Principal, User Research

This is where your work makes a difference. At Baxter, we believe every person—regardless of who they are or where they are from—deserves a chance to live a healthy life. It was our founding belief in 1931 and continues to be our guiding principle. We are redefining healthcare delivery to make a greater impact today, tomorrow, and beyond. Our Baxter colleagues are united by our Mission to Save and Sustain Lives. Together, our community is driven by a culture of courage, trust, and collaboration. Every individual is empowered to take ownership and make a meaningful impact. We strive for efficient and effective operations, and we hold each other accountable for delivering exceptional results. Here, you will find more than just a job—you will find purpose and pride. Your Role at Baxter This role involves collaborating with clinicians, engineers, and cross-functional partners to improve usability, safety, and efficiency for hospital beds, mobile and overhead patient lift systems, and other product portfolios. Your efforts will directly support developing new products and sustaining engineering initiatives. When you come on board at Baxter as a Principal Engineer, Human Factors, you will apply your analytical methodology to pinpoint risks and opportunities for innovation promptly. Nimble and ready to act, you maintain composure in high-pressure situations. What you'll be doing Lead and drive implementation of training, continuous improvement efforts, and overall initiatives to improve functional outcomes. Conduct user research, usability testing, and user-centered development activities to ensure our products meet customers' needs and mitigate risk effectively. Develop and maintain human fact

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 130 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com . Reddit’s Ads Design & Research team shapes the end-to-end advertising experience across advertiser tools, consumer ad experiences, measurement, and the systems that connect them. We’re looking for a Principal UX Engineer who sees code as a product-design medium: a way to make ideas tangible, connect prototypes to real systems and data, and help teams move from exploration to engineering-ready product direction faster. This is a strategic, hands-on role at the intersection of design and engineering. You’ll work across Reddit Ads to shape product direction, build production-adjacent prototypes and tools, and help establish UX Engineering as a capability for the Ads Design team. You’ll partner closely with Design, Research, Product, Engineering, and Data Science while staying deeply involved in the craft. What You’ll Do Define and lead the UX Engineering strategy across multiple areas of Reddit Ads. Build high-quality functional prototypes, workflow tools, agents, and PR-ready product experiences that help teams explore ideas, test assumptions, and move faster from design intent to engineering review. Partner with senior cross-functional leaders to shape product direction and bring clarity to complex, ambiguous opportunities. Create reusable tools, systems, components, and workflows that make it easier to move from design and research into production. Raise the bar for interaction quality, accessibility, performance, and technical craft across the Ads experience. Build AI-native workflows, skills, agents, and tools tha

What you’ll do Partner with medical image reconstruction scientists / engineers to build ML components that improve reconstruction quality, speed, robustness, or quantitative accuracy. Define training/evaluation pipelines, datasets, and metrics that map to user needs and design requirements. Productionize models: inference performance, reproducibility, monitoring for drift/regressions, and safe fallbacks. Collaborate on hybrid algorithms, incorporating physics and learned priors, denoisers, learned regularizers, and quality estimation. Help build tooling for rapid experimentation as well as rigorous verification of algorithm changes. What we’re looking for Strong applied ML experience plus comfort with signal processing / imaging or adjacent domains. Ability to move fluidly between research prototypes and production-quality systems. Strong evaluation discipline: metrics, ablations, data leakage avoidance, and reproducibility. A demonstrated track record of applying ML to physics-based or inverse problems (i.e., shipped projects, a portfolio, or publications.) Useful experience ML for imaging/inverse problems (or adjacent) with strong evaluation discipline and comfort with GPU performance constraints. Pragmatic production mindset: reproducible training/inference, regression testing, and safe deployment in high-stakes contexts. A background in computational physics or scientific computing. Leverage ML-based methods such as PiNNs and Neural Operators to solve partial differential equations arising in ultrasound simulation and imaging. Experience in Agentic-SciML is a plus. Hands-on experience with data curation for ML: building datasets from messy, real-world sources, defining ground truth, and managing labeling or simulation pipelines. Background in data assimilation: combining observations with physics-based models (Kalman filtering, variational methods, ensemble approaches, or learned variants).

