I Would Not Like to Have Worked For Frank Lloyd Wright

Posted on 17-February-2015 by mathscinotes

"Early in life I had to choose between honest arrogance and hypocritical humility. I chose the former and have seen no reason to change."

— Frank Lloyd Wright
Figure 1: Frank Lloyd Wright.

Figure 1: Frank Lloyd Wright.

Because my wife and I are designing a cabin to replace our hunting shack in northern Minnesota, we have been looking at various house designs. Many of the designs we have looked at show the influence of Frank Lloyd Wright, who was the most famous member of the Prairie School of architecture. I know that Frank Lloyd Wright (Figure 1) is considered America's greatest architect (according to American Institute of Architects, 1991), but I do not think I would have wanted to work for him.

I have read many stories of his extreme arrogance. Arrogance can be very difficult to tolerate. I consider myself to be fairly tolerant of arrogance − nature usually provides a healthy dose of humility in due time. For example, I once had a boss that believed that he could overcome theoretically unsolvable problems (e.g. metastability). Reality soon corrected his erroneous belief in a rather nasty way.

I believe that managers should take more than their share of the blame and less than their share of the credit. Such was not the case with Frank Lloyd Wright. Consider the following quote from Givers and Takers.

Wright success is described as being helped often by apprentices, yet rarely giving them any credit.  He required his apprentices to put his name on any work they completed to insure all recognition would be allocated to him.  At several points in his career he was abandoned by the architectural community and went years without work. The book cites these challenging intervals a result of his unwillingness to share the spotlight and recognize those who contributed to his success.

His family didn't even like him. Consider the following quote from the Orlando Sentinel.

An unloving father, Wright was often estranged from his children. "I have had the father feeling for a building, but I never had it for my children,'' Wright once remarked. Grandson Tim Wright calls him "an embarrassing relative'' and "a torment'' to the family.

Wright was also legendary for not paying his bills − he was known as "Slow Pay Frank" (Source).

But they are shunned by neighbours outraged in equal parts by their living in sin and "Slow Pay Frank's" perennial refusal to honour his debts. As one cook explains to Mamah as she tenders her resignation: "It's sinful, that's what it is. And sin and pay is one thing, but sin and no pay I just can't abide."

He even refused to pay his family members (Source).

While he worked for his father on the Imperial Hotel in Tokyo (1920), Frank Lloyd Wright's son, John, an architect, was instructed by his father to complete a set of six drawings, present them to the client, Viscount Inouye, and collect the fee for his father. John did as he was asked, kept his unpaid back pay, and sent the balance to his father, who was then in the United States. On receipt of the balance Frank Lloyd Wright sent his son a cable-wireless, firing him.

In addition to firing his son, he also "presented him with a list of the total amount of money that John had cost him over his entire life" (Source).

I always tell my sons that most of life's management lessons are negative − as when we see a manager doing something that we swear we will never do. Frank has provided me a few more negative lessons.

Posted in History of Science and Technology, Management | Comments Off on I Would Not Like to Have Worked For Frank Lloyd Wright

Designing an LED Backlight

Posted on 16-February-2015 by mathscinotes

"The only thing worse than training employees and losing them is to not train them and keep them."

— Zig Ziglar

Introduction

Figure 1: An Active LED Backlight.

Figure 1: An Active LED Backlight.

I was reading an application note by Texas Instruments yesterday on how to design an LED backlight for an LCD display (Figure 1). The article was interesting, but it did bother me because it  presented a rather involved formula and did not provided any motivation for the formula, a derivation, or even definitions of the parameters used in the formula.

Equation 1 shows the formula that bothered me. I will provide a derivation, definitions for all the parameters, and a worked example.

Eq. 1

The principles behind designing LED backlight systems are fairly straightforward. However, Equation 1 looks rather complicated. Using basic physics, we can derive Equation 1 using a few basic principles. In the process of working through the derivation, we will acquire some insight into critical factors behind LED backlight designs.

Background

Backlight Basics

At the risk of grossly oversimplifying LED backlights, there are two basic types:

  • Lit from the side

    LEDs are mounted on the side of the display, which the advantage of giving you a very thin display. Unfortunately, the side backlighting can be uneven. Figure 2 shows an example of how this type of display is constructed.

    Figure M: Side-Mounted LEDs.

    Figure 2: Side-Mounted LEDs.

