排序方式: 共有27条查询结果,搜索用时 15 毫秒
1.
This paper deals with the problem of fast recognition of harmonic distortions by means of a wavelet transform. A method of fast detection of a frequency band affected by the high-frequency content and time of its occurrence is described. It is based on the auxiliary waveform distortion band factors (DBFs) calculated on the basis of wavelet coefficients. The merits of the presented method, as well as its limitations, are described on the basis of real voltages registered in ships' electrical power systems. This method is a part of the method based on the complementary application of Fourier and wavelet transforms, which was described in the previous papers of the author. However, this paper describes new research results and an expanded analysis exclusively focused on the aforementioned DBFs. 相似文献
2.
3.
E. Mingozzi G. Stea M.A. Callejo-Rodríguez J. Enríquez-Gabeiras G. García-de-Blas F.J. Ramón-Salquero W. Burakowski A. Beben J. Sliwinski H. Tarasiuk O. Dugeon M. Diaz L. Baresse E. Monteiro 《Computer Communications》2009,32(12):1355-1370
The EuQoS (End-to-End QoS over Heterogeneous Networks) IST Integrated European Project aimed to define a Next Generation Network architecture that builds, uses and manages end-to-end QoS across different administrative domains and heterogeneous networks (UMTS, xDSL, Ethernet, WiFi, Satellite and IP/MPLS). The EuQoS architecture preserves the openness and the decentralized decision model of the actual Internet, runs on off-the-shelf hardware and network equipment, and allows end users to request various services without changing the Application Signaling protocol, while meeting regulators’ and users’ Net Neutrality requirements. This paper presents the key elements of the EuQoS architecture and describes the main results obtained in field trials performed on a fully-functional EuQoS system prototype developed over a pan-European testbed. Furthermore, the paper discusses the main strengths of the system and the issues related to its actually deployment on a large scale, from both technical and market points of view. 相似文献
4.
5.
Cellular communication and the transfer of information from one cell to another is crucial for cell viability and homeostasis. During the last decade, tunneling nanotubes (TNTs) have attracted scientific attention, not only as a means of direct intercellular communication, but also as a possible system to transport biological cargo between distant cells. Peculiar TNT characteristics make them both able to increase cellular survival capacities, as well as a potential target of neurodegenerative disease progression. Despite TNT formation having been documented in a number of cell types, the exact mechanisms triggering their formation are still not completely known. In this review, we will summarize and highlight those studies focusing on TNT formation in the nervous system, as well as their role in neurodegenerative diseases. Moreover, we aim to stress some possible mechanisms and important proteins probably involved in TNT formation in the nervous system. 相似文献
6.
New polythioesters were obtained by interfacial polycondensation of 4,4′-dimercaptobiphenyl with selected aliphatic and isomeric phthaloyl dichlorides. To determine the optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of hydrogen chloride acceptor, type of catalyst, reaction temperature and rate of acid dichloride addition. A thorough examination was carried out only for the polycondensation of dithiol with isophthaloyl dichloride chosen as a model system. The structures of polythioesters were determined by elemental analysis, X-ray and infrared spectra. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process were determined from curves of differential and thermogravimetric analysis. Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters. 相似文献
7.
New polythioesters were synthesized by interfacial polycondensation of 4,4'-bis(mercaptomethyl)biphenyl with selected aliphatic and isomeric phthaloyl dichlorides. To determine optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of reagents, aqueous/organic phase ratio, type and concentration of hydrogen chloride acceptor, rate of acid chloride addition, reaction temperature and reaction time. A thorough examination was carried out only for the polycondensation of dithiol with adipoyl and isophthaloyl dichlorides chosen as a model system. The structures of polythioesters were confirmed by elemental analysis, X-ray analysis and infrared spectroscopy. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process from curves of differential and thermogravimetric analysis were determined. Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters. 相似文献
8.
The paper deals with measurement and control aspects of active power filtering in ship systems. The main focus of the paper is concentrated on improvement of harmonic current measurement algorithms based on ip–iq method with application of low-pass filter (LPF) module and, alternatively, on ip–iq method with application of mean value module. 相似文献
9.
Tomasz Tarasiuk 《Power Delivery, IEEE Transactions on》2007,22(1):4-17
This paper deals with a problem of fast and reliable waveform disturbances recognition. It means real-time detection and evaluation of different kinds of waveform distortions such as harmonics, interharmonics, as well as transients and notching. In this paper, the problems of sampling frequency, a resulting number of samples and a complementary application of Fourier transform and a wavelet transform have been described. The main focus of this paper has been placed on harmonics and harmonic subgroups analysis. However, there is an assumption that harmonics are to be measured concurrently with transient and notching by a single dedicated device. All analyses have been carried out for the real voltages waveforms registered in ship and land electric power systems 相似文献
10.