Experimental study on age and gender differences in microscopic movement characteristics of students

Campus security has aroused many concerns from the whole society. Stampede is one of the most frequent and influential accidents in campus. Studies on pedestrian dynamics especially focusing on students are essential for campus security, which are helpful to improve facility design and emergency evacuation strategy. In this paper, primary and middle school students were recruited to participate in the single-file experiments. The microscopic movement characteristics,including walking speed, headway, gait characteristics(step length, step frequency and swaying amplitude) and their relations were investigated. Age and gender differences in the headway-speed diagram and space requirements were analyzed by statistical tests. The results indicated that the impacts of age and gender were significant. There were three stages for the influence of gender on the headway-speed diagram for both age groups. The impacts on students' space requirements were consistent for different age and gender groups. But the impacts of age and gender on free-flow speed were affected by each other. Due to the connection of walking speed and gait characteristics, the comparisons of gait characteristics between different ages and genders were performed to understand the corresponding differences in speed more deeply. The results showed that differences in step length and swaying amplitude between males and females were significant for both age groups. The effect of gender on step frequency was significant for primary students. But for middle school students,whether gender had significant impact on step frequency was not clear here because of the large P-value. Besides, the influence of age on gait characteristics changed with gender.     

Multiple re-configurable intelligent surfaces based physical layer eavesdropper detection for V2I communications

Inspired by the promising potential of re-configurable intelligent surface (RIS)-aided transmission in achieving the vision of 6th Generation (6G) network, we analyze the security model for a vehicular-to-infrastructure (V2I) network by considering multiple RISs (M-RIS) on buildings to act as passive relays at fixed distances from a source. In addition, multiple eavesdroppers are presented in the vicinity of the intended destination. Our aim is to enhance the secrecy capacity (SC) and to minimize secrecy outage probability (SOP) in presence of multiple eavesdroppers with the help of M-RIS in V2I communications. We propose a key-less physical layer security using beam-forming by exploiting M-RIS. The proposed approach assumes the concept of detecting eavesdroppers before the information can be transmitted via beam-forming by utilizing M-RIS. The results reveal that with consideration of M-RIS and beam-forming, the achievable SC and SOP performance is significantly improved while imposing minimum power consumption and fewer RIS reflectors.     

Intelligent resource allocation for transmission security on IRS-assisted spectrum sharing systems with OFDM

In this paper, intelligent reflecting surface (IRS) technology is employed to enhance physical layer security (PLS) for spectrum sharing communication systems with orthogonal frequency division multiplexing (OFDM). Aiming to improve the secondary users’ secrecy rates, a design problem for jointly optimizing the transmission beamforming of secondary base station (SBS), the IRS’s reflecting coefficient and the channel allocation is formulated under the constraints of the requirements of minimum data rates of primary users and the interference between users. As the scenario is highly complex, it is quite challenging to address the non-convexity of the optimization problem. Thus, a deep reinforcement learning (DRL) based approach is taken into consideration. Specifically, we use dueling double deep Q networks (D3QN) and soft Actor–Critic (SAC) to solve the discrete and continuous action space optimization problems, respectively, taking full advantage of the maximum entropy RL algorithm to explore all possible optimal paths. Finally, simulation results show that our proposed approach has a great improvement in security transmission rate compared with the scheme without IRS and OFDM, and our proposed D3QN-SAC approach is more effective than other approaches in terms of maximum security transmission rate.     

Secrecy energy efficiency optimization for multiuser massive MIMO wiretap systems with transmit antenna selection

Massive multiple-input-multiple-output (Massive MIMO) significantly improves the capacity of wireless communication systems. However, large-scale antennas bring high hardware costs, and security is a vital issue in Massive MIMO networks. To deal with the above problems, antenna selection (AS) and artificial noise (AN) are introduced to reduce energy consumption and improve system security performance, respectively. In this paper, we optimize secrecy energy efficiency (SEE) in a downlink multi-user multi-antenna scenario, where a multi-antenna eavesdropper attempts to eavesdrop the information from the base station (BS) to the multi-antenna legitimate receivers. An optimization problem is formulated to maximize the SEE by jointly optimizing the transmit beamforming vectors, the artificial noise vector and the antenna selection matrix at the BS. The formulated problem is a nonconvex mixed integer fractional programming problem. To solve the problem, a successive convex approximation (SCA)-based joint antenna selection and artificial noise (JASAN) algorithm is proposed. After a series of relaxation and equivalent transformations, the nonconvex problem is approximated to a convex problem, and the solution is obtained after several iterations. Simulation results show that the proposed algorithm has good convergence behavior, and the joint optimization of antenna selection and artificial noise can effectively improve the SEE while ensuring the achievable secrecy rate.     

稀土安全评价:集成算法改进与实证

稀土作为我国战略性矿产资源,其安全问题一直是政府和学术界关注与研究的重要课题.建立了稀土安全的概念框架与评价体系,针对传统AHP中九标度法的不足,基于熵值法、加速遗传算法及扩充标度值的层次分析法,提出了一种改进的层次分析法(EV-AGA-EAHP),通过集成模糊C-均值聚类算法和模糊综合评价法,研究提出了一种模糊综合集成评价方法(EV-AGA-EAHP-FCM-FIJ),给出了集成算法及步骤,对2001-2013年我国稀土安全水平进行了评价,提出了保障我国稀土安全的建议.     

