Terrestrial and Spaceborne Tests of the Equivalence Principle of Gravity Dr James D Phillips, Harvard Smithsonian Center for Astrophysics Since before Galileo Galilei, experimenters have used free fall to investigate gravity. The motivation has varied. In 2006, we test general relativity. GR is founded upon the Einstein equivalence principle, which states that all sufficiently small test objects, subject only to gravity, fall the same, independent of their size, composition, location and the …

http://www.youtube.com/watch?v=IVTKGS9FDZs&hl=en

Friends Link : Best HDTV canon dslr

Resonance fm is broadcasting a new audio work of mine this afternoon as part of Digestives, the ongoing art writing radio series from antepress. It’s going to be be aired on today at 4:30pm and repeated Friday 20 November at 7:30pm.

So I thought I should try to explain “comparability” very simply. Reading my previous posts, which were derived from larger texts, I spend a lot of time saying a lot of generalities, and I think the main point is getting missed. So here’s me getting down to brass tacks on the subject.

A computer CPU is a very basic electrical device. Send it a stream of electrons and a command to “add”, and it returns another stream of electrons representing a purely “mechanical” (i.e., unintelligent) electrical result. That CPU doesn’t know anything about semantics, or whether the switches and gates it opens and closes should appropriately be applied to those particular data streams. It just does what it was designed to do given that particular sequence of electron streams. If the streams are comparable before they get to the CPU, then the output will be meaningful. If they are not comparable, then the output (and being a CPU, there will be some output) will not be meaningful.

So the job of the software is to manipulate each symbol before presenting it to the CPU. In particular, the software needs to take each symbol and replace it with one that MEANS the same as the original symbol, but which will present itself to the CPU as COMPARABLE to the other symbols.

Comparability has to be put into the computer, through the software, by a human being. In particular, it is the human who understands when one data stream is not comparable to another, and it is the human being who writes the code to change one stream so that it becomes comparable to the other.

So what really are we talking about? Let me make a non-computer example to show the point.

2 + 00000010 = IV

If I take a pencil and write the above string of characters on a piece of paper, and show it to another computer programmer, after a few moments, I would expect that person to agree that this is a correct mathematical statement

 two plus two equals four

Part of the success of the person in understanding the original statement is that they are able to parse each symbol in the string, interpret the MEANING of each symbol, then translate each into COMPARABLE numeric ideas.

If the computer CPU could experience each symbol as I’ve written it (let’s agree that each of the symbols depicted here would have similar diversity of structure in the computer as they do here on the page), then we can immediately grasp what comparability is. The CPU does not know what the symbols mean, it cannot make the interpretation just by looking at the symbols as they are presented and come to the same conclusion as the human. 

If we look at what I, the human did, to provide you, the reader, with a more readable version of the equation, I replaced each symbol with another one that meant the same, but which appeared as mutually comparable symbols:

• 2   –>  two
• +  –>  plus
• 00000010  –>  two
• =  –>  equals
• IV  –>  four

Before the CPU can compare the symbol “2″ to the symbol “00000010″, they must both be replaced with two other symbols, each with the standard interpretation of “two”. These new symbols must be structured to flow through the CPU in such a way that their very structure is modified by the CPU to create a third symbol whose standard interpretation has the meaning “four”. The “plus” symbol must be translated into the CPU’s “ADD” instruction, and the “equals” symbol is represented by the stream of electricity leaving the CPU with the resulting symbol.

It’s raining dollars!  What would Frederic Bastiat have to say about this if he could speak to us from 1848?

As government regulations grow slowly, we become used to the harness – Judge Robert Bork

Frederic Bastiat

NEWS FLASH!

We interrupt our regular programming.  The President bans windows in order to benefit candle makers; candle production, he says, will stimulate the economy as long as candles aren’t melted by sunlight.  The administration also announces it will nationalize candle manufacturing, allow greedy wax suppliers only 10% of the money they are owed by the candle makers, plus grant a 30% share of Acme Candles, Inc.  to the UCMDWU (United Candle Mold Delivery Workers’ Union).   New York Times White House correspondent asks Press Secretary Roberty Gibbs what enchanted moment inspired this economic epiphany.

OK, I’ve got the facetiousness out of my system.  I wish I could take credit for this prescient concept.  I’ll admit to only my personal sarcasm in tying the philosophy of that remarkably witty proponent of freedom and liberty: Frederic Bastiat, (see link to Wikipedia entries from the pictures on the sidebar) to our current state of affairs.  Frederic Bastiat was a member of what was known as the French Liberal School in the 1840s (liberal as in the classical/original free market definition), warning of the folly of government intervention in the marketplace.  His parable of a fictitious petition by candle makers to the French government to eliminate windows in order to prevent candles from melting – thereby increasing economic prosperity by insuring the success of the candle industry (at the expense of the window industry…oops) – is a hilarious anecdote.  It also unfortunately illustrates the genesis of the president’s belief system.

