Spelling suggestions: "subject:"mixed"" "subject:"fixed""
121 |
Analysis of Fix‐point Aspects for Wireless Infrastructure SystemsGrill, Andreas, Englund, Robin January 2009 (has links)
<p>A large amount of today’s telecommunication consists of mobile and short distance wireless applications, where the effect of the channel is unknown and changing over time, and thus needs to be described statistically. Therefore the received signal can not be accurately predicted and has to be estimated. Since telecom systems are implemented in real-time, the hardware in the receiver for estimating the sent signal can for example be based on a DSP where the statistic calculations are performed. A fixed-point DSP with a limited number of bits and a fixed binary point causes larger quantization errors compared to floating point operations with higher accuracy.</p><p>The focus on this thesis has been to build a library of functions for handling fixed-point data. A class that can handle the most common arithmetic operations and a least squares solver for fixed-point have been implemented in MATLAB code.</p><p>The MATLAB Fixed-Point Toolbox could have been used to solve this task, but in order to have full control of the algorithms and the fixed-point handling an independent library was created.</p><p>The conclusion of the simulation made in this thesis is that the least squares result are depending more on the number of integer bits then the number of fractional bits.</p> / <p>En stor del av dagens telekommunikation består av mobila trådlösa kortdistanstillämpningar där kanalens påverkan är okänd och förändras över tid. Signalen måste därför beskrivas statistiskt, vilket gör att den inte kan bestämmas exakt, utan måste estimeras. Eftersom telekomsystem arbetar i realtid består hårdvaran i mottagaren av t.ex. en DSP där de statistiska beräkningarna görs. En fixtals DSP har ett bestämt antal bitar och fast binärpunkt, vilket introducerar ett större kvantiseringsbrus jämfört med flyttalsoperationer som har en större noggrannhet.</p><p>Tyngdpunkten på det här arbetet har varit att skapa ett bibliotek av funktioner för att hantera fixtal. En klass har skapats i MATLAB-kod som kan hantera de vanligaste aritmetiska operationerna och lösa minsta-kvadrat-problem.</p><p>MATLAB:s Fixed-Point Toolbox skulle kunna användas för att lösa den här uppgiften men för att ha full kontroll över algoritmerna och fixtalshanteringen behövs ett eget bibliotek av funktioner som är oberoende av MATLAB:s Fixed-Point Toolbox.</p><p>Slutsatsen av simuleringen gjord i detta examensarbete är att resultatet av minsta-kvadrat-metoden är mer beroende av antalet heltalsbitar än antalet binaler.</p> / fixtal, telekommunikation, DSP, MATLAB, Fixed-Point Toolbox, minsta-kvadrat-lösning, flyttal, Householder QR faktorisering, saturering, kvantiseringsbrus
|
122 |
Design and Development of 75 mm Fixed-Wing Nano Air VehiclePushpangathan, Jinraj V January 2017 (has links) (PDF)
This thesis deals with the design and development of a 75 mm fixed-wing nano-air vehicle (NAV). The NAV is designed to fit inside a cube with each side measuring 75 mm. The range and endurance of the NAV are 300 m and 2-3 minutes, respectively. The high-wing horizontal tailless NAV has a take-off weight of 19.5 g. The battery-powered single propeller NAV has two control surfaces in the form of elevator and rudder.
This thesis contains a detailed account of the airfoil selection, selection of the configuration of NAV and the longitudinal, lateral and directional aerodynamic characterization of the NAV. The development of one of the lightweight autopilot hardware which weighs 1.8 g is also given in detail. The development of non-linear equations of motion of NAV including thrust and coupling effects is also discussed. The effects of the gyroscopic coupling and counter torque on the linear dynamics of the NAV are analyzed by conducting a parametric study about the variation of the eigenstructure attributable to the varying degree of coupling in the system matrix of the linear coupled model.
