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Diary, July 2002

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    21  22  23  24  25  26  27
    28  29  30  31

Tuesday, July 2, 2002

Pattern 75: The Family

This patterns starts of with the sentense: "Until a few years ago, human society was based on the extended family." This is probably only true for highly developed countries. In the not so rich countries, the extended family is often still the cornerstone of society. Developed contries are characterized by a strong specialistation of jobs in combination with extensive education. Both work and education are no longer tied to the extended family. This also has led to individualisation of society.

Of course, the real question is whether you are better off in a society where you live in a close relationship with your extended family, but lack the freedom to develop yourself, or in a society where you can freely develop your potentials, but where you are not able to live in a close relationship with your extended family.

In the description a plea is made for forming voluntary "families" of ten or so. Then follows a quote from the final book of Aldous Huxley, which seems to suggest that we can better replace Christianity with Tantrik Buddism and that within the traditional marriage a sexually satisfying relationship is not possible. It also seems to imply that free sexual relationships and the loosening of the child-parent relationship are benefitial to society. Luckily, the author points out that there is still a need for a private room for each family.

Still, I wonder whether people in developed societies are willing to make all the sacrifices to start to live together as voluntary families again. Because labour is expensive in highly developed countries, houses are expensive as well. In the Netherlands there are all kinds of laws which forbid you to connect houses together as is suggested by this pattern.

Thursday, July 4, 2002

Object Constraint Language: a traditional formal language

Earlier this week, I read parts of OCL 2.0 Revised Submission, version 1.5, June 3, 2002 describing the Object Constraint Language designed for UML. (I did find an error in an example where the precedence of the operators and and implied was mistaken.) Section 2.1 Why OCL? of this document starts with the sentense: This exactly describes the problem with many diagram based specification methodes. The section continues to explain that OCL is introduced as a formal language that remains easy to read and write, and that in this respect it is not like a traditional formal language. The section states: However, if you continue reading the document, it appears that you have to write a complex expression using predicate logic to express a simple fact such as that in a set of books all ISBN numbers need to be unique.

Today, I discovered that I am not the only one making this observation, when I found the article Towards Executable UML by Scott W. Ambler. Appaeantly, the attempt to make OCL easy to understand has failed. Using keywords for mathematical symbols, does not make a language less mathematical. I am tempted to believe that there is something wrong with UML class diagrams, if you need a complicated language, such as OCL to repair some of its deficiencies.

Area of the intersection of three circles

Given the radius of three circles (ra, rb, and rc) and the distances between their centerpoints (lab, lbc, and lac) what is the surface of the intersection of these circles, given that it is larger than zero? (In a sense this is a continuation of the goat puzzle.) When we look at the form of the intersection of the three overlapping circles, we see that it consists of three circle segments. Each circle segment is part of one of the circles. If we draw a triangle between the three corner points (where the circle segments cross), the surface is divide into four parts. If we know the lengths of the sides of a triangle, its surface can be calculated with the following formulea:

(alternative formulea)

The area between a circle segment and a line connecting the two end points can be calculated based on the radrius (r) and the angle (delta) with the following formulea: If alphaX stand of the angle of the circle segment of circle X, and kX the length of the side of the triangle between the circle segment of the circle X, then the area of the intersection is expressed by: We only need to determine the values for unknown parameters. Now kX can be calculated from alphaX with the following formulea: That means we only have to determine how alphaX should be calculated. Lets see how alphaa can be calculated. For this we look to the triangles that can be formed by the three center points of the circle (Ca, Cb, and Cc) and the two end points of the segment of circle with radius a, which we will call Pab and Pac after the circle whoes segment the touch. From some of these triangles we know the lenght of all tree sides. That means that we can calculate all the angles using the following formulea. In this d and e are the lenghts of the sides of which the angle needs to be calculated, and f is the length of the opposing side. The angle of the triangle (Ca, Pab, Pac) is equal to the angle of the triangle (Ca, Pab, Cb) plus the the angle of the triangle (Ca, Pac, Cc) minus the angle of the triangle (Ca, Cb, Cc). That means that for alphaa the following expression is true: Now presume that the radius of all circles is r and the distance between them equal to l, then, if I got it all right, the area must be equal to: The exercise of simplifying this even further is left to the reader. (Hint: rewrite sin(a - b).)

Friday, July 5, 2002

Pattern 21: Four-story limits

The introduction to this pattern mentions that spending a lot of time in an height appartment increases the chance for psychological problems. It suggests that this is caused by a lack of social interactions. It does not mention the possibility that people simply feel less comfortable when being high above ground level. If it is only the lack of social interactions, then the problem does not simply lie in the height of the building. That means that there could also solutions to the problem. I could think of a Roof Garden pattern or a pattern to mix housing layers with common facilities. Also pyramid shaped buildings could over come some of these limitations.

