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进度控制和质量控制在施工中的作用与关系
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作者 王法政 石可嘉 《中国新技术新产品》 2009年第10期157-157,共1页
适度均衡的加快施工进度,可以在计划工期内得到合理的提前,可以保证施工质量。严格控制质量,可以避免返工,进度则会加快;反之则会因返工,造成工期延后,施工成本增加;投资与质量的关系是质量好要增加施工成本,但严格控制质量,可以避免返... 适度均衡的加快施工进度,可以在计划工期内得到合理的提前,可以保证施工质量。严格控制质量,可以避免返工,进度则会加快;反之则会因返工,造成工期延后,施工成本增加;投资与质量的关系是质量好要增加施工成本,但严格控制质量,可以避免返工,提高了承包商的施工效益,减少建设项目的经常性维护费用,延长工程使用年限,反而降低了投资成本,提高了建设单位的投资效益。 展开更多
关键词 工程建设项目 质量控制 施工技术 成全控制
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Safety control for powder compaction of initiating explosive device 被引量:2
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作者 刘丰林 《Journal of Chongqing University》 CAS 2006年第1期16-18,共3页
Powder compaction is one of the most crucial processes in initiating explosive device manufacturing. The quality of powder compaction may influence the performances of product directly. Traditional powder compaction m... Powder compaction is one of the most crucial processes in initiating explosive device manufacturing. The quality of powder compaction may influence the performances of product directly. Traditional powder compaction mainly makes use of manual gravitational spiral loading machine or lever loading machine. Potential accident by the strike in powder compaction of initiating explosive device could risk life, property and the environment. To prevent this risk, automatic control system and control strategy can be used to guarantee no strike in pressing process. The scope of this paper is to analyze and review the control strategy for powder compact and discuss the experimental results for the application of the proposed strategy. 展开更多
关键词 safety control powder compaction initiating explosive device
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SECURE GROUP COMMUNICATIONS FOR LARGE DYNAMIC MULTICAST GROUP
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作者 Liu Jing Zhou Mingtian (College of Computer Science and Engineering, UEST of China, Chengdu 610054) 《Journal of Electronics(China)》 2003年第4期265-273,共9页
As the major problem in multicast security, the group key management has been the focus of research But few results are satisfactory. In this paper, the problems of group key management and access control for large dy... As the major problem in multicast security, the group key management has been the focus of research But few results are satisfactory. In this paper, the problems of group key management and access control for large dynamic multicast group have been researched and a solution based on SubGroup Secure Controllers (SGSCs) is presented, which solves many problems in IOLUS system and WGL scheme. 展开更多
关键词 Multicast security Group communication Group key management Access control Secret key tree
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Fully Integrated Machine Control for Ultra Precision Machining
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《Journal of Mechanics Engineering and Automation》 2013年第8期465-472,共8页
To meet the demands for highly advanced components with ultra precise contour accuracy and optical surface quality arising in the fields of photonics and optics, automotive, medical applications and biotechnology, con... To meet the demands for highly advanced components with ultra precise contour accuracy and optical surface quality arising in the fields of photonics and optics, automotive, medical applications and biotechnology, consumer electronics and renewable energy, more advanced production machines and processes have to be developed. As the complexity of machine tools rises steadily, the automation of manufacture increases rapidly, processes become more integrated and cycle times have to be reduced significantly, challenges of engineering efficient machine tools with respect to these demands expand every day. Especially the manufacture of freeform geometries with non-continuous and asymmetric surfaces requires advanced diamond machining strategies involving highly dynamic axes movements with a high bandwidth and position accuracy. Ultra precision lathes additionally equipped with Slow Tool and Fast Tool systems can be regarded as state-of-the-art machines achieving the objectives of high quality optical components. The mechanical design of such ultra precision machine tools as well as the mechanical integration of additional highly dynamic axes are very well understood today. In contrast to that, neither advanced control strategies for ultra precision machining nor the control integration of additional Fast Tool systems have been sufficiently developed yet. Considering a complex machine setup as a mechatronic system, it becomes obvious that enhancements to further increase the achievable form accuracy and surface quality and at the same time decrease cycle times and error sensitivity can only be