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In this numerical work, a Mach–Zehnder interferometer device with sample and reference arms composed of microstructured chalcogenide optical fibres with AsSe2 core and As2S5 cladding is presented to generate single and double pulses. An unchirped hyperbolic secant-shaped pulse with enough high peak power centered at 1958 nm wavelength and a continuous wave with a very weak power level at 2070 nm wavelength are simultaneously introduced into the sample arm, in which stimulated Raman scattering and strong cross-phase modulation induced by two co-propagating waves give rise to a significant phase shift for a continuous wave. In the reference arm, the continuous wave directly passes through the fibre, where the transmitted wave has a slight phase shift due to the influence of self-phase modulation. Therefore, at the output port of the configuration, the re-combined optical fields at 2070 nm wavelength have a significant phase difference. As a result, both single and double pulses caused by the optical interference at the output port are achieved by judiciously adjusting the phase difference which is mainly controlled by the peak power and temporal width of the input optical pulse, as well as the length of a microstructured optical fibre. In addition, both widths of the single pulse and spacing of the double pulses are directly dependent on the temporal width of the input pulse and the fibre length of the arm.

We evaluate a Bluetooth-based mobile contact-confirming app, COVID-19 Contact-Confirming Application (COCOA), which is being used in Japan to contain the spread of COVID-19, the disease caused by the novel virus termed SARS-COV-2. The app prioritizes the protection of users’ privacy from a variety of parties (eg, other users, potential attackers, and public authorities), enhances the capacity to balance the current load of excessive pressure on health care systems (eg, local triage of exposure risk and reduction of in-person hospital visits), increases the speed of responses to the pandemic (eg, automated recording of close contact based on proximity), and reduces operation errors and population mobility. The peer-to-peer framework of COCOA is intended to provide the public with dynamic and credible updates on the COVID-19 pandemic without sacrificing the privacy of their information. However, cautions must be exercised to address critical concerns, such as the rate of participation and delays in data sharing. The results of a simulation imply that the participation rate in Japan needs to be close 90% to effectively control the spread of COVID-19.

Indoor positioning systems based on wireless local area networks are growing rapidly in importance and gaining commercial interest. Pedestrian dead reckoning (PDR) systems, which rely on inertial sensors, such as accelerometers, gyroscopes, or even magnetometers to estimate users' movement, have also been widely adopted for real-time indoor pedestrian location tracking. Since both kinds of systems have their own advantages and disadvantages, a maximum likelihood-based fusion algorithm that integrates a typical Wi-Fi indoor positioning system with a PDR system is proposed in this paper. The strength of the PDR system should eliminate the weakness of the Wi-Fi positioning system and vice versa. The intelligent fusion algorithm can retrieve the initial user location and moving direction information without requiring any user intervention. Experimental results show that the proposed positioning system has better positioning accuracy than the PDR system or Wi-Fi positioning system alone.

Building context-aware services in pervasive computing environments have enabled the wide development of wireless local area network-based indoor positioning systems. In fingerprint localization, radio frequency (RF) signal strengths from access points (APs) are annotated with location labels to build the map of RF fingerprints. However, the newly received signal strength (RSS) variation due to device heterogeneity, which may cause RSS pattern mismatch, could jeopardize positioning accuracy. Solutions based on extra manual calibrations of RSSs for new, individual devices could address the problem. However, they are laborious and unpractical for real-world deployment. In this paper, an indoor positioning algorithm that utilizes two homogeneous features of different devices is proposed to solve the problem of device heterogeneity in fingerprint localization. The features of RSS order and linear dependency between RSSs measured by different devices are extensively investigated. The experimental results show that the proposed positioning algorithm solves the device heterogeneity problem without requiring extra manual calibration for diverse devices.

Nowadays, Intelligent Transportation Systems (ITS) technologies are exploring a wide range of services such as freeway management, crash prevention & safety, driver assistance, and infotainment of drivers and/or passengers. In this paper, an agile urban parking recommendation service for vehicular intelligent guiding system is designed to facilitate city citizens with fully efficient, real-time and precise parking lot guiding suggestions for the sustainability of the future green city. The system offers drivers a friendly parking lot recommendation sequence and saves driver's time circling around by the accurate prediction of the successful parking probability in each parking lot. The proposed cost model constructs an optimal recommendation sequence considering successful parking probability and time to reach the parking lot. Through the collection and analysis of realistic records from parking lots in Taipei city, a prediction algorithm is developed to estimate the successful parking probability by using current available space counts. Extensive experiments are conducted to demonstrate the effectiveness of the prediction algorithm.

