Standard Mobile Phone Research Articles

Mobile User Connectivity in Relay-Assisted Visible Light Communications.

In this paper, we investigate relay-assisted visible light communications (VLC) where a mobile user acts as a relay and forwards data from a transmitter to the end mobile user. We analyse the utilization of the amplify-and-forward (AF) and decode-and-forward (DF) relaying schemes. The focus of the paper is on analysis of the behavior of the mobile user acting as a relay while considering a realistic locations of the receivers and transmitters on a standard mobile phone, more specifically with two photodetectors on both sides of a mobile phone and a transmitting LED array located upright. We also investigate dependency of the bit error rate (BER) performance on the azimuth and elevation angles of the mobile relay device within a typical office environment. We provide a new analytical description of BER for AF and DF-based relays in VLC. In addition we compare AF and DF-based systems and show that DF offers a marginal improvement in the coverage area with a BER < 10–3 and a data rate of 100 Mb/s. Numerical results also illustrate that relay-based systems offer a significant improvement in terms of the coverage compared to direct non-line of sight VLC links.

High mobile phone ownership but low internet access and use among young adults attending an urban HIV clinic in Uganda

ABSTRACTWhilst there is increasing interest in the use of mobile phones and other technologies for improving health outcomes (mHealth), limited data exists on how young people living with HIV use these technologies to gather information and support their health. We sought to assess access and use of mobile phones and the internet among young adults living with HIV attending the Infectious Diseases Institute (IDI) clinic, Kampala. Data collection took place between March 2014 and January 2016 among young adults aged 18–24 years attending the IDI transition clinic in a cross-sectional survey using a semi-structured questionnaire. Of the 272 young adults interviewed, 75% were female and median age was 22.3 years (IQR: 20.6–23.5). Whilst there was a trend to females being more likely to use mobile phones compared to the males, this was not statistically significant (93.7% female versus 85.9%, p = 0.057). Fifty percent of mobile phone users used their phones for HIV-related activities such as medication reminders. General access and use of the internet was low at 34% and users were more likely to be males than females (45.5% versus 30.6%, p = 0.027). A third (32.3%) of the internet users used it to search for HIV-related information. Owning a mobile phone was associated with ease of access to HIV information and preference to receive messages via text messages (p < 0.05). Having internet access was associated with very easy access to HIV information and preference to receive information via email. Despite the rise in smartphones and internet access in Uganda, in this group both access to and use of standard mobile phones are higher than internet-based methods such as email. Using newer technologies to engage with patients especially young people is a great opportunity, but the innovations need to be tailored to the needs and technology access for different patient populations.

Link Budget Maximization for a Mobile-Band Subsurface Wireless Sensor in Challenging Water Utility Environments

A subsurface chamber transceiver system and associated propagation channel link budget considerations for an underground wireless sensor system (UWSS) are presented: the application was a sewerage system for a water utility company. The UWSS operates over the GSM850/900, GSM1800/1900, and Universal Mobile Telecommunications System (UMTS) bands in order to operate with the standard public mobile phone system. A novel antenna was developed to minimize path loss from the underground location: a folded loop type, which is small enough to fit conveniently inside a utility manhole access chamber while giving adequate signal strength to link to mobile base stations from such a challenging environment. The electromagnetic performance was simulated and measured in both free space and in a real manhole chamber. An experimental test bed was created to determine the return loss and received signal strength with different transceiver positions below the manhole chamber access cover. Both numerical and experimental results suggested an optimum position of the unit inside the manhole, combining easy access for maintenance with viable received signal strength. This confirmed that the characteristics were adequate for incorporation in a transceiver designed to communicate with mobile base stations from underground. A field trial confirmed the successful operation of the system under severe conditions.

A novel and independent method for time-resolved gantry angle quality assurance for VMAT.

