Synergetic Use Research Articles

Cirrus Cloud Radiative Forcing Derived from Synergetic Use of MODIS Analyses and Ground-Based Observations

We have been performing radiative budget measurements at a ground-based observatory located on Fukue Island. In this study, we analyzed the data from instruments installed in the observatory and the data observed by MODIS, the satellite-borne imager, to evaluate cirrus cloud radiative forcing (CRF). The result shows that CRF took a large positive value as 127.98 W m-2 at the top of the atmosphere (TOA) and a small positive value as 13.2 W m-2 at the surface. As a result, it was found that optically very thin cirrus clouds exert a strong warming effect on the Earth's system and a weak warming effect on the Earth's surface when aerosols are not taken into account.

Synergetic use of different evaluation, parameterization and search tools within a multilevel optimization platform

This paper presents the synergetic use of different evaluation tools, parameterization schemes and search methods on the levels of a multilevel optimization platform to efficiently solve single- and multi-objective computationally demanding optimization problems. The platform is formed by a number of levels which concurrently search for optimal solutions, by regularly exchanging promising individual solutions. Each level is associated with a problem-specific evaluation tool with its own accuracy and computational cost, a parameterization scheme which determines the design variables and their mapping to generate individual solutions and a search algorithm which is either a metamodel-assisted evolutionary algorithm or a gradient-based method. The use of the multilevel platform with only one of the aforementioned features changing from level to level was presented in a previous paper by the authors. The present paper shows that the combined use of hierarchical evaluation, hierarchical parameterization and hierarchical search decreases further the computational cost by increasing the efficiency of the optimization method. This is demonstrated on function minimization and aerodynamic shape optimization problems; though only two levels are used herein, this is not a restriction and the optimization platform may accommodate any number of them.

Non-contact detection of myocardium’s mechanical activity by ultrawideband RF-radar and interpretation applying electrocardiography

Electromagnetic waves can propagate through the body and are reflected at interfaces between materials with different dielectric properties. Therefore the reason for using ultrawideband (UWB) radar for probing the human body in the frequency range from 100 MHz up to 10 GHz is obvious and suggests an ability to monitor the motion of organs within the human body as well as obtaining images of internal structures. The specific advantages of UWB sensors are high temporal and spatial resolutions, penetration into object, low integral power, and compatibility with established narrowband systems. The sensitivity to ultralow power signals makes them suitable for human medical applications including mobile and continuous noncontact supervision of vital functions. Since no ionizing radiation is used, and due to the ultralow specific absorption rate applied, UWB techniques permit noninvasive sensing with no potential risks. This research aims at the synergetic use of UWB sounding combined with magnetic resonance imaging (MRI) to gain complementary information for improved functional diagnosis and imaging, especially to accelerate and enhance cardiac MRI by applying UWB radar as a noncontact navigator of myocardial contraction. To this end a sound understanding of how myocardial's mechanic is rendered by reflected and postprocessed UWB radar signals must be achieved. Therefore, we have executed the simultaneous acquisition and evaluation of radar signals with signals from a high-resolution electrocardiogram. The noncontact UWB illumination was done from several radiographic standard positions to monitor selected superficial myocardial areas during the cyclic physiological myocardial deformation in three different respiratory states. From our findings we could conclude that UWB radar can serve as a navigator technique for high and ultrahigh field magnetic resonance imaging and can be beneficial preserving the high resolution capability of this imaging modality. Furthermore it can potentially be used to support standard electrocardiography (ECG) analysis by complementary information where sole ECG analysis fails, e.g., electromechanical dissociation.

Retrieval of tropospheric NO2 columns from satellite measurements in presence of cirrus: A theoretical sensitivity study using SCIATRAN and prospect application for the A-Train