Driven by the growing number of the mobile subscribers, efficient channel resource management plays a key role for provisioning multimedia service in the next generation personal communication systems. To reuse limited channel resources, diminishing the coverage areas of cells seems to be the ultimate solution. Thus, however, causes more handover events. To provide seamless connection environment for mobile terminals and applications, this article presents a novel handover scheme called the intelligent channel reservation (ICR) scheme, which exploits the location prediction technologies to accurately reserve channel resources for handover connections. Considering the fact that each mobile terminal has its individual mobility characteristic, the ICR scheme utilizes a channel reserving notification procedure (CRNP) to collect adequate parameters for predicting the future location of individual mobile terminals. These parameters will be utilized by the handover prediction function to estimate the expected handover blocking rate and the expected number of idle channels. Based on the handover prediction estimations, a cost function for calculating the damages from blocking the handover connections and idling channel resources, and a corresponding algorithm for minimizing the cost function are proposed. In addition, a guard channel decision maker (GCDM) determines the appropriate number of guard channels. The experimental results show that the ICR scheme does reduce the handover-blocking rate while keeping the number of idle channels small.

In recent years, several kinds of wireless network have been widely deployed. In this work, we focus on the e-bus-system for movements of buses. Passengers can get the bus information through the intelligent bus stop when they are waiting for the bus. In today’s environment of Taiwan, the transportation information is provided through some specific Mobile network operators. In this case, it costs a huge expenditure every month for the charge of data transmission. Therefore, we propose a new network system with Digital Mobile Radio (DMR) and Super Wi-Fi to replace the mobile network operator. Furthermore, when the catastrophe happened, the proposed system can also change to be used for the rescues. The implementation of the system architecture, the application of DMR and super WiFi in the proposed system, and the operation scenario are described in this paper.

EIMS is a stable and safe communication system. It integrates the communication of citizen patrols and police units. When unexpected emergency happens, the system can enhance the citizen patrols' communications capabilities, decrease the time in communication and response, and reduce the loss of life and property. There are five citizen patrols implemented EIMS in northern Taiwan. They have enhanced the capacity of community citizen patrols. And, there are more than 1,500 residents to enjoy the efficient of its system.

The fingerprint-based techniques are commonly used for indoor location estimation, in which a radio map is built by calibrating signal-strength values at several training locations in the offline phase. However, the signal-strength values change as the environment changes, and hence the radio map built may be out of date. Further, the recalibration of signal-strength values for each environment change is laborious and time consuming. Therefore, in this paper, an efficient radio map management method is proposed in response to the environment changes. We first demonstrate that different features of signal propagation are obtained in different regions of the indoor environment. According to the different features of signal propagation, the environment is divided into several regions and the signal-strength values collected at the training locations in different regions can be updated accurately and individually using proper propagation features. The experimental results show the usefulness of the proposed method and the accuracy of the localization can be improved.

Severe received signal strength (RSS) fluctuation is one of the crucial problems in an indoor positioning system using fingerprint-based algorithms. Even at a fixed location, the RSSs received by a mobile device at different time have large discrepancy. Adopting these fluctuated signals for positioning may lead to inaccurate results. To mitigate this problem, in this paper, any of the existing fingerprint-based indoor positioning algorithms can be integrated into our positioning system to estimate the location of mobile device. Then, a mobility prediction algorithm using the model of Brownian motion is presented for further calculating the rationality of the estimated location and correcting the inaccurate results. To be realistic, some experiments in a real WLAN environment with a multitude of people moving in a testing area demonstrate the noticeably better accuracy of this approach. The solution can ensure low and stable positioning error. Besides, the region where training records are out of date can also be found out.

