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151.
This paper describes a new and objective method for tackling the problem of defining a multidisciplinary research area for bibliometric analysis. The test field was cardiovascular biology. A three stage process was adopted in setting a boundary around this research field:
- Appropriate sections of a hierarchical subject classification scheme, Medical Subject Headings (MeSH), were developed into a “MeSH filter” through which papers indexed in MEDLINE were screened.
- A panel of cardiovascular experts reviewed the core set of classification terms, identifying irrelevant and missing areas, facilitating the development of a more sophisticated “filter”.
- The definition was validated using publication lists from research departments with a known interest in cardiovascular research.
152.
The emerging multi-layer functional model for network operations decomposes management functions into several layers:Service Management Layer, Network Management Layer, Element Management Layer, andElement Layer. To realize the full benefits of this functional distribution, a reference architecture for operations applications is needed. This architecture should enable flexible placement of functions in computing systems or nodes, enable hiding of the complexities of distribution from applications, and prescribe principles for the specification of application interfaces to facilitate application interoperability. This paper describes such a framework architecture. In this framework, applications are deployed in software units calledbuilding blocks, each of which is independently installed and administered. Building blocks interact via interfaces calledcontracts. A contract is an open interface that is specified according to some principles, such as adherence to standard communication paradigms, separation of engineering aspects from functional aspects, and support for previous interface versions. The infrastructure, called theDistributed Processing Environment (DPE), provides communication and security services that enable building blocks to interact via contracts. The DPE provides access and location transparency to applications. The paper presents details of this architecture framework and an example to illustrate specification of contracts for network management functions. 相似文献
153.
The thermodynamic cycle of a resonant, MEMS-based, micro heat engine is characterized. The micro heat engine is an external combustion engine made of a cavity encapsulated between two membranes. The cavity is filled with saturated liquid–vapor mixture working fluid. Heat is added to and rejected from the engine at a frequency corresponding to the resonant frequency of the engine. Both pressure–volume and temperature-entropy diagrams are used to investigate the thermodynamic cycle of the resonant micro heat engine. The results show that the working cycle is nearly rectangular in shape and consists of two constant temperature processes and two constant volume processes. We hypothesize that major sources of irreversibility in the engine are heat transfer over finite temperature differences during heat addition and rejection, heat transfer into and out of engine thermal mass, viscous losses due to liquid working fluid motion, and heat escape from the engine to the surroundings. The maximum pressure and volume changes measured inside the engine cavity are 45?Pa and 0.55?mm3, respectively. The results show that for a heat addition of 1?mJ, the engine operates over a very small temperature difference. The small operating temperature difference is mostly attributable to the large thermal storage of the engine structure, the membranes and the wicks. The measured second law efficiency of the micro heat engine is 16?%. 相似文献
154.
Roberto da Costa Quinino Linda Lee Ho Anderson Laécio Galindo Trindade 《The International Journal of Advanced Manufacturing Technology》2014,72(1-4):101-106
This paper presents an approach for improving the control limits of $ \overline{X} $ control charts when the parameters of the process are estimated and the control chart is in operation. In these conditions, the observed average run length (ARL) may be very different from the planned ARL since the parameter estimates may have a larger error. To minimize this problem, the data collected in effective control (phase 2) will be used to re-estimate the parameters with a precision greater than that obtained in phase 1. Thus, we defined a minimum sample size of observations of phase 2, which is constituted of a mixture of two normal distributions that should be used to re-estimate the process parameters. The proposal is illustrated with numerical example. 相似文献
155.
The transient voltage response of ZrO2 oxygen sensors was examined following step changes in gas composition. The experiments were performed on a laboratory flow reactor at 600° C. Composition changes between (a) 100% and (b) 1% O2 in N2 produced response curves whose symmetry varied between composition steps (a) from low-to-high oxygen and (b) from high-to-low oxygen. This difference is due to the logarithmic dependence of sensor voltage on oxygen partial pressure. Corresponding oxygen partial pressure-time curves, derived from experimental voltage via the Nernst equation, are symmetric with respect to the direction of composition changes. Abrupt transitions are found in voltage-time curves at 600° C following step changes of reactive gases; e.g. from O2/N2 mixtures to CO/N2, H2/N2 or D2/N2 mixtures. These voltage-steps represent transitions in stoichiometry of the surface boundary layer on the ZrO2 sensor. Delay times before the transition also reflect reaction stoichiometry. Response times with O2/CO, O2/H2 and O2/D2 follow trends predicted by the kinetic theory of gases. A limited number of experiments were performed to examine the relationships between sensor response and sensor catalytic activity. Poorer oxidation catalytic activity parallels slower response characteristics. 相似文献
156.
