Nowadays, more carriers and components are used in cellular networks to satisfy the requirement of high-speeddata service. The increase of carriers and components may result in serious problem of passive inter-modula...
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Nowadays, more carriers and components are used in cellular networks to satisfy the requirement of high-speeddata service. The increase of carriers and components may result in serious problem of passive inter-modulation （PIM）. This paper investigates the superposition effect of 3rd-order and 5th-order PIM under multicarrier scenarios with the channelized scheme （CS） and the multiplexed scheme （MS）. We use the concept of ＇effective hit＇ and the cumulative inter-modulation factors （CIFs） to evaluate the cumulative PIM product strength on each individual carrier within the receive signal band. Furthermore, with the simulator based on Monte-Carlo method, the group inter-modulation factor （GIF） is calculated to measure the average superposition effect for multiple carriers compared with the benchmark case. The simulation results show that, compared with the CS, the strength of PIM product with the MS does not increases so greatly with the growth of the total number of the carriers. The results are useful for the component designers and the cellular network planners.
In an isolated power converter, the inter-winding capacitances of the power transformer are critical parasitic capacitances for the generating of common mode (CM) noise. To suppress the CM noise in isolated power conv...
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ISBN:
(纸本)9781479957774
In an isolated power converter, the inter-winding capacitances of the power transformer are critical parasitic capacitances for the generating of common mode (CM) noise. To suppress the CM noise in isolated power converters, shielding-cancellation (SC) technique is proposed in this paper. The SC technique is realized by introducing noise cancellation on the basis of shielding, and it is easy to be implemented, suitable for various isolated power converters and independent of the transformer inter-winding capacitance. To verify the effectiveness of the SC technique on suppressing the CM noise, a flyback converter prototype is built, and the CM noise of the converter is measured and compared using three different transformers. It is revealed that the CM noise of the converter, which utilizes the transformer with SC technique, is lower than that using the transformer without shielding or with traditional shielding layers.
Content-based image retrieval often uses the integration of various features. The characteristic dimensions are up to hundreds of dimensions. The capabilities for image representation storage management far exceed tha...
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Content-based image retrieval often uses the integration of various features. The characteristic dimensions are up to hundreds of dimensions. The capabilities for image representation storage management far exceed that of the database. retrieval and matching of large-scale image are the urgent problems which need to be solved. To solve the construction of image indexing of large-scale image retrieval, this paper introduces a parallel level K-means clustering method. Firstly, image clustering based on the level K-means reduces the size of matching data in retrieval;secondly, considering the inherent defects in the cluster, we put forward optimization program and calculate clusterrapidly with parallel computing algorithms. The experimental results show that this method can quickly build a massive image index for fast image retrieval.
A high power internally matched GaN-HEMT amplifier at Ku-Band was successfully developed. In order to achieve high output power over the targeted bandwidth, a new balancing network is added to the gate side matching c...
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A high power internally matched GaN-HEMT amplifier at Ku-Band was successfully developed. In order to achieve high output power over the targeted bandwidth, a new balancing network is added to the gate side matching circuit. At 24 V drain supply voltage, the HPA delivers 80W of CW rF power with a PAE exceeding 22% over the 13.75-14.5 GHz frequency range. To the best of authors' knowledge, this output power is state-of-the-art for CW operation in this frequency band.
This paper presents a procedure of designing an offset Gregorian dual-reflector antenna with a non-circular aperture of the main reflector using FEKO. A 1.2m Ku band offset dual-reflector antenna is set as an example ...
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This paper presents a procedure of designing an offset Gregorian dual-reflector antenna with a non-circular aperture of the main reflector using FEKO. A 1.2m Ku band offset dual-reflector antenna is set as an example to compare the results from two solvers in FEKO with the measurement data. There are good agreements on the radiation patterns simulated in FEKO with those by measurement.
In this paper, we present an effective method to reconstruct a dense 3d model of an object or a scene by combining high resolution color anddepth images. Conventionally, multiple views of color images can be used for...
