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- ItemTopic analysis in news via sparse learning: a case study on the 2016 US presidential elections(2017-06) Ghaoui, Laurent El; Calafiore, Giuseppe CTextual data such as tweets and news is abundant on the web. However, extracting useful information from such a deluge of data is hardly possible for a human. In this paper, we discuss automated text analysis methods based on sparse optimization. In particular, we use sparse PCA and Elastic Net regression for extracting intelligible topics from a big textual corpus and for obtaining time-based signals quantifying the strength of each topic in time. These signals can then be used as regressors for modeling or predicting other related numerical indices. We applied this setup to the analysis of the topics that arose during the 2016 US presidential elections, and we used the topic strength signals in order to model their influence on the election polls.
- ItemGastric cancer: epidemiology, biology, and prevention: a mini review(2018) Kiara Lyons; Linh Le; Yen Pham; Claire Borron; Jong Y. Park; Chi Tran; Thuan Tran; Huong Tran; Khanh Vu; Cuong Do; Claudio Pelucchi; Carlo La Vecchia; Janice Zgibor; Paolo Boffetta; Hung LuuGastric cancer is one of the most common causes of cancer-related mortality worldwide. The objective of this article is to review the epidemiology and biology of gastric cancer risk. This literature review explores the biological, clinical, and environmental factors that influence the rates of this disease and discuss the different intervention methods that may not only increase the awareness of gastric cancer but also increase screening in efforts to reduce the risk of gastric cancer. Helicobacter pylori infection is the primary risk factor for gastric cancer. Additional risk factors include geographical location, age, sex, smoking, socioeconomic status, dietary intake, and genetics. Primary and secondary prevention strategies such as dietary modifications and screenings are important measures for reducing the risk of gastric cancer. Interventions, such as H. pylori eradication through chemoprevention trials, have shown some potential as a preventative strategy. Although knowledge about gastric cancer risk has greatly increased, future research is warranted on the differentiation of gastric cancer epidemiology by subsite and exploring the interactions between H. pylori infection, genetics, and environmental factors. Better understanding of these relationships can help researchers determine the most effective intervention strategies for reducing the risk of this disease.
- ItemA Quantitative Analysis of the Effect of Human Detection and Segmentation Quality in Person Re-identification Performance(2019) Binh Nguyen; Quan Nguyen; Lan Le; Thuy Pham; Nam PhamPerson re-identification, a problem of person identity association across camera views at different locations and times, is the second step in two-steps system for automatic video surveillance: person detection, tracking and person reidentification. However, most of the reported person Re-ID methods deal with the human regions of interest (ROIs) which are extracted manually with well-aligned bounding boxes. They mainly focus on designing discriminative feature descriptors and relevant metric learning on these manually-cropped human ROIs. This paper aims to answer two questions: (1) Do human detection and segmentation affect the performance of person reidentification?; (2) How to overcome the effect of human detection and segmentation with the state-of-the-art method for person re-identification? To answer these two questions, quantitative evaluations have been performed for both single-shot and multishot scenarios of person re-identification. Different state-of-the-art methods for human detection and segmentation have been evaluated on two benchmark datasets (VIPeR and PRID2011). The obtained results allow us to give some suggestions for developing fully automatic video surveillance systems.
- ItemQoE-Aware Video Streaming over HTTP and Software Defined Networking(2019) Pham, Hong Thinh; Nguyen, Thanh Dat; Pham, Ngoc Nam; Nguyen, Huu Thanh; Truong, Thu HuongDue to the increase in video streaming traffic over the Internet, more innovative methods are in demand for improving both the Quality of Experience (QoE) of users and the Quality of Service (QoS) of providers. In recent years, HTTP Adaptive Streaming (HAS) has received significant attention from both industry and academia based on its impacts in the enhancement of media streaming services. However, HAS-alone cannot guarantee a seamless viewing experience, since this highly relies on the Network Operators’ infrastructure and evolving network conditions. Along with the development of future Internet infrastructure, SoftwareDefined Networking (SDN) has been researched and newly implemented as a promising solution in improving the services of different Internet layers. In order to enhance the quality of video delivery, we try to combine the above two technologies, which has not been well-studied in academia. In this paper, we present a novel architecture incorporating bitrate adaptation and dynamic route allocation. At the client side, the adaptation logic of VBR videos streaming is built based on the MPEG-DASH standard. On the network side, an SDN controller is implemented with several routing strategies on top of the OpenFlow protocol. Our experimental results show that the proposed solution enhances at least 38% up to 185% in terms of average bitrate in comparison with some existing solutions as well as achieves a smoother viewing experience than the traditional Internet.
