705 research outputs found

    Octilinear Force-Directed Layout with Mental Map Preservation for Schematic Diagrams

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    We present an algorithm for automatically laying out metro map style schematics using a force-directed approach, where we use a localized version of the standard spring embedder forces combined with an octilinear magnetic force. The two types of forces used during layout are naturally conflicting, and the existing method of simply combining these to generate a resultant force does not give satisfactory results. Hence we vary the forces, emphasizing the standard forces in the beginning to produce a well distributed graph, with the octilinear forces becoming prevalent at the end of the layout, to ensure that the key requirement of line angles at intervals of 45? is obtained. Our method is considerably faster than the more commonly used search-based approaches, and we believe the results are superior to the previous force-directed approach. We have further developed this technique to address the issues of dynamic schematic layout. We use a Delaunay triangulation to construct a schematic “frame”, which is used to retain relative node positions and permits full control of the level of mental map preservation. This technique is the first to combine mental map preservation techniques with the additional layout criteria of schematic diagrams. To conclude, we present the results of a study to investigate the relationship between the level of mental map preservation and the user response time and accuracy

    Using Sifting for k-Layer Straightline Crossing Minimization

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    We present a new algorithm for k-layer straightline crossing minimization which is based on sifting that is a heuristic for dynamic reordering of decision diagrams used during logic synthesis and formal verification of logic circuits. The experiments prove sifting to be very efficient. In particular it outperforms the traditional layer by layer sweep based heuristics known from literature by far when applied to k-layered graphs with k \ge 3

    Bar 1-Visibility Drawings of 1-Planar Graphs

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    A bar 1-visibility drawing of a graph GG is a drawing of GG where each vertex is drawn as a horizontal line segment called a bar, each edge is drawn as a vertical line segment where the vertical line segment representing an edge must connect the horizontal line segments representing the end vertices and a vertical line segment corresponding to an edge intersects at most one bar which is not an end point of the edge. A graph GG is bar 1-visible if GG has a bar 1-visibility drawing. A graph GG is 1-planar if GG has a drawing in a 2-dimensional plane such that an edge crosses at most one other edge. In this paper we give linear-time algorithms to find bar 1-visibility drawings of diagonal grid graphs and maximal outer 1-planar graphs. We also show that recursive quadrangle 1-planar graphs and pseudo double wheel 1-planar graphs are bar 1-visible graphs.Comment: 15 pages, 9 figure

    Stress-Minimizing Orthogonal Layout of Data Flow Diagrams with Ports

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    We present a fundamentally different approach to orthogonal layout of data flow diagrams with ports. This is based on extending constrained stress majorization to cater for ports and flow layout. Because we are minimizing stress we are able to better display global structure, as measured by several criteria such as stress, edge-length variance, and aspect ratio. Compared to the layered approach, our layouts tend to exhibit symmetries, and eliminate inter-layer whitespace, making the diagrams more compact

    The quality of Australian Indigenous primary health care research focusing on social and emotional wellbeing: a systematic review

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    Objectives and importance of the study: Primary health care research focused on Aboriginal and Torres Strait Islander (Indigenous) people is needed to ensure that key frontline services provide evidence based and culturally appropriate care. We systematically reviewed the published primary health care literature to identify research designs, processes and outcomes, and assess the scientific quality of research focused on social and emotional wellbeing. This will inform future research to improve evidence based, culturally appropriate primary health care. Systematic review in accordance with PRISMA and MOOSE guidelines. Four databases and one Indigenous-specific project website were searched for qualitative, quantitative and mixed-method published research. Studies that were conducted in primary health care services and focused on the social and emotional wellbeing of Indigenous people were included. Scientific quality was assessed using risk-of-bias assessment tools that were modified to meet our aims. We assessed community acceptance by identifying the involvement of community governance structures and representation during research development, conduct and reporting. Data were extracted using standard forms developed for this review. We included 32 articles, which reported on 25 studies. Qualitative and mixed methods were used in 18 studies. Twelve articles were judged as high or unclear risk of bias, four as moderate and five as low risk of bias. Another four studies were not able to be assessed as they did not align with the risk-of-bias tools. Of the five articles judged as low risk of bias, two also had high community acceptance and both of these were qualitative. One used a phenomenological approach and the other combined participatory action research with a social-ecological perspective and incorporated 'two-way learning' principles. Of the 16 studies where a primary outcome was identified, eight aimed to identify perceptions or experiences. The remaining studies assessed resources, or evaluated services, interventions, programs or policies. We were unable to identify primary outcomes in eight studies. Conducting Indigenous-focused primary health care research that is scientifically robust, culturally appropriate and produces community-level outcomes is challenging. We suggest that research teams use participatory, culturally sensitive approaches and collaborate closely to plan and implement high-quality research that incorporates local perspectives. Research should result in beneficial outcomes for the communities involved

    Advances in C-Planarity Testing of Clustered Graphs

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    A clustered graph C=(G,T) consists of an undirected graph G and a rooted tree T in which the leaves of T correspond to the vertices of G=(V,E). Each vertex c in T corresponds to a subset of the vertices of the graph called ''cluster''. C-planarity is a natural extension of graph planarity for clustered graphs, and plays an important role in automatic graph drawing. The complexity status of c-planarity testing is unknown. It has been shown that c-planarity can be tested in linear time for c-connected graphs, i.e., graphs in which the cluster induced subgraphs are connected. In this paper, we provide a polynomial time algorithm for c-planarity testing for "almost" c-connected clustered graphs, i.e., graphs for which all c-vertices corresponding to the non-c-connected clusters lie on the same path in T starting at the root of T, or graphs in which for each non-connected cluster its super-cluster and all its siblings are connected. The algorithm uses ideas of the algorithm for subgraph induced planar connectivity augmentation. We regard it as a first step towards general c-planarity testing

