Network and wireless network:concepts,application and future不少于三百字的英语作文

Network and wireless network:concepts,application and future不少于三百字的英语作文
Network and wireless network:concepts,application and future
不少于三百字的英语作文

Network and wireless network:concepts,application and future不少于三百字的英语作文
来自维基,概念：Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network
用途：
Wireless networks have had a significant impact on the world as far back as World War II. Through the use of wireless networks, information could be sent overseas or behind enemy lines easily, efficiently and more reliably. Since then, wireless networks have continued to develop and their uses have grown significantly. Cellular phones are part of huge wireless network systems. People use these phones daily to communicate with one another. Sending information overseas is possible through wireless network systems using satellites and other signals to communicate across the world. Emergency services such as the police department utilize wireless networks to communicate important information quickly. People and businesses use wireless networks to send and share data quickly whether it be in a small office building or across the world.[5]
Another important use for wireless networks is as an inexpensive and rapid way to be connected to the Internet in countries and regions where the telecom infrastructure is poor or there is a lack of resources, as in most developing countries.
Compatibility issues also arise when dealing with wireless networks. Different components not made by the same company may not work together, or might require extra work to fix these issues. Wireless networks are typically slower than those that are directly connected through an Ethernet cable.
A wireless network is more vulnerable, because anyone can try to break into a network broadcasting a signal. Many networks offer WEP - Wired Equivalent Privacy - security systems which have been found to be vulnerable to intrusion. Though WEP does block some intruders, the security problems have caused some businesses to stick with wired networks until security can be improved. Another type of security for wireless networks is WPA - Wi-Fi Protected Access. WPA provides more security to wireless networks than a WEP security set up. The use of firewalls will help with security breaches which can help to fix security problems in some wireless networks that are more vulnerable.
前景：In recent times, there have been increased concerns about the safety of wireless communications, despite little evidence of health risks so far.[6] The president of Lakehead University refused to agree to installation of a wireless network citing a California Public Utilities Commission study which said that the possible risk of tumors and other diseases due to exposure to electromagnetic fields (EMFs) needs to be further investigated

The Christmas Tree——圣诞树的故事
Although it is generally agreed that the Christmas tree in its current form came from Germany in the early 19th century, the tradition of decorating a tree to mark win...