Obviously above, I make reference to the bailout of GM, the perversion of the rule of law in throwing Chrysler bond holders to the wolves, and the artificial propping up of the UAW rather than normal bankruptcy pecking order.  Bastiat’s fable of altruistic but ultimately damaging marketplace intervention, is echoed consistently by the current administration’s adherence to this paradigm of unlimited spending by fiat justified by its immediate/short term effects on various and sundry interest groups.  In fact, Friedrich Hayek (see my previous two posts) said in a review of Bastiat that, according to 1930s economist John Maynard Keynes, the assumption of a multiplier effect (simply meaning a belief that the government can stimulate the economy by spending, producing a return greater than the cost of the stimulus; thereby increasing employment) on general economic prosperity would precisely mimic the argument of the candle makers!

Cash for clunkers (and maybe the upcoming Stimulus II cash for “cluckers” chicken farm bailout?) would most certainly fit neatly into these fallacies: money will do more good in the hands of the government, and it is the duty of government  to see that all get what they “deserve”.

Lastly, Frederic Bastiat’s landmark book: The Law has remarkable parallels to the economically damaging entitlement philosophies of the current congressional majority.  For example Bastiat says in the section The Results of Legal Plunder, “No society can exist unless the laws are respectable to a certain degree.  The safest ways to make laws respected is to make them respectable.”  This quote illustrates the current congress’s path towards a society in which greater than 50% of workers pay no taxes, and receive payments in the form of the Earned Income Tax Credit.  Therefore, this non-tax paying majority – the receivers of public services and governmental largess – are able to award themselves through the ballot ever increasing free goods and services from the minority: the tax payers/suppliers of public services and governmental largess.  I see no end to this increase in receivers, to include the resulting unconstructive inertia towards manufactured dependence.

So to bring my polemic to a close, I quote Bastiat one more time: “Legal plunder is identified as “… the law takes from some persons [what] belongs to them, and gives it to other persons to whom it does not belong…The person who profits from this law… will claim that the state is obligated to protect and encourage his particular industry…”

— Or nationality, ethnicity, income demographic, religion, color, blue collar, white collar, government employee, Woodstock museum, first time home buyer, union member, sexual preference, illegal immigrant, home in foreclosure, Wall St., Main St., small business, large business, self esteem damaging tatoo removers (I didn’t make this one up: see   http://www.mcclatchydc.com/226/story/63697.html), “green” energy producer, municipality, farmer, auto parts supplier, environmentalist, “too big to fail” bank and insurance companies, student, teacher, cop, mechanic, ethanol producer, the bicycle spoke hooker-uppers’ guild, donut shop owners’ amalgamated, and last but not least……….Acme Candles, Inc.

Comments on the blog con or pro most welcome.

At its most basic, the task of data integration from multiple source systems is one of recognizing the EQUIVALENCY and diagnosing the CONFLICTS among sets of symbols (the data) stored in each system’s data structures (syntactic media). Data integration is accomplished when the conflicts have been eliminated through TRANSFORMATION into new COMMON SYMBOLS which are COMPARABLE at both the syntactic and semantic levels.

The end result of data integration should be that SEMANTICALLY EQUIVALENT (or at least COMPARABLE) data structures become SYNTACTICALLY EQUIVALENT (COMPARABLE) as well. When this result is achieved, the data structures are considered COMPARABLY EQUIVALENT, and the data from the different source systems can be collapsed, combined or integrated correctly.

Structural Comparability

The issue can be characterized as one of the COMPARABILITY of data between systems.

• Syntactic Comparability is defined by the DATA TYPE and internal DATA STRUCTURE
• Semantic Comparability is defined by the CONCEPT or MEANING projected onto the data structure by the users of the source system
• Two data items are COMPARABLE if they share both SYNTACTIC and SEMANTIC COMPARABILITY

Typical Conflicts

Typical conflicts occur between and among the data structures originating from different sources.

• Syntactic Conflicts:
  • Data Type Conflicts
  • Structural Conflicts
  • Key Conflicts
• Semantic Conflicts:
  • Scale Conflicts
  • Abstraction/Formula Conflicts
  • Domain Conflicts
• Symbol Conflicts:
  • Naming Conflicts (Synonyms, Homonyms, Antonyms)

Syntactic Conflicts

• Data Type Conflicts – The same concept projected onto different physical representations. Example: different codes for the same set of options
• Structural Conflicts – For example, the same concept (referent) represented in one database by only a single attribute in one data source, but as a complete record of attributes in another source.
• Key Conflicts – Two systems using different unique keys for the same concept.
  • As an example, from a freight rail project I once worked, one set of systems represented a “station” by using the nearest Mileboard number to the station, while another set used an industry standard designator called a “SPLC” which was a code assigned to every reported station on all rail lines in North America.
  • In this example, the two different keys conflicted syntactically (e.g., Mileboard was an integer, SPLC was a string), and semantically (e.g., Mileboards are only meaningful within the context of a single railroad, being the distance from the origin of the line, while SPLCs are universal designators within the context of North America railroads).

