4,219 research outputs found
Sensorless action-reaction-based residual vibration suppression for multi-degree-of-freedom flexible systems
This paper demonstrates the feasibility of controlling motion and vibration of a class of flexible systems with inaccessible or unknown outputs through measurements taken from their actuators which are used as single platforms for
measurements, whereas flexible dynamical systems are kept free from any attached sensors. Based on the action reaction law of dynamics, the well-known disturbance observer is used to determine the incident reaction forces from these dynamical systems on the interface planes with their actuators. Reaction
forces are considered as feedback-like signals that can be used as alternatives to the inaccessible system outputs. The sensorless action reaction based motion and vibration control technique is implemented on a flexible system with finite modes and all results are verified experimentally
A study of the effect of addition of copper compounds to soils on the metabolism of nitrogen
Imperial Users onl
Five Quantum Algorithms Using Quipper
Quipper is a recently released quantum programming language. In this report,
we explore Quipper's programming framework by implementing the Deutsch's,
Deutsch-Jozsa's, Simon's, Grover's, and Shor's factoring algorithms. It will
help new quantum programmers in an instructive manner. We choose Quipper
especially for its usability and scalability though it's an ongoing development
project. We have also provided introductory concepts of Quipper and
prerequisite backgrounds of the algorithms for readers' convenience. We also
have written codes for oracles (black boxes or functions) for individual
algorithms and tested some of them using the Quipper simulator to prove
correctness and introduce the readers with the functionality. As Quipper 0.5
does not include more than \ensuremath{4 \times 4} matrix constructors for
Unitary operators, we have also implemented \ensuremath{8 \times 8} and
\ensuremath{16 \times 16} matrix constructors.Comment: 27 page
An Investigation of Significant Factors Influencing Western Australian Wool Producers to Produce Wool: A Structural Equation Modelling Approach
Why Australian wool producers remained in the business despite the hardship they have experienced for much of the 1990s from low prices of wool? This question was raised frequently by research scientists and policymakers of the wool industry. A recent exploratory study gives a notion that Australian wool production could be a 'lifestyle' choice and/or a choice other than economic reasons. To validate this notion this paper investigates the factors that drive and motivate the Western Australian wool producers, as identified in the exploratory study, by applying a Structural Equation Modelling approach. An innovative mixed research method is adopted in this study. Telephone survey is conducted among a random selection of 290 wool producers in WA. The results suggest that despite some expectations lifestyle factor is not significant in influencing WA wool producers to produce wool. Income, input factor and personal motivation are significant predictors of wool production by WA wool producers. Implications of the results are discussed.Livestock Production/Industries, C21, L2, L7, Q10,
Inflation Targeting as the Monetary Policy Framework: Bangladesh Perspective
Inflation targeting strategy has become a widely accepted monetary policy framework in many countries all over the world. Our study finds that the central bank of Bangladesh is neither inflation targeting nor does follow any other rule-guided monetary policy, rather the policy is formulated with substantial discretion under the guidelines of donor agencies. This paper provides the evidence that monetary sector of Bangladesh economy has gained considerable degree of maturity and fulfils a number of prerequisites to adopt inflation targeting strategy. Using data over 1980-2010 we estimate an error correction model in order to examine if interest rate policy could fight the inflation. This is evident that deviation in inflation from target can be corrected via the changes in interest rate. Empirical findings jointly with few descriptive statistics provide strong evidence to recommend inflation targeting as the monetary policy strategy for Bangladesh.Bangladesh, Inflation Targeting, Monetary Policy.
