Table 4 Degree centrality analysis

Period 1		Period 2		Period 3		Period 4
Keyword	Degree centrality	Keyword	Degree centrality	Keyword	Degree centrality	Keyword	Degree centrality
Food culture	1	Food culture	1	Food culture	1	Food culture	1
Look	0.982456	Take picture	1	Look	1	Look	1
Take picture	0.964912	Look	1	Park	0.988764	Photograph	1
Photograph	0.964912	Eat	1	Buy	0.988764	Take picture	1
Eat	0.964912	Photograph	0.988372	Atmosphere	0.988764	Wear	1
Buy	0.947368	Atmosphere	0.988372	Eat	0.988764	Eat	1
Make	0.947368	Make	0.988372	Photograph	0.988764	Use	0.989247
Atmosphere	0.929825	Use	0.976744	Ride	0.977528	Buy	0.989247
Drink	0.912281	Buy	0.953488	Take picture	0.977528	Park	0.978495
Feel	0.824561	Meet	0.953488	Use	0.977528	Atmosphere	0.978495
Use	0.807018	Market	0.953488	Find	0.966292	Make	0.978495
Photo excursion	0.789474	Feel	0.953488	Meet	0.966292	Meet	0.978495
Ride	0.736842	Drink	0.94186	Drink	0.966292	Drink	0.978495
Find	0.736842	Browsing	0.94186	Feel	0.966292	Feel	0.978495
Props	0.719298	Find	0.906977	Flower	0.966292	Find	0.978495
Read	0.649123	Wear	0.906977	Browsing	0.966292	Walk	0.978495
Listen	0.649123	Ride	0.895349	Walk	0.966292	Photo excursion	0.967742
Chatting	0.631579	Happy	0.872093	Photo excursion	0.955056	Browsing	0.967742
Rest	0.614035	Gather	0.872093	Market	0.955056	Market	0.956989
Market	0.614035	Bake	0.872093	Wear	0.932584	Date	0.956989
Meet	0.596491	Props	0.860465	Read	0.932584	Flower	0.956989
Wander	0.596491	Walk	0.860465	Make	0.932584	Bake	0.956989
Drawing	0.596491	Play	0.848837	Sell	0.921348	Ride	0.946237
Purchase	0.596491	Draw	0.848837	Rest	0.921348	Rest	0.946237
Workroom	0.578947	Clothes	0.837209	Burn	0.910112	Listen	0.946237
Clothes	0.578947	Present	0.837209	Chatting	0.910112	Play	0.946237
Browsing	0.578947	Taste	0.837209	Tree	0.898876	Stroll	0.935484
Studio	0.578947	Sell	0.825581	Props	0.898876	Present	0.924731
Exhibition	0.561404	Flower	0.825581	Book	0.898876	Gather	0.924731
Present	0.561404	Listen	0.813953	Draw	0.898876	Happy	0.913978
Taste	0.561404	Book	0.802326	Clothes	0.887640	Clothes	0.913978
Draw	0.543860	Health	0.802326	Listen	0.887640	Get excited	0.913978
Bake	0.543860	Photo excursion	0.790698	Wander	0.887640	Chatting	0.913978
Nature	0.526316	Drawing	0.790698	Date	0.887640	Props	0.913978
Walk	0.526316	Shop	0.790698	Happy	0.876404	Wander	0.913978
Get drunk	0.508772	Chat	0.779070	Daily life	0.876404	Movie	0.903226
Book	0.508772	Chatting	0.744186	Stroll	0.876404	Pick	0.903226
Flower	0.508772	Music	0.732558	Hay	0.876404	Look around	0.903226
Wash	0.491228	Grab Food	0.720930	Purchase	0.876404	Tree	0.903226
Burn	0.473684	Bookstore	0.720930	Get excited	0.865169	Drawing	0.903226