指定验证者与可撤销重加密的可搜索加密方案

隐藏向量加密(hidden vector encryption, HVE)作为一种谓词加密策略,不仅可以对解密密钥进行细粒度的控制,同时也支持对关键词的合取和子集等范围搜索,因此可以被应用在诸如电子健康记录等系统中,以保护用户敏感数据并提供密文检索功能.然而,目前已有的隐藏向量加密策略均未考虑离线关键词测试攻击和可撤销的代理访问控制.针对这一问题,提出了一种支持指定验证者和基于时间的可撤销代理重加密的高效的隐藏向量加密方案.代理人可以在数据拥有者指定的时间区间内访问密文数据,而当超过预定的时间后,代理权限将被自动撤销.由于只有指定的验证者可以执行验证操作,使得方案可以有效地抵御离线关键词测试攻击.提出的可搜索加密方案不仅在标准模型下面对选择关键词、选择时间攻击是可证明安全的,同时,搜索令牌的尺寸、重加密算法的时间复杂度以及验证操作的双线性对运算次数均限定在O(1)常数界限内.因此,方案具有较好的安全性和实用效率.     

Simulation and evaluation of pilot-scale pulsed electric field (PEF) processing

Pulsed electric field (PEF) processing is a novel mild treatment for pumpable foods preservation at low or moderate temperatures. The electric field strength and the temperature distribution in the treatment chamber have been identified as the key processing parameters affecting the treatment efficacy and possibly the sensorial and nutritional quality of the food. A full 3D computational fluid dynamics (CFD) model of a pilot-scale PEF system with co-linear configuration of the electrodes was developed. The model couples the fluid dynamics and the electrical field and can be used to predict the liquid’s flow pattern, electric field distribution, temperature increase, and residence time in the treatment chamber. A total of 48 process conditions with different settings of applied voltage V, pulse length τ, pulse repetition rate (frequency) f and flow rate in combination with four different inlet temperatures were simulated for a model liquid food (NaCl solutions with two different electrical conductivities) and whole milk. The simulated PEF energy dissipated into the liquids was between 4 and 66 kJ/kg and process temperatures ranged from approximately 25 to 80 °C. The predicted temperature data agree well (R² > 0.99) with experimental measurements in five locations of the treatment chamber using fibre optic probes.     

论高职高专学报的发展思路

本主要通过对高职高专学报现状的分析．提出突出专业优势，办好特色栏目；改变封闭状态，扩大社会影响；提高编辑水平，注重服务质量；更新管理观念，促进学报进步的发展思路。     

从汉字书写看高职语文教学中的素质教育

本文从素质教育的角度出发,分析了高职语文教学中学生书写能力的现状,分析了影响学生书写能力提高的原因。从高职教育的特点出发,指出了高职学生加强文化素质培养,提高汉字书写能力的重要性。提出了高职语文书写教学的具体教学目标和实施方法。