diff --git a/decoders/swig/ctc_decoders.cpp b/decoders/swig/ctc_decoders.cpp
index e86bfe0f2c554e56f54283db79444985f863fb41..86598eee6e0513d74111a3702586549e59ef1464 100644
--- a/decoders/swig/ctc_decoders.cpp
+++ b/decoders/swig/ctc_decoders.cpp
@@ -18,7 +18,7 @@ std::string ctc_greedy_decoder(
     const std::vector<std::string> &vocabulary) {
   // dimension check
   size_t num_time_steps = probs_seq.size();
-  for (size_t i = 0; i < num_time_steps; i++) {
+  for (size_t i = 0; i < num_time_steps; ++i) {
     VALID_CHECK_EQ(probs_seq[i].size(),
                    vocabulary.size() + 1,
                    "The shape of probs_seq does not match with "
@@ -28,7 +28,7 @@ std::string ctc_greedy_decoder(
   size_t blank_id = vocabulary.size();
 
   std::vector<size_t> max_idx_vec;
-  for (size_t i = 0; i < num_time_steps; i++) {
+  for (size_t i = 0; i < num_time_steps; ++i) {
     double max_prob = 0.0;
     size_t max_idx = 0;
     for (size_t j = 0; j < probs_seq[i].size(); j++) {
@@ -41,14 +41,14 @@ std::string ctc_greedy_decoder(
   }
 
   std::vector<size_t> idx_vec;
-  for (size_t i = 0; i < max_idx_vec.size(); i++) {
+  for (size_t i = 0; i < max_idx_vec.size(); ++i) {
     if ((i == 0) || ((i > 0) && max_idx_vec[i] != max_idx_vec[i - 1])) {
       idx_vec.push_back(max_idx_vec[i]);
     }
   }
 
   std::string best_path_result;
-  for (size_t i = 0; i < idx_vec.size(); i++) {
+  for (size_t i = 0; i < idx_vec.size(); ++i) {
     if (idx_vec[i] != blank_id) {
       best_path_result += vocabulary[idx_vec[i]];
     }
@@ -65,7 +65,7 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
     Scorer *ext_scorer) {
   // dimension check
   size_t num_time_steps = probs_seq.size();
-  for (size_t i = 0; i < num_time_steps; i++) {
+  for (size_t i = 0; i < num_time_steps; ++i) {
     VALID_CHECK_EQ(probs_seq[i].size(),
                    vocabulary.size() + 1,
                    "The shape of probs_seq does not match with "
@@ -111,7 +111,7 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
   for (size_t time_step = 0; time_step < num_time_steps; time_step++) {
     std::vector<double> prob = probs_seq[time_step];
     std::vector<std::pair<int, double>> prob_idx;
-    for (size_t i = 0; i < prob.size(); i++) {
+    for (size_t i = 0; i < prob.size(); ++i) {
       prob_idx.push_back(std::pair<int, double>(i, prob[i]));
     }
 
@@ -134,7 +134,7 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
       if (cutoff_prob < 1.0) {
         double cum_prob = 0.0;
         cutoff_len = 0;
-        for (size_t i = 0; i < prob_idx.size(); i++) {
+        for (size_t i = 0; i < prob_idx.size(); ++i) {
           cum_prob += prob_idx[i].second;
           cutoff_len += 1;
           if (cum_prob >= cutoff_prob) break;
@@ -145,7 +145,7 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
           prob_idx.begin(), prob_idx.begin() + cutoff_len);
     }
     std::vector<std::pair<size_t, float>> log_prob_idx;
-    for (size_t i = 0; i < cutoff_len; i++) {
+    for (size_t i = 0; i < cutoff_len; ++i) {
       log_prob_idx.push_back(std::pair<int, float>(
           prob_idx[i].first, log(prob_idx[i].second + NUM_FLT_MIN)));
     }
@@ -155,7 +155,7 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
       auto c = log_prob_idx[index].first;
       float log_prob_c = log_prob_idx[index].second;
 
-      for (size_t i = 0; i < prefixes.size() && i < beam_size; i++) {
+      for (size_t i = 0; i < prefixes.size() && i < beam_size; ++i) {
         auto prefix = prefixes[i];
 
         if (full_beam && log_prob_c + prefix->score < min_cutoff) {
@@ -222,14 +222,14 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
                        prefixes.end(),
                        prefix_compare);
 
-      for (size_t i = beam_size; i < prefixes.size(); i++) {
+      for (size_t i = beam_size; i < prefixes.size(); ++i) {
         prefixes[i]->remove();
       }
     }
   }  // end of loop over time
 
