Vibration Alert Bracelet for Notification of the Visually and Hearing Impaired

This paper presents the prototype of an electronic vibration bracelet designed to help the visually and hearing impaired to receive and send emergency alerts. The bracelet has two basic functions. The first function is to receive a wireless signal and respond with a vibration to alert the user. The second function is implemented by pushing one button of the bracelet to send an emergency signal. We report testing on a prototype system formed by a mobile application and two bracelets. The bracelets and the application form a complete system intended to be used in retirement apartment communities. However, the system is flexible and could be expanded to add new features or to serve as a research platform for gait analysis and location services. The medical and professional potential of the proposed system is that it offers a simple, modular, and cost-effective alternative to all the existing medical devices with similar functionality currently on the market. The proposed system has an educational potential as well: it can be used as a starting point for capstone projects and demonstration purposes in schools to attract students to STEM disciplines

Embedded Sensor System for Early Pathology Detection in Building Construction

Structure pathology detection is an important security task in building construction, which is performed by an operator by looking manually for damages on the materials. This activity could be dangerous if the structure is hidden or difficult to reach. On the other hand, embedded devices and wireless sensor networks (WSN) are becoming popular and cheap, enabling the design of an alternative pathology detection system to monitor structures based on these technologies. This article introduces a ZigBee WSN system, intending to be autonomous, easy to use and with low power consumption. Its functional parts are fully discussed with diagrams, as well as the protocol used to collect samples from sensor nodes. Finally, several tests focused on range and power consumption of our prototype are shown, analysing whether the results obtained were as expected or not

