Abstract-In this paper studying open vehicle routing problem, a taboo search algorithm for the open vehicle routing problem with hard time windows is proposed. After constructing a mathematical model for the problem, this paper focuses on the introduction of the design procedure of TS algorithm for solving the problem. In the searching process of this algorithm, infeasible solution is allowed by adding a penalizing factor, to reduce the probability of local optimal. The computational results are provided. It shows that in most of cases this algorithm can find better solutions.

In order to improve the reliability of distributed storage systems (DSS) and repair efficiency of failed nodes, a new coding scheme, termed as locally repairable codes (LRC) based on fractional repetition (FR) codes, is proposed in this paper. Specifically, the proposed LRC based on FR codes divide the nodes into multiple local groups, and the FR codes with repetition degree 2   are adopted in each local group. The LRC based on FR codes can achieve the exact repair for single failed node in the local group, and rapid repair for multiple failed nodes in DSS with lower repair locality. Furthermore, compared with Reed-Solomon (RS) codes and simple regenerating codes (SRC), the LRC based on FR codes have remarkable advantages in repair bandwidth overhead.

In order to improve the reliability and repair efficiency of distributed storage systems, minimum bandwidth regenerating (MBR) codes based on cyclic variable fractional repetition (VFR) codes are constructed in this thesis, which can repair failed nodes accurately. Specifically, in order to consider the imbalance of data accessed by the users, cyclic VFR codes are constructed according to that data with different heat degrees are copied in different repetition degrees. Moreover, we divide the storage nodes into groups, and construct MBR codes based on cyclic VFR codes to improve the file download speed. Performance analysis and simulation results show that, the repair locality of a single node failure is always 2 when MBR codes based on cyclic VFR codes are adopted in distributed storage systems, which is obviously superior to the traditional MBR codes. Compared with RS codes and simple regenerating codes, the proposed MBR codes based on cyclic VFR codes have lower repair locality, repair complexity and bandwidth overhead, as well as higher repair efficiency. Moreover, relative to FR codes, the MBR codes based on cyclic VFR codes can be applicable to more storage systems.