Sensorless torque/force control
Motion control systems represent a main subsystem for majority of processing systems that can be found in the industrial sector. These systems are concerned with the actuation of all devices in the manufacturing process such as machines, robots, conveyor systems and pick and place mechanisms such that they satisfy certain motion requirements, e.g., the pre specified reference trajectories are followed along with delivering the proper force or torque to the point of interest at which the process occurs. In general, the aim of force/torque control
is to impose the desired force on the environment even if the environment has dynamical motion
Inter-firm Relationships and Performance Factors in the Australian Beef Supply Chain: Implications for the Stakeholders
Recent study by Meat & Livestock Australia revealed that cost competitiveness and market development issues in supply chain are the major factors for a long term decline of the Australian Beef industry. This study, based on the explanation of transaction cost theory argues that competitive performance of an industry depends on improving cost efficiency across the whole of supply chain, the underlying value chain, and the relationship among the stakeholders in the industry. With a main objective to investigate the underlying factors of developing competent inter-firm relationship that influence the supply chain performance and competitiveness, this study presents details of a survey carried out and tests the hypothesis that inter-organizational relationships in supply chain and its antecedents have impact on the performance of Australian beef industry and thus have impact on the competitiveness of the industry. Data were collected through a telephone survey of 315 firms in the beef industry from the states of Western Australia and Queensland. The sample respondents were categorized as input suppliers, beef-cattle producers, processors, retailers/exporters, and wholesalers. The data were analysed using the partial least square based structural equation modelling. PLS analysis reveals that âTransaction Climateâ is the strongest determinants of developing a competent relationship, while negotiation power, presence of industry competitors, and the degree of vertical coordination significantly influence the relationship strength. Findings also demonstrate that relationship strength is the most prevalent source of performance and competitiveness, while SC performance highly positively influences the Competitiveness of beef industry. Thus this study identifies significant antecedents and consequences of Supply Chain Performance in Australian beef industry, which are strategic and extremely important information for beef producers, processors, retailers, and other stakeholders for appropriate planning and benchmarking.Beef Supply Chain, Agribusiness Management, Supply Chain Management, Agribusiness,
Advanced logic gates for ultrafast network interchanges
By overcoming speed bottlenecks from electronic switching as well as optical/electronic conversions, allâoptical logic gates can permit further exploitation of the nearly 40 THz of bandwidth available from optical fibers. We focus on the use of optical solitons and allâoptical logic gates to implement ultrafast ââinterchangesââ or switching nodes on packet networks with speeds of 100 Gbit/s or greater. For example, allâoptical logic gates have been demonstrated with speeds up to 200 Gbit/s, and they may be used to decide whether to add or drop a data packet. The overall goal of our effort is to demonstrate the key enabling technologies and their combination for header processing in 100 Gbit/s, timeâdivisionâmultiplexed, packed switched networks. Solitonâbased fiber logic gates are studied with the goal of combining attractive features of solitonâdragging logic gates, nonlinear loop mirrors, and erbiumâdoped fiber amplifiers to design logic gates with optimum switching energy, contrast ratio, and timing sensitivity. First, the experimental and numerical work studies lowâlatency soliton logic gates based on frequency shifts associated with crossâphase modulation. In preliminary experiments, switching in 15 m long lowâbirefringent fibers has been demonstrated with a contrast ratio of 2.73:1. Using dispersionâshifted fiber in the gate should lower the switching energy and improve the contrast ratio. Next, the lowâbirefringent fiber can be crossâspliced and wrapped into a nonlinear optical loop mirror to take advantage of mechanisms from both soliton dragging and loop mirrors. The resulting device can have low switching energy and a timing window that results from a combination of soliton dragging and the loop mirror mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87474/2/605_1.pd
