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DARPA ULTRALOG Final Report - Industrial and Manufacturing ...

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Manuscript for IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 16<br />

w<br />

*<br />

i<br />

=<br />

T<br />

p∈K<br />

*<br />

i<br />

∑<br />

T<br />

n(<br />

i)<br />

*<br />

p<br />

ω<br />

n(<br />

i)<br />

(22)<br />

Component’s decision<br />

v<br />

*<br />

i<br />

*<br />

1 ( Ti<br />

− Ri<br />

( t)<br />

= f<br />

− i ( )<br />

(23)<br />

L ( t)<br />

i<br />

4.2 Analysis<br />

Resource manager’s bidding function b n (T) in (19) can be composed referring to the solution<br />

algorithm of fractional knapsack problem. In the fractional knapsack problem, there are multiple<br />

items that can be broken into fractions. Given unit weight <strong>and</strong> unit value of each item, the<br />

problem is to determine the amount of each item so as to maximize total value subject to a<br />

weight capacity. The fractional knapsack problem can be easily solved by a greedy algorithm,<br />

i.e., take as much as possible of the item that is the most valuable per unit weight until the<br />

capacity is reached. Similarly, b n (T) can be composed using a greedy algorithm. As b i (T i ) in (18)<br />

is a piecewise-linear increasing concave function, take the most valuable piece per unit T i among<br />

the first available pieces until all pieces are taken. This greedy algorithm leads building the<br />

resource manager’s bidding function in O(|K n | 2 ), where |X| denotes the cardinality of set X.<br />

Similarly, resource manager’s decision problem in (21) can be solved in O(|K n | 2 ), using the<br />

greedy algorithm except that (fractional) pieces are taken until a capacity is reached. So, the<br />

complexity of all resource managers’ local problems is O(|A| 2 ) in the worst case when |N|=1.<br />

The seller’s decision problem in (20) is simply a single variable problem, which can be solved<br />

using diverse search methods depending on the structure of objective function. As each b n (T) is<br />

piecewise-linear increasing concave function, ∑b n (T) is also a piecewise-linear increasing<br />

concave function <strong>and</strong> its number of pieces is proportional to |A|. To compose ∑b n (T) from each

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