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  • Working with ieee format numbers in ARM

    - by Jake Sellers
    I'm trying to write an ARM program that will convert an ieee number to a TNS format number. TNS is a format used by some super computers, and is similar to ieee but different. I'm trying to use several masks to place the three different "part" of the ieee number in separate registers so I can move them around accordingly. Here is my unpack subroutine: UnpackIEEE LDR r1, SMASK ;load the sign bit mask into r1 LDR r2, EMASK ;load the exponent mask into r2 LDR r3, GMASK ;load the significand mask into r3 AND r4, r0, r1 ;apply sign mask to IEEE and save into r4 AND r5, r0, r2 ;apply exponent mask to IEEE and save into r5 AND r6, r0, r3 ;apply significand mask to IEEE and save into r6 MOV pc, r14 ;return And here are the masks and number declarations so you can understand: IEEE DCD 0x40300000 ;2.75 decimal or 01000000001100000000000000000000 binary SMASK DCD 0x80000000 ;Sign bit mask EMASK DCD 0x7F800000 ;Exponent mask GMASK DCD 0x007FFFFF ;Significand mask When I step through with the debugger, the results I get are not what I expect after working through it on paper. EDIT: What I mean, is that after the subroutine runs, registers 4, 5, and 6 all remain 0. I can't figure out why the masks are not working. I think I do not fully understand how the number is being stored in the register or using the masks wrong. Any help appreciated. If you need more info just ask. EDIT: entry point: Very simple, just trying to get these subroutines working. ENTRY LDR r1, IEEE ;load IEEE num into r1 BL UnpackIEEE ;call unpack sub SWI SWI_Exit ;finish

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  • IEEE 1394 Firewire Card is not visible in Device Manager in WIndows 7

    - by Shyam
    I have a IEEE 1394 card that I have placed in one of the PCI slots of my Windows 7 PC. I have moved to Windows just last week and Windows is not detecting this card. It is not listed in the Devide Manager. Earlier when I used Fedora 12, I was able to use this interface for capturing videos from my DV Camera. The manufacturer is Tech-Com, which has not provided a driver CD for this. What can I possibly try?

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  • Exact textual representation of an IEEE "double"

    - by CyberShadow
    I need to represent an IEEE 754-1985 double (64-bit) floating point number in a human-readable textual form, with the condition that the textual form can be parsed back into exactly the same (bit-wise) number. Is this possible/practical to do without just printing the raw bytes? If yes, code to do this would be much appreciated.

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  • Convert ieee 754 float to hex with c - printf

    - by Michael
    Ideally the following code would take a float in IEEE 754 representation and convert it into hexadecimal void convert() //gets the float input from user and turns it into hexadecimal { float f; printf("Enter float: "); scanf("%f", &f); printf("hex is %x", f); } I'm not too sure what's going wrong. It's converting the number into a hexadecimal number, but a very wrong one. 123.1443 gives 40000000 43.3 gives 60000000 8 gives 0 so it's doing something, I'm just not too sure what. Help would be appreciated

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  • Recording/Reading C doubles in the IEEE 754 interchange format

    - by rampion
    So I'm serializing a C data structure for cross-platform use, and I want to make sure I'm recording my floating point numbers in a cross-platform manner. I had been planning on just doing char * pos; /*...*/ *((double*) pos) = dataStructureInstance->fieldWithOfTypeDouble; pos += sizeof(double); But I wasn't sure that the bytes would be recorded in the char * array in the IEEE 754 interchange format. I've been bitten by cross-platform issues before (endian-ness and whatnot). Is there anything I need to do to a double to get the bytes in interchange format?

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  • Convert pre-IEEE-574 C++ floating-point numbers to/from C#

    - by Richard Kucia
    Before .Net, before math coprocessors, before IEEE-574, Microsoft defined a bit pattern for floating-point numbers. Old versions of the C++ compiler happily used that definition. I am writing a C# app that needs to read/write such floating-point numbers in a file. How can I do the conversions between the 2 bit formats? I need conversion methods in both directions. This app is going to run in a PocketPC/WinCE environment. Changing the structure of the file is out-of-scope for this project. Is there a C++ compiler option that instructs it to use the old FP format? That would be ideal. I could then exchange data between the C# code and C++ code by using a null-terminated text string, and the C++ methods would be simple wrappers around sprintf and atof functions. At the very least, I'm hoping someone can reply with the bit definitions for the old FP format, so I can put together a low-level bit manipulation algorithm if necessary. Thanks.