Biodétection de Legionella pneumophila par biocapteur à photocorrosion digitale à base de peptide antimicrobien
La dĂ©tection de bactĂ©ries pathogĂšnes par culture microbienne est lente, nĂ©cessite un milieu de culture spĂ©cifique pour garantir la croissance de certaines souches bactĂ©riennes fastidieuses telle que Legionella pneumophila (L. pneumophila) et en plus pourrait ne pas dĂ©celer les bactĂ©ries viables mais non cultivables mais restant dangereuse en termes de pathogĂ©nicitĂ©. Par consĂ©quent, lâusage de biocapteurs pour la dĂ©tection de L. pneumophila serait, potentiellement, une approche attrayante permettant une dĂ©tection prĂ©cise et rapide. Cependant, la sensibilitĂ© et la spĂ©cificitĂ© des biocapteurs dĂ©pendent fortement des molĂ©cules de bioreconnaissance utilisĂ©es. Jusqu'Ă prĂ©sent, diffĂ©rents ligands tels que les anticorps, les enzymes, les acides nuclĂ©iques fonctionnels (aptamĂšres) et les bactĂ©riophages ont Ă©tĂ© utilisĂ©s comme Ă©lĂ©ments de bioreconnaissance. En raison de leur haute spĂ©cificitĂ©, Les anticorps de mammifĂšres ont Ă©tĂ© largement employĂ©s pour le dĂ©veloppement de divers biocapteurs. Cependant, les anticorps sont connus pour souffrir de la variabilitĂ© des lots produits et d'une stabilitĂ© limitĂ©e, ce qui rĂ©duit l'usage et la constance des performances des biocapteurs Ă base d'anticorps. Au cours des derniĂšres annĂ©es, les peptides antimicrobiens (PAM) ont Ă©tĂ© de plus en plus investiguĂ©s pour des applications thĂ©rapeutiques en plus dâĂȘtre considĂ©rĂ©s comme des ligands de bioreconnaissance prometteurs en raison de leur grande stabilitĂ© et leurs fortes rĂ©activitĂ©s aux bactĂ©ries. Dans le but dâamĂ©liorer les performances du biocapteur Ă DIP, notre hypothĂšse reposait sur lâusage de bioarchitectures Ă base de PAM Ă courte sĂ©quence pour une capture efficace des bactĂ©ries et une dĂ©tection considĂ©rablement amĂ©liorĂ©e en raison du transfert de charge plus facilitĂ©e vers dans la biopuce Ă base de semiconducteur III-V. Dans la premiĂšre phase du projet, nous avons Ă©valuĂ© un biocapteur Ă DIP consistant en une puce dâarsĂ©niure de gallium/arsĂ©niure de gallium aluminium (GaAs/AlGaAs) fonctionnalisĂ©e par le warnericine RK pour la dĂ©tection directe in situ de L. pneumophila dans lâeau. Nous avons dĂ©montrĂ© une dĂ©tection linĂ©aire de L. pneumophila pour des concentrations allant de 103 Ă 106 CFU/mL. De plus, le nombre relativement important d'interfaces constituant la bioarchitecture dâun tel biocapteur pourrait affecter sa reproductibilitĂ© et sa sensibilitĂ©. Dans ce cas, la couche de bioreconnaissance est plus mince (~ 2 nm) permettant une distance plus courte entre les bactĂ©ries et la surface du biocapteur, ce qui pourrait jouer un rĂŽle important dans la promotion du transfert de charge entre les bactĂ©ries et la biopuce, et ainsi nous avons pu dĂ©montrer une dĂ©tection efficace de L. pneumophila Ă une concentration de 2 x 102 CFU/mL. Cette configuration a permis dâatteindre des LODs de 50 et 100 UFC/mL, respectivement pour de lĂ©gionnelle dans du PBS et collectĂ©es dâĂ©chantillons dâeau de tour de refroidissement. Nous avons observĂ© une dĂ©tection sĂ©lective de L. pneumophila sĂ©rogroupe 1 (SG1) comparĂ© au sĂ©rogroupe 5 (SG 5). Les biocapteurs Ă photocorrosion digitale (DIP) en configuration sandwich PAM et Ab pourraient ĂȘtre une approche prometteuse pour dĂ©velopper un biocapteur Ă faible coĂ»t, hautement sensible et spĂ©cifique pour la dĂ©tection rapide de L. pneumophila dans lâeau.Abstract: Culture based detection of pathogenic bacteria is time consuming, and needs specific culture medium to identify bacterial strains such as Legionella pneumophila (L. pneumophila) which does not flourish in typical growth medium. Culture based methods cannot detect viable but unculturable bacteria. Therefore, the detection of L. pneumophila with biosensors potentially could be an attractive approach enabling accurate and rapid detection. The sensitivity and specificity of biosensors depend critically on the biorecognition probes employed for the detection. Until now, different elements such as antibodies, enzymes, functional nucleic acids (aptamers) and bacteriophages have been utilized as biorecognition