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But of course, there are also the true mobile, wireless applications, ranging from the portable office to people walking around a store with a PDA doing inventory. At many busy airports, car rental return clerks work in the parking lot with wireless portable computers. They type in the license plate number of returning cars, and their portable, which has a built-in printer, calls the main computer, gets the rental information, and prints out the bill on the spot.

As wireless technology becomes more widespread, numerous other applications are likely to emerge. Let us take a quick look at some of the possibilities. Wireless parking meters have advantages for both users and city governments. The meters could accept credit or debit cards with instant verification over the wireless link. When a meter expires, it could check for the presence of a car (by bouncing a signal off it) and report the expiration to the police. It has been estimated that city governments in the U.S. alone could collect an additional $10 billion this way (Harte et al., 2000). Furthermore, better parking enforcement would help the environment, as drivers who knew their illegal parking was sure to be caught might use public transport instead.
随着无线技术的不断普及,许多其他方面的应用也在不断涌现。让我们来看看其中一些可能的应用。无线停车计时器,对用户和城市管理都能带来很多便利。通过无线连接,这种计时器可以接受信用卡或借记卡进行即时验证。当计时器超过设定的时间后,无线网络可以检测是否还停有汽车(通过回复信号),并报告警察汽车停车超时。据估计,仅美国的城市管理通过使用这种技术便能追加100亿美元的税收(Harte et al., 2000)。而且,更好的停车秩序有助于改善环境,比如,知道非法停车肯定被抓后,司机们反而可能使用公共交通工具出行。

Food, drink, and other vending machines are found everywhere. However, the food does not get into the machines by magic. Periodically, someone comes by with a truck to fill them. If the vending machines issued a wireless report once a day announcing their current inventories, the truck driver would know which machines needed servicing and how much of which product to bring. This information could lead to more efficient route planning. Of course, this information could be sent over a standard telephone line as well, but giving every vending machine a fixed telephone connection for one call a day is expensive on account of the fixed monthly charge.

Another area in which wireless could save money is utility meter reading. If electricity, gas, water, and other meters in people's homes were to report usage over a wireless network, there would be no need to send out meter readers. Similarly, wireless smoke detectors could call the fire department instead of making a big noise (which has little value if no one is home). As the cost of both the radio devices and the air time drops, more and more measurement and reporting will be done with wireless networks.

A whole different application area for wireless networks is the expected merger of cell phones and PDAs into tiny wireless computers. A first attempt was tiny wireless PDAs that could display stripped-down Web pages on their even tinier screens. This system, called WAP 1.0 (Wireless Application Protocol) failed, mostly due to the microscopic screens, low bandwidth, and poor service. But newer devices and services will be better with WAP 2.0.
无线网络的一个截然不同的应用领域是期待吸收手机和PDAs的优点应用到微型无线计算机的内部。最初的设想是,使微型无线PDAs在很微小的屏幕上显示简化后的网页。这个称为WAP 1.0 (Wireless Application Protocol无线应用协议)的系统没有实现这项功能,大部分是由于太微型的屏幕、较低的带宽及服务不当。但是,更新的WAP 2.0将提供更好设备和服务。
posted on 2006-04-14 11:57 我的翻译博客 阅读(408) 评论(0)  编辑 收藏 引用 所属分类: 计算机软件