diff --git a/MANIFEST.in b/MANIFEST.in
index a86fff7..a728a97 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,4 +2,5 @@ include README.md LICENSE
 include opfunu/cec/cec2005/support_data/*.txt
 include opfunu/cec/cec2008/support_data/*.txt
 include opfunu/cec/cec2010/support_data/*.txt
-include opfunu/cec/cec2014/support_data/*.txt
\ No newline at end of file
+include opfunu/cec/cec2014/support_data/*.txt
+include opfunu/cec/cec2015/support_data/*.txt
\ No newline at end of file
diff --git a/README.md b/README.md
index 9122e0d..b222820 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # Optimization Function in Numpy (OpFuNu)
-[![GitHub release](https://img.shields.io/badge/release-0.6.0-yellow.svg)]()
+[![GitHub release](https://img.shields.io/badge/release-0.6.1-yellow.svg)]()
 [![Wheel](https://img.shields.io/pypi/wheel/gensim.svg)](https://pypi.python.org/pypi/opfunu) 
 [![PyPI version](https://badge.fury.io/py/opfunu.svg)](https://badge.fury.io/py/opfunu)
 [![DOI version](https://zenodo.org/badge/DOI/10.5281/zenodo.3620960.svg)](https://badge.fury.io/py/opfunu)
diff --git a/docs/refs/unconstraint/niching/CEC2015 Niching Benchmarks.pdf b/docs/refs/unconstraint/niching/CEC2015 Niching Benchmarks.pdf
new file mode 100644
index 0000000..b98f2ad
Binary files /dev/null and b/docs/refs/unconstraint/niching/CEC2015 Niching Benchmarks.pdf differ
diff --git a/opfunu/cec/utils.py b/opfunu/cec/utils.py
new file mode 100644
index 0000000..6f42141
--- /dev/null
+++ b/opfunu/cec/utils.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python
+# ------------------------------------------------------------------------------------------------------%
+# Created by "Thieu Nguyen" at 19:26, 24/04/2020                                                        %
+#                                                                                                       %
+#       Email:      nguyenthieu2102@gmail.com                                                           %
+#       Homepage:   https://www.researchgate.net/profile/Thieu_Nguyen6                                  %
+#       Github:     https://github.com/thieunguyen5991                                                  %
+#-------------------------------------------------------------------------------------------------------%
+
+import pkg_resources
+from pandas import read_csv
+from numpy import sum, exp, cos, sin, sqrt, e, pi, abs, round
+
+class BasicFunction:
+    def __init__(self, name="cec2015"):
+        self.name = name
+        self.CURRENT_PATH = pkg_resources.resource_filename("opfunu", "cec/" + name + "/")
+        self.SUPPORT_PATH_DATA = pkg_resources.resource_filename("opfunu", "cec/" + name + "/support_data/")
+
+    def load_shift_data__(self, data_file=None):
+        data = read_csv(self.SUPPORT_PATH_DATA + data_file, delimiter='\s+', index_col=False, header=None)
+        return data.values.reshape((-1))
+
+    def load_matrix_data__(self, data_file=None):
+        data = read_csv(self.SUPPORT_PATH_DATA + data_file, delimiter='\s+', index_col=False, header=None)
+        return data.values
+
+    def ackley__(self, solution=None):
+        return -20 * exp(-0.2 * sqrt(sum(solution ** 2) / len(solution))) - exp(sum(cos(2 * pi * solution)) / len(solution)) + 20 + e
+
+    def bent_cigar__(self, solution=None):
+        return solution[0] ** 2 + 10 ** 6 * sum(solution[1:] ** 2)
+
+    def discus__(self, solution=None):
+        return 10 ** 6 * solution[0] ** 2 + sum(solution[1:] ** 2)
+
+    def weierstrass__(self, solution=None, a=0.5, b=3, k_max=20):
+        result = 0.0
+        for i in range(0, len(solution)):
+            t1 = sum([a ** k * cos(2 * pi * b ** k * (solution[i] + 0.5)) for k in range(0, k_max)])
+            t2 = len(solution) * sum([a ** k * cos(2 * pi * b ** k * 0.5) for k in range(0, k_max)])
