Towards Efficient Record and Replay: A Case Study in WeChat

WeChat, a widely-used messenger app boasting over 1 billion monthly active users, requires effective app quality assurance for its complex features. Record-and-replay tools are crucial in achieving this goal. Despite the extensive development of these tools, the impact of waiting time between replay events has been largely overlooked. On one hand, a long waiting time for executing replay events on fully-rendered GUIs slows down the process. On the other hand, a short waiting time can lead to events executing on partially-rendered GUIs, negatively affecting replay effectiveness. An optimal waiting time should strike a balance between effectiveness and efficiency. We introduce WeReplay, a lightweight image-based approach that dynamically adjusts inter-event time based on the GUI rendering state. Given the real-time streaming on the GUI, WeReplay employs a deep learning model to infer the rendering state and synchronize with the replaying tool, scheduling the next event when the GUI is fully rendered. Our evaluation shows that our model achieves 92.1% precision and 93.3% recall in discerning GUI rendering states in the WeChat app. Through assessing the performance in replaying 23 common WeChat usage scenarios, WeReplay successfully replays all scenarios on the same and different devices more efficiently than the state-of-the-practice baselines

Evaluation of cloned cells, animal model, and ATRA sensitivity of human testicular yolk sac tumor

The testicular yolk sac tumor (TYST) is the most common neoplasm originated from germ cells differentiated abnormally, a major part of pediatric malignant testicular tumors. The present study aimed at developing and validating the in vitro and vivo models of TYST and evaluating the sensitivity of TYST to treatments, by cloning human TYST cells and investigating the histology, ultra-structure, growth kinetics and expression of specific proteins of cloned cells. We found biological characteristics of cloned TYST cells were similar to the yolk sac tumor and differentiated from the columnar to glandular-like or goblet cells-like cells. Chromosomes for tumor identification in each passage met nature of the primary tumor. TYST cells were more sensitive to all-trans-retinoic acid which had significantly inhibitory effects on cell proliferation. Cisplatin induced apoptosis of TYST cells through the activation of p53 expression and down-regulation of Bcl- expression. Thus, we believe that cloned TYST cells and the animal model developed here are useful to understand the molecular mechanism of TYST cells and develop potential therapies for human TYST

Sensor-network-based mobile home care system

The whole world faces problems of population aging. Having seniors at home alone would make most people worry, as one cannot keep a close eye on them all day. Worse still, medical plans for elderly people are so mass-produced that they cannot deliver e®ective results. The demand for low-cost geriatric care systems is high. This project included work done in the ¯eld of teleoperated mobile robotic home care system. A mobile robot prototype with visual capability and communication capabilities actualized via sensor networks was designed and implemented to realize two functions: real-time health monitoring and telepresence. With the aid of a wireless biosensor, the system can provide solutions for re- mote monitoring of real-time electrocardiogram (ECG) signals. Equipped with a rotatable video camera and a wireless communication device, the robot allows virtual visits for remote parties. It can be guided from any- where with Internet connection and provides live images. Moreover, our system can be applied to act as a mobile surveillance system to secure one's residence. The hardware platform was constructed based on an ARM9-based micro- controller. Peripheral functional modules were built up and integrated to- gether. An embedded real-time software and a PC-based control software, which collaboratively control the home care system and provide live display of video stream, were developed. Testing shows the prototype built in this project possess desired capability and reliability to function properly.Bachelor of Engineerin

Experimental study of the D-OSKIL mechanism for controlling the stick-slip oscillations in a drilling laboratory testbed

International audienceThe presence of harmful stick-slip oscillations in oil well drillstrings has attracted the attention of the control community in recent years. The control law named D-OSKIL mechanism which uses the weight on the bit (WoB) force as an additional control variable to extinguish limit cycles has been investigated. This paper reports experimental implementation of such a mechanism, in a laboratory testbed. We also provide details of the experimental process and the obtained drilling performance. Results show that the stick-slip oscillations can be effectively suppressed by this mechanism

Federated learning based proactive content caching in edge computing

Content caching is a promising approach in edge computing to cope with the explosive growth of mobile data on 5G networks, where contents are typically placed on local caches for fast and repetitive data access. Due to the capacity limit of caches, it is essential to predict the popularity of files and cache those popular ones. However, the fluctuated popularity of files makes the prediction a highly challenging task. To tackle this challenge, many recent works propose learning based approaches which gather the users' data centrally for training, but they bring a significant issue: users may not trust the central server and thus hesitate to upload their private data. In order to address this issue, we propose a Federated learning based Proactive Content Caching (FPCC) scheme, which does not require to gather users' data centrally for training. The FPCC is based on a hierarchical architecture in which the server aggregates the users' updates using federated averaging, and each user performs training on its local data using hybrid filtering on stacked autoencoders. The experimental results demonstrate that, without gathering user's private data, our scheme still outperforms other learning-based caching algorithms such as m-epsilon-greedy and Thompson sampling in terms of cache efficiency

Thermoelectric properties of In-Hg co-doping in SnTe: Energy band engineering

Synergistic effect of band convergence and resonant level could be manipulated in SnTe by co-doping In and Hg, leading to a potential thermoelectric performance enhancement in a much wider temperature range. In this work we carefully investigated thermoelectric properties of the In-Hg co-doped SnTe, synthesized by a hot pressing method. With this co-doping the Seebeck coefficients of the co-doped samples were greatly improved (over 50 μVK−1) at the room temperature. Although power factors of the In-Hg co-doped SnTe were also able to be optimized, the peak ZT (0.9 at 850 K in Sn0.98Bi0.02Te-1%HgInTe2), however, is not high enough when comparing to other co-doped SnTe systems. This may be caused by the relatively high lattice thermal conductivity. An apparent competition between band convergence doping and resonant level doping was observed in our experiment. The results suggest that band engineering via co-doping should be further understood in order to optimize the thermoelectric properties inside the material system

MEMS-based fabrication of high-performance inductors with back hollow structure and ferromagnetic film

International audienceThe development of novel on-chip device techniques is attracting more and more interest because of the increasing demand for communication electronics, wearable devices and Internet of Things (IoT) with features of low power consumption, high frequency-response, small size, fast transmission rate, and low-costs in the lab-on-chip field. This letter presents the high frequency performance enhancement of on-chip inductors by the use of a back hollow structure filled with CoFeB/ZnO/CoFeB thin ferromagnetic layers. The magnetization dynamic response of this ferromagnetic stacks deposited by RF-magnetron sputtering were investigated. The inductance increases by 41.2%–70.6% between 0.1 and 8 GHz reaching 70.6% at 6.9 GHz. Q-factor increases also in a range of 3% to 18% between 0.1 and 3.8 GHz and reach 18% at 1.5 GHz. The equivalent circuit model and simplified physical model of the individual inductor were established and used to model and describe the parameters of inductor, such as the inductance and Q-factor as function of frequency. The results show the potential for application of the back hollow structure inductors with ferromagnetic thin film in RF circuits