Volumetric‐modulated arc therapy (VMAT) treatment delivery requires three key dynamic components; gantry rotation, dose rate modulation, and multi‐leaf collimator motion, which are all simultaneously varied during the delivery. Misalignment of the gantry angle can potentially affect clinical outcome due to the steep dose gradients and complex MLC shapes involved. It is essential to develop independent gantry angle quality assurance (QA) appropriate to VMAT that can be performed simultaneously with other key VMAT QA testing. In this work, a simple and inexpensive fully independent gantry angle measurement methodology was developed that allows quantitation of the gantry angle accuracy as a function of time. This method is based on the analysis of video footage of a “Double dot” pattern attached to the front cover of the linear accelerator that consists of red and green circles printed on A4 paper sheet. A standard mobile phone is placed on the couch to record the video footage during gantry rotation. The video file is subsequently analyzed and used to determine the gantry angle from each video frame using the relative position of the two dots. There were two types of validation tests performed including the static mode with manual gantry angle rotation and dynamic mode with three complex test plans. The accuracy was 0.26° ± 0.04° and 0.46° ± 0.31° (mean ± 1 SD) for the static and dynamic modes, respectively. This method is user friendly, cost effective, easy to setup, has high temporal resolution, and can be combined with existing time‐resolved method for QA of MLC and dose rate to form a comprehensive set of procedures for time‐resolved QA of VMAT delivery system.

Improving official statistics in emerging markets using machine learning and mobile phone data

Mobile phones are one of the fastest growing technologies in the developing world with global penetration rates reaching 90%. Mobile phone data, also called CDR, are generated everytime phones are used and recorded by carriers at scale. CDR have generated groundbreaking insights in public health, official statistics, and logistics. However, the fact that most phones in developing countries are prepaid means that the data lacks key information about the user, including gender and other demographic variables. This precludes numerous uses of this data in social science and development economic research. It furthermore severely prevents the development of humanitarian applications such as the use of mobile phone data to target aid towards the most vulnerable groups during crisis. We developed a framework to extract more than 1400 features from standard mobile phone data and used them to predict useful individual characteristics and group estimates. We here present a systematic cross-country study of the applicability of machine learning for dataset augmentation at low cost. We validate our framework by showing how it can be used to reliably predict gender and other information for more than half a million people in two countries. We show how standard machine learning algorithms trained on only 10,000 users are sufficient to predict individual’s gender with an accuracy ranging from 74.3 to 88.4% in a developed country and from 74.5 to 79.7% in a developing country using only metadata. This is significantly higher than previous approaches and, once calibrated, gives highly accurate estimates of gender balance in groups. Performance suffers only marginally if we reduce the training size to 5,000, but significantly decreases in a smaller training set. We finally show that our indicators capture a large range of behavioral traits using factor analysis and that the framework can be used to predict other indicators of vulnerability such as age or socio-economic status. Mobile phone data has a great potential for good and our framework allows this data to be augmented with vulnerability and other information at a fraction of the cost.

Atrial Fibrillation Detection via Accelerometer and Gyroscope of a Smartphone.

We present a smartphone-only solution for the detection of atrial fibrillation (AFib), which utilizes the built-in accelerometer and gyroscope sensors [inertial measurement unit, (IMU)] in the detection. Depending on the patient's situation, it is possible to use the developed smartphone application either regularly or occasionally for making a measurement of the subject. The smartphone is placed on the chest of the patient who is adviced to lay down and perform a noninvasive recording, while no external sensors are needed. After that, the application determines whether the patient suffers from AFib or not. The presented method has high potential to detect paroxysmal ("silent") AFib from large masses. In this paper, we present the preprocessing, feature extraction, feature analysis, and classification results of the envisioned AFib detection system based on clinical data acquired with a standard mobile phone equipped with Google Android OS. Test data was gathered from 16 AFib patients (validated against ECG), as well as a control group of 23 healthy individuals with no diagnosed heart diseases. We obtained an accuracy of 97.4% in AFib versus healthy classification (a sensitivity of 93.8% and a specificity of 100%). Due to the wide availability of smart devices/sensors with embedded IMU, the proposed methods could potentially also scale to other domains such as embedded body-sensor networks.

