bluuebunny/crossref_metadata_2025 huggingface dataset:
Overview of the 2007 and 2008 campaigns conducted as part of the Greenland Summit Halogen-HOx Experiment (GSHOX)
Authors: Thomas J. L. , Dibb J. E. , Stutz J. , von Glasow R. , Brooks S. , Huey L. G. , Lefer B.
Published: November 2012

Abstract. From 10 May through 17 June 2007 and 6 June through 9 July 2008 intensive sampling campaigns at Summit, Greenland confirmed that active bromine chemistry is occurring in and above the snow pack at the highest part of the Greenland ice sheet (72°36´ N, 38°25´ W and 3.2 km above sea level). Direct measurements found BrO and soluble gas phase Br− mixing ratios in the low pptv range on many days (maxima < 10 pptv). Conversion of up to 200 pg m−3 of gaseous elemental mercury (GEM) to reactive gaseous mercury (RGM) and enhanced OH relative to HO2 plus RO2 confirm that active bromine chemistry is impacting chemical cycles even at such low abundances of reactive bromine species. However, it does not appear that Bry chemistry can fully account for observed perturbations to HOx partitioning, suggesting unknown additional chemical processes may be important in this unique environment, or that our understanding of coupled NOx-HOx-Bry chemistry above sunlit polar snow is incomplete. Rapid transport from the north Atlantic marine boundary layer occasionally caused enhanced BrO at Summit (just two such events observed during the 12 weeks of sampling over the two seasons). In general observed reactive bromine was linked to activation of bromide (Br−) in, and release of reactive bromine from, the snowpack. A coupled snow-atmosphere model simulated observed NO and BrO at Summit during a three day interval when winds were weak. The source of Br− in surface and near surface snow at Summit is not entirely clear, but concentrations were observed to increase when stronger vertical mixing brought free tropospheric air to the surface. Reactive Bry mixing ratios above the snow often increased in the day or two following increases in snow concentration, but this response was not consistent. On seasonal time scales concentrations of Br− in snow and reactive bromine in the air were directly related.
Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde Islands
Authors: Fomba K. W. , Müller K. , van Pinxteren D. , Herrmann H.
Published: November 2012

Abstract. Size-resolved trace metal concentrations of 15 elements in aerosol particles at the Cape Verde Atmospheric Observatory (CVAO) under remote background conditions were investigated through analysis of aerosol samples collected during intensive field studies from January 2007 to November 2011 using total reflection x-ray fluorescence (TXRF). The identification of the main air mass origin that influence remote marine aerosol in the northern tropical Atlantic has been investigated. In total 317 samples were collected. The dataset was analyzed according to the main air mass inflow at the station. We found that remote conditions make up about 45% of the meteorological conditions in a year at CVAO and thus the northern tropical Atlantic. Surprisingly, air masses from North America are often responsible for higher trace metal concentrations in this region. Elements such as Zn, Pb, Cu, Cr, Ni, and V were mostly found in the submicron size fractions while elements with dominant crustal or oceanic origin such as Fe, Ti, Mn, Sr, and Rb, were found in the coarse fractions (>1 μm). The highest metal concentrations especially for Zn (3.23 ng m−3), Cu (0.81 ng m−3), Sr (2.63 ng m−3), and Cr (0.53 ng mm−3), were observed in air masses originating from North America and the concentrations were within the same concentration range to those reported previously in the literature for remote marine aerosols. Fe (12.26 ng m−3), Ti (0.91 ng m−3) and Mn (0.35 ng m−3) showed higher concentrations when air mass came from Europe and the Canary Islands. Pb concentration was low (< 0.20 ng m−3) and did not vary significantly with air mass direction. The low Pb concentration is indicative of the complete phased out of leaded gasoline even in African countries. Crustal enrichment factor values decreased from fine to coarse mode particles with low values (< 4) observed for Fe, Mn, and Rb and high values (> 20) for Zn, Cu, Ni, Cr, Pb, and Se. The observed enrichment of the elements was attributed to crustal, marine, anthropogenic and biogenic sources, as well as long range transport and re-suspension. Zn, Cu and Pb were indicators of anthropogenic activities while Ti, and Sr, were indicators of crustal and marine origin, respectively. Oceanic emissions contributed to most of the Selenium observed. This work provides the first long term size resolved trace metals study for remote tropical northern Atlantic marine aerosols and the dataset could serve as good initiation of yearly flux estimates.
Comparison of N2O5 mixing ratios during NO3Comp 2007 in SAPHIR
Authors: Fuchs H. , Simpson W. R. , Apodaca R. L. , Brauers T. , Cohen R. C. , Crowley J. N. , Dorn H.-P. , Dubé W. P. , Fry J. L. , Häseler R. , Kajii Y. , Kiendler-Scharr A. , Labazan I. , Matsumoto J. , Mentel T. F. , Nakashima Y. , Rohrer F. , Rollins A. W. , Schuster G. , Tillmann R. , Wahner A. , Wooldridge P. J. , Brown S. S.
Published: November 2012

