The real estate market is vital for national economic development, and it is of great significance to research an early warning method to identify an abnormal status of the real estate market. In this study, a real estate early warning system based on the PSO-LSSVR model was created to train and test the indicator data of Beijing from 2000 to 2020, and to predict the early warning indicator of the Beijing real estate market from 2021 to 2030. The results showed that the warning status of the Beijing real estate market went from a fluctuation status to a stable “Normal” status from 2000 to 2020, and the warning status is expected to be more stable under a “Normal” status in the next decade under the same political and economic environment. The PSO-LSSVR model was found to have accurate prediction ability and demonstrated generalization ability. Furthermore, the warning status of the Beijing real estate market was analyzed in combination with national historical policies. Based on the results, this paper proposes policy recommendations to promote the healthy and sustainable development of the real estate market.

With the continuous improvement of people 's living standards, people have put forward higher requirements for the safety and comfort of housing. Therefore, Inherent Defect Insurance, a financial method to guarantee the quality of construction projects, has also emerged. At present, China 's Inherent Defect Insurance has been gradually promoted, but its claim mechanism has not been analyzed and studied. From the perspective of construction engineering, this paper first makes a bibliometric analysis of the influencing factors of insurance claims that may be caused by construction engineering quality through VOSViewers, and the evaluation index system of inherent defects is constructed. Then, according to the influencing factors, the PSO-LSSVR model is adopted to fit the performance function of the inherent defects. Finally, based on the reliability design principle of engineering structure, the reliability index and failure probability of Inherent Defect Insurance are derived from the performance function of inherent defects. This paper also analyzes its application in insurance practice and determines the relationship between the number of insurance underwriting policies and the initial reserve of insurance at a certain risk level. This paper studies the probability of Inherent Defect Insurance by constructing the reliability model of inherent defect risks in construction quality, and analyzes the anti-risk ability of insurance companies from the perspective of claim, which provides scientific analysis methods and theoretical basis for the scientific decision-making of insurance companies.

China is striving to reach a peak in its carbon dioxide emissions by 2030 and achieve carbon neutrality by 2060. The accurate accounting of carbon emissions is important for achieving these dual carbon goals. An extensive literature review and field measurements were conducted to investigate the specific impact of population density on carbon emissions in large integrated healthcare organizations. This research uses VOSviewer to visualize the literature analysis. We determined that the flow of people is a key factor affecting carbon emissions during the operational phase of large-scale comprehensive medical institutions. Through field measurements, the relationship between the density of pedestrian flow and indoor environment measurements was derived, and the incremental equipment operating loads caused by changes in the indoor environment were analyzed. Using the carbon emission factor method advocated by the IPCC, a carbon emission accounting model based on different flow intervals was constructed, and the energy consumption of different equipment was fully considered according to its proportion. The validation results showed that the error between the calculated value and the actual values of the model was 3.07% (less than 5%), which has good validity. The model calculates the direct and indirect carbon emissions in the operational phase based on the population flow perspective, which can provide a reference for the energy-saving design and green operation of large-scale comprehensive medical institutions. The research will continue to focus on the population flow, and the accounting model will be further optimized through machine learning algorithms.

The system of inherent defect insurance is an important measure to serve the real economy through financial means and improve the quality of construction projects, which is the future development direction of Chinas construction industry. However, the related research is not perfect due to the short implementation of the insurance. This could bring risks to the promotion of insurance for companies. Insurance ruin theory is an important method in risk management theory, so adopting it to manage the risk inherent defect insurance from the perspective of insurance companies is vital. The research starts with the classic insurance ruin theory and determines the coefficient of premium collection from the perspective of claim settlement distribution expectations. Furthermore, the approximate distribution of claim settlement is deduced, and a comprehensive risk assessment model is constructed. Finally, based on the data of insurance actuarial practice in Shanghai, both the ruin probability of inherent defect insurance in each insuring term and its average required initial reserve are calculated, which provides the analyses on the risks and main subitems of inherent defect insurance as well as relevant suggestions. Finally, the sensitivity analysis is used to further analyse the risk of different insurance stages of IDI, and the relevant measures are proposed. The research can provide theoretical assistances for insurance companies to carry out effective risk management and provide model tools to make scientific decisions.

Leakage issues have received increasing attention as the most common and significant source of complaints in residential construction quality problems. In this study, based on the classification of residential construction leakage problems, 1947 water spray tests and 2333 water storage tests were conducted on 18 construction projects. An empirical analysis of 432 leakage cases was conducted to determine the loss law for a single leakage point as well as the loss laws for different grades of leakage problems. Through empirical analysis, it can be concluded that more than 90% of the leakage problems are third-level. To better understand the quantitative law of the residential construction leakage problem, a total loss law model was developed. Finally, the law of leakage loss in residential construction is summarized, and measures to reduce leakage loss in residential construction are proposed. This research can provide a theoretical basis and model tools for inherent defect insurance and help insurance companies control insurance risks and drive the promotion of inherent defect insurance.

Increasing attention has been drawn to the delamination of the external thermal insulation layer, which severely impacts the residents’ living quality and insurers’ claim risks. Therefore, the probability distribution of losses caused by external insulation layer delamination is investigated in this study through weather tests, considering that such delamination occurs due to a bond strength of zero, in order to provide scientific support for the inherent defect insurance (IDI). Using a thin-coat external thermal insulation system with expanded polystyrene (EPS) boards (500*500mm) as the test subject, weather tests were designed to simulate the monsoon climate in China. Bond strength testing was then performed to quantify the degradation level of the insulation layer. The results indicate that bond strength degradation and the initial bond strength under non-load conditions follows logistic distribution and Weibull distribution respectively, with 25% of the test blocks exhibiting Grade I damage. Additionally, the delamination failure probability is counted out 0.164 based on the structural reliability theory. Further analysis indicated that IDI claim frequencies can be approximated through a Poisson distribution using parameter λ, thereby establishing a quantitative model for insurers’ premium pricing and risk management. Moreover, the probabilistic patterns of insulation layer delamination were clarified by integrating experimental and theoretical methods, thereby not only addressing a critical knowledge gap in the IDI’s loss assessment for external insulation systems, but also directly enhancing the accuracy and reliability of construction quality insurance practices and IDI risk evaluation.