Security is a nonfunctional information system attribute that plays a crucial role in wide sensor network application domains. Security risk can be quantified as the combination of the probability that a sensor networ...Security is a nonfunctional information system attribute that plays a crucial role in wide sensor network application domains. Security risk can be quantified as the combination of the probability that a sensor network system may fail and the evaluation of the severity of the damage caused by the failure. In this paper, we devise a methodology of Rough Outlier Detection (ROD) for the detection of security-based risk factor, which originates from violations of attack requirements (namely, attack risks). The methodology elaborates dimension reduction method to analyze the attack risk probability from high dimensional and nonlinear data set, and combines it with rough redundancy reduction and the distance measurement of kernel function which is obtained using the ROD. In this way, it is possible to determine the risky scenarios, and the analysis feedback can be used to improve the sensor network system design. We illustrate the methodology in the DARPA case set study using step-by-step approach and then prove that the method is effective in lowering the rate of false alarm.展开更多
A new coarse tuning loop for a wide-band dual-loop frequency synthesizer is presented. The coarse tuning structure is composed of two digital modules, including a successive approximation register and a frequency comp...A new coarse tuning loop for a wide-band dual-loop frequency synthesizer is presented. The coarse tuning structure is composed of two digital modules, including a successive approximation register and a frequency comparator with a novel structure. The frequency comparator counts the prescaler cycles within a certain reference time and compares the number with preset data to estimate the VCO frequency. The frequency comparison error is analyzed in detail. Within a given coarse tuning time,our proposed structure shows a comparison error 20 times smaller than that of other reported structures. This structure also reuses the programmable divider as a part of the coarse tuning loop so that the circuit is greatly simplified.展开更多
To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for desig...To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for designing a new robotic helical milling hole system, which could further improve robotic hole-making ability in airplane digital assembly. After analysis on the characteristics of helical milling hole, advantages and limitations of two typical robotic helical milling hole systems were summarized. Then, vector model of helical milling hole movement was built on vector analysis method. Finally, surface roughness calculation formula was deduced according to the movement principle of helical milling hole, then the influence of main technological parameters on surface roughness was analyzed. Analysis shows that theoretical surface roughness of hole becomes poor with the increase of tool speed ratio and revolution radius. Meanwhile, the roughness decreases according to the increase of tool teeth number. The research contributes greatly to the construction of roughness prediction model in helical milling hole.展开更多
In this paper, gasification was utilized in order to produce syngas from crude glycerol and palm shell waste which are by-product of biodiesel production. Experiments were carried out in a fluidized bed quartz reactor...In this paper, gasification was utilized in order to produce syngas from crude glycerol and palm shell waste which are by-product of biodiesel production. Experiments were carried out in a fluidized bed quartz reactor using alumina ball with 1 mm diameter as fluidizing medium with equivalent ration of 0.05 with raw materials （mixed crude glycerol and palm shell wastes） at 10 g/min feed rate under 700℃ and 900℃. Glycerol and palm shell powder were fed separately to gasifier at different weight ratio varied from 100：0, 70：30, 50：50, 30：70, 0：100. Decomposition of crude glycerol resulted in much less char when compared with other biomass. From the results, it could be found that combustible gas productions increased with the increasing of crude glycerol fraction and temperature; syngas production was highest at 900℃with only glycerol in feed; gas production rate yields under optimum condition were 4.29% CO2, 8.70% CO, 10.48% H2, and 8.24% CH4 L/min; LHV and H2/CO at optimum condition were 4.87 MJ/m^3 and 1.20, respectively, which were sufficient for power utilization. Obtained H2/CO ratio also indicated that syngas from gasification of crude glycerol and palm shell waste should be suitable for further conversion to methanol and other chemical reagents, and thus closing the chemical recovery cycle of biodiesel production process to ensure the sustainahility status for the use of biodiesel as a prominent renewable energy source.展开更多
A liquid-solid fluidized bed separator, used for the separation of coarse slime, was developed. Test parti- cles sized in the range from 0.25 to 0.5, 0.5 to 1.0, and 0.25 to 1.0 mm were separated in the liquid-solid f...A liquid-solid fluidized bed separator, used for the separation of coarse slime, was developed. Test parti- cles sized in the range from 0.25 to 0.5, 0.5 to 1.0, and 0.25 to 1.0 mm were separated in the liquid-solid fluidized bed. Beds with column heights of 1200, 1500, and 1800 mm were tried. The clean coal and the railings were subsequently analyzed by float-sink testing. The results showed that the ash and yield of clean coal both decreased with increasing column height, for all three size fractions, and that the ash of the clean coal obtained from tests on the broader size fraction was less than that from the narrower sized fractions. The separation density decreased with increasing column height. The lowest E value was seen for a column height of 1500 ram, for which conditions the separation density was 1.45 g/cm3. The E value was 0.084 for the 0.25-0.5 mm fraction but the corresponding separation density was 1.48 g/cm3, and the E value 0.089, for the broader 0.25-1.0 mm fraction.展开更多
This paper presents a method for determining the percentage of coarse aggregate in concrete specimens by image processing. The test pieces were produced with the aim of obtaining images of their cross sections through...This paper presents a method for determining the percentage of coarse aggregate in concrete specimens by image processing. The test pieces were produced with the aim of obtaining images of their cross sections through a scanner table. In order to increase the contrast between mortar and coarse aggregate the sliced surfaces were treated with the phenolphthale in solution. The images obtained in the scanner were processed in a program developed with MATLAB （matrix laboratory）. The average coarse aggregate in each section and the mean of coarse aggregate per test body were calculated. With the results, it was revealed that the method returned satisfying results when compared to the original trace of the concrete.展开更多
基金the Jiangsu 973 Scientific Project，the National Natural Science Foundation of China，the Jiangsu Natural Science Foundation，the Aerospace Innovation Fund，the Lianyungang Science & Technology Project
文摘Security is a nonfunctional information system attribute that plays a crucial role in wide sensor network application domains. Security risk can be quantified as the combination of the probability that a sensor network system may fail and the evaluation of the severity of the damage caused by the failure. In this paper, we devise a methodology of Rough Outlier Detection (ROD) for the detection of security-based risk factor, which originates from violations of attack requirements (namely, attack risks). The methodology elaborates dimension reduction method to analyze the attack risk probability from high dimensional and nonlinear data set, and combines it with rough redundancy reduction and the distance measurement of kernel function which is obtained using the ROD. In this way, it is possible to determine the risky scenarios, and the analysis feedback can be used to improve the sensor network system design. We illustrate the methodology in the DARPA case set study using step-by-step approach and then prove that the method is effective in lowering the rate of false alarm.
