Iterative Learning Control for Fractional Order Linear Systems with Time Delay Based on Frequency Analysis

Yugang Wang,Fengyu Zhou,Lei Yin,Fang Wan 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.4

To overcome the deficiencies of time delay in the repetitive control of fractional-order linear systems,Pdα -type iterative learning control (ILC) law and P & convolution-type ILC law are designed for input and statetime delay, respectively. Convergence conditions are derived in frequency domain via contraction mapping principle. Besides, the convergence frequency domain of proposed feedback controllers is obtained over a finite frequencyrange to design the controllers effectively. Then, the effectiveness of the proposed theoretical schemes is demonstrated using two numerical examples. The influence of time delay is eliminated, and output trajectory convergence to the desired one is guaranteed. Moreover, the Nyquist diagram of transfer function G(s) and time delay variation are analyzed in frequency domain to reveal the influence of convergence on the system.

Introduction of the Genetic Male Sterile Gene into Pak-Choi (Brassica campestri ssp. chinensis)

Yugang Wang,Hui Feng 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Biodegradable Magnesium Alloy Stents as a Treatment for Vein Graft Restenosis

Yugang Li,Lei Wang,Shanshan Chen,Dan Yu,Weifeng Sun,Shijie Xin 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.5

Purpose: To explore the effects of biodegradable magnesium alloy stents (BMAS) on remodeling of vein graft (VG) anastomoticrestenosis. Materials and Methods: To establish a VG restenosis model, seventy two New Zealand rabbits were randomly divided into threegroups according to whether a stent was implanted in the graft vein or not. BMASs and 316L stainless steel stents were implantedin BMAS and 316L groups, respectively, while no stent was implanted in the no-treatment control group (NC group). Loss of lumendiameter in the graft vein was measured in all three groups. Upon harvesting VG segments to evaluate intimal proliferationand re-endothelization, the degradation and biological safety of the stents were observed to explore the effects of BMAS on VGremodeling. Results: Model establishment and stent implantation were successful. The BMAS reduced lumen loss, compared with the controlgroup (0.05±0.34 mm vs. 0.90±0.39 mm, p=0.001), in the early stage. The neointimal area was smaller in the BMAS group than the316L group after 4 months (4.96±0.66 mm2 vs. 6.80±0.69 mm2, p=0.017). Re-endothelialization in the BMAS group was better thanthat in the 316L group (p=0.001). Within 4 months, the BMAS had degraded, and the magnesium was converted to phosphorusand calcium. The support force of the BMAS began to reduce at 2–3 months after implantation, without significant toxic effects. Conclusion: BMAS promotes positive remodeling of VG anastomosis and has advantages over the conventional 316L stents in thetreatment of venous diseases.

A Study on the Determinants of Income Distribution: Evidence from Macroeconomics

Yugang He,Wang Feng 한국유통과학회 2019 유통과학연구 Vol.17 No.1

Purpose – As the market economy deepens, the issue of social equity caused by income distribution becomes more and more significant. Therefore, this paper attempts to exploit the determinants of income distribution in terms of macroeconomics. Research design, data, and methodology - The data set from 1990 to 2017 will be used to conduct an empirical analysis under a menu of econometric approaches such as vector autoregressive model and impulse response function. The income distribution and other macroeconomic variables such as foreign direct investment and employment will be used to conduct an empirical analysis to explore the determinants of income distribution in terms of macroeconomics. Results - The findings indicate that the income distribution is related with macroeconomics. More specifically, the export, import, GDP and foreign direct investment play a role in deteriorating the income distribution. Conversely, the industrialization, inflation and employment can improve the income distribution. Unfortunately, the inflation and employment do not get through under 5% significant test. Conclusions – Due to that a good income distribution can be beneficial for both a country and an individual, this paper provides a new scope for China’s government to improve its income distribution in terms of macroeconomics.

H∞ Control for Networked Systems with Data Packet Dropout

Yugang Niu,Tinggang Jia,Xingyu Wang 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.2

This paper considers the control problem of networked control systems, respectively, for the two cases that system state is available and unavailable. It is assumed that there exists a communication network in the feedback loop, and multiple data packet dropouts may happen. An estimation method is introduced to compensate the lost data. And then, the design of control is considered for the states available and states unavailable, respectively, and some sufficient conditions are derived such that the closed-loop systems are exponentially mean-square stable with prescribed disturbance attenuation level.

A Study on the Determinants of Social Welfare: Evidence from Macroeconomics

Yugang He,Wang Feng 한국유통과학회 2018 The Journal of Industrial Distribution & Business( Vol.9 No.9

Purpose - Social welfare is a social insurance system that provides funds and services for all citizens to maximize their life quality. Its ultimate goal is to alleviate social contradictions. Therefore, this paper explores the determinants of social welfare in terms of macroeconomics. Research design, data, and methodology - Based on the vector error correction model, the annual time series from 1990 to 2017 will be used to conduct an empirical analysis. The real GDP, the real income, the inflation and the degree of openness will be treated as independent variables. The input of social welfare will be treated as a dependent variable. These variables will be used to perform the cointegration test and the vector error correction model to explore how the macroeconomic variables affect social welfare both in long run and short run. Result - Via the empirical analysis, it can be summarized that the real GDP, the real income and the degree of openness are the driving determinants to enlarge the social welfare. Conversely, the inflation is the obstructive determinant to reduce the social welfare. Conclusion - The positive and negative determinants of social welfare exist simultaneously, China’s government should take macroeconomic regulation and control to balance them to enlarge social welfare.

