Martin M. Cummings, M.D.: a remarkable man retires with a truly remarkable legacy     

W D Mayer 《Bulletin of the Medical Library Association》1984,72(1):35-36

  相似文献   

Student development in junior high school science     

John F. Disinger  Victor I. Mayer 《科学教学研究杂志》1974,11(2):149-155

  相似文献   

Mobile Agents for Distributed and Heterogeneous Information Retrieval   总被引：1，自引：0，他引：1  

Subrata?DasEmail author  Kurt?Shuster  Curt?Wu  Igor?Levit 《Information Retrieval》2005,8(3):383-416

The heterogeneous, distributed and voluminous nature of many government and corporate data sources impose severe constraints on meeting the diverse requirements of users who analyze the data. Additionally, communication bandwidth limitations, time constraints, and multiple data formats impose further restrictions on users of these distributed data sources. In this paper, we present an Agent-based Complex QUerying and Information Retrieval Engine (ACQUIRE) for large, heterogeneous, and distributed data sources. ACQUIRE acts as a softbot or interface agent by presenting users with a view of a single, unified, homogenous data source, against which users can pose high-level declarative queries. ACQUIRE translates each such user query into a set of sub-queries by employing a combination of planning and traditional database query optimization techniques. ACQUIRE then spawns a set of mobile agents corresponding to these sub-queries, which in turn retrieve the data from various distributed data sources by dynamically optimizing the retrieval strategy as it is carried out. These mobile agents carry with them data-processing code that can be executed at the remote site, thus reducing the size of data returned by the agent. When all mobile agents have returned, ACQUIRE filters and merges the retrieved data and presents the results to the user. While the system is still very much a work in progress, current validation experiments on simulated NASA Distributed Active Archive Centers (DAACs) have demonstrated that complex queries can be effectively decomposed and retrieved by this approach.  相似文献   

Dynamic harmonic balance principle and analysis of rocking block motions     

Igor M. Boiko 《Journal of The Franklin Institute》2012,349(3):1198-1212

The harmonic balance (HB) principle is a powerful and convenient tool for finding periodic solutions in nonlinear systems. In the present paper, this principle is extended to transient processes in systems with one single-valued odd-symmetric nonlinearity and linear plant not having zeros in the transfer function, and named the dynamic HB. Based on the dynamic HB, first the equations for the amplitude, frequency, and amplitude decay of an oscillatory process in the Lure system are derived. It is then applied to analysis of rocking block decaying motions. An example is provided.  相似文献   

Stabilization of artificial gas-lift process using nonlinear predictive generalized minimum variance control     

Jing Shi  Ahmed Al-Durra  Rachid Errouissi  Igor Boiko 《Journal of The Franklin Institute》2019,356(4):2031-2059

Artificial gas-lift (AGL) is one of the most widely used methods in oil production to maintain acceptable oil flow to the processing equipment and sales when the reservoir pressure is not high enough. In spite of its popularity, the AGL process is prone to casing-heading instability, which is revealed as significant flow oscillation. This is undesirable as it results in production losses and unstable behavior that has negative impact on the downstream equipment. Controller design for such a process is very challenging as it exhibits highly nonlinear dynamics. In this work, the predictive generalized minimum variance control (NPGMV) is employed to derive a robust controller based on the state estimation to stabilize AGL process when casing-heading phenomenon occurs. A closed-form optimal control law is obtained based on the Taylor series approximation. Further, a nonlinear state observer is produced and combined with the controller to ensure closed-loop control through variables that are most beneficial to the system performance, which are unmeasurable and can be obtained only via estimation. Through simulation studies, the effectiveness of the proposed controller is demonstrated.  相似文献   

Influence of Process Parameters on Chlorinated Biocide Decontamination by li-CO2 on Artificially Contaminated Model Materials     

Tiziana Lombardo  Marie Wörle  Vera Hubert  Erwin Hildbrand  Christina Hinterleitner  Ingo Mayer 《文物保护研究》2020,65(2):65-76

ABSTRACT

Previously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO₂ was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO₂ decontamination include a single 30?min cycle for woolen materials and three sequential 30?min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present.  相似文献   

四月的诗     

叶子 《语数外学习(初中版)》2008,(4):1-1

晨月圆圆,金光灿烂,悬挂在雾霭蓝天上;高耸白杨独自摇晃,鸟鸣声声起伏不断,四月的第一天,朋友!在这愚人的四月,月亮闪着金光,如小巧温柔的太阳。The morning moon is round and goldUp in the misty milk-blue sky;The towering poplar sways alone;The birds are shouting one  相似文献   

A New Solution to the Paradoxes of Rational Acceptability   总被引：4，自引：0，他引：4  

Douven  Igor 《The British journal for the philosophy of science》2002,53(3):391-410

  相似文献   

Effects on response time and accuracy of technology-enhanced cloze tests: an eye-tracking study     

Ponce  Héctor R.  Mayer  Richard E.  Sitthiworachart  Jirarat  López  Mario J. 《Educational technology research and development : ETR & D》2020,68(5):2033-2053

Educational technology research and development - The transition from paper-based tests to corresponding computer-administered tests allows for the incorporation of improved interfaces that support...  相似文献   

Turn vs. shape: teachers cope with incompatible perspectives on angle     

Igor’ Kontorovich  Rina Zazkis 《Educational Studies in Mathematics》2016,93(2):223-243

  相似文献