Electrical resistivity of Ni–Cr alloys containing 5.5, 11.3, 15.7, 16.8, 19.4, 22.0, 24.6, and 27.0 at % Cr has been measured as a function of the absolute temperatureT between 4 and 300 K. The sample with the Cr content of 22.0 at % exhibits a small minimum at about 10 K. No minimum has been observed in any other of the above samples, although an anomalousT dependence has been found in alloys containing 15.7, 16.8, and 19.4 at % Cr. The minimum has been discussed from the viewpoint of the Béal-Monod theory for the Kondo effect in concentrated systems and the mechanism by Greig and Rowlands based on aT-dependent decrease of the impurity electrical resistivity. It is concluded that the minimum in the Ni–Cr system is still a phenomenon which is not well understood at the present time. 相似文献
157.
The mapping of the human genome has reawakened interest in the topic of race and genetics, especially the use of genetic technology to examine racial differences in complex outcomes such as health and intelligence. Advances in genomic research challenge psychology to address the myriad conceptual, methodological, and analytical issues associated with research on genetics and race. In addition, the field needs to understand the numerous social, ethical, legal, clinical, and policy implications of research in this arena. Addressing these issues should not only benefit psychology but could also serve to guide such thought in other fields, including molecular biology. The purpose of this special issue is to begin a discussion of this issue of race and genetics within the field of psychology. Several scholars who work in the fields of genetics, race, or related areas were invited to write (or had previously submitted) articles sharing their perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
158.
Existing transformational leadership research has focused primarily on the behaviors of leaders and their effects on followers. The authors extended this research by examining the social networks of managers who exhibit transformational leadership behaviors. Their focus was on the network of relationships that managers develop and whether they hold key positions in the organization's informal social networks. In a field study using data from 39 managers and 130 nonmanagement employees of 6 organizations, the authors found that managers who score higher on transformational leadership tend to hold more central positions in organizational advice and influence networks. Furthermore, the direct reports of these leaders were also more central in informal organizational networks. These results illuminate one of the ways that managers who exhibit transformational leadership behaviors may exert influence in organizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
159.
Rotondi A. J.; Haas G. L.; Anderson C. M.; Newhill C. E.; Spring M. B.; Ganguli R.; Gardner W. B.; Rosenstock J. B. 《Canadian Metallurgical Quarterly》2005,50(4):325
Objective: To evaluate the feasibility of a telehealth psychoeducation intervention for persons with schizophrenia and their family members. Study Design: Randomized controlled trial. Participants: 30 persons with schizophrenia and 21 family members or other informal support persons. Interventions: Web-based psychoeducation program that provided online group therapy and education. Main Outcome Measures: Measures for persons with schizophrenia included perceived stress and perceived social support; for family members, they included disease-related distress and perceived social support. Results: At 3 months, participants with schizophrenia in the intervention group reported lower perceived stress (p = .04) and showed a trend for a higher perceived level of social support (p = .06). Conclusions: The findings demonstrate the feasibility and impact of providing telehealth-based psychosocial treatments, including online therapy groups, to persons with schizophrenia and their families. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
160.
Anderson John R.; Taatgen Niels A.; Byrne Michael D. 《Canadian Metallurgical Quarterly》2005,31(4):749
E. Hazeltine, D. Teague, and R. B. Ivry (see record 2002-02997-003) have presented data that have been interpreted as evidence against a central bottleneck. This article describes simulations of their Experiments 1 and 4 in the ACT-R cognitive architecture, which does possess a central bottleneck in production execution. The simulation model is capable of accounting for the emergence of near-perfect timesharing in Experiment 1 and the detailed data on the distribution of response times from Experiment 4. With practice, the central bottleneck in ACT-R will be reduced to a maximum of 50 ms (1 production cycle) and can often be much less, depending on timing of stages and variability in their times. The authors also show, with a mathematical analysis of E. Hazeltine et al.'s Experiment 2, that the expected dual costs for these kinds of highly practiced tasks will be small in many circumstances, often under 10 ms. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献