From Self-Innovation to International Standardization: A Case Study of TD-SCDMA in China

Yan Hui 서울대학교 경제연구소 2013 Seoul journal of economics Vol.26 No.1

Time Division Synchronous Address (TD-SCDMA ) is one of three 3G standards in China, the two others being Wideband Code Division Synchronous Address (WCDMA) from Europe and Code Division Synchronous Address (CDMA2000) from the US. TD-SCDMA is a Chinese-developed standard currently applied only in the Chinese market. From the very beginning, TD-SCDMA has caught tremendous attention. As a government-led standardization, it demands continuous technical progress, industry accumulation, and national confidence. At the time of its inception, China was not yet the second largest economy in the world; furthermore, as a developing country and technology latecomer, it faced many difficulties and challenges. Thus, it is interesting to note how the Chinese government reached the decision to apply standardization and prepare the relevant conditions to fully commercialize TD-SCDMA in China. After five years of TD-SCDMA application, more information has become available to help answer the questions above. Thus, in the current paper, we introduce the evolution of TD-SCDMA, from its very early stage technology to a standard approved by the International Telecommunication Union (ITU), until its first launch during the 2008 Beijing Olympic Games. The paper provides arguments and evidence to show that TD-SCDMA is a successful case because it has been selected by the ITU as one of the 3G standards for commercial application, even though it is a standard used only domestically in a country, which is considered a technology latecomer with low technological capabilities.

Evaluation and validation of reference genes for SYBR Green qRT-PCR normalization in Sesamia inferens (Lepidoptera: Noctuidae)

Yanhui Lu,Xu-Song Zheng,Qi Liang,Hong-Xing Xu,Yajun Yang,Junce Tian,Xiaochan He,Zhong-Xian Lu 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.4

The pink stemborer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae), has gradually become amajor threat to rice production in Asian rice growth area. Using reverse-transcription quantitative real-time PCR (qRT-PCR) to investigate gene expression of S. inferens under different conditions is a popular technique. However, numerous studies demonstrate that the experimental conditions affect the stability of reference genes. Thus, it is necessary to normalize qRT-PCR data under a specific condition using a stable reference gene as an internal control. In the present study, five algorithms (Delta Ctmethod, Bestkeeper, geNorm,Normfinder, and RefFinder) and seven candidate reference genes were evaluated to find out the most suitable reference genes under different biotic and abiotic conditions including different tissues and developmental stages, exposure to insecticides, different rice varieties, and different diets. Our results showed that the more stable series of reference genes were as follows: GAPDH, RPL10, and RPS3 for different tissues;GAPDH and RPS3 for developmental stages; RPS3 and EF1 for larval insecticide exposure; RPS3 and RPL10 for larvae reared on different rice varieties; RPS3 and ACTB for larvae fed on different diets. Hence, a combination of the best sets of reference genes for normalization of expression analysis will increase the accuracy and reliability of qRT-PCR data in S. inferens. In addition, these results establish the basis for selection of reference genes in other lepidopterous insect species.

Web-Based Collaborative Learning System and Its Key Techniques

Yanhui Xia,Zhengyou Wang,Yi Li,Jinfeng Hu 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.12

On the basis of concept, characteristics and related work of collaborative learning, this paper proposes an intelligent web collaborative learning system prototype based on multi-agent technology. At first, the paper introduces a collaborative learning framework which supporting group learning and illustrates the whole learning process. Secondly, the paper presents some key issues to implementation of the virtual learning environment, such as intelligent grouping, automatic question answering, knowledge management, and opinion mining. Preliminary learning practice shows that it is a practical and efficient way.

An Improved H.264 Encoded Algorithm Based on Weber-Fechner Law

Yanhui Xia,Baisheng Nie,Zhengyou Wang,Liying Li,Jianhua Ming,Zheng Wan,Shuying Huang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.9

With the study of human visual system (HVS), people find that the human eye shows different degree of sensitivity to different light signals. A higher background brightness region of the human eye for the distortion, the degree of sensitivity will be greatly reduced. The human eye’s sensitivity will be greatly reduced to the distortion of a higher brightness background region. This finding is discribed in Weber-Fechner law. Therefore, the encoder can be improved by employing this characteristic of human visual system. In this paper, the authors use this characteristic to improve the H.264 video coding algorithm. In order to improve the compression efficiency of encoder, give the brightness of different regions with different levels of quantification by adjusting the quantization step size (QP), without affecting the subjective quality of video. Experimental results show that the output bit rate decrease up to 10% -20% by using this improved algorithm in H.264 reference encoder, and the subjective quality of decoded image by using this improved algorithm is as good as the standard H.264 encoders.

FINITE ELEMENT MODELING FOR CONCRETE RANDOM PARTICLE MODEL

YanHui Yin,HaiWen Wang 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-

How to select the reasonable aggregate based on the engineering need and the actual condition of the locality and perform effectually computational simulation base on the type of the aggregate is important. This paper generalize the affection of all kinds of parameters of the aggregate to the concrete function base on the importance of concrete aggregate and lots of engineering background. The geometrical representation and finite element mesh of concrete random particle model are all generated automatically in this paper.

