378 research outputs found
Fritz Schumacher & Heinrich Tessenow: Architecture, an Art or a Craft?
No full textThis booklet contains the inaugural lectures of Fritz Schumacher and Heinrich Tessenow given on the occasion of their appointment respectively as professors at the Technical University in Dresden and The Art Academy in Dresden.The lectures provide novel insights into their understanding of architecture and into their proposals for reform of architectural education. they are proceeded by an introductory essay of the guest editor architectural historian Hartmut Frank.History, Form & Aesthetic
Sociedades modernas, sociedades de obsolescência: a sociologia temporal de Hartmut Rosa / Modern societies, obsolescence societies: Hartmut Rosa's temporal sociology
No full textResenha de: ROSA, Hartmut. Aceleração: a transformação das estruturas temporais na modernidade. São Paulo: Editora Unesp, 2019. Centrado na revisitação da modernidade a partir de uma perspectiva temporal, Hartmut Rosa sustenta o conceito de aceleração social como aspecto fundante do projeto moderno. Explorando diferentes variáveis causais para o conceito da aceleração social, a resenha examina as transformações das instituições morais, valorativas e políticas ocorridas ao longo do desenvolvimento histórico da modernidade como episódios induzidos pela obsolescência. Sendo esta um produto de campos de ação crescentemente cambiantes e acelerados, o autor mobiliza esse conceito para fundamentar inédita proposta de diferenciação entre a modernidade e a modernidade tardia como momentos históricos calcados em diferentes níveis de compressão espaço-temporal, estabilidade institucional e temporalização de projetos individuais e coletivos de futuro.***AbstractCentered on revisiting modernity from a temporal perspective, Hartmut Rosa supports the concept of social acceleration as a fundamental aspect of the modern project. Exploring different causal variables for the concept of social acceleration, the review examines the transformations of moral, valuative and political institutions that occurred during the historical development of modernity as episodes induced by obsolescence. As this is a product of increasingly changing and accelerated fields of action, the author mobilizes this concept to substantiate an unprecedented proposal for differentiation between modernity and late modernity as historical moments based on different levels of space-time compression, institutional stability and temporalization of individual and collective future projects
Surveying silk fibre degradation by crystallinity determination: a study on the Tang-Dynasty silk treasure from Famen Temple, China
No full textWhen Chinese archaeologists opened an unknown vault under the collapsed pagoda of Famen Temple near Xian (Shaanxi Province, NW China) in 1987, they found a vast amount of valuable silk textiles. The degraded textiles were part of a treasure comprising hundreds of artifacts deposited by Tang dynasty (ad 618–907) emperors as a gift to the temple. Run as a bilateral German-Chinese project, the Roemisch-Germanisches Zentralmuseum Mainz established a textile conservation laboratory in Shaanxi´s provincial capital Xian in 2001, joining numerous other laboratories that have existed there since the early 1990s.This preliminary study represents part of an ongoing investigation programme that accompanies the conservation work. The Tang dynasty silk is generally in a very poor state of preservation as a result of its long burial period. Large sections have only survived as an amorphous brown mass of fibre debris. Some parts are better preserved, however, offering the unique opportunity to study the whole range of degradation stages on ancient silks.This preliminary scientific investigation focuses on the determination of the silk fibres’ crystallinity and its relation to the ageing process. As we know from modern material, silk is mainly crystalline, albeit in a somewhat amorphous state. The methods of investigation used were X-ray diffraction (XRD) using synchrotron radiation, which is a new way to determine crystallinity of ancient silk fibres; and polarized Fourier transform infrared spectroscopy (FTIR) for the determination of crystallite orientation. Both methods were specifically devised to gain information on small single fibres
Binary classification with adiabatic quantum optimization
