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Search Results: 1 - 10 of 3284 matches for " Shiyu Shang "
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The Impact of Policy Intervention on Regional Economic Growth in China  [PDF]
Lidan Yu, Shiyu Shang
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.912137
Abstract: As a grand policy of realizing the rapid development of the western region and narrowing the income gap between the western region and the eastern and central regions after China’s reform and opening up, it is of great practical significance to objectively study its policy effects. This paper uses the data of municipal districts in Chinese cities from 1997 to 2014 in China City Statistical Yearbook to evaluate the policy effect of the western development strategy by using the method of difference-in-difference propensity score matching (PSM-DID). The research results show that the western development policy has not improved the economic growth of the western region, but has negatively affected the economic growth of the western region. In addition, economic growth in the western region may be due to factors such as fixed asset investment, foreign direct investment, and higher education levels, etc. Therefore, the strategic direction of the development of the western region should focus on human capital investment, improve the market economy system, and strengthen exchanges and cooperation between regions in the future.
Diagnostic Study of Apparent Heat Sources and Moisture Sinks in the South China Sea and Its Adjacent Areas during the Onset of 1998 SCS Monsoon
Diagnostic Study of Apparent Heat Sources and Moisture Sinks in the South China Sea and its Adjacent Areas during the Onset of 1998 SCS Monsoon

Wang Shiyu,QianYongfu,
Wang Shiyu

大气科学进展 , 2000,
Abstract: The apparent heat sources (< Q1 >) and moisture sinks (< Q2 >) are calculated based on the reanalyzed data of the South China Sea Monsoon Experiment (SCSMEX) from May 1 to August 31, 1998. It is found that the formation and distribution of the atmospheric heat sources are important for the monsoon onset. The earlier onset of the SCS monsoon is the result of enduring atmospheric heating in the Indo-China Pe-ninsula and South China areas. The atmospheric heating firstly appears in the Indo-China Peninsula area and the sensible heat is the major one. The 30-50 day periodic oscillation of atmospheric heat sources be-tween the SCS area and the western Pacific warm pool has a reverse phase distribution before the middle of July and the low frequency oscillation of heat sources in SCS area has an obvious longitudinal propagation. The 30-50 day low frequency oscillation has vital modificatory effects on the summer monsoon evolution during 1998.
Persistent anomalous flows over the subtropical western Pacific in summer
Shiyu Zhuang,Liren Ji
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883574
Abstract: The distribution of global persistent anomaliesshows that the subtropical western Pacific is a key region with high-frequency occurrence of persistent anornalics. Analyscs of streamfunction anomalies, 013 anomalies etc. suggest that the convective heating related to Indian nlon.uwn might he responsible for the development of WPA. The results of numerical experiment by two linear bamtmpic rnodcls support the observation.
A Better Lower Bound Estimation of Brennan's Conjecture
Junyi Hu,Shiyu Chen
Mathematics , 2015,
Abstract: In this paper, we obtained an equivalent proposition of Brennan`s conjecture. And given two lower bound estimation of the conjecture one of them connected with Schwarzian derivative. The present study also verified the correctness of the conjecture in some special conditions.
The Generalization of Schottky Inequality and Its Applications
Shiyu Chen,Junyi Hu
Mathematics , 2015,
Abstract: This article used Bloch function to derive Schottky inequality, obtained its generalization by using elliptic integral deviation function and demonstrated its applications.
Bearing-Only Network Localization: Localizability, Sensitivity, and Distributed Protocols
Shiyu Zhao,Daniel Zelazo
Mathematics , 2015,
Abstract: This paper addresses self-localization of stationary sensor networks based on inter-neighbor bearings and anchor nodes whose locations are known. In our work, we formulate the bearing-only network localization problem as a linear least-squares problem and consider measurement models with and without errors. We provide necessary and sufficient conditions for the localizability of a network with both algebraic and rigidity theoretic interpretations. The proposed conditions fully describe the relationship between the localizability and the bearing rigidity properties of a network. We also analyze the sensitivity of the localization problem to constant measurement errors. Upper bounds for the localization error and the bearing errors that a network can tolerate are presented. Finally, we propose distributed protocols to globally localize bearing-only networks. All the results presented in the paper are applicable to networks in arbitrary dimensions. This work is validated with numerical simulations.
Bearing Rigidity and Almost Global Bearing-Only Formation Stabilization
Shiyu Zhao,Daniel Zelazo
Computer Science , 2014,
Abstract: A fundamental problem that the bearing rigidity theory studies is to determine when a framework can be uniquely determined up to a translation and a scaling factor by its inter-neighbor bearings. While many previous works focused on the bearing rigidity of two-dimensional frameworks, a first contribution of this paper is to extend these results to arbitrary dimensions. It is shown that a framework in an arbitrary dimension can be uniquely determined up to a translation and a scaling factor by the bearings if and only if the framework is infinitesimally bearing rigid. In this paper, the proposed bearing rigidity theory is further applied to the bearing-only formation stabilization problem where the target formation is defined by inter-neighbor bearings and the feedback control uses only bearing measurements. Nonlinear distributed bearing-only formation control laws are proposed for the cases with and without a global orientation. It is proved that the control laws can almost globally stabilize infinitesimally bearing rigid formations. Numerical simulations are provided to support the analysis.
Bearing-Based Formation Stabilization with Directed Interaction Topologies
Shiyu Zhao,Daniel Zelazo
Computer Science , 2015,
Abstract: This paper studies the problem of stabilizing target formations specified by inter-neighbor bearings with relative position measurements. While the undirected case has been studied in the existing works, this paper focuses on the case where the interaction topology is directed. It is shown that a linear distributed control law, which was proposed previously for undirected cases, can still be applied to the directed case. The formation stability in the directed case, however, relies on a new notion termed bearing persistence, which describes whether or not the directed underlying graph is persistent with the bearing rigidity of a formation. If a target formation is not bearing persistent, undesired equilibriums will appear and global formation stability cannot be guaranteed. The notion of bearing persistence is defined by the bearing Laplacian matrix and illustrated by simulation examples.
Bearing-Based Distributed Control and Estimation of Multi-Agent Systems
Shiyu Zhao,Daniel Zelazo
Computer Science , 2015,
Abstract: This paper studies the distributed control and estimation of multi-agent systems based on bearing information. In particular, we consider two problems: (i) the distributed control of bearing-constrained formations using relative position measurements and (ii) the distributed localization of sensor networks using bearing measurements. Both of the two problems are considered in arbitrary dimensional spaces. The analyses of the two problems rely on the recently developed bearing rigidity theory. We show that the two problems have the same mathematical formulation and can be solved by identical protocols. The proposed controller and estimator can globally solve the two problems without ambiguity. The results are supported with illustrative simulations.
Bearing-Based Formation Maneuvering
Shiyu Zhao,Daniel Zelazo
Computer Science , 2015,
Abstract: This paper studies the problem of multi-agent formation maneuver control where both of the centroid and scale of a formation are required to track given velocity references while maintaining the formation shape. Unlike the conventional approaches where the target formation is defined by inter-neighbor relative positions or distances, we propose a bearing-based approach where the target formation is defined by inter-neighbor bearings. Due to the invariance of the bearings, the bearing-based approach provides a natural solution to formation scale control. We assume the dynamics of each agent as a single integrator and propose a globally stable proportional-integral formation maneuver control law. It is shown that at least two leaders are required to collaborate in order to control the centroid and scale of the formation whereas the followers are not required to have access to any global information, such as the velocities of the leaders.
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