Capturing consumers’ experiences of unsolicited mobile advertising

The increasing numbers of telecoms subscribers in Nigeria and the concomitant spate of mobile advertising suggest that the time is ripe to begin to pay research attention to this area. Newspaper and anecdotal evidence in Nigeria suggest that consumers view such advertisements pejoratively since they are usually unsolicited. Therefore, the purpose of the present study was to use phenomenological design and semi-structured interviews to empirically examine consumers’ experiences as recipients of unsolicited phone call-based mobile advertising and efforts they have made thus far in addressing the issue. Twelve mobile subscribers (six males and six females) within the ages of 25 and 49 years participated in the study. Thematic analysis of the interviews revealed that consumers are generally resentful about unsolicited phone call-based mobile advertising. They may, however, be receptive to such advertising depending on whether they are informative and entertaining, permitted, and personalised to suit their mood, time, and context. Also, some consumers have not attempted to address the issue of unsolicited phone call-based mobile advertising whereas those that have tried before are reluctant in doing so again since previous attempts were unsuccessful. The implications of these findings to consumer satisfaction in telecoms sector in Nigeria were discussed. It was recommended that telecoms network operators in Nigeria should allow consumers to make their own choice and also consider consumers’ personal interests and preferences when designing mobile advertisements.     

Wide Dynamic Range in Tunable Electrochromic Bragg Stacks from Doped Semiconductor Nanocrystals

Electrochromic properties can be enhanced by constructing photonic architectures, in which the reflectance contributes to optical modulation along with the intrinsic dynamic absorptivity of the material. However, optimization of reflectance is challenging without a rational design approach. Here, electrochemically tunable Bragg reflectors are demonstrated that are tuned to be highly transparent in the “off” state, achieving synergistic dynamic optical modulation of absorption and reflection in the visible and near‐infrared range. These Bragg stacks are composed of alternating doped semiconductor nanocrystal (NC) layers of 5 nm sized oxygen vacancy‐doped WO_3?x and 15 nm sized 0.4 at% Sn:In₂O₃ NCs. Combining judicious NC selection and processing optimization with guidance from optical simulations, optimized Bragg stacks are implemented for electrochromic window applications. NCs with high absorption coefficients are essential for strong transmission modulation, though this characteristic limits the dynamic range of the Bragg reflectance. Optimal reflectance modulation including a highly transparent “off” state is confirmed with in situ reflectance and transmittance measurement. More broadly, ligand‐stripped NCs can enable fabrication of complex device architectures on low‐cost flexible substrates. These results guide the design rules for accessing different types of doped semiconductor NC‐based tunable Bragg stacks, an exemplary photonic structure, over a broad wavelength range.     

Organic Hybrid Perovskite (MAPbI3−xClx) for Thermochromic Smart Window with Strong Optical Regulation Ability,Low Transition Temperature,and Narrow Hysteresis Width

Recently, organic hybrid halide perovskites have been found to show thermochromism with good optical performance, which can be applied in smart windows to reduce building energy consumption. However, these perovskites have shortcomings regarding their thermochromic performance, namely long transition time, high transition temperature, and large transition hysteresis width. In this study, a hydrated MAPbI_3−xCl_x thermochromic perovskite smart window (H-MAPbI_3−xCl_x TPSW) is proposed, which undergoes a reversible transition between a transparent state and a dark reddish-brown tinted state with a high solar modulation ability of 23.7%. Most importantly, the H-MAPbI_3−xCl_x TPSW possesses a tunable low transition temperature of 29.4 to 51.4 °C, a controllable and narrow transition hysteresis width (7.7–13.2 °C) and a short transition time (1–4 min). Additionally, a mathematical model is developed to predict the transition temperature of the H-MAPbI_3−xCl_x TPSW. A field test is also conducted, demonstrating that the H-MAPbI_3−xCl_x TPSW fitted to a model house can reduce the indoor air temperature by 3.5 °C compared to using a quartz glass window. Overall, the H-MAPbI_3−xCl_x TPSW can yield excellent optical properties, while simultaneously providing remarkable transition properties, making it potentially useful for a wide range of applications in energy-efficient buildings.     

