certain letter is not promised. Under extreme load when too many letters arrive to the post office, the letters get delayed due to lack of resources.
On one hand, the best-effort policy is a good option to disseminate text data services across the network such as Email service and text messaging service. These services are categorized as delay tolerant, where in-time delivery of data is not so important. Even some data loss is bearable by these services to some extent given the context of the text is not violated. On the other hand, a best-effort network does not seem to comply with the requirements of multimedia service deliverance. Unlike textual services, multimedia services are known to be bandwidth hungry and delay in-tolerant by nature. Therefore, distribution of multimedia content over cellular networks requires some special treatment i.e., the underlying network must guarantee a certain level of constant data speed for a given multimedia session. Network over-provisioning to achieve this is the usual solution but not an economical one in this regard.
extent in comparison with the results measured from practical scenarios having the same inputs . Furthermore, the modeling is conducted for extreme worst-case parameters for both LTE and DVB-T systems. For example, out of band (OOB) emission mask for LTE UE is modeled without considering the actual reduction of OOB limits in the case of partial resource blocks assignment to UE. And a worst case ACS DVB-T receiver mask is representing the extreme protection ratios as provided by DTT community to cover all types of implemented DTT receiver (including obsolete ones).
❼ Session binding
❼ Address resolution of nodes
220.127.116.11 Fraunhofer FOKUS OpenIMS and OpenEPC testbed
FOKUS competence center NGNI and TU Berlin -AV established a cutting edge testbed system for 3GPP EPC known as the OpenEPC. It will assist not only the industry, but academic institutes (Universities, Research Centers etc.) as well in developing a real-world working scenarios of the 4G technology. The FOKUS team has provided number of updates for this test-bed and the version 4 from May 2013 is under consideration of this research. The interfaces provided in the version 4 have given support for a lot of different access technologies. The OpenEPC toolkit is thought to be one of the most advanced and customizable platform for the fundamental testing of functions of cellular networks . Testing of latest releases of cellular technologies like GSM, UMTS, HSPA and LTE is supported by OpenEPC. Following are some of the advantages of the available solutions as a result of the usage of OpenEPC along with 3GPP LTE Rel.11 :
in vivo testing strategy implies the use of
140 dams and 1,000 pups and is therefore extremely time- and cost-intensive (Lein et al. 2005). Relying solely on the existing guide- lines to address current and anticipated future regulatory demands for DNT of the thou- sands of chemicals for which there are few to no DNT data would incur unacceptable costs in terms of animals and person-years (Lein et al. 2007). Therefore, according to the “3R principle” (reduction, replacement, and reﬁne- ment) of Russel and Burch (1959), alternative testing strategies are needed to address ani- mal welfare by reﬁning and reducing animal experiments, and to create aﬀordable, sensi- tive, and mechanism-based methods suitable for high- or medium-throughput screening (Collins et al. 2008). Furthermore, the inclu- sion of human-cell–based in vitro systems into an integrated DNT tiered testing approach
culture in proliferation medium consisting of Dulbecco’s modified Eagle medium (DMEM) and Hams F12 (3:1) supplemented with B27 (Invitrogen GmbH, Karlsruhe, Germany), 20 ng/mL epidermal growth factor (EGF; Biosource, Karlsruhe, Germany), and 20 ng/ mL recombinant human fibro blast growth factor (FGF; R&D Systems, Wiesbaden- Nordenstadt, Germany) (Moors et al. 2007). When spheres reached 0.7 mm in diameter, they were chopped up to passage 3 with a McIlwain tissue chopper. Differentiation was initiated by growth factor withdrawal in dif- ferentiation medium [DMEM and Hams F12 (3:1) supplemented with N2 (insulin, transferrin, sodium selenite, putrescine, and progesterone; Invitrogen)] and plated onto poly-d-lysine/laminin–coated chamber slides (BD Bioscience, Erembodegem, Belgium).