Evaluation of Children’s Exposure to Electromagnetic Fields of Mobile Phones Using Age-Specific Head Models With Age-Dependent Dielectric Properties

Given the rapid introduction of mobile phones and other portable wireless devices into society, and the increased possibility of young children using or being exposed to electromagnetic (EM) fields, a study of specific absorption rate (SAR) in the head of young children is becoming increasingly relevant. To accurately evaluate the exposure of children to electromagnetic fields, realistic head models, which consider the age-specific anatomical structure and age-dependent tissues dielectric properties, are developed. During postnatal development of human tissues, the number and size of cells increase while the proportion of water content decreases. Such changes result generally in significant changes in the dielectric properties of tissues. The SAR levels for different ages are investigated using the developed children’s head models when young children or their parents use a standard mobile phone. The results show that the maximum SAR levels in brain tissues of young children (3 months) are higher by up to 61% and 78% than adults at the lowest (700 MHz) and highest (2600 MHz) investigated frequencies, respectively. The percentage absorption power in the heads of young children (3 months) is higher by up to 40.6% and 24% than the values for adults at 700 MHz and 2600 MHz, respectively. Our investigation shows that previous studies, which used scaled head models without considering the age-dependent variations in the head anatomy and/or age-dependent tissues’ dielectric properties, underestimated SAR levels in the children’s heads. The obtained results using the developed realistic head models indicate that for young children, a lower limit on radiated power might be required to meet the acceptable dosimetry levels.

Wearable dry sensors with bluetooth connection for use in remote patient monitoring systems.

Cost reduction has become the primary theme of healthcare reforms globally. More providers are moving towards remote patient monitoring, which reduces the length of hospital stays and frees up their physicians and nurses for acute cases and helps them to tackle staff shortages. Physiological sensors are commonly used in many human specialties e.g. electrocardiogram (ECG) electrodes, for monitoring heart signals, and electroencephalogram (EEG) electrodes, for sensing the electrical activity of the brain, are the most well-known applications. Consequently there is a substantial unmet need for physiological sensors that can be simply and easily applied by the patient or primary carer, are comfortable to wear, can accurately sense parameters over long periods of time and can be connected to data recording systems using Bluetooth technology. We have developed a small, battery powered, user customizable portable monitor. This prototype is capable of recording three-axial body acceleration, skin temperature, and has up to four bio analogical front ends. Moreover, it is also able of continuous wireless transmission to any Bluetooth device including a PDA or a cellular phone. The bio-front end can use long-lasting dry electrodes or novel textile electrodes that can be embedded in clothes. The device can be powered by a standard mobile phone which has a Ni-MH 3.6 V battery, to sustain more than seven days continuous functioning when using the Bluetooth Sniff mode to reduce TX power. In this paper, we present some of the evaluation experiments of our wearable personal monitor device with a focus on ECG applications.

Reading Out Single-Molecule Digital RNA and DNA Isothermal Amplification in Nanoliter Volumes with Unmodified Camera Phones.

Digital single-molecule technologies are expanding diagnostic capabilities, enabling the ultrasensitive quantification of targets, such as viral load in HIV and hepatitis C infections, by directly counting single molecules. Replacing fluorescent readout with a robust visual readout that can be captured by any unmodified cell phone camera will facilitate the global distribution of diagnostic tests, including in limited-resource settings where the need is greatest. This paper describes a methodology for developing a visual readout system for digital single-molecule amplification of RNA and DNA by (i) selecting colorimetric amplification-indicator dyes that are compatible with the spectral sensitivity of standard mobile phones, and (ii) identifying an optimal ratiometric image-process for a selected dye to achieve a readout that is robust to lighting conditions and camera hardware and provides unambiguous quantitative results, even for colorblind users. We also include an analysis of the limitations of this methodology, and provide a microfluidic approach that can be applied to expand dynamic range and improve reaction performance, allowing ultrasensitive, quantitative measurements at volumes as low as 5 nL. We validate this methodology using SlipChip-based digital single-molecule isothermal amplification with λDNA as a model and hepatitis C viral RNA as a clinically relevant target. The innovative combination of isothermal amplification chemistry in the presence of a judiciously chosen indicator dye and ratiometric image processing with SlipChip technology allowed the sequence-specific visual readout of single nucleic acid molecules in nanoliter volumes with an unmodified cell phone camera. When paired with devices that integrate sample preparation and nucleic acid amplification, this hardware-agnostic approach will increase the affordability and the distribution of quantitative diagnostic and environmental tests.

