Showing papers by "Fraunhofer Society published in 1997"
05 Nov 1997
TL;DR: In this paper, a unified framework for object oriented cohesion measures is presented, which is based on the issues discovered in a review of object-oriented cohesion measures, and contributes to an increased understanding of the state of the art as it is a mechanism for comparing measures and their potential use.
Abstract: The increasing importance being placed on software measurement has led to an increased amount of research in developing new software measures. Given the importance of object oriented development techniques, one specific area where this has occurred is cohesion measurement in object oriented systems. However despite an interesting body of work, there is little understanding of the motivations and empirical hypotheses behind many of these new measures. It is often difficult to determine how such measures relate to one another and for which application they can be used. As a consequence, it is very difficult for practitioners and researchers to obtain a clear picture of the state of the art in order to select or define cohesion measures for object oriented systems. To help remedy this situation a unified framework, based on the issues discovered in a review of object oriented cohesion measures, is presented. The unified framework contributes to an increased understanding of the state of the art as it is a mechanism for: (i) comparing measures and their potential use, (ii) integrating existing measures which examine the same concepts in different ways, and (iii) facilitating more rigorous decision making regarding the definition of new measures and the selection of existing measures for a specific goal of measurement.
490 citations
TL;DR: A powder metallurgical method which allows the production of aluminium foams with porosity levels up to 90% is described in this article, which typically have closed pores and densities ranging from 0.4 to 1 g cm−3.
297 citations
TL;DR: In this article, the authors used a fully automated measuring system to determine the annual cycles of NO, NO2 and N2O emission rates from soil at a spruce (control and limed plot) and beech forest site (Hoglwald) in Southern Germany (Bavaria).
Abstract: Annual cycles of NO, NO2 and N2O emission rates from soil were determined with high temporal resolution at a spruce (control and limed plot) and beech forest site (“Hoglwald”) in Southern Germany (Bavaria) by use of fully automated measuring systems. The fully automated measuring system used for the determination of NO and NO2 flux rates is described in detail. In addition, NO, NO2 and N2O emission rates from soils of different pine forest ecosystems of Northeastern Germany (Brandenburg) were determined during 2 measuring campaigns in 1995. Mean monthly NO and N2O emission rates (July 1994–June 1995) of the untreated spruce plot at the Hoglwald site were in the range of 20–130 µg NO-N m-2 h-1 and 3.5–16.4 µg N2O-N m-2 h-1, respectively. Generally, NO emission exceeded N2O emission. Liming of a spruce plot resulted in a reduction of NO emission rates (monthly means: 15–140 µg NO-N m-2 h-1) by 25-30% as compared to the control spruce plot. On the other hand, liming of a spruce plot significantly enhanced over the entire observation period N2O emission rates (monthly means: 6.2–22.1 µg N2O-N m-2 h-1). Contrary to the spruce stand, mean monthly N2O emission rates from soil of the beech plot (range: 7.9–102 µg N2O-N m-2 h-1) were generally significantly higher than NO emission rates (range: 6.1–47.0 µg NO-N m-2 h-1). Results obtained from measuring campaigns in three different pine forest ecosystems revealed mean N2O emission rates between 6.0 and 53.0 µg N2O-N m-2 h-1 and mean NO emission rates between 2.6 and 31.1 µg NO-N m-2 h-1. The NO and N2O flux rates reported here for the different measuring sites are high compared to other reported fluxes from temperate forests. Ratios of NO/N2O emission rates were >> 1 for the spruce control and limed plot of the Hoglwald site and << 1 for the beech plot. The pine forest ecosystems showed ratios of NO/N2O emission rates of 0.9 ± 0.4. These results indicate a strong differentiating impact of tree species on the ratio of NO to N2O emitted from soil.
231 citations
TL;DR: In this article, two rice (Oryza sativa var. japonica) cultivars, Lido and Roma, were tested in the field for methane production, oxidation and emission.
