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Pedestrian dead reckoning (PDR) is a potential technique for smartphone-based indoor localization using the built-in accelerometers and gyroscopes. However, most current PDR positioning approaches restrict the pose to carry a phone, such as holding it in front of the body during tracking. In addition, heading determination is the primary error sources in PDR systems, and hence, a magnetometer is normally required to reduce heading errors. However, in indoor environments, magnetometer outputs would be seriously distorted by magnetic disturbances from the building structures and electronics. In this paper, an experimental heuristic approach to multi-pose PDR (mpPDR) indoor positioning for structured environments has been proposed. Six poses and four modes to carry a phone could be recognized, and then, on the basis of different modes, an experimental approach to the heading determination without using magnetometers has been presented to reduce the heading error considering the effects of turning and hand-shaking events. The experimental results indicate that the proposed approach supports four smartphone modes with a high position accuracy of 97.99%.

With economic development and changes in the industrial environment in the world, it is necessary to build an automated production line in the modern factory. Because of the excellent functions and high stability of the programmable logic controller (PLC), it is mainly used to integrated control systems to control devices. e.g., sensors, servo motors, and pressure systems. This paper combines PLC, mobile App, and Arduino modules to create a fully automated agricultural technology.

With the rapid development of industrial technologies, a lot of wastes have been produced in modern life. In order to efficiently recycle the wastes, this paper has designed and implemented an intelligent recycling bin using the MobileNet-SSD (Single-Shot Detector) networks. Experimental results indicate the feasibility and practicality of the implemented system, in which the accuracy reaches above 90% for the plastic bottles and metal cans.

For discrete automation systems, certain human operations may violate desired safety requirements and result in catastrophic failure. For such humanin-the-loop systems, this paper proposes a systematic approach to developing supervisory agents which guarantee that manual operations meet required safety specifications. In the present approach, Petri nets (PN) are applied to construct a system model and synthesize a desired supervisor. Applications to 1) a rapid thermal process (RTP) in semiconductor manufacturing controlled over the Internet (Lee and Hsu, 2003) and 2) a two-robot remote surveillance system (Lee et al., 2005) are provided to demonstrate the practicability of the developed supervisory control approach. The technique developed in this paper is significant in industrial applications. 1.1 General Review Basically, an automated process is inhe rently a discrete event system (DES). The Petri net (PN) has been developed as a powerful tool for modelling, analysis, simulation, and control of DES. PN was named after Carl A. Petri (1962), who created a net-like mathematical tool for describing relations between the conditions and the events. PN was further developed to meet the need in specifying process synchronization, asynchronous events, concurrent operations, and conflicts or resource sharing for a variety of industrial automated systems at the discrete-event level. Starting in the late of 1970’s, researchers investigated possible industrial applications of PN in discrete-event systems as in the survey/tutorial papers of Murata (1989), Zurawski and Zhou (1994), David and Alla (1994), and Zhou and Jeng (1998).

Energy conservation plays a crucial role in sensor network design. Hierarchical clustering design is one of the approaches to save energy of the sensor networks. However, for mobile sensor networks (MSNs), packet loss that occurs due to the mobility of sensor nodes is also an important issue. In this paper, an improved low-energy adaptive clustering hierarchy protocol for MSNs has been proposed to not only prolong the network lifetime, but also reduce the packet loss using fuzzy inference systems. Simulation results indicate that the proposed approach is more effective than the other existing ones in terms of the network lifetime, energy consumption, packet delivery ratio, and cluster deviation. Therefore, the technique presented in this paper could further be adapted to investigate highly MSNs.

The Internet of Things is being established nowadays, and the deployment of devices to be interconnected with each other and to the Internet is becoming a more common issue. The Internet of Things is structured in several levels and, in this regard, depending on the layer in which these devices are located, the complexity range and specific constraints arise. In the lowest level of this structure, the so-called edge is found, where the data are gathered from the environment by tiny electronic devices which are very limited in energy, computing, and memory resources. These devices, in turn, present different levels of complexity, which lead to a distinction between the edge layer and the sensor or extreme edge layer. In the extreme edge is where the most essential and limited tasks are carried out, these are sensing and sending data. Meanwhile on the edge, in addition to sensing, some processing can be performed in order to offload upper layers and to save precious energy by not communicating useless data. In this review paper, the structure of the Internet of Things is presented and the extreme edge is detailed, presenting the implementation options and requirements, with the purpose of having a better understanding of the needs when a specific application has to be developed and a set of devices has to be deployed. A special emphasis receives the bottom layer, focusing on devices oriented to last unattended for tens of years.

