Energy-Secrecy Trade-offs for Wireless Communication

This chapter investigates the secrecy-energy trade-offs for communication in wireless networks. It is shown that privacy requirements for applications such as image or video transmissions do not require perfect secrecy, and the level of privacy can be quantified using a Rate-Distortion metric. Using information theoretic analysis, the chapter formulates analytic secrecy trade-offs for various communication channel models. In particular we analyze the advantage of partial secrecy for the Gaussian and Rayleigh fading channel models and the MIMO channel. The impact of secrecy requirements and the inherent secrecy-energy-connectivity trade-offs are also analyzed for networks of wireless nodes

Object Tracking and Detecting Based on Adaptive Background Subtraction

AbstractA tracking algorithm based on adaptive background subtraction about the video detecting and tracking moving objects is presented in this paper. Firstly, we use median filter to achieve the background image of the video and denoise the sequence of video. Then we use adaptive background subtraction algorithm to detect and track the moving objects. Adaptive background updating is also realized in this paper. Finally, we improve the accuracy of tracking through open operation. The simulation results by MATLAB show that the adaptive background subtraction is useful in both detecting and tracking moving objects, and background subtraction algorithm runs more quickly

As influências do inglês na aprendizagem do português por estudantes chineses

O objetivo do presente trabalho é identificar as relações entre a aprendizagem do inglês e a aprendizagem do português por estudantes universitários chineses. A situação em que os mesmos estudam estas duas línguas no mesmo período é, de facto, bastante comum e clarificar as relações e as influências que a aprendizagem do inglês tem na aprendizagem do português ajuda os estudantes chineses a estudarem mais eficientemente o português e diminuir as confusões possíveis. Partindo dos conceitos clássicos da linguística aplicada, apresenta-se as teorias e metodologia envolvidos no presente trabalho. Depois da introdução e do enquadramento teórico, procede-se à apresentação de um questionário concebido e desenhado especialmente para o tema. Segundo os dados recolhidos pelo questionário, as dificuldades e confusões que os estudantes chineses de português têm na aprendizagem do português e do inglês ficam claramente identificadas. Através da análise dos dados, resume-se os problemas que os estudantes chineses enfrentam quando tratam das relações entre a aprendizagem do inglês e a aprendizagem de português, e são também identificadas as influências positivas do inglês que podem facilitar a aprendizagem do português. Complementando estes dados com as teorias linguísticas de referência, sugere-se, por fim, estratégias para resolver este tipo de interferência e melhorar a eficiência na aquisição da língua portuguesa.The aim of the present work is to identify the relationship between the learning of English and the learning of Portuguese by Chinese university students. Because the situation in which they study both languages in the same period is very common and clarifying the relationships and influences that learning English has on learning Portuguese helps Chinese students to study Portuguese more efficiently and reduce possible confusion.We start from the classic concepts of applied linguistics, presenting the theories and methodology involved in this work. After the introduction of the theoretical framework, a presentation of the questionnaire designed especially for the theme is made. According to the data collected by the questionnaire, the confusions that Chinese Portuguese students and the senses they have in learning Portuguese and English are clearly shown. Through analyzing the data, the problems that Chinese students have when dealing with the relationship between English learning and Portuguese learning are summarized, as well as the positive influences of English that can be used in learning Portuguese. Combining with linguistic theories, ways are designed to solve problems and increase the efficiency of learning the Portuguese language.This study is based on considerations of applied linguistics, especially the teaching and acquisition of Portuguese. In this sense, one can take advantage of the contrastive analysis between the two languages to promote and inherit Portuguese.Mestrado em Português Língua Estrangeira/Língua Segund

The First Verification Test of Space-Ground Collaborative Intelligence via Cloud-Native Satellites

Recent advancements in satellite technologies and the declining cost of access to space have led to the emergence of large satellite constellations in Low Earth Orbit. However, these constellations often rely on bent-pipe architecture, resulting in high communication costs. Existing onboard inference architectures suffer from limitations in terms of low accuracy and inflexibility in the deployment and management of in-orbit applications. To address these challenges, we propose a cloud-native-based satellite design specifically tailored for Earth Observation tasks, enabling diverse computing paradigms. In this work, we present a case study of a satellite-ground collaborative inference system deployed in the Tiansuan constellation, demonstrating a remarkable 50\% accuracy improvement and a substantial 90\% data reduction. Our work sheds light on in-orbit energy, where in-orbit computing accounts for 17\% of the total onboard energy consumption. Our approach represents a significant advancement of cloud-native satellite, aiming to enhance the accuracy of in-orbit computing while simultaneously reducing communication cost.Comment: Accepted by China Communication

