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1 jontas 1.1 %Assignment is conducted in pairs. Max. 8 pages.
2     \documentclass[12pt, a4paper]{article}
3     \usepackage[latin1]{inputenc}
4    
5     \begin{document}
6     \pagenumbering{roman}
7     \thispagestyle{empty}
8     \begin{centering}
9     Assignment 1 - PAC003: Software Metrics, 5p\\
10     Jonas Petersson \& Mathias Börjeson\\
11     \emph{jopd01@student.bth.se \& tb00mbo@student.bth.se}\\
12     \end{centering}
13     \tableofcontents
14     \newpage
15     \pagenumbering{arabic}
16     \section{Internal product attributes}
17     \subsection{Explain how the three aspects of the software size (Length,
18     Functionality and Complexity) are supplementing each other to describe
19     the notion of software size.}
20     %length = is a physical size of the product
21     %functionality = counts the functions supplied by the product
22     %complexity = measures the complexity od underlying problem, or a solution
23     %utan att ha en aning om hur notationen ser ut drar jag till med följande
24     These three supplements each other adding references to
25     each other. None of these is useful by itself, but by
26     adding them up one can get a better perspective of the
27 jontas 1.2 size of the software. The length itself don't tell
28     anything of how large the completed software will be, but
29     together with functions and complexity one can understand
30     the size of the software. Once the size of the software is
31     established one may come with effort estimations, and
32     based on those make a budget for what resources the
33     project will need. Given these three it is possible to get
34     an idea of how productive a programmer is during a time
35     unit. It will not be a perfect answer, but it will be
36     something that could be used to measure deviations in work
37     etc.
38 jontas 1.1 \subsection{Give an example where code length measure can be useful and an
39     example where source code length measure is not useful.}
40 jontas 1.2 Code length is useful if it is not going to be used by
41     itself. One example of this could be if we are interested
42     in how much work is done in a week. Then we could look at
43     loc, and also take into account the complexity and the functions provided
44     (like loc * complexity / functions or something similar).
45     Then loc could be useful.
46    
47     Code length is useless if it is used by itself. For
48     example the statement I am a good programmer since I
49     produce more then n loc per week useless.
50 jontas 1.1 \subsection{Explain what are the main ideas behind Albrecht's Function Points.
51     Discuss advantages and disadvantages of the measure. Motivate.}
52 jontas 1.3 %denna var bra http://www.spr.com/products/function.htm
53 jontas 1.2 The main idea behind FP's are to provide language
54     independent metric that can be used no matter what
55     language are used. Albrech thought it was wrong that the
56     only way to tell effort and cost per effort until he begun
57     was in loc. A often used metric to tell productivity was
58     cost/loc, and that don't tell anything since different
59     languages require different number of loc's to solve the
60     same problem. This cost could be lover if the language
61     requires a lot of code, but the end cost could still get
62     higher if the program takes longer time to complete.
63     The main idea behind FP's is to give ways to
64     tell cost and productivity in a way that is language
65     independent. FP's does satisfy this idea. A easier
66     language will get a lower cost/FP and a greater number of
67     FP's/person\&month then a more complex language.
68    
69     The great advantage with this method is that it is (almost) truly
70     language independent, while a disadvantage would be that
71     if this is established in the beginning of a project and
72     should be used to choose a appropriate language to use, if
73     the language is unfamiliar, then these metrics can't be
74     computed (like FP's/person\&month). Also this way of presenting
75     the result does not take into account training and
76     inexperience while showing the result. Also this should
77     not be used to compare different projects or groups to se
78     the difference between them since this does not take
79     everything into account. Also one might be tempted to
80     always use the language with the highest productivity,
81     this is good in most cases, but sometimes there are other
82     factors to sum in, like speed, security etc.
83 jontas 1.1 \subsection{Describe structural measures presented by Fenton. (Control flow
84     structure, Data flow structure, Data structure). Give an example
85     where you explain how one could use the structural measures
86     (specify which structural measure) to ensure the quality of the
87     software product.}
88 jontas 1.4 %http://sern.ucalgary.ca/~kliewerc/SENG/623/summaries.htm#sum02 var lite halvbra... det bästa jag kunde hitta dock, + F4...
89     Control flow is a diagram with nodes, connected via the
90     directed connections showing the possible routs the
91     program (or actually the flow of data in the program) may
92     take. This could be broken down to several diagrams if it
93     gets to large and complex. This diagram can be used to
94     decide how many test cases is needed to test the program
95     completely.
96    
97     The data flow structure could be shown in a module-call
98     graph. The module-call graph shows what modules calls what
99     other modules, and thereby showing more the flow of
100     information within the program. This may also be used to
101     show coupling and cohesion in the program.
