Cellular Phone Communication Research Articles

A FIELD IMAGE MONITORING SYSTEM BASED ON EMBEDDED LINUX

Demands for real-time field monitoring systems are increasing in order to pass good agricultural cultivation practices down to future generations. In this study, a low cost and robust field image monitoring system was developed for acquiring real-time conditions from remote sites. The system consists of inexpensive commercial USB devices and an embedded Linux based broadband router equipped with some USB ports. A 3G USB modem dongle and data communication were used to access the Internet. The total cost of the system was almost 300 US dollars. Field experiments showed that this system met most of the requirements for field image monitoring in agriculture. In our research, the field image monitoring system was built using a WL-500gP v1 with a USB port as a CPU board, using embedded Linux and various USB devices. As a result of field experiments in which this system was installed outdoors, it was possible to demonstrate that it can withstand even high- temperature conditions, in which the interior of the system enclosure reaches 50 °C, as was the case during the 6-month installation period which included the summer. In addition, this system can connect to the network using cellular phone communication even in an area as a field where a wired network connection cannot be used. That is a gateway of the network in the field.

A dual‐band antenna for extending cellular coverage by using energy‐harvesting strategy

AbstractThe widespread use of sensor nodes forces a straightforward, low‐cost, and easy‐to‐implement design of these nodes. Instead of using separate batteries and antennas, this letter proposes a dual‐band microstrip antenna for both communication and energy‐harvesting applications. The energy required for the sensor node is harvested from the broadcast television band and then used in the cellular phone communication band. A previous design of a circular polarized broadband patch antenna is adapted and optimized for the defined requirements with the electromagnetic simulation software CST Studio Suite. The simulations helped in an antenna design with a reflection coefficient below −10 dB in the 600 MHz ‐ 700 MHz television frequency band for the energy harvesting. Furthermore, the antenna is also able to operate in the 850 MHz cellular mobile phone communication band, in order to provide coverage in shadowed remote areas or even to be of use for the transmission of the sensor data. The final design is prototyped and then characterized through the measurement of the reflection coefficient.

Comparison of electromagnetic shielding effectiveness of conductive single jersey fabrics with coaxial transmission line and free space measurement techniques

The aim of this study is to investigate the electromagnetic shielding effectiveness (EMSE) of thin and lightweight knitted fabrics that are suitable for casual wear like t-shirts. For the purpose of having a low production cost, metal/cotton conductive composite yarns are produced by a yarn doubling technique, involving stainless steel wires (35 μm, 50 μm) or copper wires (50 μm, 70 μm) and Ne30/1, Ne40/1, Ne60/2, Ne80/2 count cotton yarns. Single jersey fabrics are knitted on an E20 circular knitting machine with the same machine settings. Coaxial transmission line and free space measurement (by using an anechoic chamber) techniques are used for the EMSE measurements in the frequency range of 100 MHz–1.5 GHz and 1 GHz–18 GHz respectively. The free space measurement technique test results reveal that single jersey knitted fabrics have EMSE ability for the electric field polarization in the same direction as the main direction of the conductive metal wires in the fabric. It is observed that all single jersey fabric structures have more than 7 dB (80% or better) EMSE for GSM-850 and GSM-900 cellular phone communication bands according to coaxial transmission line equipment test results. SNK test results of both test methods reveal that, while 100% cotton fabrics do not have EMSE ability, cotton yarn count is highly significant on the EMSE of single jersey fabrics with conductive composite yarns. Fabrics with two-ply fine cotton yarns (Ne60/2 and Ne80/2) have higher EMSE values than the fabrics with one-ply cotton yarn of the same yarn count (Ne30/1 and Ne40/1).

The Wired Generation: Academic and Social Outcomes of Electronic Media Use Among University Students

Little is known about the influence of electronic media use on the academic and social lives of university students. Using time-diary and survey data, we explore the use of various types of electronic media among first-year students. Time-diary results suggest that the majority of students use electronic media to multitask. Robust regression results indicate a negative relationship between the use of various types of electronic media and first-semester grades. In addition, we find a positive association between social-networking-site use, cellular-phone communication, and face-to-face social interaction.

