摘要：This paper investigates joint design and optimization of both low density parity check （LDPC） codes and M-algorithm based detectors including iterative tree search （ITS） and soft-output M-algorithm （SOMA） in multiple-input multiple-output （MIMO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

摘要：第四届设计北京博览会于2018年4月29日至5月2日在全国农业展览馆1号馆与3号馆隆重举行.我们将联动亚洲及欧美等地多家设计机构,同时集结国内新锐力量,共同策划一场汇聚多方表达的设计盛宴,带领大家走进一场融合艺术、设计与生活的策划之中.

摘要：Numerous Internet security incidents have shown that support from secure operating systems is paramount to fighting threats posed by modern computing environments. Based on the requirements of the relevant national and international standards and criteria, in combination with our experience in the design and development of the ANSHENG v4.0 secure operating system with high security level （hereafter simply referred to as ANSHENG OS）, this paper addresses the following key issues in the design of secure operating systems with high security levels： security architecture, security policy models, and covert channel analysis. The design principles of security architecture and three basic security models： confidentiality, integrity, and privilege control models are discussed, respectively. Three novel security models and new security architecture are proposed. The prominent features of these proposals, as well as their applications to the ANSHENG OS, are elaborated. Cover channel analysis （CCA） is a well-known hard problem in the design of secure operating systems with high security levels since to date it lacks a sound theoretical basis and systematic analysis approach. In order to resolve the fundamental difficulties of CCA, we have set up a sound theoretical basis for completeness of covert channel identification and have proposed a unified framework for covert channel identification and an efficient backward tracking search method. The successful application of our new proposals to the ANSHENG OS has shown that it can help ease and speedup the entire CCA process.

摘要：网络已经成为当下影响文化生态的重要媒介,网络文艺是网络生存和传播影响大众的重要存在。文章全面考察中国网络文艺的现状,认为网络文艺是呈现于网络媒介上的一切文艺样态的作品,网络文艺的主要形态包括视频类、音频类、文字类、游戏类等。在考察现状的基础上,选取代表性的重点,对网络文学、网剧和网络音乐等进行细致分析。为各类别网剧阐释概念、梳理创作现象,分析得失,提出发展网剧的针对性策略。

摘要：A design procedure for improving the efficiency of a transonic compressor blading was proposed based on a rapid generation method for three-dimensional blade configuration and computational meshes, a three-dimensional Navier-Stokes solver and an optimization approach. The objective of the present paper is to design a transonic compressor blading optimized only by selection of the locations of maximum camber and maximum thickness for the airfoils at different span heights and to study how do these two design parameters affect the blade performance. The blading configuration and the computational meshes can be obtained very rapidly for any given combination of maximum camber and maximum thickness. The computational grid system generated is used for the Navier-Stokes solution to predict adiabatic efficiency, total pressure ratio and flow rate. As a main result of the optimization, adiabatic efficiency was successfully improved.

摘要：自白派诗人陷入了这样一个困境 :一方面他们的幻觉和疯狂通过艺术得到解放 ,进入艺术境界使他们获得一种精神上的满足和不朽感 ,这自然有利于解除种种心理负担、治疗所患的精神疾病 ;另一方面他们在进行痛苦的艺术探索时也冒着生命的危险 ,因为他们的幻觉和疯狂有时会被某种艺术形式所定形 ,这样一来幻觉和疯狂对诗人本人来说就更为贴近了。自白诗既是一种调和的艺术又是一种抗拒的艺术。有的自白派诗人在创作的约束中发现了和平的、治疗性的解脱 ,有的则被自己具有同样约束力的创作推向危险的边缘。

摘要：二十世纪中国戏剧发生巨大变化,现代性因之成为发展的重要动力。本文试图从现代性与启蒙的关系,尤其是现代性与本土化的关系等角度说明,认识与研究中国戏剧的发展变化。因此,应该更多地注意到艺术本身出现的具有现代性意义的发展变化,它包括艺术更趋于自律,平民的艺术趣味得到更多肯定等等基于艺术层面的具有现代性精神内涵的变化。这些变化围绕着两个重要的维度展开,其一是中国戏剧开始了它对现代性的探求,与之相对应的另一方面则是源于传统的本土化倾向。几乎所有重要的变化均其于现代性与本土化的互动。只有准确理解二十世纪中国戏剧发展进程的现代性与本土化倾向,才能真正理解二十世纪中国戏剧。

摘要：文章在微支付机制基础上提出了一种新的网络广告点击支付模型,给出了该模型的多种实现方案。最后对方案的具体实现给出了建议。

摘要：建立了超燃冲压发动机二维进气道的优化设计模型 ,运用优化设计方法对三楔角外压和二楔角内压的混压式进气道进行了不同约束条件下的一维优化设计。运用数值方法对进气道的优化设计进行了二维验算 ,验证了优化设计模型及设计方法的正确性。在此基础上将数值计算方法应用于进气道的二维优化设计 ,进一步提高了进气道的性能。该方法可进一步推广应用于包含三维、真实气体流动的进气道优化设计当中。

摘要：北京师范大学在实现转型的过程中,从我国社会经济和教育发展的需要以及国际教师教育发展的基本趋势出发,就我国教师教育改革面临的一些重要问题进行了创新性研究,形成了较为完整的理论体系;积极推进教师教育模式多元化改革,其中以4+2为核心的教师培养模式改革,主动适应我国基础教育发展对高层次教师的迫切需求,在培养方式、课程设置、实践环节、指导方式、论文写作等方面进行了富有创意的探索,为我国基础教育高素质教师的培养探索出了新的路子。与此同时,还通过整合学校现有的各种资源,初步建立起了职前/职后、培养/培训一体化的教师终身教育体系,拓展和强化了教师教育的传统和特色。