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Search Results: 1 - 10 of 4669 matches for " Julia Padberg "
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A Survey of Control Structures for Reconfigurable Petri Nets  [PDF]
Julia Padberg, Kathrin Hoffmann
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.32002
Abstract: Software systems are increasingly executed in dynamic infrastructures. These infrastructures are dynamic as they are themselves subject to change as they support various applications that may or may not share some of the resources. Dynamic software systems become more and more important, but are difficult to handle. Modeling and simulating dynamic systems requires the representation of their processes and the system changes within one model. To that effect, reconfigurable Petri nets consist of a Petri net and a set of rules that can modify the Petri net. Their main feature is the capability to model complex coordination behavior in dynamically adapting infrastructures. The interplay of both levels of dynamic behavior requires a very precise description, so the specification when and which rules are to be applied plays a crucial role for the convenient use of reconfigurable nets. We differentiate several types of reconfigurable Petri nets and present a survey of control structure for these types, reconfigurable Petri nets. These control structures either concern the infrastructure, i.e., the rules and transformations or the system part, i.e., the firing behavior, or both. They are introduced by a short characterization and illustrated by examples. We state the results for various Petri net types and the tools supporting the different control structures.
Reconfigurable Decorated PT Nets with Inhibitor Arcs and Transition Priorities
Julia Padberg
Computer Science , 2014,
Abstract: In this paper we deal with additional control structures for decorated PT Nets. The main contribution are inhibitor arcs and priorities. The first ensure that a marking can inhibit the firing of a transition. Inhibitor arcs force that the transition may only fire when the place is empty. an order of transitions restrict the firing, so that an transition may fire only if it has the highest priority of all enabled transitions. This concept is shown to be compatible with reconfigurable Petri nets.
A rough-and-ready cluster-based approach for extracting finite-time coherent sets from sparse and incomplete trajectory data
Gary Froyland,Kathrin Padberg-Gehle
Mathematics , 2015,
Abstract: We present a numerical method to identify regions of phase space that are approximately retained in a mobile compact neighbourhood over a finite time duration. Our approach is based on spatio-temporal clustering of trajectory data. The main advantages of the approach are the ability to produce useful results (i) when there are relatively few trajectories and (ii) when there are gaps in observation of the trajectories as can occur with real data. The method is easy to implement, works in any dimension, and is fast to run.
Nonautonomous control of stable and unstable manifolds in two-dimensional flows
Sanjeeva Balasuriya,Kathrin Padberg-Gehle
Mathematics , 2013, DOI: 10.1016/j.physd.2014.03.003
Abstract: We outline a method for controlling the location of stable and unstable manifolds in the following sense. From a known location of the stable and unstable manifolds in a steady two-dimensional flow, the primary segments of the manifolds are to be moved to a user-specified time-varying location which is near the steady location. We determine the nonautonomous perturbation to the vector field required to achieve this control, and give a theoretical bound for the error in the manifolds resulting from applying this control. The efficacy of the control strategy is illustrated via a numerical example.
The cytokine hypothesis: A neurodevelopmental explanation for the emergence of schizophrenia later in life  [PDF]
Julia Howard
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.48A2011
Abstract:

There is increasing evidence for the cytokine hypothesis, which states that exposure to elevated cytokines in utero due to maternal immune activation is a major risk factor for the development of schizophrenia later in life. This is supported by numerous epidemicologic studies that connect multiple infections with schizophrenia emergence. Furthermore, cytokines are critically involved in early neurodevelopment and deviations from the norm can result in abnormal neuroanatomy and brain chemistry. Animal models of schizophrenia also support the critical role of developmental neuroinflammation in predisposing the brain to anatomical and behavioral abnormalities. Although there is strong evidence for the critical role of cytokines, they most likely work with other contributing risk factors such as genetic predisposition. New evidence indicates that cytokine exposure in utero may prime the brain and that a second stressor during adolescence, referred to as a second hit, may activate existing developmental vulnerabilities resulting in the emergence of clinical schizophrenia. Further knowledge of these pathogenic processes and risk factors could be very instrumental in reducing risk and slowing emergence of schizophrenia.

Seasonal variability of the subpolar gyres in the Southern Ocean: a numerical investigation based on transfer operators
M. Dellnitz,G. Froyland,C. Horenkamp,K. Padberg-Gehle
Nonlinear Processes in Geophysics (NPG) , 2009,
Abstract: The detection of regions in the ocean that are coherent over an extended period of time is a fundamental problem in many oceanic applications. For instance such regions are important for studying the transport of marine species and for the distribution of nutrients. In this study we demonstrate the efficacy of transfer operators in detecting and analysing such structures. We focus first on the detection of the Weddell and Ross Gyre for the four seasons spanning December 2003–November 2004 within the 3-D oceanic domain south of 30° S, and show distinct seasonal differences in both the three-dimensional structure and the persistence of the gyres. Further, we demonstrate a new technique based on the discretised transfer operators to calculate the mean residence time of water within parts of the gyres and determine pathways of water leaving and entering the gyres.
