Opportunistic Decode-and-Forward Cooperation in Mixed Rayleigh and Rician Fading Channels

Changqing Yang,Wenbo Wang,Shuang Zhao,Mugen Peng 한국전자통신연구원 2011 ETRI Journal Vol.33 No.2

We consider a two-hop multiple-relay network implemented with opportunistic decode-and-forward cooperative strategy, where the first hop and second hop links experience different fading (Rayleigh and Rician). We derive the exact expressions of end-to-end outage probability and analyze the approximate results in high signal-to-noise ratio region. The analysis shows that the same diversity order can be achieved even in different mixed fading environments. Simulation results are provided to verify our analysis.

Performance Evaluations of Four MAF-Based PLL Algorithms for Grid-Synchronization of Three-Phase Grid-Connected PWM Inverters and DGs

Yang Han,Mingyu Luo,Changqing Chen,Aiting Jiang,Xin Zhao,Josep M. Guerrero 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

Porous carbon derived from waste corrugated paper with KOH-NaOH mixture and its adsorption property for methylene blue

Yang Mannan,Fang Changqing,Su Jian,Zeng Huilin,Lin Qilang 한국탄소학회 2023 Carbon Letters Vol.33 No.4

In this study, waste corrugated paper was used as carbon precursor with KOH-NaOH mixture (mole ratio was 51:49 and the melting point is 170 °C) as activator to prepare porous carbon at different reaction temperature and different mass ratio of KOH-NaOH mixture/waste corrugate paper fiber. The micro-morphology, pore structure information and composition of porous carbon were analyzed, and the formation mechanism of pores was investigated. The effect of activator amount and pyrolysis temperature on the morphology and structure of porous carbon were studied. The adsorption capacity of porous carbon was evaluated with the methylene blue as model pollutant. The effect of adsorbent amount, adsorption time and temperature on the adsorption performance of the porous carbon were analyzed. The maximum specific surface area is 1493.30 m2·g−1 and the maximum adsorption capacity of methylene blue is 518 mg·g−1. This study provides a new idea for efficient conversion and utilization of waste paper.

Performance Evaluations of Four MAF-Based PLL Algorithms for Grid-Synchronization of Three-Phase Grid-Connected PWM Inverters and DGs

Han, Yang,Luo, Mingyu,Chen, Changqing,Jiang, Aiting,Zhao, Xin,Guerrero, Josep M. The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

Regularization statistical inferences for partially linear models with high dimensional endogenous covariates

Liu Changqing,Zhao Peixin,Yang Yiping 한국통계학회 2021 Journal of the Korean Statistical Society Vol.50 No.1

In this paper, we consider the statistical inferences for a class of partially linear models with high dimensional endogenous covariates, when high dimensional instrumental variables are also available. A regularized estimation procedure is proposed for identifying the optimal instrumental variables, and estimating covariate efects of the parametric and nonparametric components. Under some conditions, some theoretical properties are studied, such as the consistency of the optimal instrumental variable identifcation and signifcant covariate selection. Furthermore, some simulation studies and a real data analysis are carried out to examine the fnite sample performance of the proposed method.

Pharmacist as an Academic Detailer: Benefits and Challenges

Zhenji Jin,Madiha,Changqing Yang 한국병원약사회 2016 病院藥師會誌 Vol.33 No.2

“Academic detailing”(AD) is a form of interactive educational outreach to physicians or other health care staff for providing unbiased, noncommercial, evidence-based information about medications and other therapeutic decisions, with the goal of improving patient care and reducing health care costs. Many trials have been carried out to establish this technique as an effective tool for continuous education of medical staff which in response leads to safe prescribing patterns. In this review we have summarized the studies that evaluated the role of pharmacist as an academic detailer in different settings, targeting different group of medications and achieving different objectives. Some studies that compared academic detailing to other educational methods or technology oriented techniques are also included. Various factors that promote or discourage academic detailing by pharmacist have been discussed. Pharmacist led educational outreach is found to be effective in changing the prescribing behavior, but on the other hand some researchers have observed insignificant effects. Further research is required to determine the best possible structure ensuring fruitfulness of this technique.

