945 resultados para Advantages and disadvantages


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A nonlinear general predictive controller (NLGPC) is described which is based on the use of a Hammerstein model within a recursive control algorithm. A key contribution of the paper is the use of a novel, one-step simple root solving procedure for the Hammerstein model, this being a fundamental part of the overall tuning algorithm. A comparison is made between NLGPC and nonlinear deadbeat control (NLDBC) using the same one-step nonlinear components, in order to investigate NLGPC advantages and disadvantages.

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This paper proposes a solution to the problems associated with network latency within distributed virtual environments. It begins by discussing the advantages and disadvantages of synchronous and asynchronous distributed models, in the areas of user and object representation and user-to-user interaction. By introducing a hybrid solution, which utilises the concept of a causal surface, the advantages of both synchronous and asynchronous models are combined. Object distortion is a characteristic feature of the hybrid system, and this is proposed as a solution which facilitates dynamic real-time user collaboration. The final section covers implementation details, with reference to a prototype system available from the Internet.

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This paper examines the extent to which the valuation of partial interests in private property vehicles should be closely aligned to the valuation of the underlying assets. A sample of vehicle managers and investors replied to a questionnaire on the qualities of private property vehicles relative to direct property investment. Applying the Analytic Hierarchy Process (AHP) technique the relative importance of the various advantages and disadvantages of investment in private property vehicles relative to acquisition of the underlying assets are assessed. The results suggest that the main drivers of the growth of the this sector have been the ability for certain categories of investor to acquire interests in assets that are normally inaccessible due to the amount of specific risk. Additionally, investors have been attracted by the ability to ‘outsource’ asset management in a manner that minimises perceived agency problems. It is concluded that deviations from NAV should be expected given that investment in private property vehicles differs from investment in the underlying assets in terms of liquidity, management structures, lot size, financial structure inter alia. However, reliably appraising the pricing implications of these variations is likely to be extremely difficult due to the lack of secondary market trading and vehicle heterogeneity.

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Integrated Arable Farming Systems (IAFS), which involve a reduction in the use of off-farm inputs, are attracting considerable research interest in the UK. The objectives of these systems experiments are to compare their financial performance with that from conventional or current farming practices. To date, this comparison has taken little account of any environmental benefits (or disbenefits) of the two systems. The objective of this paper is to review the assessment methodologies available for the analysis of environmental impacts. To illustrate the results of this exercise, the methodology and environmental indicators chosen are then applied to data from one of the LINK - Integrated Farming Systems experimental sites. Data from the Pathhead site in Southern Scotland are used to evaluate the use of invertebrates and nitrate loss as environmental indicators within IAFS. The results suggest that between 1992 and 1995 the biomass of earthworms fell by 28 kg per hectare on the integrated rotation and rose by 31 kg per hectare on the conventional system. This led to environmental costs ranging between £2.24 and £13.44 per hectare for the integrated system and gains of between £2.48 and £14.88 for the conventional system. In terms of nitrate, the integrated system had an estimated loss of £72.21 per hectare in comparison to £149.40 per hectare on the conventional system. Conclusions are drawn about the advantages and disadvantages of this type of analytical framework. Keywords: Farming systems; IAFS; Environmental valuation; Economics; Earthworms; Nitrates; Soil fauna

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In this paper an attempt has been made to take a look at how the use of implant and electrode technology can now be employed to create biological brains for robots, to enable human enhancement and to diminish the effects of certain neural illnesses. In all cases the end result is to increase the range of abilities of the recipients. An indication is given of a number of areas in which such technology has already had a profound effect, a key element being the need for a clear interface linking the human brain directly with a computer. An overview of some of the latest developments in the field of Brain to Computer Interfacing is also given in order to assess advantages and disadvantages. The emphasis is clearly placed on practical studies that have been and are being undertaken and reported on, as opposed to those speculated, simulated or proposed as future projects. Related areas are discussed briefly only in the context of their contribution to the studies being undertaken. The area of focus is notably the use of invasive implant technology, where a connection is made directly with the cerebral cortex and/or nervous system. Tests and experimentation which do not involve human subjects are invariably carried out a priori to indicate the eventual possibilities before human subjects are themselves involved. Some of the more pertinent animal studies from this area are discussed including our own involving neural growth. The paper goes on to describe human experimentation, in which neural implants have linked the human nervous system bi-directionally with technology and the internet. A view is taken as to the prospects for the future for this implantable computing in terms of both therapy and enhancement.

