基于小型FPGA的快速AES算法研究

AES算法在实时数据加密中的应用对其处理速度及在FPGA中实现的功耗和成本提出较高要求。针对上述情况,介绍一种基于小型FPGA的快速AES算法的改进方法,通过微处理器完成AES算法中的密钥扩展运算,同时采用共享技术实现加密和解密模块共享同一密钥。实验结果表明,该方法可有效提高处理速度,节省FPGA资源,降低芯片功耗。     

基于订单的服装企业生产排期算法

针对面向订单生产的服装上下游企业生产排期问题,提出以集中式供应链管理思想划分供应链角色的方法。分析订单驱动的工艺流程,面向核心企业建立加工商协调生产的排期模型。该问题的关键是合适的订单模型和加工商模型,通过考虑订单的重要性并设置条件筛选加工商,利用遗传算法实现更快求解。     

基于嵌入式Linux系统的电源管理软件

针对嵌入式系统的低功耗要求,提出高效的电源管理方案。在高级电源管理技术的基础上,增加启动加载程序对电源管理的支持,修改Linux内核代码以对S3C2440处理器和系统外设进行电源管理,建立用户空间电源管理守护进程。在YLP2440开发板上进行实验,实验结果表明,当系统处于空闲状态时,在2种典型的系统工作频率下,该电源管理软件系统可将系统功耗降低至未进行电源管理时的11.67%和12.96%。     

LTE-A系统中物理随机接入信道信号检测的仿真与实现

根据多普勒频移对物理随机接入信道（PRACH）信号检测产生的影响进行分析,划分出了中速、高速、超高速三种模式,并提出相应改进的信号检测算法。对中速模式,提出了基于频偏校正的前导检测算法;对高速模式,提出了多重滑窗峰值检测算法;对超高速模式,提出了基于整数倍子载波的频偏补偿前导检测算法。仿真结果表明,不同场景下PRACH信号通过加性高斯白噪声（AWGN）信道传输,接收端虚警率性能至少改善了3.8 dB;通过扩展典型城市信道模型（ETU）信道传输,虚警率性能至少提升了1 dB。与频域相关检测算法相比,所提算法提高了前导信号成功检测概率,减少了接入时延。     

基于深度置信网络Otsu混合模型的自动云检测算法

地球表面一半以上被云覆盖,卫星遥感图像中的云检测主要是人工检测识别或者半自动化方法,依赖人工干预,效率不高,难以满足实时或准实时应用的需要。为了提高卫星遥感数据的可用性,基于深度置信网络（DBN）和最大类间方差法,提出一种自动云检测算法——DOHM。该算法采用自适应阈值代替人工标定阈值,实现云检测的全自动化,将云检测的正确率提高到95%以上;DOHM算法选取了维度为9的特征向量作为检测网络的输入,输入特征向量的多样性,有利于网络更全面有效地捕捉到云的特点。     

臭氧——活性炭在净水厂设计中若干问题的探讨

臭氧—活性炭吸附工艺是目前常用的深度处理技术,臭氧预氧化和粉末活性炭投加措施也是应对微污染原水的有效处理措施。臭氧发生器作为深度处理技术的核心设备,如何合理经济选择氧源系统,科学确定臭氧发生器设备台数,明确设备的各种技术参数,使臭氧系统能够灵活适应各种运行工况和环境条件,是招标工作中需要密切关注的问题。臭氧—活性炭系统的防火防爆措施如何满足安全和消防部门的要求、活性炭吸附池池型对反冲洗效果的影响、系统管道及附件和臭氧接触池的防腐措施等关键因素在设计过程中容易被忽视。通过对近年来相关给水深度处理技术文献资料的归纳整理和综合分析,并结合近年来净水厂深度处理工程的设计体会和经验,提出了臭氧—活性炭技术在水厂设计应用中容易忽视的问题,并对适宜的解决方案进行了探讨。     

滤布滤池在污水深度处理工程中的试验研究

以某污水处理厂二沉池出水为原水,考察了滤布滤池用于城市污水深度处理的效果,并对其除污机理进行了分析。试验结果表明：滤布滤池工艺能有效去除污水中的SS ,出水可满足《城镇污水处理厂污染物排放标准》（GB 18918-2002）中一级A标准的要求,但对COD、氨氮及总氮等非SS形态污染物的去除效果不佳。机理分析表明,滤布滤池工艺的除污机理与传统的砂滤池类似,以“粘附作用”为主,但“筛滤作用”亦不容忽视。     

IMPOSSIBLE DIFFERENTIAL CRYPTANALYSIS OF MINI-AES

Impossible differential cryptanalysis is one of the cryptanalysis methods that are applicable to the new Advanced Encryption Standard (AES). In this paper, we present an introduction to the method by applying it on Mini-AES, the mini version of the AES published in Cryptologia recently.     

Use of ENVISAT/ASAR wide-swath data for timely rice fields mapping in the Mekong River Delta

Because of the importance of rice for the global food security and because of the role of inundated paddy fields in greenhouse gases emissions, monitoring the rice production world-wide has become a challenging issue for the coming years. Local rice mapping methods have been developed previously in many studies by using the temporal change of the backscatter from C-band synthetic aperture radar (SAR) co-polarized data. The studies indicated in particular the need of a high observation frequency. In the past, the operational use of these methods has been limited by the small coverage and the poor acquisition frequency of the available data (ERS-1/2, Radarsat-1). In this paper, the method is adapted for the first time to map rice at large scale, by using wide-swath images of the Advanced SAR (ASAR) instrument onboard ENVISAT. To increase the observation frequency, data from different satellite tracks are combined. The detection of rice fields is achieved by exploiting the high backscatter increase at the beginning of the growing cycle, which allows the production of rice maps early in the season (in the first 50 days). The method is tested in the Mekong delta in Vietnam. The mapping results are compared to existing rice maps in the An Giang province, with a good agreement (higher than 81%). The rice planted areas are retrieved from the maps and successfully validated with the official statistics available at each province (R² = 0.92). These results show that the method is useful for large scale early mapping of rice areas, using current and future C band wide-swath SAR data.     

Surface deformation from persistent scatterers SAR interferometry and fusion with leveling data: A case study over the Choushui River Alluvial Fan, Taiwan

The Choushui River Alluvial Fan (CRAF), one of the most important agricultural areas in Taiwan, suffers severe subsidence caused by groundwater withdrawal. We use 20 ENVISAT images from 2006 to 2008 to derive vertical deformation over CRAF by persistent scatterer interferometry (PSI), which effectively reduces errors affecting conventional DInSAR techniques. The pixel density over CRAF is 107.6 pixels/km², compared to 0.19 points/km² of the leveling benchmarks. PSI yields vertical displacements matching the leveling result to 0.6 cm/year (RMS), and provides a higher spatial resolution of subsidence than the latter. We also develop a data fusion method that considers the high-precision, low point-density leveling result as a smoothed correction to the PSI result. The combined field is more representative of overall deformation characteristics than the PSI-only or leveling-only field, and it is better suited for the assessment of the impact of subsidence over CRAF.