They write the right stuff

A story about how to write bug free software.

Saturday, July 6, 2002

De Waarbeek

Today, we went to "De Waarbeek" again, just like last year. Annabel had brought some bread to feed the ducks. When we went out rowing, there was only one duck, but luckily there were also some fish who liked the bread too. It was not a very sunny day, and at one point it started to rain. We found shelter in the little trains station. We decided to feed Andy there. Suddenly, he started to vommit. First only the "milk" we had just given him, but then also the food from a few hours ago. We spend some time cleaning him, and then decided it was time to go home. We left about half an hour later, when the sun was out again.

(next visit)

Sunday, July 7, 2002

Annabel being kidnapped

This morning, my mother came to take Annabel with her. On invitation from a sister of my mother and her husband they are going to stay in the Atlantic Hotel until coming Wednesday. But then my mother told us, that afterwards, Annabel was going to stay with her for another two weeks, and then would stay with my sister for about a week, and that we would only see her again on July 29. We could do nothing else then agree. Li-Xia ran upstairs to collect some more clothes. We already had agreed to stay with my mother during the last week of this month, so Annabel is going be away from home for almost four weeks. She did not complain.

Watching pictures

This afternoon, Andy and I looked through is photo albums. I was surpriced by his attention span, and that he kept his patience for a long time. He was really interested in watching the pictures. In this sense his behaviour is more of a five year old than a two year old. Also the rest of the afternoon, he behaved very nicely. Is it because Annabel has gone away?

I spend some time scanning some of his pictures, because we received the request to send in some pictures of his face such that they can be studied by some experts who are interested in the chances of the cranofacial anomalities with the Kabuki Syndrome. (A page with all the pictures.)

Tuesday, July 9, 2002

Pattern 20: Mini-buses

I find this a very interesting pattern. There is a PostScript file available of the first article mentioned in the pattern. One wonders if the concept is really so good, why it has not been implemented more often in the past 20 years. I do not know of any implementation here in Holland. The description neglects the fact that physical handicapped people often need specialize transportation which needs to be door-to-door, thus cannot make use of the mini-buses system.

Pattern 223: Deep Reveals

An good pattern. Can even be applied to existing houses. In the picture on the front page of this pattern, it looks like window doors are used. The combination of these would make a nice pattern as well. Actually, it looks like this pattern has been applied a lot in the past. Why did it get lost?

Pattern 224: Low Doorway

Although, I understand the effect produced by this pattern, I doubt whether it should be included as a pattern, because it cannot be applied very generally. We as the Dutch are among the tallest people in the world, and it would be real problem if this pattern is being applied too often.

Wednesday, July 10, 2002

Power failue

We had a power failure this morning. It started at 8:25 and lasted till 12:45. Just before it ended there was a short flash. Later, I heard that at another place at the campus power had returned at 12:30 and that there was a short dip around the time we saw the short flash.


Pattern 171: Tree places

I do like trees, but it goes a little to far for me that they, along with people and houses, constitute one of three basic parts of my environment, as is suggested in the text of this pattern. The text seems to suggest that trees in forests do not need care to survive. Actually, many trees in forests do not survive, but die before they mature. A natural forest is often a mess. I also do not believe that if trees are in places where people socialize, that they are being taken care for. Taking care of a tree often requires specialized knowledge and tools (especially when they get tall). Another problem with trees as architectural elements, is that they usually grow very slowly, which means that it can take decades before they perform the function that they were planted for. And once they are tall, it is sometimes a problem to keep them in a managable size.

Saturday, July 13, 2002

The new cabinet

The formation of the new cabinet is in its last stage: selecting the ministers for the different departments. There is a coalition of the Christian Democrats, the LPF (Lijst Pim Fortuyn), and the Liberal party. The LPF did not get five departments as they had expressed in May, they only got four. Also the Liberal party got four departments. The Christian Democrats got six departments, and Jan Pieter Balkenende will be the new prime minister. If today elections would be held, the LPF would drop from 26 to 18 places in the parlement, the Liberal party would go from 22 to 24, and the Christian democrats would go up from 43 to 47, making them by far the largest party, even larger than number two and three together.


