A new artifact-based method to identify the systematic errors in multi-axis CNC machine tools minimizing the worst case prediction error is presented. The closed loop volumetric error is identified by simultaneously moving the axes of the machine tool. The physical artifact is manufactured on the machine tool and later measured on a coordinate measuring machine. The artifact consists of a set of holes in the machine tool workspace at locations that minimize the worst case prediction error for a given bounded measurement error. The number of holes to be drilled depends on the degree of the polynomials used to model the systematic error and the number of axes of the machine tool. The prediction error is also function of the number and location of the holes. The feasibility of the method is first investigated for a two-axis machine to find the best experimental setting. Finally based on the two-axis case study, we extend the results to machine tools with any number of axes. The obtained results are very promising and require only a short time to produce the artifact

This study explores the use of mobile phones for farm-related activities of ethnic minority farmers in Quang Tri province, Central Vietnam, in the context of the COVID-19 pandemic. A random sampling strategy was used to select 180 ethnic farmers, different by gender, age, and education level, to interview using a semi-structured questionnaire. Results indicate ethnic minority farmers used mobile phones for various purposes related to agriculture through phone calls and social media platforms (Facebook, Zalo, YouTube, etc.). Mobile phones have become essential for farmers to access and exchange market information, receive weather information, get extension advisories, learn new farming practices and technologies, contact and buy farm inputs, etc. There was a statistically significant association between gender, age, and education level with the purposes of mobile phone usage. Young and highly educated farmers should be prioritized in digital service development strategies since they are the pioneers who will be the leading groups of farmers in terms of using mobile phones for farm-related activities. Furthermore, the significance of female farmers’ mobile phone use should not be overlooked, as when women have access to these devices, they can use them for various farming tasks to improve their agricultural production.

Wax tree has been cultivated to get lacquer, a valuable source of material that is necessary for many industries and handicrafts. Evaluating not only phenotype but also genotype is essential in order to increase the efficiency of new breeding program. In this study, the genetic relationship at the molecular level of 90 wax trees collected in three regions, i.e., Tam Nong, Thanh Son (Phu Tho) and Chiem Hoa (Tuyen Quang), was analyzed by SSR and ScoT markers. The results revealed a significant diversity among the individuals, with similarity coefficient from 0.41 to 0.98. The sample group collected in Chiem Hoa was significantly different from that in Tam Nong. Most of samples which had a high level of genetic similarity, from 0.95 to 0.98, were pairs of samples at the same geographical origin. The high similarity degree of these samples is likely due to the practice of selecting seeds from high-yield wax tree to be kept for seeds. These results provide the necessary information for new wax tree breeding program.