Archive for October, 2011

Do-It-Yourself Seismic Screening

Thursday, October 20th, 2011

In May 2010 I performed an exercise in do-it-yourself seismic screening of an existing building.

I used 2 methods: FEMA 154 and P25. These methods are both intended for a broad class of users, such as building owners. One term used to describe such methods is “rapid visual screening”. The idea is that people can estimate the likely performance of their building in a major earthquake and then make an informed decision on whether to invest in a professional seismic assessment of the building.

These methods are somewhat difficult to apply, because they require classifications that are not clearly defined. Since performing the exercise, I have not detected any progress in the availability to the public of well-documented, easy-to-apply do-it-yourself seismic screening tools.

I discussed this problem with some engineers at the 2011 PEER Annual Meeting. Some are working on new and better screening methods. One engineer referred me to the ASCE 31 standard for the seismic assessment of existing buildings. Its current version, ASCE 31-03, was published in 2003. It defines 3 “tiers” of seismic assessment. In 2008 it was critically reviewed by 3 engineers, who argued that it has fundamental defects and will be “promoting the expenditures of large sums of money on inappropriate engineering analysis”. Whether it is a worthy method or not, it does not seem to be a method designed for the owners or users of buildings who wish to perform do-it-yourself screenings. For example, let’s assume that I have correctly classified Berkeley Town House’s building as a C2 building. Then the Tier 1 checklist for this building requires me to decide whether the building complies with this criterion: “The stiffness of the lateral-force-resisting system in any story shall not be less than 70 percent of the lateral-force-resisting system stiffness in an adjacent story above or below, or less than 80 percent of the average lateral-force-resisting system stiffness of the three stories above or below for Life Safety and Immediate Occupancy.” Decisions like this can’t be read straight off the building drawings.

Life (for those surviving) after a major earthquake will also depend on the entire region’s response. For those in the Bay Area, one of the talks at the PEER meeting gave a forecast of this. You can watch Janielle Maffei’s talk on “The Coming Bay Area Earthquake—2010 Update” to learn more about the expected damage and the recent efforts to mitigate it in advance.

PanLex, Copyright, and Licensing

Friday, October 7th, 2011

PanLex is a compilation of lexical data and a set of procedures facilitating the interrogation and modification of the data.

In other locations I have commented on the issues of intellectual property that can arise from a project such as PanLex. These other comments include “PanLex as Intellectual Property”, “Source Citation in PanLex”, and a paragraph in my report to the 1 June 2011 meeting of the Utilika Foundation board of directors, where I wrote:

Intellectual-property claims impose some limits on the expansion of PanLex. The creators of some resources assert rights that, taken literally, would prohibit a person reading a resource from later even making use of what he or she had learned from it. Other resources are in the public domain. Between these extremes, many resources have been published subject to explicit or implicit copyright and various claims and restrictions, including various copyleft-type licenses and prohibitions of commercial use. The above-mentioned metadata that we record for resources used, or to be used, for PanLex include data on intellectual-property claims and permissions. In directing the PanLex project I take such claims into account, insofar as they appear to be understandable and enforceable, but, in most cases, I believe the owners of lexical resources could not prohibit the foundation from recording in PanLex information contained in those resources. This belief is based on the understanding that what we do with a resource is to record some of the facts asserted in it, in a novel (recoded, normalized, structured, interoperable) form. (In other words, PanLex doesn’t copy source X, but instead tells the world that some user of PanLex who has consulted source X claims that source X either states or implies that word Y is a translation of word Z.) In addition, I believe that PanLex typically advances the purposes of a contributing resource’s creator by making the facts contained in the resource more accessible and usable and referring users of those facts to the original resource for more detailed information. Until now, no claimant has asked us to remove facts based on a resource from PanLex. Some (e.g., LINCOM GmbH and SIL International) have expressly approved our use in PanLex of some or all of their data. However, some possessors of resources have demanded payment for providing easily processable versions for use in PanLex, and others have refused to provide such versions at all. The inclusion of funds for legal services in the 2012 budget reflects an assumption that intellectual-property issues, as well as contractual issues more generally, will likely become more complex as the PanLex project progresses.

One of the related issues is the protection of databases as compilations. A discussion of this issue by Daniel Tysver describes the competing originality and effort criteria for making a database copyrightable. Some compilers of databases in some jurisdictions have found copyright claims unenforceable because their databases were unoriginal. Telephone directories are the classic example.

Now there is litigation on another type of arguably unoriginal database: a collection of data on time zones that much of the world has come to depend on. There is much discussion on the merits of the claim. The outcome of this lawsuit may further clarify the limits of copyright protection on data like those in PanLex.

Raceway Recommendation

Sunday, October 2nd, 2011

I have just installed about 40 feet of raceway to enclose low-voltage Ethernet and telephone cables. The raceway that I used was quite satisfactory, so I recommend it.

The manufacturer is Premiere Raceway Products, Inc., of Hillsborough, New Jersey. The product is named WireHider Cord Cover. It is a 2-piece product. The back is a 4-foot-long channel with a double-stick foam backing for mounting and soft curled leaves running the length of the channel that hold the wires inside the channel. The front is a cover that snaps onto and around the back. To join lengths of the raceway at corners, one can use connectors that snap over the fronts with about a half-inch overlap. The product identifiers of the items that I purchased were:

FWH-12916 = back

FCL-22916 = front

FRA-32411 = sideways right-angle (vertical to horizontal on same wall)

FIC-42411 = inside corner

Here are some good features of this product line:

  1. Both the back and the front cut easily with a hacksaw.
  2. The front snaps easily onto the back, and pulls fairly easily off the back.
  3. The leaves (called flexible tabs by the manufacturer) keep the wires inside the back channel during installation.
  4. Stuffing the wires between the leaves into the back channel is fairly easy.
  5. Because the connectors overlap the covers, it isn’t necessary to cut the covers to a precise length.
  6. Because the covers have sides that extend all the way to the wall, it is not necessary to cut the backs so they end exactly where the fronts end; the fronts can extend beyond the ends of the backs.

The only caveat I would offer is that the connectors don’t have the same degree of whiteness as the cover lengths; the connectors are more gray.

I purchased this product from Online Raceway. Offering a 10% new-customer discount and free shipping on orders of $75 or more, it was the least expensive vendor I found. My order was shipped promptly and arrived in good condition.