aOR, 1.09 [95% CI], 0.93–1.27), and CS after induction (aOR, 1.08 [95% CI], 0.91–1.28). Fully adjusted models did not report any significant association between mode of birth and depression/severe anxiety at other postpartum time points. Conclusions The present findings provide support for association between induction of labor and the risk of long-term depression/severe anxiety by 14 years postpartum. The findings provide no evidence to support association between other modes of birth and maternal depression/anxiety. </div>

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Directed Acyclic Graph.

Yo Ishihara (4510288), Kiyomitsu Fukaguchi (19065995), Hiroshi Koyama (183459) · Figshare · 2025

<div> Objectives Hospitalization can lead to a loss of physical function among older adults. While pet ownership has been reported to have beneficial effects on physical function, its impact on hospitalized patients remains unclear. We examined the association between pet ownership upon admission and physical function during hospitalization. Methods This single-center, retrospective, observational study was conducted between April 2013 and April 2023. Patients aged ≥65 years who were hospitalized for the first time due to pneumonia at our facility were included. Cases were identified through medical record searches using the keywords “pet”, “dog”, “cat”, “ownership”, and “keeping”. Patients with unclear pet ownership status in the medical records were excluded from the analysis. Patients were classified into two groups: Pet Owners (PO) and Non-Pet Owners (NPO) upon admission. The Barthel index (BI) gain (the difference between admission and discharge BI scores) and BI efficiency (BI gain divided by hospital stay) were compared. Logistic regression was performed for patients with a BI gain >0 and discharge BI scores >85, indicating independence without functional decline, after adjusting for covariates. Results A total of 248 patients were initially screened, we finally included 172 patients (69.4%) in the PO group and 46 patients (18.5%) in the NPO group. The median BI gain was 10 (0–30) and 2.5 (0.0–26.3) in the PO and NPO groups (p = 0.24), respectively. The median BI efficiency was 0.48 (0.00–1.87) and 0.16 (0.00–1.27) in the PO and NPO groups (p = 0.062), respectively. Current pet ownership was not associated with independence without functional decline, with an adjusted odds ratio of 0.68 (95% confidence interval, 0.15–3.94; p = 0.63). Conclusions This study found no association between current pet ownership and the maintenance of physical function in hospitalized older adults. </div>

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Directed acyclic graph.

Camille Davisse-Paturet (13385340), Massimiliano Orri (560000), Stéphane Legleye (512832) et al. · Figshare · 2023

BackgroundA higher risk of suicidal ideation associated with self-report of Coronavirus Disease 2019 (COVID-19)-like symptoms or COVID-19 infection has been observed in cross-sectional studies, but evidence from longitudinal studies remains limited. The aims of this study were 2-fold: (1) to explore if self-reported COVID-19-like symptoms in 2020 were associated with suicidal ideation in 2021; (2) to explore if the association also existed when using a biological marker of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in 2020.Methods and findingsA total of 52,050 participants from the French EpiCov cohort were included (median follow-up time = 13.7 months). In terms of demographics, 53.84% were women, 60.92% were over 45 years old, 82.01% were born in mainland France from parents born in mainland France, and 59.38% completed high school. COVID-19-like symptoms were defined as participant report of a sudden loss of taste/smell or fever alongside cough, shortness of breath, or chest oppression, between February and November 2020. Symptoms were self-reported at baseline in May 2020 and at the first follow-up in Autumn 2020. Serology-confirmed SARS-CoV-2 infection in 2020 was derived from Spike protein ELISA test screening in dried-blood-spot samples. Samples were collected from October 2020 to March 2021, with 94.4% collected in 2020. Suicidal ideation since December 2020 was self-reported at the second follow-up in Summer 2021. Associations of self-reported COVID-19-like symptoms and serology-confirmed SARS-CoV-2 infection in 2020 with suicidal ideation in 2021 were ascertained using modified Poisson regression models, weighted by inverse probability weights computed from propensity scores. Among the 52,050 participants, 1.68% [1.54% to 1.82%] reported suicidal ideation in 2021, 9.57% [9.24% to 9.90%] had a serology-confirmed SARS-CoV-2 infection in 2020, and 13.23% [12.86% to 13.61%] reported COVID-19-like symptoms in 2020. Self-reported COVID-19-like symptoms in 2020 were associated with higher risks of later suicidal ideation in 2021 (Relative Riskipw [95% CI] = 1.43 [1.20 to 1.69]), while serology-confirmed SARS-CoV-2 infection in 2020 was not (RRipw = 0.89 [0.70 to 1.13]). Limitations of this study include the use of a single question to assess suicidal ideation, the use of self-reported history of mental health disorders, and limited generalizability due to attrition bias.ConclusionsSelf-reported COVID-19-like symptoms in 2020, but not serology-confirmed SARS-CoV-2 infection in 2020, were associated with a higher risk of subsequent suicidal ideation in 2021. The exact role of SARS-CoV-2 infection with respect to suicide risk has yet to be clarified. Including mental health resources in COVID-19-related settings could encourage symptomatic individuals to care for their mental health and limit suicidal ideation to emerge or worsen.

