The advent of metamaterials—hierarchical structures that manifest properties beyond those found in nature through geometry rather than material composition—inspired new possibilities and research in many fields. In mechanics, periodic metamaterials exhibit behaviors ranging from unprecedented compressibility to extreme stiffness. Numerous geometric classes of metamaterials with these properties have been discovered,...
Wearable visual systems, such as ego-centric wearable cameras, have failed to integrate into everyday life. We have witnessed the abandonment of wearable visual systems as consumer devices (e.g., Google Glass) and as research tools (e.g., SenseCam). While it is natural for some technologies to die out, visual wearable systems are...
In this dissertation, we aim to develop algorithms that achieve optimality with provable complexity guarantees under various settings in reinforcement learning (RL). Specifically, in Markov decision processes (MDPs), we study single-agent and multi-agent online RL, respectively, and offline RL under the presence of unobserved confounders. Single-agent online RL. We design...
In recent years, machine learning on graphs (or networks) has gone from a niche topic with only a few active researchers worldwide, to a heavily invested field with novel use cases for dealing with relationships and/or interactions within complex systems in the natural and social sciences. Traditionally, choosing the right...
X-ray imaging at nano and micro-scale is of great importance for the material science and defense industry. Large penetration depth and low wavelength of x-rays offer an important potential to image objects at high resolution and in a non-invasive process. While the ever-growing community is pursuing novel applications and looking...
Visual Question Answering (VQA) increasingly attracts industry and academia attention. It requires the model to provide a natural language answer by an image and a related natural language question. Meanwhile, it relates to multidisciplinary research such as natural language understanding, visual information retrieval, and multimodal reasoning. As a multimodality task,...
Imagine sitting in a room listening to some friends play a song. Perhaps one friend is playing guitar, another playing bass, and a third is playing drums. The musical content in this scene is extraordinarily complex, yet it contains many types of structure that is easy for us to comprehend....
Wearable-based human activity recognition is well-studied in the machine learning and pervasive computing community. A large corpus of studies focused on using wearable sensors to recognize health-related behaviors that involve high periodicity in the sensed signal, such as sitting, walking, and running. Other activities that occur less frequently throughout the...
Asymmetric relationships between creators and consumers in peer-produced knowledge repositories produce inequitable knowledge representation--or knowledge gaps. These gaps result in unequal access to information, and downstream technologies that leverage peer-produced data perpetuate these inequities. Effective knowledge gap identification represents a necessary first step towards equitable knowledge representation. However, while prior...
The past decade has seen the rapid progress of deep learning, which becomes a game-changing technique in different data-intensive domains, with the availability of large scale data, cost-effective computing hardware and more advanced learning theory and algorithms. Despite of the rapid progress of deep learning methods in daily-life applications, such...
Automated driving has become a very popular topic in the recent years and is becoming more and more of a reality. In this new trend, High Definition (HD) maps play an important role in many ways that will provide a safer and more efficient driving experience, especially in terms of...
Modern data sets are increasingly vast, not only in the number of samples, but also in the number of measurements, or features, that they contain. This high-dimensionality poses a unique set of problems for data analysis due to a set of phenomena known as ``the curse of dimensionality.'' This thesis...
Art has been tied to scientific and technological advancements throughout history, providing methods and mediums for communication, expression, and exploration. Art is a dialogic domain that evolves with the technological advances in society–incorporating technology and computational tools to create new genres of art. We live in an increasingly computational and...
Since the invitation of ARPANet in 1969, network protocols and communication systems have continued to emerge. Especially in the past decade, the prosperity of mobile internet and cloud computing has resulted in a large number of network protocols and communication systems, which have become critical infrastructure for our society. Availability...
The rise and racial gap in maternal mortality and morbidity in the US growing public health crisis. The US maternal mortality rate is double that of peer countries such as the UK and Canada. Even more striking, Black women are 243% more likely to die from childbirth-related causes. According to...
We consider general utility models and information structures of the agents and illustrate when economic conclusions for designing simple mechanisms in classical settings extends for general environments. We show that whether economic conclusions can be generalized depends on the details of the generalizations. For example, in single-item auction, competition and...
Next generation cellular networks are expected to support a massive data traffic volume and satisfy a vast number of users that have latency-critical quality-of-service expectations. Towards serving this demand, it is envisaged that the interference management problem will be the main bottleneck due to the likeliness of a heavily interfering...
At its core, the purpose of microscopy is to make objects and their underlying structures visible under high magnification. With the remarkable progress of electron microscopy, the sub-micron “high” magnification of light microscopy has been completely refashioned to encompass subatomic length scales. Unfortunately, higher-magnification does little to negate existing interpretability...
Existing nonlinear optimization methods have proven reliable over the past few decades for a wide range of applications but have critically relied on accurate function and gradient evaluations. Modern nonlinear optimization problems arising from machine learning and scientific computing applications are increasingly complex and large scale, which make accurate evaluations...
Language models are the foundation of many natural language tasks such as machine translation, speech recognition, and dialogue systems. Modeling the probability distributions of text accurately helps capture the structures of language and extract valuable information contained in various corpora. In recent years, many advanced models have achieved state-of-the-art performance...