On the one hand, the understanding of early evolution and especially its principles needs to be improved. The formation of the ﬁrst control struc- tures and how early coevolution between morphology and control emerged is one question. Investigating brain-body coevolution with such biologi- cally plausible models should gain deeper insights into the coevolution of nervous systems and morphologies in biology. The model designed here uses a biologically inspired encoding and should therefore provide the op- portunity to produce results that improve the understanding of biological evolution, but a direct comparison to biology is not an aim of this thesis. On the other hand, it should be possible for the proposed system to be used in engineering optimization e.g. to build robots or optimize the structure of a material. A major advantage of such models is that shape and control can be optimized concurrently, as described in Figure 1.1. Evolving morphology and control together in one genome, which is dif- ferent to most approaches in the literature is a major aim of this thesis. The possibility to evolve morphology and control together provides the opportunity that their complexity increases concurrently and therefore it could improve the optimization process. The tasks for the evolution in this thesis are examples, e.g. a neural network that controls food catching or performs movements for swimming. The individuals, which are artiﬁ- cial animals, are termed animats. In this thesis only simulations of the individuals are used, as building these robots in real hardware is beyond the scope of this thesis due to the additional complexity involved.
Consumption of mobile data traffic has been growing exponentially due to the pop- ularity of smartphones and tablets. As a result, mobile network operators have been facing challenges to provide needed capacity expansion in their congested network. Therefore to reduce the load on the network, mobile network operators are adapting and deploying key data offloading technologies such as femtocells not only to boost their network capacity but also to increase indoor cellular coverage. These low cost devices interconnect a new femtocell network architecture to evolving telecommu- nication core network via standardized interface protocols. However, consequences of such integration of two architectures over the Internet together with an array of security threats that originating through a rogue femtocell have not fully analysed. In this thesis, we investigate security architecture of femtocell-enabled cellular net- work that facilitate integration of these two architectures by evaluating impact of compromised femtocells on the fundamental security aspects of cellularsystems - integrity, confidentiality, authenticity, and availability.
The performance degradation of today’s cellular networks because of hot spots and the expected routing nature of future cellular networks make a case for a closer investi- gation of routing dependability issues. The dependability of existing cellularsystems sets a very high benchmark because of the closed network paradigm, the tight network con- trol and the ownership of infrastructure. Moreover, the related network performance aspects of dependability for this class of networks are of interest. In particular, we iden- tify two interesting research directions coupled with routing dependability in cellular networks. First, one main research direction in cellular networks is to optimize the utili- zation of the deployed infrastructure components. Our investigation aims at smarter sys- tems than available today. Novel network designs propose that the routing process starts at the edge of the network. This leaves room for optimization of the network perfor- mance; a smart cellular network may gain in network performance while maintaining the current level of dependability. This increase in performance can lead to an increase in perceived QoS from a user’s perspective and, thus, to an increase in perceived depend- ability. Second, possible dependability gains of cellular networks can be achieved by introducing a simplified and self-adaptive network control. While this does not necessar- ily increase the dependability of the network under normal conditions, it may allow for self-healing and self-organizing network operation, which includes the possibility of increased dependability in case of failure of the central network control components.
• nonlinear: in the quantities mentioned above appear products of variables, or variables raised to the second power or bigger, or any other mathematical operator that lays out the previous definition.
Linear systems theory is well developed because the superposition principle holds: a linear system can be divided into parts that are independent and as a consequence can be studied separately, the effects on the whole system being the sum of the single ones. Because of the superposition principle, such problems can often be broken into simpler pieces that can be solved individually, and then the results can be added together. The superposition principle does not hold for nonlinear systems, so many difficulties arise which prevent us from using tools developed in linear theory.
