Fibre Bragg grating sensors for distributive tactile sensing

Distributive tactile sensing is a method of tactile sensing in which a small number of sensors monitors the behaviour of a flexible substrate which is in contact with the object being sensed. This paper describes the first use of fibre Bragg grating sensors in such a system. Two systems are presented: the first is a one-dimensional metal strip with an array of four sensors, which is capable of detecting the magnitude and position of a contacting load. This system is favourably compared experimentally with a similar system using resistive strain gauges. The second system is a two-dimensional steel plate with nine sensors which is able to distinguish the position and shape of a contacting load, or the positions of two loads simultaneously. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact. Issues and limitations of the systems are discussed, along with proposed solutions to some of the difficulties. © 2007 IOP Publishing Ltd.

Fluctuations and correlations in sandpiles and interfaces with boundary pinning

Interfaces are studied in an inhomogeneous critical state where boundary pinning is compensated with a ramped force. Sandpiles driven off the self-organized critical point provide an example of this ensemble in the Edwards-Wilkinson (EW) model of kinetic roughening. A crossover from quenched to thermal noise violates spatial and temporal translational invariances. The bulk temporal correlation functions have the effective exponents β1D∼0.88±0.03 and β2D∼0.52±0.05, while at the boundaries βb,1D/2D∼0.47±0.05. The bulk β1D is shown to be reproduced in a randomly kicked thermal EW model.

Fluctuations and correlations in sandpiles and interfaces with boundary pinning

Interfaces are studied in an inhomogeneous critical state where boundary pinning is compensated with a ramped force. Sandpiles driven off the self-organized critical point provide an example of this ensemble in the Edwards-Wilkinson (EW) model of kinetic roughening. A crossover from quenched to thermal noise violates spatial and temporal translational invariances. The bulk temporal correlation functions have the effective exponents β1D∼0.88±0.03 and β2D∼0.52±0.05, while at the boundaries βb,1D/2D∼0.47±0.05. The bulk β1D is shown to be reproduced in a randomly kicked thermal EW model.

Flexible tactile digital feedback for clinical applications

Trauma and damage to the delicate structures of the inner ear frequently occurs during insertion of electrode array into the cochlea. This is strongly related to the excessive manual insertion force of the surgeon without any tool/tissue interaction feedback. The research is examined tool-tissue interaction of large prototype scale (12.5:1) digit embedded with distributive tactile sensor based upon cochlear electrode and large prototype scale (4.5:1) cochlea phantom for simulating the human cochlear which could lead to small scale digit requirements. This flexible digit classified the tactile information from the digit-phantom interaction such as contact status, tip penetration, obstacles, relative shape and location, contact orientation and multiple contacts. The digit, distributive tactile sensors embedded with silicon-substrate is inserted into the cochlea phantom to measure any digit/phantom interaction and position of the digit in order to minimize tissue and trauma damage during the electrode cochlear insertion. The digit is pre-curved in cochlea shape so that the digit better conforms to the shape of the scala tympani to lightly hug the modiolar wall of a scala. The digit have provided information on the characteristics of touch, digit-phantom interaction during the digit insertion. The tests demonstrated that even devices of such a relative simple design with low cost have potential to improve cochlear implants surgery and other lumen mapping applications by providing tactile feedback information by controlling the insertion through sensing and control of the tip of the implant during the insertion. In that approach, the surgeon could minimize the tissue damage and potential damage to the delicate structures within the cochlear caused by current manual electrode insertion of the cochlear implantation. This approach also can be applied diagnosis and path navigation procedures. The digit is a large scale stage and could be miniaturized in future to include more realistic surgical procedures.

Power electronic interfaces for low voltage residential networks

A proposal to increase the existing residential LV grid voltage from 230 V to 300 V has been made in order to increase existing network capacity. A power-electronic AC-AC converter is then used to provide 230 V at each property. The equipment can also provide power-quality improvements to the network and load. Several constraints such as temperature rise at the converter location lead to a converter design requiring very high efficiency. In this paper different AC/AC converter topologies are presented which compares the power quality benefits, size and efficiency of each converter. The design and the control technique of the most suitable topology are verified using simulation and preliminary experimentally results of prototype hardware are also included. © 2013 IEEE.

An optical fiber Bragg grating tactile sensor

Tactile sensors are needed for many emerging robotic and telepresence applications such as keyhole surgery and robot operation in unstructured environments. We have proposed and demonstrated a tactile sensor consisting of a fibre Bragg grating embedded in a polymer "finger". When the sensor is placed in contact with a surface and translated tangentially across it measurements on the changes in the reflectivity spectrum of the grating provide a measurement of the spatial distribution of forces perpendicular to the surface and thus, through the elasticity of the polymer material, to the surface roughness. Using a sensor fabricated from a Poly Siloxane polymer (Methyl Vinyl Silicone rubber) spherical cap 50 mm in diameter, 6 mm deep with an embedded 10 mm long Bragg grating we have characterised the first and second moment of the grating spectral response when scanned across triangular and semicircular periodic structures both with a modulation depth of 1 mm and a period of 2 mm. The results clearly distinguish the periodicity of the surface structure and the differences between the two different surface profiles. For the triangular structure a central wavelength modulation of 4 pm is observed and includes a fourth harmonic component, the spectral width is modulated by 25 pm. Although crude in comparison to human senses these results clearly shown the potential of such a sensor for tactile imaging and we expect that with further development in optimising both the grating and polymer "finger" properties a much increased sensitivity and spatial resolution is achievable.

