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新一代运载火箭整流罩全频域声振分析及隔声降噪研究 被引量:7
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作者 胡迪科 沈林 +1 位作者 柳征勇 李跃明 《上海航天》 2016年第B05期29-35,共7页
介绍了新一代运载火箭整流罩全频域声振分析及隔声降噪研究。阐述了全频域分析用于中频的有限元结合统计能量(FE-SEA)混合分析方法的基本原理。以新一代整流罩为研究对象,分别用有限元(FEM),FESEA,统计能量(SEA)法建立了低、中、高频段... 介绍了新一代运载火箭整流罩全频域声振分析及隔声降噪研究。阐述了全频域分析用于中频的有限元结合统计能量(FE-SEA)混合分析方法的基本原理。以新一代整流罩为研究对象,分别用有限元(FEM),FESEA,统计能量(SEA)法建立了低、中、高频段的整流罩模型,分析了整流罩内有效载荷的噪声环境和随机振动响应。比较了复合材料和金属材料整流罩的降噪效果,发现在中低频段复合材料整流罩的隔声效果优于铝合金,在中高频段铝合金整流罩的隔声效果更好。为进一步改善复合材料整流罩内噪声环境,通过在整流罩内贴吸声材料对整流罩进行隔声降噪,结果表明在整流罩内壁增加聚酰亚胺泡沫可明显降低高频段的噪声,提高整流罩的隔声降噪能力,内声场随吸声材料厚度增加而降低(厚度20,30,50mm分别可降低2.1,5.38,9.51dB)。 展开更多
关键词 整流罩 有效载荷 全频域 混合建模 有限元结合统计能量法 声振响应 隔声降噪 聚酰亚胺
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Improved Automotive CAN Protocol Based on Payload Reduction and Selective Bit Stuffing
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作者 B. Vinodh Kumar J. Ramesh 《Circuits and Systems》 2016年第10期3415-3429,共15页
In this research paper, the implementation strategies of automotive controller area network protocol are investigated and the short messaging scheme with selective bit stuffing method to improve the effective utilizat... In this research paper, the implementation strategies of automotive controller area network protocol are investigated and the short messaging scheme with selective bit stuffing method to improve the effective utilization of its bandwidth has been proposed. There would be a sharp decrease in the performance of traditional CAN protocol because of considerable increase in the number of ECUs (Electronic Control Units) and infotainment gadgets connected in the vehicle architecture. The demand for safety, emission, diagnostics and comfort norms has steeply increased the number of messages in the 250 Kbps CAN network as the computational power of ECUs has gone up. To overcome this problem, the short CAN method has been proposed and the work is benchmarked with SAEJ1939 Heavy commercial vehicle CAN standard. The Matlab Simulink based short CAN has been modeled and the performance of the proposed system has evaluated using virtual instrument cluster. Experimental results have shown that compared to the traditional CAN, the proposed method has reduced the worst case response time of CAN extended frame from 160 μ sec to 144 μ sec. Selective bit stuffing technique has reduced the impact of bit stuffing over the payload and improved the utilization factor for the CAN bus without affecting the CAN message ID properties. The proposed algorithm has been modeled and simulated using CAN Matlab model Simulink and it has been verified using virtual CAN tool and real time CAN bus hardware. 展开更多
关键词 CAN Selective Bit Stuffing payload reduction Worst Case Response Time
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网络安全告警降噪基线的智能生成方法
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作者 王星凯 吴复迪 +2 位作者 童明凯 薛见新 张润滋 《信息安全研究》 CSCD 2023年第10期986-992,共7页
网络安全运营往往通过预置的基线规则组等方法来过滤告警,在复杂的场景中难以深入适配企业的具体网络和业务环境.随着企业信息化业务的不断扩展,复杂的网络攻击通常隐藏在海量告警中,造成告警疲劳的现象,严重影响安全运营团队的运营效率... 网络安全运营往往通过预置的基线规则组等方法来过滤告警,在复杂的场景中难以深入适配企业的具体网络和业务环境.随着企业信息化业务的不断扩展,复杂的网络攻击通常隐藏在海量告警中,造成告警疲劳的现象,严重影响安全运营团队的运营效率.提出一种智能的算法用于生成可解释的网络安全告警降噪基线.面向告警载荷进行数据挖掘建立基线,帮助运营人员在不了解公司环境和业务的情况下对海量的告警进行过滤,提升安全运营的效率.最终,在某大型公司的实际生产环境验证发现生成的降噪基线可以有效地过滤告警. 展开更多
关键词 告警 载荷 可解释基线 告警降噪 安全运营
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