No full textWe study the problem of supervised binary classification from the perspective of deploying adiabatic quantum optimization in training. A vast body of prior academic work consisting of both theoretical and numerical studies has indicated that quantum technology promises to provide computational power that may be fundamentally superior to any classical computing methods. Given the abundance of NP-hard optimization problems that naturally arise in learning, it is clear that machine learning can immensely benefit from such an optimization tool. We describe a series of increasingly complex designs that result in computationally hard training problems of combinatorial nature. In return for accepting classical computational hardness, we retain theoretical properties such as maximal sparsity and robustness to label noise, which are otherwise sacrificed by convex methods for the sake of computational efficiency and sound theoretical footing. In order to be compatible with emerging quantum hardware technology, we formalize the training problem as quadratic unconstrained binary optimization. Our initial investigations focus on a simple training formulation with non-convex regularization that conforms to the architecture of existing quantum hardware and makes frugal use of a limited number of available physical qubits. Next, we extend this baseline formulation to a scalable algorithm, QBoost, which is able to train incrementally large-scale classifiers on data sets of practical interest. Further, we derive another algorithm, TotalQBoost, as a theoretically motivated totally corrective boosting algorithm with cardinality penalization that also makes use of quantum optimization. Both QBoost and TotalQBoost perform explicit cardinality regularization, which is the only known way of achieving maximal sparsity in the trained classifiers. We apply QBoost and TotalQBoost to three different real-world computer vision problems and make use of a quantum processor for solving the sequence of discrete optimization problems generated by one of them. Finally, we study a learning formulation with convex regularization and a non-convex loss function, q-loss, specifically designed for robust supervised learning in the presence of label noise as it occurs in practice. For compatibility with quantum hardware we derive the corresponding quadratic binary problem via variational approximation. For all proposed algorithms we compare results on a variety of popular synthetic and natural data sets against a rich selection of existing rival learning formulations
Efficient Population Transfer via Non-Ergodic Extended States in Quantum Spin Glass
No full textQuantum tunneling has been proposed as a physical mechanism for solving binary optimization problems on a quantum computer because it provides an alternative to simulated annealing by directly connecting deep local minima of the energy landscape separated by large Hamming distances. However, classical simulations using Quantum Monte Carlo (QMC) were found to efficiently simulate tunneling transitions away from local minima if the tunneling is effectively dominated by a single path. We analyze a new computational role of coherent multi-qubit tunneling that gives rise to bands of non-ergodic extended (NEE) quantum states each formed by a superposition of a large number of deep local minima with similar energies. NEE provide a coherent pathway for population transfer (PT) between computational states with similar energies. In this regime, PT cannot be efficiently simulated by QMC. PT can serve as a new quantum subroutine for quantum search, quantum parallel tempering and reverse annealing optimization algorithms. We study PT resulting from quantum evolution under a transverse field of an n-spin system that encodes the energy function E(z) of an optimization problem over the set of bit configurations z. Transverse field is rapidly switched on in the beginning of algorithm, kept constant for sufficiently long time and switched off at the end. Given an energy function of a binary optimization problem and an initial bit-string with atypically low energy, PT protocol searches for other bitstrings at energies within a narrow window around the initial one. We provide an analytical solution for PT in a simple yet nontrivial model: M randomly chosen marked bit-strings are assigned energies E(z) within a narrow strip [-n -W/2, n + W/2], while the rest of the states are assigned energy 0. The PT starts at a marked state and ends up in a superposition of L marked states inside the narrow energy window whose width is smaller than W. The best known classical algorithm for finding another marked state is the exhaustive search. We find that the scaling of a typical PT runtime with n and L is the same as that in the multi-target Grover's quantum search algorithm, except for a factor that is equal to exp(n /(2B^2)) for finite transverse field B >>1. Unlike the Hamiltonians used in analog quantum unstructured search algorithms known so far, the model we consider is non-integrable and the transverse field delocalizes the marked states. As a result, our PT protocol is not exponentially sensitive in n to the weight of the driver Hamiltonian and may be initialized with a computational basis state. We develop the microscopic theory of PT by constructing a down-folded dense Hamiltonian acting in the space of marked states of dimension M. It belongs to the class of preferred basis Levy matrices (PBLM) with heavy-tailed distribution of the off-diagonal matrix elements. Under certain conditions, the band of the marked states splits into minibands of non-ergodic delocalized states. We obtain an explicit form of the heavy-tailed distribution of PT times by solving cavity equations for the ensemble of down-folded Hamiltonians. We study numerically the PT subroutine as a part of quantum parallel tempering algorithm for a number of examples of binary optimization problems on fully connected graphs
