Complete Space Research Articles

The Cauchy completion of a symmetric b-uniform filter space

The Cauchy completion of a symmetric b-uniform filter space

Peertrap: An Unstructured P2P Botnet Detection Framework Based on SAW Community Discovery

Botnet has become one of the serious threats to the Internet ecosystem, and botnet detection is crucial for tracking and mitigating network threats on the Internet. In the evolution of emerging botnets, peer-to-peer (P2P) botnets are more dangerous and resistant because of their distributed characteristics. Among them, unstructured P2P botnets use custom protocols for communication, which can be integrated with legitimate P2P traffic. Moreover, their topological structure is more complex, and a complete topology cannot be obtained easily, making them more concealed and difficult to detect. The bot itself is a kind of overlay network, and research shows that the nodes with shared neighbors usually belong to a certain community. Aiming at unstructured P2P botnets and exploiting complex network theory, from the perspective of shared neighbor nodes, this article proposes a botnet detection framework called Peertrap based on self-avoiding random walks (SAW) community detection under the condition of incomplete topological information. Firstly, network traffic is converted into Netflow, by utilizing Apache Flink big data platform. Also, a P2P traffic cluster feature extraction rule is proposed for distinguishing P2P traffic from non-P2P traffic, and it is formulated by using the upstream and downstream traffic and address distribution threshold features. Then, the confidence between P2P clusters is calculated by the Jaccard coefficient to construct a shared neighbor graph, and the same type of P2P communities are mined by hierarchical clustering using SAW algorithm combined with PCA. Finally, two community attributes, mean address distribution degree and mean closeness degree, are used to distinguish botnets. Experiments are conducted on three unstructured P2P botnets datasets, Sality, Kelihos, and ZeroAccess, and the CTU classic datasets, and then good detection results can be achieved. The framework overcomes one of the most critical P2P botnet detection challenges. It can detect P2P bots with high accuracy in the presence of legitimate P2P traffic, incomplete information network topology, and C&C channel encryption. Our method embodies the typical application of complex network theory in botnet detection field, and it can detect botnets from different families in the network, with good parallelism and scalability.

Comparative Assessment of Pixel and Object-Based Approaches for Mapping of Olive Tree Crowns Based on UAV Multispectral Imagery

Pixel-based (PB) and geographic-object-based (GEOBIA) classification approaches allow the extraction of different objects from multispectral images (MS). The primary goal of this research was the analysis of UAV imagery applicability and accuracy assessment of MLC and SVM classification algorithms within PB and GEOBIA classification approaches. The secondary goal was to use different accuracy assessment metrics to determine which of the two tested classification algorithms (SVM and MLC) most reliably distinguishes olive tree crowns and which approach is more accurate (PB or GEOBIA). The third goal was to add false polygon samples for Correctness (COR), Completeness (COM) and Overall Quality (OQ) metrics and use them to calculate the Total Accuracy (TA). The methodology can be divided into six steps, from data acquisition to selection of the best classification algorithm after accuracy assessment. High-quality DOP (digital orthophoto) and UAVMS were generated. A new accuracy metric, called Total Accuracy (TA), combined both false and true positive polygon samples, thus providing a more comprehensive insight into the assessed classification accuracy. The SVM (GEOBIA) was the most reliable classification algorithm for extracting olive tree crowns from UAVMS imagery. The assessment carried out indicated that application of GEOBIA-SVM achieved a TACOR of 0.527, TACOM of 0.811, TAOQ of 0.745, Overall Accuracy (OA) of 0.926 or 0.980 and Area Under Curve (AUC) value of 0.904 or 0.929. The calculated accuracy metrics confirmed that the GEOBIA approach (SVM and MLC) achieved more accurate olive tree crown extraction than the PB approach (SVM and MLC) if applied to classifying VHR UAVMS imagery. The SVM classification algorithm extracted olive tree crowns more accurately than MLC in both approaches. However, the accuracy assessment has proven that PB classification algorithms can also achieve satisfactory accuracy.

