• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1166
  • 244
  • 142
  • 131
  • 118
  • 57
  • 46
  • 33
  • 28
  • 28
  • 28
  • 28
  • 28
  • 28
  • 24
  • Tagged with
  • 2402
  • 354
  • 293
  • 249
  • 228
  • 211
  • 202
  • 199
  • 191
  • 149
  • 130
  • 125
  • 109
  • 105
  • 105
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Design and performance evaluation of RAKE finger management schemes in the soft handover region

Choi, Seyeong 15 May 2009 (has links)
We propose and analyze new finger assignment/management techniques that are applicable for RAKE receivers when they operate in the soft handover region. Two main criteria are considered: minimum use of additional network resources and minimum call drops. For the schemes minimizing the use of network resources, basic principles are to use the network resources only if necessary while minimum call drop schemes rely on balancing or distributing the signal strength/paths among as many base stations as possible. The analyses of these schemes require us to consider joint microscopic/macroscopic diversity techniques which have seldom been considered before and as such, we tackle the statistics of several correlated generalized selection combining output signal-to-noise ratios in order to obtain closed-form expressions for the statistics of interest. To provide a general comprehensive framework for the assessment of the proposed schemes, we investigate not only the complexity in terms of the average number of required path estimations/comparisons, the average number of combined paths, and the soft handover overhead but also the error performance of the proposed schemes over independent and identically distributed fading channels. We also examine via computer simulations the effect of path unbalance/correlation as well as outdated/imperfect channel estimations. We show through numerical exam ples that the proposed schemes which are designed for the minimum use of network resources can save a certain amount of complexity load and soft handover overhead with a very slight performance loss compared to the conventional generalized selection combining-based diversity systems. For the minimum call drop schemes, by accurately quantifying the average error rate, we show that in comparison to the conventional schemes, the proposed distributed schemes offer the better error performance when there is a considerable chance of loosing the signals from one of the active base stations.
282

none

TENG, CHEN-MING 28 July 2003 (has links)
Thanks to Taiwan¡¦s geographic advantage of being located in subtropics, tropical fruits in Taiwan have high quality. There is never shortage of variously fresh and high-quality fruits in four seasons of a year in Taiwan, which should have gained Taiwan competitive advantages in international markets and should have made Taiwan nominated to be a standard for international markets. However, a large number of problems and difficulties in production and marketing system of the fruit industry have caused tropical fruits in Taiwan unable to get into foreign markets. The prospect of this research is to find out the influential marketing factors by carefully examining export and other related difficulties; consequently, the purpose of this research is to find out the most effective solutions among a large number of marketing factors to help the fruit industry in Taiwan out of difficulties. The research methods used in this study are interviewing fruit production and marketing professionals to analyze the fruit export difficulties, assisted with marketing 4P and STP structure, brand thesis, and real case studies. With the above mentioned methods, I structurally analyze difficulties and problems. According to the findings of this research, tropical fruits in Taiwan evidently have powerful competitive advantages; however, the ¡§Product¡¨ aspect of 4P is still the major factor that should be solved at first when tropical fruits in Taiwan confront export competition. All of the followings, fruit classification, production capacity management, packing, freezing, inspection, brand and the other related factors, are the main problems mentioned consistently by professionals. This research also finds that ¡§brand¡¨ makes industry, government, schools reach one accord; therefore, it should be taken as our long-term developmental direction and the best strategy to resuscitate Taiwan¡¦s fruits in international markets. Nevertheless, as it is shown on the related documents, Council of Agriculture¡¦s brand identification system is nothing more than just providing a name to a species of fruit, which is unable to build up its fame to domestic consumers and much less to foreign markets. According to the above findings of this research, four suggestions are proposed as follows: 1. Establishment of national brand series: to take advantage of Taiwan¡¦s great fame, using its name to sell our tropical fruits, and to take rural towns¡¦ or Co-operatives¡¦ brand as the sub-brand or the extensive brand. 2. Brand clock: to promote and cross sell fruits in different seasons based on different fruit periods. To construct brand life span with brand clock by taking national brand as the principal axis and assisted with season fruits¡¦ production periods; as a result, Taiwan¡¦s fruits can be sufficiently provided to export markets all the year around, keeping out from unstable supply that Taiwan has confronted for a long time. 3. Market Segmentation and Positioning: tropical fruits enjoy the advantage of freshness and numerous species, but they are difficult to keep fresh. Although freezing technology has been improved a lot, keeping tropical fruits fresh during a long distance transportation is always a real challenge. Consequently, choosing a proper market to do marketing according to the feature of every kind of fruit is highly recommended. This will avoid fruit quality from declining caused by blindly selling all fruits to uncompetitive markets or caused by a long distance transportation. Both of the above situations will cause a negative impact on brand. 4. Fruit identification: to take fruits that agricultural units can easily promote as the major products, to enhance production, to abandon uncompetitive species of fruits, to effectively manage and control fruit cultivating technology (Intelligent property right and species control), and to promote fruit identification system. All of the above methods will help Taiwan¡¦s fruit industry have their competition in the market.
283

