A Wi-Fi P2P communication platform between wireless LAN memory cards: Prototype implementation and performance evaluation

With the more and more severe air pollution, the corrosion phenomenon will also directly or indirectly influence the reliability of electronics. In order to ensure the anti-corrosion reliability requirement is enough even if the electronics were used in harsh environment. Therefore, it is necessary to evaluate the anti-corrosion capacity through accelerated corrosion test methodology. Print Circuit Board (PCB) pad design and Print Circuit Board Assembly (PCBA) material were often selected to research the corrosion phenomenon due to the in-field failure with creep corrosion. Besides, passive component and conformal coating have been also mentioned in several literatures in recent years. In general, the conformal coating seems a good system level solution which can protect the board and component to prevent the corrosion occurrence. But the solution is not suitable for gold finger and connector due to the electrical connection. To consider the high potential corrosion risks in gold finger and connector areas. Therefore, 30 um gold plating was often adopted to satisfy the anti-corrosion requirement in harsh environment in the industry. However, it is necessary to evaluate the porosity for metal coating quality even if the same thickness of gold plating. In this paper, the Flower of Sulfur (FoS) test was adopted to evaluate the metal coating porosity of gold finger for Secure Digital (SD) memory card. SD memory card is widely used in the various consumer electronic devices and also has become a widespread means of storing several gigabytes of data in a small size, including digital cameras, camcorders, and video game consoles, mobile phones and so on. In this paper, the gold finger area was selected to research the corrosion phenomenon and also followed FoS test with ASTM B809 standard. Several analytical methods were carried out in this work, including, Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX) and Coulometric Reduction (CR). Finally, we would like to verify the metal coating porosity of gold finger and also ensure that anti-corrosion capacity for various ready-made SD memory card.

This paper presents the implementation of a digital system to estimate the direction-of-arrival (DOA) of a sound source signal using the multichannel cross-correlation coefficient (MCCC) method. The implementation is based on a Nios <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> II soft processor incorporated in a four-microphone-channel signal processing system on a field-programmable gate array (FPGA). The MCCC algorithm is coded in C and executes on the Nios <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> II soft processor on an Altera <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> Cyclone <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> II FPGA. The performance of the soft-processor-based FPGA implementation of the MCCC algorithm is investigated by applying simulated microphone input signals from a pre-recorded sound source stored on a secure digital (SD) memory card. The results for noisy and reverberant environments are in good agreement with simulations and they confirm that the DOA estimation robustness is suitable for practical applications.

This paper provides a clone resistant mutual authentication between Secure Digital (SD) memory cards and host devices. The existing mutual authentication using one broadcast encryption can not resist cloning attacks. Therefore, a new clone resistant mutual authentication is proposed by using two broadcast encryption with the traitor tracing algorithm.

The ubiquitous nature of Bluetooth equipped devices has made it opportunistic to scavenge information that can be repurposed for applications other than initially intended. One such opportunity is in vehicular traffic monitoring, whereby sampling of Bluetooth radios serve as proxies for vehicles and consequently for traffic density and flow. This paper discusses a complete data collection system developed at the University of Manitoba that utilizes a variety of wireless networking technologies and devices to collect inferred traffic data at an intersection along a major thoroughfare in an urban setting. Specifically, a wireless sensor network of slave probes was designed and implemented with the objective to collect Bluetooth device information for this purpose. To facilitate easy setup and a long battery life, a solar-powered probe design was investigated. Data from each slave probe is communicated to a master node through XBee communication, where it is stored on a secure digital (SD) memory card before being transmitted to a central server every five minutes over a global system for mobile communications (GSM) cellular network. The server parses the data received and stores it in a database. Consumer and corporate websites may then access this database to display archived data or current data in real-time to various users.

Cloud computing suggests that we can move computers from the desktop onto the network. In this article, we investigate whether we can do the same with digital imaging devices. After all, for most of us, the practical management of local storage on digital cameras is a messy business, keeping track of all those secure digital (SD) memory cards and then figuring out which computer they are stored on. For most family units or socially organized groups, the sensible end point for a collection of images is on shared network storage where everyone can access and contribute to the image collection. So, we consider 1) the current state of art in device connectivity; 2) the current status of digital imaging devices and image/video data requirements; and 3) we put together a proof of concept to test our hypothesis that cameras do not really need local storage any more, and yes, you could actually start to put your photographs directly into the clouds.

