Search Results

Search found 254 results on 11 pages for 'hopes'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 11/11 | < Previous Page | 7 8 9 10 11 

  • Masters vs. PhD - long [closed]

    - by Sterling
    I'm 21 years old and a first year master's computer science student. Whether or not to continue with my PhD has been plaguing me for the past few months. I can't stop thinking about it and am extremely torn on the issue. I have read http://www.cs.unc.edu/~azuma/hitch4.html and many, many other masters vs phd articles on the web. Unfortunately, I have not yet come to a conclusion. I was hoping that I could post my ideas about the issue on here in hopes to 1) get some extra insight on the issue and 2) make sure that I am correct in my assumptions. Hopefully having people who have experience in the respective fields can tell me if I am wrong so I don't make my decision based on false ideas. Okay, to get this topic out of the way - money. Money isn't the most important thing to me, but it is still important. It's always been a goal of mine to make 6 figures, but I realize that will probably take me a long time with either path. According to most online salary calculating sites, the average starting salary for a software engineer is ~60-70k. The PhD program here is 5 years, so that's about 300k I am missing out on by not going into the workforce with a masters. I have only ever had ~1k at one time in my life so 300k is something I can't even really accurately imagine. I know that I wouldn't have at once obviously, but just to know I would be earning that is kinda crazy to me. I feel like I would be living quite comfortably by the time I'm 30 years old (but risk being too content too soon). I would definitely love to have at least a few years of my 20s to spend with that kind of money before I have a family to spend it all on. I haven't grown up very financially stable so it would be so nice to just spend some money…get a nice car, buy a new guitar or two, eat some good food, and just be financially comfortable. I have always felt like I deserved to make good money in my life, even as a kid growing up, and I just want to have it be a reality. I know that either path I take will make good money by the time I'm ~40-45 years old, but I guess I'm just sick of not making money and am getting impatient about it. However, a big idea pushing me towards a PhD is that I feel the masters path would give me a feeling of selling out if I have the capability to solve real questions in the computer science world. (pretty straight-forward - not much to elaborate on, but this is a big deal) Now onto other aspects of the decision. I originally got into computer science because of programming. I started in high school and knew very soon that it was what I wanted to do for a career. I feel like getting a masters and being a software engineer in the industry gives me much more time to program in my career. In research, I feel like I would spend more time reading, writing, trying to get grant money, etc than I would coding. A guy I work with in the lab just recently published a paper. He showed it to me and I was shocked by it. The first two pages was littered with equations and formulas. Then the next page or so was followed by more equations and formulas that he derived from the previous ones. That was his work - breaking down and creating all of these formulas for robotic arm movement. And whenever I read computer science papers, they all seem to follow this pattern. I always pictured myself coding all day long…not proving equations and things of that nature. I know that's only one part of computer science research, but that part bores me. A couple cons on each side - Phd - I don't really enjoy writing or feel like I'm that great at technical writing. Whenever I'm in groups to make something, I'm always the one who does the large majority of the work and then give it to my team members to write up a report. Presenting is different though - I don't mind presenting at all as long as I have a good grasp on what I am presenting. But writing papers seems like such a chore to me. And because of this, the "publish or perish" phrase really turns me off from research. Another bad thing - I feel like if I am doing research, most of it would be done alone. I work best in small groups. I like to have at least one person to bounce ideas off of when I am brainstorming. The idea of being a part of some small elite group to build things sounds ideal to me. So being able to work in small groups for the majority of my career is a definite plus. I don't feel like I can get this doing research. Masters - I read a lot online that most people come in as engineers and eventually move into management positions. As of now, I don't see myself wanting to be a part of management. Lets say my company wanted to make some new product or system - I would get much more pride, enjoyment, and overall satisfaction to say "I made this" rather than "I managed