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Recent spacecraft attitude control systems tend to use wireless communication for cost-saving and distributed mission purposes while encountering limited communication resources and data exposure issues. This paper aims to study the attitude control problem with low communication frequency under the sampled-data.

The authors propose constructive control system structures based on quantization and event-triggered methods for intra-spacecraft and multi-spacecraft systems, and they also provide potential solutions to shield the control system's data security. The proposed control architectures can effectively save communication resources for both intra-spacecraft and multi-spacecraft systems.

The proposed control architectures no longer require sensors with trigger-ing mechanism and can achieve distributed control schemes. This paper also provides proposals of employing the public key encryption to secure the data in control-loop, which is transmitted by the event-triggered control mechanism.

Spacecraft attempts to use wireless communication, yet the attitude control system does not follow up promptly to accommodate these variations. Compared with existing approaches, the proposed control structures can save communication resources of control-loop in multi-sections effectively, and systematically, by rationally configuring the location of quantization and event-triggered mechanisms.

This paper presents several new control schemes and a necessary condition for the employment of encryption algorithms for control systems based on event-based communication.

The purpose of this paper is to study the general actuator modeling in spacecraft attitude control systems.

The proposed module in this paper provides various non-ideal factors such as the second-order dynamic time response, time-delay, bias torques, dead-zones and saturation. The actuator module can make the simulation as close to the practical situation as possible.

This paper presents a practical integrated module for the simulation of attitude control algorithms. Based on theoretical modeling, we give simulation modules and numerical examples. The proposed model can be directly used in spacecraft control simulation. Instead of considering only a few of them, it makes the simulation more convincing. Though it may not be perfect, it is better than totally ignoring the actuator dynamics.

The authors provide an integrated actuator model for spacecraft attitude control simulation, considering as many nonlinear factors as possible once time.

The purpose of this paper is to investigate the attitude cooperation control of multi-spacecraft with in-continuous communication.

A decentralized state-irrelevant event-triggered control policy is proposed to reduce control updating frequency and further achieve in-continuous communication by introducing a self-triggered mechanism.

Each spacecraft transmits data independently, without the requirement for the whole system to communicate simultaneously. The local predictions and self-triggered mechanism avoid continuous monitoring of the triggering condition.

This investigation is suitable for small Euler angle conditions.

The control policy based on event-triggered communication can provide potential solutions for saving communication resources.

This investigation uses event- and self-triggered policy to achieve in-communication for the multi-spacecraft system.

The purpose of this study was to develop a new approach using a pulse YAG laser with rational power density and pulse width to texture desired discrete distribution morphology on the cylinder wall.

Variational rules of the effects of these three parameters were found by calculating the oil film on the cylinder/piston ring system. The experiment results were compared between laser texturing cylinders and conventional honing cylinders.

It was found that the coefficient of friction and wear rate of laser texturing cylinders were reduced by 50 and 85.7 per cent, respectively, and the piston ring wear rate was decreased by 50 per cent under full lubrication condition. Under starved lubrication condition, the cylinder liner wear was reduced by 34.3 per cent.

The effectiveness of which was determined by three control parameters: depth-to-diameter ratio, area density and distribution angle of the dimples.

Since China’s “opening-up” in the late 1970s, Singapore has played a major role in enhancing China’s engagement with the world, especially in economic terms. This traditional relationship is well manifested in the third government-to-government (G–G) project under the BRI, which is known as the Chongqing Connectivity Initiative (CCI). The purpose of this paper is to address the following question: despite Singapore’s initial reluctance to agree on a third G–G project with China, why did Singapore eventually decide to join the CCI?

This paper draws on archives of over 700 Chinese language media reports and over 400 English language media reports, as well as private interactions with scholars interested in Sino-Singapore relations and with both sides’ officials in charge of the CCI project.

The paper finds that it is the goal of connecting the region, along with the need to maintain Singapore’s relevance to China and the regional economy that led to Singapore’s participation in the third G–G project. This paper also uses this case to analyse the changes that are taking place in the bilateral economic relations.

Despite wide media coverage, op-ed commentaries and respective government statements, there are a limited number of academic studies on the rationale of the third G–G project and contemporary Sino-Singapore relations in the literature. The scholarship has not addressed the rationale for Singapore’s changing attitude towards CCI and the manner in which the CCI has improved cooperation (or upgraded cooperation to a broader and regional level).

A qualitative development is discernible in China’s pursuit of global influence in knowledge following the launch of the Belt and Road Initiative (BRI). China has embarked on expanding the frontiers of its higher education and research enterprise in different geographies, a subset of its global power project. This paper employs the geointellect concept to analyze this phenomenon.

The paper applies the geointellect model, formed inductively, to illuminate China’s geographical expanse in higher education and research.

The BRI has provided a platform for China to shape the educational architecture of the participating countries, apart from receiving a boost in its prestige by leading educational alliances and opening overseas research centres. In quantitative terms, it has made progress in specific knowledge metrics. Nevertheless, certain challenges and limitations need to be overcome.

The role of a foreign policy in boosting a country’s knowledge profile has been identified. Future research directions have been provided in using the geointellect model.

This study provides a direction to evaluate the implications of China’s foreign policy for its knowledge segment, especially in terms of capturing its leading prowess in higher education and research.

It contributes a conceptual model to capture the different facets of China’s geointellect, with foreign policy, geography, higher education, and research being its constituents.