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High linearity Transconductance-C Continuous-Time Filter for Multi-Mode CMOS Wireless ReceiversChen, Shan-you 08 August 2011 (has links)
Recently, with advances in CMOS process, the RF receiver which is integrated into the SOC chip can effectively reduce production costs. When designing the wireless receiver, one of the most important technologies is to design channel-selection filter. Typically, the design of the channel-selection filter in multi-standard high-frequency will take up a large chip area and higher power consumption. Therefore, in order to reduce the area and power consumption, this thesis designed a low-power OTA and low-pass filter.
This thesis presents a multi-mode wireless communication application in the receiver channel selection filter. This filter is designed to use the fifth-order Butterworth low pass filter, the filter range can be used in Bluetooth, cdma2000, wideband CDMA, and IEEE 802.11a/b/g/n wireless LAN. Using floating transistor architecture in the input stage of OTA can effectively increase the THD performance. Using MOS transistors operating in triode region and combined with current multiplier can achieve the voltage-to-current conversion. Using the trans-linear loop can reach a wide tunable range, and the OTA operating in weak inversion region can significantly reduce the transconductance. Implementation is to use the TSMC 0.18£gm CMOS process. Simulation results show that the successful operation of this filter can be between 650 kHz ~ 22MHz frequency range. The filter may have compatibility in different wireless communication applications. 14.5mW to 17.5mW, respectively, is the smallest to the largest power consumption. The supply voltage is 1.2 volts.
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The Application of 75 Rule in Stock Index Trading StrategiesKan, Yi-Li 23 June 2012 (has links)
Stationarity is an essential property to portfolio return in the past statistical arbitrage strategy, this article uses Neo-75 rule, momentum effect, properties as independent and identically distribution and stationarity in error term, in one asset and in the very short holding period. The result in out sample period owning positive cumulative return.
The finding suggests individual investors use this strategy in higher efficiency market to avoid invalidation in our model.
This article surveyed CAC40, DJI, HangSeng, NASDAQ, Nikkei225, Shanghai and TWII indices. All the excess returns in out sample periods indicate they are exclude weak form of efficient market.
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Some characterization results related to k-record valuesLin, Chen-yi 01 July 2004 (has links)
In this paper, let be a sequence of k-record values from a population with common distribution function F. We will characterize the continuous (or discrete) distribution function F by the conditional expectation functions. We also study the necessary and sufficient conditions such that the conditional expectations of k-record values hold for some distribution function F. A corresponding characterization based on weak k-record values and some related characterizations are also investigated.
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Analysis Of Support Design Practice At Elmalik Portals Of Bolu TunnelAscioglu, Gokhan 01 December 2007 (has links) (PDF)
A completed part of the Bolu Tunnel at Elmalik side collapsed during the 1999 Dü / zce earthquake. In order to by-pass the collapsed section, a new tunnel route was determined. 474 meters of the new route, including two portals and double tubing, crossed through the weak to very weak rock units with intersecting fault gouge, excavated from Elmalik side. In this study, the characteristics of the rock masses and support classes are determined for new route of the Elmalik Side. Then, during the tunnel excavation, the deformations of temporary and permanent support systems were precisely measured and recorded. The support system properties as determined from NATM were analyzed by two dimensional convergence confinement method using the numerical RocSupport software.
As a result of this study, for weak ground tunneling, duration of primary support installation should be kept at minimum. Besides that, temporary support measures such as forepoling, face sealing and temporary invert have an important role in controlling deformations before the primary support installation. With the application of temporary supports, loading on the permanent support, and hence the final deformation of the excavation, was found to be reduced significantly. Application of rigid lining was found to be necessary in order to prevent long-term deformations in weak ground tunnels, even though it is contradictory to the NATM philosophy.
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A study of discrepancy results in partially ordered setsHoward, David M. 20 May 2010 (has links)
In 2001, Fishburn, Tanenbaum, and Trenk published a pair of papers that introduced the notions of linear and weak discrepancy of a partially ordered set or poset. Linear discrepancy for a poset is the least k such that for any ordering of the points in the poset there is a pair of incomparable points at least distance k away in the ordering. Weak discrepancy is similar to linear discrepancy except that the distance is observed over weak labelings (i.e. two points can have the same label if they are incomparable, but order is still preserved). My thesis gives a variety of results pertaining to these properties and other forms of discrepancy in posets. The first chapter of my thesis partially answers a question of Fishburn, Tanenbaum, and Trenk that was to characterize those posets with linear discrepancy two. It makes the characterization for those posets with width two and references the paper where the full characterization is given. The second chapter introduces the notion of t-discrepancy which is similar to weak discrepancy except only the weak labelings with
at most t copies of any label are considered. This chapter shows that determining a poset's t-discrepancy is NP-Complete. It also gives the t-discrepancy for the disjoint sum of chains and provides a polynomial time algorithm for determining t-discrepancy of semiorders. The third chapter presents another notion of discrepancy namely total discrepancy which minimizes the average distance between incomparable elements. This chapter proves that finding this value can be done in polynomial time unlike linear discrepancy and t-discrepancy. The final chapter answers another question of Fishburn, Tanenbaum, and Trenk that asked to characterize those posets that have equal linear and weak discrepancies. Though determining the answer of whether the weak discrepancy and linear discrepancy of a poset are equal is an NP-Complete problem, the set of minimal posets that have this property are given. At the end of the thesis I discuss two other open problems not mentioned in the previous chapters that relate to linear discrepancy. The first asks if there is a link between a poset's dimension and its linear discrepancy. The second refers to approximating linear discrepancy and possible ways to do it.