Lack of Adverse Effects of Whole-Body Exposure to a Mobile Telecommunication Electromagnetic Field on the Rat Fetus

Abstract The recent steep increase in the number of users of cellular phones is resulting in marked increase of exposure of humans to radiofrequency electromagnetic fields (EMFs). Children are of particular concern. Our goal was to evaluate potential adverse effects of long-term whole-body exposure to EMFs simulating those from base stations for cellular phone communication. Pregnant rats were given low, high or no exposure. At the high level, the average specific absorption rate (SAR)for the dams was 0.066-0.093 W/kg. The SAR for the fetuses and the F(1) progeny was 0.068-0.146 W/kg. At the low level, the SARs were about 43% of these. The 2.14 GHz signals were applied for 20 h per day during the gestation and lactation periods. No abnormal findings were observed in either the dams or the F(1) generation exposed to the EMF or in the F(2) offspring. Parameters evaluated included growth, gestational condition and organ weights for dams and survival rates, development, growth, physical and functional development, hormonal status, memory function and reproductive ability of the F(1) offspring (at 10 weeks of age) along with embryotoxicity and teratogenicity in the F(2) rats. Thus, under our experimental conditions, whole-body exposure to 2.14 GHz for 20 h per day during gestation and lactation did not cause any adverse effects on pregnancy or the development of rats.

Cellular phone communication and alexithymia - results of the Radep study

Cellular phone communication and alexithymia - results of the Radep study

Proliferation and apoptosis in a neuroblastoma cell line exposed to 900 MHz modulated radiofrequency field

The aim of this study was to examine whether a modulated radiofrequency of the type used in cellular phone communications at a specific absorption rate (SAR) higher than International Commission on Non-ionizing Radiation Protection (ICNIRP) reference level for occupational exposure, could elicit alterations on proliferation, differentiation, and apoptosis processes in a neuroblastoma cell line. The cell line was exposed for 24, 48, and 72 h to 900 MHz radiofrequency and proliferation and differentiation were tested by WST-I assay and by a molecular analysis of specific markers, two oncogenes and a cytoskeleton protein, in exponential growth phase and in synchronized cell cultures. Apoptosis was evaluated by caspase activation analysis and by molecular detection of Poly (ADP-ribose) polimerase (PARP) cleavage. Combined exposures to radiofrequency and to the differentiative agent retinoic acid or to the apoptotic inducer camptothecin were carried out to test possible interference between electromagnetic field and chemical agents. Overall our data suggest that 900 MHz radiofrequency exposure up to 72 h does not induce significant alterations in the three principal cell activities in a neuroblastoma cell line.

Communication technology in trauma centers: A national survey

The relationship between information and communication technology (ICT) and trauma work coordination has long been recognized. The purpose of the study was to investigate the type and frequency of use of various ICTs to activate and organize trauma teams in level I/II trauma centers. In a cross-sectional survey, questionnaires were mailed to trauma directors and clinicians in 457 trauma centers in the United States. Responses were received from 254 directors and 767 clinicians. Communication with pre-hospital care providers was conducted predominantly via shortwave radio (67.3%). The primary communication methods used to reach trauma surgeons were manual (56.7%) and computerized group page (36.6%). Computerized group page (53.7%) and regular telephone (49.8%) were cited as the most advantageous devices; e-mail (52.3%) and dry erase whiteboard (52.1%) were selected as the least advantageous. Attending surgeons preferred less overhead paging and more cellular phone communication than did emergency medicine physicians and nurses. Cellular phones have become an important part of hospital–field communication. In high-volume trauma centers, there is a need for more accurate methods of communicating with field personnel and among hospital care providers.

