TY - GEN
T1 - Packing resizable items with application to video delivery over wireless networks
AU - Albagli-Kim, Sivan
AU - Epstein, Leah
AU - Shachnai, Hadas
AU - Tamir, Tami
PY - 2013/1/1
Y1 - 2013/1/1
N2 - Motivated by fundamental optimization problems in video delivery over wireless networks, we consider the following problem of packing resizable items (PRI). Given is a bin of capacity B > 0, and a set I of items. Each item j â̂̂ I is of size s j > 0. A packed item must stay in the bin for a fixed time interval. To accommodate more items in the bin, each item j can be compressed to a size p j â̂̂ [0,s j ) for at most a fraction q j â̂̂ [0,1) of the packing interval. The goal is to pack in the bin, for the given time interval, a subset of items of maximum cardinality. PRI is strongly NP-hard already for highly restricted instances. Our main result is an approximation algorithm that packs, for any instance I of PRI, at least items, where OPT(I) is the number of items packed in an optimal solution. Our algorithm yields better ratio for instances in which the maximum compression time of an item is. For subclasses of instances arising in realistic scenarios, we give an algorithm that packs at least OPT(I) - 2 items. Finally, we show that a non-trivial subclass of instances admits an asymptotic fully polynomial time approximation scheme (AFPTAS).
AB - Motivated by fundamental optimization problems in video delivery over wireless networks, we consider the following problem of packing resizable items (PRI). Given is a bin of capacity B > 0, and a set I of items. Each item j â̂̂ I is of size s j > 0. A packed item must stay in the bin for a fixed time interval. To accommodate more items in the bin, each item j can be compressed to a size p j â̂̂ [0,s j ) for at most a fraction q j â̂̂ [0,1) of the packing interval. The goal is to pack in the bin, for the given time interval, a subset of items of maximum cardinality. PRI is strongly NP-hard already for highly restricted instances. Our main result is an approximation algorithm that packs, for any instance I of PRI, at least items, where OPT(I) is the number of items packed in an optimal solution. Our algorithm yields better ratio for instances in which the maximum compression time of an item is. For subclasses of instances arising in realistic scenarios, we give an algorithm that packs at least OPT(I) - 2 items. Finally, we show that a non-trivial subclass of instances admits an asymptotic fully polynomial time approximation scheme (AFPTAS).
UR - http://www.scopus.com/inward/record.url?scp=84872432676&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-36092-3_3
DO - 10.1007/978-3-642-36092-3_3
M3 - Conference contribution
AN - SCOPUS:84872432676
SN - 9783642360916
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 6
EP - 17
BT - Algorithms for Sensor Systems - 8th International Symposium on Algorithms for Sensor Systems, Wireless Ad Hoc Networks and Autonomous Mobile Entities, ALGOSENSORS 2012, Revised Selected Papers
PB - Springer Verlag
T2 - 8th International Symposium on Algorithms for Sensor Systems, Wireless Ad Hoc Networks and Autonomous Mobile Entities, ALGOSENSORS 2012
Y2 - 13 September 2012 through 14 September 2012
ER -