59 research outputs found
SatellitengestĂŒtzte DatenĂŒbertragung
Diese Diplomarbeit beschreibt die Möglichkeiten des satellitengestĂŒtzten Datentransfers und richtet sich in erster Linie an Marketing- und Trademanager gröĂerer Handelsketten und Konzerne, sowie Multimedia-Agenturen, die auf der Suche nach technischen Neuerungen bei der Nutzung interaktiver Verkaufsterminals sind. Das Ziel ist, ĂŒber die Möglichkeiten und Vorteile der SatellitenĂŒbertragung umfassend zu informieren, Vorteile und Einsatzmöglichkeiten aufzuzeigen, den wirtschaftlichen Nutzen zu erlĂ€utern, sowie eventuell entstehende Probleme anzusprechen und Lösungsmöglichkeiten anzubieten. DarĂŒber hinaus werden die wichtigsten technischen Grundbegriffe geklĂ€rt, sowie aktuelle Standards angesprochen. Die Diplomarbeit enthĂ€lt des weiteren die an einem Fallbeispiel genau erlĂ€uterte Phasen der Entstehung und Implementierung eines satellitengestĂŒtzten POS-Netzes, sowie eine detaillierte Kostenauflistung
Observational Requirements for Lyman-alpha Forest Tomographic Mapping of Large-Scale Structure at z ~ 2
The z > 2 Lyman-alpha (Lya) forest traces the underlying dark-matter
distribution on large scales and, given sufficient sightlines, can be used to
create 3D maps of large-scale structure. We examine the observational
requirements to construct such maps and estimate the signal-to-noise as a
function of exposure time and sightline density. Sightline densities at z =
2.25 are n_los = [360, 1200,3300] deg^{-2} at limiting magnitudes of g =[24.0,
24.5,25.0], resulting in transverse sightline separations of d_perp = [3.6,
1.9, 1.2] h^{-1} Mpc, which roughly sets the reconstruction scale. We simulate
these reconstructions using mock spectra with realistic noise properties, and
find that spectra with S/N = 4 per angstrom can be used to generate maps that
clearly trace the underlying dark-matter at overdensities of rho/ ~ 1. For
the VLT/VIMOS spectrograph, exposure times t_exp = [4, 6, 10] hrs are
sufficient for maps with spatial resolution epsilon_3d = [5.0, 3.2, 2.3] h^{-1}
Mpc. Assuming ~ 250 h^{-1} Mpc is probed along the line-of-sight, 1 deg^2 of
survey area would cover a comoving volume of ~ 10^6 h^{-3} Mpc^3 at =2.3,
enabling efficient mapping of large volumes with 8-10m telescopes. These maps
could be used to study galaxy environments, detect proto-clusters, and study
the topology of large-scale structure at high-z.Comment: 18 pages, 10 figures. Accepted by Ap
Proceedings of the 5th bwHPC Symposium
In modern science, the demand for more powerful and integrated research
infrastructures is growing constantly to address computational challenges
in data analysis, modeling and simulation. The bwHPC initiative, founded
by the Ministry of Science, Research and the Arts and the universities in
Baden-WĂŒrttemberg, is a state-wide federated approach aimed at assisting
scientists with mastering these challenges. At the 5th bwHPC Symposium
in September 2018, scientific users, technical operators and government
representatives came together for two days at the University of Freiburg. The
symposium provided an opportunity to present scientific results that were
obtained with the help of bwHPC resources. Additionally, the symposium served
as a platform for discussing and exchanging ideas concerning the use of these
large scientific infrastructures as well as its further development
5. und 6. Tagung GMLÂČ 2007 und GMLÂČ 2008 ; 19. - 21. MĂ€rz 2007 / 13. - 14. MĂ€rz 2008 an der Technischen UniversitĂ€t Berlin und an der Freien UniversitĂ€t Berlin
Dem Lernen und Lehren mit Neuen Medien werden in Zeiten der
Informationsgesellschaft oft sagenhafte Eigenschaften zugeschrieben: es sei
anschaulicher, attraktiver, motivierender, effizienter, kostengĂŒnstiger, gehe
besser auf den Lernenden ein, steigere den Lernerfolg, orientiere sich mehr an
den kognitiven Strukturen von Lernenden etc.. Damit wenigstens einige der
genannten Vorteile wirksam werden, sind geeignete didaktische und methodische
Modelle und Konzepte unverzichtbar. Hinzu kommen detaillierte Kenntnisse in
der Gestaltung von LernoberflÀchen, der technischen Realisierung von
Lerninhalten, dem Aufbau lernförderlicher Strukturen und Betreuungskonzepte
und dem Betrieb von teilweise virtuellen UniversitÀten. Inwieweit gesteckte
Ziele erreicht wurden, ist anhand von EvaluationsmaĂnahmen zu ermitteln.
