Showing papers by "Fraunhofer Society published in 2000"

Engineering support vector machine kernels that recognize translation initiation sites

Abstract: Motivation: In order to extract protein sequences from nucleotide sequences, it is an important step to recognize points at which regions start that code for proteins. These points are called translation initiation sites (TIS). Results: The task of finding TIS can be modeled as a classification problem. We demonstrate the applicability of support vector machines for this task, and show how to incorporate prior biological knowledge by engineering an appropriate kernel function. With the described techniques the recognition performance can be improved by 26% over leading existing approaches. We provide evidence that existing related methods (e.g.ESTScan) could profit from advanced TIS recognition. Contact: {Alexander.Zien,Gunnar.Raetsch,Sebastian.

Micromachined, Polyimide-Based Devices for Flexible Neural Interfaces

Abstract: Micromachining technologies were established to fabricate microelectrode arrays and devices for interfacing parts of the central or peripheral nervous system in case of neuronal disorders. The devices were part of a neural prosthesis that allows simultaneous multichannel recording and multisite stimulation of neurons. Overcoming the brittle mechanics of silicon, we established a process technology to fabricate light-weighted and highly flexible polyimide based devices. Concerning the challenging housing demands close to the nerve to prevent mechanical induced nerve traumatization, we integrated interconnects to decouple the nerve interface from plugs and signal processing electronics. Hybrid integration with a new assembling technique—the MicroFlex interconnection (MFI)—has been applied for the connection of the flexible microsystems to silicon microelectronics. In this paper, we present different shapes and applications of the flexible electrodes: sieve electrodes for regeneration studies, cuff electrodes for interfacing peripheral nerves, and a retina implant for ganglion cell stimulation. The discussion is focused on electrode and material properties and the hybrid assembly of a fully implantable neural prosthesis.

A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics

Abstract: In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.

Industrialization of Powder Compact Toaming Process

Abstract: The potential for applying metal foams in lightweight construction is mainly based on the increased stiffness of two flat or curved sheets that are separated by a foam layer as compared to a single sheet of the same weight. By using sandwiches with an aluminum-foam core, it is possible to obtain a higher stiffness and rigidity, maintaining stability against buckling and additionally making use of the high energy dissipation capability of the foams. A recent highlight in lightweight construction is the use of aluminum-foam sandwiches (AFSs) in space-frame constructions.

A replicated assessment and comparison of common software cost modeling techniques

Abstract: Delivering a software product on time, within budget, and to an agreed level of quality is a critical concern for many software organizations. Underestimating software costs can have detrimental effects on the quality of the delivered software and thus on a company's business reputation and competitiveness. On the other hand, overestimation of software cost can result in missed opportunities to funds in other projects. In response to industry demand, a myriad of estimation techniques has been proposed during the last three decades. In order to assess the suitability of a technique from a diverse selection, its performance and relative merits must be compared. The current study replicates a comprehensive comparison of common estimation techniques within different organizational contexts, using data from the European Space Agency. Our study is motivated by the challenge to assess the feasibility of using multi-organization data to build cost models and the benefits gained from company-specific data collection. Using the European Space Agency data set, we investigated a yet unexplored application domain, including military and space projects. The results showed that traditional techniques, namely, ordinary least-squares regression and analysis of variance outperformed analogy-based estimation and regression trees. Consistent with the results of the replicated study no significant difference was found in accuracy between estimates derived from company-specific data and estimates derived from multi-organizational data.

Characterization of methane emissions from rice fields in Asia. III. Mitigation options and future research needs

Abstract: Methane (CH4) emissions from rice fields were determined using automated measurement systems in China, India, Indonesia, Thailand, and the Philippines Mitigation options were assessed separately for different baseline practices of irrigated rice, rainfed, and deepwater rice irrigated rice is the largest source of CH4 and also offers the most options to modify crop management for reducing these emissions Optimizing irrigation patterns by additional drainage periods in the field or an early timing of midseason drainage accounted for 70%–80% of CH4 emissions of the respective baseline practice In baseline practices with high organic amendments, use of compost (5863%), biogas residues (10–16%), and direct wet seeding (16–22%) should be considered mitigation options In baseline practices using prilled urea as sole N source, use of ammonium sulfate could reduce CH4 emission by 1067% In all rice ecosystems, CH4 emissions can he reduced by fallow incorporation (11%) and mulching (11%) of rice straw as well as addition of phosphogypsum (9–73%) However, in rainfed and deepwater rice, mitigation options are very limited in both number and potential gains The assessment of these crop management options includes their total factor productivity and possible adverse effects Due to higher nitrous oxide (N,O) emissions, changes in water regime are only recommended for rice systems with high baseline emissions of CH4 Key objectives of future research are identifying and characterizing high-emitting rice systems, developing site-specific technology packages, ascertaining synergies with productivity, and accounting for N2O emissions

Audio watermarking: features, applications and algorithms

Abstract: This paper considers the desired properties and possible applications of audio watermarking algorithms. Special attention is given to statistical methods working in the Fourier domain. It presents a solution to robust watermarking of audio data and reflects the security properties of the technique. Experimental results show good robustness of the approach against MP3 compression and other common signal processing manipulations. Enhancements to the presented methods are discussed.