Abstract: Two Italian rice (Oryza sativa var. japonica) cultivars, Lido and Roma, were tested in the field for methane production, oxidation and emission. In two consecutive years, fields planted with the rice cultivar Lido showed methane emissions 24-31% lower than fields planted with the cultivar Roma. This difference was observed irrespective of fertilizer treatment. In contrast to methane emissions, differences in methane production or oxidation were not observed between fields planted with the two cultivars. Plant-mediated transport of methane from the sediment to the atmosphere was the dominating pathway of methane emission. During the entire vegetation period, the contribution of this pathway to total methane emission amounted to c. 90%, whereas the contribution of gas bubble release and of diffusion through the water column to total methane emission was of minor significance. Results obtained from transport studies of tracer gas through the aerenchyma system of rice plants demonstrated that the root-shoot transition zone is the main site of resistance to plant-mediated gas exchange between the soil and the atmosphere. The cultivar Lido, showing relatively low methane emissions in the field, had a significantly lower gas transport capacity through the aerenchyma system than the cultivar Roma. Thus, the observed differences in methane emissions in the field between the cultivars Lido and Roma can be explained by different gas transport capacities. Apparently, these differences in gas transport capacities are a consequence of differences in morphology of the aerenchyma systems, especially in the root-shoot transition zone. It is, therefore, concluded that identification and use of high-yielding rice cultivars which have a low gas transport capacity represent an economically feasible, environmentally sound and promising approach to mitigating methane emissons from rice paddy fields.
222 citations
TL;DR: Investigations of highly efficient grating couplers for polymer slab and strip waveguides fabricated by electron-beam lithography are reported and a focusing blazed grating that couples the light with an efficiency of 42% into a polymer strip waveguide is reported.
Abstract: Investigations of highly efficient grating couplers for polymer slab and strip waveguides fabricated by electron-beam lithography are reported A maximum input efficiency of 67% is achieved The electron-beam direct-writing technique allows one to replicate the original gratings into polymer substrates by embossing An all-polymeric optical chip with efficient grating couplers is demonstrated Waveguide grating couplers with blazed profile and variable grating depth are investigated Thus, the intensity distribution of the outcoupled light is matched to a Gaussian-like profile A focusing blazed grating that couples the light with an efficiency of 42% into a polymer strip waveguide is reported A curvature correction of the grating lines allows one to improve the focusing properties
169 citations
03 Mar 1997
TL;DR: This work presents a method for the reconstruction of real-world objects from multiple range images based on a least-squares approach where a distance metric between the overlapping range images is minimized and a resolution hierarchy accelerates the registration substantially.
Abstract: Presents a method for the reconstruction of real-world objects from multiple range images. One major contribution of our approach is the simultaneous registration of all range images acquired from different scanner views. Thus, registration errors are not accumulated, and it is even possible to reconstruct large objects from an arbitrary number of small range images. The registration process is based on a least-squares approach where a distance metric between the overlapping range images is minimized. A resolution hierarchy accelerates the registration substantially. After registration, a volumetric model of the object is carved out. This step is based on the idea that no part of the object can lie between the measured surface and the camera of the scanner. With the marching cube algorithm, a polygonal representation is generated. The accuracy of this polygonal mesh is improved by moving the vertices of the mesh on to the surface implicitly defined by the registered range images.
154 citations
TL;DR: The most promising approach is the parallel observation of patents and publications in order to analyse the dynamics of the interaction of science and technology and the professional move of academic and industrial researchers between institutions.
Abstract: The relationship between science and technology is an important issue, as science-based technologies play a key role in modern economies. The exploration of the science-technology interface can be effectively supported by quantitative indicators, in particular patents of scientific institutions, publications of industrial enterprises, and scientific references in patent search reports. The most promising approach is the parallel observation of patents and publications in order to analyse the dynamics of the interaction of science and technology and the professional move of academic and industrial researchers between institutions.
147 citations
01 Jan 1997
TL;DR: Simulation results which indicate the capabilities of the methodology for electro-thermal simulation are compared to experimental results and a time step algorithm is used.
