Second Order Necessary Conditions for Optimal Impulsive Control Problems

First and second order necessary conditions of optimality for an impulsive control problem are presented and derived. One of the main features of these results is that no a priori normality assumptions are required and they are informative for abnormal control processes as well. This feature follows from the fact that the conditions are derived from an extremal principle, which is proved for an abstract minimization problem with equality and inequality type constraints and constraints given by convex cone.Two simple examples illustrate the power of our result.     

Necessary Optimality Conditions for Optimal Control Problems with Intermediate Constraints

In this paper we study an optimal control problem with intermediate constraints. Our purpose is to obtain the first- and second-order necessary conditions for an optimal control problem with intermediate constraints.     

Chronological Calculus, High-Order Necessary Conditions for Optimality, and Perturbation Methods

The purpose of the article is to explain some aspects of the chronological calculus initiated by Revaz V. Gamkrelidze, and some of its applications. Chronological calculus is a high-power apparatus for investigating non-linear dynamical systems. Control systems described by ordinary differential equations, partial differential equations, and discrete-time equations are considered. High-order necessary conditions for optimality are given. In addition, two methods for constructing asymptotical expansions of solutions of ordinary differential equations with small parameter on the right-hand side are considered.     

On Sufficient Conditions for the Existence of a Fuchsian Equation with Prescribed Monodromy

Recent sufficient conditions for positive solvability of the Riemann–Hilbert problem, known and new, are presented.     

Analysis of Gaseous Flow Between Parallel Plates by Second‐ Order Velocity Slip and Temperature Jump Boundary Conditions

In this study the momentum and energy equations are solved to analyze the flow between two parallel plates by employing second‐order velocity slip and temperature jump conditions. The flow is considered to be laminar, incompressible, hydrodynamically/thermally fully developed, and steady state. In addition to the isoflux condition, viscous dissipation is included in the analysis. Closed form expressions for the temperature field and Nusselt number are obtained as a function of the Knudsen number and Brinkman number. The Nusselt number obtained by employing the second‐order model is found to be lower compared to the continuum value and agrees well with the other theoretical models. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21116     

Jump dynamics and volatility: Oil and the stock markets

Our study distinguishes itself from the prior studies within the oil and financial literature by not only examining the asymmetric effects of oil prices on stock returns, but also exploring the importance of structure changes in this dependency relationship. We retrieve daily data on S&P 500 and West Texas Intermediate (WTI) oil transactions covering the period from 1 January 1992 to 7 November 2006, and then transform the available data into daily returns. In contrast to the extant literature, in this study, consideration of expected, unexpected and negative unexpected oil price fluctuations is incorporated into the model of stock returns; we also focus on the ways in which oil price volatility, as opposed to general macroeconomic variables, can influence the stock market. We go on to implement the ARJI (Autoregressive Conditional Jump Intensity) model with structure changes, from which we conclude that high fluctuations in oil prices have asymmetric unexpected impacts on S&P 500 returns.     

影响工况内燃机车单月燃油消耗超标的因素分析及几点思考

针对2011年莱钢运输部部分机组在单月燃油消耗超标的现象,分析了造成工况内燃机车燃油消耗超标的主要原因及存在的难点问题,并针对性地提出了在工况内燃机车单月燃油消耗管理方面的对策。     

Refueling availability for alternative fuel vehicle markets: Sufficient urban station coverage

Alternative fuel vehicles can play an important role in addressing the challenges of climate change, energy security, urban air pollution and the continued growth in demand for transportation services. The successful commercialization of alternative fuels for vehicles is contingent upon a number of factors, including vehicle cost and performance. Among fuel infrastructure issues, adequate refueling availability is one of the most fundamental to successful commercialization. A commonly cited source reports 164,300 refueling stations in operation nationwide. However, from the perspective of refueling availability, this nationwide count tends to overstate the number of stations required to support the widespread deployment of alternative fuel vehicles. In terms of spatial distribution, the existing gasoline station networks in many urban areas are more than sufficient. We characterize a sufficient level of urban coverage based upon a subset of cities served by relatively low-density station networks, and estimate that some 51,000 urban stations would be required to provide this sufficient level of coverage to all major urban areas, 33 percent less than our estimate of total urban stations. This improved characterization will be useful for engineering, economic and policy analyses.     

Controls for microgrids with storage: Review,challenges, and research needs

The interest on microgrid has increased significantly triggered by the increasing demand of reliable, secure, efficient, clean, and sustainable electricity. More research and implementation of microgrid will be conducted in order to improve the maturity of microgrid technology. Among different aspects of microgrid, this paper focuses on controls of microgrid with energy storage. A comprehensive review on current control technology is given with a discussion on challenges of microgrid controls. Basic simulation results are also presented to enhance and support the analysis. Finally, research needs and roadmap for microgrid control are also described.     

Semiactive and Active Piezoelectric Vibration Controls for Switched Reluctance Machine

This paper presents two vibration control approaches using piezoelectric inserts applied to a switched reluctance machine (SRM) in order to reduce acoustic emission. The semiactive approach, called synchronized switch damping, consists of a particular voltage processing that increases the electromechanical energy conversion of the piezoelectric insert and leads to effective vibration energy dissipation. Piezoelectric inserts can also be considered as actuators: the active technique aims at imposing an adequate force in order to compensate the structure strain originated by the electromagnetic forces. These two techniques are compared on a single-phase structure mechanically similar to that of an SRM. Advantages and drawbacks depending on the chosen technique are then discussed.     

