Guest Editors' Introduction: Security & Privacy

Security and privacy concerns touch on all aspects of pervasive computing, including hardware, operating systems, networks, databases, user interfaces, and applications. The seven articles selected for this special issue draw on ideas from many of these fields and provide a flavor of the kinds of security and privacy challenges and opportunities in pervasive computing. This article is part of a special issue on security and privacy.     

Developing a distributed system for infrastructure protection

Your business increasingly relies on computer-controlled systems vulnerable to intrusion and destruction. The recent distributed denial of service attacks against e-commerce companies showed that this vulnerability extends beyond your own corporate networks: the very infrastructure of the Internet is at risk. When infoterrorists use the networks' high connectivity and low security to launch attacks against critical information infrastructure systems, they can not only disrupt global e-commerce and communications, but can also adversely affect other critical infrastructure services such as energy, transportation, health care, finance, and water supply. How can organizations protect these systems from infoterrorism? They must leverage modern information technologies to create an infrastructure protection process that can operate quickly and seamlessly. We propose a six-stage protection process that involves intelligence gathering, analysis, interdiction, detection, response, and recovery. To implement this process, we've designed an underlying Web-like architecture that will serve as a platform for the decentralized monitoring and management of critical infrastructures     

Why Johnny Can't Evaluate Security Risk

S&P editor in chief George Cybenko proposes solutions to make evaluating security and privacy risks an easier task.     

The Traveling Agent Problem

 This paper considers a sequencing problem which arises naturally in the scheduling of software agents. We are given n sites at which a certain task might be successfully performed. The probability of success is p _i at the ith site and these probabilities are independent. Visiting site i and trying the task there requires time (or some other cost metric) t _i whether successful or not. Latencies between sites i and j are l _ij, that is, the travel time between those two sites. Should the task be successfully completed at a site then any remaining sites do not need to be visited. The Traveling Agent Problem is to find the sequence which minimizes the expected time to complete the task. The general formulation of this problem is NP-Complete. However, if the latencies are constant we show that the problem can be solved in polynomial time by sorting the ratios t _i/p _i according to increasing value and visiting the sites in that order. This result then leads to an efficient algorithm when groups of sites form subnets in which latencies within a subnet are constant but can vary across subnets. We also study the case when there are deadlines for solving the problem in which case the goal is to maximize probability of success subject to satisfying the deadlines. Applications to mobile and intelligent agents are described. Date received: February 10, 1998. Date revised: November 16, 1999.     

Keeping up with the changing Web

Most information depreciates over time, so keeping Web pages current presents new design challenges. This article quantifies what “current” means for Web search engines and estimates how often they must reindex the Web to keep current with its changing pages and structure     

Functional Validation in Grid Computing

The development of the World Wide Web has changed the way we think about information. Information on the web is distributed, updates are made asynchronously and resources come online and go offline without centralized control. Global networking will similarly change the way we think about and perform computation. Grid computing refers to computing in a distributed networked environment where computing and data resources are located throughout a network. In order to locate these resources dynamically in a grid computation, a broker or matchmaker uses keywords and ontologies to describe and specify grid services. However, we believe that keywords and ontologies can not always be defined or interpreted precisely enough to achieve deep semantic agreement in a truly distributed, heterogeneous computing environment. To this end, we introduce the concept of functional validation. Functional validation goes beyond the symbolic level of brokering and matchmaking, to the level of validating actual functional performance of grid services. In this paper, we present the functional validation concept in grid computing, analyze the possible validation situations and apply basic machine learning theory such as PAC learning and Chernoff bounds to explore the relationship between sample size and confidence in service semantics.     

基于状态软集结的相对值迭代算法

在大规模随机控制问题中,值函数逼近是一种克服维数灾的方法,考虑平均模型马氏决策规划（ＭＤＰ）的状态软集结相对值迭代算法,在Ｓｐａｎ压缩的条件下,证明了该算法的收敛性,同时还给出了其误差估计。     

Cybersecurity Strategies: The QuERIES Methodology

QuERIES offers a novel multidisciplinary approach to quantifying risk associated with security technologies resulting in investment-efficient cybersecurity strategies.     

Homeland security

Trends & Controversies this issue grows out of a panel discussion at the 2005 AAAI Spring Symposium on Al Technologies and Homeland Security, held at Stanford University in March 2005. Robert Popp, who gave the keynote speech at the symposium, describes a DARPA initiative for dealing with the 21st-century strategic threat triad: failed states, global terrorism, and weapons of mass destruction proliferation. George Cybenko presents a philosophical/strategic viewpoint on national security. K.A. Taipale discusses policy implications of using trusted systems for counterterrorism security and how risk management, decision heuristics, and the presumption of innocence relate to such systems. Latanya Sweeney proposes privacy-aware technology (selective revelation) that allows data about people to be shared for surveillance purposes while protecting their privacy. Paul Rosenzweig points out two major changes in privacy protection in the post-9/11 era: the broadening of the approach to generating privacy policy/rules from a purely top-down process to one that includes a bottom-up component in which privacy is protected through institutional oversight, and a change from a focus on rules to a focus on results. These five articles present a snapshot of the complex interactions between information security and privacy. A comprehensive understanding of such interactions is critical for developing solutions, whether they are technological solutions, political solutions, or both.