In-vehicle workload assessment: Effects of traffic situations and cellular telephone use

Problem: Assessment of drivers' on-road workload is an important traffic safety consideration. This study was conducted to examine the effects of cellular phone communication on driving performance, with particular emphasis on variations in task demand in different traffic situations. Method: Twelve participants were asked to drive on urban roads and motorways with or without concomitant mathematical-addition tests relayed via cellular phone. Measurements included task and driving performance, physiological responses, and compensatory behavior. Results: Analysis of task performance revealed that mean response time was markedly increased (11.9%) for driving on urban roads compared to motorways. The mean driving speed only decreased 5.8% in the presence of phone tasks in comparison to normal driving without distractions. In addition, overall physiological workload increased through compensatory behavior in response to the phone tasks. Conclusions: Driving with phone use in different traffic environments induced measurable variations in driver workload. Impact on Industry: When faced with heavy traffic, a greater safety margin is typically adopted, with more lowered driving speed and restricted phone use, and it can be assumed that there is a general trade-off between tasks to preserve driving safety.

An HTS X-band DC SQUID based amplifier: Modeling and development concepts

We present an X-band amplifier concept based on a HTS grain boundary dc SQUID, which allow for extended dynamic range for use with SIS mixers, e.g., as a buffer amplifier in front of an RSFQ ADC, or possibly for satellite and cellular phone communications. The proposed RF design is based on a combination of single-layer slot and coplanar lines forming novel input and output circuits. The following parameters (per stage) are obtained via simulation for central frequency 11 GHz: bandwidth 0.5-1 GHz, power gain 11-12 dB, noise temperature 5-10 K. A saturation product as high as 500-1000 K/spl middot/GHz is estimated for a characteristic voltage of 1-2 mV. The realization of these parameters makes HTS SQA competitive with existing coolable HEMT-amplifiers for radio astronomy and satellite communication.

HTS dc SQUID based rf amplifier: development concept

We present a concept of a rf amplifier based on a directly coupled dc SQUID with bicrystal junctions, which have high saturation power and can be used with SIS mixers or possibly for satellite and cellular phone communications. A novel input resonant circuit is proposed using single layer of HTS. Estimated parameters are (per stage): central frequency≈11 GHz, bandwidth≈400 MHz, noise temperature≈10 K, gain≈10 dB and input saturation≈1000 K GHz.

Neoplastic transformation in C3H 10T(1/2) cells after exposure to 835.62 MHz FDMA and 847.74 MHz CDMA radiations.

The effect of radiofrequency (RF) radiation in the cellular phone communication range (835.62 MHz frequency division multiple access, FDMA; 847.74 MHz code division multiple access, CDMA) on neoplastic transformation frequency was measured using the in vitro C3H 10T(1/2) cell transformation assay system. To determine if 835.62 MHz FDMA or 847.74 MHz CDMA radiations have any genotoxic effects that induce neoplastic transformation, C3H 10T(1/2) cells were exposed at 37 degrees C to either of the above radiations [each at a specific absorption rate (SAR) of 0.6 W/kg] or sham-exposed at the same time for 7 days. After the culture medium was changed, the cultures were transferred to incubators and refed with fresh growth medium every 7 days. After 42 days, the cells were fixed and stained with Giemsa, and transformed foci were scored. To determine if exposure to 835.62 MHz FDMA or 847.74 MHz CDMA radiation has any epigenetic effects that can promote neoplastic transformation, cells were first exposed to 4.5 Gy of X rays to induce the transformation process and then exposed to the above radiations (SAR = 0.6 W/kg) in temperature-controlled irradiators with weekly refeeding for 42 days. After both the 7-day RF exposure and the 42-day RF exposure after X irradiation, no statistically significant differences in the transformation frequencies were observed between incubator controls, the sham-exposed (maintained in irradiators without power to the antenna), and the 835.62 MHz FDMA or 847.74 MHz CDMA-exposed groups.

