An experimental study comparing a guided discovery method with two other methods of teaching a primary school science unit     

Rosita Young 《Research in Science Education》1971,1(1):59-78

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Gravity-oriented microfluidic device for uniform and massive cell spheroid formation     

Lee K  Kim C  Young Yang J  Lee H  Ahn B  Xu L  Yoon Kang J  Oh KW 《Biomicrofluidics》2012,6(1):14114-141147

We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours.  相似文献   

Stochastic stability analysis of piecewise homogeneous Markovian jump neural networks with mixed time-delays     

Zheng-Guang Wu  Ju H. Park  Hongye Su  Jian Chu 《Journal of The Franklin Institute》2012,349(6):2136-2150

In this paper, the problem of stochastic stability analysis is considered for piecewise homogeneous Markovian jump neural networks with both discrete and distributed delays by use of linear matrix inequality (LMI) method. Based on a Lyapunov functional that accounts for the mixed time-delays, a delay-dependent stability condition is given, which is formulated by LMIs and thus can be easily checked. Some special cases are also investigated. Finally, a numerical example is given to show the validness of the proposed result.  相似文献   

Product architecture,organizational capabilities and IT integration for competitive advantage     

YoungWon Park  Takahiro Fujimoto  Paul Hong 《International Journal of Information Management》2012

Increasingly, firms recognize the strategic implications of front-end product design for improving total cost effectiveness. Computer-aided design (CAD) is becoming firms’ competitive weapon beyond its traditional function as a product design tool. Yet, it is unclear how the full potential of IT system, particularly the usage patterns of 3D CAD system, may be realized through organizational capabilities. This paper presents a model of IT system configurations and CAD usage patterns. Next, a typology of IT system configurations is presented based on (1) the degree of CAD integration between assembly makers and suppliers and (2) the structure of product design information (i.e., product architecture). The product architecture of four electronic firms illustrates that information integration through organizational capabilities is more important than IT investment itself. The findings suggest that a Korean firm accomplishes a greater level of IT integration compared to the other two Japanese firms and thus attain better market performance. This study offers valuable insight on effective IT integration strategy for competitive advantage in the global market.  相似文献   

Distributed fusion receding horizon filtering for uncertain linear stochastic systems with time-delay sensors     

Il Young Song  Vladimir Shin  Moongu Jeon 《Journal of The Franklin Institute》2012,349(3):928-946

A new distributed fusion receding horizon filtering problem is investigated for uncertain linear stochastic systems with time-delay sensors. First, we construct a local receding horizon Kalman filter having time delays (LRHKFTDs) in both the system and measurement models. The key technique is the derivation of recursive error cross-covariance equations between LRHKFTDs in order to compute the optimal matrix fusion weights. It is the first time to present distributed fusion receding horizon filter for linear discrete-time systems with delayed sensors. It has a parallel structure that enables processing of multisensory time-delay measurements, so the calculation burden can be reduced and it is more reliable than the centralized version if some sensors turn faulty. Simulations for a multiple time-delays system show the effectiveness of the proposed filter in comparison with centralized receding horizon filter and non-receding versions.  相似文献   

Appropriate intellectual property protection and economic growth in countries at different levels of development   总被引：1，自引：0，他引：1  

Yee Kyoung KimKeun Lee  Walter G. Park  Kineung Choo 《Research Policy》2012,41(2):358-375

This paper examines how the role of patents and utility models in innovation and economic growth varies by level of economic development. Using a panel dataset of over 70 countries, we find that patent protection is an important determinant of innovation and that patentable innovations contribute to economic growth in developed countries, but not in developing. Instead, in developing economies, a minor form of intellectual property rights (IPRs) - namely utility models - is conducive to innovation and growth, controlling for other factors. Using Korean firm level data as a case study, we find that utility model innovations contribute to firm performance when firms are technologically lagging and that those minor innovations can be a learning device and thus a stepping stone for developing more patentable inventions later on. Upon reaching higher levels of technological capabilities, firms become more reliant upon patents and less on utility models. Thus the lesson here is that patent protection enhances innovation and economic growth in countries where the capacity to conduct innovative research exists. Where this capacity is weaker, a system that provides incentives to conduct minor, incremental inventions is more conducive to growth. The significance of this paper is to emphasize the importance not just of the strength of IPRs but of the appropriate type of IPRs for economic development.  相似文献   