a group of people that made this." I want to be a big part of the development process. I want to make things. I think it would be great to be more specialized than other people. I would rather know everything about something than something about everything. I always have been that way - was a great pitcher during my baseball years, but not so good at everything else, great at certain classes in school, but not so good at others, etc. To think that my career would be the same way sounds okay to me. Getting a PhD would point me in this direction. It would be great to be some guy who is someone that people look towards and come to ask for help because of being such an important contributor to a very specific field, such as artificial neural networks or robotic haptic perception. From what I gather about the software industry, being specialized can be a very bad thing because of the speed of the new technology. I When it comes to being employed, I have pretty conservative views. I don't want to change companies every 5 years. Maybe this is something everyone wishes, but I would love to just be an important person in one company for 10+ (maybe 20-25+ if I'm lucky!) years if the working conditions were acceptable. I feel like that is more possible as a PhD though, being a professor or researcher. The more I read about people in the software industry, the more it seems like most software engineers bounce from company to company at rapid paces. Some even work like a hired gun from project to project which is NOT what I want AT ALL. But finding a place to make great and important software would be great if that actually happens in the real world. I'm a very competitive person. I thrive on competition. I don't really know why, but I have always been that way even as a kid growing up. Competition always gave me a reason to practice that little extra every night, always push my limits, etc. It seems to me like there is no competition in the research world. It seems like everyone is very relaxed as long as research is being conducted. The only competition is if someone is researching the same thing as you and its whoever can finish and publish first (but everyone seems to careful to check that circumstance). The only noticeable competition to me is just with yourself and your own discipline. I like the idea that in the industry, there is real competition between companies to put out the best product or be put out of business. I feel like this would constantly be pushing me to be better at what I do. One thing that is really pushing me towards a PhD is the lifetime of the things you make. I feel like if you make something truly innovative in the industry…just some really great new application or system…there is a shelf-life of about 5-10 years before someone just does it faster and more efficiently. But with research work, you could create an idea or algorithm that last decades. For instance, the A* search algorithm was described in 1968 and is still widely used today. That is amazing to me. In the words of Palahniuk, "The goal isn't to live forever, its to create something that will." Over anything, I just want to do something that matters. I want my work to help and progress society. Seriously, if I'm stuck programming GUIs for the next 40 years…I might shoot myself in the face. But then again, I hate the idea that less than 1% of the population will come into contact with my work and even less understand its importance. So if anything I have said is false then please inform me. If you think I come off as a masters or PhD, inform me. If you want to give me some extra insight or add on to any point I made, please do. Thank you so much to anyone for any help.

    Read the article

  • How to do MVC the right way

    - by Ieyasu Sawada
    I've been doing MVC for a few months now using the CodeIgniter framework in PHP but I still don't know if I'm really doing things right. What I currently do is: Model - this is where I put database queries (select, insert, update, delete). Here's a sample from one of the models that I have: function register_user($user_login, $user_profile, $department, $role) { $department_id = $this->get_department_id($department); $role_id = $this->get_role_id($role); array_push($user_login, $department_id, $role_id); $this->db->query("INSERT INTO tbl_users SET username=?, hashed_password=?, salt=?, department_id=?, role_id=?", $user_login); $user_id = $this->db->insert_id(); array_push($user_profile, $user_id); $this->db->query(" INSERT INTO tbl_userprofile SET firstname=?, midname=?, lastname=?, user_id=? ", $user_profile); } Controller - talks to the model, calls up the methods in the model which queries the database, supplies the data which the views will display(success alerts, error alerts, data from database), inherits a parent controller which checks if user is logged in. Here's a sample: function create_user(){ $this->load->helper('encryption/Bcrypt'); $bcrypt = new Bcrypt(15); $user_data = array( 'username' => 'Username', 'firstname' => 'Firstname', 'middlename' => 'Middlename', 'lastname' => 'Lastname', 'password' => 'Password', 'department' => 'Department', 'role' => 'Role' ); foreach ($user_data as $key => $value) { $this->form_validation->set_rules($key, $value, 'required|trim'); } if ($this->form_validation->run() == FALSE) { $departments = $this->user_model->list_departments(); $it_roles = $this->user_model->list_roles(1); $tc_roles = $this->user_model->list_roles(2); $assessor_roles = $this->user_model->list_roles(3); $data['data'] = array('departments' => $departments, 'it_roles' => $it_roles, 'tc_roles' => $tc_roles, 'assessor_roles' => $assessor_roles); $data['content'] = 'admin/create_user'; parent::error_alert(); $this->load->view($this->_at, $data); } else { $username = $this->input->post('username'); $salt = $bcrypt->getSalt(); $hashed_password = $bcrypt->hash($this->input->post('password'), $salt); $fname = $this->input->post('firstname'); $mname = $this->input->post('middlename'); $lname = $this->input->post('lastname'); $department = $this->input->post('department'); $role = $this->input->post('role'); $user_login = array($username, $hashed_password, $salt); $user_profile = array($fname, $mname, $lname); $this->user_model->register_user($user_login, $user_profile, $department, $role); $data['content'] = 'admin/view_user'; parent::success_alert(4, 'User Sucessfully Registered!', 'You may now login using your account'); $data['data'] = array('username' => $username, 'fname' => $fname, 'mname' => $mname, 'lname' => $lname, 'department' => $department, 'role' => $role); $this->load->view($this->_at, $data); } } Views - this is where I put html, css, and JavaScript code (form validation code for the current form, looping through the data supplied by controller, a few if statements to hide and show things depending on the data supplied by the controller). <!--User registration form--> <form class="well min-form" method="post"> <div class="form-heading"> <h3>User Registration</h3> </div> <label for="username">Username</label> <input type="text" id="username" name="username" class="span3" autofocus> <label for="password">Password</label> <input type="password" id="password" name="password" class="span3"> <label for="firstname">First name</label> <input type="text" id="firstname" name="firstname" class="span3"> <label for="middlename">Middle name</label> <input type="text" id="middlename" name="middlename" class="span3"> <label for="lastname">Last name</label> <input type="text" id="lastname" name="lastname" class="span3"> <label for="department">Department</label> <input type="text" id="department" name="department" class="span3" list="list_departments"> <datalist id="list_departments"> <?php foreach ($data['departments'] as $row) { ?> <option data-id="<?php echo $row['department_id']; ?>" value="<?php echo $row['department']; ?>"><?php echo $row['department']; ?></option> <?php } ?> </datalist> <label for="role">Role</label> <input type="text" id="role" name="role" class="span3" list=""> <datalist id="list_it"> <?php foreach ($data['it_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <datalist id="list_collection"> <?php foreach ($data['tc_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <datalist id="list_assessor"> <?php foreach ($data['assessor_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <p> <button type="submit" class="btn btn-success">Create User</button> </p> </form> <script> var departments = []; var roles = []; $('#list_departments option').each(function(i){ departments[i] = $(this).val(); }); $('#list_it option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#list_collection option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#list_assessor option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#department').blur(function(){ var department = $.trim($(this).val()); $('#role').attr('list', 'list_' + department); }); var password = new LiveValidation('password'); password.add(Validate.Presence); password.add(Validate.Length, {minimum: 10}); $('input[type=text]').each(function(i){ var field_id = $(this).attr('id'); var field = new LiveValidation(field_id); field.add(Validate.Presence); if(field_id == 'department'){ field.add(Validate.Inclusion, {within : departments}); } else if(field_id == 'role'){ field.add(Validate.Inclusion, {within : roles}) } }); </script> The codes above are actually code from the application that I'm currently working on. I'm working on it alone so I don't really have someone to review my code for me and point out the wrong things in it so I'm posting it here in hopes that someone could point out the wrong things that I've done in here. I'm also looking for some guidelines in writing MVC code like what are the things that should be and shouldn't be included in views, models and controllers. How else can I improve the current code that I have right now. I've written some really terrible code before(duplication of logic, etc.) that's why I want to improve my code so that I can easily maintain it in the future. Thanks!