  • Lit from the back

    The LEDs are mounted directly behind the display. This approach gives more even lighting, but requires a thicker display. Figure 3 shows an example of how this type of display is constructed.

    Figure M: Lit from Behind Display Construction.

    Figure 3: Lit from Behind Display Construction.

Approach

Like most engineering calculations, backlight design is a form of budget calculation − so much light in, so much light out minus any losses. The process for this calculation is as follow:

  • Determine the amount of backlight you need from the display for your application.
  • Estimate the amount of loss the light will experience between the display and LEDs.
  • Compute the total amount of light you need from the LEDs.
  • Knowing the total amount of light needed, you can estimate the number of LEDs needed based on the type of LED you are using.

Definitions

Aspect Ratio (AR)
The aspect ratio of an image describes the relationship between its width and its height.It is commonly expressed as two numbers separated by a colon, as in 16:9. Sometimes the ratio is expressed in terms of pixel counts. For example, standard HDTV's aspect ratio could be expressed as 1920:1080 instead of 16:9 (Wikipedia).
Luminous Flux (ΦV)
In photometry, luminous flux or luminous power is the measure of the perceived power of light (Wikipedia).
Display Size (LS)
Displays are usually specified in terms of their diagonal measurement. To obtain an actual length and width, you need both the display size and the aspect ratio.
VDisp
The fraction of light lost between the LEDs and the display.
MV
The illuminance of the display. You can think of the illuminance as the luminous flux density.

Analysis

Intuitive Viewpoint

I derive a simple relationship for the number of LEDs required to generate a specified level of screen brightness in Figure 4.

Figure M: Intuitive Derivation of the Screen's Brightness.

Figure 4: Intuitive Derivation of the Screen's Brightness.

You can think of the the formula for the required number of LEDs as taking the total amount of light needed (A·MV) and dividing it by the effective amount of light per LED (KX·ΦV).

Screen Area

Display area is usually computed in terms of the display's diagonal length and its aspect area, which is not as intuitive as using the display's height and width. Figure 5 shows the formula for computing display area in terms of aspect ratio and diagonal length.

Figure M: Derivation of Screen Area Formula.

Figure 5: Derivation of Screen Area Formula.

LED Quantity Formula

Figure 6 shows the form of the display brightness formula in terms of the variables that I think in.

Figure 6: My Formula for the Number of LEDs Required.

Figure 6: My Formula for the Number of LEDs Required.

Equation 2 shows this equation using more conventional notation.

Eq. 2 \displaystyle {{N}_{{Min}}}=\left\lceil {\frac{AR}{{1+A{{R}^{2}}}}\cdot \frac{{{{M}_{V}}\cdot L_{S}^{2}}}{{{{\Phi }_{L}}\cdot {{K}_{{X}}}}}} \right\rceil

where

  • LS is the diagonal length of the screen.
  • MV is the required display luminosity.
  • ΦV is the luminous flux from a single LED.
  • KX is fraction of light that makes it from the LED to the display.
  • AR is the display aspect ratio.
  • \left\lceil {\text{ }} \right\rceil is the ceiling function.

Conversion to TI Form

My Equation 2 is the same as Equation 1 given the proper substitutions, which I show in Figure 7.

Figure M: Converting My Version to Equation 1 Form.

Figure 7: Converting My Version to Equation 1 Form.

Equation 1 has a constant called K that simply converts inches squared to meters squared \left( \text{m}^2 = 39.38^2 \cdot \text{in}^2 = 1550 \cdot \text{in}^2 \right). I just let Mathcad handle my unit conversions.

Simple Worked Example

Figure 8 shows a worked example using common parameter values.

Figure 8: Worked Example.

Figure 8: Worked Example.

Conclusion

When I first saw Equation 1, I could not understand it. Now that I have gone through the derivation, I understand every term. Since I find the form of Equation 1 non-intuitive, I will work with Equation 2.

Posted in Electronics, optics | 3 Comments

Bathroom Fan Selection

Posted on 1-February-2015 by mathscinotes

"If you have a talent, use it in every which way possible. Don't hoard it. Don't dole it out like a miser. Spend it lavishly like a millionaire intent on going broke."

- Brendan Francis

Introduction

Figure 1: Grille of My New Bathroom Fan.

Figure 1: Grille of My New Bathroom Fan.

