Modeling and control of complex dynamic systems: Applied mathematical aspects

The concept of complex dynamic systems arises in many varieties, including the areas of energy generation, storage and distribution, ecosystems, gene regulation and health delivery, safety and security systems, telecommunications, transportation networks, and the rapidly emerging research topics seeking to understand and analyse. Such systems are often concurrent and distributed, because they have to react to various kinds of events, signals, and conditions. They may be characterized by a system with uncertainties, time delays, stochastic perturbations, hybrid dynamics, distributed dynamics, chaotic dynamics, and a large number of algebraic loops. This special issue provides a platform for researchers to report their recent results on various mathematical methods and techniques for modelling and control of complex dynamic systems and identifying critical issues and challenges for future investigation in this field. This special issue amazingly attracted one-hundred-and eighteen submissions, and twenty-eight of them are selected through a rigorous review procedure

On the dynamics of the seasonal variation in the South China Sea throughflow transport

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 6854–6866, doi:10.1002/2013JC009367.The Luzon Strait transport (LST) of water mass from the Pacific Ocean to the South China Sea (SCS) varies significantly with seasons. The mechanisms for this large variability are still not well understood. The steady-state island rule, which is derived from a steady-state model, is not applicable to seasonal time scale variations in a large basin like the Pacific Ocean. In this paper, we will use a theoretical model that is based on the circulation integral around the Philippines. The model relates the LST variability to changes in the boundary currents along the east coast of the Philippines, including the North Equatorial Current (NEC) Bifurcation Latitude (NECBL), the transports of Kuroshio and Mindanao Currents (KC and MC), and to the local wind-stress forcing. Our result shows that a northward shift of the NECBL, a weakening of the KC or a strengthening of the MC would enhance the LST into the SCS. This relationship between the LST and the NEC-KC-MC is consistent with observations. The analytical result is tested by a set of idealized numerical simulations.This study has been supported by the National Science Foundation Grants (OCE 1028739, 0927017) (JY), and by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11010103), the project of Global Change and Air-Sea interaction (GASI-03-01-01-02), the Natural Science Foundation of China (40930844, 41222037), the National Basic Research Program of China (2013CB956202), Ministry of Education’s 111 Project (B07036) of China, Yong Science Foundation of Shandong (JQ201111) and Public science and technology research funds projects of ocean (201205018) (XL and DW).2014-06-1

Wind-driven exchanges between two basins : some topographic and latitudinal effects

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 4585–4599, doi:10.1002/jgrc.20333.This study examines some topographic effects on the island rule. We use an idealized and barotropic model to investigate the throughflow between a semienclosed marginal sea and a larger oceanic basin that are connected to each other by two channels. Two sets of experiments are conducted in parallel, one with a flat bottom and the other with a ridge between two basins. The model results show that the ridge affects the island rule considerably in several ways. First, the ridge blocks geostrophic contours and restricts a free exchange between two basins. The bottom pressure torque (or the form drag) is a dominant term in the balance of the depth-integrated vorticity budget and always results in a significant reduction of the throughflow transport. Second, horizontal friction promotes cross-isobathic flows and enhances the throughflow transport over the ridge. This is the opposite of what friction does in the original island rule in which a friction tends to reduce the throughflow transport. Third, the forcing region in the open ocean for the marginal-sea throughflow is shifted meridionally. Last, the topographic effect becomes small near the equator due to its dependence on f. This may explain why the PV barrier effect is smaller in the South China Sea than in the Japan/East Sea. The limitation of the barotropic model and some baroclinic effects will be discussed.This study has been supported by the National Science Foundation grants OCE 1028739, OCE 0927017, ARC 1107412, and ARC 0902090 (J.Y.), the WHOI Coastal Institute, and by the Ministry of Education’s 111 Project (B07036), National Basic Research Priorities Programmer (2013CB956202), Natural Science Foundation (41222037, 41221063), Natural Science Foundation of Shandong (JQ201111), and Public Welfare Scientific Research Project (201205018) of China (X.L. and D.W.).2014-03-1

Primary desmoplastic small round cell tumor of the duodenum

The desmoplastic small round cell tumor (DSRCT) is an extremely rare tumor that mainly affects adolescents and mostly involves the abdominal and pelvic peritoneum. A 14-year-old girl presented with intermittent epigastric pain; abdominal computed tomography and upper gastrointestinal barium X-ray revealed an 8 cm × 10 cm space-occupying mass in the duodenal region. The patient underwent pancreaticoduodenectomy and the final pathologic diagnosis was DSRCT. Although multi-agent systemic chemotherapy was given, the patient died of metastasis 8 months later. Early diagnosis and surgical treatment with adjuvant chemotherapy seems to be the best treatment choice for this disease

Time-Periodic Solutions of the Einstein's Field Equations II

In this paper, we construct several kinds of new time-periodic solutions of the vacuum Einstein's field equations whose Riemann curvature tensors vanish, keep finite or take the infinity at some points in these space-times, respectively. The singularities of these new time-periodic solutions are investigated and some new physical phenomena are found. The applications of these solutions in modern cosmology and general relativity can be expected.Comment: 10 pages, 1 figur