Towards a resilient networked service system

Large service systems today are of highly network structures. In this thesis, these large service systems are called networked service systems. The network nature of these systems has no doubt brought mass customized services but has also created challenges in the management of their safety. The safety of service systems is an important issue due to their critical influences on the functioning of society. Traditional safety engineering methods focus on maintaining service systems in a safe state, in particular aiming to maintain systems to be reliable and robust. However, resilience cannot be absent from safety out of many recent disasters that occur in society. The goal of this thesis is to improve the resilience of networked service systems. Four major works have been performed to achieve this goal. First, a unified definition of service systems was proposed and its relationship to other system concepts was unfolded. Upon the new definition, a domain model of service systems was established by a FCBPSS framework, followed by developing a computational model. Second, a definition of resilience for service systems was proposed, based on which the relationship among three safety properties (i.e., reliability, robustness and resilience) was clarified, followed by developing a framework for resilience analysis. Third, a methodology of resilience measurement for service systems was proposed by four measurement axioms along with corresponding mathematical models. The methodology focused on the potential ability of a service system to create optimal rebalancing solutions. Two typical service systems, transportation system and enterprise information system, were employed to validate the methodology. Fourth, a methodology of enhancing resilience for service systems was proposed by integrating three types of reconfigurations of systems, namely design, planning and management, along with the corresponding mathematical model. This methodology was validated by an example of transportation system. Several conclusions can be drawn from the work above: (1) a service system has a unique characteristic that it meets humans' demand directly, and its safety relies on the balance between the supplies and demands; (2) different from reliability and robustness, the resilience of a service system focuses on the rebalancing ability from imbalanced situations; (3) it makes sense to measure the resilience of a service system only for a particular imbalanced situation and based on evaluation of rebalancing solutions; and (4) integration of design, planning and management is an effective approach for improvement of the resilience for a service system. The contributions of this thesis can be summarized. Scientifically, this thesis work has improved our understanding of service systems and their resilience property; furthermore, this work has advanced the state of knowledge of safety science in particular having successfully responded to two questions: is a service system safe and how to make a service system safer? Technologically or methodologically, the work has advanced the knowledge for modeling and optimization of networked service systems in particular with multiple layer models along with the algorithms for integrated decision making on design, planning, and management

Research on the Achievements, Experience and Innovation Path of China’s Green Sharing Economy in the New Era

The Green Sharing Economy represents a novel economic paradigm emergent under the auspices of global technological revolutions and industrial transformation. This paradigm facilitates optimal resource allocation, establishing precise alignments between “demand pools” and “supply pools.” It concurrently enhances ecological environments, creating a harmonious interplay between lush landscapes and prosperous economies, while expanding employment opportunities, and fostering synergistic developments in mass entrepreneurship and innovation. Within the framework of the New Era, China’s Green Sharing Economy has experienced rapid ascension. This growth fundamentally stems from the continuous refinement of top-level designs by the Chinese government, guiding high-quality development in the Green Sharing Economy. Initiatives include the advancement of administrative streamlining and decentralization, creating a conducive business environment; the acceleration of information technology development, eliminating connectivity barriers; and significant investment in digital talent cultivation, providing the necessary human capital foundation. At this historical juncture, it is imperative to expedite the construction of a trust system for the Green Sharing Economy, continuously optimize its platform technology, constantly improve its regulatory framework, and actively expand its global market presence

Observation of Ultrahigh Mobility Surface States in a Topological Crystalline Insulator by Infrared Spectroscopy

Topological crystalline insulators (TCIs) possess metallic surface states protected by crystalline symmetry, which are a versatile platform for exploring topological phenomena and potential applications. However, progress in this field has been hindered by the challenge to probe optical and transport properties of the surface states owing to the presence of bulk carriers. Here we report infrared (IR) reflectance measurements of a TCI, (001) oriented $Pb_{1-x}Sn_{x}Se$ in zero and high magnetic fields. We demonstrate that the far-IR conductivity is unexpectedly dominated by the surface states as a result of their unique band structure and the consequent small IR penetration depth. Moreover, our experiments yield a surface mobility of 40000 $cm^{2}/(Vs)$, which is one of the highest reported values in topological materials, suggesting the viability of surface-dominated conduction in thin TCI crystals. These findings pave the way for exploring many exotic transport and optical phenomena and applications predicted for TCIs

An MPCC Formulation and Its Smooth Solution Algorithm for Continuous Network Design Problem

Continuous network design problem (CNDP) is searching for a transportation network configuration to minimize the sum of the total system travel time and the investment cost of link capacity expansions by considering that the travellers follow a traditional Wardrop user equilibrium (UE) to choose their routes. In this paper, the CNDP model can be formulated as mathematical programs with complementarity constraints (MPCC) by describing UE as a non-linear complementarity problem (NCP). To address the difficulty resulting from complementarity constraints in MPCC, they are substituted by the Fischer-Burmeister (FB) function, which can be smoothed by the introduction of the smoothing parameter. Therefore, the MPCC can be transformed into a well-behaved non-linear program (NLP) by replacing the complementarity constraints with a smooth equation. Consequently, the solver such as LINDOGLOBAL in GAMS can be used to solve the smooth approximate NLP to obtain the solution to MPCC for modelling CNDP. The numerical experiments on the example from the literature demonstrate that the proposed algorithm is feasible.</p

Foreign Direct Investment Inequality (FDI) and Convergence of Growth: Evidence from Yangtze River Delta

The Yangtze River Delta (YRD) Economic Circle has experienced a long period of development. From the original Shanghai Economic Zone in 1983, altogether 10 cities encompassing Suzhou, Wuxi, Changzhou, Nantong and Hangzhou, Jiaxing, Huzhou, Ningbo and Shaoxing surrounding the Shanghai Core, to the final stage in 2003 when the latest leaguer, Taizhou of Zhejiang Province joined the family, the YRD has been experiencing a long time of expansion. Focusing on the aggregation, see Table 1, the YRD attracted almost half the FDI in the nationwide scale, over 1/3 export and import, around 6 percent of the fixed investment and produced nearly 1/5 of the GDP. We should say this was, and is a miracle in the river of regional economic growth