Two heads better than one: pattern discovery in time-evolving multi-aspect data

Data stream values are often associated with multiple aspects. For example each value observed at a given time-stamp from environmental sensors may have an associated type (e.g., temperature, humidity, etc.) as well as location. Time-stamp, type and location are the three aspects, which can be modeled using a tensor (high-order array). However, the time aspect is special, with a natural ordering, and with successive time-ticks having usually correlated values. Standard multiway analysis ignores this structure. To capture it, we propose 2 Heads Tensor Analysis (2-heads), which provides a qualitatively different treatment on time. Unlike most existing approaches that use a PCA-like summarization scheme for all aspects, 2-heads treats the time aspect carefully. 2-heads combines the power of classic multilinear analysis with wavelets, leading to a powerful mining tool. Furthermore, 2-heads has several other advantages as well: (a) it can be computed incrementally in a streaming fashion, (b) it has a provable error guarantee and, (c) it achieves significant compression ratio against competitors. Finally, we show experiments on real datasets, and we illustrate how 2-heads reveals interesting trends in the data. This is an extended abstract of an article published in the Data Mining and Knowledge Discovery journal.     

A Converging Wall-Jet Instrument for Ion Selective Electrode Dynamic Response Studies

Abstract

Ion selective electrodes are used to conduct real-time measurements of gaseous thermal degradation products from halon replacement experiments. Response characteristics of these ion selective electrodes are needed to address potential interferences and surface poisoning experienced under field conditions. The design and the fabrication of an in situ, converging wall-jet instrument for the measurement of the dynamic responses of ion selective electrodes are described. Various time delays associated with the generation and detection of ion activity steps have been quantitatively determined.

Dynamic response measurements for iodide steps on a Corning iodide/cyanide ion selective electrode are comparable to those obtained on the best of the earlier instrument designs, the in situ, switched wall-jet instrument. The advantages of the converging wall-jet instrument over the switched wall-jet instrument are identified.     

Optimisation of puffing naked barley

The expansion of volume (the puffing index) of naked barley was investigated at various operating conditions of the puffing process. The purpose was to optimise the manufacture of expanded grains of the naked barley cultivars that have exceptional nutritional value for humans. The influence of the following parameters on the puffing index was investigated: the mass and the moisture content of the charge of the puffing barrel, pressure and temperature during the puffing process, the cultivar of barley, pre-processing of the grain (grinding and polishing), adding water into the barrel and the sensory quality of the product.

A regression equation was established for the calculation of the puffing index as a function of the operating parameters. The puffing index is influenced especially by the operating temperature and pressure. There was no influence found of mass of the charge, the cultivar of barley, the degree of grinding of barley, washing of the grains and adding water on the puffing index. The puffing index is not the sole indicator of the quality of the expanded product. It is necessary to take into account the sensory evaluation. A quality expanded naked barley was obtained at the operating temperature of 550 °C and pressure from 0.9 to 1.0 MPa with the moisture content of the charge around 16.5%.     

Rapid screening for taxanes by tandem mass spectrometry.

A highly specific and sensitive method is described for determining taxol, cephalomannine, and baccatin III in crude plant extracts. Radical anions of the taxanes are formed by desorption chemical ionization, and a parent tandem mass spectrometric scan is used to recognize these compounds by their characteristic dissociations. The limit of detection of the individual taxanes in typical plant matrices is less than 500 pg when all three species are screened simultaneously. Because of the sensitivity of the method, extraction times can be shortened to 30 min and crude extracts can be examined at the rate of 6/h. Detection of all three taxanes extracted from a single Taxus cuspidata needle in a combined extraction/analysis time of less than 1 h is demonstrated.     

A double-recessed Al0.24GaAs/In0.16GaAspseudomorphic HEMT for Ka- and 𝒬-band power applications

A double-recessed 0.2-μm-gate-length pseudomorphic HEMT (PHEMT) has been demonstrated with 500 mW of output power (833 mW/mm of gate periphery), 6-dB gain, and 35% power-added efficiency (PAE) at 32 GHz. At 44 GHz, the device exhibited 494 mW of output power (823 mW/mm), 4.3-dB gain, and 30% PAE. This level of performance is attributed to excellent MBE material, optimized epitaxial layer design, and the use of individual source vias and of double recess with tight channel dimensions. Excellent 3-in-wafer uniformity was also observed: DC yield was greater than 95% and the interquartile range for all DC parameters was less than 20% of the median value (most are significantly lower)     

Decrease in cardiovascular disease mortality in the Czech Republic from 1984 to 1993 and its possible causes