塗装表面微細凹凸の画像照合による工業製品の個品認証

Production, distribution and use of industrial products are globalized, and ensuring traceability and anti-counterfeit become serious problems for quality management and user service. In this paper, we propose a novel method for machinery identification without using tag. First, it is discovered experimentally that micro-bumps generated by widely-used paint contain sufficiently unique features in only 1cm2 area, and the features enable identification with Equal Error Rate (EER) of less than 10-8. Since the features are naturally created during manufacture, they can take the place of costly tags or marking for identification and anti-counterfeit. Next, a new practical method is proposed to use a standard mobile phone camera and a LED line illumination for capturing features of the painted surface. The identification accuracy is evaluated in the real industrial factory environments. 672 images of 112 individuals of the actual machinery products were perfectly identified.

A study of mobile phone use among patients with noncommunicable diseases in La Paz, Bolivia: implications for mHealth research and development.

BackgroundWhile global momentum supporting mobile health (mHealth) research and development is increasing, it is imperative to assess the potential fit of mHealth programs in local settings. We describe the penetration of mobile technologies among Bolivian patients with noncommunicable diseases (NCDs) to inform research on mHealth interventions for the Andean region as well as low- and middle-income countries more generally.MethodsFive-hundred and fifty-nine NCD patients were identified from outpatient clinics affiliated with four hospitals in the cities of La Paz and El Alto. Respondents completed surveys about their use of standard mobile phones and smartphones. Respondents also provided information about their sociodemographic characteristics, health status, and access to care. We used descriptive statistics and logistic regression to understand the variation in mobile phone use across groups defined by patient characteristics associated with health service access and socioeconomic vulnerability.ResultsRespondents were on average 52 years of age, 33 % had at most a sixth grade education, and 30 % spoke an indigenous language in their home. Eighty-six percent owned a mobile phone and 13 % owned a smartphone. Fifty-eight percent of mobile phone users sent or received a text message at least once a week. Some mobile phone owners reported connectivity problems, such as lacking mobile signal (9 %) or credit to make a call (17 %). Younger age, male gender, high health literacy, more years of education, and having fewer previously diagnosed NCDs were positively related to mobile phone ownership. Among mobile phone users, respondents with lower education and other indicators of vulnerability were less likely than their counterparts to report frequent usage of texting services.ConclusionsMobile phones have high penetration among NCD patients in La Paz, Bolivia, including among those who are older, less educated, and who have other socioeconomic risk factors. Smartphone use is still relatively uncommon, even among patients who are younger and more educated. While certain patient characteristics such as age or education impact patients’ use of text messaging, mobile phone-based mHealth interventions are feasible strategies for increasing NCD patients’ access to self-management support between face-to-face clinical encounters.

Face recognition from a single registered image for conference socializing

Scientific conferences are primary venues for connecting with and forming relationships with fellow researchers and scientists. Thus, over the course of a conference participants often take advantage of the many opportunities to network. In this setting, it is desirable to quickly recognize the identity of the persons we see and wish to meet. In particular, it could be embarrassing to not recognize a prominent researcher. In this paper, we investigate a novel face recognition framework that is applicable to conference socialization scenarios. In the proposed framework, only frontal images are used as training images; and face recognition is possible from an arbitrary view of a subject. Our system prototype assumes that the conference participants have uploaded a frontal photo during the registration process. At the conference, the identity of a person can be recognized from a picture, taken from an arbitrary angle with a standard mobile phone. Our experimental results indicate that the proposed framework is robust to possible large pose variations between the non-frontal image captured impromptu and the training image of the same person. Experiments based upon standard face dataset and real conference socializing datasets are conducted to test the effectiveness of the proposed techniques.

