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51.
Katerina Goševa-Popstojanova Ajay Deep Singh Sunil Mazimdar Fengbin Li 《Empirical Software Engineering》2006,11(1):71-117
The growing availability of Internet access has led to significant increase in the use of World Wide Web. If we are to design
dependable Web–based systems that deal effectively with the increasing number of clients and highly variable workload, it
is important to be able to describe the Web workload and errors accurately. In this paper we focus on the detailed empirical
analysis of the session–based workload and reliability based on the data extracted from actual Web logs of eleven Web servers.
First, we introduce and rigourously analyze several intra–session and inter–session metrics that collectively describe Web
workload in terms of user sessions. Then, we analyze Web error characteristics and estimate the request–based and session–based
reliability of Web servers. Finally, we identify the invariants of the Web workload and reliability that apply through all
data sets considered. The results presented in this paper show that session–based workload and reliability are better indicators
of the users perception of the Web quality than the request–based metrics. 相似文献
52.
In this paper we describe two projects on contextualized computer systems and audio augmented environments we are currently
working on at the Fraunhofer Institutes FIT and IMK. In this paper we will only focus on the world models and the augmentation
layer. Both projects are based on completely different technologies, and use different representation methods and interaction
facilities. While in hippie users are moving with small laptop computers or wearable computers with a small visual display,
in LISTEN users will have only a wireless headphone displaying spatially rendered sound-scenes.
Correspondence to: J. Goβmann, Fraunhofer-IMK, Schloss Birlinghoven, D-53754 St Augustin, Germany. 相似文献
53.
Noriaki Kurita Norihiko Fukatsu Teruo Ohashi Satoshi Miyamoto Fumiaki Sato Hiroyuki Nakai Kazuhiko Irie 《Metallurgical and Materials Transactions B》1996,27(6):929-935
We have developed a hydrogen sensor for in situ measurements of hydrogen activities in molten copper. The sensor consists of a concentration cell utilizing a proton conductor,
CaZr0.9In0.1O3-δ, as the solid electrolyte. The electromotive force (emf) of the cell was generated by both hydrogen and oxygen activity gradients
across the cell in a high-temperature region simulating the fire refining processes of copper. However, accurate hydrogen
activity in molten copper could be evaluated from the emf if oxygen activity in molten copper was determined simultaneously
by another concentration cell and if the hydrogen and the oxygen activities at the reference electrode were known. The performance
of the sensor was studied under various conditions. The observed good response and reliability of the sensor show that it
should be a powerful tool for improvement of the fire refining process of the molten copper. Theoretical treatment of the
calculation of the emf of the concentration cells using a mixed ionic conductor, i.e., protonic and oxide ionic conductor, as solid electrolytes is also discussed briefly. 相似文献
54.
K Dohmen T Shimada S Onohara M Shirahama Y Miyamoto K Irie H Ishibashi 《Canadian Metallurgical Quarterly》1998,89(9):277-281
A 63-year-old Japanese male with diabetes mellitus developed obstructive jaundice following the onset of multiple hepatic abscesses. Percutaneous transhepatic cholangiography showed intrahepatic bile duct irregularity and dilatations accompanied by a complete obstruction of the right branch of the intrahepatic bile duct. Three kinds of organisms were cultured from the blood and the drained bile. The cholangiographic changes returned to the normal after the liver abscesses subsided following biliary drainage and the administration of intravenous antibiotics. 相似文献
55.
A self-administered questionnaire study of 333 workers (male 253, female 80) in a manufacturing company was carried out one month after informing the workers of the results of their medical checkups in 1993. The questionnaire included several items such as recalled abnormal findings of health examination and ways of overcoming the abnormal findings, recalled results of their medical checkups in 1992, self-confidence in their recollection of the results, and the usefulness of medical checkups. The following were investigated: the relationship between actual as well as recalled results of medical checkups in 1992 and the recollection of them after one year, the effects of examinations after medical checkups in 1992 on their recollection of the checkup results after one year, the effects of actual as well as recalled 1992 checkup results on the recollection of the results one month after informing the workers of the results of their medical checkups in 1993, assurance of correct recollection of the results, the relationship between the usefulness of medical checkups, explanation of abnormal findings and the percentage of correct answers to the results of medical checkups in 1993 one month after informing the workers of their results. It was found that the percentage of correct answers to the results after one year was significantly lower than that after one month in 1992. The rate decreased with the increase in the number of abnormal items in medical checkups. Moreover, the rate also decreased when the results were abnormal. Further examinations in addition to the medical checkups influenced their recollection somewhat after one year. The results that the workers still remembered in 1992 had a stronger effect on their recalling the results one month after informing them in 1993 than the actual results in 1992. The workers' confidence in their recollection of the results was untrustworthy in the same way as their recollection of the results, and they were not able to maintain the recollection of the correct results, although many of the workers realized the usefulness of the medical checkups. Our results suggest that explanation of abnormal medical findings in 1993 was effective because the percentage of partial concordance between actual and recalled results was much higher in the workers who received the explanation than in the workers who did not receive it. 相似文献
56.