   // compute aproximate ctc score as the return score
-  for (size_t i = 0; i < beam_size && i < prefixes.size(); i++) {
+  for (size_t i = 0; i < beam_size && i < prefixes.size(); ++i) {
     double approx_ctc = prefixes[i]->score;
 
     if (ext_scorer != nullptr) {
@@ -249,14 +249,14 @@ std::vector<std::pair<double, std::string>> ctc_beam_search_decoder(
   // allow for the post processing
   std::vector<PathTrie *> space_prefixes;
   if (space_prefixes.empty()) {
-    for (size_t i = 0; i < beam_size && i < prefixes.size(); i++) {
+    for (size_t i = 0; i < beam_size && i < prefixes.size(); ++i) {
       space_prefixes.push_back(prefixes[i]);
     }
   }
 
   std::sort(space_prefixes.begin(), space_prefixes.end(), prefix_compare);
   std::vector<std::pair<double, std::string>> output_vecs;
-  for (size_t i = 0; i < beam_size && i < space_prefixes.size(); i++) {
+  for (size_t i = 0; i < beam_size && i < space_prefixes.size(); ++i) {
     std::vector<int> output;
     space_prefixes[i]->get_path_vec(output);
     // convert index to string
@@ -301,7 +301,7 @@ ctc_beam_search_decoder_batch(
 
   // enqueue the tasks of decoding
   std::vector<std::future<std::vector<std::pair<double, std::string>>>> res;
-  for (size_t i = 0; i < batch_size; i++) {
+  for (size_t i = 0; i < batch_size; ++i) {
     res.emplace_back(pool.enqueue(ctc_beam_search_decoder,
                                   probs_split[i],
                                   beam_size,
@@ -313,7 +313,7 @@ ctc_beam_search_decoder_batch(
 
   // get decoding results
   std::vector<std::vector<std::pair<double, std::string>>> batch_results;
-  for (size_t i = 0; i < batch_size; i++) {
+  for (size_t i = 0; i < batch_size; ++i) {
     batch_results.emplace_back(res[i].get());
   }
   return batch_results;
diff --git a/models/aishell/download_model.sh b/models/aishell/download_model.sh
new file mode 100644
index 0000000000000000000000000000000000000000..4368ee55af8c062c2ac5d7e1bcc56d086a186887
--- /dev/null
+++ b/models/aishell/download_model.sh
@@ -0,0 +1,19 @@
+#! /usr/bin/bash
+
+source ../../utils/utility.sh
+
+URL='http://cloud.dlnel.org/filepub/?uuid=6c83b9d8-3255-4adf-9726-0fe0be3d0274'
+MD5=28521a58552885a81cf92a1e9b133a71
+TARGET=./aishell_model.tar.gz
+
+
+echo "Download Aishell model ..."
+download $URL $MD5 $TARGET
+if [ $? -ne 0 ]; then
+    echo "Fail to download Aishell model!"
+    exit 1
+fi
+tar -zxvf $TARGET
+
+
+exit 0
diff --git a/models/librispeech/download_model.sh b/models/librispeech/download_model.sh
index 4408f6c1c7f648a8b3688959a782dfaaee628711..b5fcd7d8c133ea27d1f10d90b8d09e15821a220e 100644
--- a/models/librispeech/download_model.sh
+++ b/models/librispeech/download_model.sh
@@ -2,9 +2,8 @@
 
 source ../../utils/utility.sh
 
-# TODO: add urls
-URL='to-be-added'
-MD5=5b4af224b26c1dc4dd972b7d32f2f52a
+URL='http://cloud.dlnel.org/filepub/?uuid=17404caf-cf19-492f-9707-1fad07c19aae'
+MD5=ea5024a457a91179472f6dfee60e053d
 TARGET=./librispeech_model.tar.gz
 
 
diff --git a/models/lm/download_lm_ch.sh b/models/lm/download_lm_ch.sh
new file mode 100644
index 0000000000000000000000000000000000000000..7f1c47a27641cb07e4ab638b2949e667abcc473d
--- /dev/null
+++ b/models/lm/download_lm_ch.sh
@@ -0,0 +1,18 @@
+#! /usr/bin/bash
+
+source ../../utils/utility.sh
+
+URL=http://cloud.dlnel.org/filepub/?uuid=d21861e4-4ed6-45bb-ad8e-ae417a43195e
+MD5="29e02312deb2e59b3c8686c7966d4fe3"
+TARGET=./zh_giga.no_cna_cmn.prune01244.klm
+
+
+echo "Download language model ..."
+download $URL $MD5 $TARGET
+if [ $? -ne 0 ]; then
+    echo "Fail to download the language model!"
+    exit 1
+fi
+
+
+exit 0
diff --git a/requirements.txt b/requirements.txt
index 131f75ff47e003f3b44f4a62f1431cf13d4f44a4..e104f633c792ee9be4f2864e99aea64924a1e2fb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,4 +2,3 @@ scipy==0.13.1
 resampy==0.1.5
 SoundFile==0.9.0.post1
 python_speech_features
-https://github.com/luotao1/kenlm/archive/master.zip
diff --git a/utils/utility.sh b/utils/utility.sh
index aa0ec002bca0597bd61728180e2fb1ccdd02e5d6..f242b7640b6ac2af42aaa450261ddfb43bf7357e 100644
--- a/utils/utility.sh
+++ b/utils/utility.sh
@@ -11,10 +11,9 @@ download() {
         fi
     fi
 
-    wget -c $URL -P `dirname "$TARGET"`
+    wget -c $URL -O "$TARGET"
     md5_result=`md5sum $TARGET | awk -F[' '] '{print $1}'`
     if [ ! $MD5 == $md5_result ]; then
-        echo "Fail to download the language model!"
         return 1
     fi
 }