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41.
In this paper we propose a novel approach for intuitive and natural physical human–robot interaction in cooperative tasks. Through initial learning by demonstration, robot behavior naturally evolves into a cooperative task, where the human co-worker is allowed to modify both the spatial course of motion as well as the speed of execution at any stage. The main feature of the proposed adaptation scheme is that the robot adjusts its stiffness in path operational space, defined with a Frenet–Serret frame. Furthermore, the required dynamic capabilities of the robot are obtained by decoupling the robot dynamics in operational space, which is attached to the desired trajectory. Speed-scaled dynamic motion primitives are applied for the underlying task representation. The combination allows a human co-worker in a cooperative task to be less precise in parts of the task that require high precision, as the precision aspect is learned and provided by the robot. The user can also freely change the speed and/or the trajectory by simply applying force to the robot. The proposed scheme was experimentally validated on three illustrative tasks. The first task demonstrates novel two-stage learning by demonstration, where the spatial part of the trajectory is demonstrated independently from the velocity part. The second task shows how parts of the trajectory can be rapidly and significantly changed in one execution. The final experiment shows two Kuka LWR-4 robots in a bi-manual setting cooperating with a human while carrying an object. 相似文献
42.
Kunesová M Hainer V Tvrzicka E Phinney SD Stich V Parízková J Zák A Stunkard AJ 《Lipids》2002,37(1):27-32
Fourteen pairs of obese female monozygotic twins were recruited for a study of genetic influences on serum and adipose fatty
acid (FA) composition. Following 1 wk of inpatient stabilization, fasting serum and adipose tissue obtained by surgical excision
were analyzed by thin-layer and gas chromatography. Intrapair resemblances (IPR) for individual FA were assessed by Spearman
rank correlation and by analysis of variance and were found in serum cholesteryl esters (CE), triglycerides (TG), and adipose
TG. With two exceptions (CE linoleate and adipose eicosapentaenoate), these IPR were limited to the nonessential FA. Palmitate
had significant IPR in four lipid fractions; in serum CE and adipose TG palmitate was strongly correlated with multiple measures
of adiposity. In contrast to other lipid fractions, serum phosphatidylcholine (PC) FA had 12 IPR, of which 6 were essential
FA including arachidonate (r=0.76, P<0.0005), eicosapentaenoate (r=0.78, P<0.0005), and docosahexaenoate (r=0.86, P<0.0001). The PC IPR could not be explained by analysis of preadmission 7-d food records. After dividing the pairs into two
groups differing and nondiffering according to fat intake of individuals in the pair, there was no evidence of a gene-environment
interaction between fat intake and FA composition. The IPR for nonessential FA indicate that there is active genetic control
of either food choices or postabsorptive metabolic processing. The high level of IPR in the PC fraction in contrast to the
other lipid fractions suggests strong genetic influence over selection of specific FA for this membrane fraction independent
of diet. 相似文献
43.
Reduction of NO in 2–8M HClO4 and 2 M HCl at E ? 0.35V on platinized and smooth platinum electrodes is a diffusion-controlled process. On freshly activated electrodes the reduction in this potential region involves one-electron reaction to form N2O, as well as multiple-electron reduction yielding NH4+ and NH3OH+. The product composition is largely dependent on the degree of electrode deactivation. 相似文献
44.
The paper argues that attitudes to SOA follow a typical hype cycle from Technological Trigger, Peak of Inflated Expectations, and a Trough of Disillusionment to the more recent realization that SOA is a concept that may offer certain benefits but has several limitations. The main research question studies how the attitude to SOA changes in various phases of the hype cycle, how the SOA implementation cycle and an increase in business process maturity (BPMa) are interconnected and which factors influence the transition between the hype cycle phases. The paper shows that an organization??s success with implementing SOA depends on its ability to match the SOA implementation with an increase in BPMa. The dual purpose of implementing SOA is shown in the first framework: to assure the coherence of IT assets and to assure business/IT alignment. In the second framework, the interconnection of SOA and BPMa and its role in transiting through the hype cycle phases is outlined. The findings are analyzed using a longitudinal case study of a large Slovenian company. 相似文献
45.
The purpose of this paper is to discuss the effect of financial-economic crisis on the equity value of companies, as well as present the importance of fair and honest company valuations. The fundamental value of equity capital of a company is important for both management and external shareholders. The wide disparity between market and fundamental values can lead to high value adjustments, which reduces investors confidence in the capital market. This has had a negative impact on the operations of financial institutions, and individual as well as company investment; especially on developing financial markets during a financial-economic crisis. This research was designed to assess the equity value of Slovenian public limited companies based on the discounted free cash flows to equity and comparing it with market value of equity capital of companies before and during the financial-economic crisis. The fundamental value of equity capital of the selected companies (sample of 25) is calculated using a two-tiered model. The paired-sample t-tests method rejected the hypothesis that the fundamental value of equity capital of Slovenian public limited companies better reflects the market value of equity capital in today’s times of financial-economic crisis (2011) than before the crisis (2006). However, we found that the market value of equity capital in relation to the fundamental value of equity capital of the selected companies was lower in 2011 than in 2006. Various models of the basic calculations are used in the model evaluation. This study shows the problem of company valuation on small and emerging capital markets which have a short history of data. 相似文献
46.
