First, a more precise comparison is needed, because Larch is not a single language, but a family of languages (see above). Another problem with this comparison is that Larch has two tiers, but VDM-SL [Jones90] [ISO-VDM96] [Fitzgerald-Larsen98], Z [Hayes93] [Spivey92], and COLD-K [Feijs-Jonkers92] are all integrated languages, which mix aspects of both of the tiers of the Larch family.

Larch [Guttag-Horning93] may be thought of as an approach to formal specification of program modules. This approach is an extension of Hoare's ideas for program specification [Hoare69] [Hoare72a]. Its distinguishing feature is that it uses two "tiers" (or layers) [Wing83]. The top tier is a behavioral interface specification language (BISL), tailored to a specific programming language. Such BISLs typically use pre- and postcondition specifications to specify software modules.

Like VDM-SL, Z [Hayes93] [Spivey92] (pronounced "zed") is a specification language that allows both the specification of mathematical values and program modules. Like LSL, Z allows the definition of mathematical operators equationally (see [Spivey92], section 3.2.2). A Z schema is roughly comparable to an LSL trait. The main difference between Z and LSL is that in Z specifications can include state variables.

A good place to start is the Guttag and Horning's book [Guttag-Horning93]. (This book is sometimes called "the silver book" by Larchers.) Consider it required reading. If you find that all tough going, you might want to start with Liskov and Guttag's book [Liskov-Guttag86], which explains the background and motivates the ideas behind abstraction and specification. (See section 1.9 What is the use of formal specification and formal methods?, for more background.

By VDM, one means, of course, the specification language VDM-SL [Jones90] [ISO-VDM96] [Fitzgerald-Larsen98]. In comparison with LSL, in VDM-SL one can specify mathematical values (models) using constructs similar to those in denotational semantics and typed, functional programming languages.

Like Larch, COLD-K [Feijs-Jonkers92] makes more of a separation into mathematical and interface specifications, although all are part of the same language. The part of COLD-K comparable to LSL is its algebraic specifications (see [Feijs-Jonkers92], Chapters 2 and 3). In contrast to LSL, COLD-K does not use classical logic, and can specify partial functions. All COLD-K types have an "undefined" element, except the type of the Booleans.

The two "tiers" used in the Larch family of specification languages are LSL, which is called the bottom tier, and a behavioral interface specification language (a BISL), which is called the top tier. This specification of program modules using two "tiers" is a deliberate design decision (see [Wing83] and [Guttag-Horning93], Chapter 3).

The language is actually very simple, and resembles Smalltalk, or even Simula. Due to the constraints of visual programming, the syntax needs to as simple as possible, to reduce the amount of visual clutter and input required by the user. Thus Visula is dynamically typed - types of variables do not need to be declared, rather they depend on the value actually assigned. Visula has no concept of global scope (except for the special std object), all classes in Visula are nested.

According to Jim Horning (personal communication, January 20, 1998) and John Guttag (personal communication, March 28 1998): "The name was not selected at PARC (hence from the Sunset Western Garden Book), but at MIT. The project had been known informally there as 'Bicycle'." One day Mike Dertouzos [director of the MIT Laboratory for Computer Science] and John were talking on the phone.

The main difference between LSL and a Larch BISL is that in LSL one specifies mathematical theories of the operators that are used in the pre- and postcondition specifications of a Larch BISL. Thus LSL is used to specify mathematical models and auxiliary functions, and the a Larch BISL is used to specify program modules that are to be implemented in some particular programming language.

The following is adapted from a posting of Horning to the larch-interest mailing list on June 19, 1995, which was itself condensed from the preface of [Guttag-Horning93].) This project has been a long time in the growing. The seed was planted by Steve Zilles on October 3, 1973.

This question might mean one of several other more precise questions. These questions are discussed below. One question is: is there a Larch-style BISL for some particular object-oriented (OO) programming language? Yes, there are Larch-style BISLs for Modula-3 (see [Guttag-Horning93], chapter 6, and [Jones91]), Smalltalk-80 (see [Cheon-Leavens94]), and C++ (see [Leavens97] [Leavens96b]).

The Larch Shared Language (LSL) (see [Guttag-Horning93], Chapter 4, and [Guttag-Horning-Modet90]) is a language for specifying mathematical theories. LSL is a kind of equational algebraic specification language [Guttag75] [Guttag-Horning78] [Goguen-Thatcher-Wagner78] [Ehrig-Mahr85] [Futatsugi-etal85] [Mosses96] [Loeckx-Ehrich-Wolf96]. That is, specifications in LSL mainly consist of first-order equations between terms.