102    
103     The data structure can be measured both locally and
104     globally. Locally it is interesting how much data
105     structure each data item has, and globally it is the
106     amount of data for the system. For the local data
107     structures very little research has been done, but for the
108     global there are more.
109 jontas 1.1 \subsection{Draw the flow graph for the program, which
110     based on the data provided by everyday measurements of the air
111     temperature will calculate the maximum, minimum and the most
112     commonly occurred temperature (the temperature that occurs twice
113     or more) for a given month. Present program paths that has to be
114     executed in order to satisfy the following testing strategies:}
115 jontas 1.5 See appendix a for the diagram.
116 jontas 1.1 \subsubsection{Statement coverage}
117 jontas 1.5 a-b-c-d-e-f-g-h-i-j-k-l-m-n
118 jontas 1.1 \subsubsection{Branch coverage}
119 jontas 1.5 a-b-c-d-e-f-g-h-i-j-k-l-m-n \\
120     a-b-c-b-c-d-e-g-i-j-k-m-n \\
121     a-b-c-d-e-f-g-h-i-j-k-l-m-k-m-n \\
122 jontas 1.1 \subsubsection{Visit each loop}
123 jontas 1.5 %osäker på om detta är rätt...jag har bara antagit att man skall göra ett test så att man kör alla looparna
124     a-b-c-b-c-d-e-f-g-e-f-g-h-i-g-h-i-j-k-l-m-k-m-n
125 jontas 1.1 \subsection{Calculate the cyclomatic complexity of your program. What does
126     this figure tell you?}
127 jontas 1.5 %Cyclomatic complexity (CC) = E - N + p
128     %where E = the number of edges of the graph
129     %N = the number of nodes of the graph
130     %p = the number of connected components
131     %http://www.sei.cmu.edu/str/descriptions/cyclomatic.html
132     Hopefully you mean McCabe's cyclomatic complexity\\
133     % e = no of arcs | n = no of nodes
134     e-n+2 | 18 - 14 + 2 = 18 - 16 = 2 \\ %men vad säger nu detta
135     This tells us the number of tests we have to do to cover
136     each path in the program. It could also be used to give a
137     estimation of how complex the final software will be. If
138     higher then 20 it should be seen as a high risk project,
139     and if higher then 50 as a very high risk project. %nuffrorna kommer från http://www.sei.cmu.edu/str/descriptions/cyclomatic.html
140 jontas 1.1 \section{OO metrics}
141     \textbf{Measuring the use cases}
142 jontas 1.5 %vi skall använda templaten, och bifoga denna...
143 jontas 1.1 \subsection{Measure the use case specifications shown in Design 1 using the
144     chosen use case metrics suite from the lecture}
145 jontas 1.7 See appendix b.
146 jontas 1.1 \subsection{Measure the use case specifications shown in Design 2 using the
147     chosen use case metrics suite from the lecture}
148 jontas 1.7 See appendix c.
149 jontas 1.1 \subsection{Write a short section (up to ½ page) with answers to the following
150     questions:}
151 jontas 1.7 \begin{itemize}
152     \item Which of the two systems presented can be expected to be
153     more complex and why?
154     \item Which of the two systems can be expected to require more
155     effort to be built? Why?
156     \end{itemize}
157 jontas 1.8 We expect design 2 to become more complex, both since
158     it has more use cases, but also since it has higher
159     values (in general) on the metrics suit.
160    
161     We expect design 2 to require more effort to build
162     since it has more use cases and more actions (more
163     functionality). Also since we feel that design 2 has a
164     higher complexity. Also most of the values that we can
165     get out from our metrics suit are greater, both in
166     total and if we count them per use case.
167    
168     We feel that it is hard to make good (accurate)
169     estimations based on this suit only and we also feel
170     that while good estimations on use case level can be
171     made using this suit, it is not a good thing to try to
172     make estimations of the system as a whole only based
173     on this information.
174 jontas 1.6 \\ \\ \textbf{Measuring designs}
175 jontas 1.1 \subsection{Measure the class diagram presented in Design 1 using the CK metrics suite presented on the
176     lecture.}
177 jontas 1.7 See appendix b.
178 jontas 1.1 \subsection{Measure the class diagram presented in Design 2 using
179     the CK metrics suite presented on the lecture.}
180 jontas 1.7 See appendix c.
181 jontas 1.1 \subsection{Measure the code in the files .java from Design 1 with the CK metrics suite
182     presented on the lecture.}
183 jontas 1.7 See appendix b.
184 jontas 1.1 \subsection{ Measure the code in the files .java
185     from Design 2 with the CK metrics suite presented on the lecture.}
186 jontas 1.7 See appendix c.
