diff --git a/kernel/lcrconn/src/common.rs b/kernel/lcrconn/src/common.rs
index 795b237..38b7649 100644
--- a/kernel/lcrconn/src/common.rs
+++ b/kernel/lcrconn/src/common.rs
@@ -1,6 +1,41 @@
 use strum_macros::EnumIter;
 use thiserror::Error as TeError;
 
+// region: Sanitizer
+
+#[derive(Debug, TeError)]
+#[error("given floating value {0} is invalid")]
+pub struct FloatingPointError(f64);
+
+pub fn sanitize_floating_point(f: f64) -> Result<f64, FloatingPointError> {
+    if f.is_finite() {
+        Ok(f)
+    } else {
+        Err(FloatingPointError(f))
+    }
+}
+
+#[derive(Debug, TeError)]
+pub enum DeviceValueError {
+    #[error("{0}")]
+    BadFloatingPoint(#[from] FloatingPointError),
+    #[error("given device value {0} is out of range")]
+    OutOfRange(f64),
+}
+
+pub fn sanitize_device_value(f: f64) -> Result<f64, DeviceValueError> {
+    let f = sanitize_floating_point(f)?;
+    if f > 0f64 {
+        Ok(f)
+    } else {
+        Err(DeviceValueError::OutOfRange(f))
+    }
+}
+
+// endregion
+
+// region: Circuit Utilities
+
 /// The kind of device.
 #[derive(Debug, Clone, Copy)]
 pub enum DeviceKind {
@@ -35,82 +70,6 @@ impl JointKind {
     }
 }
 
-/// Error occurs when manipulating [SubCircuit].
-#[derive(Debug, TeError)]
-pub enum SubCircuitError {
-    #[error("given circuit device value {0} should greater than zero")]
-    BadDeviceValue(f64),
-    #[error("the previous computed circuit value {0} should greater than zero")]
-    BadPreviousValue(f64),
-    #[error("bad float point arithmetic")]
-    BadArithmetic,
-}
-
-/// The part of circuit composed of two devices and the joint kind.
-#[derive(Debug, Clone)]
-pub struct SubCircuit {
-    /// The value of the device.
-    device_value: f64,
-    /// The joint kind between this device and the next device.
-    joint_kind: JointKind,
-}
-
-impl SubCircuit {
-    /// Initialize subcircuit with given device value and joint kind.
-    ///
-    /// The input device value should greater than zero,
-    /// otherwise an error will return.
-    pub fn new(device_value: f64, joint_kind: JointKind) -> Result<Self, SubCircuitError> {
-        if device_value > 0f64 {
-            Ok(Self {
-                device_value,
-                joint_kind,
-            })
-        } else {
-            Err(SubCircuitError::BadDeviceValue(device_value))
-        }
-    }
-
-    /// Compute the joint value with given previous computed value and device kind.
-    ///
-    /// Parameter `value` should be the value computed from previous devices.
-    /// And it should greater than zero.
-    /// `device_kind` is the kind of the device.
-    pub fn compute(&self, value: f64, device_kind: DeviceKind) -> Result<f64, SubCircuitError> {
-        // Check the range of provided value for computing
-        if !(value > 0f64) {
-            return Err(SubCircuitError::BadPreviousValue(value));
-        }
-
-        // We perform series connect for: series resistor, series inductor and parallel capacitor.
-        // We perform parallel connect for: parallel resistor, parallel inductor and series capacitor.
-        let joint_kind = match device_kind {
-            DeviceKind::Capacitor => self.joint_kind.flip(),
-            _ => self.joint_kind,
-        };
-
-        let rv = match joint_kind {
-            JointKind::Series => self.device_value + value,
-            JointKind::Parallel => (self.device_value * value) / (self.device_value + value),
-        };
-        if rv.is_finite() {
-            Ok(rv)
-        } else {
-            Err(SubCircuitError::BadArithmetic)
-        }
-    }
-
-    /// Get the device value.
-    pub fn device_value(&self) -> f64 {
-        self.device_value
-    }
-
-    /// Get the joint kind.
-    pub fn joint_kind(&self) -> JointKind {
-        self.joint_kind
-    }
-}
-
 /// The scale of devices in the circuit.
 #[derive(Debug, Clone, Copy)]
 pub enum CircuitDeviceScale {
@@ -134,11 +93,84 @@ impl CircuitDeviceScale {
     }
 }
 
