功率谱杂散对LFMCW雷达性能的限制

为使线性调频连续波 (L FMCW)雷达能获得理论上的高测距精度和距离分辨力 ,在工程应用中对其性能的限制因素倍受关注 ,其中发射信道的非线性放大失真将引起 L FMCW信号功率谱产生边带杂散 ,是限制 L FMCW雷达测距精度和距离分辨力的重要因素之一。依据 L FMCW雷达回波功率谱特性 ,从工程应用角度分析了这种信号功率谱边带杂散对 L FM-CW雷达测距精度和距离分辨力的影响 ,为实现高性能系统设计 ,确定合理的实施方案和相关的技术指标及后续的校正处理提供了理论依据。     

Power and influence in post-secession South Sudan: A leadership perspective on nation-building

ABSTRACT

Following South Sudan's secession in 2011, the country faced significant political, social and economic challenges. The country emerged from a long andarduous nation-building journey, including almost 50 years of violent conflict, that would continue after declaring independence. This nation-building process would suffer a significant set-back in December 2013 when the most recent civil war broke out. This article provides a new perspective on South Sudan's nation-building trajectory that tends towards violence and complicates peace-building. It does so by utilising the leadership process approach from the Leadership Studies literature. While popular literature and commentary tends to fault the South Sudanese elite for the current crisis, there has not been a systematic effort to understand the leadership challenge and its role in conflict, peace and nation-building in South Sudan. In this article, South Sudan's nation-building process and its three primary components of (a) identity construction, (b) statehood and (c) collective will and responsibility, are analysed from a leadership perspective, focusing on issues of power and influence. The conclusion is reached that South Sudan's nation-building has been and will likely continue to trend towards a violent process due to a leadership process that lacks mutuality and is founded on insufficient sources of power.     

Securitising humanitarian assistance and post-conflict reconstruction in Africa: A critical review of South Africa's new defence policy

The South African Defence Review 2014 is the country's new defence policy. The Review, which is expected to steer South African defence policymaking for the next few decades, discusses in detail the role of the South African National Defence Force (SANDF) in peace missions in Africa and proposes the direct involvement of the country's soldiers in both military and civilian tasks, from peacekeeping to humanitarian assistance, post-conflict reconstruction and development. This paper contains a critical review of the Review with regard to South Africa's envisaged contribution to regional and continental peace and stability. It is argued that humanitarian assistance and post-conflict reconstruction should not be securitised and that the SANDF should only be tasked with peacekeeping and the establishment of stability and security in fragile in-conflict and post-conflict settings. The humanitarian work should be left to humanitarian and aid agencies, while reconstruction and development should be left to organisations such as the New Partnership for Africa's Development, continental and international development organisations, and local actors.     

基于模型诊断的集合逻辑运算法计算最小碰集

在基于模型的故障诊断仿真系统的诊断流程中,由最小冲突集计算最小碰集是整个流程中的关键步骤。针对现有计算最小碰集方法中存在的缺陷,提出了运用集合逻辑运算法计算最小碰集,将冲突集表示为集合的逻辑"与"、逻辑"或"运算,通过其运算法则进行运算简化,可得到全部的最小碰集。该方法具有简单有效、数据结构简单、计算简便快捷和易于程序实现等优点。最后通过实例计算,验证了该算法的正确性、简单性和高效性。     

频率步进雷达高分辨距离像解模糊方法研究

针对频率步进雷达中存在的高分辨距离像模糊现象,通过分析其本质原因--周期延拓引起循环移位,提出了一种等效混频解距离像模糊的新方法,并给出了等效混频本振频率的选择范围.通过仿真实验验证了该方法的有效性.     

Building peace from the margins in Somalia: The case for political settlement with Al-Shabaab

The prevailing discourse in Mogadishu among the federal government of Somalia and the international community is that Al-Shabaab is no longer relevant in contemporary Somali political landscape. In the language of the government, Al-Shabaab is like a lost crocodile thrown out from the river. In the lexicon of the international community, Al-Shabaab is gradually receding. In fact, Al-Shabaab is actually puissant and potent in terms of social, political and military capabilities; not just in Somalia, but also in the wider East Africa region. Why is Al-Shabaab resilient and resistant? Why is it even more effective than the federal government? To answer these questions, this article reveals how Al-Shabaab is increasingly more legitimate than the federal government. In conclusion, the article proposes that negotiated settlement with the insurgency movement could lead to peace in war-torn southern Somalia.     

Dynamics in pastoral resource management and conflict in the Borana rangelands of southern Ethiopia

Based on primary and secondary data, this paper provides a qualitative account of current changes in the pattern of natural resource management as a result of resource degradation and conflict in the Borana rangelands of southern Ethiopia. Population pressure, recurrent drought and the depleted carrying capacity of pastoral resources, as well as the encroachment of neighbouring ethnic groups, present the Borana community with a significant challenge. The diminishing resilience of traditional politico-judicial institutions under the famous Gada system often result in the rise of new forms of land use such as farming and private enclosures, which compete with the traditional communal tenure system. The gradual collapse of traditional norms and value systems and the apparent inefficiency in the formal administrative structures have exacerbated the problems of resource degradation and conflict between multiple resource-users.     

高频地波超视距雷达述评

高频(HF)地波超视距雷达(GW-OTHR)利用雷达波束绕地表面衍射作用,能探测视距外的舰船、低空飞机和巡航导弹,不仅覆盖面积大、费用低,能弥补常规微波雷达低空盲区和天波超视距雷达的近距盲区,也无需注意电离层的变化,且可反隐身、抗反辐射导弹(ARM),因而在许多国家的国民经济和国防领域中得到了广泛的应用。论述了地波沿海面传播的特性和探测能力,并对超视距雷达的发展和应用进行了介绍。     

论翻译中的文化依附

文化依附问题在翻译中至关重要。本文用若干有说服力的译例从文化偶合、文化并行、文化冲突、文化空缺四个方面介绍分析了在翻译过程中如何处理文化依附矛盾的问题。     

基于随机搜索策略的中继卫星调度方法

高质量的调度方案不仅能满足用户的需求,还能为中继卫星系统的计划编制提供科学的决策手段和依据。针对日益多样化的用户需求,采用全新的中继卫星调度应用模式,允许用户提交多个可以滑动的时间窗口。面向这种调度模式,考虑中继业务中任务调度的灵活性和任务间的冲突,构建考虑多滑动窗口的中继卫星调度模型,并设计基于随机搜索策略的中继卫星调度算法。算法包括任务资源匹配与邻域生成、可用时间段生成、任务冲突分析、邻域搜索与冲突消解以及资源与任务集更新5个算子。通过仿真实验将该算法与基于时间自由度的启发式算法进行对比,验证了算法的有效性。