The Larch Prover (LP) [Garland-Guttag95] is a program that helps check and debug proofs. It is not geared toward proving conjectures automatically, but rather toward automating the tedious parts of proofs. It automates equational rewriting (proofs by normalization), but does not (by default) automatically try other proof techniques. aid the debugging of specifications (i.e.

The SSE specification published here is a draft specification. We are seeking feedback on how this draft SSE extension to RSS and Atom can be improved. We expect to produce the 1.0 revision of the spec in the near future. To discuss the SSE spec or for questions, please send mail to the FEED-TECH list on http://discussms.hosting.lsoft.com/scripts/wa-MSD.exe?INDEX.

CellML provides a very powerful and general way of describing most classes of cellular model. Its focus is on a component-based architecture (facilitating easy re-use of models and parts of models) and the mathematical description of models. A CellML document defines the minimum amount of information needed to properly archive models and to run simulations, leaving a lot of work for processing software in terms of rendering, and simulation configuration.

AMPL is one of several optimization modeling systems that are designed around specialized algebraic modeling languages. These languages employ adaptations of familiar mathematical notation to describe optimization problems as subject to constraints expressed as equalities or inequalities between algebraic expressions in the decision variables. Advanced interpreters and interfaces for these languages provide support for simplifying and analyzing models.

Many scripting languages are in use today, and comparing scsh with all of them would be impossible. Here, we therefore restrict ourselves to the following three popular scripting languages: Perl, Python and Ruby. Below, they will be collectively referred to as PP&R.

Little b and XML-based languages, like SBML, are complementary solutions to the problem of model building and sharing. SBML is (and must be) developed through a process of consensus amongst the community. This is an important activity, which has the benefits and disadvantages that come with getting a group of people to come to agreement. Also, XML is language-neutral which makes it a good choice for transferring data between programs written in different languages.

The Single UNIX Specification specifies application programming interfaces (APIs) at the source level, and is about application source code portability. Its neither a code implementation nor an operating system, but a stable definition of a programming interface that those systems supporting the specification guarantee to provide to the application programmer.

PSL's primary role is not envisioned to be a process modeling language, see question 4. It can be used as an interchange language which would allow manufacturing applications to exchange discrete process data. For example, an IDEF3-based application could use PSL to exchange process models with a Petri net-based application, in the same way that STEP can be used to exchange product models among CAD systems. It can also be used to define the meaning of languages like IDEF3 and Petri Nets.

Most forms of treatment including acupuncture, massage, ultrasound, medication, TENS, etc. have been used to treat pain and stimulate the healing processes. For the most part the effects of these treatments have been discouraging or provide only temporary relief as they do little more then mask the symptoms. Alleviating symptoms has generally and unfortunately become the accepted norm of treating most conditions.

The NPL and MozPL both attempt to strike a middle ground between promoting free source development by commercial enterprises and protecting free source developers. Like the GPL, they require that any and all changes to code covered by the license must be made publicly available. However, they also allow you to combine covered code with other code to create a larger work without requiring that other code to be covered by the license. This is similar to, but even less restrictive, than the LGPL.

The real claim to fame for the IFPA: PRACTICAL. The IFPA did not build our programs to win acclaim from academicians in the Ivory Towers of Academia; we dont care about their opinion. The IFPA did not build our programs to win acclaim from doctors in the medical community we dont care about their opinion. The IFPA did not build our programs to win envy from the other certifications available today we dont care about their opinion.

Unlike some other hair loss treatment products available on the market today, Retane is clinically proven to stop male and female hair loss. It is fast acting - most men and women will experience a significant reduction in hair loss within 4 weeks. Retane is an all natural hair tonic that stops hair loss. It does not contain chemical drugs.

The LifePak Challenge has been created to help our Distributors and customers compare LifePak to competitors. Click here to view the LifePak Challenge.

It is quite difficult to answer this question in an objective manner. The first challenge is bringing the film image to the PC so that the both digital and film images can be compared side by side. this introduces several variables: The choice of scanning hardware, and the parameters of the scanning software. The next challenge is that digital and film images fall apart in different ways at the limits.

SpinRite and ScanDisk are entirely different types of products. ScanDisk replaces the original DOS CHKDSK command, which verified the logical file system structure of the hard drive (the newer CHKDSK command no longer performs that function). Microsoft created ScanDisk because people were switching off their computers without first exiting Windows. This resulted in corruption of the file system.

the infrastructure level, the Handle System allows individual namespaces to be registered and later discovered by any application over the Internet. Namespaces registered under the Handle System are unique, and queries will always be directed to the responsible handle server for resolution. An LDAP server typically runs in isolation, with service referrals from one namespace to another performed at the peer level when available.

This site is translated into several languages, and we are adding new languages all the time. If you can translate from English into a language that you are an expert at, we invite you to participate! It's a good way to get involved in the CouchSurfing.com community.