为了孩子啥都能忍。 Love? I do not care. Money? I do not care. 我真的感觉俺是天下最好的爸爸。
b*5
2 楼
这年头, 问题问的千变万化的。 这家用C做ad targeting。 1) 问我一个coding test应该怎么improve。 其实就是要写read, 我用了fread。 问我fread和read什么区别。 我这C都不知什么时候用的了, 早忘了 2) 然后再问, what happens when u use new/malloc. 其实是要问unix/windows system command that allocates memory, like brk.. 3) 然后问, 比如一个integer array, 32 elements, 32 threads running on 32 processors, i find a lot of idle cpu time. why? 其实就是问什么是false sharing. 听都没听说过。 问到了L1, L2 cache...
O*l
3 楼
看到EB3三月份的filing排期已经前进到了2015年五月,而EB2还在2013年。听到不少人 说过EB2 downgrade到EB3, 新手不太了解怎么回事。是否可以将NIW case downgrade到 EB3来递交485? 谢谢!
p*m
4 楼
Wi-Fi Advanced 802.11ah IEEE 802.11ah is a new PHY and MAC design that operates in the sub-one- gigahertz (900MHz) band. 11ah is intended to support extended range WiFi, and the Internet-of-everything (IoE). The 11ah PHY and MAC are optimized from the ground up for extended range, power efficiency, and scalable operation. The new 11ah design enhances link-budget compared to 2.4GHz technologies. 11ah supports mandatory and globally interoperable 1 and 2 MHz bandwidth modes which open up new use cases for WiFi: IoE, home automation, smart grid, wearable consumer electronics, low-power sensors, etc. 11ah also supports 4, 8, and 16 MHz bandwidths for higher-data rate applications (e.g. in the US where 26MHz is available in 900 MHz band). 11ah extends the range of WiFi beyond the limited range of 2.4 and 5 GHz by leveraging the improved propagation and penetration of 900MHz radio waves through walls and obstructions. With 11ah, WiFi coverage improves in previously hard to reach places such as garages, back yards, attics, buildings, factories, malls, etc. A single 11ah AP can provide whole home coverage. It can also support low cost battery powered sensors operating without a power amplifier and which use interoperable 1&2 MHz bandwidth modes. A 150 Kbps minimum data rate results in short on-time for sensors with short bursty data packets thus lowering their power consumption. Overall power is also reduced by using lower power MAC protocols such as smaller frame formats, sensor traffic priority, and beaconless paging mode. 11ah MAC is also optimized to scale to thousands of nodes by using efficient paging and scheduled transmissions. 11ah leverages the WiFi ecosystem & IP network for easy setup & pairing to AP/mobiles. 11ah devices are interoperable across vendors. 11ah is being standardized in IEEE with a draft 2.0 version expected in mid- 2014. Qualcomm’s WiFi Advanced, along with other participants have been leading these standardization efforts.
I*5
5 楼
你肯定是科大的
u*o
6 楼
然后再问, what happens when u use new/malloc. 其实是要问unix/windows system command that allocates memory, like brk.. 这题问题和答案有什么关系。。。
国际上规定用于加热和干燥的微波频率有 4段,分别为:L 段,890MHz~940MHz;S 段 , 频率为 2.4GHz~2.5GHz; C 段, 频率为 5.725GHz~5.875GHz; K 段, 频率为 2.2GHz~2.225GHz。而家用微波炉的频段为 L 段和 S 段,其中又以 S 段居多。
估计带宽有限,主要是range and power, 给internet of things 用的。
MHz automation,
【在 p*******m 的大作中提到】 : Wi-Fi Advanced : 802.11ah : IEEE 802.11ah is a new PHY and MAC design that operates in the sub-one- : gigahertz (900MHz) band. 11ah is intended to support extended range WiFi, : and the Internet-of-everything (IoE). The 11ah PHY and MAC are optimized : from the ground up for extended range, power efficiency, and scalable : operation. The new 11ah design enhances link-budget compared to 2.4GHz : technologies. 11ah supports mandatory and globally interoperable 1 and 2 MHz : bandwidth modes which open up new use cases for WiFi: IoE, home automation, : smart grid, wearable consumer electronics, low-power sensors, etc. 11ah