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1.
Lauri PuroAuthor VitaeJeffrey E. TeichAuthor Vitae Hannele WalleniusAuthor VitaeJyrki WalleniusAuthor Vitae 《Decision Support Systems》2011,51(1):31-41
We define and identify bidding strategies in real-life small loan auctions (Prosper.com). In such auctions, lenders bid for borrowers' loan listings and the winners get to fund the loan at an interest rate determined by the auction. The exceptionally large empirical database provided by Prosper.com offers a unique opportunity to test and further develop the theory of online auctions. This study shows that bidding behavior is not homogeneous among bidders, as the traditional auction theory suggests. Instead, bidders use many different bidding strategies. Moreover, learning and bidders' consistency over time in different auctions is studied. 相似文献
2.
The use of building information modelling (BIM) and related software tools is increasingly expanding in the work of site managers in construction projects. The early uses of BIM in the actual tasks of site managers are explored by examining the utilization of BIM in their work and the challenges in the deployment of the new digital tools for traditional project collaboration. The ethnographic method of the study consists of shadowing the site managers’ work. The site managers actively used BIM and found it beneficial for their daily work. However, the use of BIM in construction sites is still limited because only a few managers have the competence to use BIM software tools, mobile tools are lacking, and the information content of the models needed for construction work is insufficient. 相似文献
3.
Hannele Holttinen 《风能》2005,8(2):173-195
Studies of the effects that wind power production imposes on the power system involve assessing the variations of large‐scale wind power production over the whole power system area. Large geographical spreading of wind power will reduce variability, increase predictability and decrease the occasions with near zero or peak output. In this article the patterns and statistical properties of large‐scale wind power production data are studied using the data sets available for the Nordic countries. The existing data from Denmark give the basis against which the data collected from the other Nordic countries are benchmarked. The main goal is to determine the statistical parameters describing the reduction of variability in the time series for the different areas in question. The hourly variations of large‐scale wind power stay 91%–94% of the time within ±5% of installed capacity in one country, and for the whole of the Nordic area 98% of the time. For the Nordic time series studied, the best indicator of reduced variability in the time series was the standard deviation of the hourly variations. According to the Danish data, it is reduced to less than 3% from a single site value of 10% of capacity. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
4.
Characteristics of day‐ahead wind power forecast errors in Nordic countries and benefits of aggregation 下载免费PDF全文
The growing proportion of wind power in the Nordic power system increases day‐ahead forecasting errors, which have a link to the rising need for balancing power. However, having a large interconnected synchronous power system has its benefits, because it enables to aggregate imbalances from large geographical areas. In this paper, day‐ahead forecast errors from four Nordic countries and the impacts of wind power plant dispersion on forecast errors in areas of different sizes are studied. The forecast accuracy in different regions depends on the amount of the total wind power capacity in the region, how dispersed the capacity is and the forecast model applied. Further, there is a saturation effect involved, after which the reduction in the relative forecast error is not very large anymore. The correlations of day‐ahead forecast errors between areas decline rapidly when the distance increases. All error statistics show a strong decreasing trend up to the area sizes of 50,000 km2. The average mean absolute error (MAE) in different regions is 5.7% of installed capacity. However, MAE of a smaller area can be over 8% of the capacity, but when all the Nordic regions are aggregated together, the capacity‐normalized MAE decreases to 2.5%. The average of the largest errors for different regions is 39.8% and when looking at the largest forecast errors for smaller areas, the largest errors can exceed 80% of the installed capacity, whereas at the Nordic level, the maximum forecast error is only 13.5% of the installed capacity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Hannele Holttinen Peter Meibom Antje Orths Bernhard Lange Mark O'Malley John Olav Tande Ana Estanqueiro Emilio Gomez Lennart Söder Goran Strbac J Charles Smith Frans van Hulle 《风能》2011,14(2):179-192