187 jontas 1.1 \subsection{Write a short section (up to ½ page) with answers to the following
188     questions:}
189 jontas 1.7 \begin{itemize}
190     \item Which of the metrics could not be computed based on the class
191     diagrams? Why?
192     \item Which of the two systems is more complex? Why?
193     \end{itemize}
194     Svar
195 jontas 1.1 \subsubsection{Which method of gathering metrics - from UML designs or source
196     code - is less time consuming?}
197     svar
198     \section{External product attributes}
199     \subsection{Describe how the external product attributes differ from the
200     internal ones. Describe the connection between external and
201     internal product attributes.}
202 jontas 1.5 The internal attributes can be measured from within the
203     system (like loc etc) while for the external attributes
204     one must look at the finished product to se the external
205     attributes. Also in general internal attributes are
206     considered easier to measure (and then predict) then the
207     external attributes.
208    
209     This is partly since the internal attributes can be
210     measured more ``directly'' then the external. For
211     instance loc is easy to count while usability is a lot
212     harder to measure. For the internal attributes one can
213     expect to be able to get absolute values while on the
214     external attributes one can expect them to be less
215     accurate.
216    
217     However several of the internal attributes (if not all)
218     does affect the external attributes in a way that can
219     (in most cases) be predicted. One can for instance say
220     that in a specific solution if the loc is increased
221     (both with comments) then one could expect to get a
222     higher maintainability. Also most of the external
223     attributes can be affected via the internal if the
224     developers keep the external attributes in mind.
225    
226     In most cases (if not always) the customer of the product
227     is more interested in the external attributes. Does this
228     mean that the external attributes are of ``greater''
229     value to the team developing the product?
230    
231     Not always but in many cases. Also one should keep in
232     mind that just because the external attributes are more
233     important that the internal could be forgotten.
234     %\subsection{Assume that you are working at the company that
235     %mainly specializes on developing of web-based applications.
236     %Your manager gives you an assignment to develop a software
237     %quality model for the company. The model should show external
238     %quality attributes, corresponding internal attributes and
239     %metrics. Present the assumptions that you will use while
240     %creating of the quality model. Provide an explanatory text
241     %for your model.} %Jag tyckte inte om att läsa den texten;)
242     \subsection{Assume that you are working at a company that
243     mainly specializes in development of web-based applications.
244     Your manager gives you an assignment to develop a software
245     quality model for the company. The model should show external
246     quality attributes, corresponding internal attributes and
247     metrics. Present the assumptions that you will use while
248     creating the quality model. Provide an explanatory text
249 jontas 1.1 for your model.}
250 jontas 1.6 Assumptions: We are using an iterative development
251     process, we are using function points to measure progress,
252     we are using a good configuration management tool, we are
253     identifying risks before starting a project, we are, but
254     not always using uml for our projects.
255    
256     Since we are working on web-based applications we also
257     assumed that we are selling those to a customer. This made
258     us make a value based quality view. This made us decide
259     that usability, lernability, reusability, maintainability, reliability,
260     is the most important external attributes. The internal
261     attributes are not considered as important, other than to
262     help up the external. Customer satisfaction does supersede
263     this thou. The external attributes has the following
264     impact on customer satisfaction: \\
265     \begin{tabular}{|l|l|l|}
266     \hline
267     Attribute & Importance & Role \\ \hline
268     Usability & High &
269     Decides if the customer fells that he may use\\
270     & & the product or not. The more usable the product\\
271     & & becomes, the higher value it gets (and thereby\\
272     & & higher quality). \\ \hline
273     %hmmm, borde finnas nått bättre sätt...
274     Learnability & High &
275     The quicker the end-user can learn to use the \\
276     & & program, the quicker he feels the value of the\\
277     & & program and does need it. This makes the \\
278     & & customer feels a gain from buying our product \\ \hline
279     Reusability & Medium &
280     This is only important if using agreements like\\
281     & & ``avtal 90'' or similar that gives us the freedom\\
282     & & of the developed artifacts, and may use them in\\
283     & & projects to come. If the customer has no demands\\
284     & & on this, and will own the artifacts then it is \\
285     & & not taken into consideration.\\ \hline
286     Maintainability & Medium &
287     This is only important if we are using the \\
288     & to low &
289     reusability from above. And only to support that\\
290     & & purpose. Otherwise this would not have been a \\
291     & & issue at all. \\ \hline
292     Reliability & High &
293     This is important since a reliable program is \\
294     & & seen as having a higher value. \\ \hline
295     \end{tabular} \\ \\
296     Internal attributes are only important in order to gain
297     the external attributes.
298 jontas 1.1 \end{document}

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