- ItemScalable 360 Video Streaming using HTTP/2(2019) Nguyen, Duc; Hoang, Van Trung; Hoang, Le Dieu Huong; Truong, Thu Huong; Pham, Ngoc Nam; Truong, Cong Thang360-degree video is the main content type of Virtual Reality, providing users with an immersive viewing experience. In this paper, we propose a novel adaptation method for 360-degree video streaming over HTTP/2, which can provide a high viewing experience to users under time-varying network conditions and time-varying user head movements. The proposed method utilizes Scalable Video Coding to solve the trade-off between network adaptivity and user adaptivity. An optimal tile layer selection algorithm is provided. To cope with sudden throughput drops, the delivery of late layers is terminated using HTTP/2’s stream termination feature. Also, a tile layer updating scheme is proposed to deal with viewport estimation errors. Experimental results show that the proposed method can improve the average bitrate of viewport by 16-17% compared to a reference method.
- ItemPrevalence and Pattern of Congenital Anomalies in a Tertiary Hospital in Central Vietnam(2019) Hoang, Thi Nam Giang; Susanne Bechtold-Dalla Pozza; Sarah Ulrich; Le, Khac Linh; Hoang, Thi TranBackground: Burden and pattern of congenital anomalies are insufficiently reported in Vietnam. This study aims to determine the prevalence and pattern of congenital anomalies in neonates in a tertiary hospital in central Vietnam. Methods: A prospective cross-sectional study recruited all newborns with congenital anomalies in Da Nang Hospital for Women and Children—where nearly 60% neonates in the city are delivered. Results: Over a 1-year period, 551 out of 14 335 registered live births were found to have congenital anomalies, equivalent to an overall prevalence of 384.4 per 10 000 live births. Congenital heart defects were the most common type (52.3%) with a prevalence of 200.9 per 10 000 live births, followed by anomalies of musculoskeletal system, digestive system. Conclusions: This study revealed a high prevalence of congenital anomalies with the most common type being congenital heart defects in central Vietnam compared to both higher income countries and resource-limited settings.
- ItemUsage and Impact of Information and Communication Technologies in Healthcare Delivery(2019) Lu Kong; Hessam Sadatsafavi; Rohit VermaThis paper discusses two aspects of the use of information and communication technologies (ICTs) in healthcare: first, the prevalence of using tables and laptop computers by physicians during clinical visits and, second, the growing trend of using such technologies for delivering healthcare remotely. Phone interview data from a random sample of 1,600 individuals with diverse sociodemographic characteristics were collected. Openended and structured questionnaires were used to elicit relevant information, which was analyzed using qualitative content analysis and logistic regression models. Results suggest that, as computer literacy is increasing within the general population and caregivers’ skills in using computer technology is improving, patients are welcoming the use of ICTs in healthcare. The analysis also showed that age together with enabling factors, such as income and education, are substantial barriers to the use of remote care services, even more important than gender, place of residence, race or ethnicity, and care need. Income and education do not influence the acceptance of ICT use by doctors during visits. Females, older participants, and those with more children in the household showed more resistance to the use of ICT in healthcare. At the same time, the depersonalization of interactions with caregivers was a critical concern identified related to the use of ICT in healthcare.