文摘A new coarse tuning loop for a wide-band dual-loop frequency synthesizer is presented. The coarse tuning structure is composed of two digital modules, including a successive approximation register and a frequency comparator with a novel structure. The frequency comparator counts the prescaler cycles within a certain reference time and compares the number with preset data to estimate the VCO frequency. The frequency comparison error is analyzed in detail. Within a given coarse tuning time,our proposed structure shows a comparison error 20 times smaller than that of other reported structures. This structure also reuses the programmable divider as a part of the coarse tuning loop so that the circuit is greatly simplified.
基金Foundation item： Projects（50975141, 51005118） supported by the National Natural Science Foundation of China Projects（20091652018, 2010352005） supported by Aviation Science Fund of China Project（YKJ11-001） supported by Key Program of Nanjing College of Information Technology Institute, China
文摘To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for designing a new robotic helical milling hole system, which could further improve robotic hole-making ability in airplane digital assembly. After analysis on the characteristics of helical milling hole, advantages and limitations of two typical robotic helical milling hole systems were summarized. Then, vector model of helical milling hole movement was built on vector analysis method. Finally, surface roughness calculation formula was deduced according to the movement principle of helical milling hole, then the influence of main technological parameters on surface roughness was analyzed. Analysis shows that theoretical surface roughness of hole becomes poor with the increase of tool speed ratio and revolution radius. Meanwhile, the roughness decreases according to the increase of tool teeth number. The research contributes greatly to the construction of roughness prediction model in helical milling hole.
文摘In this paper, gasification was utilized in order to produce syngas from crude glycerol and palm shell waste which are by-product of biodiesel production. Experiments were carried out in a fluidized bed quartz reactor using alumina ball with 1 mm diameter as fluidizing medium with equivalent ration of 0.05 with raw materials （mixed crude glycerol and palm shell wastes） at 10 g/min feed rate under 700℃ and 900℃. Glycerol and palm shell powder were fed separately to gasifier at different weight ratio varied from 100：0, 70：30, 50：50, 30：70, 0：100. Decomposition of crude glycerol resulted in much less char when compared with other biomass. From the results, it could be found that combustible gas productions increased with the increasing of crude glycerol fraction and temperature; syngas production was highest at 900℃with only glycerol in feed; gas production rate yields under optimum condition were 4.29% CO2, 8.70% CO, 10.48% H2, and 8.24% CH4 L/min; LHV and H2/CO at optimum condition were 4.87 MJ/m^3 and 1.20, respectively, which were sufficient for power utilization. Obtained H2/CO ratio also indicated that syngas from gasification of crude glycerol and palm shell waste should be suitable for further conversion to methanol and other chemical reagents, and thus closing the chemical recovery cycle of biodiesel production process to ensure the sustainahility status for the use of biodiesel as a prominent renewable energy source.
基金supports for this work provided by the National Natural Science Foundation of China (No. 50974120)the Fundamental Research Funds for the Central Universities (No.2010QNB08)
文摘A liquid-solid fluidized bed separator, used for the separation of coarse slime, was developed. Test parti- cles sized in the range from 0.25 to 0.5, 0.5 to 1.0, and 0.25 to 1.0 mm were separated in the liquid-solid fluidized bed. Beds with column heights of 1200, 1500, and 1800 mm were tried. The clean coal and the railings were subsequently analyzed by float-sink testing. The results showed that the ash and yield of clean coal both decreased with increasing column height, for all three size fractions, and that the ash of the clean coal obtained from tests on the broader size fraction was less than that from the narrower sized fractions. The separation density decreased with increasing column height. The lowest E value was seen for a column height of 1500 ram, for which conditions the separation density was 1.45 g/cm3. The E value was 0.084 for the 0.25-0.5 mm fraction but the corresponding separation density was 1.48 g/cm3, and the E value 0.089, for the broader 0.25-1.0 mm fraction.
文摘This paper presents a method for determining the percentage of coarse aggregate in concrete specimens by image processing. The test pieces were produced with the aim of obtaining images of their cross sections through a scanner table. In order to increase the contrast between mortar and coarse aggregate the sliced surfaces were treated with the phenolphthale in solution. The images obtained in the scanner were processed in a program developed with MATLAB （matrix laboratory）. The average coarse aggregate in each section and the mean of coarse aggregate per test body were calculated. With the results, it was revealed that the method returned satisfying results when compared to the original trace of the concrete.
