Computer vision-based object recognition for the visually impaired in an indoors environment: a survey

Though several electronic assistive devices have been developed for the visually impaired in the past few decades, however, relatively few solutions have been devised to aid them in recognizing generic objects in their environment, particularly indoors. Nevertheless, research in this area is gaining momentum. Among the various technologies being utilized for this purpose, computer vision based solutions are emerging as one of the most promising options mainly due to their affordability and accessibility. This paper provides an overview of the various technologies that have been developed in recent years to assist the visually impaired in recognizing generic objects in an indoors environment with a focus on approaches based on computer vision. It aims to introduce researchers to the latest trends in this area as well as to serve as a resource for developers who wish to incorporate such solutions into their own work.     

Voice comparison between smokers and non-smokers using HMM speech recognition system

Automatic speech recognition is a technology that allows a computer to transcribe in real time spoken words into readable text. In this work an HMM automatic speech recognition system was created to detect smoker speaker. This research project is carried out using Amazigh language for comparison of the voice of normal persons to smokers one. To achieve this goal, two experiments were performed, the first one to test the performance of the system for non-smokers for different parameters. The second experiment concern smokers speakers. The corpus used in this system is collected from two groups of speaker, non-smokers and smokers native Morocan tarifit speakers aged between 25 and 55 years. Our experimental results show that we can use our system to make diagnostic for smoking people and confirm that a speaker is smoker when the observed recognition rate is below 50%.     

Ensembling of text and images using Deep Convolutional Neural Networks for Intelligent Information Retrieval

Wireless Personal Communications - Information retrieval (IR) defines the process of searching and attaining specific information resources which are related to the specific information...     

Cluster-based location service schemes in VANETs: current state,challenges and future directions

Vehicular Ad hoc Networks (VANETs) have drawn incredible interest in both academic and industrial sectors due to their potential applications and services. Vehicles’ position plays a significant role in many location-based applications and services such as public emergency, vehicles tracking, resource discovery, traffic monitoring and position-based routing. A location service is used to keep up-to-date records of current positions of vehicles. However, locating vehicles’ positions and maintaining an accurate view of the entire network are quite challenging tasks due to the high number of nodes, and high and fast nodes mobility which results in rapid topological changes and sudden network disconnections. In the past literature, various location-based services have been proposed to solve the above mentioned issues. Moreover, the cluster-based location service schemes have gained a growing interest due to their advantages over non-cluster-based schemes. The cluster-based schemes improve the network scalability, reduce the communications overhead and resolve the mobility issues within the clusters preventing them from propagating in the whole network. Therefore, this paper presents the taxonomy of the existing location service schemes, inspects the cluster-based location service by highlighting their strengths and limitations, and provides a comparison between location-based clustering and application specific clustering such as the one used in routing, information dissemination, channel access management and security. In addition, the existing clustering schemes, challenges and future directions for efficient cluster-based location service are also discussed.

     

Maximizing WSN Life Using Power Efficient Grid-Chain Routing Protocol (PEGCP)

Wireless Personal Communications - Recently, wireless sensor networks (WSNs) attracted the attention of searchers, due to the critical role in several applications like environmental monitoring,...     

Multiclass AQM on a TCP/IP router: A control theory approach

Active queue management (AQM) is a well‐known technique to improve routing performance under congested traffic conditions. It is often deployed to regulate queue sizes, thus aiming for constant transmission delay. This work addresses AQM using an approach based on control theory ideas. Compared with previous results in the literature, the novelty is the consideration of heterogeneous traffic, ie, multiclass traffic. Thus, each traffic class may have different discarding policies, queue sizes, and bandwidth share. This feature brings the proposal nearer to real network management demands than previous approaches in the literature. The proposed technique assumes that each class already has a simple controller, designed a priori, and focuses on designing a static state‐feedback controller for the multiclass system, where the design is based on using LMIs for the calculations. For this, optimization problems with LMI constraints are proposed to compute the state‐feedback gains that ensure stability for a large set of admissible initial conditions. These conditions ensure not only closed‐loop stability but also some level of performance. As far as we know, this is the first control theory based approach for the AQM problem on TCP/IP routers that allows a multiclass AQM while also considering time‐varying delays and input saturation. This is an important step to frame AQM in a more formal, yet realistic context, enabling it to address important service level agreement (SLA) directives. The proposal is tested on a simulated system at the end of this paper, showing the feasibility and performance of the approach in the presence of multiclass traffic.     

