Biblio

Ciphertext-policy attribute-based encryption (CP-ABE) is applied to many data service platforms to provides secure and fine-grained access control. In this paper, a new CP-ABE system based on the algebraic decision diagram (ADD) is presented. The new system makes full use of both the powerful description ability and the high calculating efficiency of ADD to improves the performance and efficiency of algorithms contained in CP-ABE. First, the new system supports both positive and negative attributes in the description of access polices. Second, the size of the secret key is constant and is not affected by the number of attributes. Third, time complexity of the key generation and decryption algorithms are O(1). Finally, this scheme allows visitors to have different access permissions to access shared data or file. At the same time, PV operation is introduced into CP-ABE framework for the first time to prevent resource conflicts caused by read and write operations on shared files. Compared with other schemes, the new scheme proposed in this paper performs better in function and efficiency.

Knowledge Tracing (KT) is a task that aims to assess students' mastery level of knowledge and predict their performance over questions, which has attracted widespread attention over the years. Recently, an increasing number of researches have applied deep learning techniques to knowledge tracing and have made a huge success over traditional Bayesian Knowledge Tracing methods. Most existing deep learning-based methods utilized either Recurrent Neural Networks (RNNs) or Convolutional Neural Networks (CNNs). However, it is worth noticing that these two sorts of models are complementary in modeling abilities. Thus, in this paper, we propose a novel knowledge tracing model by taking advantage of both two models via combining them into a single integrated model, named Convolutional Recurrent Knowledge Tracing (CRKT). Extensive experiments show that our model outperforms the state-of-the-art models in multiple KT datasets.