Abstract A theoretical sensitivity study of the influence of cirrus cloud properties on tropospheric NO2 columns retrieved from the spaceborne Ozone Monitoring Instrument (OMI) measurements is performed. It is conducted within the framework of the synergetic use of A-Train sensors to derive more representative trace gas products. We aim to study the potential effects of cirrus clouds on tropospheric NO2 retrievals using a retrieval algorithm that, unlike the OMI Standard and DOMINO algorithms, does not correct for the effects of clouds. The sensitivity study is based on the radiative transfer code SCIATRAN that performs both simulations of top of atmosphere (TOA) reflectances as measured by an OMI-like band and tropospheric NO2 column retrievals based on the differential optical absorption spectroscopy (DOAS) method. The results of the sensitivity study show that if a correction for cirrus clouds is not included in our simple retrieval that does not account for clouds in the first place, the tropospheric column can be underestimated by 55%. This underestimation depends strongly on cirrus parameters as, in order of importance, cloud fraction, cloud optical depth, asymmetry factor of cirrus cloud phase function and cloud top height. The perspective of the synergy between OMI and cloud information obtained from cloud-derived products of the A-Train is evaluated in two parts by applying a simple cloud correction scheme based on the independent pixel approximation (IPA). Firstly, we evaluated the tropospheric NO2 column retrievals error caused by uncertainties in cirrus cloud properties. Secondly we studied the influence of subpixel cloud optical depth variability on NO2 retrievals. From our simulations, it is demonstrated that the error will be reduced significantly if the cloud fraction is lower or equal to 0.5. In this case, the cloud fraction and the cloud optical depth must be known within accuracy less than 0.05% and 50%, respectively. The cloud top height and the asymmetry factor must be known within uncertainty of at least 1 km and less than 0.05, respectively. The latter result shows that the uncertainty of the asymmetry factor is a major source of error in the cloud correction for tropospheric NO2 retrieval in the presence of cirrus.

Ubiquitous computing in sports: A review and analysis

Ubiquitous (pervasive) computing is a term for a synergetic use of sensing, communication and computing. Pervasive use of computing has seen a rapid increase in the current decade. This development has propagated in applied sport science and everyday life. The work presents a survey of recent developments in sport and leisure with emphasis on technology and computational techniques. A detailed analysis on new technological developments is performed. Sensors for position and motion detection, and such for equipment and physiological monitoring are discussed. Aspects of novel trends in communication technologies and data processing are outlined. Computational advancements have started a new trend – development of smart and intelligent systems for a wide range of applications – from model-based posture recognition to context awareness algorithms for nutrition monitoring. Examples particular to coaching and training are discussed. Selected tools for monitoring rules' compliance and automatic decision-making are outlined. Finally, applications in leisure and entertainment are presented, from systems supporting physical activity to systems providing motivation. It is concluded that the emphasis in future will shift from technologies to intelligent systems that allow for enhanced social interaction as efforts need to be made to improve user-friendliness and standardisation of measurement and transmission protocols.

Spintronic materials and devices: Advances and applications

Advances in present-day microelectronics and magnetic data storage devices depend critically on the technological ability to produce device structures of ever-decreasing dimensions. With the typical device dimensions approaching nanometer scale, the materials design parameters are being pushed to their optimum values. Continued device miniaturization is becoming increasingly challenging. There is now a general consensus that the current rate of miniaturization cannot be sustained and new approaches of device fabrication need to be developed. Spintronics is one such approach that is based on the synergetic use of charge and spin dynamics of electrons in certain multifunctional materials. There are various novel device concepts which have been proposed based on this technology, and a few (e.g., read heads for magnetic recorders and nonvolatile memory components) have already found practical applications. The critical step in the functioning of a spintronics device is the injection and detection of spin-polarized carriers at the ferromagnet-semiconductor interface. Despite considerable efforts, effi cient injection of spins into nonmagnetic semiconductors still continues to be a major obstacle in this fi eld. Ferromagnetic metals such as iron and nickel were used in earlier studies for injecting spin-polarized carriers into a semiconducting transport medium. However, in most of the studies the degree of spin polarization of injected carriers was less than a disappointing 1%. In order to overcome this, three different Spintronic Materials and Devices: Advances and Applications

Synergetic use of TERRA/MODIS imagery and meteorological data for studying aerosol dust events in Cyprus

This paper presents the results from the analysis of TERRA/Moderate Resolution Imaging Spectrometer (MODIS) images for the detection and mapping of particulate air pollution in Cyprus. For this purpose, a set of selected air pollution events for the year 2002 was used, mainly associated with dust transported over the area from the surrounding deserts. The results depict the potential of the use of remotely sensed data (MODIS) for monitoring and air pollution quality mapping at a full extent over Cyprus, providing useful information that could be used in combination with other available data sources (meteorological data, ground-based air pollution monitoring stations, etc.).

