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Contemporary Educational Psychology/Chapter 5: Students with Special Educational Needs/Physical and Sensory Impairments

Physical Disabilities and Sensory Impairments
A few students have serious physical, medical or sensory challenges that interfere with their learning. Usually, the physical and medical challenges are medical conditions or diseases that requiring ongoing medical care. The sensory challenges are usually a loss either in hearing or in vision, or more rarely in both. Whatever the specific problem, it is serious enough to interfere with activities in regular classroom programs and to qualify the student for special educational services or programs.

Physical challenges that are this serious are relatively infrequent compared to some of the other special needs discussed in this chapter, though they are of course important in the lives of the students and their families, as well as important for teachers to accommodate. Only about one per cent of students have a hearing loss serious enough to be served by special programs for such students (United States Department of Education, 2005). Only about half that number have visual impairments the lead them to be served by special programs. For two reasons, though, these figures are a bit misleading. One reason is that many more students have vision or hearing problems that are too mild (such as wearing eyeglasses for “ordinary” nearsightedness). Another is that some students with serious sensory impairments may also have other disabilities and therefore not be counted in statistics about sensory impairments.

Hearing Loss
A child can acquire a hearing loss for a variety of reasons, ranging from disease early in childhood, to difficulties during childbirth, to reactions to toxic drugs. In the classroom, however, the cause of the loss is virtually irrelevant because it makes little difference in how to accommodate a student’s educational needs. More important than the cause of the loss is its extent. Students with only mild or moderate loss of hearing are sometimes called hearing impaired or hard of hearing; only those with nearly complete loss are called deaf. As with other sorts of disabilities, the milder the hearing loss, the more likely you are to encounter the student in a regular classroom, at least for part of the day.

Signs of Hearing Loss
Although determining whether a student has a hearing loss may seem straightforward (“Just give a hearing test!”), the assessment is often not clearcut if its takes the student’s daily experiences into account. A serious or profound hearing loss tends to be noticed relatively quickly and therefore often receive special help (or at least receives additional diagnosis) sooner. Mild or moderate hearing loss is much more common, however, and is more likely to be overlooked or mistaken for some other sort of learning problem (Sherer, 2004). Students with a mild hearing loss sometimes have somewhat depressed (or lowered) language and literacy skills—though not always, and in any case so do some students without any loss. They may also seem not to listen or attend to a speaker because of trouble in locating the source of sounds—but then again, sometimes students without loss also fail to listen, though for entirely different reasons. Students with hearing loss may frequently give incorrect answers to questions—but so do certain other students with normal hearing. In addition, partial hearing loss can be hidden if the student teaches himself or herself to lip read, for example, or is careful in choosing which questions to answer in a class discussion. And so on. Systematic hearing tests given by medical or hearing specialists can resolve some of these ambiguities. But even they can give a misleading impression, since students’ true ability to manage in class depends on how well they combine cues and information from the entire context of classroom life.

In identifying a student who may have a hearing loss, therefore, teachers need to observe the student over an extended period of time and in as many situations as possible. In particular, look for a persistent combination of some of the following, but look for them over repeated or numerous occasions (Luckner & Carter, 2001):
 * delayed language or literacy skills, both written and oral
 * some ability (usually partial) to read lips
 * less worldly knowledge than usual because of lack of involvement with oral dialogue and/or delayed literacy
 * occasionally, tendency to social isolation because of awkwardness in communication

Teaching Students with Hearing Loss
In principle, adjustments in teaching students with hearing loss are relatively easy to make though they do require deliberate actions or choices by the teacher and by fellow students. Interestingly, many of the strategies make good advice for teaching all students!
 * Take advantage of the student’s residual hearing. Seat the student close to you if you are doing the talking, or close to key classmates if the students are in a workgroup. Keep competing noise, such as unnecessary talking or whispering, to a minimum (because such noise is especially distracting to someone with a hearing loss). Keep instructions concise and to-the-point. Ask the student occasionally whether he or she is understanding.
 * Use visual cues liberally. Make charts and diagrams wherever appropriate to illustrate what you are saying. Look directly at the student when you are speaking to him or her (to facilitate lip reading). Gesture and point to key words or objects—but within reason, not excessively. Provide handouts or readings to review visually the points that you make orally.
 * Include the student in the community of the classroom. Recruit one or more classmates to assist in “translating” oral comments that the student may have missed. If the student uses American Sign Language (ASL) at home or elsewhere, then learn a few basic, important signs of ASL yourself (“Hello,” “thank you,” “How are you?”). Teach them to classmates as well.

Visual Impairment
Students with visual impairments have difficulty seeing even with corrective lenses. Most commonly the difficulty has to do with refraction (the ability to focus), but some students may also experience a limited field of view (called tunnel vision) or be overly sensitive to light in general. As with hearing loss, labels for visual impairment depend somewhat on the extent and nature of the problem. Legal blindness means that the person has significant tunnel vision or else visual acuity (sharpness of vision) of 20/200 or less, which means that he or she must be 20 feet away from an object that a person with normal eyesight can see at 200 feet. Low vision means that a person has some vision usable for reading, but often needs a special optical device such as a magnifying lens for doing so. As with hearing loss, the milder the impairment, the more likely that a student with a vision problem will spend some or even all the time in a regular class.

Signs of Visual Impairment
Students with visual impairments often show some of the same signs as students with simple, common nearsightedness. The students may rub their eyes a lot, for example, blink more than usual, or hold books very close to read them. They may complain of itchiness in their eyes, or of headaches, dizziness, or even nausea after doing a lot of close eye work. The difference between the students with visual impairment and those with “ordinary” nearsightedness is primarily a matter of degree: the ones with impairment show the signs more often and more obviously. If the impairment is serious enough or has roots in certain physical conditions or disease, they may also have additional symptoms, such as crossed eyes or swollen eyelids. As with hearing loss, the milder forms ironically can be the most subtle to observe and therefore the most prone to being overlooked at first. For classroom teachers, the best strategy may be to keep track of a student whose physical signs happen in combination with learning difficulties, and for whom the combination persists for many weeks.

Teaching Students with Visual Impairment
In general, advice for teaching students with mild or moderate visual impairment parallels the advice for teaching students with hearing loss, though with obvious differences because of the nature of the students’ disabilities.
 * Take advantage of the student’s residual vision. If the student still has some useful vision, place him or her where he can easily see the most important parts of the classroom—whether that is you, the chalkboard, a video screen, or particular fellow students. Make sure that the classroom, or at least the student’s part of it, is well lit (because good lighting makes reading easier with low vision). Make sure that handouts, books and other reading materials have good, sharp contrast (also helpful with a visual impairment).
 * Use non-visual information liberally. Remember not to expect a student with visual impairment to learn information that is by nature only visual, such as the layout of the classroom, the appearance of photographs in a textbook or of story lines in a video. Explain these to the student somehow. Use hands-on materials wherever they will work, such as maps printed in three-dimensional relief or with different textures. If the student knows how to read Braille (an alphabet for the blind using patterns of small bumps on a page), allow him to do so.
 * Include the student in the community of the classroom. Make sure that the student is accepted as well as possible into the social life of the class. Recruit classmates to help explain visual material when necessary. Learn a bit of basic Braille and encourage classmates to do the same, even if none of you ever become as skilled with it as the student himself or herself.

(back to Chapter 5...)


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Communication Networks/Network Basics

What are networks?
Networks are large distributed systems designed to send information from one location to another. An end point is a place in a network where data transmission either originates or terminates. A node is a point in the network where data travels through without stopping. Nodes are connected by channels, paths that data flows down. Channels can be physical linear objects such as a wire or a fiber optic cable, or it can be less tangible, like a wireless connection at a particular frequency.

Providers and consumers
An end point that produces information is known as a producer or a server. An endpoint that receives information is known as a consumer or a client. In many networks, such as bi-directional networks, an endpoint can be both a client and a server.

Bi-directional communications
Bi-directional communications means that data is flowing both to and from an end point. An end point can be both a client and a server.

Point-to-point communication
Some channels are point-to-point: they have only a single producer (at one end), and a single consumer (at the far end).

Many networks have "full duplex" communication between nodes, meaning they have 2 separate point-to-point channels (one in each direction) between the nodes (on separate wires or allocated to separate frequencies).

Some "mesh" networks are built from point-to-point channels. Since wiring every node to every other node is prohibitively expensive, when one node needs to communicate with a distant node, the "intermediate" nodes must pass through the information.

Multiple access
Multiple access networks are networks where multiple clients, multiple servers, or both are attempting to access the network simultaneously. Networks with one server and multiple clients are called "broadcast networks", "multicast networks", or "SIMO networks". "SIMO" stands for "Single Input Multiple Output". Networks with multiple clients and servers are known as "MIMO" or "Multiple Input Multiple Output" networks.

Data collisions
In a MIMO network, when multiple servers attempt to send data on a single channel at the same time, a data collision occurs. Because data typically consists of electric or electromagnetic radiation, a data collision causes both pieces of information to become unreadable. Clients on the network will either read meaningless data (garbage data) or will read no data at all. MIMO networks therefore will use some sort of collision avoidance or collision detection mechanisms to prevent data collision problems from affecting the network.

