Clustering with diversity

We consider the {\em clustering with diversity} problem: given a set of colored points in a metric space, partition them into clusters such that each cluster has at least $\ell$ points, all of which have distinct colors. We give a 2-approximation to this problem for any $\ell$ when the objective is to minimize the maximum radius of any cluster. We show that the approximation ratio is optimal unless $\mathbf{P=NP}$, by providing a matching lower bound. Several extensions to our algorithm have also been developed for handling outliers. This problem is mainly motivated by applications in privacy-preserving data publication.Comment: Extended abstract accepted in ICALP 2010. Keywords: Approximation algorithm, k-center, k-anonymity, l-diversit

Randomized Algorithms for Tracking Distributed Count, Frequencies, and Ranks

We show that randomization can lead to significant improvements for a few fundamental problems in distributed tracking. Our basis is the {\em count-tracking} problem, where there are $k$ players, each holding a counter $n_i$ that gets incremented over time, and the goal is to track an \eps-approximation of their sum $n=\sum_i n_i$ continuously at all times, using minimum communication. While the deterministic communication complexity of the problem is \Theta(k/\eps \cdot \log N), where $N$ is the final value of $n$ when the tracking finishes, we show that with randomization, the communication cost can be reduced to \Theta(\sqrt{k}/\eps \cdot \log N). Our algorithm is simple and uses only O(1) space at each player, while the lower bound holds even assuming each player has infinite computing power. Then, we extend our techniques to two related distributed tracking problems: {\em frequency-tracking} and {\em rank-tracking}, and obtain similar improvements over previous deterministic algorithms. Both problems are of central importance in large data monitoring and analysis, and have been extensively studied in the literature.Comment: 19 pages, 1 figur

Optimal Tracking of Distributed Heavy Hitters and Quantiles

We consider the the problem of tracking heavy hitters and quantiles in the distributed streaming model. The heavy hitters and quantiles are two important statistics for characterizing a data distribution. Let $A$ be a multiset of elements, drawn from the universe $U=\{1,...,u\}$. For a given $0 \le \phi \le 1$, the $\phi$-heavy hitters are those elements of $A$ whose frequency in $A$ is at least $\phi |A|$; the $\phi$-quantile of $A$ is an element $x$ of $U$ such that at most $\phi|A|$ elements of $A$ are smaller than $A$ and at most $(1-\phi)|A|$ elements of $A$ are greater than $x$. Suppose the elements of $A$ are received at $k$ remote {\em sites} over time, and each of the sites has a two-way communication channel to a designated {\em coordinator}, whose goal is to track the set of $\phi$-heavy hitters and the $\phi$-quantile of $A$ approximately at all times with minimum communication. We give tracking algorithms with worst-case communication cost O(k/\eps \cdot \log n) for both problems, where $n$ is the total number of items in $A$, and \eps is the approximation error. This substantially improves upon the previous known algorithms. We also give matching lower bounds on the communication costs for both problems, showing that our algorithms are optimal. We also consider a more general version of the problem where we simultaneously track the $\phi$-quantiles for all $0 \le \phi \le 1$.Comment: 10 pages, 1 figur

微粒的功能及其与糖尿病的研究进展

MPs are vesicles released by cells when stimulated by physical (e.g. shear force) or chemical (e.g. agonists) factors, as well as cells undergoing apoptosis or exposed to inflammatory conditions . MPs are 100~1000 nm in diameter, have membrane cytoskeletons, express phosphatidylserine (PS) on the surface, and lack of nuclei. Surface molecules, enzymes, RNA and DNA are conveyed via MPs from origin cells to target cells. As mediators of information transfer, MPs have been proposed to impose pro-inflammatory and pro-coagulant effects in many disease states, such as cancer, venous thromboembolism, arteriosclerosis, and diabetes mellitus. The hypercoagulable state associated with diabetes is well recognized. More T2DM patients have died from thrombotic diseases. The endothelium-derived MPs in diabetic patients were elevated. TF-positive MPs concentration was increased and procoagulant activity of MPs was elevated. It is worth to research the role of MPs in the hypercoagulable state of diabetic patients.微粒是由细胞受物理或化学刺激或者凋亡时产生的带细胞膜的囊泡。其大小在100~1000nm之间，表面的膜细胞骨架上含有磷脂酰丝氨酸及多种细胞分子，其包膜内无核，含有细胞分子、RNA、DNA等。在机体中起到信号传递的作用。近年来发现，微粒参与多种疾病的病理生理过程，如糖尿病、冠心病、深静脉血栓、肿瘤等，在以上疾病过程中，微粒主要有促炎、促凝等作用。糖尿病患者存在明显的高凝状态，糖尿病患者合并心血管疾病死亡率近年来有增高趋势，血栓事件较非糖尿病患者增加。糖尿病患者血浆中内皮源性微粒数目增多，组织因子阳性微粒比例升高，微粒促凝活性升高。微粒的改变是否参与糖尿病患者的高凝状态的发生值得研究

Macrophage migration inhibitory factor (MIF) family in arthropods : Cloning and expression analysis of two MIF and one D-dopachrome tautomerase (DDT) homologues in Mud crabs, Scylla paramamosain

Acknowledgements This research was supported by grants from the National Natural Science Foundation of China (Nos. 31172438 and U1205123), the Natural Science Foundation of Fujian Province (No. 2012J06008 and 201311180002) and the projects-sponsored by SRF. TW received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Peer reviewedPostprin