A robust simultaneously stabilizing output feedback controller is synthesized for stabilizing the plants of the NAV. The synthesizing of the robust simultaneously stabilizing output feedback controller is based on a frequency-shaped central plant. A new procedure is developed to determine the frequency-shaped central plant utilizing the v-gap metric between the plants, the frequency-shaping of the plants with the pre and post compensators and the robust stabilization theory. An optimization problem is formulated to obtain these compensators. A novel iterative algorithm is developed to acquire the compensators by solving the optimization problem. Thereafter, an iterative algorithm is developed to find an output feedback controller for robust simultaneous stabilization by blending the existing features of robust stability condition of right co-prime uncertainty model of the frequency-shaped central plant, the maximum v-gap metric of the frequency-shaped central plant, H∞ loop-shaping and eigenstructure assignment algorithm for output feedback using the genetic algorithm. The six-degree-of-freedom numerical and hardware-in-loop simulations (HILS) of closed-loop non-linear and linear plants of NAV are performed to assess the performance of the controller and to validate the control algorithm implemented in the autopilot.
The airworthiness of the aircraft is tested by conducting flight trials in radio-controlled (RC) mode without including the autopilot. The successful RC flight trial of the NAV indicates airworthiness of the aircraft which aided in freezing the configuration. This is one of the smallest fixed wing aerial vehicle that was successfully flown till date.
|
123 |
The Impact of Emission Trading System on Economic Growth and Gross Fixed Capital Formation / Utsläppshandelns påverkan på ekonomisk tillväxt och investeringarWall, Hanna January 2022 (has links)
Policymakers' action of mitigating and slowing down the continued increase of carbon emission is a significant global priority. One way to internalise the negative externality of pollution is to put a price on greenhouse gases and use the market-based approach of emission trading systems. On the other hand, according to economic reasoning, pollution is an essential tool for economic development. This paper aims to investigate the economic effects of introducing the first international emission trading system of greenhouse gases, the EU emission trading system, by observing the economic growth and gross fixed capital formation. Mankiw, Romer, and Wiel's (1992) theory is utilised in this study and based on cross-country and cross-state panel data between 1999-2012, an empirical analysis using the fixed effects model was followed. The finding shows that the EU emission trading system has a negative effect on the growth of real gross domestic product per capita compared to states and countries not participating in an emission trading system. In addition, the first phase results having a positive effect and the second phase has a negative effect on the economic growth compared to states and countries not participating in an emission trading system. There is no statistical evidence of the effect on gross fixed capital formation as a percentage share of GDP. Organisations can use the findings to decide whether developing countries can afford the consequence of an implemented emission trading system since it tends to slow down growth. However, further research needs to consider the effect of the financial crisis of 2008 and the interpretation of the EU emission trading scheme.
|
124 |
Gebruik van opsies in vasterentedraende effekte om beleggingsrisiko te beperkMynhardt, Ronald Henry 01 1900 (has links)
Opbrengskoerse van vasterentedraende effekte verander as gevolg van
veranderings in vraag en aanbod op die kapitaalmark. Die veranderinge in
opbrengskoerse bei'nvloed die pryse van vasterentedraende effekte, asook van
die opsies op hierdie effekte en stel beleggers in hierdie instrumente bloot aan
beleggingsrisiko.
Hierdie studie ondersoek die uitwerking van veranderings in die opbrengskoerse
op die pryse van vasterentedraende eff ekte en opsies indien geen verskansing
teen beleggingsrisiko toegepas word nie. Verder word verskillende
verskansingstegnieke vergelyk ten einde te bepaal welke tegniek
beleggingsrisiko die mees doeltreffendste kan beperk.
Die studie toon aan dat dit wenslik is om beleggings en vasterentedraende
effekte en opsies teen beleggingsrisiko te verskans. Empiriese toetse is op
verskeie tegnieke gedoen om te bepaal watter verskansingstegnieke
beleggingsrisiko die doeltreffendste kan beperk.
