Charles Douglas Harper

Charles Douglas “Doug” Harper passed away peacefully at age 73 on July 10, 2025 after a long illness.

Doug was born on December 7, 1951 in Englewood, New Jersey to Charles H. and Elva Darlene Schoaff Harper. Charles and Elva were studying to become Methodist missionaries at the time and in 1953 they set sail for Pusan, Korea where Doug spent his formative years.

After attending Korean kindergarten, Doug was homeschooled for a few years until the US military brought their dependents to Korea. Doug and his elder sister were able to attend the military provided school through junior high. Next, Doug attended Seoul Foreign School, boarding in the dormitory. There Doug played on the soccer team and was active in the Boy Scouts as bugler. He advanced to Eagle Scout. He also won a speech contest between American students abroad on the subject of freedom and was flown to the United States to be awarded personally by President Johnson. He graduated high school in 1969.

Doug’s undergraduate studies were spent at Illinois Wesleyan University and Illinois State University. He double majored in Philosophy and Mathematics, earning a BS degree and graduating with honors in 1975. During that time he was employed by State Farm Insurance Company to computerize their corporate headquarters. He and Janet Cawley met in college and they married in 1976. The newlyweds undertook their graduate studies living in married student housing at the University of Illinois, Urbana-Champaign, where they welcomed their daughters Alethea and Sonya. He earned his MS in Mathematics in 1981 and PhD in Mathematical Logic in 1987.

Doug’s career was focused on computer science research and development, especially the application of formal methods to software engineering for computer security and avionics. He worked for companies that contracted primarily with the Defense Department and NASA, spanning a broad spectrum of applications, many highly sensitive. His first position was Senior Principal Scientist with Odyssey Research Associates in Ithaca, NY where he and Janet raised the family, and his last position was Senior First Scientist with Rockwell Collins in Cedar Rapids.

Doug was a loving father, son, and brother. He was a deep thinker with an encyclopedic knowledge of many subjects including history, geography, music, and literature. He was a writer, a martial artist, and a lover of cats, dogs, and “dad jokes.” He loved to hike, camp, and to sing barbershop.

He is survived by his sisters, Merridee (David) and Kay; his daughters, Alethea (Kevin) and Sonya (Mike); his granddaughters, Frances, Lily, and Zoe; his nephew, Krispin; his niece, Helen (Adam); and his great-niece, Zella.

Visitation will be held Wednesday, August 6, 2025 from 10:00 AM to 11:00 AM at Davison-Fulton Woodland Chapel, 2021 North University Street, Peoria, IL 61604. A funeral service will follow at 11:00 AM. Burial will be at Cottonwood Cemetery, 12721 W Cottonwood Rd, Hanna City, Illinois 61536.

If you wish to send flowers, you can order directly from Beck’s Florist, Inc. at https://www.becksflorist.net/ If you would prefer to send a memorial donation, you may make it to SAMS Stray Animal Midway Shelter. https://www.samsrescue.org/