There are dozens of studies made and ongoing related to wind integration. However, the results are not easy to compare. IEA WIND R&D Task 25 on ‘Design and Operation of Power Systems with Large Amounts of Wind Power’ collects and shares information on wind generation impacts on power systems, with analyses and guidelines on methodologies. In the state‐of‐the‐art report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of wide areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than day‐ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
Anna‐Marja Aura Sirpa Karppinen Hannele Virtanen Pirkko Forssell Satu‐Maarit Heinonen Tarja Nurmi Herman Adlercreutz Kaisa Poutanen 《Journal of the science of food and agriculture》2005,85(12):2085-2093
Plant lignans are converted to mammalian forms, enterodiol and enterolactone, in the colon. Enhanced plasma or urinary enterolactone levels have been associated with lowered risk of cardiovascular diseases and breast cancer. Processed rye bran and its fractions were compared to ascertain the fermentation rates of fermentable carbohydrates and the bioconversion of lignans. Rye bran was extruded and treated with a food‐grade xylanase. Part of the xylanase‐treated rye bran was separated into a soluble rye bran extract and an insoluble residue, and a part of the xylanase‐treated rye bran was freeze‐dried without separation. All the samples were digested by pepsin and pancreatin and subsequently fermented with a human faecal inoculum in vitro. The consumption of carbohydrates, the productions of short‐chain fatty acids (SCFA), enterodiol and enterolactone were followed as a function of time. The soluble rye bran extract showed the fastest fermentation rate and the highest extent of fermentation determined as the consumption of neutral sugar residues (arabinose, xylose and glucose), the production of SCFA and the formation of enterodiol and enterolactone. Xylanase treatment enhanced the fermentation rate of extruded rye bran. An even a higher fermentation rate was observed for rye bran extract containing soluble carbohydrates. The amount of enterolactone precursors in rye seemed to be too low for enterolactone formation using an amount of substrate suitable for carbohydrate fermentation. However, xylanase treatment enhanced the availability of plant lignans from rye bran, as enterodiol formation was increased by the use of xylanase. Copyright © 2005 Society of Chemical Industry 相似文献
7.
Jaana M. Kusnetsov Pertti J. Martikainen Hannele R. Jousimies-Somer Marja-Liisa Visnen Arto I. Tulkki Henry E. Ahonen Aino I. Nevalainen 《Water research》1993,27(1)
The occurrence of Legionella in water of 30 cooling tower systems was studied, as well as the relationship of its occurrence with the physical, chemical and microbiological characteristics of the waters. The samples were concentrated by membrane filtration and one part of the concentrate was acid washed. Three types of culture media, MWY, CCVC and BCYEα were used. Fourteen (47%) of the cooling systems were Legionella-positive. Numbers of Legionella in the positive systems varied between 50 and 490,000 cfu/l. Legionella pneumophila was the dominant isolate, and the serogroups 6 and 1 were the commonest ones. There was no statistically significant difference in mean water temperature between the Legionella-positive (27°C) and -negative (24°C) systems. The total number of bacteria (AODC) was lower in the Legionella-positive than in the negative systems. Also the nutrient concentrations were generally lower in the Legionella-positive cooling systems. The results suggest that different factors regulate the occurrence of Legionella than that of overall bacterial populations in the cooling tower systems. 相似文献
8.
Rational and participative task allocation between the nursing staff and the logistics support service provider in healthcare 下载免费PDF全文
This study aims to answer how rational task allocation between the nursing staff and the support service provider in the healthcare context can increase the positive outcome of the work system. The work system model is used as a theoretical framework, with resilience and cost as complementary concepts. This qualitative case study used action research and participatory design to develop the work system with the interplay of two parallel personnel groups in the healthcare environment. First, the case of an ongoing relationship between the target organization's nursing staff and in‐house logistics and material supply services was studied. The development process resulted in a variety of practical ideas to improve the cooperation between the personnel groups. In the second case, a prospective relationship between the nursing staff and an external logistics service provider was examined. This research's conceptual results identify the main characteristics of rational support services as comprehensive, resilient, reliable, and easily accessible. 相似文献
9.
