34 results on '"Aaron Sun"'
Search Results
2. A Multi-Level Task Framework for Event Sequence Analysis
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Zinat, Kazi Tasnim, Sakhamuri, Saimadhav Naga, Chen, Aaron Sun, and Liu, Zhicheng
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Computer Science - Human-Computer Interaction - Abstract
Despite the development of numerous visual analytics tools for event sequence data across various domains, including but not limited to healthcare, digital marketing, and user behavior analysis, comparing these domain-specific investigations and transferring the results to new datasets and problem areas remain challenging. Task abstractions can help us go beyond domain-specific details, but existing visualization task abstractions are insufficient for event sequence visual analytics because they primarily focus on multivariate datasets and often overlook automated analytical techniques. To address this gap, we propose a domain-agnostic multi-level task framework for event sequence analytics, derived from an analysis of 58 papers that present event sequence visualization systems. Our framework consists of four levels: objective, intent, strategy, and technique. Overall objectives identify the main goals of analysis. Intents comprises five high-level approaches adopted at each analysis step: augment data, simplify data, configure data, configure visualization, and manage provenance. Each intent is accomplished through a number of strategies, for instance, data simplification can be achieved through aggregation, summarization, or segmentation. Finally, each strategy can be implemented by a set of techniques depending on the input and output components. We further show that each technique can be expressed through a quartet of action-input-output-criteria. We demonstrate the framework's descriptive power through case studies and discuss its similarities and differences with previous event sequence task taxonomies., Comment: Task Abstraction, Event Sequence Data
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- 2024
3. Task2Box: Box Embeddings for Modeling Asymmetric Task Relationships.
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Rangel Daroya, Aaron Sun, and Subhransu Maji
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- 2024
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4. COSE: A Consistency-Sensitivity Metric for Saliency on Image Classification.
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Rangel Daroya, Aaron Sun, and Subhransu Maji
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- 2023
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5. A Systematic Framework for Sentiment Identification by Modeling User Social Effects.
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Kunpeng Zhang, Yi Yang 0042, Aaron Sun, and Hengchang Liu
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- 2014
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6. Information Overload and Viral Marketing: Countermeasures and Strategies.
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Jiesi Cheng, Aaron Sun, and Daniel Zeng 0001
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- 2010
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7. Network-Based Analysis of Beijing SARS Data.
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Xiaolong Zheng 0001, Daniel Zeng 0001, Aaron Sun, Yuan Luo, Quanyi Wang, and Fei-Yue Wang 0001
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- 2008
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8. Discovering Trends in Collaborative Tagging Systems.
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Aaron Sun, Daniel Zeng 0001, Huiqian Li, and Xiaolong Zheng 0001
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- 2008
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9. High endogenous CCL2 expression promotes the aggressive phenotype of human inflammatory breast cancer
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Suvendu Das, Rui Qiao, Andrew K. Edwards, Stuart A. Aaronson, Ravi Sachidanandam, Ila Pant, Ruben Fernandez-Rodriguez, Luca Grumolato, Rosa Karlic, Shabnam Jaffer, Aaron Sun, Anita Rogic, Shen Yao, Mihaela Skobe, and Guray Akturk
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Cancer microenvironment ,Skin erythema ,Chemokine ,Receptors, CCR2 ,Science ,Transplantation, Heterologous ,General Physics and Astronomy ,Mice, SCID ,Biology ,CCL2 ,Inflammatory breast cancer ,General Biochemistry, Genetics and Molecular Biology ,Article ,Metastasis ,Transcriptome ,Mice ,Breast cancer ,Cell Line, Tumor ,Tumor-Associated Macrophages ,medicine ,Tumor Microenvironment ,Macrophage ,Animals ,Humans ,Myeloid Cells ,Neoplasm Metastasis ,skin and connective tissue diseases ,Cancer models ,Chemokine CCL2 ,Tumor immunology ,Inflammation ,Gene knockdown ,Multidisciplinary ,General Chemistry ,medicine.disease ,Gene Expression Regulation, Neoplastic ,biology.protein ,Cancer research ,Tumour immunology ,Female ,Inflammatory Breast Neoplasms - Abstract
Inflammatory Breast Cancer (IBC) is a highly aggressive malignancy with distinct clinical and histopathological features whose molecular basis is unresolved. Here we describe a human IBC cell line, A3250, that recapitulates key IBC features in a mouse xenograft model, including skin erythema, diffuse tumor growth, dermal lymphatic invasion, and extensive metastases. A3250 cells express very high levels of the CCL2 chemokine and induce tumors enriched in macrophages. CCL2 knockdown leads to a striking reduction in macrophage densities, tumor proliferation, skin erythema, and metastasis. These results establish IBC-derived CCL2 as a key factor driving macrophage expansion, and indirectly tumor growth, with transcriptomic analysis demonstrating the activation of multiple inflammatory pathways. Finally, primary human IBCs exhibit macrophage infiltration and an enriched macrophage RNA signature. Thus, this human IBC model provides insight into the distinctive biology of IBC, and highlights potential therapeutic approaches to this deadly disease., Inflammatory breast cancer (IBC) is an aggressive form of breast cancer with a poor prognosis. Here the authors report the characterization of a human IBC cell line recapitulating the clinical and histopathological features of the human disease, and implicating its high level of CCL2 in macrophage infiltration and tumor progression.
