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Conservation work on cultural heritage occurs mostly ‘behind the scenes’, hidden away from the general public. Research has shown, however, that there is considerable interest from tourists and locals alike to gain insights into conservation practice. While this can be done through visits to conservation laboratories or heritage sites, an additional tool to complement these visits is to provide documentary films of ongoing conservation work.
In the summer of 2016, a group of international master’s students from different study programmes at Brandenburg University of Technology Cottbus-Senftenberg visited Florence to study issues related to the preservation of cultural heritage. In particular, they examined conservation-related work being done at the Courtyard of Michelozzo in the Palazzo Vecchio, where Giorgio Vasari originally decorated the upper wall sections and ceiling with frescoes in 1565. Due to daily wear and tear, which has been exacerbated by a high number of visitors as well as climatic conditions, conservation work became necessary to address soiled painted surfaces, disintegrating plaster and missing sections of the plaster and paint layers.
This collection of papers addresses a variety of topics relating to the wall paintings by Vasari, as well as threats and tools to protect and conserve them and other cultural heritage sites that are faced with growing tourism. This student project was carried out in collaboration with the UNESCO Office of the Municipality of Florence (Carlo Francini and Chiara Bocchio), the Fine Arts Department of the Municipality of Florence (Giorgio Caselli), the director of the conservation work (Fabio Sforzi), wall painting conservators of the Vasari frescoes (Cristina Conti and Alessandra Popple), the Department of Architectural Conservation at Università di Firenze (Giuseppe Centauri and Daniela Chiesi) and the BTU Media Centre (Ralf Schuster).
Tanzania is the land which has extensive Limestone Caves along the Swahili Coast of East Africa. Many of these Limestone Caves believed to be formed about 150 million years ago during the Jurassic age when these areas were underwater. For a long time, Swahili communities along the coast of East Africa used the Limestone Caves as the places of worship, praying and conducting ritual practices. These Limestone Caves have been regarded as the Mosques, Churches or Temples by these Swahili communities who have been associated with the Caves for a long time before colonial time in 17th-19th Century. After independence in 1961, the Tanzanian government took over many of the Limestone Caves to manage and protect them as the national heritage under the Antiquities Divisions and other heritage governing bodies. However, in Tanzania the protection of Limestone Caves as Sacred Heritage Places have been only through modern laws which were inherited from colonial masters and are yet to produce satisfactory results on the best practice of these places, even after amendments. Other problems facing Sacred Heritage Places in Tanzania are lack of management plans, lack of freedom in worship and failure of Antiquities legislation to recognise traditional beliefs. These problems led to growing concern of different stakeholders regarding the government strategy to ensure prescriptions for best practices of the Sacred Heritage Places in Limestone Cave areas regarding the use, management and conservation.
Therefore, the purpose of this thesis is to examine the use and management of Sacred Heritage Places along the Swahili Coast of the Indian Ocean in Tanzania. Data were obtained through focus group discussions, interviews and observations while legal documents were reviewed and analysed using thematic analysis to investigate research themes. The results indicated that there were ritual practices, strict taboos and customary laws used to control access into the Limestone Cave area but tourism and research activities have interfered with the sacred space creating a disconnect between the local communities and their heritage. This disconnection has driven people from their traditional religions into religions like Christianity and Islam.
Finally, the thesis proposes MTRCC Framework for a heritage plan for best practice in Sacred Heritage Place in Limestone Cave areas; to be adopted by the Tanzanian Antiquities Divisions and other heritage management authorities to ensure that local communities have access to spaces crucial to their religious life. Also, MTRCC Framework ensures that there are no conflicts or
interference from tourism, education and research activities that could result in negative effects for the heritage sites and stakeholders can have equal opportunities to experience these places.
From Gleason's theorem we know that in principle every probability measure can be expressed by Hermitian operators in a separable Hilbert space and the Born rule as part of a quantum mechanical system. However, that theorem is not constructive. For a given discrete and additive probability measure based on a σ-algebra we construct a quantum system with projectors expressing that probability measure.