Vinyl chloride: still a cause for concern.

Abstract: Vinyl chloride (VC) is both a known carcinogen and a regulated chemical, and its production capacity has almost doubled over the last 20 years, currently 27 million tons/year worldwide. According to recent reports it is still a cause for concern. VC has been found as a degradation product of chloroethylene solvents (perchloroethylene and trichloroethylene) and in landfill gas and groundwater at concentrations up to 200 mg/m(3) and 10 mg/L, respectively. Worldwide occupational exposure to VC still seems to be high in some countries (e.g., averages of approximately 1,300 mg/m(3) until 1987 in one factory), and exposure may also be high in others where VC is not regulated. By combining the most relevant epidemiologic studies from several countries, we observed a 5-fold excess of liver cancer, primarily because of a 45-fold excess risk from angiosarcoma of the liver (ASL). The number of ASL cases reported up to the end of 1998 was 197 worldwide. The average latency for ASL is 22 years. Some studies show a small excess risk for hepatocellular carcinoma, and others suggest a possible risk of brain tumors among highly exposed workers. Lung cancer, lymphomas, or leukemia do not seem to be related to VC exposure according to recent results. The mutation spectra observed in rat and human liver tumors (ASL and/or hepatocellular carcinoma) that are associated with exposure to VC are clearly distinct from those observed in sporadic liver tumors or hepatic tumors that are associated with other exposures. In rats, the substitution mutations found at A:T base pairs in the ras and p53 genes are consistent with the promutagenic properties of the DNA adduct 1,N(6)-ethenoadenine formed from VC metabolites. Risk assessments derived from animal studies seem to overestimate the actual risk of cancer when comparing estimated and reported cases of ASL.

Component-based product line development: the KobrA approach

Abstract: The product line and component-based approaches to software engineering both hold the potential to significantly increase the level of reuse in industrial software development and maintenance. They also have complementary strengths, since they address the problem of reuse at opposite ends of the granularity spectrum; product line development essentially supports “reuse in the large” while component based development supports “reuse in the small.” This paper describes a method, Kobr A, that cleanly integrates the two paradigms into a systematic, unified approach to software development and maintenance. Key synergies resulting from this integration include support for the rapid and flexible instantiation of system variants, and the provision of methodological support for component-based framework development.

Large deflection micromechanical scanning mirrors for linear scans and pattern generation

Abstract: An electrostatically driven silicon micro scanning mirror (MSM) for one-dimensional (1-D) and two-dimensional (2-D) deflection of light is presented. A special configuration of the driving electrodes allows the use of small electrode gaps without restricting the deflection of the plate geometrically. In this paper, the starting of the oscillation and the operation of the scanner is discussed. Experimental results show that scan angles of up to 60/spl deg/ can be achieved at a driving voltage of only 20 V. The 2-D deflection of a laser beam is obtained by a gimbal mounting of the mirror plate. For the fabrication of the devices, SOI-wafers are used as the base material. The mechanical structures are defined by a deep silicon etch. For the electrical isolation of areas on the movable frame, polysilicon-filled trenches are used. The mechanical stability of the scanners is tested. The devices resist shocks of more than 1000 g and show no change of the resonance frequency even after long run tests of 7/spl times/10/sup 9/ periods.

A comprehensive evaluation of capture-recapture models for estimating software defect content

Abstract: An important requirement to control the inspection of software artifacts is to be able to decide, based on more objective information, whether the inspection can stop or whether it should continue to achieve a suitable level of artifact quality. A prediction of the number of remaining defects in an inspected artifact can be used for decision making. Several studies in software engineering have considered capture-recapture models to make a prediction. However, few studies compare the actual number of remaining defects to the one predicted by a capture-recapture model on real software engineering artifacts. The authors focus on traditional inspections and estimate, based on actual inspections data, the degree of accuracy of relevant state-of-the-art capture-recapture models for which statistical estimators exist. In order to assess their robustness, we look at the impact of the number of inspectors and the number of actual defects on the estimators' accuracy based on actual inspection data. Our results show that models are strongly affected by the number of inspectors, and therefore one must consider this factor before using capture-recapture models. When the number of inspectors is too small, no model is sufficiently accurate and underestimation may be substantial. In addition, some models perform better than others in a large number of conditions and plausible reasons are discussed. Based on our analyses, we recommend using a model taking into account that defects have different probabilities of being detected and the corresponding Jackknife Estimator. Furthermore, we calibrate the prediction models based on their relative error, as previously computed on other inspections. We identified theoretical limitations to this approach which were then confirmed by the data.