Abstract: The paper presents a methodology for simulating the static and dynamic performance of integrated circuits in the presence of electro-thermal interactions on the integrated circuit die. The technique is based on the coupling of a finite element method (FEM) program with a circuit simulator. In difference to other known simulator couplings a time step algorithm is used. Its implementation into simulation tools is described. The thermal modeling of the die/package structure and the extended modeling of the electronic circuit is discussed. Simulation results which indicate the capabilities of the methodology for electro-thermal simulation are compared to experimental results.
137 citations
TL;DR: In this article, a new generation of flexible and extremely light-weight electrode arrays with integrated cables was developed, which overcomes the "classical" separation of substrate and insulation layers.
Abstract: It has been shown previously that peripheral nerve axons regenerate through microvias in silicon devices. A major challenge in the design of a biocompatible interface is to establish a reliable electrical and mechanical interconnection to signal-processing and transmission electronics which allows simultaneous multichannel recordings or stimulation of nerves. This paper describes the on-going work of developing a new generation of flexible and extremely light-weight electrode arrays with integrated cables. A process technology has been established to fabricate a multilayer device with micromachining methods, which overcomes the ‘classical’ separation of substrate and insulation layers. The micromachined electrodes exhibit promising mechanical stability and high insulation resistance.
130 citations
TL;DR: This review summarizes major functional and phenotypical features of neutrophils induced by G-CSF treatment in patients with acquired and congenital neutropenias and focuses on the differential effect of G- CSF and GM-SF on neutrophil function in vitro and in vivo.
Abstract: G-CSF and GM-CSF are hematopoietic growth factors required for proliferation and differentiation of hematopoietic precursors. G-CSF is now widely used to overcome neutropenias of various origins. Beside the absolute number, the functional capacity of neutrophils at sites of inflammation is of major importance in host defense. This review summarizes major functional and phenotypical features of neutrophils induced by G-CSF treatment in patients with acquired and congenital neutropenias. Furthermore, we focus on the differential effect of G-CSF and GM-CSF on neutrophil function in vitro and in vivo. Some of the altered abilities of cytokine-induced neutrophils are important to understand side-effects of G-CSF therapy.
123 citations
TL;DR: In this article, a set of 17 model parametrizations are developed, including simple criteria for deciding which parameter is to be used in modelling a robot, and the model continuity within each parameter's application range is shown by means of differential geometry.
Abstract: New general kinematic models for robot calibration are presented in this paper These models have the distinct advantage of satisfying the model-parameter identification requirements of completeness, minimality and model continuity for all combinations and configurations of revolute and prismatic joints A set of 17 model parametrizations are developed, including simple criteria for deciding which parametrizations are to be used in modelling a robot The parametrizations presented also result in an accurate representation of the physical robot and thus allow realistic integration of elastic deformation models Model continuity within each parametrization's application range is shown by means of differential geometry Also shown is how these models are be extracted from a non-complex “vector-chain” description of a robot
TL;DR: In this article, the authors present the results of the energy indicator analysis of European manufacturing industries carried out in a recent European project and establish the general scope and limitations of the method when applied practically, especially in negotiation processes.
TL;DR: In this paper, the authors describe the fabrication and characterisation of a thick-film humidity sensor based on the semiconducting metal oxide MnWO 4, which possesses a novel "sandwich"-configuration with a 40 μm porous MnwO 4 ceramic layer sandwiched by two 10 μm polarity-reversed, interdigitated metal films.
Abstract: The paper describes the results of studies on the fabrication and characterisation of a thick-film humidity sensor based on the semiconducting metal oxide MnWO 4 . The sensor element possesses a novel ‘sandwich’-configuration with a 40 μm porous MnWO 4 ceramic layer sandwiched by two 10 μm polarity-reversed, interdigitated metal films. Instead of traditional glass frits, LiCl powders are used as adhesion promoters for sintering the sensor paste. With this method, MnWO 4 powders with an average particle size of 3.0 μm are sintered at the standard thick-film firing temperature of 850°C. The sintered ceramic layer exhibits a porous structure. The novel electrode arrangement combines the advantages of humidity sensors in the form of a parallel capacitor with those in the form of an interdigital capacitor, permitting a high sensitivity and a fast response. The influence of temperature on the sensor characteristics has been compensated for by integrating a thick-film NTC resistor. The humidity sensor shows no cross-sensitivity to organic vapour. The organic contamination on the sensor surface can be burned out by heating the sensor element at about 400°C with the refresh heater printed on the back side of the substrate.
