Minimum payment collaborative sensing network using mobile phones

Mobile phones with embedded sensors have been applied in various collaborative sensing applications. To encourage mobile phone users to perform collaborative sensing, the data demanders usually pay mobile phone users for required data. In this paper, we study the Minimum Payment of Attaining the Required Data with mobile phones (MPARD) problem in collaborative sensing network: given sensing regions \(R = \{R_1, R_2, \ldots , R_m\}\) , the set of requisite data \(D_i\) for each sensing region \(R_i\) and a set of mobile phones \(M\) , the \(MPARD\) problem studies how to select mobile phones to obtain all the required data such that the data demanders’ total payment to mobile phone users is minimized. In reality, some systems need the fresh sensing data from mobile phones at each pre-determined time slot, and others don’t require the real-time data and the sensing data from previous time slots is also deemed useful. Based on the above two different requirements of data timeliness, we first define two subproblems derived from \(MPARD\) problem: \(MPARD_t\) and \(MPARD_p\) . After that, for each subproblem, we propose an approximation algorithm for the situation where the trajectories of mobile phones are determinate and a heuristic for the situation where trajectories are unknown. Simulation results demonstrate that our algorithms are efficient.     

Compressed sensing method for human activity recognition using tri-axis accelerometer on mobile phone

The diversity in the phone placements of different mobile users' dailylife increases the difficulty of recognizing human activities by using mobile phone accelerometer data. To solve this problem, a compressed sensing method to recognize human activities that is based on compressed sensing theory and utilizes both raw mobile phone accelerometer data and phone placement information is proposed. First, an over-complete dictionary matrix is constructed using sufficient raw tri-axis acceleration data labeled with phone placement information. Then, the sparse coefficient is evaluated for the samples that need to be tested by resolving L1 minimization. Finally, residual values are calculated and the minimum value is selected as the indicator to obtain the recognition results. Experimental results show that this method can achieve a recognition accuracy reaching 89.86%, which is higher than that of a recognition method that does not adopt the phone placement information for the recognition process. The recognition accuracy of the proposed method is effective and satisfactory.     

移动电话组件技术

由于半导体技术的大幅提高,现在移动电话的功能远远超越10年前的机型,而且体积与价格也大幅降低。现代手机中的硬件电路仍包含射频(RF)、基带以及功率管理等组件,新旧手机之间的差异体现在集成度和额外组件上,例如多媒体应用处理、相机、MMS、彩屏、FM收音机、MP3、游戏、GPS全球定位系统以及各种连网技术。随着移动电话     

行业安全手机探索研究

党政军、学校、企业等特殊行业主要移动互联网安全问题是接入设备安全、移动应用安全、用户接入认证安全等.本文将从操作系统安全、应用程序安全、设备管理安全、网络传输安全4个方面进行讨论,实行对手机的全面安全防护,为行业安全提供成套解决方案.     

Nanostructures for chemical recognition using ISFET sensors

The application of Langmuir-Blodgett (LB)-fabricated nanostructures on Ion selective Field Effect Transistors (ISFET) is of great interest since it permits the combination of a micro-scale device with a nanoscale material. In this article, the optimization of a LB-monolayer for calcium and sodium detection is carried out by characterization with XPS and AFM techniques, followed by electrochemical characterisation onto ISFET sensors. Physico-chemical modifications of the surface and good cation complexation of the ionophores fixed in the monolayers were observed with XPS studies. AFM images showed the presence of a unhomogeneous layer all over the ISFET surface. The electrochemical response of those monolayers onto ISFETs demonstrated the feasibility of this technology for sensor membrane fabrication and it opens further studies for other kind of devices such as optochemical sensors.     