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  • Read half precision float (float16 IEEE 754r) binary data in matlab

    - by Michael
    you have been a great help last time, i hope you can give me some advise this time, too. I read a binary file into matlab with bit16 (format = bitn) and i get a string of ones and zeros. bin = '1 00011 1111111111' (16 bits: 1. sign, 2-6. exponent, 7-16. mantissa) According to ftp://www.fox-toolkit.org/pub/fasthalffloatconversion.pdf it can be 'converted' like out = (-1)^bin(1) * 2^(bin(2:6)-15) * 1.bin(7:16) [are exponent and mantissa still binary?] Can someone help me out and tell me how to deal with the 'eeeee' and '1.mmmmmmmmmm' as mentioned in the pdf, please. Thanks a lot! Michael

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  • IEEE 1003.1 licenses compared

    - by LarsOn
    Software or real people can technically copy a BSD software, install it and sell it. What are technical and licence advantages and disadvantages compared to taking Linux or other 1003.1 and delivering or selling it? Which license is most flexible for instance when selling or delivering a computer BSD licence seems more flexible than Linux and other specs also interesting (Haiku and likewise). Typical case someone wants a computer with which we can deliver BSD or Linux quite similar weighing licence flexibility (BSD seems best licence) and functions (Linux seems have most functions)

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  • how IEEE-754 floating point numbers work

    - by hatorade
    Let's say I have this: float i = 1.5 in binary, this float is represented as: 0 01111111 10000000000000000000000 I broke up the binary to represent the 'signed', 'exponent' and 'fraction' chunks. What I don't understand is how this represents 1.5. The exponent is 0 once you subtract the bias (127 - 127), and the fraction part with the implicit leading one is 1.1. How does 1.1 scaled by nothing = 1.5???

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  • What are the IEEE and ACM good for?

    - by Joshua Fox
    Membership in the IEEE and ACM is sometimes portrayed as a sign of professionalism. But all that is involved, as far as I can tell, is sending them your money. In return, besides the potential resume line, these organizations sponsor conferences and journals. I can always attend a conference or subscribe to or submit a paper to a journal, whether I am a member or not. If being a member makes some of that cheaper, or is a prerequisite for admission then OK, but I still don't see the purpose of these organizations. The answer, as far as I can gather, is that their most important value is to provide some reading material. I'd suggest that this is not worth the money given the wide availability of other valuable reading materials.

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  • Convert NSData to primitive variable with ieee-754 or twos-complement ?

    - by William GILLARD
    Hi every one. I am new programmer in Obj-C and cocoa. Im a trying to write a framework which will be used to read a binary files (Flexible Image Transport System or FITS binary files, usually used by astronomers). The binary data, that I am interested to extract, can have various formats and I get its properties by reading the header of the FITS file. Up to now, I manage to create a class to store the content of the FITS file and to isolate the header into a NSString object and the binary data into a NSData object. I also manage to write method which allow me to extract the key values from the header that are very valuable to interpret the binary data. I am now trying to convert the NSData object into a primitive array (array of double, int, short ...). But, here, I get stuck and would appreciate any help. According to the documentation I have about the FITS file, I have 5 possibilities to interpret the binary data depending on the value of the BITPIX key: BITPIX value | Data represented 8 | Char or unsigned binary int 16 | 16-bit two's complement binary integer 32 | 32-bit two's complement binary integer 64 | 64-bit two's complement binary integer -32 | IEEE single precision floating-point -64 | IEEE double precision floating-point I already write the peace of code, shown bellow, to try to convert the NSData into a primitive array. // self reefer to my FITS class which contain a NSString object // with the content of the header and a NSData object with the binary data. -(void*) GetArray { switch (BITPIX) { case 8: return [self GetArrayOfUInt]; break; case 16: return [self GetArrayOfInt]; break; case 32: return [self GetArrayOfLongInt]; break; case 64: return [self GetArrayOfLongLong]; break; case -32: return [self GetArrayOfFloat]; break; case -64: return [self GetArrayOfDouble]; break; default: return NULL; } } // then I show you the method to convert the NSData into a primitive array. // I restrict my example to the case of 'double'. Code is similar for other methods // just change double by 'unsigned int' (BITPIX 8), 'short' (BITPIX 16) // 'int' (BITPIX 32) 'long lon' (BITPIX 64), 'float' (BITPIX -32). -(double*) GetArrayOfDouble { int Nelements=[self NPIXEL]; // Metod to extract, from the header // the number of element into the array NSLog(@"TOTAL NUMBER OF ELEMENTS [%i]\n",Nelements); //CREATE THE ARRAY double (*array)[Nelements]; // Get the total number of bits in the binary data int Nbit = abs(BITPIX)*GCOUNT*(PCOUNT + Nelements); // GCOUNT and PCOUNT are defined // into the header NSLog(@"TOTAL NUMBER OF BIT [%i]\n",Nbit); int i=0; //FILL THE ARRAY double Value; for(int bit=0; bit < Nbit; bit+=sizeof(double)) { [Img getBytes:&Value range:NSMakeRange(bit,sizeof(double))]; NSLog(@"[%i]:(%u)%.8G\n",i,bit,Value); (*array)[i]=Value; i++; } return (*array); } However, the value I print in the loop are very different from the expected values (compared using official FITS software). Therefore, I think that the Obj-C double does not use the IEEE-754 convention as well as the Obj-C int are not twos-complement. I am really not familiar with this two convention (IEEE and twos-complement) and would like to know how I can do this conversion with Obj-C. In advance many thanks for any help or information.