Congenital atresia of the left main coronary artery in an infant     

Su Ye Sohn  Gi Young Jang  Byung Min Choi 《Journal of Zhejiang University. Science. B》2010,11(7):539-541

Congenital atresia of the left main coronary artery is a rare occurrence, and surgical revascularizationbypass graft is required. We here report a rare case of congenital coronary anomaly in an infant. A 10-month-old male infant was admitted to the hospital with heart failure symptoms. Echocardiographic examinations revealed mitral valve regurgitation and ischemic changes of the anterolateral papillary muscle and chordae. Coronary angiography showed atresia of the left main coronary artery with a severe hypoplastic left anterior descending artery and a circumflex coronary artery. Unfortunately, sudden cardiac arrest occurred after catheterization and the infant did not recover despite of immediate cardiopulmonary resuscitation. Further studies are needed to find a newer diagnostic method to detect coronary anomaly in an infant, and coronary angiography, if necessary, has to be performed very carefully.  相似文献   

Informed choice and deaf children: underpinning concepts and enduring challenges   总被引：3，自引：0，他引：3  

Young A  Carr G  Hunt R  McCracken W  Skipp A  Tattersall H 《Journal of deaf studies and deaf education》2006,11(3):322-336

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High school students' evolving alternative conception related to the volume of gas: A Lakatosian perspective     

Chulkyu Park  Seonyeong Mun  Hun-Gi Hong 《科学教学研究杂志》2024,61(3):674-705

The purpose of this case study, informed by a Lakatosian perspective, is to identify how an alternative conception that originates in present learning but is related directly to subsequent learning contexts can be constructed. Before the study, one of the authors found by accident that a student who had learned about Avogadro's principle and chemical reaction in South Korea constructed an alternative conception related to the volume of gas. Later, we identified seven Korean high school students with the alternative conception through a test and analyzed their underlying understandings qualitatively through interviews. The results show that they had a scientific conception—core conception—and intuitive assumptions about implicit information of external representations—implicit assumptions—in common. The students' implicit assumptions could be divided into three types again: core assumption, auxiliary assumption, and context-inducing assumption. The core assumption, like the core conception, played a significant role in constructing the alternative conception (hard core), while the auxiliary assumptions were incomplete implicit assumptions to protect the alternative conception (protective belt). The context-inducing assumption was an implicit assumption bringing the context of the subsequent curriculum, and the core conception and the core assumption could be interpreted in this induced context. At the end of the study, the implications related to learning progressions were discussed.  相似文献   

Mentoring in the virtual organization: keys to building successful schools and businesses     

Deborah Lavin Colky  William H. Young 《Mentoring & Tutoring: Partnership in Learning》2013,21(4):433-447

Mentoring can take on a whole new perspective when people have a common goal but are in different physical locations. The benefits of virtual mentoring, in other words, mentoring when the mentor and mentee are not geographically co‐located, and which occurs mainly by electronic communication, can be substantial. They include lowered costs, increased access to mentors, and no limitations on space, time, and location. There are also disadvantages to virtual mentoring. Notable among these is the lack of face‐to‐face communication, something that adds another dimension to understanding the tone and attitude of messages between mentors and mentees. This article not only defines and analyzes the concept of mentoring as performed in the virtual organization but also deals with phases of mentoring and types of mentors used in this relatively new work environment. The synthesis of the literature and the authors’ experience results in a list of keys to successful mentoring in the virtual organization. These are: trust, self‐motivation, flexibility, communication skills, and technological skills. In addition, implications for worldwide mentoring are discussed.  相似文献