+// endregion
+
+// region: Circuit Stuff
+
+/// Error occurs when manipulating [SubCircuit].
+#[derive(Debug, TeError)]
+pub enum SubCircuitError {
+    #[error("invalid device value in circuit: {0}")]
+    BadDeviceValue(DeviceValueError),
+    #[error("bad previous computed circuit value: {0}")]
+    BadPreviousValue(DeviceValueError),
+    #[error("arithmetic error: {0}")]
+    BadArithmetic(FloatingPointError),
+}
+
+/// The part of circuit composed of two devices and the joint kind.
+#[derive(Debug, Clone)]
+pub struct SubCircuit {
+    /// The value of the device.
+    device_value: f64,
+    /// The joint kind between this device and the next device.
+    joint_kind: JointKind,
+}
+
+impl SubCircuit {
+    /// Initialize subcircuit with given device value and joint kind.
+    ///
+    /// The input device value should greater than zero,
+    /// otherwise an error will return.
+    pub fn new(device_value: f64, joint_kind: JointKind) -> Result<Self, SubCircuitError> {
+        let device_value = sanitize_device_value(device_value)
+            .map_err(|err| SubCircuitError::BadDeviceValue(err))?;
+        Ok(Self {
+            device_value,
+            joint_kind,
+        })
+    }
+
+    /// Compute the joint value with given previous computed value and device kind.
+    ///
+    /// Parameter `value` should be the value computed from previous devices.
+    /// And it should greater than zero.
+    /// `device_kind` is the kind of the device.
+    pub fn compute(&self, value: f64, device_kind: DeviceKind) -> Result<f64, SubCircuitError> {
+        // Check the range of provided value for computing
+        let value =
+            sanitize_device_value(value).map_err(|err| SubCircuitError::BadPreviousValue(err))?;
+
+        // We perform series connect for: series resistor, series inductor and parallel capacitor.
+        // We perform parallel connect for: parallel resistor, parallel inductor and series capacitor.
+        let joint_kind = match device_kind {
+            DeviceKind::Capacitor => self.joint_kind.flip(),
+            _ => self.joint_kind,
+        };
+
+        sanitize_floating_point(match joint_kind {
+            JointKind::Series => self.device_value + value,
+            JointKind::Parallel => (self.device_value * value) / (self.device_value + value),
+        })
+        .map_err(|err| SubCircuitError::BadArithmetic(err))
+    }
+
+    /// Get the device value.
+    pub fn device_value(&self) -> f64 {
+        self.device_value
+    }
+
+    /// Get the joint kind.
+    pub fn joint_kind(&self) -> JointKind {
+        self.joint_kind
+    }
+}
+
 /// Error occurs when manipulating [Circuit].
 #[derive(Debug, TeError)]
 pub enum CircuitError {
-    #[error("given circuit device value {0} should greater than zero")]
-    BadDeviceValue(f64),
+    #[error("invalid device value in circuit: {0}")]
+    BadDeviceValue(DeviceValueError),
     #[error("third device cannot exist without second device when building circuit")]
     BlankSecondSubCircuit,
     #[error("{0}")]
@@ -170,9 +202,8 @@ impl Circuit {
         third_device_subckt: Option<SubCircuit>,
     ) -> Result<Self, CircuitError> {
         // Check the value of first device
-        if !(first_device_value > 0f64) {
-            return Err(CircuitError::BadDeviceValue(first_device_value));
-        }
+        let first_device_value = sanitize_device_value(first_device_value)
+            .map_err(|err| CircuitError::BadDeviceValue(err))?;
         // Check impossible form
         if second_device_subckt.is_none() && third_device_subckt.is_some() {
             return Err(CircuitError::BlankSecondSubCircuit);
@@ -292,14 +323,14 @@ impl Circuit {
 /// Error occurs when manipulating [CircuitCalculator].
 #[derive(Debug, TeError)]
 pub enum CircuitCalculatorError {
-    #[error("given target value {0} should be greater than zero")]
-    BadTargetValue(f64),
+    #[error("invalid target value: {0}")]
+    BadTargetValue(DeviceValueError),
     #[error("{0}")]
     Circuit(#[from] CircuitError),
-    #[error("bad float point arithmetic")]
-    BadArithmetic,
-    #[error("provided value {0} reducing computation steps is invalid")]
-    BadReuseValue(f64),
+    #[error("arithmetic error: {0}")]
+    BadArithmetic(FloatingPointError),
+    #[error("bad provided value reducing computation steps: {0}")]
+    BadReuseValue(FloatingPointError),
 }
 
