Soak the ribs: Submerge the short ribs in cold water for 30 minutes to remove excess blood. Drain well and pat dry with paper towels.
Mix the marinade: Whisk together soy sauce, brown sugar, grated Asian pear, garlic, ginger, sesame oil, and black pepper in a bowl. Pour over the ribs and marinate at least 1 hour, or overnight in the fridge.
Sear the short ribs: Heat vegetable oil in a Dutch oven over medium-high heat. Sear the ribs 2-3 minutes per side until deep golden brown on the edges, working in batches if needed.
Add the braising liquid: Pour the marinade over the seared ribs and add water or broth until the ribs are mostly submerged. Bring to a gentle simmer over medium heat.
Cover and braise: Reduce heat to low, cover the pot, and simmer for 90 minutes, stirring occasionally. The liquid should bubble gently, not boil hard.
Check for tenderness: After 90 minutes, press a fork into a rib. It should pull apart easily and begin separating from the bone.
Add the vegetables: Stir in the carrots and daikon radish and continue simmering uncovered for 25-30 minutes, until the vegetables are fork-tender and the sauce has thickened slightly.
Rest the pot: Remove from heat and let the pot sit uncovered for 10 minutes so the sauce settles and thickens further.
Garnish and serve: Sprinkle sliced green onions and sesame seeds over the top. Spoon the ribs and sauce over steamed rice to serve.