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41.
John A. Hughes Dave Randall Dan Shapiro 《Computer Supported Cooperative Work (CSCW)》1992,1(3):123-141
This paper explores the issues involved in moving from ethnographic explorations of work in context to a practical contribution to system design. It does so using the example of an interdisciplinary research project involving sociologists and computer scientists in the domain of air traffic control systems. It forms a pair with another paper (Sommerville et al., 1992) exploring these questions from the perspective of our computer science partners. We characterise ethnography as a research method, and consider the differences between undertaking it for strictly sociological or anthropological purposes by contrast with interdisciplinary and design purposes. We summarise some of our results in ethnographic explications of the work of air traffic controllers, and the sociality which it manifests. We describe the dialogues involved in rendering these observations informative for systems design, and the mutual translations implied in attempting to reconcile sociological with software engineering questions about supporting the work. We conclude by specifying some features of cooperative work which an engineering approach is in danger of overlooking; the ways, and limits, in which ethnographers can form a bridge between users and designers; and some of the conflicts of interest entrained in generating technical change.The research is funded by the UK MRC/SERC/ESRC Cognitive Science/HCI Initiative with the title Social Analysis of Control Systems for HCI Design, grant number SPG 8931598. The computer science partners are Professor Ian Sommerville, Dr Tom Rodden, Dr Pete Sawyer and Mr Richard Bentley. Thanks are due to Val King, Kjeldt Schmidt, Ian Sommerville and Tom Rodden for very helpful comments on earlier drafts of this paper. 相似文献
42.
43.
(反应)模晶生长法制备NBT-6BT织构陶瓷的研究 总被引:1,自引:0,他引:1
以熔盐法合成的片状SrTiO3,Bi4Ti3O12为种晶,分别采用模晶生长法(TGG)和反应模晶生长发(RTGG)制备了具有〈001〉取向的0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3(NBT-6BT)织构陶瓷。研究了不同种晶选择、流延和热处理工艺参数对陶瓷织构化程度、显微结构和压电性能的影响。结果表明,RTGG制备的织构陶瓷比TGG的在结构和性能等方面都具有优势,且用该方法以Bi4Ti3O12为种晶,制备出了高密度(f≥96%)、高织构度(F≈95%)、高性能(d33≈241pC/N)的NBT-6BT无铅压电陶瓷。 相似文献
44.
Gang Li Dan I. Enache Jennifer Edwards Albert F. Carley David W. Knight Graham J. Hutchings 《Catalysis Letters》2006,110(1-2):7-13
The oxidation of benzyl alcohol to benzaldehyde has been investigated in the absence of solvent using zeolite-supported Au
and Au–Pd catalysts. Three zeolites were investigated, ZSM-5, zeolite β and zeolite Y, and these were contrasted with the
titanoslicalite TS-1 and TiO2 as supports. For the Au catalysts the best results are obtained with zeolite β as the support and the conversions were comparable
or better than those observed with TiO2 in terms of turn over frequencies. However, the selectivities observed with the acidic zeolites were lower than the non-acidic
TS-1 and TiO2. This is due to the subsequent reaction of benzaldehyde via acid catalysed reactions to give benzyl benzoate and its dibenzyl
acetal, and, in some cases dibenzylether. Initial catalysts were evaluated with a gold loading of 2 wt% and increasing this
to 4 wt% showed the expected increase in activity, indicating that there is scope to improve the performance of these catalysts.
The most active catalysts were prepared by impregnation and catalysts prepared by deposition precipitation were considerably
less active. Introduction of Pd into the catalyst improved the activity without significantly affecting the selectivity. 相似文献
45.
46.
In manufacturing industries, the quality of a product depends on the combined effect of multiple input variables working singly or together and therefore attention has been given on process capability indices to shift from single to multivariate domain. In case of multivariable domain the capability to incorporate uncertainties at the time of decision making becomes necessary. Fuzzy system is introduced to take care of this requirement. In this article the process parameters of soap manufacturing industries have been analyzed. The process capability is determined using Fuzzy Inference System rule editor based on a set of justified if then statements as applicable for the process. The data has been collected in linguistic form to derive its process capability, using a set of justified rules and the effect of each factor has been determined using Design of Experiments (DoE) and analysis of variance technique (ANOVA) for improving the soap quality from perspective of its softness. This article ventures to propose a new methodology by integrating Fuzzy with DoE providing better result followed by DoE and Fuzzy Inference system in isolation. 相似文献
47.
