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Risk Management of Small & Medium-Sized Enterprises in Financial Crisis
Wang Wenzhao,Wu Wenbing,Wang Wencheng 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10
Small & medium-sized enterprises, which take up 99% of the total number of the enterprises in our nation, have been playing a very important role in keeping sustainable development of our national economy. Among them, the export-oriented processing trade enterprises are severely influenced by the financial crisis triggered from USA, which reveals that our small & medium-sized enterprises" weakness in risk analyzing, risk control and management. This article takes small & medium-sized enterprises in Pearl River Delta Region and Ningbo as examples to analyze the risk these enterprises face in financial crisis and to propose some related solutions.
Design and simulation analysis of innerouter compound meshing silent-chain plate
Wencheng Wang,Hui Liu,Guoqing Cai,Pengcheng Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9
This paper proposes a detailed parametric design method for a round-pin innerouter compound meshing silent-chain plate structure. A meshing design method for parameter harmonization among a silent chain, a sprocket hob, and an involute sprocket is proposed. To analyze the influence of extended arc parameters on the meshing process and impact, the extended arc parameter extension δ and height HY are considered as variables to formulate the motion-analysis model of the chain-drive system. The results reveal that the extended arc parameters δ and HY have a significant effect on the meshing process and the meshing impact. When δ and HY are optimal, the inner-outer compound meshing process of the chaindrive system can be smoothly realized; furthermore, the meshing impact force is minimal as it is reduced by more than 25 % compared to when only the outer meshing process occurs. Thus, the chain-plate structure is optimized.
Yang Bo,Qing Wang,Jinyu Wang,Yan Cai,Wencheng Yue,Shuxiao Wang,Wei Wang,Mingbin Yu 한국광학회 2023 Current Optics and Photonics Vol.7 No.2
We propose a highly directional waveguide grating antenna for an optical phased array, achieving high directionality of more than 97% by interleaving the trenches with different etching depths in the silicon nitride layer, and adopting a multilayered structure. Meanwhile, the multilayered structure reduces the perturbation strength, which enables a centimeter-scale radiation length. The beam-steeringrange is 13.2°, with a wavelength bandwidth of 100 nm. The 1-dB bandwidth of the grating is 305 nm. The multilayered grating structure has a large tolerance to the fabrication variation and is compatible with CMOS fabrication techniques.
Impact of feature proportion on matching performance of multi-biometric systems
Wencheng Yang,Song Wang,Guanglou Zheng,Craig Valli 한국통신학회 2019 ICT Express Vol.5 No.1
Biometrics as a tool for information security has been used in various applications. Feature-level fusion is widely used in the design of multi-biometric systems due to its advantages in increasing recognition accuracy and security. However, most existing multi-biometric systems that use feature-level fusion assign each biometric trait an equal proportion when combining features from multiple sources. For example, multi-biometric systems with two biometric traits commonly adopt a 50–50 feature proportion setting, which means that fused feature data contains half elements from each biometric modality. In this paper, we investigate the impact of feature proportion on the matching performance of multi-biometric systems. By using a fingerprint and face based multi-biometric system that applies feature-level fusion, we employ a random projection based transformation and a proportion weight factor. By adjusting this weight factor, we show that allocating unequal proportions to features from different biometric traits yields different matching performance. Our experimental results indicate that optimal performance, achieved with unequal feature proportions, could be better than the performance obtained with the commonly used 50–50 feature proportion. Therefore, the impact of feature proportion, which has been ignored by most existing work, should be taken into account and more study is required as to how to make feature proportion allocation benefit the performance of multi-biometric systems.
Combining a HMM with a Genetic Algorithm for the Fault Diagnosis of Photovoltaic Inverters
Zheng, Hong,Wang, Ruoyin,Xu, Wencheng,Wang, Yifan,Zhu, Wen The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
The traditional fault diagnosis method for photovoltaic (PV) inverters has a difficult time meeting the requirements of the current complex systems. Its main weakness lies in the study of nonlinear systems. In addition, its diagnosis time is long and its accuracy is low. To solve these problems, a hidden Markov model (HMM) is used that has unique advantages in terms of its training model and its recognition for diagnosing faults. However, the initial value of the HMM has a great influence on the model, and it is possible to achieve a local minimum in the training process. Therefore, a genetic algorithm is used to optimize the initial value and to achieve global optimization. In this paper, the HMM is combined with a genetic algorithm (GHMM) for PV inverter fault diagnosis. First Matlab is used to implement the genetic algorithm and to determine the optimal HMM initial value. Then a Baum-Welch algorithm is used for iterative training. Finally, a Viterbi algorithm is used for fault identification. Experimental results show that the correct PV inverter fault recognition rate by the HMM is about 10% higher than that of traditional methods. Using the GHMM, the correct recognition rate is further increased by approximately 13%, and the diagnosis time is greatly reduced. Therefore, the GHMM is faster and more accurate in diagnosing PV inverter faults.
Proposals for the Development Trend of Copycat Product in China
Chenchuang,Zhang Mingyu,Wang Wencheng 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10
Copycat products in China are currently mainly in the condition of imitating the products of international companies and innovating their new products in terms of design and function. During the conversion process of enhancing brand, further developing the innovation and applying for a patent, many problems existed such as copycat inertia, disordered competition, low-end value chain and co existence of both well-run and ill-run enterprises. Therefore, a series of ideas are proposed in this article for the further development of copycat industry.
Combining a HMM with a Genetic Algorithm for the Fault Diagnosis of Photovoltaic Inverters
Hong Zheng,Ruoyin Wang,Wencheng Xu,Yifan Wang,Wen Zhu 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
The traditional fault diagnosis method for photovoltaic (PV) inverters has a difficult time meeting the requirements of the current complex systems. Its main weakness lies in the study of nonlinear systems. In addition, its diagnosis time is long and its accuracy is low. To solve these problems, a hidden Markov model (HMM) is used that has unique advantages in terms of its training model and its recognition for diagnosing faults. However, the initial value of the HMM has a great influence on the model, and it is possible to achieve a local minimum in the training process. Therefore, a genetic algorithm is used to optimize the initial value and to achieve global optimization. In this paper, the HMM is combined with a genetic algorithm (GHMM) for PV inverter fault diagnosis. First Matlab is used to implement the genetic algorithm and to determine the optimal HMM initial value. Then a Baum-Welch algorithm is used for iterative training. Finally, a Viterbi algorithm is used for fault identification. Experimental results show that the correct PV inverter fault recognition rate by the HMM is about 10% higher than that of traditional methods. Using the GHMM, the correct recognition rate is further increased by approximately 13%, and the diagnosis time is greatly reduced. Therefore, the GHMM is faster and more accurate in diagnosing PV inverter faults.