Albert Ting-pat So

Harmonics load signature recognition by wavelets transforms

Power quality has become an important concern both to the utilities and their customers. End user equipment is often more sensitive to disturbances that exist both on the supplying power system and within the customer facilities. Power quality embraces problems caused by harmonics, over or under-voltages, or supply discontinuities. Harmonics are caused by all sorts of nonlinear loads. In order to fully understand the problems caused by harmonics pollution, an effective means of identifying sources of power harmonics is important. The authors used fuzzy numbers for harmonics signature recognition. In this paper, the authors have made use of new developments in wavelets so that each type of current waveform polluted with power harmonics can well be represented by a normalised energy vector consisting of five elements. Furthermore, a mixture of harmonics load can also be represented by a corresponding vector. This paper describes the mathematics and algorithms for arriving at the vectors, forming a strong foundation for real-time harmonics signature recognition, in particular useful to the re-structuring of the whole electric power industry.

A new definition of intelligent buildings for Asia

Intelligent building (IB) is the future of our building industry. All new commercial buildings and probably luxurious domestic buildings are designed with a common goal – to become intelligent buildings. However, the official definition of IB has not yet been standardised around the world. In the USA, an IB is categorised by four basic elements, namely building structure, building systems, building services and building management. In Europe, the emphasis is on information technology and the genuine need of the user. In Singapore and China, it appears that the term “automation” has been dominating with a great emphasis on high technology. It is our view that a proper definition of IB should be based on users’ needs instead of the image of the building itself. We have therefore developed a new method for defining and specifying IBs. The requirements of users are categorised into eight key modules. All building systems and features are summarised in terms of tens of elements. Selected elements are assigned to a particular key area, i.e. module. Each type of building is then allocated certain key areas for detailed design. Once the areas have been chosen, the elements will automatically be assigned for the consultants to carry out detailed design works. This concept of definition has both advantages of comprehensiveness and flexibility, hoping that it will be useful for the developments of IBs not merely in Asia but also the whole world.

Internet based transmission substation monitoring

At the IEEE T&D Conference and exposition held in 1996 in Los Angeles, the authors presented the development of an on-line distributed information monitoring system for keeping track of the condition of HV equipment in transmission substations, such as status of each SF/sub 6/ circuit breaker (CB) together with other operational parameters, transformer temperature, capacitor bank unbalanced currents and auxiliaries including pumps, batteries and compressors etc. Each group of CBs is monitored by a standalone microcontroller where information can be exchanged between them on a local area network. A substation for the new Hong Kong International Airport was constructed revealing the shortfalls of the existing system because the substation had been too remote from the maintenance centres. The engineers in charge of transmission need to know not only the real-time status of equipment but also the security and fire safety of the substation. Furthermore, organisations involved in airport operation need to gain access to the information as well. Therefore, the original information system has been enhanced and extended by giving up the old idea of using modem based one-to-one communication and replacing it by an Internet based client server concept. The idea of remote vision for substation monitoring is also employed for integration with the Internet based system.

On the quantitative assessment of intelligent buildings

A paper on a new definition of intelligent buildings for Asia was published in Facilities in late 1999. This definition was later adopted by The Asian Institute of Intelligent Buildings as the official definition of intelligent buildings (IBs). The requirements of users were categorised into nine quality environment modules. Under each module, there are technologies and facilities supporting the operation of an IB. The beauty of that definition is that it can be further explored to arrive at a comprehensive and quantitative method of assessment for IBs, the Intelligent Building Index (IBI). Existing methods of assessment, in particular for environmentally friendly buildings in the USA and Hong Kong, have been reviewed. Shortcomings of the existing methodology and the room for improvement have been highlighted and discussed. The concept, mathematics and utilisation of the IBI are detailed in this paper.