SĂ€mtliche Aspekte mĂŒssen bereits in die Planung entsprechender Angebote
einbezogen werden. Die Tagungsreihe widmet sich ausgewÀhlten Fragestellungen
dieses Themenkomplexes, die durch VortrÀge ausgewiesener Experten, durch
eingereichte BeitrÀge und durch Diskussionen in Arbeitsgruppen/Tutorials
intensiv behandelt werden. Der Schwerpunkt liegt dabei auf den didaktischen
und methodischen Konzepten, die im Rahmen multimedialer Lehre zum Einsatz
kommen. Zur PrÀsentation von Beispielszenarien, Projektergebnissen, Best-
Practice sowie zum Erfahrungsaustausch sind ebenfalls stets ausreichend
FreirÀume eingeplant. Als Zielgruppe sehen wir u.a. Interessentinnen und
Interessenten, die â vor allem im Raum Berlin/Brandenburg â an Entwicklung und
Einsatz von multimedialen Lehrangeboten arbeiten. Besonders angesprochen sind
Mitarbeiter und Mitarbeiterinnen in den laufenden BMBF-Förderprojekten im
Programm âNeue Medien in der Bildungâ und in Bildungsinitiativen und
-projekten zur Gestaltung der Informationsgesellschaft. Eingeladene
HauptvortrĂ€ge und eingereichte BeitrĂ€ge haben die GMLÂČ 2007 und die GMLÂČ 2008
neben einem Tutorial zu Serious Learning und der Verabschiedung von Thesen zu
den Grundfragen multimedialer Lehre und Lernens besonders geprÀgt. Es wurden
VortrÀge zur PrÀsentation angenommen aus Themenbereichen wie Lernszenarien,
Online-Learning, Methodik und Didaktik von Lernmodulen, Verteilte
Kollaboration, Folie und Blended Learning, hybride Lernumgebungen, Mobile
GerĂ€te fĂŒr Blended Learning, Instruktionsdesign, didaktische
Modellierungswerkzeuge, Lernplattformen, Knowledge Sharing, Medien in der
Softwareausbildung, E-Learning global, MedienverbĂŒnde, E-Learning
Produktionsprozess, Online-Betreuung, Kommunikation und Neue Medien im
Mathematikunterricht. Ein Posterprogramm begleitete die Tagungen. Die
Reihenfolge dieses Doppelbandes ist inhaltlich geordnet, in Reihenfolge
Konzepten des eLearning ĂŒber Studien/Projekte zu Werkzeugen
Library buildings around the world
"Library Buildings around the World" is a survey based on researches of several years. The objective was to gather library buildings on an international level starting with 1990
A study of the marine boundary layer by LES-modelling and experimental observations with a focus on offshore wind energy applications
[no abstract
Integration und Konnexion : Tagungsband zur 26. AKWI-Jahrestagung vom 15. bis 18.09.2013 an der Technischen Hochschule Mittelhessen
Das aufgerufene Thema âHerausforderungen an die Wirtschaftsinformatik: Integration und Konnexionâ provozierte BeitrĂ€ge, die thematisch ein sehr breites Spektrum abdecken. Neben theoretischen Betrachtungen und Definitionen des sicher noch nicht final geprĂ€gten Begriffs der Konnexion gab es auch sehr praktische BeitrĂ€ge wie die Darstellung von konkreten prototypischen Entwicklungsvorhaben. Auch das ist ein Indiz fĂŒr die lebendige Landschaft der Wirtschaftsinformatik an den deutschsprachigen Hochschulen fĂŒr Angewandte Wissenschaften
Model-Based Design, Analysis, and Implementations for Power and Energy-Efficient Computing Systems
Modern computing systems are becoming increasingly complex. On one end of
the spectrum, personal computers now commonly support multiple processing
cores, and, on the other end, Internet services routinely employ thousands of
servers in distributed locations to provide the desired service to its users. In
such complex systems, concerns about energy usage and power consumption
are increasingly important. Moreover, growing awareness of environmental
issues has added to the overall complexity by introducing new variables to the
problem. In this regard, the ability to abstractly focus on the relevant details
allows model-based design to help significantly in the analysis and solution of
such problems.
