bluuebunny/crossref_metadata_2025 huggingface dataset:
CO source contribution analysis for California during ARCTAS-CARB
Authors: Pfister G. G. , Avise J. , Wiedinmyer C. , Edwards D. P. , Emmons L. K. , Diskin G. D. , Podolske J. , Wisthaler A.
Published: August 2011

Abstract. Air pollution is of concern in many parts of California and is impacted by both local emissions and also by pollution inflow from the North Pacific Ocean. In this study, we use the regional chemical transport model WRF-Chem V3.2 together with the global Model for OZone and Related Chemical Tracers to examine the CO budget over California. We include model CO tracers for different emission sources in the models, which allow estimation of the relative importance of local sources versus pollution inflow on the distribution of CO at the surface and in the free troposphere. The focus of our study is on the 15 June–15 July 2008 time period, which coincides with the aircraft deployment of the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission over California. Model simulations are evaluated using these aircraft observations as well as satellite retrievals and surface observations of CO. Evaluation results show that the model overall predicts the observed CO fields well, but points towards an underestimate of CO from the fires in Northern California, which had a strong influence during the study period, and towards a slight overestimate of CO from pollution inflow and local anthropogenic sources. The analysis of the CO budget over California reveals that inflow of CO explains on average 99 ± 11 ppbV of surface CO during the study period, compared to 61 ± 95 ppbV for local anthropogenic direct emissions of CO and 84 ± 194 ppbV for fires. In the free troposphere, the average CO contributions are estimated as 96 ± 7 ppbV for CO inflow, 8 ± 9 ppbV for CO from local anthropogenic sources and 18 ± 13 ppbV for CO from fires. Accounting for the low bias in the CO fire emission inventory, the fire impact during the study period might have been up to a factor 4 higher than the given estimates.
Projections of UV radiation changes in the 21st century: impact of ozone recovery and cloud effects
Authors: Bais A. F. , Tourpali K. , Kazantzidis A. , Akiyoshi H. , Bekki S. , Braesicke P. , Chipperfield M. P. , Dameris M. , Eyring V. , Garny H. , Iachetti D. , Jöckel P. , Kubin A. , Langematz U. , Mancini E. , Michou M. , Morgenstern O. , Nakamura T. , Newman P. A. , Pitari G. , Plummer D. A. , Rozanov E. , Shepherd T. G. , Shibata K. , Tian W. , Yamashita Y.
Published: August 2011

Abstract. Monthly averaged surface erythemal solar irradiance (UV-Ery) for local noon from 1960 to 2100 has been derived using radiative transfer calculations and projections of ozone, temperature and cloud change from 14 chemistry climate models (CCM), as part of the CCMVal-2 activity of SPARC. Our calculations show the influence of ozone depletion and recovery on erythemal irradiance. In addition, we investigate UV-Ery changes caused by climate change due to increasing greenhouse gas concentrations. The latter include effects of both stratospheric ozone and cloud changes. The derived estimates provide a global picture of the likely changes in erythemal irradiance during the 21st century. Uncertainties arise from the assumed scenarios, different parameterizations – particularly of cloud effects on UV-Ery – and the spread in the CCM projections. The calculations suggest that relative to 1980, annually mean UV-Ery in the 2090s will be on average ~12 % lower at high latitudes in both hemispheres, ~3 % lower at mid latitudes, and marginally higher (~1 %) in the tropics. The largest reduction (~16 %) is projected for Antarctica in October. Cloud effects are responsible for 2–3 % of the reduction in UV-Ery at high latitudes, but they slightly moderate it at mid-latitudes (~1 %). The year of return of erythemal irradiance to values of certain milestones (1965 and 1980) depends largely on the return of column ozone to the corresponding levels and is associated with large uncertainties mainly due to the spread of the model projections. The inclusion of cloud effects in the calculations has only a small effect of the return years. At mid and high latitudes, changes in clouds and stratospheric ozone transport by global circulation changes due to greenhouse gases will sustain the erythemal irradiance at levels below those in 1965, despite the removal of ozone depleting substances. At northern high latitudes (60°–90°), the projected decreases in cloud transmittance towards the end of the 21st century will reduce the yearly average surface erythemal irradiance by ~5 % with respect to the 1960s.
High resolution modelling of aerosol dispersion regimes during the CAPITOUL field experiment: from regional to local scale interactions
Authors: Aouizerats B. , Tulet P. , Pigeon G. , Masson V. , Gomes L.
Published: August 2011

Abstract. High resolution simulation of complex aerosol particle evolution and gaseous chemistry over an atmospheric urban area is of great interest for understanding air quality and processes. In this context, the CAPITOUL (Canopy and Aerosol Particle Interactions in the Toulouse Urban Layer) field experiment aims at a better understanding of the interactions between the urban dynamics and the aerosol plumes. During a two-day Intensive Observational Period, a numerical model experiment was set up to reproduce the spatial distribution of specific particle pollutants, from the regional scales and the interactions between different cities, to the local scales with specific turbulent structures. Observations show that local dynamics depends on the day-regime, and may lead to different mesoscale dynamical structures. This study focuses on reproducing these fine scale dynamical structures, and investigate the impact on the aerosol plume dispersion. The 500-m resolution simulation manages to reproduce convective rolls at local scale, which concentrate most of the aerosol particles and can locally affect the pollutant dispersion and air quality.
Contributions of regional and intercontinental transport to surface ozone in the Tokyo area
Authors: Yoshitomi M. , Wild O. , Akimoto H.
Published: August 2011