In recent years, energy conservation has become a critical issue. Residential lighting consumes a surprisingly large share of the electricity. In this paper, a residential lighting control system using ZigBee wireless technology has been proposed. In the present scheme, the ZigBee localization technique is integrated into the lighting control system so as to reduce the power consumption. The experimental results demonstrate the feasibility of the proposed approach that could save the energy around 11.81%.

ZigBee is an emerging standard specifically designed for wireless personal area networks (WPANs) with a focus on enabling the wireless sensor networks (WSNs). It attempts to provide a low-data rate, low-power, and low-cost wireless networking on the device-level communication. In this paper, we have established a realistic indoor environment for the performance evaluation of a 51-node ZigBee wireless network. Several sets of practical experiments have been conducted to study its various features, including the (1) node connectivity, (2) packet loss rate, and (3) transmission throughput. The results show that our developed ZigBee platforms could work well under multihop transmission over an extended period of time.

This paper presents a preliminary development of the smart shopping cart (SSC) that can be integrated into the smart mall system. The SSC can provide customers with the efficient user interface so that the shopping service can be effectively promoted. In the current design, with the function of face recognition on the user interface, the SSC can recognize the customer and further provide the associated assistive shopping information based on the purchase history. With the use of radio-frequency identification (RFID) tags, the SSC can automatically detect the various products which are being added in the cart and show the related information on the user interface. Through the searching function of SSC, the purchasing efficiency and navigation aid in the mall can be effectively supplied. Finally, the automatic billing service can be done by the SSC and the stored shopping data will be transmitted to the cloud server of shopping mall. The experimental demonstration shows the effectiveness of the proposed SSC which interacts with the customer and provides efficient shopping service.

Control design plays a key role in electric-assist bikes. This paper has established dynamic models of electrically assisted biking systems, and then, designed proportion-assisted power controllers (PAPC) in accordance with Taiwan government rules. In the PAPC controllers, current bike speed and pedal torque are used as inputs to determine the assisted torque generated from a motor. On the other hand, a fuzzy logic controller (FLC) has been also designed, using the current bike speed and pedal frequency as inputs to determine the assisted torque. In order to compare these two controllers, simulations of riding bikes on a flat ground and different slopes have been performed. Simulation results show that the FLC outperforms PAPC in a more stable bike speed.

This paper was motivated by the requirement of remote coordination for flexible manufacturing systems (FMS), in which certain requested commands may lead to undesired states. For such discrete event systems (DES), this paper applies a command filtering scheme for modeling and synthesis of filters using Petri nets so as to guarantee that the closed coordinated manufacturing system satisfies the requirements. Moreover, a systematic algorithm for the design and integration of modular command filters is proposed in order to cope with the complexity and realization issues in large-scale FMS. To show the practicability of the developed method, an application to an FMS with three product types is provided. The proposed approach contributes a promising tool for preventing undesirable actions from occurring in FMS which may be also applied to other types of DES if appropriately modified.

In semiautonomous mobile sensor networks (MSNs), since human operators may be involved in the control loop, particular improper actions may cause accidents and result in catastrophes. For such systems, this paper proposes a command filtering framework to accept or reject the human-issued commands so that undesirable executions are never performed. In the present approach, Petri nets are used to model the operated behaviors and to synthesize the command filters for supervision. An application to a mobile wireless surveillance system is provided to show the feasibility of the developed approach. It is believed that the technique presented in this paper could be further applied to large-scale wireless MSNs.

