109 research outputs found
RePLEX: A Model-Based Reengineering Tool for PLEX Telecommunication Systems
Maintenance of complex legacy software systems is a challenging task. In the first place, maintenance requires understanding the system. Reverse engineering and reengineering tools, which make the design of the current system available on-line and which support planning and performing changes to the system, are urgently needed. We present a new tool for reengineering telecommunication systems, recovering the current architecture, and extracting state machines reflecting the system behavior. The tool is based on a structure graph of the architecture and allows architectural modifications with according code changes. The modifications are specified as graph transformations using FUJABA enabling the generation of a Java prototype, which is accessible via a GUI based on the Graphical Editor Framework (GEF) plug-in for the Eclipse workbench
Investment dynamics in the energy sector under carbon price uncertainty and risk aversion
Decarbonizing the electricity system in order to contribute to climate change mitigation is a key policy goal. Yet, uncertain political and economic conditions (e.g., electricity prices) create uncertainty for energy companies. The dynamics of carbon price developments and aversion to uncertainty may have decisive impacts on companies’ investment decisions and thus environmental and distributional outcomes. In this paper, we incorporate a dynamic portfolio approach in a simulation model of investments in the electricity sector to explore and disentangle the impacts of both uncertainty and risk aversion on companies’ investment decisions. We find that policy uncertainty and risk aversion tend to delay the transition to a low-carbon energy system, with higher levels of either factor causing even further delays. However, the mechanism for the delay depends on how risk aversion is modeled, e.g. whether companies are averse to losses, or variances or if they use a higher discount rate in uncertain situations. Employing the loss-averse approach, the company prefers technology with a low likelihood of negative returns for the portfolio; meanwhile, the mean-variance approach indicates an aversion to both positive and negative deviations in returns. With a high discount rate, investors favor less capital-intensive technologies. To account for the impact of risk aversion in policy framework we, therefore, need more empirical work on understanding these behavioral traits of energy companies
Evaluation of hydropower upgrade projects - a real options approach
When evaluating whether to refurbish existing hydropower plants or invest in a new power plant, there are two important aspects to take into consideration. These are the capacity chosen for the production facilities and the timing of the investment. This paper presents an investment decision support framework for hydropower producers with production facilities due for restoration. The producer can choose between refurbishing existing power plants and investing in a new production facility. A real options framework is proposed to support the investment decision. Using a case from Norsk Hydro ASA, a Norwegian hydropower producer, we employ the framework to evaluate the investment opportunities. Our main contribution is an approach that combines hydropower scheduling and real options valuation, and the results from our analysis suggest feasible investment strategies for Norsk Hydro ASA.Electricity price uncertainty; reservoir management; hydroelectric scheduling; investment under uncertainty; electricity markets
Gas chromatography vs. quantum cascade laser-based N<sub>2</sub>O flux measurements using a novel chamber design
Recent advances in laser spectrometry offer new opportunities to
investigate the soil–atmosphere exchange of nitrous oxide. During two field
campaigns conducted at a grassland site and a willow field, we tested the
performance of a quantum cascade laser (QCL) connected to a newly developed
automated chamber system against a conventional gas chromatography (GC)
approach using the same chambers plus an automated gas sampling unit with
septum capped vials and subsequent laboratory GC analysis. Through its high
precision and time resolution, data of the QCL system were used for
quantifying the commonly observed nonlinearity in concentration changes
during chamber deployment, making the calculation of exchange fluxes more
accurate by the application of exponential models. As expected, the curvature
values in the concentration increase was higher during long (60 min) chamber
closure times and under high-flux conditions
(FN2O > 150 µg N m−2 h−1)
than those values that were found when chambers were closed for only 10 min and/or
when fluxes were in a typical range of 2 to
50 µg N m−2 h−1. Extremely low standard errors of
fluxes, i.e., from  ∼  0.2 to 1.7 % of the flux value, were observed
regardless of linear or exponential flux calculation when using QCL data.
Thus, we recommend reducing chamber closure times to a maximum of 10 min
when a fast-response analyzer is available and this type of chamber system is
used to keep soil disturbance low and conditions around the chamber plot as
natural as possible. Further, applying linear regression to a 3 min data
window with rejecting the first 2 min after closure and a sampling time
of every 5 s proved to be sufficient for robust flux determination while ensuring
that standard errors of N2O fluxes were still on a relatively low level.