 /// The helper for circuit value computation.
@@ -314,14 +345,12 @@ pub struct CircuitCalculator {
 impl CircuitCalculator {
     /// Initialize this calculator with given device kind and target value.
     pub fn new(device_kind: DeviceKind, target_value: f64) -> Result<Self, CircuitCalculatorError> {
-        if target_value > 0f64 {
-            Ok(Self {
-                device_kind,
-                target_value,
-            })
-        } else {
-            Err(CircuitCalculatorError::BadTargetValue(target_value))
-        }
+        let target_value = sanitize_device_value(target_value)
+            .map_err(|err| CircuitCalculatorError::BadTargetValue(err))?;
+        Ok(Self {
+            device_kind,
+            target_value,
+        })
     }
 
     /// The value of this circuit.
@@ -343,22 +372,13 @@ impl CircuitCalculator {
         value: Option<f64>,
     ) -> Result<f64, CircuitCalculatorError> {
         let value = match value {
-            Some(v) => {
-                if v.is_finite() {
-                    v
-                } else {
-                    return Err(CircuitCalculatorError::BadReuseValue(v));
-                }
-            }
+            Some(v) => sanitize_floating_point(v)
+                .map_err(|err| CircuitCalculatorError::BadReuseValue(err))?,
             None => self.value(circuit)?,
         };
 
-        let rv = value - self.target_value;
-        if rv.is_finite() {
-            Ok(rv)
-        } else {
-            Err(CircuitCalculatorError::BadArithmetic)
-        }
+        sanitize_floating_point(value - self.target_value)
+            .map_err(|err| CircuitCalculatorError::BadArithmetic(err))
     }
 
     /// The unsigned difference between the target value and the value of this circuit.
@@ -376,22 +396,13 @@ impl CircuitCalculator {
         difference: Option<f64>,
     ) -> Result<f64, CircuitCalculatorError> {
         let diff = match difference {
-            Some(d) => {
-                if d.is_finite() {
-                    d
-                } else {
-                    return Err(CircuitCalculatorError::BadReuseValue(d));
-                }
-            }
+            Some(d) => sanitize_floating_point(d)
+                .map_err(|err| CircuitCalculatorError::BadReuseValue(err))?,
             None => self.difference(circuit, value)?,
         };
 
-        let rv = diff.abs();
-        if rv.is_finite() {
-            Ok(rv)
-        } else {
-            Err(CircuitCalculatorError::BadArithmetic)
-        }
+        sanitize_floating_point(diff.abs())
+            .map_err(|err| CircuitCalculatorError::BadArithmetic(err))
     }
 
     /// The signed relative difference between the target value and the value of this circuit.
@@ -412,22 +423,13 @@ impl CircuitCalculator {
         difference: Option<f64>,
     ) -> Result<f64, CircuitCalculatorError> {
         let diff = match difference {
-            Some(d) => {
-                if d.is_finite() {
-                    d
-                } else {
-                    return Err(CircuitCalculatorError::BadReuseValue(d));
-                }
-            }
+            Some(d) => sanitize_floating_point(d)
+                .map_err(|err| CircuitCalculatorError::BadReuseValue(err))?,
             None => self.difference(circuit, value)?,
         };
 
