src/main/kotlin/kr/co/vividnext/sodalive/v2/recommendation/domain/RecommendationScorePolicy.kt

@@ -28,6 +28,16 @@ class RecommendationScorePolicy {
         }
     }
 
+    fun calculateCommunityCreatorNewBoost(debutAt: LocalDateTime, now: LocalDateTime): Double {
+        val days = ChronoUnit.DAYS.between(debutAt.toLocalDate(), now.toLocalDate())
+        return when {
+            days <= RecommendationScoreSpec.NEW_BOOST_10_DAY_LIMIT -> RecommendationScoreSpec.COMMUNITY_NEW_BOOST_10_DAYS
+            days <= RecommendationScoreSpec.NEW_BOOST_20_DAY_LIMIT -> RecommendationScoreSpec.COMMUNITY_NEW_BOOST_20_DAYS
+            days <= RecommendationScoreSpec.NEW_BOOST_30_DAY_LIMIT -> RecommendationScoreSpec.COMMUNITY_NEW_BOOST_30_DAYS
+            else -> RecommendationScoreSpec.DEFAULT_NEW_BOOST
+        }
+    }
+
     fun calculateDebutCreatorScore(
         followIncrease: Long,
         contentActivityScore: Long,

src/main/kotlin/kr/co/vividnext/sodalive/v2/recommendation/domain/RecommendationScoreSpec.kt

@@ -18,7 +18,7 @@ object RecommendationScoreSpec {
     const val CHEER_DONATION_COUNT_WEIGHT = 0.1
 
     const val COMMUNITY_LIKE_WEIGHT = 0.5
-    const val COMMUNITY_COMMENT_WEIGHT = 0.5
+    const val COMMUNITY_COMMENT_WEIGHT = 0.4
     const val COMMUNITY_FOLLOWER_WEIGHT = 0.1
 
     const val NEW_BOOST_10_DAYS = 1.5
@@ -30,5 +30,8 @@ object RecommendationScoreSpec {
     const val CHEER_NEW_BOOST_10_DAYS = 1.15
     const val CHEER_NEW_BOOST_20_DAYS = 1.10
     const val CHEER_NEW_BOOST_30_DAYS = 1.05
+    const val COMMUNITY_NEW_BOOST_10_DAYS = 1.15
+    const val COMMUNITY_NEW_BOOST_20_DAYS = 1.10
+    const val COMMUNITY_NEW_BOOST_30_DAYS = 1.05
     const val DEFAULT_NEW_BOOST = 1.0
 }

src/main/kotlin/kr/co/vividnext/sodalive/v2/recommendation/domain/RecommendationSnapshotWindowPolicy.kt

@@ -28,6 +28,11 @@ class RecommendationSnapshotWindowPolicy {
         )
     }
 
+    fun previousKstSevenDayUtcWindow(nowUtc: LocalDateTime): RecommendationSnapshotWindow {
+        val dayWindow = previousKstDayUtcWindow(nowUtc)
+        return dayWindow.copy(startUtc = dayWindow.startUtc.minusDays(6))
+    }
+
     companion object {
         private val UTC_ZONE: ZoneId = ZoneId.of("UTC")
         private val KST_ZONE: ZoneId = ZoneId.of("Asia/Seoul")

src/test/kotlin/kr/co/vividnext/sodalive/v2/recommendation/domain/RecommendationScorePolicyTest.kt

@@ -115,17 +115,36 @@ class RecommendationScorePolicyTest {
     @DisplayName("인기 커뮤니티 점수는 좋아요 수, 댓글 수, 팔로우 수에 가중치를 적용한다")
     fun shouldCalculateCommunityScore() {
         assertEquals(0.5, RecommendationScoreSpec.COMMUNITY_LIKE_WEIGHT, 0.0001)
-        assertEquals(0.5, RecommendationScoreSpec.COMMUNITY_COMMENT_WEIGHT, 0.0001)
+        assertEquals(0.4, RecommendationScoreSpec.COMMUNITY_COMMENT_WEIGHT, 0.0001)
         assertEquals(0.1, RecommendationScoreSpec.COMMUNITY_FOLLOWER_WEIGHT, 0.0001)
 
