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+
+Network Working Group S. Nelson
+Request for Comments: 2077 LLNL
+Category: Standards Track C. Parks
+ NIST
+ Mitra
+ WorldMaker
+ January 1997
+
+
+ The Model Primary Content Type for
+ Multipurpose Internet Mail Extensions
+
+Status of this Memo
+
+ This document specifies an Internet standards track protocol for the
+ Internet community, and requests discussion and suggestions for
+ improvements. Please refer to the current edition of the "Internet
+ Official Protocol Standards" (STD 1) for the standardization state
+ and status of this protocol. Distribution of this memo is unlimited.
+
+Introduction
+
+ The purpose of this memo is to propose an update to Internet RFC 2045
+ to include a new primary content-type to be known as "model". RFC
+ 2045 [1] describes mechanisms for specifying and describing the
+ format of Internet Message Bodies via content-type/subtype pairs. We
+ believe that "model" defines a fundamental type of content with
+ unique presentational, hardware, and processing aspects. Various
+ subtypes of this primary type are immediately anticipated but will be
+ covered under separate documents.
+
+Table of Contents
+
+ 1. Overview............................................. 2
+ 2. Definition........................................... 2
+ 3. Consultation Mechanisms.............................. 4
+ 4. Encoding and Transport............................... 5
+ 5. Security Considerations Section...................... 6
+ 6. Authors' Addresses................................... 7
+ 7. Expected subtypes.................................... 7
+ 8. Appendix............................................. 9
+ 9. Acknowledgements..................................... 13
+
+
+
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 1]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+1. Overview
+
+ This document will outline what a model is, show examples of models,
+ and discuss the benefits of grouping models together. This document
+ will not directly deal with the intended subtypes since those will be
+ covered by their separate registrations. Some immediately expected
+ subtypes are listed in section 7.
+
+ This document is a discussion document for an agreed definition,
+ intended eventually to form a standard accepted extension to RFC
+ 2045. We are also targeting developers of input/output filters,
+ viewer software and hardware, those involved in MIME transport, and
+ decoders.
+
+2. Definition of a model
+
+ A model primary MIME type is an electronically exchangeable
+ behavioral or physical representation within a given domain. Each
+ subtype in the model structure has unique features, just as does each
+ subtype in the other primary types. The important fact is that these
+ various subtypes can be converted between each other with less loss
+ of information then to that of other primary types. This fact groups
+ these subtypes together into the model primary type. All of the
+ expected subtypes have several features in common and that are unique
+ to this primary type.
+
+ To loosely summarize: models are multidimensional structures composed
+ of one or more objects. If there are multiple objects then one
+ object defines the arrangement/setting/relationship of the others.
+ These objects all have calibrated coordinate systems but these
+ systems need not be in the same units nor need they have the same
+ dimensionality. In detail:
+
+ 1. have 3 or more dimensions which are bases of the system and
+ form an orthogonal system (any orthogonal system is sufficient).
+
+ This system is specifically defined in terms of an orthogonal
+ set of basis functions [for a subspace of the L^2 function space]
+ over a coordinate system of dimension 3 or more. Note that this
+ does not preclude regular skewed systems, elliptical coordinates,
+ different vector spaces, etc.
+
+ 2. contain a structural relationship between model elements.
+
+ 3. have scaling or calibration factors which are related to physical
+ units (force, momentum, time, velocity, acceleration, size, etc.).
+ Thus, an IGES file will specify a building of non-arbitrary size,
+ computational meshes and VRML models will have real spatial/
+
+
+
+Nelson, et. al. Standards Track [Page 2]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ temporal units. This allows for differing elements to be combined
+ non-arbitrarily.
+
+ 4. Models can be single objects or composed of a collection of
+ objects. These normally independent objects are arranged
+ in a master/slave scenario so that one object acts as the
+ reference, or primary object, which defines how the other
+ objects interrelate and behave. This allows for the creation
+ of mathematical, physical, economic, behavioral, etc. models
+ which typically are composed of different elements. The key is
+ in the description: these types describe how something
+ "behaves"; contrasted to typical data types which describe
+ how something "is".
+
+ The inclusion of this "collective" system works similar to the
+ Email system's multipart/related type which defines the actions
+ of the individual parts. Further specification of the model/*
+ subtypes utilizing these properties is left to the subtype
+ authors.
