基于射频指纹技术的卫星信号个体识别方法

现有射频指纹识别研究主要集中于射频指纹产生及提取的通信机理,忽略了实际应用中信号采集数据的清洗筛分、识别算法模型的效率等工程性问题。为此,分析了卫星通信号的载波信息提取的原理与方法,并针对现有射频指纹方法的不足,围绕卫星信号识别领域,利用海量采集的射频指纹数据,深入研究基于自组织神经网络的射频指纹识别算法,提出了对应的算法模型,并与现有常见的无监督算法进行了比较。结果表明,所提方法可以取得更优的算法聚类效果和时间开销,可作为设计实现卫星频谱管理系统的基础。     

Investigating the gap between citizens' sustainability attitudes and food purchasing behaviour: empirical evidence from Brazilian pork consumers

Consumers worldwide are increasingly concerned with sustainable production and consumption. Recently, a comprehensive study ranked 17 countries in regard to their environmentally friendly behaviour among consumers. Brazil was one of the top countries in the list. Yet, several studies highlight significant differences between consumers' intentions to consume ethically, and their actual purchase behaviour: the so‐called ‘Attitude‐Behaviour Gap’. In developing countries, few studies have been conducted on this issue. The objective of this study is therefore to investigate the gap between citizens' sustainability‐related attitudes and food purchasing behaviour using empirical data from Brazil. To this end, Brazilian citizens' attitudes towards pig production systems were mapped through conjoint analysis and their coexistence with relevant pork product‐related purchasing behaviour of consumers was investigated through cluster analysis. The conjoint experiment was carried out with empirical data collected from 475 respondents surveyed in the South and Center‐West regions of Brazil. The results of the conjoint analysis were used for a subsequent cluster analysis in order to identify clusters of Brazilian citizens with diversified attitudes towards pig production systems, using socio‐demographics, attitudes towards sustainability‐related themes that are expected to influence the way they evaluate pig production systems, and consumption frequency of various pork products as clusters' background information. Three clusters were identified as ‘indifferent’, ‘environmental conscious’ and ‘sustainability‐oriented’ citizens. Although attitudes towards environment and nature had indeed an influence on citizens' specific attitudes towards pig farming at the cluster level, the relationship between ‘citizenship’ and consumption behaviour was found to be weak. This finding is similar to previous research conducted with European consumers: what people (in their role of citizens) think about pig production systems does not appear to significantly influence their pork consumption choices. Improvements in the integrated management of this chain would better meet consumers' sustainability‐related expectations towards pig production systems.     

浅述出入境检验检疫与非传统安全问题的治理

在当前全球经济贸易自由化和区域经济一体化不断深入的趋势下,经济金融动荡、资源能源短缺、贸易保护主义、自然生态环境恶化、传染病大规模暴发、产品质量与食品安全以及生物恐怖主义等在内的诸多非传统安全问题对我国的经济社会发展和公共安全构成了重大威胁。而科学发展观理论的提出,正是重点针对上述问题,以确保全面协调可持续发展,构建以人为本的和谐社会。出入境检验检疫是我国参与全球化秩序最早也是融入最充分的工作体系之一,本文在对非传统安全问题内涵、成因及传播的一般规律进行解释的基础上,分析了非传统安全问题与出入境检验检疫之间的内在联系,并结合笔者个人思考,给出了在科学发展观的指导下,出入境检验检疫如何积极参与我国非传统安全问题治理的建议。     

城市道路景观设计的几点意见

城市道路的景观设计既是城市的特色也是交通安全的重要影响因素,本文通过介绍山水东路以及金石南路两条道路的景观设计,就城市道路的交通组成研究了对景观设计的要求,城市道路景观对交通的影响,提出了城市道路景观设计与交通协调的内容与方法。结果表明,城市道路的景观设计能调节道路使用者的心理状态,对改善交通状况、减少交通事故的发生有重要作用。     

Opinion convergence in location: A spatial version of the Delphi method

This paper proposes a modified version of the Delphi method, starting from the assumption that in many situations the convergence of opinions can be considered in a spatial context. The Spatial Delphi we suggest is based, like the classical Delphi, on the judgments of experts, and it is useful in the consultations for decision and/or forecast purposes, provided that they concern matters of spatial location. The basis for the questionnaire is a map, on which each expert provides, as answer(s), one or more opinion-points, i.e., locations that, according to their opinion, are best for a specific purpose. We propose a method for narrowing the area of convergence along a multi-step procedure so that the final result of the consultation is a small portion of the initial territory with respect to the initial area considered. Besides a simulation study, we report also a prototype application with a panel of twelve experts.     

Formal and informal external linkages and firms�� innovative strategies. A cross-country comparison

Firms increasingly rely upon external actors for their innovation process. Interaction with these actors may occur formally (i.e. through a collaboration agreement) or informally (i.e. external actors acts as sources of information). We analyze the reasons why firms consider it to be important to develop formal and informal external linkages in the innovation process by looking at the role played by firms’ innovative strategies and by taking into account the possibility that a complementarity or substitutive relationship might exist between formal and informal linkages. Data are from the Third Community Innovation Survey (CIS 3), where we have access to firm level micro-data from Sweden, Norway, the Netherlands and the UK.     

Abatement and Allocation in the Pilot Phase of the EU ETS

We use historical industrial emissions data to assess the level of abatement and over-allocation that took place across European countries during the pilot phase (2005–2007) of the European Union Emission Trading Scheme. Using a dynamic panel data model, we estimate the counter factual (business-as-usual) emissions scenario for EU member states. Comparing this baseline to allocated and verified emissions, we find that both over-allocation and abatement occurred, along with under-allocation and emissions inflation. Over the three trading years of the pilot phase we find over-allocation of approximately 280 million EUAs and total abatement of 247 Mt CO₂. However, we calculate that emissions inflation of approximately 73 Mt CO₂ also occurred, possibly due to uncertainty about future policy design features.     

中国省域劳动就业影响因素的空间计量分析

利用2000-2009年中国29个省级单位数据建立空间计量模型对影响劳动就业的各因素及其空间效应进行检验分析。结果显示:省际劳动就业存在显著的空间相关性,邻近省域就业的溢出效应对本省具有正向影响,且该效应从东部到西部地区呈阶梯状依次递减,东部地区就业较中西部地区具有更强的区间联动性。省域技术进步、财政支出、市场化和产业结构优化无论从全国层面还是地区层面均对劳动就业具有显著的促进作用,且财政支出对中西部就业的影响明显大于东部地区;城市化与实际工资对东部就业影响不显著,但能够显著促进中西部地区就业增长。促进区间联动、加快市场化、城市化和产业结构优化步伐、完善和优化财政支出结构是增加就业的重要举措。     

Do interest groups affect US immigration policy?

While anecdotal evidence suggests that interest groups play a key role in shaping immigration policy, there is no systematic empirical analysis of this issue. In this paper, we construct an industry-level dataset for the United States, by combining information on the number of temporary work visas with data on lobbying activity associated with immigration. We find robust evidence that both pro- and anti-immigration interest groups play a statistically significant and economically relevant role in shaping migration policy across sectors. Barriers to migration are lower in sectors in which business interest groups incur larger lobbying expenditures and higher in sectors where labor unions are more important.