Close of an Academic Conference

Yesterday, an academic conference that was held in Nagoya city was over.

I am very pleased because student's study presentation that contains my name as a co-author earned an encouragement award.

After that, I went sightseeing with students, and stayed overnight at my home, then returned back to Tokyo.

Since today was Sunday, I visited some sightseeing spots in Shizuoka prefecture on my way back from Nagoya to Tokyo.

However, tomorrow is a national holiday, so today was the middle day of three-day weekends.

It is said that sightseeing spots will be the most crowded in the day.

As expected, since I was stuck in major traffic jam, I was very tired.

学会終了

昨日、名古屋で行われていた学会が終了しました。

共著者に名前を載せてもらっている研究発表が奨励賞を受賞したため、とても嬉しく思っています。

その後は、学生達と名古屋を観光し、一泊してから東京に戻りました。

今日は休日なので、名古屋から東京に戻る途中、静岡県の観光地を幾つか見て回りました。

しかし、明日が祝日であるため、今日は三連休の中日でした。

観光地は、中日が最も混むと言われています。

案の定渋滞に巻き込まれて、とても大変でした。

• Yesterday, an academic conference that was held in Nagoya city was over.
• Yesterday, an academic conference that was held in Nagoya city was over.

• I am very pleased because student's study presentation that contains my name as a co-author earned an encouragement award.
• I am very pleased because a student's study presentation that had my name as a co-author earned an encouragement award.

• After that, I went sightseeing with students, and stayed overnight at my home, then returned back to Tokyo.
• After that, I went sightseeing with students, and they stayed overnight at my home, then returned back to Tokyo.

• However, tomorrow is a national holiday, so today was the middle day of three-day weekends.
• However, tomorrow is a national holiday, so today was the second day of a three-day weekends.

• Close of an Academic Conference
• This sentence is perfect! No correction needed!

• Yesterday, an academic conference that was held in Nagoya city was over.
• Yesterday, an academic conference that was held in Nagoya city is was over.

  It didn't suddenly stop being over so you have to put it in present tense.

• I am very pleased because student's study presentation that contains my name as a co-author earned an encouragement award.
• I am very pleased because the student's study presentation that contains my name as a co-author earned an encouragement award.

  I think "the" would be better than "a" because you're talking about a specific presentation.

• After that, I went sightseeing with students, and stayed overnight at my home, then returned back to Tokyo.
• After that, I went sightseeing with the students, and stayed overnight at my home, and then returned back to Tokyo.

• Since today was Sunday, I visited some sightseeing spots in Shizuoka prefecture on my way back from Nagoya to Tokyo.
• Since today was Sunday, I visited some sightseeing spots in Shizuoka prefecture on my way back from Nagoya to Tokyo.

  (in blue)
  This is worded a bit odd. Using "today" means that you have to use "is," but since you stated something in the past, you have to use past tense. Also, it doesn't make sense to use "since" here. It's not immediately noticeable how it being Sunday causes you to visit some places.

• It is said that sightseeing spots will be the most crowded in the day.
• This sentence is perfect! No correction needed!

• As expected, since I was stuck in major traffic jam, I was very tired.
• This sentence is perfect! No correction needed!