Despite low signal-to-noise ratios, GC was still found to be a useful method
to determine the mean the soil–atmosphere exchange of N2O on longer timescales
during specific campaigns. Intriguingly, the consistency between GC and
QCL-based campaign averages was better under low than under high N2O
efflux conditions, although single flux values were highly scattered during
the low efflux campaign. Furthermore, the QCL technology provides a useful
tool to accurately investigate the highly debated topic of diurnal courses
of N2O fluxes and its controlling factors. Our new chamber design
protects the measurement spot from unintended shading and minimizes
disturbance of throughfall, thereby complying with high quality requirements
of long-term observation studies and research infrastructures
Evaluation of hydropower upgrade projects - a real options approach
When evaluating whether to refurbish existing hydropower plants or invest in a new power plant, there are two important aspects to take into consideration. These are the capacity chosen for the production facilities and the timing of the investment. This paper presents an investment decision support framework for hydropower producers with production facilities due for restoration. The producer can choose between refurbishing existing power plants and investing in a new production facility. A real options framework is proposed to support the investment decision. Using a case from Norsk Hydro ASA, a Norwegian hydropower producer, we employ the framework to evaluate the investment opportunities. Our main contribution is an approach that combines hydropower scheduling and real options valuation, and the results from our analysis suggest feasible investment strategies for Norsk Hydro ASA
Evaluation of hydropower upgrade projects - a real options approach
When evaluating whether to refurbish existing hydropower plants or invest in a new power plant, there are two important aspects to take into consideration. These are the capacity chosen for the production facilities and the timing of the investment. This paper presents an investment decision support framework for hydropower producers with production facilities due for restoration. The producer can choose between refurbishing existing power plants and investing in a new production facility. A real options framework is proposed to support the investment decision. Using a case from Norsk Hydro ASA, a Norwegian hydropower producer, we employ the framework to evaluate the investment opportunities. Our main contribution is an approach that combines hydropower scheduling and real options valuation, and the results from our analysis suggest feasible investment strategies for Norsk Hydro ASA
rs1004819 Is the Main Disease-Associated IL23R Variant in German Crohn's Disease Patients: Combined Analysis of IL23R, CARD15, and OCTN1/2 Variants
The IL23R gene has been identified as a susceptibility gene for inflammatory bowel disease (IBD) in the North American population. The aim of our study was to test this association in a large German IBD cohort and to elucidate potential interactions with other IBD genes as well as phenotypic consequences of IL23R variants. Genomic DNA from 2670 Caucasian individuals including 833 patients with Crohn's disease (CD), 456 patients with ulcerative colitis (UC), and 1381 healthy unrelated controls was analyzed for 10 IL23R SNPs. Genotyping included the NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C-->T) and SLC22A5/OCTN2 (-207 G-->C). All IL23R gene variants analyzed displayed highly significant associations with CD. The strongest association was found for the SNP rs1004819 [P = 1.92x10(-11); OR 1.56; 95 % CI (1.37-1.78)]. 93.2% of the rs1004819 TT homozygous carriers as compared to 78% of CC wildtype carriers had ileal involvement [P = 0.004; OR 4.24; CI (1.46-12.34)]. The coding SNP rs11209026 (p.Arg381Gln) was protective for CD [P = 8.04x10(-8); OR 0.43; CI (0.31-0.59)]. Similar, but weaker associations were found in UC. There was no evidence for epistasis between the IL23R gene and the CD susceptibility genes CARD15 and SLC22A4/5. IL23R is an IBD susceptibility gene, but has no epistatic interaction with CARD15 and SLC22A4/5. rs1004819 is the major IL23R variant associated with CD in the German population, while the p.Arg381Gln IL23R variant is a protective marker for CD and UC
Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe's terrestrial ecosystems : a review
Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.Peer reviewe
International Olympic Committee consensus statement on pain management in elite athletes
Pain is a common problem among elite athletes and is frequently associated with sport injury. Both pain and injury interfere with the performance of elite athletes. There are currently no evidence-based or consensus-based guidelines for the management of pain in elite athletes. Typically, pain management consists of the provision of analgesics, rest and physical therapy. More appropriately, a treatment strategy should address all contributors to pain including underlying pathophysiology, biomechanical abnormalities and psychosocial issues, and should employ therapies providing optimal benefit and minimal harm. To advance the development of a more standardised, evidence-informed approach to pain management in elite athletes, an IOC Consensus Group critically evaluated the current state of the science and practice of pain management in sport and prepared recommendations for a more unified approach to this important topic
Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe´s terrestrial ecosystems: a review."
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