This paper presented a new shared cache technique-the grouping cache, which could solve many invalid queries in the broadcast probe and the control bottleneck of the centralized web cache by dividing all cooperative c...This paper presented a new shared cache technique-the grouping cache, which could solve many invalid queries in the broadcast probe and the control bottleneck of the centralized web cache by dividing all cooperative caches into several groups according to their positions in the network topology. The technique has the following characteristics: The overhead of multi-cache query can be reduced efficiently by the cache grouping scheme; the compact summary of the cache directory can rapidly determine if a request exists in a cache within the group; the distribution algorithm based on the web-access logs can effectively balance the load among all the groups. The simulation test demonstrated that the grouping cache was more effective than any other existing shared cache techniques.展开更多
This paper is concerned with the sensor nodes’ hardware design of the wireless sensor network.We focus on the electromagnetic compatibility design of the printed circuit board.In this paper,we will give a schematic d...This paper is concerned with the sensor nodes’ hardware design of the wireless sensor network.We focus on the electromagnetic compatibility design of the printed circuit board.In this paper,we will give a schematic diagram first,and then,according to the layout,wiring rules and the knowledge of electromagnetic compatibility, we will present the design of the printed circuit board which has a good characteristic of electromagnetic compatibility.展开更多
Considering that the noises resulting from low modulation frequency are serious and cannot be totally eliminated by the classic filters,a novel infrared(IR) gas concentration detection system based on the least square...Considering that the noises resulting from low modulation frequency are serious and cannot be totally eliminated by the classic filters,a novel infrared(IR) gas concentration detection system based on the least square fast transverse filtering(LS-FTF) self-adaptive modern filter structure is proposed.The principle,procedure and simulation on the LS-FTF algorithm are described.The system schematic diagram and key techniques are discussed.The procedures for the ARM7 processor,including LS-FTF and main program,are demonstrated.Comparisons between the experimental results of the detection system using the LS-FTF algorithm and those of the system without using this algorithm are performed.By using the LS-FTF algorithm,the maximum detection error is decreased from 14.3 to 5.4,and also the detection stability increases as the variation range of the relative error becomes much smaller.The proposed LS-FTF self-adaptive denoising method can be of practical value for mid-IR gas detection,especially for weak signal detection.展开更多
The antireflection properties of triangular shaped gratings are studied by a combination of the effective medium theory and the anisotropic thin-film theory. The triangular shaped structures are analyzed as a function...The antireflection properties of triangular shaped gratings are studied by a combination of the effective medium theory and the anisotropic thin-film theory. The triangular shaped structures are analyzed as a function of grating period, filling factor, and groove depth, and the antireflective characteristics are also studied when visible-infrared light is incident upon them. Numerical examples are given for gratings on glass substrate with refractive index of 1.5. The results show that this kind of grating is capable of reducing reflections, and could achieve very low reflectivity over a wide field of view and a wide waveband by choosing appropriate parameters.展开更多
文摘This paper presented a new shared cache technique-the grouping cache, which could solve many invalid queries in the broadcast probe and the control bottleneck of the centralized web cache by dividing all cooperative caches into several groups according to their positions in the network topology. The technique has the following characteristics: The overhead of multi-cache query can be reduced efficiently by the cache grouping scheme; the compact summary of the cache directory can rapidly determine if a request exists in a cache within the group; the distribution algorithm based on the web-access logs can effectively balance the load among all the groups. The simulation test demonstrated that the grouping cache was more effective than any other existing shared cache techniques.
基金supported by the National Nature Science Foundation of China(60804034)Nature Science Foundation of Shandong Province(Y2007G34)the second author is also supported by the "Taishan Scholarship" Construction Engineering
文摘This paper is concerned with the sensor nodes’ hardware design of the wireless sensor network.We focus on the electromagnetic compatibility design of the printed circuit board.In this paper,we will give a schematic diagram first,and then,according to the layout,wiring rules and the knowledge of electromagnetic compatibility, we will present the design of the printed circuit board which has a good characteristic of electromagnetic compatibility.
基金supported by the National "863" Project of China (Nos. 2007AA06Z112,2007AA03Z446 and 2009AA03Z442)the National Natural Science Foundation of China (No.61077074)the Science and Technology Department of Jilin Province of China (Nos. 20070709 and 20090422)
文摘Considering that the noises resulting from low modulation frequency are serious and cannot be totally eliminated by the classic filters,a novel infrared(IR) gas concentration detection system based on the least square fast transverse filtering(LS-FTF) self-adaptive modern filter structure is proposed.The principle,procedure and simulation on the LS-FTF algorithm are described.The system schematic diagram and key techniques are discussed.The procedures for the ARM7 processor,including LS-FTF and main program,are demonstrated.Comparisons between the experimental results of the detection system using the LS-FTF algorithm and those of the system without using this algorithm are performed.By using the LS-FTF algorithm,the maximum detection error is decreased from 14.3 to 5.4,and also the detection stability increases as the variation range of the relative error becomes much smaller.The proposed LS-FTF self-adaptive denoising method can be of practical value for mid-IR gas detection,especially for weak signal detection.
文摘The antireflection properties of triangular shaped gratings are studied by a combination of the effective medium theory and the anisotropic thin-film theory. The triangular shaped structures are analyzed as a function of grating period, filling factor, and groove depth, and the antireflective characteristics are also studied when visible-infrared light is incident upon them. Numerical examples are given for gratings on glass substrate with refractive index of 1.5. The results show that this kind of grating is capable of reducing reflections, and could achieve very low reflectivity over a wide field of view and a wide waveband by choosing appropriate parameters.