Vehicle dashboard cameras are becoming an increasingly popular kind of automotive accessory. While it is easy to obtain the high-definition video data recorded by dashcams using Secure Digital memory cards, this data is rarely used except for safety purposes because it takes substantial time and effort to review or edit many hours of such recorded videos. In this paper, we propose a new usage for this data through the automatic video editing system we have developed that can create enjoyable video summaries of road trips utilizing video and other data from the vehicle. We also report the results of comparisons between automatically edited videos created by the proposed system and manually edited videos created by study participants. The prototype developed in this study and the findings from our experiments will contribute to improving the driving experience by providing entertainment for automobile users after road trips, and by memorializing their travels.

A Novel Wearable Real-Time Sleep Apnea Detection System Based on the Acceleration Sensor

The signal acquisition system (SAS) operated by battery is designed in this paper. SAS includes signal acquisition and statistics function based on movement joints of basketball player. SAS is a recording of the electrical activity of the brain and pulse from the scalp and the recorded waveforms provide insights into the dynamic aspects of brain activity. The amplified SAS signals are digitized by an A/D converter. The digitized signal is transmitted to PC by a wireless serial port or stored in secure digital memory card. Experimental result shows that the system could implement the acquisition and storage of the foot compressive mechanical characteristics signals efficiently. This system would be of benefit to all involved in the use of SAS for sports training.

Wireless local area networks (WLANs) for public access need to provide privacy between users and also ensure correct charging where access is based on payment. However, by design, conventional LANs and WLANs provide directs unmediated communications between networked devices at the link layer. The paper presents a method to allow networked client devices to communicate with a network comprising routers and other servers while preventing unmediated communication between the clients on the wireless network. An advantage of the method is that it can be implemented entirely within the WLAN access point as a configurable forwarding policy database. No changes are needed to the WLAN client software or the routers and servers and the communication remains completely within the scope of existing industry standards.

This paper proposes a frame queuing algorithm to improve scalability and manageability for the quality of service (QoS) guaranteed wireless LAN (WLAN) access point (AP) using a simple mechanism. The IEEE 802.11e standard can be used as QoS-guarantee technology in the existing WLAN communication. However, if a lot of terminals access the same AP such as in a public WLAN access environment, an AP that supports the IEEE 802.11e standard cannot provide adequate QoS-guaranteed communication. This is because the AP's capability depends on the allocated communication time of wireless channels per unit of time, and the allocated time is determined by the WLAN's physical data speed and the frame size of the service application. So we propose a frame queuing algorithm considering these features of WLAN's commutation and apply it to the 802.11e standard. And we evaluate it by the computer simulation and confirm its advantage.

Currently, Internet of Things (IoT) has become common in various applications, including smart factories, smart cities, and smart homes. In them, wireless local-area networks (WLANs) are widely used due to their high-speed data transfer, flexible coverage ranges, and low costs. To enhance the performance, the WLAN configuration should be optimized in dense WLAN environments where multiple access points (APs) and hosts exist. Previously, we have studied the active AP configuration algorithm for dual interfaces using IEEE802.11n and 11ac protocols at each AP under non-channel bonding (non-CB). In this paper, we study the algorithm considering the channel bonding (CB) to enhance its capacity by bonding two channels together. To improve the throughput estimation accuracy of the algorithm, the reduction factor is introduced at contending hosts for the same AP. For evaluations, we conducted extensive experiments using the WIMENT simulator and the testbed system using Raspberry Pi 4B APs. The results show that the estimated throughput is well matched with the measured one, and the proposal achieves the higher throughput with a smaller number of active APs than the previous configurations.

With the fast-growing demand for mobile services, where to place the access points (APs) for providing uniformly and appropriately distributed signals in a wireless local area network (WLAN) becomes an important issue in the wireless network planning. Basically, AP placement will affect the coverage and strength of signals in a WLAN. The number and locations of APs in a WLAN are often decided on the basis of the trial-and-error method. Based on this method, the network planner first selects suitable locations to place APs through observation, and then keeps changing the locations to improve the signal strength based on the received signal. Such process is complicated, laborious and time-consuming. To overcome this problem, we investigate the back-propagation neural network (BPNN) algorithm to improve over the traditional trial-and-error method. Without increasing the number of APs, our approach only needs to adjust AP locations to overcome weak signal problems and thus increase the signal coverage for the Internet connection anywhere within the area. In our experiment, we established a WLAN on a C campus. Our experiments also indicate that placing APs according to the BPNN provided better signal coverage and met the students’ demands for connecting to the Internet from anywhere in the classroom.

