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In meta-analysis of diagnostic test accuracy, summary receiver operating characteristic (SROC) is a recommended method to summarize the discriminant capacity of a diagnostic test in the presence of study-specific cutoff values and the area under the SROC (SAUC) gives the aggregate measure of test accuracy. SROC or SAUC can be estimated by bivariate modelling of pairs of sensitivity and specificity over the primary diagnostic studies. However, publication bias is a major threat to the validity of estimates in meta-analysis. To address this issue, we propose to adopt sensitivity analysis to make an objective inference for the impact of publication bias on SROC or SAUC. We extend Copas likelihood based sensitivity analysis to the bivariate normal model used for meta-analysis of diagnostic test accuracy to evaluate how much SROC or SAUC would change with different selection probabilities under several selective publication mechanisms dependent on sensitivity and/or specificity. The selection probability is modelled by a selection function on $t$-type statistic for the linear combination of logit-transformed sensitivity and specificity, allowing the selective publication of each study to be influenced by the cutoff-dependent $p$-value for sensitivity, specificity, or diagnostic odds ratio. By embedding the selection function into the bivariate normal model, the conditional likelihood is proposed and the bias-corrected SROC or SAUC can be estimated by maximizing the likelihood. We illustrate the proposed sensitivity analysis by reanalyzing a meta-analysis of test accuracy for intravascular device related infection. Simulation studies are conducted to investigate the performance of proposed methods., Comment: 32 pages, 4 figure, 5 tables in main text, 5 tables in supplementary file

Prospective registration of study protocols in clinical trial registries is a useful way to minimize the risk of publication bias in meta-analysis, and several clinical trial registries are available nowadays. However, they are mainly used as a tool for searching studies and information submitted to the registries has not been utilized as efficiently as it could. In addressing publication bias in meta-analyses, sensitivity analysis with the Copas selection model is a more objective alternative to widely-used graphical methods such as the funnel-plot and the trim-and-fill method. Despite its ability to quantify the potential impact of publication bias, a drawback of the model is that some parameters not to be specified. This may result in some difficulty in interpreting the results of the sensitivity analysis. In this paper, we propose an alternative inference procedure for the Copas selection model by utilizing information from clinical trial registries. Our method provides a simple and accurate way to estimate all unknown parameters in the Copas selection model. A simulation study revealed that our proposed method resulted in smaller biases and more accurate confidence intervals than existing methods. Furthermore, two published meta-analyses had been re-analysed to demonstrate how to implement the proposed method in practice.

MQTT protocol is a publish/subscribe message protocol based on TCP/IP protocol. It has the characteristics of low power consumption, scalability, openness and simplicity. HTTP protocol is an open and low-cost request/reply message protocol based on TCP/IP protocol. It is the main protocol of Internet communication, but it is not suitable for the environment of computing, processing and bandwidth limited. In this paper, a simplified wireless sensor network node was designed based on MQTT protocol. The node was designed to use the Arduino development environment and use the WiFi for networking. It has the characteristics of simple structure, low power consumption and so on. The design can be widely used in smart home, environmental monitoring and medical applications, and is the main contents of the Internet of things (IoT).

Under the advocacy of the international community, more and more research topics have been built around the ocean. This paper proposed an implementation scheme of marine wireless sensor network monitoring system based on LoRa and MQTT. Different from the traditional network architecture, the system was constructed by combining with two network forms, and according to their respective characteristics, the overall design followed the transition from LoRa to MQTT. We first used LoRa to interconnect the sensor nodes with the gateway, and on this basis, the collected data was sent to the server visualization platform through MQTT, the backend management server would continuously refresh the monitoring page. At the same time, the client could use a browser-based web application to directly access and call data for global maritime information monitoring. In the future, we will further improve the system and optimize the algorithm, to achieve more dimensions and deeper exploration of the underwater world.