全部展开

The Christmas Tree——圣诞树的故事
Although it is generally agreed that the Christmas tree in its current form came from Germany in the early 19th century, the tradition of decorating a tree to mark winter celebrations dates back hundreds of years to Roman times, when they used to decorate evergreen trees with small pieces of metal to celebrate Saturnalia.
In medieval times the 'Paradise Play' was performed every year on 24 December. This depicted the creation of Man and the fall of Adam and Eve from the Garden of Eden and always included an evergreen hung with apples which represented the apple tree of temptation.
There is a legend that St Boniface, an English monk, came upon a group of pagans gathered around an oak tree who were preparing to sacrifice a child to the God Thor. In order to stop the sacrifice, and save the child's life, St Boniface is said to have felled the tree with one blow of his fist. Later on, a fir tree grew in place of the oak and this, St Boniface told the pagans, was the Tree of Life and represented the Christ Child.
Legend also suggests that, in the late 16th century, Martin Luther (the founder of the Protestant religion) was the first to decorate an indoor tree with candles when he attempted to recreate the stars shining over a forest of evergreens.
The first mention of decorated trees being taken indoors came in 1605 in Germany - a country with a long Christmas tree history! The trees were initially decorated with fruit and sweets together with hand made objects such as quilled snowflakes and stars. German Christmas Markets began to sell shaped gingerbreads and wax ornaments which people bought as souvenirs of the fair and took home to hang on their tree.
Tinsel was also invented in Germany in about 1610. Up until fairly recently real silver was used, which was pulled into wafer thin strips by special machines. This was durable but tarnished quickly and many experiments took place to try and find an alternative - including a mix of lead and tin, which was too heavy and kept breaking. It was only in the mid 20th century that a viable alternative was found.
Artificial trees were invented in the 1880's in a bid to try and stop some of the damage being caused to real trees due to people lopping the tip off large trees, thus preventing the trees from growing any further. It got so bad in Germany that laws had to be brought in to prevent people having more than one tree.
Prince Albert, husband of Queen Victoria, is credited with being responsible for introducing the custom of the Christmas tree to the British public by decorating the first English Christmas tree at Windsor Castle in 1841 using candles, sweets, fruit and gingerbread.
The popularity of the Christmas tree grew in Britain during the first half of the 20th century, with trees becoming bigger and more elaborately decorated with bells, baubles and tinsel. However, the onset of the Second World War resulted in a ban on cutting down trees for decoration and people resorted to having small, artificial tabletop trees bearing home made decorations. These were often taken down into the air raid shelters when the sirens sounded to provide a bit of Christmas cheer!
This all changed following the war, and large trees were erected in many public places to celebrate Christmas. The most famous of these is the tree in Trafalgar Square, London which is an annual gift from the Norwegian government to give thanks for the help they received from Britain during the war.
----------------------------------------------------------------------
尽管人们普遍同意，目前形式的圣诞树来到19世纪初从德国，装饰树的传统庆祝活动，庆祝冬天可以追溯到几百年的古罗马时期，当他们用来装饰常绿树木，小金属件庆祝农神节。
在中世纪时代天堂游戏'是每年进行12月24日。这描绘从伊甸园的人创造和亚当和夏娃的减少，包括常绿总是挂着苹果占各种诱惑的苹果树。
尽管人们普遍同意，目前形式的圣诞树来到19世纪初从德国，装饰树的传统庆祝活动，庆祝冬天可以追溯到几百年的古罗马时期，当他们用来装饰常绿树木，小金属件庆祝农神节。
有一种传说，圣博尼费斯，英国僧侣，经周围的异教徒一棵橡树谁正准备牺牲一个孩子的上帝托尔聚集一群。为了阻止的牺牲，并保存儿童的生命，圣博尼费斯据说砍伐与他的一个拳头打击树。后来，一棵枞树在橡树和这个地方的增长，圣博尼费斯说的异教徒，
是生命之树，代表基督儿童。
联想还表明，在16世纪末期，马丁路德（新教的宗教创始人）是第一个与蜡烛装饰室内树当他试图重新创建星级以上的常绿树林光辉。
装饰树木的第一次提到正在采取室内排在1605年在德国-具有悠久历史的圣诞树一个国家！最初的树木装饰与水果和糖果等quilled了雪花，星星对象共进。
德国圣诞市场开始销售，并形成gingerbreads人们购买作为纪念品蜡饰品公平，并最终保住自己的树。
直到20世纪中叶，一个可行的办法是找到。
人工树发明的，以试图阻止一些损害1880年是造成人们免除了因关闭大树的小费真的树，从而防止任何进一步的生长的树木。它变得如此恶劣，在德国的法律，而且要防止人以上的树还出现了。
艾伯特王子，维多利亚女王的丈夫，是记入负责引进来装饰圣诞节前在英国温莎城堡树的圣诞树习惯，在1841年英国公众使用蜡烛，糖果，水果和姜饼。
金属丝还发明了在德国1610年左右。直到不久以前的实际用银，这是车到晶圆特种机械细条状。这是持久的，但受损迅速发生了许多实验，包括铅和锡，这是太重，不断打破组合，试图找到一种替代- 。
这些常常被纳入了防空洞的警报响起时，提供一份圣诞欢呼位！
该圣诞树普及了英国在20世纪上半叶，树木变得更大，更精心钟，中看不中用的物品和金属丝装饰。然而，第二次世界大战的爆发导致了关于削减装潢和采取了一些小，人工影响了桌上树人树木装饰家居的禁令。

收起