Patricia van Loon Charles Delagarde Luk N. Van Wassenhove Aleš Mihelič 《国际生产研究杂志》2020,58(4):1092-1106
Remanufacturing can create opportunities for companies to become more sustainable while remaining profitable. However, not all companies will be able to profit from moving towards a closed-loop business model. This paper investigates the profitability of leasing and remanufacturing washing machines for a large white goods producer based on data provided by them. A simple analytical model is built to simultaneously estimate the costs for consumers and costs and profits for the manufacturer under the leasing system. The results are compared with the costs and profitability of the linear system where premium, economy, and budget washing machines are sold to consumers. A sensitivity analysis is conducted on important factors such as repair, administration and transport costs. Using the replacement chain method, we show that the consumer costs of budget washing machines in the sales system is significantly higher than the costs for premium washing machines. Consequently, those consumers would benefit most from a circular system in which premium washing machines are leased against acceptable fees. However, the additional costs for the manufacturer make it a challenge to generate the same level of profit as in the linear system. The research discusses important cost components companies will have to address when making a move towards a circular business model with leasing and remanufacturing. 相似文献
47.
48.
Pheromones serve key functions in the biology of swarming locusts. However, research has focused largely on the mass-swarming desert locust, Schistocerca gregaria. We extended these investigations to the pheromonal profile of the rarely swarming American bird grasshopper, S. americana (Drury). The headspace of mature gregarious S. americana males contained three characteristic electroantennogram-active components: (Z)-3-nonen-1-ol, (Z)-2-octen-1-ol, and nonanal. These substances were accompanied by aromatics such as phenol that are also released by females and immatures. Male-specific pheromone components were released independently from epidermal gland cells, with the highest emission rate being for (Z)-3-nonen-1-ol from the abdomen and legs. The emission of the major compound, (Z)-3-nonen-1-ol, is stress-sensitive, and coincides with sexual maturity and crowding. The emission pattern strongly supports a role of (Z)-3-nonen-1-ol in the reproductive biology of S. americana. The pheromone is involved in courtship-inhibition and is used as mate assessment pheromone in cryptic female choice. In double mating experiments, females choose sperm of males with high (Z)-3-nonen-1-ol emission. Furthermore the pheromone accelerated maturation of immature adults and supports synchronization of sexual development. 相似文献
49.
Rupert Kargl Tamilselvan Mohan Stefan Köstler Stefan Spirk Aleš Doliška Karin Stana‐Kleinschek Volker Ribitsch 《Advanced functional materials》2013,23(3):308-315
Two different lithographic techniques for the patterning of thin biopolymer films are developed. The first method is based on using a microstructured elastomeric mold for the structuring of thin films of regenerated cellulose. The thin films are manufactured by spin‐coating of trimethylsilyl cellulose (TMSC) and subsequent regeneration. The microchannels formed by the mold and the cellulose film are filled with a cellulase solution by capillary action. In the areas exposed to the enzyme solution, the cellulose film is digested, whereas the area in contact with the mold is protected from the enzymatic activity. Optical thickness measurements, atomic force microscopy and fluorescent staining confirm a successful patterning of cellulose on several substrates by this method. The second method is based on the structured regeneration of thin TMSC films. TMSC surfaces are protected with metal masks and exposed to vapors of hydrochloric acid. These treatments result in hydrophilic cellulose structures surrounded by hydrophobic TMSC with differing physicochemical properties. Treatments of the obtained structures with cellulases allow the selective removal of pure cellulose, whereas a TMSC pattern remains on the surface. These TMSC can be regenerated back to pure cellulose by treatments with vapors of hydrochloric acid. The developed methods allow the effective fabrication of micropatterned biopolymer thin films suitable for further functionalization and application in, e.g., bioanalytical devices. This is shown by the immobilization and detection of single‐stranded DNA on structured cellulose surfaces. Owing to the versatility of both patterning approaches the methods can be further extended to other combinations of substrates and enzymes. 相似文献
50.
Ivan Holoubek Josef Čáslavsky Pavel Kořínek Klára Štaffová Jiří Kohoutek AleŠ Hrdlička 《Polycyclic Aromatic Compounds》2013,33(1-4):159-167
Abstract Concentrations of polyaromatic hydrocarbons (PAHs), chlorinated pesticides, polychlorinated biphenyls, dibenzo-p-dioxins and dibenzo-p-furans (PCDDs/Fs) in ambient air in Ko?etice, a background locality in the South Bohemia, have been estimated in the period from July to December 1994. The 24-hours samples have been taken by the means of a high-volume sampler. Sample analysis involved Soxhlet extraction of polyurethane foam, extract preconcentration and chromatographic clean-up procedure followed by HPLC determination of PAHs with fluorescence detection, GC/ECD determination of chlorinated pollutants, and GC/MS determination of PCDDs/Fs. The results of this first detailed study undertaken in Czech Republic are compared with the data obtained by similar projects in industrial and/or urban areas in the Czech Republic and in rural or urban areas in other European countries. 相似文献