433 MHz 數位無線收發機之測向系統與火災警報系統實現

This thesis is devoted to the investigation and realization of an 868.35 MHz two-way digital RF transceiving system, including design of the 2-way communication firmware encoding/decoding algorithms associated, performance optimization of the RF transceiver module used, and design of a planar antenna of reduced length. The format of the wireless data packet basically includes the following various fields: training preamble, sync header, payload data, frame check sequence, and stop symbol. In any open wireless communication channel, nature-generated and human-made noises are ubiquitous. In order to enhance the performance reliability and system range of the digital wireless communication system under study, the 2-way encoding/decoding communication firmware has to be embedded with effective real-time noise-robust digital signal processing algorithms. In this thesis, The Cyclic Redundancy Check sequence is adopted as the error-detecting mechanism, Hamming coding and the error syndromes/error patterns associated are used to provide the necessary error-correcting capability. In view of the intermittent burst noise created by other radio users, interleaving/de-interleaving techniques are utilized to effectively spread out the burst errors possible.Moreover, a 2-way digital wireless communication protocol is designed so as to demonstrate the 2-way communication capability and facilitate the subsequent 2-way ping-pong range test. Since all the foregoing encoding, decoding, and anti-noise tasks for the wireless data packets to be communicated are realized with the aid of a microcontroller and the assembly language, the microcontroller, RF transceiver module, and antenna are finally integrated and put to 1-way and 2-way range tests in open site or space.

The fire detection system combines the simultaneous measurements of smoke, carbon monoxide, and carbon dioxide. The security of campus against intruders moving in laboratories, class rooms, staffrooms or washrooms. The fire alarm system consists of Fire detectors (with can be smoke detector, heat, or Infra-Red detectors), control unit and alarm system. A fire detection system is developed based on the simultaneous measurements of temperature and smoke. The fire detection system with the alarm algorithm detected fires that were not alarmed by smoke sensors, and alarmed in shorter times than smoke sensors operating alone. Previous fire detection algorithms used data from sensors for temperature, smoke, and combustion products. The smoke sensor alarms when the analog output signal exceeds or equal the threshold value. The node includes analog sensors to measure smoke, carbon monoxide (CO) and temperature. A fire alarm system should reliably and in a timely way notify building occupants about the presence of fire indicators, such as smoke or high temperatures.

This paper proposes a system that estimates crowdedness, such as the numbers of people and wireless communication devices, from the received signal strength indication (RSSI), which is measured using sensor nodes already-deployed for a different purpose. For example, the system estimates crowdedness using sensor nodes of structural health monitoring. Our system consists of two parts: an RSSI synchronous measurement and a crowdedness estimation algorithm. The RSSI synchronous measurement enables us to measure and collect two kinds of RSSI by synchronized RSSI sampling: the inter-node RSSI and surrounding RSSI. The crowdedness estimation algorithm estimates the number of people from the collected inter-node RSSI and the number of wireless communication devices from the collected surrounding RSSI in a location. We evaluated the proposed system in the laboratory at Osaka University. The evaluation results demonstrate that the system estimates the presence or absence of people in the laboratory with approximately 92% accuracy and the number of people with approximately 79% accuracy, with errors of up to two people.

This research work provides an in-depth analysis of the fire alarm system, considered as a security tool for a variety of facilities, from industrial buildings to residential premises. Two key subsystems serve as the basis for the study: the fire alarm system, which is designed to detect and report the occurrence of fire, and the intrusion alarm system, whose task is to detect attempts at illegal intrusion. For each of these subsystems, their functions and components are investigated, their mechanism of action, principles of operation, and possible implementation options are described, depending on the specific conditions and security requirements. At the same time, emphasis is placed on three types of automatic fire alarm systems: threshold, addressable and addressable-analog, each of which has its own features, advantages and disadvantages. The article goes beyond theoretical analysis and presents the results of a practical study of the three main types of fire alarm systems: wired, wireless and addressable. The study is based on a specially designed training stand, which allows you to simulate the operation of fire alarm systems in conditions as close to reality as possible. The article demonstrates the connection schemes of detectors, explains their states in the "normal" and "alarm" modes. It is noted that the currents and voltages of alarm loops in different modes were measured. Dependency diagrams of these parameters are presented, and the alarm threshold levels are measured. The research presented in the paper provides a valuable contribution to the study and optimization of alarm and fire systems, providing meaningful data for the development and testing of these systems. The paper can be useful for fire and security professionals and those interested in improving the performance of these systems.