About the Team Security is at the foundation of OpenAI’s mission to ensure that artificial general intelligence benefits all of humanity. The Security team protects OpenAI’s technology, people, and products. We are technical in what we build but are operational in how we do our work, and are committed to supporting all products and research at OpenAI. Our Security team tenets include: prioritizing for impact, enabling researchers, preparing for future transformative technologies, and engaging a robust security culture. About the Role OpenAI is seeking a Principal Security Engineer to join our Infrastructure Security (InfraSec) team. InfraSec protects the foundations of OpenAI’s research and production environments, spanning GPU supercomputing clusters, multi-cloud infrastructure, datacenters, networking, storage, and the critical services that power our frontier AI models. Our charter includes securing everything from bare-metal hardware and firmware, to Kubernetes clusters and service meshes, to data storage and access pathways for highly sensitive model weights and user data. As a principal engineer, you will set technical direction and drive execution on high-impact infrastructure security programs, partnering across various orgs at OpenAI to deliver durable controls that raise the security bar at OpenAI scale. In this role, you will: Own end-to-end security outcomes for one or more critical infrastructure areas, including multi-quarter strategy, roadmap, and delivery. Design and build security controls across diverse layers (e.g., physical hardware, firmware/BMC, OS, Kubernetes, networks, and CI/CD) to defend against sophisticated adversaries and insider threats. Lead cross-functional programs to deploy security enhancements and control changes across broad-scale infrastructure, balancing security guarantees with reliability and velocity. Take a generalist approach to building security controls, balancing a mix of security expertise and broad technical skillsets

About the Team Security is at the foundation of OpenAI’s mission to ensure that artificial general intelligence benefits all of humanity. The Security team protects OpenAI’s technology, people, and products. We are technical in what we build but operational in how we execute, and we support every product and research effort at OpenAI. Our tenets include prioritizing for impact, enabling researchers and developers, preparing for future transformative technologies, and fostering a strong, collaborative security culture. About the Role OpenAI is seeking a Principal Software Engineer to join the Infrastructure Security (InfraSec) team. InfraSec safeguards the core of OpenAI’s research and production environments: GPU supercomputing clusters, multi-cloud infrastructure, datacenters, networking, storage, and the critical services that power our frontier AI models. Our charter spans everything from bare-metal hardware and firmware to Kubernetes clusters, service meshes, and the data pathways that carry highly sensitive model weights and user data. As a Principal Software Engineer, you will set technical direction and drive execution of critical foundational services, such as authentication systems, egress/ingress proxies, access brokers, and key management platforms, that demand high standards of reliability, scalability, and software craftsmanship. These systems form the security backbone of OpenAI’s customer and supercomputing environment and must remain robust under intense scale and adversarial pressure. In this role, you will: Own the architecture and roadmap for one or more core security services (e.g., authN/Z, policy enforcement, secure proxies, key management), taking them from design to rollout to long-term operation. Design and implement planet-scale security systems that provide strong guarantees across hardware, operating systems, Kubernetes, networks, and CI/CD: balancing security, reliability, latency, and developer ergonomics. Lead cross-functional launches

Every day, tens of millions of people come to Roblox to explore, create, play, learn, and connect with friends in 3D immersive digital experiences– all created by our global community of developers and creators. At Roblox, we’re building the tools and platform that empower our community to bring any experience that they can imagine to life. Our vision is to reimagine the way people come together, from anywhere in the world, and on any device. We’re on a mission to connect a billion people with optimism and civility, and looking for amazing talent to help us get there. A career at Roblox means you’ll be working to shape the future of human interaction, solving unique technical challenges at scale, and helping to create safer, more civil shared experiences for everyone. With Roblox’s daily active users growing at a record pace, we are seeking experienced machine learning researchers who thrive on solving complex challenges and designing scalable, ground breaking solutions. In this role, you will innovate on LLMs, VLMs, autoregressive models, or other large models for user understanding, content understanding, recommendation, and agentic search. Your work will lay the foundation for personalizing user experiences, enhancing engagement and retention, and driving growth within the creator ecosystem. In search and discovery, you will contribute to the core systems that enable users to discover and interact with experiences across Roblox. On Search, that work spans the end-to-end user search journey, covering query suggestions, autocomplete, and retrieval and ranking. These systems drive exploration and engagement across all surfaces, helping users find relevant and exciting content. Looking ahead, our team aims to innovate further by developing auto-generated summaries, images, and videos from experience content to improve discoverability and inspire user exploration. Our mission is to connect a billion users with the best content and connections at the right