Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, t...Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, the ensuring of a safe sound pressure level is vital. In feedback systems, this is coupled with the stability of the closed control loop; stable controller design is thus essential. However, changes in the control path during run-time can cause the stable control system to become unstable, resulting in an overdrive of the speakers in the headphones. This paper proposes a method, which enables the real-time analysis of the current system state and if necessary stabilizes the closed loop while maintaining the active noise reduction. This is achieved by estimating and evaluating the open loop behavior with an adaptive filter and subsequently limiting the controller gain in respect to the stability margin.展开更多
This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promo...This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promotion Act （No. 2） B.E. 2550 of Ministry of Energy （Section--The Type or Size of Building Standards and Rules and Procedures, Building Design for Energy Conservation, Act B.E. 2552） are compared based on illumination standard for office building in term of energy consumption, return of investment and environmental impact. Firstly, the Type or Size of Building Standards and Rule and Procedures, Building Design for Energy Conservation, Act B.E. 2552 is reviewed and compared with the conventional designs of lighting system for office building. Next, the lifetime energy consumption of fluorescent lamp T5 with electronic ballast, fluorescent lamp T8 with standard ballast and fluorescent lamp T8 with electronic ballast are simulated using DIALux software program in three sizes office buildings. Then, the payback period and CO2 emission of lighting system for selected office building are simulated by various scenarios, which the analytical results show are the optimal lighting system for office building under the present situation. Finally, the optimal design of lighting system for designated office building in Thailand will be discussed with respect to the energy performance with environmental friendly.展开更多
文摘Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, the ensuring of a safe sound pressure level is vital. In feedback systems, this is coupled with the stability of the closed control loop; stable controller design is thus essential. However, changes in the control path during run-time can cause the stable control system to become unstable, resulting in an overdrive of the speakers in the headphones. This paper proposes a method, which enables the real-time analysis of the current system state and if necessary stabilizes the closed loop while maintaining the active noise reduction. This is achieved by estimating and evaluating the open loop behavior with an adaptive filter and subsequently limiting the controller gain in respect to the stability margin.
文摘This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promotion Act （No. 2） B.E. 2550 of Ministry of Energy （Section--The Type or Size of Building Standards and Rules and Procedures, Building Design for Energy Conservation, Act B.E. 2552） are compared based on illumination standard for office building in term of energy consumption, return of investment and environmental impact. Firstly, the Type or Size of Building Standards and Rule and Procedures, Building Design for Energy Conservation, Act B.E. 2552 is reviewed and compared with the conventional designs of lighting system for office building. Next, the lifetime energy consumption of fluorescent lamp T5 with electronic ballast, fluorescent lamp T8 with standard ballast and fluorescent lamp T8 with electronic ballast are simulated using DIALux software program in three sizes office buildings. Then, the payback period and CO2 emission of lighting system for selected office building are simulated by various scenarios, which the analytical results show are the optimal lighting system for office building under the present situation. Finally, the optimal design of lighting system for designated office building in Thailand will be discussed with respect to the energy performance with environmental friendly.
