Sensors Assignment Observations – A2b

Most of you did quite well on the second portion of this database assignment although there was some confusion about what I meant by “comments”.  Here are some observations.

Comments Desired

I asked for comments in two criteria of the grading form.  I was asking you to think about the sensors.  Here are the criteria and what I was looking for.  The comments could be in comment fields, but it was certainly easier to put them in a separate document as many of you did.

• Building Systems asked for “comments on the similarities and differences”  For this I expected you to identify similarities and differences between the sensors for different building systems.  These might include comments on:  size, frequency, cost, life span, sensitivity…..
• Characteristics asked for “comments and tolerances”.  I was hoping for comments on the characteristics of the sensors including your own observations such as whether these made sense to you.  I gave liberal credit here for “tolerance” info and manufacturer’s info, but was hoping for more.
• Overall asked for “Exceptional work with great thought”.  To get full credit here you needed to explain your thought process and any conclusions you reached about the assignment as a whole.

MS Access Comments

So long as you had a working database you got almost all credit.  To get credit for “Explores capabilities of database including reporting and formatting” you had to demonstrate going beyond what I created in the demo videos.

I offer the following observations about using Access itself:

• A number of you created relationship links that would cause difficulties in practice.  That’s not suprising when getting started and I didn’t deduct for it.
• The “measurements” table in my video is an example of a ‘trick’ often used in DB design.  If you have (in our world) a bunch of physical things that you want to use together it’s often best to create a new table (measurements in my case) that is an abstract thing that relates to the physical things you’re interested in.
• In real situations you may often want to use one table in multiple relationships.  Access handles that best by creating multiple “instances” of that table.  If you’re interested I can explain it further.
• A nice technique for documenting a table (or writing general comments) is to create a “Documentation” table that isn’t linked to others and has fields for writing comments.

Jim Mitchell

MS Access Assignment - A2a

Most of you completed this assignment with few or no problems so there should be  a great deal to say.  However:

Next Assignment

• A reminder that for A2b I expecting you to use real sensors that you’ll research using catalogues or other sources.  It’s OK if not every field has data – that will show how hard it can be to truly characterize a sensor from the published information.

This Assignment

• Some of you deleted a record in a table and then added it back, expecting to be able to assign the old ID number.  That doesn’t work:  When Access says “unique” it means unique for all time for a given table.  It actually is a “feature not a bug.”  If you were able to create an ID that had already been used you might inadvertently link to records you hadn’t intended in other tables.  It does show that you want to be careful deleting records – the general rule is: Don’t.  Most database designers hide the ID and key from users to avoid this confusion.
• Some of you wondered why have forms rather than just enter info into queries or tables.  The answer is that you can make forms very “pretty” and can also associate “logic” with them to do interesting things.
• A few of you struck out on your own rather than following the videos exactly.  Congratulations!  Unfortunately that exposed you to the more complex side of Access such as multiple versions of a table being linked – that can be very helpful, but it’s quite confusing.
• Finally, only one person reported playing with the templates.  I recommend it.  Some of them are extremely well developed.  You may find them hard to understand initially since they use lots of features we haven’t touched, but they do neat things and can be modified to suit your needs much more rapidly than starting from scratch.

Jim Mitchell

Paper Drafts – Some Overall Comments

I’ve just completed reviewing all the paper drafts and returning them with comments.  Most of you selected interesting topics and pursued them well – the overall quality was good.  There are, however, some issues that are worth addressing

• A few of you were under the required length – not many.  Be sure not to try and “pad” the length with extensive quotes.  They don’t count.
• A few of you attempted ambitious projects involving programming Revit or something similar.   In those cases I suggested deciding on fall-back strategies of how to complete the paper if the project couldn’t be carried to completion.
• As always, citing literature sources is important at the point you use it, not just at the end of the paper.  I fed several documents through the TurnItIn process to check that there weren’t problems and indeed found one (fairly minor).  I will do so again with the final draft.
• Creating subdivisions (sub-headings) of the paper can be very helpful both to the reader and the author.  They usually mark a major change of thought.
• In several cases there did not seem to be an overall objective for the paper, a “question” or “thesis” that was being addressed.  Just providing a summary of other people’s work isn’t enough.
• Please note that I did my best to be lenient and evaluate where you were “going” with the paper rather than look at it as a finished document.  I will be significantly tougher when looking at the final draft, applying the grading criteria firmly.