elements. Due to high specificity of antibodies, and the advanced technology of their production, mammalian antibodies have been widely investigated for the development of various biosensors. However, mammalian antibodies are known to suffer from batch-to-batch variation, as well as limited stability, which could reduce the consistent utility of the proposed biosensors. In recent years, antimicrobial peptides (AMPs) have been increasingly investigated for their therapeutic applications. At the same time, AMPs are considered as promising biorecognition ligands due to their high stability and multiple niches for capturing bacteria. The hypothesis was that AMP-based bioarchitectures allows for highly efficient capturing of bacteria, and the short length of the AMP would significantly enhance detection due to limited obstructive charge transfer in the charge sensing biosensor. In the first phase of the project, we investigated a warnericin RK AMP functionalized gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) photonic biosensor for direct detection of L. pneumophila in water environments. This approach allowed for detecting a low to high concentration of L. pneumophila (103 to 106 CFU/mL) with a 103 CFU/mL limit of detection (LOD). In addition, a relatively large number of interfaces constituting the architecture of such biosensors could affect their reproducibility and sensitivity. A thinner biorecognition layer (~2 nm) resulted in a shorter distance between bacteria and the biosensor surface, which played important role in promoting charge transfer between bacteria and biochip. L. pneumophila was detected at concentrations as low of 2 x 102 CFU/mL. This configuration allowed the detection sensitivity of L. pneumophila as low as 50 CFU/mL and 100 CFU/mL in clean water and water originated from cooling tower, respectively, along with the selective detection of whole cell L. pneumophila serogroup 1 (SG1) and serogroup 5 (SG5). The proposed AMP and Ab conjugated sandwich architecture with digital photocorrosion (DIP) biosensors is a promising approach for developing low cost, highly sensitive and specific biosensors for rapid detection of L. pneumophila in water environments
Essays on Government Spending and Sustainable Growth
The first chapter examines the effect of the composition of federal and state government spending on SO2 air concentrations in the US. The results indicate that a reallocation of spending from RME to PME at the state and local level reduces sulfur dioxide concentrations while the composition of federal spending has no effect. A 10% percent increase in the share of PME spending reduces sulfur dioxide concentrations by the range of 3 to 5% for state and local spending. This is a significant effect since sulfur dioxide concentrations have been falling at an annual average rate of 5% from 1980 to 2008. The results are robust to various sensitivity checks.
The second chapter documents the creation of a US government spending allocation database that provides new data on a set of disaggregated government spending categories covering all the states in the US for the period 1983-2008. The data allows for the comparison of federal versus state and local government spending over time on various spending items. This is achieved by categorizing and aggregating expenditures for over 1,500 federal programs and combining data on state and local government spending. The key challenge in separating federal and state and local government spending is the issue of double counting since part of state and local spending is from the federal government. The dataset presented will aid researchers in separately accounting for both state and local, as well as federal spending in future research.
Finally, the third chapter examines fiscal spending and economic growth in the presence of imperfect markets. Political economy factors tend to induce many governments to spend on private goods (RME) to the detriment of spending on social and public goods (PME). This bias in spending patterns is particularly costly for economic growth when capital markets are imperfect. A theoretical model on government spending and growth is developed and linked quite closely to an empirical model. The empirical results fully corroborate the hypothesis that spending biases in favor of non-social subsidies (RME) reduce the rate of economic over the long run. The empirical findings are exceptionally robust
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