Jack Chin Pang Cheng

Bio: Jack Chin Pang Cheng is an academic researcher from Hong Kong University of Science and Technology. The author has contributed to research in topics: Building information modeling & Precast concrete. The author has an hindex of 38, co-authored 198 publications receiving 4922 citations. Previous affiliations of Jack Chin Pang Cheng include City University of Hong Kong & East China Normal University.

Comparative environmental evaluation of aggregate production from recycled waste materials and virgin sources by LCA

Abstract: The management of construction and demolition (C&D) waste and waste glass is a serious concern in Hong Kong, as well as other countries due to their non-combustible and non-putrescible nature, and the running out of disposal outlets. However, mineral wastes derived from C&D activities and waste glass are considered to have potential to be re-used as construction materials, especially as aggregates. In addition, Hong Kong urgently needs alternative and sustainable sources of aggregate, as the local quarry sites for aggregate production are expected to be exhausted soon. Many experimental studies have demonstrated that recycled aggregates from C&D waste and waste glass can be potentially recycled for various engineering applications in Hong Kong, but no study has yet attempted to assess the sustainability by lifecycle assessment (LCA) techniques. In order to increase the environmental awareness in the construction industry, assessment of the environmental performance of construction materials by LCA is therefore needed. The present study was conducted to assess and compare the environmental consequences of recycled aggregates production from C&D waste and waste glass, and natural aggregate production from virgin materials by LCA by using case specific and first hand data. The results reveal that compared with natural coarse aggregates, recycled coarse aggregates produced from C&D waste reduce 65% greenhouse gases (GHGs) emission with a saving of 58% non-renewable energy consumption. Similar environmental benefits are observed for producing recycled fine aggregates from C&D waste. In addition, compared with the production of natural fine aggregates from river sand, producing recycled fine aggregates from waste glass saves 54% energy consumption and reduces 61% GHGs, and 46% SO2 eq emissions. According to the IMPACT 2002+ Method, significant health, resource, climate change and ecosystem damages can be saved in producing recycled aggregates from both waste materials compared to producing and importing aggregates from virgin sources. This is the first ever LCA study on producing recycled aggregates from waste glass. Therefore, it can be concluded that substantial net environmental benefits can be realized for producing recycled aggregates from C&D waste and waste glass. The results can provide a guidance to maximize C&D waste and waste glass recycling, resourceful treatment of wastes and conserve natural resources.

A state-of-the-art review on the integration of Building Information Modeling (BIM) and Geographic Information System (GIS)

Abstract: The integration of Building Information Modeling (BIM) and Geographic Information System (GIS) has been identified as a promising but challenging topic to transform information towards the generation of knowledge and intelligence. Achievement of integrating these two concepts and enabling technologies will have a significant impact on solving problems in the civil, building and infrastructure sectors. However, since GIS and BIM were originally developed for different purposes, numerous challenges are being encountered for the integration. To better understand these two different domains, this paper reviews the development and dissimilarities of GIS and BIM, the existing integration methods, and investigates their potential in various applications. This study shows that the integration methods are developed for various reasons and aim to solve different problems. The parameters influencing the choice can be summarized and named as “EEEF” criteria: effectiveness, extensibility, effort, and flexibility. Compared with other methods, semantic web technologies provide a promising and generalized integration solution. However, the biggest challenges of this method are the large efforts required at early stage and the isolated development of ontologies within one particular domain. The isolation problem also applies to other methods. Therefore, openness is the key of the success of BIM and GIS integration.

From RSSI to CSI: Indoor Localization via Channel Response, A survey on indoor localization using PHY-layer information

Abstract: The spatial features of emitted wireless signals are the basis of location distinction and determination for wireless indoor localization. Available in mainstream wireless signal measurements, the Received Signal Strength Indicator (RSSI) has been adopted in vast indoor localization systems. However, it suffers from dramatic performance degradation in complex situations due to multipath fading and temporal dynamics. Break-through techniques resort to finer-grained wireless channel measurement than RSSI. Different from RSSI, the PHY layer power feature, channel response, is able to discriminate multipath characteristics, and thus holds the potential for the convergence of accurate and pervasive indoor localization. Channel State Information (CSI, reflecting channel response in 802.11 a/g/n) has attracted many research efforts and some pioneer works have demonstrated submeter or even centimeter-level accuracy. In this article, we survey this new trend of channel response in localization. The differences between CSI and RSSI are highlighted with respect to network layering, time resolution, frequency resolution, stability, and accessibility. Furthermore, we investigate a large body of recent works and classify them overall into three categories according to how to use CSI. For each category, we emphasize the basic principles and address future directions of research in this new and largely open area.