Security Issues in Mobile Database Access

Mobile computing and communication is a rapidly developing area. But mobility is associated with problems for security and privacy beyond those in open networks. A well known threat is tracking user movements. New risks are caused by the mobility of users, the portability of computers, and wireless links which include dynamics, resource dependencies and additional information to ensure the communication. This paper surveys the new challenges and the research on security issues in mobile data management, access and transfer. We investigate the issues concerning database specific security which have to be reconsidered. We will identify a basic characteristic of these security issues, adaptability, to answer the dynamics. 1 Introduction The development of mobile devices make new applications conceivable through ubiquitous computing. For example, mobile work "on-the-spot" like disaster recovery and maintenance tasks as well as business trips are possible. Mobile computing and communicati..

Transfer reactions in Pb 206 + Sn 118: From quasielastic to deep-inelastic processes

We measured multinucleon transfer reactions for the Pb206+Sn118 system at Elab=1200 MeV by employing the large solid angle magnetic spectrometer PRISMA. Differential and total cross sections and Q-value distributions have been obtained for a variety of neutron and proton pick-up and stripping channels. The Q-value distributions show how the quasielastic and deep inelastic processes depend on the mass and charge of the transfer products. The corresponding cross sections have been compared with calculations performed with the grazing code. An overall good agreement is found for most of the few nucleon transfer channels. The underestimation of the data for channels involving a large number of transferred nucleons indicates that more complicated processes populate the given isotopes

Study of the quasi-free 3He+9Be→3α reaction for the Trojan Horse Method

A new study of the quasi-free contribution to the 3He+9Be→3α reaction (Q value = 19.004 MeV) at low E3He energy is presented. The reaction was studied in a kinematically complete experiment at beam energy of 4 MeV. To clarify the presence of the quasi-free mechanism, the 4He –5He momentum distribution of the 9Be ground state was extracted. Standard tests were also carried out to confirm the presence of the quasi-free contribution and are reported in this work. The full width at half maximum of the 4He –5He inter-cluster momentum distribution inside 9Be was measured with improved accuracy, by adopting several different approaches that all led to consistent results. These preliminary investigations on the reaction mechanism are fundamental for future studies employing the Trojan Horse Method, with the 5He unbound nucleus as a virtual projectile

The 3 He+ 5 He → α + α reaction below the Coulomb barrier via the Trojan Horse Method

For the first time in an application to nuclear astrophysics, a process induced by the unstable 5He = (4He-n) nucleus, the 3He+5He→ 2α reaction, has been studied through the Trojan Horse Method (THM). For that purpose, the quasi-free (QF) contribution of the 9Be(3He,αα)4He reaction was selected at E3He=4 MeV incident energy. The reaction was studied in a kinematically complete experiment following a recent publication (Spitaleri et al. in Eur Phys J A 56:18, 2020), where for the quasi free contribution the momentum distribution between α and 5He particle cluster in the 9Be nucleus in the ground state have been extracted. The angular distribution of the QF 3He+5He→ 2α reaction was measured at θcm = 78∘–115∘. The energy dependence of the differential cross section of the 3He+5He→ 2α virtual reaction was extracted in the energy range Ecm = 0–650 keV. The total cross section obtained from the Trojan-horse method was normalized to absolute cross sections from a theoretical calculation in the energy range Ecm =300–620 keV

The 12^{12}C + 16^{16}O fusion reaction in carbon burning: Study at energies of astrophysical interest using the Trojan Horse Method

International audienceThe carbon-burning process in massive stars mainly occurs via the 12C +12 C. However, at temperatures higher than 109K and considering the increased abundance of 16O produced during the later stages of the heliumburning,the 12C+16O fusion can also become relevant. Moreover, 12C+16O also plays a role in the scenario of explosive carbon burning. Thus, the astrophysical energy region of interest ranges from 3 to 7.2 MeV in the center-of-mass frame. However, the various measurements of the cross-section available in the literature stop around 4 MeV, making extrapolation necessary. To solve this uncertainty and corroborate direct measurement we applied the Trojan Horse Method to three-body processes 16O(14N, α24Mg)2H and 16O(14N, p27Al)2H to study the 12C(16O, α)24Mg and 12C(16O, p)27Al reactions in their entire energy region of astrophysical interest. In this contribution, after briefly describing the method used, the experiment and the preliminary phases of the data analysis will be presented and discussed

Study of the 12C + 16O fusion via the Trojan Horse Method

The 12C + 16O fusion reaction plays a role in the later stages of carbon burning, influencing the evolution of both massive stars and Type Ia Supernovae: when most of the carbon is depleted, by the main fusion reaction 12C + 12C, the abundance of 16O nuclei is significantly higher. Therefore 12C + 16O can indeed have a strong impact on the process. In this brief contribution, preliminary data analysis results of a new indirect measurement of the 12C + 16O, performed at astrophysical energies via the Trojan Horse Method, will be presented and discussed

Study of the 12^{12}C + 16^{16}O fusion via the Trojan Horse Method

International audienceThe 12C + 16O fusion reaction plays a role in the later stages of carbon burning, influencing the evolution of both massive stars and Type Ia Supernovae: when most of the carbon is depleted, by the main fusion reaction 12C + 12C, the abundance of 16O nuclei is significantly higher. Therefore 12C + 16O can indeed have a strong impact on the process. In this brief contribution, preliminary data analysis results of a new indirect measurement of the 12C + 16O, performed at astrophysical energies via the Trojan Horse Method, will be presented and discussed

Study of the

12C +12 C is the main reaction during core and shell carbon burning in massive stars, however, at temperatures higher than 109K when most of the carbon is depleted and its abundance is lower than 16O, the 12C +16 O fusion can also become relevant. Moreover, 12C +16 O reaction can ignite also in the scenario of explosive carbon burning. The astrophysical energy region of interest thus ranges from 3 to 7.2 MeV in the center-of-mass frame. There are various measurements of the cross-section available in the literature, however, they all stop around 4 MeV, making extrapolation necessary at lower energies. To try to solve this uncertainty and corroborate direct measurement the Trojan Horse Method was applied to three-body processes 16O(14N, α24Mg)2H and 16O(14N, p27Al)2H to study the 16O(12C, α)24Mg and 16O(12C, p)27Al reactions

Study of the 12^{12}C +16^{16}O fusion reaction in carbon burning via the Trojan Horse Method

International audience12C +12 C is the main reaction during core and shell carbon burning in massive stars, however, at temperatures higher than 109K when most of the carbon is depleted and its abundance is lower than 16O, the 12C +16 O fusion can also become relevant. Moreover, 12C +16 O reaction can ignite also in the scenario of explosive carbon burning. The astrophysical energy region of interest thus ranges from 3 to 7.2 MeV in the center-of-mass frame. There are various measurements of the cross-section available in the literature, however, they all stop around 4 MeV, making extrapolation necessary at lower energies. To try to solve this uncertainty and corroborate direct measurement the Trojan Horse Method was applied to three-body processes 16O(14N, α24Mg)2H and 16O(14N, p27Al)2H to study the 16O(12C, α)24Mg and 16O(12C, p)27Al reactions