tungwaiyip.info

home

about me

links

my software

Media

Yucatán Photos

St Lucia Photos

Photo Album

Videos

Blog

< February 2015
SuMoTuWeThFrSa
1 2 3 4 5 6 7
8 91011121314
15161718192021
22232425262728

past articles »

Click for San Francisco, California Forecast

San Francisco, USA

 

Algorithm for the Turnpike Reconstruction Problem

I have spend quite some time to come up with an algorithm to the solve Turnpike problem. turnpike algorithm in Julia. A causal look at says the complexity is beyond 2^n. But in practice it compute instanteously for a data set of about 16,000 delta numbers.

Here is the description of them problem. Suppose there is n increasing integers p_1 < p_2 , ... < p_n, we are given the difference of between every pair of points. The Turnpike reconstruction problem is to reconstruct the point set p_i from the distances of the form |x_i − x_j|.

2015.02.03 comments

 

Daddy is a TV Snatcher

The other day I have denied Tatchee TV time. I have been telling him to finish homework the first thing he return home. Instead he was fooling around, touching a bit of homework, having snack, reading comic books. Despite my constant nagging, he wasn't focus on his work. At the end it went pass the deadline I've imposed. So he lost his privilege to watch TV on that day.

TV Snatcher

He reacted strongly to this and basically just blew up. Somehow he felt he is entitled to TV. He haven't thought much about not finished homework on time as I've asked him to do. Perhaps in his mind the only think of I was being unfair to him.

Later that day he drew a picture himself that portrait me as a monster TV snatcher trashing TVs.

2015.01.12 comments

 

江湖大佬

Hang Hang Beard

2014.11.09 comments

 

 

Training for Xtracycle Edgerunner

I am excited with my brand new Xtracycle Edgerunner cargo bike. I tried it with the kids in a park last week. This week I start to carry some serious load on the street. The two boy weight 75 pounds combined. Keeping them balanced is a demanding challenge. So I have decided to do some training with myself first.

Edgerunner

I brought two 4 gallon water bottle from Sport Basement for $15 each. When filled with water, each bottle weights 33 pounds. Having both bottle filled will be a good training exercise for carrying the kids. This is day 1, so I only filled one bottle. I carried 4 gallon of water over the hill from Presidio and get home without incidents. Not bad.

Here are a few things I have learned.

  • This is a cargo bike. I have to accustom to the fact that it is just not as agile as a personal bike. In particular
  • It has a large turn radius, avoid incline it too much.
  • Any bumps on the the road is feel much more intensely with this bike. Go over even a small crack slowly.
  • Learn how to stop and start while keeping it balance. Try it on a hill.

One good thing is this bike has super low gear. It is perhaps a little faster than walking. As such I have little problem hauling 4 gallons of water over the hill! This gives me confidence to tackle the slopes around my house.

As of the bottles, after the training, they will be useful for car camping. Otherwise, they serve as water storage for earthquake preparation.

2014.10.18 comments

 

I Hate Ikea

Once upon a time, Ikea is my furniture palace. Their design is fresh and chic. Their price is low. The flat packaging is easy to carry home. But as I grow, I find their design does not cut it anymore. The construction is flimsy. The materials are cheap. And the design look fake. Their price is not even that low compare to other furniture with better quality.

One thing starts to irritate me is the assembly. I don't expect this to irritate me as I am always quite handy. I have built some simple furniture myself. Just putting a kit together should not be a problem. This time though I have find my match. This Svärta metal bed frame is legendary onerous to put together.

Look at this step below. Your goal is to fasten a metal strip to the horizontal bar of the frame. You have to use a 3 parts fastener. You put a rivet nut 100673 through a metal tube that seems to serve no function. On the other side you fasten it with a screw 112548. To make the screw to meet the nut is much harder that it looks. Not to mention you have to hold the long metal strip into place while you are doing that. I failed many many times, dropping the parts on the floor over and over again.

Bunk Bed Assembly

Finally I fixed both end of the strip to the frame. I move on to another similar strip. I found that I was missing a metal ring. After searching for a while, I have a suspicion where it might be. Shaking the bed frame confirms that a ring has unfortunately fell inside the frame's hollow tube during one of the failed attempt to screw them. Damn! How am I going to fish it out of the tube through the small hole! A lot of struggle and ingenuity was needed before I can pull fish thing out. And to add insult to injury, the same accident happened over and over again during the course of assembly.

