An experience of teaching for learning by observation: Remote-controlled experiments on electrical circuits

In order to facilitate senior primary school students in Hong Kong to engage in learning by observation of the phenomena related to electrical circuits, a design of a specific courseware system, of which the interactive human–machine interface was created with the use of an open-source software called the LabVNC, for conducting online remote-controlled experiments was developed in this study. The statistically significant results of a pre-test–post-test evaluation study showed that the LabVNC-based system has potential to promote students to learn the target topic under the approach of learning by observation. The assertion of the teacher on the pedagogical value of the remote-controlled experimentation and the enthusiasm of students in using the LabVNC-based system reveal the potential to integrate the use of the LabVNC-based system with the practice of scientific experiments. Based on the feedback from the teacher and students, the existing LabVNC-based system will be refined under the design-based research approach.     

Zinc(II) complex of terpyridine-crown macrocycle: A new motif in fluorescence sensing of zwitterionic amino acids

A new fluorescence macrocyclic receptor based on the Zn(II) complex of a C₂-terpyridine and a crown ether has been developed for molecular recognition of zwitterionic amino acids in water/DMF solution with remarkable selectivity towards l-aspartate (K = 4.5 × 10⁴ M⁻¹) and l-cysteine (K = 2.5 × 10⁴ M⁻¹).     

Size-Reduced Rectangular Patch Hybrid Coupler Using Patterned Ground Plane

This paper presents, for the first time, the design of a size-reduced rectangular patch hybrid coupler. Different types of compact rectangular patch hybrid couplers with different ground plane patterns are described. For demonstration, two compact rectangular patch hybrid couplers are designed to operate at 3.5 GHz. They are measured to have 30.1% and 33.3% bandwidth with 67.3% and 72.3% size reduction compared with the optimized one without patterned ground plane.     

Mode-Based Beamforming Arrays for Miniaturized Platforms

In this paper, a new and practical mode-based array concept is proposed. The key principle of this mode-based approach is the use of orthogonal radiation modes existing in highly coupled arrays as individual information channels so as to avoid mutual coupling and correlation. Consequently, mode-based arrays can be very compact in size but without suffering undesired effects such as impedance mismatch or pattern distortion. While providing a general theoretical discussion for this mode-based approach, a practical application example, namely, a compact electronically scanning array module is developed. With a suitable signal combining algorithm, the module is capable of forming and full 360^deg scanning of a high-gain radiation pattern in the azimuth plane. An experimental prototype has been fabricated on a traditional printed circuit board to validate the practicability of the proposed concept. Measurement results obtained are in good agreement with theoretical simulations, showing promising potential of mode-based array modules for modern miniaturized wireless devices.     

An Iterative Algorithm and Low Complexity Hardware Architecture for Fast Acquisition of Long PN Codes in UWB Systems

Rapidly acquiring the code phase of the spreading sequence in an ultra-wideband system is a very difficult problem. In this paper, we present a new iterative algorithm and its hardware architecture in detail. Our algorithm is based on running iterative message passing algorithms on a standard graphical model augmented with multiple redundant models. Simulation results show that our new algorithm operates at lower signal to noise ratio than earlier works using iterative message passing algorithms. We also demonstrate an efficient hardware architecture for implementing the new algorithm. Specifically, the redundant models can be combined together so that substantial memory usage can be reduced. Our prototype achieves the cost-speed product unachievable by traditional approaches. This work was supported in part by the Army Research Office DAAD19-01-1-0477 and the National Science Foundation CCF-0428940. On Wa Yeung received the B. Eng. degree in Electronic Engineering from the Chinese University of Hong Kong, Hong Kong in 1994 and MSEE from the University of Southern California (USC) in 1996. In 1997–2003, he was a hardware engineer in Hughes Network Systems, San Diego, CA, designing hardware platforms for fixed wireless and satellite terminals. He is currently working towards the Ph.D. degree in EE at USC. His research interests are in the areas of iterative detection algorithms and their hardware implementation. Keith M. Chugg (S'88-M'95) received the B.S. degree (high distinction) in Engineering from Harvey Mudd College, Claremont, CA in 1989 and the M.S. and Ph.D. degrees in Electrical Engineering (EE) from the University of Southern California (USC), Los Angeles, CA in 1990 and 1995, respectively. During the 1995–1996 academic year he was an Assistant Professor with the Electrical and Computer Engineering Dept., The University of Arizona, Tucson, AZ. In 1996 he joined the EE Dept. at USC in 1996 where he is currently an Associate Professor. His research interests are in the general areas of signaling, detection, and estimation for digital communication and data storage systems. He is also interested in architectures for efficient implementation of the resulting algorithms. Along with his former Ph.D. students, A. Anastasopoulos and X. Chen, he is coauthor of the book Iterative Detection: Adaptivity, Complexity Reduction, and Applications published by Kluwer Academic Press. He is a co-founder of TrellisWare Technologies, LLC, where he is Chief Scientist. He has served as an associate editor for the IEEE Transactions on Communications and was Program Co-Chair for the Communication Theory Symposium at Globecom 2002. He received the Fred W. Ellersick award for the best unclassified paper at MILCOM 2003.     

