var result = {
    time: [],
    workstations : [],
    workers: []
};
for (var i = 0; i < data.length; ++i) {
    !~result.time.indexOf(JSON.stringify([data[i][0], data[i][1]])) && result.time.push(JSON.stringify([data[i][0], data[i][1]]));
    !~result.workstations.indexOf(data[i][2]) && result.workstations.push(data[i][2]);
    !~result.workers.indexOf(data[i][3])&& result.workers.push(data[i][3]);
}
console.log(result);