In this paper, an efficient data structure for storage, management, and security in blockchain systems is presented. This efficient structure is based on the AVL (Adelson-Velsky and Landis) tree and make an extension for the purpose of management and security. We first present a new storage structure for efficient data search based on the AVL tree. Next we expand this data structure and apply to the management and security of the blockchain ledger. The way of management for distributed account/data is divided into two operations, namely splitting and merging. This paper also makes a discussion about the significance of these two operations. We show a detailed description and make mathematical analysis with proof for the performance of all mechanisms proposed in this paper. In addition, a mechanism of dual authentication is also proposed and to provide a better tamper-proof.

This paper is mainly to study how to provide realtime communication services among multiple blockchain information systems. We first described the concept and defined the model of inter-blockchain networks. Next, the algorithmic concept and the formal algorithm are presented. The output of the algorithm is a tree connection, i.e., a Multicast Routing Tree (MRT). The MRT not only can satisfy both the specified realtime and bandwidth-requirement constraints but also has high degree of resource sharing in terms of the tree cost. We also made an analysis and correctness proof to our proposed algorithm. Our algorithm was implemented and simulated, the results showed a good performance relative to the well-known BSMA and SPT algorithms. We made a conclusion in the final.

In vehicular ad‐hoc networks, high mobility tends to break established paths and cause bandwidth waste because of path reconstruction. To improve the situation, this study presents a new position‐based protocol. The new protocol uses control packets to collect approaching‐the‐junction information and, based on the information, lets moving vehicles adapt their routing paths dynamically when arriving at a junction. Compared with existing protocols which pre‐store massive routing paths in a vehicle, the protocol can accurately relay packets to the destination by significantly reduced control packets. Transmission efficiency is therefore enhanced. Performance evaluation exhibits that the proposed protocol is suitable for practice in highly topology‐changing vehicle‐to‐vehicle environments because it can accurately select targets for packet relay at less routing and storage cost.

In this correspondence, we first point out an error in Jia's algorithm (1998) by a counterexample. Second, we provide a fix and make an improvement to the part of Dynamic-Join. Finally, we give an analysis and a correctness proof of our algorithm.