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GOAL PROGRAMMING: FORMULATION AND GRAPHICAL SOLUTION  599


                                      Figure 14.2 Portfolios that Satisfy the P 1 Goal

                                                     H
                                                 3000
                                                Number of Shares of Hub Properties  2000  Feasible  +  –  Available Funds:  25U + 50H = 80 000
                                                            Priority Level 1 Goal Equation
                                                            with d 1  = d 1   = 0; 0.5U + 0.25H = 700




                                                          +
                                                         d  = 0
                                                          1
                                                 1000
                                                        Portfolios
                                                                      +
                                                        That Will
                                                                     d 1  > 0
                                                      Achieve Priority
                                                       Level 1 Goal
                                                                                               U
                                                     0       1000      2000     3000      4000
                                                                Number of Shares of UK Oil

                                                              þ
                                      also result in the value of d ¼ 0. Thus, the shaded region contains all the feasible
                                                              1
                                      solution points that achieve the priority level 1 goal.
                                         At this point, we have solved the priority level 1 problem. Note that alternative
                                      optimal solutions are possible; in fact, all solution points in the shaded region in
                                                                                                   þ
                                      Figure 14.2 maintain a portfolio risk index of 700 or less, and hence d ¼ 0.
                                                                                                   1
                                         The priority level 2 goal for the Nicolo Investment problem is to find a portfolio
                                      that will provide an annual return of at least £9000. Is overachieving the target value
                                      of £9000 a concern? Clearly, the answer is no because portfolios with an annual
                                      return of more than £9000 correspond to higher returns. Is underachieving the
                                      target value of £9000 a concern? The answer is yes because portfolios with an annual
                                      return of less than £9000 are not acceptable to the client. Thus, the objective
                                      function corresponding to the priority level 2 linear programme should minimize

                                      the value of d . However, because goal 2 is a secondary goal, the solution to the
                                                   2
                                      priority level 2 linear programme must not degrade the optimal solution to the
                                      priority level 1 problem. Thus, the priority level 2 linear programme can now be
                                      stated.

                                      P 2 Problem
                                        Min   d
                                               2
                                        s:t:
                                             25U þ  50H                    80 000  Funds available
                                                          þ
                                           0:50U þ 0:25H   d þ d         ¼   700    P 1 goal
                                                              1
                                                          1
                                                                   þ

                                              3U þ   5H           d þ d ¼   9 000   P 2 goal
                                                                   2   2
                                                         d þ             ¼     0    Maintain achievement of P 1 goal
                                                          1
                                                    þ

                                                          þ

                                               U; H; d ; d ; d ; d   0
                                                    1  1  2  2
                                      Note that the priority level 2 linear programme differs from the priority level 1 linear
                                      programme in two ways. The objective function involves minimizing the amount by
                                      which the portfolio annual return underachieves the level 2 goal, and another
                                      constraint has been added to ensure that no amount of achievement of the priority
                                      level 1 goal is sacrificed.
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