I recently began remodeling a small bathroom on the second floor of my home. As you can imagine, talk of bathroom remodels leads to plumbing work, whether that means repairs or installing brand new fixtures. Having a professional plumber local to you (perhaps like this - makeitdrainplumbing.com/los-angeles-plumbing-services/) in your book of contacts is probably common sense so that you can get the people you need on the job right away. I have never been happy with the ventilation in that bathroom, particularly during showers when it seems more like a steam room than a bathroom. I was recommended by a friend for different ideas of where I could upgrade my HVAC system, for example with companies like JAK Services: AC Repair in Denton, however by that time I had already got a plan. Next time, I told them, I might have to give in and find help! But anyway, I decided to upgrade the ventilation fan in this room and I have been very happy with the improved performance. Figure 1 shows how the fan looks on my ceiling − yes, I am experimenting with a wood ceiling . In this post, I will go through my fan selection process and my ultimate choice.

Background

Definitions

Static Pressure (Ps)
Fan static pressure is simply the losses in the system downstream of the fan, including the system's exit loss to atmosphere. Static pressure is independent of the air velocity. It is usually measured by a pressure tap perpendicular to airflow. You can think of static pressure as the pressure that exists inside of a balloon.
Velocity pressure (Pv)
Velocity pressure is the pressure caused by air in motion – it is the pressure required to accelerate air from zero velocity to some velocity and is proportional to the kinetic energy of the air stream.. Velocity pressure cannot be measured directly, but can be calculated from the difference between the total pressure and static pressure. The velocity pressure is due entirely to the motion of the flow and depends upon the velocity and the density of the fluid.
Total Pressure (Pt)
Total pressure is the sum of the Static Pressure, Ps, and the Velocity Pressure, Pv, at a given cross section in a duct. A tube placed in a duct facing into the direction of the flow will measure the total pressure in the duct. If frictional losses are neglected, the mean total pressure at any cross section throughout the duct system is constant. You can measure total pressure using the apparatus shown in Figure 2. You can find more details on this device in the Wikipedia under pitot tube.

Figure M: Pitot Tube Setup.

Figure 2: Pitot Tube Setup.

Roof Jack
A roof jack is a device used to seal vent pipe protrusions from the roofing surface. It is important in HVAC design because it presents a resistance to the air flow. Making sure the air is flowing as intended is important. This is something that should be regualrly checked by a professional if you are not sure about anything. With this in mind, you may wish to visit a website like summersphc.com/anderson/services/cooling/ac-tune-up/ for more guidance.
Wall Cap
A wall cap is a device used to seal vent protrusions from a wall surface. It is important in HVAC design because it presents a resistance to the air flow. Another important decision to make is what kind of dosing pots are required before fitting the HVAC system.

Room Ventilation Basics

Requirements

The Home Ventilation Institute (HVI) recommends:

For bathrooms up to 100 square feet in area, HVI recommends that an exhaust fan provide 1 CFM [Cubic Feet Per Minute] per square foot (approximately eight air changes per hour) to properly ventilate the bathroom.

We can explain the "approximately air changes per hour" using the derivation shown in Figure 3. This derivation shows that the exact number of air changes per hour is 7.5, which everyone rounds up to 8.

Figure 2: Derivation of the Fan Rule of Thumb.

Figure 3: Derivation of the Fan Rule of Thumb.

My Bathroom

My bathroom is 11 feet long, 5.5 feet wide, and 8 feet tall. Using the 8 air-change per hour rule of thumb, we can compute the minimum ventilation rate required as shown in Figure 4.

Figure 3: Minimum Required Ventilation in Cubic Feet Per Minute.

Figure 4: Minimum Required Ventilation in Cubic Feet Per Minute.

Good Web Information Sources

There are numerous sources of good HVAC information on the web. I used the following pages.

Analysis

My analysis will follow the model used in this Stack Exchange response, which I found to be clear and to the point. For the purposes of my analysis, let's assume that my system will provide 90 CFM of air flow. I will then verify this assumption. If this assumptions is not correct, I will need to assume a difference air flow value and do the calculations again.

Equivalent Duct Length

The fan flow is a function of the path resistance to the air flow. All components in the system will be modeled as straight-duct length equivalences. The straight-duct length equivalences can be found in Appendix B. My system is pretty simple:

  • 4-inch diameter aluminum ducts.

    This is the diameter of PB110 inlet and outlet ports.

  • 15 feet of straight length.

