Terminal Users Research Articles

Research and design of multimode GNSS antenna technology

With the merits of wide coverage, huge capacity of communications, good transmission quality, etc., Global Satellite Navigation System (GNSS) plays a vital role in the fields, such as the aviation, marine, mapping, timing and information services. As the essential part of satellite navigation system, Antenna’s overall performance is good or bad which have a significant impact on Navigation and Positioning System. In this paper, a multi-mode circular polarization GNSS antenna with single-feed stacked patch combined stub technology is presented. By inserting different cross shape stubs, the top square patch performs GNSS high frequency multi-band circular polarization, and the right-hand circular polarization mode in the GNSS low frequency is achieved through inserting different cross shape stubs in the center of the lower square patch. Theoretical analysis and simulation results show that the proposed multi-mode circular polarization antenna can meet multi-system positioning needs of the terminal users of satellite navigation.

Study on Specialized Emergency Navigation Terminal for Disaster Relief

Aimed at the great demand dealing with our natural disaster, it is important to carry on integrated technologies like satellite navigation and positioning monitoring, embedded geographic information system and sensing technology etc. Also, to accomplish the seamless connection with nation’s disaster assessment system in various environments when the communication links are clear and accurate, to realize the disaster information obtained quickly and shared rapidly together with the reliable orientation navigation provided by the disaster terminal users and quick inquiry and effective adjustments for relief workers or relief supplies. Above integrated technologies have set a technological foundation for national disaster relief command system, which is of great importance when considering enhancing the ability for national emergency relief.

Blink Rate, Blink Amplitude, and Tear Film Integrity during Dynamic Visual Display Terminal Tasks

Purpose: The present study aimed at investigating the influence of the level of dynamism of two different visual display terminal tasks on spontaneous eyeblink rate, blink amplitude, and tear film integrity.Material and Methods: A total of 25 healthy, young volunteers participated in the study. Blink rate and blink amplitude were recorded in silent primary gaze conditions and while subjects were playing two computer games of similar cognitive demands but different rate of visual information presentation. For each experimental condition, tear volume was evaluated by measuring meniscus height and with the red phenol thread test. Fluorescein and non-invasive break-up time tests, as well as the observation of interference patterns and the estimation of the dry area extension, were employed to assess tear stability.Results: Statistically significant differences were revealed in blink rate (F = 595.85, p < 0.001) and blink amplitude (χ2 = 34.00, p < 0.001), with blink rate during fast- and slow-paced game play decreasing to almost 1/3 and 1/2 of baseline levels, respectively, and with a larger percentage of incomplete blinks during dynamic tasks. Fluorescein and non-invasive break-up time tests and dry area extension were able to differentiate between experimental conditions in general (F = 408.42, p < 0.001; F = 163.49, p < 0.001; χ2 = 20.74, p < 0.001), as well as between fast- and slow-paced games, thus suggesting that tear quality was more affected than tear volume.Conclusions: Blink rate, blink amplitude, and tear film stability were compromised during the most dynamic visual display terminal task, suggesting a negative influence of not only the cognitive aspects of the task, but also of the rate at which new visual information is presented. Frequent breaks and blinking awareness training are recommended for visual display terminal users requiring prolonged periods of visually demanding dynamic computer play or work.

CAD Graphic Preview and Interaction of the Mould Collaborative Design

CAD graphic preview and interaction is a key problem in the mould collaborative design syetem. It can realize with Java Applet program, but it is necessary to development Java Applet program,that will restrict many terminal users of the mould collaborative design syetem. In order to realize the problem that terminal users can preview CAD graphic, correct and transfer the CAD graphic to other terminal users easily and quickly, this paper put forward a way that terminal users can use previewing the original data file of AutoCAD graphic, correcting and transfering the CAD graphic to other terminal users,the way is using the Voloview control program which developed by Autodesk company, and put forward the concrete methods and steps to achieve. Test shows that, the way can meet the terminal users requirements and implementation in mold collaborative design syetem.

Building a Cloud Storage Service System

Abstract Cloud Storage services are increasingly noticed as they promise elastic capability and high reliability at low cost. In such services, you can store most of your files to authenticated Cloud Storage Service center, and you do not worry about your space being inadequate or wasted because the storage being able to be adjusted dynamically is the most important feature of the Cloud Storage. In this paper, we present a solution about how to build a Cloud Storage Service System based on the open-source distributed database, it follows a stratum design that includes Web service front-end, transformation processing layer and data storing layer. Terminal users can access their own data in this system through three Web service interfaces. More over, a complete prototype system based on this architecture is demonstrated.

Neck–Upper Extremity Musculoskeletal Disorders Among Workers in the Telecommunications Company at Mansoura City

Objectives. This study was to determine the prevalence and work-related risk factors of neck-upper extremity musculoskeletal disorders (MSDs) among video display terminal (VDT) users. Methods. A comparative cross-sectional study was conducted; there were 60 VDT users and 35 controls. The participants filled in a structured questionnaire, had electrophysiological tests and an X-ray of the neck. Results. The prevalence of MSDs was higher (28.3%) among VDTs users compared to controls (14.3%) with no statistically significant difference. The prevalence of cervical disorders with or without radiculopathy ( 18.3%) was the most common disorder followed by carpal tunnel syndrome (6.6%). The mean (SD) age of MSD cases (51 ± 7.2 years) was statistically significantly higher than of the controls (42.8 ± 9). Physical exposure to prolonged static posture (OR: 6.9; 95% CI: 0.83–57.9), awkward posture (OR: 5.5; 95% CI: 0.6–46.4) and repetitive movements (OR: 5.5; 95% CI: 0.65–46.4) increased risk of MSDs with a statistically significant difference for static posture only (p < .05). VDT users experienced more job dissatisfaction, work-overload and limited social support from supervisors and colleagues. Conclusion. VDT use did not increase the risk of neck–upper extremity MSDs. The risk increased with older age and static posture.

Operational Performance Evaluation of Korean Major Container Terminals

As the competition among the container terminals in Korea has become increasingly fierce, every terminal is striving to increase its investments constantly and lower its operational costs in order to maintain the competitive edge and provide satisfactory services to terminal users. The unreasoning behavior, however, has induced that substantial waste and inefficiency exists in container terminal production. Therefore, it is of great importance for the terminal to know whether it has fully used its existing infrastructures and that output has been maximized given the input. From this perspective, data envelopment analysis (DEA) provides a more appropriate benchmark. This study applies three models of DEA to acquire a variety of analytical results about the operational efficiency to the Korean container terminals. According to efficiency value analysis, this study first finds the reason of inefficiency. It is followed by identification of the potential areas of improvement for inefficient terminals by applying slack variable method and giving the projection results. Finally, return to scale approach is used to assess whether each terminal is in a state of increasing, decreasing, or constant return to scale. The results of this study can provide terminal managers with insight into resource allocation and optimization of the operating performance.

Carrier ethernet for mobile backhaul

The wide adoption of mobile broadband services by users of smartphones and other mobile terminals is being enabled by radio access technologies with better performance than many fixed residential broadband lines. Mobile network operators are upgrading their networks to deliver growing packet traffic cost effectively, while maintaining critical operational functions such as base station synchronization and resilience to faults. Carrier Ethernet technology is figuring strongly in the upgrade from the existing TDM mobile backhaul between radio base stations and mobile core networks.

