Detecting clusters with increased mean using scan windows with variable radius

Applying spatiotemporal scan statistics is an effective method to detect the clustering of mean shifts in many application fields. Although several exponentially weighted moving average (EWMA) based scan statistics have been proposed, the existing methods generally require a fixed scan window size or apply the weighting technique across the temporal axis only. However, the size of shift coverage is often unavailable in practical problems. Using a mismatching scan radius may mislead the size of cluster coverage in space or delay the time to detection. This research proposed an stEWMA method by applying the weighting technique across both temporal and spatial axes with variable scan radius. The simulation analysis showed that the stEWMA method can have a significantly shorter time to detection than the likelihood ratio-based scan statistic using variable scan radius, especially when cluster coverage size is small. The application to detecting the increase of male thyroid cancer in the New Mexico state also showed the effectiveness of the proposed method.     

Reflections on the Sociology of Security and Surveillance in the Study of Immigration

In the last decade, sociologists have begun to address major issues associated with the rise of security and surveillance. My work suggests the ways in which a sociology of surveillance can contribute to the study of immigration and how, in turn, work on immigration can contribute to this new and growing field.     

认识·素质·艺术──浅议舆论监督对新闻工作者的基本要素

新闻工作者为提高新闻舆论监督水平，一要走出两种认识误区，即舆论监督无限制论和舆论监督绝对独立论的误区；二要提高政治思想素质，具有高度的政治责任感和正确的出发点，并严守新闻纪律和职业道德；三要讲究策略艺术，求真求实，业务熟练。     

Freedom as Mobility: Implications of the Distinction between Actual and Potential Travelling

This paper defines mobility as the potential transport of humans and explores the mobility aspect of freedom. Freedom as mobility is composed both of opportunities to travel when and where one pleases and of the feasibility of the choice not to travel. The essay further analyses the implications for the idea of freedom as mobility of distinguishing between actual and potential travel. It is also shown how mobility as a right is challenged by a central feature of democracy – namely, respect for unanimity – and how tracks left by travellers can be exploited for surveillance and control. Moreover, mobility leads to a potential absence and thus uncertainty. The paper evaluates how alternative responses to this problem have widely different consequences for the experience of freedom as mobility.     

基于利益相关者视角下的食品安全问题研究

食品安全问题关系到人民群众的切身利益，关系到我国和谐社会的构建，已经成为一项公共政策问题。用利益相关者视角去分析研究，更能够透彻明白地显现出各个部门和群体的职责和责任，有利于分清各个主体的权责解决食品安全问题，有利于保护人民群众的生命健康，有利于构建食品安全体系。     

The Joy of Teaching Current Events

Set during the immediate years after the creation of the Berlin Wall, this case study focuses on the East German Ministry for State Security (MfS) and its secret police force known as the Stasi. Students, acting as West German spies working in East Berlin, recover secret documents used by the East German government in its efforts to maintain power, control, and stability over both its citizens and Western Europe. This activity uses higher-level Bloom's taxonomy as students evaluate, compare, and contrast documents for importance and relevance. Each document represents measures commonly used by Eastern Bloc nations throughout the Cold War, providing students with creative insight on how domestic and foreign espionage played a vital role in the struggle between Soviet communism and American democracy. This lesson is an example of how to use the case study approach.     

False security or greater social inclusion? Exploring perceptions of CCTV use in public and private spaces accessed by the homeless

It has been well documented that owing to the vulnerability inherent in their situation and status, the homeless experience high rates of harassment and criminal victimization. And yet, the question of whether CCTV surveillance of public and private spaces – so frequently viewed by the middle classes as a positive source of potential security – might also be viewed by the homeless in similar ways. Within the present paper, I address this issue by considering the possibility that CCTV might be seen by some homeless men and women as offering: a) a measure of enhanced security for those living in the streets and in shelters, and; b) to the extent that security is conceived of as a social good, the receipt of which marks one as a citizen of the state, a means by which they can be reconstituted as something more than ‘lesser citizens’. To test these ideas, I rely on data from interviews conducted with homeless service users, service providers for the homeless, and police personnel in three cities. What is revealed is a mixed set of beliefs as to the relative security and meaning of CCTV.     

对空监视情报雷达宽带技术应用研究

对一种对空监视情报雷达采用宽带技术提高目标监视、跟踪性能进行了分析和仿真,研究了多径传播引起的分裂波瓣,其凹口以及峰值所在角度,并且对多频点的雷达威力进行了合成分析.结果表明,适当增加雷达系统带宽,可以大大减少由于多路径传播造成的波瓣分裂影响,进而比较显著地提高情报雷达的目标监视和跟踪性能.其结果对于要求具有自动检测和跟踪的对空情报雷达特别重要.     

A Comparison of Likelihood-Based Spatiotemporal Monitoring Methods Under Non-Homogenous Population Size

This article discusses the spatiotemporal surveillance problem of detecting rate changes of Poisson data considering non-homogenous population sample size. By applying Monte Carlo simulations, we investigate the performance of several likelihood-based approaches under various scenarios depending on four factors: (1) population trend, (2) change magnitude, (3) change coverage, and (4) change time. Our article evaluates the performance of spatiotemporal surveillance methods based on the average run length at different change times. The simulation results show that no method is uniformly better than others in all scenarios. The difference between the generalized likelihood ratio (GLR) approach and the weighted likelihood ratio (WLR) approach depends mainly on population size, not change coverage, change magnitude, or change time. We find that changes associated with a small population in time periods and/or spatial regions favor the WLR approach, but those associated with a large population favor the GLR under any trends of population changes.     

Aspects on the control of false alarms in statistical surveillance and the impact on the return of financial decision systems

In systems for online detection of regime shifts, a process is continually observed. Based on the data available an alarm is given when there is enough evidence of a change. There is a risk of a false alarm and here two different ways of controlling the false alarms are compared: a fixed average run length until the first false alarm and a fixed probability of any false alarm (fixed size). The two approaches are evaluated in terms of the timeliness of alarms. A system with a fixed size is found to have a drawback: the ability to detect a change deteriorates with the time of the change. Consequently, the probability of successful detection will tend to zero and the expected delay of a motivated alarm tends to infinity. This drawback is present even when the size is set to be very large (close to one). Utility measures expressing the costs for a false or a too late alarm are used in the comparison. How the choice of the best approach can be guided by the parameters of the process and the different costs of alarms is demonstrated. The technique is illustrated by financial transactions of the Hang Seng Index.