How to React to the Subprime Crisis? - The Impact of an Interest Rate Freeze on Residential Mortgage Backed  [PDF]
Julia Hein, Thomas Weber
Journal of Service Science and Management (JSSM) , 2009, DOI: 10.4236/jssm.2009.24035
Abstract: Several policy options have been discussed to mitigate the current subprime mortgage crisis. This paper analyses an interest rate freeze on adjustable rate mortgages as one possible reaction. In particular, the implications on Residential Mortgage Backed Securities (RMBS) are studied. We examine shifts in the underlying portfolio’s discounted cash flow distributions as well as changes in the payment profile of RMBS-tranches. We show that the positive effects of a rate freeze, e.g. less foreclosures and a stabilizing housing market, can outweigh the negative effect of lower interest income such that investors might be better off.
Dynamic Activity-Related Incentives for Physical Activity  [PDF]
Julia Schuler, Sibylle Brunner
Advances in Physical Education (APE) , 2012, DOI: 10.4236/ape.2012.21001
Abstract: The present studies adopted the theoretical framework of activity- and purpose-related incentives (Rheinberg, 2008) to explain the maintenance of physical activity. We hypothesized that activity-related incentives (e.g., “fun”) increase more than purpose-related incentives (e.g., “health”) between the initiation and maintenance phase of physical activity. Additionally, change in activity-related incentives was hypothesized to be a better predictor of maintenance of physical activity than change in purpose-related incentives. Two correlative field studies with rehabilitation patients (Study 1) and Nordic Walkers (Study 2) were conducted to test the hypotheses. Participants’ incentives of physical activity were measured at the beginning of exercising and two weeks (Study 1; T2) and three months (Study 2; T2) later. At T2, participants were asked for their current physical activity. Both studies showed a greater change of activity-related incentives than purpose-related incentives. Furthermore, change in activity-related incentives was more predictive of the maintenance of physical activity than change in purpose-related incentives. The results showed the important role of activity-related incentives in maintenance of physical activity. The theoretical contribution to physical activity maintenance research and practical implications for health promotion programs were discussed.
Raising a Child with Down Syndrome: Do Preferred Coping Strategies Explain Differences in Parental Health?  [PDF]
Tatjana Alexander, Julia Walendzik
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.71005
Abstract: The aim of this study was to determine coping strategies which may represent important personal resources and have a buffering effect in preventing mental health problems in parents of children with Down syndrome. Forty-nine parents of children with Down syndrome completed self-administrated measures of psychological and physical health problems, and coping behaviour, using several established measuring instruments. According to the hierarchical regression analyses, parents who often used regenerative coping strategies, and who experienced positive personal changes in terms of posttraumatic growth suffered from less anxiety and somatisation symptoms, whereas dysfunctional coping was the best predictor for parental depression and physical symptoms. Regenerative coping mediated between parental tendency to recognize their emotional needs and somatisation symptoms. Intervention programs for families of children with Down syndrome may benefit if they address parents’ reflection about their feelings, foster posttraumatic growth processes, and impart knowledge about long-term regenerative coping strategies.
Effect of aerobic exercise training and cognitive behavioural therapy on reduction of chronic fatigue in patients with facioscapulohumeral dystrophy: protocol of the FACTS-2-FSHD trial
Nicoline BM Voet, Gijs Bleijenberg, George W Padberg, Baziel GM van Engelen, Alexander CH Geurts
BMC Neurology , 2010, DOI: 10.1186/1471-2377-10-56
Abstract: A multi-centre, assessor-blinded, randomized controlled trial is conducted. A sample of 75 FSHD patients with severe chronic fatigue (CIS-fatigue ≥ 35) will be recruited and randomized to one of three groups: (1) AET + usual care, (2) CBT + usual care or (3) usual care alone, which consists of no therapy at all or occasional (conventional) physical therapy. After an intervention period of 16 weeks and a follow-up of 3 months, the third (control) group will as yet be randomized to either AET or CBT (approximately 7 months after inclusion). Outcomes will be assessed at baseline, immediately post intervention and at 3 and 6 months follow up.The FACTS-2-FSHD study is the first theory-based randomized clinical trial which evaluates the effect and the maintenance of effects of AET and CBT on the reduction of chronic fatigue in patients with FSHD. The interventions are based on a theoretical model of chronic fatigue in patients with FSHD. The study will provide a unique set of data with which the relationships between outcome measures at all levels of the ICF could be assessed.Dutch Trial Register, NTR1447.Facioscapulohumeral dystrophy (FSHD) is the third most common inherited neuromuscular disorder. It is an autosomal dominant slowly progressive myopathy with a variable age of onset, mostly in the second or third decade of life. Its yearly incidence rate is approximately 1:20.000 [1]. The disease primarily affects the facial muscles, the muscles of the shoulder girdle (most typically the scapula stabilizers) and various leg muscles, while pelvic and trunk muscles are eventually affected as well [2-4]. The pattern of muscle weakness is often asymmetrical, and the rate and extent of progression may vary considerably with sudden periods of unexplained rapid disease progression. In a small percentage of the patients, even respiratory insufficiency may occur [5]. Only very recently, evidence became available that there may be a selective involvement of the central nervous syst
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