public static SignalModel GetSignalModel(string nameSpace, string signalName)
        {
            SignalModel        model   = null;
            SignalModelLibrary library = null;
            SignalManager      sm      = Instance;

            if (sm._signalModelLibraryCache.ContainsKey(nameSpace))
            {
                library = sm._signalModelLibraryCache[nameSpace];
            }
            else
            {
                SignalDAO    dao    = new SignalDAO();
                dbTSFLibrary tsfLib = dao.getTSFLibraryByNameSpace(nameSpace);
                if (tsfLib != null)
                {
                    string       content = tsfLib.content;
                    MemoryStream ms      = new MemoryStream(Encoding.UTF8.GetBytes(content));
                    library = new SignalModelLibrary(ms);
                    sm._signalModelLibraryCache.Add(nameSpace, library);
                }
            }
            if (library != null)
            {
                model = library.GetSignalModel(signalName);
            }

            return(model);
        }