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At present, most publish/subscribe middlewares suppose that there are equal Quality of Service (QoS) requirements for all users. However, in many real-world Internet of Things (IoT) service scenarios, different users may have different delay requirements. How to provide reliable differentiated services has become an urgent problem. The rise of Software-Defined Networking (SDN) provides endless possibilities to improve the QoS of publish/subscribe middlewares due to its greater programmability. We can encode event topics and priorities into flow entries of SDN switches directly to meet customized requirements. In this paper, we first propose an SDN-like publish/subscribe middleware architecture and describe how to use this architecture and priority queues supported by OpenFlow switches to realize differentiated services. Then we present a machine learning method using the eXtreme Gradient Boosting (XGBoost) model to solve the difficult issue of getting the queuing delay of switches accurately. Finally, we propose a reliable differentiated services guarantee mechanism according to the queuing delay and the programmability of SDN to improve QoS, namely, a two-layer queue management mechanism. Experimental evaluations show that the delay predicted by the XGBoost method is closer to the real value; our mechanism can save end-to-end delay, reduce packet loss rate, and allocate bandwidth more reasonably.

This paper attempts to answer the question: ‘why is research in further education largely undervalued by policy‐makers and practitioners alike?’ The paper adopts as a working definition that proposed by Stenhouse that, ‘research is systematic self‐critical enquiry’. It is noted that knowledge of, or based upon, research, is seldom valued within management studies as a key resource for managers. Significant contributory factors to the marginality of research on and within the further education sector are argued to be historical, structural and symbolic. A number of barriers to establishing a research culture in the sector are identified, which fall under the broad groupings of personnel, policy and climate. Drawing upon the management of change literature, the potential benefits of a research culture for further education are argued, and the prospects for establishing such a culture are assessed. Political constraint is held to be a key factor limiting the currency of further education located practitioner research.