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排序方式: 共有1008条查询结果,搜索用时 640 毫秒
31.
Cullen RH Smarr CA Serrano-Baquero D McBride SE Beer JM Rogers WA 《Applied ergonomics》2012,43(6):1122-1130
The design of and training for complex systems requires in-depth understanding of task demands imposed on users. In this project, we used the knowledge engineering approach (Bowles et al., 2004) to assess the task of mowing in a citrus grove. Knowledge engineering is divided into four phases: (1) Establish goals. We defined specific goals based on the stakeholders involved. The main goal was to identify operator demands to support improvement of the system. (2) Create a working model of the system. We reviewed product literature, analyzed the system, and conducted expert interviews. (3) Extract knowledge. We interviewed tractor operators to understand their knowledge base. (4) Structure knowledge. We analyzed and organized operator knowledge to inform project goals. We categorized the information and developed diagrams to display the knowledge effectively. This project illustrates the benefits of knowledge engineering as a qualitative research method to inform technology design and training. 相似文献
32.
A global inventory of nitric oxide emissions from soils 总被引:15,自引:1,他引:15
Over 60 published papers reporting field measurements of emissions of nitric oxide (NO) from soil are reviewed, and over 100 annual estimates of NO emissions were made for various types of ecosystems, including agricultural fields. These data were stratified by biome and the mean of each stratum was multiplied by an estimate of the biome area. A few strata were identified as clearly having low NO emissions: montane forests, swamps and marshes, tundra, and temperate forests that are not heavily affected by N deposition. The largest emissions were observed in tropical savanna/woodland, chaparral, and cultivated agriculture, but variation in NO emissions within these strata was also large. Although the stratification scheme fails to partition this within-stratum variation, it does clearly identify these biomes as globally important sources of NO and as areas where more research is needed to investigate within-biome variation in NO emissions. It is too early to tell whether differences in NO emissions between temperate and tropical agriculture are significant, but it is clear that agriculture is an important source of NO and that management practices affect NO emissions. The best current estimate of the global soil source of NO is 21 Tg N yr-1. Adsorption of NOx onto plant canopy surfaces may reduce emissions to the atmosphere to as low as 13 Tg N yr-1, although the absorption effect is probably smaller than this. An error term for the global estimate is difficult to determine, but it is at least ±4 and perhaps as large at ±10 Tg N yr-1. Hence, only modest progress has been made in narrowing uncertainties in the estimate of the global soil source of NO, although some published lower estimates appear unlikely. This inventory reconfirms that the soil source of NO is similar in magnitude to fossil fuel emissions of NOx. Further narrowing of the uncertainty of the estimate of global soil NO emissions will require more sophisticated and carefully chosen stratification schemes to address variation within biomes based on soil fertility, soil texture, climate, and management and will require linking this type of inventory and stratification with mechanistic models. 相似文献
33.
Schultheiss Oliver C.; Pang Joyce S.; Torges Cynthia M.; Wirth Michelle M.; Treynor Wendy 《Canadian Metallurgical Quarterly》2005,5(1):41
Participants (N = 216) were administered a differential implicit learning task during which they were trained and tested on 3 maximally distinct 2nd-order visuomotor sequences, with sequence color serving as discriminative stimulus. During training, 1 sequence each was followed by an emotional face, a neutral face, and no face, using backward masking. Emotion (joy, surprise, anger), face gender, and exposure duration (12 ms, 209 ms) were varied between participants; implicit motives were assessed with a picture-story exercise. For power-motivated individuals, low-dominance facial expressions enhanced and high-dominance expressions impaired learning. For affiliation-motivated individuals, learning was impaired in the context of hostile faces. These findings did not depend on explicit learning of fixed sequences or on awareness of sequence-face contingencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
X-ray and electron interactions with matter were used as probes to characterize the structure and chemistry of zirconia-thoria-urania ceramics. The ceramics were prepared by coprecipitation of Zr, Th and U salts. In this study, transmission electron microscopy (TEM) techniques such as energy dispersive X-ray (EDX) analysis and electron energy loss spectroscopy (EELS) complement X-ray diffraction, extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectroscopy (XANES), techniques to reveal the phase structure and chemistry. The results from XRD and EDX show that these ceramics separate into a Zr-based phase and an actinide-based phase with low mutual affinity of Th and Zr, as well as partial solubility of U in Zr. The comparison of EELS spectra collected for the ceramics with spectra collected for UO2 and U3O8 reference materials also allow us to assess U oxidation state independently in the two separate phases. 相似文献
35.
Eric N. Hanson I.-Cheng Chen Roxana Dastur Kurt Engel Vijay Ramaswamy Wendy Tan Chun Xu 《The VLDB Journal The International Journal on Very Large Data Bases》1998,7(1):12-24
A software architecture is presented that allows client application programs to interact with a DBMS server in a flexible
and powerful way, using either direct, volatile messages, or messages sent via recoverable queues. Normal requests from clients
to the server and replies from the server to clients can be transmitted using direct or recoverable messages. In addition,
an application event notification mechanism is provided, whereby client applications running anywhere on the network can register
for events, and when those events are raised, the clients are notified. A novel parameter passing mechanism allows a set of
tuples to be included in an event notification. The event mechanism is particularly useful in an active DBMS, where events
can be raised by triggers to signal running application programs.