    Read the article

  • Grub 'Read Error' - Only Loads with LiveCD

    - by Ryan Sharp
    Problem After installing Ubuntu to complete my Windows 7/Ubuntu 12.04 dual-boot setup, Grub just wouldn't load at all unless I boot from the LiveCD. Afterwards, everything works completely normal. However, this workaround isn't a solution and I'd like to be able to boot without the aid of a disc. Fdisk -l Using the fdisk -l command, I am given the following: Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x324971d1 Device Boot Start End Blocks Id System /dev/sda1 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 208896 48957439 24374272 7 HPFS/NTFS/exFAT /dev/sda3 * 48959486 124067839 37554177 5 Extended /dev/sda5 48959488 124067839 37554176 83 Linux Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc0ee6a69 Device Boot Start End Blocks Id System /dev/sdb1 1024208894 1953523711 464657409 5 Extended /dev/sdb3 * 2048 1024206847 512102400 7 HPFS/NTFS/exFAT /dev/sdb5 1024208896 1937897471 456844288 83 Linux /dev/sdb6 1937899520 1953523711 7812096 82 Linux swap / Solaris Partition table entries are not in disk order Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x292eee23 Device Boot Start End Blocks Id System /dev/sdc1 2048 625141759 312569856 7 HPFS/NTFS/exFAT Bootinfoscript I've used the BootInfoScript, and received the following output: Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Windows is installed in the MBR of /dev/sdc. sda1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /Boot/BCD sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda3: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown Boot sector info: sda5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb1: __________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Boot files: sdb6: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: sdb3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sdb3 starts at sector 200744960. But according to the info from fdisk, sdb3 starts at sector 2048. According to the info in the boot sector, sdb3 has 823461887 sectors, but according to the info from fdisk, it has 1024204799 sectors. Operating System: Boot files: sdc1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 2,048 206,847 204,800 7 NTFS / exFAT / HPFS /dev/sda2 208,896 48,957,439 48,748,544 7 NTFS / exFAT / HPFS /dev/sda3 * 48,959,486 124,067,839 75,108,354 5 Extended /dev/sda5 48,959,488 124,067,839 75,108,352 83 Linux Drive: sdb _____________________________________________________________________ Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdb1 1,024,208,894 1,953,523,711 929,314,818 5 Extended /dev/sdb5 1,024,208,896 1,937,897,471 913,688,576 83 Linux /dev/sdb6 1,937,899,520 1,953,523,711 15,624,192 82 Linux swap / Solaris /dev/sdb3 * 2,048 1,024,206,847 1,024,204,800 7 NTFS / exFAT / HPFS Drive: sdc _____________________________________________________________________ Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdc1 2,048 625,141,759 625,139,712 7 NTFS / exFAT / HPFS "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/sda1 A48056DF8056B80E ntfs System Reserved /dev/sda2 A8C6D6A4C6D671D4 ntfs Windows /dev/sda5 fd71c537-3715-44e1-b1fe-07537e22b3dd ext4 /dev/sdb3 6373D03D0A3747A8 ntfs Steam /dev/sdb5 6f5a6eb3-a932-45aa-893e-045b57708270 ext4 /dev/sdb6 469848c8-867a-41b7-b0e1-b813a43c64af swap /dev/sdc1 725D7B961CF34B1B ntfs backup ================================ Mount points: ================================= Device Mount_Point Type Options /dev/sda5 / ext4 (rw,noatime,nodiratime,discard,errors=remount-ro) /dev/sdb5 /home ext4 (rw) =========================== sda5/boot/grub/grub.cfg: =========================== -------------------------------------------------------------------------------- # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd set locale_dir=($root)/boot/grub/locale set lang=en_GB insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.2.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-29-generic } menuentry 'Ubuntu, with Linux 3.2.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd echo 'Loading Linux 3.2.0-29-generic ...' linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-29-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root A48056DF8056B80E chainloader +1 } menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root A8C6D6A4C6D671D4 chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda5/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda5 during installation UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd / ext4 noatime,nodiratime,discard,errors=remount-ro 0 1 # /home was on /dev/sdb5 during installation UUID=6f5a6eb3-a932-45aa-893e-045b57708270 /home ext4 defaults 0 2 # swap was on /dev/sdb6 during installation UUID=469848c8-867a-41b7-b0e1-b813a43c64af none swap sw 0 0 tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0 -------------------------------------------------------------------------------- =================== sda5: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) = boot/grub/core.img 1 = boot/grub/grub.cfg 1 = boot/initrd.img-3.2.0-29-generic 2 = boot/vmlinuz-3.2.0-29-generic 1 = initrd.img 2 = vmlinuz 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda3 00000000 63 6f 70 69 61 20 65 20 63 6f 6c 61 41 63 65 64 |copia e colaAced| 00000010 65 72 20 61 20 74 6f 64 6f 20 6f 20 74 65 78 74 |er a todo o text| 00000020 6f 20 66 61 6c 61 64 6f 20 75 74 69 6c 69 7a 61 |o falado utiliza| 00000030 6e 64 6f 20 61 20 63 6f 6e 76 65 72 73 c3 a3 6f |ndo a convers..o| 00000040 20 64 65 20 74 65 78 74 6f 20 70 61 72 61 20 76 | de texto para v| 00000050 6f 7a 4d 61 6e 69 70 75 6c 61 72 20 61 73 20 64 |ozManipular as d| 00000060 65 66 69 6e 69 c3 a7 c3 b5 65 73 20 71 75 65 20 |efini....es que | 00000070 63 6f 6e 74 72 6f 6c 61 6d 20 6f 20 61 63 65 73 |controlam o aces| 00000080 73 6f 20 64 65 20 57 65 62 73 69 74 65 73 20 61 |so de Websites a| 00000090 20 63 6f 6f 6b 69 65 73 2c 20 4a 61 76 61 53 63 | cookies, JavaSc| 000000a0 72 69 70 74 20 65 20 70 6c 75 67 2d 69 6e 73 4d |ript e plug-insM| 000000b0 61 6e 69 70 75 6c 61 72 20 61 73 20 64 65 66 69 |anipular as defi| 000000c0 6e 69 c3 a7 c3 b5 65 73 20 72 65 6c 61 63 69 6f |ni....es relacio| 000000d0 6e 61 64 61 73 20 63 6f 6d 20 70 72 69 76 61 63 |nadas com privac| 000000e0 69 64 61 64 65 41 63 65 64 65 72 20 61 6f 73 20 |idadeAceder aos | 000000f0 73 65 75 73 20 70 65 72 69 66 c3 a9 72 69 63 6f |seus perif..rico| 00000100 73 20 55 53 42 55 74 69 6c 69 7a 61 72 20 6f 20 |s USBUtilizar o | 00000110 73 65 75 20 6d 69 63 72 6f 66 6f 6e 65 55 74 69 |seu microfoneUti| 00000120 6c 69 7a 61 72 20 61 20 73 75 61 20 63 c3 a2 6d |lizar a sua c..m| 00000130 61 72 61 55 74 69 6c 69 7a 61 72 20 6f 20 73 65 |araUtilizar o se| 00000140 75 20 6d 69 63 72 6f 66 6f 6e 65 20 65 20 61 20 |u microfone e a | 00000150 63 c3 a2 6d 61 72 61 4e c3 a3 6f 20 66 6f 69 20 |c..maraN..o foi | 00000160 70 6f 73 73 c3 ad 76 65 6c 20 65 6e 63 6f 6e 74 |poss..vel encont| 00000170 72 61 72 20 6f 20 63 61 6d 69 6e 68 6f 20 61 62 |rar o caminho ab| 00000180 73 6f 6c 75 74 6f 20 70 61 72 61 20 6f 20 64 69 |soluto para o di| 00000190 72 65 63 74 c3 b3 72 69 6f 20 61 20 65 6d 70 61 |rect..rio a empa| 000001a0 63 6f 74 61 72 2e 4f 20 64 69 72 65 63 74 c3 b3 |cotar.O direct..| 000001b0 72 69 6f 20 64 65 20 65 6e 74 72 61 64 61 00 fe |rio de entrada..| 000001c0 ff ff 83 fe ff ff 02 00 00 00 00 10 7a 04 00 00 |............z...| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 =============================== StdErr Messages: =============================== xz: (stdin): Compressed data is corrupt xz: (stdin): Compressed data is corrupt awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in Begging / Appreciation ;) If anything else is required to solve my problem, please ask. My only hopes are that I can solve this, and that doing so won't require re-installation of Grub due to how complicated the procedures are, or that I would be needed to reinstall the OS', as I have done so about six times already since friday due to several other issues I've encountered. Thank you, and good day. System Ubuntu 12.04 64-bit / Windows 7 SP1 64-bit 64GB SSD as boot/OS drive, 1TB HDD as /Home Swap and Steam drive.

    Read the article

  • Conceal packet loss in PCM stream

    - by ZeroDefect
    I am looking to use 'Packet Loss Concealment' to conceal lost PCM frames in an audio stream. Unfortunately, I cannot find a library that is accessible without all the licensing restrictions and code bloat (...up for some suggestions though). I have located some GPL code written by Steve Underwood for the Asterisk project which implements PLC. There are several limitations; although, as Steve suggests in his code, his algorithm can be applied to different streams with a bit of work. Currently, the code works with 8kHz 16-bit signed mono streams. Variations of the code can be found through a simple search of Google Code Search. My hope is that I can adapt the code to work with other streams. Initially, the goal is to adjust the algorithm for 8+ kHz, 16-bit signed, multichannel audio (all in a C++ environment). Eventually, I'm looking to make the code available under the GPL license in hopes that it could be of benefit to others... Attached is the code below with my efforts. The code includes a main function that will "drop" a number of frames with a given probability. Unfortunately, the code does not quite work as expected. I'm receiving EXC_BAD_ACCESS when running in gdb, but I don't get a trace from gdb when using 'bt' command. Clearly, I'm trampimg on memory some where but not sure exactly where. When I comment out the *amdf_pitch* function, the code runs without crashing... int main (int argc, char *argv[]) { std::ifstream fin("C:\\cc32kHz.pcm"); if(!fin.is_open()) { std::cout << "Failed to open input file" << std::endl; return 1; } std::ofstream