Abstract. N2O5 detection in the atmosphere has been accomplished using techniques which have been developed during the last decade. Most techniques use a heated inlet to thermally decompose N2O5 to NO3, which can be detected by either cavity based absorption at 662 nm or by laser-induced fluorescence. In summer 2007, a large set of instruments, which were capable of measuring NO3 mixing ratios, were simultaneously deployed in the atmosphere simulation chamber SAPHIR in Jülich, Germany. Some of these instruments measured N2O5 mixing ratios either simultaneously or alternatively. Experiments focused on the investigation of potential interferences from, e.g., water vapour or aerosol and on the investigation of the oxidation of biogenic volatile organic compounds by NO3. The comparison of N2O5 mixing ratios shows an excellent agreement between measurements of instruments applying different techniques (3 cavity ring-down (CRDS) instruments, 2 laser-induced fluorescence (LIF) instruments). Datasets are highly correlated as indicated by the square of the linear correlation coefficients, R2, which values were larger than 0.96 for the entire datasets. N2O5 mixing ratios well agree within the combined accuracy of measurements. Slopes of the linear regression range between 0.87 and 1.26 and intercepts are negligible. The most critical aspect of N2O5 measurements by cavity ring-down instruments is the determination of the inlet and filter transmission efficiency. Measurements here show that the N2O5 inlet transmission efficiency can decrease in the presence of high aerosol loads, and that frequent filter/inlet changing is necessary to quantitatively sample N2O5 in some environments. The analysis of data also demonstrates that a general correction for degrading filter transmission is not applicable for all conditions encountered during this campaign. Besides the effect of a gradual degradation of the inlet transmission efficiency aerosol exposure, no other interference for N2O5 measurements is found.
Comparison of AOD between CALIPSO and MODIS: significant differences over major dust and biomass burning regions
Authors: Ma X. , Bartlett K. , Harmon K. , Yu F.
Published: November 2012

Abstract. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) provide, for the first time, global vertical profiles of aerosol optical properties, but further research is needed to evaluate the CALIPSO products. In this study, we employed about 6 yr (2006–2011) of CALIPSO level-3 monthly mean gridded aerosol optical depth (AOD) products (daytime and nighttime), for cloud free conditions, to compare with the MODIS Terra/Aqua level-3 monthly mean AOD dataset for the same time period. While the spatial distribution and seasonal variability of CALIPSO AOD is generally consistent with that of MODIS, CALIPSO is overall lower than MODIS as much more of the CALIPSO data is smaller than 0.1, while more of the MODIS data is greater than 0.1. We will focus on four regions that have large systematic differences: two over dust regions (the Sahara and Northwest China) and two over biomass burning regions (South Africa and South America). It is found that CALIPSO AOD is significantly lower than MODIS AOD over dust regions during the whole time period, with a maximum low bias of 0.3 over the Saharan region, and 0.25 over Northwest China. For biomass burning regions, CALIPSO AOD is significantly higher than MODIS AOD over South Africa, with a maximum high bias of 0.25. Additionally CALIPSO AOD is slightly higher than MODIS AOD over South America for most of the time period, with a few exceptions in 2006, 2007, and 2010, when biomass burning is significantly stronger than during other years. The results in this study indicate that systematic biases of CALIPSO relative to MODIS are closely associated with aerosol types, which vary by location and season. Large differences over dust and biomass burning regions may suggest that assumptions made in satellite retrievals, such as the assumed lidar ratios for CALIPSO retrievals over dust and biomass burning regions, or the surface reflectance information and/or the aerosol model utilized by MODIS algorithm, are not appropriate. Further research is needed to narrow down the exact source of bias in order to improve the satellite retrievals.
Effects of stoichiometry and temperature perturbations on beech leaf litter decomposition, enzyme activities and protein expression
Authors: Keiblinger K. M. , Schneider T. , Roschitzki B. , Schmid E. , Eberl L. , Hämmerle I. , Leitner S. , Richter A. , Wanek W. , Riedel K. , Zechmeister-Boltenstern S.
Published: November 2012