abelian groups of prime exponent p. Hence, we obtain examples of countably many distinct varieties which are closed under taking cellular covers. Some more studies on cellular covers of particular groups and of groups with speciﬁc additional properties have been conducted and can be found in a considerable amount of literature, see e.g. , , , , , , and . This area of
While much attention is focused on biochemistry for the design of artificial tis- sues, physical cues like topography, force or the mechanical properties of the environment might be equally important for cellular decision making. During recent years, rapid advances in materials science, including the development of microcontact printing, soft lithography, micro-fluidics and nano-technology, improved the control of cues in the micro-environment of adherent cells and thereby provided new tools to study the basic principles of cell organization and to design new artificial and biomimetic environments for cells. The de- velopment of technologies to control surface chemistry and topography has allowed to systematically study their effects on cell organization [21–23]. In contrast, the influence of substrate mechanics on cell organization has been appreciated by a wider community only very recently and much less is known about it. A systematic study of substrate elasticity on cell behavior requires new technologies to create substrates with well defined mechanics on micro- and mesoscale in combination with accurate measurement methods to quan- tify the local mechanical properties of the substrates on the microscale . Today, three materials are commonly used as model substrates to study the effects of substrate elasticity on cell organization: polyacrylamide (PAAM), polydimethylsiloxane (PDMS) and agarose gels. All materials are synthetic hydrogels and by adjusting the degree of cross-linking their mechanical proper- ties can be easily tuned within and beyond the physiologically relevant rigidity ranges of sub-kPa (nerve tissue) up to several MPa (pressurized arteries). In order to promote cell adhesion, the gel surfaces have to be modified, usually by covalent modification with specific ligands, since these surfaces usually are re- sistant to protein absorption from solution . This allows to vary mechanics independently from surface chemistry.
However, the legend used for the creation of the maps for the Moland project is, for this type of study, too detailed. It was considered a number of land uses reduced to the most significant twelve.
A further element, which is of extreme importance in the application of a cellular automaton, is the temporal step of the automaton itself. The lack of maps for the various cities referring to the same years induced the exploration of three different amplitudes, equal to 36, 40 and 42 months. Examining the number of months elapsed in each transition between maps of the various cities demonstrated how even in the case of new cities; the best choice was to consider the step of 36 months. This allows us to have a whole number of steps, or a difference of 1/3 of a step (over or under a whole number). Moreover, this choice allows us to remain consistent with the results obtained in above mentioned previous paper.
One remaining origin of the heterogeneity observed is the internal protein com- position of the cell. This aspect cannot be studied directly from the phenotypic read-outs of the data. The use of sister cell analysis has proven to be a helpful tool to analyse characteristics of signalling pathways [112, 319, 293]. The assumption is that sister cells are more similar in their molecular setup than a randomly picked pair of cells. Hence, to investigate the influence of the variable protein composi- tion of cells, recently divided cells were compared with randomly picked cells. The approach will show if the observed heterogeneity is due to stochastic fluctuations or based on the internal state of the cell, defined by the cellular molecular setup. Therefore, it could be assumed that heterogeneity is linked to the cellular state, if it could be shown that the signalling dynamics of sister cells are more similar over a longer period of time compared to dynamics of randomly selected cells. To make the analysis more sustained in addition ‘artificial sister cells’ are intro- duced. As ‘artificial sister cell’ cells, cells were labelled that coincidentally shared the same nuc/cyt SMAD2 ratio at a certain time point (‘artificial divisions’). These set was used to exclude that the observed effect for sister cells is not just due to the same ratio at the moment of division.
THE DIVERSITY OF ORGANELLAR PEPTIDE TRANSPORTERS
Different classes of peptide transporters have evolved (Figure 1). All in common is a high substrate promiscuity. Peptides containing two to eight residues are transported by members belonging to the oligopeptide transporter and peptide transporter family ( Gomolplitinant and Saier, 2011; Newstead, 2015 ). Both families belong to the Major Facilitator Superfamily of secondary active transporters, which are proton-dependent transport systems. Oligopeptide transporters, translocating peptides of three to eight amino acids in length, are found in bacteria, plants, and fungi. Di- and tripeptide transporters are also present in animals. Human PepT1 and PepT2 are found in the brush border membrane of the small intestine and at the renal epithelium in the kidney, respectively. Both transporters absorb or retain protein fragments in the body. Interestingly, PepT1 is the fast, low-affinity transporter while PepT2 shows slower transport rates paired with higher affinity ( Brandsch, 2013 ).
