Computing the Ball Size of Frequency Permutations under Chebyshev Distance

Let $S_n^\lambda$ be the set of all permutations over the multiset $\{\overbrace{1,...,1}^{\lambda},...,\overbrace{m,...,m}^\lambda\}$ where $n=m\lambda$. A frequency permutation array (FPA) of minimum distance $d$ is a subset of $S_n^\lambda$ in which every two elements have distance at least $d$. FPAs have many applications related to error correcting codes. In coding theory, the Gilbert-Varshamov bound and the sphere-packing bound are derived from the size of balls of certain radii. We propose two efficient algorithms that compute the ball size of frequency permutations under Chebyshev distance. Both methods extend previous known results. The first one runs in $O({2d\lambda \choose d\lambda}^{2.376}\log n)$ time and $O({2d\lambda \choose d\lambda}^{2})$ space. The second one runs in $O({2d\lambda \choose d\lambda}{d\lambda+\lambda\choose \lambda}\frac{n}{\lambda})$ time and $O({2d\lambda \choose d\lambda})$ space. For small constants $\lambda$ and $d$, both are efficient in time and use constant storage space.Comment: Submitted to ISIT 201

A Dichotomy Result for Cyclic-Order Traversing Games

Traversing game is a two-person game played on a connected undirected simple graph with a source node and a destination node. A pebble is placed on the source node initially and then moves autonomously according to some rules. Alice is the player who wants to set up rules for each node to determine where to forward the pebble while the pebble reaches the node, so that the pebble can reach the destination node. Bob is the second player who tries to deter Alice\u27s effort by removing edges. Given access to Alice\u27s rules, Bob can remove as many edges as he likes, while retaining the source and destination nodes connected. Under the guide of Alice\u27s rules, if the pebble arrives at the destination node, then we say Alice wins the traversing game; otherwise the pebble enters an endless loop without passing through the destination node, then Bob wins. We assume that Alice and Bob both play optimally. We study the problem: When will Alice have a winning strategy? This actually models a routing recovery problem in Software Defined Networking in which some links may be broken. In this paper, we prove a dichotomy result for certain traversing games, called cyclic-order traversing games. We also give a linear-time algorithm to find the corresponding winning strategy, if one exists

Dependent k-Set Packing on Polynomoids

Specialized hereditary systems, e.g., matroids, are known to have many applications in algorithm design. We define a new notion called d-polynomoid as a hereditary system (E, ? ? 2^E) so that every two maximal sets in ? have less than d elements in common. We study the problem that, given a d-polynomoid (E, ?), asks if the ground set E contains ? disjoint k-subsets that are not in ?, and obtain a complexity trichotomy result for all pairs of k ? 1 and d ? 0. Our algorithmic result yields a sufficient and necessary condition that decides whether each hypergraph in some classes of r-uniform hypergraphs has a perfect matching, which has a number of algorithmic applications

Effects of human parvovirus B19 VP1 unique region protein on macrophage responses

<p>Abstract</p> <p>Background</p> <p>Activity of secreted phospholipase A (sPLA2) has been implicated in a wide range of cellular responses. However, little is known about the function of human parvovirus B19-VP1 unique region (VP1u) with sPLA2 activity on macrophage.</p> <p>Methods</p> <p>To investigate the roles of B19-VP1u in response to macrophage, phospholipase A2 activity, cell migration assay, phagocytosis activity, metalloproteinase assay, RT-PCR and immunoblotting were performed.</p> <p>Results</p> <p>In the present study, we report that migration, phagocytosis, IL-6, IL-1β mRNA, and MMP9 activity are significantly increased in RAW264.7 cells by B19-VP1u protein with sPLA2 activity, but not by B19-VP1uD175A protein that is mutated and lacks sPLA2 activity. Additionally, significant increases of phosphorylated ERK1/2 and JNK proteins were detected in macrophages that were treated with B19-VP1u protein, but not when they were treated with B19-VP1uD175A protein.</p> <p>Conclusion</p> <p>Taken together, our experimental results suggest that B19-VP1u with sPLA2 activity affects production of IL-6, IL-1β mRNA, and MMP9 activity, possibly through the involvement of ERK1/2 and JNK signaling pathways. These findings could provide clues in understanding the role of B19-VP1u and its sPLA2 enzymatic activity in B19 infection and B19-related diseases.</p

Stability evaluation of inactivated influenza H7N9 vaccines derived from adhesion and suspension MDCK cells

In recent years, cell-based manufacturing processes for influenza vaccine production has gained a great interest over the egg-based process. We have adapted MDCK cells to grow in chemical-defined medium and found this newly suspension MDCK cell line (sMDCK cells) is very suitable for the production of influenza virus. However, the property of purified antigens from sMDCK cells remains unclear. In this study, a stability program of influenza H7N9 vaccine (NIBRG268 vaccine strain) produced by sMDCK cells was investigated, and the data were compared with the vaccine derived from adhesion MDCK (aMDCK) cells in serum-free medium. The H7N9 bulks (with different storage time) derived from sMDCK and aMDCK cells were stored at 2-8°C for some times, and a number of parameters were used to monitor the H7N9 vaccine antigen stability was evaluated at different periods (1, 2, 3 and 6 months). The monitoring parameters are including virus structure, HA titer, HA content, total protein level, antigenicity, and immunogenicity. The sMDCK-derived H7N9 bulk showed similar virus structure to that aMDCK-derived H7N9 bulk, and there was no obvious change after further 6 months of storage. Furthermore, HA titer, HA content and total protein level of sMDCK- and aMDCK-derived H7N9 bulks were stable after 6 months of storage. sMDCK- and aMDCK-derived H7N9 bulks displayed similar antigenicity detected by hemagglutination inhibition (HI) test using standard serum. Finally, the results of HI and neutralization tests showed that sMDCK- and aMDCK-derived H7N9 vaccines were similar in immunogenicity in BALB/c mice vaccinated with 0.2 μg of H7N9 vaccine with an adjuvant of aluminum hydroxide. These results indicate that sMDCK-derived H7N9 bulk has good stability data similar to the aMDCK-derived H7N9 bulk. Thus, the newly developed suspension MDCK cells show a great market potential over the traditional vaccine manufacturing methods

Detecting P2P Botnet in Software Defined Networks

Software Defined Network separates the control plane from network equipment and has great advantage in network management as compared with traditional approaches. With this paradigm, the security issues persist to exist and could become even worse because of the flexibility on handling the packets. In this paper we propose an effective framework by integrating SDN and machine learning to detect and categorize P2P network traffics. This work provides experimental evidence showing that our approach can automatically analyze network traffic and flexibly change flow entries in OpenFlow switches through the SDN controller. This can effectively help the network administrators manage related security problems