Online bin stretching with three bins

Online bin stretching is a semi-online variant of bin packing in which the algorithm has to use the same number of bins as an optimal packing, but is allowed to slightly overpack the bins. The goal is to minimize the amount of overpacking, i.e., the maximum size packed into any bin. We give an algorithm for online bin stretching with a stretching factor of \(11/8 = 1.375\) for three bins. Additionally, we present a lower bound of \(45/33 = 1.\overline{36}\) for online bin stretching on three bins and a lower bound of 19/14 for four and five bins that were discovered using a computer search.     

Observation of a half-quantum-flux periodicity pattern in an rf SQUID with small critical currents

We have found experimentally that rf SQUID's working in a nonhysteretic mode with small critical currents give exactly at resonance and at very low rf bias a triangular pattern with a period equal to half of one elementary quantum of magnetic flux. We discuss a possible explanation of this peculiar result.     

Thermal-induced evolution of secondary phases in Cr–Mo–V low alloy steels

Four low alloy steels with different contents of molybdenum and vanadium were investigated. The steels were annealed at 773, 793, 853, 873, 933, 973, and 993 K for 500, 1000, 3000, and 10000 h. Techniques of transmission electron microscopy and thermodynamic calculations (ThermoCalc) were used to characterise influence of the steel bulk composition and the annealing conditions on evolution of carbides M₃C, M₂C, M₇C₃, M₂₃C₆, M₆C, and MC (M=metallic element). Changes in structure types and metal compositions of the carbides were characterised in detail. The work was done with the intention to obtain more information about the secondary phase evolution in low alloy steels used in energy industries.     

Experimental Investigation of the Properties of Lime-Based Plaster-Containing PCM for Enhancing the Heat-Storage Capacity of Building Envelopes

Experimental analysis of a wide range of properties of a lightweight plaster which should enhance the heat-storage capacity of building envelopes is presented. The basic physical characteristics, namely, the bulk density, matrix density, total open porosity, and pore-size distribution are measured at first. Then, the compressive strength is determined for an assessment of mechanical performance of the plaster. The thermal conductivity and thermal diffusivity are studied using an impulse technique. Differential scanning calorimetry measurements are performed as well, in order to identify the temperature range and latent heat of the phase change and to determine the specific heat capacity as a function of temperature. Durability properties are assessed using the measurement of the water absorption coefficient and sorption and desorption isotherms. The experimental results indicate a good capability of the designed plaster to moderate effectively the interior climate of buildings.     

Continuous Separation of an H2SO4/CuSO4 Mixture by Diffusion Dialysis

The separation of a mixture of sulfuric acid and copper sulfate is experimentally investigated in a two‐compartment countercurrent dialyzer at steady state using an anion‐exchange membrane. The dialysis process is characterized by the recovery yield of acid, the rejection coefficient of salt, and the permeability coefficient of the membrane. The simultaneous transport of sulfuric acid and copper sulfate is quantified by four phenomenological coefficients, which are dependent on the acid and salt concentrations in the feed. They are determined by a procedure consisting of (i) the numerical integration of the basic differential equations describing the concentration profiles of both components on both sides of the membrane and (ii) the optimizing method.     

Industrial architecture and negativity: the aesthetics of architecture in the works of Gordon Matta-Clark,Robert Smithson and Bernd and Hilla Becher

The modernist idea of monumentality derived its inspiration from the imagery of late-nineteenth century industrial structures. In the 1960s, this monumentality and modernist 'total design' was criticised by Robert Venturi and Denise Scott-Brown who proposed the 'ugly and ordinary' architecture and 'vital mess' of commercial populism instead. On the background of these two approaches, I will read the art works of Gordon-Matta Clark, Robert Smithson and Bernd and Hilla Bechers as giving voice to all that is forgotten, excluded or unacknowledged in architecture. The importance of these artists lies in their exploration of negativity in architecture. Their art works stage the contras, first, between the inevitable continuity of architecture as a process and its discontinuity when it is reduced to a set of objects, as well as the contrast, secondly, between the continuity of urban and architectural space and its discontinuity when our perceptions reduce it to its monumental and important parts. Negativity stands for the time 'before' and 'after' of what is commonly understood as an architecture, as well as for the 'invisible' materiality parts of urban space and buildings that are usually ignored. Today, it is in obsolete industrial architecture that negativity finds its purest expression: in the words of Walter Benjamin, the Modernists' imaginary monuments are recognised as ruins even before they have physically crumbled.     

Guided-wave Electro-optic X-type Switches: Symmetry,Switching Characteristics and Cross-talk

Abstract

The influence of branching asymmetry and electrode offset on the switching characteristics and cross-talk of X-type switches is analysed theoretically. The relationship between the switch symmetry (i.e. the existence of a plane or centre of inversion) and the switching characteristics is found. Cross-talk levels of slightly asymmetric Ti:LiNbO₃ switches are calculated.     

An experimental test of Occam’s razor in classification

A widely persisting interpretation of Occam’s razor is that given two classifiers with the same training error, the simpler classifier is more likely to generalize better. Within a long-lasting debate in the machine learning community over Occam’s razor, Domingos (Data Min. Knowl. Discov. 3:409–425, 1999) rejects this interpretation and proposes that model complexity is only a confounding factor usually correlated with the number of models from which the learner selects. It is thus hypothesized that the risk of overfitting (poor generalization) follows only from the number of model tests rather than the complexity of the selected model. We test this hypothesis on 30 UCI data sets using polynomial classification models. The results confirm Domingos’ hypothesis on the 0.05 significance level and thus refutes the above interpretation of Occam’s razor. Our experiments however also illustrate that decoupling the two factors (model complexity and number of model tests) is problematic.