fout_repaired("C:\\cc32kHz_repaired.pcm"); if(!fout_repaired.is_open()) { std::cout << "Failed to open output repaired file" << std::endl; return 1; } std::ofstream fout_lossy("C:\\cc32kHz_lossy.pcm"); if(!fout_lossy.is_open()) { std::cout << "Failed to open output repaired file" << std::endl; return 1; } audio::PcmConcealer Concealer; Concealer.Init(1, 16, 32000); //Generate random numbers; srand( time(NULL) ); int value = 0; int probability = 5; while(!fin.eof()) { char arr[2]; fin.read(arr, 2); //Generate's random number; value = rand() % 100 + 1; if(value <= probability) { char blank[2] = {0x00, 0x00}; fout_lossy.write(blank, 2); //Fill in data; Concealer.Fill((int16_t *)blank, 1); fout_repaired.write(blank, 2); } else { //Write data to file; fout_repaired.write(arr, 2); fout_lossy.write(arr, 2); Concealer.Receive((int16_t *)arr, 1); } } fin.close(); fout_repaired.close(); fout_lossy.close(); return 0; } PcmConcealer.hpp /* * Code adapted from Steve Underwood of the Asterisk Project. This code inherits * the same licensing restrictions as the Asterisk Project. */ #ifndef __PCMCONCEALER_HPP__ #define __PCMCONCEALER_HPP__ /** 1. What does it do? The packet loss concealment module provides a suitable synthetic fill-in signal, to minimise the audible effect of lost packets in VoIP applications. It is not tied to any particular codec, and could be used with almost any codec which does not specify its own procedure for packet loss concealment. Where a codec specific concealment procedure exists, the algorithm is usually built around knowledge of the characteristics of the particular codec. It will, therefore, generally give better results for that particular codec than this generic concealer will. 2. How does it work? While good packets are being received, the plc_rx() routine keeps a record of the trailing section of the known speech signal. If a packet is missed, plc_fillin() is called to produce a synthetic replacement for the real speech signal. The average mean difference function (AMDF) is applied to the last known good signal, to determine its effective pitch. Based on this, the last pitch period of signal is saved. Essentially, this cycle of speech will be repeated over and over until the real speech resumes. However, several refinements are needed to obtain smooth pleasant sounding results. - The two ends of the stored cycle of speech will not always fit together smoothly. This can cause roughness, or even clicks, at the joins between cycles. To soften this, the 1/4 pitch period of real speech preceeding the cycle to be repeated is blended with the last 1/4 pitch period of the cycle to be repeated, using an overlap-add (OLA) technique (i.e. in total, the last 5/4 pitch periods of real speech are used). - The start of the synthetic speech will not always fit together smoothly with the tail of real speech passed on before the erasure was identified. Ideally, we would like to modify the last 1/4 pitch period of the real speech, to blend it into the synthetic speech. However, it is too late for that. We could have delayed the real speech a little, but that would require more buffer manipulation, and hurt the efficiency of the no-lost-packets case (which we hope is the dominant case). Instead we use a degenerate form of OLA to modify the start of the synthetic data. The last 1/4 pitch period of real speech is time reversed, and OLA is used to blend it with the first 1/4 pitch period of synthetic speech. The result seems quite acceptable. - As we progress into the erasure, the chances of the synthetic signal being anything like correct steadily fall. Therefore, the volume of the synthesized signal is made to decay linearly, such that after 50ms of missing audio it is reduced to silence. - When real speech resumes, an extra 1/4 pitch period of sythetic speech is blended with the start of the real speech. If the erasure is small, this smoothes the transition. If the erasure is long, and the synthetic signal has faded to zero, the blending softens the start up of the real signal, avoiding a kind of "click" or "pop" effect that might occur with a sudden onset. 3. How do I use it? Before audio is processed, call plc_init() to create an instance of the packet loss concealer. For each received audio packet that is acceptable (i.e. not including those being dropped for being too late) call plc_rx() to record the content of the packet. Note this may modify the packet a little after a period of packet loss, to blend real synthetic data smoothly. When a real packet is not available in time, call plc_fillin() to create a sythetic substitute. That's it! */ /*! Minimum allowed pitch (66 Hz) */ #define PLC_PITCH_MIN(SAMPLE_RATE) ((double)(SAMPLE_RATE) / 66.6) /*! Maximum allowed pitch (200 Hz) */ #define PLC_PITCH_MAX(SAMPLE_RATE) ((SAMPLE_RATE) / 200) /*! Maximum pitch OLA window */ //#define PLC_PITCH_OVERLAP_MAX(SAMPLE_RATE) ((PLC_PITCH_MIN(SAMPLE_RATE)) >> 2) /*! The length over which the AMDF function looks for