    All resistances will be expressed in terms of equivalent straight-duct lengths.

  • one 90 elbow.

    The air resistance presented by a 90 elbow is often represented by 15 feet of straight duct length. I have seen other values used, but this is a common assumption.

  • a roof jack

    The air resistance of a roof jack is often modeled as equivalent to 30 feet of straight-duct.

For my bathroom ventilation system, the equivalent straight-duct length is 60 ft = 15 ft (straight run) + 30 ft (roof jack) + 15 ft (elbow).

We can use the chart in Appendix A to determine that 100-foot of 4-inch diameter duct carrying 90 CFM of air experiences a pressure drop of 0.58 inches of H20. This means that my 60-foot system will experience a pressure drop of 0.35 inches of H20 (=60 ft/100 ft 0.58 inches of H2O).

Candidate Fans

I have installed about fifteen ventilation fans over the years − primarily Nutone, Broan, and Fantech. Some of the units have integrated fan/grill assemblies and others have separate fan and grille assemblies. While the units with separate fans and grille are more expensive and more difficult to install, I have a preference for them because they are quieter when properly installed.

After looking at a large number of units, I have decided to the Fantech PB110 was the most appropriate unit for my bathroom. Figure 5 shows the unit.

Figure 4: Fantech PB110 Bathroom Fan.

Figure 5: Fantech PB110 Bathroom Fan.

The PB110 is specified to move 110 CFM of air with a static pressure of 0.25 inches of H2O. My air system will have somewhat more static pressure, so the air flow will be slightly lower. I will determine the actual air flow below.

Fan Flow Estimate

Figure 6 shows my ventilation systems flow rate for the static pressure that I am assuming. I started my analysis assuming a 90 CFM flow rate and my graphical analysis shows 92.5 CFM. This is close enough for this kind of HVAC work. I doubt I can read the chart in Appendix A to better than a 5 CFM precision.

Figure M: Fantech Graph Showing Air Flow For My Static Pressure.

Figure 6 : Fantech Graph Showing Air Flow For My Static Pressure.

Conclusion

I was able to design a ventilation system with a flow rate of ~90 CFM. I have built this system, but I do not have any tools that allow me to measure the exact fan flow rate. However, the fan air flow rate is clearly much higher than my old fan and it has eliminated the "steamy" bathroom problem that I have had.

I am very happy with my fan choice. It was a bit of a chore to install it because I had to mount the fan unit in my attic, which is heavily insulated and rather cold this time of year. However, the performance is superb and I finally have resolved my ventilation problem.

These calculations are similar to the calculations that I recently did on a dryer ventilation system. I will document those calculations in a post to follow.

Appendix A: Pressure Loss for Smooth Ducts

Figure 7 shows a chart of pressure loss per 100 feet of duct for various air flow rates (CFM) and duct diameters (Source). This chart may seem mysterious, but it simply a plot of the Darcy-Weisbach formula, which I work through here.

Figure M: Duct Pressure Loss Per 100 feet.

Figure 7: Pressure Loss in inches of Water Per 100 feet of Duct.

Appendix B: Straight Duct Equivalences of HVAC Items.

Figure 8 shows a list of common HVAC duct equivalences (Source).

Figure M: Table of Duct Length Equivalences.

Figure 8: Table of Duct Length Equivalences.

Posted in Construction | 4 Comments

PVC Expansion and How to Deal with it

Posted on 27-January-2015 by mathscinotes

"For want of a nail the shoe was lost,
for want of a shoe the horse was lost;
and for want of a horse the rider was lost;
being overtaken and slain by the enemy,
all for want of care about a horse-shoe nail."

— Benjamin Franklin

Introduction

Figure 1: PVC Pipe.

Figure 1: PVC Pipe.

I have written a post about the problems that I encounter with the improper use of PVC pipes and accessories in outdoor Fiber-To-The-Home (FTTH) deployments. During my normal reading about codes and regulations, I found an example of a bad installation and an example of how to properly deal with PVC expansion by installing an expansion joint. Both of these items deserve some coverage here.

Example of a Bad Installation

Figure 2 is from EC&M magazine and shows two problems:

  • Indoor-rated PVC pipe holding clips were used outdoors.
    Constant UV exposure weakened the clips and they dropped the pipe.
  • Temperature variation eventually caused the pipe to separate from its joint.
    I am not sure if this joint was glued, but I have seen pipes expand/contract so much that they break a glued joint. This joint might not have been glued and it just pulled apart.
Figure 1: Example of Bad PVC Installation.

