210 likes | 310 Views
Internet Engineering Czesław Smutnicki Discrete Mathematics – Location a nd Placement Problems i n Information a nd Communication Systems. PRESENTATION OUTLINE. location and placement problems, solution methodology, classical RND problems, more realistic RND problem,
E N D
Internet Engineering Czesław Smutnicki DiscreteMathematics– Location and Placement Problems in Information and Communication Systems
PRESENTATION OUTLINE • location and placement problems, • solution methodology, • classical RND problems, • more realistic RND problem, • map topology, cell model,coverage, • the optimization problem, • solution methods, • computer experiments, • conclusions
LOCATION AND PLACEMENT PROBLEMS • VLSI floorplanning, • service or warehouse or facility location (known as QAP, Quadratic Assignment Problem), • databases and network services migration and replication, • antenna placement in mobile telecommunication, • cell planning for cellular networks, • distribution of access points in wireless networks, • ad hoc networks, • planning of distribution of wireless sensors • …
SOLUTION METHODOLOGY. TIME OF CALCULATIONS/COST OF CALCULATION CURSE OF DIMENSIONALITY Please wait. Calculations will last 3 289 years NP-HARDNESS LAB INSTANCE 5..20 VARIABLES ! ! ? NONLINEAR FUNCTION OF 2000 VARIABLES !!! INSTANCE FROM PRACTICE
SOLUTION METHODOLOGY. CURRENT STATE IN DISCRETE OPTIMIZATION • Theory of NP-completness • Polynomial-time algorithms • Exact methods (B&B, DP, ILP, BLP, MILP, SUB,…) • Packages and solvers (LINDO, CPLEX, ILOG, …) • Approximate methods (…): heuristics, metaheuristics, meta2heuristics • Quality measures of approximation (absolute, relative, …) • Analysis of quality measures (worst-case, probabilistic, experimental) • Calculation cost (pessimistic, average, experimentally tested) • Approximation schemes (AS, polynomial-time PTAS, fully polynomial-time FPTAS) • Competitive analysis (no-line algorithms) • Inapproximality theory • Useful experimental methods (…) • „No free lunch” theorem • Public benchmarks • Parallel and distributed methods: new class of algorithms • Simulation
SOLUTION METHODOLOGY. CURRENT STATE IN DISCRETE OPTIMIZATION
SOLUTION METHODOLOGY. APPROXIMATE METHODS • constructive/improvement • priority rules • random search • greedy randomized adaptive • simulated annealing • simulated jumping • estimation of distribution • tabu search • adaptive memory search • variable neighborhhod search • evolutionary, genetic search • differential evolution • biochemistry methods • immunological methods • ant colony optimization • particle swarm optimization • neural networks • threshold accepting • bee search • path search • beam search • scatter search • harmony search • path relinging • adaptive search • constraint satisfaction • descending, hill climbing • multi-agent • memetic search • intelligent wather drops • harmony search • electromagnetic search • * * * * * METHODS RESISTANT TO LOCAL EXTREMES
n x x CELL MODEL x m x x x k RADIO NETWORK DESIGN (RND) PROBLEM.CLASSICAL MATHEMATICAL MODEL
RADIO NETWORK DESIGN (RND) PROBLEM. CLASSICAL MATHEMATICAL MODEL PROBLEM DATA SOLUTION CONSTRAINTS GOAL FUNCTION Percentage of covered region, =2
RADIO NETWORK DESIGN (RND) PROBLEM. CLASSICAL MATHEMATICAL MODEL cont. MULTIPLE CRITERIA CASE • NP-hard problems • Balance between criteria • Scalarising • Pareto set, Pareto frontier • Approximate algorithms • Approximation of Pareto frontier
MORE REALISTIC RND PROBLEMS. CELL MODEL Ri(Pi) Ci(Pi) Ci(Pi) Ci(Pi) Pi Pi Pi Pi
MORE REALISTIC RND PROBLEMS. COVERAGE CHECKING POINT (pi, qi) SOLUTION; ANTENNA LOCATED IN POINTS FROM K; POWERS ARE Pi
THE OPTIMIZATION PROBLEM GOAL FUNCTION VALUE UNDER CONSTRAINTS
SOLUTION METHODS. DECOMPOSITION: LOWER LEVEL GOAL FUNCTION VALUE UNDER CONSTRAINTS
SOLUTION METHODS. DECOMPOSITION: MIDDLE LEVEL GOAL FUNCTION VALUE UNDER CONSTRAINTS
SOLUTION METHODS. DECOMPOSITION: UPPER LEVEL GOAL FUNCTION VALUE
SOLUTION METHODS • LOWER LEVEL: EXACT SOLUTION • MIDDLE LEVEL: KNAPSACK (APPROXIMATION) • UPPER LEVEL: SIMULATED ANNEALING, AUTOTUNNIG VERSION • WITH BOLTZMAN COOLING SCHEME AND SOME STEPS IN FIXED • TEMPERATURE; SPECIFIC NEIGHBORHOOD BASED ON LOCAL VICINITY OF THE LOCATION POINT
CONCLUSIONS AND FURTHER RESEARCH • the algorithm offers more realistic model of RND problem • the model is smaller size and scalable • new constraints can be embedded in the model • model can be extended to multicriteria case • further research are needed for evaluating the quality of the proposed methods on broader test of instances • approximate solutions should be compared to exact solutions (CPLEX package) to evaluate their quality
Thank you for your attention LOCATION AND PLACEMENT PROBLEMS IN INFORMATION AND COMMUNICATION SYSTEMS Czesław Smutnicki