Medicolegal X-Ray and CT of standard size mobile phone cards (SIM card)

Background. Foreign body ingestion typically affects children or adults with mental conditions. SIM (subscriber identity module) card ingestion is extremely rare. As their particularly X-Ray dense metal parts are sized about 9 � 12 mm � 50−−80 μ, they can be difficult to capture on plain radiographs. We were asked by investigative authorities to point out the best method to document intentionally swallowed SIM cards. Method and material. A case of a 23 year old female who had swallowed a SIM card when she was arrested for murder was followed up with four abdomen radiographs and CT (computed tomography) of the abdomen. Experimentally, SIM cards were examined in CT. SIM card object contrast against surrounding background was quantified through CNR (contrast-to-noise ratio). Results. SIM card orientation perpendicular to plain film X-Ray beams resulted in relatively low CNR values of 1.6–2.5. SIM cards in CT scans yielded considerably better CNR values exceeding 9. Discussion. While plain abdomen radiographs have a lower X-Ray dose than abdomen CT scans, more frequent possibly negative results may lead to repetitive exposure. We recommend to consider drug trafficking as possible problem in conjunction with any observed SIM card swallowing, particularly in context of police arrests or a suspect's detention. We recommend to consider CT of the abdomen, if possible with a low dose, rather than plain abdomen radiographs. & 2013 Elsevier Ltd. All rights reserved.

Mobile health use in low- and high-income countries: an overview of the peer-reviewed literature

The evolution of mobile phone technology has introduced new possibilities to the field of medicine. Combining technological advances with medical expertise has led to the use of mobile phones in all healthcare areas including diagnostics, telemedicine, research, reference libraries and interventions. This article provides an overview of the peer-reviewed literature, published between 1 August 2006 and 1 August 2011, for the application of mobile/cell phones (from basic text-messaging systems to smartphones) in healthcare in both resource-poor and high-income countries. Smartphone use is paving the way in high-income countries, while basic text-messaging systems of standard mobile phones are proving to be of value in low- and middle-income countries. Ranging from infection outbreak reporting, anti-HIV therapy adherence to gait analysis, resuscitation training and radiological imaging, the current uses and future possibilities of mobile phone technology in healthcare are endless. Multiple mobile phone based applications are available for healthcare workers and healthcare consumers; however, the absolute majority lack an evidence base. Therefore, more rigorous research is required to ensure that healthcare is not flooded with non-evidence based applications and is maximized for patient benefit.

ISO 14443A active load modulation technology and its integration in the micro-SD card form factor

A more detailed analysis of the market for mobile phones shows that the proportion of Near Field Communication (NFC)-enabled devices for contactless mobile payment in comparison to the total number of non-NFCenabled mobile phones has grown very slowly. It is predicted that approximately 1.3 billion mobile phones will be sold in 2011 but only a very small proportion with NFC interface equipment. Mobile phone manufacturers are hesitant to implement NFC technology (ISO\IEC 14443/13.56 MHz band) into their mobile phones as there is a lack of mobile payment applications and a small payment infrastructure with point of sales terminals. As a result, a typical ‘chicken or egg’ causality dilemma currently exists in this field. In order to make a breakthrough for mobile payment applications, a far greater share of NFC capable handsets is required. One possible way to solve this dilemma can be to use a standard mobile phone with a replaceable memory device (micro-SD card) including active load modulation for ISO\IEC 14443 type A. In this paper the active load modulation technique and the integration in the micro-SD form factor are described.

Manufacture and performance evaluation of solar garment

Abstract This study proposes a method for solar garment manufacture based on human comfort, which aims to address current energy shortage and excessive pollutants emission in the environment. Moreover, the performance of the garment power storage is tested and evaluated. Flexible solar materials are placed in the back part of the garment, and a circuit is also sewed. The garment accumulates solar energy, which is then transformed into electric energy for power supply. The power storage performance of solar garment is then tested under different unsteady environments. This study concludes that the solar garment can absorb solar energy and save electric energy within 2–3 h under sunny weather condition, and consequently fully charge a standard Nokia mobile phone with 3.7 V/720 mAh in 1.75 h. Results of experiments and analyses show that the solar garment can supply electric energy to a number of portable electronic devices, such as a mobile phone, MP3 player, and shaver. The solar garment also provides convenience, practicality, and comfort. The solar garment not only has good economic and application prospects but also provides a new method for the effective utilization of clean energy, which is significant for energy conservation and environmental protection.

