A comprehensive survey on computer vision based concepts,methodologies, analysis and applications for automatic gun/knife detection

The ability to detect gun and gun held in hand or other body parts is a typical human skill. The same problem presents an imperative task for computer vision system. Automatic observer independent detection of hand held gun or gun held in the other body part, whether it is visible or concealed, provides enhance security in vulnerable places and initiates appropriate action there. Compare to the automatic object detection systems, automatic detection of gun has very few successful attempts. In the present scope of this paper, we present an extensive survey on automatic detection of gun and define a taxonomy for this particular detection system. We also describe the inherent difficulties related with this problem. In this survey of published papers, we examine different approaches used in state-of-the-art attempts and compare performances of these approaches. Finally, this paper concludes pointing to the possible research gaps in related fields.     

铁路反恐视频监控系统方案探究

本文通过分析反恐视频监控的需求，研究了普通红外线摄像机和激光摄像机的性能、铁路通信传输网通道容量和视频占用的资源量，推荐反恐视频监控方案采用数字激光摄像机。     

A terrain risk assessment method for military surveillance applications for mobile assets

This study proposes an analytical and flexible terrain risk assessment method for military surveillance applications for mobile assets. Considering the risk as the degree of possibility of insurgent presence, the assessment method offers an efficient evaluation of risk in the surrounding terrain for military combat operating posts or observation posts. The method is designed for unmanned aerial vehicles as the surveillance assets of choice to improve the effectiveness of their use. Starting with the area map and geographical data, the target terrain is first digitized for space representation. Then the data of nine geographical parameters are used to formulate five contributing risk factors. These factors are incorporated in an analytical framework to generate a composite map with risk scores that reveal the potential high-risk spots in the terrain. The proposed method is also applied to a real-life case study of COP Kahler in Afghanistan, which was a target for insurgent attacks in 2008. The results confirm that when evaluated with the developed method, the region that the insurgents used to approach COP Kahler has high concentration of high-risk cells.     

低开销负载均衡的改进型TORA协议

针对无线传感器网络拓扑快速变化、链路易拥塞断开，存在路由开销大、负载不均衡、网络生命周期短等问题，提出低开销负载均衡的改进型TORA（TORA-p）。通过定义网络变化率参数，自适应调整互联网封装协议（IMEP）中OBM包的最大重发次数，减少不必要的路由维护开销；同时，结合MAC层信息，定义链路可用性优化选路方式，自动平衡网络负载，避免关键路径和节点负载过重而过早死亡和断开。使用truetime2.0平台设定特定的仿真环境，对TORA-p算法的性能进行了详细比较分析，结果表明：TORA-p均衡了网络负载，提升了网络生命周期，同时也减少了路由开销和延时，展现出了较好的数据传输能力。     

Too big to surveil: the fourth amendment illuminated by ‘modern lights’ and shadowed by obsta principiis in a post-Carpenter world concerned with privacy

The Fourth Amendment to the U.S. Constitution functions as a shield against excess governmental or police power by prohibiting unreasonable searches and seizures. Since its ratification, legal challenges have tempered this shield by frequently disputing the application of investigative processes and tools, including those that bypass the traditional – and simpler – analysis that focused on physical trespass. But recent technological advancements have prompted novel challenges and have forced the U.S. Supreme Court to adopt a parallel inquiry that evaluates society’s expectations of privacy as an alternate path to invoke the Fourth Amendment’s protections apart from any physical trespass. As revolutionary technology continues to present unique issues, this 200-year-old shield manifests a reflective luster as if polished by years of legal discourse that reveals the priorities of those who would interpret its text. Viewing the Fourth Amendment’s shield as a mirror illustrates not only the thoughts of the drafters that revolved primarily around protecting property interests but also the expectations of modern society with its insistence on promoting privacy. And where the drafters channeled their outrage against the loathsome writs of assistance in colonial times, later Americans continued to denounce the similarly invasive general warrants and attempts by investigators to expand the tools in their arsenal beyond constitutional bounds, especially in the surveillance context. Yet, the problems posed by new technology upon privacy concerns are best resolved by relying on the core principles supporting the Fourth Amendment, previous U.S. Supreme Court precedent, and current societal perspectives regarding privacy as a top priority proven by recently enacted legislation both foreign and domestic.

By applying a similar method to address advancing communication technology and its use as a surveillance tool in Carpenter v. United States, the Court turned this shield-become-mirror upon society to conclude that cell phone location information deserves Fourth Amendment protection because of its untiring comprehensiveness and its uniquely detailed nature. Moreover, nearly every American adult carries a cell phone with them almost all the time, making it possible to create a time-stamped map of any cell-phone-carrying-individual’s movements reaching back years and years. Unfortunately, the Carpenter Court did not extend this crucial protection far enough to protect all cell phone location data, and the unmistakable gap in its holding leaves a potential privacy vulnerability the exploitation of which could cause greater harm than all previously disputed surveillance technology combined because of cell phone usage’s general – near universal – applicability. Allowing cell phone location information to be obtained without probable cause and a proper search warrant not only fails to meet the spirit of the Fourth Amendment, it also begins to tarnish that shield such that it no longer reflects historical or current societal values, reducing its goal of protecting Americans to a hollow incantation of words left to languish as time (and technology) marches on.     

高可用性DHCP服务的设计与实现

分析了建立高可用性DHCP服务的迫切需求,根据DHCP服务体系结构,提出了DHCP服务的设计方法,并进行了周密的系统设计和系统部署,总结出了大型局域网部署DHCP服务的优化策略。     

Preparation and characterisation of an easily absorbabl Mg‐casein hydrolysate complex produced through enzymatic hydrolysis and ultrafiltration

In this study, we synthesised a Mg‐casein hydrolysate complex that allowed the effective absorption of Mg. The type of enzyme (papain, alcalase 2.4 L, pepsin, trypsin) and the enzyme/substrate ratio for casein hydrolysis was optimised. When the enzyme/substrate ratio was 30%, the alcalase 2.4 L‐hydrolysate showed the highest Mg‐chelation efficiency, of 96.1%. To characterise and enhance the function of casein hydrolysate, we fractionated the casein hydrolysate according to molecular weight using ultrafiltration. The Mg‐chelation efficiency was increased with the decrease in the molecular‐weight range of the hydrolysate fractions. The smallest casein hydrolysate (fraction 5, 1 kDa<) is used for preparation of Mg‐casein hydrolysate complex. Synthesised Mg‐casein hydrolysate complex (fraction 5) exhibited 100% Mg solubility and 39.5% Mg bioavailability. These results indicated that the Mg‐casein hydrolysate remained a stable chelate during simulated gastro‐intestinal digestion in vitro. The Mg‐casein hydrolysate complex exhibited excellent antioxidant activity as well as Mg binding.