Dynamics of Dissolved Organic Carbon and Methane Emissions in a Flooded Rice Soil

Abstract: Limited information is available on the dynamics of dissolved organic C (DOC) and its relationship with CH, emissions in flooded rice (Oryza sativa L.) soils as affected by rice cultivar. Greenhouse and laboratory experiments were conducted to determine root C release in culture solution, DOC and dissolved CH 4 concentration in soil solution, and CH 4 emission in a flooded soil planted with three rice cultivars. Soil solutions were sampled in the root zone (soil surrounding rice roots) and the non-root zone (soil outside the root zone). The release of root exudates increased in the order: IR65598 (new plant type) < IR72 (modern cultivar) < Dular (a traditional cultivar). Correspondingly, DOC concentrations in the root zone and CH 4 emission rates increased. The dynamics of DOC and dissolved CH 4 differed greatly between the root zone and the non-root zone. Dissolved organic C in the root zone increased with plant growth and reached maximum (13-24 mmol C L -1 ) between rice flowering and maturation (Week 11-13), whereas DOC in the non-root zone remained low (1-5 mmol C L -1 ) throughout the growing season. Similarly, dissolved CH 4 concentrations in the root zone increased sooner and were greater (mean 138 μmol CH 4 L -1 ) than those in the non-root zone (mean 97 μmol CH 4 L -1 ). The seasonal patterns of CH 4 emissions closely followed the dynamics of DOC concentrations in the root zone. The results suggest that (i) DOC pool in the root zone of rice plants is enriched by root-derived C; (ii) the rates of CH 4 emissions are positively correlated with the dynamics of DOC in the root zone; (iii) the intercultivar difference in root C releases is responsible for the intercultivar difference in DOC production, and consequently in CH 4 flux.

Methane emission from irrigated and intensively managed rice fields in Central Luzon (Philippines)

Abstract: Methane (CH4) emissions were measured with an automated system in Central Luzon, the major rice producing area of the Philippines. Emission records covered nine consecutive seasons from 1994 to 1998 and showed a distinct seasonal pattern: an early flush of CH4 before transplanting, an increasing mend in emission rates reaching maximum toward grain ripening, and a second flush after water is withdrawn prior to harvesting. The local practice of crop management, which consists of continuous flooding and urea application, resulted in 79-184 mg CH4 m’ d-’ in the dry season (DS) and 269–503 mg CH4 m-2 d-1 in the wet season (WS). The higher emissions in the WS may be attributed to more labile carbon accumulation during the dry fallow period before the WS cropping as shown by higher % organic C. incorporation of sulfate into the soil reduced CH4 emission rates. The use of ammonium sulfate as N fertilizer in place of urea resulted in a 25-36% reduction in CH4 emissions. Phosphogypsum reduced CH4 emissions by 72% when applied in combination with urea fertilizer. Midseason drainage reduced CH4 , emission by 43%, which can be explained by the influx of oxygen into the soil. The practice of direct seeding instead of transplanting resulted in a 16–54ik reduction in CH4 emission, but the mechanisms for the reducing effect are not clear. Addition of rice straw compost increased CH4 emission by only 23-30% as compared with the 162-250% increase in emissions with the use of fresh rice straw. Chicken manure combined with urea did not increase CH4 emission. Fresh rice straw has wider C/N (25 to 45) while rice straw compost has C/N = 6 to 10 and chicken manure has C/N = 5 (o 8. Modifications in inorganic and organic fertilizer management and water regime did not adversely affect grain yield and are therefore potential mitigation options. Direct seeding has a lower yield potential than transplanting but is getting increasingly popular among farmers due to labor savings. Combined with a package of technologies, CH4 emission can best be reduced by (1)the practice of midseason drainage instead of continuous flooding,(2) the use of sulfate-containing fertilizers such as ammonium sulfate and phosphogypsum combined with urea; (3) direct seeding crop establishment; and (4) use of low C/N organic fertilizer such as chicken manure and rice straw compost.