Networks with only one fixed sender per channel (point-to-point channels and SIMO channels) never have data collisions on the channel.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Communication Networks/Network Basics


text:
Talk:Contemporary Educational Psychology/Chapter 5: Students with Special Educational Needs

Chapter 5 is now complete in its basics (i.e. the running text is all there). It is still missing
 * 1) tables,
 * 2) figures,
 * 3) fully integrated cross-referencing to other pages, and
 * 4) other "pedagogy" features appropriate to the chapter.

KelvinLeeSeifert 15:24, 23 August 2007 (UTC)


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Communication Networks/Network Topologies

Topologies
The shape of a network, and the relationship between the nodes in that network is known as the network topology. The network topology determines, in large part, what kinds of functions the network can perform, and what the quality of the communication will be between nodes.

Star Topology
A star topology creates a network by arranging 2 or more host machines around a central hub. A variation of this topology, the star ring topology, is in common use today. The star topology is still regarded as one of the major network topologies of the networking world. A star topology is typically used in a broadcast or SIMO network, where a single information source communicates directly with multiple clients. An example of this is a radio station, where a single antenna transmits data directly to many radios. If there are n number of nodes in a star topology connection, the connecting lines between the nodes should be n - 1.

Tree Topology
A tree topology is so named because it resembles a binary tree structure from computer science. The tree has a root node, which forms the base of the network. The root node then communicates with a number of smaller nodes, and those in turn communicate with an even greater number of smaller nodes. A host that is a branch off from the main tree is called a leaf. If a leaf fails, its connection is isolated and the rest of the LAN can continue onwards.

An example of a tree topology network is the DNS system. DNS root servers connect to DNS regional servers, which connect to local DNS servers, which then connect with individual networks and computers. For your personal computer to talk to the root DNS server, it needs to send a request through the local DNS server, through the regional DNS server, and then to the root server. This is a good example of a tree topology.

Ring Topology
A ring topology (commonly known as a token ring topology) creates a network by arranging 2 or more hosts in a circle. Data is passed between hosts through a token. This token moves rapidly at all times throughout the ring in one direction. If a host desires to send data to another host, it will attach that data as well as a piece of data saying who the message is for to the token as it passes by. The other host will then see that the token has a message for it by scanning for destination MAC addresses that match its own. If the MAC addresses do match, the host will take the data and the message will be delivered. A variation of this topology, the star ring topology, is in common use today.

Mesh Topology
A mesh topology creates a network by ensuring that every host machine is connected to more than one other host machine on the local area network. This topology's main purpose is for fault tolerance, as opposed to a bus topology, where the entire LAN will go down if one host fails. In a mesh topology, as long as 2 machines with a working connection are still functioning, a LAN will still exist.

The mesh topology is still regarded as one of the major network topologies of the networking world.

Line Topology
This rare topology works by connecting every host to the host located to the right of it. Most networking professionals do not even regard this as an actual topology, as it is very expensive (due to its cabling requirements) and due to the fact that it is much more practical to connect the hosts on either end to form a ring topology, which is much cheaper and more efficient.

Bus Topology
A bus topology creates a network by connecting 2 or more hosts to a length of coaxial backbone cabling. In this topology, a terminator must be placed on the end of the backbone coaxial cabling. In Michael Meyer's Network textbook, he commonly compares this network to a series of pipes that water travels through. Think of the data as water; in this respect, the terminator must be placed in order to prevent the water from flowing out of the network.

Hybrid Topologies
A hybrid topology, which is what most networks implement today, uses a combination of multiple basic network topologies, usually by functioning as one topology logically while appearing as another physically. The most common hybrid topologies include star bus, and star ring.

Network Areas
Wireless networks do not have fixed topologies, so it doesn't make sense to talk about shape of these networks. Instead, other characteristics such as network size and node mobility are of primary importance.

Wireless networks and networking protocols can be divided up based on their intended range. Networks with smaller ranges have smaller power requirements and often have less noise to deal with. However, small networks are only able to communicate with small numbers of clients, compared with larger nodes. Increasing the number of clients in a network is often more useful, but more aggressive techniques need to be employed to prevent data collisions among multiple users in a large network.

Network Size Designations

 * Personal Area Network (PAN): Extremely small networks, often referred to as "piconets" that encompass an area around a single person. These networks, such as Bluetooth, have a range of only 1-5 meters, and tend to have very low power requirements, but also very low datarates.

 * Local Area Network (LAN): LAN networks can encompass a building such as a house or an office, or a single floor in a multi-level building. Common LAN networks are IEEE 802.11x networks, such as 802.11a, 802.11g, and 802.11n.

 * Metropolitan Area Network (MAN): These networks are designed to cover large municipal areas. Data protocols such as WiMAX (802.16) and Cellular 3G networks are MAN networks.

 * Wide Area Network (WAN): Wide-Area Networks are very similar to MAN, and the two are often used interchangeably. WiMAX is also considered a WAN protocol. Television and Radio broadcasts are frequently also considered MAN and WAN systems.

 * Regional Area Network (RAN): Large regional area networks are used to communicate with nodes over very large areas. Examples of RAN are satellite broadcast media, and IEEE 802.22.

 * Sensor Area Networks: These networks are low-datarate networks primarily used for embedded computer systems and wireless sensor systems. Protocols such as Zigbee (IEEE 802.15.4) and RFID fall into this category.


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Communication Networks/Cellular Networks

Signal Overlapping
Signals need to be separated in either time, space, or frequency to prevent multiple transmissions from overlapping and interfering with one another. FDMA and TDMA techniques attempt to separate transmissions into different frequency bands and time slices, respectively. These systems allow multiple users in a single area to communicate without data collisions.

However, networks can also be physically separated by space to prevent data collisions. In such cases, users can communicate at the same time on the same channel, so long as they are in different networks in different places.

Cellular networks are a method for breaking large networks into smaller groups called "cells". Each cell has different frequency characteristics. This means that frequencies can be reused by non-adjacent cells without causing interference.

Modeling Cells
Cells are typically modeled as regular hexagons. Regular hexagons have equidistant center between all adjacent cells. To avoid frequencies being used by adjacent cells, all cells don't share the same frequencies. If each cell used unique frequencies, then there wouldn't be enough frequencies to implement a large network. To get around this, frequency reuse is used to group cells into a pattern that within their group they don't share frequencies. This pattern is tessellated to fill out the area of service. The number of cells in a group is called the reuse factor. Common reuse factors include: 1, 3, 4, 7, 9, 12, 13, 16, 19, and 21.

In these hexagons, only four frequency bands are required to provide non-overlapping service to the entire network.

Network Expansion
As the demand increases, there are multiple ways in which the capacity of the network can be expanded.

Sub-Cells
Sub-cell techniques involve dividing an existing hexagonal cell into 7 smaller sub-cells. Smaller cells means that smaller base stations can be used, less transmit power is required, and more frequencies can be reused in a smaller area. Additionally, giving an entire frequency range to a smaller geographical area means that more people can be serviced in that area, and data throughput for the entire network can be increased.

Sectoring
Sectoring is similar to the sub-cell concept, except that instead of breaking a cell into smaller cells, a cell is broken up radially into "pie slices" called sectors. Each sector in a cell can reuse frequency ranges. Cells can be broken into 3 sector (120° divisions) and 6 sector (60° divisions) architectures.

Implementations
The reality of cellular networks is far different from the theoretical conception of them. In reality, base stations are not equidistant, and cells are not uniform size or shape. Because of the irregular size, shape, and placement of these cells, frequency orthogonality is more important, and networks often need to make use of many frequency ranges, instead of the theoretical minimum of three.


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User:LaraLove IMPERSONATOR/Sandbox

hello. --[[User:LaraLove|Lara[[User_talk:LaraLove|♥Love]]] 15:45, 23 August 2007 (UTC)
 * // test. --Lara [[User_talk:LaraLove|♥Love ] 15:46, 23 August 2007 (UTC)

title: User:LaraLove IMPERSONATOR/Sandbox


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User talk:LaraLove

Come introduce yourself at the new users page. If you have any questions, you can ask there or contact me personally. -- Herby talk thyme 15:52, 23 August 2007 (UTC)

Re:Move again
What do you want me to move again? where do you want me to move it? --Whiteknight (Page) (Talk) 13:51, 24 August 2007 (UTC)
 * Already taken care of, but thank you! Lara ♥Love 18:29, 24 August 2007 (UTC)

title: User talk:LaraLove


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Computer Systems Engineering/Probability

1.0 BASICS
An experiment, real or imagined, can be characterized by three properties. These are:

 * 1.		A set of outcomes
 * 2.		A grouping of these outcomes into classes
 * 3.		The relative frequency with which these classes occur.

For example, coin tossing is an experiment, the outcome of which is either heads or tails. One grouping of outcomes would be as heads (H) or tails (T). The relative frequency of heads would then be the number of heads in a large number of tosses:

(1)

If pairs of tosses are taken as the outcome of the experiment the set of outcomes would be HH, HT, TH and TT. These could be grouped into the three classes: 2 heads, 2 tails and 1 head and 1 tail. Assuming that the coin is fair the relative frequency of the class 1 head and 1 tail would be twice the other two.

In probability theory the “sample space”, denoted by S, corresponds to the set of outcomes, with each possible outcome being an element of S. An “event” corresponds to a class of outcomes and the “probability” is a measure of the relative frequency of the event. This can be interpreted as the fractional number of times the event occurs if the experiment is repeated many times:

(2)

Formally, the probability measure satisfies the properties:

*1.   For any event A, 0≤P(A)≤1 *2.	P(S) = 1 *3.	If A and B are mutually exclusive events then P(A+B)=P(A)+P(B). (3)

A + B is the set of elements in the sample space that are included in either the event A or B or both. An event A can be described as

A = {ω: ω satisfies membership property for A}				(4)

where ω is a member of the sample space, ωєS. This is read: “A is the set ω such that ω satisfies membership property for A.” Similarly, introducing the set theoretic notation for the complement, union and intersection of events, let

AC	= {ω: ω not in A} 		= complement of A 	A + B	= {ω: ω in A or B or both} = union of A and B*					(5) A,B	= {ω: ω in both A and B} 		= intersection of A and B* 	Ø = SC	= null event = no sample points since all sample points are in S

 * In set theoretic notation both of the symbols “+” and “U” are used to denote the union of 2 sets. Similarly, the intersection is denoted by “,”, “∩”, “∙” or, sometimes by writing the symbols adjacent to each other. The symbols “+” and “∙” are suggestive of the arithmetic opera¬tions of addition and multiplication with which the set operations of union and intersection are analogous. However, they should not be confused. One applies to sets, the other to numbers.

These are illustrated using the Venn diagrams below. The points in the square represent the sample space, S and those in an enclosed loop an event.

In I note that

S = A + AC									(6)

and that points in AC and A are mutually exclusive. Hence using (3)

P(S)= P(AC + A) 								(7) = P(AC)+P(A)

But P(S) = 1, hence

P(AC) = 1 - P(A)							(8)

In IV points in A and B are not mutually exclusive. In this case

(9)

The last term in (9) is necessary since both of the first 2 terms include the points in A,B but we only want to count these points once in A+B,

Conditional Probabilities

If the event B happens the “conditional probability” that A also happens, P(A|B), (read: “probabiljty of A given B”) is defined as 										(10)

This gives the fraction of the points in B that are also in A. In effect, with knowledge of B we can create a new sample space containing only the points in B and then look for the relative frequency of the points in A that are in B,

A and B are said to be independent if

P(A,B)	= P(A) P(B)							(11)

Note that if A and B are independent then

(12)

implying that knowledge of B tells nothing about how often A occurs. As we noted in (5) and (6), A and AC cover S and are mutually exclusive:

A + AC = S								(13) A, AC = Ø

Thus

B = B,A + B, AC								(14)

which simply states that every point in B is also in either A or AC. Then by (3)

P(B) 	= P(B,A + B, AC)						(15) = P(B,A) + P(B, AC)

By (10)

P(B,A) = P(B|A) P(A)							(16)

and

P(B,AC) = P(B|AC) P(AC)							(17)

Hence

P(B) = P(B|A) P(A) + P(B|AC) P(AC)					(18)

If the events Ai, i = 1,2…n are mutually exclusive and exhaustive, i.e.

A1 + A2 +… An = S							(19) Ai,Aj = Ø for all i ≠ j

then (15) and (18) can be written more generally as

(20)

and

(21)

This is the “law of total probability.” Another useful relation which follows from (10) is “Baye’s Law”:

(22)

However, by (18)

P(B) = P(B|A)P(A) + P(B|AC)P(AC)					(23)

and thus

(24)

Thus if we know the probability of event A, P(A), and the effect of A on the probability of B, P(B|A), the effect of B on the probability of A, P(A|B), can be calculated.

An Example

Baye’s Law can have some nonintuitive consequences in component testing.

Suppose that we have a way of testing memory chips. If the chip is bad (B) the test indicates bad (T) 95% of the time:

P(T|B) = .95								(25)

If the chips is good (BC) the test indicates good (TC) 95% of the time

P(TC|BC) = .95								(26)

Also assume that 1% of the chips are bad:

P(B) = .01								(27)

What percent of the chips which test bad really are bad? i.e., What is P(B|T)? Applying (24) we have

(28)

By (8)

P(BC) = 1 – P(B) = .99 P(T| BC) = 1 – P(TC|BC) = .05	 					(29)

Thus (30)

Also the probability that a chip which tests good, is good is 						 				(31)

and by (8)

P(TC|B) = 1 - P(T|B) = .05					(32)

Thus

(33)

Thus almost all of the chips that test good, are good, but only 16% of the chips that test bad are really defective. The test is not as discriminating as we might wish.

Combinations and Permutations

N distinguishable objects can be ordered (permuted) in N! different ways. This is easily shown by observing that any of the N objects can be put in the first position; any the remaining n-1 objects in the second position; and so on until only 1 object can be put in the last position.

More generally, a set of r objects can be selected from the set of N objects in N(N—1) (N—2) ... (N—r+1) = N! / (N—r)! different ways. This is sampling without replacement. If r =N, there are N! sets and each set is simply an ordering of the N objects.

Once selected, the r objects in the set can be ordered in r! different ways without changing the composition of the set. Each ordering corresponds to another of the N! / (N—r)! samplings. Thus, if only the objects selected and not their order is important, there are

different ways to select r objects from the set of N objects. This is called the combination of N objects taken r at a time and given the special notation

Note that for r = N,

and for r = 1,

The combination can also be thought of as the number of ways objects can be partitioned into groups of r objects and (N—r) objects respectively. This naturally leads to the extension that N objects can be Partitioned into k groups with ni objects in group i, i = 1,2,…k and N = Σni in

different ways.

2.0 RANDOM VARIABLES
A random variable is a variable whose value depends upon the outcome of the experiment. Thus a random variable is, in effect, a function assigning a numeric value to each event in the sample space, S. In practice the values assigned by the random variable to the events are chosen to have some physical meaning. For example, if we bet on the coin tossing experiment and win $l.00 for a head and lose $.50 for a tail the random variable X could be assigned the values (34) where ω is the outcome of the experiment.

Usually we are interested in the probability with which a random variable takes on a particular value:

P(X = x)								(35)

This is the sum of the relative frequency with which the members, ω, of the sample space for which X(ω) = x occurs. That is

P(X = x) = relative frequency for which X(ω) = x.			(36)

If the coin is fair (i.e. heads and tails are equally likely) in (34) then

P(X = 1) = 1/2 P(X = -.5) = 1/2							(37)

Another useful representation of a probability is the 'probability distribution function,'

(38)

This is also called the 'cumulative distribution function.' It is shown below for (34)

Note that since each point in S is mapped by the random variable onto the real line

P ( X ≤ -∞ ) = 0 P ( X ≤ ∞ ) = 1 P ( X ≤ x ) ≥ 0, for all x on the real line				(39)

Also for two points a and b on the real line

P ( X ≤ b) – P (X ≤ a ) = P ( a < X ≤ b ), for a < b			(40)

and

P ( X ≤ b) ≥ P (X ≤ a ), for a ≤ b					(41)

The random variable used to describe the coin tossing experiment can take on only a finite number of values ( 2 in this case: +1 and -0.5 ). This is called a discrete random variable. The random variable used to describe other experiments (e.g. the time between when two things happen) may, more appropriately, have a continuous range of values. This ‘continuous random variable’ has a continuous distribution function which we denote by 	F ( x ) = P ( X ≤ x )							(42)

As in the discrete case, F(x) is a non-decreasing function, and

0 ≤ F(x) ≤ 1, for all x.						(43)

A commonly encountered example of such a random variable is the exponentially distributed random variable

(44)

where λ < 0. This is shown below

For purposes of calculation, another function, the ‘probability density function,’ is often more convenient than the distribution function. Assuming that the derivative exists, this is defined as the derivative of the distribution function.

(45)

Since F(x) is non-decreasing, f(x) ≥ 0. Also by (45)

(46)

and

1 = F(∞) =								(47)

and

P ( a ≤ x ≤ b ) = F ( b ) – F ( a ) = (48)

Thus f ( x ) is a function which, when integrated over an interval, gives the probability that the random variable X lies in that interval.

Note that by (47) the area under the curve defined by f ( x ) is 1. Thus letting Δx be a small interval

f ( x ) Δx

is a rectangle of height f ( x ) and width Δx. Then f ( x ) Δx is approximately the amount of area under the curve of f ( x ) in the range of x to x + Δx

In the limit as Δx goes to zero ( denoted by dx: lim Δx  0 Δx = dx ) this approximation becomes exact. Thus it is often useful to think of f ( x ) dx as being the probability that X ‘equals’ x: 		f(x)dx = P(X ‘=’ x)						(49)

Strictly speaking it is the probability that X lies in a very small interval about the point x.

In modeling computer systems we are often interested in things such as the number of jobs in the system, waiting times and service requirements which can have only non-negative values. The random variables used to describe these quantities can have only non-negative values:

F(x) = P(X ≤ x) = 0, for x < 0						(50)

and this often makes the mathematics for dealing with them slightly simpler. In what follows we will assume that the random variables are non-negative but this can be easily extended to the more general case.

