16 research outputs found

    Analysis of Inter-Chip Communication Patterns on Multi-Core Distributed Shared-Memory Computers

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    Multi-core multi-socket distributed shared-memory com- puters (DSM computers, for short) have become an impor- tant node architecture in scientific computing as they provide substantial computational capacity with relatively low space and power requirements. Compared to conventional computer networks, inter-chip networks used in DSM computers feature higher bandwidth, lower latency and tighter integration with the CPU. The inter-chip network is a shared resource among the user application and many other services, which can lead to consid- erable variation of execution times of identical communication tasks. In this work, we explore traffic patterns resulting from MPI collective communication primitives and investigate the ques- tion whether inter-chip link load is a reliable indicator and predictor for the execution time of collective communication primitives on a DSM computer. Our experiments on a Sun Fire X4600 M2 DSM computer with 32 cores (eight quad-core CPUs) indicate that specific single link loads are positively correlated with the execution time of MPI ALLREDUCE. Ob- serving patterns over multiple links allows refinement of the single-link observation

    Impact of the COVID-19 pandemic on children with and without affective dysregulation and their families

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    Analyzing COVID-19-related stress in children with affective dysregulation (AD) seems especially interesting, as these children typically show heightened reactivity to potential stressors and an increased use of maladaptive emotion regulation strategies. Children in out-of-home care often show similar characteristics to those with AD. Since COVID-19 has led to interruptions in psychotherapy for children with mental health problems and to potentially reduced resources to implement treatment strategies in daily life in families or in out-of-home care, these children might show a particularly strong increase in stress levels. In this study, 512 families of children without AD and 269 families of children with AD reported on COVID-19-related stress. The sample comprised screened community, clinical, and out-of-home care samples. Sociodemographic factors, characteristics of child and caregiver before the pandemic, and perceived change in external conditions due to the pandemic were examined as potential risk or protective factors. Interestingly, only small differences emerged between families of children with and without AD or between subsamples: families of children with AD and families in out-of-home care were affected slightly more, but in few domains. Improvements and deteriorations in treatment-related effects balanced each other out. Overall, the most stable and strongest risk factor for COVID-19-related stress was perceived negative change in external conditions—particularly family conditions and leisure options. Additionally, caregiver characteristics emerged as risk factors across most models. Actions to support families during the pandemic should, therefore, facilitate external conditions and focus on caregiver characteristic to reduce familial COVID-19-related stress. Trial registration: German Clinical Trials Register (DRKS), ADOPT Online: DRKS00014963 registered 27 June 2018, ADOPT Treatment: DRKS00013317 registered 27 September 2018, ADOPT Institution: DRKS00014581 registered 04 July 2018

    Holistic Biquadratic IIR Filter Design for Communication Systems Using Differential Evolution

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    Digital IIR filter implementations are important building blocks of most communication systems. The chosen number format (fixed-point, floating-point; precision) has a major impact on achievable performance and implementation cost. Typically, filter design for communication systems is based on filter specifications in the frequency domain. We consider IIR filter design as an integral part of communication system optimisation with implicit filter specification in the time domain (via symbol/bit error rate). We present a holistic design flow with the system's bit error rate as the main objective. We consider a discrete search space spanned by the quantised filter coefficients. Differential Evolution is used for efficient sampling of this huge finite design space. We present communication system performance (based on bit-true simulations) and both measured and estimated receiver IIR chip areas. The results show that very small number formats are acceptable for complex filters and that the choice between fixed-point and floating-point number formats is nontrivial if precision is a free parameter

    Bayesian Hierarchical Modelling for Uncertainty Quantification in Operational Thermal Resistance of LED Systems

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    Remaining useful life (RUL) prediction is central to prognostics and reliability assessment of light-emitting diode (LED) systems. Their unknown long-term service life remaining when subject to specific operating conditions is affected by various sources of uncertainty stemming from production of individual system components, application of the whole system, measurement and operation. To enhance the reliability of model-based predictions, it is essential to account for all of these uncertainties in a systematic manner. This paper proposes a Bayesian hierarchical modelling framework for inverse uncertainty quantification (UQ) in LED operation under thermal loading. The main focus is on the LED systems’ operational thermal resistances, which are subject to system and application variability. Posterior inference is based on a Markov chain Monte Carlo (MCMC) sampling scheme using the Metropolis–Hastings (MH) algorithm. Performance of the method is investigated for simulated data, which allow to focus on different UQ aspects in applications. Findings from an application scenario in which the impact of disregarded uncertainty on RUL prediction is discussed highlight the need for a comprehensive UQ to allow for reliable predictions

    Compressed Hierarchical Representations for Multi-Task Learning and Task Clustering

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    In this paper, we frame homogeneous-feature multi-task learning (MTL) as a hierarchical representation learning problem, with one task-agnostic and multiple task-specific latent representations. Drawing inspiration from the information bottleneck principle and assuming an additive independent noise model between the task-agnostic and task-specific latent representations, we limit the information contained in each task-specific representation. It is shown that our resulting representations yield competitive performance for several MTL benchmarks. Furthermore, for certain setups, we show that the trained parameters of the additive noise model are closely related to the similarity of different tasks. This indicates that our approach yields a task-agnostic representation that is disentangled in the sense that its individual dimensions may be interpretable from a task-specific perspective.Comment: Accepted by the 2022 International Joint Conference on Neural Networks (IJCNN 2022