In a semiconductor manufacturing system, particular human operations may violate desired requirements and lead to destructive failure. For such human-in-the-loop systems, this paper proposes a supervisory framework which guarantees that manual operations meet required specifications so as to prevent human errors in operation using Petri nets. Moreover, a modular technique with an intersection mechanism is proposed in order to cope with the state-space explosion problem of large-scale systems. A rapid thermal process in semiconductor manufacturing systems is provided to show the practicability of the proposed approach. Note to Practitioners - This work was motivated by the requirement of remote monitoring and supervision of semiconductor manufacturing systems. In such human-in-the-loop and large-scale systems, certain human operations may violate desired safety requirements and result in catastrophic failure. Moreover, the overall complexity of most existing Petri net modeling and analysis approaches significantly increases with the size of the considered systems. This paper suggests a modular supervisory scheme for modeling and synthesis of supervisory agents using Petri nets. The proposed method contributes a promising tool for preventing abnormal operations from being carried out to semiconductor manufacturing systems which, if appropriately modified, may be also applied to other types of discrete event systems.

For remote control systems, certain human operations may violate desired requirements and result in catastrophic failure. For such human-in-the-loop systems, this paper implements a hierarchical supervision system to guarantee that remote human-issued commands meet required specifications. In the presented scheme, Petri nets are applied to model, design, and verify both the local controller and the remote supervisor. Then, the agent technology is adopted to implement the supervisor as an intelligent agent for an online supervision of the remote control system. Hence, undesired resource conflicts and deadlock states can be avoided. An application to a flexible manufacturing system controlled over the Internet is provided to illustrate the developed approach. Implementation results show that by applying the presented hierarchical scheme, the supervisor has a more compact model with fewer states. Moreover, fewer request/response transmissions are consumed so that the effects of time delays and packet losses across the Internet could be moderated

In a distributed robotic system, both human-controlled (semi-autonomous) and computer-controlled (fully autonomous) robots may simultaneously exist. From the global system's point of view, supervisory control for the interactions between the human and computer are important and necessary. For such human-computer interactive systems, this paper proposes a supervisory framework to guarantee that both human and computer commands meet collision-free and deadlock-free requirements. In the presented approach, Petri nets are applied to construct a system model and synthesize a desired supervisor. An application to a two-robot remote surveillance system is provided to demonstrate the practicability of the developed supervisory control approach. It is believed that the technique developed in this paper is significant in the industrial practice.

This paper presents a systematic approach for the design and implementation of the sequence controller in manufacturing systems. By employing the IDEF0, we construct the simplified Petri net controller (SPNC) through the material flow diagram and the information flow diagram. Then, the ladder logic diagram (LLD) can be transformed from the SPNC through the token passing logic (TPL). The proposed approach, including the IDEF0, SPNC, and TPL tools, leads to the standard IEC1131-3 LLD for PLC implementation. Finally, an application of a stamping process is provided to illustrate the design procedure of the developed approach .

For large-scale and long-distance distributed systems, this paper proposes a systematical multiparadigm approach to develop the simple network management protocol (SNMP) agents for remote monitoring and control. The standard unified modeling language (UML) is adopted for modeling the system, and then the Petri-net model is applied to achieve both qualitative and quantitative analyses for the system's dynamic behavior. In real applications, the present design can be further implemented with Java and ladder diagrams on programmable logic controllers (PLC). The developed system has been used successfully in a mobile switching center (MSC) of Taiwan Cellular Corporation for the remote monitoring and control, through the Internet, of its environmental conditions, including the temperature, humidity, power, and security, with a total of 316 sensors and 140 actuators.

Due to the rapid development of the Internet, research on networked control system (NCS) has attracted much attention. However, when the control is over the network, the communication time delay will reduce the stability and performance of the entire system. This paper presents a comparative study of time delay compensation methods based on a communication disturbance observer (CDOB) architecture. Also, applications of fuzzy control theory and neural network modeling to the CDOB are presented. Simulation results show that the presented approach can be effectively applied to the NCS with time delays.

Modeling and control plays an important role in the automated manufacturing applications. Remote operation provides the capability to perform monitoring and control over a great distance. In this paper, behavior modeling and remote control of an industrial conveyor system has been presented. In the present approach, colored Petri nets (CPNs) are used to model the operated behaviors so as to result in a more compact structure. A prototype of a seven-position conveyor system is designed and implemented to show the feasibility of the developed approach. It is believed that the technique presented in this paper could be further applied to large-scale industrial conveyor systems.

