A Fault-Tolerant Control Strategy for Three-level Neutral-Point Clamped (NPC) Inverter

When the open-circuit fault occurs on neutral-point clamped (NPC) inverters, it can cause the distortion of output currents, excessively large fluctuation of output voltages, and unbalanced neutral-point potential. Currently, several existing fault diagnosis methods are able to identify the fault types, but they are unable to identify the switching devices where the open-circuit faults occur. Furthermore, even if the open-circuit faults can be identified, the implications caused by open-circuit faults need to be further addressed. This thesis is focused on diagnosing the open-circuit faults and mitigating the problems caused by these faults. An effective fault diagnosis method is proposed in his study to identify the switching devices where the open-circuit faults occur. The characteristics of different distorted currents are firstly analyzed. By normalizing the sampling currents, calculating the average currents and comparing them with thresholds, different faulty switching devices can all be identified. To address the issues caused by these faults, a fault-tolerant control strategy is proposed. By replacing the impossible space vectors caused by these faults with other vectors which can generate the same output voltages, the problems of distortion of output currents and excessively large fluctuation of output voltages can be solved. But the excessively large difference of neutral-point potential still exists. To address the above issue, a model predictive control strategy is proposed to solve the problem of excessively large difference of neutral-point potential. A cost function is built to track the reference vector and suppress the difference of neutral-point potential. The Lagrange function is used to solve the action times of different space vectors. Furthermore, it is shown that when the neutral-point potential is initially unbalanced, the developed strategy is still able to make the potential balanced and greatly reduce its fluctuation

N-[2-Chloro-6-(4-chloro-6-methoxy­pyrimidin-2-ylsulfan­yl)benz­yl]-3,4-dimethyl­aniline

In the title mol­ecule, C20H19Cl2N3OS, the dihedral angle between the two benzene rings is 79.3 (7)°. The 4-chloro-6-methoxy­pyrimidine group is rotationally disordered over two sites by approximately 180°, the ratio of the refined occupancies being 0.6772 (15):0.3228 (15). Both disorder components of disorder are involved in intra­molecular N—H⋯N hydrogen bonds

Model Checking Temporal Logic Formulas Using Sticker Automata

As an important complex problem, the temporal logic model checking problem is still far from being fully resolved under the circumstance of DNA computing, especially Computation Tree Logic (CTL), Interval Temporal Logic (ITL), and Projection Temporal Logic (PTL), because there is still a lack of approaches for DNA model checking. To address this challenge, a model checking method is proposed for checking the basic formulas in the above three temporal logic types with DNA molecules. First, one-type single-stranded DNA molecules are employed to encode the Finite State Automaton (FSA) model of the given basic formula so that a sticker automaton is obtained. On the other hand, other single-stranded DNA molecules are employed to encode the given system model so that the input strings of the sticker automaton are obtained. Next, a series of biochemical reactions are conducted between the above two types of single-stranded DNA molecules. It can then be decided whether the system satisfies the formula or not. As a result, we have developed a DNA-based approach for checking all the basic formulas of CTL, ITL, and PTL. The simulated results demonstrate the effectiveness of the new method

VALUE CREATION THROUGH INTER-ORGANIZATIONAL SYSTEMS (IOS): FROM GOVERNANCE PROCESS VIEW

In this study, we seek to reveal the mechanism of value creation between firms and their partners in B2B context. An integrated conceptual model is constructed grounded in the co-creation theory and the process view, which proposes the interaction between relational assets, IOS support and governance process, as well as their impacts on co-created value. It differs from previous studies by highlighting the mediating effect of governance on value creation. Using a sample of 181 collected from China, our analysis indicates the contribution of governance to co-created value, which is generated through IOS and relational assets. In fact, the IOS support and relational assets alone don’t hold the answer to value co-creation, but they affect the mediating process and enable governance to create value. Especially, the IOS could accommodate the use of relational assets and significantly affect governance process, which is found to be fundamental in value creation. While commodity-like resources have diminishing value in co-creation, governance process with causal ambiguity, social complexity and organizational interconnectedness, becomes the main source of co-created value. Overall, our research sheds light on the key drivers of value co-creation, and provides insights to their impacts on value creation