function of data link layer ppt

... 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. – ... 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 ... Data Link Layer Protocols- The Frame 31 ã Remember that although there are many different Data Link layer protocols that describe Data Link layer frames, each frame...

Ngày tải lên: 22/12/2013, 13:17

... shows a test function, constructed to have six “bumps” of varying widths, all of height 8 units. To this function Gaussian white noise of unit variance has been added. (The test function without ... 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...

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...

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 ... 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 with slope ... 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...

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...

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 ... the function ρ(z) is a function of a single variable z ≡ [y i − y(x i )]/σ i . If we now define the derivative of ρ(z) to be a function ψ(z), ψ(z) ≡ dρ(z) dz (15.7.4) then the generalization of ... 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...

Ngày tải lên: 15/12/2013, 04:15

... 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...

Ngày tải lên: 17/01/2014, 09:20

... 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 ... 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,...

Ngày tải lên: 16/02/2014, 08:20

... form of cyprosin was processed in different isoforms by the excision of the prosegment and of most of the PSI [21]. Conversely to what has been found in vivo [31], heavy and light chains of the ... total or partial removal of the internal Fig. 1. Plant aspartic proteinase precursors. Comparison of the amino acid sequences of representative members of the A1 family of plant aspartic proteinases. ... a-helices linked with each other by three disulfide bridges. A unique feature of the PSI is the swap of the N- and C-terminal portions of the saposin-like domain, where the C-terminal portion of one...

Ngày tải lên: 19/02/2014, 12:20

... 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....

Ngày tải lên: 03/07/2014, 08:20

... as a 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 ... 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 ... 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....

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. ... 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,...

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...

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...

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,...

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 05/07/2014, 06:20

Ngày tải lên: 05/07/2014, 06:20

Ngày tải lên: 05/07/2014, 06:20