WhiteBlaze Pages 2024
A Complete Appalachian Trail Guidebook.
AVAILABLE NOW. $4 for interactive PDF(smartphone version)
Read more here WhiteBlaze Pages Store

Page 1 of 2 1 2 LastLast
Results 1 to 20 of 33
  1. #1
    Registered User neo's Avatar
    Join Date
    06-16-2004
    Location
    nashville,tn
    Age
    65
    Posts
    4,177
    Images
    337

    Default laplace transforms

    has any body ever did a calculated model of a potential hike using laplace transforms neo

  2. #2
    Registered User rambunny's Avatar
    Join Date
    09-04-2002
    Location
    Atkins Virginia
    Age
    70
    Posts
    356

    Default

    What the hey! Are you an engineer or something-hike don't analaze don't check milage-sleep under the stars where you drop. It's the journey!!!!

  3. #3
    Registered User Stoker53's Avatar
    Join Date
    02-15-2005
    Location
    Austin, TX.
    Age
    70
    Posts
    351

    Default

    Quote Originally Posted by rambunny
    What the hey! Are you an engineer or something-hike don't analaze don't check milage-sleep under the stars where you drop. It's the journey!!!!
    Perhaps Neo's journey is different from yours?
    "In the abundance of water the fool is thirsty."...Bob Marley

  4. #4
    2.17% and counting
    Join Date
    10-02-2003
    Location
    Silver Spring, MD
    Age
    43
    Posts
    254
    Images
    11

    Default

    Hmmm...

    So what exactly would you take the LaPlace transform of? I have to assume it would be something in the time domain. Perhaps velocity?

    Or were you implying you would be calculating the gravitational potential of a hike over some distance or time?

    Either way, I think the answer is a resounding NO. But if someone can spend their time using a large fluid dynamic finite element model to determine exactly why the shower curtain tends to billow inward in the shower, I'd say go for it. Heck, publish the results.

  5. #5
    Registered User neo's Avatar
    Join Date
    06-16-2004
    Location
    nashville,tn
    Age
    65
    Posts
    4,177
    Images
    337

  6. #6

    Default

    I thought "The Place" had transformed!

    By the way, what is that mathematical formula representing?

  7. #7
    2.17% and counting
    Join Date
    10-02-2003
    Location
    Silver Spring, MD
    Age
    43
    Posts
    254
    Images
    11

    Default

    The Laplace transform transforms a real-valued function into a function of a complex variable.

    In engineering Laplace transforms allow you to take differential equation in the time domain and transform it into an algebraic equation in the Laplace domain. All of this is of course subject to certian conditions. The function must be linear (exhibits superposition and homogeneity).

    In my field this is often done to make solving the equation much easier. Also plotting the results in the laplace domain often makes it much easier to analyze dynamic systems (vibration and control theory).

  8. #8
    Section Hiker 350 miles DebW's Avatar
    Join Date
    09-10-2002
    Location
    Boston area
    Age
    68
    Posts
    690
    Images
    55

    Default

    Not LaPlace transforms, but there's an old thread (under general AT polls) here about apparent pack weight vs hiking time where I thought about mathematical relationships in hiking. I was going to construct functional relationships between apparent pack weight and various independent variables and publish in the Journal of Irreproducable Results. Here's a repeat of my idea from that thread:

    .............
    This poll was inspired by my 2 week hike of Vermont in 2001 with a load that was too heavy and a pack that didn't support it well. I began to think of all the variables that could affect my perceived pack weight (time of day, temperature, trail grade, trail condition, time since rest stop, time since eating, etc. ) and how they were functionally related to it (linear, log, exponential, power law). Then I thought that maybe I could put all of this into mathematics and publish it in the "Journal of Irreproducable Results". I could graph my actual pack weight and apparent pack weight as a function of time over the course of the 2 week hike, correlate this with a set of independent variables (temperature, trail grade, etc.), and develop the functional relations. Actually, I was going to take the backwards approach of making up appropriate functional relationships first, then calculation apparent pack weight from actual pack weight, and adding random "noise" so that my pseudoscience looked more realistic. Now you know what scientists think about while hiking.

    Anyone want to suggest some functional relationships? I'll make you a co-author of the study. I figure that "time since last rest" should be exponential. "Trail grade" should be a 2nd order quadratic because very steep downhills can be as hard as very steep uphills. Rock, you've given me a new independent variable "time since start of hike" - I think it should be an inverse exponential.