The strive for performance, low power consumption, and less chip area have been diminishing the reliability and the time to fault occurrences due to wear out of electronic devices. Recent research has shown that functional units within processors usually execute a different amount of operations when running programs. Therefore, these units present different individual wear out during their lifetime. Most existent schemes for re-configuration of processors due to fault detection and other processor parameters are done at the level of cores which is a costly way to achieve redundancy. This paper presents a low latency (approximately 1 clock cycle) software controlled mechanism to reconfigure units within processor cores according to predefined parameters. Such reconfiguration capability delivers features like wear out balance of processor functional units, configuration of units according to the criticality of tasks running on an operating system and configurations to gain in performance (e.g. parallel execution) when possible. The focus of this paper is to show the implemented low latency reconfiguration mechanism and highlight its possible main features.
Scaling minimum features of ICs down to the 10nm- area and below has allowed high integration rates in electronics. Scaling at supply voltages of 1V and below also implies a rising level of stress which drives aging effects that reduce switching speed and the expected life time. Additionally, vulnerability from particle radiation is increased. Hence, fault detection and on-line correction become a must for many applications. However, not only fault tolerance but self-awareness becomes also an advantage. Provided that by being aware of its own healthy state allow optimized configurations regarding system operation modes and configurable hardware mechanism. This paper shows a preliminary work in a configurable circuit and explores its configuration possibilities when integrated into a complete system.
We consider two mathematical problems that are connected and occur in the layer-wise production process of a workpiece using Wire-Arc Additive Manufacturing. As the first task, we consider the automatic construction of a honeycomb structure, given the boundary of a shape of interest. In doing this we employ Lloyd’s algorithm in two different realizations. For computing the incorporated Voronoi tesselation we consider the use of a Delaunay triangulation or alternatively, the eikonal equation. We compare and modify these approaches with the aim of combining their respective advantages.
Then in the second task, to find an optimal tool path guaranteeing minimal production time and high quality of the workpiece, a mixed-integer linear programming problem is derived. The model takes thermal conduction and radiation during the process into account and aims to minimize temperature gradients inside the material. Its solvability for standard mixed-integer solvers is demonstrated on several test-instances. The results are compared with manufactured workpieces.
Planning the construction of new transport routes or power lines on terrain is usually carried out manually by engineers, with no guarantee of optimality. We introduce a new approach for the computation of an optimal trajectory for the construction of new transit routes and power lines between two locations on a submanifold U _ R3 representing the topography of a terrain. U is approximatively modeled by a special weighted grid. On this grid, the shortest paths for the construction of new routes are determined, whereby we consider three optimization criteria: routes with minimum distance, routes with lowest construction costs and routes with minimum absolute altitude variations or minimum absolute gradients. Subsequently, a combination of these criteria is used to expand this problem into a multi-criteria optimization problem. A shortest path algorithm, such as the Dijkstra algorithm, is used to compute optimal compromises for the construction of new routes.
In this work, we consider non-reversible multi-scale stochastic processes, described by stochastic differential equations, for which we review theory on the convergence behaviour to equilibrium and mean first exit times. Relations between these time scales for non-reversible processes are established, and, by resorting to a control theoretic formulation of the large deviations action functional, even the consideration of hypo-elliptic processes is permitted. The convergence behaviour of the processes is studied in a lot of detail, in particular with respect to initial conditions and temperature. Moreover, the behaviour of the conditional and marginal distributions during the relaxation phase is monitored and discussed as we encounter unexpected behaviour. In the end, this results in the proposal of a data-based partitioning into slow and fast degrees of freedom. In addition, recently proposed techniques promising accelerated convergence to equilibrium are examined and a connection to appropriate model reduction approaches is made. For specific examples this leads to either an interesting alternative formulation of the acceleration procedure or structural insight into the acceleration mechanism. For the model order reduction technique of effective dynamics, which uses conditional expectations, error bounds for non-reversible slow-fast stochastic processes are obtained. A comparison with the reduction method of averaging is undertaken, which, for non-reversible processes, possibly yields different reduced equations. For Ornstein-Uhlenbeck processes sufficient conditions are derived for the two methods (effective dynamics and averaging) to agree in the infinite time scale separation regime. Additionally, we provide oblique projections which allow for the sampling of conditional distributions of non-reversible Ornstein-Uhlenbeck processes.
