The first phase of a dog park to honor a sailor from South Sioux City killed in the middle east war will open this weekend.   The dedication is on Sunday for the John Douangdara Memorial War Dog Park.    Petty Officer 1st Class Douangdara was among 30 Americans killed when a military helicopter was shot down in Afghanistan last August. He was a Navy Special Warfare member who handled a dog.   The park will feature of statue of Douangdara and Bart, his military dog. It will be open to dogs after Sunday's dedication.