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101.
Business, not technology leaders should manage the change of Information Technology (IT) from a self-contained business support unit of the sixties to a distributed strategic business function of the nineties. Top management should recognize that a good business plan can only be developed and executed through the partnership between the business unit managers and the managers of the financial, the personnel, and the IT resource units. The technical problems associated with the management of IT may again be the easier part of the total management challenge. 相似文献
102.
David Mills 《Granular Matter》2004,6(2-3):173-177
For fine powdered materials, capable of being conveyed in dense phase, a conveying region exists in which instability in flow and pipeline blockage can occur if the pressure gradient available is insufficient to maintain a minimum value of solids loading ratio. A reduction in material flow rate can also lead to pipeline blockage in this region. Conveying trials under-taken with cement are used to illustrate the nature of the problem. 相似文献
103.
A semi-empirical mathematical model for the acid-oxygen pressure leaching of Ni–Cu matte is presented, based on data from batch leaching experiments. The primary controlling factor in the leaching process is found to be galvanic inhibition of the more highly oxidized copper and nickel sulfide species by less oxidized species, particularly Ni alloy and Ni3S2. The leaching rate of many species is greatly reduced by the presence of one or both of these phases, and others will not commence leaching until neither is present. The mathematical model is based on first-order chemical reaction controlled rate expressions, as the reactions occurring are electrochemical in nature. Mass transfer effects are included only empirically. Some possibly diffusion-related phenomena are noted, although the model is not extended to incorporate these effects on a fundamental level. The model is verified and extended by the inclusion of several different factors that were tested experimentally. The effects of variations in O2 flow rate and partial pressure, initial particle size, reaction pulp density and initial acid concentration were all studied, and included in the model. Variations in O2 flow rate and partial pressure are found to affect the reaction rates via the dissolved oxygen concentration in the solution phase. 相似文献
104.
105.
We present some new lower bounds on the optimal information rate and on the optimal average information rate of secret sharing schemes with homogeneous access structure. These bounds are found by using some covering constructions and a new parameter, the k-degree of a participant, that is introduced in this paper. Our bounds improve the previous ones in almost all cases. 相似文献
106.
107.
The State of the Art in Text Filtering 总被引:1,自引:0,他引:1
This paper develops a conceptual framework for text filtering practice and research, and reviews present practice in the field.
Text filtering is an information seeking process in which documents are selected from a dynamic text stream to satisfy a relatively
stable and specific information need. A model of the information seeking process is introduced and specialized to define text
filtering. The historical development of text filtering is then reviewed and case studies of recent work are used to highlight
important design characteristics of modern text filtering systems. User modeling techniques drawn from information retrieval,
recommender systems, machine learning and other fields are described. The paper concludes with observations on the present
state of the art and implications for future research on text filtering.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
108.
A. B. Ngowi 《Building Research & Information》1998,26(6):340-350
Has specialization of professional roles obstructed the holistic approach and sustainable development? A preliminary survey in Botswana involving construction professionals found that existing procurement systems have not integrated the efforts of the different project participants and also fail to fulfil the expectations of the users. A holistic approach involving the re-integration of construction disciplines by applying new procurement methods is proposed. An integrated, holistic way of working could provide a number of synergies through the consideration of the building project as an entire system. The implications include better decision making upstream, more efficient use of resources and the mitigation of negative environmental effects downstream.
La specialisation professionnelle est-elle un obstacle a l'approche globale et au developpement durable? Une etude preliminaire menee au Botswana et portant sur les metiers de la construction a revele que les systemes d'approvisionnement actuels n'integrent pas les efforts des differents participants a un projet et ne repondent pas aux attentes des utilisateurs. Cet article propose une approche globale dont le succes repose sur la reintegration de ces metiers et sur de nouvelles methodes d'approvisionnement. Une methode de travail integree et holistique, ou un projet de construction serait considere comme un systeme complet, pourrait faire naitre un certain nombre de synergies. Cette hypothese exige un meilleur processus decisionnel en amont une utilisation plus efficace des ressources et l'attenuation des effets negatifs sur l'environnement en aval. 相似文献
La specialisation professionnelle est-elle un obstacle a l'approche globale et au developpement durable? Une etude preliminaire menee au Botswana et portant sur les metiers de la construction a revele que les systemes d'approvisionnement actuels n'integrent pas les efforts des differents participants a un projet et ne repondent pas aux attentes des utilisateurs. Cet article propose une approche globale dont le succes repose sur la reintegration de ces metiers et sur de nouvelles methodes d'approvisionnement. Une methode de travail integree et holistique, ou un projet de construction serait considere comme un systeme complet, pourrait faire naitre un certain nombre de synergies. Cette hypothese exige un meilleur processus decisionnel en amont une utilisation plus efficace des ressources et l'attenuation des effets negatifs sur l'environnement en aval. 相似文献
109.
本文介绍了全球N-ISDN的商用情况和B-ISDN的发展趋势,展示出N-ISDN走了低谷、B-ISDN迈向市场的美好前景。 相似文献
110.
集成光学干涉仪光纤陀螺 总被引:2,自引:0,他引:2
简述了集成光学干涉仪光纤陀螺(FOG)的技术优势、发展概况和采用的技术途径,介绍了适用于不同技术条件要求的三种多功能集成光学芯片结构和相应的信息处理方法。简要地概括了目前国外FOG的发展水平。 相似文献