WordPress plugin install failed

Posted on January 10, 2011 by Justin

These days WordPress is installing and updating plugins via ftp which is very convenient once things are set up properly, but it can be a hassle to work out the kinks. For example, I kept getting errors from WordPress when installing plugins and themes–”Could not copy file” and/or “Could not create directory.” Oddly, changing the ownership of my website files and directories to the user used by Apache2 solved the problem.

sudo chown -R www-data:www-data /srv/www/justinratner.com/public_html

In my situation, apache2 was being executed by a user www-data in a user group www-data. To determine what user apache is running under, simply use ps aux | grep apache. The -R in the above command will apply ownership to all of the files and directories within the specified directory as well.

After running this one command, everything worked great!

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Get Advice, Get Success

Posted on February 18, 2010 by Justin

I don’t talk about my startup much on this blog, and that is because I don’t feel that I’m enough of an authority on the subject of startups to preach about the way things should be done. However, I have learned something very valuable in my meetings with very successful people that I want to share. The following is my recommendation on how to seek advice.

When you approach someone that has been very successful, the temptation is to ask copy-cat questions like, “How should I obtain customers?”, “What should be the role of a CEO in a startup?”, “How do I get investment capital?”. These questions and those like them need to be abandoned. Instead, you should strive to understand your advisor’s situation. What is their background? What was the business of the company that they were so successful in? What kinds of people did they have around them? This is because most successful people, when asked questions like those at the beginning of this paragraph, will simply tell you that you should do things the way that they did them–less directly of course. However, as the advisee, it is important to understand that every situation is different. You must understand what has worked for people in a variety of situations and draw parallels between their situations and yours.

The key is to build a model for success within your mind, and this can only be done by analyzing many successful people in many different situations. There are people out there who say luck plays a huge part in the success of a startup. That may be true to a certain extent, but I have heard too many stories of entrepreneurs who have failed due to mistakes that could have been avoided with the assistance of a better model for success.

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How-to avoid static shocks

Posted on January 7, 2010 by Justin

In every introductory physics course, there is always that same old demonstration where  the professor rubs a plastic rod with some sort of fur and causes small bits of paper to jump off the table  or a small, suspended ball to swing towards the rod. Students are introduced to the wonder of static electricity. However, it is not wonderful at all. It is actually fairly troublesome. Static electricity can fry electronics, and people often find themselves shuffling around their homes in the winter and getting zapped by every household appliance. Surely, this is no way to live!

The first thing to do is throw on your fancy leather moccasins.  If you lack Native American heritage, any leather-soled shoe will do. What’s that? You are fresh out of leather-soled shoes? That is o.k. I don’t have any either. Those of us without leather-soled shoes must be very careful to remember something very important before we go operating that toaster or touching that door nob. The secret is to find something that is a large, o.k. conductor rather than an excellent conductor like most metals. Hold your hand against this object for 3-5 seconds before touching that toaster. The latex paint-coated, metal door frames at my house seem to work best for me. The latex paint provides enough resistance to slow down the dissipation to the metal door frame. I understand that not everyone has painted, metal door frames in their home. You may have to experiment to find what works best.

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Installing Ubuntu Karmic on eeePC 1005HA

Posted on January 5, 2010 by Justin

Today, while installing Ubuntu 9.10 Karmic on my 1005HA eeePC that came preloaded with Windows XP, I ran into a few “gotchas.” First, I tried to follow the widely available instructions for installing Ubuntu from a bootable USB (i.e. here.) This did not work for me because my netbook rebooted into windows when I selected install ubuntu. I tried a few changes to various BIOS settings, but nothing seemed to work.

After a while, I found out about Wubi. I put the wubi.exe in a folder on my Windows desktop along with an ISO of the latest Ubuntu Netbook Remix, and, simply, followed the installation process. Unfortunately, the 1005HA eeePC comes partitioned into a C: drive and a D: drive. I found out that installing Ubuntu on the D: drive will result in a problem when booting Ubuntu. Ubuntu will try to load the kernel, fail, and go to the GRUB prompt. I was able to correct this problem by installing on the C: partition instead.

One more thing, when loading Ubuntu for the first time, the eeePC will fail to connect to any wireless networks. Instead, a wired connection must be established and the update manager must be run. After Ubuntu is updated, wireless networking should work perfectly.

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Depression: Unfortunately Named

Posted on December 8, 2009 by Justin

It is perhaps among the greatest follies of popular culture that the great plethora of clinical depression disorders walking around out there are lumped into an over-encumbered, nondescript word like depression. People with clinical depression are constantly enticed with phrases like, “What’s the big deal? Everyone’s depressed these days.” Inevitably, this leads to shame, guilt and a failure to pursue treatment in the people that this disease troubles. It is important for people to realize that a sad brain is physically different from a clinically depressed brain: nice resource from Dartmouth.

Of course, it is true that there are a whole host of diseases out there that are accompanied by a plentiful basket of stigmas, but with most of these diseases, it’s much easier to find out whether you have them or not, get treatment and move on with your life. Clinical depression is a different animal because certain types may impair a person’s concentration, judgement and motivation. A disease that effects motivation in conjunction with a society that is intolerant towards the admission of having it is a fatal combination.

Sadness is not depression. If you suspect that you or someone you know has depression, it is important that treatment is found. There is no shame in seeking a happier, more fulfilling life. Depression is a solid barrier that must be traversed with help before other, every-day obstacles in life can be taken on.

