The 1990 World Values Survey demonstrated that industrialization promotes a shift from traditional to secular-rational values. Drawing data from a sample survey of 2,350 respondents in Shanghai, this study examines the impact of social change on people's values in China. Specifically, we are interested in (1) are there significant differences in values between different generations in China? (2) Do younger generations tend to have more modern values? (3) What are the main factors that affect the differences? The results show that the younger generations in China have already shifted from traditional values to modern values in a recent social transformation process. In addition, the younger generations tend to be more secular. They are more likely to regard self-development as the most important thing in life rather than making contributions to the country and society. Further, the younger generations are more individualistic than the old generations. They are more likely to live according to their own lifestyles regardless of what others think. Thus, they are less likely to follow the traditional collective ideology. Overall, the study shows significant generational gaps in value orientations in China.

A transient-based leakage detection method using a matched-field processing (MFP) scheme is formulated and applied. It is found to be efficient, robust, accurate, and provides a unique solution. Its inherent efficiency stems from the fact that the MFP method decouples the search for the leak location and the leak size. Its robustness is demonstrated by showing that the MFP method is able to estimate the location and size of leak in the presence of (1) noise even for signal-to-noise ratio (SNR) as low as SNR ¼ −3 dB, and (2) uncertainty in the fluid-pipe system wave speed. Another positive attribute of the MFP method is that it is able to use all available frequencies, rather than just resonant frequencies, and does not need to identify resonant frequencies. As a result, the MFP method provides precise localization estimates even in noisy environments. It is also shown that a unique identification is achieved by the MFP method provided that the pressure signal is measured at two locations along the pipe. For the case of multiple leaks, MFP identifies each of the leaks provided that the distance between the leaks is of the same order or larger than the shortest probing half-wavelength.

Stability is a fundamental design property of inventory systems. However, the often exploited linearity assumptions in the current literature create a major gap between theory and practice. In this paper the stability of a constrained production and inventory system with a Forbidden Returns constraint (that is, a non-negative order rate) is studied via a piecewise linear model, an eigenvalue analysis and a simulation investigation. The APVIOBPCS (Automatic Pipeline, Variable Inventory and Order Based Production Control System) and EPVIOBPCS (Estimated Pipeline, Variable Inventory and Order Based Production Control System) replenishment policies are adopted. Surprisingly, all kinds of non-linear dynamical behaviours of systems can be observed in these simple models. Exact expressions of the asymptotic stability boundaries and Lyapunovian stability boundaries are derived when actual and perceived transportation lead-time is 1 and 2 periods long respectively. Asymptotically stable regions in the non-linear Forbidden Return systems are identical to the stable regions in its unconstrained counterpart. However, regions of bounded fluctuations that continue forever, including both periodicity and chaos, exist in the parametrical plane outside the asymptotically stable region. Simulation shows a complex and delicate structure in these regions. The results suggest that accurate lead-time information is essential to eliminate inventory drift and instability and that ordering policies have to be designed properly in accordance with the actual lead-time to avoid these fluctuations and divergence. Keywords: Inventory; logistics; system dynamics; complexity theory The introduction and motivationOne of the main objectives when designing an inventory system is to maintain its stability and robustness in the face of exterior disturbances. Since the introduction of control theory and system dynamics approaches to the field of inventory control (Simon, 1952;Forrester, 1961), many works have studied this problem. However, the significance of results obtained are frequently limited by both the uncertainty and complexity of the system structure. Often omitted factors in inventory system design include saturation (logistics constraints) and mis-specified delays (lead-times).In previous supply chain stability studies (Riddalls and Bennett, 2002;Nagatani and Helbing, 2004;Warburton et al., 2004;Disney, 2008), linear inventory system models are usually adopted. Linearity assumptions include infinite capacity, ignoring inventory limitations and return restrictions. This has greatly limited the applicability of published results, and has failed to explain many business phenomena (Riddalls et al., 2000). For instance, to maintain linearity of the commonly investigated IOBPCS (Inventory and Order Based Production Control System) models, order rates are permitted to take negative values. This means that all participants in a supply chain are allowed to return excess product freely. Specifically, a negative order rate value leads to a ...

Most pipes in current urban water distribution systems have been laid down underground for several decades (AWWA, 2012;Che et al., 2021). These underground pipes are aging and fraught with leaks, which poses a tremendous challenge to water and energy savings as well as drinking water security (

We present an analytical investigation of the intrinsic oscillations in a nonlinear inventory system where excessive inventory cannot be returned to the supplier. Mathematically this is captured by a non-negative constraint on the replenishment order. By studying the eigenvalues of the characteristic matrices of the system, the criteria for different types of dynamic behaviour (including convergence, periodicity, quasi-periodicity, chaos, and divergence) are derived. The upper and lower bounds of the order and inventory oscillations are found via a time-domain analysis. Our results are verified by bifurcation diagrams. We find that the closer the replenishment rule feedback parameters are to the convergence area, the milder the intrinsic oscillation of the system.