3.5 Distinctions about systems practice A tension has existed throughout the history of Western thought around whether to focus on parts or the whole. The practice that springs from this history carries the same tension. This tension has been particularly visible within science and philosophy for a long time and it gives rise to different approaches. I will be addressing these tensions in Author(s):
Part 2: 1 Introduction I have a number of purposes in mind as I write Part 2. You can read these in conjunction with Figure 4. 14 Part 2: 5 Self-assessment questions What are the four main factors that motivate individuals to invent? Individuals are motivated to invent by one or more factors: 11.3 Step 2 – exploration This is the period when, following the identification of the problem, attempts are made to understand it better and to make a stab at designing a solution. This might be a short process or it could take years and involve a detailed search for information, experimenting with different designs, even redefining the problem as a result of this activity. Alexander Graham Bell adopted a problem-focused strategy when exploring the problem of designing a working telephone. This strategy is one 10.6 What drives invention in organisations? Much invention and nearly all innovation nowadays take place inside organisations – from small start-up companies to well-established multinationals. This is mainly because increasingly invention and innovation require access to technology and resources beyond the scope of most individuals. But it is also because competitiveness and survival depend on the continual improvement of a company's products and processes. This provides a strong incentive for companies to invest in both the increme 10.5 Desire to help others This is a less common motivation but it shows not everyone is driven by money. In 1991 the inventor Trevor Baylis saw a BBC documentary about the spread of HIV/AIDS in Africa. What was needed was a way of broadcasting the safe-sex message to people in areas without electricity and where batteries for a radio could cost a month's wages. Solar power wouldn't necessarily help as most people who could get to a radio listened in the evening after work. While absorbing this information he ima Introduction Pictures speak louder than words. But how can you use diagrams to help you? This unit looks at how diagrams can be used to represent information and ideas about complex situations. You will learn how to read, draw and present diagrams to help illustrate how ideas or processes are connected.
This unit is from our archive and is an adapted extract from Systems thinking and practice: diagramming (T552) which is no longer taught by The Open University. If you want to study formally with us 12.1.1 Survey questionnaires Questionnaires are lists of questions that enable information to be gathered efficiently from a relatively large number of respondents. Most questionnaires require a fixed type of response, such as a choice between available answers, or along a scale of response. For example, a product design questionnaire might suggest, ‘I found the product easy to use’ and provide a five-point scale of response from ‘agree strongly’ to ‘disagree strongly’. Or a question might be, ‘how often do 10 User research techniques: observing users This section introduces an alternative to basing user research on yourself. This is observation of experienced and inexperienced users either in experimental or natural situations. One way around the difficulties of basing research on oneself is to observe other people acting as users and to choose naive or different kinds of experienced users, depending on what information you want to gather. Begin by identifying those experienced users who will be able to provide you with releva 9.1.1 Point of view Decide first of all which user's point of view you are taking: consumer, operator, maintenance person, and so on. You may want to make several trips, from different user perspectives, or try special user perspectives, such as that of a disabled person. It is usually easiest to take a consumer's trip because you may need special permission, access, and perhaps skills, before you can take any other. 8.1.1 Visibility Recall that a key usability design feature identified by Donald Norman – from his analysis of using everyday objects such as doors – was visibility. An everyday object such as a door, or a control such as a button on a product should appear to be obvious about how it is used, and indeed it should perform that obvious function. For example, is it obvious how you insert a disc into a player? Is it obvious how you switch the machine on, adjust volume, and so on? 8.1 Making usable products This section reveals that many modern products need to usable by our minds as much as our bodies. Products need to be understandable, and present information and feedback in meaningful ways. A lot of ergonomics research is aimed at establishing guidelines, standards or rules that can be applied by designers in a variety of situations. Where this applies to the physical use of products, much of it is based on standard body measurements. These body measurements are known as anthropomet 4 Who are the users? This section reveals that ‘users’ can include a wide variety of people – not just the final purchasers or consumers of a product. The section also makes the case for strong user representation in the design process. Of course, it is not only me who uses the various products in my home; other people use them as well, both members of the family and visitors. Sometimes the range of users of a product, and their different needs, can be diverse. And in addition to the obvious or intend 5.7.1 Mixed oxidant gases system This is a relatively new system of disinfection. It involves electrolysis of high-purity NaCl brine to produce a mixture of chlorine dioxide, ozone and hypochlorite. This mixture is separated within the electrochemical cell by a membrane, or by exploiting density difference, and is then metered into the water requiring disinfection. The mixed oxidant gases are generated on demand and this is a great safety advantage, compared with having storage tanks of chlorine on site. The source for the d 2.11 Storage In a given fixed space at any phase of the hydrological cycle, there is an inflow and an outflow of water, the rates of which vary with time. The total cumulative difference between inflow and outflow is the storage. So within that space there is a body of water whose mass is not directly controlled by instantaneous values of inflow and outflow. For example, in river flow the movement of the whole body of water in the channel is generally downstream, yet a given reach contains a volume whose 2.7 Infiltration Entry of precipitation through the soil surface and on downwards, by gravity, is known as infiltration. The rate at which this process can take place is governed by the permeability (a measure of the ease with which water can flow through the subsurface layer) and by the existing degree of saturation of the soil. Infiltration can be impeded by outcropping impermeable rocks or by paved areas, and also by the presence of finegrained soils with a low permeability (such as clay). At certain times 2.6 Precipitation
Precipitation
is defined as the depth of rainfall, or the water equivalent of snow, sleet and hail falling during a given measurement period. It may be in the form of rain, snow, sleet or hail, or in minor forms such as dew and hoar frost, but existing theories do not yet satisfactorily account for all the observed characteristics. In tropical climates, precipitation occurs as a result of the gradual coalescence of the tiny condensed droplets as they collide within the cloud 2.3 Transpiration If there were no vegetation, the rate of evaporation from land surfaces after rain would diminish rapidly to a very low value. Plants increase this rate by transpiration. In this process, water is transferred from the soil through the roots to the leaves by osmosis and capillary action. Water evaporates from the surface of the leaves and the resulting vapour diffuses into the atmosphere. For hydrological measurements, this phenomenon is frequently lumped with evaporation because the two proce 1 Some facts about water
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