In this work, a new key exchange protocol for IP-based mobile networks is introduced. This protocol is called KEPSOM (Key Exchange Protocol Supporting Mobility and Multihoming). The goals of designing KEPSOM are to develop key exchange protocol proposal characterized by its secrecy, simplicity, efficiency, resistivity, and its ability to support mobility and multihoming. The protocol requires only two roundtrips. The design limits the private information revealed by the initiator. An old security association (SA) can be replaced with a new one by rekeying without the need of restarting the protocol with a new session. On the other hand, the changes in IP address due to mobility or multihoming need not to restart the protocol with a new SA session. The proposed protocol can also support key exchange in hybrid wireless network, in which the mobile node can operate in both Ad Hoc and Base Station-oriented wireless network environments using different transmission modes. KEPSOM has been analyzed and proven secure. Several tests have been done to measure and evaluate the performance of the protocol. In these tests, it is found that the required time for rekeying is about 27% of the total required time for exchanging the keys. And the required time to detect and update the change in IP address, which may occur due to mobility or multihoming, is less than 10% of the total required time to establish a new SA sessions.
The status of the infrastructure of the transport system and then mobility in the governorate of Anbar is deplorable. Therefore, it requires two types of solutions in two phases. This study concerned with the first phase, which is represented by solving the problem of the inadequacy infrastructure in terms of availability between the cities, and work to develop it toward being maximally connected. So, generally speaking this study aimed to facilitate mobility through this network, by improving the accessibility in term of connectivity. The analysis process in this study, have twin objectives: first, to determine how much new linkages we need for our network to be maximally connected as a first stage? Second, Building a legislative framework lends the weight for decision makers in transport agency to take tough decision built up on ranking the new proposed linkages according to their relative values in providing access to the network, and the increment in comparable nodal accessibility due to the new additions. So, there is need for more sensible decisions based on more accurate analysis for deciding the optimum priorities for the new linkages to take place in the stage of development implementation via legislative framework. Therefore, the analysis will deal with topological characteristics for a number of aspects by expressing the simple graph of the network in a matrix format. These aspects are simulated and measured through the matrices powering process and the principles of graph theory. However, in addition to reducing the time the vehicles stays on the road, the study results will assist to divert a large proportion of the traffic volumes concurrently with the implementation process, and this in turn will pave the way to precede the solution of the second phase inside the cities. Not to mention, the legislative framework will bases for the financial framework of the transport agency. Keywords: infrastructure inadequacy& development, accessibility and connectivity, graph theory, matrix representation &powering, new linkage, nodal accessibility , relative value ,optimum priorities (ranking) and Decision making(legislation).
Traffic accidents and traffic delay have a negative impact on the mobility traffic flow due to their huge costs on the transport system. Thus one of the main primary aims for transport policy makers are reducing the negative effect of traffic accidents and traffic delay on the road network. In this study, fixed and random parameters Tobit models have been developed to model the accident rates from 20 intersections in Al-Karakh district in Baghdad City, Iraq. The safety significant of logarithm of annual average daily traffic, the percentage of heavy vehicles and the delay time for both major and minordirections for each intersection on the accident rates were evaluated. The main finding of this study shows that delay has an important effect on traffic accident rates of intersections. Regarding to the effect of other factors on traffic Accident rates, the result of the model shows that the logarithm of annual average daily flow, the percentage of heavy vehicles for both major and minor directions of the intersection are positively associated with more accident rates.