Mark H. Overmars§ We present an algorithm for the hidden-surface elimination problem for rectangles, which is also known as window rendering. The time complexity of OUI algorithm is dependent on both the number of input rectangles, n, and on the size of the output, k. Our algorithm obtains a hade-off between these two components, in that its running time is O(r(nI+l/T" + k», where 1 5 r :S log ...

Let the edges of a graph G be coloured so that no colour is used more than k times. We refer to this as a k-bounded colouring. We say that a subset of the edges of G is multicoloured if each edge is of a different colour. We say that the colouring is H-good, if a multicoloured Hamilton cycle exists i.e., one with a multicoloured edge-set. Let ARk = {G : every k-bounded colouring of G is H-good}...

We give an improved approximation algorithm for the general kmedians problem. Given any > 0, the algorithm nds a solution of total distance at most D(1 + ) using at most k ln(n + n= ) medians (a.k.a. sites), provided some solution of total distance D using k medians exists. This improves over the best previous bound (w.r.t. the number of medians) by a factor of (1= ) provided 1= = n. The algori...

The growth-inhibitory effect of cyclocreatine (CCr) and the kinetics of CCr and Na+ cotransport were investigated in MCF7 human breast cancer cells and its adriamycin-resistant subline with use of 31P- and23Na-NMR spectroscopy. The growth-inhibitory effect in the resistant line occurred at a lower CCr concentration and was more pronounced than in the wild-type line. This correlated with an ∼10-...

Wilson’s [19] model of oracle gates provides a framework for considering reductions whose strength is intermediate between truth-table and Turing. Improving on a stream of results by Beigel, Reingold, Spielman, Fortnow, and Ogihara [6, 9, 14], we prove that PL and PP are closed under NC1 reductions. This answers an open problem of Ogihara [14]. More generally, we show that NC k+1 = AC k and NC ...

As clock frequency increases and feature size decreases, clock distribution and wire delays present a growing challenge to the designers of singly-clocked, globally synchronous systems. We describe an alternative approach, which we call a Multiple Clock Domain (MCD) processor, in which the chip is divided into several (coarse-grained) clock domains, within which independent voltage and frequenc...

Aim of this study was to evaluate, in Renal Transplant Recipients (RTR), a new method to predict Creatinine Clearance (Ccr) from Plasma Creatinine (Pcr) and from the value of Body Cell Mass (BCM). The values of BCM were obtained, from body impedance analysis (BIA) using an impedance plethysmograph, in 87 RTR with different graft function. The ratios of 24-hour Urinary Creatinine Excretion (Ucr)...

*Preliminary versions of the various results in this paper appeared in Proc. of the 30th IEEE Annual Symp. on Foundation of Computer Science, 1989, and Proc. of the Ele ̈enth w x Annual ACM Symp. on Principles of Distributed Computing, 1992 AMS89, AGR92 . Supported by Air Force Contract TNDGAFOSR-86-0078, ARO Contract DAAL03-86-K0171, NSF Contract CCR8611442, and a special grant from IBM. Suppor...