芜湖至宣州高速公路软土地基路堤稳定控制

在软土地基修筑高速公路 ,路基的稳定控制是建设中必然面临的问题。作者通过在芜宣高速公路软基试验路工程的具体实践和对现场观测数据的分析 ,针对不同条件进行了稳定计算 ,在此基础上 ,根据国内外相关工程经验 ,提出了为确保路基稳定的施工速率控制方法与控制标准。     

MALDI‐TOF MS characterization of proanthocyanidins from cranberry fruit (Vaccinium macrocarpon) that inhibit tumor cell growth and matrix metalloproteinase expression in vitro

Proanthocyanidin‐rich extracts were prepared by fractionation of the fruit of the North American cranberry (Vaccinium macrocarpon). In vitro growth inhibition assays in eight tumor cell lines showed that selected fractions inhibited the growth of H460 lung tumors, HT‐29 colon and K562 leukemia cells at GI₅₀ values ranging from 20 to 80 µg ml^?1. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) of one of these fractions found it to be composed of polyflavan‐3‐ols, which are primarily tetramers through heptamers of epicatechin containing one or two A‐type linkages. Whole cranberry extract and the proanthocyanidin fractions were screened for effect on the expression of matrix metalloproteinases in DU 145 prostate carcinoma cells. The expression of MMP‐2 and MMP‐9 was inhibited in response to whole cranberry extract and to a lesser degree by the proanthocyanidin fractions. Copyright © 2005 Society of Chemical Industry     

车载影音系统的图像处理器

移动视频应用 近来,移动视频已经发展成为可行甚至是必要的车载娱乐系统的一个配件.几款新型的休闲车和小型商务车的卖点就是把移动视频作为选配件,越来越多的人已经考虑在他们的车上加装视频娱乐系统.     

A Mechanism for Error Detection in Speeded Response Time Tasks.

The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors by identifying states of the system associated with negative value. The mechanism is formalized in a computational model based on a recent theoretical framework for understanding error processing in humans (C. B. Holroyd & M. G. H. Coles, 2002). The model is used to simulate behavioral and event-related brain potential data in a speeded response time task, and the results of the simulation are compared with empirical data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acceleration of plasminogen activation by tissue plasminogen activator on surface-bound histidine-proline-rich glycoprotein

Histidine-proline-rich glycoprotein (HPRG), also known as histidine-rich glycoprotein, is a major plasminogen-binding protein. In this work we characterized extensively the circumstances under which HPRG accelerates plasminogen activation and the specificity of this effect. Soluble HPRG did not significantly influence plasminogen activation. In contrast, native HPRG bound to hydrazide or nickel chelate surfaces strongly stimulated the activation of plasminogen by tissue plasminogen activator, but not by urokinase or streptokinase. The efficiency of activation on surface-bound HPRG was increased for Glu-plasminogen (41-fold), Lys-plasminogen (17-fold), and cross-linked Glu-plasminogen (11-fold) but not for mini-plasminogen, and was mainly due to a decrease in the apparent Km. A reduced susceptibility to inhibition by chloride ions contributed to the higher activation rate of Glu-plasminogen on an HPRG surface. The immobilized N- and C-terminal domains, but not the histidine-proline-rich domain of HPRG, also bound plasminogen and stimulated its activation. HPRG-enhanced plasminogen activation was proportional to the quantity of HPRG immobilized and was abolished by anti-HPRG antiserum, by low concentrations of epsilon-aminocaproic acid, by methylation of lysine residues in HPRG, and by treatment of HPRG with carboxypeptidase B. Soluble HPRG and a plasminogen fragment, kringle 1-2-3, acted as competitive inhibitors by binding to plasminogen and immobilized HPRG, respectively. The interaction of the conserved C-terminal lysine of HPRG with the high affinity lysine binding site of plasminogen is necessary and sufficient to accelerate plasminogen activation. Unlike other stimulators of plasminogen activation, the effect of HPRG on fibrinolysis is modulated by factors that influence the equilibrium between solution and surface-bound HPRG.