Abstract. Microbes are major players in leaf litter decomposition and therefore advances in the understanding of their control on element cycling are of paramount importance. Our aim was to investigate the influence of leaf litter stoichiometry in terms of carbon (C) : nitrogen (N) : phosphorus (P) ratios on the decomposition processes and to track changes in microbial community structures and functions in response to temperature stress treatments. To elucidate how the stoichiometry of beech leaf litter (Fagus sylvatica L.) and stress treatments interactively affect the microbial decomposition processes, a terrestrial microcosm experiment was conducted. Beech litter from different Austrian sites covering C:N ratios from 39 to 61 and C:P ratios from 666 to 1729 were incubated at 15 °C and 60% moisture for six months. Part of the microcosms were then subjected to severe changes in temperature (+30 °C and −15 °C) to monitor the influence of temperature stress. Extracellular enzyme activities were assayed and respiratory activities measured. A semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass spectrometry; unique spectral counting) was employed to investigate the impact of the applied stress treatments in dependency of litter stoichiometry on structure and function of the decomposing community. In litter with narrow C:nutrient (C:N, C:P) ratios, microbial decomposers were most abundant. Cellulase, chitinase, phosphatase and protease activity decreased after heat and freezing treatments. Decomposer communities and specific functions varied with site, i.e. stoichiometry. The applied stress combined with the respective time of sampling evoked changes of enzyme activities and litter pH. Freezing treatments resulted in a decline in residual plant litter material and increased fungal abundance, indicating slightly accelerated decomposition. Overall, a strong effect of litter stoichiometry on microbial community structures and functions was detected, but decomposition was mainly driven by a combination of the investigated factors. Temperature perturbations resulted in short- to medium-term alterations of microbial functions; especially high temperature treatments blocked decomposing enzymes.
Diversity of cultured photosynthetic flagellates in the northeast Pacific and Arctic Oceans in summer
Authors: Balzano S. , Gourvil P. , Siano R. , Chanoine M. , Marie D. , Lessard S. , Sarno D. , Vaulot D.
Published: November 2012

Abstract. During the MALINA cruise (summer 2009), an extensive effort was undertaken to isolate phytoplankton strains from the northeast (NE) Pacific Ocean, the Bering Strait, the Chukchi Sea, and the Beaufort Sea. In order to characterise the main photosynthetic microorganisms occurring in the Arctic during the summer season, strains were isolated by flow cytometry sorting (FCS) and single cell pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 °C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18 S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18 S rRNA gene sequence similarity), mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas), which was nearly the only phytoplankter recovered within the picoplankton (< 2 μm) size range. Strains of Arctic Micromonas as well as other strains from the same class (Mamiellophyceae) were identified in further detail by sequencing the internal transcribed spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18 S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. Three other Mamiellophyceae strains likely belong to a new genus. Other green algae from the genera Nephroselmis, Chlamydomonas, and Pyramimonas were also isolated, whereas Heterokontophyta included some unidentified Pelagophyceae, Dictyochophyceae (Pedinellales), and Chrysophyceae (Dinobryon faculiferum). Moreover, we isolated some Cryptophyceae (Rhodomonas sp.) as well as a few Prymnesiophyceae and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by scanning electron microscopy (SEM) and 28 S rRNA gene sequencing. Our morphological analyses show that this species possess the diagnostic features of the genus Biecheleria, and the 28 S rRNA gene topology corroborates this affiliation. We thus propose the transfer of W. cincta to the genus Biecheleria and its recombination as Biecheleria cincta.
The distribution of soil phosphorus for global biogeochemical modeling
Authors: Yang X. , Post W. M. , Thornton P. E. , Jain A.
Published: November 2012

Abstract. Phosphorus (P) is a major element required for biological activity in terrestrial ecosystems. Although the total P content in most soils can be large, only a small fraction is available or in an organic form for biological utilization because it is bound either in incompletely weathered mineral particles, adsorbed on mineral surfaces, or, over the time of soil formation, made unavailable by secondary mineral formation (occluded). In order to adequately represent phosphorus availability in global biogeochemistry-climate models, a representation of the amount and form of P in soils globally is required. We develop an approach that builds on existing knowledge of soil P processes and databases of parent material and soil P measurements to provide spatially explicit estimates of different forms of soil P on the global scale. We assembled data on the various forms of phosphorus in soils globally, chronosequence information, and several global spatial databases to develop a map of total soil P and the distribution among mineral bound, labile, organic, occluded, and secondary P forms in soils globally. The amount of P, to 50 cm soil depth, in soil labile, organic, occluded, and secondary pools is 3.5 ± 3, 8.7 ± 6, 13.2 ± 9, and 3.3 ± 2 Pg P respectively. The amount in soil mineral particles to the same depth is estimated at 12.5 ± 9 Pg P for a global soil total of 41.2 ± 20 Pg P. The large uncertainty in our estimates reflects our limited understanding of the processes controlling soil P transformations during pedogenesis and lack of measurements of soil P. In spite of the large uncertainty, the estimated global spatial variation and distribution of different soil P forms presented in this study will be useful for global biogeochemistry models that include P as a limiting element in biological production by providing initial estimates of the available soil P for plant uptake and microbial utilization.
Future Flows Climate: an ensemble of 1-km climate change projections for hydrological application in Great Britain
Authors: Prudhomme C. , Dadson S. , Morris D. , Williamson J. , Goodsell G. , Crooks S. , Boelee L. , Davies H. , Buys G. , Lafon T. , Watts G.
Published: November 2012