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  • Who practices, or is likely to practice, the IEEE Software Engineering? [closed]

    - by user72757
    There is an interesting issue in Software Engineering which I'd like to explore. The issue is firstly what is and what is not software engineering. Secondly, if software engineering is what the IEEE defines it to be, what are good examples of companies which practice the SE? Detailed question: Software engineering (SE) is the application of a systematic, disciplined, quantifiable approach to the design, development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software. [updated definition, originating in 610.12-1990 - IEEE Standard Glossary of Software Engineering Terminology] If we consider as SE only those approaches that 100% match the above definition, we naturally get to SWEBOK (Software Engineering Body of Knowledge) which is created by the IEEE and the ACM. I'm seeking the answer to this: How can I find a company outside the defence industry which practices the SE as defined by IEEE? Clues: SE originates in 1968 NATO conference. The Software Engineering Institute (SEI) is based in the US at Carnegie Mellon University. Funding of the SEI is largely done by the US DoD. Defence industry uses the SE and sometimes has a partnership with the IEEE (as in case of Boeing). Possible decomposition of my big question into smaller chunks: a) Where is anyone who acknowledges the IEEE Software Engineering standards at work and perhaps even uses some of them? http://cs.hbg.psu.edu/cmpsc487/IEEEStds_List.htm b) Where can I find a person or a company building around SWEBOK? http://www.computer.org/portal/web/swebok/html/contents c) What is an example of a company professionally using CSDP (apart from those at IEEE website)? Does anyone have any possible contribution to this question?

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  • Are there any modern platforms with non-IEEE C/C++ float formats?

    - by Patrick Niedzielski
    Hi all, I am writing a video game, Humm and Strumm, which requires a network component in its game engine. I can deal with differences in endianness easily, but I have hit a wall in attempting to deal with possible float memory formats. I know that modern computers have all a standard integer format, but I have heard that they may not all use the IEEE standard for floating-point integers. Is this true? While certainly I could just output it as a character string into each packet, I would still have to convert to a "well-known format" of each client, regardless of the platform. The standard printf() and atod() would be inadequate. Please note, because this game is a Free/Open Source Software program that will run on GNU/Linux, *BSD, and Microsoft Windows, I cannot use any proprietary solutions, nor any single-platform solutions. Cheers, Patrick

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  • Les commutateurs HP E-Series à économie d'énergie intègrent le nouveau standard IEEE et diminuent le coût total de possession de 51 %

    Les commutateurs HP E-Series à économie d'énergie intègrent le nouveau standard IEEE et diminuent le coût total de possession de 51 % HP a annoncé le 6 janvier l'arrivée de ses premiers produits fondés sur un nouveau standard Ethernet à haute efficacité énergétique. Un standard que HP se félicite d'avoir aidé à développer, et qui permet aux entreprises de réduire la consommation énergétique et les coûts opérationnels des équipements IT. Le standard Ethernet à haute efficacité énergétique de l'IEEE (IEEE 802.3az) ajustant la consommation automatiquement en fonction du trafic réseau effectif entre les commutateurs et les autres équipements connectés au réseau, et ce, en temps réel.

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  • Why can't I connect to a Cisco wireless access point?