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This paper proposes a solution to the problems associated with network latency within distributed virtual environments. It begins by discussing the advantages and disadvantages of synchronous and asynchronous distributed models, in the areas of user and object representation and user-to-user interaction. By introducing a hybrid solution, which utilises the concept of a causal surface, the advantages of both synchronous and asynchronous models are combined. Object distortion is a characteristic feature of the hybrid system, and this is proposed as a solution which facilitates dynamic real-time user collaboration. The final section covers implementation details, with reference to a prototype system available from the Internet.

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Paraplegic subjects lack trunk stability due to the loss of voluntary muscle control.This leads to a restriction of the volume of bi-manual workspace available,and hence has a detrimental impact on activities of daily living. Electrical Stimulation of paralysed muscles can be used to stabilize the trunk, but has never been applied in closed loop for this purpose. This paper describes the development of two closed loop controllers(PID and LQR),and their experimental evaluation on a human subject. Advantages and disadvantages of the two are discussed,considering a potential use of this technology during daily activities.

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We undertook a study to investigate the views of both students and staff in our department towards assessment in mathematics, as a precursor to considering increasing the diversity of assessment types. In a survey and focus group there was reasonable agreement amongst the students with regards major themes such as mode of assessment. However, this level of agreement was not seen amongst the staff, where discussions regarding diversity in mathematics assessment definitely revealed a difference of opinion. As a consequence, we feel that the greatest barriers to increasing diversity may be with staff, and so more efforts are needed to communicate to staff the advantages and disadvantages, in order to give them greater confidence in trying a range of assessment types.

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Whatever the result of Scotland’s independence referendum, careful constitutional thinking will be needed. If Scots vote Yes, Scotland will need a new constitution and the rest of the UK will have to rethink its governing structures. Even in the event of a No vote, everyone agrees that the shape of the Union will need to change over the coming years. This paper examines how such constitution-making should take place. It sets out the options, gathers evidence from around the world on how those options might work, and weighs the advantages and disadvantages of each alternative. It concludes that constitutional proposals in the UK should best be developed by a convention comprising a mixture of ordinary members of the public and politicians; these proposals should be put to a referendum. This approach, the paper argues, offers the best route to high-quality debate, stronger democratic engagement, and, ultimately, deeper legitimacy for our governing structures.

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Juvenile angiofibroma is a benign fibroangiomatous tumor of relatively rare occurrence, developing most frequently in male adolescents. It has local characteristics of aggressiveness and expansion. The treatment of choice is surgical excision. In this article, the advantages and disadvantages of the surgical technique using the Le Fort I osteotomy are described, and the literature correlated with 2 case reports.

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The purpose of this evaluation is to develop a framework that will help in planning and implementing the mobile sport exhibition, increase visitor satisfaction and aid At Bristol in building successful exhibits. The evaluation mainly focuses on visitor interaction with exhibits. It is believed that learning does occur in science centres and museums. The evaluation will therefore find out if learning occurs in the Sports exhibition and if so, the nature of the learning outcomes. The evaluation also discusses advantages and disadvantages of travelling exhibitions and identifies the characteristics of good exhibits that form the basis of the framework.From the results, an indication is that children make the larger proportion of visitors to Sportastic. Their age ranges, under 10 and 10 to 15 years constituted 21% and 30% respectively. The three most enjoyed exhibits are the Sprint Challenge (running), BATAK (test your reaction and Hot Shots (football). Visitors say these exhibits are enjoyed because they are fun, competitive, entertaining, interactive and hands-on. Skateboard Challenge and Skeleton Bob are among the exhibits least enjoyed since they are reported to be boring and uncomfortable to use. The learning outcomes from the exhibits are; increased knowledge about balancing, reaction, pulse and strength.