Mapping of Dwellings in IDP/Refugee Settlements from Very High-Resolution Satellite Imagery Using a Mask Region-Based Convolutional Neural Network

Earth-observation-based mapping plays a critical role in humanitarian responses by providing timely and accurate information in inaccessible areas, or in situations where frequent updates and monitoring are required, such as in internally displaced population (IDP)/refugee settlements. Manual information extraction pipelines are slow and resource inefficient. Advances in deep learning, especially convolutional neural networks (CNNs), are providing state-of-the-art possibilities for automation in information extraction. This study investigates a deep convolutional neural network-based Mask R-CNN model for dwelling extractions in IDP/refugee settlements. The study uses a time series of very high-resolution satellite images from WorldView-2 and WorldView-3. The model was trained with transfer learning through domain adaptation from nonremote sensing tasks. The capability of a model trained on historical images to detect dwelling features on completely unseen newly obtained images through temporal transfer was investigated. The results show that transfer learning provides better performance than training the model from scratch, with an MIoU range of 4.5 to 15.3%, and a range of 18.6 to 25.6% for the overall quality of the extracted dwellings, which varied on the bases of the source of the pretrained weight and the input image. Once it was trained on historical images, the model achieved 62.9, 89.3, and 77% for the object-based mean intersection over union (MIoU), completeness, and quality metrics, respectively, on completely unseen images.

Kepler Bonus: Aperture Photometry Light Curves of EXBA Sources

Abstract NASA’s Kepler mission observed background regions across its field of view for more than 3 consecutive yr using custom designed superapertures (EXBA masks). Since these apertures were designed to capture a region of the sky rather than single targets, the Kepler Science Data Processing Pipeline produced target pixel files but did not produce light curves for the sources within these background regions. In this work, we produce light curves for 9327 sources observed in the EXBA masks. These light curves are generated using aperture photometry estimated from the instrument’s pixel response function (PRF) profile computed from Kepler's full-frame images. The PRF models enable the creation of apertures that follow the characteristic shapes of the point-spread function in the image and the computation of flux completeness and contamination metrics. The light curves are available at MAST as a high-level science product (kbonus-apexba). Alongside this data set, we present kepler-apertures, a Python library to compute PRF models and use them to perform aperture photometry on Kepler-like data. Using light curves from the EXBA masks, we found an exoplanet candidate around Gaia EDR3 2077240046296834304 consistent with a large planet companion with a 0.81 R J radius. Additionally, we report a catalog of 69 eclipsing binaries. We encourage the community to exploit this new data set to perform in-depth time domain analysis, such as eclipsing binaries demographics and other types of studies.

The balanced metrics and cscK metrics on certain holomorphic ball bundles

In this paper, we use the well-known Calabi ansatz, further generalized by Hwang-Singer, to study the existence of balanced metrics and constant scalar curvature Kähler (cscK for short) metrics on certain holomorphic ball bundles M which are locally expressed as M={(z,u,w)∈Ω×Cd1×Cd2:eλ1ϕ(z)‖u‖2+eλ2ϕ(z)‖w‖2<1}. Let g be the Kähler metric on M associated with the Kähler forms locally expressed as ω=−1∂∂‾(ϕ(z)+F(eλ1ϕ(z)‖u‖2+eλ2ϕ(z)‖w‖2)). Firstly, we obtain sufficient and necessary conditions for g to be cscK metrics. Secondly, using this result, we obtain necessary and sufficient conditions for mg to be balanced metrics for all sufficiently large positive integer numbers m. Finally, we obtain complete cscK metrics and balanced metrics on the ball bundles over simply connected Riemann surfaces. The main contribution of this paper is the explicit construction of complete, non-compact cscK metrics and balanced metrics.