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- 2021
10. The Evolving Landscape of Antibody-Drug Conjugates for Urothelial Carcinoma
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Abel, Melissa Burkenroad, Aaron Sun, Alexander Lu, Eric and Stefanoudakis, Dimitrios Drakaki, Alexandra
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Overview of Common Antibody Therapeutic Designs (A) the Prototypical Monoclonal Antibody With 2 Identical Variable Components (Fv) That Engage Target Antigens. (B) T-cell-dependent Bispecific Antibodies, With 2 Differing Variable Regions Capable of Targeting Differing Antigens, Resulting in Unique Modes of Action Such as Bringing Target Tumor Cells in Close Proximity With Leukocytes. (C) ADCs Containing Variable Ratios of Cytotoxic Small Molecule Payloads Per Antibody That Act Through an Additional Mechanism Involving the Attached Chemotherapeutic. (D) MMAE, the Small Molecule Payload of Enfortumab/Vedotin, is Depicted Linked to Its Native Antibody via a Covalent Peptide Linker Metastatic urothelial carcinoma (UC) carries a poor prognosis and a 5-year overall survival of less than 5%, despite standard of care therapy using cisplatin-based chemotherapy and immune checkpoint inhibitors. Thus, novel agents that improve survival and have an acceptable toxicity profile are urgently needed. Antibody-drug conjugates (ADCs) represent a promising new treatment option that utilizes the targeting ability of an antibody to deliver cytotoxic drugs directly to tumors. Many ADCs are currently being investigated for treatment of UC, with enfortumab vedotin being recently approved by the US Food and Drug Administration for treatment of metastatic UC with progressive disease after chemotherapy and/or immune checkpoint inhibitors. Overall, ADCs hold promise as a long-awaited treatment option for UC.
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- 2021
11. Exploring Social Dynamics in Online Bookmarking Systems.
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Xiaolong Zheng 0001, Huiqian Li, and Aaron Sun
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- 2008
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12. Socioeconomic inequality, health inequity and well-being of transgender people during the COVID-19 pandemic in Nigeria
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Morenike Oluwatoyin Folayan, Anna Yakusik, Amaka Enemo, Aaron Sunday, Amira Muhammad, Hasiya Yunusa Nyako, Rilwan Mohammed Abdullah, Henry Okiwu, and Erik Lamontagne
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LGBT ,Transgender ,Public health ,Risk-taking ,HIV ,COVID-19 ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background We aimed to explore socioeconomic inequality, health inequity, and the well-being of transgender people during the COVID-19 crisis in Nigeria. Methods Between June and December 2021, a cross-sectional survey was conducted collaboratively with community-based organisations in Nigeria. Participants living with or at risk of HIV were recruited voluntarily, online and face-to-face, using a combination of venue-based and snowball sampling. We assessed the association between gender identity (transgender and vulnerable cisgender women), and (i) socioeconomic inequality measured with socioeconomic status, social status, economic vulnerability, macrosocial vulnerability; (ii) health inequity measured with self-assessment of health, recency of HIV test, access to HIV and sexual and reproductive health services, gender-affirming care, financial and non-financial barriers to accessing health services; and (iii) well-being, measured with gender-based violence, mental health, psychoeconomic preferences. We used multivariable logistic regressions and controlled for interactions and confounders. Results There were 4072 participants; 62% were under 30, and 47% reported living with HIV. One in ten (11.9%; n = 485) was transgender, and 56.5% reported living with HIV. Compared to vulnerable cisgender women, the results showed significantly higher odds (aOR:3.80) of disruption in accessing HIV services in transgender participants; gender-based violence (aOR:2.63); severe (aOR:2.28) symptoms of anxiety and depression. Among the barriers to accessing health and HIV services, transgender had three-time higher odds of reporting additional non-official fees compared to vulnerable cisgender women. The disclosure of their gender identity or sexual orientation was the most important non-financial barrier to accessing health services (aOR:3.16). Transgender participants faced higher housing insecurity (aOR: 1.35) and lower odds of using drugs (aOR:0.48). Importantly, they are more likely to have performed a recent HIV test and less likely to not know their HIV status (aOR:0.38) compared to vulnerable cisgender women. Conclusions Socioeconomic inequality, health and well-being inequity in transgender people appear to be exacerbated by the COVID-19 pandemic in Nigeria. Interventions are necessary to mitigate socioeconomic challenges, address structural inequality, and ensure equitable access to health services to meet the Sustainable Development Goals for transgender people.