Abstract. The dataset Future Flows Climate was developed as part of the project ''Future Flows and Groundwater Levels'' to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications, and to enable climate change uncertainty and climate variability to be accounted for in the assessment of their possible impacts on the environment. Future Flows Climate is derived from the Hadley Centre's ensemble projection HadRM3-PPE that is part of the basis of UKCP09 and includes projections in available precipitation (water available to hydrological processes after snow and ice storages have been accounted for) and potential evapotranspiration. It corresponds to an 11-member ensemble of transient projections from January 1950 to December 2098, each a single realisation from a different variant of HadRM3. Data are provided on a 1-km grid over the HadRM3 land areas at a daily (available precipitation) and monthly (PE) time step as netCDF files. Because systematic biases in temperature and precipitation were found between HadRM3-PPE and gridded temperature and precipitation observations for the 1962–1991 period, a monthly bias correction procedure was undertaken, based on a linear correction for temperature and a quantile-mapping correction (using the gamma distribution) for precipitation followed by a spatial downscaling. Available precipitation was derived from the bias-corrected precipitation and temperature time series using a simple elevation-dependant snow-melt model. Potential evapotranspiration time series were calculated for each month using the FAO-56 Penman-Monteith equations and bias-corrected temperature, cloud cover, relative humidity and wind speed from HadRM3-PPE along with latitude of the grid and the day of the year. Future Flows Climate is freely available for non-commercial use under certain licensing conditions. It is the dataset used to generate Future Flows Hydrology, an ensemble of transient projections of daily river flow and monthly groundwater time series for representative river basins and boreholes in Great Britain. doi:10.5285/bad1514f-119e-44a4-8e1e-442735bb9797.
Correcting the radar rainfall forcing of a hydrological model with data assimilation: application to flood forecasting in the Lez catchment in Southern France
Authors: Harader E. , Borrell-Estupina V. , Ricci S. , Coustau M. , Thual O. , Piacentini A. , Bouvier C.
Published: November 2012

Abstract. The present study explores the application of a data assimilation (DA) procedure to correct the radar rainfall inputs of an event-based, distributed, parsimonious hydrological model. An extended Kalman filter algorithm was built on top of a rainfall-runoff model in order to assimilate discharge observations at the catchment outlet. This work focuses primarily on the uncertainty in the rainfall data and considers this as the principal source of error in the simulated discharges, neglecting simplifications in the hydrological model structure and poor knowledge of catchment physics. The study site is the 114 km2 Lez catchment near Montpellier, France. This catchment is subject to heavy orographic rainfall and characterised by a karstic geology, leading to flash flooding events. The hydrological model uses a derived version of the SCS method, combined with a Lag and Route transfer function. Because the radar rainfall input to the model depends on geographical features and cloud structures, it is particularly uncertain and results in significant errors in the simulated discharges. This study seeks to demonstrate that a simple DA algorithm is capable of rendering radar rainfall suitable for hydrological forecasting. To test this hypothesis, the DA analysis was applied to estimate a constant hyetograph correction to each of 19 flood events. The analysis was carried in two different modes: by assimilating observations at all available time steps, referred to here as reanalysis mode, and by using only observations up to 3 h before the flood peak to mimic an operational environment, referred to as pseudo-forecast mode. In reanalysis mode, the resulting correction of the radar rainfall data was then compared to the mean field bias (MFB), a corrective coefficient determined using rain gauge measurements. It was shown that the radar rainfall corrected using DA leads to improved discharge simulations and Nash-Sutcliffe efficiency criteria compared to the MFB correction. In pseudo-forecast mode, the reduction of the uncertainty in the rainfall data leads to a reduction of the error in the simulated discharge, but uncertainty from the model parameterisation diminishes data assimilation efficiency. While the DA algorithm used is this study is effective in correcting uncertain radar rainfall, model uncertainty remains an important challenge for flood forecasting within the Lez catchment.
Anterior Segment Complications after Phacovitrectomy in Diabetic and Nondiabetic Patients
Authors: Pinarci Eylem Yaman , Bayar Sezin Akca , Sizmaz Selcuk , Yesilirmak Nilufer , Akkoyun Imren , Yilmaz Gursel
Published: November 2012

Purpose.

To evaluate early and late postoperative anterior segment complications of phacovitrectomy and foldable intraocular lens (IOL) implantation in eyes with cataract and coexisting vitreoretinal disease in diabetic and nondiabetic patients.

Setting.

Department of Ophthalmology, Baskent University Hospital, Ankara, Turkey.

Methods.

The records of 189 consecutive patients with cataract and posterior segment pathology necessitating phacovitrectomy were retrospectively analyzed. Patient profile, indications for surgery, preoperative findings, intraoperative and postoperative course, and postoperative outcome were evaluated. Phacoemulsification was performed through a clear corneal incision with IOL implantation prior to 23-G pars plana vitrectomy.

Results.