accomplished by innovative, integrated control systems. At the Fraunhofer Institute for Production Technology IPT a novel, fully integrated control approach has been developed to overcome the drawbacks of state-of-the-art machine controls for ultra precision processes. Current control systems are often realized as decentralized solutions consisting of various computational hardware components for setpoint generation, machine control, HMI (human machine interface), Slow Tool control and Fast Tool control. While implementing such a distributed control strategy, many disadvantages arise in terms of complex communication interfaces, discontinuous safety structures, synchronization of cycle times and the machining accuracy as a whole. The novel control approach has been developed as a fully integrated machine control including standard CNC (computer numerical control) and PLC (programmable logic controller) functionality, advanced setpoint generation methods, an extended HMI as well as an FPGA (field programmable gate array)-based controller for a voice coil driven Slow Tool and a piezo driven Fast Tool axis. As the new control system has been implemented as a fully integrated platform using digital communication via EtherCAT, a continuous safety strategy could be realized, the error sensitivity and EMC susceptibility could be significantly decreased and the overall process accuracy from setpoint generation over path interpolation to axes movements could be enhanced. The novel control at the same time offers additional possibilities of automation, process integration, online data acquisition and evaluation as well as error compensation methods. 展开更多
关键词 Ultra precision machining fully integrated control highly dynamic axes FPGA EtherCAT.
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On Total Domination Polynomials of Certain Graphs
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作者 S. Sanal H. E. Vatsalya 《Journal of Mathematics and System Science》 2016年第3期123-127,共5页
We have introduced the total domination polynomial for any simple non isolated graph G in [7] and is defined by Dt(G, x) = ∑in=yt(G) dr(G, i) x', where dr(G, i) is the cardinality of total dominating sets of... We have introduced the total domination polynomial for any simple non isolated graph G in [7] and is defined by Dt(G, x) = ∑in=yt(G) dr(G, i) x', where dr(G, i) is the cardinality of total dominating sets of G of size i, and yt(G) is the total domination number of G. In [7] We have obtained some properties of Dt(G, x) and its coefficients. Also, we have calculated the total domination polynomials of complete graph, complete bipartite graph, join of two graphs and a graph consisting of disjoint components. In this paper, we presented for any two isomorphic graphs the total domination polynomials are same, but the converse is not true. Also, we proved that for any n vertex transitive graph of order n and for any v ∈ V(G), dt(G, i) = 7 dt(V)(G, i), 1 〈 i 〈 n. And, for any k-regular graph of order n, dr(G, i) = (7), i 〉 n-k and d,(G, n-k) = (kn) - n. We have calculated the total domination polynomial of Petersen graph D,(P, x) = 10X4 + 72x5 + 140x6 + 110x7 + 45x8 + [ 0x9 + x10. Also, for any two vertices u and v of a k-regular graph Hwith N(u) ≠ N(v) and if Dr(G, x) = Dt( H, x ), then G is also a k-regular graph. 展开更多
关键词 total dominating set total domination number total domination polynomial
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An Empirical Study on the Relationship Between China's Maize Price and Maize Import and Export Trade
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作者 Jiahui HOU Junying WEI 《Agricultural Science & Technology》 CAS 2016年第9期2209-2211,共3页
Based on the time series of China’s maize trade and domestic maize price,the article analyzes the relationship between domestic maize price and China’s maize international trade by using empirical methods.The result... Based on the time series of China’s maize trade and domestic maize price,the article analyzes the relationship between domestic maize price and China’s maize international trade by using empirical methods.The results show that there is a connection between domestic maize prices and China's maize international trade,but the link is not very close.Domestic maize price is the cause of China’s maize international trade change,but its impact is very limited;China's maize international trade also can make some difference on the domestic maize price.Based on the results of research,the article brings three suggestion and expectation to adjust China’s maize international trade and the cost control reasonably in order to stabilize domestic maize price and maize yield,and to protect domestic grain security. 展开更多
关键词 Maize price Maize import and export trade Grain security
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