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- 2023
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13. Morbid obesity influences the nocturnal electrocardiogram wave and interval durations among suspected sleep apnea patients
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Samu Kainulainen, Aaron Suni, Jukka A. Lipponen, Antti Kulkas, Brett Duce, Henri Korkalainen, Sami Nikkonen, and Saara Sillanmäki
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body mass index ,electrocardiogram ,interval duration ,obesity ,obstructive sleep apnea ,wave duration ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Obesity is a global issue with a major impact on cardiovascular health. This study explores how obesity influences nocturnal cardiac electrophysiology in suspected obstructive sleep apnea (OSA) patients. Methods We randomly selected 12 patients from each of the five World Health Organization body mass index (BMI) classifications groups (ntotal = 60) while keeping the group's age and sex matched. We evaluated 1965 nocturnal electrocardiography (ECG) samples (10 s) using modified lead II recorded during normal saturation conditions. R‐wave peaks were detected and confirmed using dedicated software, with the exclusion of ventricular extrasystoles and artifacts. The duration of waves and intervals was manually marked. The average electric potential graphs were computed for each segment. Thresholds for abnormal ECG waveforms were P‐wave > 120 ms, PQ interval > 200 ms, QRS complex > 120 ms for, and QTc > 440 ms. Results Obesity was significantly (p
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- 2024
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14. The health inequity and socioeconomic inequality faced by adolescent girls and women on the move living with or at high risk of HIV infection, during the COVID-19 pandemic in Nigeria
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Greg Ashefor, Morenike Oluwatoyin Folayan, Matthew Kavanagh, Koubagnine Takpa, Pamela Ogbozor, Veronica Undelikwo, Oluwatoyin Alaba, Erik Lamontagne, Hasiya Yunusa Nyako, Amaka Enemo, Aaron Sunday, Amira Muhammad, Rilwan Mohammed Abdullah, Henry Okiwu, Oluwaranmilowo Amusan, and Gabriel Undelikwo
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Medicine (General) ,R5-920 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Background We assessed if women and girls on the move living with or at high risk of HIV faced increased health inequity and socioeconomic inequalities during the COVID-19 pandemic compared with other vulnerable women and girls.Methods We used data collected through a survey conducted in Nigeria between June and October 2021. Women and girls living with or at risk of HIV were recruited voluntarily, using a combination of venue-based and snowball sampling. We performed multivariable logistic regression models per mobility and HIV status to determine associations between health inequity, socioeconomic inequalities and macrosocial characteristics.Findings There were 3442 participants, of which 700 were on the move. We found no statistical difference between HIV-negative women and girls on the move and those not on the move. On the opposite, we found substantial differences in health inequity and socioeconomic inequalities between women and girls on the move living with HIV and those not on the move living with HIV. There are very strong associations between being a woman or girl on the move living with HIV and facing economic precarity (aOR 6.08, 95% CI 1.94 to 19.03), food insecurity (aOR 5.96, 95% CI 2.16 to 16.50) and experiencing more gender-based violence since COVID-19 started (aOR 5.61, 95% CI 3.01 to 10.47).Interpretation Being a woman or girl on the move and living with HIV compound increased health and socioeconomic vulnerabilities. The COVID-19 crisis seems to have exacerbated inequalities and gender-based violence. These findings call for more feminist interventions to protect women on the move living with HIV during health crises.
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- 2023
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15. Interorganizational Projects: Reexamining Innovation Implementation via IPD Cases
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Weida Aaron Sun, Vernon D. Miller, Sinem Mollaoglu, and Jihyun Esther Paik
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Process management ,Management science ,Strategy and Management ,05 social sciences ,0211 other engineering and technologies ,General Engineering ,02 engineering and technology ,Building and Construction ,Management Science and Operations Research ,021105 building & construction ,0502 economics and business ,Industrial relations ,Innovation implementation ,Business ,050203 business & management - Published
- 2017
16. Incorporating conditional random fields and active learning to improve sentiment identification
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Alok Choudhary, Yusheng Xie, Yi Yang, Aaron Sun, Kunpeng Zhang, and Hengchang Liu
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Conditional random field ,Structure (mathematical logic) ,Training set ,Computer science ,business.industry ,Active learning (machine learning) ,Cognitive Neuroscience ,Sentiment analysis ,Supervised learning ,Linguistics ,Context (language use) ,Problem-Based Learning ,Machine learning ,computer.software_genre ,Identification (information) ,Pattern Recognition, Visual ,Artificial Intelligence ,Active learning ,Humans ,Artificial intelligence ,business ,computer ,Natural language processing ,Sentence - Abstract
Many machine learning, statistical, and computational linguistic methods have been developed to identify sentiment of sentences in documents, yielding promising results. However, most of state-of-the-art methods focus on individual sentences and ignore the impact of context on the meaning of a sentence. In this paper, we propose a method based on conditional random fields to incorporate sentence structure and context information in addition to syntactic information for improving sentiment identification. We also investigate how human interaction affects the accuracy of sentiment labeling using limited training data. We propose and evaluate two different active learning strategies for labeling sentiment data. Our experiments with the proposed approach demonstrate a 5%-15% improvement in accuracy on Amazon customer reviews compared to existing supervised learning and rule-based methods.