  9. #9
    Registered User neo's Avatar
    Join Date
    06-16-2004
    Location
    nashville,tn
    Age
    65
    Posts
    4,177
    Images
    337

    Default

    Quote Originally Posted by DebW
    Not LaPlace transforms, but there's an old thread (under general AT polls) here about apparent pack weight vs hiking time where I thought about mathematical relationships in hiking. I was going to construct functional relationships between apparent pack weight and various independent variables and publish in the Journal of Irreproducable Results. Here's a repeat of my idea from that thread:

    .............
    This poll was inspired by my 2 week hike of Vermont in 2001 with a load that was too heavy and a pack that didn't support it well. I began to think of all the variables that could affect my perceived pack weight (time of day, temperature, trail grade, trail condition, time since rest stop, time since eating, etc. ) and how they were functionally related to it (linear, log, exponential, power law). Then I thought that maybe I could put all of this into mathematics and publish it in the "Journal of Irreproducable Results". I could graph my actual pack weight and apparent pack weight as a function of time over the course of the 2 week hike, correlate this with a set of independent variables (temperature, trail grade, etc.), and develop the functional relations. Actually, I was going to take the backwards approach of making up appropriate functional relationships first, then calculation apparent pack weight from actual pack weight, and adding random "noise" so that my pseudoscience looked more realistic. Now you know what scientists think about while hiking.

    Anyone want to suggest some functional relationships? I'll make you a co-author of the study. I figure that "time since last rest" should be exponential. "Trail grade" should be a 2nd order quadratic because very steep downhills can be as hard as very steep uphills. Rock, you've given me a new independent variable "time since start of hike" - I think it should be an inverse exponential.
    you may want to consider using fourier transforms neo

  10. #10
    Registered User neo's Avatar
    Join Date
    06-16-2004
    Location
    nashville,tn
    Age
    65
    Posts
    4,177
    Images
    337

    Default

    Quote Originally Posted by neo
    you may want to consider using fourier transforms neo
    http://mathworld.wolfram.com/FourierTransform.html

  11. #11
    Registered User The Cheat's Avatar
    Join Date
    12-06-2004
    Location
    Poughkeepsie, NY
    Age
    61
    Posts
    336

    Default

    TYOL

    Transform Your Own Laplace

  12. #12

    Default

    Time since last rest stop as a sinesoidal relationship, as it will oscillate, along with time since last eating event modeled similarly. You might model grade as absolute value of grade, but this assumes that the subject considers the ups and downs similarly. A quadratic function is a good choice. Also, consider throwing in some categorical variables, like weather for instance.

  13. #13
    American Idiot
    Join Date
    05-27-2004
    Location
    Seattle, WA
    Age
    54
    Posts
    1,045
    Images
    3

    Default

    Geez, now would be a good time to read Rick the Lone Wolf's Boiling Springs entry on this mathematical stuff.
    How many more of our soldiers must die in Iraq?

  14. #14
    Registered User
    Join Date
    04-22-2005
    Location
    Wilmington, Delaware
    Age
    60
    Posts
    25

    Default

    Quote Originally Posted by Alligator
    Time since last rest stop as a sinesoidal relationship, as it will oscillate, along with time since last eating event modeled similarly. You might model grade as absolute value of grade, but this assumes that the subject considers the ups and downs similarly. A quadratic function is a good choice. Also, consider throwing in some categorical variables, like weather for instance.
    Just remember:

    L'Hôpital Rule's



  15. #15
    Registered Loser c.coyle's Avatar
    Join Date
    07-18-2003
    Location
    PA - Near 501 Shelter
    Posts
    774
    Images
    103

    Default

    Quote Originally Posted by neo
    has any body ever did a calculated model of a potential hike using laplace transforms neo
    Why, yes. As a matter of fact, I have. As a public service to the hiking community, I have posted a summary here.

    As you can see, this conclusively proves that an extra pound on your feet is, believe it or not, equivalent to removing 3.1415926535 pounds from your pack (assuming, of course, it has an external frame).

  16. #16
    Registered User
    Join Date
    04-22-2005
    Location
    Wilmington, Delaware
    Age
    60
    Posts
    25

    Default Is that cake? Or pie?

    Quote Originally Posted by c.coyle
    Why, yes. As a matter of fact, I have. As a public service to the hiking community, I have posted a summary here.

    As you can see, this conclusively proves that an extra pound on your feet is, believe it or not, equivalent to removing 3.1415926535 pounds from your pack (assuming, of course, it has an external frame).
    All I see is a proof that the area under the curve of a unit impulse is equal to 1. Neo, you can't have your pi and eat it too!

  17. #17

    Default

    Quote Originally Posted by lobster
    By the way, what is that mathematical formula representing?
    It's the recipe for Krispy Kreme donuts, you silly crustacean.
    'All my lies are always wishes" ~Jeff Tweedy~

  18. #18
    Registered User
    Join Date
    04-22-2005
    Location
    Wilmington, Delaware
    Age
    60
    Posts
    25

    Default Oh no!

    Quote Originally Posted by MOWGLI16
    It's the recipe for Krispy Kreme donuts, you silly crustacean.
    Now the secret's out. So much for trying to obfuscate the true and hidden meaning of the sacred, halowed Krispy Things with silly mathematical blather ...

  19. #19
    Registered User Stoker53's Avatar
    Join Date
    02-15-2005
    Location
    Austin, TX.
    Age
    70
    Posts
    351

    Default

    This thread has me totally lost and ROTFLMAO.
    "In the abundance of water the fool is thirsty."...Bob Marley

  20. #20

    Default

    When in doubt, get a French Mathematician!

Page 1 of 2 1 2 LastLast
++ New Posts ++

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •