functions of data link layer in osi model
Tài liệu Module 7- Data Link Layer CCNA Exploration 4.0 pptx
Ngày tải lên :
22/12/2013, 13:17
... Overview
Upon completion of this chapter, you will be able to:
ã Explain the role of Data Link layer protocols in data transmission.
ã Describe how the Data Link layer prepares data for transmission ... Connecting Upper Layer Services to the Media
11
ã To support a wide variety of network functions, the Data Link layer is often divided into
two sublayers: an upper sublayer and an lower sublayer. ... consists of virtual connections between the
nodes of a network independent of their physical layout.
– These logical signal paths are defined by Data Link layer
protocols.
ã The Data Link layer...
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Hình ảnh Protocols in relation to the OSI model.doc
Ngày tải lên :
24/08/2012, 21:11
... Session
Network
Data link
Physical
zone 1
zone 2
H2:H.323 Protocols in relation to the OSI model
G.711
G.722
G.728
G.729
G.723.1.1
Presentation
H.261 ... H.323 RAS signaling
zone 1
zone 2
Hình 3: kiến trúc tại Terminal H.323 cña Cisco
Video Conference Architecture
a typical H.323 Terminal
Video I/O
Equipment
Audio I/O
Equipment
User Data
Applications
System
Control
User
Interface
H.225.0
Layer
Locall
Area
Network
Intererface
recovery
Path
Delay
Video ... Data
Applications
System
Control
User
Interface
H.225.0
Layer
Locall
Area
Network
Intererface
recovery
Path
Delay
Video
codec
H261,
H263
Audio
condec
G711, G722,
G723, G728
G729
System control
1. Setup
2. Alerting
3....
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Tài liệu overview of data modeling and database design pptx
Ngày tải lên :
10/12/2013, 17:15
... course description.
Overview of Data Modeling and Database Design 8Ć9
Database Design
Designing a relational database system involves converting a model into a workable
software representation. The ... is the amount of space required to store the
data of a table in the database.
D
Redefine integrity constraints.
For more information, see
Develop Complex Data Models and Design Databases course ... attribute.
Overview of Data Modeling and Database Design 8Ć29
Designing the Database
The database design stage produces design specifications for a relational database,
including definitions for relational...
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Tài liệu Modeling of Data part 1 pptx
Ngày tải lên :
15/12/2013, 04:15
...
Permission is granted for internet users to make one paper copy for their own personal use. Further reproduction, or any copying of machine-
readable files (including this one) to any servercomputer, ... graph of data and model “looks good.” This
approach is known as chi-by-eye. Luckily, its practitioners get what they deserve.
CITED REFERENCES AND FURTHER READING:
Bevington, P.R. 1969,
Data Reduction ... general principles is it based on? The answer
to these questions takes us into the subject of maximum likelihood estimators.
Given a particular data set of x
i
’s and y
i
’s, we have the intuitive...
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Tài liệu Modeling of Data part 2 doc
Ngày tải lên :
15/12/2013, 04:15
... [1]
15.2 Fitting Data to a Straight Line
A concrete example will make the considerations of the previous section more
meaningful. We consider the problem of fitting a set of N data points (x
i
,y
i
)to
a ... that the model does fit well, then we can proceed by first assigning an arbitrary
constant σ to all points, next fitting for the model parameters by minimizing χ
2
,
and finally recomputing
σ
2
=
N
i=1
[y
i
− ... 68 percent of the time, within ±2σ 95 percent
of the time, and within ±3σ 99.7 percent of the time. Extending this, one would
expect a measurement to be off by 20 only one time out of 2 ì 10
88
.Weall
know...
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Tài liệu Modeling of Data part 3 docx
Ngày tải lên :
15/12/2013, 04:15
... [1]
15.2 Fitting Data to a Straight Line
A concrete example will make the considerations of the previous section more
meaningful. We consider the problem of fitting a set of N data points (x
i
,y
i
)to
a ... ith point. The
weighted sum of variances in the denominator of equation (15.3.2) can be understood both
as the variance in the direction of the smallest χ
2
between each data point and the line ... *chi2, float *q)
Given a set of data points
x[1 ndata]
,
y[1 ndata]
with individual standard deviations
sig[1 ndata]
, fit them to a straight line y = a + bx by minimizing χ
2
. Returned are
a,b
and...
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Tài liệu Modeling of Data part 4 pptx
Ngày tải lên :
15/12/2013, 04:15
... ith point. The
weighted sum of variances in the denominator of equation (15.3.2) can be understood both
as the variance in the direction of the smallest χ
2
between each data point and the line ... ensure
that the minimum with respect to b is also minimized with respect to a.
668
Chapter 15. Modeling of Data
Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521-43108-5)
Copyright ... projection of the confidence region onto
the a axis. In the figure, we have found the point labeled B;tofindσ
a
we need to find the
666
Chapter 15. Modeling of Data
Sample page from NUMERICAL RECIPES IN...
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Tài liệu Modeling of Data part 5 doc
Ngày tải lên :
15/12/2013, 04:15
... learn more about identifying and treating such cases
in Đ15.6. In the following routine, the point at which this kind of editing would
occur is indicated.
Generallyspeaking, werecommend that youalwaysuseSVD ... .
X
M
(x
N
)
σ
N
data points
basis functions
Figure 15.4.1. Design matrix for the least-squares fit of a linear combination of M basis functions to N
data points. The matrix elements involve the basis functions ... a factor of 3 on the linear algebra by switching to LU decomposition, without
674
Chapter 15. Modeling of Data
Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN...
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Tài liệu Modeling Of Data part 6 pdf
Ngày tải lên :
15/12/2013, 04:15
... i.
Inclusion of the second-derivative term can in fact be destabilizing if the model
fits badly or is contaminated by outlier points that are unlikely to be offset by
compensating points of opposite ... covsrt(float **covar, int ma, int ia[], int mfit);
void gaussj(float **a, int n, float **b, int m);
void mrqcof(float x[], float y[], float sig[], int ndata, float a[],
int ia[], int ma, float **alpha, ... [], int), float *alamda)
Levenberg-Marquardt method, attempting to reduce the value χ
2
of a fit between a set of data
points
x[1 ndata]
,
y[1 ndata]
with individual standard deviations
sig[1 ndata]
,
and...
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Tài liệu Modeling Of Data part 7 pptx
Ngày tải lên :
15/12/2013, 04:15
... find some way of estimating or approximating
the probability distributionof a
(i)
−a
true
without knowing a
true
and withouthaving
available to us an in nite universe of hypothetical data sets.
Monte ... a minimum at a
(0)
. Call this minimum value χ
2
min
.If
696
Chapter 15. Modeling of Data
Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521-43108-5)
Copyright ... departures for all data points, or else fractionally large departures for a small
number of data points. It is the latter interpretation, leading to the notion of outlier
points, that is generally...
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Tài liệu Modeling Of Data part 8 pptx
Ngày tải lên :
15/12/2013, 04:15
... thus obtained
are then used as starting values in amoeba, now using the robust choice of ρ and
minimizing the expression (15.7.3).
Fitting a Line by Minimizing Absolute Deviation
Occasionally ... Such discontinuities frequently wreak havoc on both general
nonlinear equation solvers and general function minimizing routines. You might
now think of rejecting (15.7.8) in favor of (15.7.10), ... departures for all data points, or else fractionally large departures for a small
number of data points. It is the latter interpretation, leading to the notion of outlier
points, that is generally...
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