排序方式： 共有121条查询结果，搜索用时 31 毫秒
61.
Sonja Sheridan Joanna Giota You-Me Han Jeong-Yoon Kwon 《Early childhood research quarterly》2009,24(2):142-156
The aim of the study is to explore cross-cultural similarities and differences in preschool quality in South Korean and Swedish preschools as measured by two national adaptations of the Early Childhood Environment Rating Scale (ECERS). The approach adopted is that cross-cultural comparisons of preschool quality are both achievable and of great importance to researchers as well as policy-makers, educators, teachers and parents. The results indicate that Swedish childcare programs rate higher on the entire ECERS and all of the individual subscales. The similarities and differences in preschool quality are interpreted within the socio-cultural context of each country and the respective pedagogical goals for preschool. 相似文献
62.
In this work, a sampled-data control problem for neural-network-based systems with an optimal guaranteed cost is investigated. By constructing suitable time-dependent functionals and utilizing an improved free-matrix-based integral inequality, a sampled-data stability criterion for neural-network-based systems is derived. Based on a first result, a sampled-data controller design method for neural-network-based systems that meets the maximum sampling period and minimum guaranteed cost performance is proposed. The superiority and validity of the results will be verified by comparing with the existing results in a numerical example. 相似文献
63.
This paper deals with the problem of delay-dependent stability analysis for neural networks with time-varying delays. First, by constructing an augmented Lyapunov–Krasovskii functional and utilizing a generalized free-weighting matrix integral inequality, an improved stability criterion for the concerned network is derived in terms of linear matrix inequalities. Second, by considering a marginal augmented vector and modifying a Lyapunov–Krasovsii functional, a further enhanced stability criterion is presented. Third, a less conservative stability condition in which a relaxed inequality related to activation functions is added is introduced. Finally, three numerical examples are included to illustrate the advantage and validity of the proposed criteria. 相似文献
64.
This study empirically examines whether the research and development (R&D) activities of foreign-owned firms in Japan differ notably from the R&D activities of domestically-owned firms based on a firm-level panel dataset. Our study carefully disentangles the significant differences in R&D investment behavior of subsidiaries due to three different reasons: having a foreign parent, corporate group affiliation, and the degree of relatedness between business units. The results reveal the following. First, firms that are majority-owned by another firm are less active in R&D than independent firms. Second, foreign ownership does not matter if the parent firm is from a G7 country, but R&D intensity is significantly and positively associated with foreign ownership if the parent firm is from a non-G7 country. Finally, for subsidiaries whose business is related to that of their parent firm, the R&D intensity is lower if the parent is a domestic firm, but higher if it is a foreign firm. These findings imply that globalization and the integration of firms may not only affect production patterns and global supply chains, but may also have an important impact on the level of domestic R&D activities. 相似文献
65.
Fabrication methods for the development of multiplexed immunoassay platforms primarily depend on the individual functionalization of reaction chambers to achieve a heterogeneous reacting substrate composition, which increases the overall manufacturing time and cost. Here, we describe a new type of low-cost fabrication method for a scalable immunoassay platform based on cotton threads. The manufacturing process involves the fabrication of functionalized fibers and the arrangement of these fibers into a bundle; this bundle is then sectioned to make microarray-like particles with a predefined surface architecture. With these sections, composed of heterogeneous thread fragments with different types of antibodies, we demonstrated quantitative and 7-plex immunoassays. We expect that this methodology will prove to be a versatile, low-cost, and highly scalable method for the fabrication of multiplexed bioassay platforms. 相似文献
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67.
Kwon Kyungbin Ottenbreit-Leftwich Anne T. Brush Thomas A. Jeon Minji Yan Ge 《Educational technology research and development : ETR & D》2021,69(5):2761-2787
Educational technology research and development - This study investigated how a computer science (CS) problem-based curriculum impacted elementary students’ CS learning and attitudes. Four... 相似文献
68.
Rahman Tazizur Kim Yang Sok Noh Mijin Lee Choong Kwon 《Educational technology research and development : ETR & D》2021,69(2):1325-1351
Educational technology research and development - Social-Media-Based Learning (SMBL) is the use of social-media-based platforms, such as Twitter, Google Plus, Facebook, and YouTube, for learning... 相似文献
69.
Social media rumors are improvised and expressive forms of public opinion that especially arise under uncertain sociopolitical situations. This study utilizes early rumor studies as theoretical framework for textual analysis of Twitter public opinion. A content and semantic network analysis of Twitter messages spread during Korean saber rattling in 2013 was conducted for understanding public opinion in an uncertain context. The results show that, while non-rumor narratives focus on policy-level responses to the threat situation in a similar manner to institutionalized opinion polling, rumors are less concerned with official responses, instead reflective of hegemonic tensions between anti-leftwing political sentiments and the counteractive accounts. Some rumors reveal the public's coping with fears in the form of humor, guesswork, or wishes. Online rumor analysis helps understand how the society's collective memories interact with the current situational uncertainty in shaping public opinions and sentiments. 相似文献
70.
Oliver Joseph Steve Hodges Georgia W. Moore James N. Cohen Allan Jang Yoonsun Brown Scott A. Kwon Kyung A. Jeong Sophia Raven Sara P. Jurkiewicz Melissa Robertson Tom P. 《Research in Science Education》2019,49(6):1783-1808
Research in Science Education - Research into the efficacy of modules featuring dynamic visualizations, case studies, and interactive learning environments is reported here. This quasi-experimental... 相似文献