Senior Ontologist

Description Are you passionate about building solutions for our greatest national security challenges? Are you searching for engaging work with an employer that prioritizes impact, innovation, and personal development? Do you value working in a creative and collaborative environment? If so, we’re looking for someone like you to join our team at APL. The Threat Analytic Systems (QAI) Group wants talented staff who can work as part of a team to provide our nation with ground‑breaking capabilities that bridge the gaps between data, real‑world events and people, and prediction of events of national importance. We need talented engineers, scientists, and ontologists with curiosity and a drive for learning! As a member of our team... You will work on a team with software engineers and data scientists to build ontologies and capabilities for applied national security mission needs. You will provide expert evaluation and review of ontology content. You will engage stakeholders to determine ontology requirements. You will work with subject matter experts to craft ontology content. You will contribute to and implement quality assurance and validation practices. Qualifications You’ll meet our minimum requirements if you... Have a Master's degree in a field relevant to Ontology. Relevant degree fields may include Philosophy, Computer Science, Cognitive Science, Public / Social Policy, Mathematics, Logic, or Linguistics. Are proficient with any of the following: Ontology Web Language (OWL), Resource Description Framework Schema (RDFs), and Resource Description Framework (RDF) Are proficient with SPARQL Have experience building domain ontologies based on a top‑level ontology Are able to weigh tradeoffs between semantic expressivity and project‑specific implementation strategies Have experience with Python Are familiar with ontology editors (e.g., TopBraid Composer, Protege, ROBOT), or ontology editing software packages (e.g. rdflib, Apache Jena, Sesame, RDF4J) Have experience with formal representations of logical reasoning and inference Can work with loosely defined or high‑level requirements Can work on multiple dynamic projects to support evolving national security requirements Have strong problem solving, analytical, and organizational skills Have demonstrated initiative Have experience working successfully independently or within a team environment Have excellent written and verbal communication skills Have the ability to obtain a TS/SCI level security clearance. If selected, you will be subject to a government security clearance investigation and must meet the requirements for access to classified information. Eligibility requirements include U.S. citizenship. You’ll go above and beyond our minimum requirements if you have... A PhD in a field relevant to Ontology. Relevant degree fields may include Philosophy, Computer Science, Cognitive Science, Public / Social Policy, Mathematics, Logic, or Linguistics Experience working with a software engineering team to deliver ontology‑driven software features Experience with any of the following: Basic Formal Ontology (BFO); The Common Core Ontologies (CCO); W3C standards such as SOSA/SSN and the Time Ontology; ontologies in the Open Biological and Biomedical (OBO) Foundry; as well as other semantic web standards, such as Dublin Core, SKOS, QUDT, and GeoSPARQL Experience with triple stores or graph databases (e.g., GraphDB, Stardog, Jena Fuseki) Experience using AI tools to generate high quality ontology content Experience developing AI tools that use ontologies or knowledge graphs Experience with semantic validation languages (e.g. SHACL, SPIN) Experience with software version management using GIT Experience with machine learning, natural language processing, or in the normalization/integration of heterogeneous data sources Coursework in data structures, databases, metaphysics, knowledge representation, algorithms, mathematical logic, mereotopology, or software programming Experience with project management and/or leading technical teams About Us The Johns Hopkins University Applied Physics Laboratory (APL) brings world‑class expertise to our nation's most critical defense, security, space and science challenges. While we are dedicated to solving complex challenges and pioneering new technologies, what makes us truly outstanding is our culture. We offer a vibrant, welcoming atmosphere where you can bring your authentic self to work, continue to grow, and build strong connections with inspiring teammates. At APL, we celebrate our differences of perspectives and encourage creativity and bold, new ideas. Our employees enjoy generous benefits, including a robust education assistance program, unparalleled retirement contributions, and a healthy work/life balance. APL's campus is located in the Baltimore‑Washington metro area. Learn more about our career opportunities at All qualified applicants will receive consideration for employment without regard to race, creed, color, religion, sex, gender identity or expression, sexual orientation, national origin, age, physical or mental disability, genetic information, veteran status, occupation, marital or familial status, political opinion, personal appearance, or any other characteristic protected by applicable law. APL is committed to providing reasonable accommodation to individuals of all abilities, including those with disabilities. If you require a reasonable accommodation to participate in any part of the hiring process, please contact View email address on click.appcast.io. The referenced pay range is based on JHU APL's good faith belief at the time of posting. Actual compensation may vary based on factors such as geographic location, work experience, market conditions, education/training and skill level with consideration for internal parity. For salaried employees scheduled to work less than 40 hours per week, annual salary will be prorated based on the number of hours worked. APL may offer bonuses or other forms of compensation per internal policy and/or contractual designation. Additional compensation may be provided in the form of a sign‑on bonus, relocation benefits, locality allowance or discretionary payments for exceptional performance. APL provides eligible staff with a comprehensive benefits package including retirement plans, paid time off, medical, dental, vision, life insurance, short‑term disability, long‑term disability, flexible spending accounts, education assistance, and training and development. Applications are accepted on a rolling basis. Minimum Rate $100,000 Annually Maximum Rate $245,000 Annually #J-18808-Ljbffr The Johns Hopkins University Applied Physics Laboratory