Description and composition of bio-inspired design patterns: a complete overview <s> Related work <s> The Generalized Assignment Problem consists in assigning a set of tasks to a set of agents with minimum cost. Each agent has a limited amount of a single resource and each task must be assigned to one and only one agent, requiring a certain amount of the resource of the agent. We present new metaheuristics for the generalized assignment problem based on hybrid approaches. One metaheuristic is a MAX-MIN Ant System (MMAS), an improved version of the Ant System, which was recently proposed by Stutzle and Hoos to combinatorial optimization problems, and it can be seen has an adaptive sampling algorithm that takes in consideration the experience gathered in earlier iterations of the algorithm. Moreover, the latter heuristic is combined with local search and tabu search heuristics to improve the search. A greedy randomized adaptive search heuristic (GRASP) is also proposed. Several neighborhoods are studied, including one based on ejection chains that produces good moves without increasing the computational effort. We present computational results of the comparative performance, followed by concluding remarks and ideas on future research in generalized assignment related problems. <s> BIB001 </s> Description and composition of bio-inspired design patterns: a complete overview <s> Related work <s> In this paper we review the exact algorithms based on the branch and bound approach proposed in the last years for the solution of the basic version of the vehicle routing problem (VRP), where only the vehicle capacity constraints are considered. These algorithms have considerably increased the size of VRPs that can be solved with respect to earlier approaches. Moreover, at least for the case in which the cost matrix is asymmetric, branch and bound algorithms still represent the state-of-the-art with respect to the exact solution. Computational results comparing the performance of different relaxations and algorithms on a set of benchmark instances are presented. We conclude by examining possible future directions of research in this field. <s> BIB002
The idea of engineering self-organising systems has attracted many researchers since 2004.  present a set of biologically-inspired primitives that describe how organising principles from multi-cellular organisms may apply to multi-agent systems. That paper was a first attempt towards assembling a catalogue of primitives for multi-agent control. However, those primitives are not presented together with an implementation process or by taking into consideration the different scenarios to which the primitives can be applied. It is then difficult to use them in a systematic way for engineering artificial self-organising systems. BIB001 propose a taxonomy to classify self-organising mechanisms and describe a set of mechanisms. These descriptions can drive the implementation of these mechanisms, but they are not expressed as patterns and cannot be used systematically. However, that work motivates to go further and raises new questions: What are the problems that each mechanism can solve? To what solution contributes each pattern? What are the main trade-offs to consider in the implementation? To answer those questions and make the self-organising mechanisms applicable more systematically, some authors have focused on proposing descriptions of self-organising mechanisms under the form of software design patterns  . The idea of the design pattern structure makes it easy to identify the problems that each mechanism can solve, the specific solution that it brings, the dynamics among the entities and the implementation.  propose a set of design patterns for self-organising systems all related with the ant colonies behaviour, together with the idea that a mechanism can be composed from other mechanisms. The provided model, however, presents too many constraints to be generalised and the examples of usage are not related to self-organising systems. Based on the set of mechanisms proposed in BIB001 , BIB002 discuss how intended multi-agent systems (MAS) dynamics can be modelled and refined to decentralised MAS designs, proposing a systematic design procedure that is exemplified in a case study. De Wolf (2007) presents an extended catalogue of mechanisms as design patterns for self-organising emergent applications. The patterns are presented in detail and can be used to systematically apply them to engineering self-organising systems. However, relations among the patterns are missed, i.e. the authors do not describe how patterns can be combined to create new patterns or adapted to tackle different problems.