This work proposes a distributed dynamic channel assignment of multi-channel MAC protocol in Ad-Hoc networks. Major characteristics of the proposed protocol are: (a) each mobile node is equipped with two network interfaces, (b) no time synchronization is needed, (c) distribution channel assignment. The proposed protocol reduces the cost of channel negotiation by considering the property that a connection generates multiple frames for transmitting and can assign channel information faster. Compared with other multi-channel MAC protocols, the proposed algorithm allows the whole network channel allotment be stable quickly. The performance evaluation is conducted on NS-2. Simulation results show that the proposed protocol can reduce the cost of channel negotiation significantly, increase the network throughput.

In the multiratecasting problem in wireless sensor networks, the source sensor is usually required to report to multiple destinations at dif- ferent rates for each of them. We present a MST-based rate-aware cost-efficient multiratecast routing protocol (MSTRC). The proposed MSTRC examines only one set partition of destinations at each for- warding step. A message split occurs when the locally-built minimum spanning tree (MST) over the current node and the set of destina- tions has multiple edges originated at the current node. Destinations spanned by each of these edges are grouped together, and for each of these subsets the best neighbor is selected as the next hop. We also suggested a novel face recovery mechanism to deal with void ar- eas, when no neighbor provides positive progress toward destinations. It constructs a MST of current node and destinations without the progress via neighbors, and for each set partition of destinations cor- responding to an edge e in MST, the face routing keeps going until a node that is closer to one of these destinations is found, allowing for greedy continuation, while the process repeats for the remaining desti- nations similarly. Our experimental results demonstrate that MSTRC is highly rate-efficient in all scenarios, and unlike existing solutions, it is adaptive to destination rate deviations.

No description available.

Current research in multi-agent systems (MAS) has advanced to the development of open MAS, which are characterized by the heterogeneity of agents, free exit/entry and decentralized control. Conflicts of interest among agents are inevitable, and hence automated negotiation to resolve them is one of the promising solutions. This thesis studies three modifications on alternating-offer bargaining protocols for automated negotiation in open MAS. The long-term goal of this research is to design negotiation protocols which can be easily used by intelligent agents in accommodating their need in resolving their conflicts. In particular, we propose three modifications: allowing non-monotonic offers during the bargaining (non-monotonic-offers bargaining protocol), allowing strategic delay (delay-based bargaining protocol), and allowing strategic ignorance to augment argumentation when the bargaining comprises argumentation (ignorance-based argumentation-based negotiation protocol). <p>Utility theory and decision-theoretic approaches are used in the theoretical analysis part, with an aim to prove the benefit of these three modifications in negotiation among myopic agents under uncertainty. Empirical studies by means of computer simulation are conducted in analyzing the cost and benefit of these modifications. Social agents, who use common human bargaining strategies, are the subjects of the simulation. <p>In general, we assume that agents are bounded rational with various degrees of belief and trust toward their opponents. In particular in the study of the non-monotonic-offers bargaining protocol, we assume that our agents have diminishing surplus. We further assume that our agents have increasing surplus in the study of delay-based bargaining protocol. And in the study of ignorance-based argumentation-based negotiation protocol, we assume that agents may have different knowledge and use different ontologies and reasoning engines. <p>Through theoretical analysis under various settings, we show the benefit of allowing these modifications in terms of agents expected surplus. And through simulation, we show the benefit of allowing these modifications in terms of social welfare (total surplus). Several implementation issues are then discussed, and their potential solutions in terms of some additional policies are proposed. Finally, we also suggest some future work which can potentially improve the reliability of these modifications.

Call admission control (CAC) extends the capabilities of Quality of service (QoS) tools which protect voice traffic from the negative effects of other voice traffic. It does not allow oversubscription of a Voice over Internet Protocol (VoIP) network. To achieve better performance for efficient call admission control, various dynamic routings are being proposed. In the dynamic routing mechanism, the condition of the network is learned by observing the network condition via the probe packets and according to the defined threshold, routes are chosen dynamically. In such schemes, various combination of route selection is used such as two routes are used where one is fixed and other is random or two random routes are chosen and after observation one is chosen if it passes the test. Few schemes use a route history table along with the two random routes. But all have some issues like it selects random routes (not considering the number of hops), does not process memorization before admission threshold test, it calculates all selected paths regardless of the fact that they are selected or not, thereby wasting central processing unit (CPU) time and since these uses two routes so obviously the call admission probability is less. In this thesis work, a new dynamic routing scheme is proposed which considers a routing history table with endpoint admission control increasing the call admission probability, makes call establishment time faster and it saves valuable CPU resources. The proposed scheme considers a combination of three routes with routing history table--one is the direct route and the other two are selected randomly from all available routes and the routing history table is used to memorize the rejected calls. CAC tests like Admission Threshold were performed on the selected routes. Various parameters such as delay, packet loss, jitter, latency etc from the probe packets are used to carry out the tests. Performance of the proposed scheme with respect to other dynamic routing schemes is studied using a mathematical / analytical model. Also, effect of arrival rate probe packets on utilization, busy period, waiting period, acceptance probability of calls, probe packets, and the number of successful calls was also studied. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering. / "July 2006."