Sketch-based Video Object Segmentation: Benchmark and Analysis

Reference-based video object segmentation is an emerging topic which aims to segment the corresponding target object in each video frame referred by a given reference, such as a language expression or a photo mask. However, language expressions can sometimes be vague in conveying an intended concept and ambiguous when similar objects in one frame are hard to distinguish by language. Meanwhile, photo masks are costly to annotate and less practical to provide in a real application. This paper introduces a new task of sketch-based video object segmentation, an associated benchmark, and a strong baseline. Our benchmark includes three datasets, Sketch-DAVIS16, Sketch-DAVIS17 and Sketch-YouTube-VOS, which exploit human-drawn sketches as an informative yet low-cost reference for video object segmentation. We take advantage of STCN, a popular baseline of semi-supervised VOS task, and evaluate what the most effective design for incorporating a sketch reference is. Experimental results show sketch is more effective yet annotation-efficient than other references, such as photo masks, language and scribble.Comment: BMVC 202

Resource-efficient In-orbit Detection of Earth Objects

With the rapid proliferation of large Low Earth Orbit (LEO) satellite constellations, a huge amount of in-orbit data is generated and needs to be transmitted to the ground for processing. However, traditional LEO satellite constellations, which downlink raw data to the ground, are significantly restricted in transmission capability. Orbital edge computing (OEC), which exploits the computation capacities of LEO satellites and processes the raw data in orbit, is envisioned as a promising solution to relieve the downlink burden. Yet, with OEC, the bottleneck is shifted to the inelastic computation capacities. The computational bottleneck arises from two primary challenges that existing satellite systems have not adequately addressed: the inability to process all captured images and the limited energy supply available for satellite operations. In this work, we seek to fully exploit the scarce satellite computation and communication resources to achieve satellite-ground collaboration and present a satellite-ground collaborative system named TargetFuse for onboard object detection. TargetFuse incorporates a combination of techniques to minimize detection errors under energy and bandwidth constraints. Extensive experiments show that TargetFuse can reduce detection errors by 3.4 times on average, compared to onboard computing. TargetFuse achieves a 9.6 times improvement in bandwidth efficiency compared to the vanilla baseline under the limited bandwidth budget constraint.Comment: Accepted by IEEE INFOCOM 2024-IEEE Conference on Computer Communication

Association of Lifestyle Factors with Multimorbidity Risk in China: A National Representative Study

Multimorbidity significantly impacts health, well-being, and the economy; therefore, exploring notable factors associated with multimorbidity across all age groups is critical. For this investigation, we focused on the relationship between four lifestyle factors and multimorbidity risk. We recruited 11,031 Chinese citizens aged ≥ 12 years from 31 provinces between July 2021 and September 2021 using a quota sampling strategy to ensure that the socioeconomic characteristics (sex, age, rural–urban distribution) of those participating in this research were representative of national demographics. In the first stage, multivariable logistic regression models were utilized as a means of investigating the relationship between lifestyle factors and multimorbidity. Then, a multinomial logistic regression model was used with the aim of examining the Healthy Lifestyle Profile (HLP) related to the number of chronic diseases. Multivariable logistic regression models assessed the interaction effects and joint association among the four lifestyle factors. Overall, 18% of the participants had at least one disease, and 5.9% had multimorbidity. Approximately two-thirds of the participants were physically inactive, 40% had consumed alcohol, 39% were underweight or overweight, and 20% were or had been smokers. Participants who maintained one HLP showed a 34% lower multimorbidity risk (adjusted OR, 0.66; 95% CI, 0.48 to 0.92), while participants who maintained 4 HLP showed a 73% lower multimorbidity risk (adjusted OR, 0.27; 95% CI, 0.17 to 0.43), as compared to those who had 0 HLP. The joint association analysis revealed that participants with all four healthy lifestyle factors had 0.92 times lower odds of multimorbidity (95% CI: 0.90, 0.94) in comparison with the all-unhealthy reference cluster. Notably, individuals with a combination of healthy smoking status and healthy body weight had the highest minimized odds of multimorbidity (OR: [0.92], 95% CI: 0.91, 0.94). Common lifestyle habits, alone or in combination, are associated with multimorbidity risk. This study provides insights for public health programs to promote a healthy lifestyle at a younger age and to alleviate multimorbidity risk in older people