Abstract. Japan lies downwind of the Asian continent and for much of the year air quality is directly influenced by emissions of ozone precursors over these heavily-populated and rapidly-industrializing regions. This study examines the extent to which oxidant transport from regional and distant anthropogenic sources influences air quality in Japan in springtime, when these contributions are largest. We find that European and North American contributions to surface ozone over Japan in spring are persistent, averaging 3.5±1.1 ppb and 2.8±0.5 ppb respectively, and are greatest in cold continental outflow conditions following the passage of cold fronts. Contributions from China are larger, 4.0±2.8 ppb, and more variable, as expected for a closer source region, and are generally highest near cold fronts preceding the influence of more distant sources. The stratosphere provides a varying but ever-present background of ozone of about 11.2±2.5 ppb during spring. Local sources over Japan and Korea have a relatively small impact on mean ozone, 2.4±7.6 ppb, but this masks a strong diurnal signal, and local sources clearly dominate during episodes of high daytime ozone. By examining the meteorological mechanisms that favour transport from different source regions, we demonstrate that while maximum foreign influence generally does not occur at the same time as the greatest buildup of oxidants from local sources, it retains a significant influence under these conditions. It is thus clear that while meteorological boundaries provide some protection from foreign influence during oxidant outbreaks in Tokyo, these distant sources still make a substantial contribution to exceedance of the Japanese ozone air quality standard in springtime.
Potential evaporation trends over land between 1983–2008: driven by radiative fluxes or vapour-pressure deficit?
Authors: Matsoukas C. , Benas N. , Hatzianastassiou N. , Pavlakis K. G. , Kanakidou M. , Vardavas I.
Published: August 2011

Abstract. We model the Penman potential evaporation (PE) over all land areas of the globe for the 25-yr period 1983–2008, relying on radiation transfer models (RTMs) for the shortwave and longwave fluxes. Penman's PE is determined by two factors: available energy for evaporation and ground to atmosphere vapour transfer. Input to the PE model and RTMs comprises satellite cloud and aerosol data, as well as data from reanalyses. PE is closely linked to pan evaporation, whose trends have sparked controversy in the community, since the factors responsible for the observed pan evaporation trends are not determined with consensus. Our particular interest is the temporal evolution of PE, and the provided insight to the observed trends of pan evaporation. We examine the decadal trends of PE and various related physical quantities, such as net solar flux, net longwave flux, water vapour saturation deficit and wind speed. Our findings are the following: Global warming has led to a larger water vapour saturation deficit. The periods 1983–1989, 1990–1999, and 2000–2008 were characterised by decreasing, increasing, and slightly decreasing PE, respectively. In these last 25 yr, global dimming/brightening cycles generally increased the available energy for evaporation. PE trends seem to follow more closely the trends of energy availability than the trends of the atmospheric capability for vapour transfer, at most locations on the globe, with trends in the Northern hemisphere significantly larger than in the Southern. These results support the hypothesis that global potential evaporation trends are attributed primarily to secular changes in the radiation fluxes, and secondarily to vapour transfer considerations.
HOCl and Cl2 observations in marine air
Authors: Lawler M. J. , Sander R. , Carpenter L. J. , Lee J. D. , von Glasow R. , Sommariva R. , Saltzman E. S.
Published: August 2011

Abstract. Cl atoms in the marine atmosphere may significantly impact the lifetimes of methane and other hydrocarbons. However, the existing estimates of Cl atom levels in marine air are based on indirect evidence. Here we present measurements of the Cl precursors HOCl and Cl2 in the marine boundary layer during June of 2009 at the Cape Verde Atmospheric Observatory in the eastern tropical Atlantic. These are the first measurements of tropospheric HOCl. HOCl and Cl2 levels were low in air with open ocean back trajectories, with maximum levels always below 60 and 10 ppt (pmol/mol), respectively. In air with trajectories originating over Europe, HOCl and Cl2 levels were higher, with HOCl maxima exceeding 100 ppt each day and Cl2 reaching up to 35 ppt. The increased Cl cycling associated with long distance pollutant transport over the oceans likely impacts a wide geographic area and represents a mechanism by which human activities have increased the reactivity of the marine atmosphere. Data-constrained model simulations indicate that Cl atoms account for approximately 15 % of methane destruction on days when aged polluted air arrives at the site. A photochemical model does not adequately simulate the observed abundances of HOCl and Cl2, raising the possibility of an unknown HOCl source.
Development of a fast, urban chemistry metamodel for inclusion in global models
Authors: Cohen J. B. , Prinn R. G.
Published: August 2011

