Advanced property valuation techniques and valuation accuracy: Deciphering the artificial neural network technique

Property valuation end-users generally rely on property value opinion provided by valuers in making informed real estate investment decisions. However, the inaccuracy of valuation estimates could be attributed to the adoption of inappropriate property valuation methods and such inaccurate estimates could mislead real estate investors and stakeholders. This could result in individual loss and national loss due to the importance of the real estate sector to the national economy. Therefore, this study aims to examine the application of advanced property valuation techniques with special emphasis on the artificial neural network (ANN) technique in estimating accurate property values. A detailed review of the literature on issues involved in property valuation was conducted. The issues presented in this paper include the origin of ANN, its strength and weaknesses in comparison with other valuation approaches, its application both in theory and in practice, requirements for application in property valuation, valuers' response to its adoption, amongst others. It was found that the ANN technique could produce on the average accurate and reliable estimates but has not been widely adopted in practice. Thereafter, the challenges ahead in bridging the gap between theory and practice of the application of artificial intelligence (AI) techniques were discussed. In addition, the strategies of facilitating this paradigm shift to achieve a global sustainable property valuation practice are presented in this paper

Critical Factors Affecting the Safety Communication of Ethnic Minority Construction Workers

Ethnic minority workers (EMWs) or migrant workers continue to be confronted with communication problems, which can have serious effects on safety outcomes. This study aims to help improve construction industry EMW safety communication by uncovering and analyzing the criticality, underlying constructs, and explanatory power of the influencing factors involved. A mixed research design was employed by combining a literature review, semistructured interviews, and a questionnaire survey. Following the identification of an initial set of safety communication factors (SCFs) and a questionnaire designed and administered to EMWs in the Hong Kong and Australian construction industry, a total of 134 valid responses were analyzed through mean scoring, factor analysis, and importance-explanation analysis. Eighteen critical EMW SCFs are identified and categorized into three groups of worker-related SCFs, manager-related SCFs, and organization-related SCFs. A set of 36 SCFs identified cannot only be used to examine the relative importance of EMW SCFs, but can also be adopted to capture the critical SCFs for both local and ethnic minority construction workers in other countries. Narrowing a wide range of SCFs for EMWs provides stakeholders with the insights needed to the key contributory factors of safety communication, which in turn has a positive impact on safety performance. Despite this study being conducted in Hong Kong and Australia, its findings can also be used as a reference for other countries where EMWs are employed (e.g., the US, the UK, Canada, the Middle East, Malaysia, Singapore, and South Africa). Practical Applications Safety communication is a major safety challenge for EMWs and effective safety communication leads to improved safety performance and decreased injuries and fatalities. This research provides extra information on the key issues of safety communication that associated stakeholders need to address for EMWs to help them understand and mitigate the main safety communication barriers. This study suggests that apart from some measures (e.g., language courses, understandable safety training and safety materials, and bilingual translators) that have been taken for improving EMW safety communication in many countries, governments and employers are recommended to adopt multifaceted strategies manipulating worker-, manager-, and organization-related SCFs that would be more effective than a single measure. The critical roles of managers and organizations in promoting EMW safety communication are also emphasized in this study. Future efforts to improve or develop programs or interventions for EMW safety communication can benefit from this study by referring to the critical SCFs to include each aspect of safety communication. Furthermore, the identified critical SCFs will also help industry practitioners diagnose deficiencies in EMW safety management practices.</p

Results from MAGIC's first observation cycle on galactic sources

During its Cycle I, the MAGIC telescope targeted about 250 hours several galactic sources sought to be, or detected previously by other experiments in the same energy domain, gamma-ray emitters. This paper reviews some results of such MAGIC observations covering, among others, supernova remnants, the Galactic Center and microquasars. We will concentrate on the recent discovery at very high energy gamma-rays of the microquasar LS I +61 303.Comment: 6 pages, 8 figures. Prepared for "The Multi-messenger Approach to High-energy Gamma-ray Sources", Barcelona (Spain) 4-7 July 200

High-energy gamma-ray emission from the inner jet of LS I+61 303: the hadronic contribution revisited

LS I+61 303 has been detected by the Cherenkov telescope MAGIC at very high energies, presenting a variable flux along the orbital motion with a maximum clearly separated from the periastron passage. In the light of the new observational constraints, we revisit the discussion of the production of high-energy gamma rays from particle interactions in the inner jet of this system. The hadronic contribution could represent a major fraction of the TeV emission detected from this source. The spectral energy distribution resulting from p-p interactions is recalculated. Opacity effects introduced by the photon fields of the primary star and the stellar decretion disk are shown to be essential in shaping the high-energy gamma-ray light curve at energies close to 200 GeV. We also present results of Monte Carlo simulations of the electromagnetic cascades developed very close to the periastron passage. We conclude that a hadronic microquasar model for the gamma-ray emission in LS I +61 303 can reproduce the main features of its observed high-energy gamma-ray flux.Comment: 6 pages. Sligth improvements made. Accepted version by Astrophysics and Space Scienc

