Implementation and performance analysis of a QoS-aware TFRC mechanism

This paper deals with the improvement of transport protocol behaviour over the DiffServ Assured Forwarding (AF)class. The Assured Service (AS) provides a minimum throughput guarantee that classical congestion control mechanisms, like window-based in TCP or equation-based in TCP-Friendly Rate Control (TFRC), are not able to use efficiently. In response, this paper proposes a performance analysis of a QoS aware congestion control mechanism, named gTFRC, which improves the delivery of continuous streams. The gTFRC (guaranteed TFRC) mechanism has been integrated into an Enhanced Transport Protocol (ETP) that allows protocol mechanisms to be dynamically managed and controlled. After comparing a ns-2 simulation and our implementation of the basic TFRC mechanism, we show that ETP/gTFRC extension is able to reach a minimum throughput guarantee whatever the flow’s RTT and target rate (TR) and the network provisioning conditions

Virtualizing the access network via open APIs

Residential broadband consumption is growing rapidly, in-creasing the gap between ISP costs and revenues. Mean-while, proliferation of Internet-enabled devices is congesting access networks, frustrating end-users and content providers. We propose that ISPs virtualize access infrastructure, using open APIs supported through SDN, to enable dynamic and controlled sharing amongst user streams. Content providers can programmatically provision capacity to user devices to ensure quality of experience, users can match the degree of virtualization to their usage pattern, and ISPs can real-ize per-stream revenues by slicing their network resources. Using video streaming and bulk transfers as examples, we develop an architecture that specifies the interfaces between the ISP, content provider, and user. We propose an algo-rithm for optimally allocating network resources, leveraging bulk transfer time elasticity and access path space diver-sity. Simulations using real traces show that virtualization can reduce video degradation by over 50%, for little extra bulk transfer delay. Lastly, we prototype our system and validate it in a test-bed with real video streaming and file transfers. Our proposal is a first step towards the long-term goal of realizing open and agile access network service quality management that is acceptable to users, ISPs and content providers alike

Dynamic physiological alpha-synuclein S129 phosphorylation is driven by neuronal activity

In Parkinson’s disease and other synucleinopathies, the elevation of α-synuclein phosphorylated at Serine129 (pS129) is a widely cited marker of pathology. However, the physiological role for pS129 has remained undefined. Here we use multiple approaches to show for the first time that pS129 functions as a physiological regulator of neuronal activity. Neuronal activity triggers a sustained increase of pS129 in cultured neurons (200% within 4 h). In accord, brain pS129 is elevated in environmentally enriched mice exhibiting enhanced long-term potentiation. Activity-dependent α-synuclein phosphorylation is S129-specific, reversible, confers no cytotoxicity, and accumulates at synapsin-containing presynaptic boutons. Mechanistically, our findings are consistent with a model in which neuronal stimulation enhances Plk2 kinase activity via a calcium/calcineurin pathway to counteract PP2A phosphatase activity for efficient phosphorylation of membrane-bound α-synuclein. Patch clamping of rat SNCA−/− neurons expressing exogenous wild-type or phospho-incompetent (S129A) α-synuclein suggests that pS129 fine-tunes the balance between excitatory and inhibitory neuronal currents. Consistently, our novel S129A knock-in (S129AKI) mice exhibit impaired hippocampal plasticity. The discovery of a key physiological function for pS129 has implications for understanding the role of α-synuclein in neurotransmission and adds nuance to the interpretation of pS129 as a synucleinopathy biomarker

Characterization of Brain Lysosomal Activities in GBA-Related and Sporadic Parkinson’s Disease and Dementia with Lewy Bodies

Mutations in the GBA gene, encoding the lysosomal hydrolase glucocerebrosidase (GCase), are the most common known genetic risk factor for Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). The present study aims to gain more insight into changes in lysosomal activity in different brain regions of sporadic PD and DLB patients, screened for GBA variants. Enzymatic activities of GCase, β-hexosaminidase, and cathepsin D were measured in the frontal cortex, putamen, and substantia nigra (SN) of a cohort of patients with advanced PD and DLB as well as age-matched non-demented controls (n = 15/group) using fluorometric assays. Decreased activity of GCase (− 21%) and of cathepsin D (− 15%) was found in the SN and frontal cortex of patients with PD and DLB compared to controls, respectively. Population stratification was applied based on GBA genotype, showing substantially lower GCase activity (~ − 40%) in GBA variant carriers in all regions. GCase activity was further significantly decreased in the SN of PD and DLB patients without GBA variants in comparison to controls without GBA variants. Our results show decreased GCase activity in brains of PD and DLB patients with and without GBA variants, most pronounced in the SN. The results of our study confirm findings from previous studies, suggesting a role for GCase in GBA-associated as well as sporadic PD and DLB

Robotically driven construction of buildings: Exploring on-demand building components production

Robotically Driven Construction of Buildings (RDCB) is an exploration into design to production solutions for robotically driven construction of buildings initiated by the faculties of Civil Engineering and Architecture, TU Delft and Architecture, TU Eindhoven and implemented 2014 within the 3TU Lighthouse framework. The aim of was to involve the disciplines of architecture, robotics, materials science, and structural design in order to integrate knowledge from the individual disciplines and develop new numerically controlled manufacturing techniques and building-design optimisation methods for adding creative value to buildings in a cost-effective and sustainable way.RDCB builds up on expertise developed at Hyperbody with respect to applications of robotics in architecture and this paper presents the contribution of the Robotic Building team from Hyperbody, Faculty of Architecture, TU Delft to the RDCB project. The contribution is in line with Europe’s aim to improve material and energy efficiency of buildings and efficiency of construction processes. Robotically driven construction and customised building materials have the potential to realise this in a cost-effective way and at the same time reduce accidents and health hazards for workers in the building sector. In order to achieve this RDCB is distributing materials as needed and where needed. This requires exploration of a variety of techniques and implies working with customised materials and techniques while finding the best methods of applying materials in the logic of specific force flows or thermal dissipation patterns.RDCB advances multi- and trans-disciplinary knowledge in robotically driven construction by designing and engineering new building systems for the on-demand production of customisable building components (Bier, 2014). The main consideration is that in architecture and building construction the factory of the future employs building materials and components that can be on site robotically processed and assembled