hamed alavi - Academia.edu (original) (raw)

Papers by hamed alavi

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The high concentration of air pollutants in indoor environments can have a remarkable adverse imp... more The high concentration of air pollutants in indoor environments can have a remarkable adverse impact on health and well-being, cognitive performance and productivity. Indoor air pollutants are especially problematic in naturally ventilated shared spaces such as classrooms and meeting rooms, where human-generated pollutants can rise rapidly. When the inhabitants are exposed to indoor air pollution, recovering from its ramifications takes time and harms their well-being in the long run. In our approach, we seek to predict and prevent such hazardous situations instead of rectifying them after they happen. The prediction and prevention are accomplished through algorithms that can learn from the evolution of air pollutants and other variables to indicate whether or not a high level of pollution is forecast. We present two AI-enabled methods, one providing the forecast for the concentration level of carbon dioxide in the next 5 and 20 minutes with 86% and 92% accuracy. The second algorith...

Adjunct Proceedings of the 2021 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2021 ACM International Symposium on Wearable Computers, 2021

Unlike traditional workshops, SensiBlend is a living experiment about the future of remote, hybri... more Unlike traditional workshops, SensiBlend is a living experiment about the future of remote, hybrid, and blended experiences within professional and other social contexts. The interplay of interpersonal relationships with tools and spaces-digital and physical-has been abruptly challenged and fundamentally altered as a result of the COVID-19 pandemic. With this meta-workshop, we seek to scrutinize and advance the role and impact of Ubiquitous Computing in the new "blended" social reality, and raise questions relating to the specific attributes of socio-technical experiences in the future organization of interpersonal relationships. How do we better equip people to deal with blended experiences? What dimensions of socio-technical experiences are at stake? To this end, we will utilize the occasion of a virtual UbiComp in combination with novel remote-working tools and participatory sensing with attendees to collectively examine, discuss, and elicit the potential routes of augmenting social practices in a discourse about the future of blended working, socializing, and living. CCS CONCEPTS • Human-centered computing → Ubiquitous and mobile computing.

Human-Computer Interaction – INTERACT 2017, 2017

Comfort as a technical term in the domain of architecture has been used meticulously to describe,... more Comfort as a technical term in the domain of architecture has been used meticulously to describe, assess, and understand some of the essential qualities of buildings, across four dimensions: visual, thermal, acoustic, and respiratory. This body of knowledge can be drawn upon to shed light on the growing branch of HCI that pursues a shift from "artifact" to "environment" (and from "usability" to "comfort"). We contribute to this conceptual-contextual transition in three consecutive steps: 1) sketch the outline of comfort studies in the scholar field of Architecture and the ones in Human-Computer Interaction, 2) propose a schematic model of comfort that captures its interactive characteristics and, 3) demonstrate an interactive tool, called ComfortBox, that we prototyped to help answer some of the research questions about the perception of comfort in built environments.

ACM Transactions on Computer-Human Interaction, 2020

Since the introduction of the iconic Aware Home project [39] in 1999, the notion of “living labor... more Since the introduction of the iconic Aware Home project [39] in 1999, the notion of “living laboratory” has been taken up and developed in HCI research. Many of the underpinning assumptions have evolved over the past two decades in various directions, while the same nomenclature is employed—inevitably in ambiguous ways. This contribution seeks to elicit an organized understanding of what we talk about and when we talk about living lab studies in HCI. This is accomplished through the methods of discourse analysis [66, 69], a combination of coding, hypothesis generation, and inferential statistics on the coded data. Analysing the discursive context within which the term living laboratory (or lab) appears in 152 SIGCHI and TOCHI articles, we extracted five divergent strands with overlapping but distinct conceptual frameworks, labeled as “Visited Places,” “Instrumented Places,” “Instrumented People,” “Lived-in Places,” and “Innovation Spaces.” In the first part of this article, we descr...

The Annals of Thoracic Surgery, 2015

Purpose. This study describes the efforts to develop and test the first hybrid tissueengineered h... more Purpose. This study describes the efforts to develop and test the first hybrid tissueengineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform tissue layers composed of multiple cell types. Description. The trileaflet Nitinol mesh scaffolds underwent three-dimensional cell culture with smooth muscle and fibroblast/myofibroblast cells enclosing the mesh, which were finally covered by an endothelial cell layer. Evaluation. Quantitative and qualitative assays were performed to analyze the microstructure of the tissues. A tissue composition almost similar to that of natural heart valve leaflets was observed. The function of the valves and their Nitinol scaffolds were tested in a heart flow simulator that confirmed the trileaflet valves open and close robustly under physiologic flow conditions with an effective orifice area of 75%. The tissue-metal attachment of the leaflets once exposed to physiologic flow rates was tested and approved. Conclusions. Our preliminary results indicate that the novel hybrid approach with nondegradable scaffold for engineering heart valves is viable and may address the issues associated with current tissue-engineered valves developed with degradable scaffolds.

