A rough set approach for evaluating vague customer requirement of industrial product-service system_Wenyan Songa
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6692 W. Song et al.<br />
Figure 5. The value and <strong>requirement</strong> around the <strong>customer</strong> activity <strong>of</strong> MRO.<br />
Third, the <strong>customer</strong> value, which is the common focus <strong>of</strong> stakeholders <strong>for</strong> the IPS 2 , is identified in this step by<br />
using the interviews and focus groups. Value here is actually the definition <strong>of</strong> the IPS 2 in terms <strong>of</strong> the <strong>requirement</strong><br />
the <strong>industrial</strong> <strong>service</strong> is going to meet. For instance, to achieve the value <strong>of</strong> ‘High reliability, and long <strong>service</strong> life<br />
<strong>of</strong> air compressor’, the <strong>requirement</strong> ‘Efficient, and reliable MRO with accurate operation in<strong>for</strong>mation <strong>of</strong> air compressor’<br />
has to be fulfilled. That is, the <strong>requirement</strong> is the cost <strong>of</strong> achieving the value. Similarly, the value in the<br />
delivery <strong>of</strong> air compressor is mainly ‘Using immediately without time consuming <strong>for</strong> the starting period’. This<br />
value is related with the <strong>requirement</strong> ‘Filed guidance and training at the starting period’. Thus, in this way, the rest<br />
<strong>of</strong> <strong>requirement</strong>s can be acquired.<br />
Fourth, Affinity Diagram is used to structure <strong>customer</strong> <strong>requirement</strong>s. The elicited <strong>customer</strong> <strong>requirement</strong>s are firstly<br />
interpreted into simple and representative expressions. For example, ambiguous <strong>requirement</strong> in the Figure 5 (Efficient,<br />
and reliable MRO with accurate operation in<strong>for</strong>mation <strong>of</strong> air compressor) is represented by three concrete sub-<strong>requirement</strong>s,<br />
i.e. ‘Disassembly and reassembly easily’, ‘24-h <strong>service</strong> (Feedback in 30 min, and on-site with spare parts in 3 h)’<br />
and ‘Remote monitoring, early warning and failure diagnosis’. Similarly, other <strong>requirement</strong>s could be also interpreted.<br />
Then, all the phrases would be bundled into many affinity groups, and the header with its group members could be<br />
obtained in Figure 6.<br />
5.1.2 IPS 2 <strong>requirement</strong> prioritisation<br />
Step 1 Construct pair comparison matrix and test consistency<br />
An expert team is built <strong>for</strong> the evaluation IPS 2 <strong>requirement</strong> which consists <strong>of</strong> five experienced team members. They are<br />
procurement engineer, operator, end user, MRO engineer and IPS 2 designer. The work experience <strong>of</strong> experts ranged<br />
from 4 to 10 years in their own domains. Pair-wise comparisons between IPS 2 <strong>requirement</strong>s are conducted in each<br />
hierarchy until each comparison matrix can get th<strong>rough</strong> the consistency test.<br />
Take the R 4 (Guarantee and optimisation <strong>of</strong> normal operation), <strong>for</strong> example (R 41 : Compressor flow P 7m 3 /min,<br />
discharge pressure P 0.8 Mpa; R 42 : Integrated structure; R 43 : no vibration and air flow pulse, noise < 75 dB; R 44 : Simple<br />
and com<strong>for</strong>table manipulation; and R 45 : Energy saving rate: 18–35%), to illustrate computation process. The five<br />
experts’ comparison matrixes <strong>of</strong> <strong>requirement</strong> importance <strong>for</strong> R 4 are as follows: