Biblio

In-Band Full-Duplex (IBFD) Underwater Acoustic (UWA) communication technology plays a major role in enhancing the performance of Underwater acoustic sensor networks (UWSN). Self-Interference (SI) is one of the main inherent challenges affecting the performance of IBFD UWA communication. To reconstruct the SI signal and counteract the SI effect, this is important to estimate the short range channel through which the SI signal passes. Inaccurate estimation will result in the performance degradation of IBFD UWA communication. From the perspective of engineering implementation, we consider that the UWA communication modem shell has a significant influence on the short-range SI channel, which will limit the efficiency of self-interference cancellation in the analog domain to some degree. Therefore we utilize a simplified model to simulate the influence of the structure of the IBFD UWA communication modem on the receiving end. This paper studies the effect of acoustic-shell coupling on near-end self-interference signal of IBFD UWA communication modem. Some suggestions on the design of shell structure of IBFD UWA communication modem are given.

For the purpose of outdoor advertising market researching, AD images are recaptured and uploaded everyday for statistics. But the quality of the recaptured advertising images are often affected by conditions such as angle, distance, and light during the shooting process, which consequently reduce either the speed or the accuracy of the retrieving algorithm. In this paper, we proposed a hash retrieval method based on convolutional neural networks for recaptured images. The basic idea is to add a hash layer to the convolutional neural network and then extract the binary hash code output by the hash layer to perform image retrieval in lowdimensional Hamming space. Experimental results show that the retrieval performance is improved compared with the current commonly used hash retrieval methods.

Mobile edge computing (MEC), an emerging technology, has the characteristics of low latency, mobile energy savings, and context-awareness. As a type of access network, wireless mesh network (WMN) has gained wide attention due to its flexible network architecture, low deployment cost, and self-organization. The combination of MEC and WMN can solve the shortcomings of traditional wireless communication such as storage capacity, privacy, and security. In this paper, we propose a location-aware (LA) algorithm to cognize the location and a location-aware offloading policy (LAOP) algorithm considering the energy consumption and time delay. Simulation results show that the proposed LAOP algorithm can obtain a higher completion rate and lower average processing delay compared with the other two methods.

Compared with traditional databases such as Oracle database, SQL Server database and MySQL database, Dameng database is a domestic database with independent intellectual property rights. Combined with the security management of Dameng database and the requirement of database audit, this paper designs the security configuration baseline of Dameng database. By designing the security configuration baseline of Dameng database, the audit work of Dameng database can be carried out efficiently, and by analyzing the audit results, the security configuration baseline of Dameng database can be improved.

Microgrids' dependency on communication links exposes the control systems to cyber attack threats. In this work, instead of designing reactive defense approaches, a proacitve moving target defense mechanism is proposed for securing microgrid secondary frequency control from denial of service (DoS) attack. The sensor data is transmitted by following a Markov process, not in a deterministic way. This uncertainty will increase the difficulty for attacker's decision making and thus significantly reduce the attack space. As the system parameters are constantly changing, a gain scheduling based secondary frequency controller is designed to sustain the system performance. Case studies of a microgrid with four inverter-based DGs show the proposed moving target mechanism can enhance the resiliency of the microgrid control systems against DoS attacks.

Compared with traditional centralized control strategies, the distributed control systems significantly improve the flexibility and expandability of an modular multilevel converter (MMC). However, the stability issue in the MMC distributed control system with the presence of control loop coupling interactions is rarely discussed in existing research works. This article is to improve the stability of an MMC distributed control system by inhibiting the control conflict due to the coupling interactions among control loops with incomplete control information. By modeling the MMC distributed control system, the control loop coupling interactions are analyzed and the essential cause of control conflict is revealed. Accordingly, a control parameter design principle is proposed to effectively suppress the disturbances from the targeted control conflict and improve the MMC system stability. The rationality of the theoretical analysis and the effectiveness of the control parameter design principle are confirmed by simulation and experimental results.

With the explosive development of big data, it is necessary to sort the data according to their importance or priorities. The sources with different importance levels can be modeled by the multilevel diversity coding systems (MDCS). Another trend in future communication networks, say 5G wireless networks and Internet of Things, is that users may obtain their data from all available sources, even from devices belonging to other users. Then, the privacy of data becomes a crucial issue. In a recent work by Li et al., the secure asymmetric MDCS (S-AMDCS) with wiretap channels was investigated, where the wiretapped messages do not leak any information about the sources (i.e. perfect secrecy). It was shown that superposition (source-separate coding) is not optimal for the general S-AMDCS and the exact full secure rate region was proved for a class of S-AMDCS. In addition, a bound on the key size of the secure rate region was provided as well. As a further step on the SAMDCS problem, this paper mainly focuses on the key size characterization. Specifically, the constraints on the key size of superposition secure rate region are proved and a counterexample is found to show that the bound on the key size of the exact secure rate region provided by Li et al. is not tight. In contrast, tight necessary and sufficient constraints on the secrecy key size of the counterexample, which is the four-encoder S-AMDCS, are proved.

