functions of data link layer ppt
Tài liệu Module 7- Data Link Layer CCNA Exploration 4.0 pptx
Ngày tải lên :
22/12/2013, 13:17
... www.bkacad.com
Connecting Upper Layer Services to the Media
11
• 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.
– ... www.bkacad.com
Overview
Upon completion of this chapter, you will be able to:
• Explain the role of Data Link layer protocols in data transmission.
• Describe how the Data Link layer prepares data for transmission ... Data Link Layer Protocols- The Frame
31
• Remember that although there are many different Data Link layer protocols that describe
Data Link layer frames, each frame...
- 64
- 507
- 0
Tài liệu Statistical Description of Data part 9 pptx
Ngày tải lên :
15/12/2013, 04:15
... 900
Figure 14.8.1. Top: Synthetic noisy data consisting of a sequence of progressively narrower bumps,
and additive Gaussian white noise. Center: Result of smoothing the data by a simple moving window
average. ... synthetic data. Bottom: Result of smoothing the data by a Savitzky-Golay
smoothing filter (of degree 4) using the same 33 points. While there is less smoothing of the broadest
feature, narrower ... panels.) The widths of the bumps (full width at half of maximum, or FWHM) are
140, 43, 24, 17, 13, and 10, respectively.
The middle panel of Figure 14.8.1 shows the result of smoothing by a moving...
- 6
- 407
- 0
Tài liệu Modeling of Data part 1 pptx
Ngày tải lên :
15/12/2013, 04:15
... measure of goodness -of- fit. When the third item suggests that the model
is an unlikely match to the data, then items (i) and (ii) are probably worthless.
Unfortunately, many practitioners of parameter ... 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 ... 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 feeling that
some parameter...
- 2
- 391
- 0
Tài liệu Modeling of Data part 4 pptx
Ngày tải lên :
15/12/2013, 04:15
... float *xx,*yy,*sx,*sy,*ww,aa,offs;
float chixy(float bang)
Captive function of
fitexy
, returns the value of (χ
2
−
offs
) for the slope
b=tan(bang)
.
Scaled data and
offs
are communicated via the ... variance of the linear combination y
i
− a − bx
i
of two random
variables x
i
and y
i
,
Var(y
i
− a − bx
i
)=Var(y
i
)+b
2
Var(x
i
)=σ
2
yi
+b
2
σ
2
xi
≡1/w
i
(15.3.3)
The sum of the square of N ... large that the data are
consistent with a vertical (infinite b) line. If
siga
and
sigb
are returned as
BIG
, then the data
are consistent with all values of b.
{
void avevar(float data[ ], unsigned...
- 6
- 396
- 0
Tài liệu Modeling Of Data part 7 pptx
Ngày tải lên :
15/12/2013, 04:15
... value of a measured quantity, or the mean of some function
of the measured quantities.
The bootstrap method
[1]
uses the actual data set D
S
(0)
, with its N data points, to
generate any number of ... or different data
reduction techniques, and seek to minimize the uncertainty of the result according
to any desired criteria. Offered the choice between mastery of a five-foot shelf of
analytical ... even when they must be offered without proof.
Figure 15.6.1 shows the conceptual scheme of an experiment that “measures”
a set of parameters. There is some underlying true set of parameters a
true
that...
- 11
- 465
- 0
Tài liệu Modeling Of Data part 8 pptx
Ngày tải lên :
15/12/2013, 04:15
... *arr,d,sum=0.0;
arr=vector(1,ndatat);
for (j=1;j<=ndatat;j++) arr[j]=yt[j]-b*xt[j];
if (ndatat & 1) {
aa=select((ndatat+1)>>1,ndatat,arr);
}
else {
j=ndatat >> 1;
aa=0.5*(select(j,ndatat,arr)+select(j+1,ndatat,arr));
}
abdevt=0.0;
for ... on the following fact: The median c
M
of a set
of numbers c
i
is also that value which minimizes the sum of the absolute deviations
i
|c
i
− c
M
|
(Proof: Differentiate the above expression ... fractionally
small 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...
- 8
- 346
- 0
Tài liệu Module 9: The Transactional Data Access Layer pptx
Ngày tải lên :
17/01/2014, 09:20
... same data
access technologies as that of the nontransactional DAL. The following data
access technologies were covered in Module 8, “The Nontransactional Data
Access Layer :
!
Microsoft Data ... data services layer. The transactional DAL can return to the
business logic layer either success or failure. If the transaction also involved
retrieving data as a result of updates to the data, ...
DAL: Module 8, “The Nontransactional Data Access Layer and Module 9,
“The Transactional Data Access Layer. ” The DAL is an application’s means of
access to data services.
After completing this...
- 34
- 324
- 0
Tài liệu Chapter 7 :Data Link Control ppt
Ngày tải lên :
16/02/2014, 08:20
... frame
i+1
out of sequence
Receiver send reject
i
Transmitter goes back to frame
i
and
retransmits
William Stallings
Data and Computer
Communications
Chapter 7
Data Link Control
Cyclic ... Access Procedure, Balanced (LAPB)
Part of X.25 (ITU-T)
Subset of HDLC - ABM
Point to point link between system and packet
switching network node
Link Access Procedure, D-Channel
ISDN ... code
Parity
Value of parity bit is such that character has even
(even parity) or odd (odd parity) number of ones
Even number of bit errors goes undetected
HDLC Operation
Exchange of information,...