M Hisada T Fujita H Naoki Y Itagaki H Irie M Miyashita T Nakajima 《Canadian Metallurgical Quarterly》1998,36(8):1115-1125
Facile structure determination of acylpolyamines, glutamatergic nerve blocker obtained from the venom of the Joro spider (Nephila clavata) was carried out with the use of micro-column LC/MS and high energy collision induced dissociation (CID) mass spectrometry. 6-hydroxyindole-3-acetyl was proposed previously as a putative partial structure, for the acyl moiety of hydroxyindole-type polyamines (NPTX-1 to -6). The NMR data obtained for NPTX-6, NPTX-687 and hydroxyindole-3-acetic acid which was released by acid hydrolysis of Nephila clavata crude venom extracts proved that the lipophilic head is the 4-hydroxyindole-3-acetic acid. Various hydroxyindole-3-acetyl polyamines were found in N. Clavata venom and characterized by mass spectrometry. As a result, type-E, a new class of generalized acylpolyamine structure was proposed in addition to the previously reported polyamine backbones type-A to -D. 相似文献
57.
58.
Trauger SA Go EP Shen Z Apon JV Compton BJ Bouvier ES Finn MG Siuzdak G 《Analytical chemistry》2004,76(15):4484-4489
Silylation chemistry on porous silicon provides for ultrahigh sensitivity and analyte specificity with desorption/ionization on silicon mass spectrometry (DIOS-MS) analysis. Here, we report that the silylation of oxidized porous silicon offers a DIOS platform that is resistant to air oxidation and acid/base hydrolysis. Furthermore, surface modification with appropriate hydrophobic silanes allows analytes to absorb to the surface via hydrophobic interactions for direct analyte extraction from complex matrixes containing salts and other nonvolatile interferences present in the sample matrix. This enables rapid cleanup by simply spotting the sample onto the modified DIOS target and removing the liquid phase containing the interferences. This approach is demonstrated in the analysis of protein digests and metabolites in biofluids, as well as for the characterizing of inhibitors from their enzyme complex. An unprecedented detection limit of 480 molecules (800 ymol) for des-Arg(9)-bradykinin is reported on a pentafluorophenyl-functionalized DIOS chip. 相似文献
59.
Xiujun Gong Kensuke Nakamura Hua Yu Kei Yura Nobuhiro Go 《IEEE transactions on information technology in biomedicine》2007,11(4):428-434
The emerging grid computing technologies enable bioinformatics scientists to conduct their researches in a virtual laboratory, in which they share public databases, computational tools as well as their analysis workflows. However, the development of grid applications is still a nightmare for general bioinformatics scientists, due to the lack of grid programming environments, standards and high-level services. Here, we present a system, which we named Bioinformatics: Ask Any Questions (BAAQ), to automate this development procedure as much as possible. BAAQ allows scientists to store and manage remote biological data and programs, to build analysis workflows that integrate these resources seamlessly, and to discover knowledge from available resources. This paper addresses two issues in building grid applications in bioinformatics: how to smoothly compose an analysis workflow using heterogeneous resources and how to efficiently discover and re-use available resources in the grid community. Correspondingly an intelligent grid programming environment and an active solution recommendation service are proposed. Finally, we present a case study applying BAAQ to a bioinformatics problem. 相似文献
60.
This study was conducted to evaluate the cytoprotective activity of roasted coffee residues (RCRs) extract on mouse embryonic
fibroblast (MEF) cells. RCRs originated from Colombia and Honduras are relatively nontoxic to cell growth and even stimulate
cell proliferation. Colombian RCRs showed most efficient protective effects on MEF cells against oxidative damage induced
by H2O2 compared among the extracts prepared under the same roasting time. The most significant radical scavenging activity was measured
in RCR with roasting time of 8.5 min. Phenolic and nonphenolic compounds in RCRs were chlorogenic acid, caffeine, caffeic
acid, nicotinic acid, trigonelline, and 5-(hydroxymethyl)furfuralolehyde. Effect of Colombian RCRs on apoptosis occurred by
oxidative damage was evaluated by morphological and flow cytometric analysis. Apoptotic cell accumulation was decreased by
cotreatment of MEF cells with Colombian RCRs. These results suggested that antioxidant potency of RCRs suppresses the cytotoxicity
which is induced by H2O2 and has a protective effect on MEF cell against oxidative stress. 相似文献