-        let rv = diff / self.target_value;
-        if rv.is_finite() {
-            Ok(rv)
-        } else {
-            Err(CircuitCalculatorError::BadArithmetic)
-        }
+        sanitize_floating_point(diff / self.target_value)
+            .map_err(|err| CircuitCalculatorError::BadArithmetic(err))
     }
 
     /// The unsigned relative difference between the target value and the value of this circuit.
@@ -450,21 +452,14 @@ impl CircuitCalculator {
         relative_difference: Option<f64>,
     ) -> Result<f64, CircuitCalculatorError> {
         let rel_diff = match relative_difference {
-            Some(rd) => {
-                if rd.is_finite() {
-                    rd
-                } else {
-                    return Err(CircuitCalculatorError::BadReuseValue(rd));
-                }
-            }
+            Some(rd) => sanitize_floating_point(rd)
+                .map_err(|err| CircuitCalculatorError::BadReuseValue(err))?,
             None => self.relative_difference(circuit, value, difference)?,
         };
 
-        let rv = rel_diff.abs();
-        if rv.is_finite() {
-            Ok(rv)
-        } else {
-            Err(CircuitCalculatorError::BadArithmetic)
-        }
+        sanitize_floating_point(rel_diff.abs())
+            .map_err(|err| CircuitCalculatorError::BadArithmetic(err))
     }
 }
+
+// endregion
diff --git a/kernel/lcrconn/src/dataset.rs b/kernel/lcrconn/src/dataset.rs
index 0dd7c5e..fefd42d 100644
--- a/kernel/lcrconn/src/dataset.rs
+++ b/kernel/lcrconn/src/dataset.rs
@@ -1,7 +1,12 @@
+use thiserror::Error as TeError;
 use std::collections::HashSet;
 use std::path::Path;
 
-use crate::common::LcrConnError;
+/// Error occurs when building dataset.
+#[derive(Debug, TeError)]
+pub enum DatasetError {
+
+}
 
 /// An item in the dataset.
 #[derive(Clone, Debug)]
@@ -17,14 +22,14 @@ impl DatasetItem {
     ///
     /// # Errors
     ///
-    /// Returns [`LcrConnError::InvalidDatasetValue`] if the value is not greater than 0.
-    /// Returns [`LcrConnError::EmptyDatasetItem`] if the string value is empty.
-    pub fn new(value: f64, str_value: String) -> Result<Self, LcrConnError> {
+    /// Returns [`DatasetError::InvalidDatasetValue`] if the value is not greater than 0.
+    /// Returns [`DatasetError::EmptyDatasetItem`] if the string value is empty.
+    pub fn new(value: f64, str_value: String) -> Result<Self, DatasetError> {
         if value <= 0.0 {
-            return Err(LcrConnError::InvalidDatasetValue(value));
+            return Err(DatasetError::InvalidDatasetValue(value));
         }
         if str_value.is_empty() {
-            return Err(LcrConnError::EmptyDatasetItem);
+            return Err(DatasetError::EmptyDatasetItem);
         }
         Ok(Self { value, str_value })
     }
@@ -46,10 +51,10 @@ impl Dataset {
     ///
     /// # Errors
     ///
-    /// Returns [`LcrConnError::DuplicateDatasetItem`] if duplicate values are found.
-    /// Returns [`LcrConnError::EmptyDataset`] if the iterable produces no items.
-    /// Returns [`LcrConnError::InvalidHumanReadableValue`] if a value cannot be parsed.
-    pub fn from_iterable<I, S>(str_values: I) -> Result<Self, LcrConnError>
+    /// Returns [`DatasetError::DuplicateDatasetItem`] if duplicate values are found.
+    /// Returns [`DatasetError::EmptyDataset`] if the iterable produces no items.
+    /// Returns [`DatasetError::InvalidHumanReadableValue`] if a value cannot be parsed.
+    pub fn from_iterable<I, S>(str_values: I) -> Result<Self, DatasetError>
     where
         I: IntoIterator<Item = S>,
         S: Into<String>,
@@ -64,7 +69,7 @@ impl Dataset {
             let value = from_human_readable_value(&str_value)?;
             // Check and update set
             if !seen.insert(value) {
-                return Err(LcrConnError::DuplicateDatasetItem(str_value));
+                return Err(DatasetError::DuplicateDatasetItem(str_value));
             }
             // Add into result
             items.push(DatasetItem::new(value, str_value)?);
@@ -72,7 +77,7 @@ impl Dataset {
 
