4.3 Optical networking DWDM improves the utilisation of optical fibre for point-to-point links, but a further step in exploiting the potential of optical fibre comes from optical networking in which routeing or switching is done optically. Optical networking is in its infancy, but the concept of the optical layer based upon wavelength channels is emerging. The optical layer effectively sits below the SDH layer in the network, and provides wavelength channels from one location to another. An analogy can
2.4.1 Multimode distortion With multimode fibre, the main cause of pulses spreading is the multiple paths that signals can traverse as they travel along the fibre. This phenomenon of multimode distortion is illustrated in Figure 5. 4.2 The good, the bad and the loyal Read the script of the play Last Call by clicking on the link below. Jot down some ideas on the main issues, you feel, the play suggests. 1.5 Reasons One thing that reasons do is to provide explanations as to why someone acted in a certain way. If someone gives ‘wrong’ reasons, then doubts may arise about the quality of any deliberations undertaken by that person. So, ‘wrong’ reasons raise doubts concerning his or her future actions and the products of those actions. Quite a lot hinges on people's experiences of other people's judgements, so if someone's judgements seem to have given satisfactory results in the past, then we're inc 1.4 What is ethics? I'd like to introduce an idea of ethics based on the work of G. E. Moore, a Cambridge Don who died fifty years ago. Bearing in mind that concerns with ethics date back at least to the Ancient Greeks, you might not be surprised that I bring in some ideas from Moore's Principia Ethica, a text written over 100 years ago but articulated in a particularly clear and plain-speaking style. Moore's take on things is that when ‘good’ and ‘bad’ are involved, then we're in the realm of eth 1.2 Ethical examples But is this a tenable position? In other words, is it only the people who use the technologies who carry the ethical burden? Conversely, is ethics of any interest to engineers, programmers and scientists? What, in the first place, constitutes an ethical issue? To begin examining these questions, let's look at some examples. 6.8 Anticipating the arguments 18. Have the objectives and perspectives of all the key stakeholders concerned with the decision been taken account of in the previous assessment of costs, benefits and risks? 19. What are the reasons that this proposal is preferred over other op 4.1 Background to Vue This section discusses one of four video case studies used in the T883 course to illustrate some basic concepts of operations management covered by the course. Vue Entertainment is a relatively young organisation, formed in 2003 with the acquisition of 36 cinemas from the Warner Village chain. At the time of writing (October 2007) it currently operates 579 screens and 130,585 seats over 59 cinemas. It sees its approach as firmly based upon its desire to consistently provide ‘the best 6.2 Natural frequency of free oscillations Most of us have a fairly accurate understanding of what is meant by resonance – it's what causes a bell to continue to make a sound long after it has been struck. Yet this is just one example of resonance, a phenomenon that occurs in nature in a surprisingly large number of places. It is all to do with the reversible transfer of energy from one form to another in a system. The common feature associated with mechanical systems that are able to store energy by oscillating is that they h 3.8 Review In the first three sections, we have looked at devices whose usefulness is dependent on their form. In the case of the Pirani sensor, it was the dimensions of the microbridge that affected its sensitivity; in the AFM probe, its ability to resolve features on a surface is determined mostly by the form of the last few nanometres of its very tip. With devices the emphasis is not so much on the form of the structure as on how to make it move in the right way and, just as importantly, how to detec 6 A problem with sensors The problem we will look at in this section concerns the analysis of the design of a component used in cars that are fitted with airbags. The airbag has to be inflated rapidly when an electronic circuit in the system decides that a serious collision is taking place. The crucial component in the electronics is the accelerometer, which therefore has to be extremely reliable. Motor manufacturers have turned to a technology called MEMS (micro-electromechanical systems) for these accelerometers, b 1.2 Innovation by context The word ‘innovate’ simply means ‘make new’. We have chosen in this unit to narrow the meaning of this term to be more or less synonymous with ‘invention’. I would argue that innovation by context is as much a process as a result. By that, I'm using the term to mean something more like ‘creativity’; and it's creativity that lies at the heart of all engineering. More than anything else in our professional lives, we engineers are excited by the prospect of being responsible for 1.1 Solving problems It could be said that our species is defined by its irresistible urge to solve problems – it's what makes us human. Strange, then, that the word ‘problem’ has such negative overtones. I think that the root of this paradox is that the word is used both when we identify a need – the first link in the problem-solving chain – and when we undertake the process of meeting that need. It is the identification of the need and the realisation that it is real and must be met that creates the a Learning outcomes After studying this unit you should be able to:
View solutions as belonging to particular categories, broadly classified as:
innovation by context innovation by practice routine.
See how external factors affect engineering projects, and appreciate the range of engineering involved in meeting the basic needs of our society.
Recognise and apply a range of problem-solving techniques fr Acknowledgements Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence Grateful acknowledgement is made to the following for permission to reproduce material: 6.2 Forth Bridge When the Forth was eventually bridged in 1890 it marked a new dimension in bridge construction. The main crossing is 5330 feet long and has a headroom above high water of fully 157 feet. It consists of three huge double cantilevers fabricated from steel with a maximum height above high water of 361 feet. The bridge contains 58 000 tons of steel, of which 4200 tons are just rivets. The steelwork has an external area of 145 acres and it is a full-time job for a gang of 29 painters to protect th 4.7 Photographs showing the detail: damage to pier 1 The final example of a partly collapsed pier is pier 1, photographed from the base of pier 28 and shown in Figure 32. Fracture damage to the flange at the top of the second tier is visible on the east-most column (top right); a large chunk of metal has broken off. The southern column (right of centre) exhibits 4.1 Condition of the bridge: an overview An investigation was put into motion by the Board of Trade (BoT) as soon as news of the catastrophe reached London. Three commissioners were appointed to consider the evidence. They proceeded at their task with haste, knowing the country looked to them for an explanation of the accident. Fifty photographs were taken of the remains of the bridge about a week after the collapse at the request of the BoT enquiry team. The photographs are vital evidence of the way the bridge piers fai 3.5 Sunday 28 December 1879 The morning of Sunday 28 December 1879 was quiet. When Captain Wright took his ferry boat, the Dundee, across the firth at 1.15 pm, he noted that the weather was good and the water was calm. The 4.15 pm crossing was just as uneventful, but the captain noted that the wind had freshened. By 5.15 pm a gale was moving in from the west and the river, in the words of the captain ‘was getting up very fast’. The local shuttle train left Newport at 5.50 pm and arrived at Dundee statio 3.4 Building the bridge The contract for the bridge was won by the firm of Charles de Bergue, and a contract signed on 8 May 1871, whereby the contractor undertook to have the bridge ready for traffic in three years at a price of £217 000. In the event the bridge was opened on 31 May 1878, by which time it had cost £300 000. Work started on the south bank of the Tay, with piers laid on to solid rock foundations. As the piers advanced into the estuary, foundations needed to be sunk onto the river bed, and cai
Activity 15
Example 1: Th
