We present BigKV, a key-value cache specifically designed for caching large objects in an all-flash array (AFA). The design of BigKV is centered around the unique property of a cache: since it contains a copy of the data, exact bookkeeping of what is in the cache is not critical for correctness. By ignoring hash collisions, approximating metadata information, and allowing data loss from failures, BigKV significantly increases the cache hit ratio and keeps more useful objects in the system. Experiments on a real AFA show that our design increases the throughput by 3.1× on average and reduces the average and tail latency by 57% and 81%, respectively.

For long-distance flying, drones often need to charge their battery at quick battery-charging machines (QCMs) because of their limited battery capacity. If a drone individually chooses a QCM without any coordination, a drone network may experience QCM congestion when multiple drones select the same QCM. This QCM congestion may lead to an increasing drone traffic delay. In order to solve this problem, we propose a cloud-based drone navigation (CBDN) system for efficient drone battery charging in drone networks. In order to achieve this goal, the CBDN gathers drone traffic information and determines efficient drone routes so as to minimize the overall QCM congestion level for drone battery charging using cloud-based management. Our key idea is to find globally coordinated drone routes so as to minimize the total traffic delay in a drone network by reducing the overall QCM congestion level. In order to demonstrate the effectiveness of the proposed system, we evaluated the performance of CBDN by simulating a drone network under various network conditions. The simulation results show that CBDN is more efficient than the existing shortest-path-based drone route planning algorithms in terms of end-to-end traffic delay and QCM average utilization.

It is an important issue to provide resilient services in wireless networks where frequent frame errors are observed. In this paper, we propose a p-persistent frame replication scheme for resilient services in multi-radio wireless networks. In the p-persistent frame replication scheme, packets are transmitted over the primary link and the packets are redundantly sent over the secondary link with probability p. In addition, cooperative retransmission is devised to minimize the overhead in retransmission. Analytical expressions for the reliability, latency, and redundancy in the p-persistent frame replication scheme are derived and validated by extensive simulations. We also develop a binary search algorithm to obtain the optimal p to minimize the redundancy while satisfying the given latency and reliability requirements.

This paper suggests an architecture of DNS service system for IPv6 mobile ad-hoc network connected to the Internet. The resolution of DNS names of mobile nodes within mobile ad-hoc network is performed by multicast DNS and that of DNS names of nodes in the Internet is performed through DNS autoconfiguration of recursive DNS server. In the former, each mobile node plays a role of DNS name server for the DNS resource records associated with DNS name of which authority it has. The latter allows mobile node to receive the global Internet service, such as Web service, in IPv6 mobile ad-hoc network that is connected to the Internet. These two kinds of DNS name resolution are processed automatically without the intervention of users in mobile ad-hoc network.