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- 2014
17. Interorganizational Projects: Reexamining Innovation Implementation via IPD Cases
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Esther Paik, Jihyun, primary, Miller, Vernon, additional, Mollaoglu, Sinem, additional, and Aaron Sun, Weida, additional
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- 2017
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18. QTc prolongation is associated with severe desaturations in stroke patients with sleep apnea
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Saara Sillanmäki, Jukka A. Lipponen, Henri Korkalainen, Antti Kulkas, Timo Leppänen, Sami Nikkonen, Juha Töyräs, Brett Duce, Aaron Suni, and Samu Kainulainen
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QTc ,Stroke ,Obstructive sleep apnea ,Desaturation ,Repolarisation ,Diseases of the respiratory system ,RC705-779 - Abstract
Abstract Background Obstructive sleep apnea (OSA) is associated with vascular diseases from which stroke and sudden cardiac death are the most significant ones. It is known that disturbances of the autonomic nervous system and electrocardiographic changes are seen in patients with a previous cerebrovascular event. However, the pathophysiological cascade between breathing cessations, autonomic regulation, and cardiovascular events is not fully understood. Methods We aimed to investigate the acute effect of desaturation on repolarisation in OSA patients with a previous stroke. We retrospectively analysed heart-rate corrected QT (QTc) intervals before, within, and after 975 desaturations in OSA patients with a stroke history and at least moderate sleep apnea (apnea–hypopnea index ≥ 15 events/h, n = 18). For the control population (n = 18), QTc intervals related to 1070 desaturation were analysed. Desaturations were assigned to groups according to their length and duration. Groupwise comparisons and regression analyses were further executed to investigate the influence of desaturation features on repolarization. Results In the stroke population the QTc prolonged at least 11 ms during 27.1% of desaturations, and over 20 ms during 12.2% of desaturations. QTc was significantly prolonged during longer (> 30 s, p 7%, p 45 s desaturations and 7.4 ms during > 9% deep desaturations. In the control population, QTc prolongation was observed but to a significantly lesser extent than in stroke patients. In addition, desaturation duration was found to be an independent predictor of QTc prolongation (β = 0.08, p 30 s) and deeper (> 7%) desaturations prolong QTc in patients with stroke history. A significant proportion of desaturations produced clinically relevant QTc prolongation. As it is known that a long QTc interval is associated with lethal arrhythmias, this finding might in part explain the pathophysiological sequelae of cardiovascular mortality in OSA patients with a history of stroke.
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- 2022
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19. A Systematic Framework for Sentiment Identification by Modeling User Social Effects
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Hengchang Liu, Aaron Sun, Kunpeng Zhang, and Yi Yang
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World Wide Web ,Identification (information) ,Focus (computing) ,Social computing ,User profile ,Social media optimization ,Political science ,Collaborative filtering ,Social media ,Preference - Abstract
Social media is becoming a major and popular technological platform that allows users to express personal opinions toward the subjects with shared interests. Identifying the sentiments of these social media data can help users make informed decisions. Existing research mainly focus on developing algorithms by mining textual information in social media. However, none of them collectively consider the relationships among heterogeneous social entities. Since users interact with social brands in social platforms, their opinions on specific topics are inevitably dependent on many social effects such as user preference on topics, peer influence, user profile information, etc. In this paper, we present a systematic framework to identify sentiments by incorporating user social effects besides textual information. We apply distributed item-based collaborative filtering technique to estimate user preference. Our experiments, conducted on large datasets from current major social platforms, such as Facebook, Twitter, Amazon.com, and Flyertalk.com, demonstrate that incorporating those user social effects can significantly improve sentiment identification accuracy.