基于权重比的民航飞行员安全行为指标权重算法

确定飞行员安全行为指标的权重,对发现民航飞行员飞行安全风险的短板,提高民航飞行安全性具有重要意义.基于指标权重比,提出了一种飞行员安全行为指标权重算法.并以此算法分析了职业安全意识、飞行情景意识、特情应变能力以及机组资源管理能力等指标对飞行员安全行为的影响程度,研究可为飞行员安全行为风险管理提供依据,对安全飞行具有积极的指导意义.     

基于个体仿真的机场安检系统优化研究

建立了安检流程的网络流模型,模型中包含了不稳定的乘客到达情形、嫌疑乘客以及反馈机制。分析了安检过程中的瓶颈所在,并给出了相应的优化方案,包括整个安检过程的通行规则,A区和B区内部预检节点与普通节点的适当比例等。仿真结果显示,为了充分利用安检资源并兼顾预检乘客的利益,通行规则应采用连通方案。依照统计数据中计算出的各种参数,在A区预检节点和普通节点比例设置为2∶2,B区预检节点和普通节点比例设置为3∶5的情况下,旅客平均等待时间最短,等待时间的标准差也最小,同时高峰期的通行量也相对较优。进一步分析了不同的文化背景及机场情况。对于美国人和瑞士人,通过改变预检乘客的选择概率来满足他们不同的行为偏好。仿真结果说明,预检乘客选择哪类节点进行安检对平均等待时间、等待时间的标准差和高峰期通行量的影响不大。分析了插队情形,插队对平均等待时间和高峰期通行量几乎没有影响,但当插队比例非常大时,旅客等待时间标准差会增加,影响乘客到达的准确性。最后,针对具体情况提出了一些合理的建议,并给出了进一步的研究计划。     

Nutritional potential of edible Russula species from Alédjo Wildlife Reserve (AWR)

In order to contribute to the valorisation of wild fungi whose nutritional potential, although considerable, is not sufficiently known in some countries such as Togo, a study has been carried out on Russula species. The diversity of Russula species from Alédjo Wildlife Reserve has been assessed using a focused inventory in woodlands dominated by Isoberlinia doka Craib & Stapf, Isoberlinia tomentosa (Harms) Craib & Stapf, Monotes kerstingii Gilg, Uapaca togoensis Pax and gallery forests dominated by Berlinia grandiflora (Vahl) Hutch & Dalz and Uapaca guineensis Müll. Ethnomycological surveys have been carried out among Tém and Kabyè, two riparian ethnic groups that are mainly represented. Biochemical analyses have been carried out using the AOAC method. Fifteen (15) taxa of edible Russula species are commonly used by Tém and Kabyè people living along the Alédjo Wildlife Reserve among which thirteen (13) taxa have been identified up to species level. R. oleifera is eaten by all interviewed people in both sociolinguistic groups (Fr = 100%) followed by R. compressa (Fr = 92.31%), R. ochrocephala (Fr = 87.18%) among Tém people and R. ochrocephala (Fr = 91.67%), R. compressa (Fr = 83.33%) among Kabyè people. Five (05) new species of edible Russula have been identified for the first time in Togo. The Russula species analysed have been rich in macronutrients with contents ranging from 2.88 g/100 g of dw for fat to 65.83 g/100 g of dw for total carbohydrates. In addition, these Russula species have shown a relatively high mineral content with contents ranging from 405.70 mg/100 g of dw for Ca to 2784 mg/100 g of dw for K. Furthermore, the results have revealed that Russula species analysed are a source of energy with 309.50 Kcal/100 g of dw. The edible Russula species analysed can thus contribute to food security in Togo.     

Quantum Hacking on an Integrated Continuous-Variable Quantum Key Distribution System via Power Analysis

In quantum key distribution (QKD), there are some security loopholes opened by the gaps between the theoretical model and the practical system, and they may be exploited by eavesdroppers (Eve) to obtain secret key information without being detected. This is an effective quantum hacking strategy that seriously threatens the security of practical QKD systems. In this paper, we propose a new quantum hacking attack on an integrated silicon photonic continuous-variable quantum key distribution (CVQKD) system, which is known as a power analysis attack. This attack can be implemented by analyzing the power originating from the integrated electrical control circuit in state preparation with the help of machine learning, where the state preparation is assumed to be perfect in initial security proofs. Specifically, we describe a possible power model and show a complete attack based on a support vector regression (SVR) algorithm. The simulation results show that the secret key information decreases with the increase of the accuracy of the attack, especially in a situation with less excess noise. In particular, Eve does not have to intrude into the transmitter chip (Alice), and may perform a similar attack in practical chip-based discrete-variable quantum key distribution (DVQKD) systems. To resist this attack, the electrical control circuit should be improved to randomize the corresponding power. In addition, the power can be reduced by utilizing the dynamic voltage and frequency scaling (DVFS) technology.     

Secure Polar Coding for the Primitive Relay Wiretap Channel

With the emergence of wireless networks, cooperation for secrecy is recognized as an attractive way to establish secure communications. Departing from cryptographic techniques, secrecy can be provided by exploiting the wireless channel characteristics; that is, some error-correcting codes besides reliability have been shown to achieve information-theoretic security. In this paper, we propose a polar-coding-based technique for the primitive relay wiretap channel and show that this technique is suitable to provide information-theoretic security. Specifically, we integrate at the relay an additional functionality, which allows it to smartly decide whether it will cooperate or not based on the decoding detector result. In the case of cooperation, the relay operates in a decode-and-forward mode and assists the communication by transmitting a complementary message to the destination in order to correctly decode the initial source’s message. Otherwise, the communication is completed with direct transmission from source to the destination. Finally, we first prove that the proposed encoding scheme achieves weak secrecy, then, in order to overcome the obstacle of misaligned bits, we implement a double-chaining construction, which achieves strong secrecy.