    - by spinlock
    I'm running a Lucid Netbook Remix on my Dell Inspiron 600m and I was not able to connect to the wireless network at the Hacker Dojo in Mountain View yesterday. There were plenty of other people on the network - MS, Mac, and Linux boxes - but my laptop would never get an ip address. I can connect to my home network, which is open, and I've never had a problem connecting at the coffee shop, which uses WPA. The Hacker Dojo is running WPA and we checked the password a number of times but got no love. Any ideas would be greatly appreciated. Additional Info: $iwlist eth1 scan eth1 Scan completed : Cell 01 - Address: EC:C8:82:FA:63:92 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:62 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 280ms ago Cell 02 - Address: 00:18:4D:24:08:61 ESSID:"Green Zone" Protocol:IEEE 802.11bg Mode:Master Frequency:2.417 GHz (Channel 2) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:23 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 11516ms ago Cell 03 - Address: 08:17:35:32:6E:13 ESSID:"\x00" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:71 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 2760ms ago Cell 04 - Address: EC:C8:82:FA:63:90 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:61 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 772ms ago Cell 05 - Address: 08:17:35:32:6E:11 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:65 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 3308ms ago Cell 06 - Address: 08:17:35:32:7E:31 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:88 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 1668ms ago Cell 07 - Address: 38:E7:D8:01:46:1E ESSID:"JWS_Incredible" Protocol:IEEE 802.11bg Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 500 kb/s; 54 Mb/s Quality:31 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK Extra: Last beacon: 2848ms ago Cell 08 - Address: 08:17:35:32:6E:10 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:67 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 7848ms ago Cell 09 - Address: 08:17:35:32:7E:30 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:85 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 8300ms ago Cell 10 - Address: 08:17:35:32:6E:12 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:68 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 232ms ago Cell 11 - Address: 08:17:35:32:7E:32 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:86 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 168ms ago Cell 12 - Address: EC:C8:82:FA:63:91 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:62 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 7408ms ago $iwconfig eth1 eth1 unassociated ESSID:"HackerDojo-gwifi" Nickname:"ipw2100" Mode:Managed Channel=0 Access Point: Not-Associated Bit Rate:0 kb/s Tx-Power:16 dBm Retry short limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0

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  • Join ACM, join IEEE, or read programming books?

    - by Laura
    I read blogs and listen to podcasts, and I own many of the "classic" programming books. For the money, what kind of printed material would you say is the most valuable to keep current in software engineering -- books, or magazines from professional organizations such as ACM and IEEE? Which organization has the best periodicals?

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  • problems in trying ieee 802.15.4 working from msk

    - by asel
    Hi, i took a msk code from dsplog.com and tried to modify it to test the ieee 802.15.4. There are several links on that site for ieee 802.15.4. Currently I am getting simulated ber results all approximately same for all the cases of Eb_No values. Can you help me to find why? thanks in advance! clear PN = [ 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0; 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0; 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0; 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1; 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1; 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0; 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1; 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1; 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1; 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1; 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1; 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0; 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0; 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1; 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0; 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0; ]; N = 5*10^5; % number of bits or symbols fsHz = 1; % sampling period T = 4; % symbol duration Eb_N0_dB = [0:10]; % multiple Eb/N0 values ct = cos(pi*[-T:N*T-1]/(2*T)); st = sin(pi*[-T:N*T-1]/(2*T)); for ii = 1:length(Eb_N0_dB) tx = []; % MSK Transmitter ipBit = round(rand(1,N/32)*15); for k=1:length(ipBit) sym = ipBit(k); tx = [tx PN((sym+1),1:end)]; end ipMod = 2*tx - 1; % BPSK modulation 0 -> -1, 1 -> 1 ai = kron(ipMod(1:2:end),ones(1,2*T)); % even bits aq = kron(ipMod(2:2:end),ones(1,2*T)); % odd bits ai = [ai zeros(1,T) ]; % padding with zero to make the matrix dimension match aq = [zeros(1,T) aq ]; % adding delay of T for Q-arm % MSK transmit waveform xt = 1/sqrt(T)*[ai.*ct + j*aq.*st]; % Additive White Gaussian Noise nt = 1/sqrt(2)*[randn(1,N*T+T) + j*randn(1,N*T+T)]; % white gaussian noise, 0dB variance % Noise addition yt = xt + 10^(-Eb_N0_dB(ii)/20)*nt; % additive white gaussian noise % MSK receiver % multiplying with cosine and sine waveforms xE = conv(real(yt).*ct,ones(1,2*T)); xO = conv(imag(yt).*st,ones(1,2*T)); bHat = zeros(1,N); bHat(1:2:end) = xE(2*T+1:2*T:end-2*T); % even bits bHat(2:2:end) = xO(3*T+1:2*T:end-T); % odd bits result=zeros(16,1); chiplen=32; seqstart=1; recovered = []; while(seqstart<length(bHat)) A = bHat(seqstart:seqstart+(chiplen-1)); for j=1:16 B = PN(j,1:end); result(j)=sum(A.*B); end [value,index] = max(result); recovered = [recovered (index-1)]; seqstart = seqstart+chiplen; end; %# create binary string - the 4 forces at least 4 bits bstr1 = dec2bin(ipBit,4); bstr2 = dec2bin(recovered,4); %# convert back to numbers (reshape so that zeros are preserved) out1 = str2num(reshape(bstr1',[],1))'; out2 = str2num(reshape(bstr2',[],1))'; % counting the errors nErr(ii) = size(find([out1 - out2]),2); end nErr/(length(ipBit)*4) % simulated ber theoryBer = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))) % theoretical ber

