Essays on knowledge sourcing and technological capability:A knowledge structure perspective

In today’s increasingly competitive and rapidly changing markets that depend heavily on innovation, firms are increasingly opt to use external knowledge sourcing strategies to complement their internal efforts in developing technological capabilities. While external knowledge sourcing strategy can bring substantial opportunities for new knowledge generation, it imposes huge challenges to the firms for successful integration of external knowledge, making appropriate execution of external knowledge sourcing strategies crucial. However, the literature and empirical evidence has not yet been able to offer a conclusive indication of what drives the performance variations of different firms in developing technological capabilities from sourcing knowledge externally. To address this under-explored question, this dissertation presents three empirical studies that examine the antecedents of the performance variations in developing technological capabilities through sourcing knowledge externally. By looking at firms’ external knowledge sourcing strategies in the three modes of governance with different levels of hierarchy (i.e. licensing, alliances, and acquisitions), the findings of this dissertation aim to improve our understanding of how external knowledge sourcing strategies can be better managed to develop technological capabilities

Research and Application of 3D Simulation Technology for Water Resources Digital Twin Platform

The physical simulation software and digital twin technology play a very important role in building a digital twin platform for water resources, which provides the necessary support to realize digital mapping and intelligent simulation of water resources production and operation. In order to promote the coordinated and efficient operation of different types of water modeling and the intelligence of watershed and water project governance processes, this project will carry out the research and application of process architecture and core technologies for water 3D simulation. The results of this project will provide the theoretical basis and technical support for the development of digital twin technology in the field of water resources in China and contribute to the development of water resources in China

Numerical simulation of the optimal two-mode attacks for two-way continuous-variable quantum cryptography in reverse reconciliation

We analyze the security of the two-way continuous-variable quantum key distribution protocol in reverse reconciliation against general two-mode attacks, which represent all accessible attacks at fixed channel parameters. Rather than against one specific attack model, the expression of secret key rates of the two-way protocol are derived against all accessible attack models. It is found that there is an optimal two-mode attack to minimize the performance of the protocol in terms of both secret key rates and maximal transmission distances. We identify the optimal two-mode attack, give the specific attack model of the optimal two-mode attack and show the performance of the two-way protocol against the optimal two-mode attack. Even under the optimal two-mode attack, the performances of two-way protocol are still better than the corresponding one-way protocol, which shows the advantage of making a double use of the quantum channel and the potential of long-distance secure communication using two-way protocol.Comment: 14 pages, 8 figure

Improvement of two-way continuous-variable quantum key distribution with virtual photon subtraction

We propose a method to improve the performance of two-way continuous-variable quantum key distribution protocol by virtual photon subtraction. The Virtual photon subtraction implemented via non-Gaussian post-selection not only enhances the entanglement of two-mode squeezed vacuum state but also has advantages in simplifying physical operation and promoting efficiency. In two-way protocol, virtual photon subtraction could be applied on two sources independently. Numerical simulations show that the optimal performance of renovated two-way protocol is obtained with photon subtraction only used by Alice. The transmission distance and tolerable excess noise are improved by using the virtual photon subtraction with appropriate parameters. Moreover, the tolerable excess noise maintains a high value with the increase of distance so that the robustness of two-way continuous-variable quantum key distribution system is significantly improved, especially at long transmission distance.Comment: 15 pages, 6 figure