The exponentially distributed random variable (44) is a non-negative random variable. Its derivative is defined everywhere for x ≥ 0 as

= λe-λx									(51)

Expected Value

Although the probability distribution function describes the composite behavior of a large number of experiments it is generally too complex to be useful for comparing the results of alternative experiments. What is needed is a single number, a ‘figure of merit,’ which represents the outcome of the experiment. This is provided by the ‘expected value,’ ‘average value,’ or ‘mean’ (the three terms are synonymous) of the random variable. If X is a random variable then the notations E(X) and

are both used to represent its expected value. It is defined as the sum of the products of the value of the random variable and how often the experiment gives this result. For the discrete case this is

(52)

and in the continuous case

(53)

In the important case where the random variable is integer valued, (52) becomes

(54)

Note that this can be rewritten as

(55)

The sum of the terms in each column is kP(N = k), where k = 1, 2, … is the column. But the first row of (55) is simply the probability that N > 0, the second row that N > 1, and so on. Thus we can also write

(56)

Putting this in terms of the distribution function (38) we have

P ( N > k ) = 1 – P ( N ≤ k )						(57)

giving

(58)

Since the distribution function P ( N ≤ k ) can often be measured or estimated more easily than the density P ( N = k ), (58) gives a convenient way of calculating the average value of a random variable.

A similar result holds in the continuous case

(59)

This is easily shown by integrating (59) by parts:

(60)

Recalling that F ( ∞ ) = 1 and that

(61)

this reduces to

(62)

Since every random variable is associated with a number they can be operated on numerically (added, multiplied, etc.) and have arbitrary functions defined on them just like ordinary numbers. Let g(X) be a function defined on the random variable X. The definition of expected value (52, 53) can be extended to give the expected value of g(X): E(g(X))

E(g(X)) = 								(63)

if X is discrete or

E(g(X)) = 								(64)

in the continuous case.

The expected value of the sum of two random variables X and Y is

E ( X + Y ) = 								(65)

Using (16) we note that

P ( X=x, Y=y ) = P ( X=x / Y=y ) P ( Y=y )				(66)

and also

P (X=x, Y=y ) = P ( Y=y, X=x ) = P (Y=y / X=x ) P ( X=x )		(67)

Hence E ( X + Y ) = 								(68)

Now

(69a)

and

(69b)

hence

E ( X+Y ) = E ( X ) + E ( Y )						(70)

Also, if X and Y are independent

E( X,Y ) = 								(71)

since X and Y are independent. Thus

E ( X,Y ) = 	= E ( X ) E ( Y )					(72)

The results, ( 70 and 72 ), also apply when X and Y are continuous random variables.

Recall from (21) that

P (X=xi) = 								(73)

and by definition, (52)

E(X) = 									(74)

Hence

E (X) = 								(75)

By analogy with (52) the second sum in (75) is defined as the conditional expected value of X given Y=yj. This is usually written as E(X/Y):

E(X/Y) = E(X/ Y=yj) = 							(76)

Thus (75) is

E(X) =									(77)

but this is just the expected value of E(X/Y).

Hence

E(X) = E( E(X/Y) )							(78)

Again, this is also true if X is a continuous random variable.

Variance

As we noted earlier, the area under the density function is 1. If this “area” were cut out and placed on a pivot the expected value is the point at which it would balance.

Because of this relation with mechanics the expected value is often called the first moment of the random variable.

A second figure of merit which is also useful in describing a random variable is its “second moment” defined as

E (X2) = 							(79)

for the discrete case and

E (X2) = 							(80)

for the continuous case. Note that it is the expected value of the square of the random variable.

Instead of using the second moment directly, we usually are more interested in finding the “second moment about the mean” or “second central moment.” For the discrete case this is 								 		(81)

Recalling that the first sum is the second moment, (79), the second is the mean, (52), and the third by definition, (3), must be 1 this becomes

(82)

Similarly, for the continuous case (83)

The second central moment provides a measure of how closely the values of the random variable are grouped about the mean. For example, if the random variable can have only one value, α then

P(X=x) =	1 for x= α						(84) 0 for x≠ α

and

(85)

and

(86)

From which we see that, by (82),

(87)

For the exponentially distributed random variable mentioned earlier, (44, 51)

(88)

and

(89)

Hence

(90)

The second central moment in effect tells how much variation there is in the random variable. Appropriately enough, it is usually called the “variance” of the random variable, Var(X), and given by the symbol σ2:

(91)

Note that since σ2 is the expected value of the square of a random variable it is always positive.

Also, the standard deviation of the random variable, represented by the symbol σ, is defined as the square root of the variance:

(92)

Note that this has the same units of measure as both the random variable and the mean.

Although the variance and standard deviation provide a measure of the amount of variation to expect in the values of a random variable, a given amount of variation is usually less important if the random variable has a large mean than if it is small. The “coefficient of variation,” C, gives a way of expressing the amount of variation in relation to the mean value of the random variable. It is defined as

(93)

Note that for the deterministic random variable (84, 87) σ = σ2 = 0 and thus C = 0									(94)

For the exponential random variable (44, 90)

(95)

and hence using (88) and (89) in (93)

(96)

The Third Central Moment

The third central moment, M3, is defined as

and

for the discrete and continuous cases respectively. This gives a measure of the symmetry of the distribution.

For M3 = 0 the distribution is symmetrical. For M3 > 0 it is positively skewed, and for M3 < 0 it is negatively skewed. This is illustrated below.

The Fourth Central Moment

The fourth central moment, M4, defined as

and

for the discrete and continuous case respectively, measures the flatness or peakedness of the distribution. It is a somewhat more sensitive measure of the spread of the distribution than the Variance.

The figure below shows distributions having the same Variance, σ2 = 1, and M4 > 3, M4 = 3, and M4 < 3. For M4 > 3 the distribution is “tall and thin;” for M4 < 3 it is “flat” and for M4 = 3 it is “medium.”

REFERENCE
 * 1.	Kleinrock, Leonard, Queueing Systems Volume 1: Theory. John Wiley, NY, 1975.


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User talk:Anthony harper

Come introduce yourself at the new users page. If you have any questions, you can ask there or contact me personally. Mattb112885 (talk to me) 15:55, 23 August 2007 (UTC)

Image copyright problems
Thanks for uploading image(s) to Wikibooks. The Wikimedia Foundation is very careful about what Wikibooks includes because of copyright law, and requires that we maintain a strict copyright policy. Some or all of your uploaded files may soon be deleted unless we can determine the copyright holder and status. The copyright holder is usually the creator, the creator's employer, or the last person who was transferred ownership rights. Please take the time to read Media to learn more about what copyright information is required to satisfy our requirements and remember to include this important information for every file that you upload in the future as well. If you have any questions, feel free to contact me, or ask another Wikibookian at the help desk.

To find the files in question, use (unlicensed|untagged)

Thanks! '''– MBA ( Bot talk | Mike talk | owner | block ) 01:19, 21 September 2007 (UTC)

 * This is an automated message. Please ignore it if you've already provided license information for all your uploads.

title: User talk:Anthony harper


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CAT-Tools/STAR Transit

History

Transit is the integrated computer assisted translation environment developed by the STAR Group. Its beginnings date back to the year 1986. In 1991, Transit 1.0 (a 32 bit DOS version) is one of the first translator-dedicated workstations to appear. It already featured the modules that most of today's CAT tools have incorporated: A proprietary translation editor with separate but synchronized windows for source and target language and tag protection, a translation memory engine, a terminology management component and project management features. Transit 2.0, the first version for MS Windows appeared in 1994. Further features were added, network compatibility, enhanced usability and stability and more source file filters. In 1996, with version 2.6, the fuzzy match engine was introduced. The last 16 bit Windows version was the 2.7. The previous version, Transit XV, was launched in 2001.

The current version of Transit, 'Transit NXT', has been on the market since 2008. It is the second most popular CAT tool in many countries in Europe but less well known outside Europe. A key difference between Transit and most other CAT tools is that it does not generate one database full of disjointed reference segments but retains the documents in its own format from which translations are created. Thus, it is always possible in Transit to call up the exact context of a reference segment "hit". Because it does not use databases for its reference segments, it is possible to switch the direction of translation "live" at any time without having to export an existing translation memory (TM) and reimport it in the oppositre direction. Thus, the source and target languages are always at the same level of revision. A further key feature of Transit is the integrated dictionary window. Unlike some CAT tolls, this is not a feature that is relegated to the bottom of the priorities list but is a core feature, offering quick and easy term entry and the option of displaying graphics to illustrate terms as one works on a translation.

A number of CAT tools of the latest generation, including Transit, offer a formatted PDF or HTML view of the source text so a translator can see instantly whether a segment is body text, a heading, table header etc.

title: CAT-Tools/STAR Transit


text:
User talk:Kirsten Dunst

Come introduce yourself at the new users page. If you have any questions, you can ask there or contact me personally. -- Herby talk thyme 16:20, 23 August 2007 (UTC)

Project scope
Hi - please do look at the links above. This is a project for textbooks and as such the page you created was outside our scope and has been deleted. Thanks -- Herby talk thyme 16:20, 23 August 2007 (UTC)

title: User talk:Kirsten Dunst


text:
Talk:Making an Island/Construction Guides

If the island is placed in ocean, won't the saltwater kill the plants- destroying thier ability to hold stuff with their now rotting roots? I suppose the island could be made INCREDIBLY THICK so that the plants on the bottom would die and form a buffer to the ones on top.


