Searching for a goal is a central and extensively studied problem in computer science. In classical searching problems, the cost of a search function is simply the number of queries made to an oracle that knows the position of the goal. In many robotics problems, as well as in problems from other areas, we want to charge a cost proportional to the distance between queries (e.g., the time required to travel between two query points). With this cost function in mind, the abstract problem known as the w-lane cow-path problem was designed. There are known optimal deterministic algorithms for the cow-path problem; we give the first randomized algorithm in this paper. We show that our algorithm is optimal for two paths (w = 2) and give evidence that it is optimal for larger values of w. Subsequent to the preliminary version of this paper, Kao et al. (in "Proceedings, 5th ACM-SIAM Symposium on Discrete Algorithm," pp. 372-381, 1994) have shown that our algorithm is indeed optimal for all w ≥ 2. Our randomized algorithm gives expected performance that is almost twice as good as is possible with a deterministic algorithm. For the performance of our algorithm, we also derive the asymptotic growth with respect to w-despite similar complexity results for related problems, it appears that this growth has never been analyzed.

We studied the effect of telemonitoring in addition to usual care compared to usual care alone in patients with chronic obstructive pulmonary disease (COPD). A total of 110 patients with moderate to severe COPD were recruited from a specialist respiratory service in Northern Ireland. Patients had at least two of: emergency department admissions, hospital admissions or emergency general practitioner (GP) contacts in the 12 months before the study. Exclusion criteria were patients who had any respiratory disorder other than COPD, or were cognitively unable to learn the process of monitoring. Patients were randomised to receive six months of home telemonitoring with usual care, or six months of usual care. The primary outcome measure was disease-specific quality of life, as measured by the St George's Respiratory Questionnaire for COPD patients (SGRQ-C). Of 100 patients completing the study, 48 patients were randomised to telemonitoring and 52 patients were randomised to the control group. The SGRQ-C scores improved significantly in the intervention group compared to usual care (P = 0.001). The HADS anxiety score was significantly higher in the telehealth group compared to the usual care group (P = 0.01). There were significantly more contacts with the Community Respiratory Team in the telemonitoring group compared to the control group (P = 0.029). There were no significant between group differences in EQ-5D scores, HADS depression scores, GP activity, emergency department visits, hospital admissions or exacerbations. The total cost to the health service of the intervention over the 6-month study period was £2039, giving an estimated ICER of £203,900. In selected patients with COPD, telemonitoring was effective in improving health-related quality of life and anxiety, but was not a cost-effective intervention.

(c) 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. Abstract:In this paper, we consider a model of lossless image compression in which each band of a multispectral image is coded using a prediction function involving values from a previously coded band of the compression, and examine how the ordering of the bands affects the achievable compression.We present an efficient algorithm for computing the optimal band ordering for a multispectral image. This algorithm has time complexity O(n 2 ) for an n-band image, while the naive algorithm takes time (n!). A slight variant of the optimal ordering problem that is motivated by some practical concerns is shown to be NP-hard, and hence, computationally infeasible, in all cases except for the most trivial possibility.In addition, we report on our experimental findings using the algorithms designed in this paper applied to real multispectral satellite data. The results show that the techniques described here hold great promise for application to real-world compression needs.Index Terms-Compression, lossless compression, image compression, multispectral images, satellite data, NPcompleteness. Article:1 INTRODUCTION MULTISPECTRAL satellite images require enormous amounts of space, and with NASA's project EOS (the Earth Observing System), data will be generated at an unprecedented rate. The estimates are that over a terabyte (10 12 bytes) of data will be generated every day by the EOS satellites, most of it multispectral image data. Largely due to this fact, a lot of attention has recently been focused on compression of multispectral images [5]. However, most of the compression methods that exploit spectral as well as spatial redundancy have been lossy compression algorithms, and for archival storage and for certain applications it is important to use lossless compression in order to preserve all of the data that is collected. One notable exception to this is the work of Roger and Cavenor [4] who extensively study various prediction and coding methods used for lossless compression of AVIRIS data. Table 1 lists some current, widely used multispectral sources, with their acronyms, full names, and basic properties-it is data from these sensors that we used in this study.In this paper, we study lossless compression of multispectral images. Spectral redundancy is extracted by coding each band of the multispectral image by making use of a second -prediction band.‖ In much the same way that standard single-image lossless compression is separated into the two separate components of prediction and coding, we divide the lossless compression of multispectral images into three components: band ordering, prediction, and coding. The new stage, band ordering, refers to selecting a permutation...

Abstract. A Threshold Circuit consists of an acyclic digraph of unbounded fanin, where each node computes a threshold function or its negation. This paper investigates the computational power of Threshold Circuits. A surprising relationship is uncovered between Threshold Circuits and another class of unbounded fanin circuits which are denoted Finite Field Z P n Circuits, where each node computes either multiple sums or products of integers modulo a prime P n. In particular, it is proved that all functions computed by Threshold Circuits of size Sn n and depth Dn can also be computed by Z P n Circuits of size OS nlog Sn + nP n log P n and depth ODn. Furthermore, it is shown that all functions computed by Z P n Circuits of size S n and depth Dn can be computed by Threshold Circuits of size O 1 2 Sn log P n 1+ and depth O 1 5 Dn.These are the main results of this paper.There are many useful and quite surprising consequences of this result. For example, integer reciprocal can be computed in size n O1 and depth O1. More generally, a n y analytic function with a convergent rational polynomial power series such as sine, cosine, exponentiation, square root, and logarithm can be computed within accuracy 2 ,n c , for any constant c, b y Threshold Circuits of polynomial size and constant depth. In addition, integer and polynomial division, FFT, polynomial interpolation, Chinese Remaindering, all the elementarysymmetric functions, banded matrix inverse, and triangular Toeplitz matrix inverse can be exactly computed by Threshold Circuits of polynomial size and constant depth. All these results and simulations hold for polytime uniform circuits. This paper also gives a corresponding simulation of logspace uniform Z P n Circuits by logspace uniform Threshold Circuits requiring an additional multiplying factor of Olog log log P n depth.Finally, purely algebraic methods for lower bounds for Z P n Circuits are developed. Using degree arguments, a Depth Hierarchy Theorem for Z P n Circuits is proved: for any S n n, Dn = O S n c 0 for some constant c 0 1, and prime P n where 6Sn=Dn Dn P n 2 n , there exists explicitly constructible functions computable by Z P n Circuits of size Sn and depth Dn, but provably not computable by Z P n Circuits of size Sn c and depth oDn for any constant c 1:

Abstract. Direct anonymous attestation (DAA) is an anonymous authentication scheme adopted by the Trusted Computing Group in its specifications for trusted computing platforms. This paper presents an efficient construction that implements all anonymous authentication features specified in DAA, including authentication with total anonymity, authentication with variable anonymity, and rogue TPM tagging. The current DAA construction is mainly targeted for powerful devices such as personal computers, and their corresponding application areas, but is not entirely suitable for embedded devices with limited computing capabilities (e.g., cell phones or hand-held PDAs). We propose a new construction with more efficient sign and verify protocols, making it more attractive for embedded devices. We prove that the new construction is secure under the strong RSA assumption and the decisional DiffieHellman assumption.