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Circuit Design of DS Spread Spectrum ReceiverKuo, Che-Yu 09 September 2009 (has links)
Traditionally in CDMA system, selective rake receiver is the popular method of
detection. When used in DS-UWB system, the complex in door environment will
increase the channel paths. As the channel paths increase, the more fingers which are
part of Rake receiver will increase. It will be difficult for hardware implement when
consider the operation of channel estimation and Rake receiver. And it is unfavorable
for hardware design.
In this thesis, we will use partial Rake receiver to replace selective Rake receiver.
Channel estimation is implemented by template the receiver signals within 2 bit time
window length. The performance is acceptable and the hardware complexity is
reduced. When implement the channel estimation, we combine some blocks of
acquisition and channel estimation for reducing hardware complexity.
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Fibre Channel im Einsatz in Storage Area Networks (SAN)Glöckner, Alexander 06 June 2001 (has links)
Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur "Rechnernetze und verteilte Systeme" der Fakultaet fuer Informatik der TU Chemnitz.
Workshop-Thema: Mobilitaet
Dieser Vortrag beschreibt neue Techniken zum Speichern grosser Datenmenge, auch über grosse Entfernungen hinweg.
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Winter habitat use of fishes in the Ohio RiverLenz, Benjamin Ernst, January 1900 (has links)
Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains ix, 85 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Urbanization and its effects on channel morphologyMcCann, Cody James 28 April 2014 (has links)
A focus on river and stream morphology with a specific emphasis on how urbanization and human impacts affect river channels. In the study of rivers, specifically looking at how the channel geometry changes with time, there are five main physical factors described that affect the channel morphology: (1) bank and bar stability; (2) sediment size distribution; (3) sediment supply; (4) flow variability; and (5) downstream slope, width and height. Understanding how these five factors affect channel form is vital in constructing realistic and accurate models of rivers and how they change over time. It is also important to understand some of the limitations of the combined modeling of all these factors together for a general stream.
Research studies are presented in order to further understand what knowledge has been acquired, and what areas are lacking in adequate understanding. Examples of cases where urbanization and land use change have a large impact and almost no impact are examined. It is important to understand what the limiting factors are in such cases, and whether it is possible to mitigate the effects or urbanization by any means other than natural channel phenomenon.
A two-dimensional hydrodynamic and sediment transport model is thoroughly described. The model is evaluated and verified, and potential problems and limitations are then discussed. Then a one-dimensional sediment transport and bed variation model is examined and tested using parameter controlled cases.
Urbanization increase near rivers and streams reduces the time frame over which certain natural events would have occurred in those channels. The affects of urbanization include but are not limited to changes in streamflow, sediment transport and deposition, channel bank stability, and increased channel widening. The magnitude of these affects will increase over time if careful steps are not taken to minimize the human influence within channels. / text
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Channel Partner - Atlas Copco : Increasing the engagement of the different players in the sales channelStrömsholm, Lovisa, Wu, Karin January 2015 (has links)
The Atlas Copco group is an industrial group of companies that are making sales with customers located all around the world. This thesis is done at the ACTA-GI division (Atlas Copco Tools and Assembly Systems GI Division), where the sales process stretches through four main players; the Atlas Copco headquarter in Stockholm, local customer centers, distributors and end customers. When having several different players in the sales process, the communication between these may sometimes be deficient. When news and information from the headquarter is released, it has to travel through several instances before reaching the distributors or the end customers. This leads to a deficient flow of communication where information is often delayed or misinterpreted before reaching its target. The purpose of this master thesis is to investigate how ACTA-GI can improve the flow of information in the sales channel and to develop a plan of action for increasing the engagement of the distribution partners by developing an online distributor portal. In order to investigate the best ways of handling distribution partners, this study contains both qualitative and quantitative research methods. The study contain a theory review on distribution and communication strategies, an analysis of the existing sales channels and current markets, an analysis of the content of the online portal, and a benchmarking study with a similar industrial company. The result is a plan of action for industry best practice and proposals for improvement areas.
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Channel Modeling Based on Bidirectional Analytic Ray Tracing and Radiative Transfer (RT²)Xu, Feng, Hue, Yik-Kiong, Ponnaluri, Satya P. 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The extremely large electrical-size and complexity of terrain scene poses great challenge in channel modeling of aeronautic telemetry. It becomes even more difficult if severe multipath and fading present due to scattering and attenuation of ground, terrain objects and precipitation [Rice, 2004]. This is critical in more sophisticated test scenarios involving low flying unmanned air vehicles and helicopters tested over water at high sea states, in hilly terrain, or even over urban environment. Conventional ray tracing and simple Fresnel reflection are not sufficient to characterize such complex channels. Hence, the novel bidirectional analytic ray tracing and radiative transfer (RT²) is proposed for advanced telemetry channel modeling.
