PurposeThe paper seeks to investigate how culture, attitudes and barriers affect knowledge sharing in a Hong Kong government department.Design/methodology/approachInterviews and survey instruments were used to collect data for qualitative analysis.FindingsKnowledge management and knowledge sharing were welcome ideas in the Hong Kong government department. Informal and tacit knowledge sharing took place but the Chinese culture remained as a barrier to knowledge sharing.Research limitations/implicationsAs this is a study of one government department in one particular country, the findings may not be sufficiently generalizable.Practical implicationsSenior management in the public administration sector should be made more aware of what knowledge management can do to help improve organizational efficiency and effectiveness.Originality/valueThe study is an in‐depth analysis of one large government department's use of knowledge management, which has not been studied before. This study and its findings contribute significantly to the knowledge of how culture will affect knowledge management in the public administration sector.

Abstract-Jamming resistance is crucial for applications where reliable wireless communication is required. Spread spectrum techniques such as Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS) have been used as countermeasures against jamming attacks. Traditional antijamming techniques require that senders and receivers share a secret key in order to communicate with each other. However, such a requirement prevents these techniques from being effective for anti-jamming broadcast communication, where a jammer may learn the shared key from a compromised or malicious receiver and disrupt the reception at normal receivers.In this paper, we propose a Randomized Differential DSSS (RD-DSSS) scheme to achieve anti-jamming broadcast communication without shared keys. RD-DSSS encodes each bit of data using the correlation of unpredictable spreading codes. Specifically, bit "0" is encoded using two different spreading codes, which have low correlation with each other, while bit "1" is encoded using two identical spreading codes, which have high correlation. To defeat reactive jamming attacks, RD-DSSS uses multiple spreading code sequences to spread each message and rearranges the spread output before transmitting it. Our theoretical analysis and simulation results show that RD-DSSS can effectively defeat jamming attacks for anti-jamming broadcast communication without shared keys.

Semiconductor photocatalysis is currently attracting tremendous attention as it holds great potential to address the issues of energy shortage and environmental pollution. 2D materials are excellent candidates for photocatalysis owing to their attractive structural and electronic properties. However, practical applications of 2D materials are still hindered due to limitations, such as fast electron–hole recombination and poor redox ability, both of which lead to low efficiency of photocatalytic reactions. Constructing a heterojunction is the most widely used strategy to solve these problems. In particular, heterojunctions composed of 2D materials interfaced with other semiconductors of different dimensionalities can integrate the respective advantages and mitigate the drawbacks of each component. Hence, this review focuses on the recent developments in the rational design of 2D material‐based heterojunction photocatalysts with different configurations. The synthetic strategies, physicochemical properties, component functions, photocatalytic mechanisms, and applications of these heterojunctions are systematically summarized. Emphasis is placed on correlations between photocatalytic performance and heterojunction configuration. Finally, the ongoing challenges and potential directions for future development of 2D material‐based heterojunction photocatalysts are also proposed.

At present, with the development of an aging society and an increase in the number of elderly people, in order to ensure the ability and enthusiasm of the elderly to live independently, it is necessary to ensure that they can understand the world in a normal way. More and more elderly people have cognitive impairment, and virtual reality (VR) technology is more effective in cognitive diagnosis and treatment than traditional methods. This review article describes some studies on cognitive diagnosis and training for the elderly, and puts forward some suggestions for current studies, in the hopes that VR technology can be better applied to cognitive diagnosis and training.