The aim of this study is to compare water depths measured by manually and PLC from a Class A Pan in field conditions using ultrasonic transducer. The study was conducted in garden of Faculty of Agriculture, University of Kahramanmaras Sutcu Imam in the summer season of 2019. A steel meter was used to measure water depth manually in the evaporation pan. Using the ultrasonic transducer, PLC measured water depth from the evaporation pan between 140 and 223 mm water depth at 8:00 am. An ultrasonic transducer is attached one end of sliding buttress, at which was 50 cm above from its inner-bottom at the center of the evaporation pan. The ultrasonic transducer was set to be able to read water depth and calibrated using sliding buttress. A program was written in CODESYS-ST language to measure the water depth from a Class A Pan using PLC, which was connected the ultrasonic transducer and uploaded to PLC. With the program, digital water depths were converted to millimeter water depths. To be able to read the water depth more accurately, each depth value read by the PLC was determined by averaging 30 measurements made successively at 300 millisecond intervals. In this processes, moving average method was used. Water depth measured by PLC was saved on the SD (secure digital memory) card. In the manual water depth measurements, there were 26 observations. The water depths on the manual measurement dates were matched with the water depths measured by PLC. A regression analysis was performed between the water depths measured by the steel meter and PLC in the pan, and determination coefficient (R2) was result as 0.96. The Mean Absolute Percent Error (MAPE) of these two data sets was calculated as 2.3%. The level of agreement between the two data sets; if the MAPE is below 10%, it is considered “very good”. The results of this study revealed that the PLC could measure the water depth close to the measured manually water depth in the evaporation pan with an ultrasonic transducer.

Dashcams are critical devices for ensuring transportation safety. Specifically, they provide onsite records for transportation incidents, which allows investigators to analyze the causes of the incidents. Therefore, dashcams are commonly used in public transport, automobiles, and motorcycles. Current dashcams can achieve 1080p and 4K resolution. In addition to high-resolution charge-coupled devices and components, dashcams require a powerful video encoder integrated circuit to encode images. The results obtained after image encoding are stored in memory cards or other digital memory components. The difference between commercial dashcams and general surveillance cameras lies in their memory components. The memory components of surveillance cameras are typically cheap and easily obtainable Secure Digital (SD) cards and flash ICs, whereas dashcams require small and cheap memory components. In contrast to general surveillance equipment, dashcams do not contain a large-scale hard drive matrix and do not have access to a large server for maintaining records. Thus, dashcams must achieve an effective compression efficiency without causing distortion. Most SD cards on the market have a storage size of 8–64 GB. Advances must be achieved in image compression technology so that the image compression ratio can be increased to reduce the video size without causing problems in subsequent image reading and identification. In this study, the file compression ratio achieved with the developed technology was 1.7–2.1 times higher than that achieved without the application of this technology. Moreover, the storage space saving ratio of the aforementioned technology was 42%–53%.

With the wide applications of the Internet of Things (IoT) in smart home systems, IEEE 802.11n Wireless Local Area Networks (WLANs) have become a frequently chosen communication technology due to their adaptability and affordability. In a high-density network of devices such as the smart home scenerio, a host often meets interferences from other devices and unequal Received Signal Strength (RSS) from Access Points (APs). This results in throughput unfairness/insufficiency problems between hosts communicating concurrently in WLAN. Previously, we have studied the throughput request satisfaction method to address this problem. It calculates the target throughput from measured single and concurrent throughputs of hosts and controls the actual throughput at this target one by applying traffic shaping at the AP. However, the insufficiency problem of maximizing the throughput is not solved due to interferences from other hosts. In this paper, we present an extension of the throughput request satisfaction method to maximize the throughput of a high-priority host under concurrent communications. It recalculates the target throughput to increase the actual throughput as much as possible while the other hosts satisfy the least throughput. For evaluations, we conduct experiments using the test-bed system with Raspberry Pi as the AP devices in several topologies in indoor environments. The results confirm the effectiveness of our proposal.