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Limited feedback for multicell cooperative systemsBhagavatula, Ramya 11 February 2011 (has links)
Cellular systems are interference limited in nature. This problem is further accentuated in upcoming commercial wireless standards, which intend to use all the available spectrum in every cell in the network to improve peak data rates. This, however, could lead to considerable interference among neighboring cells, decreasing data rates and causing outages at the cell-edge. Multicell cooperation offers a solution for reducing the high levels of interference. The basic idea is that base stations coordinate transmissions by sharing user information among themselves via backhaul links. With the backhaul being bandwidth limited, cooperative strategies that involve the exchange of only user channel state information (CSI) among base stations offer the best tradeoff between complexity, backhaul load and performance gains. This dissertation focuses on these partial cooperative techniques, known as coordinated beamforming in 3GPP LTE Advanced.
In existing frequency division duplex systems, users estimate and feedback the CSI of a single channel over a finite-bandwidth feedback link, using limited feedback techniques. In a multicell cooperative scenario, each user needs to transmit the CSI of multiple channels using the same feedback link. This implies that the available feedback bandwidth must be efficiently shared among different channels to maximize performance gains in the cellular network.
This dissertation develops three different approaches to limited feedback in multicell cooperative systems. The first technique, separate quantization, involves each channel being fed back individually using a different codebook. Closed-form expressions are derived to partition adaptively the available feedback bits, as a function of the signal strengths and delays associated with each of the multiple channels. The second strategy is known as joint quantization, where the CSI of all the channels are quantized together as a composite vector. It is shown that though this approach yields higher data rates with smaller feedback requirements than separate quantization, it requires the design and storage of special codebooks. Finally, predictive joint quantization is proposed to exploit the temporal correlation of the wireless channel to reduce feedback requirements significantly as compared to the other two strategies, at the cost of high complexity at the user terminals. / text
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Transcriptional mechanisms that produce BK channel-dependent drug tolerance and dependenceLi, Xiaolei, Ph. D. 24 January 2012 (has links)
Tolerance to anesthetic drugs is mediated partially by homeostatic mechanisms that attempt to restore normal neural excitability. The BK-type Ca2+-activated K+ channel, encoded by the slo gene, plays an important role in this neural adaptation. In Drosophila, a single sedative dose of the organic solvent anesthetic benzyl alcohol induces dynamic spatiotemporal changes in histone H4 acetylation across the slo regulatory region and leads to slo induction and tolerance. Mutations ablating the expression of slo also block the acquisition of tolerance, whereas activating the expression of a slo transgene results in resistance to drug sedation. Moreover, artificially inducing histone acetylation with the histone deacetylase inhibitor causes similar acetylation changes, slo induction, and functional tolerance to the drug. Histone acetylation changes occur over two highly conserved non-coding DNA elements, 6b and 55b, of the slo control region. To investigate the function of these two elements, I generated individual knockout mutants by gene targeting. Both knockout alleles are backcrossed into the CS wild type background. The 6b element seems to repress slo induction after drug sedation, because the 6b knockout allele overreacts to the drug. Compared to the wild type, 6b knockout allele shows a much greater slo message induction after drug sedation, it also displays stronger enhancements in seizure susceptibility and following frequency. In addition, the 6b deletion causes a persistent tolerance for at least a month, while tolerance only lasts about 10 days in wild type flies. My investigation also indicates that the 55b element limits basal slo expression in muscle. Finally, to investigate if the particular histone acetylation spikes are required for drug-induced slo induction and tolerance, I tether the histone-modifying enzymes, HDAC or HAT, to the 6b and 55b DNA elements, respectively. I observe that the positioning of an HDAC on these two elements blocks drug-induced slo induction and the development of tolerance. Therefore, histone acetylation across slo control region is required for the activation of slo and the acquisition of tolerance. / text
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Auditors' evaluation of evidence: The effect of communication medium and management informationCarlisle, Melissa 21 September 2015 (has links)
This study investigates the effect of communication channel (e.g., face-to-face, written) and management information (i.e., background information on the reliability of client personnel) on auditors’ judgments of evidence persuasiveness in a management inquiry setting. Management information directs auditors to focus on the source of the evidence, creating a goal of assessing management during evidence collection. Auditors are distracted away from the evidence when the communication channel presents management characteristic cues (i.e., face-to-face), unrelated to the message and related to their new unconscious goal of assessing management. By comparison, when evidence is communicated by a channel that does not provide additional management characteristic cues (i.e. written), auditors are better able to evaluate the evidence without distraction. I predict an interaction effect, where communication channel effects auditor judgments when management information is provided, but not otherwise.