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- 2014
20. An information diffusion-based recommendation framework for micro-blogging
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Daniel Dajun Zeng, Daning Hu, Jiesi Cheng, Aaron Sun, and University of Zurich
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Computer science ,Microblogging ,10009 Department of Informatics ,Benchmark (computing) ,Volume (computing) ,Social media ,Recommender system ,Diffusion (business) ,000 Computer science, knowledge & systems ,Data science ,Computer Science Applications ,Information Systems - Abstract
Micro-blogging is increasingly evolving from a daily chatting tool into a critical platform for individuals and organizations to seek and share real-time news updates during emergencies. However, seeking and extracting useful information from micro-blogging sites poses significant challenges due to the volume of the traffic and the presence of a large body of irrelevant personal messages and spam. In this paper, we propose a novel recommendation framework to overcome this problem. By analyzing information diffusion patterns among a large set of micro-blogs that play the role of emergency news providers, our approach selects a small subset as recommended emergency news feeds for regular users. We evaluate our diffusion-based recommendation framework on Twitter during the early outbreak of H1N1 Flu. The evaluation results show that our method results in more balanced and comprehensive recommendations compared to benchmark approaches.
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- 2011
21. Maximizing Influence Through Information-Overloaded Online Social Networks
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Daniel Zeng, Aaron Sun, and Jiesi Cheng
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Viral marketing ,Social network ,Computer science ,business.industry ,Maximization ,Marketing ,Set (psychology) ,Centrality ,Heuristics ,business ,Data science ,Information overload ,Messaging pattern - Abstract
Online social communities have become an important communication channel for people to share and discover information. Pieces of information spread within the community via the underlying social network, from one individual to another. However, with the unprecedented ease and low cost of communication provided by online systems, information overload emerges as a negative factor that potentially threatens the effectiveness of communication. As such, traditional single-message based diffusion models, such as Independent Cascade Model (ICM), are inadequate for describing the role of information overload. We then proposed an extended version of ICM (EICM) that explicitly takes the message multiplicity into account, after examining the message exchange patterns observed from a real online social community. We extensively evaluated this new diffusion model and compared with standard ICM in addressing one fundamental algorithmic problem related to viral marketing: How to select a set of network nodes/individuals to facilitate information diffusion and maximize influence? The evaluation results obtained from using both real and simulated data sets show that our approach results in node-selection heuristics outperforming well-studied notions of various centrality measures based on the ICM. The study and findings presented in this research have important managerial implications. In particular, from a viral marketing perspective, information overload effect should be recognized in order for campaign managers to build advantages in their influence maximization decisions.
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- 2010
22. An Information Diffusion Based Recommendation Framework for Micro-Blogging
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Daning Hu, Jiesi Cheng, Daniel Dajun Zeng, and Aaron Sun
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World Wide Web ,Computer science ,Microblogging ,Benchmark (computing) ,Social media ,Recommender system - Abstract
Micro-blogging is increasingly extending its role from a daily chatting tool into a critical platform for individuals and organizations to seek and share real-time news updates during emergencies. However, seeking and extracting useful information from micro-blogging sites poses significant challenges due to the volume of the traffic and the presence of a large body of irrelevant personal messages and spams. In this paper, we propose a novel recommendation framework to overcome this problem. By analyzing information diffusion patterns among a large set of micro-blogs who play the role of emergency news providers, our approach could select a small subset as recommended emergency news feeds for regular users. We have evaluated our diffusion-based recommendation framework on Twitter during the early outbreak of H1N1 Flu. The evaluation results show that our method results in more balanced and comprehensive recommendations compared to benchmark approaches.
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- 2010
23. Exploring Social Dynamics in Online Bookmarking Systems
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Aaron Sun, Xiaolong Zheng, and Huiqian Li
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World Wide Web ,Social dynamics ,Focus (computing) ,Social media optimization ,Bookmarking ,Computer science ,Information sharing ,Social relation - Abstract
Web 2.0 technologies have spawned different types of information sharing systems, including online bookmarking systems. These information sharing systems have facilitated collaboration among their users with similar interests. They also provide a powerful means of sharing, organizing, and finding contents and contacts [1]. In this paper we focus on evaluating social interaction among users on Del.icio.us, which is one of the most popular and paradigmatic online bookmarking systems.
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- 2008
24. Network-Based Analysis of Beijing SARS Data
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Yuan Luo, Xiaolong Zheng, Quanyi Wang, Fei-Yue Wang, Aaron Sun, and Daniel Zeng
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Geography ,Operations research ,Beijing ,fungi ,Control (management) ,Patient contact ,Outbreak control ,Complex network analysis - Abstract
In this paper, we analyze Beijing SARS data using methods developed from the complex network analysis literature. Three kinds of SARS-related networks were constructed and analyzed, including the patient contact network, the weighted location (district) network, and the weighted occupation network. We demonstrate that a network-based data analysis framework can help evaluate various control strategies. For instance, in the case of SARS, a general randomized immunization control strategy may not be effective. Instead, a strategy that focuses on nodes (e.g., patients, locations, or occupations) with high degree and strength may lead to more effective outbreak control and management.
