ABSTRACT With the rapid growth of the robotics market, social robots have garnered increasing global attention. Investigating service innovation within the domain of social robots enables a better understanding of the field's developmental trajectory and emerging trends. Such insights can support enterprises and researchers in the development of innovative technologies and related applications. This study collected a total of 1406 abstracts related to social robots published over the past 15 years from the Web of Science journal database, which served as the primary research corpus. The thematic evolution of social robots was analysed from two perspectives: the evolution of thematic intensity and the evolution of thematic content. The findings are as follows: (1) In the early stages, research was predominantly focused on system technologies. As these technologies matured, they facilitated the diversification of research topics, leading to a relative decline in system technology research and a corresponding rise in studies from other domains. (2) The development of social robots has primarily followed three main trajectories: system technologies, research concerning children and research concerning the elderly. Subtopics such as healthcare, companionship, education, interaction and innovative applications in commercial services have evolved independently while also aligning with these major trajectories, resulting in a diversified research landscape.

This paper presents a class of binary maximum distance separable (MDS) array codes for tolerating disk failures in redundant arrays of inexpensive disks (RAID) architecture based on circular permutation matrices. The size of the information part is m/spl times/n, the size of the parity-check part is m/spl times/3, and the minimum distance is 4, where n is the number of information disks, the number of parity-check disks is 3, and (m+1) is a prime integer. In practical applications, m can be very large and n is from 20 to 50. The code rate is R=n/(n+3). These codes can be used for tolerating three disk failures. The encoding and decoding of the Reed-Solomon-like codes are very fast. There need to be 3mn XOR operations for encoding and (3mn+9(m+1)) XOR operations for decoding.

For pt.1 see ibid., vol.54, no.9, p.1071-1080 (2005). A new class of binary maximum distance separable (MDS) array codes which are based on circular permutation matrices are introduced in this paper. These array codes are used for tolerating multiple (/spl ges/ 4) disk failures in redundant arrays of inexpensive disks (RAID) architecture. The size of the information part is m /spl times/ n, where n is the number of information disks and (m + 1) is a prime integer; the size of the parity-check part is m /spl times/ r, the minimum distance is r + 1, and the number of parity-check disks is r. In practical applications, m can be very large and n ranges from 20 to 50. The code rate is R = n/(n+r). These codes can be used for tolerating up to r disk failures, with very fast encoding and decoding. The complexities of encoding and decoding algorithms are O(rmn) and O(m/sup 3/r/sup 4/), respectively. When r = 4, there need to be 9mn XOR operations for encoding and (9n + 95)(m + 1) XOR operations for decoding.