Semantic Conflicts

• Scale Conflicts
  • Same data structure but representing different units. For example, corporate revenue represented as currency, but one using US Dollars and the other using CANADIAN Dollars.
• Abstraction/Formula Conflicts
  • Same data structure and “symbol”, but two different formulas used to calculate values.
• Domain Conflicts
  • Similar symbols and data structure, but two different sets of valid values or ranges of values.
  • For example, references to Customers in two systems each have assigned numeric identifiers, but the same customer has different assigned identifiers in each system.

Data Integration

The data integration specification documents how the symbols in two (or more) systems are similar and how they are different. The specification describes how the conflicts identified (under the rough categories described above) can be resolved to produce and combine comparable data symbols from each system. From a practical point of view, researching and documenting/describing the conflicts and similarities between symbols in two different systems is the same activity as defining the data integration specification which would be used to automate the integration.

What is “comparability“? Basically it is a relationship between two things. If two things are “comparable“, in general parlance, then they are similar in some aspects. They share common features or functions. They are not “equal” necessarily, as there may be important differences between them. In fact, it may be that the interesting aspect of the comparison made between the two objects is in their difference, more than in their similarity. However, a test for equivalence is a very common comparison to make for things that are comparable.

Typically, the comparison will be made with respect to some common constraint, from a particular point of view, or within a particular context. Any two things can be compared, although the meaningfulness an dutility of the comparison is not always guaranteed. The most meaningful/useful comparisons will occur within a context where the two things are strongly similar.

For a simple example, consider comparing ants and humans. In order to do this meaningfully, a context for comparison must be established, and a set of common properties must be recognized. Comparing the “wing span” property of ants an dhumans would be a meaningless comparison, since humans have no wings, and most ants do not either. Comparing the anatomy of an example of each type of creature might form a context where the property ”number of limbs” could generate a meaningful result.

Comparing the “strength” property of a human versus an ant may also be meainingless or at least misleading. The absolute strength of the human will be much higher than the absolute strength of the ant. However, comparing the “strength relative to weight” of each creature can tell us something much more interesting. The relative strength, where the weight of objects each creature can pick up is divided by the body mass (weight) of the creature.

Hence, while comparing absolute strength between ants and humans is meaningful, it is not terribly useful. Once the relative strength has been calculated, a meaningful and potentially useful comparison can be made, giving us an “apples to apples” comparison. By adjusting the strength property of each creature, we have created a comparison which is both meaningful and useful.

In this example, it is useful from the standpoint that the comparison is more understandable.

We have effected this improvement in the meaningfulness by establishing the context of comparison through the application of functions to the values of the creatures native properties. In other words, we have applied similar “conversion” functions in similar ways to the ant and human “strength” and “weight” properties to derive two new properties which are <em>more</em> comparable than each of the original values on their own.

The approach we took was to find where two things are analogous – where their similarties lie – and then to translate their analogous properties into meaningful and useful new values which can be compared.

The idea expressed by the term “comparability” implies that there will be similarities between the things compared. It also presupposes the expectation if not the a priori knowledge that there will be some differences, and that the differences between analogous properties can provide insight and knowledge.

Back in 1990, I was working on a contract with NASA building a prototype database integration application. This was the dawn of the Microsoft Windows era, as Windows 3.0 had just been released (or was about to be). Oracle was still basically a start-up relational database vendor trying to reach critical mindshare. The following things did not yet exist which we take for granted today (and even think of as kind of out dated):

• ODBC – allowing standardized access to databases from the desktop
• Microsoft Access and similar personal data management utilities
• Java (in fact most of the current web software stack was still just the twinkles in the eyes of their subsequent inventors)
• Message-based engines, although EDI techniques existed
• SOA and XML data formats
• Screen-scrapers, user simulators, ETL utilities…

The point is, it was still largely a research project just to connect different databases that an enterprise might be using. Not only did the data representational difficulties that we face today exist back in 1990, but there was also a complete lack of infrastructure to support remote connection to databases: from network communication protocols, to query interfaces, to security and session continuity functions, even to standardized query languages (SQL was not the dominant language for accessing data back then), and more.

In this environment, NASA had asked us to prototype a generic capability that would permit them to take user search criteria, and to query three different database applications. Then, using the returned results from the three databases, our tool was to generate a single, unified query result.

While generally a successful prototype, during a critical review, it became clear to NASA and to us that maintaining such an application would be horribly expensive, so the research effort was ended, and the final report I wrote was delivered, then put into the NASA archives. It is just as well too, because within five years, much of the functional capabilities we’d prototyped had started to become available in more robust, standards-based commercial products.

What follows is a handful of excerpts from the final report, which while now out of context, still expresses some important ideas about how software symbols actually work. The gist of the excerpt describes how software establishes the comparability and sometimes the equivalence of meaning of the symbols it manipulates.