+
+ With these assumptions:
+
+ a. the default dimensionality will be spatial and temporal (but
+ any are allowed).
+
+ b. it is presumed that models will contain underlying structure
+ which may or may not be immediately available to the
+ user. (fluid dynamics vector fields, electromagnetic
+ propagation, interrelated IGES dimensional specifiers, VRML
+ materials and operators, etc.)
+
+ c. it is assumed that basis set conversion between model domains
+ is lossless. The interpretation of the data may change but
+ the specification will not. i.e. convert the model of the
+ U.S.A. Gross Domestic Product into a VRML model and navigate
+ it to explore the variances and interrelationships. The model
+ has many dimensions but also "passages" and "corridors"
+ linking different parts of it. A similar situation is true
+ for meshes and CAD files. The key is identifying the basis set
+ conversion which makes sense.
+
+ d. models are grouped to assure LESS loss of information between
+ the model subtypes than to subtypes of other primary
+ types. (i.e. converting a chemical model into an image is
+ more lossy than concerting it into a VRML model).
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 3]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ Items c and d above define the grouping for model similar to the way
+ that "images" and "videos" are grouped together; to assure less loss
+ of information. Obviously converting from a GIF image to a JPEG
+ image looses less information than converting from a GIF image to an
+ AU audio file.
+
+3. Consultation Mechanisms
+
+ Before proposing a subtype for the model/* primary type, it is
+ suggested that the subtype author examine the definition (above) of
+ what a model/* is and the listing (below) of what a model/* is not.
+ Additional consultations with the authors of the existing model/*
+ subtypes is also suggested.
+
+ Copies of RFCs are available on:
+
+ ftp://ftp.isi.edu/in-notes/
+
+ Copies of Internet-Drafts are available on:
+
+ ftp://ftp.ietf.org/internet-drafts/
+
+ Similarly, the VRML discussion list has been archived as:
+
+ http://vrml.wired.com/arch/
+
+ and discussions on the comp.mail.mime group may be of interest.
+ Discussion digests for the existing model/* subtypes may be
+ referenced in the respective documents.
+
+ The mesh community presently has numerous different mesh geometries
+ as part of different packages. Freely available libraries need to be
+ advertised more than they have been in the past to spur the
+ development of interoperable packages. It is hoped that by following
+ the example of the VRML community and creating a freely available
+ comprehensive library of input/output functions for meshes [11] that
+ this problem will be alleviated for the mesh community. A freely
+ available mesh viewer conforming to these standards is available now
+ for various platforms. Consulations with the authors of the mesh
+ system,
+
+ http://www-dsed.llnl.gov/documents/tests/mesh.html
+
+ will be beneficial.
+
+ The IGES community has a suite of tests and conformance utilities to
+ gauge the conformance to specifications and software authors are
+ encouraged to seek those out from NIST [14].
+
+
+
+Nelson, et. al. Standards Track [Page 4]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+4. Encoding and Transport
+
+ a. Unrecognized subtypes of model should at a minimum be treated
+ as "application/octet-stream". Implementations may optionally
+ elect to pass subtypes of model that they do not specifically
+ recognize to a robust general-purpose model viewing
+ application, if such an application is available.
+
+ b. Different subtypes of model may be encoded as textual
+ representations or as binary data. Unless noted in the
+ subtype registration, subtypes of model should be assumed to
+ contain binary data, implying a content encoding of base64 for
+ email and binary transfer for ftp and http.
+
+ c. The formal syntax for the subtypes of the model primary type
+ should look like this:
+
+ Media type name: model
+ Media subtype name: xxxxxxxx
+ Required parameters: none
+ Optional parameters: dimensionality, state
+ (see below)
+ Encoding considerations: base64 encoding is recommended when
+ transmitting model/* documents through
+ MIME electronic mail.
+ Security considerations: see section 5 below
+ Published specification: This document.
+ See Appendix B for references to some of
+ the expected subtypes.
+ Person and email address to contact for further information:
+ Scott D. Nelson <nelson18@llnl.gov>
+ 7000 East Ave.
+ Lawrence Livermore National Laboratory
+ Livermore, CA 94550
+
+ The optional parameters consist of starting conditions and variable
+ values used as part of the subtypes. A base set is listed here for
+ illustration purposes only and will be covered in detail as part of
+ the respective subtypes:
+
+ dimension := string ; a number indicating the number of dimensions.