Abstract. A reduced form metamodel has been produced to simulate the effects of physical, chemical, and meteorological processing of highly reactive trace species in urban areas, which is capable of efficiently simulating the urban concentration, surface deposition, and net export flux of these species. A polynomial chaos expansion and the probabilistic collocation method have been used to develop the metamodel, and its coefficients, so that it is applicable under a broad range of present-day and future conditions. The inputs upon which this metamodel have been formed are based on a combination of physical properties (average temperature, diurnal temperature range, date, and latitude), anthropogenic properties (patterns and amounts of emissions), and the nature of the surrounding environment (background concentrations of species). The metamodel development involved using probability distribution functions (PDFs) of the inputs to run a detailed parent chemical and physical model, the Comprehensive Air Quality Model with Extensions (CAMx), thousands of times. Outputs from these runs were used in turn to both determine the coefficients of and test the precision of the metamodel, as compared with the detailed parent model. It was determined that the deviations between the metamodel and the parent mode for many important species (O3, CO, NOx, and black carbon (BC)) were found to have a weighted RMS error less than 10 % in all cases, with many of the specific cases having a weighted RMS error less than 1 %. Some of the other important species (VOCs, PAN, OC, and sulfate aerosol) usually have their weighted RMS error less than 10 % as well, except for a small number of cases. In these cases, the complexity and non-linearity of the physical, chemical, and meteorological processing is too large for the third order metamodel to give an accurate fit. Finally, sensitivity tests have been performed, to observe the response of the 16 metamodels (4 different meteorologies and 4 different urban types) to a broad set of potential inputs. These results were compared with observations of ozone, CO, formaldehyde, BC, and PM10 from a few well observed urban areas, and in most of the cases, the output distributions were found to be within ranges of the observations. Overall, a set of efficient and robust metamodels have been generated which are capable of simulating the effects of various physical, chemical, and meteorological processing, and capable of determining the urban concentrations, mole fractions, and fluxes of species, important to human health and the global climate.
Mercury deposition in Southern New Hampshire, 2006–2009
Authors: Lombard M. A. S. , Bryce J. G. , Mao H. , Talbot R.
Published: August 2011

Abstract. The atmospheric deposition of mercury (Hg) occurs via several mechanisms including wet, dry, and occult processes. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, event-based wet deposition samples and reactive gaseous Hg (RGM) measurements were collected for approximately 3 years at Thompson Farm (TF), a near-coastal rural site in Durham, NH, part of the University of New Hampshire AIRMAP Observing Network. Total aqueous mercury exhibited seasonal patterns in Hg wet deposition at TF. The lowest Hg wet deposition was measured in the winter with an average total seasonal deposition of 1.56 μg m−2 compared to the summer average of 4.71 μg m−2. Inter-annual differences in total wet deposition are generally linked with precipitation volume, with the greatest deposition occurring in the wettest year. Relationships between surface level RGM and Hg wet deposition were also investigated based on continuous RGM measurements at TF from November 2006 to September 2009. No correlations were observed between RGM mixing ratios and Hg wet deposition, however the ineffective scavenging of RGM during winter precipitation events was evidenced by the less frequent depletion of RGM below the detection level. Seasonal dry deposition of reactive gaseous Hg (RGM) was estimated using an order-of-magnitude approach. RGM mixing ratios and dry deposition estimates were greatest during the winter and spring. The seasonal ratios of Hg wet deposition to RGM dry deposition vary by up to a factor of 80.
Chemical and physical transformations of organic aerosol from the photo-oxidation of open biomass burning emissions in an environmental chamber
Authors: Hennigan C. J. , Miracolo M. A. , Engelhart G. J. , May A. A. , Presto A. A. , Lee T. , Sullivan A. P. , McMeeking G. R. , Coe H. , Wold C. E. , Hao W.-M. , Gilman J. B. , Kuster W. C. , de Gouw J. , Schichtel B. A. , Collett J. L. , Kreidenweis S. M. , Robinson A. L.
Published: August 2011

Abstract. Smog chamber experiments were conducted to investigate the chemical and physical transformations of organic aerosol (OA) during photo-oxidation of open biomass burning emissions. The experiments were carried out at the US Forest Service Fire Science Laboratory as part of the third Fire Lab at Missoula Experiment (FLAME III). We investigated emissions from 12 different fuels commonly burned in North American wildfires. The experiments feature atmospheric and plume aerosol and oxidant concentrations; aging times ranged from 3 to 4.5 h. OA production, expressed as a mass enhancement ratio (ratio of OA to primary OA (POA) mass), was highly variable. OA mass enhancement ratios ranged from 2.9 in experiments where secondary OA (SOA) production nearly tripled the POA concentration to 0.7 in experiments where photo-oxidation resulted in a 30 % loss of the OA mass. The campaign-average OA mass enhancement ratio was 1.7 ± 0.7 (mean ± 1σ); therefore, on average, there was substantial SOA production. In every experiment, the OA was chemically transformed. Even in experiments with net loss of OA mass, the OA became increasingly oxygenated and less volatile with aging, indicating that photo-oxidation transformed the POA emissions. Levoglucosan concentrations were also substantially reduced with photo-oxidation. The transformations of POA were extensive; using levoglucosan as a tracer for POA, unreacted POA only contributed 17 % of the campaign-average OA mass after 3.5 h of exposure to typical atmospheric hydroxyl radical (OH) levels. Heterogeneous reactions with OH could account for less than half of this transformation, implying that the coupled gas-particle partitioning and reaction of semi-volatile vapors is an important and potentially dominant mechanism for POA processing. Overall, the results illustrate that biomass burning emissions are subject to extensive chemical processing in the atmosphere, and the timescale for these transformations is rapid.
Absolute ozone absorption cross section in the Huggins Chappuis minimum (350–470 nm) at 296 K
Authors: Axson J. L. , Washenfelder R. A. , Kahan T. F. , Young C. J. , Vaida V. , Brown S. S.
Published: August 2011