In a nutshell, software works with memory addresses with particular patterns of voltage (or magnetic field direction) representing various concepts from the human world. Software is constantly having to compare such “structures” together in order to establish either equivalence of meaning, or to alter meaning through the alteration of the pattern through heavily constrained manipulations. The key operation for the computer, therefore, is to establish whether or not two symbols are “comparable“. If they are not comparability, quite literally, then the computer cannot reliably compare them and produce a meaningful result.

Without further ado, here are the important excerpts from the research study’s final report, which I wrote and delivered to NASA in November 1990.

“Database Integration Graphical Interface Tools, Future Directions and Development Plan”, Geoff Howe, November 1990

2.2 The Comparability of Fields

There are many kinds of comparisons that can be made among fields. In databases, the simplest level of comparability is at the data type level. If two fields have the same simple data type (e.g., integer, character, fixed string, real number), then they can be compared to each other by a computer. This level of comparability is called “basal comparability”. Thus, if fields A and B are both integers, they can be combined, compared and related in any way appropriate for two integers.

However, two elements meeting the qualification for basal comparability may still be incomparable at the next level, that of the syntactic level. The syntactic level of comparability is that level in which the internal structure of a field becomes important. Examples of internal formats which might matter and might be important at this level include date formats, identification code formats, and string formats. In order to compare two fields in different formats, one or the other of these fields would have to be converted into the other format, or else both would have to be converted into a third format. The only meaningful comparisons that can be made among the fields of a database or databases must be made at the syntactic level.

As an example, suppose A is a field representing a date in Julian format, and suppose B is a field representing a date in Gregorian format. Assuming that both fields are stored as integers, comparing these dates would be meaningless because they lack the same syntactic structure. In order to compare these dates one or the other of these dates would have to be converted into the other format, or else both would have to be converted into a third format.

Unfortunately, having the same syntactic structure is not a guarantee that two fields can be compared meaningfully by a computer process. Rather, syntactic comparability is the minimum requirement for meaningful comparison by computer process. Another form of comparability must be incorporated as well, that of semantic comparability. Semantic comparability is based on the equivalence of the meanings attached to the contents of some pair of data items. The semantics of data items are not readily available to computer processes directly; a separate description in some form must be used to allow the computer to understand the semantic equivalence of concepts. Once such representation is in place, the computer should be able to reason over the semantic equivalence of concepts.

As an example of semantic comparability consider the PCASS fields, ITEM PART NUMBER from the FMEA PARTS table of the PCASFME subsystem, and CRIT_LRU_PART_# from the CRITICAI LRU table of the PCASCLRU subsystem. Under certain circumstances, both of these fields will hold the part numbers of “line replaceable units” or LRUs. Hence, these fields are semantically comparable. Given a list of the contents of ITEM PART NUMBER, and a similar list for CRIT LRU PART #, the assumption can be made that some of the same “line replaceable units” will be referenced in both lists.

Semantic comparability is useful when integrating data from different databases because it can be used to indicate the equivalence of concepts. Yet, semantic comparability does not imply syntactic comparability, and thus both must be present in order to satisfactorily integrate the values of fields from different databases. A definition of the equivalence of fields across databases can now be offered. Two fields are equivalent if they share the same base type; if their internal syntactic structure is the same; if their representational domains are the same; and if they represent the same concept in all contexts.

2.3 Heterogeneous Data Dictionary Architecture

 The approach which seems to have the most documentary support in the research for solving the integration of heterogeneous distributed databases uses a two-tiered data dictionary to support the construction of location-independent queries. The single data dictionary, used by both the single-site database management system, and the homogenous distributed environment, is split in two across the physical-conceptual boundary. This results in a two-level dictionary where one level describes in detail the physical fields of each integrated database, and the second level describes the general concepts stored across systems. For each unique concept represented by the physical level., there would be an entry in the conceptual level data dictionary describing that concept. Figure 2 shows the basic architecture of the two level data dictionary.

As an example of the difference between the conceptual and physical data dictionary levels, consider again the field PCASFME.FMEA PARTS.ITEM PART NUMBER. This is the full name of the actual field in the PCASS database. The physical level of the data dictionary would have this full name, plus the details of how this field is represented (character string, twelve places long). The conceptual level of the data dictionary would contain a description of the contents of the field, and a conceptual field name, “line replaceable unit part number”. Other fields in other tables of PCASS or in other databases may also have the same meaning. This fact poses the problem of mapping the concept to the physical field, which will be described below. Notice, however, how much easier it would be for a user to be able to recall the concept “line replaceable unit part number”, as opposed to the formal field name. This ease of recall is one of the major benefits of the two-level data dictionary being proposed. Two important relationships exist between the conceptual and physical data dictionaries. One of the relationships between fields of the conceptual level data dictionary and fields of the physical level data dictionary can be characterized as one-to-many. That is, one concept in the conceptual data dictionary could have many physical implementations. Identification of this type of relationship would be a matter of identifying and recording the semantic equivalences across system boundaries among fields at the physical level. All physical fields sharing the same meaning are examples of this one-to-many relationship.

