4.4 The use of systems engineering in organisations: different organisational arrangements Hall identified three different organisational arrangements that might provide a framework within which systems engineering work could take place within the organisation. The first of these, which he termed the departmental form and regarded as the lowest level of arrangement, was essentially a temporary team of specialists brought together, under the management of a team leader, to undertake a specific project. The team consisted of members of each of the specialist development departments a
Stage 2: The situation analysed The first step is to develop a picture (called in soft systems terminology a rich picture) that encapsulates all the elements that people think are involved in the problem. Once the rich picture has been drawn, the analyst will attempt to extract ‘issues’ and key tasks. Issues are areas of contention within the problem situation. Key tasks are the essential jobs that must be undertaken within the problem situation. 1.9 Increasing complication, complexity and risk: summary The three levels of change problem, simplicity, complication and complexity, can be associated with craft, engineering and systems engineering knowledge. The three categories of change problem represent different levels of uncertainty of what needs to be done and how to do it. The greater uncertainty brings increased risk. Although we tend to be risk averse we will take on greater risk if the returns are commensurate with doing so. Human experience can be divided into three worlds. The 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 source for permission to reproduce material within this unit: 4.5.2 10 Gigabit Ethernet The standard for 10 Gigabit Ethernet (IEEE 802.3ae, lOGbE) was approved in July 2002. The main use of lOGbE, initially at least, is for backbone networks which interconnect 10, 100 or 1000 Mbit/s Ethernet hubs. These hubs might be widely separated geographically, so the standard includes physical layer specifications specifically for WAN (wide area network) applications as well as LAN applications. The WAN specification is for operation at slightly under 10 Gbit/s, 9.95328 Gbit/s, so as to be 4.5 Fibre in LANs Fibre has been slower to be exploited in LANs than in the core transmission network, for similar reasons to the delay in the use of fibre in the access network, but as the data rate demanded of LANs has increased, the case for using fibre has strengthened. Although Ethernet specifications (IEEE 802.3 series) have contained standards for the use of fibre backbones for some time, it was with the development of Gigabit Ethernet and 10 Gigabit Ethernet (10 GbE) standards that fibre became t 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. 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 sources for permission to reproduce material within this unit: References 6.5 Appreciating some implications for practice I think for most people, the National Health Service would be experienced as a complex situation. If so this would be a good example of perceived complexity. Remember though, if you engaged with it as if it were a difficulty you would not describe the situation as one of perceived complexity. I could not call it a complex system unless I had tried to make sense of it using systems thinking and found, or formulated, a system of interest within it. This means I would have to have a stake in the 4.6 What matters? When the laptop is confirmed to be uncompromised, it is interesting that none of the characters cheers, although they all seem to be relieved. In other words, when the statement comes up, ‘laptop is uncompromised’, people seem to think that is ‘good’, the outcome is fine. They seem to have forgotten that the technician is probably dead at the time. So, in their deliberations, a person's life is forgotten. I am sure that, if they were reminded of it, they would, of course, say that thi References 6.9 Supporting evidence 20. Are all the assertions concerning costs, benefits and risks backed up by relevant supporting evidence? 21. If not, how can this evidence be collected and presented? As was mentioned in Author(s): 6.7 Cost-benefit analysis 17. Does the case clearly and unequivocally demonstrate that benefits outweigh costs? In some contexts ‘cost-benefit analysis’ implies some specific formal method of assessing costs in relation to expected benefits. For example, i 3.2 Business operations: function or process? Traditionally, an enterprise's activities are organised according to a structure based on the well-known business functions: marketing, purchasing, finance, human resources, research and development (R&D), operations, and so on. The exact function title varies from organisation to organisation, but each function has its own more or less well-defined sphere of activity. It carries out its various tasks and passes on information or artefacts to other functions for them to work on. For example, 8.3.6 Deep silicon etching MEMS structures often require etching to a much greater depth than is needed for microelectronics. A rate of 1–2 μm min−1 may be quite sufficient for making transistors less than 1 mm deep, but to etch through 600 mm of silicon to form an accelerometer would take all day. The advent of MEMS and wafer-level packaging applications, therefore, brought a need for yet faster anisotropic etches, requiring advances both in the process and in the etching equipment. Capacitive co 7.4.3 Chemical vapour deposition (CVD) If step coverage or equipment cost is more critical than purity, then PVD is supplanted by CVD. There are many variants on the chemical vapour deposition technique, but the concept is simple: gases adsorb onto the wafer surface where a chemical reaction forms a solid product. Any other products are gases, or at least volatile liquids, and are pumped away. There is one obvious restriction: the wafer surface must be the only place where the reaction can occur. If it is not, particle 7.3.3 Plasmas More control can be achieved in vapour deposition if a plasma is generated. A plasma is simply a gas where a proportion of the molecules have been ionised. The ions remain in an uneasy equilibrium with the electrons they have released, prevented from recombining only because the electrons are hot and fast-moving, and so are difficult to trap. Plasmas are widely used in materials processing, with pressure ranging from 10−3 mbar to 1 mbar and typically up to 1% of the molecul 7.3 Depositing metals and alloys Metal layers are used extensively in device fabrication: to carry current for both power and signals, to apply the voltages that control transistors and generate forces for MEMS, as mirrors and optical coatings, and in magnetic devices for recording media. Different applications might require a continuous film, a long track, multiple thin layers or a plug filling a ‘via hole’ through to a buried layer. The electrical properties resulting from micro structure and composition must be contro
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