+ This is used as a "hint" in selecting
+ applicable viewer programs.
+
+
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 5]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ state := string ; "static" or "dynamic". In "static", the
+ observer may move about, thus effecting
+ translations, rotations, pans, zooms, etc.
+ but the data does not change. In "dynamic",
+ the data itself is manipulated via
+ skews, elongations, scales, etc. Note that
+ time evolution is still a static operation
+ since it is just a translation along one of
+ the principal dimensions while the elongation
+ of a cube or object deformation are dynamic
+ operations.
+
+ Note that this optional parameter list does not limit those
+ specified by the various subtypes.
+
+ d. The specific issues relating to the various subtypes are covered
+ as part of the description of those specific subtypes. The
+ following is an example of a typical MIME header used for mail
+ transport purposes:
+
+ To: you@some.org
+ From: nelson18@llnl.gov
+ Date: Fri, 30 Aug 96 13:33:19 -0700
+ Content-Type: model/mesh; dimension="4"; state="static"
+ Content-Transfer-Encoding: base64
+ MIME-Version: 1.0
+ Subject: model data file
+
+ I1ZSTUwgVjEuMCBhc2NpaQojIFRoaXMgZmlsZSB3YXMgIGdlbmVyY...
+ byBDb21tdW5pY2F0aW9ucwojIGh0dHA6Ly93d3cuY2hhY28uY29tC...
+ IyB1c2VkIGluIHJvb20gMTkyICh0ZXN0IHJvb20pCiAgIAojIFRvc...
+ .
+ .
+ .
+
+5. Security Considerations Section
+
+ Note that the data files are "read-only" and do not contain file
+ system modifiers or batch/macro commands. The transported data is
+ not self-modifying but may contain interrelationships. The data
+ files may however contain a "default view" which is added by the
+ author at file creation time. This "default view" may manipulate
+ viewer variables, default look angle, lighting, visualization
+ options, etc. This visualization may also involve the computation of
+ variables or values for display based on the given raw data. For
+ motorized equipment, this may change the position from the hardware's
+ rest state to the object's starting orientation.
+
+
+
+
+Nelson, et. al. Standards Track [Page 6]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ The internal structure of the data files may direct agents to access
+ additional data from the network (i.e. inclusions); the security
+ limits of whom are not pre-supposed. Actions based on these
+ inclusions are left to the security definitions of the inclusions.
+ Further comments about the security considerations for the subtypes
+ will be contained in each subtype's registration.
+
+6. Authors' Addresses
+
+ S. D. Nelson
+ Lawrence Livermore National Laboratory,
+ 7000 East Ave., L-153,
+ Livermore CA 94550, USA.
+ E-Mail: nelson18@llnl.gov
+
+ C. Parks
+ National Institute of Standards & Technology
+ Bldg 220, Room B-344
+ Gaithersburg, MD 20899, USA.
+ E-Mail: parks@eeel.nist.gov
+
+ Mitra
+ WorldMaker
+ 1056 Noe
+ San Francisco, CA 94114
+ E-Mail: mitra@earth.path.net
+
+7. Expected subtypes
+
+ Table 1 lists some of the expected model sub-type names. Suggested 3
+ letter extensions are also provided for DOS compatibility but their
+ need is hopefully diminished by the use of more robust operating
+ systems on PC platforms. The "silo" extension is provided for
+ backwards compatibility. Mesh has an extensive list of hints since
+ the present variability is so great. In the future, the need for
+ these hints will diminish since the files are self describing. This
+ document is not registering these subtypes. They will be handled
+ under separate documents.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 7]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+Table 1.
+
+ Primary/sub-type Suggested extension(s) Reference
+
+ model/iges igs,iges [8]
+ model/vrml wrl [9]
+ model/mesh msh, mesh, silo [10]
+
+ It is expected that model/mesh will also make use of a number of
+ parameters which will help the end user determine the data type
+ without examine the data. However, note that mesh files are self-
+ describing.
+
+ regular+static, unstructed+static, unstructured+dynamic,
+ conformal+static, conformal+dynamic, isoparametric+static,
+ isoparametric+dynamic
+
+ The sub-types listed above are some of the anticipated types that are
+ already in use. Notice that the IGES type is already registered as
+ "application/iges" and that RFC states that a more appropriate type
+ is desired. Note that the author of "application/iges" is one of the
+ authors of this "model" submission and application/iges will be re-
+ registered as model/iges at the appropriate time.
