Question: Walkin' is the debut mini-album by which South Korean singer-songwriter and record producer?

Context articles: List of songs written by Kim Jong-hyun
Love Style
Cross Gene
Hi! Pristin
Bad Girl (Beast song)
Bluetory
Suran (singer)
Walkin' (EP)
Growing Up (IU album)
Narsha (album)

Kim Jong-hyun (most often credited as Jonghyun), is a South Korean singer-songwriter and producer.
 He began his musical career in 2008 as a member of the group Shinee and later formed the ballad group S.M.
 The Ballad.
 Jonghyun debuted as a composer happened to write Korean lyrics for the Shinees promotional single "Juliette", which was featured in the mini-album "Romeo", released in May 2009.
 Participate in the writing of three songs on Shinee's second Korean studio album, "Lucifer", the first, "Up & Down", was co-written with Misfit with the rap being written by Minho, the second, "Obsession", was completely written by Jonghyun with Minho once again working on his own rap, and the third "Shout Out" co-written by all members of Shinee, JQ and Misfit.
 In 2012, Jonghyun co-wrote the lyrics to the song with "Alarm Clock" with Minho, a song about wishing to wake up from the nightmare of a past break up, and wrote the lyrics to "Honesty" which was described as a song written for the fans who had stayed by their side with unchanging love until that point.
 Both songs were featured on the mini album, "Sherlock".
Love Style is the debut mini-album by South Korean boy band Boyfriend.
 The mini-album was released digitally on June 13, 2012.
 Followed by the release of the physical album on June 14, 2012.
Cross Gene (Korean: 크로스진; stylized as CROSS GENE) is a five-member boy group based in South Korea.
 Signed under Amuse Korea, the group consists of South Korean members: Shin, Sangmin, Yongseok and Seyoung and Japanese member Takuya.
 They released their debut mini-album "Timeless: Begins" in 2012, which peaked at #8 on the Gaon weekly album chart.
Hi!
 Pristin (stylized as HI!
 PRISTIN) is the debut mini-album by South Korean girl group Pristin.
 It was released on March 21, 2017, by Pledis Entertainment, and distributed by LOEN Entertainment.
 The EP consists of six songs, including the singles "Wee Woo" and "Black Widow".
 In order to promote the album, the group performed on several Korean music shows.
"Bad Girl" is the debut single South Korean boy group Beast, coming from their debut mini-album "Beast is the B2ST" which was released in South Korea on October 14, 2009.
Bluetory is the debut mini-album by South Korean pop-rock idol band CNBLUE.
 It was released on January 14, 2010, under FNC Music and distributed by Mnet Media.
 After being signed to the record label, the quartet was sent to Japan, where it independently released two mini-albums.
 While working with the band, frontman Jung Yong-hwa was cast in the television drama "You're Beautiful" (2009), where he first garnered recognition.
Shin Su-ran (Hangul: 신수란), also known by her stage names Elena (Hangul: 엘에나) and Baily Shoo (Hangul: 베일리 슈), and better known by the mononym Suran (Hangul: 수란), is a South Korean singer-songwriter and record producer.
 She debuted as part of the duo, Lodia, on July 9, 2014, with the single "I Got A Feeling".
 In 2017, she has also appeared on MBC's "King of Mask Singer" (episodes 93–94) as a contestant named "Skip to the End, Hello".
Walkin' is the debut mini-album by South Korean singer Suran.
 It was released on June 2, 2017, by Million Market and distribuited by LOEN Entertainment.
 It consists of five songs, including "Wine" featuring rapper Changmo, previously released as a digital single, and the title track "1+1=0" featuring singer Dean.
Growing Up is the first Korean-language studio album by South Korean singer-songwriter and actress IU.
 It was released on April 23, 2009, as a follow-up to her 2008 debut mini-album "Lost and Found".
 Two of the album's 16 tracks, "Boo" and "You Know (있잖아) (Rock Ver.)"
, were released as singles.
Narsha (stylized as NARSHA) is the eponymous debut mini-album by South Korean recording artist and actress Narsha, a member from girl group Brown Eyed Girls.
 Lee Min-soo, her group's long-time producer served as the album's executive producer.
 Featuring a dark and edgy sound, it was released on July 8, 2010 and distributed by Nega Network.
 The EP features seven tracks in total, including one preview and one instrumental version of the album's title track.