Distributed control of industrial robot systems using Petri net based multitask processing
In this paper, the methods of the modeling of the discrete event robotic manufacturing systems using Petri nets are considered, and a methodology of decomposition and coordination is presented for hierarchical and distributed control, where the cooperation of each controller is implemented so that the behavior of the overall system is the same as the centralized control system and the task specification is completely satisfied. First, a task specification is defined as a Petri net model at the conceptual level, and then transformed to the detailed Petri net representation of the subtasks. Finally, the overall Petri net is decomposed and the constituent subnets are assigned to local Petri net based controllers. The controllers are coordinated so that the decomposed transitions fire at the same time by the coordinator. System coordination algorithm through communication between the coordinator and the controllers, is presented. By the proposed method, modeling, simulation and control of large and complex manufacturing systems can be performed consistently using Petri nets.
Virtual game and collaborative learning for packaging design
This paper presents an application of VR game-based learning, VRGBL, for packaging Technology. The VRGBL was divided into two steps, Material Packaging, MP and Pattern Packaging, PP. In the MP, students are selected an appropriate material of packages for each products from program randomly, and the selecting steps were controlled by the system in which students must selected a correct material of each product. If they can select correctly, the system will show the result and score increase. On the other hand, if students select a wrong material, the system will give the students a warning and their scores will be deducted. For the second game, the PP was designed to let students to practice their thinking by finding and matching a Pattern model of an unknown package with a set of 3D packages with which are randomly selected from the system. If they cannot choose correctly, the score will be deducted from their total scores. In addition, the system also provides material and pattern packaging tutorial such as a material selecting and other information. After students pass the VRGBL game, they can understand in material packaging and can design the good pattern of packaging. Then this system was evaluated by five experts. The Index of item Objective Congruence (IOC) is .82. The program was corrected and improved before trial with a target group. The target groups of this study consisted of 40 packaging students, and they were selected by simple random sampling. This paper describes some approaches to provide the VR game-based learning system, discusses problems, experiences and presents an outlook for the virtual game and collaborative learning of packaging design for students in the future. However, the result showed that students can select the good packaging material and design the pattern in a good level. Finally, the assessments of the performance of the program are presented.
School Principals and Education Law: What do they know, what do they need to know?
Principals now work in complex and challenging environments where uncertainty and change are the hallmarks of their roles and responsibilities. As such, the knowledge and capability demands on principals have expanded, including those related to education law. While these matters attracted some research interest a number of years ago, there has been little recent work in the area of principals and education law. This article reports on an exploratory study into aspects of the legal knowledge held by Tasmanian government school principals, particularly concerning non-sexual physical contact between teachers and students. The research was undertaken using a small-scale, mixed-methods research design, which required principals to respond to various legal scenarios. Three key findings emerged from the study. First, principals used two different levels of working knowledge about education law  one related to legal problems, and the other to legally-related routine activities. Second, on the particular topic of physical contact, some knowledge held by principals was not legally accurate. Third, for major legal issues, participants indicated that they acquired access to information from legal experts. The situation for routine legal matters was less clear, although in-service training and practical experience were identified as potential sources of knowledge. Participants recognised the importance of a sound knowledge of education law, especially for dealing with security and safety issues and preferred to access further information through in-service training. Notably, the findings of the study are broadly consistent with those from earlier Australian and international research, suggesting that much remains to be done in the area of principals’ education law knowledge.