For Internet applications, e.g., video streaming and file download, bandwidth and end-to-end propagation delay are two significant parameters that affect quality of service. The merit of Client-Server data transmission is able to reduce unnecessary end-to-end propagation delay, but additional upload bandwidth is required at the server (original source) side. However, in peer-to-peer (P2P) data transmission, less upload bandwidth is required, but longer end-to-end propagation delay might be resulted due to complicated network topology. In this paper, we will design hybrid P2P Client-Server data transmission (denoted as HPCS), in which the original source is able to determine the method of data transmission for each connected peer, and further separate connected peers into P2P and Client-Server groups. In our experiments, the number of connected peers and proper upload bandwidth can be determined for P2P and Client-Server groups based on end-to-end propagation delay, upload bandwidth and system loading, and thus a traded-off performance can be achieved.

ZigBee is an emerging standard specifically designed for low-rate wireless personal area networks (LR-WPAN) with a focus on enabling the wireless sensor networks. It attempts to provide a low data rate, low power, and low cost wireless networking on the device-level communication. In this paper, we have established a realistic environment for the performance evaluation of the ZigBee wireless networks. Several sets of practical experiments are conducted to study its various features, including the 1) packet loss rate, and 2) transmission throughput. The results show that our developed ZigBee platforms could work well under multi-hop transmission over a long period of time.

In wireless sensor networks (WSN), a binding is an association between a sensor and an actuator. The binding mechanism defined in the ZigBee specification is restricted within a personal area network (PAN). For a complex WSN application, it is desired to have an inter-PAN binding mechanism to combine sensors and actuators from different PANs, respectively. In this paper, we have proposed a gateway-based inter-PAN binding mechanism for global event detection and action invocation. By collecting device capabilities from each intra-PAN gateway, an inter-PAN gateway is used to create a binding specification. Once all events defined in the binding specification are received from related intra-PAN gateways, the inter-PAN gateway would initiate corresponding actions on all associated intra-PAN gateways. To demonstrate the practicality, an inter-PAN binding system for ZigBee sensors and actuators has been implemented based on the universal plug and play (UPnP) and representational state transfer (REST) Web services for intra-PAN gateway discovery and device capability collection. Also, a Web-based wizard has been provided to create binding specification. It is believed that the technique presented in this paper would enable the interaction between ZigBee PANs to perform wide-ranging WSN applications.

For complicated pharmaceutical manufacturing processes, using real devices for system integration and testing not only increases the cost but also takes a longer time. In this paper, a systematic approach to the model construction for system integration in pharmaceutical manufacturing processes is proposed. In the present approach, the integration definition language zero (IDEF0) for function modeling and Petri net (PN) are applied to perform the functional and behavior analyses of the processes, and a verified PN model can be then obtained for the implementation of system integration. An application of a monomer synthesis process in pharmaceutical manufacturing systems is provided to illustrate the design procedure of the developed approach.

ZigBee standard is a low-complexity and energy-efficient wireless protocol for sensor network applications. It has been promoted by ZigBee alliance and widely developed by many companies for a variety of applications. In this paper, we introduce the residential mode of security mechanism in ZigBee networks for smart home networking applications, and we then point out the security problems when using this mode. Specifically, we show that the ZigBee network is subject to replay attacks, and thus packets information could be revealed to attackers. Moreover, the encryption keys are also possible to be revealed during the key update operation within ZigBee networks. To overcome the latter issues, in this paper, we provide some recommendations to improve the security of ZigBee sensor networks for residential applications. It is believed that the suggestions presented in this paper would benefit application engineers in designing the sensor networking security.

In remotely operated weapon systems (ROWS), since the human soldier is involved in the control loop, particular improper operations may cause accidents and result in catastrophes. For such systems, this paper has used a command-filter-based framework to accept or reject the human-issued commands so that undesirable executions would never be performed. In the present approach, Petri nets (PN) are used to model the operated behaviors and to synthesize the command filter for supervision. An application to missile loading and launching processes is provided to show the feasibility of the developed approach. It is believed that the technique presented in this paper could be further applied to large-scale military weapon systems.