+            result += t1 - t2
+        return result
+
+    def katsuura__(self, solution=None):
+        result = 1.0
+        for i in range(0, len(solution)):
+            t1 = sum([abs(2 ** j * solution[i] - round(2 ** j * solution[i])) / 2 ** j for j in range(1, 33)])
+            result *= (1 + (i + 1) * t1) ** (10.0 / len(solution) ** 1.2)
+        return (result - 1) * 10 / len(solution) ** 2
+
+    def happy_cat__(self, solution=None):
+        return (abs(sum(solution ** 2) - len(solution))) ** 0.25 + (0.5 * sum(solution ** 2) + sum(solution)) / len(solution) + 0.5
+
+    def hgbat__(self, solution=None):
+        return (abs(sum(solution ** 2) ** 2 - sum(solution) ** 2)) ** 0.5 + (0.5 * sum(solution ** 2) + sum(solution)) / len(solution) + 0.5
+
+    def rosenbrock__(self, solution=None):
+        result = 0.0
+        for i in range(len(solution) - 1):
+            result += 100 * (solution[i] ** 2 - solution[i + 1]) ** 2 + (solution[i] - 1) ** 2
+        return result
+
+    def rastrigin__(self, solution=None):
+        return sum(solution ** 2 - 10 * cos(2 * pi * solution) + 10)
+
+    def elliptic__(self, solution=None):
+        result = 0
+        for i in range(len(solution)):
+            result += (10 ** 6) ** (i / (len(solution) - 1)) * solution[i] ** 2
+        return result
+
+    def modified_schwefel__(self, solution=None):
+        z = solution + 4.209687462275036e+002
+        result = 418.9829 * len(solution)
+        for i in range(0, len(solution)):
+            if z[i] > 500:
+                result -= (500 - z[i] % 500) * sin(sqrt(abs(500 - z[i] % 500))) - (z[i] - 500) ** 2 / (10000 * len(solution))
+            elif z[i] < -500:
+                result -= (z[i] % 500 - 500) * sin(sqrt(abs(z[i] % 500 - 500))) - (z[i] + 500) ** 2 / (10000 * len(solution))
+            else:
+                result -= z[i] * sin(abs(z[i]) ** 0.5)
+        return result
+
+    def expanded_scaffer__(self, solution=None):
+        def __xy__(x, y):
+            return 0.5 + (sin(sqrt(x ** 2 + y ** 2)) ** 2 - 0.5) / (1 + 0.001 * (x ** 2 + y ** 2)) ** 2
+
+        result = __xy__(solution[-1], solution[0])
+        for i in range(0, len(solution) - 1):
+            result += __xy__(solution[i], solution[i + 1])
+        return result
+
+    def griewank__(self, solution=None):
+        result = sum(solution ** 2) / 4000
+        temp = 1.0
+        for i in range(len(solution)):
+            temp *= cos(solution[i] / sqrt(i + 1))
+        return result - temp + 1
+
+    def expanded_griewank__(self, solution=None):
+        def __f10__(x=None, y=None):
+            return 100 * (x ** 2 - y) ** 2 + (x - 1) ** 2
+
+        def __f11__(z=None):
+            return z ** 2 / 4000 - cos(z / sqrt(1)) + 1
+
+        result = __f11__(__f10__(solution[-1], solution[0]))
+        for i in range(0, len(solution) - 1):
+            result += __f11__(__f10__(solution[i], solution[i + 1]))
+        return result
diff --git a/setup.py b/setup.py
index 90bca46..f039eae 100644
--- a/setup.py
+++ b/setup.py
@@ -7,14 +7,14 @@ def readme():
 
 setup(
     name="opfunu",
-    version="0.6.0",
+    version="0.6.1",
     author="Thieu Nguyen",
     author_email="nguyenthieu2102@gmail.com",
-    description="A python (Numpy) package for Un-constrained Optimization Functions",
+    description="A framework of un-constrained Optimization Functions in Numpy (MEALPY) for global optimization problems",
     long_description=readme(),
     long_description_content_type="text/markdown",
     url="https://github.com/thieunguyen5991/opfunu",
-    download_url="https://github.com/thieunguyen5991/opfunu/archive/v0.6.0.zip",
+    download_url="https://github.com/thieunguyen5991/opfunu/archive/v0.6.1.zip",
     packages=find_packages(),
     include_package_data=True,
     license="MIT",