major responsibilities of data link layer

Ngày tải lên: 22/12/2013, 13:17

... with other frames sent in [t 0 -1,t 0 +1] 5: DataLink Layer 5-2 Chapter 5: The Data Link Layer Our goals: ❒ understand principles behind data link layer services: ❍ error detection, correction ❍ sharing ... channel: multiple access ❍ link layer addressing ❍ reliable data transfer, flow control: done! ❒ instantiation and implementation of various link layer technologies 5: DataLink Layer 5-49 Star topology ❒ Bus ... etc ❍ extracts datagram, passes to rcving node ❒ adapter is semi- autonomous ❒ link & physical layers sending node frame rcving node datagram frame adapter adapter link layer protocol 5: DataLink Layer...

Ngày tải lên: 12/09/2012, 15:06

... of TCP be affected in by the use of wifi connections? 3. What does the use of the mechanism of fast retransmit improve the performances of TCP in wireless environments in? 4. Another series of ... information such as the type of packet and the address of the recipient. The body contains the data to transmit. The radio layer uses the dispersion of spectrum by jumping of FHSS frequency (Frequency ... level of layer 2 (IEEE 802.11), a frame is lost, it will be retransmitted. It may be thus that the protocol of layer 2 transmits twice the same packet. If this packet contains a segment of TCP...

Ngày tải lên: 17/09/2012, 09:13

... former, 83.3% of the teacher often grouped students of the same sex while only 20% of the students chose it and for the latter, group students of different sexes was the choice of 80% of the students ... understanding of using group work in the speaking lesson at VUC. 1.2. Aims of the study The purpose of this study is to explore the reality of the use of group work in the speaking lesson of 1 st - ... process of group work. However, these studies have focused on the process of group work implementation in speaking lesson of non -major English students. A research into this area for English majors...

Ngày tải lên: 07/11/2012, 14:50

... + HF – (thoại tương tự) + VHF Data link: VDL Mode2 – (dữ liệu), VDL mode3 - (thoại và dữ liệu), và VDL mode4 - (dữ liệu). + SSR Mode S - (dữ liệu) + HF Data link – (dữ liệu). Các dịch vụ thông ... trên vùng lãnh thổ Việt Nam. Luận văn “ ỨNG DỤNG CỦA VHF DATA LINK MODE 4 TRONG MÔI TRƯỜNG CNS/ ATM ” nghiên cứu công nghệ kỹ thuật VHF Data Link Mode 4, một liên kết dữ liệu số sử dụng sóng VHF ... phân lớp điều khiển truy nhập MAC ( Medium Access Control ), Dịch vụ liên kết dữ liệu DLS ( Data Link service ) và thực thể quản lý liên kết ( LME ). Lớp liên kết dữ liệu VDL cung cấp sự truyền...

Ngày tải lên: 22/11/2012, 09:13

Ngày tải lên: 23/08/2013, 10:37

Ngày tải lên: 05/09/2013, 16:10

... unnamedTable = new System .Data. DataTable(); System .Data. DataTable namedTable = new System .Data. DataTable("Customer"); Visual Basic Dim unnamedTable As New System .Data. DataTable() Dim namedTable ... tabular data as a collection of collections. Each DataTable object contains a collection of ordered rows, each existing as an instance of a DataRow object. Each row contains its own collection of ... is the process of crafting tables that ensure data integrity and take advantage of the processing power of relational database systems. E.F. Codd, inventor of the relational database model,...

Ngày tải lên: 03/10/2013, 00:20

... parts of the database that are in use by the object model should have been generated. CHAPTER 8 ■ DATA ACCESS LAYER 164 DATABASE KEYS Database tables should always have some sort of key ... important, independent of the DataMapper itself (see Figure 8–6). Only the clients of the DataMapper are aware of its existence and use it to interact with the RDBMS. Figure 8–6. The DataMapper pattern: ... different types of User C H A P T E R 8 ■ ■ ■ 163 Data Access Layer Silverlight and some WPF applications do not use offline storage for persisting data. Instead, they use a relational database...

Ngày tải lên: 03/10/2013, 01:20

... tendency, the moments of a distribution, the median and mode. In §14.2 we learn to test whether different data sets are drawn from distributions with different values of these measures of central tendency. ... of integer powers of the values. Best known is the mean of the values x 1 , ,x N , x= 1 N N  j=1 x j (14.1.1) which estimates the value around which central clustering occurs. Note the use of an ... 610 Chapter 14. Statistical Description of Data Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521-43108-5) Copyright (C) 1988-1992...

Ngày tải lên: 20/10/2013, 17:15

... tendency, the moments of a distribution,the median and mode. In §14.2 we learn to test whether different data sets are drawn from distributions with different values of these measures of central tendency. ... of integer powers of the values. Best known is the mean of the values x 1 , ,x N , x= 1 N N  j=1 x j (14.1.1) which estimates the value around which central clustering occurs. Note the use of an ... the mean is not the only available estimator of this 614 Chapter 14. Statistical Description of Data Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521-43108-5) Copyright...

Ngày tải lên: 24/10/2013, 15:15

... makes use of the following routine for computing the mean and variance of a set of numbers, 620 Chapter 14. Statistical Description of Data Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC ... routine void ftest(float data1 [], unsigned long n1, float data2 [], unsigned long n2, float *f, float *prob) Given the arrays data1 [1 n1] and data2 [1 n2] , this routine returns the value of f ,and its significance ... 1 degrees of freedom. The routine is #include <math.h> void tptest(float data1 [], float data2 [], unsigned long n, float *t, float *prob) Given the paired arrays data1 [1 n] and data2 [1 n] ,...

Ngày tải lên: 24/10/2013, 15:15

... the data sets are drawn from the same distribution. Small values of prob show that the cumulative distribution function of data1 is significantly different from that of data2 . The arrays data1 and data2 are ... number of data points, N e = N for the case (14.3.5) of one distribution, and N e = N 1 N 2 N 1 + N 2 (14.3.10) for the case (14.3.6) of two distributions, where N 1 is the number of data points ... consider the case of comparing two binned data sets. Let R i be the number of events in bin i for the first data set, S i the number of events in the same bin i for the second data set. Then the...

Ngày tải lên: 28/10/2013, 22:15

... . . 1. red # of red males N 11 # of red females N 21 # of green females N 22 # of green males N 12 # of males N 1 ⋅ # of females N 2 ⋅ 2. green # of red N ⋅ 1 # of green N ⋅ 2 total ... number of degrees of freedom is equal to the number of entries in the table (product of its row size and column size) minus the number of constraints that have arisen from our use of the data themselves ... since the total of the column totals and the total of the row totals both equal N, the total number of data points. Therefore, if the table is of size I by J, the number of degrees of freedom is IJ...

Ngày tải lên: 28/10/2013, 22:15

... second of two modules that focus on the data access layer (DAL). In Module 8, “The Nontransactional Data Access Layer, ” you learned about data retrieval. In this module, you will learn about data ... 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 ... 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: 05/11/2013, 12:15

... respectively, the number of data points in the measurement of r 1 and r 2 . All of the significances above are two-sided. If you wish to disprove the null hypothesis in favor of a one-sided hypothesis, ... is the mean of the x i ’s, y is the mean of the y i ’s. The value of r lies between −1 and 1, inclusive. It takes on a value of 1,termed “complete positive correlation,” when the data points ... concept of nonparametric correlation is this: If we replace the value of each x i by the value of its rank among all the other x i ’s in the sample, that is, 1, 2, 3, ,N, then the resulting list of...

Ngày tải lên: 07/11/2013, 19:15

Ngày tải lên: 07/11/2013, 19:15