I design a 2x2 between-participants experiment to test my theory and present results of an experiment with 122 practicing senior auditors. Auditor participants receive an explanation from a client’s assistant controller to explain an unexpected fluctuation in a financial ratio. I manipulate the means by which the assistant controller communicates with the auditor (communication channel) and the presence of background information about the assistant controller (management information). Results of my experiment indicate an interaction effect of the communication channel and management information. When management information is provided, auditors assess the evidence as more persuasive when communication is face-to-face versus text. Auditors not receiving management information do not assess the evidence any differently, irrespective of communication channel. I also find evidence that auditors assess management differently when management information is provided. The results suggest that auditors are focused more on evaluating management when communicating through face-to-face versus written channels. Further, these assessments of management are consistent with the pattern of persuasiveness, indicating that they use this information more in their judgments when communicating face-to-face versus text and only when management information is provided. The results of this research suggest auditors may be assessing evidence as more persuasive than merited when management information is present and auditors are communicating with management face-to-face. Auditors as well as regulators should be aware of this effect so that adjustments can be made. Future researchers should consider these results in future research on management inquiry.
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Σχεδίαση και υλοποίηση ενός LDPC αποκωδικοποιητή για DVB-S2 συστήματαΚορδώνη, Μαρίνα 20 October 2009 (has links)
Tα σύγχρονα τηλεπικοινωνιακά συστήματα έχουν υιοθετήσει κώδικες διόρθωσης λαθών με στόχο να αυξήσουν της αξιοπιστία των συστημάτων κατά τη μετάδοση πληροφορίας. Οι LDPC (Low-Density-Parity-Check codes) κώδικες είναι μία κατηγορία κωδίκων που πρόσφατα άρχισαν να απασχολούν την επιστημονική κοινότητα κι αυτό γιατί διαθέτουν εξαιρετικές επιδόσεις. Οι κώδικες αυτοί είναι γραμμικοί block κώδικες με απόδοση πολύ κοντά στο όριο του Shannon. Επιπλέον, ο εύκολος παραλληλισμός της διαδικασίας αποκωδικοποίησής τους, τους καθιστά κατάλληλους για υλοποίηση σε υλικό.
Στην παρούσα διπλωματική μελετήθηκαν αρχικά τα ιδιαίτερα χαρακτηριστικά και οι παράμετροι των κωδίκων αυτών. Ο στόχος ήταν να σχεδιαστεί ένας αποκωδικοποιητής που να υποστηρίζει τα χαρακτηριστικά των LDPC κωδίκων που έχουν υιοθετηθεί από το DVB-S2. Με αυτό το στόχο υλοποιήθηκε στο System Generator(εργαλείο του Xilinx) ένας ημιπαράλληλος αποκωδικοποιητής. Η ημιπαράλληλη αρχιτεκτονική επιτρέπει καταλαμβάνοντας μικρή περιοχή του υλικού να δημιουργηθεί ένας αποκωδικοποιητής που να είναι εφικτό να χρησιμοποιείται από οποιοδήποτε κώδικα με χρήση των ίδιων λειτουργικών μονάδων και διαφορετικών μονάδων ελέγχου. Στην αποκωδικοποίηση χρησιμοποιήθηκε ο Min-Sum αλγόριθμος καθώς αυτός προσφέρει χαμηλή πολυπλοκότητα χωρίς να θυσιάζει αρκετά σε επίπεδο απόδοσης. Η σωστή λειτουργία ολόκληρου του σχεδιασμού επιβεβαιώθηκε με εξομοιώσεις στη Matlab. / Modern telecommunication systems have adopted error correction codes in order tor improve the reliability during information transmission. LDPC (Low-Density-Parity-Check codes) are a special group of codes with extremely good performance. These codes are linear block codes with performance near to the theoretical Shannon limit. Furthermore, the fact that the procedure of the decoding is easily parallelism makes them suitable for implementation on hardware.
At the beginning of this thesis, the special characteristics and the parameters of these codes were stated. The main aim was to design a decoder that can be used for the DVB-S2 system. So, it was designed at System Generator a semi parallel decoder. The implementation of this architecture allows every code (block size, code rate) to be decoded, using the same functional units and different control units. Moreover this implementation requires small area but it is not possible to succeed high throughput. For the decoding process, Min-Sum Algorithm has been used, as it is the less complex algorithm for hardware implementations.The design has been successfully verified with simulations using Matlab.
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