Degradation Mechanism and Stability Improvement Strategy for an Organic Laser Gain Material 4,4′‐Bis[(N‐carbazole)styryl]biphenyl (BSBCz)

The organic material 4,4′‐bis[(N‐carbazole)styryl]biphenyl (BSBCz) is an excellent gain medium for laser devices. However, BSBCz laser output quickly degrades during photoexcitation, which is an issue that must be overcome before it can be used for practical applications. In this study, the photodegradation mechanisms of BSBCz are investigated with the aim of enhancing its excited‐state stability. The photodegradation of BSBCz is attributed to instability of the triplet excited states that would occasionally decompose into other species. This decomposition reduces absorption and introduces exciton quenchers. Incorporating the triplet managing material 9,10‐di(naphtha‐2‐yl)anthracene (ADN) into BSBCz films greatly improves photoluminescence and amplified spontaneous emission stability because of the effective removal of the unstable triplets by ADN. This triplet managing method makes it possible to increase operational stability for BSBCz‐based organic light‐emitting diodes. Therefore, these results will contribute toward the fabrication of stable optically and electrically pumped organic laser diodes.     

Electrochemical study of modified non-functional bis-silane layers on Al alloy 2024-T3

In the last few years great efforts have been made in order to find and to develop environmentally friendly substitutes for Cr⁶⁺ pre-treatments applied on aluminium alloys used in the aircraft industry. Among the potential substitutes, silane layers have attracted considerable interest from researchers and from the industry. The present work investigates the anti-corrosion behaviour of (bis-1, 2-(triethoxysilyl) ethane (BTSE)) silane layers modified with Ce ions and/or silica nanoparticles applied on Al alloy 2024-T3 substrates. The corrosion behaviour was investigated in 0.1 M NaCl solution via d.c. polarization and electrochemical impedance spectroscopy (EIS). Contact angle measurements and XPS were used to assess information on the chemistry of the silane pre-treated surfaces. The results have shown that the introduction of additives improves the corrosion protection properties of the silane layer.     

Antioxidant and antiproliferative activity of polyphenols in novel high-polyphenol grape lines

Health-beneficial effects of grape and wine consumption have been linked to the presence of various polyphenols including anthocyanins in these products. The anthocyanin levels of red grape varieties can vary significantly and there is an interest in developing grape varieties with high anthocyanin levels. In this study, antioxidant and antiproliferative effects of grape anthocyanins from a group of selected grape lines designated as V 72, V 83 and V 103 developed through traditional breeding of the parent lines Lomanto and Seibel 8357, were investigated. The total anthocyanin levels in the different “Vintinto” lines (V) ranged from 119 mg/100 g fresh weight to 963 mg/100 g fresh weight. HPLC–MS analysis of the anthocyanin fractions of grapes in three selected high-polyphenol lines showed predominantly the glucosides of delphinidin, cyanidin, peonidin, petunidin and malvidin with lesser amounts of acetoyl glucosides and coumaroyl glucosides. Anthocyanin fractionation based on hydrophobicity and subsequent evaluation of antioxidant activities showed varying efficiencies in scavenging superoxide, hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. However, antiproliferative activity of these fractions evaluated using the estrogen receptor positive MCF-7 cells were very similar. High polyphenol grapes and products derived from such grapes may be useful as a concentrated source of dietary polyphenols.