For the improvement of the reliability and safety of industrial processes, a fault detection and tracing approach has been proposed. In this paper, the P-invariant of Petri Nets (PN) is applied to discover sequence faults, while both sensor faults and actuator faults are detected using exclusive logic functions. For industrial applications, the proposed fault detector has been implemented within a programmable logic controller (PLC) by converting the fault detection logic functions into ladder logic diagrams (LLD). Moreover, a fault tracer has been modeled by an AND/OR tree and a tracing procedure is provided to locate the faults. A mark stamping process is demonstrated as an example to illustrate the proposed diagnostic approach.

Bluetooth, ultra-wideband (UWB), ZigBee, and Wi-Fi are four popular wireless standards for short-range communications. Specifically, ZigBee network is an emerging technology designed for low cost, low power consumption and low-rate wireless personal area networks (LR-WPAN) with a focus on the device-level communication for enabling the wireless sensor networks. In this paper, after a brief overview of the four short-range wireless standards, the developed ZigBee platforms, ITRI ZBnode, have been presented for wireless sensor networking applications. Moreover, design issues for ZigBee industrial applications and the experimental implementation have been demonstrated via a multi-hop tree network.

Inside a wireless sensor network comprising both static sensors and mobile robots, as human commands are issued within the control loop, particular improper actions may cause accidents and result in disasters. For such systems, this paper has proposed a command filtering framework to accept or reject the human-issued commands so that undesirable executions are never performed. In the present approach, Petri nets (PN) are used to model the operated behaviors and to synthesize the command filters for supervision. An application to a mobile wireless surveillance system is provided to show the practicability of the developed approach. It is believed that the technique presented in this paper could be further applied to large-scale wireless mobile sensor networks.

Bluetooth (over IEEE 802.15.1), ultra-wideband (UWB, over IEEE 802.15.3), ZigBee (over IEEE 802.15.4), and Wi-Fi (over IEEE 802.11) are four protocol standards for short- range wireless communications with low power consumption. From an application point of view, bluetooth is intended for a cordless mouse, keyboard, and hands-free headset, UWB is oriented to high-bandwidth multimedia links, ZigBee is designed for reliable wirelessly networked monitoring and control networks, while Wi-Fi is directed at computer-to-computer connections as an extension or substitution of cabled networks. In this paper, we provide a study of these popular wireless communication standards, evaluating their main features and behaviors in terms of various metrics, including the transmission time, data coding efficiency, complexity, and power consumption. It is believed that the comparison presented in this paper would benefit application engineers in selecting an appropriate protocol.

Research of the past years has led to numerous novel developments and approaches for wireless sensor networks (WSNs). However, most previous work has focused on either mathematical analysis or theoretical algorithms with extensive simulation results. In this paper, in order to realistically understand the complexity of WSNs, a ZigBee/IEEE 802.15.4 platform has been designed and implemented. Based on an IEEE 802.15.4 radio and ZigBee protocol stack, the developed ITRI ZBnode is an autonomous wireless communication and computing platform aimed at fast prototyping and research in WSNs. The platform attempts to provide a low data rate, low power, and low cost wireless networking on the device-level communication. Finally, examples of tree and mesh network formation are provided to demonstrate practicability of the developed ZBnode platform.

IEEE 802.15.4 is an emerging standard specifically designed for low-rate wireless personal area networks (LR-WPAN) with a focus on enabling the wireless sensor networks. It attempts to provide a low data rate, low power, and low cost wireless networking on the device-level communication. In this paper, we have established a realistic environment for the preliminary performance evaluation of the IEEE 802.15.4 wireless networks. Several sets of practical experiments are conducted to study its various features, including the effects of I) the direct and indirect data transmissions, 2) CSMA-CA mechanism, 3) data payload size, and 4) beacon-enabled mode. The data throughput, delivery ratio, and received signal strength indication (RSSI) are investigated as the performance metrics

Sequence controller designs play a key role in advanced manufacturing systems. Traditionally, the ladder logic diagram (LLD) has been widely applied to programmable logic controllers (PLC), while recently the Petri net (PN) has emerged as an alternative tool for the sequence control of complex systems. The evaluation of both approaches has become crucial and has thus attracted attention. The “basic element” approach was developed to evaluate the complexity and flexibility for LLD and PN design approaches [1, 2, 3, 4]. However, the basic elements of these two designs are inherently different and hence that approach may lead to unreliable results. Since sequence control here naturally implies the use of logic rules, a rule-based approach is proposed in this paper to provide unified measures for both LLD and PN designs. To illustrate the proposed approach, it is applied to five control sequences with increasing complexity for a stamping process. Results indicate that the proposed approach is more suitable for real applications and, furthermore, PN is increasingly superior to LLD as the control sequence becomes more complex.