There were 97 (51.3%) diabetic and 92 (48.6%) nondiabetic patients. The most common indications for surgery were vitreous hemorrhage (57; 58.7%), tractional detachment (35; 36%), and premacular hemorrhage (5; 5.1%) in diabetic patients, and rhegmatogenous retinal detachment (40; 43.4%), macular hole (22; 23.9%), epiretinal membrane (20; 21.7%), and vitreomacular traction (10; 10.8%) in nondiabetic patients. Early (within 4 weeks) postoperative complications included elevation of intraocular pressure, fibrinous uveitis, corneal edema, and development of posterior synechia. Long-term (after 4 weeks) complications included migration of silicone oil into the anterior chamber, posterior capsule opacification, and decentered IOL. The ratio of fibrinous uveitis, posterior synechia, and posterior capsule opacification was found higher in the diabetic group (all p<0.05).

Conclusions.

Combined vitreoretinal surgery and phacoemulsification is safe and effective in treating vitreoretinal abnormalities coexisting with cataract in diabetic and nondiabetic patients. Diabetic patients should be monitored more carefully for fibrinous uveitis and posterior synechia in the early postoperative period and for posterior capsular opacification in the late postoperative period.
The Accuracy of Ultrasound Volume Flow Measurements in the Complex Flow Setting of a Forearm Vascular Access
Authors: Van Canneyt Koen , Swillens Abigail , Lovstakken Lasse , Antiga Luca , Verdonck Pascal , Segers Patrick
Published: November 2012

Purpose

Maturation of an arterio-venous fistula (AVF) frequently fails, with low post-operative fistula flow as a prognostic marker for this event. As pulsed wave Doppler (PWD) is commonly used to assess volume flow, we studied the accuracy of this measurement in the setting of a radio-cephalic AVF.

Methods

As in-vivo validation of fistula flow measurements is cumbersome, we performed simulations, integrating computational fluid dynamics with an ultrasound (US) simulator. Flow in the arm was calculated, based on a patient-specific model of the arm vasculature pre and post AVF creation. Raw ultrasound signals were subsequently simulated, from which Doppler spectra were calculated in both a proximal and a distal location.

Results

The velocity component in the direction of the PWD-US beam (vPWD), in a centered, small, sample volume, can be captured accurately using PWD spectrum mean-tracking (maximum bias [mB] 8.1%). However, when deriving flow rate from these measurements, a high degree of inaccuracy occurs. First, the angle-correction of vPWD towards the velocity along the axis of the vessel is largely influenced by the radial velocity components in the complex flow field (mB=16.3%). Second, the largest error is introduced when transferring the centerline velocity to the cross-sectional mean velocity without any knowledge of the flow profile (mB=97.7%).

Conclusions

In the setting of a forearm AVF, flow estimates based on PWD are hampered by the complex flow patterns. Overall, flow estimation based on centerline measurement, analyzed by mean-tracking of the RF-spectral estimates, under the assumption of a parabolic flow profile, appeared to provide the most reasonable values.
Decentralized RBFNN Type-2 Fuzzy Sliding Mode Controller for Robot Manipulator Driven by Artificial Muscles
Authors: Amar Rezoug , Mustapha Hamerlain , Mohamed Tadjine
Published: November 2012

In the few last years, investigations in neural networks, fuzzy systems and their combinations become attractive research areas for modeling and controlling of uncertain systems. In this paper, we propose a new robust controller based on the integration of a Radial Base Function Neural Network (RBFNN) and an Interval Type-2 Fuzzy Logic (IT2FLC) for robot manipulator actuated by pneumatic artificial muscles (PAM). The proposed approach was synthesized for each joint using Sliding Mode Control (SMC) and named Radial Base Function Neural Network Type-2 Fuzzy Sliding Mode Control (RBFT2FSMC). Several objectives can be accomplished using this control scheme such as: avoiding difficult modeling, attenuating the chattering effect of the SMC, reducing the rules number of the fuzzy control, guaranteeing the stability and the robustness of the system, and finally handling the uncertainties of the system. The proposed control approach is synthesized and the stability of the robot using this controller was analyzed using Lyapunov theory. In order to demonstrate the efficiency of the RBFT2FSMC compared to other control technique, simulations experiments were performed using linear model with parameters uncertainties obtained after identification stage. Results show the superiority of the proposed approach compared to RBFNN Type-1 Fuzzy SMC. Finally, an experimental study of the proposed approach was presented using 2-DOF robot.
Multi-Mode Radar Target Detection and Recognition Using Neural Networks
Authors: Briones Janette C. , Flores Benjamin , Cruz-Cano Raul
Published: November 2012

In typical radar systems, the process of recognizing a target requires human involvement. This human element makes radar systems not fully reliable due to unstable performance that varies between operators. This paper describes an intelligent radar system which addresses this problem in a border surveillance environment. The proposed radar system is capable of automatically detecting and then classifying different targets using an artificial neural network trained with the Levenberg-Marquardt algorithm. The training and test sets presented to the neural network are composed by high-resolution Inverse Synthetic Aperture Radar pictures obtained by the radar's detection module. Simulation results show that the intelligent radar system can reliably detect and distinguish the different objectives. Moreover, the radar system can outperform human operators and another radar system that deals with similar objectives. These results indicate that future intelligent systems can potentially replace human radar operators in this critical security setting.
Voice Command Recognition in Multirobot Systems: Information Fusion
Authors: Miček Juraj , Hyben Martin , Frátrik Milan , Púchyová Jana
Published: November 2012

Recent Multirobot systems (MRS) are moving from theoretical considerations and from development and research centres to the area of practical applications. The solutions to real practical problems bring new challenges which are derived from actual requirements, while they are also interesting from theoretical point of view. One of the interesting areas of investigation is the problem of distributed data processing by limited computing and communication performance of individual components in MRS.