Antti A Mero Heikki Huovinen Olle Matintupa Juha J Hulmi Risto Puurtinen Hannele Hohtari Tuomo AM Karila 《Journal of the International Society of Sports Nutrition》2010,7(1):1-11
Background
Intense exercise induces increased blood neutrophil counts and decreased lymphocyte counts, and leads to inflammation and immunosuppression. It was previously reported that cystine and theanine (CT) supplementation by long-distance runners before a training camp suppressed the changes of these blood parameters observed in un-supplemented control subjects after the camp. The purpose of the present study was to determine the effects of CT supplementation on the inflammatory response and immune state before and after intense endurance exercise in long-distance runners at a training camp.Methods
Sixteen long-distance runners were allocated to one of two groups given CT supplements (700 mg cystine + 280 mg theanine daily) or placebo (8 in each group) for 7 days prior to and during a 9-day training camp. Daily run training averaged 19.9 km/day prior to the camp and 28.6 km/day during the camp. On the initial and final days of the camp, blood samples were collected before and after 15 km morning interval running workouts (1000 m × 15 times) and analyzed for neutrophil and lymphocyte counts and myoglobin.Results
The relative change in exercise-induced blood neutrophil count (% of pre-exercise values) was significantly lower in the CT group than in the placebo group (163.3 ± 43.2% vs. 200.4 ± 19.6%, p = 0.044) on the initial day of camp, but not on the last day. The decline in lymphocyte count (% of pre-exercise values) was significantly less in the CT group than in the placebo group (60.2 ± 19.2% vs. 36.2 ± 12.0%, p = 0.010) on the initial day of camp, but not on the last day. In blood myoglobin, there was a trend toward lower % of pre-exercise values in the CT group (p < 0.09) on both measurement days.Conclusion
CT supplementation significantly attenuated the increase in neutrophil count and the reduction in lymphocyte count induced by intense endurance exercise. These results suggest that CT supplementation may suppress the exercise-induced fluctuation of the blood immunocompetent cells and may help to reduce the alteration of the immune state. 相似文献10.
Rainer M. Hadlok Hannele Harju Ernst Ludwig Sattler und Gabriele Wagner 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,191(6):454-458
Zusammenfassung Die Belastung mit134+137 Caesium von in Hessen erlegtem Schalenwild (556 Stück 1986/87) nach dem Reaktorunfall von Tschernobyl wurde untersucht. Es werden Vergleiche zu der Situation vorher (1981–1983) und bis zu der heutigen Belastung (bis Juni 1989) in Abhängigkeit von der Herkunft der Tiere gezogen. Bei der insgesamt verhältnismäßig geringen Caesiumkontamination waren die verschiedenen Tierarten unterschiedlich betroffen, Rotwild war im Durchschnitt am stärksten belastet (130 Bq/kg). Den größten Einfluß auf die Höhe der Belastung des Wildes hatte die Herkunft der Tiere, es spielten sowohl regionale als auch geographische und meteorologische Bedingungen eine große Rolle. Ein Einfluß von Alter bzw. Geschlecht der Tiere auf die Wildbretkontamination konnte nicht festgestellt werden. Die zeitliche Entwicklung der Caesiumbelastung zeigte eine deutlich fallende Tendenz.
Investigations on caesium 134 and 137 contamination of game hunted for food in Hessia
Summary The amount of caesium 134 and 137 in Hessian game hunted for food (556 animals) after the reactor accident at Chernobyl was investigated. Comparisons have been made before and after the accident. Although there was only a very low level of contamination, the contamination rate of different species varied; on average, the Red Deer showed the highest activity (130 Bq/kg). The level of caesium contamination was mostly influenced by the permanent habitat of the animals. The main influence was due to regional, geographical and meteorological conditions. The influence of age or sex could not be determined. The contamination rate was shown to decrease with time.相似文献