For complex and large-scale semiconductor manufacturing systems, using real devices for system integration and testing not only increases the cost but also takes a longer time. In this paper, a systematic approach for the emulator design of the manufacturing equipment to achieve system integration is proposed. In the proposed approach, the integration definition language 0 (IDEF0) and Petri net (PN) are applied to perform the functional and behavior analyses of the equipment, and then a verified PN model can be obtained for the implementation of emulators. An application of a rapid thermal process (RTP) in semiconductor manufacturing systems is provided to illustrate the design procedure of the developed approach.

For remote-controlled multi-recipe processes, certain issued commands may lead to undesired resource conflicts and deadlock states. Moreover, as a result of the communication delay and packet loss in the Internet, remote control of a group of certain steps are recommended rather than control of each step. For these Web-based control systems, this paper proposes a three-level architecture for hierarchical supervision. In the upper supervisory level, the supervisory agent guarantees that issued commands from the remote manager, in the middle command level, satisfy the resource sharing and deadlock-free requirements when executing a number of concurrent recipes, while the local controller, in the lower control level, performs the corresponding detailed operations to meet the requested tasks. In the present approach, Petri nets (PNs) are used to model, design, and verify the supervisory agent and local controller, and then, Java technology and ladder logic diagrams (LLDs) are adopted for implementation to achieve online supervision of the remote-controlled processes. To demonstrate the practicability of the developed supervisory approach, we apply it to a three-recipe flexible manufacturing system (FMS) controlled over the Internet.

The fast Fourier transform (FFT) is applied to the sampled boundary distances (SBD) of an object image for recognition. The SBD is an ordered collection of samples of distances defined from an axis to points located on the boundary of the object image. With the FFTSBD approach, any object image that undergoes affine transformations such as translation, rotation, scaling, and stretching (along and/or perpendicular to the stretching axis) can be recognized. Therefore, the FFTSBD can be used to recognize an object at various locations, orientations, and distances from the camera and various objects of the same family that are stretched along an axis. FFTSBD can also be used to recognize heavily occluded objects, provided that the endpoints of the major axis are visible, and to recognize family of objects stretching along an axis, provided that the endpoints of that axis are visible. SBD can be used to extract axis of symmetry and to detect symmetry from a partially occluded object provided that the endpoints of major axis and axis of symmetry are not occluded. >

Recently, methods have been proposed for obtaining the ladder logic diagram (LLD) based on the Petri net (PN). However, those resulting LLD are usually not in compact forms. Moreover, forming the PN structures to model manufacturing processes is not straightforward. In this paper, we propose a simplified Petri net controller (SPNC) by introducing sensor states into the PN. A compact LLD can be then obtained through the token passing logic (TPL). By employing the integration definition language 0 (IDEF0) technique, we obtain the SPNC structure sequentially through material flow diagrams and information flow diagrams. The result of an integrated IPTL (IDEF0/SPNC/TPL/LLD) algorithm, including the IDEF0, SPNC, and TPL tools, leads to the standard IEC1131-3 LLD for PLC implementation. An example of a mark stamping system is provided to illustrate the developed design approach.

Recently, designs for the automated highway systems (AHS) to improve the safety and efficiency of highways have attracted much attention. However, such large-scale and complex dynamic systems present a number of control issues. Part of the complication comes from the hybrid nature of these systems, which consists of both time-driven and event-driven dynamics. In this paper, an object-oriented representation towards a hybrid controller design for automated vehicles in an AHS is proposed. The traditional discrete statechart of unified modelling language is extended to model the continuous dynamics of hybrid controllers in a hierarchical and natural representation. The proposed modelling approach provides a clear and natural representation of the interaction between the discrete and continuous behaviours.(A)