In this article, the authors try to demonstrate, using a simple example, the possibilities of distributed solution of classification tasks.

Such questions as:

– To what extent it is appropriate to distribute the tasks among individual elements of the system and to what extent to minimalize the requests on the communication subsystem? – Is it more appropriate, in the design concept of distributed data processing, to use a data fusion system, features fusion or decision fusion? are not universally solvable.

Therefore, we refrain from the analytical analysis and the choice of appropriate level of information fusion, but in four different scenarios we focus on solving ‘voice command recognition’ – we would like to show the advantages and disadvantages of individual approaches. The experiments described and the results achieved are based on simulation experiments and verified by experimental and demonstrative MRS.
Insights into the Capabilities of Tactile-Foot Perception
Authors: Velázquez Ramiro , Bazán Omar , Varona Jorge , Delgado-Mata Carlos , Gutiérrez Carlos A.
Published: November 2012

This paper presents a novel wearable interface for the foot: a shoe-integrated tactile display that enables users to obtain information through the sense of touch via their feet. A 16-point array of actuators stimulates the sole of the foot by inducing different vibration frequencies. A series of experiments were conducted with 20 sighted and 5 blind voluntary subjects to evaluate the role of tactile perception by the human foot and the tactile sensitivity of the plantar surface. Tests evaluated the perception of simple shapes, patterns and directional instructions. The results showed that some information is discriminable and that tactile-foot stimulation could be used for a wide number of applications in human-machine interaction. Furthermore, the results also suggested that the blind perform better in some key tasks and support the feasibility of footwear providing tactile feedback for situational awareness, mobility and the navigation assistance of the blind.
Estimating Productivity of Software Development Using the Total Factor Productivity Approach
Authors: Ondrej Machek , Jiri Hnilica , Jan Hejda
Published: November 2012

The design, control and optimization of software engineering processes generally require the determination of performance measures such as efficiency or productivity. However, the definition and measurement of productivity is often inaccurate and differs from one method to another. On the other hand, economic theory offers a well-grounded tool of productivity measurement. In this article, we propose a model of process productivity measurement based on the total factor productivity (TFP) approach commonly used in economics. In the first part of the article, we define productivity and its measurement. We also discuss the major data issues which have to be taken into consideration. Consequently, we apply the TFP approach in the domain of software engineering and we propose a TFP model of productivity assessment.
Efficiency in Brazilian Refineries under Different DEA Technologies
Authors: Francisco Claudia Aparecida Cavalheiro , de Almeida Mariana Rodrigues , da Silva Djalma Ribeiro
Published: November 2012

This paper aims to assess the environmental efficiency of refineries in the public sector with emphasis on generated effluents and water consumption in the production process. In order to conduct this research, the addressed method was quantitative with a qualitative approach to the environmental aspects of controllable and uncontrollable variables implemented in two classical models of Data Envelopment Analysis (DEA), considering only desirable outputs and two DEA models which include undesirable outputs. The sample consists of ten refineries considering the following as input variables: idleness percentage of the operating plant, the amount of water consumed; and the following as outputs: refinery production volume and generated effluents, desirable and undesirable, respectively, besides the uncontrollable variable, the refinery age. With the comparison result between the models, we observed the clear importance of the environmental variable for a more realistic analysis of the production process.
Docking System Design and Self-Assembly Control of Distributed Swarm Flying Robots
Authors: Wei Hongxing , Li Ning , Tao Yong , Chen Youdong , Tan Jindong
Published: November 2012

This paper presents a novel docking system design and the distributed self-assembly control strategy for a Distributed Swarm Flying Robot (DSFR). The DSFR is a swarm robot comprising many identical robot modules that are able to move on the ground, dock with each other and fly coordinately once self-assembled into a robotic structure. A generalized adjacency matrix method is proposed to describe the configurations of robotic structures. Based on the docking system and the adjacency matrix, experiments are performed to demonstrate and verify the self-assembly control strategy.
Robust Corner Detection by Image-Based Direct Curvature Field Estimation for Mobile Robot Navigation
Authors: Kim Sungho
Published: November 2012