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  • Compression algorithm for IEEE-754 data

    - by David Taylor
    Anyone have a recommendation on a good compression algorithm that works well with double precision floating point values? We have found that the binary representation of floating point values results in very poor compression rates with common compression programs (e.g. Zip, RAR, 7-Zip etc). The data we need to compress is a one dimensional array of 8-byte values sorted in monotonically increasing order. The values represent temperatures in Kelvin with a span typically under of 100 degrees. The number of values ranges from a few hundred to at most 64K. Clarifications All values in the array are distinct, though repetition does exist at the byte level due to the way floating point values are represented. A lossless algorithm is desired since this is scientific data. Conversion to a fixed point representation with sufficient precision (~5 decimals) might be acceptable provided there is a significant improvement in storage efficiency. Update Found an interesting article on this subject. Not sure how applicable the approach is to my requirements. http://users.ices.utexas.edu/~burtscher/papers/dcc06.pdf

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  • IEEE SRS documents: lightweight version when working with outside contractors?

    - by maple_shaft
    Typically we follow an Agile development process that tends not to put an emphasis on writing requirements and technical documents that nobody will read. We tend to focus our limited manpower to development and testing activities with collaborative design and whiteboarding as a key focus. There is a mostly standalone web component that will take quite a few weeks to develop, but this work can be mostly parallel with other project work going on. To try and catch up time I was given a budget for hiring a developer on oDesk to complete this work. While my team isn't accustomed to working off of a firm SRS document, I realize that with outsourced development that it is a good idea to be as firm and specific as possible so I realize that I need to provide a detailed Requirements and Technical Specification document for this work to be done correctly. When I do write a Requirements document I typically utilize the standard IEEE SRS document template but I think this is too verbose and probably overkill for what I need to communicate to a developer. Is there another requirements document that is more lightweight and also accepted by a major standards organization like the IEEE? Further, as what will be developed as a software module that will interact with other software modules, my requirements really need to delve into technical specifications for things to work correctly. In this scenario does it make sense to merge technical and requirements specifications into a single document, and if not, what is a viable alternative?

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  • Fast sign in C++ float...are there any platform dependencies in this code?

    - by Patrick Niedzielski
    Searching online, I have found the following routine for calculating the sign of a float in IEEE format. This could easily be extended to a double, too. // returns 1.0f for positive floats, -1.0f for negative floats, 0.0f for zero inline float fast_sign(float f) { if (((int&)f & 0x7FFFFFFF)==0) return 0.f; // test exponent & mantissa bits: is input zero? else { float r = 1.0f; (int&)r |= ((int&)f & 0x80000000); // mask sign bit in f, set it in r if necessary return r; } } (Source: ``Fast sign for 32 bit floats'', Peter Schoffhauzer) I am weary to use this routine, though, because of the bit binary operations. I need my code to work on machines with different byte orders, but I am not sure how much of this the IEEE standard specifies, as I couldn't find the most recent version, published this year. Can someone tell me if this will work, regardless of the byte order of the machine? Thanks, Patrick

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  • Reading a Windows 'binary' float into a ASP jscript variable

    - by user89691
    I need to read files produced by a legacy Windows app that stores real numbers (the 8-byte "double" type) in binary - i.e. as a packed array of 8 bytes. I can read the 8 byte group OK but how can I present it to my ASP JScript code such I can get the real number back again. Or to put it another way: Say a file was produced by a Windows (Delphi) program: Assign (f, 'test.bin') ; rewrite (f, 1) ; r := 1234.56E78 ; BlockWrite (f, r, SizeOf (Double)) ; Close (f) ; Inspection of the file will show it contains 8 bytes, being: 94 0E 4C CA C2 97 AD 53 which is the real number in IEEE format. Assuming I can read these 8 bytes back in ASP, is there a simple way of getting the real number back again?

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  • is memset(ary,0,length) a portable way of inputting zero in double array

    - by monkeyking
    The following code uses memset to set all the bits to zero #include <iostream> #include <cstring> int main(){ int length = 5; double *array = new double[length]; memset(array,0,sizeof(double)*length); for(int i=0;i<length;i++) if(array[i]!=0.0) std::cerr<< "not zero in: " <<i <<std::endl; return 0; } Can I assume that this will work on all platforms? Does the double datatype always correspond to the ieee-754 standard? thanks

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