network effects, increase in the value of consuming a product if many other consumers use the same product, is a feature of many markets of high-technology products. frequently cited examples of products exhibiting network effects are telecommunication or software products. this research explores the role of network effects in the consumer´s choice of mobile operator in tehran. for our empirica...

A society of agents based on constraint logic as a formalism that could support an agent environment for solving complex problems is explored. Within such society, the rights of individual agents and duties of these agents to others are often expressed in notions like communication, co-operation, negotiation, autonomy, and so on. The motivation comes from the fact that a contract net is essenti...

In fine–grain multithreading, the thread changes in each processor cycle, consecutive instructions are thus issued from different threads, and no data dependencies stall the pipeline. Enhanced fine–grain multithreading maintains a number of additional threads which are used to replace an active thread when it initiates a long–latency operation. Performance improvements due to enhanced multithre...

Scalar multiplication is the most important and expensive operation in elliptic curve cryptosystems. In this paper we improve the efficiency of the Elliptic Net algorithm to compute scalar multiplication by using the equivalence of elliptic nets. The proposed method saves four multiplications in each iteration loop. Experimental results also indicates that our algorithm will be more efficient t...

Focusing on the protection of privacy and nonpublicity of special networks, the CPN model is extended to PCPN by the protocol factor and the formal model. The FPCPN (Formal Protocol Colored Petri Net) is presented to analyze the operation mechanism of protocols. It is introduced by four steps, such as the whole structure, the network element conversion, the conditions of transition triggers/exe...

The paper shows how to synthesise initially marked traps for a Petri Box for the reenement and the scoping operation, from the characteristics of its constituents. Traps are structurally deened subnets of a Petri net with the property that once a trap is marked (i.e., carries at least one token), it will remain marked in any successive marking. Starting point for our paper is the work of R. Dev...

Some guidelines for the comparison of different quantum key distribution experiments are proposed. An improved « plug & play » interferometric system allowing fast key exchange is then introduced. Self-alignment and compensation of birefringence remain. Original electronics implementing the BB84 protocol and allowing user-friendly operation is presented. Key creation with 0.1 photon per pulse a...