Computational time reversal acoustics imaging of embedded defects in solid media

Time reversal acoustics (TRA) techniques can exploit the nonlinear processes emerging from the interaction between the incident waves and nonlinear scatterers in solid media in order to localize and characterize the scatterers themselves. When nonlinear scatterers are embedded, their localization can be obtained through a mixed experimental/numerical TRA procedure: the forward propagation is performed experimentally, while the time reversal (TR) backward propagation is simulated using computational codes and a reference model of the solid. The synergetic use of dedicated processing of the forward propagation signals collected at the time reversal mirror (TRM), for example with nonlinear elastic wave spectroscopy (NEWS) techniques, and the calculation of the backpropagated wave fields at each point within the specimen leads to imaging of the nonlinear scatterers. We show examples of nonlinear scatterer (macroscopic cracks, distributed microcracks) imaging by such a procedure, exploiting high performance (parallel) computational codes. We address issues in the imaging method related to the discrepancy between the reference model of the specimen and the real specimen itself. Finally, we address the implementation of the technique for non-destructive Evaluation (NDE) real-world applications using multi-threaded computational codes to be run on common multicore desktop computers.

Synergetic Use of Radar and Optical Satellite Images to Support Severe Storm Prediction for Offshore Wind Farming

In this paper, we show how satellite images taken by space-borne radar sensors can be used to determine mesoscale high-resolution wind fields in synergy with cloud parameters from optical data and, thus, help in the task of maintenance and planning offshore wind farms. The aim of this paper is to use synthetic aperture radar (SAR) and medium resolution imaging spectrometer (MERIS) onboard the environmental satellite (ENVISAT) in synergy to analyze severe weather systems, in particular, to describe the spatial evolution of the atmospheric boundary layer processes involved in cold air outbreaks. We investigated the fine-scale structure of a severe weather case on November 1, 2006 over the North Sea using satellite data. The satellite data are compared with numerical model results of the German Weather Service ldquoLokal Modellrdquo (LM) and the high-resolution limited area model (HIRLAM). LM and HIRLAM show differences in mesoscale turbulent behavior and coastal shadowing. Maximum wind speeds of up to 25 m/s are measured by SAR and are confirmed by the models. Significant differences are observed in the location of the maxima. High-resolution ENVISAT ASAR measurements provide very detailed information on small-scale atmospheric features, which seem to not be captured well by the analyzed numerical models, in particular, in coastal areas. Meteosat second generation (MSG) is used to determine the movement of cloud patterns. Cloud patterns seen in the optical data and radar cross-section modulation give a consistent dynamical picture of the atmospheric processes. The relevance for offshore wind farming is discussed.

Review of methods of small‐footprint airborne laser scanning for extracting forest inventory data in boreal forests

Experiences from Nordic countries and Canada have shown that the retrieval of the stem volume and mean tree height of a tree or at stand level from laser scanner data performs as well as, or better than, photogrammetric methods, and better than other remote sensing methods. This paper reviews the methods of small‐footprint airborne laser scanning for extracting forest inventory data, mainly in the boreal forest zone. The methods are divided into the following categories: extraction of terrain and canopy height model; feature extraction approaches (canopy height distribution and individual‐tree‐based techniques, techniques based on the synergetic use of aerial images and lidar, and other new approaches); tree species classification and forest growth using laser scanner; and the use of intensity and waveform data in forest information extraction. Despite this, the focus is on methods, some review of quality obtained, especially in the boreal forest area, is included. Several recommendations for future research are given to foster the methodology development.

Case study of wind jet transition and localized responses of wind wave along the pacific coast of Northern Japan by synergetic use of satellite and in situ observations

We present a case study of low-level wind jets induced in sequence by orographic effects off the Pacific coast of northern Japan during 7–11 June 2003, and demonstrate that the transition of the wind jets causes areal differences of wave height variations along the coast. First, we describe evolution and structure of the wind jet by analyzing SeaWinds scatterometer wind measurements. Under the easterly wind, a strong wind jet formed after passing by Cape Erimo. As the wind shifted to the southeast, the wind jet started to decay. In turn, the southerly wind along the coast led to another wind jet in the lee of the easternmost tip of the Sanriku coast. We then identify onsets and decays of the wind jets from time series of wind speed at meteorological stations. Finally, we demonstrate that the transition of the wind jets has local impacts on wave height variations. Significant wave heights measured by altimeters were correlated positively with local wind energy, i.e., squares of wind speeds. Accompanying the wind jet formation/decline, significant differences of wave height variations became marked among wave observation stations located along the coast at intervals of up to 50 km.

One‐dimensional variational retrieval of aerosol extinction coefficient from synthetic LIDAR and radiometric measurements

The Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) [onboard the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) platform] and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument (onboard the AQUA platform) will provide simultaneous measurements as part of the “AQUA‐train,” thus offering a unique opportunity to improve our knowledge on aerosol properties and their spatial distribution. Here we investigate to which extent both the vertical distribution of the aerosol extinction coefficient and the aerosol bimodal size distribution can be retrieved from a synergetic use of the vertically‐resolved lidar signal and the spectral radiance measurements. To this effect, a variational retrieval scheme based on a simplified radiative transfer model was developed. The extinction‐coefficient profile for fine and coarse‐mode aerosols was retrieved from synthetic observations of the profile of the attenuated backscatter lidar signal at two wavelengths and radiances at six wavelengths. Our method aims at minimizing a cost function which measures the departure of the solution to the observations. The adjoint method was applied to find the gradient of the cost function with respect to the input parameters. The retrieval scheme was tested under a realistic noise level and different microphysical perturbations. The retrieval of extinction‐coefficient profiles, for fine and coarse particles, is successful if there is a predominance of fine particles. If coarse particles dominate over fine ones, the scheme retrieves the profile of the total extinction coefficient with a higher confidence than that of the fine mode. When perturbations on the aerosol microphysical properties are introduced, thus simulating a more challenging case with incomplete information of the aerosol model present in the atmosphere, the scheme shows a very good performance in terms of total extinction‐coefficient retrieval but less success for individual modes. It retrieves the modal radii for both modes simultaneously but can not retrieve at the same time the refractive index and true‐mode radii for both modes. Results also reveal that there is some prospect for improvement in the quality of the retrieval by either increasing the size of the predefined set of aerosol models or by including other sources of independent information such as Polarization and Directionality of Earth Reflectances (POLDER)‐like measurements.

Potential Synergetic Use of GNSS-R Signals to Improve the Sea-State Correction in the Sea Surface Salinity Estimation: Application to the SMOS Mission

It is accepted that the best way to monitor sea surface salinity (SSS) on a global basis is by means of L-band radiometry. However, the measured sea surface brightness temperature (TB) depends not only on the SSS but also on the sea surface temperature (SST) and, more importantly, on the sea state, which is usually parameterized in terms of the 10-m-height wind speed (U10 ) or the significant wave height. It has been recently proposed that the mean-square slope (mss) derived from global navigation satellite system (GNSS) signals reflected by the sea surface could be a potentially appropriate sea-state descriptor and could be used to make the necessary sea state TB corrections to improve the SSS estimates. This paper presents a preliminary error analysis of the use of reflected GNSS signals for the sea roughness correction and was performed to support the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission; the orbit and parameters for the SMOS instrument were assumed. The accuracy requirement for the retrieved SSS is 0.1 practical salinity units after monthly averaging over 2deg times 2degboxes. In this paper, potential improvements in salinity estimation are hampered mainly by the coarse sampling and by the requirements of the retrieval algorithm, particularly the need for a semiempirical model that relates TB and mss.

Assessing wood-based synthetic natural gas technologies using the SWISS-MARKAL model

Abstract In future, new biomass technologies can gain significant importance in the Swiss energy sector. Therefore, this paper assesses the economic conditions under which new biomass technologies become competitive. The focus of this assessment is on the production of synthetic natural gas (bio-SNG) from wood in a methanation plant. The assessment is conducted with the cost-optimization model SWISS-MARKAL (MARKet ALlocation). SWISS-MARKAL projects future technology investments and provides an integrated analysis of primary, secondary, final and end-use energy in Switzerland. In addition to a reference scenario, the effects of increasing oil and gas prices, the effects of allocating subsidies to the methanation plant and the effects of competition between the methanation plant and a biomass-based Fischer–Tropsch (FT) synthesis are evaluated. Moreover, a sensitivity analysis is performed by varying investment costs of the methanation plant. The results are in favour of bio-SNG in the transportation sector where the synergetic use of bio-SNG and natural gas reduces the dependence on oil imports and the level of CO 2 emissions.

Audio–visual person authentication using lip-motion from orientation maps

This paper describes a new identity authentication technique by a synergetic use of lip-motion and speech. The lip-motion is defined as the distribution of apparent velocities in the movement of brightness patterns in an image and is estimated by computing the velocity components of the structure tensor by 1D processing, in 2D manifolds. Since the velocities are computed without extracting the speaker’s lip-contours, more robust visual features can be obtained in comparison to motion features extracted from lip-contours. The motion estimations are performed in a rectangular lip-region, which affords increased computational efficiency. A person authentication implementation based on lip-movements and speech is presented along with experiments exhibiting a recognition rate of 98%. Besides its value in authentication, the technique can be used naturally to evaluate the “liveness” of someone speaking as it can be used in text-prompted dialogue. The XM2VTS database was used for performance quantification as it is currently the largest publicly available database (≈300 persons) containing both lip-motion and speech. Comparisons with other techniques are presented.