- ItemThe association between birth order and childhood brain tumors: a systematic review and meta-analysis(2019) Nguyen, V. Mai; Tran, T. Mo; Tran, T. D. Chi; Tran, H. Quang; Tuong, T. V. Thuy; Phung, N. Lam; Vu, X. Huyen; Le, C. Linh; Boffetta, Paolo; Luu, N. HungThe incidence of childhood brain tumors (CBT) has increased worldwide, likely resulting from the improvements of early diagnostics. We conducted a systematic review and meta-analysis to clarify the association between birth order and CBT. We followed established guidelines to systematically search Ovid Medline, PubMed, and the Cochrane Library for English language studies, published before March 2018. Quality assessment was performed using the Newcastle–Ottawa Scale. Meta-analysis provided pooled risk estimates and their 95% confidence intervals (CIs) for birth order and CBT. We identified 16 case–control studies with a total sample of 32 439 cases and 166 144 controls and three prospective cohort studies (i.e. 4515 incident cases of CBTs among 5 281 558 participants). Compared with the first birth order, the meta-odds ratio for the second birth order in case–control studies was 1.04 (95% CI: 1.01–1.07), that for the third birth order was 0.98 (95% CI: 0.90–1.06), and that for fourth order was 0.85 (95% CI: 0.78–0.92). The meta-hazard ratio for second or higher birth order compared with first birth order in cohort studies was 1.00 (95% CI: 0.96–1.05). We found no association between birth order and CBT in both case–control and cohort study designs; the small association observed for the fourth birth order deserves further consideration.
- ItemLifetime Drinking Trajectories and Nonfatal Acute Myocardial Infarction(2019) Marcia Russell; Amy Z. Fan; Jo L. Freudenheim; Joan Dorn; Maurizio TrevisanBackground: The relation of lifetime drinking trajectories to coronary heart disease is not well understood. Methods: Cases hospitalized for a nonfatal acute myocardial infarction (AMI) and healthy population-based controls matched on age and sex completed a physical examination and an interview covering known AMI risk factors and a detailed lifetime drinking history. Distinct lifetime drinking trajectories based on ounces of ethanol consumed per decade between ages 10 and 59 years were derived and characterized according to lifetime drinking patterns associated with each. Sex-specific multiple logistic regression analyses were conducted to estimate AMI risk among participants who never drank regularly compared to lifetime drinking trajectories and risk associated with distinct trajectories among former and current drinkers. Results: Two lifetime drinking trajectories were derived, early peak and stable. Early peak trajectories were characterized by an earlier onset of regular drinking, less frequent drinking, more drinks per drinking day, fewer total drinks, more frequent drunkenness per drinking year, and reduced alcohol intake or abstention by middle age. Never drinking regularly, reported by significantly more women than men, was associated with significantly higher AMI risk than stable lifetime drinking trajectories among men and in the sex-combined analysis of former drinkers only. Compared to a stable lifetime drinking trajectories, early peak trajectories were associated with significantly higher AMI risk among male former drinkers, among sex-combined former drinkers, and among female current drinkers. Conclusions: Epidemiological studies of alcohol and health in populations over age 35 may have underestimated the impact of heavy episodic drinking during adolescence and emerging adulthood on the cardiovascular system.
- ItemSDN – based Dynamic Bandwidth Allocation for Multiple Video-on-Demand Players over HTTP(2019) Pham, Hong Thinh; Pham, Ngoc Nam; Nguyen, Huu Thanh; Truong, Thu HuongThis nowadays, HTTP adaptive streaming (HAS) has been becoming the de-factor standard for video streaming over the multimedia network. However, HAS-alone cannot guarantee a seamless viewing experience, the adaptation of HAS in the management network faces a big challenge because of purely client-driven approaches which lead to unfair competition of available bandwidth resource when multiple bitrate-adaptive players share the same bottleneck network link. At that time, each HAS client tries independently to maximize its own bandwidth sharing, which leads to the competition of network resources among clients causing greatly reduced QoE (Quality of Experience) of end users. This competition will affect negatively several main metrics for each video player: fairness, efficiency, and stability. In this paper, we propose a scheme of bitrate adaptation for the HAS system combined with a Software Defined Networking (SDN)-based dynamic resource allocation, which aims to improve the quality of experience among competing clients. Our experiment results show that the proposed method significantly outperforms the conventional method on all the key QoE parameters under several scenarios.
