Modeling of active heave compensation system of deep-sea mining based on dynamic vibration absorber and its H∞ robust control
The heave compensation system is vital for the deep-sea mining system undergoes excessive vibrations due to irregular wave loads for both normal operating and extreme conditions. To ensure its safety and operation efficiency, a novel active heave compensation system of deep-sea mining based on dynamic vibration absorber was proposed in this paper. The three-degree-of-freedom dynamic models of active heave compensation system based on dynamic vibration absorber in irregular wave are established. A H∞ Robust controller is designed for active heave compensation system by applying robust loop shaping control. The performance of H∞ robust controller and its robustness stability of the system are simulated and analyzed in frequency domain. The results show that the performance of the system in wave energy concentrated frequency domain of China's deep-sea mining field was improved by the concentrated weighting of acceleration output. And it also shows that the designed H∞ controller is perfect in system robustness stability against some parameter fluctuations of the system model. Therefore the designed active heave compensation system is practical to isolate the lift pipe and its support platform from the significant vibration of the ship motion induced by the irregular wave.
Optimum design of dynamic vibration absorbers of the continuous parameters system based on power flow
In accordance with a continuous parameters vibration system with dynamic vibration absorbers (DVAs), an equivalent admittance matrix and a correctional one are defined on the basis of the theories of structure mobility, and the process of dynamic analysis of the complex system is simplified. On the condition, those power flow inputted the system from vibration source, transmitted to major structure and absorbed by sub-structure are deduced. Furthermore, regarding the net power flow of main vibration system as the controlled object, discussed profoundly are the optimal design strategy of one or several absorbers controlled single or multiple models of the continuous parameters system, and it is validated by numerical calculus with computer. Finally, studied is the position of the vibration source influence to the transfer characteristic of power flow in vibration system and to the optimum parameters and control effect of absorbers.
The Area of Freedom, Security and Justice ten years on: Successes and future challenges under the Stockholm Programme. CEPS Paperbacks. June 2010
This book celebrates the tenth anniversary of the Area of Freedom, Security and Justice (AFSJ) by bringing together the views of key practitioners and policy-makers who have played an outstanding role in thinking about and shaping EU policies on freedom, security and justice. 
 
Ten years ago, the member states transferred competences to the EU for law and policy-making in the fields of immigration, asylum and border controls, and began the transfer process for criminal justice and policing. This decade of European cooperation on AFSJ policies has experienced very dynamic convergence, the enactment of a large body of European law and the setting-up of numerous EU agencies working in these domains. Such dynamism in policy-making has not been without challenges and vulnerabilities, however. As this collective volume shows, the main dilemmas that lie ahead relate to an effective (while more plural) institutional framework under the Treaty of Lisbon, stronger judicial scrutiny through a greater role for national courts and the Court of Justice in Luxembourg, better mechanisms for evaluating and monitoring the implementation of EU AFSJ law and a more solid fundamental rights strategy. The contributions in this volume address the progress achieved so far in these policy areas, identify the challenges for future European cooperation in the AFSJ and put forward possible paths for making more progress in the next generation of the EU’s AFSJ.