This paper presents a new behavior classification system that can analyze human behaviors from arbitrary views. Technically, if different viewing angle are used for observing a person, his appearances will change significantly. To freely recognize his behaviors, traditional methods tend to adopt 3-D data for behavior analysis. However, its inherent correspondence process will make it inappropriate for real time applications. To tackle this problem, a novel view alignment method is first proposed for mapping each action sequence to a fixed view. To achieve this mapping, two features extracted from spatial and temporal domains are used for representing each action sequence. For the spatial feature, the "centroid context" of each posture is defined and extracted through a triangulation technique. For the temporal feature, the "posture transition probability" is constructed for recording the probabilities of one posture type transferring to another one. After mapping, a novel matrix representation is proposed for describing each action more accurately. After that, the Viterbi algorithm is used for aligning two action sequences and then classifying them to different behavior types.

In recent years, rapid growth of the Internet and Instant Messaging (IM) technology makes IM a popular communication tool. In the meantime, Internet trend is evolving into the new generation, Web2.0, with emphasis on user co-constructing cybercontents. People around the world communicate with each other via on-line IM all day long. If you are stuck in an unfamiliar place and need assistance, asking assistance through IM service is a warrant that support will be delivered to you in time. Therefore, we propose to combine Google Talk (GTalk) of handheld devices with IM service over Web 2.0 forming a support system to assistance tourist travel in unfamiliar areas with confidence. When you need assistance, the content of your question message is input into a speech server by constructing an analytical model for Speech Interface Languages (SILs) system. The speech server translates your speech into text and sent out to IM Web 2.0 group for answering. Later on, when you log in the GTalk again, assistance will come to your hand at once. Because so many people are using on-line IM for 24 hours, the system should be very helpful for tourist around the world. Our system is now going on feasibility study and a large scale of experiment will conduct when we collect enough response about the system.

This study proposed a smart control algorithm to naturally adjust the thermal quality of the environment according to the interior and exterior environmental factors and the behavior of the inhabitants. To design an appropriate smart control algorithm for the smart buildings in the subtropical zones, this study conscientiously investigated the thermal effect of smart-skin facades of some office buildings in Taiwan to learn the correlation of the thermal parameters and the requirements of the inhabitants. To evaluate and further improve the proposed algorithm, an experimental building with two experimental zones was constructed. The experimental results show that the proposed algorithm significantly improves the thermal comfort and reduce power consumption through well coordinating the smart-skin equipment and air conditioners.

This paper presents a 802.11-based positioning system developed and demonstrated in the Taipei Children's Museum of Transportation and Communication. Our positioning system partitions the service area into several regions and signal strength information which contains a sequence of access point IDs with the average power strength measured in the region will be collect. Our positioning system locates mobile users via collecting power strengths of the mobile users and then applies our algorithm to determine the regions in which the mobile users stay. A location database is applied to maintain the signal strength information. The experimental results validate that the location information provided by our positioning system assures high correctness of region classification.

Nowadays, medical centers are working on setting a safe medicating environment by using information technology. This study tried to improve patients' safety environment, communications among medical workers and patients, medicating quality, and medical process efficiency through a wireless handheld RFID patient safety enhancement system for medical personnel. The proposed portable patient information integration system combines Radio Frequency Identification (RFID) technology, Wireless Network, Personal Digital Assistant (PDA) and Front-Monitoring System. Through the help of the proposed system, the medical workers can identify patients by non contact identification and get medical record immediately. Meanwhile the proposed system can record the history of the interaction between medical personnel and patients. It can also send alarm to the corresponding medical workers when reporting a high risk testing result and give medicine safety suggestion. The proposed system can improve the correctness and instantaneousness of patients' medical information and hence provide a safe environment for patients, and the Wan Fang Hospital is now verifying the performance of this system for improving the patients'safety.

This paper presents a smart home system prototype which employs an indoor positioning system called the Best Beacon Match (BBM) positioning method to intelligently trigger the appropriately services for the home members. To overcome the ninja problem in the BBM method, the signal filtering, adjustment and smooth procedures are proposed. We employ the Zigbee module to implement the prototypes of the components for the BBM positioning method, and the prototypes were pass the ZigBee Compliant Platform (ZCP) certification test. The proposed system prototype which intelligently controls the air condition and light system for smart home applications is also verifying in our demo room and in the smart house in National Taiwan University.