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XForms/Repeat filter

Motivation
You want to dynamically display a list of items that match an input field as you type. This is character-by-character incremental filtering of possible options. The difference between this and other "suggest" options is that the list of possible options can be stored in an instance.

Method
We will put all of the possible choices inside of a xf:repeat statement. When the user types in the input field we will narrow down the choices using an XPath expression in the repeat xf:nodeset attribute. The XPath expression will only match items that begin with specific characters in the xf:input field.

Link to working XForms application
Repeat Filter

Sample Program
       Starts with filter:

  Select   </xf:action> </xf:trigger> <xf:output ref="title" /> </xf:repeat> <xf:output ref="instance('selected-data')/item"> <xf:label>Selected: </xf:label> </xf:output>

Discussion
The most challenging part of this example is the value attribute of the setvalue element:

We are setting the item of the selected-data instance:

We need to set it to the selected value - but the 2nd part -  - is the numeric index of the selected item in the filtered list. This is why we 1st have to filter the list and 2nd choose the right index out of the filtered list.

Just like in the restriction of the nodeset attribute of the repeat we are re-running the XPath expression and getting all of the items that start with the text in the filter.

Note that this is exactly the same expression as in the repeat nodeset attribute.

This list is additionally constrained with the position of the selected item on the data-list:

We are really doing consecutive filters on two sets of data. The first generates the same list as the search. The second uses the item selected to select the correct item.

Attribution
This example was originally posted on the mozilla XForms developer group by Chris Sw... on Aug 1st of 2007. A bug was found and fixed by Sivaram Arabandi.

title: XForms/Repeat filter


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Wikibooks talk:Policies and guidelines/Vote/Deletion Policy

Stewards
Hi guys,

I saw this: "Goes over the dos and don'ts of administrator actions regarding the deletion of content. These are mainly guidelines to administrator behavior, but can be useful to point at when having a serious dispute with administrators or going before stewards and an arbitration board.". Could someone please explain why the stewards are mentioned here? Stewards do not provide arbitration. Stewards are elected by the wikimedia community to perform administrative tasks which have been decided by the community first. They may have a few buttons, but certainly no mandate to be an arbitration committee of any kind. Thanks for clearifying this in your policy/guideline. Effeietsanders 19:18, 23 August 2007 (UTC)

 * Stewards aren't mentioned in the actual policy. This is an old vote page that was meant to summarize the page's goals and is most likely quite out of date. This is not an issue. Please respond on my talk page if you have any other questions. Thanks. -within focus 03:06, 24 August 2007 (UTC)

Recieved?
Shouldn't "recieved" in the introduction be spelled received? 72.218.194.210 (talk) 19:54, 31 May 2008 (UTC)


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Social and Cultural Foundations of American Education/Special Needs/Autism

This quote from Dr. O. Ivar Lovaas is especially suitable when discussing the treatment of individuals with Autism Spectrum Disorders (ASDs). His opinion is an expert one. Lovaas is known as one of the fathers of Applied Behavior Analysis, a treatment that demonstrates how teaching can modify the behavior of children on the autism spectrum. According to the Centers for Disease Control (CDC), “Many people with ASDs … have unusual ways of learning, paying attention, or reacting to different sensations. The thinking and learning abilities of people with ASDs can vary – from gifted to severely challenged.” How do we teach children with such a wide array of learning abilities? This currently serves as something of an obstacle for educators of children with a disorder on the Autism Spectrum... one that they are striving to overcome.

The Idea of a Spectrum
Autism, a disorder that affects thought, perception, and attention, can encompass a continuum of symptoms. Because the lines between the symptoms can often become blurred, it is necessary to place the disorders that vary in severity onto a spectrum. The Autistic Spectrum Disorders Fact Sheet on www.autism-help.org states that the “idea of a spectrum is that instead of trying to 'box' individuals into a specific disorder, they are seen as part of a spectrum: from the severe end where a child may have a profound intellectual disability, never communicate, and need full-time care, to a child who will experience some difficulties but be able to attend regular schooling and go on to employment, relationships, and the hallmarks of a typical lifestyle.”

Symptoms of a Disorder on the Spectrum
The DSM-IV, the diagnostic manual used to classify disabilities, categorizes autistic disorder under the Pervasive Developmental Disorders. Autism Spectrum Disorders are developmental disabilities that emerge before the age of three. In a child on the autism spectrum, deficits will be noticeable in their social interactions and their communication skills. The flawed social interactions could range from poor eye contact to aversion to human contact. Some examples of communication deficits are speech delay and echolalia, which is the repetition of words previously heard (ie television commercials). The children also exhibit repetitive behaviors or interests, like obsessions with certain objects and rocking or hand-flapping. Unusual reactions to certain sensory experiences, like loud noises or different textures, is another symptom of disorders on the spectrum.

Characterized by a pattern of impairments of varied severity in:
 * Autistic Disorder
 * 1) social impairment,
 * 2) language and communication, AND
 * 3) repetitive interests and activities.

Characterized by:
 * Asperger’s Syndrome
 * 1) average intelligence without a history of a delay in language development,
 * 2) noticeable impairment in social skills, and
 * 3) restrictive and repetitive interests.

Pervasive Disorder- Not Otherwise Specified (PDD-NOS) Often termed “a diagnosis of exclusion,” a diagnosis of PDD-NOS may be applied when a child “does not show all the symptoms required for a diagnosis of Autistic Disorder or if his or her symptoms are milder in nature (Stone 9).”

Source: Does My Child have Autism? Wendy L. Stone, Ph.D. with Theresa Foy DiGeronimo, M.Ed.

What are the Different Autism Spectrum Disorders?
The spectrum of Autistic disorders includes: Autistic Disorder, Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS, including atypical autism), and Asperger syndrome. Although they are characterized by similar symptoms, these disorders vary in severity, age of onset, and the exact nature of the symptoms. A diagnosis of a condition on this spectrum can, arguably, remain valid throughout a person’s lifetime.

What Causes ASDs, and Is There a Cure?
“What we know about the causes of autism, at this point, is all correlational, and many of the correlations are rather weak (Siegel 18).” As of the creation of this article, the exact causes of autism are still unknown. There have been inquiries into whether vaccinations have caused this massive upsurge in cases of autism, but there a lack of sufficient evidence to confirm or refute this claim. ASDs do not affect any one group in particular; race, ethnicity, or socioeconomic status does not adjust the chance of acquiring an autism spectrum disorder. However, it has been established that ASDs are four times more common in boys than in girls. There is also an increased prevalence in rates of autism for families with previously diagnosed autistic children, suggesting some genetic correlation.

Although there is no precise “cure” for an individual on the spectrum, various methods are being implemented in homes and schools to address the specific treatments of those with ASDs. These include alternative behavioral methods, speech/occupational/physical therapies, and dietary modifications. The gluten-casein free, or GCF, diet is the most popular. It consists of elimination of wheat and dairy products from the diet of individuals on the spectrum. The National Institute of Medical Health is currently performing a clinical trial that will determine the effects of the gluten-casein free diet on children with autism.

The Rise in Children with ASDs
The CDC, together with the American Academy of Pediatrics (AAP), issued an Autism A.L.A.R.M. and concluded that as many as 1 in 166 children have an ASD. In 2007, CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network published data indicating that 1 in 150 8-year-old children throughout America were on the autism spectrum.

The public schools in America are under pressure to implement innovative teaching methods to address the scope of challenging behaviors and learning difficulties, as more children are being diagnosed with autism. The amount of children with an autism classification in special education is rising at near-epidemic proportions. According to the CDC, the number of 6 to 17-year-old children classified as having an ASD in public special education programs escalated from 22,664 to 193,637 between the years of 1994 and 2004. They received this information from IDEA accounts. The Individuals with Disabilities Education Act (IDEA) decides how states and public agencies will provide early intervention, special education and related services to American children with disabilities. Their records from 2005 show that 6,109,569 children ages 6–21 received services through 13 of the categories in public special education programs. About 3% (193,637) of these were autistic children.

Definition of Education
Presently, education is the fundamental treatment for people with autism. The definition of education is "the fostering of acquisition of skills or knowledge-- including not only academic learning, but also socialization, language and communication, and reduction of behavior problems-- to assist a child to develop independence and personal responsibility (Lord, McGee 12)." The Surgeon General maintains that immediate, rigorous behavioral and educational intervention can actually help autistic children become capable of learning and develop their social skills.

