Hock M. Ng

We present the rationale, architecture, and implementation of an intelligent room, built upon a dense radio-based network of diverse electronic sensors, and interfaced with a cluster of dedicated computers. This room (an "iRoom") is capable of high-order tasks in event detection, analysis, processing, deduction, and inference. Initial focus has been to provide answers to the "Five W's" regarding a human visitor: Who, What, When, Where, and Why. The foundation technique that underpins this… Show more

We present the rationale, architecture, and implementation of an intelligent room, built upon a dense radio-based network of diverse electronic sensors, and interfaced with a cluster of dedicated computers. This room (an "iRoom") is capable of high-order tasks in event detection, analysis, processing, deduction, and inference. Initial focus has been to provide answers to the "Five W's" regarding a human visitor: Who, What, When, Where, and Why. The foundation technique that underpins this research is Sensor Fusion: the mathematical combination of disparate sensor reports and analyses into a rational result which is more accurate and more useful than its constituent parts. Show less

We describe a method of using a network of thermopile sensors distributed along the walls of a room to locate a person within the room. At any given time, a person would be in the view of at least one of the sensor nodes. An algorithm is used to calculate the distance of a person from each sensor node based on its temperature reading and locate the person based on a combination of the sensor readings from the distributed nodes. This method is immune to lighting changes and works even in total… Show more

We describe a method of using a network of thermopile sensors distributed along the walls of a room to locate a person within the room. At any given time, a person would be in the view of at least one of the sensor nodes. An algorithm is used to calculate the distance of a person from each sensor node based on its temperature reading and locate the person based on a combination of the sensor readings from the distributed nodes. This method is immune to lighting changes and works even in total darkness. Furthermore, this method of sensing can also detect events such as a person walking past the doorway to a room, lingering outside, and entering or leaving the room. Show less

GaN/Al(0.15)Ga(0.85)N multiple quantum wells (MQWs) have been grown by plasma-assisted molecular-beam epitaxy on R-plane sapphire substrates. Room-temperature photoluminescence studies were performed to compare the optical properties of the MQWs grown on (0001) and (10-12) Al2O3 substrates. The peak transition energy, as a function of well width for the (11-20) MQWs, followed the trend for rectangular potential profiles indicating the absence of built-in electrostatic fields. In comparison, the… Show more

GaN/Al(0.15)Ga(0.85)N multiple quantum wells (MQWs) have been grown by plasma-assisted molecular-beam epitaxy on R-plane sapphire substrates. Room-temperature photoluminescence studies were performed to compare the optical properties of the MQWs grown on (0001) and (10-12) Al2O3 substrates. The peak transition energy, as a function of well width for the (11-20) MQWs, followed the trend for rectangular potential profiles indicating the absence of built-in electrostatic fields. In comparison, the peak transition energies for the (0001) MQWs showed a significant redshift due to the quantum-confined Stark effect, consistent with a built-in field value of 750 kV/cm. In addition, the photoluminescence intensity was 20 to 30 times higher for the (11-20) MQWs compared to the (0001) MQWs. Show less