Within the PCASS system, the concept of a line replaceable unit part number” occurs in a number of places. It has already been mentioned that both the ITEM PART NUMBER field of the FMEA_PARTS table, and the CRIT LRU PART # field of the CRITICAI_LRU table, represent this concept. The relationship between the concept and these two fields is, therefore, one-to-many.

The second type of relationship which may also be present, depending on the nature of the existing databases, relates several different concepts to a single field. This relationship is characterized as “many-to-one”. Systems which have followed strict database design rules should result in a situation where every field of the database represents one and only one concept. In practical implementations, however, it is often the case that this rule has not been thoroughly implemented, for a variety of reasons. Thus it is more than likely, especially in large database systems, that some field or set of fields may have more than one meaning under various circumstances. Often, these differences in meaning will be indicated by the values of other associated fields.

As an example of this type of relationship, consider the case of the ITEM PART NUMBER field of the PCASS table FMEA PARTS in the FMEA dataset one-more time. This field can have many meanings depending on the value of the PART TYPE field in the same table. If PART TYPE is set to “LRU”, the ITEM PART NUMBER field contains a line replaceable unit part number. If PART TYFE is set to “SRU”, the ITEM PART NUMBER field actually contains a shop replaceable unit part number. Storing both kinds of part numbers in the same structure is convenient. However, in order to use the ITEM PART NUMBER field properly, the user must know how to read and set the PART TYPE field to disambiguate the meaning of any particular instance of the record. Thus, the PART TYPE field in the physical database must hold either an “SRU” or “LRU” flag to indicate the particular meaning desired at any one time.

In the heterogeneous environment, it may be possible to find a different database in which the same two concepts which have been stored in one filed in one database, are stored in separate fields. It may in fact be possible that in one or more databases, only one of the two concepts has been stored. This is certainly the case among the separate data sets which make up the PCASS system. For example, in the PCASCLRU data set, only the “line replaceable unit part number” concept is stored (in the field, CRIT_LRU_PART_#). For this reason, the conceptual level of the data dictionary must include both concepts. Then there must be some appropriate construct within the data definition language of the data dictionary system which could express the constraints under which any particular field had any particular meaning. In order to be useful in raising the level of data location transparency, these conditional semantics must be entered into the data dictionary using this construct.

It is obvious now that the relationship between entries in the conceptual data dictionary and the physical data dictionary is truly many to many (see Figure 3). To implement such a relationship, using relational techniques, a third major structure (in addition to the set of tables supporting the conceptual data dictionary and the set of tables supporting the physical data dictionary) must be developed to mediate this relationship. This structure is described in the next section.

2.3.1 Conceptual – Physical Data Mapping

As an approach to implement this mapping from conceptual to physical structures, a table must be developed which relates every concept with the fields which represent it, and every field with the concepts it represents. This table will consist of tautological statements of the semantic equivalence of physical fields to concepts. A tautology is a logical statement that is true in all contexts and at all times. In thiis approach, the tautologies take the following form (please note that the “==” operator means “is semantically equivalent to”, not “is equal to”):

 normalized field f == field a from location A

 The normalized field f of the above example corresponds directly to an entry in the conceptual data dictionary. We call the field, f, normalized to indicate that it is a standard form. As will be described later, the comparison of values from different databases will be supported by normalizing these values into the representation described in the conceptual data dictionary for the normalized field.

Conditional semantics must now be added to the structure to support discussion. Given a general representation for a tautology, conditional semantics may be represented by adding logical operations to the right side of the equivalence. Assume that a new database, D, has a field, d1, which is equivalent to the normalized field, f, but only when certain other fields have specific values. Logically, we could represent this in the following manner:

normalized field f == field d1 from location D iff
field d2 from location D = VALUE1 AND
field d3 from location D = VALUE2 AND …
field dn from location D opn VALUEn

 In more general terms, the logical statement of the tautology would be as follows:

 R == P iff  E

where R is the normalized field representation, P is the physical field, and E is the set of equivalence constraints which apply to the relation. In our part number example, the following tautologies would be stored in the mapping:

Line Replaceable Unit Part Number == PCASFME.FMEA.PARTS.ITEM_PART_NUMBER iff PCASFME.FMEA.PARTS.PART_TYPE = “LRU”

Shop Replaceable Unit Part Number == PCASFME.FMEA.PARTS.ITEM_PART_NUMBER iff PCASFME.FMEA.PARTS.PART_TYPE = “SRU”

Line Replaceable Unit Part Number == PCASCLRU.CRITICAL_LRU_CRIT_LRU_PART_#

The condition statements are similar to condition statements in the SQL query language. In fact, this similarity is no accident, since these conditions wilt be added to any physical query in which ITEM PART NUMBER is included.