This was not the only challenge. Several other tricky steps means I have to spend 2-3 hours in total to assemble it. Even blood has been shed for this thing. Some pre-drill holes turn out to be too small to fit the screw. Ultimately I have to drill a large hole to get the screw in. But before that, I tried to turn the screw with force. The attempt was futile. Unbeknownst to me the force has created some tiny metal shaving around the hole. The shaving is really sharp and I cut myself on it. After several days my finger still has not fully healed. By now I hope you can understand why I detest the Svärta bed frame.

Over the years I have assembled many flat packaged furniture. I understand it is more economic because it save on shipping and warehouse cost. I expect to do some work as a bargain. But putting together this kitchen cart gain me a new perspective.

kitchen cart rack

Here your goal is to assemble two racks. There are 10 slats on each rack, fixed to the two rail by 30 dowels and two screws. With some effort, you can stabilized all the lose parts and screw them together. This forms a rack. From what I can tell, a rack has a flat shape. What couldn't Ikea just package the rack assembled in one piece instead of excessive assembling of many small pieces? Flat is just not flat enough for Ikea. They insist on squeezing out every single inch of air they possibly can. In doing so they shows that their bottom line is more important than my time. When others do not respect my time it gets me angry.

2014.09.30 comments

 

Hang Hang's Mummy

Mummy

This is how Hang Hang wants his toy figures. Wrap them in bandages like mummies. I did that with paper stripes. Then he ask them to be placed in the boxes (coffins). This shows how it is done to his satisfaction.

2014.09.27 comments

 

California Beautiful

I was cleaning up my stuff. There is a large stash of maps I have collected. Everytime I went to a park, I picked up its brochure. Over the years, I have visited just about every major parks in the San Francisco Bay Area. There are wonderful mountain vistas, tranquil redwood forests, incredible coastlines in Point Reyes, gorgegous view of Golden Gate Bridge, the urban oasis Golden gate Park. Some of these places are within jogging or biking distance from me.

California Park Maps

Living in the San Francisco, it is easy to take them for granted. Now that I spread all the maps on the table and look at all the wonderful places around, I realized how lucky I am to be here.

2014.09.26 comments

 

教行行寫字

Learning writing

哥哥自己教行行寫字,寫得好有一個貼紙。 [more...]

2014.08.29 comments

 

New York Loves California

A Moveable Feast

I often heard how productive and how innovative California's agriculture producers are. Perhaps this is best illustrated in National Geographic's story on food import. The picture are fresh produce from four upscale markets in Manhattan. They traveled a long way from where they grown to the New York city. The origin with most varieties? California contributed 21 kinds of food out of the 60. This is more than 3 times the rest of United states. Actually California has produce more varieties than all other major region combined, with 6 from United States, 6 from Mexico, 5 from Italy and 3 from Costa Rica. [more...]

2014.08.04 comments

 

New York U-Lock

I'm shopping for a new bicycle U-lock. If a regular U-lock is not strong enough for you, there is a product line known as the Kryptonite New York U-Lock. These are extra heavy U-Lock made of hardened steel. Presumably people who need extra security would go for this. It also cost about double compare to a regular U-Lock. [more...]

2014.07.10 comments

 

Automation and Safety

The National Transportation Safety Board release a draft report on the Asiana Airlines plane crash last year, which result in 3 death. Commenting on role of the autopilot auto throttle system, they said, [more...]

2014.06.24 comments

 

我的六四回憶

六四已經過了二十五年了。一九八九年我十九歲,香港中大三年級生。回看昔日的激情,轉眼已經是一代人之前的事了。可悲的是傷痕還未痊癒,受害人的冤案還沒有平反。 [more...]

2014.06.04 comments

 

日出日落

日出日落,月缺月圓,一數原來已經活了16305天。[more...]

2014.05.26 comments

 

New Office

new office

We moved from a ghettoish office to a stylishly designed new office. Still need to get use to the surroundings. [more...]

2014.05.19 comments

 

Tatchee Photography

tatchee photography

Tatchee is using my camera to shot pictures. There are whole bunch of random pictures but also a few good ones. This big head shot of Hanghang is one I really like. [more...]