Developing an Instrument of Assessing the Middle School Students’ Perceptions of Mathematics Teachers’ PCK

( Yanhui Xu ) 한국수학교육학회 2020 수학교육연구 Vol.23 No.1

Many researches proposed different models and concepts for the PCK. It is important to understand its composition. Most studies investigated the development of PCK and its influence on students’ learning from the teachers’ perspectives. We developed an instrument for assessing middle school students’ perceptions of mathematics teachers’ PCK (SPOMTPCK) to investigate the nature of PCK. Theoretical claims and empirical research in PCK were used to design questions and sub-scales for the SPOMTPCK. The face validity of the instrument was established by the expert mathematics teachers and students. A questionnaire consisting of 38 items on a five-point Likert-type scale was used for data collection from 799 middle school students. The exploratory factor analyses resulted in the development of a three-factor scale of 17 items that was proved valid and reliable, that is, pedagogical representation, understanding students and curriculum, and encouraging students’ engagement. The Cronbach α coefficients of the scale was 0.935, and the Cronbach α coefficient of three factors were ranged from 0.721 to 0.912. The confirmatory factor analysis showed that the questionnaire has good construct validity and the fit indexes are good. MANOVA analysis of variance revealed that the differences in mathematics teachers’ PCK identified by students of different school types and grades were statistically significant. It is a validate measurement to evaluate the perceived mathematics teachers’ PCK for middle school students.

Viscosity evaluation of Fe–Ni–Co ternary alloy from the measured binary systems

Yanhui Liu,Xuewei Lv,Chenguang Bai,Pingsheng Lai,JinSheng Wang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

The iso-viscosity curves of liquid Fe–Ni–Co ternary alloys at 1600 8C were investigated with consideringthe excess viscosity of ternary alloy by the means of three models (Kohler, Toop and Chou) from themeasured sub-binary data in this work. Excess viscosities were used instead of excess thermodynamicproperties in geometrical models, and the excess viscosities of the sub-binary systems were fit by usingthe 3rd degree (n = 3) Redlich–Kister polynomial. The increase of Ni content results in the decrease of theviscosity of the ternary alloy, while Fe has opposite effect. When the molar content of Ni within the alloydoes not exceed 50%, the increase of Co lowers the viscosity. Once its content is above 50%, Co canpromote the increase of the viscosity of the ternary alloy. Similarity coefficients of the Fe–Ni, Fe–Co andNi–Co three binary systems mentioned in the Chou model have been calculated and their values are 0.82,0.20 and 0.47, respectively, showing that the Fe–Ni–Co ternary system is not exactly the ‘‘Kohler model’’or ‘‘Toop model’’, so both Kohler model and Toop model cannot obtain the accurate predicted values. Thepredicted iso-viscosity curves calculated by the Chou model should be recommended. Some activationenergies of the ternary alloy were calculated by the three models and compared with three sub-binarysystems, and the evaluated activation energies calculated by the Chou model should be recommended. Except the sample AE3 and AE6, other activation energy values predicted by three different models aresimilar by a narrow margin. The activation energies for AE3 and AE6 are the lowest and highest,respectively, because of the mix effect of the ternary alloy.

Three‑mode one‑cycle controlled current‑source single‑stage multi‑input high‑frequency‑link inverter

Yanhui Qiu,Daolian Chen 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.1

A current-source single-stage multi-input high-frequency-link grid-connected inverter and a three-mode one-cycle control strategy are proposed and deeply investigated in this paper. The inverter contains multiple current-source inverting units, a multi-input high-frequency transformer, and a cycloconverter. It achieves single-stage power conversion and high-frequency galvanic isolation with a simple circuit structure. The control strategy adds a by-pass switch to the energy storage inductor. It has energy-storing, energy-releasing, and three by-pass operation modes in a low frequency cycle. Through calculating the energy-releasing duty cycle in real time, the magnetic saturation problem of current-source inverters is solved and the output waveform quality is greatly improved. Soft-switching of the converter, a transfer function block diagram, and the design of the main circuit parameters are achieved. The simulation of a three-input inverter and experiment on a two-input inverter verify the feasibility and advancement of the proposed circuit topology and control strategy.

Detection of Voltage Sag using An Adaptive Extended Kalman Filter Based on Maximum Likelihood

Yanhui Xi,Zewen Li,Xiangjun Zeng,Xin Tang 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

An adaptive extended Kalman filter based on the maximum likelihood (EKF-ML) is proposed for detecting voltage sag in this paper. Considering that the choice of the process and measurement error covariance matrices affects seriously the performance of the extended Kalman filter (EKF), the EKF-ML method uses the maximum likelihood method to adaptively optimize the error covariance matrices and the initial conditions. This can ensure that the EKF has better accuracy and faster convergence for estimating the voltage amplitude (states). Moreover, without more complexity, the EKF-ML algorithm is almost as simple as the conventional EKF, but it has better anti-disturbance performance and more accuracy in detection of the voltage sag. More importantly, the EKF-ML algorithm is capable of accurately estimating the noise parameters and is robust against various noise levels. Simulation results show that the proposed method performs with a fast dynamic and tracking response, when voltage signals contain harmonics or a pulse and are jointly embedded in an unknown measurement noise.

Does the Market Listen to the Government? Evidence from China Central Television

Yanhui Jiang,Yun Hong 한국증권학회 2020 Asia-Pacific Journal of Financial Studies Vol.49 No.3

This study explores the asset-pricing function of CCTV (China Central Television) News in China. Results show that the economic focus and economic tone of CCTV News positively predict future aggregate stock market returns. We also find that the CCTV News economic focus betas and tone betas are positively related to cross-sectional excess returns. The influence mechanism tests indicate that institutional investors decipher and absorb information from CCTV News faster and more effectively than retail investors. Finally, informed traders’ and analysts’ positive responses to CCTV News may partly explain the short-term stock market reaction.