BACKGROUND: The objective of the investigation was to evaluate the ten-year development of the cardiovascular mortality rate in two population groups in the age bracket from 25 to 64 years, i.e. in subjects living in six districts which participated in the international WHO project MONICA and in the population of the whole Czech Republic. METHODS AND RESULTS: Data on the mortality rate in 1984-1993 for the age group from 25-64 years were provided by the Institute of Health Information and Statistics, information on the prevalence of risk factors was obtained in three cross-sectional studies implemented in six districts as part of the MONICA project in 1985, 1988 and 1992. In the mortality rate per 100,000 population in the six districts the following changes were revealed (in parentheses the values for 1984 and 1993 are given): men - a statistically significant declining trend in the from all caused mortality (849.3-742.5; p < 0.001) and cardiovascular mortality (367.2-280.4; p < 0.001) and cerebrovascular mortality (69.7-44.8; p < 0.001). In the mortality from ischaemic heart disease (215.7-170.6; ns) a declining trend was not recorded. In women aged 25-64 years in the six districts there was a statistically significant decline of the mortality from all caused (359.5-322.1; p < 0.001), the cardiovascular mortality (115.6-100.6; p < 0.001) and cerebrovascular mortality (31.1-23.6; p < 0.001). The mortality from ischaemic heart disease did not change (49.2-48.8; ns). In the population of the Czech Republic in men the following were detected: a drop of the from all caused mortality (907.1-784.8; P < 0.001), the cardiovascular mortality (383.5-308.4; p < 0.001) and cerebrovascular mortality (76.5-55.3; p < 0.001). Also in women of the Czech Republic a decline of the mortality from all caused was recorded (390.1-328.5; p < 0.001), the cardiovascular mortality (135.3-103.8; p < 0.001), ischaemic heart disease (58.0-48.6; p < 0.001) and cerebrovascular mortality (43.5-27.4; p < 0.001). In 1990 an increased cardiovascular mortality was recorded in men different from the trend during 1984-1993, statistically significant in the Czech Republic (p < 0.05) and in the six districts (p < 0.05). The reasons of this trend are not clear. The role of health services in the mortality drop is not clear, although available data indicate their improvement. Favourable changes were found in risk factors: during the period from 1985-1992 the prevalence of hypercholesterolaemia declined significantly in men and women, the prevalence of hypertension in women and the prevalence of smoking in men declined in the six districts. From nationwide data ensues that after 1989 significant changes occurred in the diet of the Czech population. The meat consumption declined by 1993 by 13%, the milk and dairy product consumption by 26.8% the butter consumption by 43.6% the consumption of vegetable fats increased by 16%, of vegetables by 8%, tropical fruit by 43.2%. These changes probably had an impact on the cholesterol level and BMI of the Czech population. CONCLUSIONS: In the declining cardiovascular mortality trend during 1984-1993 the following may have participated: improved medical care, dietary changes, improvement of the risk profile and other, in particular socioeconomic factors. With regard to the close temporal association of the investigated changes it may be assumed that this development is at least partly associated with changes of the political and economic position in the Czech Republic after 1989.     

High efficiency single pulse doped Al0.60In0.40As/GaInAs/InP HEMTs for Q-band power applications

Single pulse doped, 0.2 μm-gate Al_0.60In_0.40 As/GaInAs/InP HEMTs have been fabricated and characterised. The complete process sequence for the HEMTs includes SiN_x passivation and dry etched via hole fabrication. Power measurements at 44 GHz on a 10×60 μm² device yielded 225 mW output power, 5 dB associated gain, and 39% power added efficiency. The results indicate that the single pulse doped InP-based HEMTs are suitable for high power applications at Q-band     

High performance 0.35 μm gate-length monolithicenhancement/depletion-mode metamorphicIn0.52Al0.48As/In0.53Ga0.47As HEMTs on GaAs substrates

Monolithic integration of enhancement (E)- and depletion (D)-mode metamorphic In_0.52Al_0.48As/In_0.53Ga_0.47 As/GaAs HEMTs with 0.35 μm gate-length is presented for the first time. Epilayers are grown on 3-inch SI GaAs substrates using molecular beam epitaxy. A mobility of 9550 cm²/V-s and a sheet density of 1.12×10^{12 -2} are achieved at room temperature. Buried Pt-gate was employed for E-mode devices to achieve a positive shift in the threshold voltage. Excellent characteristics are achieved with threshold voltage, maximum drain current, and extrinsic transconductance of 100 mV, 370 mA/mm and 660 mS/mm, respectively for E-mode devices, and -550 mV, 390 mA/mm and 510 mS/mm, respectively for D-mode devices. The unity current gain cutoff frequencies of 75 GHz for E-mode and 80 GHz for D-mode are reported