压缩感知稀疏表示在雷达目标识别中的应用

高分辨距离像(HRRP)目标识别算法很多,在其利用高分辨距离像蕴含的目标结构信息的同时,也需要面对数据量巨大的难题。事实上,尽管高分辨距离像数据量巨大,但却是稀疏的,然而利用其稀疏特性进行识别的方法却不多。为此,提出了一种基于压缩感知稀疏表示方法实现目标识别的算法。该算法首先采用遗传正交匹配追踪（OMP）算法对一维距离像训练样本进行稀疏分解以获得类别字典,然后根据类别字典分析测试样本的重构误差实现目标识别。仿真实验证明,所提算法简捷、识别率更高,相较于常规算法识别率提高最多可达20%,并且在受到噪声干扰情况下依然能够稳健地识别目标。     

Nash consistent representation of effectivity functions through lottery models

Effectivity functions for finitely many players and alternatives are considered. It is shown that every monotonic and superadditive effectivity function can be augmented with equal chance lotteries to a finite lottery model—i.e., an effectivity function that preserves the original effectivity in terms of supports of lotteries—which has a Nash consistent representation. The latter means that there exists a finite game form which represents the lottery model and which has a Nash equilibrium for any profile of utility functions satisfying the minimal requirement of respecting first order stochastic dominance among lotteries. No additional condition on the original effectivity function is needed.     

Shopping context and consumers’ mental representation of complex shopping trip decision problems

Depending on the shopping context, consumers may develop different mental representations of complex shopping trip decision problems to help them interpret the decision situation that they face and evaluate alternative courses of action. To investigate these mental representations and how they vary across contexts, the authors propose a causal network structure that allows for a formal representation of how context-specific benefits requirements affect consumers’ evaluation of decision alternative attributes. They empirically test hypotheses derived from the framework, using data on consumers’ mental representations of a complex shopping trip decision problem across four shopping contexts that differ in terms of opening hour restrictions and shopping purpose, and find support for the proposed structure and hypotheses.     

旅游目的地形象内涵及其建构过程解析

从文化的角度来看,旅游乃是借助符号的表征功能来传达意义的人类行为。旅游目的地形象是一种经由符号的表征功能而形成的为旅游社群所＂共享的意义＂。基于此,尝试一种全新的视角——表征,来重新审视旅游目的地形象的内涵及其建构过程,发现旅游目的地形象是一种具有社会、文化、历史3个层面的概念,并具有以下特征：典型的符号学意义、群体共享性和差异性;社会根源性和规范说明性;相对稳定性和长期动态性。旅游目的地形象的建构过程本质上是符号表征功能的运作,而旅游目的地形象建构的意义就在于它能规范和组织旅游社群内的旅游活动。     

Khatri-Rao积变换下的离格信号DOA估计

当存在离格信号时,基于稀疏表示的波达角（DOA）估计算法性能损失严重。为解决这个问题,在对接收数据协方差矩阵进行Khatri-Rao积变换的基础上,推导了离格信号网格偏离量与紧邻信号原子系数之间的关系,提出了一种单一离格信号DOA估计方法。为提高对邻近离格信号DOA的估计性能,利用矩阵的广义逆性质提出了基于多原子系数的联合估计方法。仿真实验表明,单一离格信号DOA估计方法在低信噪比下有较好的性能,联合估计方法在高信噪比条件下对邻近离格信号DOA有较高的估计精度,同时所提算法估计性能几乎不受网格划分间距的影响,可以通过增大网格间距降低算法运算量。相关研究对阵列天线DOA估计具有一定的参考价值。     

A social representation approach to facilitating adaptive co-management in mountain destinations managed for conservation and recreation

Mountain destinations are often managed not only to support tourism and recreation but also to maintain a range of sensitive ecological processes and services. Resource use and management activities in mountain destinations are manifestations of various representations of mountain landscapes that may contribute to tension and conflicts, or collaboration and learning between stakeholders of mountain destinations. Adaptive co-management (ACM) that adopts a social learning model to forge collaborative natural resource management provides one approach to managing complex and dynamic social-ecological systems in mountain destinations. Social representations (SR) theory, as a theory of social knowledge and social change, offers one theoretical lens with which to gain insights into the representations that different stakeholders ascribe to mountain landscapes and to assist in developing functioning ACM. The utility of SR theory for ACM arrangements is examined using a case study that explores the representations of the mountain landscape within Yushan National Park (YNP) in Taiwan from the perspectives of three resource user groups: committed mountaineers, professional guides, and mountain tourists. The study findings are used to demonstrate how the processes of representations and dialogical antinomies embedded in representations can impede or facilitate stakeholder interactions in ACM.     

