Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 9007 result(s) returned

2.3 Attenuation

Activity 2

At approximately what wavelength is the attenuation of optical fibre lowest? What, approximately, is the attenuation at that wavelength? What other wavelengths are used and why?


Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Introduction

This unit is from our archive and it is an adapted extract from Digital Communications (T305) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer in this curriculum area.

By using optical fibre, very high data rates (gigabits per second and higher) can be transmitted over long d
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Module team

Rosalind Armson, author

Joyce Fortune, case study author

Ray Ison, author

Martin Reynolds, course chair

Laurence Newman, course manager

Mike Aiken, critical reader

Mandy Anton, graphic designer

Simon Bell, critical reader

Victor Bignell, critical reader

Chris Blackmore, critical reader

Jake Chapman, critical reader

Tony Duggan, project controller (Technology)

Pip Harris, compositor

Mike Haynes, critical
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

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:


Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

6.4 Choosing to distinguish between complex situations and complex systems

Within some of the lineages of systems thinking and practice (Figure 7), the idea that system complexity is a property of what is observed about some ‘real-world’ system, is known as classical or type 1 complexity. Exploring type 1 complexity, Russell Ackoff (1981, pp.26–33) claimed for a set
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

5.7 Being ethical

As outlined in Table 2, ethics within systemic practice are perceived as operating on multiple levels. Like the systems concept of hierarchy, what we perceive to be good at one level might be bad at another. Because an epistemological position must be chosen, rather than taken as a given, the choi
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

2.4 Review

In working through this section, you have identified some of your initial expectations and I have explained some of what I think you will discover as you work through the unit. It would be appropriate at this point to look at some of the questions I asked you about your expectations again and note ways your expectations have changed.

Spend a total of around 30 minutes on the next three activities.

Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Introduction

When you meet with a situation you experience as complex you need to think about yourself in relation to the process of formulating a system of interest. Only with this awareness, can you increase your range of purposeful actions in the situation which are ethically defensible. To do so is the hallmark of systemic thinking and practice compared to systematic thinking and practice. The metaphor of the systems practitioner as a juggler of four balls is introduced as a device to explore skill de
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

5.6 Identification

We end Act 1 with a clear understanding that it is actually too late for Ned to pull out, even if he wanted to: the weapon has been designed. If he were concerned about the military technology, he should really have worried about that before he took on the job. But he does not, at the end of Act 1, want to pull out. He clearly wants to see the project through. Materialising this idea is what he lives for, and he says this is at the cutting edge, this is where technology is. These ideas are go
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

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
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Introduction

Ethics is an established area of academic interest, but it is only fairly recently that the relevance of ethics to Information and Computer Sciences (ICS) started to emerge clearly outside philosophical studies. Professional bodies in Engineering and ICS have begun to require, as a condition for accreditation, the study of ethics-related topics, and, partially in response to these requirements, new pedagogies for teaching and learning these topics are gradually emerging.

This unit expl
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

6.10 Action plans

  • 22. Does the action plan make the proposal concrete in terms of realistic time scales and budgets and identification of relevant milestones?

A reasonably detailed action plan has four distinct functions in your proposal:


    Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

6.6 Risks

  • 15. What are the risks associated with the change that might mean the intended benefits cannot be realised?

  • 16. How can these risks be mitigated or eliminated?

No plan for the future ever comes with a 100 per cen
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

6.5 Costs

  • 11. What are the financial costs involved (capital and recurring)?

  • 12. What additional non-financial resources will be needed?

  • 13. When are the all the various financial and non-financial resources needed?


  • Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

3.4 Managing across interfaces

Increasingly, operations management is seen as an interface discipline (Voss, 1995). Managing across interfaces, both internal and external to the organisation, is a particular challenge for managers and this is discussed further in this section.

Information and communications technology is an important means of linking across the various interfaces. Author(s): The Open University

3.1 Introduction

The purpose of this section is to address the following interlinked questions:

  • Just what do we mean by business operations?

  • Why is it so important?

  • Where does technology fit in?

I begin answering these questions with a discussion of how best to represent operations activities, making the case for the process view of the organisation. This leads to discussion of the nature and scope of the operations managem
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

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
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

8.2 Wet etches: acids and bases

The simplest etches use a liquid solvent that converts the material into a soluble compound or a gas. Unfortunately, most materials used in micro-devices have few soluble compounds, so some very aggressive chemicals are needed to attack them. Here is a list of some of the most commonly used ones:

  • Hydrofluoric acid (chemical formula HF) is used to convert silicon dioxide into water-soluble H2SiF6 (plus some hydrogen and water). It
    Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

7.4 Depositing compounds

As well as conducting metal layers, device fabrication requires dielectric, insulating materials and these are mostly chemical compounds rather than simple elements or alloys. By far the most widely used of these is silicon oxide (either as a glass or as crystalline quartz), but other oxides and nitrides are also common, plus polymers and a selection of more exotic materials.

Such compounds generally have very high melting points, or decompose under heating, so cannot be deposited by ev
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

7.3.2 Evaporation

The simplest vacuum deposition technique is to heat an ingot of metal in a crucible under vacuum, releasing metal vapour that coats everything in its path. This can be done either under high vacuum (< 0.1 mbar), in which case only surfaces in a line of sight from the source will be coated, or in a low-pressure atmosphere, when the vapour is scattered by gas atoms and can go around corners, making batch processing of multiple wafers possible.

This rather simple technique is fast and chea
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451