解读教育技术的职业道德规范

教育技术2004新定义明确指出,教育技术是教育过程中符合一定伦理规范的促进学习的行为实践,并提出了25条具体的教育技术道德规范,认为所有参与教育技术的人员和组织都必须遵守这些道德规范才能使组织和个人保持较高的行业水准和取得较好的绩效。重视和引入教育技术规范,必将对推进我国教育领域乃至全社会各行各业职业道德建设起到积极的促进作用。     

钢球侵彻不同靶标的相似性分析

为研究相同弹丸侵彻不同靶标所造成损伤之间的相似性,以钢球侵彻明胶造成的瞬时空腔的最大直径为研究对象,基于相似理论推导出瞬时空腔最大直径的相似准则方程,利用钢球侵彻明胶的实验数据求解出准则方程的系数和指数,最后通过钢球侵彻猪后腿实验验证了所得到的准则方程可用于不同靶标之间的相似性分析,并具有准确性和合理性。     

模糊决策融合的红外弱小目标序列检测

针对红外序列图像中运动弱小点目标的检测问题,重点研究序列关联检测算法.在多帧关联检测的基础上,引入决策融合概念,建立了基于模糊决策融合的序列关联检测方法.基于贝叶斯最小风险准则建立分布式决策模糊融合方法,有效融合单帧检测的结果,提高序列检测算法的性能.实测数据的实验结果验证了基于贝叶斯最小风险准则的分布式决策模糊融合方法的可行性和有效性.     

基于贝叶斯网络分类器的雷达辐射源识别方法

雷达辐射源识别是电子对抗中的重要组成部分.贝叶斯网络分类器建立在坚实的理论基础之上,具有较为优秀的分类性能,而且能够有效地处理不确定性问题,重点研究了如何利用贝叶斯网络分类器进行雷达辐射源识别,并通过仿真实验对朴素贝叶斯分类器及其扩展方法进行了分析比较.实验结果表明,与基于概率近似准则的方法相比,基于分类准确率提高准则的扩展树生成方法具有更为优秀的分类性能.     

效力准则的电子战干扰效果度量的研究

探讨了舰载电子战系统干扰效果的度量准则,分析了压制干扰对反舰导弹的单发命中概率的影响,从研究系统射击效力指标的角度出发,提出一种新的评定舰载电子战干扰效果的准则——效力准则。并通过算例得出典型情况下系统施放压制性干扰时机与反舰导弹单发命中概率之间的关系。     

A novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise,minimum mean square variance criterion and least mean square adaptive filter

Underwater acoustic signal processing is one of the research hotspots in underwater acoustics. Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing. Owing to the complexity of marine environment and the particularity of underwater acoustic channel, noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing. In order to solve the dilemma, we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), minimum mean square variance criterion (MMSVC) and least mean square adaptive filter (LMSAF). This noise reduction technique, named CEEMDAN-MMSVC-LMSAF, has three main advantages: (i) as an improved algorithm of empirical mode decomposition (EMD) and ensemble EMD (EEMD), CEEMDAN can better suppress mode mixing, and can avoid selecting the number of decomposition in variational mode decomposition (VMD); (ii) MMSVC can identify noisy intrinsic mode function (IMF), and can avoid selecting thresholds of different permutation entropies; (iii) for noise reduction of noisy IMFs, LMSAF overcomes the selection of decomposition number and basis function for wavelet noise reduction. Firstly, CEEMDAN decomposes the original signal into IMFs, which can be divided into noisy IMFs and real IMFs. Then, MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs. Finally, both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained. Compared with other noise reduction techniques, the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals, which has the better noise reduction effect and has practical application value. CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection, feature extraction, classification and recognition of underwater acoustic signals.     

软件测试中的路径划分技术

路径覆盖测试准则要优于其它已知的覆盖准则,但由于对一般的软件,路径数目太大,以至实际难以实现。路径划分是路径覆盖技术的一个折中方法。给定的程序Ｐ和给定模块的最大路径数目ｋ,按就近原则,现给出了一种划分Ｐ的算法,使得每个划分后的模块所包含的路径数目都少于等于ｋ。同时也给出了最佳划分的度量标准和最佳划分方法。     

舰载反潜直升机吊放声纳区域反潜策略建模

为提高舰载反潜直升机吊放声纳区域反潜搜索作战效能,对舰载反潜直升机吊放声纳区域反潜搜索策略问题进行了建模。根据潜艇目标位置信息的不确定性,研究了潜艇目标位置信息的概率分布函数,采用Markov状态转移概率矩阵描述了潜艇目标位置信息变化的方法。其次,给出了基于贝叶斯理论的潜艇目标信息概率分布函数更新公式。再次,推导了舰载反潜直升机吊放声纳区域反潜最优策略,给出了舰载直升机吊放声纳区域反潜搜索算法。最后给出了典型案例,验证了反潜搜索策略的有效性。研究成果可为舰载反潜直升机吊放声纳区域反潜提供决策依据。     

侦察无人机作战效能评估准则研究*

在对有人驾驶飞机作战效能评估方法的分析研究基础上,提出了完整的侦察无人机作战效能评估指标体系。建立了作战效能的评估准则与数学模型,并对影响侦察效能的参数进行了分析。运用该方法对“全球鹰”和“捕食者”两种无人机的侦察效能指数进行了定量评估,结果验证了该评估准则的可用性。     

Asymmetric information and third-party intervention in civil wars

I study a two-period model of conflict with two combatants and a third party who is an ally of one of the combatants. The third party is fully informed about the type of her ally but not about the type of her ally’s enemy. In a signaling game, I find that if the third party is unable to give a sufficiently high assistance to her ally, then there exists a unique separating equilibrium in which the third party’s expected intervention causes her ally’s enemy to exert more effort than in the absence of third-party intervention; this worsens the conflict.