Theory and arrangements of self-calibrating whole-body 3-D-measurement systems using fringe projection technique

Abstract: We report the basic concepts and experimental arrange- ments of self-calibrating 3-D measurement systems using structured- light illumination (fringe projection), which ensure a high number of ob- ject points, rapid data acquisition, and a simultaneous determination of coordinates and system parameters (self-calibration), making the system completely insensitive to environmental changes. Furthermore, it is un- necessary to have any marker on the object surface and a subsequent matching of the single views is not required to obtain a full-body mea- surement. For this purpose, the test object is successively illuminated with two grating sequences perpendicular to each other from at least two different directions, resulting in surplus phase values for each measure- ment point. Based on these phase values one can calculate the orienta- tion parameters as well as the 3-D coordinates simultaneously. Different measurement setups that have the ability to measure the entire surface (full-body measurement) are reported. Results are presented showing the power of this concept, for example, by measuring of the complete 3-D shape of specular technical surfaces, whereas the object volumes can differ strongly. Theoretical estimations proven by first measurements show a coordinate measurement accuracy of up to 10 25 of the measure- ment field size. © 2000 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(00)01801-8)

A feature-based approach towards an integrated product model including conceptual design information

Abstract: Due to the highly complex and informal data that has to be managed in the conceptual design this early design phase still lacks of suitable computer support. Furthermore, existing approaches towards a computer aided conceptual design are insufficiently integrated with the downstream applications of the product development process. The paper therefore introduces an approach towards a feature-based integrated product model that incorporates a feature-based representation scheme for capturing product semantics handled in the conceptual design phase and links early design with part and assembly modelling.

A Short History of Cleaning Robots

Abstract: The definition of the desired functions and the design of an ultimate versatile personal robot is an ongoing debate. Meanwhile, however, precursors of this yet to evolve species are well on their way to become commercial products. Cleaning robots for public environments as well as for private households seem to be able to provide the breakthrough which the designers of non-industrial robot systems have long awaited. This survey describes a selection of 30 different cleaning robots, with the first developments reaching back more than 15 years. With a few exceptions we have focused on floor cleaning, in particular indoor floor cleaning. We describe a variety of scrubbing and vacuuming robots which were developed for this task. The described systems range from heavy, large, and expensive industrial cleaning vehicles to small-size, light-weight, low-cost household devices. The survey does not include, however, systems for cleaning facades of buildings, or windows, or production tools. Although not all of the 30 cleaning robots abovementioned have yet reached the state of commercial products, their number alone certainly reflects the expectations regarding the economic value associated with the automation of cleaning tasks. In Europe only the estimates for the market for cleaning services range up to the order of USd 100 billion per year. It is therefore not surprising that the cleaning industry and the manufacturers of cleaning devices are rather enthusiastic with respect to the automation of cleaning tasks using (semi-)autonomous mobile robot systems.

A comparative study of two software development cost modeling techniques using multi-organizational and company-specific data

Abstract: This research examined the use of the International Software Benchmarking Standards Group (ISBSG) repository for estimating effort for software projects in an organization not involved in ISBSG. The study investigates two questions: (1) What are the differences in accuracy between ordinary least-squares (OLS) regression and Analogy-based estimation? (2) Is there a difference in accuracy between estimates derived from the multi-company ISBSG data and estimates derived from company-specific data? Regarding the first question, we found that OLS regression performed as well as Analogy-based estimation when using company-specific data for model building. Using multi-company data the OLS regression model provided significantly more accurate results than Analogy-based predictions. Addressing the second question, we found in general that models based on the company-specific data resulted in significantly more accurate estimates.

Novel Metallic Hollow Sphere Structures

Abstract: The obvious advantages of metallic hollow sphere materials have lead to several attempts to produce such structures. None of these approaches has gained practical significance owing to the very high cost of the methods. A new powder metallurgical process using styrofoam spheres allows for the production of hollow spheres from arbitrary metals and alloys. The IFAM Department of Powder Metallurgy and Composite Materials, Dresden, has developed this process and added a method that produces random hollow sphere structures (RHS) directly from the green spheres.

Radiation filters and emitters for the NIR based on periodically structured metal surfaces

Abstract: The spectrally selective optical properties of wavelength selective radiation emitters and filters based on periodically microstructured metal surfaces were investigated. Metal surfaces were structured by the use of a holographic mask and subsequent etching processes. Due to the microstructure, thermally excited surface plasmons couple to electromagnetic radiation. Therefore a structured tungsten surface can act as a selective radiation emitter. The calculation of the absorptance by a rigorous diffraction theory allows the prediction of the emissivity of such structures. The angle dependent emissivity of tungsten gratings with periods of 1.4 μm and 2.0 μm was measured. A peak emissivity of 70% at a wavelength of 1.6 μm was achieved. Band pass filters for the near infrared spectral range based on perforated metal films were investigated theoretically and experimentally. Filters with a grating period of 2.0 μm were produced. A peak transmittance of 80% at a wavelength 2.9 μm was achieved. The optic...