A fast 3D modeling approach to electrical parameters extraction of bonding wires for RF circuits

Bonding wires are extensively used in integrated circuit (IC) packaging and circuit design in RF applications. An approach to fast three-dimensional (3D) modeling of the geometry for bonding wires in RF circuits and packages is demonstrated. The geometry can readily be used to extract electrical parameters such as inductance and capacitance. An equivalent circuit is presented to model the frequency response of bonding wires. To verify simulation accuracy, test structures have been made and measured. Excellent agreement between simulated and measured data is achieved for frequencies up to 10 GHz. The model is well suited for the design and analysis of circuits for cellular phone communication (i.e., order 2 GHz) and future wireless communication (i.e., order 5 GHz).

Proto-Oncogene mRNA Levels and Activities of Multiple Transcription Factors in C3H 10T 1/2 Murine Embryonic Fibroblasts Exposed to 835.62 and 847.74 MHz Cellular Phone Communication Frequency Radiation

This study was designed to determine whether two differently modulated radiofrequencies of the type generally used in cellular phone communications could elicit a general stress response in a biological system. The two modulations and frequencies studied were a frequency-modulated continuous wave (FMCW) with a carrier frequency of 835.62 MHz and a code division multiple-access (CDMA) modulation centered on 847.74 MHz. Changes in proto-oncogene expression, determined by measuring Fos, Jun, and Myc mRNA levels as well as by the DNA-binding activity of the AP1, AP2 and NF-kappaB transcription factors, were used as indicators of a general stress response. The effect of radiofrequency exposure on proto-oncogene expression was assessed (1) in exponentially growing C3H 10T 1/2 mouse embryo fibroblasts during their transition to plateau phase and (2) during transition of serum-deprived cells to the proliferation cycle after serum stimulation. Exposure of serum-deprived cells to 835.62 MHz FMCW or 847.74 MHz CDMA microwaves (at an average specific absorption rate, SAR, of 0.6 W/kg) did not significantly change the kinetics of proto-oncogene expression after serum stimulation. Similarly, these exposures did not affect either the Jun and Myc mRNA levels or the DNA-binding activity of AP1, AP2 and NF-kappaB in exponential cells during transit to plateau-phase growth. Therefore, these results suggest that the radiofrequency exposure is unlikely to elicit a general stress response in cells of this cell line under these conditions. However, statistically significant increases (approximately 2-fold, P = 0.001) in Fos mRNA levels were detected in exponential cells in transit to the plateau phase and in plateau-phase cells exposed to 835.62 MHz FMCW microwaves. For 847.74 MHz CDMA exposure, the increase was 1.4-fold (P = 0.04). This increase in Fos expression suggests that expression of specific genes could be affected by radiofrequency exposure.

Measurement of DNA Damage after Exposure to Electromagnetic Radiation in the Cellular Phone Communication Frequency Band (835.62 and 847.74 MHz)

Mouse C3H 10T1/2 fibroblasts and human glioblastoma U87MG cells were exposed to cellular phone communication frequency radiations to investigate whether such exposure produces DNA damage in in vitro cultures. Two types of frequency modulations were studied: frequency-modulated continuous-wave (FMCW), with a carrier frequency of 835.62 MHz, and code-division multiple-access (CDMA) centered on 847.74 MHz. Exponentially growing (U87MG and C3H 10T1/2 cells) and plateau-phase (C3H 10T1/2 cells) cultures were exposed to either FMCW or CDMA radiation for varying periods up to 24 h in specially designed radial transmission lines (RTLs) that provided relatively uniform exposure with a specific absorption rate (SAR) of 0.6 W/kg. Temperatures in the RTLs were monitored continuously and maintained at 37 +/- 0.3 degrees C. Sham exposure of cultures in an RTL (negative control) and 137Cs gamma-irradiated samples (positive control) were included with every experiment. The alkaline comet assay as described by Olive et al. (Exp. Cell Res. 198, 259-269, 1992) was used to measure DNA damage. No significant differences were observed between the test group exposed to FMCW or CDMA radiation and the sham-treated negative controls. Our results indicate that exposure of cultured mammalian cells to cellular phone communication frequencies under these conditions at an SAR of 0.6 W/kg does not cause DNA damage as measured by the alkaline comet assay.