From a user’s point of view, implementing this feature allows the user to create a query over the concept of a line replaceable unit part number without having to know the conditions under which any particular field represents that concept. In addition, by representing the general – concept of a line replaceable unit part number, something the user would be very familiar with, this conceptual mapping technique has also hidden the details of the naming conventions used in each of the physical databases.

…

2.4.2 Integrating Data Translation Functions Into the Data Dictionary

In the simplest case, the integration of data translation functions into the data dictionary would be a matter of attaching to the data mapping tautologies described above a field which would store an indication of the type of translation which must occur to transform a result from its Location-specific form into the normalized form. This approach can be simplified further by allowing translations at the basal level to be identified by the source and target data types involved, and not recording any further information about the translation. It may not be unreasonable to assume that in certain well-defined domains, most of the translation functions required would be either identity functions or simple basal translation functions.

It is now possible to define completely the data structure required to store any arbitrary physical-conceptual field mapping tautology. The data structure would consist of the following parts:

• concept field – a single, unique concept which the physical projection represents
• normalized – a reference to the conceptual data dictionary entry used to represent the concept
• physical projection – the field or set of fields from the physical data dictionary which under the conditions specified in the equivalence constraints represent the concept
• equivalence constraints – the conditions under which the physical projection can be said to represent the concept
• translation function – the function which must be performed on the physical projection in order to transform it into the normalized format of the normalized field

The logical statement of the tautology would be as follows:

R = Ft (P) iff E

where R is the normalized field representation, Ft is the translation function over the physical projection, P, and E is the set of equivalence constraints which apply to the relation. The exact implementation of this data structure would depend on the environment in which the system were to be developed, and would have to be specified in a physical design document. Note that instead of the “==” sign, which was defined above as “is semantically equivalent to”, has been replaced by “=” which means “is equivalent to”, and is a stronger statement. The “=” implies that not only is the left side semantically equivalent to the right, but it is also syntactically equivalent.

Relax. This is a way of writing. It is imagined. The scene is a room in the White House, setting is informal. The President has asked if I prefer that and I do.

President Obama: OK. What is it.

An Obama Doctrine, sir. You said change the world. That resonated. It still does. You agree with Derrida and countless others who have said that we need a change beyond our spiral repetition of the past. The Obama Doctrine would spell this out.

President Obama: (Smiles)

I know. I know. You’ve already laid out the biggest change. That diplomacy can work. It is no longer just a step. It means to be the last step. Negotiation.

President Obama: Yes.

The most radical element of an Obama Doctrine would be to affirm, and stand by, equivalence in the event of attack.

President Obama: Lex talionis.

Yes, sir.  If we had had an Obama Doctrine after 9/11 we would have saved untold lives on all sides. Though the law is very old, it has never been practiced in conflicts between nations.

President Obama:  What relevance does this have right now?

You would signal an intention to wind down, not up. You would negotiate with the enemy.

President Obama: Is that all?

No, sir. The Obama Doctrine is a call to the evolution of humankind from a war to a peace-footing. You cannot speak of global prosperity without acknowledging our current enslavement to military thinking and military-industrial action.

President Obama: I have that Nobel Speech to make

That is where the Obama Doctrine gets launched.

President Obama: We have an ongoing conflict with an enemy that wills to inflict as much damage as it can on Americans.

If we practice equivalence they will have to acknowledge that the world has changed. You have already set the stage with your Cairo speech. Secretary Clinton conveys a similar intent.

President Obama: Anything else?

Yes. We need to say that the individual is sacrosanct. If we say this, then we must support freedom of movement. We must say that this freedom applies in particular to victims of oppression.  We must work toward freedom of movement as a human right.

President Obama: I am trying to see where this would lead.

McCain and others would see this as the gift that keeps on giving. You would be skewered by the right. You would incur the wrath of your generals. You would risk your Presidency.

President Obama: Your solution?

Argue it out. Who are we fighting? What do they want? We can argue persuasively that in our world we do not support the creation of  nations or regions under one religion — this is what Al Queda wants and will not get. We can argue persuasively that we are not the enemy — but not if we continue to essentially participate in civil wars in other countries. We can argue that this is part of a broad move to begin to accept control over our lives.

President Obama: I’m thinking.

Sir, I believe in my heart that your Presidency will succeed only if you move in this direction. The other way is quicksand.

President Obama:  I know.

People out there are saying you have no gut feeling either way. Then they act as though the only way to go is to keep up the fight. The fight is impossible. You are fighting the people whose allegiance you want to win. Your gut would be truly engaged building a world beyond thousands of years of warfare and the celebration of violence.

President Obama:  OK. I’ll sleep on it. There is a way.

Thank you, sir.

President Obama: Want to look around.

No, sir. I appreciate your time.

President Obama: (Sighs, rises)

(Rises)

President Obama:  I wish everything was that easy.