Toward a new generation of satellite surface products?

Despite the abundance and variety of remote sensing measurements, land surface characterization from satellite observations is still very challenging. The links between the three sources of surface information, namely the satellite observations, the in situ measurements, and the land surface model outputs, are complex. Innovative techniques have to be developed to merge these information sources and optimize the use of satellite measurements for better surface products and more predictability. Concepts such as multi‐instrument/multiparameter retrieval algorithms are discussed, as well as the synergetic use of satellite observations, model outputs, and in situ data. The need for careful satellite calibration is stressed, and the scaling problem is emphasized. Recent results are reviewed to indicate what the land surface remote sensing problems are and how they might be attacked. Two concrete applications are presented: an “all weather” retrieval of surface skin temperature from combined microwave and infrared observations and a soil moisture analysis from the merging of multisatellite observations and land surface model outputs. This paper is intended to stimulate debates and collaborations between the land surface modelers and the satellite remote sensing community for the design of the next generation of land surface products.

Dilute magnetic semiconductor nanowires

Semiconductor materials form the basis of modern electronics, communication, data storage and computing technologies. One of today’s challenges for the development of future technologies is the realization of devices that control not only the electron charge, as in present electronics, but also its spin, setting the basis for future spintronics. Spintronics represents the concept of the synergetic and multifunctional use of charge and spin dynamics of electrons, aiming to go beyond the traditional dichotomy of semiconductor electronics and magnetic storage technology. The most direct method to induce spin-polarized electrons into a semiconductor is by introducing appropriate transition-metal or rare-earth dopants producing a dilute magnetic semiconductor (DMS). At the same time the seamless integration of future spintronic devices into nanodevices would require the fabrication of one-dimensional DMS nanostructures in well-defined architectures. In this review we focus on recent advances in the synthesis of DMS nanowires as well discussing the structural, optical and magnetic properties of these materials.

Digital forestry research in China

Digital Forestry as a concept was developed after the Digital Earth program. The Chinese scientists were not only among the pioneers who first proposed the concept of Digital Forestry, but also contributed a lot to the development of Digital Forestry. Digital Forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital Forestry. Under this situation, the experience of Digital Forestry development in China is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital Forestry Construction Scheme. The Project of Digital Forestry Practicability approved by the State Forestry Administration is a major instance in developing Digital Forestry standard and key techniques. By introducing a case study of Digital Forestry, this paper reviews the concept of Digital Forestry, the way turning traditional forestry into Digital Forestry, and the future development of Digital Forestry.

The Antalya 5 December 2002 Storm: Observations and Model Analysis

Abstract In the frame of this work, the storm that occurred on 5 December 2002 in Antalya, located on the southwestern Mediterranean Sea coast of Turkey, is analyzed. More than 230 mm of 24-h-accumulated rainfall have been reported during the event that produced floods in the area. The analysis is based on the results of model simulations with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). Observational data provided by the Tropical Rainfall Measuring Mission (TRMM) sensors (including the Lightning Imaging Sensor and TRMM Microwave Imager), Special Sensor Microwave Imager (SSM/I), Meteosat-7, and Met Office Arrival Time Difference (ATD) lightning network are used for both the comparison with the model results and also for the characterization of the storm. The synergetic use of all of this information was crucial for the description of the event. The maximum of precipitation was associated with the warm and moist air masses driven by a low-level jet over the area and impinging over the orographic barriers. The improvement of representation of the humidity field in the model initial conditions, through a simple technique of humidity adjustment based on satellite rainfall estimates, resulted in an improvement of the prediction of the timing and quantity of the precipitation maxima during the event.

Structure and phase behavior of two-dimensional solids formed at interfaces

Abstract Molecular monolayers adsorbed to solid surfaces such as graphite are distinct from the bulk in their physicochemical properties because of the 2D nature. In most cases, they form a well-defined 2D crystalline solid. We have been investigating such systems of various simple molecules by means of the synergetic use of X-ray diffraction, neutron scattering, and calorimetry. Selected examples illustrate that the reduced dimensionality has important consequences for the structure, dynamics, and phase behavior in the condensed state. In some cases, the similar solid monolayers are formed at the liquid-graphite interfaces, where they also show a rich variety of the structure and phase behavior. For the multicomponent system of those monolayers, mixing behavior is particularly interesting from both the structural and thermodynamic points of view. We also investigated ice crystallization from the solution, where a 2D nature was found in structure in the initial stage of crystallization.