**5. Conclusions**

When facing real-time data updating in the era of big data, how to deal with data effectively which are generated at any time has become one of the key issues. In this paper, the concept of consistency is introduced as a prerequisite for the uniting of interval concept lattices. Lateral uniting of interval concept lattices can be carried out when the parameter intervals of two interval concept lattices are identical and the object sets are identical. In order to preserve the integrity of the lattice structure, the concepts in lattice structures are divided into three categories: Existential concept, redundant concept and empty concept by improving the progressive generation algorithm of interval concept lattices. The concept of *<sup>L</sup>*(*<sup>U</sup>*, *A*, *R*) is introduced at the same time. Lateral uniting of lattice structures is specified to the horizontal uniting of lattice nodes. It can be divided into two situations, that is, the number of connotative attributes of concepts in the original structure equals the number of conceptual layers and the sum of the number of connotative attributes of concepts in the two original structures equals the number of conceptual layers, and the two cases are further refined according to the actual situation, so as to realize the horizontal union of interval concept lattices.

However, in the face of large-scale data, the structure of the interval concept lattice will be greatly expanded, which will lead to high operational complexity. How to develop efficient dynamic uniting software of interval concept lattice, further reduce the complexity of time and space, realize the optimal merging of interval concept lattices, and proposing association rules from them will be the next major research work.

**Author Contributions:** Y.Y. contributed to the main body of the paper, the improved method of constructing the interval concept lattice, and the principle of dynamic combination. The main models and algorithms were constructed; R.Z. was mainly responsible for the writing of the paper, colleagues performed data processing and graphics drawing; B.L. guided the overall process of the paper, gave the definition of interval concept lattices, and points out the method and feasibility of the combination of interval concept lattices.

**Funding:** This research was funded by the National Natural Science Foundation of China (61370168, 61472340), Natural Science Foundation of Hebei Province (F2016209344).

**Acknowledgments:** The authors thank Chunying Zhang, Lihong Li and Bin Bai from North China University of Science and Technology for their technical assistance during materials processing and data acquisition.

**Conflicts of Interest:** The authors declare no conflicts of interest.