Contribution of potassium channels to myogenic response in skeletal muscle arterioles: effects of age and fiber type

Kim, Se Jeong 30 October 2006 (has links)
In isolated skeletal muscle arterioles, increasing transmural pressure causes an increase in constriction. This active myogenic response varies with age and fiber type. Increased transmural pressure activates both Ca2+-activated (KCa) potassium channels and voltage-dependent (Kv) potassium channels; these channels have a role in the negativefeedback pathways that modulate depolarization and myogenic constriction. We tested the hypothesis that increased KCa channel and Kv channel activity contribute to reduced myogenic responsiveness in skeletal muscle arterioles of aged rats. 1A arterioles were isolated from soleus, an oxidative muscle, and superficial gastrocnemius, a glycolytic muscle, of young (4 mos) and aged (24 mos) Fischer 344 rats. Myogenic responses were assessed by increasing intraluminal pressure (0-140 cm H2O) in increments of 20cm H2O. Vasoconstrictor response were determined in response to increasing concentrations of the KCa channel blocker, charybdotoxin (CTX; 10-10 to 10-7 M) and the Kv channel blocker, 4-Aminopyridine (4-AP; 10-5 to 10-2 M). To determine the role of potassium channels in modulating the myogenic response, cannulated arterioles from soleus and gastrocnemius were incubated with CTX (50 nM) and 4-AP (5mM) for 15 minutes prior to evaluation of the myogenic response. Increased Kv channel activity contributes to reduced myogenic constriction in soleus and gastrocnemius muscle arterioles from aged rats. In soleus muscle arterioles, KCa channel activity opposes myogenic tone in young but not old rats. In gastrocnemius muscle arterioles, treatment with CTX did not eliminate age-related differences in the myogenic response, and the KCa channel contribution to myogenic tone was, in fact, greater arterioles from young as compared to old rats. Kv channels contribute to greater myogenic constriction in soleus arterioles, KCa channels appear to be more active in gastrocnemius muscle arterioles as compared to soleus muscle arterioles. Therefore Kv and KCa channels are tonically active in skeletal muscle arterioles, contributing to a hyperpolarizing force that opposes myogenic constriction. Furthermore, increased Kv channel activity contributes to the age-related reduction of myogenic constriction in soleus and gastrocnemius muscle arterioles.
284

Pose Recognition for Tracker Initialization Using 3D Models

Berg, Martin January 2008 (has links)
<p>In this thesis it is examined whether the pose of an object can be determined by a system trained with a synthetic 3D model of said object. A number of variations of methods using P-channel representation are examined. Reference images are rendered from the 3D model, features, such as gradient orientation and color information are extracted and encoded into P-channels. The P-channel representation is then used to estimate an overlapping channel representation, using B<sub>1</sub>-spline functions, to estimate a density function for the feature set. Experiments were conducted with this representation as well as the raw P-channel representation in conjunction with a number of distance measures and estimation methods.</p><p>It is shown that, with correct preprocessing and choice of parameters, the pose can be detected with some accuracy and, if not in real-time, fast enough to be useful in a tracker initialization scenario. It is also concluded that the success rate of the estimation depends heavily on the nature of the object.</p>
285

MIMO beamforming in multiuser wireless environments

Kang, Deokwon. January 2009 (has links)
Thesis (M.S.E.C.E.)--University of Delaware, 2009. / Principal faculty advisor: Leonard J. Cimini, Jr., Dept. of Electrical & Computer Engineering. Includes bibliographical references.
286

Transcriptional control of slowpoke, a calcium activated potassium channel gene /

Bohm, Rudy Ashish, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 120-134). Available also in a digital version from Dissertation Abstracts.
287

Relationships between stream geomorphology and fish community structure and diversity in Maine /

Gaenzle, Emily, January 2002 (has links)
Thesis (M.S.) in Ecology and Environmental Sciences--University of Maine, 2002. / Includes vita. Bibliography: leaves 57-59.
288

Regulation of electrical excitability individual, gender and hormonally-induced variation in potassium channel expression in the electric organ /

Few, William Preston. January 2003 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.
289

Dispersion prediction in open channel flows /

Lui, Ping-hon. January 1982 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1982.
290

ATP-sensitive potassium channels (Katp) in fish cardiac muscle during anoxia and recovery /

MacCormack, Tyson, January 2001 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2002. / Includes bibliographical references.

Page generated in 0.0474 seconds