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991.
992.
During the period 1952 to 1965, there were strenuous world-wide efforts to produce an automated cotton spinning mill. These attempts, which involved the use of concepts developed outside the textile machinery industry (i.e. automatic transfer systems), were motivated by the need to reduce the very great amount of manual handling of packages between successive operations in the yarn manufacturing process.The case is unusual in that, while many of the developments were ‘technically successful’ in that installations were made which functioned satisfactorily in the mill), they were, without exception, commercially unsuccessful from the point of view of the machinery manufacturer and mill operator. This paper describes the economic forces which led to the attempts at automation, and explains why, after an expenditure in excess of £ 25 mill/on worldwide, commercial success was not achieved.The prime reason for failure lay in minor and major developments of existing individual machines, which had continued independently of automation research, and which had, to a great extent, obviated the economic need for automation. The surprising thing (in retrospect at least), is that, as production rates were increased step by step, development engineers working to produce automated systems saw, in the increasing speeds, only a challenge to their ingenuity — not a disappearance of the need for automatic transfer devices.A secondary reason for failure in the particular case of the Shirley Institute's automated card room sequence lay in the fact that the research was directed by a committee whose terms of reference were limited to pursuance of a defined goal — the development of an automated card room. The committee had no mandate to question the soundness of its objectives, and the work continued until a technically successful system was finally produced. 相似文献
993.
This paper deals with the experimental aspects of ultrasonic delay lines in liquid media and is a sequel to a previous paper treating the general theory of such devices.Delay devices employing ultrasonic propagation through liquids have proved satisfactory for delay times of the order of 3 milliseconds or less. Such devices can be made broadband and give excellent reproduction of pulse shape. The design considerations for such devices are discussed and illustrated by actual examples. 相似文献
994.
The structure of a retrospective information retrieval system that uses equifrequent word or text fragments is described, and its advantages over word oriented systems are mentioned briefly. Word fragments are proposed as retrieval elements, and a discussion is given of the changes required in order to process a query. Some necessary modifications in the treatment of logical operators are described, and two conditions are postulated as necessary for the successful operation of the system. Aspects of query processing are illustrated by experimental results obtained from single and two-term queries applied to a portion of the MARC tapes. 相似文献
995.
For some 300 years the modelling of uncertainty in the sciences has been totally dominated by probabilistic methods. Now, following major criticism of the theoretical foundations of probability theory, other approaches to dealing with uncertainty are being explored. 相似文献
996.
Susan H. Landry Paul R. Swank Jason L. Anthony Michael A. Assel 《Reading and writing》2011,24(8):971-1010
This paper describes the implementation and evaluation for scaling up a comprehensive early childhood teacher professional development program into 11 communities across 2 years with funding through state legislative actions. The comprehensive program had four major components based on results from a previous multi-condition random assignment study across four states. The previous results demonstrated that the most optimum approach for supporting children??s school readiness included: (1) teacher on-line professional development with facilitation, (2) classroom mentoring, (3) implementation of a research-based curriculum, and (4) technology-driven progress monitoring that informed instruction. The comprehensive professional development program was evaluated in a new state program designed to bring childcare, Head Start, and public school pre-kindergarten together into integrated partnerships. In Year 1, 220 teachers serving 3834 children were randomly assigned to either receive the comprehensive program or not. Teachers who served as controls in Year 1 received the program in Year 2, and those who received the program in Year 1 participated for an additional year in Year 2, allowing for examination of the effects of one versus 2 years of participation. The program improved teachers instructional practices relative to controls, and a second year of participation resulted in greater gains in children??s language and literacy. Results support the need for well-integrated, comprehensive professional development for early childhood educators. 相似文献
997.
Teaching and learning with history and philosophy of science (HPS) has been, and continues to be, supported by science educators. While science education standards documents in many countries also stress the importance of teaching and learning with HPS, the approach still suffers from ineffective implementation in school science teaching. In order to better understand this problem, an analysis of the obstacles of implementing HPS into classrooms was undertaken. The obstacles taken into account were structured in four groups: 1. culture of teaching physics, 2. teachers?? skills, epistemological and didactical attitudes and beliefs, 3. institutional framework of science teaching, and 4. textbooks as fundamental didactical support. Implications for more effective implementation of HPS are presented, taking the social nature of educational systems into account. 相似文献
998.
Webb SJ Jones EJ Merkle K Venema K Greenson J Murias M Dawson G 《Child development》2011,82(6):1868-1886
Individuals with autism spectrum disorder (ASD) show differences in face processing abilities from early in development. To examine whether these differences reflect an atypical versus delayed developmental trajectory, neural responses to familiar and unfamiliar faces in twenty-four 18- to 47-month-old children with ASD were compared with responses of thirty-two 12- to 30-month-old typically developing children. Results of 2 experiments revealed that neural responses to faces in children with ASD resembled those observed in younger typically developing children, suggesting delayed development. Electrophysiological responses to faces were also related to parent report of adaptive social behaviors for both children with ASD and typical development. Slower development of the face processing system in ASD may be related to reduced self-directed "expected" experience with faces in early development. 相似文献
999.
The current study was designed to investigate how the quality of stimulation and support available to children in the home interacts with participation in Early Head Start to determine children's development. Data were obtained as part of the national evaluation of Early Head Start (EHSRE), a randomized trial involving 3,001 children and families from 17 program sites. Hierarchical linear regression analyses were used to examine the interaction of EHS with (a) early maternal emotional warmth and (b) provision of a stimulating home environment on children's development at ages 3 and 5. Findings showed EHS sometimes differentially benefited children who came from households where the levels of warmth and stimulation were lowest. However, there was evidence of other forms of moderation as well. 相似文献
1000.
This study used eye-tracking methodology to assess audiovisual speech perception in 26 children ranging in age from 5 to 15 years, half with autism spectrum disorders (ASD) and half with typical development. Given the characteristic reduction in gaze to the faces of others in children with ASD, it was hypothesized that they would show reduced influence of visual information on heard speech. Responses were compared on a set of auditory, visual, and audiovisual speech perception tasks. Even when fixated on the face of the speaker, children with ASD were less visually influenced than typical development controls. This indicates fundamental differences in the processing of audiovisual speech in children with ASD, which may contribute to their language and communication impairments. 相似文献