Chapter 6 - Fire Alarm Systems

Performance characteristics and assessment of fire alarm system

The article presents issues related to the use of electronic security systems (ESB) on a vast railway area. These systems are operated in very different environmental conditions. Due to the fact that electrical and electronic systems coexist on the extensive railway area for various purposes - e.g. power supply systems for railway traction, rail traffic control systems (SRK), electronic security systems - fire alarm system (SSP), CCTV system (CCTV), access control system (SKD), a significant operational problem in addition to environmental changes in which the above-mentioned technical facilities are used, there is also the issue of electromagnetic compatibility. Depending on the area extent of the railway area, construction, technical configuration, way of alarming, safety classes of these systems may be different. In SSP there is another factor that affects the configuration of these systems, namely the so-called fire scenario and how to notify the State Fire Service (PSP) about an existing fire risk or damage. There are several different ESB structures - focused, distributed and mixed. The type of ESB used in a given railway facility - construction or open area is conditioned by its cubic capacity [m3], terrain extent [m2 or km2] and the number of supervised facilities. The use of a given type of ESB to ensure safety and fire protection in a given railway area also depends on the requirements of legal provisions for the object(s), the fire scenario that must be implemented by the system, legal requirements for the given protected area, the accepted scope of protection and the reliability and operational requirements to be met by these installations. The article presents basic issues related to ESB operation that are used in the selected railway area. The review of technical solutions of selected ESBs and the methodology of conducting the analysis for the purposes of developing, e.g. fire scenario or hazard analysis, presented in the article, will enable railway facility designers to properly develop design assumptions.

An accurate prediction method for moving target localization and tracking in wireless sensor networks

Aim: The aim of this paper is to present the construction and principle of operation of condensed aerosol generators, as well as a review of their selected characteristics, confirmed in the process of assessment and verification of constancy of performance. The paper describes selected laboratory tests, including those specific to Group A, B and C fires. Introduction: Fixed firefighting systems, in addition to detection systems (fire alarm system) and alarm systems (voice evacuation systems), are one of the pillars of the safety of today's erected, increasingly complex buildings. However, unlike these detection and alarm systems, fire extinguishing systems based on condensed aerosol generators focus on providing an adequate level of protection for property, as they are dedicated to spaces that are not normally occupied. For this reason, emphasis is placed on the reliability of the generators, whose only task is to trigger appropriately at a specific time and fill the protected area with aerosol. Methodology: The theoretical research, such as analysis of literature and legal documents, synthesis, generalisation, inference, comparison and analogy, was used in the development of the paper. A review of selected characteristics validated in the process of assessment and verification of constancy of performance of the analysed products was carried out. Research processes relating to selected parameters of the generators and inherent in the conformity assessment of construction products are presented. Conclusions: It should be noted that, irrespective of their main purpose, condensed aerosol generators, which are a key component of aerosol fire extinguishing kits, can be crucial not only with regard to the safety of the buildings themselves, but also of their users, influencing the containment of a fire in the extinguishing zone where they are installed. Also, important is the awareness of owners and managers of building structures equipped with condensed aerosol generators. Their particular attention should be directed to the specifics of the generator itself and their knowledge of its operating principles. In the next stages of the work, it will be crucial to define the basics related to the connection of the generators to the installation forming a fixed firefighting system, to identify and describe issues related to design, installation and maintenance, and to identify the risks related to the potential exposure of the users of built structures to the extinguishing aerosol.

Fire can really be devastating to properties if improperly managed, it is due to this problem that the fire detection and alarm systems were sought for. However, traditional fire alarm system is based on a wiring network which have drawbacks and limitations such as inflexibility of the FDAS layout plan during building construction, and difficulties in renovation where the removal and relocation of traditional FDAS requires additional amount of work. To address these problems, a fire detection and alarm system that is based on wireless sensor network was developed. The FDAS is mainly composed of a fire detection node, a fire alarm node, and a fire alarm control panel. The wireless communication of the nodes was achieved using XBee as the wireless transceiver. The significant characteristic of XBee is the mesh routing protocol which helps the system to be more robust and flexible. The fire alarm control panel is a LabVIEW based program that utilizes the state machine architecture which follows the detect-evaluate-store algorithm. In evaluating the overall system, results illustrate the network of nodes adapts to its location and connects to other nodes whenever it is within their range. Furthermore, the average response time of each detection node with respect to the fire alarm control panel is below the standard of 10-second as stated by the National Fire Alarm and Signaling Code.