Modernidade dessincronizada: aceleração social, destemporalização e alienação: uma entrevista com Hartmut Rosa
No full textThe scope of this interview is to present the social experiences and the analytical categories which comprise Hartmut Rosa’s theory of social acceleration. At the outset, the questions lead the author to recall the reasons that lead to his interest in the problem of time in the present modernity, as well as the intellectual path that guided him to such an interest. The consequences of what Rosa diagnoses as a society of de-synchronized and de-temporalized acceleration are exposed and subsequently a new interpretation of the concept of alienation is proposed. Through his claim of being a successor to the school of critical social theory, Rosa also indicates the rough outlines of his critical model’s normative referential, examining the temporal maxims that make up the modern ideal of a good life.A presente entrevista traz como seu escopo uma apresentação da experiência social e das principais categorias analíticas que compõem a teoria da aceleração social de Hartmut Rosa. De início, as questões conduzem o autor a uma recapitulação dos motivos que o levaram a desenvolver seu interesse pelo problema do tempo na modernidade hodierna, bem como da trajetória intelectual que o guiou a tal interesse. São expostas as consequências daquilo que Rosa diagnostica como uma sociedade de aceleração dessincronizada e destemporalizada, e, com elas, uma nova interpretação do fenômeno da alienação. Reivindicando-se como um herdeiro da teoria crítica da sociedade, Rosa também indica os traços gerais do referencial normativo de seu modelo crítico, examinando as máximas temporais que perfazem o ideal moderno de boa vida
Preemphasis-Aware Semiconductor Optical Amplifier Model
No full textA preemphasis-aware model for SOAs with non-flat WDM inputs yielding a root-mean-square error of less than 0.05 dB is presented. It outperforms generic neural network models while using a fraction of the training data. (C) 2022 The Author(s
Active labor market policies in the OECD and in selected transition economies
No full textTransition economies have introduced a range of OECD active labor market policies to combat unemployment - albeit often on paper only, as with rising unemployment passive policies have crowded out active ones. But even in the Czech Republic, active labor market policies have contributed only marginally to reducing unemployment. One task for policymakers in Central and Eastern Europe must be to conveythe message that, even under the best circumstances, active labor policies can play only a marginal role in reducing unemployment. OECD labor policies cannot be applied mechanically in Central and Eastern Europe because the situation there is different. Severe and persistent shortages in capital and managerial ability are sure to keep labor demand weak in the medium term, while labor supply will be abundant. As enterprises are restructured and liquidated, the newly unemployed workers cannot be absorbed by the weak private sector and must compete for scarce jobs. Women and older, less educated men have particular trouble finding work. Which active labor policies does the author suggest might be effective? Limited funds for active labor policies might best be spent retraining the most able unemployed workers to develop skills needed in the private sector. Public employment programs might be targeted especially to problem groups of workers and to the long-term unemployed - more for reasons of equity than of efficiency. The point is to have a clear idea whether both aims of efficiency and equity can be pursued and, if efficiency gains are unrealistic, whether equity considerations are politically indispensable. Because nontradable services are underdeveloped, Central and Eastern European countries might eliminate credit rationing that discourages self-employment (the self-employed have trouble getting financing). Improving consulting services for the unemployed in Hungary, Poland, and Russia makes more sense than applying a broad menu of OECD programs. The labor market in the Russian Federation appears to be more dynamic than in Hungary and Poland, but this is probably because of massive labor hoarding in Russian enterprises. Once they start shedding labor in earnest, their employment figures will look more like those in the other Central and Eastern European countries.Labor Markets,Environmental Economics&Policies,Labor Policies,Public Health Promotion,Health Monitoring&Evaluation,Environmental Economics&Policies,Labor Markets,Health Monitoring&Evaluation,Economic Theory&Research,Youth and Governance
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