Geometrically exact static isogeometric analysis of an arbitrarily curved spatial Bernoulli–Euler beam

The objective of this research is the development of a geometrically exact model for the analysis of arbitrarily curved spatial Bernoulli–Euler beams. The complete metric of the beam is utilized in order to include the effect of curviness on the nonlinear distribution of axial strain over the cross section. The exact constitutive relation between energetically conjugated pairs is employed, along with four reduced relations. The isogeometric approach, which allows smooth connections between finite elements, is used for the spatial discretization of the weak form. Two methods for updating the local vector basis are applied and discussed in the context of finite rotations. All the requirements of geometrically exact beam theory are satisfied, such as objectivity and path-independence. The accuracy of the formulation is verified by a thorough numerical analysis. The influence of the curviness on the structural response is scrutinized for two classic examples. If the exact response of the structure is sought, the curviness must be considered when choosing the appropriate beam model.

Near fixed point, near fixed interval circle and their equivalence classes in a $b-$interval metric space

We introduce a novel distance structure called a b−interval metric space to generalize and extend metric interval space. Also, we demonstrate that the collection of open balls, which forms a basis of a b−interval metric space, generates a T0−topology on it. Further, we define topological notions like an open ball, closed ball, b−convergence, b−Cauchy sequence and completeness of the space on a b−interval metric space to create an environment for the survival of a near fixed point and a unique equivalence class of near fixed point. Towards the end, we introduce notions of interval circle, fixed interval circle, its equivalence class and established the existence of a near fixed interval circle and its equivalence interval C−class of near fixed interval circle to study the geometric properties of non-unique equivalence C−classes of nearly fixed interval circles.

Sentiment analysis of users reviews in Facebook: comparison of TEXTBLOB and DOSTOEVSKY libraries

This article examines the work of two Python libraries TextBlob and Dostoevsky for determining the sentiment of reviews in Russian. The TextBlob library does not directly provide sentiment analysis of texts in Russian, but it has the ability to transfer such texts to the input of the Google Translate translator, in order to then evaluate the polarity of these texts based on the generated English translations. The second Dostoevsky library was created specifically for sentiment analysis of texts in Russian and is trained on the largest Russian-language sentiment corpus RuSentiment, which contains more than 30 thousand manually annotated messages. To compare these libraries, this article uses real feedback from residents of the city of Nur-Sultan about the quality of life in the capital, including about the activities of city services and the housing and communal sector, the work of service facilities, education, health care, culture, etc., posted on public Facebook groups. The results of the sentiment analysis carried out are evaluated using generally accepted metrics of accuracy, completeness and F-measure and demonstrate a slight superiority of the Dostoevsky library.

Abstract 11730: Data Quality and Monitoring Completion Rates Are Similar Between Clinic-Applied and Self-Applied Continuous ECG Monitoring Patches Prior to and During COVID-19

Introduction: Prior to COVID-19, ECG patches (ECGp) were applied almost exclusively in-clinic (CA) by technicians which required an office visit and fee. Since the pandemic, direct-to-patient, self-applied patch use (SA) has substantially increased, though the metrics surrounding SA are unknown. This study compares monitoring completion rates and data quality between CA and SA ECGp prior to and during COVID-19. Hypothesis: CA and SA ECGp have similar data quality and monitoring completion metrics. Methods: We performed a retrospective cohort analysis of patients prescribed an iRhythm Zio XT patch at Northwestern Memorial Hospital during the “pre-COVID” (3/1/2019-3/1/2020) and “COVID” (4/1/2020-4/1/2021) timeframes. Differences in ECGp with data available, actual vs prescribed wear time, and analyzable data between groups were assessed. ECGp without data was defined as devices which were not returned or not activated. Results: The cohort included 29,118 ECGp prescriptions; 13,180 pre-COVID (45%). The cohort was 56% female with mean age of 59.3 + 17.7 years. Palpitations (29%) and atrial fibrillation (19%) were the most common indications. In the pre-COVID cohort, there were no (0%) SA ECGp and data were available for 12,932 CA patches. In the COVID cohort, 34% of ECGp were SA; data were available for 10,231 CA ECGp and 4,902 SA ECGp. Average delay between prescription and SA ECGp activation was 8.1 ± 12.2 days. Comparisons between percent analyzable data, wear times, and ECGp with data available are shown in figure 1. Conclusions: COVID-19 resulted in a rapid adoption of SA ECGp use. Compared to CA, SA was associated with an inherent delay in ECGp application and a higher proportion of ECGp without data. However, there was no difference in actual vs prescribed wear time and a small but statistically significant decrease in percent analyzable data. These differences must be balanced with the additional cost and need for in-person visit for CA vs SA.