手机TV技术闪亮登场

随着通信技术的不断发展，手机的功能越来越多。当前在手机市场已经出现了具有超高像素的拍照手机、整合MP3功能的音乐手机、集多种功能于一身的高级智能手机、可以随时随地收看电视节目的视频手机等。特别是电视视频手机(本文以下称“手机TV”）．将会把终端市场打造得更为精彩，给消费者带来更加丰富的信息内容，颇受业界青睐。     

Big push is on [mobile phones]

Nokia's announcement that all its new handsets will include 'push to talk' (PTT) as a standard feature means that 2004 could be the year when text messaging is finally eclipsed as the dominant mobile technology. Already established for business use in the US, PTT is predicted to create a new telecoms market worth more than $50bn within five years. The technology is usually likened to giving handsets walkie talkie functionality, allowing groups of up to 10 users to communicate without dialling a number or waiting for anyone to pick up. Benefits for business users-like security patrols or maintenance staff who operate over a wide area but need to keep in touch are obvious and outweigh the fact that only one person can speak at a time.     

Multiband internal antenna for mobile phones

A new internal antenna for multiband cellphones comprises a U-shaped elongated flat conductor featuring a closed meandered slot, a ground and a feed leg. A benchmark on a Motorola T192 handset is conducted to illustrate the operation of this structure - called a folded inverted conformal antenna showing significantly more radiating bandwidth than a conventional dual-band PIFA.     

Nine-band antenna system for mobile phones

A physically and electrically small system of antennas, installed at the top of a 'monoblock' or 'bar' phone, is presented. The antennas cover nine bands - five cellular bands, the GPS and Bluetooth/WiFi bands and two future mobile TV bands.     

All-digital PLL and transmitter for mobile phones

We present the first all-digital PLL and polar transmitter for mobile phones. They are part of a single-chip GSM/EDGE transceiver SoC fabricated in a 90 nm digital CMOS process. The circuits are architectured from the ground up to be compatible with digital deep-submicron CMOS processes and be readily integrateable with a digital baseband and application processor. To achieve this, we exploit the new paradigm of a deep-submicron CMOS process environment by leveraging on the fast switching times of MOS transistors, the fine lithography and the precise device matching, while avoiding problems related to the limited voltage headroom. The transmitter architecture is fully digital and utilizes the wideband direct frequency modulation capability of the all-digital PLL. The amplitude modulation is realized digitally by regulating the number of active NMOS transistor switches in accordance with the instantaneous amplitude. The conventional RF frequency synthesizer architecture, based on a voltage-controlled oscillator and phase/frequency detector and charge-pump combination, has been replaced with a digitally controlled oscillator and a time-to-digital converter. The transmitter performs GMSK modulation with less than 0.5/spl deg/ rms phase error, -165 dBc/Hz phase noise at 20 MHz offset, and 10 /spl mu/s settling time. The 8-PSK EDGE spectral mask is met with 1.2% EVM. The transmitter occupies 1.5 mm/sup 2/ and consumes 42 mA at 1.2 V supply while producing 6 dBm RF output power.     

Investigating text input methods for mobile phones

Human Computer Interaction is a primary factor in the success or failure of any device but if an objective view is taken of the current mobile phone market you would be forgiven for thinking usability was secondary to aesthetics. Many phone manufacturers modify the design of phones to be different than the competition and to target fashion trends, usually at the expense of usability and performance. There is a lack of awareness among many buyers of the usability of the device they are purchasing and the disposability of modern technology is an effect rather than a cause of this. Designing new text entry methods for mobile devices can be expensive and labour-intensive. The assessment and comparison of a new text entry method with current methods is a necessary part of the design process. The best way to do this is through an empirical evaluation. The aim of the paper is to establish which mobile phone text input method best suits the requirements of a select group of target users. This study used a diverse range of users to compare devices that are in everyday use by most of the adult population. The proliferation of the devices is as yet unmatched by the study of their application and the consideration of their user friendliness.     

An information-theoretic framework for field monitoring using autonomously mobile sensors

We consider a mobile sensor network monitoring a spatio-temporal field. Given limited caches at the sensor nodes, the goal is to develop a distributed cache management algorithm to efficiently answer queries with a known probability distribution over the spatial dimension. First, we propose a novel distributed information theoretic approach assuming knowledge of the distribution of the monitored phenomenon. Under this scheme, nodes minimize an entropic utility function that captures the average amount of uncertainty in queries given the probability distribution of query locations. Second, we propose a correlation-based technique, which only requires knowledge of the second-order statistics, relaxing the stringent constraint of a priori knowledge of the query distribution, while significantly reducing the computational overhead. We show that the proposed approaches considerably improve the average field estimation error. Further, we show that the correlation-based technique is robust to model mismatch in case of imperfect knowledge of the underlying generative correlation structure.     

