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From the aspect of bibliometrics and social network analysis, this paper studies the content characteristics and network evolution of service quality in China, form visual analysis charts and summarizes the research hotspots and development trends. Taking CNKI database as the data source, data mining and association analysis of sample data were carried out by means of manual judgment, keyword co-occurrence, bibliometric software BICOMB and Pajek. 872 related literatures were retrieved from 1999 to 2019, and the tendency of the number of published papers in each year was close to the inverted U type. This study expands the application fields of bibliometrics and social network software, and analyzes the development trend of service quality. The theoretical and practical research on service quality has achieved rapid development in the past 20 years. The library service quality and service quality satisfaction have always gotten a high level of attention, and the characteristics of network platforms for service quality have gradually become apparent because of the development of the Internet and computer technology.

To investigate the small-signal stability of automatic generation control (AGC) system with constant communication delay, this paper establishes its state-space based on Padé approximation and conducts eigenvalue calculation. Then, by tracking the change of eigenvalues with time delay, the time-delay margin can be confirmed. Different controller parameters have complex influence on time delay margin and damping performance, so this paper utilizes particle swarm optimization (PSO) to obtain the optimal PI controller parameters to derive delay margin largest and an ideal damping performance. Finally, the simulation studies verify the correctness of time-delay margin calculation and indicate the AGC system has an ideal damping performance with optimal PI controller parameters

The environmental control system in most commercial airliner cabins supplies air from shoulder and ceiling level and exhausts air at floor level on both sides of the cabin walls. The ventilation system mixes air in the cabins to create a relative uniform air temperature distribution which is great for passengers’ thermal comfort. However, the mixing ventilation also enhances airborne contaminant transfer. Many displacement ventilation methods have been proposed to use in aircraft cabins, but the disadvantages of the ventilation approach are usually creating draft on the passengers’ ankles and high air temperature stratification between passengers’ heads and feet. This investigation developed an aisle displacement ventilation (ADV) system which can reduce air temperature stratification effectively without occupying the legroom space under the seats, so it is good for passengers and crew members’ comfort and friendly for luggage storage, in addition, it can also be easily installed in aircraft cabins. By installing the system in a five-row, twin-aisle cabin mockup, our study found that the ADV system can create a low air velocity distribution in the cabin and can maintain an acceptable air temperature stratification without draft. The system created an uprising airflow which can effectively remove airborne contaminant which was generated from index passengers’ respiratory activities. The experimental data were used to validate a computational-fluid-dynamics (CFD) program. The validated CFD program was used to compare the ADV with under-seat displacement ventilation (USDV) and underfloor air distribution (UFAD) system along the aisles. The comparison results show that the ADV had obvious better thermal comfort than the other two systems, and the cabin air quality of the three ventilation systems was similar, all far better than the “perfectly-mixed” ventilated condition.

Prompt prediction of the airborne gaseous pollutant transport is important to design a safe and comfortable air environment in an aircraft cabin. This paper proposes a model based on Markov chain to fulfill the task, in which the gaseous pollutant can be released from a source with an arbitrary profile. The model first obtains the airflow field by CFD to construct a transport probability matrix of the gaseous pollutant, then predicts the concentration field at each time step when an impulse is released at the known source location using the transport probability matrix. Finally, detailed trace of the pollutant released from the source with an arbitrary profile can be reproduced by linear superposition. The above strategy is applied on a two-dimensional aircraft cabin with gaseous pollutant released from one passenger for 2s. Results show that the proposed model is able to correctly predict the gaseous pollutant transport in only a few minutes. More than 90% of the computing time can be saved comparing with that from CFD without sacrificing much accuracy.

Information and cyber security of Industrial Control Systems (ICS) has gained considerable importance. Situation Awareness (SA) is an exciting mechanism to achieve the perception, comprehension and projection of the ICS information security status. Based on the Purdue Enterprise Reference Architecture (PERA), a situation awareness framework for ICS is presented considering the ICS cyber kill chain. The proposed framework consists of IT SA Centre, OT SA Centre, and Comprehensive SA Centre. Comprehensive SA Centre is responsible for creating and maintaining an integrated and high level of security visibility into the whole environments. The introduced framework can be used to guide the development of the situation awareness infrastructure in organization with industrial control systems.

The combustion method, due to its convenience and high-efficiency in harmless treatment, has been widely used in disposal of wastewater. With a wastewater burner as the study case, we performed numerical simulation by the Fluent software, analyzed the flowing and combustion process of the wastewater samples in the burner, compared the combustion effect of different atomization conditions — the spray cone model (hollow cone model, solid cone model), the spray angle, non-uniform grain size, uniform grain size. The study aims to provide suggestions for design and selection of wastewater burners.

Subject to the blowing air, fungal spores can be aerosolized from the colonies growing on cooling coils. The blowing air may accelerate and decelerate when passing a coil. The caused spore detachment may be different, when the fungal colonies grow on different positions of the coil. This study investigated the aerosolization of Aspergillus niger spores from a colony on a circular tube in a wind tunnel. The colony was first cultured in the carved groove along the longitudinal tube, and then the spores were aerosolized by a gradual increase of the blowing air speed. The grown colony on four different positions of the coil surface were blown for aerosolization. In addition, the airflow surrounding the circular tube was numerically solved to estimate the drag force for aerosolization of the spores. The results revealed that the collected airborne spores when the colonies were located tangentially to the upcoming airflow were six to eight times of those when the colonies were located parallel with the upcoming airflow for both the 4-day-old and 10-day-old colonies. The local air speeds in different positions of the tube were highly different from the inlet air speed of the wind tunnel. Such difference should be accounted for when estimating the drag force to aerosolize the fungal spores on the coils.

Cabin ventilation is crucial for maintaining thermal comfort and air quality for passengers and crew. The genetic algorithm, proper orthogonal decomposition (POD), and adjoint method have been proposed to inversely design the cabin ventilation. However, each method has its cons and pros. This paper proposed to integrate the above three methods in cascades. The genetic algorithm was applied first in the first stage to roughly circumscribe the ranges of design parameters. Then POD was applied in the next stage to further narrow the ranges and estimate the optimal parametric sets for each design criterion. The estimated optimal design from POD was supplied to the adjoint method for fine tuning. The air-supply parameters of a five-row aircraft cabin were inversely designed to achieve the minimum absolute value of the predicted mean vote (PMV) and the minimum averaged mean age of air. The results showed that the integrated method was able to improve the design stage by stage. The integrated method has superior advantages to assure the optimal design while minimizing the computing expense.