We present a general numerical solution method for control problems with PDE-defined state variables over a finite set of binary or continuous control variables. We show empirically that a naive approach that applies a numerical discretization scheme to the PDEs (and if necessary a linearization scheme) to derive constraints for a mixed-integer linear program (MILP) leads to systems that are too large to be solved with state-of-the-art solvers for MILPs, especially if we desire an accurate approximation of the state variables. Our framework comprises two techniques to mitigate the rise of computation times with increasing discretization level parameters:
First, the linear system is solved for a basis of the control space in a preprocessing step. Second, certain constraints are just imposed on demand via the IBM ILOG CPLEX feature of a lazy constraint callback. These techniques are compared with an approach where the relations obtained by the discretization of the continuous constraints are directly included in the MILP. We demonstrate our approach on two examples: modeling of the spread of wildfire and the mitigation of water contamination. In both examples the computational results demonstrate that the solution time is significantly reduced by our methods. In particular, the dependence of the computation time on the size of the spatial discretization of the PDE is significantly reduced.
Annealing-induced solid phase crystallization of In₂O₃:H leads to a significantly improved electron mobility, which is confirmed by Hall measurements. Indium hydroxide dehydroxylation occurs in In₂O₃:H during annealing, which is well responsible for the structural transformation and a high electron mobility with a decreased carrier concentration in crystallized In₂O₃:H. A significant decrease in the intensity of occupied gap states is observed in crystallized In₂O₃:H, possibly due to a decrease in carrier concentration. Doped In₂O₃ variants have been found to have a quite deeper allowed transition level below the valence-band edge than undoped In₂O₃, which in particular applies to crystallized In₂O₃:H, but most likely attributed to a change of the crystal structure upon annealing and/or a different O 2p-In 4d coupling near the VBM compared to amorphous In₂O₃:H.
To well understand the interface properties of Ag/In₂O₃:H upon annealing, a thin Ag film was grown on the In₂O₃:H substrate and annealed in vacuum up to 300 °C. During annealing, the potential Ag diffusion into the bulk In₂O₃:H and/or a change of an annealing-induced Ag topography (i.e., cluster formation) occurs, with a small Ag oxidation (i.e., Ag₂O and AgO). With Ag deposition, an initial downward band bending of (0.11±0.05) eV was present in In₂O₃:H, attributed to a Schottky contact formed at the Ag/In₂O₃:H interface. Upon annealing, the downward band bending reduces gradually, and the Schottky-barrier height at the Ag/In₂O₃:H interface also decreases.
A thickness series of the individual materials on the respective “substrate” (i.e., MnS/Si, GaN/MnS, and ZnO/GaN) was epitaxially grown on Si (100) wafer, and the interfacial chemistry and energy-level alignment at the respective interfaces are examined using photoelectron spectroscopy. At the MnS/Si interface, an interface-induced band bending (IIBB) appears in Si, which of values are found to be (0.15±0.07) and (0.23±0.07) eV for 4 and 15 nm MnS/Si stacks, respectively. The MnS/Si heterointerface shows a type-II (staggered) band lineup with a VBO of (-0.37±0.10) eV and the corresponding CBO of (2.27±0.10) eV. For the GaN/MnS interface, a significant diffusion of Mn into the GaN layer takes place during GaN deposition. In addition, an interface-induced band bending (IIBB) by ~0.30 eV is observed in MnS. The GaN/MnS interface shows a type-II (staggered) band lineup with a VBO of (1.46±0.10) eV and the corresponding CBO of (-1.09±0.10) eV. At the ZnO/GaN interface, a significant N diffusion from GaN into ZsnO takes place, i.e., Zn-N bonds, when ZnO is grown on the GaN layer. Also, an interfacial oxide (GaOx) layer was formed during ZnO deposited on GaN films. The ZnO/GaN heterointerface shows a type-II (staggered) band lineup with a VBO of (2.48±0.10) eV and the corresponding CBO of (-2.50±0.10) eV, respectively.