Useful and easy-to-use interactive voice for emergency data exchange

Purpose – Telephone calls are the predominant telecommunication mode in Sri Lanka. Consequently, leveraging voice-based applications for disaster communication would be acceptable and sustainable. The purpose of this paper is to realise the design requirements for an integrated voice-enabled alerting and reporting system, and then to use the lessons learned to influence disaster management researchers, practitioners and developers to invest resources in related new system developments. Design/methodology/approach – The findings in this paper are from an experiment concerning interactive voice for connecting community-based emergency field operatives with their central co-ordination hub. Findings – A particular challenge was in interchanging Sinhala and Tamil language speech data, generated by the Freedom Fone Interactive Voice Response, with the text-based “Sahana” disaster-management system for analysis and decision support. The Emergency Data Exchange Language interoperable content standard was adopted for mediation between the two disparate systems. Standard mobile phones were the interface linking the Community Emergency Response Team (CERT) members. Low quality voice transmissions over the GSM cellular infrastructure resulted in distorted data. This shortcoming was a barrier to automating transformations between text and speech. Originality/value – Replacing those processes with human procedure significantly degrades their reliability. Nevertheless, the CERT members find voice-enabled information exchange useful and easy to use, because it diminishes the need for computer literacy and removes language barriers. The paper discusses the utility evaluation of the introduced system.

Close Loop Feedback System for Device Automation

The short message system (SMS) of a standard mobile phone can be used for much more than just exchanging cryptic message. This application uses a mobile for a remote site monitoring and controlling external equipments. The SMS service provided by the service providers are comparatively low cost. Hence a highly efficient and low cost system can be implemented for a variety of industrial applications to control the status of the devices as well as monitor their status periodically.

Instructional Videocasts: Facilitating Learning in a Mobile World

This paper critically discusses the new opportunities unique to the use of mobile platforms to complement formal learning with informal learning in an apprenticeship context. It begins with an outline of a problem identified by the teacher-researcher with phase six apprentice bricklaying students achieving psychomotor learning outcomes, mainly due to high student numbers and limited available workshop time. A solution to this problem is presented through the facilitation of the students using eleven short instructional video demonstrations on mobile phones to optimise their time. These were uploaded to the memory cards of the students’ mobile phones. Within an action research approach, data was collected from sixteen students using a combination of a survey, a practical assessment, a focus group interview, and through keeping a research diary. The study showed all of the students were in favour of using their mobile phones for just-in-time training and more than 90% wanted to utilise this method of learning on their work sites in the future. Ninety five percent (95%) found the picture quality of the videos good on their standard mobile phones and had experienced limited technical difficulties. Most importantly, the study showed that the use of mLearning was more effective in enabling apprentice students to achieve practical learning outcomes than the previous face-to-face training alone.Read More: http://journals.heacademy.ac.uk/doi/abs/10.11120/tran.2011.08020004

P2P Multiuser Low-Cost Universal Solution for On-Demand GPS Positioning and Tracking in Large Environments

This paper presents the design and development of an on-demand low-cost positioning and tracking (P&T) system for large environments based on standard mobile phones and Global Positioning System (GPS)-enabled devices, which allows the position of a terminal to be tracked by exchanging text or multimedia messages using short message service (SMS) and/or multimedia message service (MMS). In contrast with other works in the state of the art, the presented method and system do not require an intermediate server or an intermediation center (location-based service (LBS) providers) since communication is performed, following a peer-to-peer (P2P) paradigm. The P2P communication established between two devices with means of access to the mobile network is carried out, guaranteeing the privacy, security, and anonymity in their use and avoiding third-party intervention. Moreover, the proposed procedure protects the user from unwanted tracking through exchange of specific information, following a predefined protocol. In addition, the confidentiality of the information exchanged is guaranteed, in part, by the underlying wireless communication protocols that encrypt the messages swapped. The presented method and system represent an improvement with respect to the state-of-the-art P&T devices since it runs on standard mobile platforms, avoiding the need for a specific hardware and guaranteeing the universalization of the service. Another major advantage with respect to existing devices is that one peer can track multiple users, and each user can be tracked by multiple peers with no third-party intervention.