188 research outputs found

    Evaluation Lkw-Parkleitsystem BAB A45

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    Zwischen der Nachfrage nach Parkmöglichkeiten für Lkw an Autobahnen und dem Angebot besteht trotz der umfangreichen Erhöhung der Parkkapazitäten in den letzten Jahren ein erhebliches Defizit. Das Bundesverkehrsministerium will dieses Defizit neben dem Aus- und Neubau von Rastanlagen unter anderem durch den Einsatz von Parkleitsystemen reduzieren. Das vorliegende Forschungsprojekt widmet sich der Evaluation solcher Parkleitsysteme. Im Vorlauf zum Forschungsprojekt wurde ein Lkw-Parkleitsystem (PLS) für Rastanlagen an Bundesautobahnen entwickelt und in einem Testgebiet mit 4 Rastanlagen auf der BAB A45 aufgebaut. Primäres Ziel des PLS ist die Ermittlung und Kommunikation der freien Lkw-Parkstände auf Rastanlagen. Dazu wurden ein „Parkplatzdetektionssystem mit flächenhafter Erfassung“ und dynamische Anzeigetafeln eingesetzt. Zur Prüfung der Wirksamkeit des PLS wurden die Lkw-Routen im Testgebiet nach der Kennzeichenerfassungsmethode ermittelt. Die Messungen und Auswertungen umfassten zeitlich 7 Phasen, in denen unterschiedliche Informationsumfänge den auf der BAB A45 Richtung Gießen verkehrenden Lkw angeboten wurden. Zusätzlich wurde das PLS über eine Befragung der Lkw-Fahrerinnen und Fahrer bewertet. Die Auswertungen ergaben folgendes Bild: 1. Lkw-Fahrer, deren Lenkzeit zugunsten einer Ruhephase unterbrochen werden muss, sind an den Informationen des PLS über freie Parkstände in hohem Maße interessiert. Für die Entscheidung zugunsten eines Parkstandes zum Abhalten der Ruhephase sind die Informationen über freie Parkstände auf Grundlage der durchgeführten Befragung eine wichtige Hilfe. Durch die Messungen konnte diese Aussage allerdings nicht verifiziert werden. 2. Bei der Untersuchung des Parkplatzwahlverhaltens konnte trotz des geäußerten Interesses keine signifikante Veränderung beim Vergleich der Messphasen mit unterschiedlichem Informationsumfang des PLS nachgewiesen werden: Hohe Auslastungen in der PWC Pfingstweide und der PWC Stauferburg wurden nicht in nennenswertem Umfang abgebaut, freie Parkstände auf der T+R Langen-Bergheim wurden nicht genutzt. Auch ein Einfluss des PLS auf den Parksuchverkehr konnte nicht festgestellt werden. 3. Das Parkverhalten innerhalb der Rastanlagen wurde ebenfalls räumlich und zeitlich differenziert untersucht. Positiv zeigte sich hier die sortiertere Befüllung nach Einführung des PLS: Zuerst werden die StVO-Parkstände gefüllt, es folgt das geduldete Parken in Fahrgassen z.B. hinter den gefüllten Schrägparkständen und erst im Anschluss daran bei hohem Parkdruck auch behinderndes und gefährdendes Parken. Die zusätzliche Bereitstellung von Parkinformationen innerhalb der Rastanlagen hat diesen gewünschten Effekt weiter unterstützt. 4. Während der Messphasen entspannte sich der ursprünglich vorhandene Parkdruck aufgrund des Rückgangs des Lkw-Verkehrs. Neben der allgemeinen Verkehrsentwicklung spielte auch die Brückenproblematik auf der BAB A45 für den Rückgang eine Rolle. Daraus folgend war für Lkw-Fahrerinnen und Fahrer die Entscheidung zugunsten einer Rastanlage mit freien Parkständen weniger relevant. Im Rahmen der Untersuchungen wurden die folgenden offenen Fragestellungen zum Lkw-Parken erkannt • Analyse der Kapazität von Längsparkstreifen als dynamische Größe • Untersuchung des Zusammenspiels der unterschiedlichen Einflussfaktoren auf das Parkverhalten von Lkw-Fahrerinnen und Fahrern auf Rastanlagen • Weitere Analyse von kurzen Verweilzeiten auf Rastanlagen die nicht Teil des vorliegenden Forschungsvorhabens waren.Despite the continuous construction and enlargement of rest areas along the motorways in Germany, there has been a significant gap between the demand for truck parking and the supply. The German Federal Ministry of Transport wants to reduce this deficit not only by expanding and building new rest areas, but also with other measures such as the use of parking guidance systems. This research project is dedicated to the evaluation of parking guidance systems. In the run-up to the research project, a truck parking guidance system (PLS) for rest areas on federal motorways was developed and set up in a test area with 4 rest areas on the A45 motorway. The primary goal of the PLS is to determine and communicate free truck parking spaces at rest areas. For this purpose, a "parking detection system with area coverage" was used. To test the effectiveness of the PLS, the truck routes in the test area were determined using the number plate recognition method. The measurements and evaluations comprised 7 phases in which different amounts of information were offered to the trucks traveling on the A45 motorway in the direction of Giessen. In addition, the PLS was evaluated via a survey of truck drivers. The evaluations produced the following picture: 1. Truck drivers whose driving time has to be interrupted in order to take a break are very interested in the information from the PLS about free parking spaces. The information on free parking spaces based on the survey carried out is an important aid for the decision in favor of a parking space for the rest period. However, this statement could not be verified by the measurements. 2. When examining the parking choice behavior, despite the interest expressed, no significant change could be detected when comparing the measurement phases with different amounts of information from the PLS: High occupancy rates in the rest areas PWC Pfingstweide and the PWC Stauferburg were not reduced to any significant extent, free parking spaces on the T+ R Langen-Bergheim were not used. An influence of the PLS on the parking search traffic could not be determined either. 3. The parking behavior within the rest areas was also examined in a spatially and temporally differentiated manner. The more sorted filling after the introduction of the PLS was positive here: First the legal parking spaces are filled, followed by tolerated parking in driving lanes, e.g. behind the filled inclined parking spaces, and only then with high parking pressure also obstructive and dangerous parking. The additional provision of parking information within the rest areas has further supported this desired effect. 4. During the measurement phases, the originally existing parking pressure relaxed due to the decrease in truck traffic. In addition to the general traffic development, the bridge problem on the BAB A45 also played a role in the decline. As a result, the decision in favor of a rest area with free parking spaces was less relevant for truck drivers. The following open questions about truck parking were identified as part of the investigations • Analysis of the capacity of parking lanes as a dynamic variable • Investigation of the interaction of the different influencing factors on the parking behavior of truck drivers at rest areas • Further analysis of short dwell times at rest areas which were not part of the present research project