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Directed acyclic graph.

Bente Øvrebø (8563419), Tonje H. Stea (11226208), Ingunn H. Bergh (11226205) et al. · Figshare · 2022

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Fuzzy directed graph.

Waheed Ahmad Khan (21182380), Hajra Begum (22411304), Trung Tuan Nguyen (22411307) et al. · Figshare · 2025

<div> Recent developments in the theory of fuzzy graphs have led to many extensions for modeling real-world problems involving uncertainty. Among these, competition graphs are crucial for representing competitive and ecological systems. In this study, the notion of bipolar picture fuzzy competition graphs, along with several generalizations including bipolar picture fuzzy k-competition graphs, p-competition graphs, and m-competition graphs are introduced. Several characteristics of these newly established graphs are investigated. We also explore their structural properties and apply the models to real-world competitive scenarios using computational frameworks. A comparative study is conducted to demonstrate the improved efficiency of the proposed models over existing approaches. </div>

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Directed acyclic graph.

Binh Nguyen (7327), Philip Clare (4402513), Gregore I. Mielke (5658868) et al. · Figshare · 2024

<div>BackgroundThere is little long-term causal evidence on the effect of physical activity on health-related quality of life. This study aimed to examine the associations between longitudinal patterns of physical activity over 15 years and health-related quality of life in both the physical and mental health domains, in a cohort of middle-aged Australian women.Methods and findingsWe used data collected at 3-year intervals (1998 to 2019) from 11,336 participants in the Australian Longitudinal Study on Women’s Health (ALSWH) (1946 to 1951 birth cohort). Primary outcomes were the physical (PCS) and mental health component summary (MCS) scores (range from 0 to 100; higher scores indicate higher perceived physical/mental health) from the SF-36 in 2019 (when women aged 68 to 73 years). Using target trial emulation to imitate a randomized controlled trial (RCT), we tested 2 interventions: (1) meeting the World Health Organization (WHO) physical activity guidelines consistently throughout the 15-year “exposure period” (2001 to 2016; when women aged 50–55 to 65–70 years; physical activity assessed every 3 years); and (2) not meeting the guidelines at the beginning of the exposure period but starting to first meet the guidelines at age 55, 60, or 65; against the control of not meeting the guidelines throughout the exposure period. Analysis controlled for confounding using marginal structural models which were adjusted for sociodemographic and health variables and conditions. Consistent adherence to guidelines during the exposure period (PCS: 46.93 [99.5% confidence interval [CI]: 46.32, 47.54]) and first starting to meet the guidelines at age 55 (PCS: 46.96 [99.5% CI: 45.53, 48.40]) were associated with three-point higher PCS (mean score difference: 3.0 [99.5% CI: 1.8, 4.1] and 3.0 [99.5% CI:1.2, 4.8]) than consistent non-adherence (PCS: 43.90 [99.5% CI: 42.79, 45.01]). We found a similar pattern for most SF-36 subscales but no significant effects of the interventions on MCS. The main limitations of the study were that it may not account for all underlying health conditions and/or other unmeasured or insufficiently measured confounders, the use of self-reported physical activity and that findings may not be generalizable to all mid-age women.ConclusionsResults from the emulated RCT suggest women should be active throughout mid-age, ideally increasing activity levels to meet the guidelines by age 55, to gain the most benefits for physical health in later life.</div>

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