Effective Instructional Programs
Common Elements of an Effective Treatment Program for Children with an ASD (Stone 113)
 * Early intervention, involving families in each phase of the assessment and educational processes
 * Customized goals based on information received from assessments
 * Concentration on the "core deficits" of autism: social skills, language and communication, imitation, and age-appropriate play
 * Structured, supportive teaching approach and predictable environment
 * Consistent monitoring and reevaluation of goals
 * Encourages students to take a broad view of skills learned, that they may apply them in alternative settings (generalization)
 * Takes initiative and uses positive approach, pertaining to behavior management
 * Offers students "opportunities for structured interactions with typically developing peers"
 * Prepares students for possible mainstreaming into regular ed classrooms, and/or transitioning to new learning environments

Individualized Education Plan
When a child who has been diagnosed with an ASD enters the school system, their parents should contact the local special education department and meet with an Individualized Educational Plan (IEP) team. The IDEA has determined that this team should consist of: the child's parents or caregivers; at least 1 of the child's regular education teachers; at least 1 special education teacher; a representative of the local educational agency; someone capable of interpreting the results of the evaluations, and how they affect the child's education; other individuals the parent or agency believe have valuable input regarding the child; and "whenever appropriate, the child with a disability." The goal of this meeting is to determine the individual educational needs of the ASD student. This should be done by distinguishing the child's areas of strength and determining his or her areas of challenge. The IEP should exist as the means "for planning and implementing [a]ppropriate educational objectives for children with autistic spectrum disorders [that] should be observable, measurable behaviors and skills ... [These goals] should be able to be accomplished within 1 year... Progress should be monitored frequently and objectives adjusted accordingly (Lord, McGee 218)."

Structured Teaching
Because individuals with autism process visual information more effortlessly than verbal information, the use of visual cues is a sensible method of instructing in the autism classroom. Autism consultant Susan Stokes' article Structured Teaching: Strategies for Supporting Students with Autism, addresses the primary components of Structured Teaching: 1) the physical structure of the classroom; 2) the use of visual schedules; and 3) the structured teaching method. She defines Structured Teaching as: "a system for organizing their environments, developing appropriate activities, and helping people with autism understand what is expected of them." It is imperative that the arrangement and subsequent organization of the students' physical environment is taken into account. According to Susan Stokes, "Physical structure provides environmental organization for people with autism. Clear physical and visual boundaries help the person to understand here each area begins and ends. The physical structure minimizes visual and auditory distractions."

Physical Structure: The classroom should be painted a muted color, and there should be minimal visual distractions (ie walls cluttered with posters). The designated areas in a classroom should have clear, definite boundaries. This can be achieved with furniture placement. The children should attain a better perception of their environment and allow them to become less dependent on adult direction.

Visual Schedules: Visual schedules focus on the ability of many children with ASDs to process visual information. It sequentially organizes the student's schedule in a visual timetable. This gives the student an idea of what is expected of them. For children with anxiety about transitions, the visual cues will allow them to predict what will come next. There should be a general class schedule, as well as an individual schedule for each student. This allows the student with alternative scheduling (ie: Speech Therapy, Occupational Therapy, Physical Therapy, Behavioral Counseling, etc.) a chance to visualize his or her personal schedule.

Teaching Method: Because all of the details that go into completing their work can overstimulate a child on the spectrum, it is best to isolate only those with significance to the task at hand. The use of visual instructions to organize the steps of the task, visual organization to present only the necessary materials in an organized fashion, and visual clarity to emphasize the details and minimize the distractions are critical components of the structured teaching method. These fundamental building blocks can potentially allow for an increase in the child's independence not only in school, but also at home and/or work (Stokes).

Curriculum Management
Keeping your curriculum varied to cover those students suffering from any form of Autism is a very challenging but very important part of teaching. Making your lesson plans varied allows for you, as a teacher, to incorporate more students into your classroom.There are a few tips that teachers can be sure to follow that will make any lesson plan more varied to help Autistic children learn in mainstream classrooms. For starters, using a whiteboard for organization helps Autistic children to see the information displayed clearly. Keeping the information on the board to a minimum and color coding the information helps the students greatly. Another way for helping students battling with Autism is with picture cards. Adding the visual aspect to learning helps the students to learn faster and better.

Physical Education with Autism
Research has shown that vigorous exercise decreases stereotypic behaviors, hyperactivity, aggression, self injury and destructiveness in individuals with Autism and those who are mentally disabled. Stereotypic behaviors and hyperactivity interfere with the educational process in the classroom. Parents, Teachers and Schools should include a rigorous exercise program in students Individualized Educational Plan (IEP). A vigorous workout typically consists of 20-30 minutes of aerobic exercise; a mild workout has little effect on behavior. Therefore, students do not get an adequate amount of exercise during recess to have an effect on behavior. To reduce stereotypic behavior problems in the classroom and at home, try an inexpensive and safe exercise program rather than expensive and harmful drugs.

Conclusion
When it comes to educating children with ASDs, the fundamental rule appears to be that there is no best method. There are several measures that can be taken, however, to ensure that a child gets the best treatment they can receive. This begins with instituting a team that will set a plan for the child, an IEP complete with educational and personal goals that should be able to be achieved within a school year. It continues with implementing an educational plan tailored for that particular student. Individualizing the plan by considering the advantages and disadvantages of alternative methods for the specific child seems to be the conscientious decision. The amount of energy and perseverance that must go into teaching children on the autism spectrum can seem overwhelming. However, the benefits of tailoring a child's education to suit their individuality are remarkable. The potential for attaining their goals and developing the capability to learn self-sufficiency is "there for the teaching."

Multiple Choice Questions
Click to reveal the answer.

Essay Question
Click to reveal sample responses.


text:
User:LaraLove

I contribute on the English Wikipedia under this same user name.

This account was originally created by an impersonator. User:Herbythyme informed me on my talk page on en.wiki. He then indef blocked the user. User:Whiteknight renamed the account, changed the password and emailed me the information.

Interwiki accounts
en.w | en.wn | en.wt | en.wq | meta | commons

title: User:LaraLove


text:
Social and Cultural Foundations of American Education/Hot Topics/Homework

A typical school day in the United States is six to six and half hours long. During this time, teachers are required to teach four to five core subjects, including math, English, science, and history. In addition, they must find time to include the fundamental supplementary subjects. These supplementary subjects include, but are not limited to, physical education, health, art, music, and foreign language. In these six hours, lunch and recess must also take place. Because of the large curriculum and the limited time, many teachers assign homework.

What is Homework?
Homework is work assigned to students, by teachers, to be completed outside of the school. “It is used as an instructional supplement to classroom teaching.” (6) Although it is not required, homework is typically counted as part of the students’ grade. “The U.S. is one of the few nations where teachers include homework scores as an element of course grades.” (2) Forms, objectives, and lengths of homework vary. A large debate surrounds the importance of homework and the time restraints it places on today’s students.

History of the Homework Debate
The debate over the importance of homework is not a new one. It has been debated since the late 1800s. Between the late 1800s and the mid 1900s some cities in the United States banned homework on the account that it was affecting the health of children; “many thought (homework) was an overemphasis on at-home drill and memorization”.(2) Children were spending so much time on schoolwork and homework that they were mentally and physically exhausted. However, in the 1950s and '60s homework loads began to increase. The government felt that the “United States was becoming less economically competitive” (2). A major event that sparked these notions was the Russians' launch of the Sputnik satellite (7). This increase of homework lasted until the 1970s, in which it once again made a drastic decline. In the 1980s the load once again begins to increase (2). This time it is due to the incompetence on international tests. In 2002, Congress passed the No Child Left Behind Act under President George W. Bush. Under this act, teachers and administrators are required to submit their school's achievements on state standardized test to the federal government. Failure to comply or to reach the goals set forth by the state leads to a range of consequences. The most severe consequence is the replacement of staff in those failing schools. According to the NCLB Act, all students must be proficient in math and reading by 2014 (2).

Types of Homework
Homework is assigned in a multitude of varieties. Some assignments include reading specific content, problems at the end of a chapter, worksheets, research papers, and creative projects. Teachers may assign daily homework in which the assignment is to be completed and turned in on the following school day. Alternatively, teachers may assign long-term assignments; giving the students a week or more to complete the assignment. Homework assignments can be used to reinforce lessons taught in class, or elaborate on briefly introduced material (2). In addition, homework assignments may be used to prepare the students for an upcoming lesson (5).

Purpose of Homework
“Different homework assignments serve different purposes, so it is important to consider the goal of each exercise.” (5) Some valid purposes of homework assignments include knowledge, comprehension, application, analysis, synthesis, and evaluation. (5) Homework assigned to reinforce lessons gives students the opportunity to practice newly acquired skills. They also help teachers assess the students’ understanding and comprehension of the lessons. Homework assigned to elaborate on newly introduced material requires students to take initiative and learn independently. This type of assignments also allows teachers to introduce more material throughout the school year. Homework assignments designed as preparation for upcoming lessons introduces the lesson to the students beforehand and therefore increases their ability to comprehend it. All of these reasons are intended to have a direct effect on students’ learning and academic performances. In addition to these academic lessons, homework results in positive non-academic lessons. Homework teaches the values of responsibility, good work-study habits, time management, initiative, and motivation. “Perhaps the most important advantage of homework is that it can enhance achievement by extending learning beyond the school day.” (8)

The Effects of Homework
Does the amount of homework assigned have an impact on the academic success of students? Unfortunately, there is no straightforward concrete answer. Research shows that homework affects students differently depending on their age and grade level. The effect of homework on academic success increases as age and grade levels increase. The National Education Association and the National Teacher Association endorse a 10 minute per grade rule of thumb (2). This rule of thumb suggests that first graders should be assigned approximately ten minutes of homework, second graders about twenty, and twelfth graders about two hours.

