منابع مشابه
An Upper and Lower Bound for Clock Synchronization
The problem of synchronizing clocks of processes in a fully connected network is considered. It is proved that, even if the clocks all run at the same rate as real time and there are no failures, an uncertainty of e in the message delivery time makes it impossible to synchronize the clocks of n processes any more closely than e(1 1/n). A simple algorithm is given that achieves this bound. © 198...
متن کاملNew Upper Bounds for MAX-2-SAT and MAX-2-CSP w.r.t. the Average Variable Degree
MAX-2-SAT and MAX-2-CSP are important NP-hard optimization problems generalizing many graph problems. Despite many efforts, the only known algorithm (due to Williams) solving them in less than 2 steps uses exponential space. Scott and Sorkin give an algorithm with 2 2 d+1 ) time and polynomial space for these problems, where d is the average variable degree. We improve this bound to O∗(2 10/3 d...
متن کاملOn the equivalence of the max-min transportation lower bound and the time-indexed lower bound for single-machine scheduling problems
New observations are made about two lower bound schemes for single-machine min-sum scheduling problems. We find that the strongest bound of those provided by transportation problem relaxations can be computed by solving a linear program. We show the equivalence of this strongest bound and the bound provided by the LP relaxation of the time-indexed integer programming formulation. These observat...
متن کاملStudy of Lower Bound Functions for MAX-2-SAT
Recently, several lower bound functions are proposed for solving the MAX-2-SAT problem optimally in a branch-and-bound algorithm. These lower bounds improve significantly the performance of these algorithms. Based on the study of these lower bound functions, we propose a new, liner-time lower bound function. We show that the new lower bound function is consistently and substantially better than...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Science China Information Sciences
سال: 2014
ISSN: 1674-733X,1869-1919
DOI: 10.1007/s11432-013-5052-x