- ItemAn LSTM-based Approach for Overall Quality Prediction in HTTP Adaptive Streaming(2019-04) Huyen Tran; Duc Nguyen; Nam Pham; Thang Truong; Duong NguyenHTTP Adaptive Streaming (HAS) has become a popular solution for multimedia delivery nowadays. In HAS, video quality is generally varying in each streaming session. Therefore, a key question in HTTP Adaptive Streaming is how to evaluate the overall quality of a streaming session. In this paper, we propose a machine-learning approach for overall quality prediction in HTTP Adaptive Streaming. In the proposed approach, each segment is represented by four features segment quality, stalling durations, content characteristics, and padding. The features are fed into a Long Short-Term Memory (LSTM) network that is capable of exploring temporal relations between segments. The overall quality of the streaming session is predicted from the outputs of the LSTM network using a linear regression module. Experiment results show that the proposed approach is effective in predicting the overall quality of streaming sessions. Also, it is found that our proposed approach outperforms four existing approaches.
- ItemQuyền Văn Minh and the Birth of Vietnamese Jazz(2019-05-30) Stan B. H. Tan-Tangbau; Quyen Van MinhWritten in the form of a collaborative narrative, this paper is an account of the live concert at the Hà Nội Opera House on 12 April 1994, an important chapter in the story of Quyền Văn Minh and jazz in modern day Vietnam. Quyền Văn Minh had earlier brought jazz to the public sphere in socialist Vietnam with two groundbreaking concerts in 1988 and 1989. For this solo concert in 1994, Quyền Văn Minh premiered three of his original jazz compositions. Each tune was inspired by the sounds of different ethnic folk music Minh heard during his travels as a musical cadre in socialist Vietnam during the 1970s and 1980s. Minh wrote original melodies and made room for improvisation in his compositions to tell the stories he had in mind with his music. With this performance, Minh stamped his mark as the pioneer bona fide jazz musician in the early Đổi Mới years of Vietnam. More significantly, a new genre of sounds in the form of Vietnamese jazz was born that evening. This paper is part of a larger book project on the life story of Quyền Văn Minh and the story of jazz in Vietnam under the socialist state.
- ItemA Subjective Study on User Perception Aspects in Virtual Reality(2019-08-16) Huyen Tran; Nam Pham; Cuong Pham; Yong Ju Jung; Thang TruongThree hundred and sixty degree video is becoming more and more popular on the Internet. By using a Head-Mounted Display, 360-degree video can render a Virtual Reality (VR) environment. However, it is still a big challenge to understand Quality of Experience (QoE) of 360-degree video since user experience during watching 360-degree video is a very complex phenomenon. In this paper, we aim to investigate four QoE aspects of 360-degree video, namely, perceptual quality, presence, cybersickness, and acceptability. In addition, four key QoE-affecting factors of encoding parameters, content motion, rendering device, and rendering mode are considered in our study. To the best of our knowledge, this is the first work that covers a large number of factors and QoE aspects of 360-degree video. In this study, a subjective experiment is conducted using 60 video versions generated from three original 360-degree videos. Based on statistical analysis of the obtained results, various findings on the impacts of the factors on the QoE aspects are provided. In particular, regarding the impacts of encoding parameters, it is found that the difference of QoE is negligible between video versions encoded at 4 K and 2.5 K resolutions. Also, it is suggested that 360-degree video should not be encoded at HD resolution or lower when watching in VR mode using Head Mounted Display. In addition, the bitrate for good QoE varies widely across different video contents. With respect to the content motion factor, its impact is statistically significant on the perceptual quality, presence, and cybersickness. In a comparison of two rendering device sets used in this study, there is no statistically significant difference found for the acceptability and cybersickness. However, the differences of the perceptual quality and presence are indicated to be statistically significant. Regarding the rendering mode, a comparison between VR and non-VR modes is also conducted. Although the non-VR mode always achieves higher perceptual quality scores and higher acceptability rates, more than half of the viewers prefer the VR mode to the non-VR mode when watching versions encoded at the resolutions of fHD or higher. By contrast, the non-VR mode is preferred at the HD resolution.