Emergency medicine is an important link in healthcare system. There is high complexity about the medical process across with different organizations because the care operation including multiple procedures and it's hard to pre-scheduling when there are many random emergencies happened in the chaotic environment. The bottleneck of emergency medicine system is hard to integrate the virtual data and physical object in emergency medical service (EMS) in real time with limited resource. The research describes an empirical experience about how Wan-Fang hospital in Taiwan implements RFID technology in EMS at the first stage, and how we integrate with the existent EMS architecture and legacy system. We develop an RFID EMS system, and evaluate the benefit from the implementation by quantity and quality methodology. The research can be referred to practice and academic in medical informatics related fields.

The attempts to develop a ubiquitous health care monitoring system arisen from the need of automatic real-time medical services for emergent diseases. Besides, the physiological statuses gathered and maintained by this system are very helpful for diagnosis and early warning. To improve the medical services and diagnosis accuracy, a Wireless Health Advanced Mobile Bio-diagnostic System (abbreviated as WHAM-BioS) is proposed. This study focuses on network/communication technology in the WHAM-BioS and proposes a novel clustered sensor network (CSN) architecture for long-term periodical telecare applications. In the proposed CSN architecture, most network functions are concentrated in a special purpose device called the human body gateway (HBG). The sensor nodes focus on detecting and reporting their detection results to their HBG. To reduce the design complexity and the implementation cost for the sensor nodes, the proposed architecture proposed several protocols to help each HBG to provide a contention free environment for their sensor nodes. The contention free environment significantly reduces the power consumption in data retransmission. Besides, to further reduce the power consumption of the sensor nodes, this study also proposes a power saving mechanism, which reduces the power consumption in idle listening. Based on the proposed network architecture and protocols, a prototype system is implemented

A newly developed smart sensor node that can monitor the safety of temporary structures such as scaffolds at construction sites is detailed in this paper. The design methodology and its trade-offs, as well as its influence on the optimization of sensor networks, is examined. The potential impact on civil engineering construction sites, environmental and natural disaster pre-warning issues, etc., all of which are foundations of smart sensor nodes and corresponding smart sensor networks, is also presented. To minimize the power requirements in order to achieve a true wireless system both in terms of signal and power, a sensor node was designed by adopting an 8051-based micro-controller, an ISM band RF transceiver, and an auto-balanced strain gage signal conditioner. With the built-in RF transceiver, all measurement data can be transmitted to a local control center for data integrity, security, central monitoring, and full-scale analysis. As a battery is the only well-established power source and there is a strong desire to eliminate the need to install bulky power lines, this system designed includes a battery-powered core with optimal power efficiency. To further extend the service life of the built-in power source, a power control algorithm has been embedded in the microcontroller of each sensor node. The entire system has been verified by experimental tests on full-scale scaffold monitoring. The results show that this system provides a practical method to monitor the structure safety in real time and possesses the potential of reducing maintenance costs significantly. The design of the sensor node, central control station, and the integration of several kinds of wireless communication protocol, all of which are successfully integrated to demonstrate the capabilities of this newly developed system, are detailed. Potential impact to the network topology is briefly examined as well.

Most wireless sensor networks base their design on an ad hoc (multi-hop) network technology that focus on organizing and maintaining a network formed by a group of moving objects with a communication device in an area with no fixed base stations or access points. Although ad hoc network technologies are capable of constructing a sensor network, the design and implementation of sensor networks for monitoring stationary nodes such as construction sites and nature-disaster-prone areas can be furthered simplified to reduce power consumption and overhead. Based on the nature of immobile nodes, a hierarchical sensor network architecture and its associated communication protocols are proposed in this paper. In this proposed architecture, most elements in the sensor network are designed to be equipped with no functions for message forwarding or channel scheduling. The local control center uses a centralized communication protocol to communicate with each sensor node. The local control center can also use ad hoc network technology to relay the data between each of the sensors. This approach not only minimizes the complexity of the sensor nodes implemented but also significantly reduces the cost, size and power consumption of each sensor node. In addition, the benefit of using ad-hoc network technology is that the local controller retains its routing capabilities. Therefore, power efficiency and communication reliability can be both achieved and maximized by this type of hierarchical sensor network.