You know it isn’t easy,  sir. It never has been for anyone who ever changed things.

President Obama: You’re sounding like me.

Yep.

President Obama: Get up and go.

Yes, sir.

President Obama: The time is short.

It is, sir.

President Obama: Good night.

Reconnaître la fraction

Un excellent exercice trouvé sur le site de Michel Neroucheff

(clique sur la vignette ci-dessus)

Trois exercices sur le site Echecs et Maths :

Trouve le dénominateur

Trouve la fraction

Attention, le suivant est difficile,

on n’a pas encore fait cela en classe (27/10/09).

Trouve la fraction équivalente

I come back to these diagrams very often.

Tedium (Dullness, passiveness owing to slowness)…

“Malgré une récente décision historique du conseil du barreau de Prague, la bataille [pour faire reconnaître ses diplômes dans son pays d’origine], qui mêle rigidité administrative et applicabilité du droit communautaire, n’est pas encore gagnée.” [Lire la suite / Radio Prague]

Tomorrow afternoon’s Digestives broadcast on Resonance FM is Holidays Vocabulary, a new work of mine based on the sound files I unearthed on an old dictaphone of mine last month. It’s an experiment in translation.

Holidays Vocabulary airs tomorrow at 4:30pm and is repeated this Friday at 7:30pm, and you can listen by clicking the ‘Listen Now’ mp3 stream at www.resonancefm.com, or tune in to 104.4fm inside London. Afterwards it will be available to download as a podcast at www.antepress.co.uk.

Terrestrial and Spaceborne Tests of the Equivalence Principle of Gravity Dr James D Phillips, Harvard Smithsonian Center for Astrophysics Since before Galileo Galilei, experimenters have used free fall to investigate gravity. The motivation has varied. In 2006, we test general relativity. GR is founded upon the Einstein equivalence principle, which states that all sufficiently small test objects, subject only to gravity, fall the same, independent of their size, composition, location and the …

http://www.youtube.com/watch?v=mHH42QbP9Jo&hl=en

Related : Best HDTV For You Dance Ware Shop hdtvcables

Here’s a short extract of What To Do, a 35 minute ‘blank talk’ that flattens its own text as it goes along.

Just for fun, below are some rough copies of the diagrams, some of which eventually appear in the talk itself.

A simple explanation.

The speed of light is not only constant but it is also limiting. That means that nothing can go faster than light in the universe as we observe it.

Normally, we can make a body go faster and faster by adding energy to it. (Force applied on a body times the distance that it moves through = work done on that body).

What happens if you try to accelerate a  body is already at the speed of light, by applying a force on it?

• Then all the energy you add to it, gets added to its mass.
• If it maintains its density it swells and becomes very big.
• If it maintains its volume it becomes very dense.

Mass and Energy are 2 states of the same thing.

May be the above explanation helps you know how the energy intensive universe became ‘massive’ – part mass and part energy.

Because energy = mass times velocity of light squared., even a little bit of mass equals a lot of energy. (remember the atomic bomb?)

The compound statement P <=> Q is only true when both P AND Q are the same.

P <=> Q can be said in the following ways:

P is equivalent to Q

P if and only if Q

P is a necessary and sufficient condition for Q

There is some assumption that feminism is this one giant entity, but that’s rarely true of any big social or political movement. We don’t always agree. I’m going to show just one of the points of separation – it’s oversimplified, and you know how I hate generalized dichotomies. But I want to explain the difference between “equality” feminism and “equivalence” feminism as well as I can within this space. They are both feminism, do not mistake me – they represent several different waves of feminism. I simply do not agree with one of them, but I will try to explain them as unbiased as I can.

Equality means treating men and women the exact same way, with the same respect, because most to all of gender and sex qualities are more taught than innate. It’s a matter of treating people like people rather than men and women. It’s realizing that there’s a vast spectrum of gender and sexual experience, that being a person shouldn’t be limited, that women can have “masculine” traits and men can have “feminine” traits and that they shouldn’t be treated as different just because of their biological sex. It’s realizing that biological sex itself is quite arbitrary (especially when you look at the exceptions… try to categorize an intersexed individual). It’s realizing that even a deviation of .01% in a world population this huge is quite an exception. Equality is not a cry for sameness, but for recognition of the diversity of human experience.

Equivalence is paying attention to biological determinism wherein biological differences mean that women are one way and men are another. They are treated differently according to their own strengths. Men are more logical, therefore it’s natural that there are more men in jobs that require reason. Women are more emotional, therefore it’s natural they dominate caregiver jobs. This doesn’t mean treating women like doormats, by any means. It means that women should embrace what strengths that are inherent to them and not try to be something they’re not (i.e. they shouldn’t try to be like men, they shouldn’t try to be the same). I want to add that feminists that adhere to the “equivalence” feminism can also be career women. They can be leaders. They can be smart. Just like there are housewives who are proponents of “equality.” It’s not cut-and-dried goodies and baddies. Equivalence enhances the accepted understanding of differences and embraces them. I also believe that they perpetuate a damaging dichotomy and ignore the plethora of exceptions.