In this dissertation, we explore and analyze model-based design for energy
and power considerations in computing systems. Although the presented techniques
are more generally applicable, we focus their application on large-scale
Internet services operating in U.S. electricity markets. Internet services are becoming
increasingly popular in the ICT ecosystem of today. The physical infrastructure
to support such services is commonly based on a group of cooperative
data centers (DCs) operating in tandem. These DCs are geographically
distributed to provide security and timing guarantees for their customers. To
provide services to millions of customers, DCs employ hundreds of thousands
of servers. These servers consume a large amount of energy that is traditionally
produced by burning coal and employing other environmentally hazardous
methods, such as nuclear and gas power generation plants. This large energy
consumption results in significant and fast-growing financial and environmental
costs. Consequently, for protection of local and global environments, governing
bodies around the globe have begun to introduce legislation to encourage
energy consumers, especially corporate entities, to increase the share of
renewable energy (green energy) in their total energy consumption. However,
in U.S. electricity markets, green energy is usually more expensive than energy
generated from traditional sources like coal or petroleum.
We model the overall problem in three sub-areas and explore different approaches
aimed at reducing the environmental foot print and operating costs
of multi-site Internet services, while honoring the Quality of Service (QoS) constraints
as contracted in service level agreements (SLAs).
Firstly, we model the load distribution among member DCs of a multi-site Internet
service. The use of green energy is optimized considering different factors
such as (a) geographically and temporally variable electricity prices, (b)
the multitude of available energy sources to choose from at each DC, (c) the necessity
to support more than one SLA, and, (d) the requirements to offer more
than one service at each DC. Various approaches are presented for solving this
problem and extensive simulations using Googleâs setup in North America are
used to evaluate the presented approaches.
Secondly, we explore the area of shaving the peaks in the energy demand of
large electricity consumers, such as DCs by using a battery-based energy storage
system. Electrical demand of DCs is typically peaky based on the usage
cycle of their customers. Resultant peaks in the electrical demand require development
and maintenance of a costlier energy delivery mechanism, and are
often met using expensive gas or diesel generators which often have a higher
environmental impact. To shave the peak power demand, a battery can be used
which is charged during low load and is discharged during the peak loads.
Since the batteries are costly, we present a scheme to estimate the size of battery
required for any variable electrical load. The electrical load is modeled using
the concept of arrival curves from Network Calculus. Our analysis mechanism
can help determine the appropriate battery size for a given load arrival curve
to reduce the peak.
Thirdly, we present techniques to employ intra-DC scheduling to regulate the
peak power usage of each DC. The model we develop is equally applicable to
an individual server with multi-/many-core chips as well as a complete DC
with an intermix of homogeneous and heterogeneous servers. We evaluate
these approaches on single-core and multi-core chip processors and present the
results.