Distributive tactile sensing using fibre Bragg grating sensors for biomedical applications

Artificial tactile sensing systems using the distributive tactile sensing technique and fibre Bragg grating sensors are presented. A one-dimensional arrangement, with possible applications in an endoscope, is compared with a similar arrangement using conventional electronic sensors. A two-dimensional sensing surface is described, with potential applications in human balance and gait analysis, capable of detecting simultaneously the position and shape of an object placed upon it. It is believed that this work represents the first use of fibre Bragg grating sensors in a distributive sensing regime.

Distributive tactile sensing using fibre bragg grating sensors

Two distributive tactile sensing systems are presented, based on fibre Bragg grating sensors. The first is a one-dimensional metal strip with an array of 4 sensors, which is capable of detecting the magnitude and position of a contacting load. This system is compared experimentally with a similar system using resistive strain gauges. The second is a two-dimensional steel plate with 9 sensors which is able to distinguish the position and shape of a contacting load. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact.

Involvement of tissue transglutaminase in the stabilisation of biomaterial/tissue interfaces important in medical devices

Tissue transglutaminase (tTG) has recently been established as a novel cell surface adhesion protein that binds with high affinity to fibronectin in the pericellular matrix. In this study, we have made use of this property to enhance the biocompatibility of poly(epsilon-caprolactone) (PCL), a biomaterial currently used in bone repair. Poly(epsilon-caprolactone) discs were first coated with fibronectin and then tTG. The surface localisation of the two proteins was confirmed using ELISA and the tTG shown to be active on the surface by incorporation of biotin cadaverine into the fibronectin coating. When human osteoblasts (HOBs) were seeded onto the coated polymer surfaces in serum free medium, the surface coated with fibronectin and then tTG showed an increase in the spreading of the cells as compared to the surface coated with fibronectin alone, when analysed using environmental scanning electron microscopy. The presence of tTG had no effect on HOB cell differentiation when analysed by determining alkaline phosphatase activity. The use of tTG as a novel adhesion protein in this way may therefore have considerable potential in forming a stable tissue/biomaterial interface for application in medical devices.

Web Interfaces Destined for People with Disabilities

One of the main characteristics of the world that we live in is the access to information and one of the main ways to reach the information is the Internet. Most Internet sites put accessibility problem on a secondary plan. If we try to define this concept (accessibility) we could say that accessibility it’s a way to offer access to information for the people with disabilities. For example blind people can’t navigate on the Internet like usual people. For that reason Internet sites have to put at their disposal ways to make their content known to this people. Accessibility does not refer only at blind people the web accessibility refers to all people who lost their ability to access the Internet sites. The web accessibility includes every disability that stops people with disabilities to access the web sites content like hearing disability, neurological and cognitive. People that have low speed Internet connection or with low performance computers can use the web accessibility.

Comparing interaction techniques for serious games through brain-computer interfaces:a user perception evaluation study

This paper examines the application of commercial and non-invasive electroencephalography (EEG)-based brain-computer (BCIs) interfaces with serious games. Two different EEG-based BCI devices were used to fully control the same serious game. The first device (NeuroSky MindSet) uses only a single dry electrode and requires no calibration. The second device (Emotiv EPOC) uses 14 wet sensors requiring additional training of a classifier. User testing was performed on both devices with sixty-two participants measuring the player experience as well as key aspects of serious games, primarily learnability, satisfaction, performance and effort. Recorded feedback indicates that the current state of BCIs can be used in the future as alternative game interfaces after familiarisation and in some cases calibration. Comparative analysis showed significant differences between the two devices. The first device provides more satisfaction to the players whereas the second device is more effective in terms of adaptation and interaction with the serious game.

Re-imagining commonly used mobile interfaces for older adults

Many countries have an increasingly ageing population. In recent years, mobile technologies have had a massive impact on social and working lives. As the size of the older user population rises, many people will want to continue professional, social and lifestyle usage of mobiles into 70s and beyond. Mobile technologies can lead to increased community involvement and personal independence. While mobile technologies can provide many opportunities, the ageing process can interfere with their use. This workshop brings together researchers who are re-imagining common mobile interfaces so that they are more suited to use by older adults.