Free and low-cost treatment options: http://depression.about.com/cs/findadoc/a/freelowcosttx.htm

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Antenna Gain vs. Amplifier Gain

Posted on November 13, 2009 by Justin

It has come to my attention that sometimes even electrical engineers who have been in business for decades have a hard time distinguishing between two very different forms of gain.The difference is very simple. Anyone should be able to understand it.

Amplifiers increase the power in a circuit. To do this, they require a source (i.e. a power supply).  Amplifier gain is equal to the power out divided by the power in. How does your thuggin’ next door neighbor generate those loud, obnoxious beats? He does this via heavy-duty amplifiers that suck power from his engine into his audio system. This shows you that rap music is bad for the environment. Anyway, I digress.

Antennas do not increase power. There is no source in the antenna creating gain like there is in the amplifier (well, unless, the antenna has an amplifier). An omni-directional antenna of a particular efficiency radiates the same amount of power as a directional antenna of the same efficiency. The difference in gain comes from the way the power spreads out in space. Very directional antennas are high gain while omni-directional antennas are low gain. Antenna gain is a measure of how the antenna concentrates energy in a particular direction.

Here are some antenna radiation patterns to look at. By the way, antenna gain also indicates how well the antenna can receive energy from a particular direction.

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Atlanta Technology Angels (ATA) “Open House”

Posted on August 19, 2009 by Justin

Knox Massey and ATA hosted an “Open House” for Georgia technology companies today. I was able to sit in on my brother’s prensentation to them about his venture that he is seeking seed-stage capital for: Knackity.com. The presentation lasted about ten minutes, and there was a good five minutes of Q&A afterward.

The event left me wondering how many 18 year olds are brave enough to stand up infront of a group of seasoned investors and pitch their ideas. Even better: how extraordinary is it to not be laughed out of a conference room by said investors as an 18 year old? Instead, the group sitting in on the presentation listened carefully and asked exactly the questions we expected: what differentiates you from company X? How will you attain users off the bat? What about your other commitments (school)? My brother showed that he has given thought to all of these questions already, and I think his audience respected him for it.

For a first-timer, I say job well done.

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Thoughts on Shotput Ventures Demo Day 2009

Posted on August 10, 2009 by Justin

Today, I attended the first “Demo Day” event that I have ever been to. For those unfamiliar with the term, a “Demo Day,” in this context, is a day in which start-ups demonstrate their products after working through a program like that offered by Shotput Ventures. Shotput’s program is essentially a start-up accelerator (3-month program) for capital-light web companies.

The companies that presented:

There was a very obvious trend amongst these companies that may be attributed to the advisement they received while participating in the Shotput Ventures program: existing Web 2.0 integration. All of these companies sought to integrate existing Web 2.0 platforms (i.e. twitter, facebook, blogging portals, etc.) rather than constructing their own. The audience saw a twitter feed here, a blog list there, and share button to boot. This certainly makes a lot of sense from a development point of view. Why waste time re-inventing the wheel when you can simply use the API’s of already-available and widely-used technologies? However, this may just be a higher-order motive.

Internet users are becoming more accepting of Web 2.0 everyday and start-ups know this. In a few years, a typical web-user may not even accept a web application that is not integrated with Web 2.0 in some way. Sure, the pattern that emerged at “Demo Day” today may have simply been due to Shotput’s advisement. However, it is the rapidly changing landscape that is motivating advisers.

Twitter feeds are only the beginning. There is a larger paradigm shift at play. Consumers are more interested in product information from their fellow consumers than superficial content on retail websites. Tech developers are more interested in blog articles written by fellow developers in the trenches than books written by academics. People want information produced for them and by them. It is only natural.

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One of a kind and worth it…

Posted on August 4, 2009 by Justin

A friend of mine and I were cruising down the highway on the way home (Atlanta) from Denver, CO discussing anything and everything of interest when we came upon the topic of pricing. Wow, talk about an underestimated problem! How do you price your products or services? You might start by gathering on comparable products and services offered by your so-called “competitors” or by analyzing your costs and adding a little sugar on top. However, are these really effective strategies that will maximize your profit? A simple Google search will reveal millions of websites and articles all about pricing. Some of them will tell you it’s all about the number “9″.  Others will tell you to take the price that first comes to mind and multiply it by 10.

Here’s my simple 5-step solution:

  1. Read what other people have to say about pricing and take it with a grain of salt.
  2. Turn your brain on.
  3. Limit assumptions about your market. (i.e. All basketball consumers are looking for the cheapest basketballs that they can get their hands on.)
  4. Actively test price points to maximize your profit.*
  5. Enjoy the fruit of your free-thinking nature.

*Caution: past price points can have an effect on how customers perceive the new price. This is especially true for goods or services that have to be revisisted and purchased again. It would not necessarily be a good idea to price a steak at your restaurant at $10 and, later, test a price point at $100 to see what will happen.

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Am I seeing double or is it birefringence?

Posted on July 17, 2009 by Justin

Here is a neat example of a physical phenomenon known as birefringence. Many materials exhibit birefringence. For an example of how this property appears to the eye, see the image below.

Materials that exhibit birefringence are anisotropic. This means that they bend light at different angles depending on how the incident light is polarized. Since most light that we come into contact with on a daily basis is a combination of different polarizations, we see multiple images when we look through an anisotropic material like calcite.

More information on optics and birefringence:

http://en.wikipedia.org/wiki/Birefringence

http://www.physics.gatech.edu/frog (see the optics lectures)

http://hyperphysics.phy-astr.gsu.edu/hbase/HFrame.html

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