Simulation based research, especially for social systems have grown in size and matured in the last two decades. But in spite of high potential impact, adoption and applicability within businesses is relatively low, especially so in the consumer goods industry. This paper indicates some key focus areas in research which, if pursued consistently, are most likely to have the highest impact. These areas are: providing complementary predictive capability to standard market mix models, modelling disruptive changes in the market, increased partnership with the automated personalized algorithms research community and focussing on toolkits which can be directly used by businesses for training and research purposes. It goes on to point out strategies which can be adopted by the research community which will increase the chances of effectively focussing research onto the areas mentioned above.

We study the evolutionary dynamics of brand competition in a market where two firms are competing against each other. A brand's strategy at each period could be either to innovate on its own or to copy the rival or maintain the same position as before. Consumers are heterogenous, they interact with each other, and under bounded rationality choose one of the products every period, based on their characteristics and price. A multi-agent simulation has been designed under three specifications - no network, a random network and a 2-level network. The cases of no networks, random networks and 2-level networks of different densities give very different results in terms of attainment of equilibrium. Moreover, convergence is always more frequent and faster in case of dense 2-level networks and in the case of sparse random networks. It was also noticed that a skew in the distribution of consumers in the characteristics space leads to more variation in equilibrium values as well as in the likelihood of convergence

Commercially available fiber-optic cables allow limited numbers of wavelengths on a single fiber. In this paper we have developed a pragmatic method of implementing all-optical wavelength routed networks using bundles of fibers to realize each communication link. We have explored some interesting features of this approach for dynamic lightpath assignment. We have shown that our approach allows virtual wavelength translation where we may derive some benefits of partial wavelength translation without actually having to change the carrier frequency. This design also allows us to have bundles of varying sizes to accommodate anticipated differences in traffic through different communication links of the network. Finally, we have presented a simple dynamic scheme, based on local information alone, for allocating lightpaths.

In this paper, the properties of Kautz digraphs are studied to evaluate their suitability as topology for optical networks. The properties are compared to those of other topologies proposed in the literature and it has been shown these topologies have better performance in terms of queuing delay in a multihop network. For a given degree of each node and a given diameter of the network, a Kautz digraph supports more nodes than other topologies, like shufflenet or that of using a de Bruijn digraph, and seems to be an attractive design for the physical topology as well.

It is desirable to have low diameter logical topologies for multihop lightwave networks. Researchers have investigated regular topologies for such networks. Only a few of these (e.g., GEMNET) are scalable to allow the addition of new nodes to an existing network. Adding new nodes to such networks requires a major change in routing scheme. For example, in a multistar implementation a large number of retuning of transmitters and receivers anti/or renumbering nodes are needed for GEMNET. We present a scalable logical topology which is not regular but it has a low diameter. This topology is interesting since it allows the network to be expanded indefinitely and new nodes can be added with a relatively small change to the network. We present the new topology, an algorithm to add nodes to the network and two routing schemes.

Most of the logical topologies for lightwave networks available in the literature are not scalable. As a result, for these topologies, the addition of new stations to an existing network is extremely difficult. In this paper, we present a scalable topology for lightwave networks and discuss how the expansion of the network can be handled. We analyze the properties of the proposed network and compare it with other network interconnections. Assuming a multistar implementation, we also address the channel assignment problem.

The diagnosability and diagnosis problems for a model introduced by J. Maeng and M. Malek (1981) of a self-diagnosable multiprocessor system where processors compare the results of tasks performed by other processors in the system are analyzed. A set of criteria is given for determining whether the faulty processors in the system can be diagnosed on the basis of the comparisons, and a polynomial-time algorithm is presented to identify the faulty units of such a system on the basis of the comparison results when the system is known to be diagnosable.>

A synthesis approach to the design of a class of regular networks which provide optimal fault tolerance and are of small diameter is presented. The approach makes it possible to design a regular network in the form of a directed graph when the number of nodes n and the number of connections per node d are given, for any n and d. The designed graph will have node connectivity d and a diameter proportional to (og/sub d/ n).>

This correspondence presents a class of optimally fault tolerant multiprocessor network architecture, based on the networks proposed earlier by Pradhan [71, where the networks are represented by regular digraphs. Because of optimal fault tolerapce, the number of connections per node is precisely related to the degree of fault tolerance the network is designed to provide. The routing of messgges in presence Qf faults is adaptive and unless the number of faults is equal to the degree of fault tolerance the increase in routing delay in presence of faults is minimal.

The problem of diagnosability of a system with three-valued test outcomes was considered in earlier works [1]-[3]. However all these works assume the system to be modeled as in [4]. In this correspondence, we consider a more general model of the system and study the diagnosability criteria in presence of three-valued test outcomes. In this model, each unit is tested jointly by a number of other units of the system as opposed to each test being carried out by a single unit of the system as in [4]. Necessary and sufficient conditions for the diagnosability of a system under this general model have been presented in this correspondence. Throughout the correspondence, diagnosability without repair has been considered.

This correspondence deals with the problem of testing the diagnosmbllity of a system in presence of hybrid faults (that is, when some of the units of the system have failed intermittently and some have failed permanently). Presence of intermittent faults can lead to incomplete diagnosis and usually complicates the diagnosis problem in comparison to permanent fault situation. Alternative characterizations for hybrid fault diagnosability of a system to those originally presented in [3] are derived in this paper. It is shown that these conditions lead to the testing of the hybrid diagnosability of a system with fewer computations than that in [3].