+
+ The VRML type is gaining wide acceptance and has numerous parallel
+ development efforts for different platforms. These efforts are
+ fueled by the release of the QvLib library for reading VRML files;
+ without which the VRML effort would be less further along. This has
+ allowed for a consistent data type and has by defacto established a
+ set of standards. Further VRML efforts include interfaces to other
+ kinds of hardware (beyond just visual displays) and it is proposed by
+ those involved in the VRML effort to encompass more of the five
+ senses. Unlike other kinds of "reality modeling" schemes, VRML is
+ not proprietary to any one vendor and should experience similar
+ growth as do other open standards.
+
+ The mesh type is an offshoot of existing computational meshing
+ efforts and, like VRML, builds on a freely available library set.
+ Also like VRML, there are other proprietary meshing systems but there
+ are converters which will convert from those closed systems to the
+ mesh type. Meshes in general have an association feature so that the
+ connectivity between nodes is maintained. It should be noted that
+ most modern meshes are derived from CAD solids files.
+
+
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 8]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+8. Appendices
+
+8.1 Appendix A -- extraneous details about expected subtypes
+
+ VRML Data Types
+
+ The 3D modeling and CAD communities use a number of file formats to
+ represent 3D models, these formats are widely used to exchange
+ information, and full, or lossy, converters between the formats exist
+ both independently and integrated into widely used applications. The
+ VRML format is rapidly becoming a standard for the display of 3D
+ information on the WWW.
+
+ Mesh Data Types
+
+ For many decades, finite element and finite difference time domain
+ codes have generated mesh structures which attempt to use the
+ physical geometry of the structures in connection with various
+ physics packages to generate real world simulations of events
+ including electromagnetic wave propagation, fluid dynamics, motor
+ design, etc. The resulting output data is then post processed to
+ examine the results in a variety of forms. This proposed mesh
+ subtype will include both geometry and scalar/vector/tensor results
+ data. An important point to note is that many modern meshes are
+ generated from solids constructed using CAD packages.
+
+ Motivation for mesh grew out of discussions with other communities
+ about their design requirements. Many CAD or scene descriptions are
+ composed of a small number of complex objects while computational
+ meshes are composed of large numbers of simple objects. A 1,000,000
+ element 3D mesh is small. A 100,000,000 element 3D structured mesh
+ is large. Each object can also have an arbitrary amount of
+ associated data and the mesh connectivity information is important in
+ optimizing usage of the mesh. Also, the mesh itself is usually
+ uninteresting but postprocessing packages may act on the underlying
+ data or a computational engine may process the data as input.
+
+ Meshes differ principally from other kinds of scenes in that meshes
+ are composed of a large number of simple objects which may contain
+ arbitrary non-spatial parameters, not all of whom need be visible,
+ and who have an implicit connectivity and neighbor list. This latter
+ point is the key feature of a mesh. It should be noted that most
+ meshes are generated from CAD files however. The mesh type has
+ association functions because the underlying physics was used to
+ calculate the interaction (if you crash a car into a telephone pole,
+ you get a crumpled car and a bent pole). Most interesting
+ computational meshes are 4D with additional multidimensional results
+ components.
+
+
+
+Nelson, et. al. Standards Track [Page 9]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ IGES CAD Data Types
+
+ (The following text, reproduced for reference purposes only, is from
+ "U.S. Product Data Association and IGES/PDES Organization Reference
+ Manual," June 1995; by permission.)
+
+ IGES, the Initial Graphics Exchange Specification, defines a neutral
+ data format that allows for the digital exchange of information among
+ computer-aided design (CAD) systems.
+
+ CAD systems are in use today in increasing numbers for applications
+ in all phases of the design, analysis, and manufacture and testing of
+ products. Since the designer may use one supplier's system while the
+ contractor and subcontractor may use other systems, there is a need
+ to be able to exchange data digitally among all CAD systems.
+
+ The databases of CAD systems from different vendors often represent
+ the same CAD constructs differently. A circular arc on one system may
+ be defined by a center point, its starting point and end point, while
+ on another it is defined by its center, its diameter starting and
+ ending angle. IGES enables the exchange of such data by providing, in
+ the public domain, a neutral definition and format for the exchange
+ of such data.