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Syftet med denna uppsats är att ta reda på hur lokala kommunikationskonsulter i Falun/Borlänge-regionen ser på opinionsbildning via professionella konsulter. De centrala begrepp som avhandlas är PR, opinionsbildning och lobbying.Den teoretiska ram som omger undersökningen består av de teoribyggen som skapats av Jürgen Habermas, James E. Grunig och Larsåke Larsson. Habermas ställer sig tveksam till den demokratiska nyttan av professionell opinionsbildning, Grunig är mer positiv och Larsson ser både för- och nackdelar med PR-verksamheten. Larssons undersökning av opinionskonsulter från 2005 refereras också.Undersökningen bygger på intervjuer med ett antal kommunikationskonsulter verksamma i Falun och Borlänge. Den lokala marknaden för opinionsbildande uppdrag diskuteras, men också huruvida politiska uppdrag förser byråerna med politisk färg. Huruvida medarbetarnas engagemang är viktigt och hur hög statusen på opinionsbildande uppdrag är ventileras, samt vilka arbetsmetoder som används. Intervjuerna behandlar också förekomsten av lobbying på lokal nivå. Till slut redogör de intervjuade för sin syn på hur opinionsbildning, PR och lobbying via konsulter påverkar demokratin.Under slutsatser diskuteras resultatet i relation till den teoretiska ramen. Att PR- och reklambranscherna alltmer växer samman och att opinionsbildning är ett vanligt inslag i många projekt är ett faktum som också skymtat fram i den teoretiska ramen. Men reklam- och PR-metoder integreras också i politiken, på gott och ont. Följaktligen växer den gråzon som finns mellan de olika typerna av kommunikation och mellan opinionsbildande och icke-opinionsbildande uppdrag. Det försvårar gränsdragning och tydlighet, men skapar nya kreativa möjligheter.Att den ökade användningen av kommunikationskonsulter kanske kan bidra till en orättvis fördel för resursstarka organisationer diskuteras. Ny teknik, t.ex. Internet, kan dock eventuellt vara den motvikt som gör det möjligt även för resurssvaga grupper att höras i det offentliga samtalet. Kommunikation som maktfaktor tas även upp utifrån termer som lobbying och medias dagordningsfunktion.Några aspekter av den outnyttjade potential som PR har ventileras också. PR som metod är en outnyttjad resurs på det lokala planet, något som kan bero både på okunskap hos de lokala kunderna och ett traditionellt arbetssätt hos byråerna. Utifrån intervjusvaren framkommer att både byråerna, deras kunder och media på landsorten skulle gynnas av ett större samarbete.Resultaten av intervjuerna stöder mycket i den teoretiska ramen, medan somligt förkastas. Som sammanfattning kan sägas att opinionsbildning via konsulter kan användas för både gott och ont. Vilket som blir resultatet handlar som oftast om etik, ansvar, öppenhet och professionalitet.ABSTRACTThe primary target for this report is to find out how communication consultants in the region of Falun and Borlänge views the practice of establishing public opinions by using professional public relations consultants. The concepts in focus are PR, the moulding of public opinion and lobbying.The theoretical framework surrounding this report is the writings by Jürgen Habermas, James E. Grunig and Larsåke Larsson. Habermas has doubts as to the democratic use of professional consultants working with public opinions, Grunig has a somewhat more positive approach and Larsson sees both advantages and disadvantages in a democratic sense with the PR industry. Larssons research concerning consultants working with the moulding of public opinions from 2005 is also reviewed. The research is carried out by interviewing some communication consultants working in the Falun /Borlänge- area. The local market for commissions concerning public opinions is discussed, but also if and how political commissions are forcing a political stamp upon the firms engaging in such commissions. The importance of personal commitment in the consultants and the level of prominence commissions concerning public opinion has in the business is discussed, but also which methods is used and preferred. The interviews also deal with the practice of lobbying in the local arena. Finally the participants state their views on how the moulding of public opinion, PR and lobbying effects the democracy. Conclusively, the result is put in relation to the theories earlier mentioned. The public relations market is merging with the advertising business, that is a fact, and establishing public opinion is a common element in a lot of projects. But methods used for advertising and PR are also integrated in the political sphere, for good and bad. That has made the distinction between different kinds of communication harder, thereby enhancing the difficulties of establishing boundaries and achieving clarity. Yet at the same time it facilitates new creative opportunities.The growing use of communication consultants may contribute to unfair advantages for organisations with large economic resources. New technical development though, such as the Internet for example, may prove to simplify communication for groups with lesser economic power. Communication as an aspect of power is being discussed in terms of lobbying and the agenda setting power of media.Some aspects of the unused potential that lies within PR are also in focus in this report. PR as a method is an unused resource in the local market, which can be due to the local clients lack of knowledge but also to the traditional work carried out by the communication firms. The findings of the interviews show that both communication firms, their clients and the local media would benefit from greater cooperation.The theoretical base in this work is mostly supported by the interviews, though a few of the findings does not agree. The moulding of public opinions by professional consultants can be used for both good and bad. What the result will be is, not surprisingly, a question of ethics, responsibility, openness and professionalism.