Jim Mitchell

New Services with BIM

One of the discussions this week asked your ideas about possible new services that could be offered using BIM.  Many of you chose to talk about improvements in existing services rather than possible new services – things for which someone would pay extra.

That inspired me to come up with my own list.  I offer the following link as a discussion point.  It is not exhaustive and certainly a number of my suggestions are debatable as to practicality and/or who would either offer or buy them.  Nonetheless I suggest that there are many possibilities.

New Services Possible Using BIM capabilities through the building life cycle

If any of you would like to add to this list or modify it just contact me and I’ll give you editing privileges.

Jim Mitchell

Week-6 Discussion – BIM Wrapup

This week’s posts, the majority of which I highly recommend to you, are an excellent wrap-up for our study of BIM in the first half of this course. Most of you agree that it is going to have a major effect on the construction world with specific changes including:

• Further globalization of design & fabrication of building components - as in the aircraft and auto industries
• Restructuring of the design and construction process and the relationships between the players in that process
• Increased demand for skilled professionals - you
• Decreased demand for unskilled professionals - with unemployment consequences
• Ever increasing demands on hardware, software & internet communication
• Opportunities for new services
  • I was surprised that none of you considered the possibility of designers and contractors extending their services through the life of the building by use of the BIM tool. I can see many opportunities there.

Some of you recognized that not every technical improvement (BIM in this case) comes to pass or is as splendid as the enthusiasts forecast. Concerns you expressed included:

• BIM adoption is slower than Eastman et. al. claims
• Humans operate these systems and still make mistakes or are dishonest
• The technical challenges of interoperability, file size, etc. are major are significant
• The book doesn't address legal and liability issues - ones that are often extremely important
• The consequences of changes in the system may produce socioeconomic effects that we regret - unemployment being the most obvious one

Jim Mitchell

Missed Lecture 2/10/2010 - Videos

Thanks to our second snowstorm of the past few days you’re all enjoying a day without Drexel.  In order to make up for the missed classtime I’ve made a series of eight videos that contain most of the material I intended to cover today.  They’re in the same “playlist” as the MS Access Demo that was announced in the previous blog entry.

Today’s Videos are:

Number	Title	Length
1	Intro	10:17
2	BIM Wrapup	8:45
3	Data Overview	7:43
4	Database Example - Amazon	8:25
5	Databases – Why we use them	13:22
6	DBMS & Terminology	8:25
7	Relational Database Concepts	11:30
8	Homework A2 Comments	6:08
	Entire Playlist Including Demo of creating Database

Jim Mitchell

MS Access Demo – Buildings, Rooms, Sensors, Measurements

The second homework assignment asks you to build a database of sensors.  I’ll be showing an example in class (assuming there isn’t a snow problem) of building a Database that is aimed at recording measurements of any type in rooms of buildings, using sensors from a list that you’ve created.  It doesn’t exactly meet the requirements of the assignment, but should give you a good headstart on how to complete the assignment.  In some ways it goes well beyond the assignment requirements, though it certainly does not illustrate all of the capabilities of MS Access.

Video of making the database

There are five videos with a total length of 45 minutes that show you the steps.  The overview of these videos is on this DragonDrop Playlist.

The specific steps of the process are as follows – with links for each:

Description & Link	Length
Create Tables	9:38
Build Relations	5:44
Build Queries	11:01
Build Forms for Input	11:12
Create Report for Output	7:48

 

The purpose of the database

It’s always important to have a clear goal for a database, particularly a relational database.  Professionals have a well-developed method for defining the elements of database that relies on a mathematically rigorous theory, but that isn’t necessary for our fairly simple one.