Die gevolgtrekking is dat beleggingsrisiko inderdaad doeltreffend beperk kan
word. Vir elke posisie in vasterentedraende en opsies is 'n spesifieke
verskansingstegniek gei'dentifiseer om sodanige posisie doeltreffend in terme van
winsgewendheid te verskans. / Yield on fixed interest bearing securities change as a result of changes in the
supply and demand in the capital market. These changes in the yield influence
the prices of fixed interest securities, as well as options on fixed interest
securities and expose .investors in these instruments to investment risk.
This study investigates the effect of changes in yield on the prices of fixed
interest securities and options if no hedging against investment risk is instituted.
Different techniques are compared to establish which technique will restrict
investment risk effectively.
This study shows that it is desirable to hedge investments in fixed interest
securities and options against investment risk. Empirical tests were conducted
on a variety of techniques to establish which technique would restrict investment
risk effectively.
The conclusion is that investment risk can be limited. A specific technique has
been identified for each position in fixed interest securities and options that can
hedge such a position effectively against investment risk in terms of
profitability. / Business Management / MCOM (Bedryfsekonomie)
|
125 |
On Fixed Point Convergence of Linear Finite Dynamical SystemsLindenberg, Björn January 2016 (has links)
A common problem to all applications of linear finite dynamical systems is analyzing the dynamics without enumerating every possible state transition. Of particular interest is the long term dynamical behaviour, and if every element eventually converges on fixed points. In this paper, we study the number of iterations needed for a system to settle on a fixed set of elements. As our main result, we present two upper bounds on iterations needed, and each one may be readily applied to a fixed point system test. The bounds are based on submodule properties of iterated images and reduced systems modulo a prime.
|
126 |
Regulating stepping during fixed-speed and self-paced treadmill walkingZhao, Xueyan, active 21st century 09 October 2014 (has links)
Background: Treadmill walking should closely simulate overground walking for research validation and optimal skill transfer. Traditional fixed-speed treadmill (FS) walking may not simulate natural walking because of the fixed belt speed and lack of visual cues. Self-paced (SP) treadmill walking, especially feedback controlled SP treadmill walking, enables close-to-real-time belt speed changes with users' speed changes. Different sensitivity levels of SP treadmill feedback determine how fast the treadmill respond to user's speed change. Few studies have examined the differences between FS and SP treadmill walking, or the difference between sensitivity levels of SP treadmills, and their methods were questionable because of averaging kinematics and kinetics parameters, and failing to examine directly treadmill and subjects' speed data. This study compared FS with two SP modes with variation of treadmill speed and user's speed as dependent variables. Method: Thirteen young healthy subjects participated. Subjects walked on a motorized split-belt treadmill under FS, high sensitivity SP (SP-H) and low sensitivity SP (SP-L) conditions at normal walking speed. Root mean square error (RMSE) for subject's pelvis global speed (Vpg), pelvis speed with respect to treadmill speed (Vpt), and treadmill speed (Vtg) data were collected for all trials. Results: Significant condition effects were found between FS and the two SP modes in all RMSE values (p < 0.001). The two sensitivity levels of SP had similar speed patterns. Large subject × condition interaction effects were found for all variables (p < 0.001). Only small subject effects were found. Conclusions: The results of the study reveal different walking patterns between FS and SP. However, the two sensitivity levels failed to differ much. More habituation time may be needed for subjects to learn to optimally respond to the SP algorithm. Future work should include training subjects for more natural responses, applying a feed-forward algorithm, and testing the effect of optic flow on FS and SP speed variation. / text
|
127 |
Kainų stabilumo užtikrinimas esant fiksuotam valiutos kursui / Prices Stability Issue Under Fixed Exchange RateKiselis, Jonas 17 June 2009 (has links)
Jonas Kiselis, Kainų stabilumo užtikrinimas esant fiksuotam valiutos kursui [Rankraštis]: bakalauro baigiamasis darbas: economika. Vilnius, ISM Vadybos ir ekonomikos universitetas, 2009.