Figure 2: Example of Bad PVC Installation.

Example of an Expansion Joint

The standard way to deal with this problem is to install an expansion joint. The video below shows an example of a good installation.

Conclusion

A little bit of extra time on this installation would have prevented a call-back.

Posted in Construction | Comments Off on PVC Expansion and How to Deal with it

Ship's Course Correction for Cross-Current Rule of Thumb

Posted on 22-January-2015 by mathscinotes

The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.

— William Arthur Ward

Introduction

Figure 1: Tall Ship Europa Under Full Sail.

Figure 1: Tall Ship Europa Under Full Sail.

I have lived most of my life in Minnesota, which is about as far away from the oceans as you can be in the United States. The idea of a planet mainly covered with  water has always fascinated me. I will never forget the first time I saw an  ocean (Pacific, Santa Monica, CA 1982). Fortunately, my work has provided me a bit of experience on ships and that experience was career changing − my early ocean experience involved laying fiber optic cable and that set the course of the rest of my career.

Today, I satisfy my nautical longings by reading about celestial navigation and the age of sail (e.g. Figure 1). I have been reading a book called "The Lo-Tech Navigator" by Tony Crowley and it contains a number of low-tech, navigation-related projects that I want to build. While reading the book, I ran into a rule of thumb that I thought I could derive here using a bit of vector algebra. The rule of thumb tells you the course correction (in degrees) required to compensate for the cross-current. I would state the rule-of-thumb as:

A 6° course correction in the direction from which the current flows is required per 10% of cross-current velocity relative to the ship's velocity.

To illustrate the rule, consider a ship sailing at 10 knots with a cross current of 1 knot, which means the cross-current velocity is 10% of the ship's velocity. The rule-of-thumb states the skipper must adjust his course by 6° in the direction from which the current flows to compensate for its influence.

My goal here is derive this rule of thumb. Let's dig in ...

Background

"The Lo-Tech Navigator" contains Table 1, which presents both the required and rule-of-thumb course correction for a small set of cross-currents. I want to duplicate this table.

Table 1: Cross-Current Course Corrections for a 10 Knot Vessel.
Cross-Current Rate (knots) Correction to Main Course (°) 6° Rule of Thumb
1 5.7° 6°
2 11.5° 12°
3 17.5° 18°
4 23.6° 24°
5 30° 30°
6 36.5° 36°

Analysis

Figure 2 shows the velocity triangle that represents the motion of a ship relative to the water and Earth.

Figure 2: Vector Model Of Ship Velocity in Cross-Current.

Figure 2: Vector Model Of Ship Velocity in Cross-Current.

Equation 1 shows the formula for the course correction, which assumes that the current is perpendicular to the desired direction of travel. Of course, this would rarely be true in practice, but the book goes into corrections to the rule-of-thumb to deal with currents that are not perpendicular to the desired direction of travel. I will not deal with these corrections in this post.

Eq. 1 \displaystyle \theta =\arcsin \left( {\frac{{{{v}_{{Cross-Current}}}}}{{{{v}_{{Ship}}}}}} \right)

where

  • vDesired is the velocity of the ship in the desired direction.
  • vCross-Current is the current velocity, which is assumed to be perpendicular to the ship's desired course.
  • vShip is the velocity of the ship relative to the water
  • θ is the angle deviation from the ship's desired direction required to compensate for the cross-current.

Figure 3 shows a screenshot of my Excel worksheet that tabulates Equation 1. The result is identical to the table in "The Lo-Tech Navigator".

Figure 3: Screenshot of My Excel Version of Cross-Current Correction.

Figure 3: Screenshot of My Excel Version of Cross-Current Correction.

Conclusion

The 6° correction per 10% of cross-current relative to ship's velocity is a useful rule-of-thumb. It also is a nice illustration of the use of vectors in what was an everyday application during the days of sail.

Posted in Naval History, Navigation | Comments Off on Ship's Course Correction for Cross-Current Rule of Thumb

Donor Chain Math

Posted on 20-January-2015 by mathscinotes

You have a good job now -- don't screw it up.

— Jesse Grant, father of Ulysses S. Grant. He had arranged a commission as a colonel for his son Ulysses in the Illinois Militia at the start of the Civil War. Ulysses had been having trouble getting a good job for years.

