共查询到20条相似文献，搜索用时 736 毫秒
1.
《Journal of The Franklin Institute》2007,344(3-4):243-256
A new pre-processing method for colour fundus images with adaptive contribution of the red channel is proposed. Based on a condition that is developed in this paper, this method utilises the intensity information from both red and green channels instead of using only the green channel as in the usual practice. The histogram matching is used to modify the histogram of the green channel by using the histogram of the red channel (of the same retinal image) to obtain a new processed image having the advantages of both channels. This method can be used to correct non-uniform illumination in colour fundus images or as a pre-processing step in the automatic analysis of retinal images.Results show that the use of histogram matched (HM) image give better performance than using the green channel image when employing the two-dimensional matched filter to detect retinal blood vessels. At specificity of 90%, in case of abnormal images, sensitivity increased from 76% when using the green channel image to 82% when using the HM image compared with 81% when using the piece-wise threshold probing method. In case of normal images, at the same specificity, the sensitivity obtained when using green channel image or HM image was 87% compared with 88% for the piece-wise threshold probing method. 相似文献
2.
This study uses bibliometric analysis and citation context analysis to identify the influence of the main concepts embedded in Taylor’s 1968 classic article entitled Question-Negotiation and Information-Seeking in Libraries. This study analyses articles published between 1969 and 2010 which cite Taylor’s article. The results show that Taylor’s article on a question-negotiation model is increasingly visible and its influence is not limited to the discipline of library and information science. Of the 14 cited concepts identified, the concept of “four levels of information needs” was cited most (31.7%), followed by “question negotiation” (20.5%) and “other concepts relating to information needs” (17.9%). The results indicate an increasing trend in the citations of “four levels of information needs” and this concept also received the most attention from information retrieval research. A decreasing trend was evident for the concept of “question negotiation” and this concept was frequently cited by reference service researchers. In addition, among the 10 citation functions, “related literature” was dominant (30.8%). Both “evidence” and “views” were in second place with the same percentage (18.7%), followed by “terms” (9.2%) and “background information” (7.2%). A decreasing trend was identified in the top three citation functions, whereas an increasing trend was observed in the “term” and “background information” functions. 相似文献
3.
In image retrieval, most systems lack user-centred evaluation since they are assessed by some chosen ground truth dataset. The results reported through precision and recall assessed against the ground truth are thought of as being an acceptable surrogate for the judgment of real users. Much current research focuses on automatically assigning keywords to images for enhancing retrieval effectiveness. However, evaluation methods are usually based on system-level assessment, e.g. classification accuracy based on some chosen ground truth dataset. In this paper, we present a qualitative evaluation methodology for automatic image indexing systems. The automatic indexing task is formulated as one of image annotation, or automatic metadata generation for images. The evaluation is composed of two individual methods. First, the automatic indexing annotation results are assessed by human subjects. Second, the subjects are asked to annotate some chosen images as the test set whose annotations are used as ground truth. Then, the system is tested by the test set whose annotation results are judged against the ground truth. Only one of these methods is reported for most systems on which user-centred evaluation are conducted. We believe that both methods need to be considered for full evaluation. We also provide an example evaluation of our system based on this methodology. According to this study, our proposed evaluation methodology is able to provide deeper understanding of the system’s performance. 相似文献
4.
A user study of aNobii was conducted with an aim to exploring possible criteria for evaluating social navigational tools. A set of measures designed to capture various aspects of the benefits provided by the tools was proposed. To test the applicability of these measures, a within-subject experimental design was adopted where fifty regular aNobii users searched alternately with three book-finding tools: browsing “friends’ bookshelves”, “similar bookshelves”, and “books by known authors”. Other than the self-report user experience and search result measures, the “choice set” model was used as a novel framework for navigational effectiveness. Further analyses were conducted to explore whether three aspects of reader preference, “preference insight”, “preference diversity”, and “reading involvement” might influence the performance of the tools. 相似文献
5.
A well-known challenge for multi-document summarization (MDS) is that a single best or “gold standard” summary does not exist, i.e. it is often difficult to secure a consensus among reference summaries written by different authors. It therefore motivates us to study what the “important information” is in multiple input documents that will guide different authors in writing a summary. In this paper, we propose the notions of macro- and micro-level information. Macro-level information refers to the salient topics shared among different input documents, while micro-level information consists of different sentences that act as elaborating or provide complementary details for those salient topics. Experimental studies were conducted to examine the influence of macro- and micro-level information on summarization and its evaluation. Results showed that human subjects highly relied on macro-level information when writing a summary. The length allowed for summaries is the leading factor that affects the summary agreement. Meanwhile, our summarization evaluation approach based on the proposed macro- and micro-structure information also suggested that micro-level information offered complementary details for macro-level information. We believe that both levels of information form the “important information” which affects the modeling and evaluation of automatic summarization systems. 相似文献
6.
