Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

Identification Signs and Prospects of Hydrate Gas

Gas hydrate is a kind of icy crystal body formed by water and natural gas in special conditions. The discovery of gas hydrates provides a wide sphere and a new way of thinking for finding clean and effective energy resources to replace increasingly exhausted traditional energy resources. Moreover, in our country there are a wide realm and bright prospect in the exploration of gas hydrate. This paper has summarized the progress on the study of gas hydrate. And based on the former research about gas hydrates, the integrative identification signs of gas hydrates were summarized in the aspects of seismic data, geophysical well logging, sedimentary and rock, geochemistry, topography and morphology. In the end, the author hopes it may provide some useful clues to the exploration of gas hydrate.

Integrated Hazard Identification(IHI):A Quick Accident Analysis and Quantification Method for Practitioners

There are many techniques for hazard identification and are divided into shortcut,standard and advanced techniques.Among these,HAZOP and What-If techniques are mostly engaged by practitioners in the chemical process industry.Both of these have certain advantages and limitations,i.e.,HAZOP is structured,and what-if covers broad range of scenarios.There is no hazard identification method,which can cover a broad range of scenarios and is structured in nature.For this purpose,a new technique namely integrated hazard identification(IHI)is proposed in this article that integrates HAZOP and What-If.The methodology is demonstrated via hazard identification study of urea synthesis section.Risk ranking is used to sort out the worst-case scenario.This worst-case scenario is further studied in detail for quantification that is performed using the ALOHA software.This quantification has assisted to detect ammonia concentrations in nearby control room and surroundings for worst-case scenario.It is revealed that if ammonia pump is not stopped within 10 minutes,concentration inside and outside the control room may reach to 384 ppm and 2630 ppm,compared to 1100 ppm(AEGL-3).Thus the proposed method would be easy,time saving and covers more details and would be handy for practicing engineers working in different chemical process industries.

A Low Power Non-Volatile LR-WPAN Baseband Processor with Wake-Up Identification Receiver

The paper proposes a low power non-volatile baseband processor with wake-up identification(WUI) receiver for LR-WPAN transceiver.It consists of WUI receiver,main receiver,transmitter,non-volatile memory(NVM) and power management module.The main receiver adopts a unified simplified synchronization method and channel codec with proactive Reed-Solomon Bypass technique,which increases the robustness and energy efficiency of receiver.The WUI receiver specifies the communication node and wakes up the transceiver to reduce average power consumption of the transceiver.The embedded NVM can backup/restore the states information of processor that avoids the loss of the state information caused by power failure and reduces the unnecessary power of repetitive computation when the processor is waked up from power down mode.The baseband processor is designed and verified on a FPGA board.The simulated power consumption of processor is 5.1uW for transmitting and 28.2μW for receiving.The WUI receiver technique reduces the average power consumption of transceiver remarkably.If the transceiver operates 30 seconds in every 15 minutes,the average power consumption of the transceiver can be reduced by two orders of magnitude.The NVM avoids the loss of the state information caused by power failure and energy waste caused by repetitive computation.