TL;DR: In this paper, the Guenther emission algorithm was used to predict the daily maximum of the isoprene emission within the plant specific uncertainty range, however, the morning increase and the afternoon drop in the ISOPrene emission is not well parameterized.
24 Oct 1997
TL;DR: This paper investigates the basic tenets of meta-modeling in the context of distributed object environments, and defines the basic properties required of a suitable meta- modeling framework by examining the nature of the meta-models proposed for such environments.
Abstract: Meta-modeling is critical to the success of distributed object environments such as CORBA and ActiveXI DCOM. However, there is a surprisingly large variation in the nature of the meta-models (and meta-meta-models) that have been proposed for such environments. This paper investigates this phenomenon by examining the basic tenets of meta-modeling in the context of distributed object environments, and by defining the basic properties required of a suitable meta-modeling framework. The paper is not concerned with the content of the meta-models, per se, but rather with the form that this content should take, and the rules that it should adhere to. The ramifications of these rules on the notations and languages for distributed object environments are then considered.
TL;DR: The person authentication system SESAM is described, which combines three different biometric cues to reach robust identification and verification, and a field test is done to show that this approach leads to a reliable people authentication system.
TL;DR: In this article, surface ozone data from 25 Europeanlow-altitude sites and mountain sites located between 79°N and 28°N were studied for the time period March 1989-February 1993.
Abstract: Surface ozone data from 25 Europeanlow-altitude sites and mountain sites located between79°N and 28°N were studied. The analysiscovered the time period March 1989–February 1993.Average summer and winter O3 concentrations inthe boundary layer over the continent gave rise togradients that were strongest in the north-west tosouth-east direction and west-east direction, respectively. WintertimeO3 ranged from 19 to 27 ppbover the continent, compared to about 32 ppb at thewestern border, while for summer the continentalO3 values ranged between 39 and 56 ppb and theoceanic mixing ratios were around 37 ppb. In the lowerfree troposphere average wintertime O3 mixingratios were around 38 ppb, with only an 8 ppbdifference between 28°N and 79°N. For summerthe average O3 levels decreased from about 55 ppbover Central Europe to 32 ppb at 79°N. Inaddition, O3 and Ox(= O3 + NO2)in polluted and clean air were compared. Theamplitudes of the seasonal ozone variations increasedin the north-west to south-east direction, while thetime of the annual maximum was shifted from spring (atthe northerly sites) to late summer (at sites inAustria and Hungary), which reflected the contributionof photochemical ozone production in the lower partsof the troposphere.
TL;DR: In this paper, a simple small-signal equivalent circuit for the heterojunction bipolar transistor (HBT) is proposed, which uses a direct extraction method to determine the parasitic elements, in particular the parasitic capacitances.
Abstract: A physical, yet simple, small-signal equivalent circuit for the heterojunction bipolar transistor (HBT) is proposed. This circuit was established by analyzing in detail the physical operation of the HBT. The model verification was carried out by comparison of the measured and simulated S- and Z-parameters for both passive (reverse-biased) and active bias conditions. A feature of this model is that it uses a direct extraction method to determine the parasitic elements, in particular, the parasitic capacitances. The excellent agreement between the measured and simulated parameters was verified all over the frequency range from 0.25 to 75 GHz.
TL;DR: In this paper, the authors present a physical interpretation of the reported wavelength dependence of this particular cloud, which shows that the transmission of the cloud alone does not vary significantly with wavelength in the UV, but due to radiation scattered upwards from the cloud and then scattered downwards again, effectively trying to make it through the cloud more than once.