RISK‐MINIMIZATION FOR LIFE INSURANCE LIABILITIES WITH DEPENDENT MORTALITY RISK

In this paper, we study the pricing and hedging of typical life insurance liabilities for an insurance portfolio with dependent mortality risk by means of the well‐known risk‐minimization approach. As the insurance portfolio consists of individuals of different age cohorts in order to capture the cross‐generational dependency structure of the portfolio, we introduce affine models for the mortality intensities based on Gaussian random fields that deliver analytically tractable results. We also provide specific examples consistent with historical mortality data and correlation structures. Main novelties of this work are the explicit computations of risk‐minimizing strategies for life insurance liabilities written on an insurance portfolio composed of primary financial assets (a risky asset and a money market account) and a family of longevity bonds, and the simultaneous consideration of different age cohorts.     

Settler colonialism,Indigenous cultures,and the promotional landscape of tourism in Ontario,Canada's ‘near North’

ABSTRACT

Settler colonialism relies upon a logic of elimination that strives to dissolve Indigenous culture and title to ancestral lands. In Canada, settler colonialism has steered not only oppressive state policy directions, but also settler narratives that essentialize and displace Indigenous Peoples and cultural connections to land. Tourism is an especially potent social force through which such settler stories can be perpetuated and resisted. The purpose of this paper is to analyze how Indigenous culture is portrayed in the tourism promotional landscape of Ontario's ‘near north’, a rural leisure landscape for nature enthusiasts and second-home owners. While Anishinaabeg and Haudenosaunee First Nations have inhabited this area for generations, their cultural presence is often marginalized in development discourses, both historical and contemporary. Our study draws upon critical discourse analysis of websites produced by stakeholders associated with three case study sites – a Provincial Park, an annual cranberry Festival, and a major casino operation – to understand both the limits and opportunities of tourism in relation to maintaining and revitalizing Indigenous culture. In so doing, our paper contributes to critiques of settler colonial power relations and how these infiltrate tourism, and identifies pathways for disrupting the erasure of Indigenous cultures in tourism.     

A bivariate infinitely divisible law for modeling the magnitude and duration of monotone periods of log‐returns

The focus of this article is modeling the magnitude and duration of monotone periods of log‐returns. For this, we propose a new bivariate law assuming that the probabilistic framework over the magnitude and duration is based on the joint distribution of (X,N), where N is geometric distributed and X is the sum of an identically distributed sequence of inverse‐Gaussian random variables independent of N. In this sense, X and N represent the magnitude and duration of the log‐returns, respectively, and the magnitude comes from an infinite mixture of inverse‐Gaussian distributions. This new model is named bivariate inverse‐Gaussian geometric ( in short) law. We provide statistical properties of the model and explore stochastic representations. In particular, we show that the is infinitely divisible, and with this, an induced Lévy process is proposed and studied in some detail. Estimation of the parameters is performed via maximum likelihood, and Fisher's information matrix is obtained. An empirical illustration to the log‐returns of Tyco International stock demonstrates the superior performance of the law compared to an existing model. We expect that the proposed law can be considered as a powerful tool in the modeling of log‐returns and other episodes analyses such as water resources management, risk assessment, and civil engineering projects.     

Shining light on the darkness. Placing tourists within North Korean tourism. Comment on: Desiring the dark: ‘A taste for the unusual’ in North Korean tourism?

Few studies exist of tourism in North Korea. Many passing references to tourism have been distanced from actual tourists. Visiting North Korea is a form of moral political tourism that has no relationship to dark tourism or fantasy, but represents tourist interest in seeking to discover a ‘real’ North Korea that is distinct from hegemonic political narratives from outside or inside the country. Tourism is associated with the need to evaluate and reconsider political orthodoxies and ideologies, and discover an everyday environment.