Šis darbas apie kainų stabilumo užtikrinimą ir infliacijos problemas, iškylančias valstybėms, palaikančioms fiksuotą savo nacionalinės valiutos kursą kitos inkaro valiutos atžvilgiu. Darbe analizuojama dviejų ekonominių regionų ekonominė padėtis šiuo aspektu: Baltijos šalių ir Įlankos Bendradarbiavimo Tarybos. Šie du regionai palyginami, išnagrinėjama, ką jie turi bendro ir kuo skiriasi savo ekonomikų specifika.
Pirmoje dalyje analizuojama esama situacija praėjusio laikotarpio kontekste, analizuojamos pagrindinės priežastys, labiausiai lemiančios kainų nestabilumą ir infliacijos lygį Baltijos ir ĮBT ekonominių regionų šalyse. Bandomos pasverti teigiamos ir neigiamos fiksuoto šių valstybių valiutų kursų pasėkmės jų ekonomikoms.
Antrojoje dalyje iš teorinės pusės apžvelgiama kainų stabilumo ir infliacijos problematika ekonomikose, kurių valiutos susietos su „inkaru“ (kitos valstybės valiuta arba valiutų krepšeliu). Aiškinamasi, kokių priemonių turi būti imamasi siekiant išlaikyti stabilų kainų lygį ir žemą infliaciją valstybėje, palaikančioje fiksuotą savo nacionalinės valiutos kursą ir apskritai, kokiais atvejais valstybei verta rinktis fiksuotą, o kokiais plaukiojantį valiutos kurso mechanizmą.
Trečioje dalyje atliekamas tyrimas, kuriame, naudojantis tiesine regresine analize, bandoma... [toliau žr. visą tekstą] / Jonas Kiselis, Prices Stability Issue Under Fixed Exchange Rate [Rankraštis]: bakalauro baigiamasis darbas: economics. Vilnius, ISM Vadybos ir ekonomikos universitetas, 2009.
This paperwork is aimed at analysing prices stability and infliation issues arising in economies of countries with fixed exchange rate. Two economic regions‘ economic states are being analysed from attitude of abovementioned issue. These are Baltic states and Gulf Cooperation Council. These two regions are compared, analysed what is general and different by characteristics of their economies.
The first part is dedicated to current situation analysis in context of the past periods of time. The prevailing reasons of prices instability and inflation in the Baltics and GCC are analysed. Both positive and negative consequences of fixed exchange rate are evaluated in these economies.
In the second part, prices stability and inflationary issues are reviewed in a country with economy of fixed exchange rate regime, whose currency is pegged to „anchor“ (currency of another country or a basket of currencies). What remedies need to be taken as an instrument of an economic policy in order to manage sustainable prices stability and low inflation rate in the country of fixed exchange rate. What are the cases when a country has to choose fixed exchange rate and what are the cases for a floating exchange rate regime as an optimal option.
A research is conducted in the third part of this work. Linear regression analyses... [to full text]
|
128 |
Conditions on the existence of unambiguous morphismsNevisi, Hossein January 2012 (has links)
A morphism $\sigma$ is \emph{(strongly) unambiguous} with respect to a word $\alpha$ if there is no other morphism $\tau$ that maps $\alpha$ to the same image as $\sigma$. Moreover, $\sigma$ is said to be \emph{weakly unambiguous} with respect to a word $\alpha$ if $\sigma$ is the only \emph{nonerasing} morphism that can map $\alpha$ to $\sigma(\alpha)$, i.\,e., there does not exist any other nonerasing morphism $\tau$ satisfying $\tau(\alpha) = \sigma(\alpha)$. In the first main part of the present thesis, we wish to characterise those words with respect to which there exists a weakly unambiguous \emph{length-increasing} morphism that maps a word to an image that is strictly longer than the word. Our main result is a compact characterisation that holds for all morphisms with ternary or larger target alphabets. We also comprehensively describe those words that have a weakly unambiguous length-increasing morphism with a unary target alphabet, but we have to leave the problem open for binary alphabets, where we can merely give some non-characteristic conditions. \par The second main part of the present thesis studies the question of whether, for any given word, there exists a strongly unambiguous \emph{1-uniform} morphism, i.\,e., a morphism that maps every letter in the word to an image of length $1$. This problem shows some connections to previous research on \emph{fixed points} of nontrivial morphisms, i.\,e., those words $\alpha$ for which there is a morphism $\phi$ satisfying $\phi(\alpha) = \alpha$ and, for a symbol $x$ in $\alpha$, $\phi(x) \neq x$. Therefore, we can expand our examination of the existence of unambiguous morphisms to a discussion of the question of whether we can reduce the number of different symbols in a word that is not a fixed point such that the resulting word is again not a fixed point. This problem is quite similar to the setting of Billaud's Conjecture, the correctness of which we prove for a special case.
