Comparative Study Ahp Topsis, and Promethee-II of E-commerce Essay Example

A CAR” in E-commerce. Hence, we took this problem into consideration to compare decisions obtained by AHP, TOPSIS and PROMEHTEE II.

METHODOLOGY

Analytical Hierarchy Process (AHP)

Early 1980’s T.L.Satty developed AHP(Analytical Hierarchy Process) which introduces a pair-wise and hierarchical model for decision making process. AHP is one of the most widely used MCDM (Multi Criteria Decision Making) methods. AHP decomposes the decision problem into criteria and sub-criteria forming a hierarchy which gives full understanding to the decision problem. For each criterion and sub-criteria a pairwise matrix taking Satty’s 9-point scale value and compare their relativeness to each other. Finding eigen vector and weight for each matrix which results in the overall ranking to the problem. AHP along with informative data it also takes human judgment into account to ensure the efficiency of the final result. Some of its application includes ranking, prioritization, resource allocation, benchmarking, quality management. The step for implementing AHP process are illustrated as follow:

Step 1: The problem is decomposed into decision making hierarchy in terms of goal, criteria, sub-criteria and alternatives. It is one of the important parts in AHP, to structure the decision problem as a hierarchy.

Hierarchy indicates a relationship between elements of one level with intermediate below level. This relationship prelocates down to lowest level of the hierarchy. At the root of the hierarchy is our goal followed by main criteria, sub-criteria and alternatives. When comparing elements of each level decision maker has to compare with respect to a level below and level above.

Step 2: Data are collected from decision makers and applied to the hierarchical structure, as a pairwise comparison using scale given below. Then decision maker can rate the comparison as

linguistic scale values given in Table 1. Using specially designed format in figure 2 opinion can be collected.

The format indicates that “X” in the given format is “very strong” indicating that B is very strong compared to A. Similarly, each criterion is compared and converted into the quantitative number as shown below.

Step 3: The pairwise comparison for each and every criterion is generated using step 2 and organized into a square matrix where diagonal elements of the matrix are 1.

Step 4: For each comparison matrix principle eigen value and corresponding eigen vector is calculated. The elements of the normalized eigen vector are weights with respect to criteria and sub-criteria. To calculate eigen vector take matrix c[i][j], calculate sum of column sumc[j]. Then modify each matrix element c[i][j] by diving c[i][j] with sumc[j]. Now calculate the sum of row sumr[i] then get weight matrix W[i] by diving sumr[i] with no of row ‘n’.

Step 5: The rating of each alternative is multiplied by the weights of the criteria and aggregated to get the final rating.

Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)

The TOPSIS method was developed by Hwang and Yoon in 1981 and ranks the alternatives based on the distance from the positive and negative ideal solution, i.e. best alternatives should have the shortest distance from positive ideal solution and farthest distance from negative ideal solution.

The positive ideal solution is identified as an alternative that has the best value for all considered criteria whereas the negative ideal solution is identified as worst criteria values. The step for implementing TOPSIS process are illustrated as follow:

Step 1: Construct normalized decision matrix.

Where, Xij and rij are original and

normalized score of decision matrix, respectively

Step 2: Determine the weighted decision matrix. The weighted decision matrix is constructed by multiplying the normalized decision matrix with random weights.

Vij = Wj x rij(1.2)

Where, Wj is the weight of j criterion.

Step 3: Determine the positive ideal (S+) and negative ideal solutions (S–).

S+ = {V1+ ,V2+, A?a‚¬A¦, Vn+ },(1.3)

where:Vj+={(maxi(vij) if j A‘aˆ? J); (mini(vij) if j A‘aˆ? J’)}

S– = {V1– ,V2– ,…, Vn– },A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A A‚A (1.4)

Where:Vj– ={(mini(vij) if j A‘aˆ? J); (maxi(vij) if j A‘aˆ? J’)}

Step 4: Calculate the separation measure for each alternative from the positive ideal and negative ideal solution.

(1.5) (1.6)

Step 5: Calculate the relative closeness to the ideal solution Ci (1.7)

Select the alternative with Ci closest to 1.

Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE)

The PROMETHEE method was developed by Brans and Vincke in 1985. It is an outranking method and a special type of MCDM method which provides ranking order to the decision problems. PROMETHEE I method can only provide partial ordering to the decision problem, whereas PROMETHEE II methods can derive a full ranking of the alternatives. In this paper, PROMETHEE II method is applied to obtain a full ranking of the alternatives to our problem. The step for implementing TOPSIS process are illustrated as follow:

Step 1: Normalize the decision matrix using the following equation:

(i =1, 2…, n; j =1, 2…, m) (2.1)

where Xij is the performance measure of ith alternative with respect to the jth criterion.

Step 2: Calculate the evaluative differences of ith alternative with respect to other alternatives. This step involves the calculation of differences in criteria values between different alternatives

pair-wise.

Step 3: Calculate the preference function, Pj(i, iA‚A?).

Brans and Mareschal proposed six types of preference functions but these preference functions require some parameters, such as preference and indifference thresholds. It is difficult for the decision maker to specify the preference function suitable for each criterion and determine the parameters. To avoid such problem, a simplified function is adopted here:

P j(i, I’) =0 if Rij <= Ri’j(2.2)

Step 4: Calculate the aggregated preference function taking into account the criteria weights.

Aggregated preference function,(2.4)

where wj is the relative importance (weight) of jth criterion.

Step 5: Determine the leaving and entering outranking flows as follows:

Leaving (or positive) flow for ith alternative,(2.5)

Entering (or negative) flow for ith alternative, (2.6)

where n is the number of alternatives.

Step 6: Calculate the net outranking flow for each alternative. (2.7)

Step 7: Determine the ranking of the alternatives depending on the values of A?A?A?(i). The higher value of A?A?A?(i), the better is the alternative. Alternative with highest A?A?A?(i) value is the best alternative.

CONCLUSION

In this comparative study, it is clear that the result obtained from AHP is different than TOPSIS and PROMETHEE II. AHP uses hierarchy structure to define the problem and creates a comparison matrix for all its criteria and sub-criteria, which results a more efficient and better ranking. AHP uses complex method to solve the problem and time taking, whereas TOPSIS and PROMETHEE II are faster and simpler. So, it is quite useful to understand the decision problem first and then decide which MCDM method to apply.

REFERENCES

1. Onut S. Soner S., “Transshipment site selection using the AHP and TOPSIS approaches under fuzzy environment”, European Journal of Operational Research 82 (2), 1552-1559, 2008.
2. Thomas L. Saaty, “The Analytical
   

Hierarchy Process”, Tata McGraw Hill, New York.
Y. J. Lai, T. Y. Liu, C. L. Hwang, “TOPSIS for MODM”, European Journal of Operational Research 76 (3) 486-500, 1994.