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In future wireless ad hoc networks, transactions are expected to become one of the primary types of flows. Transactions require only a small number of packets to complete. Hence, providing optimal (shortest path) routes to such transactions consumes more energy than the actual data transfer. Conventional shortest path routing protocols are, thus, unsuitable for routing transactions. In this paper, we present a novel architecture, called TRANSFER, for transactions routing in large-scale wireless ad hoc networks. In our approach, we aim to reduce the total energy consumption by transactions as opposed to finding shortest path routes. Our architecture uses a hybrid approach, in which each mobile node obtains information about nodes in its proximity (zone), up to R hops away, using a proactive link-state protocol. Beyond the proximity, we introduce the novel notion of contacts that act as shortcuts to reduce the degrees of separation between the source of the transaction and the destination. We propose an efficient on-demand protocol for contact selection that does not assume knowledge of location information. Contacts are used during transactions and queries to discover valid routes in an energy-efficient manner. Extensive simulations are used to evaluate the performance of our protocol in terms of energy consumption and success rate. We compare our architecture to flooding, dynamic source routing (DSR), zone-routing protocol (ZRP), and two power-aware schemes. Our results show substantial power savings for our contact-based protocol, especially for large ad hoc networks. Index Terms--Adhoc networks, contact-based architecture, energy efficiency, network simulation, routing protocol.

A novel hybrid routing protocol - the Two-Zone Routing Protocol (TZRP) as a non-trivial extension of Zone Routing Protocol is proposed. TZRP uses two different zones to decouple the protocols ability to adapt to traffic characteristics from the ability to adapt to mobility.

Two of the fundamental issues in designing protocols for message passing between mobile agents (MAs) are tracking the migration of the target agent and forwarding messages to it. Even with an ideal fault-free network-transport mechanism, messages can be dropped during MA migration. Therefore, in order to provide reliable message delivery, protocols need to overcome message loss caused by asynchronous operations of agent migration and message forwarding. In this paper, two known message forwarding approaches, namely push and pull, are explored to design adaptive and reliable message delivery protocols. Based on a commonly used MA tracking model, the pros and cons of these two approaches are evaluated, both qualitatively and quantitatively. The comparative performance evaluation is presented in terms of network traffic and delay in message processing. We also propose improvements to the pull approach to reduce network traffic and the message delay. We conclude that with different message passing and migration patterns and varying requirements of real-time message processing, specific applications can select different message delivery approaches to achieve the desired level of performance and flexibility. Index Terms--Mobile agents (MAs), pull, push, reliable message delivery.

A novel, efficient and low cost start-up and restart synchronization approach for TDMA environments is presented by focusing on bus-based communication protocols. The approach utilizes information about a node's message length that forms a unique sequence to achieve synchronization such that communication overhead can be avoided.

Different static and dynamic schemes are explored to select the virtual lanes for outgoing messages and mix the load among them without restricting any particular type of message to be carried only by a particular virtual network. In addition, the network latency, the number of message buffers per virtual lane, and the depth of network interface output queues affect the relative performance of various virtual lane selection algorithms are examined.

There was generally a significant relationship between the hypothesized mediators and perceived learning for online courses. Studies indicate that outcomes of online courses improved when professors structured them to support the growth of a learning community, by being available online to interact with students, and by using collaborative learning strategies.

A new transmission protocol that uses a joint lossless-source and channel coding scheme (JARQ) is introduced. The protocol is evaluated by analyzing its throughput, and simulation results are presented that compare the throughput achieved with this protocol with that of conventional ARQ protocols.

Negotiation protocols almost define simple contracts consisting of one or a few independent issues. A simulated annealing-based approach, a refined version based on a parity-maintaining annealing mediator and an unmediated version of the negotiation protocol is presented.

The bulk synchronous task-scheduling problem (BSSPO) is known as an effective task scheduling problem for distributed-memory machines. A proof of NP-completeness of the decision counterpart of BSSPO is presented.

The way in which Internet won the religious war about computer communication protocol standards in Scandinavia is discussed. It is important that the development of these technologies must combine and balance the use of gateways and standards in a proper way.