|
129 |
Inclusion and professionalism : reducing fixed term exclusions in a south west secondary school : a cultural historical activity theory study of a disciplinary inclusion roomGilmore, Gwendoline Julia January 2010 (has links)
This thesis presents an exploration of the nature, extent and characteristics of a disciplinary Inclusion Room (IR), from the perspectives of students and staff in a South West secondary school. Over the past five years, this school has significantly reduced fixed term exclusions and improved school attainment against Local Authority averages. This research presents an organisational response to a socio-cultural problem and the paradoxical lenses of social inclusion and discipline. The research uses Cultural Historical Activity Theory (CHAT) as a theoretical and methodological framework. I explore inclusion and professionalism using the perspectives of nine students who entered disciplinary IR and nine staff who knew the students. Inclusion constructs explored include participation, equality and diversity. Professionalism is deliberated through a continuum of managerial control/discretionay judgement, individualistic models/collegial approaches and bureaucratic/continuous learning dimensions. Mixed methods used include document analysis, an on-line questionnaire, student and staff interviews, visual timelines and observations of the students in classrooms. The analysis of IR considers primary, secondary and tertiary contradictions along with disciplinary rules, community and division of labour/power constructs amongst participants to develop a rich understanding of the context. Exploratory data, in the form of a questionnaire, suggests that the students and staff broadly share understanding of inclusion policy, practice and culture in this school. Interviews, further informed by examination of documents, student timelines and observations, show how a disciplinary IR is integrated into, and complements, educational processes; participation (being there), equality and diversity, within the school. Professionalism is characterised by discretionary lenses, collegial working and continuous learning governed by problem solving to support that educational vision. Findings from this work are generalisable as the research develops experience of the school in a naturalistic manner and is illustrative of expectations rather than formal predictions. Nevertheless, schools can use the findings to consider how a disciplinary IR can complement educational processes through increasing participation, equality and diversity. Goals for inclusion can be enhanced through collaborative partnerships and active, ongoing engagement amongst students and staff to develop the educational experience.
|
130 |
Immediate and subsequent effects of fixed-time food presentations on automatically maintained mouthing.Simmons, Jason N. 12 1900 (has links)
Several studies have demonstrated that fixed-time (FT) schedules of stimulus delivery can function to reduce a variety of behaviors. The purpose of this study was to evaluate the immediate and subsequent effects of FT food deliveries on mouthing. In Phase 1, a preference assessment showed that caramel popcorn, chocolate cookies and pretzels were highly preferred food items. Thus, providing the basis for use of food items during treatment. In Phase 2, a functional analysis showed that mouthing was a nonsocially maintained problem behavior. Phase 3 demonstrated the use of FT schedules of food deliveries as treatment for nonsocially maintained mouthing. Results indicated that FT schedules of food significantly reduced mouthing. In addition, levels of mouthing observed during post-FT observations were reliably lower than pre-FT observations. Treatment effects, operative mechanisms responsible for the treatment effects and the experimental arrangement used to investigate varying FT schedules are discussed.
|
Page generated in 0.0308 seconds