The major challenge of Real Time Protocol is to balance efficiency and fairness over limited bandwidth. MPTCP has proved to be effective for multimedia and real time networks. Ideally, an MPTCP sender should couple the subflows sharing the bottleneck link to provide TCP friendliness. However, existing shared bottleneck detection scheme either utilize end-to-end delay without consideration of multiple bottleneck scenario, or identify subflows on switch at the expense of operation overhead. In this paper, we propose a lightweight yet accurate approach, EMPTCP, to detect shared bottleneck. EMPTCP uses the widely deployed ECN scheme to capture the real congestion state of shared bottleneck, while at the same time can be transparently utilized by various enhanced MPTCP protocols. Through theory analysis, simulation test and real network experiment, we show that EMPTCP achieves higher than 90% accuracy in shared bottleneck detection, thus improving the network efficiency and fairness.

In this paper, we propose a new randomized response algorithm that can achieve differential-privacy and utility guarantees for consumer's behaviors, and process a batch of data at each time. Firstly, differing from traditional differential private approach-es, we add randomized response noise into the behavior signa-tures matrix to achieve an acceptable utility-privacy tradeoff. Secondly, a behavior signature modeling method based on sparse coding is proposed. After some lightweight trainings us-ing the energy consumption data, the dictionary will be associat-ed with the behavior characteristics of the electric appliances. At last, through the experimental results verification, we find that our Algorithm can preserve consumer's privacy without comprising utility.

Comparing with the traditional grid, energy internet will collect data widely and connect more broader. The analysis of electrical data use of Non-intrusive Load Monitoring (NILM) can infer user behavior privacy. Consideration both data security and availability is a problem must be addressed. Due to its rigid and provable privacy guarantee, Differential Privacy has proverbially reached and applied to privacy preserving data release and data mining. Because of its high sensitivity, increases the noise directly will led to data unavailable. In this paper, we propose a differentially private mechanism to protect energy internet privacy. Our focus is the aggregated data be released by data owner after added noise in disaggregated data. The theoretically proves and experiments show that our scheme can achieve the purpose of privacy-preserving and data availability.

In the information age of today, with the rapid development and wide application of communication technology and network technology, more and more information has been transmitted through the network and information security and protection is becoming more and more important, the cryptography theory and technology have become an important research field in Information Science and technology. In recent years, many researchers have found that there is a close relationship between chaos and cryptography. Chaotic system to initial conditions is extremely sensitive and can produce a large number of with good cryptographic properties of class randomness, correlation, complexity and wide spectrum sequence, provides a new and effective means for data encryption. But chaotic cryptography, as a new cross discipline, is still in its initial stage of development. Although many chaotic encryption schemes have been proposed, the method of chaotic cryptography is not yet fully mature. The research is carried out under such a background, to be used in chaotic map of the chaotic cipher system, chaotic sequence cipher, used for key generation of chaotic random number generators and other key problems is discussed. For one-dimensional chaotic encryption algorithm, key space small, security is not higher defect, this paper selects logistic mapping coupled to generate twodimensional hyper chaotic system as the research object, the research focus on the hyper chaotic sequence in the application of data encryption, in chaotic data encryption algorithm to make some beneficial attempts, at the same time, the research on applications of chaos in data encryption to do some exploring.

The digital authentication security technology is widely used in the current brand cosmetics as key anti-counterfeiting technology, yet this technology is prone to "false security", "hard security" and "non-security" phenomena. This paper researches the current cosmetics brand distribution channels and sales methods also analyses the cosmetics brands' demand for RFID technology anti-counterfeiting security system, then proposes a security system based on RFID technology for brand cosmetics. The system is based on a typical distributed RFID tracking and tracing system which is the most widely used system-EPC system. This security system based on RFID technology for brand cosmetics in the paper is a visual information management system for luxury cosmetics brand. It can determine the source of the product timely and effectively, track and trace products' logistics information and prevent fake goods and gray goods getting into the normal supply chain channels.

While information-theoretic security is stronger than computational security, it has long been considered impractical. In this work, we provide new insights into the design of practical information-theoretic cryptosystems. Firstly, from a theoretical point of view, we give a brief introduction into the existing information theoretic security criteria, such as the notions of Shannon's perfect/ideal secrecy in cryptography, and the concept of strong secrecy in coding theory. Secondly, from a practical point of view, we propose the concept of ideal secrecy outage and define a outage probability. Finally, we show how such probability can be made arbitrarily small in a practical cryptosystem.

In this paper, it is shown that the high automation level of the object-oriented modeling paradigm for physical systems can significantly rationalize the design procedure of fault detection and isolation (FDI) systems. Consequently, an object-oriented FDI method for complex engineering systems consisting of subsystems from different physical domains like mechatronic systems, commercial vehicles, and chemical process plants is developed. The mathematical composition of the objects corresponding to the subsystems results in a differential algebraic equation (DAE) that describes the overall system. This DAE is automatically analyzed and transferred into a set of residual generators that enable a two-stage FDI procedure for multiple fault modes.