The Asymmetric Traveling Salesman Problem ATSP as well as a the Asymmetric Multi-Stopover Problem AMSP (also Multi-Destination Problem), is intractable (NP -hard). However, using the fastest optimal path algorithms combined with the fastest permutation method enables the real-time solution for problem sizes |S| ≤ 10 (12 including start and target, AMSP) subject to the set S of stopovers that ar...

In this paper we improve the quality of a recently suggested class of construction heuristics for the Asymmetric Traveling Salesman Problem (ATSP), namely the Contract-or-Patch heuristic. Our improvement is based on replacing the selection of each path to be contracted after deleting a heaviest arc from each short cycle in an Optimal Assignment Problem Solution (OAPS) by contracting a single ar...

Memetic Algorithms have been proven to be successful to find the nearest optimum solution to hard combinatorial optimization problems. In this paper, Memetic algorithm is designed for Asymmetric Traveling salesman problem (ATSP). Memetic Algorithm is a combination of power of Genetic algorithm with the powerful local search technique to focus on the population of local optima. Because of perfor...

AIMS In chronic diseases, keeping adherence to medication is very difficult. The objective of this study was to evaluate the impact of administration timing simplification protocol (ATSP) on medication adherence and clinical parameters of cardiovascular diseases. METHODS 210 out-patients with cardiovascular disease, who were taking two or more pills of any type of medication per day for more ...

In this article we consider a variant of the classical asymmetric traveling salesman problem (ATSP), namely the ATSP in which precedence constraints require that certain nodes must precede certain other nodes in any feasible directed tour. This problem occurs as a basic model in scheduling and routing and has a wide range of applications varying from helicopter routing 25], sequencing in exible...

This thesis has two main topics. The first one is design and analysis of approximation algorithms for NP-hard problems that are related to strings. The second topic is algorithms that are related to approximate pattern matching. The first part is about the traveling salesperson problem on directed graphs (ATSP) and the shortest common superstring problem. We give approximation algorithms for se...

Polymers with self-lubricating properties have been employed in various applications as bearing components and tribological surfaces, particularly where the use of liquid lubricant is infeasible, such space-related applications. This study reports on solutions for extreme temperature ranging from ?196 to 300 °C, which simulates operating conditions that materials space will encounter. Tribologi...

In the shortest superstring problem, we are given a set of strings {s1, . . . , sk} and want to find a string that contains all si as substrings and has minimum length. This is a classical problem in approximation and the best known approximation factor is 2 1 2 , given by Sweedyk [19] in 1999. Since then no improvement has been made, howerever two other approaches yielding a 2 1 2 -approximati...

In the Asymmetric Traveling Salesperson Problem (ATSP) the goal is to find a closed walk of minimum cost in a directed graph visiting every vertex. We consider the approximability of ATSP on topologically restricted graphs. It has been shown by Oveis Gharan and Saberi [14] that there exists polynomial-time constant-factor approximations on planar graphs and more generally graphs of constant ori...