similarity (20 ms) */ #define CORRELATION_SPAN(SAMPLE_RATE) ((20 * (SAMPLE_RATE)) / 1000) /*! History buffer length. The buffer must also be at leat 1.25 times PLC_PITCH_MIN, but that is much smaller than the buffer needs to be for the pitch assessment. */ //#define PLC_HISTORY_LEN(SAMPLE_RATE) ((CORRELATION_SPAN(SAMPLE_RATE)) + (PLC_PITCH_MIN(SAMPLE_RATE))) namespace audio { typedef struct { /*! Consecutive erased samples */ int missing_samples; /*! Current offset into pitch period */ int pitch_offset; /*! Pitch estimate */ int pitch; /*! Buffer for a cycle of speech */ float *pitchbuf;//[PLC_PITCH_MIN]; /*! History buffer */ short *history;//[PLC_HISTORY_LEN]; /*! Current pointer into the history buffer */ int buf_ptr; } plc_state_t; class PcmConcealer { public: PcmConcealer(); ~PcmConcealer(); void Init(int channels, int bit_depth, int sample_rate); //Process a block of received audio samples. int Receive(short amp[], int frames); //Fill-in a block of missing audio samples. int Fill(short amp[], int frames); void Destroy(); private: int amdf_pitch(int min_pitch, int max_pitch, short amp[], int channel_index, int frames); void save_history(plc_state_t *s, short *buf, int channel_index, int frames); void normalise_history(plc_state_t *s); /** Holds the states of each of the channels **/ std::vector< plc_state_t * > ChannelStates; int plc_pitch_min; int plc_pitch_max; int plc_pitch_overlap_max; int correlation_span; int plc_history_len; int channel_count; int sample_rate; bool Initialized; }; } #endif PcmConcealer.cpp /* * Code adapted from Steve Underwood of the Asterisk Project. This code inherits * the same licensing restrictions as the Asterisk Project. */ #include "audio/PcmConcealer.hpp" /* We do a straight line fade to zero volume in 50ms when we are filling in for missing data. */ #define ATTENUATION_INCREMENT 0.0025 /* Attenuation per sample */ #if !defined(INT16_MAX) #define INT16_MAX (32767) #define INT16_MIN (-32767-1) #endif #ifdef WIN32 inline double rint(double x) { return floor(x + 0.5); } #endif inline short fsaturate(double damp) { if (damp > 32767.0) return INT16_MAX; if (damp < -32768.0) return INT16_MIN; return (short)rint(damp); } namespace audio { PcmConcealer::PcmConcealer() : Initialized(false) { } PcmConcealer::~PcmConcealer() { Destroy(); } void PcmConcealer::Init(int channels, int bit_depth, int sample_rate) { if(Initialized) return; if(channels <= 0 || bit_depth != 16) return; Initialized = true; channel_count = channels; this->sample_rate = sample_rate; ////////////// double min = PLC_PITCH_MIN(sample_rate); int imin = (int)min; double max = PLC_PITCH_MAX(sample_rate); int imax = (int)max; plc_pitch_min = imin; plc_pitch_max = imax; plc_pitch_overlap_max = (plc_pitch_min >> 2); correlation_span = CORRELATION_SPAN(sample_rate); plc_history_len = correlation_span + plc_pitch_min; ////////////// for(int i = 0; i < channel_count; i ++) { plc_state_t *t = new plc_state_t; memset(t, 0, sizeof(plc_state_t)); t->pitchbuf = new float[plc_pitch_min]; t->history = new short[plc_history_len]; ChannelStates.push_back(t); } } void PcmConcealer::Destroy() { if(!Initialized) return; while(ChannelStates.size()) { plc_state_t *s = ChannelStates.at(0); if(s) { if(s->history) delete s->history; if(s->pitchbuf) delete s->pitchbuf; memset(s, 0, sizeof(plc_state_t)); delete s; } ChannelStates.erase(ChannelStates.begin()); } ChannelStates.clear(); Initialized = false; } //Process a block of received audio samples. int PcmConcealer::Receive(short amp[], int frames) { if(!Initialized) return 0; int j = 0; for(int k = 0; k < ChannelStates.size(); k++) { int i; int overlap_len; int pitch_overlap; float old_step; float new_step; float old_weight; float new_weight; float gain; plc_state_t *s = ChannelStates.at(k); if (s->missing_samples) { /* Although we have a real signal, we need to smooth it to fit well with the synthetic signal we used for the previous block */ /* The start of the real data is overlapped with the next 1/4 cycle of the synthetic data. */ pitch_overlap = s->pitch >> 2; if (pitch_overlap > frames) pitch_overlap = frames; gain = 1.0 - s->missing_samples * ATTENUATION_INCREMENT; if (gain < 0.0) gain = 0.0; new_step = 1.0/pitch_overlap; old_step = new_step*gain; new_weight = new_step; old_weight = (1.0 - new_step)*gain; for (i = 0; i < pitch_overlap; i++) { int index = (i * channel_count) + j; amp[index] = fsaturate(old_weight * s->pitchbuf[s->pitch_offset] + new_weight * amp[index]); if (++s->pitch_offset >= s->pitch) s->pitch_offset = 0; new_weight += new_step; old_weight -= old_step; if (old_weight < 0.0) old_weight = 0.0; } s->missing_samples = 0; } save_history(s, amp, j, frames); j++; } return frames; } //Fill-in a block of missing audio samples. int PcmConcealer::Fill(short amp[], int frames) { if(!Initialized) return 0; int j =0; for(int k = 0; k < ChannelStates.size(); k++) { short *tmp = new short[plc_pitch_overlap_max]; int i; int pitch_overlap; float old_step; float new_step; float