constant velocity needs to be added on top of the mechanism that balances out the density gradient in the system. Intriguingly, we find both contributions to be on the same order of magnitude. The underlying mechanism that leads to this macroscopic drift remains unclear. It seems plausible, however, that it could be the same mechanism responsible for the spontaneous occurrence of collective rotation observed in disc-like systems [60, 142], where due to the circular geometry there are no front or back edges, and hence no density gradients. Here, the most likely candidate leading to the rotation is polarization of the cells along the symmetry breaking boundary conditions. The outermost cells do not have an equal probability of polarizing in all directions and thus are more likely to polarize along the boundary. This polarization is then passed on to neighboring cells up to one correlation length, as indicated by the fact that for very large discs, Doxzen et al. observe a breakdown of collective rotation . Transferring this idea to our channel system, symmetry is broken by the boundary walls, thus cells immediately adjacent to them have an increased probability to polarize parallel to the direction of migration. Possibly, the fact that there is already a preferential migration direction present due to balancing out the density gradient further biases the preferential polarization direction to align towards the cell front and away from the bulk. This polarization is then again passed on to neighboring cells as far as one correlation length. In our case, with a measured correlation length on the order of 100 µm, and polarization stemming from two opposing walls, this would imply that this polarization mechanism works well up to channel widths of 200 µm, close to the greatest width of 300 µm used in our experiments. For significantly larger channel widths, up to the limit case of unconfined cell sheets such as in wound healing assays, the contribution of a biased polarization might vanish. This could explain why in such cases, people have found the Fisher-Kolmogorov equation to be an adequate description [149– 151] within the accuracy of their measurements. On the other hand, it cannot be ruled out that the confinement by neighboring cells on the side is sufficient to reduce likelihood of polarization in that direction. In this case, polarization would not necessarily be induced by the walls but rather by the fact that cells at the leading edge would have a higher probability of polarizing towards the open area, where they are not confined. Again, this polarization could then couple across multiple cell layers into the sheet. Correspondingly, cells in an expanding monolayer would then be expected to move just as fast as those confined by walls.
GPI-anchored protein such as PrP c is surprising because PrP c has no cytoplasmic domain that can interact directly with the intracellular components of coated pits (Harris, 1999). Here a receptor protein could be responsible for making the connection between the surface-anchored PrP to clathrin. The uptake of PrP Sc is thought to be mediated directly by a receptor protein such as LRP, but could also be mediated in an indirect manner dependent on the presence of cellular PrP. We assume that internalized PrP Sc interacts with PrP c during the endocytic pathway (Fig. 3). PrP c is probably converted into PrP Sc within the endosome, lysosomes or endolysosome influenced by an unknown protein termed protein X (Telling et al., 1995) which could represent a molecular chaperone such as Hsp60 (Edenhofer et al., 1996). Recently, a homology of the amino terminus of LRP with members of the Hsp70 family was observed (Ardini et al., 1998) suggesting that LRP/p40 might be involved in protein folding. Although we demonstrated a specific interaction between PrP and members of the Hsp60 family including GroEL (Edenhofer et al., 1996), no binding of PrP to members of the Hsp70 family was observed, which suggest no homology to the Hsp60 family (Edenhofer et al., 1996). However, it cannot be excluded that a hypothetical chaperone activity of LRP might be involved in the PrP c /PrP Sc conversion reaction, which is thought to occur in endosomes, lysosomes or endolysosomes of the endocytic pathway in the life cycle of prions. Other proteins encompassing an GPI-anchor were internalized by caveolae (Anderson, 1993). It has been suggested that PrP c and PrP Sc are internalized by CLDs, a compartment where the conversion of PrP c to PrP Sc might also take place (Vey et al., 1996). PrP Sc accumulation leads to neuronal cell death resulting in vacuolization and death of the organism.