An online tool to identify white-collar worker profiles in relation to their ICT skills and mental strain

The introduction of Internet and Information and communication Technologies (ICT) in offices is a global phenomenon that transformed white-collar worker job demands. Although there are several studies of e-skills and mental workload for central countries, there is a lack of similar studies for the Latin American context. An online snowball sampled (n = 352) survey was developed and validated by the authors (internal consistency = 0.7). We characterized ICT worker profiles from e-skills and these dimensions: attitudes toward, resources usage and technology dependency. Mental Strain was assessed with raw task load index (RTLX) and correlated with the proposed profiles by means of paired T-tests and Mann–Whitney Tests. The sample was characterized by 7.2% of non visual display terminal users and 92.8% of visual display terminal, ICT skilled users. Of the latter, 30.7% were ICT practitioners, 30.4% were ICT Users and 27.2% were E-Business Users. Non VDT users’ mental strain was statistically meaningful smaller than VDT–ICT skilled users’ mental workload. No statistical differences were found in RTLX results when comparing ICT skilled user profiles. Non VDT users can be identified from ICT skilled Users by their lower ITC Dependency and minor use of ICT resources. There were no differences in those dimensions among ICT skilled Profiles. Attitude toward these technologies was a distinct factor for ICT Users in relation to ICT Practitioners and ITC Business Users. The application of this tool in peripheral and central countries would allow a complete ergonomical characterization of white-collar workers within the Information Society.

Lacrimal Hypofunction as a New Mechanism of Dry Eye in Visual Display Terminal Users

BackgroundDry eye has shown a marked increase due to visual display terminal (VDT) use. It remains unclear whether reduced blinking while focusing can have a direct deleterious impact on the lacrimal gland function. To address this issue that potentially affects the life quality, we conducted a large-scale epidemiological study of VDT users and an animal study.Methodology/Principal FindingsCross sectional survey carried out in Japan. A total of 1025 office workers who use VDT were enrolled. The association between VDT work duration and changes in tear film status, precorneal tear stability, lipid layer status and tear secretion were analyzed. For the animal model study, the rat VDT user model, placing rats onto a balance swing in combination with exposure to an evaporative environment was used to analyze lacrimal gland function. There was no positive relationship between VDT working duration and change in tear film stability and lipid layer status. The odds ratio for decrease in Schirmer score, index of tear secretion, were significantly increased with VDT working year (P = 0.012) and time (P = 0.005). The rat VDT user model, showed chronic reduction of tear secretion and was accompanied by an impairment of the lacrimal gland function and morphology. This dysfunction was recovered when rats were moved to resting conditions without the swing.Conclusions/SignificanceThese data suggest that lacrimal gland hypofunction is associated with VDT use and may be a critical mechanism for VDT-associated dry eye. We believe this to be the first mechanistic link to the pathogenesis of dry eye in office workers.

Visual Symptoms Among Non-presbyopic Video Display Tterminal (VDT) Operators In Owerri, Nigeria

Visual symptoms appear to be themost frequent and most disturbing of computer associated health problems. This study was aimed at investigating the most prevalent visual symptoms encountered among Video Display Terminal (VDT) users in Owerri municipality prior to presbyopic onset. A total of one hundred and eighty-six (186) respondents, comprising 57 males and 129 females in the age bracket of 17-34years (mean age: 25.83±4.90years) were divided into two (2) groups: groupAcomprises of forty (40) non-VDT users and, group B comprises of one hundred and forty-six(146) VDT users. Each group was investigated, using pre-sampling criteria of visual acuity screening and ocular health assessment, before being handed a well-structured questionnaire, to be filled individually. Data consequently obtained revealed that headache (41.78%); eyestrain (26.72%), pain (31.51%) and lacrimation (19.86%) were the most prevalent visual symptoms among non-presbyopic, Owerri-based. VDT users.Acomparative one-tailed statistical analysis using the Z-test (0.05) revealed that VDT usage increases the prevalence of visual symptoms among users (P> 0.05). It was also revealed that Owerribased, non-presbyopic VDToperators are exposed to environmental risk factors hazardous to them while working. Consequently, this study suggests that intervention programs aimed at ameliorating these problems and the predisposing factors be introduced and sustained, to forestall the outbreak of a dangerous health problem due to VDT usage.

