Android provides tools to enable rich interaction, but if developers do not know how to use them correctly, they will not use them securely. In this dissertation, we examine how mobile applications interact with each other and their environment. We uncover threats to application security due to developer confusion and general misuse of the features provided by the mobile platform. Specifically, we perform an in-depth analysis of how Android applications interact with each other through inter-process communication mechanisms, how they interact with system resources through Android permissions, and how they interact with web content through WebViews. We build static analysis tools to identify vulnerable applications and measure the prevalence of the vulnerabilities. Through automated and manual analysis, we identify patterns that illustrate how developers misuse these features and make their application vulnerable to attack. We further provide platform-level, API-level, and design-leve solutions to help developers and platform designers build secure applications and systems.

关键词：移动应用；安全性；应用程序；安卓

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In this work, we derive a new parallel communication-avoiding matrix powers algorithm for matrices of the form A = D+USV H, where D is sparse and USV H has low rank but may be dense. Matrices of this form arise in many practical applications, including power-law graph analysis, circuit simulation, and algorithms involving hierarchical (H) matrices, such as multigrid methods, fast multipole methods, numerical partial di erential equation solvers, and preconditioned iterative methods.

关键词：移动数据；并行通讯；并行矩阵

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Increasing demand for information processing in the last 50 years has been largely satis ed by the steadily declining price and improving performance of microelectronic devices. Much of this progress has been made by aggressively scaling the size of semiconductor transistors and metal interconnects that microprocessors are built from. As devices shrink to the size regime in which quantum e ects pose signicant challenges, new physics may be required in order to continue historical scaling trends. A variety of new devices and physics are currently under investigation throughout the scienti c and engineering community to meet these challenges.

关键词：微电子设备；纳米；磁设备；信息处理；半导体晶体管

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Fully printable flexible transistors are key to high throughput production of flexible electronics at low cost. In this work, the advantages of an inverse gravure printing system and the solution-processing of 99% semiconductor enriched single-walled carbon nanotube (SWCNT) solutions are combined to fabricate fully printable SWCNT flexible top-gated thin-film transistors. The fully printed transistors exhibit high performance with mobility and on/off ratio up to 7.8 cm2/Vs and 104 while remaining stable when bent to 1 mm radius of curvature. With the transistors’ high performance, throughput, uniformity, flexibility and stability, we have demonstrated the potential for our printing process scheme to serve as the backplane for future scalable, low cost, high throughput, flexible electronics applications.

关键词：电子产业；碳纳米管；半导体；晶体管；电子应用程序

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Central to many statistical inference problems is the computation of some quantities defined over variables that can be fruitfully modeled in terms of graphs. Examples of such quantities include marginal distributions over graphical models and empirical average of observations over sensor networks. For practical purposes, distributed message-passing algorithms are well suited to deal with such problems. In particular, the computation is broken down into pieces and distributed among different nodes. Following some local computations, the intermediate results are shared among neighboring nodes via the so called messages. The process is repeated until the desired quantity is obtained. These distributed inference algorithms have two primary aspects: statistical properties, in which characterize how mathematically sound an algorithm is, and computational complexity that describes the efficiency of a particular algorithm. In this thesis, we propose low-complexity (efficient), message-passing algorithms as alternatives to some well known inference problems while providing rigorous mathematical analysis of their performances. These problems include the computation of the marginal distribution via belief propagation for discrete as well as continuous random variables, and the computation of the average of distributed observations in a noisy sensor network via gossip-type algorithms.

关键词：低复杂度；算法；分布式计算；消息传递

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This thesis introduces CANDID, a passive NetFlow-based network traffic analysis platform targeted at inferring relationships and dependencies among services running on hosts in enterprise networks. These networks present challenges of great scale, complexity, and nonstop dynamism, which hinder the ability for network administrators to maintain insight into the complex relationships that exist in these networks. Consequently, administrators do not always know how best to proceed if a network failure occurs. CANDID strives to empower administrators by illuminating these relationships, such that they will be prepared to remedy complex service failures.The solutions presented here take the rst steps towards understanding these complex in-network relationships, with a special focus on inferring one class of dependencies and detecting load balanced services. The focal point of this thesis is two radically di erent, yet complementary, strategies for inferring the presence of load balancing for pairs of systems.

关键词：网络故障；复杂网络关系；依赖性；重要性

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Modern websites perform many cross-site requests that can be detrimental to user privacy. Cross-site requests undermine privacy by allowing third-party websites——the websites that are the recipients of cross-site requests——to track a user's browsing behavior. As a result, some users turn to browser extensions that give them control over these requests. One such extension, RequestPolicy, implements a default-deny policy for cross-site requests and provides users an interface through which they manage a whitelist to allow blocked requests. This approach breaks many websites and requires frequent user interaction. We set out to gain insight into how RequestPolicy is used. We study RequestPolicy's usage through an opt-in telemetry study. Over a period of 24 weeks, we collected data from more than 2,500 RequestPolicy users about how they interact with RequestPolicy. We use this data, user feedback, and our own experiences to guide a redesign of RequestPolicy.

关键词：需求政策；交互；网站；用户隐私；跨站点请求

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Communication, i.e., moving data, between levels of a memory hierarchy or between parallel processors on a network, can greatly dominate the cost of computation, so algorithms that minimize communication can run much faster (and use less energy) than algorithms that do not. Motivated by this, attainable communication lower bounds were established in [12, 13, 4] for a variety of algorithms including matrix computations.The resultapplies to recursive programs, irregular iteration spaces, sparse matrices, and other data structures as long asthe computation can be logically mapped to loops and indexed data structure accesses. We also discuss whenoptimal algorithms exist that attain the lower bounds; this leads to new asymptotically faster algorithms forseveral problems.

关键词：通讯；最优算法；程序；最小通信；矩阵乘法

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Maximum constraint satisfaction problem (Max-CSP) is a rich class of combinatorial optimization problems. In this dissertation, we show optimal (up to a constant factor) NPhardness for maximum constraint satisfaction problem with k variables per constraint (Max- k-CSP), whenever k is larger than the domain size. This follows from our main result concerningCSPs given by a predicate: a CSP is approximation resistant if its predicate containsa subgroup that is balanced pairwise independent. Our main result is related to previous works conditioned on the Unique-Games Conjecture and integrality gaps in sum-of squares semide nite programming hierarchies.

关键词：最大约束满意度问题；组合最优问题；编程

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This document introduces the syntax of BLOG, a probabilistic programming language, for describing random variables and their probabilistic dependencies. BLOG defines probabilistic generative models over first-order structures. For example, all Bayesian networks can be easily described by BLOG. BLOG has the following features: (a) it employs open-universe semantics; (b) it can describe relational uncertainty; (c) it can handle identity uncertainty; and (d) it is empowered by first-order logic. The syntax as described in this document corresponds to BLOG version 0.6. The current version represents a significant redesign and extension to previous versions of BLOG, based on the principles of usability and implementation efficiency.

关键词：博客；语言；语法

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