Attempts to develop a Wireless Health Advanced Mobile Bio-diagnostic System (abbreviated as WHAM-BioS) have arisen from the need to monitor the health status of patients under long-term care programs. The proposed WHAM-BioS as presented here was developed by integrating various technologies: nano/MEMS technology, biotechnology, network/communication technology, and information technology. The biochips proposed not only detect certain diseases but will also report any abnormal status readings on the patient to the medical personnel immediately through the network system. Since long-term home care is typically involved, the parameters monitored must be analyzed and traced continuously over a long period of time. To minimize the intrusion to the patients, a wireless sensor embedded within a wireless network is highly recommended. To facilitate the widest possible use of various biochips, a smart sensor node concept was implemented. More specifically, various technologies and components such as built-in micro power generators, energy storage devices, initialization processes, no-waste bio-detection methodologies, embedded controllers, wireless warning signal transmissions, and power/data management were merged and integrated to create this novel technology. The design methodologies and the implementation schemes are detailed. Potential expansions of this newly developed technology to other applications regimes will be presented as well.

This paper presents a novel 802.11-based positioning system called the maximal cluster centered positioning system (MCCPS) developed and demonstrated at National Central University. The MCCPS system locates mobile objects via collecting the sensed power strengths of the mobile objects to multiple wireless access points. To overcome the serious multipath fading problem in the indoor environment, several positions called reference points were selected and a database is introduced to maintenance the power signature of each reference point. The experimental results show that the location information provided by MCCPS assures high correctness of region classification and low distance error.

In a mobile environment, a decision maker would usually like to query times, locations, and moving behaviors of certain mobile terminals. For example, a mobile transaction would like to know where is the next cell of its mobile clients and the probabilities that the mobile clients will move to the cells so that it could reserve appropriate channels for them. As a result, tracking the changing times and positions of mobile terminals capable of continuous movement is becoming increasingly necessary. However, current personal communication services (PCS) networks can only offer current maintained location information of non-idle mobile terminals. Pertinent researches predict location based on tangent velocity approaches. Location prediction based on tangent velocity is effective only within a short time interval. In this paper, we propose a model to model the moving behavior of each mobile terminal. From the moving behavior, we estimate and propose several location prediction functions for location query. The experimental results show that our proposed location prediction functions are accurate enough for regular moving mobile terminals.

We propose a new location tracking strategy called behavior-based strategy (BBS) based on each mobile's moving behavior. With the help of data mining technologies the moving behavior of each mobile could be mined from long-term collection of the mobile's moving logs. From the moving behavior of each mobile, we first estimate the time-varying probability of the mobile and then the optimal paging area of each time region is derived. To reduce unnecessary computation, we consider the location tracking and computational cost and then derive a cost model. A heuristics is proposed to minimize the cost model through finding the appropriate moving period checkpoints of each mobile. The experimental results show our strategy outperforms fixed paging area strategy currently used in the GSM system and time-based strategy for highly regular moving mobiles.

The hierarchical network structure significantly reduces the size and maintenance cost of routing table for huge networks. But in ad hoc networks, no fixed host leads to the challenge of the hierarchical structure, since the topology information needs to be updated dynamically due to membership changes caused by mobility. To construct the hierarchical structure of physical locations, we adopt a cluster infrastructure to partition the network into different groups for physical location maintenance. In order to construct the hierarchical structure of logical locations, all hosts are divided into several domains, each one of them has one corresponding domain location server to record all of the member physical locations (cluster locations). With the hierarchical structure, most necessary routing information can be ignored.

With the fast development of internet, the multicasting applications (such as Distant Learning) have become more and more important. Since multicasting multimedia information over the wired links might generate heavy traffic streams to cause congestion, the utilization of internet will be reduced dramatically. The satellite with broadcasting capability and high bandwidth could provide an alternate transmission way. Most of applications using satellite are unidirectional. However, the bi-directional interactive applications will be needed to provide instant interaction. However the transmission latency through satellite is considerably long and might lead to the loss of interactive ability. Therefore, we propose an intelligent routing strategy to overcome the high latency and enhance the interactive capability over satellite links. Especially, this routing method is compatible with Mbone. We compare this routing method with one-to—one and one-to-many transmission and analyze the result. The results show transmission efficiency has improved.