Abstract: In the recently published GRL paper by Seckmeyer et al. [1996] an example of a cloud that has a wavelength dependent effect on the surface UV-radiation is given. Through careful and accurate radiative transfer modelling, the present paper aims to give a physical interpretation of the reported wavelength dependence of this particular cloud. The modelling shows that the transmission of the cloud alone does not vary significantly with wavelength in the UV. However, the cloud gives a wavelength dependent effect in the surface UV-radiation due to radiation scattered upwards from the cloud and then scattered downwards again, effectively trying to make it through the cloud more than once. The number of photons this happens to is a function of the wavelength dependent Rayleigh scattering and ozone absorption cross sections.
TL;DR: The independent replication of a controlled experiment which compared three defect detection techniques for software requirements inspections, and evaluated the benefits of collection meetings after individual reviews confirmed one result of the original experiment: the defect detection rate is not improved by collection meetings.
Abstract: This paper presents the independent replication of a controlled experiment which compared three defect detection techniques (Ad Hoc, Checklist, and Defect-based Scenario) for software requirements inspections, and evaluated the benefits of collection meetings after individual reviews. The results of our replication were partially different from those of the original experiment. Unlike the original experiment, we did not find any empirical evidence of better performance when using scenarios. To explain these negative findings we provide a list of hypotheses. On the other hand, the replication confirmed one result of the original experiment: the defect detection rate is not improved by collection meetings.
The independent replication was made possible by the existence of an experimental kit provided by the original investigators. We discuss what difficulties we encountered in applying the package to our environment, as a result of different cultures and skills. Using our results, experience and suggestions, other researchers will be able to improve the original experimental design before attempting further replications.
TL;DR: In this article, an external wall system for solar space heating and daylighting composed of transparent insulation material (TIM) and translucent phase change material (PCM) is presented.
TL;DR: In this article, the authors realized a three dimensional metallization for vertically integrated circuits (VIC) using a newly developed technology that allows stacking and vertical interchip wiring of completely processed and electrically tested wafers using available microelectronic processes.
TL;DR: In this paper, a silicon-on-insulator (SOI) RF complementary metal-oxide-semiconductor (CMOS) technology for microwave applications up to 5 GHz has been developed.
Abstract: A silicon-on-insulator (SOI) RF complementary metal-oxide-semiconductor (CMOS) technology for microwave applications up to 5 GHz has been developed. The technology is based on ultra large scale integration (ULSI) CMOS processing using a high resistivity separation through implanted oxygen (SIMOX) substrate of typically 10 k/spl Omega/cm. Dedicated RF n-channel and RF p-channel MOSFET's with an effective channel length of 0.20 and 0.40 /spl mu/m have been fabricated using a multiple gate finger design. Maximum frequencies of operation f/sub max/ of 46 GHz (NMOS) and 16 GHz (PMOS) have been measured. Metal-Insulator-Metal (MIM) capacitances with up to 63 pF with 70 nF/cm/sup 2/, planar inductances with up to 25 nH and a quality factor up to 12 and coplanar waveguides with a loss <2.8 dB/cm at 5 GHz are monolithically integrated in the technology without additional processes and materials. Using this SOI-CMOS technology we have fabricated integrated silicon RF circuits, e.g., amplifiers, oscillators, and mixers, operating in the 2 GHz range.
TL;DR: It is suggested that the use of nanofiltration membranes for the recovery of phosphorous with a second type of technology is a viable process and should be considered as a possibility for further research.
TL;DR: In this paper, an optical flow-measurement technique has been developed to enhance the measurement range into the desired low flow range (10 -3 to 1 μl min -1 ).