Novel vertical directional coupler made by field-assisted ion-exchanged slab waveguides in glass

Novel vertical directional couplers, consisting of graded-index planar waveguides, were realised by field-assisted K+-ion exchange in glass. Normal mode measurements of the coupling length are compared to results based on numerical simulations of the diffusion equation and the beam propagation method

Critical behavior of the planar magnet model in three dimensions

We use a hybrid Monte Carlo algorithm in which a single-cluster update is combined with the over-relaxation and Metropolis spin re-orientation algorithm. Periodic boundary conditions were applied in all directions. We have calculated the fourth-order cumulant in finite size lattices using the single-histogram re-weighting method. Using finite-size scaling theory, we obtained the critical temperature which is very different from that of the usual XY model. At the critical temperature, we calculated the susceptibility and the magnetization on lattices of size up to $42^3$. Using finite-size scaling theory we accurately determine the critical exponents of the model and find that $\nu$=0.670(7), $\gamma/\nu$=1.9696(37), and $\beta/\nu$=0.515(2). Thus, we conclude that the model belongs to the same universality class with the XY model, as expected.Comment: 11 pages, 5 figure

Developing a multidimensional performance measurement framework for international construction joint ventures (ICJVs): the perspective of Ghana-hosted ICJVs' practitioners

Purpose: International construction joint ventures (ICJVs) will fully realize their potential for success and effectively monitor performance when an adequate and suitable performance benchmark is established. However, existing studies fall short of adequately providing a mutually acceptable benchmark for assessing the performance of ICJVs. This study aims to develop an adequate and suitable performance measurement framework for ICJVs. Design/methodology/approach: A twofold structured questionnaire survey, supplemented by semi-structured interviews, was used to collect data from the practitioners of ICJVs hosted in the developing country of Ghana. The data were analyzed by using descriptive statistics, confirmatory factor analysis (CFA) and a hybrid-fuzzy logic approach. Findings: A list of 30 performance indicators (PIs), defined by project performance, perceived satisfaction, company/partner performance, socio-environmental performance and performance of ICJV management, was validated and proved to be significant. Only 22 out of the 30 PIs, focusing on project efficiency, societal improvement and organizational goals are realized by the ICJV practitioners. Further, suitable determinants and viable quantitative ranges for measuring each PI are established to prevent different interpretations of the meanings of PIs and objectively express the level of success in quantitative terms. The results call for further investigation of the convergence between the practice of and research into some PIs (e.g. socio-environmental performance) and a range of different performance levels (PLs) in a more scientific manner. Practical implications: This study not only advances the knowledge base and practice of performance measurement in ICJVs but could also assist stakeholders and decision-makers to assess, compare and monitor the performance of different ICJV projects on common grounds objectively. Originality/value: This study not only comprehensively assessed PIs – what to measure – but also systematically determined suitable determinants – how to measure – for each PI

Development of a building sustainability assessment method (BSAM) for developing countries in sub-Saharan Africa

The consideration of the regional context in the development of green building rating systems is well established in the extant literature, and this informs the development of a sustainability assessment method for sub-Saharan Africa. Hence, a multi-expert consultation method was carried out in Nigeria which is the largest economy in the region. This was performed via a structured questionnaire survey and interview approaches to identify the key sustainability assessment criteria, assign score-weights to the various criteria, and establish the certification grading system of buildings. The developed Building Sustainability Assessment Method (BSAM) scheme and its weighted criteria were validated using two existing building case studies. The established BSAM scheme was compared to six widely used green building rating systems. The comparative analysis reveals that the score-weights and priorities of the BSAM scheme were remarkably different from the existing rating systems. The study findings also show the increasing focus on the indoor environmental quality and energy criteria by all the rating systems. The developed BSAM scheme, meanwhile, has adequately considered the three main pillars of sustainable development unlike the existing green rating tools. Hence, it is expected for the proposed BSAM scheme to promote greener buildings and enhance sustainable urban development in the region

Barriers to the Integration of BIM and Sustainability Practices in Construction Projects: A Delphi Survey of International Experts

The built environment faces numerous challenges in its quest to be more productive and sustainable, and to the adoption of a smart and creative process of carrying out the various operations. This study aims to investigate the profound barriers faced by construction stakeholders in their attempts to integrate BIM and sustainability practices in the construction processes. A two-round Delphi survey formed the basis of aggregating consensus among the expert panel based on a set of 38 factors derived via content analysis of previous research studies. Descriptive and inferential tests were employed for data analysis, and the results validated using the interrater agreement analysis. The three key barriers by descending order of significance are industry's resistance to change from traditional working practices, an extended period of adapting to innovative technologies and the lack of understanding of the processes and workflows required for BIM and sustainability. Deductions were also made based on the comparative analysis of the expert groups. The findings will advance the implementation of BIM and sustainability practices in construction projects and enable project stakeholders to focus on addressing the critical challenges discussed in this study