diff --git a/docs/installation.md b/docs/installation.md
index 7c4cf0e8..be872cb5 100644
--- a/docs/installation.md
+++ b/docs/installation.md
@@ -43,7 +43,7 @@
 3. Run `docker-compose up` to build and launch the memory-scope cli interface.
 
 
-## III. Install from PyPI [Linux]
+## III. Install from PyPI
 1. Install from PyPI
 
 ```bash
@@ -90,7 +90,7 @@ The docker method is recommended:
             --enable_ranker=False
     ```
 
-## IV. Install from source [Linux only]
+## IV. Install from source
 
 1. Clone the repository and edit settings
     ```bash
diff --git a/docs/installation_zh.md b/docs/installation_zh.md
index eedb1018..c58c67a7 100644
--- a/docs/installation_zh.md
+++ b/docs/installation_zh.md
@@ -41,7 +41,7 @@
 3. 运行 `docker-compose up` 命令来构建并启动 MemoryScope CLI 界面。
 
 
-## 三、通过 PYPI 安装 [仅限 Linux]
+## 三、通过 PYPI 安装
 
 1. 从 PyPI 安装：
     ```bash
@@ -89,7 +89,7 @@
     ```
 
 
-## 四、从源码安装 [仅限 Linux]
+## 四、从源码安装
 
 1. 克隆仓库并编辑设置
     ```bash
diff --git a/examples/api/simple_usages_cn.ipynb b/examples/api/simple_usages_cn.ipynb
index 79ef7580..f4c0db3a 100644
--- a/examples/api/simple_usages_cn.ipynb
+++ b/examples/api/simple_usages_cn.ipynb
@@ -7,7 +7,7 @@
     "# chat 和 service 接口的示例用法\n",
     "这个笔记本展示了 MemoryScope 的 **chat** 和 **service** 接口的简单用法，以及它的主要功能。\n",
     "\n",
-    "在运行这个笔记本之前，请先按照 Readme 中的 **Installation** 指南进行安装，并启动 Docker 镜像。\n"
+    "在运行这个笔记本之前，请先按照 Readme 中的 [**Installation**](../../docs/installation_zh.md#三通过-pypi-安装) 指南进行安装，并启动 Docker 镜像。\n"
    ]
   },
   {
diff --git a/examples/api/simple_usages_en.ipynb b/examples/api/simple_usages_en.ipynb
index 0f7b0292..7e878ca1 100644
--- a/examples/api/simple_usages_en.ipynb
+++ b/examples/api/simple_usages_en.ipynb
@@ -7,7 +7,7 @@
     "# Example usages of **chat** and **service** interfaces\n",
     "This notebook shows simple usages of MemoryScope's **chat** and **service** interfaces, along with its main features.\n",
     "\n",
-    "Before running this notebook, follow the **Installation** guidelines in Readme, and start the Docker image first."
+    "Before running this notebook, follow the [**Installation**](../../docs/installation.md#iii-install-from-pypi) guidelines in Readme, and start the Docker image first."
    ]
   },
   {
diff --git a/memoryscope/core/operation/backend_operation.py b/memoryscope/core/operation/backend_operation.py
index 94f72b58..3d7f8514 100644
--- a/memoryscope/core/operation/backend_operation.py
+++ b/memoryscope/core/operation/backend_operation.py
@@ -1,4 +1,5 @@
 import time
+import threading
 
 from memoryscope.core.operation.base_operation import OPERATION_TYPE
 from memoryscope.core.operation.frontend_operation import FrontendOperation
@@ -10,6 +11,7 @@ class BackendOperation(FrontendOperation):
     It manages operation status, loop control, and integrates with a global context for thread management.
     """
     operation_type: OPERATION_TYPE = "backend"
+    operation_lock: threading.Lock = threading.Lock()
 
     def __init__(self, interval_time: int, **kwargs):
         super().__init__(**kwargs)
@@ -52,7 +54,8 @@ class BackendOperation(FrontendOperation):
 
                 for target_name in self.target_names:
                     try:
-                        self.run_operation(target_name=target_name, **kwargs)
+                        with BackendOperation.operation_lock:
+                            self.run_operation(target_name=target_name, **kwargs)
                     except Exception as e:
                         self.logger.exception(f"op_name={self.name} target_name={target_name} encounter exception. "
                                               f"args={e.args}")
diff --git a/memoryscope/core/utils/tool_functions.py b/memoryscope/core/utils/tool_functions.py
index d0d02d7a..9e4694ba 100644
--- a/memoryscope/core/utils/tool_functions.py
+++ b/memoryscope/core/utils/tool_functions.py
@@ -197,3 +197,24 @@ def cosine_similarity(query: List[float], documents: List[List[float]]):
 
     cosine_similarities = dot_product / (query_norm * documents_norm)
     return cosine_similarities.tolist()
+
+
+def cosine_similarity_matrix(query: List[List[float]]):
+    query = np.array(query)
+
+    documents_norm = np.linalg.norm(query, axis=1)
+    if np.any(documents_norm == 0):
+        raise ValueError("One of the document vectors has zero norm, which will result in a division by zero")
+    
+    n_query = query.shape[0]
+    query_expanded = np.expand_dims(query, axis=0)
+    query_triplicated = np.repeat(query_expanded, repeats=n_query, axis=0)
+    query_transpose = query_triplicated.swapaxes(0, 1)
+
+    q = np.expand_dims(documents_norm, axis=0)
+    norm_dot = q.transpose() * q
+    dot_product = (query_triplicated*query_transpose).sum(-1) / norm_dot
+
+    return dot_product
+
+