Abstract. We report the ozone absolute absorption cross section between 350–470 nm, the minimum between the Huggins and Chappuis bands, where the ozone cross section is less than 10−22 cm2. Ozone spectra were acquired using an incoherent broadband cavity enhanced absorption spectrometer, with three channels centered at 365, 405, and 455 nm. The accuracy of the measured cross section is 2 %. Previous measurements vary by more than an order of magnitude in this spectral region. The measurements reported here provide much greater spectral coverage than the most recent measurements. We report a minimum absorption cross section of 3.4×10−24 cm2 at 381.8 nm, which is 22 % lower than the previously reported value. The effect of O3 concentration and water vapor partial pressure were investigated, however there were no observable changes in the absorption spectrum most likely due to the low optical density of the complex.
Modeling automotive FlexRay transceivers for signal integrity and EMC simulations
Authors: Günther H. , Hilger U. , Frei S.
Published: August 2011

Abstract. Automotive bus systems like FlexRay or CAN transmit safety critical data. To ensure correct functionality under all circumstances, extensive investigations about signal integrity and EMC have to be performed. To be able to use simulation in this validation process, suitable models for the components of the bus systems have to be developed. This paper shows how a combined transceiver model for signal integrity and EMC investigations can be created. The model shows good results in comparison to measurement data.
Inverse filtering for time, delay and integration X-ray imaging
Authors: Rosenbaum M. , Sauer-Greff W. , Urbansky R.
Published: August 2011

Abstract. In food industry, most finished products are scanned by X-ray for contaminations. These X-ray machines continuously scan the product passing through. To minimize the required X-ray power, a Time, Delay and Integration (TDI) CCD sensor is used to capture the image. While the product moves across the sensor area, the angle of the X-rays changes during the pass. This can be compensated for by adjusting the sensor shift speed to focus on a single plane of the product. If the product has a significant thickness, the image will show artifacts due to the laminographic effect. In this contribution we demonstrate that by the use of inverse filtering images which are focused on planes of different height can be generated out of a single X-ray image.
Fast beampattern evaluation by polynomial rooting
Authors: Häcker P. , Uhlich S. , Yang B.
Published: August 2011

Abstract. Current automotive radar systems measure the distance, the relative velocity and the direction of objects in their environment. This information enables the car to support the driver. The direction estimation capabilities of a sensor array depend on its beampattern. To find the array configuration leading to the best angle estimation by a global optimization algorithm, a huge amount of beampatterns have to be calculated to detect their maxima. In this paper, a novel algorithm is proposed to find all maxima of an array's beampattern fast and reliably, leading to accelerated array optimizations. The algorithm works for arrays having the sensors on a uniformly spaced grid. We use a general version of the gcd (greatest common divisor) function in order to write the problem as a polynomial. We differentiate and root the polynomial to get the extrema of the beampattern. In addition, we show a method to reduce the computational burden even more by decreasing the order of the polynomial.
A MIMO FMCW radar approach to HFSWR
Authors: Hinz J. O. , Zölzer U.
Published: August 2011

Abstract. In this paper we propose one possible approach how to apply the concept of multiple-input multiple-output (MIMO) to monostatic Frequency Modulated Continuous Wave (FMCW) High-Frequency Surface Wave Radar (HFSWR) in a maritime environment. Common tasks for a HFSWR are sea-state monitoring and ship detection, where our focus is on ship detection. A limiting factor in HFSWR is the available bandwidth, which is inversely proportional to the range resolution capability of the radar and typical below 100 kHz. The question is how to extend or combine a conventional single-input multiple-output (SIMO) FMCW phased-array type radar with stretch processing and the colocated MIMO concept to "reuse" the very limited HF radar band resources. Another important question to answer is how MIMO FMCW waveforms can be separated at the receiver.
Performance of combined constellation shaping and bit interleaved coded modulation with iterative decoding (BICM-ID)
Authors: Arafa T. , Sauer-Greff W. , Urbansky R.
Published: August 2011

Abstract. The increasing demand of achieving high data rates in modern communication systems requires highly efficient bandwidth utilization. For this purpose, multilevel modulation schemes are used in association with forward error correction (FEC) codes in order to approach the channel capacity. However, there is a gap between the capacity of a uniform signal constellation and the Shannon unconstrained capacity. This gap can be reduced by applying constellation shaping. The task of shaping is to modify a uniform distributed signal constellation towards a Gaussian like distribution. In this paper, we investigate different approaches to combine the constellation shaping with a bit interleaved coded modulation with iterative decoding (BICM-ID) system. Simulation results show that this combination can offer a shaping gain up to 0.6 dB.
An efficient architecture for the integration of sensor and actuator networks into the future internet
Authors: Schneider J. , Klein A. , Mannweiler C. , Schotten H. D.
Published: August 2011