Elementary School
Although homework has the least effect on elementary aged students, research shows that the homework loads have increased in the elementary schools over the last decade (2). “Research shows little evidence that homework improves learning or school achievement for children in the early grades.” (2) Students at this age have a limited attention span and grasp of study skills. A vast amount of homework may actually inhibit their academic achievement; “it can be counter productive, children will show signs of fatigue and frustration”. (7) Homework, in moderation, is more important at this age level to foster good work-study habits and teach self-motivation and responsibility.

Middle School
Research is inconclusive on regards to the effects of homework on middle school students. However, research does show that middle school is the stage of school that our students began falling behind on an international level; “by middle school U.S. scores begin to fall (on international achievement tests)” (2).

High School
Homework has the most effect on the academic success of high school students. There is a correlation between homework and scores on achievement tests and overall grades. (6) Following the ten-minute rule of thumb, the optimal amount of homework for high school students is approximately two hours. The more the better does not apply after two hours. Each added hour doing homework shows a smaller pay off in achievement (6).

Too Much or Too Little
A major debate surrounds the effect and time restriction that homework has on school-aged children. Should homework be required? How much is too much? Critics against required homework argue that if students are assigned too much homework it leaves no time for family, extra curricular activities, and play. “Research shows (these activities) are more highly correlated with cognitive development and achievement than is homework.”(2) Too much homework can lead to stress, sleep deprivation and even depression. An unreasonable amount of homework dims children’s love of learning and too much may “diminish its effectiveness or become counter productive”. (2) On the other side, critics that are for required homework argue that the schools are not assigning enough homework. “Mastering a subject or skill takes practice, and homework can provide that practice.” (5) Students have the weekends, holidays, and summer to play. The amount of time spent on academics, to include the length of school days and school years as well as time spent on homework, does not compare with other industrialized countries, such as Asia and Europe. (2) Supporters of homework argue that homework adds to study time, and study time is the chief determinant of how much students learn. (2)

Importance of the Type of Homework Assigned
The type of homework that a teacher assigns can have a lot to do with its effectiveness. “Even more important than how much homework is what kind.” (2) If students are required to complete repetitive, long, ill thought out assignments, the knowledge they gain by doing so is minimal (8). For example, if there are 40 math problems assigned focusing on the same material, a student that knows the material may feel that it is repetitive and pointless. On the other hand, a student that is having a hard time with the material may get frustrated and disengaged. An approach taken by many teachers to avoid these issues is to use the five-problem rule recommended by the U.S. Department of Education (2). This rule suggests that teachers should not assign more than five problems of any given content. Five problems are enough to assess weather a student comprehends the material or not. Furthermore, “if a child who did not get the right idea in class slogs through thirty problems, she is just cementing the wrong method in her brain” (2).

Teachers must carefully plan and assign homework in a way that maximizes the potential for student success (2). Not all students learn the same way. Students may be visual, verbal, or logical learners. Teachers need to be aware of the different learning strengths of their students and vary the types of homework they assign to include all types of learning styles. In addition, assignments must be realistic in length and difficulty (8). First graders should not be expected to learn twenty-five seven-letter words for a spelling test. Teachers need to take in to account their students logical and mental capabilities. Teachers should limit assignments to important and thoughtful ones (2). They should not assign homework just because it is expected by the parents and/or students. Generally, students complete their assignments because of expectations, as opposed to the educational gain they will receive by doing so. Keeping this in mind, teachers should assign homework that will keep the students interested while expanding their knowledge.

Conclusion
Homework is a hot-button topic in education. Some view homework as a needless waste of time and effort, and source of tremendous stress for students; while, others view it as an excellent study and review tool. As a middle school teacher, I see it as a way for my students to hone the information they learned in class and also continually spiral back to retain information learned previously. Also, it can be used as a way to introduce new topics and peak interest in a student. It is a valuable resource one can use to their advantage. However, it should not be a determining factor in a student’s grade point or average, as it is merely a tool and not a fundamental aspect of any course; the heart of the material should be assessed and covered in class. In fact, many teachers refuse to even assign homework as it is understood that students rarely complete it or put great effort into it. Whatever one’s feeling regarding homework, there is a definite ‘best’ method one can employ to reap the full benefits of homework. As pointed out by the National Education Association, “ensuring students’ success is a shared responsibility” (NEA, 2006, p. 2). That is, as parents and educators, we should be utilizing every avenue available to us to assist our students in their journey for academic success. As the achievement gap becomes a gorge the world grows ever more competitive and unforgiving. So, what can we do to make homework work? First, we can be prepared. Secondly, be on the same page as the instructor or teacher—understand their policy. Thirdly, be accessible and willing to model your expectations. Also, utilize all of your resources and stay in touch. Finally, foster learning even outside of school. (NEA, 2006, p. 1-3).

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Social and Cultural Foundations of American Education/Hot Topics/Year-Round Schooling

The school system was established when the United States was mostly an agrarian nation, basing it on a ten-month system. The reason for this system was because children were often needed at home to work in the fields during the summer months. Times changed and many people felt the need to do away with the ‘antiquated’ system and move toward year-round education. In 1904, the year-round educational system was implemented for the purpose of solving the problem of overcrowded schools. The trend ended with the advent of World War II, beginning again in 1967. Today, the system is used to solve many other problems the educational system has been faced with. There are 3,181 schools involving 1,118,608 students using alternative calendars.

With the mounting dissatisfaction of U.S. elementary and secondary education, there is much interest in year-round schooling. Repeated studies show that American high school students’ scores are well below students from other advanced countries, especially on core academic subjects, such as mathematics and history. These students typically have longer and more instructional days than most American schools. For example, German, French, and Japanese children spend more than double the time studying basic subjects such as math, reading, history, and science than do American children (Gregory, 1994). Although only a small percentage of school-age children attend year-round schools, the numbers are steadily growing; however, there is still much controversy over the positive aspects of year-round education versus the traditional school year. The term “year-round” is actually misleading, with other more descriptive terms being “continuous learning,” “all-seasons learning” and “four-seasons school.” The purpose of the year-round school is not to be used as an alternative curriculum for learning but as “a reorganization of the school calendar into instructional blocks and vacations distributed across the calendar year to ensure continuous learning” as defined by Quinlan, George and Emmett (1987).

Both traditional and year-round students attend school approximately 180 days per calendar year. The difference between traditional and year-round students is that traditional students attend for approximately nine and one-half months with a two and one-half months vacation, while year-round students attend school for twelve months, with shorter breaks during the school year. There are different options that schools can use for the year-round schedule, such as the single-track and multi-track pattern. The most common pattern for year-round student vacations/breaks is called the “60/20 calendar,” meaning that the students attend school for 60 days followed by a 20-day break, occurring three times during the school year. According to Eric Stone, Principal of Merrimack Elementary School, “Hampton City Schools have tweaked its balanced calendar (which is how he referred to the year-round schedule) to include two 9-day intersessions, one in the fall and the other in the spring, each followed by a 7-day vacation.” Mr. Stone expressed that he felt other schools have adopted a year-round calendar strictly as a way to address the need for physical space. He gave me the example of some year-round schools in California where students and teachers pack up their supplies at the end of the school year and a whole new group of students and teachers occupy the same classroom the next day.

“Summer Brain Drain” and the Achievement Gap
According to Duke University psychology professor, Dr. Harris Cooper, the average student test score in a traditional school is one month lower when they return in the fall than before their summer break. The lack of retention is most evident in math and reading skills. Information that is memorized such as math computations and spelling words carry the lowest level of retention and are therefore most likely to be damaged by the “summer brain drain.”

This summer retention problem is more pronounced in students with lower socio-economic status. Math retention suffers across the board because parents are less-likely to review math skills over the summer break. Students in higher socio-economic classes are more likely to retain their reading level over the summer month and in some cases improve a few levels. This is due to the likelihood that their parents are more likely to see reading as an important skill and encourage their children to read over the long summer break. According to Ron Fairchild, Executive Director of the Center for Summer Learning at Johns Hopkins University, by the fifth grade the reading level of low-income students at traditional schools are on average two years behind that of their high-income peers.

Pros
The issue of year-round education has many advantages, with information retention at the top of the list. Long summer breaks encourage students to forget knowledge they have learned the previous year, forcing teachers to spend weeks reviewing what was taught the previous year, which is time that could be used teaching students new information. A less interrupted flow of instruction, along with remedial reviews offered during breaks, is advantageous even to the slowest learner. For instance, Brenda Teeter, a science teacher who is participating in year-round schooling made the observation that “the year-round program is particularly good for at-risk students because they don’t have that long summer to forget what they struggled so hard to learn” (Gregory, 1994). With better information retention, reducing the number of students retained in grade and allowing more students to excel in their studies, more students are obtaining a high school diploma rather than the traditional student drop-outs due to the frustration of not being able to retain information throughout the summer and getting further behind in school work the following year. A great way that the education system has been able to measure the success of year-round schooling is by looking at test scores of which many of the results have been positive. One school district in Texas, Socorro, was known to have “some of the lowest test scores in the county” when they were using the traditional school calendar (Gregory). After Socorro schools switched to the year-round schooling schedule, however, the students ‘outscored the state average on the Texas Assessment of Academic Skills’ (Gregory).Another factor in less school drop outs is that fact that with more breaks, students tend to be absent less often, aiding in better grades. Students with learning disabilities that are worked with year-round are aided by this program because shorter breaks makes going back to school for them less of an ordeal and also allows them to progress increasingly faster than they would on a traditional schedule. Another advantage is cost-effectiveness, to both the school system and the parents. By using the single- or multi-track system, schools do not lay empty for three months, but are being put to use all year, accommodating more students instead of having to build more schools. With the schools being in use all the time, there is less school vandalism. Studies show that most of school vandalism is caused by students with too much free time during summer break who get bored, turning to vandalism and other crimes. Since the majority of American families have both parents working outside the home, students in year-round schools are not left by themselves as often. Another positive factor for parents is that they have less child-care expenses with the children in school year round, with many have the option of putting younger children in programs during intersessions at a cost less than day care. Year-round education also benefits teachers’ attitude because they are less likely to be stressed or burned out with more frequent breaks. They can also use the time available in between sessions to plan new and interesting lesson plans. One teacher stated that she was sold on it because she was able to catch her breath and “come back and hit it hard again.”

