
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
In $\triangle ABC$, angle $B$ is acute. The sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. Given vectors $\overrightarrow{m}=(2\sin (A+C), \sqrt {3})$ and $\overrightarrow{n}=(\cos 2B,2\cos ^{2} \frac {B}{2}-1)$, and vectors $\overrightarrow{m}$ and $\overrightarrow{n}$ are collinear.

(1) Find the measure of angle $B$;

(2) If $b=1$, and $S_{\triangle ABC}= \frac { \sqrt {3}}{2}$, find the value of $a+c$.

Present the answer in LaTex format: \boxed{Your answer}
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