In view of the controversial policy debate on “green” growth and corresponding stimulus packages we empirically investigate the production effects of environmental investment as well as of environmental and energy expenditures. Using a panel dataset of German manufacturing sectors our econometric analysis identifies a positive impact of environmental investment on production growth. In contrast, our estimation results cannot support the hypothesis of positive production impacts induced by environmental or energy expenditures. We thus conclude that environmental regulation should in particular stimulate environmental investment in order to be compatible with the pursuit of production growth. 相似文献
7.
This paper focuses on the role of capabilities in economic development. In recent years, the quality and availability of data on different aspects of development have improved, and this provides new opportunities for investigating the reasons behind the large differences in economic development. Using factor analysis on data for 25 indicators and 115 countries between 1992 and 2004, we identify four different types of “capabilities”: the development of the “innovation system”, the quality of “governance”, the character of the “political system” and the degree of “openness” of the economy. Innovation systems and governance are shown to be of particular importance for economic development. 相似文献
8.
This study examines how libraries within college and university settings in the United States have dealt with the influx of patron mobile telephone use. We contacted 150 colleges and universities throughout the United States and received 87 responses. These institutions were ranked by US News and World Report in their 2006 Edition of “America’s Best Colleges;” we sampled from their list stratified within the following categories: “top public universities;” “best liberal arts colleges;” “fourth tier liberal arts colleges;” “best national universities;” and “fourth tier national universities.” We found that those college and university libraries adopt an array of stances when approaching cell phone use within their library facilities. These approaches include structured guidelines that specifically address cell phone use posted on the library website, signs displayed throughout the library barring cell phone use, and signage that provides patrons with a list of areas in which use is permitted. Interestingly, we found that several libraries lack any kind of mobile phone policy and instead, assume all patrons will behave in a proper way. 相似文献
9.
The second French Community Innovation Survey (CIS) indicates that 14% of R&D collaborating firms had to abandon or delay their innovation projects due to difficulties in their partnerships, an outcome which we term “cooperation failures”. Controlling for sample selection on the cooperation decision, our estimates show that firms collaborating with competitors and public research organizations (PROs), especially when they are foreign, are more likely to delay or stop an innovation project because of difficulties encountered in their R&D partnerships. More surprisingly, firms collaborating with their suppliers also face a higher risk of “cooperation failures”. At least for PROs, firms can reduce the risk of “cooperation failures” through previous experiences in partnerships. Larger firms and group subsidiaries are less likely to face “cooperation failures”, and so do firms in industries with a strong appropriability regime. 相似文献
10.
In the last several decades it has become an important basis to retrieve images from image databases (IDBs) by the semantic information held in the image objects and the spatial patterns formed by these objects. In this paper, we propose a new method for similarity retrieval of symbolic images by both the attributes and the spatial relationships of the contained objects. The proposed method CPM (common pattern method) retains the common spatial patterns of two images in new data structures CP_DAG (common pattern directed acyclic graph) and performs the similarity calculation efficiently in practice. The conducted experiments use both a synthetic dataset and an existing image database. The experimental results show that CPM outperforms LCS_Clique, SIMR, SIMDTC, and 2D Be-string for average efficiency and effectiveness. CPM also has steady efficiency while the number of image objects and the object symbol duplication rates increase. 相似文献
11.
In this paper, linkages of S&T activities between industry and science are statistically investigated, based on a firm level dataset from an S&T survey by the National Bureau of Statistics (NBS) of the PRC of about 22,000 manufacturing firms. During the transition period of China's innovation system from 1996 to 2002, firms’ S&T outsourcing activities increased significantly. Econometrics analysis reveals that (1) “absorptive capacity” for S&T outsourcing becomes important over time, (2) innovation system reforms for more market-based competition work for better incentive scheme for innovation though S&T linkage activities and (3) government funding of S&T induces more S&T linkages. 相似文献
12.
Do men and women academic faculty vary in their research collaboration patterns and strategies? This straightforward question does not lend itself to a straightforward answer. A great many sex-correlated variables could possibly mitigate the relationship of sex and collaboration. If one finds sex-correlated differences in the number of collaborators, can one infer that there is something intrinsic to men's and women's work strategies and preferences? Or would such differences owe instead to women's and men's different positions in work structures and hierarchies? The focus here is on two sets of research collaboration variables, numbers of collaborators and the collaboration strategies employed. The study uses questionnaire data from the U.S. National Survey of Academic Scientists (n = 1714) and tests several hypotheses about collaboration numbers and strategies. Regression results indicate, counter to the core hypotheses and almost all published literature, that in a properly specified model, one taking into account such factors as tenure, discipline, family status and doctoral cohort, women actually have somewhat more collaborators on average than do men. For both men and women, those with more industrial interactions and those affiliated with university research centers have more collaborators. Men and women differ in their collaborator choice strategies. Men are more likely to be oriented to “instrumental,” and “experience” strategies, while both men and women are motivated by “mentoring” strategies. Regression analyses show that for both men and women, having a coherent collaborator choice strategy predicts the number of collaborators. 相似文献
13.
