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151.
H. Maurer O. Univ.-Prof. Dr. phil. 《e & i Elektrotechnik und Informationstechnik》2003,120(11):411-413
In this article it is argued that in ten years’ time personal computers as we know them now won’t exist anymore — all their functions will by then be integrated in mobiles which will be our steady companions. As such, mobiles will change our lives to an enormous extent. Technology as well as consequences will be discussed in this paper. 相似文献
152.
C. Arunachalaperumal Dr. C. Arun S. Dhilipkumar G. Abija 《Journal of Communications Technology and Electronics》2014,59(11):1247-1252
In recent years, it has been realized that the Multiple Input Multiple Output (MIMO) communication system is inevitable in accelerating the evolution of high data rate applications. Also the latest research in Information and Communication Technology has told that considerable gains in capacity of wireless communication are feasible in MIMO systems. MIMO with Space Time Trellis Code (STTC) offers both diversity gain and coding gain. This paper discusses the evolutional variants of Space Time Trellis Code developed over a decade. The performance of New Trellis code for STTC, STTC for 4-PSK, Space Frequency Trellis code (SFTC), Space Time Bit Trellis Code, and Silver STTC have been studied and discussed. STTC with Trellis Coded Modulation creates a bandwidth efficient system with coding gain. 相似文献
153.
Influence of loading method and stocking density during transport on meat and dry-cured ham quality in pigs with different halothane genotypes 总被引:1,自引:0,他引:1
The effect of loading method and stocking density in transit on meat and dry-cured ham quality was investigated in pigs with different halothane genotypes. A total of 507 Italian heavy pigs, supplied by two farms, were loaded by ramp or lift and transported unmixed for 35–55 min to the abattoir at a stocking density of either <0.4 or >0.6m2 per 100 kg pigs. After overnight lairage in separate pens with free access to water, the pigs were slaughtered. Halothane genotype was assessed post mortem. Four hundred and thirty-nine pigs had a homozygous dominant (NN) genotype and 68 pigs were heterozygous (Nn). Carcass skin damage, meat quality traits and ham curing parameters were evaluated. Loading method and stocking density showed a negligible effect on meat and dry-cured ham quality while the predominant factor affecting these was the halothane genotype. Nn pigs produced meat with a faster rate of pH fall and lower water holding capacity as well as ham with higher weight losses in salting and greater incidence of defects in the dry-cured product. There were insignificant interactions between halothane genotype and loading method or stocking density. Overall, irrespective of pre-slaughter treatment, the Nn pigs were less suitable for the production of high quality products such as dry-cured ham. 相似文献
154.
Dr. techn. Dr. tekn. h.c. Prof. Emeritus J?rgen Bach Andersen M.Sc. Ph.D. Prof. Gert Fr?lund Pedersen 《e & i Elektrotechnik und Informationstechnik》2012,129(6):383-386
In future mobile communications many antennas will coexist on the device. This creates a number of problems related to bandwidth, efficiency, and correlation. Remedies are discussed in the paper, and attention is called to the promising area of adaptive matching, which also can solve problems related to the user. 相似文献
155.
156.
A. Molisch Prof. Dipl.-Ing. Dr. techn. 《e & i Elektrotechnik und Informationstechnik》2005,122(3):85-90
MIMO (multiple-input-multiple-output) systems propose enormous gains in the capacity of wireless systems without requiring more spectral resources. This paper first gives an overview of the use of MIMO for diversity and spatial multiplexing, and the use of channel state information in MIMO systems. It then explores the use of antenna selection as a means for the reduction of the hardware complexity. It is shown that the performance in a spatial-multiplexing application is almost as good as that of full-complexity systems as long as the number of RF chains is at least as large as the number of data streams. 相似文献
157.
A. Kugi Univ.-Prof. Dipl.-Ing. Dr. techn. T. Kiefer Dipl.-Ing. 《e & i Elektrotechnik und Informationstechnik》2005,122(9):300-307
This contribution is devoted to the nonlinear tracking control problem of the laboratory experiment helicopter 3DOF distributed by Quanser. The laboratory experiment belongs to the class of mechanical systems with three degrees-of-freedom and two control inputs. It is well known that the systematic design of nonlinear controllers for underactuated mechanical systems is a challenge compared to fully actuated systems. On certain simplifying assumptions, which very well apply to the operating range of practical interest, we can show that the mathematical model is configuration flat. Thereby, a mechanical system is said to be configuration flat if it is differential flat and the flat outputs solely depend on the generalized coordinates of the mechanical system. The controller design is based on a formulation of the mechanical system on a Riemannian manifold where the kinetic energy serves as a natural Riemannian metric. In a first step a nonlinear tracking controller including an integral part in the linear error system is designed by means of a quasi-static state feedback. In a second step the design of the tracking controller is based on the theory of exact linearization utilizing the so-called dynamic extension algorithm. The experimental results of both controllers are compared and discussed in detail. In particular, the quasi-static state feedback controller shows an excellent tracking behavior. The performance as being obtained by the nonlinear controlled cannot be achieved by conventional linear control strategies. 相似文献
158.
S. Fuchshumer Dipl.-Ing. K. Schlacher O. Univ.-Prof. Dipl.-Ing. Dr. techn. T. Rittenschober Mag. Dipl.-Ing. 《e & i Elektrotechnik und Informationstechnik》2005,122(9):319-324
This contribution is primarily concerned with the system analysis of the bicycle dynamics, revealing the differential flatness property as a main result. A physically relevant representative for the flat output is introduced, with its components given as the lateral and the longitudinal velocity of a distinguished point located on the longitudinal axis of the vehicle. This flatness property is shown for the front-, rear- and all-wheel driven vehicle, without referring to particular representatives of the functions modelling the lateral tire forces. Following the flatness based control theory, a novel approach to nonlinear vehicle dynamics control is discussed. 相似文献
159.
概述了采用一个激光源能够加工刚性和挠性板的一种新型激光技术,PCB制造商可能采用最小的投资和提高生产率而进入HDI市场。 相似文献
160.
Panagiotis I. Dallas Dr. Fotini-Niovi Pavlidou 《International Journal of Wireless Information Networks》1996,3(3):163-172
DS/CDMA noncoherentM-ary orthogonal signaling is presented in a hexagonal cell with three and six corner-based antennas. Multipath Rayleigh channel
with lognormal shadowing and perfect power control are assumed. The asynchronous case (uplink) is studied. Bit error rate
analysis is carried out to investigate the benefits of combining theM-ary orthogonal signaling and macrodiversity techniques either with uncorrelated or correlated base stations. Comparative
analysis between the one central antenna arrangement and the proposed one is presented. The results show that the combination
ofM-ary signaling with multiple corner-based antennas improves system performance especially in terms of accommodating more users
and supporting new services. The results also show that shadowing does not degrade system performance significantly. 相似文献