Boolean Network (BN) has been analyzed through long term as one of discrete dynamical systems, and it has yielded many results about the model [6, 4]. The BN is the system which consists of the set of Boolean variables which are determined in each discrete time step depending on other Boolean variables of the system. The Random Boolean Network (RBN) which is also called as the N-K model or the Kauffman Network, is a particular model of the Boolean network. Triggered by the epoch-making work of Kauffman , the properties of various realizations of RBNs have been investigated. At- tracted properties of RBNs are, the number of attractors, the length of attractor’s cycle, the size of basin of attractors, transient time (the number of steps the system takes before it falls into an attractor), and properties about stability against perturbations and mutations. Since the dynamic NWFG model can be treated as one of the discrete dynamics systems, we presume that it is effective to apply approaches for analyzing BNs as the method of the analysis of the state space of the dynamic NWFG model.
thy threats to the availability of cellular network systems [ 54 , 105 , 116 ]. Femtocells support radio signaling and communication with back-end networks by design. The femtocell exchanges signaling messages with architectural components such as VLR, HLR, AuC, and SGSN via the HNB-GW to ofer mobile services to subscribers. Therefore they also provide potential for abusing this functionality to perform sig- naling attacks. As described in Section 3.3.3, it is possible to send malicious traic to the HNB-GW from the femtocell, using our attack client and the GAN proxy. This indicates that if such a device is compromised and conigured maliciously by an attacker, it can be used to carry out signaling attacks against classical CN compo- nents. While the gateway might apply rate iltering rules, the femtocell is intended to be used by multiple subscribers and thus provides an advantage compared to using a malicious mobile phone for such attacks. Furthermore, the femtocell is com- municating via a broadband connection with the back-end and is not subject to additional constraints caused by radio communication (e.g., frequency stability and synchronization). Therefore, it can be used to inject signaling traic into a net- work protocol basis at a comparably high rate. A reasonable threat is to use the presented GAN protocol to lood the network with Location Update Requests that include diferent IMSI numbers for each request [ 116 ]. As a result, it might be pos- sible to considerably increase the load of the network because it has to generate and store authentication tokens as well as keeping state of these requests. Sending these requests can be performed without any mobile phone and can be automated using the aforementioned attack client to generate the corresponding L3 messages.
This idea raised the question which cellular functions might be impaired by a surplus of Ufe1. The finding that overexpression of a Sly1 interaction-deficient ufe1 mutant is less toxic than WT UFE1 suggested that overexpression might affect specific cellular functions that particularly rely on Sly1. Thus, an excess of Ufe1 might result in the titra- tion of the available cellular pool of Sly1 that normally is engaged with other partners, e.g. Sed5, which is also essential for viability. Reciprocally, overproduced Sed5 would be equally expected to interfere with the essential functions of Ufe1. Indeed, overex- pression of SED5 caused an even stronger cytotoxic effect (Figure 2-17), probably since Sed5 is intrinsically stable and cannot be proteolytically down-regulated contrary to Ufe1. Intriguingly, concomitant overexpression of UFE1 but not of the Sly1 interac- tion-deficient ufe1 mutant reduced the growth defect caused by the surplus of Sed5 (Figure 2-17). Likewise, the Sed5-mediated cytotoxicity could be compensated directly by overexpression of SLY1 (data not shown). Since both SNAREs reside in different compartment – Ufe1 in the ER, Sed5 in the Golgi apparatus – it is unlikely that they in- teract directly with each other. Instead the attractive possibility could be envisaged that Ufe1 and Sed5 might communicate via a competition for available cellular pools of Sly1. This would provide an elegant mechanism by which both SNARE proteins and their re- spective vesicle fusion processes could be reciprocally regulated. However, whereas superfluous Ufe1 is disposed by ERAD, a similar mechanism does not seem to exist for Sed5.