In this pap er, we propose a class of AP selection algorithms based on the joining STA’s expected throughput by taking into account the above factors. Specifically, we collect a binary-valued local channel occupancy signal, called busy-idle (BI) signal, at each node and require the APs to perio dically broadcast their BI signal together with a quantity that represents TXOPs at the APs. This enables the joining STA to estimate expected throughput for each candidate AP before it selects one. To capture TXOPs at each AP, we propose a few different quantities, including the number of associated STAs, sum of inverse of MAC rates, and the average waiting and idle times.

关键词：无线局域网；802.11；接入点选择；多速率；TXOPs

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We address the problem of verifying Probabilistic Computation Tree Logic (PCTL) properties of Markov Decision Processes (MDPs) whose state transition probabilities are only known to lie within uncertainty sets.We first introduce the model of Convex-MDPs (CMDPs), i.e., MDPs with convex uncertainty sets. CMDPs generalize Interval-MDPs (IMDPs) by allowing also more expressive (convex) descriptions of uncertainty.Using results on strong duality for convex programs, we then present a PCTL verification algorithm for CMDPs, and prove that it runs in time polynomial in the size of a CMDP. This result allows us to lower the previously known algorithmic complexity upper bound for IMDPs from co-NP to PTIME, and it is valid also for more expressive (convex) uncertainty models.We validate the proposed approach on two case studies: the verification of a consensus protocol and of a dynamic configuration protocol for IPv4 addresses.

关键词：运行时验证；概率计算树逻辑；马尔可夫决策过程；PCTL；凸锥；多项式

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In this work it is shown that the thin mask boundary layers used to characterize these effects can be directly measured by capturing through-focus aerial images, a routine procedure for local quality inspection during mask fabrication. The Transport of Intensity phase imaging method is used to recover quantitative phase from a stack of intensity images, the phase near feature edges directly corresponding to edge effects at the mask. We discover that the Transport of Intensity solver produces errors in the solved phase near sharp corners due to strong curl effects in the power flow, and an iterative solver is developed to remedy the artifacts.

关键词：光掩模；边缘效应；相位成像；散焦

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This paper focused on the robustness of using software simulation models to predict the behavior of complex physical structures, such as the Super Ball tensegrity robot. Results included controlled locomotion simulations from a custom framework built on top of Bullet, a real-time physics simulation software, and initial rolling movement with a physical prototype. Software simulation models provided useful results for preliminary viability assessments, but should not replace physical prototyping, especially for complex structures. In conclusion, tensegrity robots could become promising alternatives to traditional rigid robots, which are more fragile and less flexible.

关键词：太空探索；张拉整体；机器人；软件仿真

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This paper proposes a SCADA system design that is based on a popular hybrid single-board computer. The controller is connected to a local wireless Ethernet/IP network with a secure IP-addressable radio and subsequently to the corporate intranet at the field central processing facility. The hybrid acts as a powerful and low-cost core for the controller. It is programmable in Python, and it is flexible, with provisions for digital outputs and most sensor inputs, as well as wireless sensor connections over Wi-Fi or Xbee radio standards. Sensor data are acquired and processed prior to being uploaded to a central database. To access the wellhead data, users log into a web-based graphical user interface (GUI). Similarly, the network structure allows users with proper permissions to send commands to, reprogram, and access the file system of individual controllers. Furthermore, the system applies an optimized control algorithm for sucker-rod pumps based on the Everitt-Jennings algorithm.

关键词：SCADA；数据采集；监控；CO2；EOR

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This paper describes our work building, evaluating and improving performance of a vision-based system running on an embedded computer onboard such a small UAS. This system utilises open source software and open hardware to automatically land a multi-rotor UAS with high accuracy. Using parallel computing techniques, our final implementation runs at the maximum possible rate of 30 frames per second. This demonstrates a valid approach for implementing other real-time vision based systems onboard UAS using low power, small and economical embedded computers.

关键词：嵌入式计算机；并行计算；实时图像处理；低成本

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In this thesis, we present the first formal model of CloudProxy, including a formal specification of desired security properties. We model CloudProxy as a transition system in the UCLID modeling language, using term-level abstraction. Our formal specification includes both safety and non-interference properties. We use induction to prove these properties, employing a back-end SMT-based verification engine. Further, we structure our proof as an "assurance case", showing how we decompose the proof into various lemmas, and listing all assumptions and axioms employed. We also perform some limited model validation to gain assurance that the formal model correctly captures behaviors of the implementation.

关键词：云代理；形式化建模；转换系统；验证

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We introduce "temporal lensing"---a technique that concentrates a relatively low-bandwidth flood into a short, high-bandwidth pulse. By leveraging existing DNS infrastructure, we experimentally explore lensing and the properties of the pulses it creates. We also show how attackers can use lensing to achieve peak bandwidths more than an order of magnitude greater than their upload bandwidth. While formidable by itself in a pulsing DoS attack, we note how lensing can be compatibly combined with amplification attacks to potentially allow attackers to produce pulses with peak bandwidths orders of magnitude larger than their own.

关键词：脉冲式；拒绝服务攻击；时间透镜；带宽

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Musical score following has many practical applications. As mobile devices get more popular, musicians would like to carry their sheet music on their mobile devices. One useful functionality that a sheet music app could offer is to have the app follow the music being played by the musician and turn pages at the right time. In this paper, we describe how we combined several techniques to accomplish this task and how we implemented it to run efficiently. By understanding basic sheet music semantics and how instruments produce sound, we carefully constructed a hidden Markov model to follow a player's position in a musical score solely by listening to their playing. We implemented our algorithm in Java, in the form of a sheet music application for Android, and it was able to successfully follow amateur-level pianists playing Twinkle Twinkle Little Star, as well as Minuet in G, by J.S. Bach.

关键词：音频源编码；乐谱；马尔科夫模型

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This thesis introduces {\it generalized arrows}, which are less restrictive than arrows in that they impose no containment relationship between the object language and metalanguage; this allows generalized arrows to be used for {\it heterogeneous} metaprogramming. This thesis also establishes a correspondence between two-level programs and one-level programs which take a generalized arrow instance as a distinguished parameter. A translation across this correspondence is possible, and is called a {\it flattening transformation}.

关键词：元编程；对象模型； GHC

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