American Journal of Physiology-Heart and Circulatory Physiology, 2015

The extracellular matrix of the atrioventricular (AV) valves' leaflets has a key role in the ... more The extracellular matrix of the atrioventricular (AV) valves' leaflets has a key role in the ability of these valves to properly remodel in response to constantly varying physiological loads. While the loading on mitral and tricuspid valves is significantly different, no information is available on how collagen fibers change their orientation in response to these loads. This study delineates the effect of physiological loading on AV valves' leaflets microstructures using Second Harmonic Generation (SHG) microscopy. Fresh natural porcine tricuspid and mitral valves' leaflets ( n = 12/valve type) were cut and prepared for the experiments. Histology and immunohistochemistry were performed to compare the microstructural differences between the valves. The specimens were imaged live during the relaxed, loading, and unloading phases using SHG microscopy. The images were analyzed with Fourier decomposition to mathematically seek changes in collagen fiber orientation. Despite th...

Annals of biomedical engineering, Jan 7, 2014

In this portion of an extensive review of heart valve engineering, we focus on the current and em... more In this portion of an extensive review of heart valve engineering, we focus on the current and emerging technologies and techniques to repair or replace the mitral valve. We begin with a discussion of the currently available mechanical and bioprosthetic mitral valves followed by the rationale and limitations of current surgical mitral annuloplasty methods; a discussion of the technique of neo-chordae fabrication and implantation; a review the procedures and clinical results for catheter-based mitral leaflet repair; a highlight of the motivation for and limitations of catheter-based annular reduction therapies; and introduce the early generation devices for catheter-based mitral valve replacement.

The Annals of Thoracic Surgery, 2014

Annals of Biomedical Engineering, 2012

When implanted inside the body, bioprosthetic heart valve leaflets experience a variety of cyclic... more When implanted inside the body, bioprosthetic heart valve leaflets experience a variety of cyclic mechanical stresses such as shear stress due to blood flow when the valve is open, flexural stress due to cyclic opening and closure of the valve, and tensile stress when the valve is closed. These types of stress lead to a variety of failure modes. In either a natural valve leaflet or a processed pericardial tissue leaflet, collagen fibers reinforce the tissue and provide structural integrity such that the very thin leaflet can stand enormous loads related to cyclic pressure changes. The mechanical response of the leaflet tissue greatly depends on collagen fiber concentration, characteristics, and orientation. Thus, understating the microstructure of pericardial tissue and its response to dynamic loading is crucial for the development of more durable heart valve, and computational models to predict heart valves' behavior. In this work, we have characterized the 3D collagen fiber arrangement of bovine pericardial tissue leaflets in response to a variety of different loading conditions under Second-Harmonic Generation Microscopy. This real-time visualization method assists in better understanding of the effect of cyclic load on collagen fiber orientation in time and space.

Tissue Engineering Part C: Methods, 2012

Engineering of the membrane-like tissue structures to be utilized in highly dynamic loading envir... more Engineering of the membrane-like tissue structures to be utilized in highly dynamic loading environments such as the cardiovascular system has been a challenge in the past decade. Scaffolds are critical components of the engineered tissue membranes and allow them being formed in vitro and remain secure in vivo when implanted in the body. Several approaches have been taken to develop scaffolds for tissue membranes. However, all methods entail limitations due to structural vulnerability, short-term functionality, and mechanical properties of the resulted membrane constructs. To overcome these issues, we have developed a novel hybrid scaffold made of an extra thin layer of metal mesh tightly enclosed by biological matrix components. This approach retains all the advantages of using biological scaffolds while developing a strong extracellular matrix that can stand various types of loads after implantation inside the body.

Management Systems in Production Engineering

Transferring inventions of academic scientists to private enterprises for the purpose of commerci... more Transferring inventions of academic scientists to private enterprises for the purpose of commercialization is long known as University-Industry (firm) Technology Transfer While the importance of this phenomenon is simultaneously raising in public and private sector, only a part of patented academic inventions succeed in passing the process of commercialization. Despite the fact that formal Technology Transfer process and licencing of patented innovations to third party is the main legal tool for safeguarding rights of academic inventors in commercialization of their inventions, it is not sufficient for transmitting tacit knowledge which is necessary in exploitation of transferred technology. Existence of reciprocal and complementary relations between formal and informal technology transfer process has resulted in formation of different models for university-industry organizational collaboration or even integration where licensee firms keep contact with academic inventors after gaini...

Despite substantial research in the past few decades, only slight progress has been made toward d... more Despite substantial research in the past few decades, only slight progress has been made toward developing biocompatible, tissue-engineered scaffolds for heart valve leaflets that can withstand the dynamic pressure inside the heart. Recent progress on the development of hybrid scaffolds, which are composed of a thin metal mesh enclosed by multi-layered tissue, appear to be promising for heart valve engineering. This approach retains all the advantages of biological scaffolds while developing a strong extracellular matrix backbone to withstand dynamic loading. This study aims to test the inflammatory response of hybrid tissueengineered leaflets based on characterizing the activation of macrophage cells cultured on the surfaces of the tissue construct. The results indicate that integration of biological layers around a metal mesh core-regardless of its typemay reduce the evoked inflammatory responses by THP-1 monocyte-like cells. This observation implies that masking a metal implant within a tissue construct prior to implantation can hide it from the immune system and may improve the implant's biocompatibility.