radio and ng-model

HTML

<body ng-app="app">
  <div ng-controller='controller'>
     chosen = {{obj.chosen}}
    <br><br>
    chosen = <input type="text" ng-model="obj.chosen" />
    <br><br>

    <div ng-repeat="item in obj.list">
      <label>
                <input type="radio" name="connection" ng-model="obj.chosen" value="{{item}}"
                />
                {{item.name}}
            </label>
    </div>
  </div>
</body>

JavaScript

app = angular.module('app', []);

app.controller('controller', function($scope) {
  $scope.obj = {};
  $scope.obj.chosen = {id:2,name:"titi"};
  $scope.obj.list = [{
    id: 1,
    name: "toto"
  }, {
    id: 2,
    name: "titi"

  }, {
    id: 3,
    name: "tutu"
  }];

});