采用高分辨率雷达的自动目标识别系统

本文提出了一种利用雷达传感器观测值对飞机目标联合跟踪和识别的系统。文中假设用于估计目标方向和识别目标的数据源高于分辨率雷达的距离剖面图序列。在包括目标数目以及它们的位置、方向和目标类型和完整的参数空间上运用后验分布完成推理判断。算法严格地依赖于适当地传感器和目标模型，从距离剖面图的似然值可得出目标方向，由目标动态确定目标方向的先验值。给出了高分辨率雷达数据的确定性模型和随机模型，对确定性模型研究了     

在天线阵列方向图合成中运用遗传算法降低旁瓣

给出了一种用任意几何结构的天线阵列方向图合成的简单灵活的遗传算法（ＧＡ）。与运用二进制编码和二进制交叉的常规遗传算法所不同的是，这种方法直接用复数染色体来代表阵列激励加权矢量，而且还在没胶叉址的情况下运用十进制线性交叉。与常规的遗传算法相比，该算法具有以下几个优点：给出了问题的简单明了的表示，简化了染色体的建立过程，完全避免了二进制编码和码解，因而简化了软件编程，减少了ＣＰＵ时间，该方法还使我们能     

用于NASA局长期气球计划的低成本TDRSS通信设备

ＮＡＳＡ研制的新ＴＤＲＳＳ转发器和射频地面支持设备，使一系列低预算ＮＡＳＡ计划可以利用ＴＤＲＳＳ的通信业务。由于采用了当前先进技术，有些则是尖端技术，使这些新设备为用户提供了许多先进特性，而成本仍比以前任何一种设计方案低。     

波导喇叭理论的修正

许多作者已全面分析过波导喇叭，对于中高增益喇叭各种理论方法获得的结果基本一致。不过，对于低增益喇叭，用近似法来计算口径场不能获得精确的结果，会导致增益的误差。本文避开最通用的近似法，描述了一种修正后的分析方法。文中运用了１２ｄＢ喇叭的实验测量结果来证实为种理论。     

The NASA Astrobiology Roadmap

The NASA Astrobiology Roadmap provides guidance for research and technology development across the NASA enterprises that encompass the space, Earth, and biological sciences. The ongoing development of astrobiology roadmaps embodies the contributions of diverse scientists and technologists from government, universities, and private institutions. The Roadmap addresses three basic questions: How does life begin and evolve, does life exist elsewhere in the universe, and what is the future of life on Earth and beyond? Seven Science Goals outline the following key domains of investigation: understanding the nature and distribution of habitable environments in the universe, exploring for habitable environments and life in our own solar system, understanding the emergence of life, determining how early life on Earth interacted and evolved with its changing environment, understanding the evolutionary mechanisms and environmental limits of life, determining the principles that will shape life in the future, and recognizing signatures of life on other worlds and on early Earth. For each of these goals, Science Objectives outline more specific high-priority efforts for the next 3-5 years. These 18 objectives are being integrated with NASA strategic planning.     

A culture-independent survey of the bacterial community in a radon hot spring

Paralana is an active, radon-containing hot spring situated in a region of South Australia's Flinders Ranges with a long history of hydrothermal activity. Our aim was to determine the bacterial composition of Paralana using a culture-independent, 16S rRNA-based technique. The presence of a diverse bacterial community was strongly suggested by the large number (approximately 180) of different ribotypes obtained upon analysis of nine hot spring samples. DNA sequencing of Paralana 16S rRNA genes corroborated this observation, identifying representatives of seven confirmed and two candidate divisions of the domain Bacteria. These included Cyanobacteria, Proteobacteria (both beta and delta subdivisions), the Cytophaga-Flexibacter-Bacteroides group, Low G + C Gram-positives, Nitrospira, green non-sulfur bacteria, green sulfur bacteria, OP8, and OP12. No known ionizing radiation-resistant Bacteria were identified. Only one Paralana 16S rRNA sequence type (recombinant B5D) was homologous to a sequence previously identified from a radioactive environment.     

Genetic modification and selection of microorganisms for growth on Mars

Genetic engineering has often been suggested as a mechanism for improving the survival prospects of terrestrial microoganisms when seeded on Mars. The survival characteristics that these pioneer microorganisms could be endowed with and a variety of mechanisms by which this can be achieved are discussed, together with an overview of some of the potential hurdles that must be overcome. Also, a number of biologically useful properties for these microorganisms are presented that could facilitate the initial human colonisation and ultimately the planetary engineering of Mars.     

NASA spinoffs to bioengineering and medicine

Through the active transfer of technology, the National Aeronautics and Space Administration (NASA) Technology Utilization (TU) Program assists private companies, associations, and government agencies to make effective use of NASA's technological resources to improve U.S. economic competitiveness and to provide societal benefit. Aerospace technology from areas such as digital image processing, space medicine and biology, microelectronics, optics and electrooptics, and ultrasonic imaging have found many secondary applications in medicine. Examples of technology spinoffs are briefly discussed to illustrate the benefits realized through adaptation of aerospace technology to solve health care problems. Successful implementation of new technologies increasingly requires the collaboration of industry, universities, and government, and the TU Program serves as the liaison to establish such collaborations with NASA. NASA technology is an important resource to support the development of new medical products and techniques that will further advance the quality of health care available in the U.S. and worldwide.