Effects of frequency mismatch on amplitude death in delay-coupled oscillators

The present paper analytically reveals the effects of frequency mismatch on the stability of an equilibrium point within a pair of Stuart-Landau oscillators coupled by a delay connection. By analyzing the roots of the characteristic function governing the stability, we find that there exist four types of boundary curves of stability in a coupling parameters space. These four types depend only on the frequency mismatch. The analytical results allow us to design coupling parameters and frequency mismatch such that the equilibrium point is locally stable. We show that, if we choose appropriate frequency mismatches and delay times, then it is possible to induce amplitude death with strong stability, even by weak coupling. In addition, we show that parts of these analytical results are valid for oscillator networks with complete bipartite topologies.

Investigating Requirements Completeness Metrics for Requirements Schemas Using Requirements Engineering Approach of Data Warehouse: A Formal and Empirical Validation

Investigating Requirements Completeness Metrics for Requirements Schemas Using Requirements Engineering Approach of Data Warehouse: A Formal and Empirical Validation

Complete noncompact G2-manifolds from asymptotically conical Calabi–Yau 3-folds

We develop a powerful new analytic method to construct complete noncompact Ricci-flat 7-manifolds, more specifically G2-manifolds, that is, Riemannian 7-manifolds (M,g) whose holonomy group is the compact exceptional Lie group G2. Our construction gives the first general analytic construction of complete noncompact Ricci-flat metrics in any odd dimension and establishes a link with the Cheeger–Fukaya–Gromov theory of collapse with bounded curvature. The construction starts with a complete noncompact asymptotically conical Calabi–Yau 3-fold B and a circle bundle M→B satisfying a necessary topological condition. Our method then produces a 1-parameter family of circle-invariant complete G2-metrics gϵ on M that collapses with bounded curvature as ϵ→0 to the original Calabi–Yau metric on the base B. The G2-metrics we construct have controlled asymptotic geometry at infinity, so-called asymptotically locally conical (ALC) metrics; these are the natural higher-dimensional analogues of the asymptotically locally flat (ALF) metrics that are well known in 4-dimensional hyper-Kähler geometry. We give two illustrations of the strength of our method. First, we use it to construct infinitely many diffeomorphism types of complete noncompact simply connected G2-manifolds; previously only a handful of such diffeomorphism types was known. Second, we use it to prove the existence of continuous families of complete noncompact G2-metrics of arbitrarily high dimension; previously only rigid or 1-parameter families of complete noncompact G2-metrics were known.

Validation of a pandemic-proof, decentralized cardiovascular trial: scalable design produces rapid recruitment, high engagement and protocol adherence in DeTAP (Decentralized Trial in Afib Patients)

