Abstract
Cyber-physical systems (CPSs) have grown exponentially and have been attracting a lot of attention over the last few years because of cyber and the physical (natural and human-made) components that are being tightly integrated into many systems. Smart or intelligent sensor networks should be provided with the 3C (computation, communication, and control) abilities. Emerging applications include transportation, energy, healthcare, manufacturing, entertainment, consumer electronics, environment monitoring, and many parts of our social infrastructure. There are eight papers selected for publication in this special issue. Most of the selected papers present the design and implementation of cyber-physical systems applied to several areas, including safety surveillances, rehabilitation, smart living space, and so on.
G. Manes et al. propose a continuous remote monitoring platform which consists of sensor nodes and a gateway. The sensor nodes deployed at the hazardous sites will forward data to the platform through the gateway to improve the transmission reliability. The proposed platform uses volatile organic compound (VOC) detectors which are able to perform real-time analysis in potentially hazardous sites at unprecedented time/space scale. Overall, the platform provides an easily deployable stand-alone infrastructure with a high degree of scalability and reconfigurability with minimal intrusiveness or obtrusiveness.
C.-M. Own proposes the pet care system by establishing a location-aware infrastructure such that pet owners can timely monitor the pet's situation. The system applies the concepts of CPS and provides pet owners with the ability to remotely obtain their pet information and control the smart home of the pet. To monitor the behavior of the pet, a sensor tag is fixed on the collar of the pet and a location-aware algorithm was proposed to improve the location accuracy of the pet. Based on the pet's behavior, an intelligent pet door and a smart pet feeder are implemented using smart-home technology. Consequently, the proposed system can meet the needs of many pet owners.
One important topic in CPS research is how to retrieve the events from massive amounts of sensor data and analyzing them with spatial, temporal, and other multidimensional information. L.-A. Tang et al. propose the concept of a typical cluster which is a model describing multidimensional features of a typical event. The typical clusters can be efficiently integrated into a hierarchical framework to form macroclusters for large-scale analytical queries. To retrieve significant macroclusters, the system employs a guided clustering algorithm to filter out the trivial results and thus guarantees the accuracy of significant clusters. The proposed mechanisms are evaluated on gigabyte-scale datasets from real applications and save considerable time cost of the baselines.
C.-Y. Lin et al. present the most important design requirements of CPS architectures and summarize key sensor network characteristics that can be leveraged in CPS designs. The authors review many well-known CPS application domains that depend on wireless sensor networks (WSNs) in their design architectures and implementations. The challenges that still need to be addressed to enable seamless integration of WSN with CPS designs are also discussed.
J.-F. Chen et al. propose the pelvic floor muscle training (PFMT) system which is aimed help patients execute their rehabilitation exercises. The proposed PFMT system consists of the PFMT devices, an Arduino control board, a force sensor, a Bluetooth device, and the secure digital memory (SD) card. The embedded force sensor automatically monitors the operations of patients and the Bluetooth device sends timely reports if the PFMT exercise is done incorrectly. By applying the proposed PFMT system, the doctors automatically obtain the behavior in executing pelvic floor muscle training and contact patients for additional visitation(s) if necessary.
Based on CPS technology, creating smart living space becomes an important trend of future development. However, one challenge encountered in establishing a smart living space is that the electronic devices nowadays execute different communication protocols, such as Bluetooth, Zigbee, RF, infrared, among others and even some traditional devices have no communication functions. Z.-Y. Bai and X. Huang design and implement an intelligent control box to convert different wireless signals. The developed intelligent control box can be treated as a multiple control platform which integrates the systems of lighting, air conditioning, access control, video surveillance, alarm, and so on. The proposed intelligent control box provides several control functionalities, including the systems of lighting, air conditioning, access control, video surveillance, alarm, and so on. The proposed intelligent control box automatically converts different wireless signals and removes the difficulties in establishing smart living space with CPS technology.
M. B. Shah et al. propose a context-aware routing protocol for multisink Cell-Phone-based sensor networks (CPSNs). Since the data delivery to the sink is delay tolerant, this paper exploits the mobility of the cell phone (human mobility) to opportunistically forward data to the sink. This approach can be especially applied to the CPSN which is characterized by volatile topology, limited buffer space, and loose connectivity with neighboring nodes. The authors propose a human mobility sensor context aware routing (HMSCAR) protocol-based on human mobility patterns aimed at predicting the best relays for successfully forwarding data to the sinks.
Chalermek Intanagonwiwat proposes the declarative resource naming (DRN) framework to simplify the programming of wireless networks of embedded systems (WNESs). The nodes of WNES can be deployed in dynamic and hostile environments even though the operator may not be able to physically reach them. The proposed DRN framework abstracts low-level details in system and network programming, and it provides many good features including programming simplicity, expressiveness, tunability, on-the-fly reprogrammability, and in-network data aggregation for energy savings. The proposed DRN framework has been implemented on two platforms: Smart Message and Maté, to verify that DRN enables programmers to develop energy-efficient applications with the desired flexibility and quality.
We believe that, in all cases, the selected papers are definitely important ones for this special issue on cyber physical systems using sensor technologies. The editors would like to thank all the authors who have submitted their manuscripts for consideration for this issue. We thank all reviewers for their efforts in reviewing all submitted papers which greatly helped us select the finest papers for this issue.