A Comparison of Scheduling Strategies for MIMO Broadcast Channel with Limited Feedback on OFDM Systems

We consider a multiuser downlink transmission from a base station with multiple antennas (MIMO) to mobile terminals (users) with a single antenna, using orthogonal frequency division multiplexing (OFDM). Channel conditions are reported by a feedback from users with limited rate, and the base station schedules transmissions and beamforms signals to users. We show that an important set of schedulers using a general utility function can be reduced to a scheduler maximizing the weighted sum rate of the system. For this case we then focus on scheduling methods with many users and OFDM subcarriers. Various scheduling strategies are compared in terms of achieved throughput and computational complexity and a good tradeoff is identified in greedy and semiorthogonal user selection algorithms. In the greedy selection algorithm, users are selected one by one as long as the throughput increases, while in the semiorthogonal approach users are selected based on the channel correlation. An extension of these approaches from a flat-fading channel to OFDM is considered and simplifications that may be useful for a large number of subcarriers are presented. Results are reported for a typical cellular transmission of the long-term evolution (LTE) of 3GPP.

Asthenopia and Use of Glasses among Visual Display Terminal (VDT) Users

Asthenopia and Use of Glasses among Visual Display Terminal (VDT) Users

USING Hybrid Adaptive Techniques to Reduce Multipath Effects in S-PCN Mobile Terminals

Multipath signal processing is a promising technique for increasing the capacity of downlink frequency of satellite communication networks (S-PCN). The paper presents an approach to processing and reducing multipath signals received from S-PCN typified of mobile terminal users in clustered or mountainous environment. Use of hybrid linear adaptive antenna array technique and adaptive filtering technique provides improved performance by eliminating uncorrelated signal residing in antenna sidelobes.

Computer Vision Syndrome (CVS): Recognition and Control in Software Professionals

Musculoskeletal Disorders among video display terminal (VDT) users have become a worldwide problem. Computer Vision Syndrome holds the distinction of being called the number one occupational hazard of the 21st century. Prevention of injury and illness is, obviously, the best approach, but comprehensive health care and safety programs can help to reduce corporate sector's workplace injuries, absenteeism or presenteeism and related expenses. A fitness program was designed to reduce the symptoms of CVS in software professionals. A pre and post-test study was conducted to evaluate the effect of the fitness program. The study revealed that the fitness program helped to reduce the symptoms of CVS in software professionals.

Comparative study of the blinking time between young adult and adult video display terminal users in indoor environment

Investigate the average blinking time in conversation and in Video Display Terminal use of young adults and adults in the presbyopic age group. A transversal analytical study in a readily accessible sample consisting of Volkswagen do Brasil - Curitiba, Paraná employees was performed. The cohort group consisted of 108 subjects divided into two age groups: Group 1, the young adult group (age range 20-39): 77 employees, mean age of 30.09 +/- 5.09; Group 2, the presbyopic adult group, (age range 40-53): 31 employees, mean age of 44.17 +/- 3. Subjects under 18 years of age, with a history of ocular disorders, contact lens wearers and computer non-users were excluded. The subjects had their faces filmed for 10 minutes in conversation and VDT reading. Student's t-test was used and the statistical significance level was 95%. The average time between blinks in Group 1 for conversation and VDT reading was 5.16 +/- 1.83 and 10.42 +/- 7.78 seconds, respectively; in Group 2. 4,9 +/- 1.49 and 10.46 +/- 5.54 seconds. In both age groups, the time between blinks in VDT reading situations was higher (p<0.0001). There was no statistically meaningful difference for conversation and VDT reading situations when the two studied age groups were compared (p>0.05). There was an increase in the blinking time between young adults and the presbyopic group in VDT use situations when compared with reading situations. The difference in the blinking frequency between young adults and the presbyopic group in VDT use and reading situations was not statistically significant.