Orthogonal frequency division multiplexing based air interfaces and multiple input multiple output techniques in cooperative satellite communications for 4th generation mobile systems

Recently, wireless network technology has grown at such a pace that scientific research has become a practical reality in a very short time span. Mobile wireless communications have witnessed the adoption of several generations, each of them complementing and improving the former. One mobile system that features high data rates and open network architecture is 4G. Currently, the research community and industry, in the field of wireless networks, are working on possible choices for solutions in the 4G system. 4G is a collection of technologies and standards that will allow a range of ubiquitous computing and wireless communication architectures. The researcher considers one of the most important characteristics of future 4G mobile systems the ability to guarantee reliable communications from 100 Mbps, in high mobility links, to as high as 1 Gbps for low mobility users, in addition to high efficiency in the spectrum usage. On mobile wireless communications networks, one important factor is the coverage of large geographical areas. In 4G systems, a hybrid satellite/terrestrial network is crucial to providing users with coverage wherever needed. Subscribers thus require a reliable satellite link to access their services when they are in remote locations, where a terrestrial infrastructure is unavailable. Thus, they must rely upon satellite coverage. Good modulation and access technique are also required in order to transmit high data rates over satellite links to mobile users. This technique must adapt to the characteristics of the satellite channel and also be efficient in the use of allocated bandwidth. Satellite links are fading channels, when used by mobile users. Some measures designed to approach these fading environments make use of: (1) spatial diversity (two receive antenna configuration); (2) time diversity (channel interleaver/spreading techniques); and (3) upper layer FEC. The author proposes the use of OFDM (Orthogonal Frequency Multiple Access) for the satellite link by increasing the time diversity. This technique will allow for an increase of the data rate, as primarily required by multimedia applications, and will also optimally use the available bandwidth. In addition, this dissertation approaches the use of Cooperative Satellite Communications for hybrid satellite/terrestrial networks. By using this technique, the satellite coverage can be extended to areas where there is no direct link to the satellite. For this purpose, a good channel model is necessary.

Orthogonal Frequency Division Multiplexing Based Air Interfaces and Multiple Input Multiple Output Techniques in Cooperative Satellite Communications for 4th Generation Mobile Systems

Recently, wireless network technology has grown at such a pace that scientific research has become a practical reality in a very short time span. One mobile system that features high data rates and open network architecture is 4G. Currently, the research community and industry, in the field of wireless networks, are working on possible choices for solutions in the 4G system. The researcher considers one of the most important characteristics of future 4G mobile systems the ability to guarantee reliable communications at high data rates, in addition to high efficiency in the spectrum usage. On mobile wireless communication networks, one important factor is the coverage of large geographical areas. In 4G systems, a hybrid satellite/terrestrial network is crucial to providing users with coverage wherever needed. Subscribers thus require a reliable satellite link to access their services when they are in remote locations where a terrestrial infrastructure is unavailable. The results show that good modulation and access technique are also required in order to transmit high data rates over satellite links to mobile users. The dissertation proposes the use of OFDM (Orthogonal Frequency Multiple Access) for the satellite link by increasing the time diversity. This technique will allow for an increase of the data rate, as primarily required by multimedia applications, and will also optimally use the available bandwidth. In addition, this dissertation approaches the use of Cooperative Satellite Communications for hybrid satellite/terrestrial networks. By using this technique, the satellite coverage can be extended to areas where there is no direct link to the satellite. The issue of Cooperative Satellite Communications is solved through a new algorithm that forwards the received data from the fixed node to the mobile node. This algorithm is very efficient because it does not allow unnecessary transmissions and is based on signal to noise ratio (SNR) measures.

Semantikos: proposta de interfaces para aplicativo mediador de técnica de diferencial semântico em mobile tablet

This research aims to systematize a proposal of developing a mobile tablet application in order to help implementing the Semantic Differential technique – SD, under the approach of Participatory Design. In 1975, Osgood et al. created the Semantic Differential technique. Since then, many experiments use it to measure the affective perception of individuals concerning objects and concepts by means of compounded scales of bipolar adjectives, based on the theoretical models that support the technique: the conductible, spatial and metric models. During the application of the technique with potential users, the researcher must simultaneously manage several contexts, that is, audio recorder, when authorized, and observe and record spontaneous reports of the respondent. It is noticeable that often occurs a cognitive overload during this event. Thus, the use of a single application whose interface is assigned to its users and respondents could assist researchers in applying the SD technique. This research aimed to understand the processes inherent to the task of implementing the Semantic Differential technique and obeyed the following steps: a) training of users, b) background questionnaire c) interview with Focus Group, and d) cooperative evaluation. Besides these procedures, one can also observe the degrees of facilitation or difficulty concerning the use of the conventional model, which is the development and application of scales with the aid of printed material, pencil, pens, clipboards, and recorder software for editing the document and data analysis. This paper comprises reactions and impressions from the experiences of users of SD technique. Considering the data recollected from the user’s observation, the hypothesis of the experiment proved to be right. It means that the development of the application for mobile tablet employing the technique of Semantic Differential is viable, since it assembles all the steps in one only tool, increases the accomplishment of the task between user/researcher and user/respondent resulting in their mutual satisfaction.