基于天线阵方位变化的相位双差GNSS欺骗干扰检测算法研究*

GNSS欺骗干扰通常由单个天线发射,各个欺骗干扰信号到达接收机的角度相同,采用阵列天线接收时欺骗信号达到不同阵元的相位差包含了其角度信息,故可利用信号载波相位差进行欺骗干扰检测。相位双差检测算法通过比较不同卫星信号到达天线阵两阵元的相位差实现欺骗干扰的判别,但对于二元天线阵,其载波相位双差存在角度模糊,导致虚警概率较高,限制了算法的应用。针对这一问题,本文提出了基于天线阵方位变化的欺骗干扰检测算法,通过二元天线阵在不同方位估计信号的载波相位双差,进行多次判决,有效消除了角度模糊,降低检测的虚警概率,实现二元天线的载波相位双差检测。建立了仿真模型,并通过仿真计算分析验证了该方法的有效性。     

未来能量互联的关键设备——固态变压器

固态变压器作为能源互联网中实现能量转换和控制的关键设备,有很多方面需要进行深入研究,文章结合固态变压器的自身特点,对其主要发展的核心技术,包括基于SiC新型宽禁带材料的研制、基于SiC的固态功率器件和固态变压器设计与实现、固态变压器的先进控制策略研究等进行了详细阐述。     

An assessment of the ‘democratic’ coup theory

The Egyptian military's unconstitutional removal of President Mohamed Morsi has reignited a debate regarding the theory of the ‘democratic coup’. Though coups are almost invariably condemned, many political observers and a few scholars have recently argued that coups can act as catalysts for democratisation. This paper empirically assesses the democratic coup hypothesis for Africa. Multivariate analyses from 1952 to 2012 suggest that coups statistically improve a country's democratisation prospects. Extensions of the model show that coups appear to be likely precursors for democratisation in staunchly authoritarian regimes and have become less likely to end democracy over time, and that their positive influence has strengthened since the end of the Cold War. As of 2012, countries that have experienced a recent coup are expected to be four times more likely to witness a democratic transition than those that have remained coup-free.     

基于维修器材离散随机需求最佳库存量确定研究

结合装备维修器材保障工作,就维修器材离散随机需求最佳库存量确定进行研究,对其建模进行系统分析,结合修理厂维修器材最佳库存量进行实例计算,以指导维修器材最佳库存量的确定.     

NATO AS AN EXTERNAL DRIVER OF INSTITUTIONAL CHANGE IN POST‐COMMUNIST COUNTRIES

So far, economic analyses of NATO enlargement have been restricted to aspects of regional security while political analyses focused on indirect peace‐building effects on democracy in the first place. Our panel regressions for 25 post‐communist countries for the period from 1996 to 2008 reveal that direct incentives provided by NATO pre‐accession are important for broad‐based institutional development. Results are even more robust than for variables measuring EU pre‐accession or NATO membership effects. This supports the argument that NATO can act as a transformative power and should strengthen its political agenda.     

The Trust Paradox in Nuclear Smuggling

ABSTRACT

This article explores the paradox of trust in the largest nuclear smuggling operation involving highly enriched uranium (HEU) discussed in open source literature. In the first effort to understand the type, extent, and role of trust in nuclear smuggling enterprises, it draws from literature on trust development in legitimate businesses as well as criminal enterprises. Observed behavioral patterns in this case challenge traditional notions of the internal dynamics of temporary groups engaged in nuclear smuggling and operational realities of such activities. The article seeks to explain why individuals agree (and continue) to operate in this high-risk environment, unbound by close personal ties, without any effort to verify the background, motives, or qualifications of the fellow conspirators. It offers ways to advance current nonproliferation efforts in non-state actor interdiction by exploiting the environment of shallow trust in temporary groups.     

Reflections on Transparency and Monitoring under the 1993 United States-Russian Federation Highly Enriched Uranium Purchase Agreement

ABSTRACT

The 1993 Highly Enriched Uranium (HEU) Purchase Agreement between the United States and Russian Federation is often described as one of the world's most successful nuclear nonproliferation programs. In 2013, the two states achieved the agreement's major goals of downblending 500 metric tons of Russian weapon-origin HEU to low enriched uranium (LEU) and delivering all resultant LEU to the United States. At one time, the LEU delivered under the agreement generated nearly 10 percent of all electricity in the United States. The agreement achieved its nonproliferation goals through a unique government/industry partnership. Commercial executive agents contracted for the annual sale and delivery of downblended LEU, while the US and Russian governments exercised reciprocal transparency monitoring measures to demonstrate that all LEU delivered under the agreement was derived from Russian weapons-origin HEU, and that the same LEU was used for exclusively peaceful purposes in the United States. The commercial development, negotiations, and implementation of the agreement have been well documented. This article describes the scope of US transparency monitoring activities in Russian HEU processing facilities, as well as Russian monitoring in the United States. In addition, it discusses the results of twenty years of reciprocal transparency monitoring and data analysis, and outlines lessons learned that are potentially applicable to future transparency monitoring and verification regimes and similar cooperative efforts.     

Using container inspection history to improve interdiction logistics for illicit nuclear materials

Strengthening the United States' ability to prevent adversaries from smuggling nuclear materials into the country is a vital and ongoing issue. The prospect of additional countries, such as Iran, obtaining the know‐how and equipment to produce these special nuclear materials in the near future underscores the need for efficient and effective inspection policies at ports and border crossings. In addition, the reduction of defense and homeland security budgets in recent years has made it increasingly important to accomplish the interdiction mission with fewer funds. Addressing these complications, in this article, we present a novel two‐port interdiction model. We propose using prior inspection data as a low‐cost way of increasing overall interdiction performance. We provide insights into two primary questions: first, how should a decision maker at a domestic port use detection data from the foreign port to improve the overall detection capability? Second, what are potential limitations to the usefulness of prior inspection data—is it possible that using prior data actually harms decision making at the domestic port? We find that a boundary curve policy (BCP) that takes into account both foreign and domestic inspection data can provide a significant improvement in detection probability. This BCP also proves to be surprisingly robust, even if adversaries are able to infiltrate shipments during transit. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 433‐448, 2013     

Virtual War in the Ice Jungle: ‘We don't know how to do this’

The Cold War at sea expanded in many realms, including the frigid and treacherous waters of the Arctic Ocean. The US Navy pioneered these efforts with the visit of USS Nautilus to the North Pole in 1958. During the latter stages of the Cold War, however, Soviet naval strategists began to conceptualize the polar ice cap as a strategic asset for cloaking the operations of its nuclear missile submarines. As under-ice operations afforded the Soviet submarine fleet advantages of stealth, proximity to target and tighter lines of communications, both navies were forced to try to develop tactics for combat under these extremely complex and arduous conditions.     

新疆生产建设兵团教师教育的变迁与发展

新疆生产建设兵团成立以来,不仅担负着国家赋予的屯垦戍边职责,也担负着沉重的文化教育使命。回顾兵团教师教育30年的发展历程,兵团教师教育先后历经了初创期、成长期和发展期三个阶段。当前,兵团教师教育在办学指导思想,师资队伍建设、课程设置、人才培养模式上存在一系列问题。根据当前高等教育的发展趋势,今后兵团教师教育应坚持“师范性”与“学术性”并重的原则,走内涵发展之路,加强特色学科和专业建设,优化人才优化培养模式,改革教师教育课程体系,打造教师教育专业团队,推动兵团教师教育事业更好更快地发展。