Frontier Technology

Information Technology

Information and communication technologies provide people with easy access to information that was difficult and time-consuming to obtain even a decade ago. Distributed systems, in particular, make it possible to collect, process and transmit vast amounts of information from geographically dispersed locations.

"The wireless sensor network, a type of distributed system, has been heralded as one of the most important technologies in the 21st century," said Professor V.O.K. Li of the Department of Electrical and Electronic Engineering and the convenor of the Information Technology research theme.

"Sensor networks are used in anything from military sensing and traffic surveillance to industrial automation and medical monitoring."

These networks are typically inexpensive and, as the name implies, wireless because sensors are fitted with onboard processors that collect data and carry out simple computations before transmission.

Researchers in the Faculty of Engineering are looking at how to make wireless sensor networks more efficient, both in terms of energy consumption and in performing operations.

Data transmission in wireless sensor networks (WSN)

A common way to collect the information produced by a sensor network is to programme the sensors to periodically transmit their readings to a base computer, but this can consume a lot of energy.

"We want to investigate a more energy-efficient approach by reducing the amount of information sent by sensors to the base," said Dr N. Mamoulis of the Department of Computer Science.

One approach might be to establish parameters on the information sent. Another is to have intermediaries consolidate information from sensors in a region and determine if it needs to be transmitted to the base for further study. Researchers will look at both options.

Computations in WSN

Wireless sensor networks can generate a lot of redundant information because sensors in the same vicinity may produce highly similar readings. HKU researchers plan to establish ways of evaluating correlations in information gathered by different sensors, categorise the energy needed for processing and for network transmission, and propose a protocol for wireless sensor networks with high energy efficiency.

Coverage in WSN

Coverage is a major issue in wireless sensor networks. When a large area has to be covered, many sensors have to be used. They require a lot of energy to keep running, so "sleep" modes are needed when a sensor is not required to perform a task.

Current approaches make this difficult because they assume there is a centralised server with global information. Sensors do not have access to that information and have to determine their schedules by communicating with their neighbours.

Researchers at HKU will develop a distributed protocol to help sensors determine their sleep and wake schedules.

Stereovision

Stereovision constructs 3-D scenes out of two or more images and enables computer systems to "see" their environment. Unfortunately, the technology has high computational requirements and correspondingly high energy demands.

"The demands are even higher in autonomous robots because they need to carry out additional computations to navigate around obstacles," said Dr H.K.H. So of the Department of Electrical and Electronic Engineering. "This limits their range because they are usually battery powered."

HKU researchers will investigate what trade-offs can be made to enable effective 3-D reconstructions with less energy. They will look at the whole system, from software to hardware, to optimise the energy performance.

Computer-supported collaborative learning

Collaborative online learning is becoming more popular, but how can teachers monitor the process and evaluate students’ performance? Text analysis is one approach, but this usually involves qualitative analyses, which is a problem for teachers.

"Qualitative analysis of textual data is not feasible for adoption by teachers who need to handle massive amounts of online data written by students on a day-to-day basis," said Professor N.W.Y. Law of the Faculty of Education and Director for the Centre of Information Technology in Education.

A more accessible form of automated text analysis is therefore being investigated jointly by the Faculty of Engineering and Faculty of Education. They will also look at the linguistic differences when analysing text from different socio-cultural settings (such as Chinese used by Hong Kong students and that used in mainland China) and between students of different age groups.