1,748 research outputs found
Personale Dienstleistungen durch Soziale Landwirtschaft. Ein Definitionsansatz.
In diesem Paper soll zum einen der aktuelle Forschungsstand und zum anderen der weitere Forschungsplan der Autorin zum Thema „soziale Dienstleistungen durch landwirtschaftliche Unternehmen“ für die Diskussion mit Wissenschaft und Praxis vorgestellt werden. Als Kern des aktuellen Forschungsstandes wird eine grundlegende Definition und Systematisierung des Begriffes „Soziale Dienstleistungen durch landwirtschaftliche Unternehmen“ präsentiert. Soziale Dienstleistungen durch landwirtschaftliche Unternehmen sind Angebote aus den Bereichen Pädagogik, Therapie, Beschäftigung oder Lebensgestaltung zum Zweck der Integration von Menschen. Außerdem werden weiterführende Untersuchungsschritte formuliert, die u.a. als Folge der demographischen Entwicklung in Deutschland die genauere Betrachtung der Zielgruppe Senioren beinhalten
Public Transit Labeling
We study the journey planning problem in public transit networks. Developing
efficient preprocessing-based speedup techniques for this problem has been
challenging: current approaches either require massive preprocessing effort or
provide limited speedups. Leveraging recent advances in Hub Labeling, the
fastest algorithm for road networks, we revisit the well-known time-expanded
model for public transit. Exploiting domain-specific properties, we provide
simple and efficient algorithms for the earliest arrival, profile, and
multicriteria problems, with queries that are orders of magnitude faster than
the state of the art.Comment: An extended abstract of this paper has been accepted at the 14th
International Symposium on Experimental Algorithms (SEA'15
Transit Node Routing Reconsidered
Transit Node Routing (TNR) is a fast and exact distance oracle for road
networks. We show several new results for TNR. First, we give a surprisingly
simple implementation fully based on Contraction Hierarchies that speeds up
preprocessing by an order of magnitude approaching the time for just finding a
CH (which alone has two orders of magnitude larger query time). We also develop
a very effective purely graph theoretical locality filter without any
compromise in query times. Finally, we show that a specialization to the online
many-to-one (or one-to-many) shortest path further speeds up query time by an
order of magnitude. This variant even has better query time than the fastest
known previous methods which need much more space.Comment: 19 pages, submitted to SEA'201
Core Routing on Dynamic Time-Dependent Road Networks
Route planning in large scale time-dependent road networks is an important practical application of the shortest paths problem that greatly benefits from speedup techniques. In this paper we extend a two-level hierarchical approach for pointto-point shortest paths computations to the time-dependent case. This method, also known as core routing in the literature for static graphs, consists in the selection of a small subnetwork where most of the computations can be carried out, thus reducing the search space. We combine this approach with bidirectional goal-directed search in order to obtain an algorithm capable of finding shortest paths in a matter of milliseconds on continental sized networks. Moreover, we tackle the dynamic scenario where the piecewise linear functions that we use to model time-dependent arc costs are not fixed, but can have their coefficients updated requiring only a small computational effort
Automated and Interpretable Patient ECG Profiles for Disease Detection, Tracking, and Discovery
The electrocardiogram or ECG has been in use for over 100 years and remains
the most widely performed diagnostic test to characterize cardiac structure and
electrical activity. We hypothesized that parallel advances in computing power,
innovations in machine learning algorithms, and availability of large-scale
digitized ECG data would enable extending the utility of the ECG beyond its
current limitations, while at the same time preserving interpretability, which
is fundamental to medical decision-making. We identified 36,186 ECGs from the
UCSF database that were 1) in normal sinus rhythm and 2) would enable training
of specific models for estimation of cardiac structure or function or detection
of disease. We derived a novel model for ECG segmentation using convolutional
neural networks (CNN) and Hidden Markov Models (HMM) and evaluated its output
by comparing electrical interval estimates to 141,864 measurements from the
clinical workflow. We built a 725-element patient-level ECG profile using
downsampled segmentation data and trained machine learning models to estimate
left ventricular mass, left atrial volume, mitral annulus e' and to detect and
track four diseases: pulmonary arterial hypertension (PAH), hypertrophic
cardiomyopathy (HCM), cardiac amyloid (CA), and mitral valve prolapse (MVP).
CNN-HMM derived ECG segmentation agreed with clinical estimates, with median
absolute deviations (MAD) as a fraction of observed value of 0.6% for heart
rate and 4% for QT interval. Patient-level ECG profiles enabled quantitative
estimates of left ventricular and mitral annulus e' velocity with good
discrimination in binary classification models of left ventricular hypertrophy
and diastolic function. Models for disease detection ranged from AUROC of 0.94
to 0.77 for MVP. Top-ranked variables for all models included known ECG
characteristics along with novel predictors of these traits/diseases.Comment: 13 pages, 6 figures, 1 Table + Supplemen
Dynamic Arc-Flags in Road Networks
International audienceIn this work we introduce a new data structure, named Road-Signs, which allows us to efficiently update the Arc-Flags of a graph in a dynamic scenario. Road-Signs can be used to compute Arc-Flags, can be efficiently updated and do not require large space consumption for many real-world graphs like, e.g., graphs arising from road networks. In detail, we define an algorithm to preprocess Road-Signs and an algorithm to update them each time that a weight increase operation occurs on an edge of the network. We also experimentally analyze the proposed algorithms in real-world road networks showing that they yields a significant speed-up in the updating phase of Arc-Flags, at the cost of a very small space and time overhead in the preprocessing phase
Arc-Flags in Dynamic Graphs
Computation of quickest paths has undergoing a rapid development in recent
years. It turns out that many high-performance route planning algorithms are
made up of several basic ingredients. However, not all of those ingredients have
been analyzed in a emph{dynamic} scenario where edge weights change after
preprocessing. In this work, we present how one of those ingredients, i.e.,
Arc-Flags can be applied in dynamic scenario
Trip-Based Public Transit Routing
We study the problem of computing all Pareto-optimal journeys in a public
transit network regarding the two criteria of arrival time and number of
transfers taken. We take a novel approach, focusing on trips and transfers
between them, allowing fine-grained modeling. Our experiments on the
metropolitan network of London show that the algorithm computes full 24-hour
profiles in 70 ms after a preprocessing phase of 30 s, allowing fast queries in
dynamic scenarios.Comment: Minor corrections, no substantial changes. To be presented at ESA
201
- …