    Preliminary archaeoentomological analyses of permafrost-preserved cultural layers from the pre-contact Yup’ik Eskimo site of Nunalleq, Alaska : implications, potential and methodological considerations

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    Acknowledgements Site excavation and samples collection were conducted by archaeologists from the University of Aberdeen, with the help of archaeologists and student excavators from the University of Aberdeen University of Alaska Fairbanks and Bryn Mawr College, Kuskokwim Campus, College of Rural Alaska and residents of Quinhagak and Mekoryuk. This study is funded through AHRC grant to the project ‘Understanding Cultural Resilience and Climate Change on the Bering Sea through Yup’ik Ecological Knowledge, Lifeways, Learning and Archaeology’ to Rick Knecht, Kate Britton and Charlotta Hillderal (University of Aberdeen; AH/K006029/1). Thanks are due to Qanirtuuq Inc. and Quinhagak, Alaska for sampling permissions and to entomologists working at the CNC in Ottawa for allowing access to reference collections of beetles, lice and fleas. Yves Bousquet, Ales Smetana and Anthony E. Davies are specially acknowledged for their help with the identification of coleopteran specimens. Finally, we would also like to thank Scott Elias for useful comments on the original manuscript.Peer reviewedPublisher PD

    Noncytopathic Clearance of Lymphocytic Choriomeningitis Virus from the Hepatocyte

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    We have previously shown that interferon and tumor necrosis factor noncytopathically abolish hepatitis B virus (HBV) replication from the hepatocyte and kidney tubular epithelial cells in vivo. Here we show that a persistent lymphocytic choriomeningitis virus (LCMV) infection is cleared from the hepatocyte noncytopathically when the same cytokines are induced in the liver by antigen-nonspecific stimuli. These results indicate that, like HBV, LCMV is also susceptible to intracellular inactivation by cytokine-induced antiviral mechanisms that are operative in the hepatocyte. In contrast, LCMV is not cleared from intrahepatic nonparenchymal cells or splenocytes, indicating that, unlike the hepatocyte, these cells do not produce the factors required to inactivate LCMV. Antiviral mechanisms like these may have evolved to maintain the functional integrity of vital organs in the face of massive infection