+
+ Using IGES, the user can exchange product data models in the form of
+ wireframe, surface, or solid representations as well as surface
+ representations. Translators convert a vendor's proprietary internal
+ database format into the neutral IGES format and from the IGES format
+ into another vendor's internal database. The translators, called pre-
+ and post-processors, are usually available from vendors as part of
+ their product lines.
+
+ Applications supported by IGES include traditional engineering
+ drawings as well as models for analysis and/or various manufacturing
+ functions. In addition to the general specification, IGES also
+ includes application protocols in which the standard is interpreted
+ to meet discipline specific requirements.
+
+ IGES technology assumes that a person is available on the receiving
+ end to interpret the meaning of the product model data. For instance,
+ a person is needed to determine how many holes are in the part
+ because the hole itself is not defined. It is represented in IGES by
+ its component geometry and therefore, is indistinguishable from the
+ circular edges of a rod.
+
+ The IGES format has been registered with the Internet Assigned
+ Numbers Authority (IANA) as a Multipurpose Internet Mail Extension
+ (MIME) type "application/iges". The use of the message type/subtype
+
+
+
+Nelson, et. al. Standards Track [Page 10]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ in Internet messages facilitates the uniform recognition of an IGES
+ file for routing to a viewer or translator.
+
+ Version 1.0 of the specification was adopted as an American National
+ Standards (ANS Y14.26M-1981) in November of 1981. Versions 3.0 and
+ 4.0 of the specification have subsequently been approved by ANSI. The
+ current version of IGES 5.2 was approved by ANSI under the new
+ guidelines of the U.S. Product Data Association. Under these
+ guidelines, the IGES/PDES Organization (IPO) became the accredited
+ standards body for product data exchange standards. This latest
+ standard is USPRO/IPO-100-1993.
+
+8.2 Appendix B -- References and Citations
+
+ [1] Freed, N., and N. Borenstein, "Multipurpose Internet Mail
+ Extensions (MIME) Part One: Format of Internet Message Bodies", RFC
+ 2045, Innosoft, First Virtual, November 1996.
+
+ [2] Fitzgerald P., "Molecules-R-Us Interface to the Brookhaven Data
+ Base", Computational Molecular Biology Section, National Institutes
+ of Health, USA; see http://www.nih.gov/htbin/pdb for further details;
+ Peitsch M.C, Wells T.N.C., Stampf D.R., Sussman S. J., "The Swiss-3D
+ Image Collection And PDP-Browser On The Worldwide Web", Trends In
+ Biochemical Sciences, 1995, 20, 82.
+
+ [3] "Proceedings of the First Electronic Computational Chemistry
+ Conference", Eds. Bachrach, S. M., Boyd D. B., Gray S. K, Hase W.,
+ Rzepa H.S, ARInternet: Landover, Nov. 7- Dec. 2, 1994, in press;
+ Bachrach S. M, J. Chem. Inf. Comp. Sci., 1995, in press.
+
+ [4] Richardson D.C., and Richardson J.S., Protein Science, 1992, 1,
+ 3; D. C. Richardson D. C., and Richardson J.S., Trends in Biochem.
+ Sci.,1994, 19, 135.
+
+ [5] Rzepa H. S., Whitaker B. J., and Winter M. J., "Chemical
+ Applications of the World-Wide-Web", J. Chem. Soc., Chem. Commun.,
+ 1994, 1907; Casher O., Chandramohan G., Hargreaves M., Murray-Rust
+ P., Sayle R., Rzepa H.S., and Whitaker B. J., "Hyperactive Molecules
+ and the World-Wide-Web Information System", J. Chem. Soc., Perkin
+ Trans 2, 1995, 7; Baggott J., "Biochemistry On The Web", Chemical &
+ Engineering News, 1995, 73, 36; Schwartz A.T, Bunce D.M, Silberman
+ R.G, Stanitski C.L, Stratton W.J, Zipp A.P, "Chemistry In Context -
+ Weaving The Web", Journal Of Chemical Education, 1994, 71, 1041.
+
+ [6] Rzepa H.S., "WWW94 Chemistry Workshop", Computer Networks and
+ ISDN Systems, 1994, 27, 317 and 328.