Cons
In addition to the perceived benefits of year-round education, research also shows perceived drawbacks. Such concerns include issues such as the cost of utility bills due to the constant use of school buildings, especially during the summer months when air conditioning can be very costly. Not to mention older schools that do not even have air conditioning. Many parents are concerned that without the traditional summer breaks, family vacations will become a thing of the past. Also, students are unable to attend summer camp or work summer jobs earning extra money. In an interview with Mrs. Michelle Koontz, a teacher at Woodside High School, she expressed that she feels “…in High School it is good for the students to be off all summer so that they can get jobs and learn skills.” She feels that summer jobs help them learn the responsibility of holding a job and paying for their own things. Teachers also encounter such challenges as organizational issues, especially those in multi-track YRE because four different teachers might be required to share three classrooms throughout the year. Thus, packing up their materials and moving out of their classrooms for the 3-week break and into a different classroom upon their return. In the overall scenario, moving day would include rolling carts, storage space and available custodial assistance (Worthen & Zsiray, 1994). There is a unanimous concern by teachers in multi-track schools regarding moving and lost materials (Quinlan, George & Emmett, 1978). Having students in school year round doesn't keep them from forgetting what they have learned. "Students are going to forget information whether they are out of school for three weeks or 10. Therefore, teachers will be performing four beginning of the year reviews instead of just one" (Kelly, Melissa).

Cons to Pros
The No Child Left Behind's costs are not only reflecting the funding but also on the instructional time, staff time, administrative time as well as human resources time. Several school divisions refer to opportunity costs as time that could have been used for other sources within the curriculum. Although, instead of the available time for opportunities of enhancing a child, the time was spent on some form of testing which can be distinguished into three categories: preparation, test administration, and loss of services and instructional time.

The preparation of testing is complex and often consists of multiple school staff employees to complete the tedious tasks. For example, the testing material arrives at a school district in October and before any testing begins, each test booklet must have the accurate number of data labels as well as test booklets. Prior to and after the testing, the three versions of the test for each grade level must be stored in a confined and secured area. When all testing has been completed, the testing materials are to be returned to the school board office (central office), properly packed, and shipped to be scored. Among the entire staff, guidance counselors along with secretaries spend the majority of their time in preparation for the logistics. The average amount of time spent to complete the tasks range between ninety and ninety five hours.

Test administration has lead to difficulties with the scheduling. “Paraprofessionals spent a per-district average of one hundred and two hours assisting teachers with testing. Teachers spent a per-district average of nine hundred and seventy six hours administering tests. Administrators’ spent a per-district average of sixty two hours in various testing tasks” (Chmelynski, 2006, p. 44). The testing criteria is at times so demanding and intense in that substitutes are often required to administer the students during testing. Often school divisions have to adjust the schedules in order to accommodate the testing.There is a loss of services for the disadvantaged students. For example, the special needs students in actuality need the instruction more so than the advantaged students. “One huge consequence is that the testing shifts the focus, for at least a month, from learning to testing. This plays out in many ways from the time actually testing to loss of guidance and reading specialist support to loss of administrative support”( Chmelynski, 2006, p. 45).

Single and Multi-tracking
Single Track provides a balanced calendar for a more continuous period of instruction. Students and all school personnel follow the same instructional and vacation schedule. Single-track does not reduce class size, nor does it allow a school to accommodate more students. The long summer vacation is shortened with additional vacation days distributed throughout the school year into periods called "intersessions." Intersessions allow time for remediation and enrichment throughout the school year. The most common types of single-track calendars are 45–15, 60-20 and 90–30.

Multi-Track is used primarily to alleviate overcrowding, although it also incorporates the educational values of single-track YRE, including intersessions. It was designed specifically for schools with a shortage of classroom space. Multi-track is used to avoid double sessions, building new schools and temporary structures. It not only saves on capital construction costs, but on the ongoing costs that are part of operating a new school. Multi-track divides students and teachers into groups, or tracks of approximately the same size. Each track is assigned its own schedule. Teachers and students assigned to a particular track follow the same schedule and are in school and on vacation at the same time. Multi-track creates a "school-within-a-school" concept Multi-track divides students and teachers into groups, or tracks of approximately the same size. Each track is assigned its own schedule. Example: implementing a four-track year-round calendar extends the capacity of a school by 33%. A school with the capacity of 750 students can accommodate 1,000 students, as only three tracks of 250 would be in school at the same time; there would always be one track on vacation or intersession every day of the school year. A five track model (60-15) allows for a 25% gain in capacity.

Teacher Benefits
Many year-round schools provide extra classes during their intersession breaks that students are offered but not required to attend. Timber Lane Elementary School in Fairfax County, Virginia provides classes in “diverse offerings ranging from academic topics as math to such hobbies and sports as gardening, photography, and soccer”(Haser 2003). Teachers are given the option to work during these periods. This part-time work provides some extra income as well as gives the teacher a chance to pursue something else that they are interested in. The flexible schedule that is provided by these intersessions also provides the accommodations to allow teachers who are on maternity leave to slowly enter back into the work force. A teacher was quoted saying “ I teach three intersessions a year and find the experience rewarding. I’m able to earn money, be with children, and use my skills as an ESL specialist. When I was pregnant, I thought about changing to a career in real estate while I stayed home, but the intersession teaching option has changed that. In another year, I think I’ll be ready to go back to teaching full-time.”(Haser 2003). On top of all these benefits teachers are also given the opportunity to take vacations during the off seasons, “Such as visiting Italy in October” when it is much cheaper. Also most teachers feel that this schedule makes our career one that is viewed as much more professional then the way in which people view the traditional scheduling (Haser 2003).

Student Benefits
Along with the teachers, the students also endure great benefits from year round schooling; even if though they might not agree. Studies have shown that when students attend school year round that they have a more continuous learning pattern. This helps the students remember things easier and it makes the need for review less necessary. By having a shorter vacation period students will not have to worry about forgetting lessons they were taught right before the break. Another great benefit is that during the break periods students are given the option to take classes over they might have failed. With this students are given the chance to retake a class with out having to wait until the next school year and falling behind all the other students. Now they are given the chance to keep up with their classmates if they are struggling in certain areas. Many people have also noticed an improvement in students overall school performance. By having shorter periods in school and out of school, it helps the students to stay motivated and excited about school. They are less stressed out and enjoy it more.

Conclusion
Year-round schools are clustered in certain regions and states according to Charles Ballinger, National Association for Year-Round Education's (NAYRE) executive director, who notes that “83 percent of our year-round schools currently are west of the Mississippi,” and that Eastern schools have been “far more resistant to change.” One explanation as to why year-round education is occupying only a tiny niche in American primary and secondary education is the negative attitude shared by many parents and educators. The fact is that 76 percent of year-round schools are in California, Florida and Texas, probably because these three states have experienced robust population growth in recent decades, causing severe school overcrowding. In today's world where there is constant change, year-round education seems to be a change in which many parents and educators are not willing to accept. Is this resistance justifiable or is fear of change a primary factor in the resistance of year-round education? Mr. Stone believes it is. He stated that “When families first come to register [for school], many panic and students cringe when they hear ‘Merrimack is a year-round school’.” Does it make sense to use an outdated schedule when we want the newest and the best in every other aspect of our lives? Although the year-round schedule may not be the answer to all educational problems, it certainly is an option to consider!

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User talk:LaraLove/Archive 1

''This account was created by an impersonator. Once this was realized, the user was indef blocked and I, the real LaraLove, assumed the account.''

Deletion nomination
I have removed this as a misguided nomination. The guide is an well established part of Wikibooks and believe me contains no spam - I am someone with strong views on that subject. Please contribute thoughtfully and carefully - thanks -- Herby talk thyme 15:52, 23 August 2007 (UTC)

Account
I believe this is an imposter account and have blocked it while I check details -- Herby talk thyme 16:01, 23 August 2007 (UTC)
 * I'm the actual LaraLove, which is proven by my responses on my talk page on the English Wikipedia. This account was not created by me. 75.183.122.31 16:17, 23 August 2007 (UTC)

And indef blocked -- Herby talk thyme 16:20, 23 August 2007 (UTC)

title: User talk:LaraLove/Archive 1