    In-Datacenter Performance Analysis of a Tensor Processing Unit

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    Many architects believe that major improvements in cost-energy-performance must now come from domain-specific hardware. This paper evaluates a custom ASIC---called a Tensor Processing Unit (TPU)---deployed in datacenters since 2015 that accelerates the inference phase of neural networks (NN). The heart of the TPU is a 65,536 8-bit MAC matrix multiply unit that offers a peak throughput of 92 TeraOps/second (TOPS) and a large (28 MiB) software-managed on-chip memory. The TPU's deterministic execution model is a better match to the 99th-percentile response-time requirement of our NN applications than are the time-varying optimizations of CPUs and GPUs (caches, out-of-order execution, multithreading, multiprocessing, prefetching, ...) that help average throughput more than guaranteed latency. The lack of such features helps explain why, despite having myriad MACs and a big memory, the TPU is relatively small and low power. We compare the TPU to a server-class Intel Haswell CPU and an Nvidia K80 GPU, which are contemporaries deployed in the same datacenters. Our workload, written in the high-level TensorFlow framework, uses production NN applications (MLPs, CNNs, and LSTMs) that represent 95% of our datacenters' NN inference demand. Despite low utilization for some applications, the TPU is on average about 15X - 30X faster than its contemporary GPU or CPU, with TOPS/Watt about 30X - 80X higher. Moreover, using the GPU's GDDR5 memory in the TPU would triple achieved TOPS and raise TOPS/Watt to nearly 70X the GPU and 200X the CPU.Comment: 17 pages, 11 figures, 8 tables. To appear at the 44th International Symposium on Computer Architecture (ISCA), Toronto, Canada, June 24-28, 201

    Effects of Subthalamic Nucleus Lesions and Stimulation upon Corticostriatal Afferents in the 6-Hydroxydopamine-Lesioned Rat

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    Abnormalities of striatal glutamate neurotransmission may play a role in the pathophysiology of Parkinson's disease and may respond to neurosurgical interventions, specifically stimulation or lesioning of the subthalamic nucleus (STN). The major glutamatergic afferent pathways to the striatum are from the cortex and thalamus, and are thus likely to be sources of striatal neuronally-released glutamate. Corticostriatal terminals can be distinguished within the striatum at the electron microscopic level as their synaptic vesicles contain the vesicular glutamate transporter, VGLUT1. The majority of terminals which are immunolabeled for glutamate but are not VGLUT1 positive are likely to be thalamostriatal afferents. We compared the effects of short term, high frequency, STN stimulation and lesioning in 6-hydroxydopamine (6OHDA)-lesioned rats upon striatal terminals immunolabeled for both presynaptic glutamate and VGLUT1. 6OHDA lesions resulted in a small but significant increase in the proportions of VGLUT1-labeled terminals making synapses on dendritic shafts rather than spines. STN stimulation for one hour, but not STN lesions, increased the proportion of synapses upon spines. The density of presynaptic glutamate immuno-gold labeling was unchanged in both VGLUT1-labeled and -unlabeled terminals in 6OHDA-lesioned rats compared to controls. Rats with 6OHDA lesions+STN stimulation showed a decrease in nerve terminal glutamate immuno-gold labeling in both VGLUT1-labeled and -unlabeled terminals. STN lesions resulted in a significant decrease in the density of presynaptic immuno-gold-labeled glutamate only in VGLUT1-labeled terminals. STN interventions may achieve at least part of their therapeutic effect in PD by normalizing the location of corticostriatal glutamatergic terminals and by altering striatal glutamatergic neurotransmission

    What Happened to Gray Whales during the Pleistocene? The Ecological Impact of Sea-Level Change on Benthic Feeding Areas in the North Pacific Ocean

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    Gray whales (Eschrichtius robustus) undertake long migrations, from Baja California to Alaska, to feed on seasonally productive benthos of the Bering and Chukchi seas. The invertebrates that form their primary prey are restricted to shallow water environments, but global sea-level changes during the Pleistocene eliminated or reduced this critical habitat multiple times. Because the fossil record of gray whales is coincident with the onset of Northern Hemisphere glaciation, gray whales survived these massive changes to their feeding habitat, but it is unclear how.We reconstructed gray whale carrying capacity fluctuations during the past 120,000 years by quantifying gray whale feeding habitat availability using bathymetric data for the North Pacific Ocean, constrained by their maximum diving depth. We calculated carrying capacity based on modern estimates of metabolic demand, prey availability, and feeding duration; we also constrained our estimates to reflect current population size and account for glaciated and non-glaciated areas in the North Pacific. Our results show that key feeding areas eliminated by sea-level lowstands were not replaced by commensurate areas. Our reconstructions show that such reductions affected carrying capacity, and harmonic means of these fluctuations do not differ dramatically from genetic estimates of carrying capacity.Assuming current carrying capacity estimates, Pleistocene glacial maxima may have created multiple, weak genetic bottlenecks, although the current temporal resolution of genetic datasets does not test for such signals. Our results do not, however, falsify molecular estimates of pre-whaling population size because those abundances would have been sufficient to survive the loss of major benthic feeding areas (i.e., the majority of the Bering Shelf) during glacial maxima. We propose that gray whales survived the disappearance of their primary feeding ground by employing generalist filter-feeding modes, similar to the resident gray whales found between northern Washington State and Vancouver Island
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