diff --git a/chamsin/src/analogic/Transistor.cpp b/chamsin/src/analogic/Transistor.cpp
index 8db0dcde..894088dd 100644
--- a/chamsin/src/analogic/Transistor.cpp
+++ b/chamsin/src/analogic/Transistor.cpp
@@ -129,7 +129,7 @@ void Transistor::createLayout() {
     if (toto > _l) {
         dx30 = rwCont;
         dy30 = dx30;
-        y30 = _w + DbU::max(rdActiveCont, rdActivePoly + rePolyCont); 
+        y30 = _w + max(rdActiveCont, rdActivePoly + rePolyCont); 
     } else {
         dx30 = dx00 - 2*rePolyCont;
         dy30 = rwCont;
diff --git a/chamsin/src/technology/ATechnology.cpp b/chamsin/src/technology/ATechnology.cpp
index 93bb32d9..fd6c975e 100644
--- a/chamsin/src/technology/ATechnology.cpp
+++ b/chamsin/src/technology/ATechnology.cpp
@@ -90,7 +90,7 @@ void ATechnology::print() {
     for (OneLayerPhysicalRules::iterator olprit = _oneLayerPhysicalRules.begin();
             olprit != _oneLayerPhysicalRules.end();
             olprit++) {
-        Layer* layer = olprit->first;
+        const Layer* layer = olprit->first;
         cout << "   o layer " << layer << endl; 
         printPhysicalRules(olprit->second);
         cout << endl;
@@ -99,8 +99,8 @@ void ATechnology::print() {
     for (TwoLayersPhysicalRules::iterator tlprit = _twoLayersPhysicalRules.begin();
             tlprit != _twoLayersPhysicalRules.end();
             tlprit++) {
-        Layer* layer1 = tlprit->first.first;
-        Layer* layer2 = tlprit->first.second;
+        const Layer* layer1 = tlprit->first.first;
+        const Layer* layer2 = tlprit->first.second;
         cout << "   o layer1 " << layer1 << endl; 
         cout << "   o layer2 " << layer2 << endl; 
         printPhysicalRules(tlprit->second);
@@ -118,11 +118,11 @@ const ATechnology::PhysicalRule* ATechnology::getPhysicalRule(const Name& name)
 }
 
 const ATechnology::PhysicalRule* ATechnology::getPhysicalRule(const Name& name, const Layer* layer) const {
-    OneLayerPhysicalRules::iterator olprit = _oneLayerPhysicalRules.find(layer);
+    OneLayerPhysicalRules::const_iterator olprit = _oneLayerPhysicalRules.find(layer);
     if (olprit == _oneLayerPhysicalRules.end()) {
         throw Error("Cannot find Physical Rules for layer " + getString(layer->getName()));
     }
-    PhysicalRules& physicalRules = olprit->second;
+    const PhysicalRules& physicalRules = olprit->second;
     PhysicalRule searchPR(name, 0, "");
     PhysicalRules::iterator prit = physicalRules.find(&searchPR);
     if (prit == physicalRules.end()) {
@@ -135,11 +135,15 @@ const ATechnology::PhysicalRule* ATechnology::getPhysicalRule(
         const Name& name,
         const Layer* layer1,
         const Layer* layer2) const {
-    TwoLayerPhysicalRules::iterator tlprit = _twoLayerPhysicalRules.find(layer);
-    if (olprit == _oneLayerPhysicalRules.end()) {
-        throw Error("Cannot find Physical Rules for layer " + getString(layer->getName()));
+    LayerPair searchLayerPair(layer1, layer2);
+    TwoLayersPhysicalRules::const_iterator tlprit = _twoLayersPhysicalRules.find(searchLayerPair);
+    if (tlprit == _twoLayersPhysicalRules.end()) {
+        throw Error("Cannot find Physical Rules for layers " +
+                getString(layer1->getName()) +
+                " and " +
+                getString(layer2->getName()));
     }
-    PhysicalRules& physicalRules = olprit->second;
+    const PhysicalRules& physicalRules = tlprit->second;
     PhysicalRule searchPR(name, 0, "");
     PhysicalRules::iterator prit = physicalRules.find(&searchPR);
     if (prit == physicalRules.end()) {
diff --git a/chamsin/src/technology/ATechnology.h b/chamsin/src/technology/ATechnology.h
index 8242e7aa..b6b17172 100644
--- a/chamsin/src/technology/ATechnology.h
+++ b/chamsin/src/technology/ATechnology.h
@@ -38,21 +38,21 @@ class ATechnology : public PrivateProperty {
                 }
             };
 
-        typedef pair<Layer*, Layer*> LayerPair;
+        typedef pair<const Layer*, const Layer*> LayerPair;
 
         struct LayerPairCompare:
             public std::binary_function<const LayerPair&, const LayerPair&, bool> {
                 bool operator()(const LayerPair& lp1, const LayerPair& lp2) const {
-                    if (lp1->first < lp2->first) {
+                    if (lp1.first < lp2.first) {
                         return -1;
                     }
-                    if (lp1->first > lp2->first) {
+                    if (lp1.first > lp2.first) {
                         return 1;
                     }
-                    if (lp1->second < lp2->second) {
+                    if (lp1.second < lp2.second) {
                         return -1;
                     }
-                    if (lp1->second > lp2->second) {
+                    if (lp1.second > lp2.second) {
                         return 1;
                     }
                     return 0;
@@ -60,7 +60,7 @@ class ATechnology : public PrivateProperty {
             };
 
         typedef set<ATechnology::PhysicalRule*, PhysicalRuleNameCompare> PhysicalRules;
-        typedef map<Layer*, PhysicalRules> OneLayerPhysicalRules;
+        typedef map<const Layer*, PhysicalRules> OneLayerPhysicalRules;
         typedef map<LayerPair, PhysicalRules, LayerPairCompare> TwoLayersPhysicalRules;
 
         static ATechnology* create(Hurricane::Technology* technology);