In this paper, we propose a novel physical layer security optical transmission scheme utilizing randomized quantization noise. The proposed approach encrypts low-order plaintext signals into ultra-high-order ciphertext using principles similar to quantum noise stream cipher (QNSC). While, the ultra-dense quadrature amplitude modulation (QAM) ciphertext waveforms are masked by intrinsic quantization noise. The combination of digital delta-sigma quantization and analog chaotic random scrambling not only produces randomized quantization noise, but also naturally supports one-time processing of masking ciphertext and generating keystream. Whereby, the in-band quantization noise (IBN) conceals nearby ciphertext levels bolstering security, and the out-of-band quantization noise (OOBN) is digitized to generate keystream using the Toeplitz hashing extractor. Experimental results show that 256-QAM plaintext signals were securely transmitted over standard single-mode fiber: 163-Gbps signals over 400 km, and 79.7-Gbps signals over 1800 km. To evaluate system performance, theoretical models for signal-to-noise ratio (SNR), bit error rate (BER), and number of masked signals (NMS) are derived as functions of the oversampling ratio (OSR). Our findings reveal a trade-off between transmission performance and security performance. Our results confirm that this scrambling effectively eliminates the correlation between the masking noise components. Toeplitz hashing extractor can effectively reduce the complexity of keystream generation and obtain a source-independent random keystream.

The work is centered on developing a constructive method of synthesizing an output-feedback second-order sliding-mode (SOSM) controller. By leveraging a coordinate transformation and revamping the technique of adding a power integrator, a state-feedback SOSM controller is first constructed under the full-state measurement. In order to tackle the challenge posed by the unmeasurable first derivative of the sliding variable, a discontinuous observer with appropriately selected scaling gains is put forward to overcome the measurable lack. Through the interactive cooperation of the state-feedback SOSM controller and the discontinuous observer, an output-feedback SOSM controller is successfully designed without reliance upon the separation principle. The finite-time convergence of the whole system is rigorously validated by dint of the Lyapunov function-based analysis. The efficiency of the theoretical results is ultimately corroborated through a simulation study.

In order to model and study the interactions between social on technical systems, a systemic method, namely the composite socio-technical systems (CSTS), is proposed to incorporate social systems, technical systems and the interaction mechanism between them. A case study on University of Denver (DU) campus grid is presented in paper to demonstrate the application of the proposed method. In the case study, the social system, technical system, and the interaction mechanism are defined and modelled within the framework of CSTS. Distributed and centralized control and management schemes are investigated, respectively, and numerical results verifies the feasibility and performance of the proposed composite system method.