This paper presents a voltage-controlled oscillator (VCO)-based readout ADC for quasi-static sensor applications. The proposed VCO-based ADC is implemented in a low-temperature polycrystalline silicon thin-film transistor (LTPS-TFT) process. To mitigate the severe offset and flicker noise in the TFT technology, this design adopts a relaxation-based VCO and a system-level chopping scheme. To improve the linearity and widen the input range, a foreground 3rd-order polynomial-fitted compensation is adopted in this design. This readout ADC is fabricated in a 3-µm LTPS-TFT process and occupies a core area of only 3.6 mm2. With a 5-V supply voltage, the proposed VCO-ADC achieves a 48.2-dB SNR with a 0.6-V input at a bandwidth of 250 Hz. The total power consumption is 505 µW. The ADC’s dynamic range is 59.5 dB. The corresponding Walden’s figure of merit (FoMw) is 4.8 nJ/conversion-step.

One of the most important issues in offering real-time communication services in a mobile environment is support for seamless handover between base stations during a communication session. In Mobile WiMAX, a mobile station may have to perform a scan and association process before handover, but unfortunately, this scan and association process introduces service disruption. In this letter, we investigate the scan and association latency in Mobile WiMAX, and evaluate its performance through analytic models and simulations.

There are two principal methods for turning regular expressions into NFA's — one due to McNaughton and Yamada and another due to Thompson. Unfortunately, both have drawbacks. Given a regular expression R of length r and with s occurrences of alphabet symbols, Chang and Paige (1992) and Brüggemann-Klein (1993) gave Θ(m + r) time and O(r) space algorithms to produce a Θ(m) space representation of McNaughton and Yamada's NFA with s + 1 states and m transitions. The problem with this NFA is that m = Θ(s2) in the worst case. Thompson's method takes Θ(r) time and space to construct a Θ(r) space NFA with Θ(r) states and Θ(r) transitions. The problem with this NFA is that r can be arbitrarily larger than s. We overcome drawbacks of both methods with a Θ(r) time Θ(s) space algorithm to construct an O(s) space representation of McNaughton and Yamada's NFA. Given any set V of NFA states, our representation can be used to compute the set U of states one transition away from the states in V in optimal time O(¦V¦ + ¦U¦). McNaughton and Yamada's NFA requires Θ(¦V¦ × ¦U¦) time in the worst case. Using Thompson's NFA, the equivalent calculation requires Θ(r) time in the worst case. Comparative benchmarks show that an implementation of our method outperforms implementations of competing methods with respect to time for NFA construction, NFA accepting testing, and NFA-to-DFA conversion by subset construction. Throughout this paper program transformations are used to design algorithms and derive programs. A transformation of special importance is a form of finite differencing used previously by Douglas Smith to improve the efficiency of functional programs.

The problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclidean space is considered. The diameter of a spanning tree is the maximum distance between any two points in the tree. A characterization of an MDST is given and a $\theta (n^3)$-time algorithm for solving the problem is presented. The authors also show that for a weighted undirected graph, the problem of determining if a spanning tree with total weight and diameter upper bounded, respectively, by two given parameters C and D exists is NP-complete. The geometric Steiner minimum diameter spanning tree problem, in which new points are allowed to be part of the spanning tree, is shown to be solvable in $O(n)$ time.

We consider the problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclidean plane. The diameter of a spanning tree is the maximum distance between any two points in the tree. We give a characterization of an MDST and present a θ(n3 time algorithm for solving the problem. We also show that for a weighted undirected graph, the problem of determining if a spanning tree with total weight and diameter upper bounded, respectively, by two given parameters C and D exists is N P-complete. The geometrical minimum diameter Steiner tree problem, in which new points are allowed to be part of the spanning tree, is shown to be solvable in Ο(n) time.