Digital background calibration of pipeline ADC based on correlation

Two novel calibration techniques based on dither injection and correlation are proposed. The first calibration algorithm utilises digital windows around the residue folding points by adding more comparators. Then all the capacitor mismatches and the linear gain error of the residue amplifier (RA) are calibrated by injecting dither signal in the windows. This new scheme would not change the key analogue signal path and thus brings no dither leakage in the digital domain. The other calibration algorithm injects dither signal into the split sampling capacitors to estimate the nonlinear kick-back error, which always exists in sample-hold amplifier less (SHA-less) structure. In addition, three other dither signals are injected into the added capacitors to calibrate the linear and nonlinear errors of the RA, which relaxes gain requirement in multiplying digtital-analogue-converter . Both the algorithms and the corresponding analogue-digital-converters (ADCs) are constructed and simulated in MATLAB. According to the simulation results, the first calibration technique increases signal-noise-distortion-ratio (SNDR) and spurious-free-dynamic-range (SFDR) by 40 and 42 dB, respectively. The second calibration scheme improves SNDR and SFDR by 19 and 34 dB in a SHA-less ADC.     

Humidity dependence of the atmospheric absorption coefficient in the transparency windows centered at 0.88 and 0.73 MM

A dependence is investigated of the absorption coefficient of atmospheric water vapor on absolute air humidity in the spectral intervals =11.1+12.0 and 13.2+14.3 cm^–1 by a radiospectrometer with a multipass vacuum cell. Measurements are carried out in the humidity range 3+23 g/m³ at 140 m length of the optical path.Parts of the absorption coefficient linearly and quadratically depending on have been separately defined from the experimental data. In particular, it has been obtained for the centers of transparency windows: (=0.73mm) [dB/km]=1.68 (±0.08) +0.019 (±0.004) ², (=0.88 mm) [dB/km]=0.83 (±0.06) +0.013 (±0.002) ². The given values correspond to the temperature of 306 K and the pressure of dry air of 735 Torr.A comparison is made between our results and theoretical calculations and data of other measurements.     

基于大数据的伪基站准实时监控方法的研究

基于大数据分析对伪基站的监测进行了更进一步的研究,对目前流动式伪基站研发了手机APP快速跟踪定位,提出全新的监测和治理的新方法。依托大数据分析平台,建立了伪基站准实时监控及分析的应用,为伪基站排查工作的常态化奠定基础。通过对信令数据的分析,实现对伪基站的准实时定位以及伪基站移动轨迹的描绘,同时根据伪基站的移动轨迹确定其活动规律及与伪基站具有相同活动规律的伪基站使用者的移动号码信息,从而获取疑似伪基站使用者的手机号码信息,提升了用户感知。     

Hybrid Sensor Calibration Scheme for Mobile Crowdsensing–Based City‐Scale Environmental Measurements

In this paper, we propose a hybrid sensor calibration scheme for mobile crowdsensing applications. As the number of newly produced mobile devices containing embedded sensors continues to rise, the potential to use mobile devices as a sensor data source increases. However, because mobile device sensors are generally of a lower performance and cost than dedicated sensors, sensor calibration is crucial. To enable more accurate measurements of natural phenomena through the use of mobile device sensors, we propose a hybrid sensor calibration scheme for such sensors; the scheme makes use of mobile device sensors and existing sensing infrastructure, such as weather stations, to obtain dense data. Simulation results show that the proposed scheme supports low mean square errors. As a practical application of our proposed scheme, we built a temperature map of a city using six mobile phone sensors and six reference sensors. Thanks to the mobility of the sensors and the proposed scheme, our map presents more detailed information than infrastructure‐based measurements.     

Optimal convergence rates of high order Parzen windows with unbounded sampling

High order Parzen windows are considered with data drawn from unbounded sampling processes. Convergence analysis is established by imposing a moment hypothesis on the unbounded sampling outputs and some decay conditions on the marginal distributions. Our estimate of convergence rate is consistent with the previous result with bounded sampling.     

Multifunctional Self-Charging Electrochromic Supercapacitors Driven by Direct-Current Triboelectric Nanogenerators

Electrochromic supercapacitor devices (ESCDs) are highly promising for energy-saving applications or smart windows, whereas they still require electrical energy inputs. In this study, a self-charging ESCD (SC-ESCD) based on the ESCD and a sliding-mode direct-current triboelectric nanogenerators is successfully proposed. The SC-ESCD cannot merely convert mechanical sliding kinetic energy into electrical energy and store the electricity in electrochromic supercapacitors but can also show optical responses to the mechanical sliding motions. The prominent electrochemical performances of the SC-ESCD are confirmed by the high areal capacitance (15.2 mF cm⁻² at 0.1 mA cm⁻²) and stable cycling performance (99% for 5000 cycles). Besides, it can be prepared into arbitrary characters or patterns to adapt to various applications. The study demonstrates a potential approach to develop multifunctional self-charging power sources which combine energy harvesting, energy storage, and electrochromic functions.     

我国移动电话资费水平分析（下）

通过对国外移动电话资费的特点及水平的介绍，分析我国移动资费的结构和水平，提出资费调整的建议。