................................ ................................ ................................ ................................ .... 1 1. INTRODUCTION ................................ ................................ ................................ .................. 1 Definitions of Cross -Docking ................................ ................................ .......................... 7 Existing Tendencies in Supply Chains: the Need for Cross -Docking ............................. 9 Importance of Cross -Docking for Supply Chain Operations ................................ ......... 12 Advantages and Challenges of Cross -Docking ................................ .............................. 16 Advantages of Cross -Docking ................................ ................................ ................ 16 Challenges of Cross -Docking ................................ ................................ ................. 19 Main Dissertation Objectives ................................ ................................ ......................... 20 2 LITERATURE REVIEW ................................ ................................ ................................ ..... 22 General CDT Truck Scheduling ................................ ................................ ..................... 22 Multi -Objective CDT Truck Scheduling ................................ ................................ ........ 42 Uncertainty Modeling in CDT Truck Scheduling ................................ .......................... 47 Miscellaneous ................................ ................................ ................................ ................. 50 Summary of findings ................................ ................................ ................................ ...... 58 Distribution of Reviewed Studies ................................ ................................ .................. 67 The Existing Gaps in the State -of-the-Art................................ ................................ ...... 71 3 PROBLEM DESCRIPTION ................................ ................................ ................................ . 73 Arrival of Trucks ................................ ................................ ................................ ............ 74 Assignme nt of Doors at the CDT ................................ ................................ ................... 75 Internal Operations at the CDT ................................ ................................ ...................... 75 Decay Modeling of Perishable Products ................................ ................................ ........ 79 CDT M anager’s Key Objective ................................ ................................ ...................... 80 An Illustration of the Service of Arriving Trucks ................................ .......................... 81 4 MODEL FORMULATION ................................ ................................ ................................ .. 83 Non-Linear Mathematical Formulation ................................ ................................ ......... 83 Linearization of Non -linear Components ................................ ................................ ....... 87 5 SOLUTION METHODLOGIES ................................ ................................ .......................... 91 Evolutionary Algorithm (EA) ................................ ................................ ........................ 91 vi Steps in the proposed EA algorithm ................................ ................................ ....... 91 Chromosome representation ................................ ................................ ................... 93 Population initialization ................................ ................................ .......................... 94 Parent selection strategy ................................ ................................ ......................... 95 EA operations ................................ ................................ ................................ .......... 96 Fitness evaluation of infeasible individuals ................................ .......................... 101 Survivor selection strategy ................................ ................................ .................... 102 Elitism ................................ ................................ ................................ ................... 103 Termination criteria ................................ ................................ .............................. 104 Variable Neighborhood Search (VNS) Algorithm ................................ ....................... 104 Steps in the proposed VNS ................................ ................................ ................... 105 Representation of solutions ................................ ................................ ................... 106 Initialization of solutions ................................ ................................ ...................... 107 Neighborhood local search ................................ ................................ ................... 107 Neighborhood change ................................ ................................ ........................... 108 Termination criteria ................................ ................................ .............................. 109 Tabu Search (TS) Algorithm ................................ ................................ ........................ 109 Steps in the proposed TS ................................ ................................ ....................... 109 Representation of solutions ................................ ................................ ................... 111 Initialization of solutions ................................ ................................ ...................... 112 Generation of the list of candidate neighbors ................................ ....................... 112 Neighborhood local search for the best solution ................................ ................... 114 Tabu list update ................................ ................................ ................................ ..... 114 Termination criteria ................................ ................................ .............................. 114 Simulated Annealing (SA) Algorithm ................................ ................................ .......... 115 Steps in the proposed SA ................................ ................................ ...................... 115 Representation of solutions ................................ ................................ ................... 117 Initialization of solutions ................................ ................................ ...................... 117 Generation of new solutions ................................ ................................ ................. 118 Boltzmann selection ................................ ................................ .............................. 119 Termination criteria ................................ ................................ .............................. 120 6 NUMERICAL EXPERIMENTS ................................ ................................ ........................ 121 vii Parameter Selection ................................ ................................ ................................ ...... 121 Parameter values for the proposed TSP-CDT mathematical model .................... 121 Parameter values for the c onsidered metaheuristics ................................ ............. 124 Evaluation of the Algorithms against Exact Optimization ................................ ........... 127 Design of the linearized product decay function ................................ .................. 127 Detailed comparison of the solution approaches for the small -size problem instances ................................ ................................ ................................ .............................. 130 Detailed Comparison of the Metaheuristics ................................ ................................ . 133 The values of the objective function and CPU t ime ................................ ............. 133 Objective function and CPU time variations ................................ ........................ 137 Convergence patterns of the algorithms ................................ ............................... 139 Managerial Insights ................................ ................................ ................................ ...... 141 Assessment of the impact of the rate of product decay on the scheduling of trucks 142 Assessment of the impact of the unit waiting cost of trucks on the scheduling of trucks 145 Assessment of the impact of the unit service cost of trucks on the scheduling of trucks 147 Assessment of the impact of the unit cost of product storage on the scheduling of trucks 149 Assessment of the impact of unit cost of the delayed departure on the scheduling of trucks 152 Assessment of the impact of the truck arrival patterns and the CDT door capacity on the scheduling of trucks ................................ ................................ ................................ . 154 7 CONCLUSIONS ................................ ................................ ................................ ................. 158 8 FUTURE RESEARCH NEEDS ................................ ................................ ......................... 162 Consideration of Uncertainties in Truck Scheduling at CDT ................................ ...... 164 Minimax regret method ................................ ................................ ......................... 164 Application of upper and lower bounds ................................ ................................ 166 Cardinality -constrained method ................................ ................................ ............ 167 Scenario analysis ................................ ................................ ................................ ... 167 Sample average approximation ................................ ................................ ............. 167 Multi -Objective Optimization Approaches ................................ ................................ .. 169 Non-Pareto methods ................................ ................................ .............................. 170 viii Approximate Pareto Front -based methods ................................ ............................ 172 Illustration of a Pareto Front ................................ ................................ ................. 174