This thesis describes two proposed schemes that could be used to secure mobile messaging (SMS/MMS) as well as one scheme that could be used to secure mobile content. The security services we considered in securing the mobile messages are confidentiality, authentication, non-repudiation and integrity. We used Identity Based Cryptography in order to secure the mobile messaging and Blowfish algori...

Sternwarte der Universität Bonn, Auf dem Hügel 71, D -53121 Bonn Ph.D. degree awarded on 13. November 2001 Supershells with diameters larger than 300 pc need gigantic energy amounts of > 1053 erg for their formation. Since they are visible in all irregular galaxies as contiguous shells in H I and Hα, the question about their creation mechanism arises. Photometric studies in UBV passbands in bot...

Long-run cross-country price data exhibit a puzzle. Today, richer countries exhibit higher price levels than poorer countries, a stylized fact usually attributed to the “BalassaSamuelson” effect. But looking back fifty years, or more, this effect virtually disappears from the data. What is often assumed to be a universal property is actually quite specific to recent times. What might explain th...

A substantial part of the economic growth literature suggests that historically, geographic features such as decreasing trade costs have not only enhanced output, but may also be associated with rapid urbanization and ’growth take-offs’. However, this literature lacks an analytical motivation for lower transport costs, and assumes their decrease to obtain exogenously and at no cost: It thus doe...

Middle (10-50 ms) and long (50-600 ms) latency auditory evoked potentials (AEPs) were investigated in artificially respired, muscle-paralyzed cats. Similarity to human potentials of comparable latencies was examined in two ways: (1) the similarity of waveform features such as peak amplitude, polarity and latency, and (2) the effects of task-related variables on these various waveform features. ...

Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene plio-quaternary volcanic rocks with variable mineralogy geochemistry dominate geology this region. The presence active faults in different directions explains high tectonic instability frequency earthquakes. This study contributes effort understanding geothermal potential Northeast Morocco. H...

Natural discontinuities as well mechanical properties are the difficult-to-control parameters that significantly influence fragmentation of marble after blasting. In Central Africa, Bidzar quarry is only one producing marble, plagued for decades by block problems, requiring multiple blasts cause huge costs and environmental problems. The objective this study to predict rock improve its geologic...

In Cameroon in general and the Highlands of Cameroon particular, there is no fracture map since its realization not easy. The region’s harsh accessibility climatic conditions make it difficult to carry out geological prospecting field missions that require large investments. This study proposes a semi-automatic lineament mapping approach to facilitate elaboration of West Highlands. It use...