diff --git a/pom.xml b/pom.xml
index 08c94e9..d165638 100644
--- a/pom.xml
+++ b/pom.xml
@@ -17,6 +17,20 @@
             <groupId>org.apache.jena</groupId>
             <artifactId>jena-tdb</artifactId>
             <version>0.9.3</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>log4j</groupId>
+                    <artifactId>log4j</artifactId>
+                </exclusion>
+                <exclusion>
+                    <artifactId>slf4j-api</artifactId>
+                    <groupId>org.slf4j</groupId>
+                </exclusion>
+                <exclusion>
+                    <artifactId>slf4j-log4j12</artifactId>
+                    <groupId>org.slf4j</groupId>
+                </exclusion>
+            </exclusions>
         </dependency>
         <dependency>
             <groupId>com.sleepycat</groupId>
@@ -27,6 +41,16 @@
             <groupId>com.espertech</groupId>
             <artifactId>esper</artifactId>
             <version>4.2.0</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>log4j</groupId>
+                    <artifactId>log4j</artifactId>
+                </exclusion>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
         </dependency>
         <dependency>
             <groupId>junit</groupId>
@@ -40,5 +64,15 @@
             <version>1.6.0</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>log4j-over-slf4j</artifactId>
+            <version>1.7.7</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>jcl-over-slf4j</artifactId>
+            <version>1.7.7</version>
+        </dependency>
     </dependencies>
 </project>
\ No newline at end of file
diff --git a/src/main/java/org/deri/cqels/engine/ExecContext.java b/src/main/java/org/deri/cqels/engine/ExecContext.java
index 0f9ebe9..1c435e3 100644
--- a/src/main/java/org/deri/cqels/engine/ExecContext.java
+++ b/src/main/java/org/deri/cqels/engine/ExecContext.java
@@ -60,7 +60,7 @@ public ExecContext(String path, boolean cleanDataset) {
 		//combine cache and disk-based dictionary
 		this.dictionary = new NodeTableNative(IndexBuilder.mem().newIndex(FileSet.mem(), 
 											  		SystemTDB.nodeRecordFactory), 
-											  FileFactory.createObjectFileMem(path));
+											  FileFactory.createObjectFileDisk(path + "/dict"));
 		setEngine(new CQELSEngine(this));
 		createCache(path + "/cache");
 		if (cleanDataset) {
diff --git a/src/main/resources/log4j.properties b/src/main/resources/log4j.properties
deleted file mode 100644
index e4fcb01..0000000
--- a/src/main/resources/log4j.properties
+++ /dev/null
@@ -1,9 +0,0 @@
-# Set root logger level to DEBUG and its only appender to A1.
-log4j.rootLogger=DEBUG, A1
-
-# A1 is set to be a ConsoleAppender.
-log4j.appender.A1=org.apache.log4j.ConsoleAppender
-
-# A1 uses PatternLayout.
-log4j.appender.A1.layout=org.apache.log4j.PatternLayout
-log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
\ No newline at end of file