- ItemAn Efficient QoE-Aware HTTP Adaptive Streaming over Software Defined Networking(2020) Thinh Pham; Dat Nguyen; Nam Pham; Thanh Nguyen; Hien Nguyen; Huong TruongDue to the increase in video streaming traffic over the Internet, more innovative methods are in demand for improving both Quality of Experience (QoE) of users and the Quality of Service (QoS) of providers. In recent years, HTTP Adaptive Streaming (HAS) has received significant attention from both industry and academia based on its impacts on the enhancement of media streaming services. However, HAS alone cannot guarantee a seamless viewing experience, since this highly relies on the Network Operators’ infrastructure and evolving network conditions. Along with the development of future Internet infrastructure, Software-Defined Networking (SDN) has been researched and newly implemented as a promising solution in improving services of different Internet layers. In this paper, we present a novel architecture incorporating bitrate adaptation and dynamic route allocation. On the client side, the adaptation logic of VBR video streaming is built based on the MPEGDASH standard. On the network side, an SDN controller is implemented with several routing strategies on top of the OpenFlow protocol. Our experimental results show that the proposed solution enhances at least 38% up to 185% in terms of average bitrate in comparison with some existing solutions as well as achieves a better viewing experience than the traditional Internet.
- ItemA Privacy-Preserving Framework for Surveillance Systems(2020) Kok-Seng Wong; Tu Nguyen; Anuar Maratkhan; M. Fatih, DemirciThe ability to visually track people present in the scene is essential for any surveillance system. However, the widespread deployment and increased advancement of video surveillance systems have raised awareness of privacy to the public, i.e., human identity in the videos. The existing indoor surveillance systems allow people to be watched remotely and recorded continuously but do not prevent any party from viewing activities and collecting personal visual information of people in the videos. Because of this problem, we propose a privacy-preserving framework to provide each user (e.g., parents) with a personalized video where the user sees only selected target subjects (e.g., child, teacher, and intruder) while other faces are dynamically masked. The primary services in our framework consist of a video streaming service and a personalized service. The video streaming service is responsible for detecting, segmenting, recognizing, and masking face images of the human subjects in the video. Notably, it classifies human subjects into insider and outsider classes and then applies the de-identification (i.e., masking) to those in the insider class, including the target subjects. Subsequently, the personalized service receives the visual information (i.e., masked and unmasked faces) from the streaming service and processes it at the user’s mobile device. The output is then a personalized video for each user. For security reasons, we require surveillance videos stored in the cloud in an encrypted form. To ensure an individual remains anonymous in a group, we propose a dynamic masking approach to mask the human subjects in the video. Our framework can deliver both reliable visual privacy protection and video utility. For instance, users can have confidence that their target subjects are anonymized in other views. To utilize the personalized video, users can use analytics software installed on their mobile devices to analyze the activities of their target subjects.
- ItemDevelopment and validation of the pick-up service quality scale of the buy-online-pick-up-in-store service(2020) Yeonjoo Lee; Sunmee Choi; Joy M. FieldBuy-Online-Pick-up-in-Store (BOPS) service is a popular omnichannel retail initiative, intended to enhance the convenience of online customers. Focusing on the pick-up (PU) stage of BOPS service, we develop a comprehensive scale (BOPS-PU-QUAL) for its quality perceived by customers. A multi-step scale development procedure involving one qualitative and two quantitative studies resulted in a scale consisting of 16 items under four dimensions. Service effectiveness is found to be the strongest influencer on quality perceptions of BOPS-PU, followed by problem handling, ease of access, and item quality. A structural equation analysis reveals that BOPS-PU-QUAL perceptions positively affect customers’ behavioral intentions towards the brand’s BOPS service, with the relationship fully mediated by satisfaction with BOPS. This study contributes to omnichannel service quality research by identifying the critical quality dimensions of BOPS pick-up service that reflect the uniqueness of BOPS customers. These findings help practitioners realize the importance of managing BOPS-PU service quality and provide practical guidance.