Overall, our work demonstrates the value of model-based design for intelligent
load distribution across DCs, storage integration, and per DC optimizations
for efficient energy management to reduce operating costs and environmental
footprint for multi-site Internet services
Structural studies of eukaryotic ribosome biogenesis and the sec and Bcs1 protein translocation systems
Three publications of this cumulative dissertation use cryo-electron microscopy (cryo-EM) to dissect the assembly pathway of the eukaryotic large ribosomal subunit (LSU). This pathway commences with freshly transcribed and initially unfolded rRNA in the nucleolus, which folds and incorporates ribosomal proteins while traveling to the cytoplasm, ultimately culminating in the mature LSU. During this highly complex pathway, the yeast cell must assemble four rRNAs and 79 ribosomal proteins with the help of over 200 assembly factors (AFs). Using cryo-EM, structures of nucleo\-plasmic and cytoplasmic assembly intermediates of the LSU could be solved in recent years, thus shedding light on the later stages of LSU formation. Early assembly steps remain enigmatic, as nucleolar LSU assembly intermediates have been biochemically but not structurally characterized.
Taken together, we solved the structure of seven nucleolar or early nucleoplasmic intermediates at resolutions ranging from 3.3 to 4.5 Ă
, showing a linear assembly sequence. The first five structures show how the rRNA of the LSU is incorporated stepwise, in a non-transcriptional sequence, first forming the solvent exposed back side, and later the peptide exit tunnel and parts of the intersubunit surface (ISS). At the late nucleolar stage, the L1-stalk rRNA of domain V blocks the site of central protuberance (CP) assembly and is stabilized in a premature conformation by a range of AFs associated with the meandering, long N-terminal tail of Erb1.
Two further structures show progression from this stage after release of the Erb1-Ytm1 complex by the Rea1 remodeling machinery. These intermediates, purified via Nop53, show dissociation of many early AFs from the premature ISS and destabilization of the L1-stalk. After subsequent release of the Spb1 methyltransferase, the L1-stalk rRNA can be accommodated in its mature conformation. This allows the premature CP to form, leading to a previously characterized nucleoplasmic intermediate, with a formed but premature CP. This particle is the substrate for the second Rea1 mediated structural remodeling, an intermediate of which we resolved to molecular resolution revealing Ipi1 as a central integrator for the Rix1-Ipi1-Ipi3 complex on this pre-60S particle.
The binding of the Rix1-Rea1 remodeling machinery at this nucleoplasmic stage progresses maturation by inducing a 180 rotation of the 5S ribonucleoprotein particle (5S RNP) and CP. Using a combination of yeast genetics and cryo-EM we investigated the function of the AF Cgr1 in this maturation step. We showed that Cgr1 is required for CP rotation to take place, likely by stabilizing the rotated conformation. The Cgr1 function can be bypassed by introducing suppressor mutations in Rpf2 and Rrs1, two factors stabilizing the CP prior to rotation.
Apart from ribosome biogenesis, two additional publications of this dissertation address protein translocation machinery, required for transport of proteins across or into membranes. The Sec translocon allows co- and posttranslational translocation of mostly unfolded substrates across the bacterial plasma and the eukaryotic endoplasmic reticulum (ER) membrane. We solved the structure of a stalled 70S ribosome-nascent chain complex (RNC) bound to the SecYEG translocon in a native like environment provided by a large lipid nanodisc. The structure shows all three subunits of the bacterial SecYEG complex and displays the lateral gate at a defined, early stage of opening or unzipping on the cytoplasmic side upon insertion of the signal anchor domain of the nascent chain.
Specific pathways, such as the assembly of the mitochondrial bc1 respiratory chain complex, require folding of proteins in one compartment before translocation across a membrane to allow the protein to be active in another compartment. The bc1-complex component Rip1 folds in the mitochondrial matrix and assembles a 2Fe-2S cluster before being translocated across the inner mitochondrial membrane (IM) by the AAA-protein Bcs1. We solved the structure of Bcs1 in an ADP-bound state and two apo states, displaying a heptameric ring of Bcs1 protomers. Bcs1 forms two large aqueous vestibules separated by a seal forming middle domain. One vestibule is accessible from the matrix side and one lies within the inner mitochondrial membrane. The architecture and structural dynamics between the three states suggest an airlock like mechanism, allowing transport of folded Rip1 while maintaining the permeability barrier of the membrane
- âŠ