barcode generator visual basic 6 source code Contents in .NET

Maker Data Matrix ECC200 in .NET Contents

The service time at each bridge is deterministic with the forwarding rate of 10,000 frames/set. And, of course, the coefficient of variation is 0 in this case. The service time of the Ethernet is given by the sum of the transfer time Tt and the delay time Td of a frame. To obtain the transfer time Tt we need the mean frame length, which we get from Table 13.9 given that the minimum frame size is 72 bytes in the CSMA/CD case. Thus, 54.1% of the frames have a size between 72 and 95 bytes and it follows: Leth = 395 bytes = 3160 bit, ciplJL = 1.51.

Create and use your own functions. In addition to using the built-in functions in Access, you can create and work with your own functions by using VBA code. Use Automation to communicate with other Windows applications or to run systemlevel actions. You can write code to see whether a file exists before you take some action, or you can communicate with another Windows application (such as a spreadsheet), passing data back and forth. Use existing functions in external Windows Dynamic Link Libraries (DLLs). Macros don t enable you to call functions in other Windows DLLs. Work with records one at a time. If you need to step through records or move values from a record to variables for manipulation, code is the answer. Create or manipulate objects. In most cases, you ll find that creating and modifying an object is easiest in that object s Design view. In some situations, however, you may want to manipulate the definition of an object in code. With a few VBA statements, you can manipulate virtually any and all objects in a database, including the database itself. Display a progress meter on the status bar. If you need to display a progress meter to communicate progress to the user, VBA code is the answer. Macros are required by Access Web databases. Access 2010 supports a new type of database that is used only in SharePoint 2010. A Web-enabled database requires the use of macros instead of VBA for all of its forms and reports.

Have frequent, personal contact with each of your employees. Your employees won t feel that they have your support if you don t interact with them on a frequent basis. Some employees need more interaction than others, so it s your job to determine how much to provide, to whom, and how often. Recognize the true potential of your employees. Take time to assess and help further develop your employees skills and interests, hopes, and dreams while correcting any shortfalls that they may

Our next case study comes from prepayment metering. In many systems, the user pays in one place for a token whether a magic number, or a cardboard ticket with a magnetic strip, or even a rechargeable token such as a smartcard and uses this stored value in some other place. Examples include postal franking machines, the stored value cards that operate photocopiers in libraries, lift passes at ski resorts, and washing machine tokens in university residence halls. Many transport tickets are similar especially if the terminals that validate the tickets are mounted on buses or trains, and so are not usually online. The main protection goal in these systems is to prevent the stored value tokens being duplicated or forged en masse. Duplicating a single subway ticket is not too hard, and repeating a magic number a second time is trivial. This can be made irrelevant if we make all the tokens unique and log their use at both ends. But things get more complicated when the device that accepts the token does not have a channel of communication back to the ticket issuer; in this case, all the replay and forgery detection must be done offline, on a terminal that is often vulnerable to physical attack. So if we simply enciphered all our tokens using a universal master key, we might expect that a villain would extract this key from a stolen terminal, then set up as a token vendor in competition with us. There are also attacks on the server end of things. One neat attack on a vending card system used in the staff cafeteria of one of our local supermarkets exploited the fact that when a card was recharged, the vending machine first read the old amount, then asked for money, and then wrote the amended amount. The attack was to insert a card with some money in it, say, 49, on top of a blank card. The top card would then be removed and a 1 coin inserted in the machine, which would duly write 50 to the blank card. This left the perpetrator with two cards, with a total value of 99. This kind of attack was supposed to be prevented by two levers that extended to grip the card in the machine. However, by cutting the corners off the top card, this precaution could easily be defeated (see Figure 10.1) [479]. This attack is interesting because no amount of encryption of the card contents would make any difference. Although it could, in theory, be stopped by keeping logs at both ends, the design would not be trivial. But we mustn t get carried away with neat tricks like this, or we risk getting so involved with even more clever countermeasures that we fall prey to the Titanic effect again by ignoring the system-level issues. In most ticketing systems, petty fraud is easy. A free rider can jump the barrier at a subway station; an electricity meter can have a bypass switch wired across it; while barcoded ski lift passes, parking lot tickets, and the like can be forged with a scanner and printer. The goal is to prevent fraud becoming systematic. Petty fraud should be at least slightly inconvenient and more importantly there should be more serious mechanisms to prevent anyone forging tickets on a large enough scale to develop a black market that could affect your client s business. The example I ll discuss in detail is the prepayment electricity meter. I chose this because I was lucky enough to consult on a project to electrify more than 2.5 million households in South Africa (a central election pledge made by Nelson Mandela when

module bitwise (inputA, inputB, inputC, inputD, outputA, outputB, outputC, outputD, outputE); input inputA, inputB, inputC; input [2:0] inputD; output outputA, outputB, outputC, outputE; output [2:0] outputD; wire outputA, outputB, outputC, outputE; wire [2:0] outputD; // for bitwise AND assign outputA = inputA & inputB; // for bitwise OR assign outputB = inputA | inputB; // for bitwise NOT assign outputC = ~inputC; // for bitwise XOR assign outputE = inputA ^ inputB;

New collections are created using the Create Collection button. You can rename the collection by typing a new name in the Copy Collections drop-down list at the top of the Copy/Paste rollout. Collections of postures, poses, and tracks can be saved as files using the Save Collection button and reloaded using the Load Collections button found in the Copy/Paste rollout. All saved postures, poses, and tracks are saved using the .cpy extension. Buttons are available for deleting the current collection or all collections. The Max Load Preferences button opens a simple dialog box with options to Keep Existing Collections and Load Collections when a Max file is loaded.

Garc a Mart nez, Florentino. The Dead Sea Scrolls Translated: The Qumran Texts in English, 2nd edn., trans. Wilfred G. E. Watson. Leiden: Brill; Grand Rapids, MI: William B. Eerdmans, 1996. Garc a Mart nez, Florentino, and Julio Trebolle Barrera. The People of the Dead Sea Scrolls, trans. Wilfred G. E. Watson. Leiden: Brill, 1995.