Digital tracking array using off-the-shelf hardware

The design, development, and testing of a digital tracking array is described. The array operates at 2.4 GHz for tracking video and data from UAVs and other mobile transmitters. A monopulse tracking technique is used to keep the beam scanned to the direction of the incoming signal. The array is built entirely of commercial off-the-shelf (COTS) components. Calibration, measurement of patterns, and verification of the tracking function are also discussed.     

Trajectory identification based on spatio-temporal proximity patterns between mobile phones

Growing popularity of location-dependent mobile applications is continuously stimulating a demand for localization technology. However, in spite of significant research effort in the past decade, precise positioning in indoor environments is still an open problem. In this paper, we propose a novel type of indoor localization system that provides mobile phone users in a pedestrian crowd with their own position information of sub-meter accuracy by effectively utilizing a powerful pedestrian tracking capability of laser range scanners (i.e., laser-based distance measurement sensors). Although the laser-based tracking system can precisely detect presence of pedestrians at each location in its sensing region, the location information is not associated with any mobile phone users and thus it basically cannot provide the users’ own locations. To remove this limitation, we focus on spatio-temporal proximity patterns between mobile phones, which can be detected by peer-to-peer short-range wireless communication (e.g., Bluetooth). By examining consistency between the communication logs and proximity between anonymous trajectories detected by laser-based tracking, our system identifies a trajectory that corresponds to each mobile phone user to offer their own position information. Through extensive simulations and field experiments, we show that our system can achieve trajectory identification accuracy of up to 91 %.     

The distributional effects of leapfrogging in mobile phones

This paper uses theory and empirical evidence to analyze the distributional effects of leapfrogging in mobile phones. The theory draws on earlier work on leapfrogging and Sen’s model of functionings and capabilities. The evidence draws partly on simple regression analysis. A key role is assigned to fixed-line telephony in reaching the conclusion that leapfrogging in mobile phones tends overall to be egalitarian in its impact on different developing countries. Mobiles however constitute very much the exception when it comes to technological relationships between rich and poor countries.     

Statistics of measured body loss for mobile phones

The variation in body loss for different users of a cellular handset is investigated. Measurements involving 200 test users of mobile communications (GSM) handsets have been performed and statistics are presented for a handset with three types of antennas. Differences in the body loss of up to 10 dB have been observed between users, thus indicating that body loss measurements for handsets should include several test persons. Depending on the antenna type, 8-13 test persons are required to obtain an estimate of the mean body loss with a ±1 dB confidence interval at a 90% level     

基于光栅的手机多视点立体显示技术研究

研究了基于多视点立体视频处理系统的手机客户终端显示技术。针对现有的8视点光栅立体手机显示技术的缺陷,在原有8视点立体图像合成算法的基础上,研究视差原理及校正方法和视点配对原理,采用调整视点间视差和减少视点数两种解决方案,并提出将两种方案进行结合的方法。经实验验证,本文提出的两种方法在保证原有立体显示效果的基础上,大幅度提高了立体显示的舒适度。     

Evaluation of radiation exposure by UMTS mobile phones

An overview of the radiated power by a UMTS mobile phone in everyday usage is given. Compared to GSM, the exposure is presently about a thousandfold lower in comparable situations. Both location and time dependence as well as the control of the output power have been investigated using operating networks in Germany.     

The Queen of SIMs [mobile phones]

The SIM (Subscriber Identity Module) transformed the smartcard business as mobile phones started to flourish and each had to carry one. But, as the networks become increasingly complex, offering a multiplicity of capabilities to the users-multimedia applications, high-performance processing, large storage and commerce-the complexity of the SIM grows, too. The USIM (Universal Subscriber Identity Module) will improve the relationship with the users and it's a good candidate to enable content delivery. The USIM is expected to offer higher capacities, going into the megabyte domain, to be able to store even more data to meet the growing number of applications in its pitch to be 'all things to all people'.