2014.05.18 comments

 

秘魯懷古徒步印加古道(2009)-下編

Arequipa

離開馬丘比丘,馬不停蹄乘夜車轉到Arequipa。這裡雖然是有百萬人口的秘魯第二大城市,但並不覺得擠迫繁囂。在舊城區內,美麗的歷史建築物圍繞著市中心廣場,市內的景點都可以從廣場步行到達。一會在廣場閒坐看遊人,一會到附近行人街購物喝咖啡,甚為寫意。在Arequipa見到的人是本地人為主,不像庫斯科滿是遊客,所以這城市亦更有實感。 [more...]

2014.05.16 [] - comments

 

 

Bye Bye Bay Bridge


Bay Bridge demolition

Bay Bridge demolition has started! [more...]

2014.05.07 comments

 

Bliss - the picture of dreamy green hill on every Windows XP

This is the familiar picture of a rolling green hill. Most of us have seen it because it is the default background image on Windows XP. It is such a dreamy picture that I always assume it is a computer generated image. [more...]

2014.04.17 comments

 

past articles »

 

BBC News

 

Nemtsov mourners to march in Moscow (01 Mar 2015)

 

Court ruling jeopardises Egypt poll (01 Mar 2015)

 

CCTV shows UK girls on way to Syria (01 Mar 2015)

 

Estonia votes amid Russia fears (01 Mar 2015)

 

US sex abuse suspect held in Brazil (01 Mar 2015)

 

Mass anti-immigration rally in Rome (28 Feb 2015)

 

US 'to deport Bosnian war suspects' (01 Mar 2015)

 

S Leone vice-president in quarantine (28 Feb 2015)

 

Chilean girl appeals to president (01 Mar 2015)

 

Emwazi 'felt like dead man walking' (01 Mar 2015)

more »

 

Slashdot News for nerds, stuff that matters

 

Uber Discloses Database Breach, Targets GitHub With Subpoena (2015-03-01T01:30:00Z)

 

Oracle Sues 5 Oregon Officials For 'Improper Influence' (2015-03-01T00:33:00Z)

 

As Big As Net Neutrality? FCC Kills State-Imposed Internet Monopolies (2015-02-28T23:28:00Z)

 

Under US Pressure, PayPal Stops Working With Mega (2015-02-28T22:34:00Z)

 

One Astronomer's Quest To Reinstate Pluto As a Planet (2015-02-28T21:32:00Z)

 

Blu-Ray Players Hackable Via Malicious Discs (2015-02-28T20:29:00Z)

 

Mysterious Siberian Crater Is Just One of Many (2015-02-28T19:31:00Z)

 

Ask Slashdot: Whiteboard Substitutes For Distributed Teams? (2015-02-28T18:25:00Z)

more »

 

TechPsychic Tech Rumors and Invented News

more »

 

SF Gate

 

Bay Area News (7 Jan 2012)

 

City Insider (11 Feb 2012)

 

Crime Scene (13 Feb 2012)

 

C.W Newius Column (10 Jan 2012)

 

C.W. Nevius Blog (11 Feb 2012)

 

Education News (10 Jan 2012)

 

KALW (11 Feb 2012)

 

Matier and Ross Blog (11 Feb 2012)

 

'Fro Patrol’ (28 Feb 2015)

 

Virtual reality, e-sports headline SF Game Developers Conference (28 Feb 2015)

 

Review: BlackBerry Classic a throwback, with limited capabilities (28 Feb 2015)

 

Farm-to-table marijuana startup throws posh Berkeley launch party (28 Feb 2015)

 

GameStop wins bidding for more than 160 RadioShack stores (28 Feb 2015)

 

Gas prices soar in California as supply shrinks (28 Feb 2015)

more »

 

Asia Times Online

 

Republicans in a blind alley on IS (Fri 27 Feb 2015 11:00:00 GMT)

 

The great Holy Land oil game (Fri 27 Feb 2015 11:00:00 GMT)

 

COMMENT The conceit of Western liberalism (Fri 27 Feb 2015 11:00:00 GMT)

 

BOOK REVIEW China's ambition not quite a 'plan' (Fri 27 Feb 2015 11:00:00 GMT)

 

SPEAKING FREELY Aung San and Dworkin: Well-lived lives (Fri 27 Feb 2015 11:00:00 GMT)

 

China's investment law reformed - but still grey (Fri 27 Feb 2015 11:00:00 GMT)

 

Building railways beats wars (Fri 27 Feb 2015 11:00:00 GMT)

more »

 


Site feed Updated: 2015-Mar-01 03:00