- ItemOxidative Stress by Ca2+ 1 Overload is Critical for Phosphate-Induced 2 Vascular Calcification(2020) Nguyen, Thi Nhung; Nguyen, Thi Tuyet; Ly, Da Dat; Xia, Jing-Bo; Qi, Xu-Feng; Lee, In-Kyu; Cha, Seung-Kuy; Park, Kyu-SangHyperphosphatemia is the primary risk factor for vascular calcification, which is closely associated with cardiovascular morbidity and mortality. Recent evidence showed that oxidative stress by high inorganic phosphate (Pi) mediates calcific changes in vascular smooth muscle cells (VSMCs). However, intracellular signalings responsible for Pi-induced oxidative stress remain unclear. Here, we investigated molecular mechanisms of Pi-induced oxidative stress related to intracellular Ca2+ ([Ca2+]i) disturbance, which is critical for the calcification of VSMCs. VSMCs isolated from rat thoracic aorta or A7r5 cells were incubated with a high Pi-containing medium. An extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin were activated by high Pi that was required for vascular calcification. High Pi upregulated expressions of type III sodium-phosphate cotransporters, PiT-1 and -2, and stimulated their trafficking to the plasma membrane. Interestingly, high Pi increased [Ca2+]i exclusively dependent on extracellular Na+ and Ca2+ as well as PiT 1/2 abundance. Furthermore, high Pi-induced plasma membrane depolarization is mediated by PiT-1/2. Pretreatment with verapamil, as a voltage-gated Ca2+ channel (VGCC) blocker, inhibited Pi-induced [Ca2+]i elevation, oxidative stress, ERK activation, and osteogenic differentiation. These protective effects were reiterated by extracellular Ca2+ free condition, intracellular Ca2+ chelation, or suppression of oxidative stress. Mitochondrial superoxide scavenger also effectively abrogated ERK activation and osteogenic differentiation of VSMCs by high Pi. Taken together, we suggest that high Pi activates depolarization-triggered Ca2+ influx via VGCC, and subsequent [Ca2+]i increase elicits oxidative stress and osteogenic differentiation. PiT-1/2 mediates Pi-induced [Ca2+]i overload and oxidative stress, but in turn, PiT-1/2 is upregulated by consequences of these alterations.
- ItemStability Properties of 1-Dimensional Hamiltonian Lattices with Non-analytic Potentials(2020) Bountis, Anastasios; Kaloudis, Konstantinos; Oikonomou, Thomas; Manda, M. Bertin; Skokos, CharalamposWe investigate the local and global dynamics of two 1-Dimensional (1D) Hamiltonian lattices whose inter-particle forces are derived from non-analytic potentials. In particular, we study the dynamics of a model governed by a “graphene-type” force law and one inspired by Hollomon’s law describing “work-hardening” effects in certain elastic materials. Our main aim is to show that, although similarities with the analytic case exist, some of the local and global stability properties of non-analytic potentials are very different than those encountered in systems with polynomial interactions, as in the case of 1D Fermi-Pasta-Ulam-Tsingou (FPUT) lattices. Our approach is to study the motion in the neighborhood of simple periodic orbits representing continuations of normal modes of the corresponding linear system, as the number of particles N and the total energy E are increased. We find that the graphene-type model is remarkably stable up to escape energy levels where breakdown is expected, while the Hollomon lattice never breaks, yet is unstable at low energies and only attains stability at energies where the harmonic force becomes dominant. We suggest that, since our results hold for large N, it would be interesting to study analogous phenomena in the continuum limit where 1D lattices become strings.
- ItemConstrained crystal growth during solidification of particles and splats in uniform droplet sprays(2020) Yiannos Ioannou; Hiroki Fukuda; Claus Rebholz; Yiliang Liao; Teiichi Ando; Charalabos C. DoumanidisUniform droplet spraying (UDS) is a novel process used to produce ideally narrow (mono-size) distributions of molten metal droplets for various applications. The crystallite size is a primary determinant of mechanical properties in solidified alloy deposits and thus in need of predictive modeling. This project reports on employing UDS as a paradigm for solidification modeling of mono-size solid droplets in an oil bath, as well as planar and globular splats on a cooling substrate, for magnesium alloys AZ91D and Mg97ZnY2. The model combines a nucleation and dendrite fragmentation description from solidification theory, with a framework for constrained growth of crystalline domains confined by adjacent developing ones. The latter is based on differential attributes of the dynamic temperature field during solidification, derived from semi-analytical expressions for the simple droplet and splat geometries above. The modeling results are validated against measured domain size distributions on section micrographs and found to be within a − 10% to + 14% estimation error range. Further improvement of the model via numerical thermal descriptions for off-line material design and optimization in additive manufacturing is discussed, along with its use as a real-time structural observer for closed-loop control based on temperature measurements in UDS-based processes.