Abstract. In the future, sensors will enable a large variety of new services in different domains. Important application areas are service adaptations in fixed and mobile environments, ambient assisted living, home automation, traffic management, as well as management of smart grids. All these applications will share a common property, the usage of networked sensors and actuators. To ensure an efficient deployment of such sensor-actuator networks, concepts and frameworks for managing and distributing sensor data as well as for triggering actuators need to be developed. In this paper, we present an architecture for integrating sensors and actuators into the future Internet. In our concept, all sensors and actuators are connected via gateways to the Internet, that will be used as comprehensive transport medium. Additionally, an entity is needed for registering all sensors and actuators, and managing sensor data requests. We decided to use a hierarchical structure, comparable to the Domain Name Service. This approach realizes a cost-efficient architecture disposing of "plug and play" capabilities and accounting for privacy issues.
Zuverlässigkeit digitaler Schaltungen unter Einfluss von intrinsischem Rauschen
Authors: Kleeberger V. B. , Schlichtmann U.
Published: August 2011

Abstract. Die kontinuierlich fortschreitende Miniaturisierung in integrierten Schaltungen führt zu einem Anstieg des intrinsischen Rauschens. Um den Einfluss von intrinsischem Rauschen auf die Zuverlässigkeit zukünftiger digitaler Schaltungen analysieren zu können, werden Methoden benötigt, die auf CAD-Verfahren wie Analogsimulation statt auf abschätzenden Berechnungen beruhen. Dieser Beitrag stellt eine neue Methode vor, die den Einfluss von intrinsischem Rauschen in digitalen Schaltungen für eine gegebene Prozesstechnologie analysieren kann. Die Amplituden von thermischen, 1/f und Schrotrauschen werden mit Hilfe eines SPICE Simulators bestimmt. Anschließend wird der Einfluss des Rauschens auf die Schaltungszuverlässigkeit durch Simulation analysiert. Zusätzlich zur Analyse werden Möglichkeiten aufgezeigt, wie die durch Rauschen hervorgerufenen Effekte im Schaltungsentwurf mit berücksichtigt werden können. Im Gegensatz zum Stand der Technik kann die vorgestellte Methode auf beliebige Logikimplementierungen und Prozesstechnologien angewendet werden. Zusätzlich wird gezeigt, dass bisherige Ansätze den Einfluss von Rauschen bis um das Vierfache überschätzen.
A low-noise high dynamic-range time-domain EMI measurement system for CISPR Band E
Authors: Hoffmann C. , Russer P.
Published: August 2011

Abstract. In this paper, a broadband time-domain EMI measurement system for measurements from 9 kHz to 18 GHz is presented that allows for compliant EMI measurements in CISPR Band E. Combining ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion, scan times can be reduced by several orders of magnitude in comparison to a traditional heterodyne EMI-receiver. The ultra-low system noise floor of 6–8 dB and the real-time spectrogram allow for the characterisation of the time-behaviour of EMI near the noise floor. EMI measurements of electronic consumer devices and electric household appliances are presented.
Accelerating the numerical computation of indirect lightning effects by means of vector fitting
Authors: Anatzki J. , Gronwald F.
Published: August 2011

Abstract. In the context of numerical computation of indirect lightning effects it is customary to use volume-discretizing methods in time domain, such as the Finite Difference Time Domain (FDTD) method, the Finite Integration Technique (FIT), or the Transmission Line Matrix (TLM) method. If standard lightning electromagnetic pulses (LEMPs) of tenths of microseconds duration are used as excitations, these methods require long computation times, as implied by the Courant criterion. It is proposed to use shorter pulse forms and to compare the transfer functions obtained by different pulse durations by means of macromodels that are obtained from the vector fitting method. Numerical computation of lightning related transfer functions of a canonical structure indicate that the duration of the exciting pulse can typically be shortened by at least one order of magnitude if compared to a standard pulse.
Multi beam observations of cosmic radio noise using a VHF radar with beam forming by a Butler matrix
Authors: Renkwitz T. , Singer W. , Latteck R. , Rapp M.
Published: August 2011

Abstract. The Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn started to install a new MST radar on the North-Norwegian island Andøya (69.30° N, 16.04° E) in 2009. The new Middle Atmosphere Alomar Radar System (MAARSY) replaces the previous ALWIN radar which has been successfully operated for more than 10 years. The MAARSY radar provides increased temporal and spatial resolution combined with a flexible sequential point-to-point steering of the radar beam. To increase the spatiotemporal resolution of the observations a 16-port Butler matrix has been built and implemented to the radar. In conjunction with 64 Yagi antennas of the former ALWIN antenna array the Butler matrix simultaneously provides 16 individual beams. The beam forming capability of the Butler matrix arrangement has been verified observing the galactic cosmic radio noise of the supernova remnant Cassiopeia A. Furthermore, this multi beam configuration has been used in passive experiments to estimate the cosmic noise absorption at 53.5 MHz during events of enhanced solar and geomagnetic activity as indicators for enhanced ionization at altitudes below 90 km. These observations are well correlated with simultaneous observations of corresponding beams of the co-located imaging riometer AIRIS (69.14° N, 16.02° E) at 38.2 MHz. In addition, enhanced cosmic noise absorption goes along with enhanced electron densities at altitudes below about 90 km as observed with the co-located Saura MF radar using differential absorption and differential phase measurements.
Classifying user states in next generation networks
Authors: He Y. , Bilgic A.
Published: August 2011