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In this paper, we present an effective method to reconstruct a dense 3d model of an object or a scene by combining high resolution color anddepth images. Conventionally, multiple views of color images can be used forreconstructing a 3d model of the captured scene. Although the conventional method can give the accuracy of the textured-regions of an object, it lacks density and leaves many holes in the texture-less regions. However, a depth camera is capable to capture 3ddistance information even in homogenous regions. Still, it gives low resolution and is unable to provide an accurate result of a detailed object. We thus propose a combined method of utilizing both high resolution color anddepth images to obtain a high-quality, accurate anddense 3d model. Compared to the conventional methods, our proposed method produces a much denser and more all-over 3dresults.
We propose a new edge preserve anddepth image recovery method in rGB-d camera systems that gives a sharp and accurate object shape from a noisy boundary depth map. The edges of an input depth image are detected and t...
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We propose a new edge preserve anddepth image recovery method in rGB-d camera systems that gives a sharp and accurate object shape from a noisy boundary depth map. The edges of an input depth image are detected and the noisy pixels around them are removed from the depth image. An anisotropic diffusion edge tensor of an input rGB image is computed. Missing depth pixels are then recovered using the total generalized variation optimization with guidance of the rGB-image edge tensor. Thus, accurate object depth boundary can be obtained and well aligned with the object edges in rGB images. The missing or invaliddepth pixels in the large hole areas and the thin object can also be recovered. Experimental results show the improvement in edge preserve anddepth image recovery with the expense on computation complexity when compared with previous works.
In order to overcome "semantic gap" between bottom features and high-level semantic in the image retrieval, this paper introduces the echo state network to strengthen the mapping between the high-level visio...
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In order to overcome "semantic gap" between bottom features and high-level semantic in the image retrieval, this paper introduces the echo state network to strengthen the mapping between the high-level vision content and the bottom visual feature anddesigns a feedback category screening strategy. We extract the feature of the queried image and get the characteristic vector of the image;through introducing the echo state network for image and constructing sample testing model for each kind of image data, we can calculate the category probability of the queried image, so as to achieve similarity discrimination of the queried image and library image. After users make feedbacks to the retrieval results and systems use related feedback algorithm to amend image feature, we retrieve and screen the category of the returned image. Experiments show that ourretrieval architecture can achieve very goodretrieval results.
This paper presents an estimation scheme of cell capacitor voltage for the Modular Multilevel Converter (MMC) to reduce the sampling data and its associated communication time coming from enormous number of cells in H...
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This paper presents an estimation scheme of cell capacitor voltage for the Modular Multilevel Converter (MMC) to reduce the sampling data and its associated communication time coming from enormous number of cells in HVdC application. For the control of cell capacitor voltage of each cell, it is necessary to know the state of the voltage and it is generally measured by voltage sensors. And, to sample the voltage of each cell at every sampling instant, the associated measurement and communication hardware and signal processing time would be prohibitive as the number of cells in each arm of MMC for HVdC application is above several hundreds. This paper presents an estimation of the cell capacitor voltages using submodule grouping and adaptive observer for estimating cell capacitance in order to reduce real time voltage measurement burdens. The simulation and experimental results verify that the proposed method can guarantees the stable operation of MMC with reduced number of the cell voltage sampling.
Theophylline (THO) molecular imprinted composite membranes(MIM) were successfully fabricated by thermal initiated free radical polymerization on the surface of α-Al2O3 ceramic microporous hollow fiber substrate membr...
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Theophylline (THO) molecular imprinted composite membranes(MIM) were successfully fabricated by thermal initiated free radical polymerization on the surface of α-Al2O3 ceramic microporous hollow fiber substrate membranes. Molecular imprinted polymerization layer was synthesized by taking theophylline as the template molecule, methacrylic acid(MAA) as the functional monomer, ethylene glycol dimethacrylate(EdMA) as the cross-linker, and 2,2'-azobisisobutyronitrile(AIBN) as the free radical initiator. After polymerization and the elution of imprinted molecule, the rmax(the maximum pore size) upon membrane surface decreased from 2.55 μm to 1.91 μm. The imprinted layer upon the ceramic membranes was investigated by scanning electron microscopy(SEM), atomic force microscope(AFM) and fourier transform infrared spectroscopy(FTIr). SEM micrographs showed a 1 μm thickness composite membrane and AFM showeddifferent surface roughness. Moreover, the selectivity separation factor of theophylline(THO) to theobromine(TB) was determined as 2.63 in a mixed feed solution, thus suggesting that the imprinting process allowed for preferential permeance and affinity selectivity to THO.
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