In this paper, a novel corner detection method is presented, to extract geometrically important corners for robot applications, such as indoor mobile robot navigation or manipulation. Intensity-based corner detectors, such as the Harris corner, can detect corners in noisy environments, but have inaccurate corner positions and miss the corners of obtuse angles. Edge-based corner detectors, such as the Curvature Scale Space, can detect structural corners, but show unstable corner detection due to incomplete edge detection in noisy environments. The proposed image-based direct curvature estimation can overcome limitations in both the inaccurate structural corner detection of the Harris corner detector (intensity-based) and the unstable corner detection of the Curvature Scale Space, caused by incomplete edge detection. Various experimental results validate the robustness of the proposed method.
The Role of Social Software for Customer Co-Creation: Does it Change the Practice for Innovation?
Authors: Martini Antonella , Massa Silvia , Testa Stefania
Published: November 2012

This article investigates a customer co-creation project at the front end of the innovation process at a large well-known Italian food manufacturer, which is enabled by social media. The purpose is to shed light on the role of such technology in transforming the characteristics of the FEI, in terms of boundaries and knowledge distance: what type of innovation ideas – exploratory or exploitative – does the practice enable? Could social media be used to manage the explore-exploit paradox, thus transforming the practice into an ambidextrous one?

The empirical analysis highlights that the investigated customer co-creation practice has evolved from the initial stage of idea exploitation to a stage in which both exploitation and exploration are simultaneously accomplished.
How to Measure the ET-ET Construct for Ambidexterity Comparative Analysis of Measures and New Measurement Proposal
Authors: Martini Antonella , Aloini Davide , Dulmin Riccardo , Mininno Valeria , Neirotti Paolo
Published: November 2012

Although there is broad agreement that ambidexterity somehow relates to the simultaneous pursuit of exploratory and exploitative activities, a lack of conceptual clarity exists regarding the extent to which ambidexterity concerns matching the magnitude (BD) of exploration and exploitation on a relative basis, or concerns the combined magnitude (CD) of both activities. This fragmentation has inspired different operationalization of the construct and limited its usefulness, both for scholars and practitioners, since interpretations, comparisons and analysis between cross studies or research have become more difficult. This article proposes and tests an alternative measure of ambidexterity, which attempts to simultaneously and explicitly include in an overall index both the combined (CD) and the balanced dimension (BD).
Sustainability in Healthcare: Combining Organizational and Architectural Levers
Authors: Pinzone Marta , Lettieri Emanuele , Masella Cristina
Published: November 2012

Healthcare has been progressively required to improve its environmental performance as have other industries in recent years. In this regard, many new healthcare facilities have been built worldwide adopting sustainability-oriented approaches. However, results have been limited from an ecological and economic perspective, and many projects have rapidly become failures and then been abandoned.

A large part of these failures is grounded in the misalignment between the adoption of eco-friendly facilities and greening technologies and the persistence of outdated practices, mindsets and behaviours among healthcare professionals.

This study aims at furthering the current debate among leading practitioners and scholars of engineering business management about the combination of organizational and architectural levers for improving the sustainability of healthcare delivery.

By taking a socio-technical systems perspective, we developed a literature-grounded framework and relative propositions with respect to the improvement of sustainability-related performances in hospitals through the combination of organizational and architectural levers. Ten levers and their mutual relationships have been identified and described.
MEMRI study ‐ feedback of MEMS dosing history improves adherence to long‐term HAART: adherence is associated with incidence of ‘blips’ in viral load
Authors: White D , Aghar S , Taylor S , Cook R , Hickinbottom G , Berry A , Robertson C , Horne R , Cooper V , Lange A , Vrijens B
Published: November 2012

In routine clinical care we investigated the effect on adherence to HAART of feedback to each patient of graphical plots highlighting recent errors in their dosing history, as compiled electronically using MEMS®. Patients established on HAART were randomised to receive either active feedback of recent dosing errors (Group A) at clinic visits, or to serve as controls (no feedback) (Group B). After 12 months the control group were un‐blinded and given feedback for a further 6 months. Questionnaires were completed in the waiting room for adherence (GEEMA), Necessity/Concerns, Intrusiveness, Self‐efficacy and Conscientiousness (baseline only). Those declining/excluded from using MEMS were invited to complete baseline questionnaires (Group C). Adherence was estimated from MEMS data as the average proportion of days with at least the prescribed number of doses taken between successive appointments. Drug Holidays (DH) were defined as 3 or more consecutive days without dosing. Of a cohort of 727 ~270 were approached. 180 were randomised. 147 had evaluable MEMS data (68 Group B: 79 Group A). 85 were in Group C (questionnaires only). Baseline characteristics were similar between Group A and B. Group C had a less common past history of AIDS. There was no significant difference in baseline conscientiousness between Groups A and B. Missed doses were much more likely at weekends than weekdays (OR=1.25; [1.15–1.35]). Those taking <95% of prescribed doses during the first interval between visits were defined as poor adherers, which included 69 patients (49%). Their average baseline adherence was 78%. In Group A, average adherence increased (p=0.001) to 90% after the first feedback session, while in Group B average adherence remained stable (p=0.405). In Group B, after un‐blinding and start of feedback, adherence increased to 93%. Patients in Group B were significantly less likely to bring back their MEMS for reading at each appointment (p=0.031). The incidence of viral load ‘blips’ (>50 copies/ml) was significantly increased by DH (p=0.007), frequency of DH (p=0.016), length of DH (p=0.005), and missed doses during the 4 weeks before attendance (p=0.001). Feedback of electronically compiled dosing history data improves adherence to HAART treatment and appears to be an effective intervention for reducing the incidence of viral load ‘blips’. Further results including analysis of the questionnaires will be presented.
Impact of comorbidities on HIV medication persistence: a retrospective database study using US claims data
Authors: Maiese E , Malmenäs M , Atkinson M
Published: November 2012

