This paper introduces a search-and-rescue robot system used for remote sensing of the underground coal mine environment, which is composed of an operating control unit and two mobile robots with explosion-proof and waterproof function. This robot system is designed to observe and collect information of the coal mine environment through remote control. Thus, this system can be regarded as a multifunction sensor, which realizes remote sensing. When the robot system detects danger, it will send out signals to warn rescuers to keep away. The robot consists of two gas sensors, two cameras, a two-way audio, a 1 km-long fiber-optic cable for communication and a mechanical explosion-proof manipulator. Especially, the manipulator is a novel explosion-proof manipulator for cleaning obstacles, which has 3-degree-of-freedom, but is driven by two motors. Furthermore, the two robots can communicate in series for 2 km with the operating control unit. The development of the robot system may provide a reference for developing future search-and-rescue systems.

Formation control is an important problem in cooperative robotics due to its broad applications. To address this problem, the concept of a virtual linkage is introduced. Using this idea, a group of robots is designed and controlled to behave as particles embedded in a mechanical linkage instead of as a single rigid body as with the virtual structure approach. As compared to the virtual structure approach, the method proposed here can reconfigure the group of robots into different formation patterns by coordinating the joint angles in the corresponding mechanical linkage. Meanwhile, there is no need to transmit all the robots' state information to a single location and implement all of the computation on it, due to virtual linkage's hierarchical architecture. Finally, the effectiveness of the proposed method is demonstrated using two simulations with nine robots: moving around a circle in line formation, and moving through a gallery with varying formation patterns.

Aims: Despite that vascular plants constitute an important component of overall global biodiversity and have been studied well over two centuries, the questions of "How many species of vascular plants are there in the world and how many of them have been discovered and described?" remain open. Here, we address the second of the two questions. Method: We synthesized four global plant databases.Results & Conclusions: Our study shows that for the entire global flora of vascular plants (including natural hybrids), 376,366 species have been discovered and validly described. When natural hybrids are excluded, the global flora includes 369,054 species of vascular plant species, of which pteridophytes (ferns and lycophytes), gymnosperms and angiosperms have 13,810, 1,172 and 354,072 species, respectively. The number of vascular plant species derived from our study is larger than any of the other four databases by at least 17,700 species.

There is a growing research interest in the topic of work engagement over the past years. In reference to Schauefeli, Salanova, Gonzalez-Roma & Bakker (2002) [1], work engagement is described as "a positive, fulfilling work-related state of mind that is characterized by vigor, dedication and absorption". As compare to the researches based on the relationship between work engagement and organizational commitment and job performance, the existing researches on the relationship between work engagement and turnover intentions are far fewer. We theoretically discussed the relationship among work engagement, affective commitment and turnover intentions. Research results show that work engagement is negatively related to turnover intentions whereby affective commitment plays a regulating role. Affective commitment moderates the relationship between work engagement and turnover intentions whereby employees' affective commitment is stronger and employees are more willing to invest effort in their work; hence, employees' turnover intentions are reduced.

This paper presents a novel sensing mode for using mobile robots to collect disaster ground information when the ground traffic from the rescue center to disaster site is disrupted. Traditional sensing modes which use aerial robots or ground robots independently either have limited ability to access disaster site or are only able to provide a bird’s eye view of the disaster site. To illustrate the proposed sensing mode, the authors have developed a Multi-robot System with Air Dispersal Mode (MSADM) by combining the unimpeded path of aerial robots with the detailed view of ground robots. In the MSADM, an airplane carries some minimal reconnaissance ground robots to overcome the paralyzed traffic problem and deploys them on the ground to collect detailed scene information using parachutes and separation device modules. In addition, the airplane cruises in the sky and relays the control and reported information between the ground robots and the human operator. This means that the proposed sensing mode is able to provide more reliable communication performance when there are obstacles between the human operators and the ground robots. Additionally, the proposed sensing mode can easily make use of different kinds of ground robots, as long as they have a compatible interface with the separation device. Finally, an experimental demonstration of the MSADM is presented to show the effectiveness of the proposed sensing mode.