Part of me understands where the “equivalence” mindset comes from. The whole mentality of “You look different, therefore you must also feel and think differently” and “We look similar, so we must be similar in thought and emotion.” It’s false intuition. It fails to recognize that everyone looks different than everyone else, everyone has different experiences that make them who they are. And identical twins can be vastly different. It’s not about biology, although some aspects of biology can affect your experiences. But even biological “imperatives” are not imperative. Not all women can have children, not all women have cramps or PMS, not all women go through terrible menopause, not all women have periods… there’s no such thing as a universal woman’s experience, so why is there an expectation that there’s a certain sameness about all females?

I am in no way the spokesperson of “equality” feminism, but this is my understanding of the feminist split between equality and equivalence.

The things are back where they came from now, only red. There’s a nasty hierarchy now among my things. The painted things indicate the nakedness of all the other things. Are the red things fake, or are they the only things that are real, because they acknowledge themselves? They look smug about it.

Precipice.

I came across this picture today while I was trying to find the painting of Susannah and the Elders Diderot describes in his Salon reports. Jacopo Tintoretto’s version of events is the painting in this photo – it isn’t the one I was looking for, but the photo illustrates very happily my interest in the painting’s surface as a kind of pivot for the beholder’s gaze.

(photo credit: PHILIPPE DESMAZES/AFP/Getty Images)

A short commentary text I wrote this week expands:

Finding herself observed Susannah conceals herself from the elders with her veils,

“with the result that in order to escape the elders’ gaze she exposes herself entirely to the eyes of the beholder. This composition is very free and no one is offended by her. It is because the obvious intention saves everything and because the beholder is never part of the subject.” (Fried, M. quoting Denis Diderot’s Salon Report in Absorption and Theatricality: Painting and the Beholder in the age of Diderot; Michael Fried, U Cal Press 1980, p. 97)

The self-contained gaze, which is both cast and sated within the plane of the painting, seals off the image from the beholder standing before the artwork and strips her unclothed state of the currency it had in the depicted world. “L’art n’y est plus”14: the painting excludes the operation of the beholder and completes itself within the depicted plane.

But a reversal takes place, which pivots about the plane of representation. Specifically because the real-world beholder is never part of the subject, the erotic currency of the figure’s nakedness is replenished in the real world as her intentions are sealed within the depiction.

It is that the process of manufacture generates through moves of increasing precision a certain articulate outline, which contains and does not constitute the substance of its object. It is that manufacture contains the lack of its object. It is that the process of manufacturing a utensil differs from the process of using it, and that using also contains the lack of its object. That although they produce and are produced from the same object, the two processes are not symmetrical. That there are similarities nevertheless, because the material qualities of the utensil demand specific sympathies that determine its manipulation.

This is Blanchot’s The Most Profound Question as it approaches my work. It’s probably going to precede the Kafka text I posted yesterday in a list of texts accompanying the critical commentary I’m writing about the work I’ve done this year.

The question form “is speech that is accomplished by having declared itself as incomplete” (p.12). The particular incompleteness of the interrogative offers a “richness of possibility” by which we “give ourselves the thing and we give ourselves the void that permits us not to have it yet”. (p. 12) The void contained in the question form is indeed a lack -

“but this lack is of a strange kind. It is not the severity of negation: it does not do away with, it does not refuse. [...] The word ‘is’ is not withdrawn; it is only lightened, rendered more transparent, committed to a new dimension”. (p. 13)

This lightness is reflected grammatically in English question formation when the word ‘is’ raises from its original position to the beginning of the sentence, illuminated like the heightened brilliance of a star just before it dies (p. 13). In its new position, the ‘is’ of the sentence – the verb that asserts the sentence’s ‘being’ – “abandon[s] its part of resounding affirmation, its decisive, negating part” and opens the sentence out into pure possibility “in such a way that, in this opening, the sentence seems no longer to have its center in itself but outside itself – in the neutral.” (p. 13)

With the centre of the sentence shifted outside of itself, the question form is disengaged from the bald statement of fact presented by an affirmative answer. ‘The sky is blue’ is quite different from the form ‘Is the sky blue? – Yes’ (p. 13). The affirmative misrepresents the centre, presuming it to be within the sentence rather than elsewhere, and in affirming the truth conditions of this centre it truncates the question’s potential and closes it into the singularity of a thing.

“Transformed for an instant into pure possibility, the state of things does not return to what it was. The categorical Yes cannot render what was, for a moment, only possible; still more, it withdraws from us the gift and the richness of possibility since it now affirms the being of what is, but affirms it in response, thus indirectly and in a manner that is only mediate.” (p. 13)

The immediacy of direct relation is denied between question and answer because they operate in irreconcilably separate spaces: the external/neutral and the concentric/specific.