Abstract Background The COVID-19 pandemic has curtailed clinical trial activity significantly. Decentralized clinical trial (DCT) designs may lower cost, expand trial access, and reduce exposure risk for patients and staff. Whether such designs can be used for large, pivotal drug trials is not known. Purpose We performed a feasibility study to inform whether a large phase 3 Cardiovascular DCT can achieve high quality trial results and also withstand health crises such as the COVID-19 pandemic. The DeTAP (Decentralized Trial in Afib Patients) was a single-arm, observational study that integrated a suite of digital health technologies, including paired home sensor devices, into a 100% virtual trial experience for atrial fibrillation (AF) patients on anticoagulation. Methods We recruited 100 AF patients over age 55 on oral anticoagulation (OAC) by traditional methods or by social media ads placed California-wide. Subjects completed an online prescreening, uploaded their active OAC prescription, and completed an e-consent via SMS message link. Participants downloaded a customized study app to integrate surveys and data from study-supplied wireless blood pressure (BP) and 6 lead EKG sensors (Figure 1A). Participants completed pre- and post-study engagement surveys, weekly OAC adherence surveys, 4 study televisits, 4 ECG/BP readings, and 4 post-study surveys over a 6 month period. The primary endpoints were protocol engagement-based measurements that quantified percent completion of: 1) televisits 2) surveys, 3) ECG/BP readings requirements. Secondary endpoints were the % changes in: 1) OAC adherence (OACA), 2) nuisance bleeding (NB), 3) individual patient engagement surveys. Results 100 participants were recruited in 26 days (traditional: 6 in 2 weeks; social media: 94 in 12 days) with a dramatic surge in enrollment driven by social media ads (Figure 1B, Table). A recruitment overflow occurred with &amp;gt;200 eligible candidates on a waitlist. All key study completion metrics showed high compliance: televisit (91%); surveys (85%); ECG/BP completion (90%). Overall OACA was unchanged, but for subjects who reported low initial OACA, there was significant improvement at 6 months (85±16% to 98±6%; p=0.002). 47 participants (57%) reported NB, which did not correlate with OACA. Participant engagement measure scores (PAM-13) trended higher (baseline, 70%; 6 months, 74%, p=0.32). Lastly, study participants exhibited strong interest in participating in a larger experimental drug DCT study (90%) in the future. Conclusion The DeTAP study, conducted fully during the COVID-19 pandemic, demonstrates that a decentralized CV medical intervention trial is feasible and can achieve rapid recruitment, high study retention, physiologic and adverse event reporting, and high study engagement via the proper integration of digital technologies and a dedicated DCT study coordination effort. These findings could be informative for virtualizing large pivotal clinical trials at scale. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Bayer AG Figure 1. DeTAP Study Design and Recruitment TimelineTable 1. DeTAP Results

PSVIII-9 Genome assembly of American mink (Neovison vison) using high-fidelity long reads

Abstract Development of genome-enabled selection and providing new insights in the genetic architecture of economically important traits are essential parts of mink breeding programs. Availability of a contagious genome assembly would guarantee the fundamental genomic studies in American mink (Neovison vison). Advances in long-read sequencing technologies have provided the opportunity to obtain high quality and free-gaps assemblies for different species. The objective of this study was to generate an accurate genome assembly using Single Molecule High-Fidelity (HiFi) Sequencing for American mink. The whole genome sequences of 100 mink were analyzed to select the most homozygous individual. A black American mink from Millbank Fur Farm (Rockwood, ON, Canada) was selected for PacBio sequencing. The total number of 2,884,047 HiFi reads with the average size of 20 kb were generated using three libraries of PacBio Sequel II System. Three de novo assemblers including wtdbg, Flye and IPA were used to obtain the initial draft of assembly using the long reads. The draft generated using Flye was selected as the final assembly based on the metrics of contiguity and completeness. The final assembly included 3,529 contigs with the N50 of 18.26 Mb and the largest contig of 62.16 Mb. The length of genome assembly was 2.66 Gb with 85 gaps. These results confirmed that high-coverage and accurate long-reads significantly improved the American mink genome assembly and successfully generated more contagious assembly. The chromosome conformation capture data will be integrated to the current draft to obtain a chromosome-level genome assembly for American mink at the next step of the project.