Vulnerability analysis has always been an integral part of disaster risk assessment. This study aims to assess the physical vulnerability of public school buildings against flooding. It discusses the vulnerable elements or attributes, the extent of damages incurred during flood events, the damage response, and the future steps that must be taken to increase flood resiliency. The study used empirical data collection using semi-structured interviews to characterize the common types of public schools and to collate the damage responses. Quantity surveying was performed to measure the amount of damages related to different flood depths. Structural damages to public school buildings are not expected for flood heights ranging from ground level up to ten (10) m. However, damages are incurred by building finishes and fixtures. Floors, walls, and septic system are cosmetically damaged. Vulnerable components include wooden elements like doors, cabinets, blackboards and ceiling, and electrical fixtures such as wiring, lighting, outlets, switches, and fire alarm system. Comprehensive vulnerability description of public school buildings were represented as curves of flood depth vs. damage index. The damage ratio decreases as the number of floors increase. Maximum damage to one-story building is 23.6% while at 15.02% for four-story school building. This study is an attempt to promote further research of the subject matter in developing countries towards flood resiliency in the built environment.

The paper is concerned with the features of the PLC-technology and describes the common circuit solutions of data communication devices along power lines. The research group proposes an original type of a data communication device based on making use of new physical phenomena, which have never been applied in the PLC-technology before. An inverted magnetoelectric effect in multidimensional composition material is used to transmit a signal; this effect is a combination of the piezomagnetic and the piezoelectric effects connected by elastic interactions. The proposed data communication device does not have either a transformer or a galvanic coupling between the power high-voltage line and the low-voltage information lines, thus eliminating the influence of the high operating voltage of the power line on the low-voltage lines of high-frequency equipment. The proposed variant of the data communication device can be easily incorporated into standard high-frequency equipment, thus providing higher quality level of its operation. The developed data communication device was tested by experiment as part of an experimental security and fire alarm system.

The article examines the requirements for the functional purpose of access control and management systems (ACMS), the functional composition of ACMS and general requirements for it, integration and network construction of ACMS, burglar alarm systems, fire alarm systems, access control and management systems, ACMS capabilities, control systems access control, video surveillance systems.

Sewer pipe deterioration is a severe problem in many countries, and sewer pipe inspections are essential for maintaining sewer systems. Various sewer inspection methods, such as a visual check, boat-type video cameras, and remote robots with or without a wired connection, exist. However, they each suffer from problems, such as high labor costs, long waiting times when using boat-type video cameras, and the purchasing cost of robots. To achieve low-cost, safe, and near real-time inspections of sewer pipes, we have proposed a sewer inspection method based on a drifting wireless camera and sensor nodes. Drifting nodes capture a video of the inside of pipe while drifting on a current in the sewer and access points (AP) installed under manholes receive video data from drifting nodes and send data to an online server on the Internet. For the video inspection using our proposed system, the information of the position of camera/sensor nodes while they drifting is essential because video data need to link to the location information to help to detect damaged points of pipes. However, the camera/sensor nodes cannot utilize the GNSS because signals from GNSS satellite do not reach to the space in underground sewer pipes. In this paper, to investigate the usefulness of the receive signal strength indicator (RSSI) observed by drifting camera/sensor nodes for the position estimation in 200mm-diameter pipes, we performed experiments to measure the RSSI of a wireless communication device drifting on water in an experimental underground pipe. The measurement results show that RSSI monotonically increases when a drifting device approaches the AP and monotonically decreases when it leaves the AP, and the distribution of measurement value suggests that possibility of position estimation with an error of lm order.

Fire alarm systems are an important part of the safety concept in complex buildings. For this reason, there are high availability requirements for the systems, which must be sustained by a maintenance concept. A shortage of skilled workers and rising costs in the construction and operation of buildings are pushing these concepts ever further. This study deals with proposed changes to the maintenance strategies to achieve cost and time savings in addition to an improvement in quality. As a first part of the work, the current state of research on developments in fire alarm systems and their maintenance and inspection concepts is analyzed within a literature review. The results serve as a basis for further research, which is based on a qualitative content analysis of expert interviews and standardized surveys to identify the weaknesses in current inspection strategies and future factors influencing the methods and technology of inspections through technical innovations. As a data basis for this study, expert interviews were conducted with experts from manufacturers, industry associations, and standards bodies in order to determine the possible influencing factors. To determine their relevance for the inspection, more than 40 experts were surveyed about testing the systems. The presented results show that new technical risks, such as cyber threats and networked plant structures, are insufficiently covered by current inspection strategies. Furthermore, inspection steps can be substituted by new technologies. The most important influencing factors that can be identified here are automatic self-test functions of components and remote inspection techniques of the systems. Finally, the results are discussed within the framework of a PESTEL analysis. In conclusion, it can be stated that the integration of identified impacts in future inspection strategies brings time and efficiency benefits in the operation of systems.