Building automation systems on the Internet

Modern building systems, such as HVAC, lighting, life safety, security, vertical transportation and electrical power distribution, make use of modern direct digital control and communication technologies. Such an approach has initiated the use of the adjective ″smart″ when referring to buildings that are equipped with a significant portion of these new systems. Integrated building automation and management systems (BAS/BMS) have been developed for newly constructed commercial, domestic and industrial buildings. Building management staff can gain access to any building system through the BAS for the purpose of data monitoring and real‐time control inside the control room. With the advent of Internet technology, all critical data in a BAS can be transmitted to and from any authorized user around the world, who can then perform the same function of monitoring and control even when the user is thousands of miles away from the building as when the user is sitting in front of the control console inside the control room. Describes the development and features of the Internet‐based system using an air‐handling unit simulator as an illustrative example. Discusses details of the hardware and software of the Internet site.

A general doubly coprime factorization for descriptor systems

Doubly coprime factorization plays an important role in dealing with multivariable control problems using a factorization approach. In this study, based on an arbitrary and properly stabilizing controller, a general formula of doubly coprime factorization is obtained for use in descriptor systems. Detailed results have been derived on bridging the factorization approaches previously available in the literature.

LAN-based building maintenance and surveillance robot

The building and construction industry is the major industry of Hong Kong as in many developed countries around the world. After the commissioning of a high-rise building or a large estate, substantial manpower, both inside the management centre under a standby manner, as well as surveillance for security purposes around the whole building, is required for daily operation to ensure a quality environment for the occupants. If the surveillance job can be done by robots, the efficiency can be highly enhanced, resulting in a great saving of manpower and the improved safety of the management staff as a by-product. Furthermore, if the robot can retrieve commands from the building management system via a local area network (LAN), further savings in manpower can be achieved in terms of first-line fault attendance by human management staff. This paper describes the development of a robot prototype here in Hong Kong, which can handle some daily routine maintenance works and surveillance responsibilities. The hardware structure of the robot and its on-board devices are described. Real-time images captured by a camera on the robot with pan/tilt/zoom functions can be transmitted back to the central management office via a local area network. The interface between the robot and the building automation system (BAS) of the building is discussed. This is the first key achievement of this project with a strong implication on reducing the number of human staff to manage a modern building. Teleoperation of the robot via the Internet or intranet is also possible, which is the second achievement of this project. Finally, the robot can identify its physical position inside the building by a landmark recognition method based on standard CAD drawings, which is the third achievement of this project. The main goal of this paper is not the description of some groundbreaking technology in robotic development. It is mainly intended to convince building designers and managers to incorporate robotic systems when they are managing modern buildings to save manpower and improve efficiency.

Neural Network vs. Hedonic Price Model: Appraisal of High-Density Condominiums

In Hong Kong, high-density condominiums are routinely appraised by practitioners using the traditional comparative method. They collect a vast volume of transaction records, selecting suitable comparables from their data bank and then apply their professional judgment to adjust for any differences on factors such as view, orientation, area, floor height and market situation etc.

Survey on attitudes towards buildings in three Chinese cities: Hong Kong, Shanghai and Taipei

This paper presents the results of an attitudinal survey of residential and commercial building users from three Chinese cities – Hong Kong, Shanghai and Taipei. The results have been obtained from a much larger survey, primarily involving the living and working standards in the three cities. Apart from the descriptive statistics showing the preferences of the user, inferential statistics also showed significant differences among the attitudes of citizens living in the three cities. The results could give insights to designers and developers on the improvement of building standards.

A fuzzy expert system for contract decision making

A fuzzy reasoning model is constructed and its application to contract decision making in Hong Kong is illustrated. According to professional experience, six inputs are identified as essential factors determining contract choice. They are the scale of the project, the nature of the works to be carried out, the characteristics of the client, the time constraint, the source of materials for construction and the characteristics of the building design. These factors determine whether the contract to be chosen should be in the form of a simple quotation, a lump sum contract on drawings and specifications, a schedule of rates, a management contract, a lump sum contract in standard form without quantities or one with quantities. Ten decision rules are constructed based on expert opinions. Two practical cases are investigated and presented to illustrate how the method works.