Taleb H. Ibrahim 《Journal of The Franklin Institute》2010,347(5):875-881
Recently molecular modeling was employed on the metal-extracted aggregates that form during the liquid/liquid extraction of transition metals. During the extraction process, the aqueous phase pH is adjusted with sodium hydroxide. In additional to the formation of the transition metal-extractant reversed micelles, sodium-bis(2-ethylhexyl) phosphate (NaDEHP) reversed micelles can also form. According to the classical model of reversed micelles, water molecules act as promoters for the formation of reversed micelles. Water molecules act as “gluing” agents for micellization in apolar media. Here we report a unique finding about the role of water molecules in reversed micellar aggregates using molecular modeling. The molecular modeling of the reversed micellar system of NaDEHP in n-heptane clearly shows that water molecules can act as an “antimicellization” agent. Water molecules have no gluing effect on the formation of NaDEHP reversed micelles. In fact, large NaDEHP reversed micelles are formed in “dry” conditions. 相似文献
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15.
This paper reports the results of a study that examined Arabic-speaking children’s interaction with the International Children’s Digital Library (ICDL). Assessment of the ICDL to Arabic-speaking children as a culturally diverse group was grounded in “representations” and “meaning” rather than in internationalization and localization. The utility of the ICDL navigation controls was judged based on the extent it supported children’s navigation. Most of the ICDL representations and their meanings were found to be highly appropriate for older children but inappropriate for younger ones. The design of the ICDL navigation controls was supportive of children’s navigation. Recommendations for assessing the cross-cultural usability of the ICDL are made and suggestions for system design improvements are provided. 相似文献
16.
Masahiro Niitsuma Masaki Matsubara Masaki Oono Hiroaki Saito 《Information processing & management》2011
The purpose of this study is to develop an automatic basso continuo playing system. In order to find a musically appropriate sequence of chords, we propose the principle of “harmony cost”, which is defined as the sum of two different costs: one is the “local cost” which indicates the unlikelihood of a certain chord allocation and the other is the “transition cost”, which indicates the unlikelihood of a certain connection between two chords. Automatic basso continuo playing is realised by searching for the optimal chord sequence, which minimises the accumulated harmony cost. The proposed method is evaluated by three experiments. Each experiment verifies the effectiveness of the proposed method. 相似文献
17.
The Leiden methodology (LM), also sometimes called the “crown indicator”, is a quantitative method for evaluating the research quality of a research group or academic department based on the citations received by the group in comparison to averages for the field. There have been a number of applications but these have mainly been in the hard sciences where the data on citations, provided by the ISI Web of Science (WoS), is more reliable. In the social sciences, including business and management, many journals and books are not included within WoS and so the LM has not been tested here. In this research study the LM has been applied on a dataset of over 3000 research publications from three UK business schools. The results show that the LM does indeed discriminate between the schools, and has a degree of concordance with other forms of evaluation, but that there are significant limitations and problems within this discipline. 相似文献
18.
Despite a number of studies looking at Web experience and Web searching tactics and behaviours, the specific relationships between experience and cognitive search strategies have not been widely researched. This study investigates how the cognitive search strategies of 80 participants might vary with Web experience as they engaged in two researcher-defined tasks and two participant-defined information seeking tasks. Each of the two researcher-defined tasks and participant-defined tasks included a directed search task and a general-purpose browsing task. While there were almost no significant performance differences between experience levels on any of the four tasks, there were significant differences in the use of cognitive search strategies. Participants with higher levels of Web experience were more likely to use “Parallel player”, “Parallel hub-and-spoke”, “Known address search domain” and “Known address” strategies, whereas participants with lower levels of Web experience were more likely to use “Virtual tourist”, “Link-dependent”, “To-the-point”, “Sequential player”, “Search engine narrowing”, and “Broad first” strategies. The patterns of use and differences between researcher-defined and participant-defined tasks and between directed search tasks and general-purpose browsing tasks are also discussed, although the distribution of search strategies by Web experience were not statistically significant for each individual task. 相似文献
19.
Mauro Lombardi 《Research Policy》2003,32(8):1443-1462
The aim of this paper is to propose an explanation of the changes of dynamic matching between systemic properties of local production systems (LPS) and characteristics of the competitive environment. An evolutionary sequence travelled during the last three decades by Italian LPS is identified and an explanation of long-term dynamics is based on how information flows and knowledge are structured within a local environment. The “traditional” pattern of interlocking behaviours of different agents is defined as cognitive architecture, which evolutionarily emerges as invisible mind. Evolutionary pressures lead new patterns of relationships and interlocking behaviours, which we define as a tendency for more visible “minds” to assert themselves. 相似文献
20.
Richard R. Nelson 《Research Policy》2008,37(1):1-11
In recent years “institutions” have again become a central focus of economists and other scholars studying the processes of economic growth, and the reasons why nations have differed so greatly in their achievements on this front. However, with few exceptions the exploration of the role of institutions has not been connected with a coherent analysis of the relationships between institutions and institutional change and technological advance. This paper proposes a way of analyzing these relationships. The concept of “social technologies” which support “physical technologies” plays a key role in the analysis. 相似文献