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What is Tax Cut
What is J1 Visa
What is your internet speed
How does VOIP work
What is GSM
What is CDMA
What is Wireless Electricity
What is Tax Cut
A tax cut is a reduction in taxes. Economic stimulus via tax cuts, along with interest rate intervention and deficit spending, are one of the central tenets of Keynesian economics.
The immediate effects of a tax cut are, generally, a decrease in the real income of the government and an increase in the real income of those whose tax rate has been lowered. In the longer term, however, the effect on government income may be reversed, depending on the response that tax-payers make. Depending on the original tax rate, tax cuts may provide individuals and corporations with an incentive for investments which stimulate so much economic activity that even at the lower rate more net tax revenue will be collected.
The longer term macroeconomic effects of a tax cut are not predictable in general, because they depend on how the taxpayers use their additional income and how the government adjusts to its reduced income. Three idealised scenarios can be hypothesised:
1. Government cuts its expenditure, and taxpayers increase theirs, spending the money on commodities sourced from within the country. This combination is macroeconomically neutral, but advocates of a free-market economy argue that it improves economic welfare, since people are more accurate than the government in spending money on commodities that they actually want.
2. Government maintains its expenditure (thus incurring debt), and taxpayers increase theirs, spending the money on commodities sourced from within the country. This combination provides a stimulus to the economy, and it is on these grounds that advocates of supply-side economics frequently argue for tax cuts. It should lead to economic growth, bringing about greater general prosperity, though unless managed carefully it will also lead to inflation. A government making tax cuts and incurring debt usually hopes that the economic stimulus of the tax cut will be large enough to produce a long-term increase in tax revenues, allowing the debt to be paid off in the future. If that does not occur then the government can be left with a severe budgetary crisis.
3. Government maintains its expenditure (thus incurring debt), and taxpayers either save their increased income or spend it on commodities sourced from outside the country. This combination is not inherently deflationary, but it contributes to balance of payments difficulties which may have secondary deflationary effects and as noted above may lead to a government budgetary crisis with a painful readjustment to follow.
In practice it is likely that a mixture of these effects will occur, and the net effect of any tax cut will depend on the balance between them. It will therefore be a function of the overall state of the national economy. In conditions where most goods and services (especially those frequently purchased out of discretionary income, such as consumer durables) are produced domestically, a tax cut is more likely to provide a macroeconomic stimulus than in conditions where most consumer durables are imported. Furthermore, the actual effect will inevitably be difficult to discern, because of numerous other changes in the economy between the time when a tax cut is proposed and the time when its full effects would be realized.
If government does reduce its expenditure to accommodate tax cuts, there must necessarily be reductions in government services, and there may also be a reduction of the government's capacity to redistribute income to reduce income inequalities. Critics of tax cuts argue that this leads to a fall in overall economic welfare because the effects fall disproportionately on those with the lowest incomes.
What is J1 Visa
J-1 visa is a non-immigrant visa issued by the United States to exchange visitors participating in programs that promote cultural exchange. Applicants must meet eligibility criteria and be sponsored either by a private sector or government program.
J-1 visa holders are expected to leave the United States for their home country upon the completion of their J-1 program. For the purpose of travelling exchange visitors are granted a 30-day grace period in addition to the time determined by their program. All holders of J-1 visas are required to be entered into the SEVIS tracking system.
There are different program categories of J-1 visa, each serving a specific type of exchange. The eligibility requirements and maximum allowed length of visa varies between programs.
Private sector programs:
* Alien Physician
* Au Pair and EduCare
* Camp Counselor
* Student, Secondary School
* Trainee and Flight Training
Government and academic programs:
* Government Visitor
* International Visitor
* Professor and Research Scholar
* Short-Term Scholar
* Student, College/University
What is your internet speed
How to get more accurate internet speed test results
Your internet connection speed can be affected by many factors. To help achieve the most accurate test results, please follow these simple steps:
* Close any other open browser windows you may have open.
* Close any programs that you have running which may be connecting to the internet.
* Run this speed test at different times of the day and different days of the week. Network usage will vary depending on the time of day and your speed may be directly affected by the changes in the network.
Use the following to test your connection speed
How does VOIP work
It is very easy to get into a discussion that is very technical and confusing to most readers. The purpose of this section will be to provide a very high-level overview of Voice over IP (VoIP) aimed at those who do not consider themselves experts in the subject and hopefully with enough clarity that it serves as a good introduction to most readers.
Many people have used a computer and a microphone to record a human voice or other sounds. The process involves sampling the sound that is heard by the computer at a very high rate (at least 8,000 times per second or more) and storing those "samples" in memory or in a file on the computer. Each sample of sound is just a very tiny bit of the person's voice or other sound recorded by the computer. The computer has the wherewithal to take all of those samples and play them, so that the listener can hear what was recorded.