         // Check empty case
         if items.is_empty() {
-            return Err(LcrConnError::EmptyDataset);
+            return Err(DatasetError::EmptyDataset);
         }
 
         // Ok, assign it
@@ -86,7 +91,7 @@ impl Dataset {
     /// # Errors
     ///
     /// See [`Dataset::from_iterable`].
-    pub fn from_text(text: &str) -> Result<Self, LcrConnError> {
+    pub fn from_text(text: &str) -> Result<Self, DatasetError> {
         let lines: Vec<String> = text
             .lines()
             .map(|line| line.trim().to_string())
@@ -99,9 +104,9 @@ impl Dataset {
     ///
     /// # Errors
     ///
-    /// Returns [`LcrConnError::Io`] if the file cannot be read.
+    /// Returns [`DatasetError::Io`] if the file cannot be read.
     /// See [`Dataset::from_iterable`] for other errors.
-    pub fn from_file(path: impl AsRef<Path>) -> Result<Self, LcrConnError> {
+    pub fn from_file(path: impl AsRef<Path>) -> Result<Self, DatasetError> {
         let text = std::fs::read_to_string(path)?;
         Self::from_text(&text)
     }
@@ -111,7 +116,7 @@ impl Dataset {
     /// # Errors
     ///
     /// See [`Dataset::from_iterable`].
-    pub fn resistor_preset() -> Result<Self, LcrConnError> {
+    pub fn resistor_preset() -> Result<Self, DatasetError> {
         Self::from_iterable([
             "100", "220", "270", "390", "470", "680", "1k", "1.2k", "1.5k", "2.2k", "3.3k",
             "4.7k", "6.8k", "10k", "47k", "100k", "1M",
@@ -123,7 +128,7 @@ impl Dataset {
     /// # Errors
     ///
     /// See [`Dataset::from_iterable`].
-    pub fn capacitor_preset() -> Result<Self, LcrConnError> {
+    pub fn capacitor_preset() -> Result<Self, DatasetError> {
         Self::from_iterable([
             "10p", "22p", "33p", "47p", "68p", "100p", "150p", "220p", "330p", "470p", "560p",
             "1u", "2.2u", "3.3u", "4.7u", "10u", "22u", "47u", "100u", "220u", "470u",
@@ -135,7 +140,7 @@ impl Dataset {
     /// # Errors
     ///
     /// See [`Dataset::from_iterable`].
-    pub fn inductor_preset() -> Result<Self, LcrConnError> {
+    pub fn inductor_preset() -> Result<Self, DatasetError> {
         Self::from_iterable([
             "0.1u", "0.15u", "0.47u", "0.68u", "1u", "1.5u", "2.2u", "3.3u", "4.7u", "6.8u",
             "8.2u", "10u", "15u", "22u", "33u", "47u", "68u", "100u",
@@ -155,8 +160,8 @@ impl Dataset {
     ///
     /// # Errors
     ///
-    /// Returns [`LcrConnError::Io`] if the file cannot be written.
-    pub fn save_file(&self, path: impl AsRef<Path>) -> Result<(), LcrConnError> {
+    /// Returns [`DatasetError::Io`] if the file cannot be written.
+    pub fn save_file(&self, path: impl AsRef<Path>) -> Result<(), DatasetError> {
         std::fs::write(path, self.save_text())?;
         Ok(())
     }
@@ -206,7 +211,7 @@ impl DatasetCollection {
         resistor: I1,
         capacitor: I2,
         inductor: I3,
-    ) -> Result<Self, LcrConnError>
+    ) -> Result<Self, DatasetError>