Smart Front-End Signal Processing for Advanced Wireless Receivers

One of the key trends in the design of radio receivers and other wireless devices is to shift more and more of the transceiver functionalities to digital signal processing (DSP). At the same time, the demands on the remaining analog circuits are greatly increased, especially with lower power supplies and nanoscale technology effects such as variability. With the terminal users requesting high radio performance and data rates, and low power consumption on one hand, and terminal flexibility and reduced implementation costs on the other hand, the requirements for these remaining analog front-end stages become extremely challenging to meet. As a result, one interesting idea is to complement analog radio-frequency (RF) circuits with smart signal-processing algorithms to digitally enhanced RF circuits. In this paper, we focus on developing and demonstrating novel signal-processing techniques intended for the analog and digital front-ends of future low-power, flexible radios. One key aspect in the work is power-efficient digital front-end design with great flexibility for digital selectivity filtering and sample rate alteration. Another key ingredient is the analysis and mitigation of different analog RF impairments, with special emphasis on I/Q imbalance effects and second-order intermodulation (IM2) distortion in wideband multicarrier or multichannel radio receivers. The approach used in this work generally draws from the practical system performance specifications. Overall, our results clearly indicate that the proposed compensation techniques can be used to suppress I/Q imbalance and IM2 distortion effects in receiver front-end sections under realistic signaling assumptions. The adaptivity and flexibility offered by the overall digital front-end design greatly reduces the power consumption of the radio.

Modeling the Ambient Intelligence Application System: Concept, Software, Data, and Network

General reference models are essential for the ambient intelligence (AmI) system design, and they should be clear and simple both in terms of physical structure and software architecture. In this paper, we introduce a conceptual system model. According to this model, we present a physical structure model and a multiagent system based software architecture in the following step. We also give a data management mechanism model for the AmI environment. To evaluate our models, we implement them in a prototype ldquoSmart-Ovenrdquo system. Our models are suitable for rapid system modeling and development; they can help the designers and the programmers develop new AmI applications more rapidly and conveniently. Using the simplified AmI physical structure model, the physical AmI supporting environment can be established easily and rapidly. Via the software architecture and data management model, AmI application systems achieve flexibility, service discovery, and interoperability, which are the most common technical limitations in other related systems. Furthermore, our models can also help the terminal users configure their own AmI system by themselves. As a result of the works carried out in this paper, one can simplify the procedures and enhance the efficiency of AmI applications system design and development.

The Utilization of Push Mail in China

Push mail is popular to business users in the world. It has been two years since push mail was introduced into China. In order to find out the status of its development and utilization, investigation to push mail users is made. The results indicate that the existing subscribers are mostly managers of service enterprises in large and middle-size, such as manu-facturing, trade, IT and so on. In addition, those subscribers are satisfied with push mail, and would like to continue to use it in the following years. On the other hand, as it is still very small on the population to both terminal users and enterprise subscribers, some suggestions are made to induce push mail’s development.

NECK – UPPER EXTREMITY MUSCULOSKELETAL DISORDERS AMONG WORKERS IN EGYPTIAN TELECOMMUNICATIONS COMPANY AT MANSOURA CITY

The aim of this work was to study the prevalence of neck- upper extremity musculoskeletal disorders (MSD), mainly carpal tunnel syndrome (CTS), among video display terminal(VDT) users and to determine the association between CTS and occupational physical and psychosocial risk factors. A comparative cross- sectional study was conductedupon (60) VDT users (at risk group) and a matched control group composed of (35) non-VDT users. The population studied was subjected to a structured questionnaire, clinical examination, and investigation in the form of electrophysiological studies and of neck X- ray. There was no statistically significant difference in the prevalenceof neck -upper extremity MSD during the past year between the two groups. The prevalence of CTS among the VDT users was 3.3% which was similar to that found in other studies. The mean age of CTS cases (58±1.4years) was statistically significantly higher than the symptom- free VDT users (45.8±4.6years). The physical work stressorsand psychosocial factors were more common among CTS cases compared to non-cases, however, the difference was not statistically significant.