VoIP is based on the same idea, but the difference is that the audio samples are not stored locally. Instead, they are sent over the IP network to another computer and played there.
Of course, there is much more required in order to make VoIP work. When recording the sound samples, the computer might compress those sounds so that they require less space and will certainly record only a limited frequency range. There are a number of ways to compress audio, the algorithm for which is referred to as a "compressor/de-compressor", or simply CODEC. Many CODECs exist for a variety of applications (e.g., movies and sound recordings) and, for VoIP, the CODECs are optimized for compressing voice, which significantly reduce the bandwidth used compared to an uncompressed audio stream. Speech CODECs are optimized to improve spoken words at the expense of sounds outside the frequency range of human speech. Recorded music and other sounds do not generally sound very good when passed through a speech CODEC, but that is perfectly OK for the task at hand.
Once the sound is recorded by the computer and compressed into very small samples, the samples are collected together into larger chunks and placed into data packets for transmission over the IP network. This process is referred to packetization. Generally, a single IP packet will contain 10 or more milliseconds of audio, with 20 or 30 milliseconds being most common.
Vint Cerf, who is often called the Father of the Internet, once explained packets in a way that is very easy to understand. Paraphrasing his description, he suggested to think of a packet as a postcards sent via postal mail. A postcard contains just a limited amount of information. To deliver a very long message, one must send a lot of postcards. Of course, the post office might lose one or more postcards. One also has to assemble the received postcards in order, so some kind of mechanism must be used to properly order to postcards, such as placing a sequence number on the bottom right corner. One can think of data packets in an IP network as postcards.
Just like postcards sent via the postal system, some IP data packets get lost and the CODECs must compensate for lost packets by "filling in the gaps" with audio that is acceptable to the human ear. This process is referred to as packet-loss concealment (PLC). In some cases, packets are sent multiple times in order to overcome packet loss. This method is called, appropriately enough, redundancy. Another method to address packet loss, known as forward-error correction (FEC), is to include some information from previously transmitted packets in subsequent packets. By performing mathematical operations in a particular FEC scheme, it is possible to reconstruct a lost packet from information bits in neighboring packets.
Packets are also sometimes delayed, just as with the postcards sent through the post office. This is particularly problematic for VoIP systems, as delays in delivering a voice packet means the information is too old to play. Such old packets are simply discarded, just as if the packet was never received. This is acceptable, as the same PLC algorithms can smooth the audio to provide good audio quality.
Computers generally measure the packet delay and expect the delay to remain relatively constant, though delay can increase and decrease during the course of a conversation. Variation in delay (called jitter) is the most frustrating for IP devices. Delay, itself, just means it takes longer for the recorded voice spoken by the first person to be heard by the user on the far end. In general, good networks have an end-to-end delay of less than 100ms, though delay up to 400ms is considered acceptable (especially when using satellite systems). Jitter can result in choppy voice or temporary glitches, so VoIP devices must implement jitter buffer algorithms to compensate for jitter. Essentially, this means that a certain number of packets are queued before play-out and the queue length may be increased or decreased over time to reduce the number of discarded, late-arriving packets or to reduce "mouth to ear" delay. Such "adaptive jitter buffer" schemes are also used by CD recorders and other types of devices that deal with variable delay.
Video works in much the same way as voice. Video information received through a camera is broken into small pieces, compressed with a CODEC, placed into small packets, and transmitted over the IP network. This is one reason why VoIP is promising as a new technology: adding video or other media is relatively simple. Of course, there are certain issues that must be considered that are unique to video (e.g., frame refresh and much higher bandwidth requirements), but the basic principles of VoIP equally apply to video telephony.
Of course there is much more to VoIP than just sending the audio/video packets over the Internet. There must also be an agreed protocol for how computers find each other and how information is exchanged in order to allow packets to ultimately flow between the communicating devices. There must also be an agreed format (called payload format) for the contents of the media packets. We will describe some of the popular VoIP protocols in the next section.
Through this section, we have focused on computers that communicate with each other. However, VoIP is certainly not limited to desktop computers. VoIP is implemented in a variety of hardware devices, including IP phones, Aanalog terminal adapters (ATAs), and gateways. In short, a large number of devices can enable VoIP communication, some of which allow one to use traditional telephone devices to interface with the IP networks: one does not have to throw out existing equipment to migrate to VoIP.
What is GSM
GSM (Global System for Mobile communication) is a digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of Time Division Multiple Access (TDMA) and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900 MHz or 1,800 MHz frequency band.
GSM is the de facto wireless telephone standard in Europe. GSM has over one billion users worldwide and is available in 190 countries. Since many GSM network operators have roaming agreements with foreign operators, users can often continue to use their mobile phones when they travel to other countries.