Energy-efficiency supervision systems for energy management in large public buildings: Necessary choice for China

Buildings are important contributors to total energy consumption accounting for around 30% of all energy consumed in China. Of this, around two-fifths are consumed within urban homes, one-fifth within public buildings, and two-fifths within rural area. Government office buildings and large-scale public buildings are the dominant energy consumers in cities but their consumption can be largely cut back through improving efficiency. At present, energy management in the large public sector is a particular priority in China. Firstly, this paper discusses how the large public building is defined, and then energy performance in large public buildings is studied. The paper also describes barriers to improving energy efficiency of large public buildings in China and examines the energy-efficiency policies and programs adopted in United States and European Union. The energy-efficiency supervision (EES) systems developed to improve operation and maintenance practices and promote energy efficiency in large public sector are described. The benefits of the EES systems are finally summarized.     

Stochastic models for sunshine duration and solar irradiation

Harmonic analysis of sunshine duration and solar irradiation measured at Sebele, Botswana is carried out. The data used consists of the monthly averages and the Julian-days averages of sunshine duration and solar irradiation sequences. This study involves splitting the time series into deterministic and stochastic components, and determining the proportion of the variance explained by each component. The stochastic component is analyzed for persistence using the Box and Jenkins technique. It is found that the stochastic component for monthly averages solar radiation series is best described by the second-order autoregressive Markov process, while that for Julian-days averages series has no memory.     

Stochastic techniques used for optimization in solar systems: A review

Nowadays, optimization of solar systems is used to reduce system total cost, increased life cycle savings and improving thermal efficiency. It is very demanding for optimal utilization of solar resources to meet the energy demands. Various optimization techniques either deterministic or stochastic are implemented to achieve this objective. The stochastic techniques generate better results as compared to deterministic in large search space in low computation time. The optimal set of design and operating parameters are means to produce maximum system performance. This study includes review of various stochastic optimization techniques implemented in solar energy systems for performance enhancement. Based on the results given by various investigators, an attempt has been made to compare the stochastic optimization techniques in terms of providing maximum system performance of different solar systems.     

Conditions and costs for renewables electricity grid connection: Examples in Europe

This paper compares conditions and costs for RES-E grid connection in selected European countries. These are Germany, the Netherlands, the United Kingdom, Sweden, Austria, Lithuania and Slovenia. Country specific case studies are presented for wind onshore and offshore, biomass and photovoltaic power systems, as based on literature reviews and stakeholder interviews. It is shown that, especially for wind offshore, the allocation of grid connection costs can form a significant barrier for the installation of new RES-E generation if the developer has to bear all such costs. If energy policy makers want to reduce the barriers for new large-scale RES-E deployment, then it is concluded that the grid connection costs should be covered by the respective grid operator. These costs may then be recouped by increasing consumer tariffs for the use of the grid.     

Hermes-Sussmann and ad-rank Conditions for Local Controllability

In this paper, we consider linear control systems on Lie groups and compare three different approaches to local controllability for these systems: Hermes-Sussmann conditions, Hermes condition, and ad-rank condition. We prove that the ad-rank condition can be deduced from the Hermes-Sussmann conditions. We also prove that the Hermes condition and the ad-rank condition are equivalent in case of systems with scalar control. As application, we provide a criterion for global controllability for restricted linear systems on the Heisenberg group.     

Stochastic Energy Source Access Management: Infrastructure-integrative modular plant for sustainable hydrogen-electric co-generation

The proposed Stochastic Energy Source Access Management (SESAM) comprises renewable energy sources coupled via a direct current bus with storage modules of complementary characteristics to achieve co-generation of hydrogen and electric power on a continuous duty basis. As complementary solutions, hydrogen energy storage to provide a large capacity and access-oriented storage based on magnetic, electric or kinetic energy with less capacity but a faster response time are considered. These are arranged to form a multi-level storage that can compensate stochastic fluctuations of power over diverse time scales. The developed energy management coordinates the operation of the diverse storage modules. In this context, the access-oriented storage acts as a shock absorber in order to shield fuel cells and electrolysers from fast fluctuations of wind power and load. The functions of the plant are validated through simulation using meteorological information obtained from the National Wind Technology Center in the USA. The plant is shown to provide the scheduled output of hydrogen and electric power. Since seen from its terminals SESAM behaves in the same way as a power plant with controlled fuel input, it can be readily integrated with given infrastructures.     

Easy Test for Stability of Laminated Beams with Structural Damping and Boundary Feedback Controls

In this paper, we consider the test problem of stability of the closed loop system composed of laminated beams with structural damping and boundary feedback controls. We give a simple test method of verifying the exponential stability of the closed loop system. The test system consists of the dominant parts of the closed loop system. Under certain condition, we show that if the test system is exponentially stable, then the closed loop system is also exponentially stable and the eigenvalues of the test system are asymptotic eigenvalues of the closed loop system. This research is supported by the Natural Science Foundation of China grant NSFC–60474017 and by the Liu Hui Center for Applied Mathematics, Nankai University & Tianjin University, P.R.China.     

Feedback-Invariant Optimal Control Theory and Differential Geometry, II. Jacobi Curves for Singular Extremals

This is the second article in the series that began in [4]. Jacobi curves were defined, computed, and studied in that paper for regular extremals of smooth control systems. Here we do the same for singular extremals. The last section contains a feedback classification and normal forms of generic single-input affine in control systems on a 3-dimensional manifold.