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diff --git a/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt b/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt deleted file mode 100644 index 2d0cdf9..0000000 --- a/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt +++ /dev/null @@ -1,191 +0,0 @@ -1 -00:00:00,120 --> 00:00:02,600 -The next model that we will discuss is the spiral - -2 -00:00:02,600 --> 00:00:05,630 -model, which was first described by Barry Boehm, which is - -3 -00:00:05,630 --> 00:00:08,010 -the professor that we interviewed at the beginning of this - -4 -00:00:08,010 --> 00:00:12,240 -lesson. In his paper from 1986 that was entitled A Spiral - -5 -00:00:12,240 --> 00:00:15,730 -Model of Software Development and Enhancement. And one of the - -6 -00:00:15,730 --> 00:00:18,520 -main characteristics of that paper is that it was describing the - -7 -00:00:18,520 --> 00:00:21,670 -spiral model using a diagram, which is the one that - -8 -00:00:21,670 --> 00:00:25,130 -I'm showing you here, and this diagram has become very very - -9 -00:00:25,130 --> 00:00:27,950 -popular, and you probably saw it either in this - -10 -00:00:27,950 --> 00:00:30,400 -form or one of the many variations of the - -11 -00:00:30,400 --> 00:00:32,680 -diagram. So I'm not going to discuss all of - -12 -00:00:32,680 --> 00:00:34,770 -the details of the spiral model, but I just want to - -13 -00:00:34,770 --> 00:00:37,510 -give you an idea of its main characteristics. The - -14 -00:00:37,510 --> 00:00:41,580 -spiral model is an incremental risk-oriented lifecycle model that has - -15 -00:00:41,580 --> 00:00:46,330 -four main phases listed here: determine objectives, identify and - -16 -00:00:46,330 --> 00:00:51,180 -resolve risks, development and tests, and plan the next iteration. - -17 -00:00:51,180 --> 00:00:53,690 -A software project will go through these four phases in - -18 -00:00:53,690 --> 00:00:57,020 -an iterative way. In the first phase, the requirements will - -19 -00:00:57,020 --> 00:00:59,470 -be gathered. In the second phase, the risks and the - -20 -00:00:59,470 --> 00:01:04,010 -alternate solutions will be identified, and a prototype will be produced. - -21 -00:01:04,010 --> 00:01:06,190 -Software and tests for the software are produced in the - -22 -00:01:06,190 --> 00:01:09,210 -development and test phase, which is the third step of the - -23 -00:01:09,210 --> 00:01:12,830 -process. Finally, in the fourth phase, the output of the - -24 -00:01:12,830 --> 00:01:16,880 -project, so far, is evaluated, and the next iteration is planned. - -25 -00:01:16,880 --> 00:01:19,960 -So basically, what the spiral process prescribes is a - -26 -00:01:19,960 --> 00:01:23,262 -way of developing software by going through these phases in - -27 -00:01:23,262 --> 00:01:26,020 -an iterative way, in which we learn more and more - -28 -00:01:26,020 --> 00:01:29,420 -of the software, we identify more and more, and account - -29 -00:01:29,420 --> 00:01:32,250 -for, more and more risks and we go more - -30 -00:01:32,250 --> 00:01:36,000 -and more towards our final solution, our final release. There - -31 -00:01:36,000 --> 00:01:38,930 -are several advantages of using a spiral model. The first - -32 -00:01:38,930 --> 00:01:41,930 -one is that the extensive risk analysis does reduce the - -33 -00:01:41,930 --> 00:01:44,140 -chances of the project to fail. So there is a - -34 -00:01:44,140 --> 00:01:48,300 -risk reduction advantage. The second advantage is that functionality can be - -35 -00:01:48,300 --> 00:01:51,190 -added at a later phase because of the iterative nature of - -36 -00:01:51,190 --> 00:01:55,175 -the process. And finally, software is produced early in the software - -37 -00:01:55,175 --> 00:01:58,260 -lifecycle. So, at any iteration, we have something to show - -38 -00:01:58,260 --> 00:02:01,300 -for our development. We don't wait until the end before producing - -39 -00:02:01,300 --> 00:02:03,790 -something. And then of course there's also the advantage that we - -40 -00:02:03,790 --> 00:02:07,190 -can get early feedback from the customer about what we produced. - -41 -00:02:07,190 --> 00:02:09,000 -The main disadvantages on the other hand of - -42 -00:02:09,000 --> 00:02:11,870 -the spiral model, are that the risk analysis requires - -43 -00:02:11,870 --> 00:02:16,560 -a highly specific expertise. And unfortunately, the whole success - -44 -00:02:16,560 --> 00:02:19,260 -of the process is highly dependent on risk analysis. - -45 -00:02:19,260 --> 00:02:21,580 -So risk analysis has to be done right. - -46 -00:02:21,580 --> 00:02:24,510 -And finally the spiral model is way more complex - -47 -00:02:24,510 --> 00:02:27,180 -than other models, like for example, the water fall - -48 -00:02:27,180 --> 00:02:29,760 -model. And therefore it can be costly to implement. |