[maven-release-plugin] prepare release v0.5.2-rc1
diff --git a/core/pom.xml b/core/pom.xml
index c1cea8e..b4271dd 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/dist/pom.xml b/dist/pom.xml
index f1df1d9..5d8f522 100644
--- a/dist/pom.xml
+++ b/dist/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/mixserv/pom.xml b/mixserv/pom.xml
index 30fbfb0..0e2fcc4 100644
--- a/mixserv/pom.xml
+++ b/mixserv/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/nlp/pom.xml b/nlp/pom.xml
index c0054fd..1626fcd 100644
--- a/nlp/pom.xml
+++ b/nlp/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/pom.xml b/pom.xml
index 5c2fb0d..c4739d1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -16,13 +16,12 @@
   specific language governing permissions and limitations
   under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
 	<groupId>org.apache.hivemall</groupId>
 	<artifactId>hivemall</artifactId>
-	<version>0.5.2-incubating-SNAPSHOT</version>
+	<version>0.5.2-incubating</version>
 
 	<parent>
 	  <groupId>org.apache</groupId>
@@ -51,7 +50,7 @@
 		<url>https://git-wip-us.apache.org/repos/asf/incubator-hivemall.git</url>
 		<connection>scm:git:https://git-wip-us.apache.org/repos/asf/incubator-hivemall.git</connection>
 		<developerConnection>scm:git:https://git-wip-us.apache.org/repos/asf/incubator-hivemall.git</developerConnection>
-		<tag>v0.5.0-rc1</tag>
+		<tag>v0.5.2-rc1</tag>
 	</scm>
 
 	<mailingLists>
diff --git a/spark/common/pom.xml b/spark/common/pom.xml
index eea931f..c2090c9 100644
--- a/spark/common/pom.xml
+++ b/spark/common/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall-spark</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spark/pom.xml b/spark/pom.xml
index ecc1608..8e3630d 100644
--- a/spark/pom.xml
+++ b/spark/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spark/spark-2.1/pom.xml b/spark/spark-2.1/pom.xml
index e6f0e6b..e03f4c0 100644
--- a/spark/spark-2.1/pom.xml
+++ b/spark/spark-2.1/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall-spark</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spark/spark-2.2/pom.xml b/spark/spark-2.2/pom.xml
index 1e23e49..c1f240c 100644
--- a/spark/spark-2.2/pom.xml
+++ b/spark/spark-2.2/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall-spark</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spark/spark-2.3/pom.xml b/spark/spark-2.3/pom.xml
index 658622c..7958451 100644
--- a/spark/spark-2.3/pom.xml
+++ b/spark/spark-2.3/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall-spark</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/tools/hivemall-docs/pom.xml b/tools/hivemall-docs/pom.xml
index d497cc6..41a22a9 100644
--- a/tools/hivemall-docs/pom.xml
+++ b/tools/hivemall-docs/pom.xml
@@ -16,15 +16,13 @@
   specific language governing permissions and limitations
   under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall-tools</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
@@ -136,7 +134,7 @@
 										</goals>
 									</pluginExecutionFilter>
 									<action>
-										<ignore></ignore>
+										<ignore />
 									</action>
 								</pluginExecution>
 							</pluginExecutions>
diff --git a/tools/pom.xml b/tools/pom.xml
index 52b08a8..aafefca 100644
--- a/tools/pom.xml
+++ b/tools/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/xgboost/pom.xml b/xgboost/pom.xml
index 7919c8c..db5310c 100644
--- a/xgboost/pom.xml
+++ b/xgboost/pom.xml
@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>org.apache.hivemall</groupId>
 		<artifactId>hivemall</artifactId>
-		<version>0.5.2-incubating-SNAPSHOT</version>
+		<version>0.5.2-incubating</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>