Medication persistence (MP) is important in HIV management as lifelong HIV therapy is needed and discontinuation of HIV therapy could represent a permanent loss of therapeutic options. Many factors have been shown to decrease HIV treatment persistence; however, the evidence for comorbidities has been conflicting [1,2]. This study was conducted to further explore the impact of comorbidities on HIV MP. Data from the IMS PharMetrics claims database was used. To be included, patients had to 1) be 18 years of age or older; 2) have a diagnosis code for HIV during the study period (Jan 2006–Sep 2011); 3) have a claim for at least one HIV medication during the index period (Jan 2007–Sep 2010); and 4) have continuous enrollment 12 months before and after the index date. Patients could not have a diagnosis code for pregnancy during the study period or a claim for an HIV medication during the 12 months prior to the index date. The index date was the date of the first claim of an HIV medication during the index period and all HIV medications recorded on the index date were included as the HIV index regimen. MP was defined as time to discontinuation of the HIV index therapy using a 90‐day grace period. Variables statistically significant (p<0.05) in bivariate testing were included in a Cox proportional hazard model to adjust for confounding. Gender, index year, insurance provider type, number of HIV pills/day, and number of comorbidities were included in the final Cox model. A total of 3,057 patients were included in the analysis. The mean age was 43.9 yrs and 76.3% were male. The average MP was 315 days (min 92–max 365). In the Cox model, patients with 1, 2 and≥3 comorbidities had a 6% (p=0.528), 28% (p=0.014) and 31% (p=0.002), respectively, higher risk of discontinuing HIV index regimens than patients with no comorbidities. Additionally, females had a 29% (p<0.001) higher risk of discontinuing HIV index regimens than males. The analysis supports prior evidence that comorbidities decrease HIV MP. This observation may be the result of patients switching HIV medications due to drug‐drug interactions from polypharmacy for managing HIV and comorbidities or due to HIV medication adverse effects. Further research should address the impact of specific HIV regimens on HIV MP among patients with comorbidities and potential differences between genders.
Does a simplified regimen give a better adherence, treatment satisfaction, and quality of life?
Authors: Langebeek N , Sprengers H , Gisolf E , Richter C , Sprangers M , Reiss P , Nieuwkerk P
Published: November 2012

Background

Adherence to treatment is the key to the success of combination antiretroviral therapy (cART) for HIV infection. It is generally assumed that simplification of cART will lead to better adherence, higher treatment satisfaction, and quality of life (QoL), but randomized studies demonstrating such advantages of simplified regimens are scarce.

Methods

Antiretroviral‐naïve patients who achieved viral load <50 c/ml in two consecutive samples between 12–24 weeks after commencing induction therapy with bid lopinavir/ritonavir (LPV/r) and fixed‐dose combination AZT/3TC (Combivir®) were randomly assigned to either continue LPV/r/Combivir® or switch to simplified therapy with bid fixed‐dose AZT/3TC/abacavir (Trizivir®). Both arms yielded similar antiviral efficacy after 48 weeks as reported previously [1]. Patients completed standardized questionnaires on adherence (Simplified Medication Adherence Questionnaire (SMAQ)), treatment satisfaction (HIVTSQ) and QoL (MOS‐HIV) at randomization and at weeks 48, 72 and 96. Adherence data were analyzed using generalized estimating equations, and satisfaction and QoL using mixed linear models.

Results

Patients in the Trizivir®‐group (n=30) tended to skip fewer doses both during the preceding 7 days (p=0.055) and during the preceding weekend (p=0.09) than patients in the LPV/r‐group (n=20). Moreover, patients in the Trizivir®‐group found their regimen significantly more convenient (p=0.022) than patients in the LPV/r‐group. However, patients in the LPV/r‐group reported a better QoL than patients in the Trizivir®‐group in the domains measuring cognitive functioning (p=0.003), energy/fatigue (p=0.046) and social functioning (p=0.074).

Conclusions

In this randomized trial simplification of therapy to fixed‐dose Trizivir® was perceived to be more convenient, and tended to result in improved adherence, but at the expense of a lower level of QoL. Our findings suggest that the choice for simplified regimens should be individualized and may involve a trade‐off between convenience and QoL.