Since uncertainty and irreversibility are inherent, environmental policy involves the problems of timing of implementation. Environmental policy based on cost-benefit analysis using certainty equivalent presents values can be misleading under the combined effect of irreversibility and uncertainty. Using real options method, the thesis analyzes the timing of early action investment in Canada's Kyoto commitment. Early action investment in emission reductions is irreversible. The thesis uses a simple two-period model, and then lays out a corresponding continuous-time model to show that under technological uncertainty, early action investment should be delayed until more information - the results of R&D - is revealed. In particular, the more uncertain the outcome of research, the more the firm should delay early action investment. The thesis argues that Canada's Kyoto commitment is well intentioned but not wisely implemented: early action investment on emission reductions may not be efficient. The results suggest that a more gradual Kyoto program would be favourable.

Post-harvest seedcoat darkening is a major problem in many pulses, including common bean (</i>Phaseolus vulgaris</i> L.). In some bean market classes, such as pinto, beans that have a darkened seedcoat are discounted in the market place as it is assumed that the beans are old and will be hard-to-cook (HTC). Pinto genotypes that darken more slowly than conventional pinto beans would be more desirable and have been identified in the bean breeding program at the University of Saskatchewan. <p>To study the slow-darkening trait, a quick, reliable, and inexpensive screening method that would not affect seed germination would be beneficial. Three potential protocols to accelerate seedcoat darkening were examined. The greenhouse protocol was conducted in the greenhouse by placing the bean seeds in polybags with a 1 cm2 piece of moistened felt. For the UV light protocol, bean seeds were placed 10 cm below an UV lamp which had a wavelength of 254 nm. For the cabinet protocol, bean seeds were placed in a cabinet set at 30¢ªC, 80% relative humidity, and full fluorescent lights. Color measurements were taken routinely using a Hunter Lab colorimeter. All three methods were successful in distinguishing darkening beans from slow-darkening beans although the UV light protocol was considered to be superior to the greenhouse and cabinet protocol as the UV light protocol was quick, consistent over years, and the most economical. Unlike the greenhouse and the cabinet protocols, the UV light protocol did not affect seed germination following accelerated darkening. <p>The stability of the slow-darkening trait was further investigated in genotype by environment (g x e) studies across different indoor and outdoor environments. In the g x e study across different field environments, it was found that prior to accelerated seedcoat darkening the g x e interaction was significant. Following accelerated seedcoat darkening, environment and genotype were both significant and g x e was not. The slow-darkening genotypes had lighter seedcoats than the darkening genotypes and those field sites that had more favorable weather had lighter seedcoats. For the g x e study across indoor and outdoor environments, when the genotypes were split into either slow-darkening or darkening, the g x e interaction was not significant and the slow-darkening genotypes had lighter seedcoats. <p>Genetic control of the slow darkening trait was determined. For crosses between slow-darkening genotypes and CDC Pintium, the F2 populations segregated 3 darkening : 1 slow-darkening with distinct bimodal distribution. This indicated that seedcoat darkening was controlled by a single gene and darkening was dominant over slow-darkening. For both slow-darkening by slow-darkening crosses, the F2 populations¡¯ L* values were unimodal, normal distributions, indicating there may be modifying genes for the slow-darkening trait.

Since uncertainty and irreversibility are inherent, environmental policy involves the problems of timing of implementation. Environmental policy based on cost-benefit analysis using certainty equivalent presents values can be misleading under the combined effect of irreversibility and uncertainty. Using real options method, the thesis analyzes the timing of early action investment in Canada's Kyoto commitment. Early action investment in emission reductions is irreversible. The thesis uses a simple two-period model, and then lays out a corresponding continuous-time model to show that under technological uncertainty, early action investment should be delayed until more information - the results of R&D - is revealed. In particular, the more uncertain the outcome of research, the more the firm should delay early action investment. The thesis argues that Canada's Kyoto commitment is well intentioned but not wisely implemented: early action investment on emission reductions may not be efficient. The results suggest that a more gradual Kyoto program would be favourable.

No description available.

There is an increasing demand for reliable wireless communication in embedded real time systems.  Various communication requirements make the development and deployment of applications that rely on the existence of a protocol stack a challenging research and industrial field of activity. Suitable protocol stacks need to be designed and implemented on new hardware platforms and software structures. Applications that exchange packets over a wireless medium have to deal with time constraints, error checks and have to be aware of energy consumption.   PIE (Platform for Intelligent Embedded Systems) is an experimental platform developed at Halmstad University for educational purposes.  It is a robotic vehicle with wireless communication capabilities that can be used to experiment with traffic scenarios where the vehicles communicate in order to cooperate, for example to avoid hazards or to build platoons.   This thesis addresses the design and implementation of a protocol stack suitable for the PIE platform in the area of vehicle alert systems. Requirements include low latencies along with low packet loss ratios.  The thesis addresses also experimenting with reactive objects for programming network software.