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 11]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+ [7] S.D. Nelson, "Email MIME test page", Lawrence Livermore National
+ Laboratory, 1994. See http://www-dsed.llnl.gov/documents/WWWtest.html
+ and http://www-dsed.llnl.gov/documents/tests/email.html
+
+ [8] C. Parks, "Registration of new Media Type application/iges",
+ ftp://ftp.isi.edu/in-notes/iana/assignments/media-types/
+ application/iges, 1995.
+
+ [9] G. Bell, A. Parisi, M. Pesce, "The Virtual Reality Modeling
+ Language",
+ http://sdsc.edu/SDSC/Partners/vrml/Archives/vrml10-3.html, 1995.
+
+ [10] S.D. Nelson, "Registration of new Media Type model/mesh",
+ ftp://ftp.isi.edu/in-notes/iana/assignments/media-types/model/
+ mesh, 1997.
+
+ [11] "SILO User's Guide", Lawrence Livermore National Laboratory,
+ University of California, UCRL-MA-118751, March 7, 1995,
+
+ [12] E. Brugger, "Mesh-TV: a graphical analysis tool", Lawrence
+ Livermore National Laboratory, University of California,
+ UCRL-TB-115079-8, http://www.llnl.gov/liv_comp/meshtv/mesh.html
+
+ [13] S. Brown, "Portable Application Code Toolkit (PACT)", the
+ printed documentation is accessible from the PACT Home Page
+ http://www.llnl.gov/def_sci/pact/pact_homepage.html
+
+ [14] L. Rosenthal, "Initial Graphics Exchange Specification
+ (IGES) Test Service",
+ http://speckle.ncsl.nist.gov/~jacki/igests.htm
+
+8.3 Appendix C -- hardware
+
+ Numerous kinds of hardware already exist which can process some of
+ the expected model data types and are listed here for illustration
+ purposes only:
+
+ stereo glasses, 3D lithography machines, automated manufacturing
+ systems, data gloves (with feedback), milling machines,
+ aromascopes, treadmills.
+
+
+
+
+
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 12]
+
+RFC 2077 Model Primary MIME Types January 1997
+
+
+8.4 Appendix D -- Examples
+
+ This section contains a collection of various pointers to examples of
+ what the model type encompasses:
+
+ Example mesh model objects can be found on this mesh page:
+ http://www-dsed.llnl.gov/documents/tests/mesh.html
+
+ Various IGES compliant test objects:
+ http://www.eeel.nist.gov/iges/specfigures/index.html
+
+ VRML Test Suite:
+ http://www.chaco.com/vrml/test/
+
+ An image of a model of a shipping cage crashing into the ground:
+ http://www.llnl.gov/liv_comp/meiko/apps/dyna3d/cagefig2.gif
+
+ An image of a 100,000,000 zone mesh:
+ http://www.llnl.gov/liv_comp/meiko/apps/hardin/PMESH.gif
+
+ A video of a seismic wave propagation through a computational mesh:
+ http://www.llnl.gov/liv_comp/meiko/apps/larsen/movie.mpg
+
+9. Acknowledgements
+
+ Thanks go to Henry Rzepa (h.rzepa@ic.ac.uk), Peter Murray-Rust
+ (pmr1716@ggr.co.uk), Benjamin Whitaker
+ (B.J.Whitaker@chemistry.leeds.ac.uk), Bill Ross (ross@cgl.ucsf.EDU),
+ and others in the chemical community on which the initial draft of
+ this document is based. That document updated an IETF Internet Draft
+ in which the initial chemical submission was made, incorporated
+ suggestions received during the subsequent discussion period, and
+ indicated scientific support for and uptake of a higher level
+ document incorporating physical sciences[2-7]. This Model submission
+ benefited greatly from the previous groundwork laid, and the
+ continued interest by, those communities.
+
+ The authors would additionally like to thank Keith Moore
+ (moore@cs.utk.edu), lilley (lilley@afs.mcc.ac.uk), Wilson Ross
+ (ross@cgl.ucsf.EDU), hansen (hansen@pegasus.att.com), Alfred Gilman
+ (asg@severn.wash.inmet.com), and Jan Hardenbergh (jch@nell.oki.com)
+ without which this document would not have been possible. Additional
+ thanks go to Mark Crispin (MRC@CAC.Washington.EDU) for his comments
+ on the previous version and Cynthia Clark (cclark@ietf.org) for
+ editing the submitted versions.
+
+
+
+
+
+
+Nelson, et. al. Standards Track [Page 13]
+