A cyclo-stationary complex multichannel wiener filter for the prediction of wind speed and direction

This paper develops a linear predictor for application to wind speed and direction forecasting in time and across different sites. The wind speed and direction are modelled via the magnitude and phase of a complex-valued time-series. A multichannel adaptive filter is set to predict this signal, based on its past values and the spatio-temporal correlation between wind signals measured at numerous geographical locations. The time-varying nature of the underlying system and the annual cycle of seasons motivates the development of a cyclo-stationary Wiener filter, which is tested on hourly mean wind speed and direction data from 13 weather stations across the UK, and shown to provide an improvement over both stationary Wiener filtering and a recent auto-regressive approach

Adaptive Sensor Data Acquisition for Gait Analysis

AbstractIn this paper a method is presented that uses one sensor configuration for both static and dynamic loading conditions to capture plantar pressure distribution values. In the gait analysis, different phases are from interest. The phases produces highly different signals and with conventional sensors and static data acquisition systems it is often difficult to achieve high precision measure- ments. An advanced programmable amplifier can be used to adapt the full resolution of the measurement system dynamically to the needs of the gait analyses. With the proposed system, it is possible to precisely measure the gait phases without changing any hardware. While the system is performing it is energy efficient as it only consumes power if needed. Furthermore, it is highly integrated and space saving. Thus, ideally suited for mobile outdoor applications. The technology used in this example can be applied to many different general sensor measurement questions in sports engineering

Wearable, Modular and Intelligent Sensor Laboratory

AbstractIn this paper, a modular sensor system for recording pressure distribution, 3D-acceleration, 3D-angular velocity, temperature and humidity in a shoe insole is presented. The intelligent sensor-insole is a measurement system that can be used in medical and sport related fields. Integrated sensors record physical parameters such as acceleration and or pressure which can also be used to trigger an additional feedback system. Through intelligent and high performant electronics, the feedback system is able to operate in real time. The combination of individually miniaturized systems, wireless data transmissions and a rechargeable battery enables the system for a wide field of application such as fall prevention, training analysis and motion optimization. Robust and miniaturized hardware components as well as wireless communication technology enable real-time processing of data. Measurement data can be stored locally on the measurement device for post analysis, as well as visualized on connected mobile devices such as smartphones or tablets. Aiming at using the system as a mobile and easy-to-use lab, both under laboratory conditions and in field. Applications like gait- and running analysis outside the laboratory, fall detection and activity monitoring in a home environment are possible. Due to the high performance of the system, the data pre-processing can be performed on the embedded system. Because the system supports wireless connections, it is possible to combine several of the systems to build a sensor network. Furthermore, it is possible to transmit the collected data to a cloud. The system will provide the measured data in different levels of complexity. For instance, the system is able to evaluate the data automatically and provide the results to experts such as physicians and coaches

Long Duration Life Test of Propylene Glycol Water Based Thermal Fluid Within Thermal Control Loop

Evaluations of thermal properties and resistance to microbial growth concluded that 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture was desirable for use as a fluid within a vehicle s thermal control loop. However, previous testing with a commercial mixture of PG and water containing phosphate corrosion inhibitors resulted in corrosion of aluminum within the test system and instability of the test fluid. This paper describes a follow-on long duration testing and analysis of 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture with inorganic corrosion inhibitors used in place of phosphates. The test evaluates the long-term fluid stability and resistance to microbial and chemical change

The W43-MM1 mini-starburst ridge, a test for star formation efficiency models

Context: Star formation efficiency (SFE) theories are currently based on statistical distributions of turbulent cloud structures and a simple model of star formation from cores. They remain poorly tested, especially at the highest densities. Aims: We investigate the effects of gas density on the SFE through measurements of the core formation efficiency (CFE). With a total mass of $\sim2\times10^4$ M$_\odot$, the W43-MM1 ridge is one of the most convincing candidate precursor of starburst clusters and thus one of the best place to investigate star formation. Methods: We used high-angular resolution maps obtained at 3 mm and 1 mm within W43-MM1 with the IRAM Plateau de Bure Interferometer to reveal a cluster of 11 massive dense cores (MDCs), and, one of the most massive protostellar cores known. An Herschel column density image provided the mass distribution of the cloud gas. We then measured the 'instantaneous' CFE and estimated the SFE and the star formation rate (SFR) within subregions of the W43-MM1 ridge. Results: The high SFE found in the ridge ($\sim$6% enclosed in $\sim$8 pc$^3$) confirms its ability to form a starburst cluster. There is however a clear lack of dense cores in the northern part of the ridge, which may be currently assembling. The CFE and the SFE are observed to increase with volume gas density while the SFR steeply decreases with the virial parameter, $\alpha_{vir}$. Statistical models of the SFR may well describe the outskirts of the W43-MM1 ridge but struggle to reproduce its inner part, which corresponds to measurements at low $\alpha_{vir}$. It may be that ridges do not follow the log-normal density distribution, Larson relations, and stationary conditions forced in the statistical SFR models.Comment: 13 pages, 7 figures. Accepted by A&

Neutralino Relic Density in a Supersymmetric U(1)' Model

We study properties of the lightest neutralino (\chi) and calculate its cosmological relic density in a supersymmetric U(1)' model with a secluded U(1)' breaking sector (the S-model). The lightest neutralino mass is smaller than in the minimal supersymmetric standard model; for instance, m_\chi < 100 GeV in the limit that the U(1)' gaugino mass is large compared to the electroweak scale. We find that the Z-\chi-\chi coupling can be enhanced due to the singlino components in the extended neutralino sector. Neutralino annihilation through the Z-resonance then reproduces the measured cold dark matter density over broad regions of the model parameter space.Comment: Version to be published in Physics Letters B. 13 pages, Revtex4, epsf.sty, 13 postscript figure