In our case I define the goal as being able to record the following about a measurement:

• The measurement reading – a number
• The date and time it was taken
• The room and building in which it was taken
• The specific type of sensor used including: model & manufacturer (for your assignment you’ll want to extend what you record about the sensor greatly)

How the Database is Set Up

What is minimally necessary for a reasonable database to address this goal are four tables that have “relations” between them.  You could easily increase the number of tables (e.g. for “categories” of sensors and/or buildings and rooms) but this should be sufficient.  Those tables are:

• Building
• Room
• Sensor
• Measurement

The relation between these tables (you can see the fields too) is:

When you’re creating a database design it’s useful to think of what your goals are (in this case a record of measurements) and then work out from there to think about what is necessary to record for each measurement and how can I be sure that I enter the basic information only once.

Jim Mitchell

Paper Outlines – General Comments

Most of you produced good outlines with a clear path to the rough draft due in less than two weeks now.  Congratulations.

Some observations apply to many, but not all of the papers.

• Criteria for making judgments.  In many cases you’re planning to make judgments about either your own success in a specific task or about comparisons or trends.  I urge you to make your criteria for judging as explicit as possible early in the paper so it’s clear on what grounds you reach your conclusions.
• Reference to other industries.    In a number of cases it would be highly appropriate to look at industries that may have made changes in advance of the construction industry – e.g. autos, manufacturing, ship-building.
• Previous experience – If you’re undertaking a task (e.g. a BIM-related project) it’s important to be explicit about your own state of proficiency, experience and attitudes at the beginning (and end) of the project.
• Literature – be sure, as I’ve repeatedly urged, to look beyond your own experience.  For most papers a look at what others have reported would be highly beneficial.  In some cases this will be non-academic work such as trade journals and blogs.

Jim Mitchell

Interoperability – Week-5 Discussions

Once again you produced an interesting, generally well-written, set of discussion posts that showed even more awareness of what your colleagues had written.

• VistaBB shows me the number of posts that each person has visited (and probably read).  This week the lowest was 4, the highest (several) was 47, and many had read 10-15.  Several of you replied to multiple entries.

What follows are my reactions to a number of issues that you raised, not offered as “the answer”, but observations based on a reasonable amount of experience.

The Importance of Interoperability

• Most of you agreed that interoperability was a ‘good thing’ if it meant that one couldn’t be locked into a single vendor – as has happened in prior computer situations.
• A number of you were appropriately skeptical that the interoperability solutions addressed in this chapter were panaceas – for multiple reasons:
• Vendor greed – wanting exclusiveness to lock clients in
• Inherent technical difficulties with different (valid) approaches to the same problem
• The inevitable lag in producing a standard that can be adopted by all
• She sheer complexity of all the elements of a building – would it ever be possible to address them all
• My answer is “yes”, with mechanisms for addressing exceptions.
• Overblown claims of interoperability by vendors leading to errors and rejection by customers.
• This cries out for checking systems built into the transfer software mechanisms.  The software industry is quite good at this.
• My own suspicion is that someone is going to come up with a web-based system that provides the repository function.

The Variety of Customer Needs

• The chapter addresses, but few of you mentioned, the fact that there does not need to be full two-way data exchange in many situations.
• Technical consultants who can directly affect the structure of a building often do need two-way data exchange to allow the iterative design process you described quite well.
• Many other players, however, need only to be able to view the data and not to send it back directly.  That’s an easier problem that Eastman et. al. show has good tools available.

A Few Clarifications

• DXF is explicitly intended for data exchange.  It was developed by Autodesk (who has played games with it), but it’s well defined and has very successfully been used by others.  Characterizing it as proprietary is only 1/4 right I’d say.
• “File Exchange” is a fuzzy term.  Except where there is direct communication between programs (via the API usually), almost all data is exchanged via files.  The problems that many of you identified lie in the fact that there may be many versions of files, with conflicting information in them.  The goal of a repository system or a master-file is that there is one agreed-upon place that’s regarded as having the latest full information.
• A refinement of that, an important one, is that it’s desirable to keep track of alternates, old versions etc.  That too is possible with both these approaches.

Jim Mitchell