Integrated optical devices based on broadband epsilon-near-zero meta-atoms

We verify the feasibility of the proposed theoretical strategy for designing the broadband near-zero permittivity (ENZ) metamaterial at optical frequency range with numerical simulations. In addition, the designed broadband ENZ stack are used as meta-atoms to build functional nanophotonic devices with extraordinary properties, including an ultranarrow electromagnetic energy tunneling channel and an ENZ concave focusing lens.Comment: 3 pages, 3 figure

A Decomposition Theorem for Maximum Weight Bipartite Matchings

Let G be a bipartite graph with positive integer weights on the edges and without isolated nodes. Let n, N and W be the node count, the largest edge weight and the total weight of G. Let k(x,y) be log(x)/log(x^2/y). We present a new decomposition theorem for maximum weight bipartite matchings and use it to design an O(sqrt(n)W/k(n,W/N))-time algorithm for computing a maximum weight matching of G. This algorithm bridges a long-standing gap between the best known time complexity of computing a maximum weight matching and that of computing a maximum cardinality matching. Given G and a maximum weight matching of G, we can further compute the weight of a maximum weight matching of G-{u} for all nodes u in O(W) time.Comment: The journal version will appear in SIAM Journal on Computing. The conference version appeared in ESA 199

An Even Faster and More Unifying Algorithm for Comparing Trees via Unbalanced Bipartite Matchings

A widely used method for determining the similarity of two labeled trees is to compute a maximum agreement subtree of the two trees. Previous work on this similarity measure is only concerned with the comparison of labeled trees of two special kinds, namely, uniformly labeled trees (i.e., trees with all their nodes labeled by the same symbol) and evolutionary trees (i.e., leaf-labeled trees with distinct symbols for distinct leaves). This paper presents an algorithm for comparing trees that are labeled in an arbitrary manner. In addition to this generality, this algorithm is faster than the previous algorithms. Another contribution of this paper is on maximum weight bipartite matchings. We show how to speed up the best known matching algorithms when the input graphs are node-unbalanced or weight-unbalanced. Based on these enhancements, we obtain an efficient algorithm for a new matching problem called the hierarchical bipartite matching problem, which is at the core of our maximum agreement subtree algorithm.Comment: To appear in Journal of Algorithm

Cavity Matchings, Label Compressions, and Unrooted Evolutionary Trees

We present an algorithm for computing a maximum agreement subtree of two unrooted evolutionary trees. It takes O(n^{1.5} log n) time for trees with unbounded degrees, matching the best known time complexity for the rooted case. Our algorithm allows the input trees to be mixed trees, i.e., trees that may contain directed and undirected edges at the same time. Our algorithm adopts a recursive strategy exploiting a technique called label compression. The backbone of this technique is an algorithm that computes the maximum weight matchings over many subgraphs of a bipartite graph as fast as it takes to compute a single matching

COMPARISON OF THREE EXERCISE THERAPIES FOR RECREATIONAL RUNNERS WITH CHRONIC LOW BACK PAIN

The prevalence of low back pain (LBP) in among recreational runners is high. A singleblinded (outcome assessor blinded) randomized trial was conducted to evaluate the effectiveness of a novel therapy using lower limb (LL) exercises, in comparison with 2 conventional therapies [(lumbar extensor (LE) exercises and lumbar stabilization (LS) exercises], in managing chronic LBP in recreational runners. Eighty-four runners, assigned to 1 of the 3 exercise groups, completed 8 weeks of exercise therapy. The findings revealed that LL exercise therapy was superior to the 2 conventional exercise therapies in improving running functional outcome and knee extension strength, and was equally effective in improving lumbar multifidus activation. Thus, the novel LL exercise therapy is recommended for clinical management of chronic LBP in recreational runners

Power Quality Investigation with Wavelet Techniques

Electric power quality is an aspect of power engineering that has been with us since the inception of power systems. However, the topics in power quality have only attracted interests over the past few years because of the increasing usage of electronically controlled equipments. The power quality problem causes interruptions to the sensitive electrical or electronic equipment and results in very expensive consequences. Wavelet techniques will be studied in this paper for analysing monitored power quality data. A case study based on the measurement of a University of Queensland site was studied using the proposed wavelet approach

SHOT PERFORMANCE AND CUE STICK KINEMATICS OF TOP SPIN SHOTS IN CUE SPORTS PLAYERS OF VARIOUS PLAYING LEVELS

This study aimed to compare the shot performance and kinematics of the cue stick in top spin shots between less-skilled and skilled players. Twenty-five cue sports players were recruited and assigned to the less-skilled (n = 12) or skilled (n = 13) groups. Ten successful top spin trials were recorded for each participant. 2D video analysis was employed to evaluate shot performance which was represented by an error distance. A 3D motion capture system was used to obtain kinematic data of the cue stick during the cueing movement. The results showed that skilled players were more consistent in their performance with lower inter-trial variability than less-skilled players (p = 0.028). No significant differences between two groups were found in the cue stick kinematics including height (p = 0.723), speed (p = 0.153), and angle (p = 0.380). The results indicated that similar cueing techniques were adopted by all participants. Further analysis of human body kinematics is in need to uncover potential technique differences among players despite achieving similar cueing movements