Monday, July 15, 2002

Difficult optimization problem

In software package I am developing there is a lane-view of processes available. In this lane view the processes are placed in lanes depending on a certain criteria, such as for example, which kind of users are involved in each process. It is possible that a process needs to be placed in more than one lane. In that case, the different parts will be connected. Also the processes are connected with all kinds of errors that can cross lane boundaries. The order of the lanes can be chosen by the user. Not each order gives a nice lane view. I was thinking about a simple algorithm for ordering the lanes, such that the various kinds of lines between the lanes would be a short as possible. But I could not come up with a simple algorithm.

In mathematical terms the problem can be stated as follows. Given:

	Lanes : Set(string)
	Value : Function(PowerSet(Lanes) -> num)
	Order : Bijection(Lanes, range(1,count(Lanes)))
Such that:
	For v in PowerSet(Lanes) with count(v) > 1
	Sum Value(v) * ((For l in v Max Order(l)) - (For l in v Min Order(l)))
is minimal.

Tuesday, July 16, 2002

Star Wars: Episode II

Yesterday evening, I went to see Star Wars: Episode II in a local theater. (I saw the trailer of this movie on December 27, last year, the last time I went to see a movie.) I found the movie rather impressive, better than the last one, which I watched some months ago on TV. I watched till the end of the credits, when everybody else already had gone. When the sections about the computer related special effects came, four columns were used to put down the names. The software I work on, is most of the case much less visible (and visual) as there are doing in the movie industry.

I do feel, that there are some illogical things in the story. One of the most critical moments is the fight of Yoda with count Doucku(??). I do not understand why Yoda uses all his strenght to hold the pillar in the air, while it would have been much easier to either pull or push Anakin and Ben away.

I find it a strong point that apparently evil can develop itself without being noticed for a long time, right under the nose of the those fighting for good, and that the leader chosen to lead the army to save, will actually turn into the evil ruler. In a sense it is amazing to see how peace slips through the fingers of those who want to maintain it.


Pattern 128: Indoor sunlight

Reading this pattern, I immediately had to think about that special feeling I always got when the sun was shining on my back while washing my face when I was still living in Woerden with my parents. Not in all climates the sun shines a lot. We here in the Netherlands are rather familiar with grey skies, which make all colours look pale. That kind of weather causes all sides of the house to be almost equally lighted. Building a sun room with a trasparent roof on the North side can have a cause almost the same effect as windows on the South.

Curly kail

Last Saturday, while looking around in some super market, I noticed some frozen curly kail. We decided to buy to packages with a total weight of 500 gram. At home, I peeled two and a half kilo of potatoes to make a pan full of curly kail hotchpotch. Of course, we could not finish it in one go. But because there were some other left overs that Li-Xia liked better, I ended up eating it for another three nights. Today, I finally managed to finish it. I think I will wait until the first fresh curly kail becomes available again.

Wednesday, July 17, 2002

Pattern 130: Entrance room

For looking who is standing outside also a spy hole can be used, and may be prefered above a window in certain curcumstances. A light outside might also be needed in the evening. The pattern does not distinguish between a back door (used by members of the family) and a front door (used by non-family memebers). Some of the function prescribed to the "entrance room" are typically those you would find at a back door. In the Netherlands most houses have an entrance hall that separates the front door from the living room. In certain old parts of the cities, where it is not possible to reach the back door from the street, you can indeed find bikes and such to be placed in this enterance room.

Pattern 156: Settled work

This pattern sounds very interesting to me, the idea of finding a job at old age that seemingly integrates with the rest of your life. But the pattern does not present any clear examples, so it is not completely clear what kind of work is meant. I find it hard to image how this could work out for me as software engineer. I also do not find this much of an architectural pattern. It is more of a life-style pattern.

Thursday, July 18, 2002

SGP (Cont'd)

Today, I read that the Clara Wichmann institute want a trial court case about whether a political party is allowed to exclude woman from becoming active members of the party. They are looking for a woman who wants to act as the trial case.


Today, our boss informed us that last Saturday he jumped from a height of 112 meters (more than 300 feet). Luckily, his feets were attached to a string of rubber.

Giving a performance for Andy

This evening, when we had to feed Andy, we decided to play with "De Tuttels" dolls, while watching a video about them. This was the first time we were able to feed Andy some pureed fruit, without having to hold his hands tied.

Friday, July 19, 2002


MFC stands for Microsoft Foundation Classes, a framework used in many Windows application (except those made by Microsoft, such as MS Word). Today, I found two pages explaining why MFC is bad: MCF Beef and Why MFC Sucks.

I also found a beautiful page about small application. Small in the sense of byte size, not in the sense of not having a lot of functionality. Many of these applications do not make use of MFC. The rest of the evening, I played with the Sound Frequency Analyzer and Xaos.

