IJCSI International Journal of Computer Science Issues, Vol. 3, 2009 ISSN (Online): 1694-0784 ISSN (Printed): 1694-0814 This might take the form of general demographic information or specific information about the need for which a recommendation is sought. 

Of these knowledge types, the last one is the most challenging, as it is an instance of the general usermodelling problem [25]. Despite this drawback, knowledge-based recommendation has some beneficial characteristics. First of all, it is appropriate for casual exploration, because it demands less from the user (compared to the utility-based recommendation). Moreover, it does not involve a start-up period during which its suggestions are of low quality. On the other hand, a knowledge-based recommender cannot "discover" user niches, the way collaborative systems can. However, it can make recommendations as wide-ranging as its knowledge base allows. 

Alternative techniques have been proposed in the literature in order to handle the above issues [11]. Having thoroughly considered their pros and cons, our approach follows a hybrid recommendation technique. Generally speaking, CF and KBR techniques can be combined in hybrid recommendation systems in order to improve their performance. Most commonly, CF is combined with some other technique in an attempt to minimize or avoid the ramp-up problem [3]. 

## 3. The Proposed System

3.1 Transportation plans and evaluation of alternative solutions The recommendation procedure adopted in our approach is highly associated with the selection (by the user) of the appropriate transportation plan. A transportation plan typically defines the user preferences for the upcoming transactions. The five alternative plans offered are: 

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- Express - Economic - Safe - Dependable - User Defined 
It can be easily observed that each of the first four plans declares a specific tension in the recommendation strategy to be followed by the system, in that it either minimizes the overall duration or cost (first two plans), or it retains a high level of safety or dependability (third and fourth plans) of the suggested itineraries. The last choice offers the possibility for a user-customized plan definition. Such a plan may combine parameters from all the above four plans. The selection of one of these plans will influence the recommendation process of our approach for the particular user. 

![0_image_0.png](0_image_0.png)

As shown in Figure 1, which depicts the system's interface for handling a user's request, the user provides input about the loading and delivery terminals, the quantity to be transported, expresses his/her preferences concerning maximum cost and duration of the transaction, and selects the desired transportation plan. By selecting the "userdefined" plan, a new window appears, allowing the user to adjust the criteria (cost, duration, safety, dependability) of his/her transportation request. 

Table 1: Selection criteria for the alternative transportation plans
(safety and dependability take values from the set {very low, low, average, high, very high}). 

Plan **Cost Duration Safety Dependabil**

ity 

Express Any Min Any Any 

Economic Min Any Any Any 

Safe Any Any >Average ≥Low Dependable Any Any ≥ Low > Average Hybrid User 

Defined 

User Defined 

User Defined 

User Defined 