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- 2008
25. Discovering Trends in Collaborative Tagging Systems
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Daniel Zeng, Aaron Sun, Xiaolong Zheng, and Huiqian Li
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Application Context ,Social computing ,Computer science ,Classification scheme ,Tracking (education) ,Data science ,Preliminary analysis - Abstract
Collaborative tagging systems (CTS) offer an interesting social computing application context for topic detection and tracking research. In this paper, we apply a statistical approach for discovering topic-specific bursts from a popular CTS - del.icio.us. This approach allows trend discovery from different components of the system such as users, tags, and resources. Based on the detected topic bursts, we perform a preliminary analysis of related burst formation patterns. Our findings indicate that users and resources contributing to the bursts can be classified into two categories: old and new, based on their past usage histories. This classification scheme leads to interesting empirical findings.
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- 2008
26. Diagnostic Performance of Fractional Flow Reserve From CT Coronary Angiography With Analytical Method
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Jun-Mei Zhang, Huan Han, Ru-San Tan, Ping Chai, Jiang Ming Fam, Lynette Teo, Chee Yang Chin, Ching Ching Ong, Ris Low, Gaurav Chandola, Shuang Leng, Weimin Huang, John C. Allen, Lohendran Baskaran, Ghassan S. Kassab, Adrian Fatt Hoe Low, Mark Yan-Yee Chan, Koo Hui Chan, Poay Huan Loh, Aaron Sung Lung Wong, Swee Yaw Tan, Terrance Chua, Soo Teik Lim, and Liang Zhong
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coronary artery disease ,fractional flow reserve ,computed tomography coronary angiography ,analytical method ,non-invasive ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
The aim of this study was to evaluate a new analytical method for calculating non-invasive fractional flow reserve (FFRAM) to diagnose ischemic coronary lesions. Patients with suspected or known coronary artery disease (CAD) who underwent computed tomography coronary angiography (CTCA) and invasive coronary angiography (ICA) with FFR measurements from two sites were prospectively recruited. Obstructive CAD was defined as diameter stenosis (DS) ≥50% on CTCA or ICA. FFRAM was derived from CTCA images and anatomical features using analytical method and was compared with computational fluid dynamics (CFD)-based FFR (FFRB) and invasive ICA-based FFR. FFRAM, FFRB, and invasive FFR ≤ 0.80 defined ischemia. A total of 108 participants (mean age 60, range: 30–83 years, 75% men) with 169 stenosed coronary arteries were analyzed. The per-vessel accuracy, sensitivity, specificity, and positive predictive and negative predictive values were, respectively, 81, 75, 86, 81, and 82% for FFRAM and 87, 88, 86, 83, and 90% for FFRB. The area under the receiver operating characteristics curve for FFRAM (0.89 and 0.87) and FFRB (0.90 and 0.86) were higher than both CTCA- and ICA-derived DS (all p < 0.0001) on per-vessel and per-patient bases for discriminating ischemic lesions. The computational time for FFRAM was much shorter than FFRB (2.2 ± 0.9 min vs. 48 ± 36 min, excluding image acquisition and segmentation). FFRAM calculated from a novel and expeditious non-CFD approach possesses a comparable diagnostic performance to CFD-derived FFRB, with a significantly shorter computational time.
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- 2021
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27. Burst Detection From Multiple Data Streams: A Network-Based Approach.
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Aaron Sun, Daniel Dajun Zeng, and Hsinchun Chen
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MARKOV processes , *PROBABILISTIC number theory , *ELECTRONIC data processing , *BINARY large objects , *DATA , *DEMODULATION - Abstract
The article presents the novel method to analyze and identify correlated burst patterns through multiple data streams that coevolve overtime. It discusses the use of dynamic probabilistic network to model the dependency structures observed in the data streams. In this regard, it elaborates that the dependencies provides meaningful information concerning the overall system dynamics, which integrated into the burst detection process.
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- 2010
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28. Modulation of digestive physiology and biochemistry in Mytilus californianus in response to feeding level acclimation and microhabitat
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Kwasi M. Connor, Aaron Sung, Nathan S. Garcia, Andrew Y. Gracey, and Donovan P. German
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Clearance rate ,Digestive enzyme activity ,Growth ,Rate-maximization ,Respiration rate ,Thermal stress ,Yield-maximization ,Science ,Biology (General) ,QH301-705.5 - Abstract
The intertidal mussel Mytilus californianus is a critical foundation species that is exposed to fluctuations in the environment along tidal- and wave-exposure gradients. We investigated feeding and digestion in mussels under laboratory conditions and across environmental gradients in the field. We assessed whether mussels adopt a rate-maximization (higher ingestion and lower assimilation) or a yield-maximization acquisition (lower ingestion and higher assimilation) strategy under laboratory conditions by measuring feeding physiology and digestive enzyme activities. We used digestive enzyme activity to define resource acquisition strategies in laboratory studies, then measured digestive enzyme activities in three microhabitats at the extreme ends of the tidal- and wave-exposure gradients within a stretch of shore (
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- 2016
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29. Simplified Models of Non-Invasive Fractional Flow Reserve Based on CT Images.
