## 8 Creation and Interpretation of the Value Curves  
### Finalization of Values Curves through the Assignment of Performance Levels  
The categories of machines defined in Section 5, the competing factors identified in Section 6, and the information of the related performance gathered in Section 7 were summarized, as shown in the value curves depicted in Figure 6. More precisely, the performances observed for each competing factor and for each family of machines were consistently transformed in a 1-5 ordered scale. The level of performances was attributed by directly comparing the quantitative performances where available (e.g., the unit price for cheapness, the productivity, the storing capacity) and by considering all the information available from the literature, patents, and web searches when it came to qualitative requirements. The 1-5 scale was introduced to enable comparisons across all the requirements, including the quantitative ones that are inherently featured by different units of measurements. The value 5 (1) of the scale was assigned to the system that presents the highest (lowest) performance and to those with a similar level of fulfillment for each competing factor. In addition, as a rule of thumb, the competing factors were ordered in a way to minimize the number of intersections between the lines and, thus, achieve a clearer display of the results. At this point, it is necessary to highlight that since each value curve is representative of a machine category and not of a single machine, each curve should show a variability. Indeed, for instance, there are _self-propelled_ solutions that have lower productivity than some _mounted_ ones. However, these peculiar cases are unrepresentative of the large majority of machines belonging to the corresponding category. Therefore, the indication of variability was not included in the diagram. Each line represents the characteristic requirements of a machines' category and this can be compared with the requirements fulfilled by other categories. Figure 6: Value curves for the eight categories of harvesting machines for shell fruits. The bulleted list that follows aims at explaining, for each competing factor, how each family of machines was associated with a 1 to 5 level of performance. The results are graphically shown in Figure 6.  
* _Cheappness: M/P_ machines are the cheapest (price \(<\) 400 \(\epsilon\)) (level 5). _V/P_ machines follow that are slightly more expensive because they need an engine (price around 600-1300 \(\epsilon\)) (level 4). _M/M_ machines belong to another price category ranging from 5000 \(\epsilon\) to 18,000 \(\epsilon\) (level 3). _V/T_ and _V/M_ machines reach slightly higher prices (around 8000-20,000 \(\epsilon\)) (level 2). _M/T_ and _self-propelled_ machines are the most expensive machines and their prices range from 22,000 \(\epsilon\) and can even exceed 60,000 \(\epsilon\) (level 1). * _Suitability for small orchards_: The performances for this competing factor have been qualitatively attributed based on the most common characteristics of small orchards, e.g., mountainous areas and irregular ground, and the conditions traditionally faced by people operating in small orchards. Indeed, the high versatility of _portable_ solutions makes them the most suitable machines for small orchards (level 5). The least appropriate machines are, conversely, the least versatile _self-propelled_ and _M/T_ (level 1). The _V/T_ and _V/M_ (level 4) are preferable than _M/M_ (level 2) since the former are more appropriate for irregular ground. * _Suitability for working on slopes_: Lighter machines were considered the most appropriate for working on slopes; therefore, _portable_ machines achieve the best level of performance (level 5). The worst performance was assigned to _M/T_ (level 1) since these machines are designed for working in flat areas, they are heavy, and they have no traction system of their own. _Self-propelled_ machines (level 2) can work in sloping ground but not with the same effectiveness as _mounted_ or _trailed_ machines.