- 51
- 851
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P3 pptx
Ngày tải lên :
03/07/2014, 08:20
... power of a
memory hierarchy comes from its ability to take advantage of patterns of data
use that are transient. Repeated requests tend to be made to a given data item
over a short period of ... best advantage. The emphasis of the book will be on the practical
applications of such results.
The focus of the applications examined in this book is on the portion of a
computer system’s memory ... vendors, vendors often offer such reporting as a differentiating feature.
As befits a work about fractal modeling, the chapters of the book cover
events that play out at a wide range of time scales....
- 5
- 235
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P7 ppt
Ngày tải lên :
03/07/2014, 08:20
... STRUCTURE OF DATA REFERENCE
Figure 1.7.
time.
CICS storage pools: cache performance as a function of average cache residency
Figure 1.8.
time.
IMS storage pools: cache performance as a function of ... function of cache size. Just as the miss ratio, as a function of the
single
-
reference residency time, takes the form of a simple power law, so does
the miss ratio, as a function of cache ... experienced by a
wide range of cached data.
Figures 1.4 through 1.10 present the performance of a “plain vanilla” cache,
relative to average residency time, for a range of application storage pools....
- 5
- 253
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P9 ppt
Ngày tải lên :
03/07/2014, 08:20
... CICS storage pools: distribution oftrack interarrival times.
Figure 1.14. CICS storage pools: distribution ofrecord interarrival times.
30 THE FRACTAL STRUCTURE OF DATA REFERENCE
Figure 1.15. IMS ... storage pools: distribution of track interarrival times.
Figure 1. 16.
IMS storage pools: distribution of record interarrival times.
28 THE FRACTAL STRUCTURE OF DATA REFERENCE
Figure 1.11.
DB2 ... pools: distribution oftrack interarrival times.
Figure 1.12. DB2 storage pools: distribution ofrecord interarrival times.
26
operating separately [ 18]:
THE FRACTAL STRUCTURE OF DATA REFERENCE
(1.26)
(Note,...
- 5
- 233
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P12 ppt
Ngày tải lên :
03/07/2014, 08:20
...
well.
42 THE FRACTAL STRUCTURE OF DATA REFERENCE
A general
-
purpose technique exists for generating synthetic patterns of ref
-
erence, which is also capable of producing references that conform ... concept of stack
distance, or the depth at which previously referenced data items appear in the
LRU list [8, 21]. The idea is to build a history of previous references (organized
in the form of ...
variety of individual “daemons”, large numbers of which can run concurrently
and independently. This type of benchmark structure is attractive, in that
it mirrors, at a high level, the behavior of...
- 5
- 274
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P14 ppt
Ngày tải lên :
03/07/2014, 08:20
... FRACTAL STRUCTURE OF DATA REFERENCE
Table 4.1. Busiest 20 files (data sets) in the case study.
Use of Memory at the I/O Interface
53
meant that all memory deployment strategies of interest could ... manage database
files. Databases constructed using DataBase 2 (
DB2) and Information Man
-
agement System (IMS) database management software were also in heavy use.
Most database storage was contained ... (
VSAM)
files.
Our examination of the installation of the case study is based on a trace of all
storage subsystem
I/O during 30 minutes of the morning peak. The busiest 20
files (alsocalleddatasets)appearing...
- 5
- 300
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P16 pptx
Ngày tải lên :
03/07/2014, 08:20
... determine the best
trade
-
off of memory among the n workloads.
The optimal allocation of memory must be the one for which the marginal
benefit (reduction of delays), per unit of added cache memory, ... a point of reference. Thus, we normalize the individual
partition
I/O rates relative to :
(5.5)
Memory Management in an LRU Cache
63
misses, in units of seconds of delay per second of clock ... management of cache memory is therefore optimal.
1.1 IMPACT OF MEMORY PARTITIONING
In the assumptions stated at the beginning of the section, we excluded those
cases, such as a complete lack of
I/O,...
- 5
- 311
- 1
THE FRACTAL STRUCTURE OF DATA REFERENCE- P19 ppt
Ngày tải lên :
03/07/2014, 08:20
... probability of further updates is highest shortly afterward.
THE FRACTAL STRUCTURE OF DATA REFERENCE
IMPACT OF TRANSIENT DATA ACCESS
Figure 6.2.
also presented in Figure 1.2.
Distribution of time ... reflects how
quickly data are written to disk relative to the overall lifetime of the data. We
should expect its value to be of the same order as the ratio of “dirty” data items
in cache, relative ... overall number of data items on disk. The value of d
would typically range from nearly zero (almost no buffering of writes) up to a
few tenths of a percent. Since a wide range of this ratio might...
- 5
- 311
- 1