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Jun-Mei Zhang, Liang Zhong, Tong Luo, Aileen Mae Lomarda, Yunlong Huo, Jonathan Yap, Soo Teik Lim, Ru San Tan, Aaron Sung Lung Wong, Jack Wei Chieh Tan, Khung Keong Yeo, Jiang Ming Fam, Felix Yung Jih Keng, Min Wan, Boyang Su, Xiaodan Zhao, John Carson Allen, Ghassan S Kassab, Terrance Siang Jin Chua, and Swee Yaw Tan
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Medicine ,Science - Abstract
Invasive fractional flow reserve (FFR) is the gold standard to assess the functional coronary stenosis. The non-invasive assessment of diameter stenosis (DS) using coronary computed tomography angiography (CTA) has high false positive rate in contrast to FFR. Combining CTA with computational fluid dynamics (CFD), recent studies have shown promising predictions of FFRCT for superior assessment of lesion severity over CTA alone. The CFD models tend to be computationally expensive, however, and require several hours for completing analysis. Here, we introduce simplified models to predict noninvasive FFR at substantially less computational time. In this retrospective pilot study, 21 patients received coronary CTA. Subsequently a total of 32 vessels underwent invasive FFR measurement. For each vessel, FFR based on steady-state and analytical models (FFRSS and FFRAM, respectively) were calculated non-invasively based on CTA and compared with FFR. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value were 90.6% (87.5%), 80.0% (80.0%), 95.5% (90.9%), 88.9% (80.0%) and 91.3% (90.9%) respectively for FFRSS (and FFRAM) on a per-vessel basis, and were 75.0%, 50.0%, 86.4%, 62.5% and 79.2% respectively for DS. The area under the receiver operating characteristic curve (AUC) was 0.963, 0.954 and 0.741 for FFRSS, FFRAM and DS respectively, on a per-patient level. The results suggest that the CTA-derived FFRSS performed well in contrast to invasive FFR and they had better diagnostic performance than DS from CTA in the identification of functionally significant lesions. In contrast to FFRCT, FFRSS requires much less computational time.
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- 2016
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30. Using information communication technologies to increase the institutional capacity of local health organisations in Africa: a case study of the Kenya Civil Society Portal for Health
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Charles Juma, Aaron Sundsmo, Boniface Maket, Richard Powell, and Gilbert Aluoch
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africa ,capacity building ,data for decision making ,ict for development ,developing countries ,kenya ,knowledge management ,Medicine - Abstract
INTRODUCTION: achieving the healthcare components of the United Nations' Millennium Development Goals is significantly premised on effective service delivery by civil society organisations (CSOs).However, many CSOs across Africalack the necessary capacity to perform this role robustly. This paper reports on an evaluation of the use, and perceived impact, of aknowledge management tool upon institutional strengthening among CSOs working in Kenya's health sector. METHODS: three methods were used: analytics data; user satisfaction surveys; and a furtherkey informant survey. RESULTS: satisfaction with the portal was consistently high, with 99% finding the quality and relevance of the content very good or good for institutional strengthening standards, governance, and planning and resource mobilisation. Critical facilitators to the success of knowledge management for CSO institutional strengthening were identified as people/culture (developed resources and organisational narratives) and technology (easily accessible, enabling information exchange, tools/resources available, access to consultants/partners).Critical barriers were identified as people/culture (database limitations, materials limitations, and lack of active users), and process (limited access, limited interactions, and limited approval process). CONCLUSION: this pilot study demonstrated the perceived utility of a web-based knowledge management portal among developing nations' CSOs, with widespread satisfaction across multiple domains, which increased over time. Providing increased opportunities for collective mutual learning, promoting a culture of data use for decision making, and encouraging all health organisations to be learning institutions should be a priority for those interested in promoting sustainable long-term solutions for Africa.
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- 2015
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31. The Appropriate Use of Percutaneous Coronary Intervention in Contemporary Clinical Practice
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Chee Tang Chin MBChB, MRCP and Aaron Sung Lung Wong MBBS, MRCP
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Medicine - Abstract
Percutaneous coronary intervention (PCI) is common and generally low risk. Although shown to be of significant benefit in certain clinical situations, especially in the context of acute coronary syndromes, there exist clinical scenarios where PCI has not been shown to be helpful. In these cases, the risk of periprocedural complications as well as longer term issues such as bleeding or stent thrombosis mean that PCI may potentially be harmful. To inform best clinical practice, we now have published recommendations with regards to the Appropriate Use Criteria (AUC) for coronary revascularisation. The goal of the AUC is to guide physician decision-making and future research as well as to label coronary revascularisation more clearly for patients and payors in regards to its expected benefits in certain situations. In this review, we summarise and discuss the more clinically relevant of these AUC, either because they are contentious or of particular relevance to the local context or practice. We conclude that there continue to be situations whereby inappropriate PCIs are performed, and these represent opportunities for quality improvement.