    A Generalization of the Directed Graph Layering Problem

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    The Directed Layering Problem (DLP) solves a step of the widely used layer-based layout approach to automatically draw directed acyclic graphs. To cater for cyclic graphs, classically a preprocessing step is used that solves the Feedback Arc Set Problem (FASP)to make the graph acyclic before a layering is determined. Here, we present the Generalized Layering Problem (GLP) which solves the combination of DLP and FASP simultaneously, allowing general graphs as input. We show GLP to be NP- complete, present integer programming models to solve it, and perform thorough evaluations on different sets of graphs and with different implementations for the steps of the layer- based approach. We observe that GLP reduces the number of dummy nodes significantly, can produce more compact drawings and improves on graphs where DLP yields poor aspect ratios

    Identification of patients with atrial fibrillation in UK community pharmacy: an evaluation of a new service

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    Background: Many patients with atrial fibrillation (AF) are asymptomatic and diagnosed via opportunistic screening. Community pharmacy has been advocated as a potential resource for opportunistic screening and lifestyle interventions.  Objective: The objective of this evaluation is to describe the outcomes from an AF service, in terms of referrals and interventions provided to patients identified as not at risk.  Method: Eligibility was assessed from pharmacy records and the completion of a short questionnaire. Once consented, patients were screened for AF and their blood pressure was measured.  Results: Of 594 patients screened, nine were identified as at risk of having AF and were referred to their GP. The service also identified 109 patients with undiagnosed hypertension, 176 patients with a Body Mass Index (BMI) > 30, 131 with an Audit-C score > 5 and 59 smokers. Pharmacists provided 413 interventions in 326 patients aimed at weight reduction (239), alcohol consumption (123) and smoking cessation (51).  Conclusion: This evaluation characterises the interventions provided to, not only those identified with the target condition - in this case AF - but also those without it. The true outcome of these additional interventions, along with appropriate follow-up, should be the focus of future studies.Impact of findings on patients or practice •Patients are willing to be screened for AF through community pharmacies•Screening can provide opportunities to identify other healthcare problems such a hypertension or poor lifestyle •Community pharmacists are able to provide brief advice to patients as a result of this opportunistic screenin

    Implementing Kanyini GAP, a pragmatic randomised controlled trial in Australia: Findings from a qualitative study

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    © 2015 Liu et al. Background: Pragmatic randomised controlled trials (PRCTs) aim to assess intervention effectiveness by accounting for 'real life' implementation challenges in routine practice. The methodological challenges of PRCT implementation, particularly in primary care, are not well understood. The Kanyini Guidelines Adherence to Polypill study (Kanyini GAP) was a recent primary care PRCT involving multiple private general practices, Indigenous community controlled health services and private community pharmacies. Through the experiences of Kanyini GAP participants, and using data from study materials, this paper identifies the critical enablers and barriers to implementing a PRCT across diverse practice settings and makes recommendations for future PRCT implementation. Methods: Qualitative data from 94 semi-structured interviews (47 healthcare providers (pharmacists, general practitioners, Aboriginal health workers; 47 patients) conducted for the process evaluation of Kanyini GAP was used. Data coded to 'trial impact', 'research motivation' and 'real world' were explored and triangulated with data extracted from study materials (e.g. Emails, memoranda of understanding and financial statements). Results: PRCT implementation was facilitated by an extensive process of relationship building at the trial outset including building on existing relationships between core investigators and service providers. Health providers' and participants' altruism, increased professional satisfaction, collaboration, research capacity and opportunities for improved patient care enabled implementation. Inadequate research infrastructure, excessive administrative demands, insufficient numbers of adequately trained staff and the potential financial impact on private practice were considered implementation barriers. These were largely related to this being the first experience of trial involvement for many sites. The significant costs of addressing these barriers drew study resources from the task of achieving recruitment targets. Conclusions: Conducting PRCTs is crucial to generating credible evidence of intervention effectiveness in routine practice. PRCT implementation needs to account for the particular challenges of implementing collaborative research across diverse stakeholder organisations. Reliance on goodwill to participate is crucial at the outset. However, participation costs, particularly for organisations with little or no research experience, can be substantial and should be factored into PRCT funding models. Investment in a pool to fund infrastructure in the form of primary health research networks will offset some of these costs, enabling future studies to be implemented more cost-effectively. Trial registration:ACTRN12608000583334

    A generic algorithm for layout of biological networks

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    BackgroundBiological networks are widely used to represent processes in biological systems and to capture interactions and dependencies between biological entities. Their size and complexity is steadily increasing due to the ongoing growth of knowledge in the life sciences. To aid understanding of biological networks several algorithms for laying out and graphically representing networks and network analysis results have been developed. However, current algorithms are specialized to particular layout styles and therefore different algorithms are required for each kind of network and/or style of layout. This increases implementation effort and means that new algorithms must be developed for new layout styles. Furthermore, additional effort is necessary to compose different layout conventions in the same diagram. Also the user cannot usually customize the placement of nodes to tailor the layout to their particular need or task and there is little support for interactive network exploration.ResultsWe present a novel algorithm to visualize different biological networks and network analysis results in meaningful ways depending on network types and analysis outcome. Our method is based on constrained graph layout and we demonstrate how it can handle the drawing conventions used in biological networks.ConclusionThe presented algorithm offers the ability to produce many of the fundamental popular drawing styles while allowing the exibility of constraints to further tailor these layouts.publishe
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