Sliding Mode Control for a Class of Nonlinear Ito Stochastic Systems with State and Input Delays

Yugang Niu,Bei Chen,Xingyu Wang 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.3

This paper deals with the problem of sliding mode control (SMC) for a class of nonlinear stochastic systems. The nonlinear uncertainties are unknown and unmatched. There exist state and input delays. A special switching function is designed such that the insensitivity of the system can be guaranteed throughout the entire response of the system from the initial time instance. Both the sliding surface and the sliding mode controller exist if a set of matrix inequalities is feasible. A simulation example is given to illustrate the proposed method.

What Role does China’s Outward Foreign Direct Investment Play in Economic Growth of Korean Peninsula?

( Yugang He ),( Baek-ryul Choi ),( Renhong Wu ),( Jingnan Wang ) 이화여자대학교 통일학연구원 2020 Journal of peace and unification Vol.10 No.2

This paper contributes to the present research stream by exploring the effect of China’s OFDI over the period 2003-2019 in the case of Korean peninsula. On account of the auto-regressive distributed lag model and Granger causality approach of vector error correction, an inference is drawn that China’s OFDI significantly contributes to the economic growth in Korean peninsula whenever in the short run and long run. However, this kind of contribution is asymmetric in which the contribution of China’s OFDI to North Korea’s economic growth is greater than that of South Korea. Moreover, the long-run causality results originate the bi-directional causality between China’s OFDI and economic growth in Korean peninsula.

A Panel Analysis on the Cross Border E-commerce Trade: Evidence from ASEAN Countries

Yugang He,Jingnan WANG 한국유통과학회 2019 The Journal of Asian Finance, Economics and Busine Vol.6 No.2

Along with the economic globalization and network generalization, this provides a good opportunity to the development of cross-border ecommerce trade. Based on this background, this paper sets ASEAN countries as an example to exploit the determinants of cross-border ecommerce trade including the export and the import, respectively. The panel data from the year of 1998 to 2016 will be employed to estimate the relationship between cross-border e-commerce trade and relevant variables under the dynamic ordinary least squares and the error correction model. The findings of this paper show that there is a long-run relationship between cross-border e-commerce trade and relevant variables. Generally speaking, the GDP(+) and real exchange rate(-export & +import) have an effect on cross-border e-commerce trade. However, the population (+) and the terms of trade (-) only have an effect on cross-border e-commerce import. The empirical evidences show that the GDP and the real exchange rate always affect the development of cross-border e-commerce trade. Therefore, all ASEAN countries should try their best to develop the economic growth and focus on the exchange rate regime so as to meet the need of crossborder e-commerce trade development.

Effect of Foreign Direct Investment on Economic Growth: New Evidence from OECD Countries

Wang, Mengzhen(왕몽진),Choi, Baek-ryul(최백렬),He, Yugang(하육강) 전북대학교 산업경제연구소 2021 아태경상저널 Vol.13 No.1

본 연구는 외국인직접투자가 경제성장에 미치는 영향을 분석하기 위하여 26개 OECD 국가를 대상으로 2007년부터 2017년까지의 패널 데이터를 사용하여 고정효과모형을 설정하여 분석했다. 기존 연구에서 외국인직접투자 및 경제성장은 아직 불분명한 관계이어서 본 연구에 비교적 최근의 데이터를 사용하여 측정하려 한다. 실증분석 결과로는 외국인직접투자, 국내투자, 인적자본 및 수출은 모두 경제성장에 긍정적인 영향을 미치는 것으로 나타났으나, 국내투자 및 수출보다 외국인직접투자가 경제성장에 미치는 긍정적인 영향은 비교적 작다고 판단된다. 이외에는 국내저축 및 노동력 변수는 통계적인 의미를 가지지 않음으로 나타났다. 따라서 안정적인 거시경제 환경을 유지하기 위한 정책적인 지원 등을 취함으로써 외국인직접투자 유치에 힘을 기울려야 하며, 수출 촉진 및 국내투자 증대를 장려하는 정책적인 조치도 필요하다. To verify the impact of foreign direct investment on economic growth in OECD countries, this study adopts a two-way fixed-effect model to analyzes panel data composed of twenty-six OECD countries from 2007 to 2017. The literature based on the relationship of foreign direct investment on economic growth had no consensus. This study uses the latest data to provide strong evidence for the growth effect of foreign direct investment. The empirical results confirm that foreign direct investment, domestic investments, exports, and human capital are positively associated with economic growth. Although, the growth impacts of domestic investments and exports are higher than that of foreign direct investment. It also illustrates that foreign direct investment is one of the important channels to promote economic growth. The findings suggest that policymakers need to create a suitable economic environment, like maintaining macroeconomic stability and reducing the market distortion, to attract foreign direct investment and then provide policy support to increase domestic investments and exports.