    Electron delocalization in vinyl ruthenium substituted cyclophanes:Assessment of the through-space and the through-bond pathways

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    Pseudopara[2.2]paracyclophane- and [2.1]orthocyclophane-bridged diruthenium complexes 2 and 3 with two interlinked electroactive styryl ruthenium moieties have been prepared and investigated. Both complexes undergo two reversible consecutive one-electron oxidation processes which are separated by 270 or 105 mV. Stepwise electrolysis of the neutral complexes to first the mixed-valent radical cations and then the dioxidized dications under IR monitoring reveal incremental shifts of the charge-sensitive Ru(CO) bands and allow for an assignment of their radical cations as moderately or very weakly coupled mixed-valent systems of class II according to Robin and Day. Ground-state delocalization in the mixed-valent forms of these complexes as based on the CO band shifts is considerably larger for the “closed” paracyclophane as for the “half-open” orthocyclophane. Experimental findings are backed by the calculated IR band patterns and spin density distributions for radical cations of slightly simplified model complexes 2Me•+ and 3Me•+ with the PiPr3 ligands replaced by PMe3. Radical cations 2•+ and 3•+ feature a characteristic NIR band that is neither present in their neutral or fully oxidized forms nor in the radical cation of the monoruthenium[2.2]paracyclophane complex 1 with just one vinyl ruthenium moiety. These bands are thus assigned as intervalence charge transfer (IVCT) transitions. Our results indicate that electronic coupling “through space”, via the stacked styrene decks, is significantly more efficient than the “through-bond” pathway

    Exploring Temperature-Modulated Operation Mode of Metal Oxide Gas Sensors for Robust Signal Processing

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    Metal oxide (MOx) gas sensor signals are mainly governed by adsorption and desorption processes of oxygen and its reaction with surrounding gas molecules. Different target gases exhibit different reaction rates leading to characteristic sensor responses for specific gas species and their concentrations. In this work, we compare temperature-modulated sensor operation (TMO) with sensor operation at a single temperature. Further, we explore if under specific TMO regimes, a simple signal processing allows for quantification of gas concentrations. We specifically investigate, if the relevant information can be captured in selected discrete wavelet coefficients. In addition, we compare the results received from this wavelet features to reaction rate evaluation features

    Guideline adherence in German routine care of children and adolescents with ADHD: an observational study

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    Although guidelines for the assessment and treatment of mental disorders in childhood and adolescence have been available in Germany for several years, there are barely any data on adherence to guidelines in national routine care. Therefore, the study aimed at a nationwide evaluation of guideline adherence (GA) for the assessment and treatment of children and adolescents with attention-deficit/hyperactivity disorder (ADHD) in German routine care in various groups of health care providers (HCPs). Besides a detailed description of GA, the study focused on examining possible differences between professional groups. Furthermore, data based on global self-reports of clinicians were compared with ratings of documented care in individual patients. Protocols of 73 clinicians regarding their handling of ADHD in routine care for 167 patients were rated according to German guideline recommendations for ADHD care. GA was measured as the proportion of components fulfilled in each individual patient as documented by the HCP. The results were compared to a preceding interview with clinicians regarding their GA. Multilevel models were constructed to detect differences in GA between professional groups. Based on mandatory guideline components, adherence rates of 38.9-72.7% were found and classified as moderate (33.3% < GA <= 66.6%) to high (GA > 66.6%). The comparison of the GA between the professional groups generally yielded only small differences. Correlations between GA reported globally by the HCPs and GA documented and rated for individual cases were low. Overall, most rates of GA for ADHD in German routine care lay within a moderate range. Targets for enhancement of GA may be the involvement of teachers and schools in the treatment process, the implementation of psychoeducational methods in general, as well as a careful examination of patients, including monitoring of treatment effects during titration trials. The development of further strategies to monitor the quality of ADHD routine care is needed

    CCDC 848048: Experimental Crystal Structure Determination

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    Related Article: P.Mucke, M.Zabel, R.Edge, D.Collison, S.Clement, S.Zalis, R.F.Winter|2011|J.Organomet.Chem.|696|3186|doi:10.1016/j.jorganchem.2011.06.02

    In Situ Assembly of Platinum (II)-Metallopeptide Nanostructures Inhibits Energy Homeostasis and Cellular Metabolism

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    Nanostructure-based functions are omnipresent in nature and essential for the diversity of life. Unlike small molecules, which are often inhibitors of enzymes or biomimetics with established methods of elucidation, we show that functions of nanoscale structures in cells are complex and can implicate system-level effects such as the regulation of energy and redox homeostasis. Herein, we design a platinum (II) containing tripeptide that assembles into intracellular fibrillar nanostructures upon molecular rearrangement in the presence of endogenous H2O2. The formed nanostructures blocked metabolic functions, including aerobic glycolysis and oxidative phosphorylation, thereby shutting down ATP production. As a consequence, ATP-dependent actin formation and glucose metabolite- dependent histone deacetylase activity are downregulated. We demonstrate that assembly-driven nanomaterials offer a rich avenue to achieve broad-spectrum bioactivities that could provide new opportunities in drug discovery
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