厳重になる、厳しくするなどの意味として"heightened"と"tightened"の両方を見聞きします。
heightened (heighten+ed)「（程度を）高くする」
tightenedは (tighten+ed)「しっかりと締める、（政策を）厳しくする、強化される」
It seems like security at Narita Airport was recently tightened.
「成田空港の警戒が最近厳しくなったような気がする。」
There has been a security clampdown at the airport
The airport is on a high security alert
To tighten up on something = this means to become stricter in something.
"The manager has really tightened up on players arriving late. They get fined now."
A high security alert means that for some reason there is now increased security.
A "clampdown" means stricter or stronger application of something in a particular scenario.
To tighten up on something = 何かに対して厳しくする
例："The manager has really tightened up on players arriving late. They get fined now."
マネージャが遅刻する選手に厳しくなって、罰金が支払わされている。
A high security alert とは、何かしらの理由でセキュリティレべルがあがっていることを言います。
A "clampdown"とは、特定の状況下で取り締まりを厳しくすることを言います。
Many airports have increased its security measures in order to protect their country and citizens from terrorism.
You can express this in a number of ways.
Here are two suggestions.
1. The airport has heightened its security.
The verb 'heightened" in this sentence means to increase or raise.
2. The airport has beefed up its security.
The expression "beefed up" means to increase or to go up;
Example:
The hotel plans to beef up its marketing effort.
多くの空港で、テロから国と市民を守るためにセキュリティを強化しています。
このことをいろんな言い方で表すことができます。
２つご提案します。
1. The airport has heightened its security.
heightened という動詞は、この場合増加させる、上げる、という意味です。
2. The airport has beefed up its security.
beefed up という表現は、増加させる、強化する、という意味です。
例：
The hotel plans to beef up its marketing effort.
（そのホテルはマーケティング対策を強化する予定だ。）
Airport management has implemented stricter security measures than before.
Airport security has been beefed up recently.
Airport security has been strengthened lately.
The reason for the airport management's decision to implement stricter security measures could be increased criminal activities that could be happening at the airport. Usually, such measures are reactive and not proactive. They are reactive because they respond to what is happening or what has happened in the past. The phrase 'beefed up' in this context means 'made stronger'. The security measures have been made stronger than before or have been strengthened.
So, you may say:
Airport management has implemented stricter security measures than before.
or
Airport security has been beefed up recently.
or
Airport security has been strengthened lately.
空港の警備が厳しくなったのは、空港での犯罪が増えたからかもしれません。たいていこの種のものはリアクションです。過去に起きたこと、今起きていることに対処しているということです。
「beef up」はここでは「強化する」という意味です。警備が強化された、ということですね。
Airport management has implemented stricter security measures than before.
〔訳〕空港の警備が強化された。
Airport security has been beefed up recently.
〔訳〕最近空港のセキュリティが厳しくなった。
Airport security has been strengthened lately.
〔訳〕最近空港のセキュリティが厳しくなった。
Each country has their own laws and regulations about airport security, some countries security is better than others, that way you control what comes in and leaves the country.
Here are some different ways to express that:
"The airport has tightened their security!"
"Airport security has been increased!"
それぞれの国で空港のセキュリティについて法律や規制があります。だれ（何）によって入出国するのかをコントロールできるように、国によって厳しいところもあります。
このことを表現する言い方をお伝えします。
"The airport has tightened their security!"
"Airport security has been increased!"
In English we use the term step up one's game to describe that someone or something has enhanced their way of doing something. For example, if a coworker decided to work more hours because they want a promotion you can say 'She really stepped up her game'. If we need someone to work harder at something we can tell them that they need to step up their game.
「step up one's game」は「改善」「強化」を表す言い方です。
例えば同僚が昇進のために勤務時間を増やしたときは：
'She really stepped up her game'
〔訳〕彼女は本当によく頑張っている。
人にもっと頑張るように言うときには：
Step up your game.
〔訳〕もっと頑張れ。
I see that the securities at the airport are actually working now.
There are more securities at the airport and more rules and regulations too.
>I see that the securities at the airport are actually working now.
*This sentence is a little bit sarcastic in the sense that the security was rather laid back and not really working and let a lot of things slip through. But now it is more strict and meaning that they are taking their jobs more serious now.
.....................................................
>There are more securities at the airport and more rules and regulations too.
*rules= a code of practice
*Regulations=a rule or directive made and maintained by an authority
..........***..........
I see that the securities at the airport are actually working now.
この文章は皮肉的な表現です。
うまく機能していなくて多くのことが見過ごされてしまったので、警戒が強まったことを意味しています。
しかし、今はより厳しくより厳粛になっていることを意味します。
There are more securities at the airport and more rules and regulations too.
*rules= 実施規則
*Regulations=権力による命令や規制を意味します。
We can use either the verbs, "to become," or also, "to get," and have them come out to mean the same thing. We can also rearrange the sentence to, "the airport has stricter security," with, "security," being more the object of the sentence.
日本 
イギリス 
カナダ 
南アフリカ 
アメリカ合衆国 