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- 2015
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32. Review of the Clinical Evidence and Controversies in Therapeutic Hypothermia for Survivors of Sudden Cardiac Death
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Eric Tien Siang Lim MBBChir, MRCP, Aaron Sung Lung Wong MBBChir, Nur Shahidah binte Ahmad BA, Kenneth Boon Kiat Tan MBBS, MCEM, Marcus Eng Hock Ong MBBS, MPH, and Jack Wei Chieh Tan MBBS, MRCP
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Medicine - Abstract
Sudden cardiac arrest constitutes a major public health burden in both developed and developing countries. In those successfully resuscitated from cardiac arrest, subsequent mortality is still high (∼75%) and is due to a combination of ischaemia and reperfusion injury. The purpose of this review is to describe the experimental and clinical evidence supporting therapeutic hypothermia in survivors of sudden cardiac arrest. We also discuss controversies and unresolved issues in therapeutic hypothermia, including the optimum target temperature for therapeutic hypothermia, and the role of pre-hospital induction of hypothermia. We conclude with a perspective on therapeutic hypothermia as it applies to the Singapore context.
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- 2015
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33. Organizational HIV monitoring and evaluation capacity rapid needs assessment: the case of Kenya
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Mwende Mbondo, Jennifer Scherer, Gilbert Onyango Aluoch, Aaron Sundsmo, and Njeri Mwaura
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hiv/aids ,monitoring and evaluation ,strategic information ,rapid needs assessment ,kenya ,mand e capacity building ,kenya national hiv/aids strategic plan (knasp) ,centers for disease control and prevention ,Medicine - Abstract
INTRODUCTION: Due to the commitment by the Government of Kenya (GoK) and international donors to address HIV/AIDS, Kenya has some of Africas most developed health infrastructure for tackling the crisis. Despite this commitment, significant gaps exist in the national HIV/AIDS monitoring and evaluation (Mand E) system. To identify these gaps and opportunities for improvement, the U.S. Centers for Disease Control and Prevention funded the Strengthening HIV Strategic Information in Kenya project, which conducted an organizational HIV M"and E{" capacity rapid needs assessment (RNA). METHODS: The project included an in-depth desk review of national documents, policies, tools, and international best practices. National, regional, and district officials from government agencies, development partners, and implementing partners participated in key informant interviews and focus group discussions. Given the large number of regions and districts, purposive sampling was used to select 16 facilities in 8 districts across 2 regions based on the general quality of the reported HIV data and the number of partners supporting the regions. RESULTS: RNA findings revealed tremendous improvements at the national level and in the various subsystems that contribute to the overall HIV strategic information. There also were significant gaps, including in a lack of M and E guidelines, parallel reporting systems, feedback given to subnational levels, and data use and general data management and use capacity at subnational levels. CONCLUSION: An urgent need exists for the development of national "M and E" guidelines and a comprehensive training curriculum. To ensure success further, capacity building for subnational levels should be conducted and feedback channels to subnational staff should be established and maintained.
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- 2013
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34. A Multi-Level Task Framework for Event Sequence Analysis.
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Zinat KT, Sakhamuri SN, Chen AS, and Liu Z
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Despite the development of numerous visual analytics tools for event sequence data across various domains, including but not limited to healthcare, digital marketing, and user behavior analysis, comparing these domain-specific investigations and transferring the results to new datasets and problem areas remain challenging. Task abstractions can help us go beyond domain-specific details, but existing visualization task abstractions are insufficient for event sequence visual analytics because they primarily focus on multivariate datasets and often overlook automated analytical techniques. To address this gap, we propose a domain-agnostic multi-level task framework for event sequence analytics, derived from an analysis of 58 papers that present event sequence visualization systems. Our framework consists of four levels: objective, intent, strategy, and technique. Overall objectives identify the main goals of analysis. Intents comprises five high-level approaches adopted at each analysis step: augment data, simplify data, configure data, configure visualization, and manage provenance. Each intent is accomplished through a number of strategies, for instance, data simplification can be achieved through aggregation, summarization, or segmentation. Finally, each strategy can be implemented by a set of techniques depending on the input and output components. We further show that each technique can be expressed through a quartet of action-input-output-criteria. We demonstrate the framework's descriptive power through case studies and discuss its similarities and differences with previous event sequence task taxonomies.
- Published
- 2024
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