I just read an interesting article at Ars Technica on the mathematics behind setting up donor chains. The math is actually a variant of the prize-collecting traveling salesman problem, which is NP-hard.

The most common type of donor chain that I hear about is the domino donor chain (Figure 1) – there are other types of chains. The process begins when an altruistic individual steps forward to donate a kidney to a non-specific recipient.

Figure 1: Domino Donor Chain.

Figure 1: Domino Donor Chain.

Here is a recent story I saw on Youtube about a donor chain.

Posted in General Mathematics | Comments Off on Donor Chain Math

Mississippi River and Its Distance from the Center of the Earth

Posted on 18-January-2015 by mathscinotes

Engineers, like artists, often fall in love with their models.

— Tom Bement

Introduction

Figure 1: Lake Itasca, Minnesota is the Source of the Mississippi (Wikipedia).

Figure 1: Lake Itasca, Minnesota is the Source of
the Mississippi (Wikipedia).

In a recent post, I discussed how to compute the distance of mountaintops from the center of the Earth. This computation was interesting because we had to take into account the oblate shape of the Earth.

Figure 2: Tanker on the Mississippi in New Orleans.

Figure 2: Tanker on the Mississippi in New Orleans (Wikipedia).

This equatorial bulge is something that the Earth has in common with all other spinning planets. Jupiter, in particular, has a very pronounced bulge.

The fact that the Earth's equatorial diameter is slightly larger than its polar diameter can cause some interesting behavior. For example, centrifugal force at the equator causes the weight of objects at the equator to be slightly less than that of the same object at either pole.

Today, I saw the following problem in a book called "Thinking Like a Physicist" that illustrates that north-south flowing rivers can move further from the center of the Earth as they flow.

Explain (qualitatively and quantitatively) how the source of the Mississippi river can be about 5 km closer to the center of the Earth than is its mouth.

The tools I created to determine the distance of mountaintop from the center of the Earth can also compute the distance of Lake Itasca (Figure 1) and New Orleans (Figure 2) from the center of the Earth. Time to dig in ...

Background

All the background is included in this post, so just refer there for the details. There are many other web sources that discuss this problem. Here is a list of a few of these sources.

Analysis

All I needed to do was:

Here is the output from my Excel spreadsheet that does calculations.

Figure 3: Screenshot of Excel Worksheet for Computer Earth Center Distance.

Figure 3: Screenshot of Excel Worksheet for Computer Earth Center Distance.

I have confirmed the "about 5 km" statement from the book "Thinking Like A Physicist".  So we can state that the Mississippi river runs downhill with respect to sea level (aka geoid level)  but not with respect to  the center of the Earth.

You can also perform these calculations for yourself on this web page.

Conclusion

This was an interesting extension of my calculation efforts for the distance from mountaintops to the Earth's center. I rarely think about the role of the Earth's rotation on how our planet works. Yet, every night I look at the curved shapes of the weather fronts and I see the role of the Coriolis effect, which exists because of the Earth's rotation.

I live near the Mississippi River and writing about is fun. I plan on retiring in northern Minnesota, where the Mississippi River actually runs north for part of its course. It is a small, meandering river in this part of the country.

Posted in General Science | Comments Off on Mississippi River and Its Distance from the Center of the Earth

My Online Statistics Education Experience

Posted on 17-January-2015 by mathscinotes

Quote of the Day

I can't mate in captivity.

- Gloria Steinem on why she never married

http://www.guidemesingapore.com/blog-post/janus-news/janus-releases-singapore-business-formation-statistics-report-for-q3-2013

Figure 1: Statistics is Much More Than Charts and Graphs.

I have been fortunate in having worked for companies that have had enlightened education policies, which I have always taken advantage of. These policies allowed me to take training in very diverse areas, with one exception – statistics.

Over my entire career, I have always found myself lacking in statistical knowledge and I have found that training difficult to acquire without going on-campus, which is not an option for a person who travels as much as I do. My staff expresses the same frustration. For example, I was discussing some data analysis yesterday with one of our physicists and he commented that he wished he would have taken a Design of Experiments (DoE) course instead of Complex Analysis when he was at university. Nowadays, more and more people have found that using synthetic data generation can help fill some gaps when it comes to generating statistical data, but without that core understanding not much will change in the long term when it comes to the processing of such things. Having both would likely be the ideal for many individuals in this field.