-        val score = policy.calculateCommunityScore(
-            likeCount = 40,
-            commentCount = 20,
-            followerCount = 100,
-            newBoost = 1.2
-        )
+        assertEquals(0.0, policy.calculateCommunityScore(0, 0, 0, 1.0), 0.0001)
+        assertEquals(5.0, policy.calculateCommunityScore(10, 0, 0, 1.0), 0.0001)
+        assertEquals(4.0, policy.calculateCommunityScore(0, 10, 0, 1.0), 0.0001)
+        assertEquals(1.0, policy.calculateCommunityScore(0, 0, 10, 1.0), 0.0001)
+        assertEquals(38.0, policy.calculateCommunityScore(40, 20, 100, 1.0), 0.0001)
+        assertEquals(43.7, policy.calculateCommunityScore(40, 20, 100, 1.15), 0.0001)
+    }
 
-        assertEquals(48.0, score, 0.0001)
+    @Test
+    @DisplayName("인기 커뮤니티 신규 부스트는 데뷔일 기준 10일/20일/30일 구간을 적용한다")
+    fun shouldApplyCommunityCreatorNewBoostByDebutDays() {
+        val now = LocalDateTime.of(2026, 5, 30, 12, 0)
+
+        assertEquals(1.15, RecommendationScoreSpec.COMMUNITY_NEW_BOOST_10_DAYS, 0.0001)
+        assertEquals(1.10, RecommendationScoreSpec.COMMUNITY_NEW_BOOST_20_DAYS, 0.0001)
+        assertEquals(1.05, RecommendationScoreSpec.COMMUNITY_NEW_BOOST_30_DAYS, 0.0001)
+        assertEquals(1.15, policy.calculateCommunityCreatorNewBoost(now, now), 0.0001)
+        assertEquals(1.15, policy.calculateCommunityCreatorNewBoost(now.minusDays(10), now), 0.0001)
+        assertEquals(1.10, policy.calculateCommunityCreatorNewBoost(now.minusDays(11), now), 0.0001)
+        assertEquals(1.10, policy.calculateCommunityCreatorNewBoost(now.minusDays(20), now), 0.0001)
+        assertEquals(1.05, policy.calculateCommunityCreatorNewBoost(now.minusDays(21), now), 0.0001)
+        assertEquals(1.05, policy.calculateCommunityCreatorNewBoost(now.minusDays(30), now), 0.0001)
+        assertEquals(1.0, policy.calculateCommunityCreatorNewBoost(now.minusDays(31), now), 0.0001)
+
+        assertEquals(1.5, policy.calculateCreatorNewBoost(now.minusDays(10), now), 0.0001)
+        assertEquals(1.3, policy.calculateCreatorNewBoost(now.minusDays(20), now), 0.0001)
+        assertEquals(1.2, policy.calculateCreatorNewBoost(now.minusDays(30), now), 0.0001)
     }
 
     @Test

src/test/kotlin/kr/co/vividnext/sodalive/v2/recommendation/domain/RecommendationSnapshotWindowPolicyTest.kt

@@ -17,4 +17,14 @@ class RecommendationSnapshotWindowPolicyTest {
         assertEquals(LocalDateTime.of(2026, 7, 9, 15, 0, 0), window.endExclusiveUtc)
         assertEquals(LocalDateTime.of(2026, 7, 9, 14, 59, 59), window.snapshotAt)
     }
+
+    @Test
+    @DisplayName("KST 전날을 포함한 최근 7일을 UTC 조회 범위로 변환한다")
+    fun shouldConvertPreviousKstSevenDaysToUtcWindow() {
+        val window = policy.previousKstSevenDayUtcWindow(LocalDateTime.of(2026, 7, 10, 3, 0, 0))
+
+        assertEquals(LocalDateTime.of(2026, 7, 2, 15, 0, 0), window.startUtc)
+        assertEquals(LocalDateTime.of(2026, 7, 9, 15, 0, 0), window.endExclusiveUtc)
+        assertEquals(LocalDateTime.of(2026, 7, 9, 14, 59, 59), window.snapshotAt)
+    }
 }