Edit in JSFiddle

<div data-bind="foreach: techniques">
    <label>
        <input type="radio" data-bind="value: value, checked: $parent.selectedTechnique" />
        <span data-bind="text: text"></span>
    </label>
</div>
<div data-bind="text: selectedTechniqueText"></div>

function ViewModel() {
    var self = this;
    self.techniques = [{
        text: "ASP.NET Web Forms",
        value: "webforms"
    }, {
        text: "ASP.NET MVC",
        value: "mvc"
    }, {
        text: "ASP.NET Web API",
        value: "webapi"
    }];

    self.selectedTechnique = ko.observable("");
    self.selectedTechniqueText = ko.computed(function () {
        var search = self.selectedTechnique().toLowerCase();
        if (!search) {
            return null;
        } else {
            var matchedItem = ko.utils.arrayFirst(self.techniques, function (item) {
                return ko.utils.stringStartsWith(item.value.toLowerCase(), search);
            });
            return matchedItem.text;
        }
    });
}

ko.applyBindings(new ViewModel());