KYIV, Ukraine — Ukraine’s new military chief said Friday his immediate goals are to improve the rotation of troops out of the front lines and harness the power of new technology in the fight against Russia’s invasion . Col. Gen. Oleksandr Syrskyi, who previously was the commander of Ukraine’s ground forces, spoke a day after President Volodymyr Zelenskyy put him in charge of the battlefield campaign against Russia’s invasion. “New tasks are on the agenda,” Syrskyi said on his Telegram channel.