Abstract. In this paper we apply a classification method to learn geographic regions using Location Based Services (LBS) in IP Multimedia Subsystem (IMS). We assume that the information in Local Network (cellular network) can be freely exchanged with Global IP Network (IMS) and the information can be gathered in a data base. LBS in the IMS also provide location information for the data sets. Statistic classification methods are applied to the data sets in the data base. Depending on the information provided by the users, they are divided into different user groups (event classes) using Type Filters (TF). Then discriminant analysis is applied to the position information offered by LBS in IMS to determine the geographic regions of the different classes. The learned geographic regions can be used to inform the users in this region or other regions over IMS. This kind of service can be used for any location-based events.
Influences of weather phenomena on automotive laser radar systems
Authors: Rasshofer R. H. , Spies M. , Spies H.
Published: August 2011

Abstract. Laser radar (lidar) sensors provide outstanding angular resolution along with highly accurate range measurements and thus they were proposed as a part of a high performance perception system for advanced driver assistant functions. Based on optical signal transmission and reception, laser radar systems are influenced by weather phenomena. This work provides an overview on the different physical principles responsible for laser radar signal disturbance and theoretical investigations for estimation of their influence. Finally, the transmission models are applied for signal generation in a newly developed laser radar target simulator providing – to our knowledge – worldwide first HIL test capability for automotive laser radar systems.
Sensitivity analysis of waveguide eigenvalue problems
Authors: Burschäpers N. , Fiege S. , Schuhmann R. , Walther A.
Published: August 2011

Abstract. We analyze the sensitivity of dielectric waveguides with respect to design parameters such as permittivity values or simple geometric dependencies. Based on a discretization using the Finite Integration Technique the eigenvalue problem for the wave number is shown to be non-Hermitian with possibly complex solutions even in the lossless case. Nevertheless, the sensitivity can be obtained with negligible numerical effort. Numerical examples demonstrate the validity of the approach.
Verification of scattering parameter measurements in waveguides up to 325 GHz including highly-reflective devices
Authors: Schrader T. , Kuhlmann K. , Dickhoff R. , Dittmer J. , Hiebel M.
Published: August 2011

Abstract. Radio-frequency (RF) scattering parameters (S-parameters) play an important role to characterise RF signal transmission and reflection of active and passive devices such as transmission lines, components, and small-signal amplifiers. Vector network analysers (VNAs) are employed as instrumentation for such measurements. During the last years, the upper frequency limit of this instrumentation has been extended up to several hundreds of GHz for waveguide measurements. Calibration and verification procedures are obligatory prior to the VNA measurement to achieve accurate results and/or to obtain traceability to the International System of Units (SI). Usually, verification is performed by measuring well-matched devices with known S-parameters such as attenuators or short precision waveguide sections (shims). In waveguides, especially above 110 GHz, such devices may not exist and/or are not traceably calibrated. In some cases, e.g. filter networks, the devices under test (DUT) are partly highly reflective. This paper describes the dependency of the S-parameters a) on the calibration procedure, b) on the applied torque to the flange screws during the mating process of the single waveguide elements. It describes further c) how highly-reflective devices (HRD) can be used to verify a calibrated VNA, and d) how a measured attenuation at several hundreds of GHz can be substituted by a well-known coaxial attenuation at 279 MHz, the intermediate frequency (IF) of the VNA, to verify the linearity. This work is a contribution towards traceability and to obtain knowledge about the measurement uncertainty of VNA instrumentation in the millimetre-wave range.
Generation of postured voxel-based human models for the study of step voltage excited by lightning current
Authors: Gao J. , Munteanu I. , Müller W. F. O. , Weiland T.
Published: August 2011

Abstract. With the development of medical technique and computational electromagnetics, high resolution anatomic human models have already been widely developed and used in computation of electromagnetic fields induced in human body. Although these so called voxel-based human models are powerful tools for research on electromagnetic safety, their unchangeable standing posture makes it impossible to simulate a realistic scenario in which people have a lot of different postures. This paper describes a poser program package which was developed as an improved version of the free-from deformation technique to overcome this problem. It can set rotation angles of different human joints and then deform the original human model to make it have different postures. The original whole-body human model can be deformed smoothly, continuity of internal tissues and organs is maintained and the mass of different tissues and organs can be conserved in a reasonable level. As a typical application of the postured human models, this paper also studies the effect of the step voltage due to a lightning strike on the human body. Two voxel-based human body models with standing and walking posture were developed and integrated into simulation models to compute the current density distribution in the human body shocked by the step voltage. In order to speed up the transient simulation, the reduced c technique was used, leading to a speedup factor of around 20. The error introduced by the reduced c technique is discussed and simulation results are presented in detail.
Influence of short-term transfers on nitrogen fluxes, budgets and indirect N2O emissions in rural landscapes
Authors: Duretz S. , Drouet J.-L. , Durand P. , Cellier P.
Published: August 2011