     where
         I1: IntoIterator<Item = S1>,
         S1: Into<String>,
@@ -233,7 +238,7 @@ impl DatasetCollection {
     /// # Errors
     ///
     /// See [`Dataset::from_text`].
-    pub fn from_text(resistor: &str, capacitor: &str, inductor: &str) -> Result<Self, LcrConnError> {
+    pub fn from_text(resistor: &str, capacitor: &str, inductor: &str) -> Result<Self, DatasetError> {
         Ok(Self {
             resistor: Dataset::from_text(resistor)?,
             capacitor: Dataset::from_text(capacitor)?,
@@ -256,7 +261,7 @@ impl DatasetCollection {
         resistor: impl AsRef<Path>,
         capacitor: impl AsRef<Path>,
         inductor: impl AsRef<Path>,
-    ) -> Result<Self, LcrConnError> {
+    ) -> Result<Self, DatasetError> {
         Ok(Self {
             resistor: Dataset::from_file(resistor)?,
             capacitor: Dataset::from_file(capacitor)?,
@@ -269,7 +274,7 @@ impl DatasetCollection {
     /// # Errors
     ///
     /// See [`Dataset::from_iterable`].
-    pub fn devices_preset() -> Result<Self, LcrConnError> {
+    pub fn devices_preset() -> Result<Self, DatasetError> {
         Ok(Self {
             resistor: Dataset::resistor_preset()?,
             capacitor: Dataset::capacitor_preset()?,
@@ -300,13 +305,13 @@ impl DatasetCollection {
     ///
     /// # Errors
     ///
-    /// Returns [`LcrConnError::Io`] if any file cannot be written.
+    /// Returns [`DatasetError::Io`] if any file cannot be written.
     pub fn save_file(
         &self,
         resistor: impl AsRef<Path>,
         capacitor: impl AsRef<Path>,
         inductor: impl AsRef<Path>,
-    ) -> Result<(), LcrConnError> {
+    ) -> Result<(), DatasetError> {
         self.resistor.save_file(resistor)?;
         self.capacitor.save_file(capacitor)?;
         self.inductor.save_file(inductor)?;
@@ -329,6 +334,11 @@ impl DatasetCollection {
     }
 }
 
+#[derive(Debug, TeError)]
+pub enum ParseHumanReadableValueError {
+
+}
+
 /// Convert human readable value to float.
 ///
 /// # Arguments
@@ -341,8 +351,8 @@ impl DatasetCollection {
 ///
 /// # Errors
 ///
-/// Returns [`LcrConnError::InvalidHumanReadableValue`] if the input string is not a valid number.
-pub fn from_human_readable_value(strl: &str) -> Result<f64, LcrConnError> {
+/// Returns [`DatasetError::InvalidHumanReadableValue`] if the input string is not a valid number.
+pub fn from_human_readable_value(strl: &str) -> Result<f64, ParseHumanReadableValueError> {
     let strl = strl.trim();
 
     let (num_part, multiplier) = if let Some(stripped) = strl.strip_suffix('n') {
@@ -366,7 +376,7 @@ pub fn from_human_readable_value(strl: &str) -> Result<f64, LcrConnError> {
     num_part
         .parse::<f64>()
         .map(|v| v * multiplier)
-        .map_err(|_| LcrConnError::InvalidHumanReadableValue(strl.to_string()))
+        .map_err(|_| DatasetError::InvalidHumanReadableValue(strl.to_string()))
 }
 
 /// The unit scale for human readable value.