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This report presents an algorithm for locating the cut points for and separatingvertically attached traffic signs in Sweden. This algorithm provides severaladvanced digital image processing features: binary image which representsvisual object and its complex rectangle background with number one and zerorespectively, improved cross correlation which shows the similarity of 2Dobjects and filters traffic sign candidates, simplified shape decompositionwhich smoothes contour of visual object iteratively in order to reduce whitenoises, flipping point detection which locates black noises candidates, chasmfilling algorithm which eliminates black noises, determines the final cut pointsand separates originally attached traffic signs into individual ones. At each step,the mediate results as well as the efficiency in practice would be presented toshow the advantages and disadvantages of the developed algorithm. Thisreport concentrates on contour-based recognition of Swedish traffic signs. Thegeneral shapes cover upward triangle, downward triangle, circle, rectangle andoctagon. At last, a demonstration program would be presented to show howthe algorithm works in real-time environment.

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This report presents a new way of control engineering. Dc motor speed controlled by three controllers PID, pole placement and Fuzzy controller and discusses the advantages and disadvantages of each controller for different conditions under loaded and unloaded scenarios using software Matlab. The brushless series wound Dc motor is very popular in industrial application and control systems because of the high torque density, high efficiency and small size. First suitable equations are developed for DC motor. PID controller is developed and tuned in order to get faster step response. The simulation results of PID controller provide very good results and the controller is further tuned in order to decrease its overshoot error which is common in PID controllers. Further it is purposed that in industrial environment these controllers are better than others controllers as PID controllers are easy to tuned and cheap. Pole placement controller is the best example of control engineering. An addition of integrator reduced the noise disturbances in pole placement controller and this makes it a good choice for industrial applications. The fuzzy controller is introduce with a DC chopper to make the DC motor speed control smooth and almost no steady state error is observed. Another advantage is achieved in fuzzy controller that the simulations of three different controllers are compared and concluded from the results that Fuzzy controller outperforms to PID controller in terms of steady state error and smooth step response. While Pole placement controller have no comparison in terms of controls because designer can change the step response according to nature of control systems, so this controller provide wide range of control over a system. Poles location change the step response in a sense that if poles are near to origin then step response of motor is fast. Finally a GUI of these three controllers are developed which allow the user to select any controller and change its parameters according to the situation.

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Syftet med denna studie är att få kunskap om lärares syn på matematikläxor i grundskolans tidigare år. Förhoppningen var att få förståelse för lärares syfte med matematikläxor och vilka förmågor eleverna förväntas utveckla med matematikläxors hjälp samt att jämföra vilka för- och nackdelar matematikläxan har. För att undersöka detta har sju intervjuer gjorts med lärare från olika skolor och olika årskurser från 1-6. Samtliga lärare som intervjuats undervisar i matematik. Lärares erfarenheter av läxornas betydelse för matematikundervisningen är ett viktigt område att få kunskap om. De lärare som deltog i intervjuerna uttryckte olika synpunkter på matematikläxan. Något lärarna var överens om var att läxa är en skoluppgift som eleven tar med hem efter skolans slut och arbetar med hemma. Lärarna uttryckte samstämmigt att eleverna inte utvecklar några förmågor med matematikläxans hjälp utan förmågorna utvecklar eleverna i skolan med hjälp av lärarna. Det framgick att samtliga lärare upplevde att matematikläxan var tidskrävande och för att matematikläxan ska nå syftet på bästa möjliga sätt behövs mer tid. Att läxan kopplas till undervisning och uppföljning är centralt för att syftet med matematikläxan ska uppnås enligt de intervjuade lärarna. Av resultaten framgår att några lärare är negativt inställda till matematikläxor för att uppföljning och koppling till undervisningen inte finns med och därför förlorar matematikläxan sitt syfte. Föräldrarnas förutsättningar är väldigt olika som exempelvis att de har svårigheter med det svenska språket eller inte är engagerade i barnets skolgång. Andra lärare är positivt inställda till matematikläxor för att färdighetsträningen och repetitionen är viktig och tiden som behövs för det inte räcker till i skolan.