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Abstract:Location management is an essential process in future mobile communication networks. An important issue is an efficient management of the location database. In this paper, the next generation mobile communication networks are proposed to integrate with a TINA-compliant architecture enabling to handle that kind of mobile-specific processes. We consider a distributed location database architecture for location management performing the following strategies: HI.D (home location database only), HLD-VLD (HLD with a visited location database), or VLD-CLD (HLD and VLD with a cache location database). TIris paper discusses design, modelling and the comparison of the mentioned distributed location management strategies. The performance measures used for comparison are communication cost (signalling messages), computational cost (database accesses) and average total cost. For the performance analysis, we assume that the cost of updating a cache pointer and a user profile at CLDIVLD is equal. Results show that the combination of replication with caching scheme (VLD-CLD) performs better than the replication scheme (HLD-VLD) for a very wide range of call-to-mobility ratio (CMR).

Location management is an essential process in future mobile communication networks. An important issue is an efficient management of the location database. In this paper, the next generation mobile communication network is proposed to be integrated with a TINA-compliant architecture enabled to handle that kind of mobile-specific processes. This paper discusses the design, and its modeling and comparison of distributed location management strategies based on a TINA-compliant architecture for wireless mobile communication networks. A new location strategy called user profile replication with caching (UPRC) is proposed. In UPRC, user profiles based on user mobility patterns are replicated and combined with caching of the called user profile. This reduces the communication (signaling messages) and computational cost (database accesses) as compared to the location management schemes of simple replication with caching (SRC). A most frequent location area (MFLA) is then introduced which also reduces the number of location update messages between the home location database (HLD) and the visited location database (VLD) in such a way that the location change is reported to the MFLA of the user instead of the HLD. With the MFLA concept, the currently centralized location database becomes a distributed location database taking into account user mobility behavior. The unified performance measures used for comparison are communication costs, computational costs and average total costs.

In this study, the kinetics of the Fischer-Tropsch process (also known as FTS) were investigated using feedstocks produced from biogas. For the kinetic testing, a differential fixed-bed reactor was utilized to operate the Ni/Al2O3 catalyst produced using precipitation procedures. Experiments were carried out with a variety of settings for the working circumstances, such as reaction temperatures ranging from 543 to 563 °K, H2:CO ratios ranging from 0.5 to 3, a pressure of 3.0 megapascals, with (GHSV) a gas hourly space velocity of 3500 (1/h). The reaction kinetics within this range of conditions can be modelled in a precise and accurate way thanks to the derived kinetic parameters. The FT reaction hypothesized mechanism uses the Langmuir-Hinshelwood-Hougen-Watson theory, which predicts that carbon monoxide and hydrogen will have an adsorption behaviour. The kinetic data obtained in this investigation were effectively modelled using a straightforward equation, which is as follows: \({- r}_{CO}=\frac{k.{P}_{CO}^{n}.{P}_{{H}_{2}}^{m}}{{(1+K.({a}_{CO}.{P}_{CO}^{n}+{a}_{{H}_{2}}.{P}_{{H}_{2}}^{m})}^{2}}.\) This model implies that essential kinetic processes, such as CO dissociation by contact with adsorbed hydrogen, have already occurred. The first stage in the hydrogenation process is presumed to be fast and reversible, whereas the second step is presumed to be sluggish and rate-determining.