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Stock Market Efficiency : A Test of the Swedish Stock Market in the Weak FormEkdahl, Malin, Aram Roya, Emilia January 2003 (has links)
<p>Background: A well-known study, similar to ours, was made in 1985 in America, showing that "loser" portfolios outperformed the market while "winner" portfolios earned less return than the market. This finding is not in accordance with the theory of efficient markets. If a market is efficient, there should be no possibility of making sustainable excess returns and prices should follow a random walk. </p><p>Purpose: The purpose of this thesis is to study a "winner" portfolio and a "loser" portfolio in order to establish whether the Swedish stock market is efficient in the weak form. We will study the efficiency of the A-list at Stockholm Stock Exchange. </p><p>Delimitations: We test efficiency of the Swedish stock market in the weak form. Our investigation comprises stocks registered on the A-list of the Stockholm Stock Exchange. We do not take tax- and transactions costs into consideration in this study. </p><p>Methodology: "Winner" and "loser" portfolios are formed for the period 1997- 2002. We keep the portfolios during a test period of one year, i.e. form new portfolios at the end of each year. The first winner and loser portfolios are selected on the last day of trading in 1996 and the last two portfolios are selected on the last day of trading in 2001. </p><p>Results: Our result indicates that the Swedish stock market is efficient in the weak form during the period 1997-2002.</p>
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The weak language learner : a study of ways of taking weak language learners into consideration in classAxelsson, Susanna January 2007 (has links)
<p>English is taught as a compulsory second language in Swedish schools and is one of three core subjects needed to be passed in order to receive a leaving certificate. Statistics show that 6.9% of the students do not aquire proficiency enough to receive a G (pass) in English in grade nine. The aim of this study is to investigate to what extent weak language learners are considered in the English classroom and if compensatory aids are used to further support their learning conditions. The method used for the study is qualitative interviews which were semi-structured. Four interviews with English teachers were conducted within the same municipality.</p><p>The result shows that there are aspects that can be considered in order to provide better opportunities for weak language learners within the English classroom as well as outside the English classroom. Some teachers find it difficult to separate lack of motivation from lack of knowledge which makes discovering the students as early as possible important. In the English classroom weak language learners can be supported by smaller discussion groups since one problem seems to be oral skills. A connection to Swedish can be observed and students with difficulties in reading and writing in their native language experience more problems when learning English. The interviewees state the importance of first focusing on oral skills in the target language, before introducing written skills.</p><p>Regarding support outside the English classroom the investigation shows that optional English, parents and homework are important features. In the optional English class weaker language learners get an opportunity to speak and revise previous blanks of knowledge. Parents are important for showing their children that they find English important but also for supporting the children while doing homework.</p><p>Concerning compensatory aids, most teachers did not use them nor had they knowledge enough about available aids. The most frequently used aid was a CD where texts are recorded.</p>
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Time performance comparison in determining the weak parts in wooden logsAkhtar, Naeem, Alzghoul, Ahmad January 2009 (has links)
<p>The steadily increasing demand of wood forces sawmills to increase the efficiency and effectiveness of their equipments. The weak parts and the twist in wooden logs have been documented as the most common and crucial defect in sawn lumber.</p><p>In this thesis we are going to implement a program which is able to determine the weak parts in wooden logs. The implementation will be in two languages C++ and Matlab. Parts of the program are going to be implemented sometimes by C++ and sometimes by Matlab therefore different designs are going to be tested. The aim of this thesis is to check whether these designs will meet the real time bound of 10 m/s.</p><p>The result shows that there is a huge difference in time performance for the different designs. Therefore, different discretization levels were used in order to meet the deadline of 10m/s. We found that in order to get better speed one should calculate the matrix for the function <em>F </em>and the Jacobian function <em>J </em>by using C++ not by Matlab. Also we found that when we called functions from one language to another an extra time is added.</p>
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On the convergence of random functions defined by interpolationStarkloff, Hans-Jörg, Richter, Matthias, vom Scheidt, Jürgen, Wunderlich, Ralf 31 August 2004 (has links) (PDF)
In the paper we study sequences of random functions which are defined by some
interpolation procedures for a given random function. We investigate the problem
in what sense and under which conditions the sequences converge to the prescribed
random function. Sufficient conditions for convergence of moment characteristics, of
finite dimensional distributions and for weak convergence of distributions in spaces
of continuous functions are given. The treatment of such questions is stimulated by
an investigation of Monte Carlo simulation procedures for certain classes of random
functions.
In an appendix basic facts concerning weak convergence of probability measures
in metric spaces are summarized.
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The invisible handshake: Interpreting the job-seeking communication of foreign-born chinese in the U.S.Gao, Hongmei 01 June 2005 (has links)
Building upon Granovetters well-known study of the job search behaviors of white males, this research extended the degree to which his findings apply across cultures to Chinese minorities, and across time to the Internet age. Using quantitative and qualitative data collected through systematic observation, questionnaire surveys, and in-depth interviews, this research investigated the impact of culture, Internet usage, gender and age on the communication patterns of foreign-born Chinese jobseekers in the U.S. It is found that jobseekers adopt either one or a combination of traditional (printed publications and direct application), institutional (the Internet, job fairs, and employment agencies), and personal (personal network) approaches. Within the institutional approach, the Internet job search strategy is a rsing preference among younger jobseekers.
Through the personal approach, jobseekers enjoy four benefits of personal networks: information, trust building, position creation, and job market expansion. Across culture, guanxi, the Chinese version of the personal network is compared and contrasted with its American counterpart. Further, Granovetters argument about the strength of weak ties holds true in todays Internet age. Job-leading weak ties are usually those infrequently contacted professional and social connections working in targeted organizations at the time of a job search. Meanwhile, Chinese jobseekers mainly encounter six obstacles in the U.S.: racial discrimination, cultural obstacle, linguistic obstacle, insufficient network, immigration background, and an intercultural communication gap.
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