Correlation Based Analysis of Parameter Change Propagation in Variant Product Design

Junzhi Shang,Bo Yang,Ning Ma,Changqing Gao 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.4

Analysis of parameter change propagation is essential to ensure the consistency of the product’s integrated content as well as to capture the contextual impacts of a change proposal in variant product design. In this regard, a correlation-based approach is presented in this paper. The propagation of parameter change from one component to another in a product as well as from one key structure to another inside a component are studied. Firstly, a data fl ow model for change propagation as well as the basic units in parameter change propagation is proposed to illustrate the hierarchy and logical correlations between parameters. Then, change propagation network from the perspective of assembly is constructed by introducing “and” operation into the process. Change propagation coefficient is used to describe the change cost, based on which the optimal propagation path between components is selected. Thirdly, matrices are used to describe the correlation between parameters in different components. By introducing inner product into those matrices, change propagation path between parameters in different components can be obtained. Fourthly, the changed components are taken as the studied objects. Parametric correlation graph as well as quantitative expressing method is used to illustrate the parameter linkage inside the components. A searching method for parameter change propagation path inside components based on component modeling process is developed. Finally, the effectiveness of this method is verified by an example of an injection molding machine. The result confirms that our method can provide accurate estimation for the transfer process of the initial parametric change from macro-parameter changes in product to micro-parameter changes in components.

An Adaptive Watermark Detection Algorithm for Vector Geographic Data

( Yingying Wang ),( Chengsong Yang ),( Na Ren ),( Changqing Zhu ),( Ting Rui ),( And Dong Wang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.1

With the rapid development of computer and communication techniques, copyright protection of vector geographic data has attracted considerable research attention because of the high cost of such data. A novel adaptive watermark detection algorithm is proposed for vector geographic data that can be used to qualitatively analyze the robustness of watermarks against data addition attacks. First, a watermark was embedded into the vertex coordinates based on coordinate mapping and quantization. Second, the adaptive watermark detection model, which is capable of calculating the detection threshold, false positive error (FPE) and false negative error (FNE), was established, and the characteristics of the adaptive watermark detection algorithm were analyzed. Finally, experiments were conducted on several real-world vector maps to show the usability and robustness of the proposed algorithm.

Patients’Perception, Satisfaction and Expectations Towards the Role of Clinical Pharmacists in General Hospitals in China

Madiha,Zhenji Jin,Jia-Qi LI,Changqing Yang 한국병원약사회 2016 병원약사회지 Vol.33 No.4

Purpose : Many developed countries have already accepted the indispensable role of clinical pharmacist (CP) in health care system. In past few years, Ministry of Health in China has also worked efficiently to regularize and implement clinical pharmacy services (CPSs). In our study, we opted to access the perception, satisfaction and expectation of patients towards the services provided by CP in hospitals in China. Method : The study was conducted in 10 general hospitals located in 8 different cities in China. Questionnaire was composed of four main parts: 1) Demographics of patients, 2) General awareness about CP, 3) Response regarding CP’s professional capabilities, 4) Satisfaction and expectations regarding different CPSs. The chi-test was performed to examine the statistical significance of association between independent variables and dependent variables. Results : Out of 350 distributed questionnaires, 289 were retrieved giving a response rate of 82%. Most of the respondents know about clinical pharmacist and 39.79% had experienced CPSs before. 75% believed that clinical pharmacist is a drug expert, whereas mostly all agreed that CP is an important member of health care team and should be encouraged to participate in patient therapy. More than 75% of respondents perceive that CP can improve quality and safety of treatment. Among those who had previously experienced CPSs, more than 75% showed satisfaction with CP providing individualized patient care, participating in ward rounds, taking medication history, providing drug information and counseling. And approximately 80% of the remaining, who never experienced, expects CP to execute these tasks except for performing physical examination. Conclusion : Most people in China understand, accept and encourage the role of CP in health care. As patients who experienced CPSs were less, it triggers the need of hiring more clinical pharmacist and allowing them to perform additional interactive roles, so that effective CPSs can be delivered to masses.

MiR-486-5p Suppresses Hepatic Stellate Cells Activation Liver Fibrosis by Targeting Smad2

( Beiyong Cui ),( Xiya Lu ),( Meiyi Song ),( Changqing Yang ) 대한간학회 2021 춘·추계 학술대회 (KASL) Vol.2021 No.1