What is CDMA
CDMA stands for Code Division Multiple Access. It is a technique used for digital communication, and wireless technology in particular, that involves multiplexing. Whereas conventional communication systems use constant frequencies, CDMA uses multiple access, or multiplexing. Multiplexing, in this case accomplished through the specific type known as spread spectrum, uses varied frequencies to transmit audio signals. This, coupled with code division which requires a certain code to send and receive the frequency, further protects CDMA communications from interference.
Radio systems, one of the earliest forms of telecommunication, required users to have distinct frequencies. Two earlier forms of wireless communication illustrated the limits of methods previous to CDMA. Frequency Division Multiple Access or FDMA only allowed users to operate on a single frequency. For instance, when tuning in to a radio to get sound, a listener must select one frequency or the other. The listener must also tune the frequency to filter out noise in the spectrum that is not associated with one frequency or the other.
The other form of early radio communication was Time Division Multiple Access or TDMA. In this case, users could not share a frequency and each user had to coordinate his or her turn on that frequency in order to communicate. Both FDMA and TDMA posed restrictions for early users, particularly the military. As early as World War II, the military needed to communicate across vast distances that required wireless technology. That was also the case for their adversaries. Military communication units did not have time to wait their turn to transmit sound, or to find a frequency.
Previous telecommunication systems allowed military communication units to transmit sound into the same spectrum their adversaries used. The military’s signals needed a unique identification through a distinct code to avoid interference from enemy communication. The receiver of that message on the other end could similarly retrieve the message based on its unique code in the spectrum.
Just as the radio moved from military use to commercial use, so too was the case with the wireless technology. CDMA became the early choice for personal communication because it could allow multiple users to communicate within the spectrum, avoiding interference or blocking among users. In 1999, CDMA became the standard technology for the telecommunications industry for its growing wireless systems. Since there are large numbers of users in the system communicating at the same time, code division ensures that each user’s signal remains separate in the spectrum.
What is Wireless Electricity
Scientists have known for nearly two centuries how to transmit electricity without wires, and the phenomenon has been demonstrated several times before. But it wasn't until the rise of personal electronic devices that the demand for wireless power materialized. In the past few years, at least three companies have debuted prototypes of wireless power devices, though their distance range is relatively limited [see "Power Brokers," next page]. Then last year, a team at the Massachusetts Institute of Technology set the stage for wireless power that works from across a room.
The key to wireless power is resonance. Think of a wineglass that shatters when an opera singer hits just the right note. When the voice matches the glass's resonant frequency—the tone you hear when you tap the glass—the glass efficiently absorbs the singer's energy and cracks. Using magnetic induction and two identical copper coils that resonate at the same frequency, the MIT scientists successfully powered a 60-watt lightbulb from a power source seven feet away. The team called their invention WiTricity, short for "wireless electricity." Next up: sending the juice even farther and more efficiently.
Power Brokers: Steps Toward a Cordless World
More than a century ago, physicist Nikola Tesla envisioned a future in which power stations would beam electricity directly into homes and businesses. He built a 20-story transmission tower on Long Island with the goal of demonstrating such a feat, but it never became operational. The Serbian immigrant died a pauper.
Fulton Innovation's eCoupled:
Like MIT, eCoupled uses paired coils to transmit power, though over much shorter distances. A year ago, Fulton Innovations demonstrated pads and car cups that charge devices placed on or inside them. The company is now working with Motorola and Herman Miller to develop gadget-powering office furniture.
Early last year, the Pennsylvania company Powercast unveiled several prototypes powered by radio waves from a transmitter hidden inside a household object such as a desk lamp. The system delivers a couple watts over short
distances. Wireless holiday lights were available as of the end of last year.
MIT first demonstrated WiTricity midlast year, lighting an incandescent bulb many feet distant from the powering coil. "Electricity [already] comes to our walls," Karalis says. "We just want to bring it from there to the center of our rooms wirelessly." The university is in talks with companies interested in commercializing the technology.
What's WiTricity good for?
It could eliminate that rat's nest of cords under your desk. You would no longer have to wrangle for an outlet at business conferences. And your home would keep your gadgets constantly powered up.
Can a single transmitting coil power multiple devices?
Will WiTricity be just like Wi-Fi networks today?
Yes, although like Wi-Fi, WiTricity could be free in some locations and a for-fee service in others. Creating a standard frequency that would allow all your gadgets to be powered at all WiTricity hotspots is an issue.
Will batteries become obsolete?
No. Items (like laptops) that we use indoors might not require batteries. But gadgets like cameras that we use on the go would still need them.
What if my dog fell asleep between the wall coil and my computer?
"Line of sight is not required," says MIT doctoral student Aristeidis Karalis, who did many of the calculations and predictions for the system. But because the transfer efficiency declines with distance, each room would need its own distributing coil.
But will it give my dog cancer?
Biological organisms are not strongly affected by magnetic fields, and the MIT team believes that safety won't be a concern. Still, more experiments will be needed.