qgis - How to use Threads in PyQgis, mainly to keep UI active?

I'm trying to develop a plugin, which does heavy computations and as a result, user interface becomes inactive. I know that I should use threads to keep the UI alive (specifically, I have a progress bar that I want to update), but my experience with threads is very limited.

I was wondering if there are any good tutorials, or code snippets with documentation that cover this issue. sample of my code so far (without threads):

    def initGui(self):

    # Create action that will start plugin configuration
    self.action = QAction(
        QIcon(":/plugins/lts/icon.png"),
        u"LTS calculator", self.iface.mainWindow())
    # connect the action to the run method
    self.action.triggered.connect(self.run)

    # Add toolbar button and menu item
    self.iface.addToolBarIcon(self.action)
    self.iface.addPluginToMenu(u"<S Calculator", self.action)


    # QtCore.QObject.connect(self.dlg.ui.find_cc, QtCore.SIGNAL("clicked()"), self.find_connected_components)

    QtCore.QObject.connect(self.dlg.ui.process_Button,QtCore.SIGNAL("clicked()"), self.process)
    # QtCore.QObject.connect(self.dlg.ui.layerCombo,QtCore.SIGNAL("currentIndexChanged(int)"), self.update_lts_field)
    QtCore.QObject.connect(self.dlg.ui.layerCombo,QtCore.SIGNAL("activated (int)"), self.update_lts_field)
    QtCore.QObject.connect(self.dlg.ui.find_cc_Button,QtCore.SIGNAL("clicked()"), self.find_connected_components)


    self.update_ui()

    self.layers = self.iface.legendInterface().layers()  # store the layer list 
    # self.dlg.ui.layerCombo.clear()  # clear the combo 
    for layer in self.layers:    # foreach layer in legend 
        self.dlg.ui.layerCombo.addItem( layer.name() )    # add it t


   def process(self):
    """ Calculates Stress for the selected layer"""
    index = self.dlg.ui.layerCombo.currentIndex() 
    if index < 0: 

        # it may occur if there's no layer in the combo/legend 
        pass
    else: 
        layer = self.dlg.ui.layerCombo.itemData(index) 
    # layer = QgsVectorLayer(self.fileName, "layer_name", "ogr")
    nFeat = layer.featureCount()
    layer.startEditing()
    ...
    street.compute_LTS()
        if street.LTS != None :

            i+=1
            j=ceil(i/(nFeat/100))
            self.dlg.ui.progress_bar.setValue(j)
            layer.updateFeature(feature)
# run method that performs all the real work
def run(self):
    # show the dialog
    self.dlg.show()
    self.dlg.ui.progress_bar.setValue(0)
    self.dlg.ui.progressBar.setValue(0)

    self.dlg.ui.layerCombo.clear()
    self.dlg.ui.lts_combo.clear()

    layers = QgsMapLayerRegistry.instance().mapLayers().values()
    for layer in layers:
        if layer.type() == QgsMapLayer.VectorLayer and layer.geometryType() == QGis.Line:
            self.dlg.ui.layerCombo.addItem( layer.name(), layer ) 

    self.update_lts_field()
    # Run the dialog event loop

    result = self.dlg.exec_()
    # See if OK was pressed
    if result == 1:
        # do something useful (delete the line containing pass and
        # substitute with your code)
        pass

Thanks