Quantale-valued Cauchy tower spaces and completeness

Generalizing the concept of a probabilistic Cauchy space, we introduce quantale-valued Cauchy tower spaces. These spaces encompass quantale-valued metric spaces, quantale-valued uniform (convergence) tower spaces and quantale-valued convergence tower groups. For special choices of the quantale, classical and probabilistic metric spaces are covered and probabilistic and approach Cauchy spaces arise. We also study completeness and completion in this setting and establish a connection to the Cauchy completeness of a quantale-valued metric space.

The Effects of a Pandemic on Patient Engagement in a Patient-Reported Outcome Platform at Orthopaedic Sports Medicine Centers (106)

The Effects of a Pandemic on Patient Engagement in a Patient-Reported Outcome Platform at Orthopaedic Sports Medicine Centers (106)

The fabulous destiny of Richard Dedekind

By using the preliminary results given in a previous divulgative note, we present here a concise and self–contained introduction to the construction of the real field as the unique, up to increasing isomorphism, Dedekind complete totally ordered field. Moreover, we also show the equivalence between the Dedekind completeness property on totally ordered fields and some meaningful well–known notions present in the literature, such as the Cauchy completeness on totally ordered Archimedean fields. This characterization result allows us to correctly encode the Dedekind completeness for totally ordered fields in the general abstract setting of metric spaces. We believe that the essential parts of the paper can be easily accessed by anyone with some experience in abstract mathematical thinking. The paper completes the lecture given by the second author during the International Workshop on New Horizons in Teaching Science in Messina on June 2018.

On invariant linearization of Lie groupoids

The linearization theorem for proper Lie groupoids organizes and generalizes several results for classic geometries. Despite the various approaches and recent works on the subject, the problem of understanding invariant linearization remains somehow open. We address it here, by first giving a counter-example to a previous conjecture, and then proving a sufficient criterion that uses compatible complete metrics and covers the case of proper group actions. We also show a partial converse that fixes and extends previous results in the literature.

Development and field testing of a patient decision aid for management of acute Achilles tendon rupture: a study protocol

BackgroundAchilles tendon ruptures are common injuries in an otherwise healthy, active population. Several treatment options exist, with both surgical and non-surgical options. Each treatment option has a unique set of risks and harms, which may present patients with decisional conflict. The aim of the proposed study is to develop, alpha test and field test a patient decision aid for patients presenting with acute Achilles tendon ruptures.MethodsThis is a three-stage study protocol. First, we will assemble a multi-disciplinary steering group including patients, clinicians, educators, and researchers to develop the patient decision aid prototype using the Ottawa Decision Support Framework. Second, we will perform a mixed-methods alpha test of the decision aid prototype with patients and clinicians experienced in acute Achilles tendon ruptures. Outcomes measured will include acceptability and usability of the patient decision aid measured using validated outcome scales and semi-structured interviews. A minimum of three rounds of feedback will be obtained. Results will be analyzed using descriptive statistics, reviewed by the steering group, to guide revisions to decision aid prototype at each round. The third stage will be field testing the revised decision aid prototype in usual clinical care. A pre-/post-study will be performed with patients with acute Achilles tendon ruptures. Patients will be recruited from the emergency department and complete the pre-consultation decision aid prior to a one-week follow up with their surgeon. The primary outcome of field testing will be feasibility of implementing the decision aid in the clinical setting and will be measured with recruitment and completion metrics. Secondary outcomes include acceptability of the decision aid, knowledge, preparedness for decision making, and decisional conflict, measured using validated outcome measures. Statistical analysis will be performed using descriptive analysis for primary outcomes and a student t-test and Wilcoxon Rank-Sum test for secondary outcomes.DiscussionThis comprehensive study protocol outlines the development, alpha testing, and field testing of a patient decision aid for patients with acute Achilles tendon rupture. Systematic and transparent development and testing of patient decision aids is critical to improve decision aid quality.Trial registration Not Applicable.