Received July 21, 1995 / Accepted May 30, 1996 相似文献
36.
Wendy M. K. Shaw 《History of Photography》2013,37(1):80-93
Photography reached the Ottoman Empire soon after its invention, at about the time that painting began to be practised there as part of a broader project of assimilating aspects of European culture. This was in marked contrast to the situation in Europe, where photography had to contend with visual traditions from which it adopted pictorial conventions and subject matter. Instead of supplanting existing traditions of realistic visual representation, photography in the Ottoman Empire served as a discrete source of inspiration. This paper examines how this inversion of European experience within the Ottoman Empire provides an alternative to dominant narratives of photographic history. If one of the salient characteristics of modernist movements in Western art is their ability to break with tradition, then the adoption of Western practices of representation by artists within the Ottoman Empire may be viewed as a radical modernist success. 相似文献
37.
Jun-young Kwak Pradeep Varakantham Rajiv Maheswaran Yu-Han Chang Milind Tambe Burcin Becerik-Gerber Wendy Wood 《Autonomous Agents and Multi-Agent Systems》2014,28(4):605-636
This paper presents transformative energy-saving schedule-leveraging agent (TESLA), an agent for optimizing energy usage in commercial buildings. TESLA’s key insight is that adding flexibility to event/meeting schedules can lead to significant energy savings. This paper provides four key contributions: (i) online scheduling algorithms, which are at the heart of TESLA, to solve a stochastic mixed integer linear program for energy-efficient scheduling of incrementally/dynamically arriving meetings and events; (ii) an algorithm to effectively identify key meetings that lead to significant energy savings by adjusting their flexibility; (iii) an extensive analysis on energy savings achieved by TESLA; and (iv) surveys of real users which indicate that TESLA’s assumptions of user flexibility hold in practice. TESLA was evaluated on data gathered from over 110,000 meetings held at nine campus buildings during an 8-month period in 2011–2012 at the University of Southern California and Singapore Management University. These results and analysis show that, compared to the current systems, TESLA can substantially reduce overall energy consumption. 相似文献
38.
Wendy S. Smith David A. Johnston Harrison J. Wensley Suzanne E. Holmes Sopsamorn U. Flavell David J. Flavell 《International journal of molecular sciences》2020,21(22)
Cholesterol seems to play a central role in the augmentation of saporin-based immunotoxin (IT) cytotoxicity by triterpenoid saponins. Endolysosomal escape has been proposed as one mechanism for the saponin-mediated enhancement of targeted toxins. We investigated the effects of lipid depletion followed by repletion on Saponinum album (SA)-induced endolysosomal escape of Alexa Fluor labelled saporin and the saporin-based immunotoxin OKT10-SAP, directed against CD38, in Daudi lymphoma cells. Lipid deprived cells showed reduced SA-induced endolysosomal escape at two concentrations of SA, as determined by a flow cytometric method. The repletion of membrane cholesterol by low density lipoprotein (LDL) restored SA-induced endolysosomal escape at a concentration of 5 µg/mL SA but not at 1 µg/mL SA. When LDL was used to restore the cholesterol levels in lipid deprived cells, the SA augmentation of OKT10-SAP cytotoxicity was partially restored at 1 µg/mL SA and fully restored at 5 µg/mL SA. These results suggest that different mechanisms of action might be involved for the two different concentrations of SA and that endosomal escape may not be the main mechanism for the augmentation of saporin IT cytotoxicity by SA at the sub-lytic concentration of 1 µg/mL SA. 相似文献
39.
Alejandro M. Aragón Vladislav A. Yastrebov Jean‐François Molinari 《International journal for numerical methods in engineering》2013,96(5):323-338
The detection phase in computational contact mechanics can be subdivided into a global search and a local detection. When potential contact is detected by the former, a rigorous local detection determines which surface elements come or may come in contact in the current increment. We first introduce a rigorous definition of the closest point for non‐differentiable lower‐dimensional manifolds. We then simplify the detection by formulating an optimization problem subject to inequality constraints. The formulation is then solved using different techniques from the field of mathematical optimization, for both linear and quadratic finite element meshes. The resulting general and robust detection scheme is tested on a set of problems and compared with other techniques commonly used in computational geometry. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
40.
Niccols Alison; Milligan Karen; Sword Wendy; Thabane Lehana; Henderson Joanna; Smith Ainsley; Liu Jennifer; Jack Susan 《Canadian Metallurgical Quarterly》2010,24(3):466
To examine the impact of integrated treatment programs (those with substance use treatment and pregnancy-, parenting-, or child-related services) on maternal mental health, we compiled a database of studies of integrated programs published between 1990 and 2007 with outcome data on maternal mental health. There were 18 cohort studies, 3 randomized trials, and 2 quasi-experimental studies. Of the five studies comparing integrated to nonintegrated programs, three studies provided enough information to allow for them to be combined in a meta-analysis. The average effect size was 0.23 (95% CI = 0.15 to 0.31, SE = 0.04), p Q = 5.66, p = .059. This meta-analysis is the first systematic quantitative review of studies evaluating the impact of integrated programs on maternal mental health. Findings suggest that integrated programs may be associated with a small advantage over nonintegrated programs in improving maternal mental health. This review highlights the need for further research with improved methodology, study quality, and reporting to improve our understanding of how best to meet the mental health needs of mothers with substance abuse issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献