Fire and Life Safety Analysis: San Francisco Museum of Modern Art

A fire and life safety analysis was conducted to fulfill a requirement for the Master of Science Degree in Fire Protection Engineering from California Polytechnic State University. A prescriptive and performance-based analysis was conducted on the San Francisco Museum of Modern Art. The SFMOMA is a 10-story, 460,000 2 , Type 1A mixed occupancy building. Located in the northwest corner of San Francisco, SFMOMA houses a collection of over 33,000 works of painting, sculpture, design and media making it one of the largest museums in the world for modern and contemporary art. Four features of the prescriptive based analysis include: (1) Egress and Design Analysis, (2) Structural Fire Protection, (3) Water-Based Suppression System, and (4) Fire Alarm and Detection These four features were performed in order to determine whether the building complies with applicable codes and standards. The 2016 California Building Code, 2016 California Fire Code, and current National Fire Protection Association (NFPA) standards were used for the prescriptive based analysis. After completing the analysis of the museum, it was concluded, based on the available data acquired, that the building met the minimum requirements set forth in the building code, fire code, and national standards. Performance based analysis was used to determine whether the fire safety features of the building met the design goals in accordance with 2016 California Building Code, 2016 California Fire Code, and 2018 NFPA 101. The museum recognizes that the protection of life and limb override the protection of art. In doing so, the life safety options set forth in the 2018 NFPA 101 were used: (1) Section 5.5.3.2 – An ultrafast developing fire, in the primary means of egress, with interior doors open at the start of the fire. It addresses the concern regarding a reduction in the number of available means of egress (2) Section 5.5.3.3 – A fire that starts in a normally unoccupied room, potentially endangering a large number of occupants in a large room or other area. It addresses the concern regarding a fire starting in a normally unoccupied room and migrating into the space that potentially holds the greatest number of occupants in the building. Two design fires were provided in the performance-based analysis. Pyrosim and Pathfinder were two computer modeling programs used to calculate time to tenability criteria and time for occupants to exit the building. First design: A fire in the atrium followed the guidelines for life safety compliance option Section 5.5.3.2. The fire was assumed to grow as a fast growing t-squared fire curve to a peak heat release rate of 5,000 kW. This peak heat release rate was chosen based on the assurance that fuel packages in the museum would not exceed 5,000kW. The fire was also assumed to stop growing and to maintain steady state conditions at the time of sprinkler activation or at the peak heat release rate. The soot and carbon monoxide (CO) yield inserted into FDS was data gathered from the Society of Fire Protection Engineers (SFPE) Handbook 5th Edition. Data gathered from Pyrosim, Pathfinder, and British Standard Study from 1997 (pre-movement time) calculated the required safe egress time for the 1st floor at 818 seconds and 515 seconds for 7th floor. The results from Pyrosim showed that visibility, CO concentration, and temperature never reached tenability criteria for the design fire (ASET equaled to ∞). With ASET (∞) \u3e RSET (818 seconds and 515 seconds), the fire safety features for design fire #1 passed the performance-based analysis. Second design: A fire on the 8th floor office level located in a storage room follows the guideline for life safety compliance option Section 5.5.3.3. The materials for the fire were modeled after a 4- unit workstation (small filing cabinets, telephones, computers, modest amount of office paper, and desks made of metal frame construction with plastic trim parts). The heat release rate data was provided in the 2016 SFPE Handbook at a peak Heat Release Rate (HRR) set at 3000 kW. In addition to the workstation, 2 swivel chairs, with a peak heat release rate of 450 kW, was added. Calculations for this fire were based on medium alpha t-squared fire with a max/combined HRR of 3000 kW. The predominant material for office furniture was assumed to be flexible polyurethane foam with the highest carbon monoxide and soot yield. In referencing the SFPE Handbook, the worst yields came from GM27 polyurethane. Results from Pyrosim provided a sprinkler activation time of 191 seconds at a heat release rate of 567 kW. Using 567 kW as a steady state HRR upon sprinkler activation, the results from Pyrosim determined that tenability criteria for soot visibility, CO concentration, and temperature were never reached in the design fire (ASET equaled to ∞). Pathfinder and data gathered from the British Standard study in 1997 determined a required safe egress time (RSET) at 522 seconds. With ASET (∞) \u3e RSET (522 seconds), the fire safety features for design fire #2 passed the performance-based analysis. Although the fire and life safety system design of the museum passed both the prescriptive and performance-based analysis, continued analysis should be conducted as changes within the museum occur. Recommendations would include: (1) Using smaller mesh size for more precise modeling, (2) updating the model to correctly match the detailed architectural design, (3) provide a 20-minute duration analysis for the design fires, and (4) changing behavior movement patterns in Pathfinder to accurately depict occupants with slower movement times. With better understanding of smoke control in Pyrosim and behavior pattern in Pathfinder, more precise modeling can be conducted in order to provide more accurate results

Quarantine region scheme to mitigate spam attacks in wireless sensor networks

The Quarantine Region Scheme (QRS) is introduced to defend against spam attacks in wireless sensor networks where malicious antinodes frequently generate dummy spam messages to be relayed toward the sink. The aim of the attacker is the exhaustion of the sensor node batteries and the extra delay caused by processing the spam messages. Network-wide message authentication may solve this problem with a cost of cryptographic operations to be performed over all messages. QRS is designed to reduce this cost by applying authentication only whenever and wherever necessary. In QRS, the nodes that detect a nearby spam attack assume themselves to be in a quarantine region. This detection is performed by intermittent authentication checks. Once quarantined, a node continuously applies authentication measures until the spam attack ceases. In the QRS scheme, there is a tradeoff between the resilience against spam attacks and the number of authentications. Our experiments show that, in the worst-case scenario that we considered, a not quarantined node catches 80 percent of the spam messages by authenticating only 50 percent of all messages that it processe

Auditory neuroscience: Development, transduction and integration

Hearing underlies our ability to locate sound sources in the environment, our appreciation of music, and our ability to communicate. Participants in the National Academy of Sciences colloquium on Auditory Neuroscience: Development, Transduction, and Integration presented research results bearing on four key issues in auditory research. How does the complex inner ear develop? How does the cochlea transduce sounds into electrical signals? How does the brain's ability to compute the location of a sound source develop? How does the forebrain analyze complex sounds, particularly species-specific communications? This article provides an introduction to the papers stemming from the meeting