old_weight; float new_weight; float gain; short *orig_amp; int orig_len; orig_amp = amp; orig_len = frames; plc_state_t *s = ChannelStates.at(k); if (s->missing_samples == 0) { // As the gap in real speech starts we need to assess the last known pitch, //and prepare the synthetic data we will use for fill-in normalise_history(s); s->pitch = amdf_pitch(plc_pitch_min, plc_pitch_max, s->history + plc_history_len - correlation_span - plc_pitch_min, j, correlation_span); // We overlap a 1/4 wavelength pitch_overlap = s->pitch >> 2; // Cook up a single cycle of pitch, using a single of the real signal with 1/4 //cycle OLA'ed to make the ends join up nicely // The first 3/4 of the cycle is a simple copy for (i = 0; i < s->pitch - pitch_overlap; i++) s->pitchbuf[i] = s->history[plc_history_len - s->pitch + i]; // The last 1/4 of the cycle is overlapped with the end of the previous cycle new_step = 1.0/pitch_overlap; new_weight = new_step; for ( ; i < s->pitch; i++) { s->pitchbuf[i] = s->history[plc_history_len - s->pitch + i]*(1.0 - new_weight) + s->history[plc_history_len - 2*s->pitch + i]*new_weight; new_weight += new_step; } // We should now be ready to fill in the gap with repeated, decaying cycles // of what is in pitchbuf // We need to OLA the first 1/4 wavelength of the synthetic data, to smooth // it into the previous real data. To avoid the need to introduce a delay // in the stream, reverse the last 1/4 wavelength, and OLA with that. gain = 1.0; new_step = 1.0/pitch_overlap; old_step = new_step; new_weight = new_step; old_weight = 1.0 - new_step; for (i = 0; i < pitch_overlap; i++) { int index = (i * channel_count) + j; amp[index] = fsaturate(old_weight * s->history[plc_history_len - 1 - i] + new_weight * s->pitchbuf[i]); new_weight += new_step; old_weight -= old_step; if (old_weight < 0.0) old_weight = 0.0; } s->pitch_offset = i; } else { gain = 1.0 - s->missing_samples*ATTENUATION_INCREMENT; i = 0; } for ( ; gain > 0.0 && i < frames; i++) { int index = (i * channel_count) + j; amp[index] = s->pitchbuf[s->pitch_offset]*gain; gain -= ATTENUATION_INCREMENT; if (++s->pitch_offset >= s->pitch) s->pitch_offset = 0; } for ( ; i < frames; i++) { int index = (i * channel_count) + j; amp[i] = 0; } s->missing_samples += orig_len; save_history(s, amp, j, frames); delete [] tmp; j++; } return frames; } void PcmConcealer::save_history(plc_state_t *s, short *buf, int channel_index, int frames) { if (frames >= plc_history_len) { /* Just keep the last part of the new data, starting at the beginning of the buffer */ //memcpy(s->history, buf + len - plc_history_len, sizeof(short)*plc_history_len); int frames_to_copy = plc_history_len; for(int i = 0; i < frames_to_copy; i ++) { int index = (channel_count * (i + frames - plc_history_len)) + channel_index; s->history[i] = buf[index]; } s->buf_ptr = 0; return; } if (s->buf_ptr + frames > plc_history_len) { /* Wraps around - must break into two sections */ //memcpy(s->history + s->buf_ptr, buf, sizeof(short)*(plc_history_len - s->buf_ptr)); short *hist_ptr = s->history + s->buf_ptr; int frames_to_copy = plc_history_len - s->buf_ptr; for(int i = 0; i < frames_to_copy; i ++) { int index = (channel_count * i) + channel_index; hist_ptr[i] = buf[index]; } frames -= (plc_history_len - s->buf_ptr); //memcpy(s->history, buf + (plc_history_len - s->buf_ptr), sizeof(short)*len); frames_to_copy = frames; for(int i = 0; i < frames_to_copy; i ++) { int index = (channel_count * (i + (plc_history_len - s->buf_ptr))) + channel_index; s->history[i] = buf[index]; } s->buf_ptr = frames; return; } /* Can use just one section */ //memcpy(s->history + s->buf_ptr, buf, sizeof(short)*len); short *hist_ptr = s->history + s->buf_ptr; int frames_to_copy = frames; for(int i = 0; i < frames_to_copy; i ++) { int index = (channel_count * i) + channel_index; hist_ptr[i] = buf[index]; } s->buf_ptr += frames; } void PcmConcealer::normalise_history(plc_state_t *s) { short *tmp = new short[plc_history_len]; if (s->buf_ptr == 0) return; memcpy(tmp, s->history, sizeof(short)*s->buf_ptr); memcpy(s->history, s->history + s->buf_ptr, sizeof(short)*(plc_history_len - s->buf_ptr)); memcpy(s->history + plc_history_len - s->buf_ptr, tmp, sizeof(short)*s->buf_ptr); s->buf_ptr = 0; delete [] tmp; } int PcmConcealer::amdf_pitch(int min_pitch, int max_pitch, short amp[], int channel_index, int frames) { int i; int j; int acc; int min_acc; int pitch; pitch = min_pitch; min_acc = INT_MAX; for (i = max_pitch; i <= min_pitch; i++) { acc = 0; for (j = 0; j < frames; j++) { int index1 = (channel_count * (i+j)) + channel_index; int index2 = (channel_count * j) + channel_index; //std::cout << "Index 1: " << index1 << ", Index 2: " << index2 << std::endl; acc += abs(amp[index1] - amp[index2]); } if (acc < min_acc) { min_acc = acc; pitch = i; } } std::cout << "Pitch: " << pitch << std::endl; return pitch; } } P.S. - I must confess that digital audio is not my forte...

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 7 8 9 10 11