An accurate analytical formula for the essential joint probability of framed slotted aloha protocols     

In-Hang Chung  Ming-Ching Yen  Chi-Kuang Hwang 《Journal of The Franklin Institute》2013,350(10):3432-3440

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A Systematic Analysis of Experimental Studies Targeting Fractions for Students with Mathematics Difficulties     

Jiwon Hwang  Paul J. Riccomini  Seok Yoon Hwang  Stephanie Morano 《Learning disabilities research & practice》2019,34(1):47-61

Developing an understanding of fractions is critical and is an educational focus, as reflected in national standards and principles. This study conducted a quantitative synthesis of 22 experimental studies to investigate the overall efficacy of previously conducted fraction interventions compared to standard instruction. Instruction type and achievement level were used to examine variations of the effect sizes. The results indicated that intervention was more effective than standard instruction only in problem‐solving domains, and the effects were differentiated by instruction type and achievement level. This study provides a diagnostic view of the current state of U.S. mathematics education on fractions, along with insights for future directions in fraction instruction, particularly focusing on students with mathematics difficulties. Educational implications and limitations are discussed.  相似文献   

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes     

Hu-zhe Zheng  In-Wook Hwang  Shin-Kyo Chung 《Journal of Zhejiang University. Science. B》2009,10(12):912-919

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7,50 ℃ for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3,1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8,4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production.  相似文献   

Exploiting indoor location and mobile information for context-awareness service     

Hyun-Yong Noh Author VitaeJin-Hyung Lee Author Vitae  Sae-Won Oh Author VitaeKeum-Sung Hwang Author Vitae  Sung-Bae Cho^{Author Vitae} 《Information processing & management》2012,48(1):1-12

Personal mobile devices such as cellular phones, smart phones and PMPs have advanced incredibly in the past decade. The mobile technologies make research on the life log and user-context awareness feasible. In other words, sensors in mobile devices can collect the variety of user’s information, and various works have been conducted using that information. Most of works used a user’s location information as the most useful clue to recognize the user context. However, the location information in the conventional works usually depends on a GPS receiver that has limited function, because it cannot localize a person in a building and thus lowers the performance of the user-context awareness. This paper develops a system to solve such problems and to infer a user’s hidden information more accurately using Bayesian network and indoor-location information. Also, this paper presents a new technique for localization in a building using a decision tree and signals for the Wireless LAN because the decision tree has many advantages which outweigh other localization techniques.  相似文献   

Do Teachers’ Instructional Practices Moderate Equity in Mathematical and Scientific Literacy?: an Investigation of the PISA 2012 and 2015     

Jihyun Hwang  Kyong Mi Choi  Yejun Bae  Dong Hoon Shin 《International Journal of Science and Mathematics Education》2018,16(1):25-45

Many efforts have been made to reach educational equity, especially to reduce mathematics and science achievement gaps by students’ socioeconomic status. Across countries, educators strive to reform traditional teacher-centered instructional approaches to more student-centered/inquiry-based instruction to improve equity in education. In this context, this study examines whether relationships between socioeconomic status and scientific or mathematical literacy are moderated by student-centered instruction. Ten countries covering a wide range of achievement levels as well as equity in education are selected for an international comparison. A linear regression analysis is applied to student achievement, equity, and frequency of student-centered instruction data from the PISA 2012 and PISA 2015. We find mixed results: As student-centered instruction is offered more frequently, the gap in mathematical and scientific literacy between low and high socioeconomic status is generally narrowed or maintained. In most countries, students’ mathematical and scientific literacy scores are expected to decrease across all socioeconomic status as student-centered instruction is given more frequently. The findings necessitate further scrutiny of how teachers implement student-centered instruction in various educational systems. This further research need to consider the complexity of implementation related to sociological and pedagogical aspects.  相似文献   

An exact closed-form formula of collision probability in diverse multiple access communication systems with frame slotted aloha protocol     

Kun-Shu Huang  Chi-Kuang Hwang  Bore-Kuen Lee  In-Hang Chung 《Journal of The Franklin Institute》2017,354(13):5739-5752

For diverse multiple access communication systems based on frame slotted aloha (FSA) protocol, it is important to analyze collision probability for the system performance evaluation. As shown in the literature, for general settings, it is difficult to derive an exact and closed-form solution for collision probability without approximation. Recently, an exact solution based on generic analytical approach (GAA) [31] has been proposed, yet its numerical computation will become difficult when the number of slots is larger than 16. In this paper, we develop an exact closed-form formula (ECFF) for collision probability that can not only overcome the computational deficiency of GAA in the presence of a large number of slots, but also reduce the computation complexity of collision probability. Surprisingly, by introducing a differentiation operator to form a hybrid recursive equation and applying various algebraic properties of Laplace transform and Z transform, the final collision probability can be represented by a compact double summation. Accuracy of the ECFF and comparison with the GAA have been studied by Monte Carlo simulation.  相似文献   

Quantum lithography: A?non-computing application of quantum information     

Colin Williams  Pieter Kok  Hwang Lee  Jonathan P. Dowling 《Informatik - Forschung und Entwicklung》2006,70(3):73-82

Quantum information theory holds the promise of revolutionizing technologies other than computing and communications. In this article we show how quantum entanglement can be harnessed to beat the Rayleigh diffraction limit of conventional optical lithography, and to permit nano-devices to be fabricated at a scale arbitrarily shorter than the wavelength used. Given the relative ease of performing optical lithography compared with other schemes, and the relative costs associated in migrating the lithography industry to each new fabrication technology, exploiting quantum entanglement to extend the useful life of optical lithography could be economically attractive.  相似文献   

An investigation of attitudes of students and teachers about participating in a context‐aware ubiquitous learning activity     

Ju‐Ling Shih  Hui‐Chun Chu  Gwo‐Jen Hwang  Kinshuk 《British journal of educational technology : journal of the Council for Educational Technology》2011,42(3):373-394

In recent years, digital learning has been converting from e‐learning to m‐learning because of the significant growth of wireless and mobile computing technologies. Students can learn any time and any where with mobile devices. Consequently, context‐aware ubiquitous learning (u‐learning) is emerging as a new research area. It integrates wireless, mobile and context awareness technologies in order to detect the situation of the learners and provide more seamless adaptive support in the learning process. In this paper, a context‐aware u‐learning environment is developed for learning about campus vegetation in elementary schools based on an innovative approach by employing repertory grid method in designing learning content. In addition, we probe the feasibility of context‐aware u‐learning in courses by soliciting feedback from the students and teachers through interviews and questionnaires. The findings reveal that the environment is capable of enhancing students’ motivation and learning effectiveness. Moreover, it is also capable of reducing the teaching load while enabling better control of class order.  相似文献   

The Academic Credit Bank System in the Republic of Korea: An effective medium for lifelong learning in higher education?     

Park  Hyewon  Choi  Jinhee  Kim  JungHwan  Hwang  Jihee 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2019,65(6):975-990

International Review of Education - Drawing on critical theory for adult education, the authors of this article examine the Academic Credit Bank System (ACBS), an open educational system operating...  相似文献   

中国安息香科的初步研究     

黄淑美 《中国科学院研究生院学报》1980,18(2):154-167

 The present paper is a result of taxonomic study of Chinese Styracaceae plants. It contains 9 genera, 48 species, of which 2 species, 2 varieties are described as new and 2 new combinations are made, 21 species or varieties previously known to botanists distinctly are here reduced to synonyms.  Besides  the  author  also  discuss about itsgeographical distribution in China and the main systematic characteristics of Styrax.  相似文献