Sunday, July 21, 2002


Annabel, who is staying with my mother phoned me early this evening to tell me how she is doing. She told me that she had seen a rainbow earlier today. She has been staying with my mother for two weeks now, and is having a good time playing with all the children in the street. She also went with my mother to the tennis court and learned to pick-up the balls. All the old people love her very much. She sounded very happy through the phone.

It had been raining with us almost the whole day. But around half past eight I saw some sunshine, and when I noticed that it was still raining, I hope to see a rainbow. And there was indeed one. I managed to take some pictures of it.

Wednesday, July 24, 2002

2002 NT7

This is an astroid that is maybe going to hit the earth in 2019, it said on the news. Or at least that is what the BBC reported. When I looked up the information, I discovered that the chance is only about 1 out of 163934 based on the observations made so far. That is much smaller than the chance that I will have died by that time as result of some disease.

If it would hit the earth, it would do so at a speed of 28 Km/s, that is 100800 Km/h, a hundred times faster than a passenger plane. On inpact it will produce an explosion equivalent to 1200000000000000 Kg of dynamite (TNT). The big question is, what should we do, if it turns out it will indeed hit the earth. The astroid only weights 1200000000 Kg. Could we just slightly change its orbit, such that it would not hit the earth, or should we just evacuate that part of the earth that is going to be hit. In any case, we will still have at least 16 years to answer that question.

I already played with the idea of writing a science fiction novel about this scenario with earlier astroid warnings. An astroid impact already has been subject of many books and movies, all being very unrealistic about the true facts, I am afraid. The real question is, could we as human-kind avoid such a big threat. Would it make an end to all wars, now we do have a common enemy? Or will it end in a brutal fight for the fittest? If the chance would go up to 1 out of 5, I bet that the first thing will be an economical crisis, probably triggered by a stock market crash.

Thursday, July 25, 2002


This morning, we were with Andy in the hospital for a regular check. He had dropped to the ground near the paediatricians office as he often does when he has been walking some distance. Then we asked him to come, and he managed to stand-up all by himself without holding onto something. This is the first time we saw him doing this.

Tuesday, July 30, 2002

A day in Utrecht

We are staying with my mother for a few days. Today, I went to Utrecht, which is only a short distance by train from Maarn, a small village about 15 Km from where my mother lives. I arrived in Utrecht a little after nine. Most shops were still closed. The bookshop Broese was open. It is the biggest bookshop in town. I spend the whole morning in their computer science department and looked at many books.

Ways to read a book

I found one book that had a graph in the beginning explaining the dependencies between the various chapters (about twenty). This immediately made me think about the number of ways the book can be read. Actually, this is not so difficult. You simply have to build another graph, in which each directed vertex represents a certain state of the chapters you have read, and in which there are edges between vertices representing the additional reading of a chapter. The number of ways to read the book is the number of directed paths between the vertex representing none of the chapters being read and the vertex representing all chapters being read.

The Art of Computer Programming

I was a little disappointed about Kunth's multi-volume master work The Art of Computer Programming, because it contains a lot of low-level algorithms, which seems irrelevant for current day computer programming. I do not expect to see fragments of machine code in current day computer science books. Although the three revised volumes contain a wealth of information on various algorithms, it seems Knuth has failed to write a timeless book. Maybe it is because he took low-level principles as a starting point. I believe he would have been more successfull if he would have taken high-level (mathematical) principles as a starting point. (This is an approach I have been trying to explore.)

Agile Software Development Ecosystems

After three hours of looking at many boring books, the only book I found worth buying was Agile Software Development Ecosystems by Jim Highsmith. I did have a look at many of the more "hard-core" computer science books, such as the C# and .Net books, but I couldn't find any that was interesting enough. I did consider buying Free as in Freedom about Richard Stallman, but in the end I found the hard-cover version a little too expensive, also because the contents of the book is made available on-line.

De Slegte

Of course, I could not stop walking through the bookshop "De Slegte", as I always do when I have the chance. I have been playing with the idea of making a virtual reality model of the shop (using Flash), and thought about taking some pictures from the interior. But it is forbidden to take pictures inside shops, and the shop was full with surveliance camera's. I did take one picture of the canal from the cellar of the shop, but that does not show anything of the shop.

Wednesday, July 31, 2002

Visting family

Today, Li-Xia, my cousin Frans, and I, visited some far relatives of us. (Our closest common ancestor is Johannes born in 1802.) We looked at some of the places where our ancestors and relatives lived. We also exchanged some information about our family histories.

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