Modeling the growth of fingerprints improves matching for adolescents

We study the effect of growth on the fingerprints of adolescents, based on which we suggest a simple method to adjust for growth when trying to recover a juvenile's fingerprint in a database years later. Based on longitudinal data sets in juveniles' criminal records, we show that growth essentially leads to an isotropic rescaling, so that we can use the strong correlation between growth in stature and limbs to model the growth of fingerprints proportional to stature growth as documented in growth charts. The proposed rescaling leads to a 72% reduction of the distances between corresponding minutiae for the data set analyzed. These findings were corroborated by several verification tests. In an identification test on a database containing 3.25 million right index fingers at the Federal Criminal Police Office of Germany, the identification error rate of 20.8% was reduced to 2.1% by rescaling. The presented method is of striking simplicity and can easily be integrated into existing automated fingerprint identification systems

MLSys: The New Frontier of Machine Learning Systems

Machine learning (ML) techniques are enjoying rapidly increasing adoption. However, designing and implementing the systems that support ML models in real-world deployments remains a significant obstacle, in large part due to the radically different development and deployment profile of modern ML methods, and the range of practical concerns that come with broader adoption. We propose to foster a new systems machine learning research community at the intersection of the traditional systems and ML communities, focused on topics such as hardware systems for ML, software systems for ML, and ML optimized for metrics beyond predictive accuracy. To do this, we describe a new conference, MLSys, that explicitly targets research at the intersection of systems and machine learning with a program committee split evenly between experts in systems and ML, and an explicit focus on topics at the intersection of the two

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

The enormous quantity of food wastes discarded annually force to look for alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the imperatives of the nowadays society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for recovery of added value compounds and detection by modern technologies and are an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels

Neuartige Tankschwingkreise für Hochfrequenz-SQUIDs

SQUIDs (Superconducting Quantum Interference Devices) are flux-to-voltage transducers, providing an output voltage that is periodic in the applied flux with aperiod of one flux quantum, $\Phi_{0} \equiv$ h/2e $\simeq$ 2.07 x 10$^{-15}$ Wb. They can measure fractions ($\sim$ 10$^{-7}$) of $\phi_{0}$ and are the most sensitive sensors of magnetic flux (and field) known today. SQUID research was intensified due to the discovery of high-temperature-superconductors (HTS). Applications of HTS SQUID magnetometer systems indude e.g. biomagnetic diagnostics, nondestructive evaluation of materials and geomagnetic exploration. The single junction SQUID involves a Josephson junction interfering the current flow around a superconductiong loop and is operated with a radiofrequency (rf SQUID) or highfrequency (hf SQUID) flux bias provided by a tank circuit. At present, the intrinsic and practical limits of their magnetometer performance are far from being attained. The basic issue of this work was to analyze characteristic features and the capability of improvement with the aim to find new design concepts for lower field resolutions. For achieving that aim, the tank circuit is the potentially most effective part of the sensor. In principle, an improved magnetometer performance could be reached by increasing the bias frequency and the quality factor of the tank circuit while its effective coupling strength to the SQUID should be adjusted dose to a minimum treshold value. Since theoperation frequency of hf SQUIDs entered the GHz range, it was important to investigate their hf-characteristics in relation to magnetometer attributes. An intensive inter action of appropriate knowledge from hf and sensor technology has, therefore, been started in this work. Note that due to the experience of this work, the optimization of the tank circuit and SQUID design should not be performed seperately because the coupling between tank circuit and SQUID is a central and critical aspect for the magnetometer performance. A new simulation method has been developed to characterize the basic hf and magnetometer features of hf SQUIDs, especially the coupling between tank circuit and SQUID structure. New measurement techniques have been explored to obtain important hf and SQUID parameters and a complete signal analysis, which are usually not obtainable from standard SQUID electronic readouts. The new simulation and measurement methods have been testet with several existing hf SQUID structures and studies of different coupling arrangements (e.g. S-resonator SQUIDs with indirect or direct coupling, with or without flux focussing pads) and hf-environments (one or two port readout scheme, diode or mixer detector) were performed. The gained know-how supported the inventions ofseveral new hf SQUID concepts. One attempt was to use the SQUID loop with the surrounding flux focussing structure as an integrated hf resonator which renders an external tank circuit superfluous and turned out to function. Other ideas were to use HTS planar high-Q resonators (like stripline resonators or even lumped element resonators) or dielectric high-Q resonators coupled to washer SQUIDs, preferably as endplates in a modular arrangement. At 77 K, field resolutions of 130 fT / $\sqrt{Hz}$ (LC resonator) and 105 fT / $\sqrt{Hz}$ (dielectric resonator) were obtained, one order of magnitude lower compared to the well known S-resonator SQUIDs. Further developments of the new ideas should lead to even more sensitive single junction SQUID magnetometers

Structure, magnetism and excitations in some Mn-based magnetocaloric effect compounds

The magnetocaloric effect causes the cooling or heating of a material due to the influence of an applied magnetic field. This mechanism provides an alternative technique for cooling, when using cheap and environment friendly materials. Heating and cooling takes place without moving any mechanical parts. Therefore, this effect attracts the attention of many scientific studies. The magneto caloric effect is characterized by the entropy change. Polycrystalline samples of the compositions Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=0,1,2,3,4 and a single crystal of the composition Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4 were prepared in order to analyze the magnetocaloric effect in those materials. All samples were characterized with magnetization measurements. Ferroand antiferromagnetic behaviour could be detected. Diffraction patterns were taken on the timeof- flight powder diffractometer POWGEN at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory to analyze the magnetic structures of the compounds. Inelastic neutron data were collected on the single crystal Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4 on the thermal neutron triple axis spectrometer 2T1 at Laboratoire Léon Brillouin to investigate the dynamic properties. The refined data taken on samples Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=0,1,2,3,4 on POWGEN at room temperature confirm the hexagonal structure. This has already been reported in literature. Anomalies could be identified in several crystallographic parameters as funtion of the Fe-content of the samples Diffraction patterns taken on sample Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=0 between the phase transitions at 70K and 90K could be refined with an orthorhombic unit cell including antiferromagnetism. Below the phase transition at 62K the best refinements could be performed using a monoclinic unit cell. Also, the structure seems to exhibit weak ferromagnetism, which can be annihilated with an applied magnetic field. This mechanism is proposed to cause the negative magnetocaloric effect in this compound. The analysis of diffraction patterns taken in the ferromagnetic phase of Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4 indicate different behaviours of the magnetic atoms occupying the two crystallographic positions (the third is occupied by Si). This property is proposed to influence significantly the entropy in this material. Phonon branches in the dispersion relation of Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4 are anisotropic, which is due to the hexagonal structure. In order to investigate the effect of Fe and Mn on the change of the entropy the composition Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4 was doped with Co (for Mn and Fe). The analysis of the diffraction patterns which were taken on POWGEN identified at least one impurity phase in every sample. Different behaviours of the magnetic moments of the atoms in these compounds could also be verified, which is similar to the composition Mn$_{5−x}$Fe$_{x}$Si$_{3}$ x=4