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创业公司Firebase提供实时数据后端,让你使用JavaScript就能创建高品质数据驱动的动态网站

April 21, 2012 Leave a comment

36氪

via 创业公司Firebase提供实时数据后端,让你使用JavaScript就能创建高品质数据驱动的动态网站.


如果你使用 Dropbox 或者同类网盘就会知道,在同步文件夹里的文件如果有被更新,添加或者删除,在其他已链接的终端的文件夹里也会发生相同的变化,保持同步状态。Firebase 也是类似的云服务,不同于 Dropbox 的「文件」,Firebase 同步的是「数据」,服务对象是网站开发者,帮助他们开发具有「实时」(Real-Time)特性的应用。

前不久我们向大家介绍了 Meteor ,这是一个开源的实时 Web 应用框架。Firebase 和 Meteor 同样具有实时数据更新的本质特性,但 Firebase 更加彻底,开发者只需引用一个 API 库文件就可以使用标准 REST API 的各种接口对数据进行读写操作,只需编写 HTML+CSS+JavaScrip 前端代码,不需要服务器端代码(如需整合,也及其简单),省下的时间可以让开发者专注于开发应用功能,完善设计和体验,解决用户的实际问题。

和绝大多数云服务一样,不需要额外的服务器硬件设备,并且是可以随时扩展的,对数据存储容量没有限制,Firebase 最高能处理百万级的并发和 TB 级的数据传输,数据发生更改,同步敏感颗粒度基本达到10毫秒级别。Firebase 用法也足够简单,页面完全是标准 HTML 代码,数据读取和展现使用 JSON API 就可以完成,使用 Firebase 开发应用最快的纪录只要几分钟,iPhone 上的 Mobile Graffiti 应用,是一个4个人的团队仅用了34小时开发的,可以把手机当作虚拟画笔,实时绘制图像,通过 Firebase 数据后端实时传输到他们网站的画布上展现出来。Firebase 宣布启动一周后,已有超过4000名开发者注册。

当然,作为一项非常新的技术,Firebase 还在不断开发完善中,当前存在的最大的问题可能是,Firebase 上的数据都是完全公开的,每一个数据片段都可以通过独立的 URL 访问到,这样构建有敏感信息的应用时需要非常小心。

Google 在2009年中推出的前瞻性个人信息和协作工具 Google Wave,让人们畅想了下一代网络「实时」的特新,在 Wave 中,你正在打字时输入的每个字符,参与会话的人都能立即看到。不过 Wave 的性能或许并不理想,用户常遇到服务器宕机的错误提示,用户电脑也会出现 CPU 超高负荷和内存被大量占用,出现电脑反映缓慢甚至死机的情况。

下一个 Web 时代,「实时」将是基本特性之一,性能是用户体验好坏的先决条件,现在看来 Firebase 或者 Meteor 的性能方面表现还相当不错,你看好么?

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New Research Could Mean Cellphones That Can See Through Walls

April 21, 2012 Leave a comment

Team Finds New Possibilities in Untapped Terahertz Range With Implications For a Host of Devices

Apr. 18, 2012

TxACE director Kenneth O (left), professor of electrical engineering, with member Dae Yeon KimDr. Kenneth O, director of the Texas Analog Center of Excellence and a professor of electrical engineering, left, worked with a team including Dae Yeon Kim, who was among the authors of the research report.

Comic book hero superpowers may be one step closer to reality after the latest technological feats made by researchers at UT Dallas. They have designed an imager chip that could turn mobile phones into devices that can see through walls, wood, plastics, paper and other objects.

The team’s research linked two scientific advances. One involves tapping into an unused range in the electromagnetic spectrum. The other is a new microchip technology.

The electromagnetic spectrum characterizes wavelengths of energy. For example, radio waves for AM and FM signals, or microwaves used for cell phones or the infrared wavelength that makes night vision devices possible.

But the terahertz band of the electromagnetic spectrum, one of the wavelength ranges that falls between microwave and infrared, has not been accessible for most consumer devices.

“We’ve created approaches that open a previously untapped portion of the electromagnetic spectrum for consumer use and life-saving medical applications,” said Dr. Kenneth O, professor of electrical engineering at UT Dallas and director of the Texas Analog Center of Excellence (TxACE).  “The terahertz range is full of unlimited potential that could benefit us all.”

Tapping the Terahertz Gap

Shown is the electromagnet spectrum, from radio waves used for FM and AM signals, to infrared waves used for remote controls, to gamma rays that kill cancer cells.  A team at UT Dallas is focusing on the “terahertz band,” which has not been accessible for most consumer devices.

Tapping the Terahertz Gap

Using the new approach, images can be created with signals operating in the terahertz (THz) range without having to use several lenses inside a device. This could reduce overall size and cost.

The second advance that makes the findings applicable for consumer devices is the technology used to create the microchip. Chips manufactured using CMOS (Complementary Metal-Oxide Semiconductor) technology form the basis of many consumer electronic devices used in daily life such as personal computers, smart phones, high definition TV and game consoles.

“CMOS is affordable and can be used to make lots of chips,” Dr. O said. “The combination of CMOS and terahertz means you could put this chip and a transmitter on the back of a cellphone, turning it into a device carried in your pocket that can see through objects.”  Due to privacy concerns, Dr. O and his team are focused on uses in the distance range of less than four inches.

Consumer applications of such technology could range from finding studs in walls to authentication of important documents. Businesses could use it to detect counterfeit money. Manufacturing companies could apply it to process control.  There are also more communication channels available in terahertz than the range currently used for wireless communication, so information could be more rapidly shared at this frequency.

“The combination of CMOS and terahertz means you could put this chip and receiver on the back of a cellphone, turning it into a device carried in your pocket that can see through objects.”

Dr. Kenneth O,
Texas Instruments Distinguished Chair, TxACE director

Terahertz can also be used for imaging to detect cancer tumors, diagnosing disease through breath analysis, and monitoring air toxicity.

“There are all kinds of things you could be able to do that we just haven’t yet thought about,” said Dr.  O, holder of the Texas Instruments Distinguished Chair.

The research was presented at the most recent International Solid-State Circuits Conference (ISSCC). The team will work next to build an entire working imaging system based on the CMOS terahertz system.

Other authors of the paper include Ruonan Han and Yaming Zhang, former students of Professor O, Youngwan Kim and Dae Yeon Kim, TxACE members,  and Hisashi Sam Shichijio, research professor at TxACE.

The work was supported by the Center for Circuit & System Solutions (C2S2 Center) and conducted in the TxACE laboratory at UT Dallas, which is funded by the Semiconductor Research Corporation (SRC), the state through its Texas Emerging Technology Fund, Texas Instruments Inc., The UT System and UT Dallas.


Media Contact: LaKisha Ladson, UT Dallas, (972) 883-4183, lnl120030@utdallas.edu
or the Office of Media Relations, UT Dallas, (972) 883-2155, newscenter@utdallas.edu.

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