PLI (professional liability insurance) is currently the main method used to control construction practice risk and is an important economic measure of construction industry governance. Few literatures have analyzed the sustainability of the liability insurance market. In particular, the research on the sustainability of the PLI market in the construction industry is still blank. The sustainability of the market can be identified with the equilibrium of the system over a certain period of time. From the perspective of cooperation benefits, this paper adopts evolutionary game theory (EGT) to analyze the evolutionary trends of stakeholders’ behaviors and their evolutionarily stable strategy (ESS) in the PLI market of the construction industry. A case study from the history of the US PLI market evolution over nearly 100 years is taken to illustrate the stakeholder game and interpret the market evolution path, and several typical stages of the development of the US PLI market are explored. Some factors that can cause a shift in equilibrium are found. The results show that the change in the legal environment will directly affect the payoffs of the stakeholders, cause market imbalance, and trigger crisis. These findings will help out the government to regulate the market in a timely manner by improving external factors, such as by building a sound credit system and ensuring the stability of the legal system. In an equilibrium state, competitive markets can eliminate individuals with high accident rates and companies with high operating costs. Moreover, these findings will also set a base for future researches to investigate the role of insurance market and legal environment in depth while providing the intensive critical factors towards sustainable construction industry.

The opinion spreading process can be modeled as the spread of an epidemic through a network, which assumes homogeneous relationships between individuals. However, positive and negative relationships in signed networks play different roles in the opinion spreading process, following the general rule that the same opinion will diffuse through friends, while the opposite opinion will likely emerge out of interactions between enemies. In order to explore opinion spreading behavior in signed networks, we proposed a simple opinion spreading model based on the susceptible-infected-recovered (SIR) epidemic model. Under the assumption of homogeneous mixing, we also analyzed the phase transition of opinion spreading in signed networks and found that critical spreading rates were closely related to the fraction of positive relationships in signed networks. Finally, we confirmed the correctness of our solutions using numerical simulations of the opinion spreading model in signed networks. Mod. Phys. Lett. B 2013.27. Downloaded from www.worldscientific.com by UNIVERSITY OF BRITISH COLUMBIA on 02/04/15. For personal use only. W. Li et al.occur are qualitatively similar to the mechanisms at play in the spread of biological diseases. 1 Traditional epidemic-type models, such as the susceptible-infectedsusceptible (SIS) model and the susceptible-infected-recovered (SIR) model, have been widely used to study the dynamics of social contagion in social networks that have homogeneous relationships, 2-5 which assumes that all links in a social network represent the reachable relationships between individuals. Under this assumption, an individual is equally likely to spread his or her opinion to any other member of the population through these links.However, recent studies have discovered that many realistic social networks exhibit signed relationships 6-9 which involve both positive (friendly) and negative (antagonistic) relationships. For example, the online rating site Epinions allows people to give positive or negative ratings to other raters. Similarly, in the online discussion site Slashdot, users can tag other users as "friends" or "foes". 10 These social networks can be described as signed networks because the relationship between each individual is identified as either positive or negative. In signed networks, nodes represent individuals and positive or negative links represent the positive or negative relationships between a pair of individuals. Much effort has been applied to studying signed networks, such as understanding structural balance, 11 detecting communities, 12 predicting negative and positive relationships 13,14 and exploring the differences between patterns of negative and positive interactions within multirelational networks that contain friendly and antagonistic relationships. 15 With respect to other online communication platforms that foster potentially emotional relationships, much research has focused on identifying the sign of a relationship (positive, negative, or neutral) using automated sentiment analysi...

The rise of blockchain has led to discussions on new governance models and the cooperation of multiple participants. Due to the cognitive defects of the blockchain protocol in terms of intelligent contracts and decentralized autonomous organizations (DAOs), it is often unclear as to how to make decisions about the evolution of blockchain applications. Many autonomous organizations, with the support of network technologies such as blockchain, blindly absorb members and expand the scale of the capital pool, while ignoring the cost advantage of traditional autonomous organizations based on social relations and mutual supervision to fight information asymmetry. In this context, this study analyzes the evolutionary trend of autonomous organizations and their members’ strategies under different policy environments. To this end, under the digital economy background, based on game theory, the evolutionary dynamics method, and the form of the mutual insurance organization, this study constructs an evolutionary dynamics model of distributed autonomous organizations. The results show that blind expansion without review aggravates the overall risk pool’s moral hazard, in the context of mutual insurance. Organizational strategies, such as risk pool splits, can effectively improve the risk pool’s operating performance and establish a benign competition elimination mechanism. Driven by cooperation efficiency and split supervision based on homogeneous clustering, the comprehensive application of the market elimination mechanism can effectively combat moral hazards, restrain the adverse effects of member flow, expand the living space of small- and medium-sized insurance organizations, curb the emergence of a large-scale monopoly risk pool, and improve market vitality. These conclusions and suggestions also apply to autonomous organizations based on social relations and mutual supervision. The results offer specific decision-making guidance and suggestions for the government, insurance companies, and risk management.

To reduce the noise caused by the flow of refrigerant during the defrost cycle and preserve the ambient sound level, this study concentrated on exploring the mechanism of noise generation in the gas–liquid separator based on visualization experiments. A transparent gas–liquid separator made of quartz glass, which was instead of the original one, was fabricated to observe the flow pattern of refrigerant in the gas–liquid separator, and the relationship between flow pattern and noise generation was investigated. The results showed that the noise is mainly generated during the defrost cycle. The sound power level has a drastic fluctuation when the liquid level of refrigerant in the gas–liquid separator is higher than the outlet of the evaporation tube during the defrost cycle. The reduction in noise is achieved by the redesigns that prevent the liquid level of refrigerant in the gas–liquid separator being higher than the outlet of the evaporation tube during the defrost cycle. Then, the noise level of original design and two redesigns was measured in a high precision semi-anechoicroom, respectively. The noise level of the refrigerator reduces from 30.2 dB(A) to 26.1 dB(A) and 24.4 dB(A) by increasing the volume of the gas–liquid separator for 87.1% and installing a ball valve respectively.