Abstract. Spatial interactions at short-term may lead to large inputs of reactive nitrogen (Nr) to oligotrophic ecosystems and induce environmental threats such as additional N2O emissions and global warming. The paper presents a new methodology to estimate Nr fluxes, especially additional N2O emissions, at the landscape scale by taking into account spatial interactions between landscape elements. We used the NitroScape model which integrates processes of Nr transformation and short-term transfer in a dynamic and spatially distributed way to simulate Nr fluxes and budgets at the landscape scale. Four configurations of NitroScape were implemented by taking into account or not the atmospheric, hydrological or both pathways of Nr transfer. We simulated Nr fluxes, especially direct and indirect N2O emissions, within a test landscape including pig farms, croplands and unmanaged ecosystems. Simulation results showed the ability of NitroScape to simulate patterns of Nr losses and recapture for each landscape element and the whole landscape. They made it possible to quantify the contribution of both atmospheric and hydrological transfers in Nr fluxes and budgets. Indirect N2O emissions were estimated at almost 25 % of the total N2O emissions. They varied within the landscape according to land use, meteorological and soil conditions as well as topography. This first attempt has proved that the NitroScape model is a useful tool to estimate the effect of spatial interactions on Nr fluxes and budgets as well as indirect N2O emissions within landscapes. Our approach needs to be further tested by applying NitroScape to several spatial distributions of ecosystems within the landscape and to real and larger landscapes.
Use of the isotope flux ratio approach to investigate the C18O16O and 13CO2 exchange near the floor of a temperate deciduous forest
Authors: Santos E. , Wagner-Riddle C. , Lee X. , Warland J. , Brown S. , Staebler R. , Bartlett P. , Kim K.
Published: August 2011

Abstract. Stable isotopologues of CO2, such as 13CO2 and C18O16O, have been used to study the CO2 exchange between land and atmosphere. The advent of new measuring techniques has allowed near-continuous measurements of stable isotopes in the air. These measurements can be used with micrometeorological techniques, providing new tools to investigate the isotope exchange in ecosystems. The objectives of this study were to evaluate the use of the isotope flux ratio method (IFR) near the forest floor of a temperate deciduous forest and to study the temporal dynamics of δ18O of CO2 flux near the forest floor by comparing IFR estimates with estimates of δ18O of net soil CO2 flux provided by an analytical model. Mixing ratios of 12C16O2, 13CO2 and C16O18O were measured within and above a temperate deciduous forest, using the tunable diode laser spectroscopy technique. The half-hourly compositions of the CO2 flux near the forest floor (δ13CF and δ18OF) were compared with estimates provided by a modified Keeling plot technique (mKP) and by a Lagrangian dispersion analysis (WT analysis). The mKP and IFR δ18OF estimates showed good agreement (slope = 1.03 and correlation, R2 = 0.80). The δ13CF estimates from the two methods varied in a narrow range of −32.7 and −23.1 ‰; the mean (±SE) mKP and IFR δ13CF values were −27.5 ‰ (±0.2) and −27.3 ‰ (±0.1), respectively, and were statistically identical (p > 0.05). WT analysis and IFR δ18OF estimates showed better correlation (R2 = 0.37) when only turbulent periods (u* > 0.6 m s−1) were included in the analysis. The large data capture (~95 % of half-hour periods evaluated) for the IFR in comparison with mKP (27 %) shows that the former provides new opportunities for studying δ18O-CO2 flux dynamics within forest canopies. Values of δ18OF showed large temporal variation, with values ranging from −31.4 ‰ (DOY 208) to −11.2 ‰ (DOY 221). Precipitation events caused substantial variation (~8 ‰) in δ18OF over a period of approximately 24 h. A diel trend of δ18OF was observed, with more enriched values present during the daytime. Model simulations indicate that the activity of the carbon anhydrase enzyme was very variable during the evaluated period. These simulations indicate that more frequent sampling of δ18O of soil water could improve the estimates of δ18O of net soil CO2 flux.
The Southern Annular Mode: a comparison of indices
Authors: Ho M. , Kiem A. S. , Verdon-Kidd D. C.
Published: August 2011

Abstract. The Southern Annular Mode (SAM) has been identified as a climate mechanism with potentially significant impacts on the Australian hydroclimate. However, despite the identification of some relationships between SAM and Australia's hydroclimate, the association has not been extensively explored or robustly quantified. Further complicating the situation is the existence of numerous indices (or methods) by which SAM has been approximated. In this paper, the various SAM definitions and indices are reviewed and the similarities and discrepancies are discussed, along with the strengths and weaknesses of each index development approach. Further, the sensitivity of the relationship between SAM and Australian rainfall on choice of SAM index is quantified and recommendations are given as to the most appropriate index to use when assessing the impacts of the SAM on Australia's hydroclimate.
CA 15–3 Serum Levels in Patients with Ductal Breast Carcinoma: Relationship with Clinicopathological Parameters and Tumor Markers
Authors: González-Sistal Angel , Arias José Ignacio , Ruibal Álvaro
Published: August 2011

Introduction

Cancer antigen 15–3 (CA 15–3) is the most widely used serum marker in diagnosing and monitoring breast cancer. The aim of this work was to analyze preoperative CA 15–3 serum levels in patients with ductal breast carcinoma in relation to 1) clinicopathological parameters, 2) hormone receptors, and 3) tissue-based tumor markers.