A STATISTICAL ANALYSIS OF REAL TIME LONG RANGE GPS MEASUREMENTS VIA CELLULAR PHONE COMMUNICATION

A fully automated GPS base station was set up at the University of Otago, Dunedin, New Zealand in December 1995. The station provides real time differential corrections and carrier phase data to GPS users in the region, 24 hours a day. Tests are needed to look at the possibility of using these data for real time long range applications and to determine the achievable positional accuracy of the various long range positioning techniques. A test was initiated to study On The Fly fixed (OTF Fix), On The Fly float (OTF Float), and DGPS techniques using cellular phone communication in late December 1995. Further testing of cellular phone communication and OTF technique for rural cadastral surveying was conducted soon after. Evaluation of the positional accuracy of these techniques was based on the vector solution of precise relative static observations.Long range test results show that the horizontal accuracy of the OTF fix technique at a 95% confidence level is better than ten centimetres (10 cm) under thirty kilometres and twenty centimetres (20 cm) up to sixty kilometres. The OTF float technique is better than fifty centimetres (50 cm) up to 100 kilometres while DGPS is better than one and a half metres (l.5 m) up to 190 kilometres.Cadastral application test results show that the direct setup 95% probability error ellipse is six square centimetres. Indirect setup 95% probability error ellipse is ten square centimetres which is similar to the computed value using the principle of error propagation.

A STATISTICAL ANALYSIS OF REAL TIME LONG RANGE GPS MEASUREMENTS VIA CELLULAR PHONE COMMUNICATION

A fully automated GPS base station was set up at the University of Otago, Dunedin, New Zealand in December 1995. The station provides real time differential corrections and carrier phase data to GPS users in the region, 24 hours a day. Tests are needed to look at the possibility of using these data for real time long range applications and to determine the achievable positional accuracy of the various long range positioning techniques. A test was initiated to study On The Fly fixed (OTF Fix), On The Fly float (OTF Float), and DGPS techniques using cellular phone communication in late December 1995. Further testing of cellular phone communication and OTF technique for rural cadastral surveying was conducted soon after. Evaluation of the positional accuracy of these techniques was based on the vector solution of precise relative static observations.Long range test results show that the horizontal accuracy of the OTF fix technique at a 95% confidence level is better than ten centimetres (10 cm) under thirty kilometres and twenty centimetres (20 cm) up to sixty kilometres. The OTF float technique is better than fifty centimetres (50 cm) up to 100 kilometres while DGPS is better than one and a half metres (l.5 m) up to 190 kilometres.Cadastral application test results show that the direct setup 95% probability error ellipse is six square centimetres. Indirect setup 95% probability error ellipse is ten square centimetres which is similar to the computed value using the principle of error propagation.

Workload Assessment of IN-CAB Text Message System and Cellular Phone Use by Heavy Vehicle Drivers on the Road

This study assessed the driver workload imposed by a text messaging system and cellular phone on heavy vehicle drivers under various driving conditions. Sixteen (16) professional commercial vehicle operation (CVO) licensed drivers drove an instrumented heavy truck over a 4-hour period on public roads under various conditions of ambient lighting (day or night), traffic density (light or heavy), and road type (divided or undivided). Within driving condition combinations, various levels of text message reading, cellular phone dialing, radio tuning, and communications dialogue were completed by the driver. Continuous measures were taken of visual allocation, steering and accelerator activity, speed maintenance and lane-keeping performance. Results of in-vehicle device use are presented and provide insights into useful workload measures and methods, as well as a contribution to the literature on cellular phone and in-vehicle text messaging system ergonomics.