Abstract: To investigate the performance of microengineered fluid channels in liquid dosing applications, flow-rate measurements have been performed with various channel geometries in a range from 0.01 to 1000 μl min -1 . An optical flow-measurement technique has been developed to enhance the measurement range into the desired low flow range (10 -3 to 1 μl min -1 ), and is compared to a standard gravimetric method, which is preferably used for flow rates above 1 μl min -1 . In addition, influences of the temperture-dependent viscosity and effects arising from fluidmechanical characteristics are studied. These influences are also calculated from laminar flow theory and semi-emprical models to obtain a theoretical model. It is found that the theoretical model is able to describe the measurement results well in the whole flow range. The model is implemented on a PC-based system, which measures the pressure drop across the microchannel and the fluid temperature and calculates the flow. In a temperature range from 20 to 50°C excellent agreement is found.
TL;DR: In this article, a linear correlation between performance ratio and the yearly average daytime temperature at a site is observed, and the variation of the module performance ratio with yearly or monthly irradiation sums and average temperatures is given.
TL;DR: The optimization of the impedance behavior of implantable electrode arrays with via holes allows for simultaneous nerve stimulation and signal recording and may eventually lead to devices driving sensory motor prosthesis with closed loop control.
TL;DR: Results strongly suggest that quality guidelines based on Coad and Yourdon principles have a beneficial effect on the maintainability of object-oriented design documents, however, there is no strong evidence regarding the alleged higher maintainabilityof object- oriented design documents over structured design documents.
Abstract: Several important questions still need to be answered regarding the maintainability of object-oriented design documents. This paper focuses on the following issues: are object-oriented design documents easier to understand and modify than structured design documents? Do they need to comply with quality guidelines such as the ones provided by Coad and Yourdon? What is the impact of such quality standards on the understandability and modifiability of design documents? Answers can be based on informed opinion or empirical evidence. Since software technology investments are substantial and contradictory opinions exist regarding design strategies, performing empirical studies on these topics is a relevant research activity.
This paper presents a controlled experiment performed with computer science students as subjects. Results strongly suggest that quality guidelines based on Coad and Yourdon principles have a beneficial effect on the maintainability of object-oriented design documents. However, there is no strong evidence regarding the alleged higher maintainability of object-oriented design documents over structured design documents. Furthermore, results suggest that object-oriented design documents are more sensitive to poor design practices, in part because their cognitive complexity becomes increasingly unmanageable. However, because our ability to generalise these results is limited, they should be considered as preliminary, i.e., it is very likely that they can only be generalised to programmers with little object-oriented training and programming experience. Such programmers can, however, be commonly found on maintenance projects. As well as additional research, external replications of this study are required to confirm the results and achieve confidence in these findings.
TL;DR: In this paper, a methodology for simulating the static and dynamic performance of integrated circuits in the presence of electro-thermal interactions on the integrated circuit die is presented, which is based on the coupling of a finite element method (FEM) program with a circuit simulator.
Abstract: The paper presents a methodology for simulating the static and dynamic performance of integrated circuits in the presence of electro-thermal interactions on the integrated circuit die. The technique is based on the coupling of a finite element method (FEM) program with a circuit simulator. In contrast to other known simulator couplings a time step algorithm is used, Its implementation in simulation tools is described. The thermal modeling of the die/package structure and the extended modeling of the electronic circuit is discussed. Simulation results which indicate the capabilities of the methodology for electro-thermal simulation are compared to experimental results.
16 Jun 1997
TL;DR: In this paper, an approach to extract quantitative geometric descriptions of the movements of persons by fitting the projection of a 3D human model to consecutive frames of an image sequence is presented.
Abstract: We present an approach to extract quantitative geometric descriptions of the movements of persons by fitting the projection of a 3-dimensional human model to consecutive frames of an image sequence. The kinematics of the human model is given by a homogeneous transformation tree and its body parts are modeled by right-elliptical cones. The proposed approach can determine the values of a varying number of degrees of freedom (DOFs; body joints, position and orientation of the person relative to the camera) according to the application and the kind of image sequence. The determination of the DOFs is understood as an estimation problem which is solved by an iterated extended Kalman filter (IEKF). For this purpose, the human model is augmented by a simple motion model of constant velocity for all DOFs which is used in the prediction step of the IEKF. In the update step both region and edge information is used.