Methods

A group of 340 women with infiltrating ductal carcinoma of the breast who had undergone no prior treatment was studied. These women ranged in age between 27 and 83 years (mean age 61.5±9.9 years). Preoperative CA 15–3 serum levels were determined by an immunoradiometric method. Hormone receptors (estrogen, progesterone and androgen receptors), p53, bcl-2 and Ki67 were determined by different immunohistochemical methods. Epidermal growth factor receptor (EGFR) was analyzed in the cell membranes by radioligand assay whereas cathepsin D and pS2 were determined by immunoradiometric analysis. Tumor ploidy and S-phase fraction were studied by flow cytometry.

Results

CA 15–3 serum levels were higher in postmenopausal women (p=0.032), in patients with tumors exceeding 2 cm (p=0.003), lymph node involvement (p=0.026), distant metastases (M1) (p<0.0001), S-phase fraction <7% (p=0.015), EGFR <6 fmol/mg protein (p=0.025), and cathepsin D <50 pmol/mg protein (p=0.023).

Conclusions

Preoperative CA 15–3 serum levels were associated with cell proliferation determined by the S-phase fraction, the concentration of cathepsin D in the cytosol, and the EGFR concentration in the cell membrane.
Assimilation of Tourism Satellite Accounts and Applied General Equilibrium Models to Inform Tourism Policy Analysis
Authors: Rossouw Riaan , Saayman Melville
Published: August 2011

Historically, tourism policy analysis in South Africa has posed challenges to accurate measurement. The primary reason for this is that tourism is not designated as an ‘industry’ in standard economic accounts. This paper therefore demonstrates the relevance and need for applied general equilibrium (AGE) models to be completed and extended through an integration with tourism satellite accounts (TSAs) as a tool for policy makers (especially tourism policy makers) in South Africa. The paper sets out the reasons behind the need for economic models for policy analysis and other purposes, and gives an overview of old and new approaches to tourism policy modelling. The relevance of integrated models to, specifically, tourism policy analysis both internationally and in the South African context is discussed, followed by an illustrative empirical simulation of an exogenous inbound tourism expansion of 10%, against the background of the relationship between tourism and economic development. Furthermore, the indirect effects of an input–output model are also presented for comparison. The results confirm that the integrated approach is a more accurate tool for policy analysis.
Factors Affecting the Travel Expenditure of Visitors to Macau, China
Authors: Kim Woo Gon , Kim Taegoo (Terry) , Gazzoli Gabriel , Park Yumi , Kim Sang Hyuck , Park Si Sa
Published: August 2011

This study examines factors affecting the travel expenditures of visitors to Macau. Employing Tobit analysis, the study investigates the effects of socio-demographic and trip-related characteristics on total expenditure, as well as various travel expenditures across different expenditure functions. Three locations were used for data collection: the border gate with mainland China, the Macau ferry terminal and Macau International Airport. Tourists who were married, had a higher education background and household income and were in a large party tended to spend more on total travel-related expenditures. Distance to Macau turned out to be another important variable affecting tourists' travel expenditure patterns. Compared to tourists from mainland China or Hong Kong, long-haul foreign tourists to Macau spent more on lodging and shopping. Considering the high contribution margin of international long-haul tourists, Macau's tourism industry should entice more of these visitors to generate even higher revenues.
Research Note: Long-Lasting Effects and Welfare Costs of Fluctuations
Authors: Ping Lei
Published: August 2011

The tourism industry is growing rapidly but is also highly fluctuating. Using China's inbound tourism market as the object and based on the B–N data decomposition theory, this paper adopts the statistics of variance ratio to measure the long-lasting effects of stochastic fluctuations on China's inbound tourism industry. It also discusses the influences of stochastic fluctuations and the decreasing growth rate on the welfare of China's inbound tourism. The conclusion is that undoubtedly China's inbound tourism industry will continue to grow, but the impact of stochastic shocks will endure for a relatively long time. Twenty-four per cent of the long-term fluctuation of China's inbound tourism industry is the result of stochastic shocks, whose effect, in the short term, will continue to be reinforced. Though the elimination of fluctuations will increase welfare by 0.40%, lowering the growth rate will decrease welfare by a larger percentage. If the monthly growth rate decreases by 0.1%, welfare will fall by about 19.37%, 48 times the amount of welfare loss without fluctuation. Therefore, China's inbound tourism business should stick to the long-term policy of facilitating growth, while some administrative and legislative measures should be taken to address the negative impact of stochastic fluctuation appropriately.
Judgemental Forecasting Support Systems in Tourism
Authors: Croce Valeria , Wöber Karl W.
Published: August 2011

In an increasingly competitive industry, tourism managers are faced with the necessity of estimating future values of demand in the short term despite the limitations of scarcity, volatility and uncertainty. A convenient and flexible approach such as judgemental forecasting holds promise in addressing the major issues in the field of tourism demand forecasting. This paper presents an innovative approach, which uses the opportunities offered by decision support systems to tackle the main issues associated with judgemental forecasting. A forecasting system that supports collaborative short-term forecasting tasks among tourism managers is offered as a case example.