I have done all that I could to remedy my personal situation:

This training has been useful, but I feel like I need a bit broader selection of courses.

Starting late last year, I have been taking classes from Statistics.com and this site may be the solution to my problem – they have an enormous range of classes. I am now taking my third class from this site and I have been very impressed with what I have been able to learn there. I have three more classes that I am planning to take there this year. My focus is on DoE – the limited DoE knowledge that I have acquired recently has changed how I work. I have also been learning about bootstrap and resampling methods.

Here is a summary of my experience with their courses:

  • Most courses are four-weeks long and very focused on applications.

    The four-week course length is both a strength and a weakness. The four-week structure means that Statistics.com has numerous courses and you can pick very specific topics to learn. The four-week structure and a desire to keep the prerequisites limited mean that the courses do not have much theory. I would like a bit more theory because it really aids your ability to apply your knowledge in new situations.

  • The instructors often are the authors of the textbooks that they are using.

    Again, a strength and a weakness. The strength is that the instructors have thought long and hard about how to present the material and they know their books well. The weakness is that some textbooks are just not very good.

  • The instructors have been very available and willing to help when you have questions.

    The student forums are the primary communication vehicle. The instructors give very timely feedback to your questions and I have never had a communication problem.

    Personally, I love using forums and I believe that they are a powerful way to communicate small bits of information. They are not so good for big pieces of information, like theoretical discussions.

Taking online classes can be a problem for many people because you must make an effort to reach out for help when you do not understand something. Reaching out for some is complicated by the fact that you must communicate your concerns through writing, which is difficult for many. Some students are embarrassed to have their "stupid" or "obvious" questions posted to a forum. My management experience has taught me to always ask "obvious" questions because I frequently receive answers that I do not expect. To successfully use online classes, you must be an active participant.

All my training for the last twenty years has been online and this has forced me to change my approach as a student. In my youth and early adulthood, I was the quiet guy in the back of the class who never said anything. I was so bad that I had one high-school teacher berate me in front of the whole class for my lack of participation – I believe he referred to me as "classroom ballast". If I had a boring class, I just blamed the teacher or the textbook or the subject matter.

My approach today is radically different – I have a responsibility to myself and the other students to actively participate. This not only makes the course more enjoyable for me, but it helps the other students and it motivates the instructor. I often receive comments from the other students on how much they learn from my questions. The instructors comment that they appreciate when I bring up real-world statistical issues that they can help solve.

My approach to participating in an online class is simple:

  • If a topic does not seem worthwhile, I ask how this topic is relevant.
  • If a topic is unclear, I seek clarification.
  • If I can see a connection or analogy with another topic, I mention that in the forum and ask for comment.
  • If I have an application for a technique, I write it up and show how I applied it (the instructors love this).

I will report on how my these classes go in a later blog. At this point, I am excited about the learning experience ahead.

Posted in Statistics | 3 Comments

Super-Strong Sawhorse

Posted on 16-January-2015 by mathscinotes

Quote of the Day

How far you go in life depends on your being tender with the young, compassionate with the aged, sympathetic with the striving, and tolerant with the weak… because in your life you will have been all of these.

— George Washington Carver

I have never really liked the standard sawhorse that I see many carpenters use. Here is an interesting sawhorse built using all compression joints that looks interesting to me. I will build a couple of these when the weather warms up. I have to do all my carpentry in my garage and it is pretty cold out there at this time.

Posted in Construction | Comments Off on Super-Strong Sawhorse

High-Speed Broadband, Fiber-To-The-Home, and President Obama

Posted on 15-January-2015 by mathscinotes

Quote of the Day

Even if all others do - not I.

— Father of Joachim Fest (German Historian), from the Gospel of Matthew, a quote he made his sons memorize during WW2.

I have been working for the past 15 years on making Fiber-To-The-Home (FTTH) real in the United States. Yesterday, President Obama visited one of our customers (Cedar Falls Utilities).  Here is a photo of the event. I have put a white oval around the Optical Network Terminal (ONT) that I have worked on. The ONT converts the optical signal to voice, video, and data service within the home.

ObamaHere is a closeup of that product and how it looks on the side of a home. Excuse the quality of the closeup photograph – it is just a snapshot from my phone.

ONT Installation

Here is a Youtube video with President Obama making the case for his high-speed broadband initiative.

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