Recent progress in road and lane detection: a survey 总被引:2,自引:0,他引:2
The problem of road or lane perception is a crucial enabler for advanced driver assistance systems. As such, it has been an active field of research for the past two decades with considerable progress made in the past few years. The problem was confronted under various scenarios, with different task definitions, leading to usage of diverse sensing modalities and approaches. In this paper we survey the approaches and the algorithmic techniques devised for the various modalities over the last 5 years. We present a generic break down of the problem into its functional building blocks and elaborate the wide range of proposed methods within this scheme. For each functional block, we describe the possible implementations suggested and analyze their underlying assumptions. While impressive advancements were demonstrated at limited scenarios, inspection into the needs of next generation systems reveals significant gaps. We identify these gaps and suggest research directions that may bridge them. 相似文献
48.
耐药大肠杆菌的致病性与免疫原性 总被引:1,自引:0,他引:1
目的了解大肠杆菌耐药株的致病性与免疫原性。方法临床分离耐药大肠杆菌,经适宜条件培养后接种小鼠,观察耐药菌株对小鼠的致病性;并选择已知血清型的不同耐药谱和不同耐药水平的菌,分别培养至对数生长期,经甲醛灭活后免疫小鼠,2周后分别用致死剂量的原菌株和同期分离菌株进行攻毒,考察耐药菌株免疫原性。结果24株耐药菌普通肉汤培养物分别感染小鼠,在接种后18h,存活率仅为4%。只有2株菌在1周内仍不能将小鼠全部致死,经小鼠体内传3代后,可在18h内致死小鼠。耐药谱广的菌株感染的小鼠,心肌发生颗粒变性、局灶性出血、坏死;肝脏糖元溶解,脂肪变性;脾脏轻度淤血,淋巴细胞减少;肾脏出血,肾小球肾炎,上皮细胞颗粒变性,水泡变性。而耐药种类少的菌株与对照敏感菌株感染的小鼠主要特征为脾脏出血、淤血,坏死,脾小体消失;肠上皮细胞坏死、脱落、卡他性肠炎。免疫小鼠以免疫用菌株攻毒,均可得较高的保护率,最低为75%,最高为100%。免疫小鼠用非免疫菌株攻毒,小鼠感染后症状出现较缓慢,在18h后出现死亡高峰。耐药种类少的菌株免疫小鼠,对同期分离的非免疫用的致病性大肠杆菌攻击的保护率偏低,而对受试的11种抗生素耐受7种以上的菌株免疫小鼠后,对致病大肠杆菌攻击的保护率显著提高,多数达到75%以上,经统计学分析差异显著。结论耐药大肠杆菌具有较强致病性,且耐药特性与其免疫保护效果相关,多重耐药株对当前流行菌株具有更好的免疫保护作用。 相似文献
49.
This paper presents a data-driven modeling and optimization method for cavity filters, according to a limited amount of measurement data. In the method, a model that reveals the effect of mechanical structure on electrical performance of cavity filters is firstly developed by an improved algorithm, which can increase the modeling accuracy of small data set by incorporating multi-kernel and prior knowledge into the framework of linear programming support vector regression. Then, an approach to optimize the structure of cavity filters is formulated by using the developed data-based model, and the obtained results can assist the fabrication of the same filter in the future. Some experiments from a synthetic example and a practical application of cavity filter have been carried out, and the experimental results confirm the effectiveness of the method. The model is particularly suited to a computer-aided manufacturing of volume-producing filters, and the proposed algorithm shows great potential in some applications where the experimental data are very few and the prior knowledge is available. 相似文献
50.
The existing solutions to keyword search in the cloud can be divided into two categories: searching on exact keywords and searching on error-tolerant keywords. An error-tolerant keyword search scheme permits to make searches on encrypted data with only an approximation of some keyword. The scheme is suitable to the case where users' searching input might not exactly match those pre-set keywords. In this paper, we first present a general framework for searching on error-tolerant keywords. Then we propose a concrete scheme, based on a fuzzy extractor, which is proved secure against an adaptive adversary under well-defined security definition. The scheme is suitable for all similarity metrics including Hamming distance, edit distance, and set difference. It does not require the user to construct or store anything in advance, other than the key used to calculate the trapdoor of keywords and the key to encrypt data documents. Thus, our scheme tremendously eases the users' burden. What is more, our scheme is able to transform the servers' searching for error-tolerant keywords on ciphertexts to the searching for exact keywords on plaintexts. The server can use any existing approaches of exact keywords search to search plaintexts on an index table. 相似文献