Architectural elements

User-defined models, such as design patterns, frameworks, and other architectural elements, are also defined in their own packages. The set of definitions composing each model is grouped into a package and can be used by many others. Even attribute definitions, associations, and refinement relations are defined within a package. 

The rules or guidelines that determine where and how these architectural elements are apphed, such as For any composite user-interface panel that may be reused, make all internal events available via the composite. In the extreme case, these rales can be formalized to fully define a translation scheme. 

The design of any system embodies several partial designs of how the pieces collaborate. These designs constitute some of the key architectural elements used in the system design. The resulting design is a composition of these partial collaborations, unified via objects that participate in more than one collaboration. The architecture is often best described and understood in terms of recurring patterns of such collaborations. 

Let s begin on a small scale the architecture of cells. The cells of plants and bacteria have strong cell walls that provide for maintenance of shape and protection against ontside forces. The cells of animals, including those of the human body, in contrast, lack cell walls. Animal cells make do with a fragile cell membrane. Our cells, consequently, have need of an internal architecture to meet the needs supplied by cell walls in other life forms. Cells have three types of internal architectural elements microtubules, intermediate filaments, and actin filaments. Each of these structures is composed of protein. 

Crasser, K.D. (1998) HMGl and HU proteins architectural elements in plant chromatin. Trends Plant Sci. 3, 260-265. 

Crothers, D.M. (1993) Architectural elements in nucleoprotein structures. Curr. Biol. 3, 675-676. Stros, M. (2001) Two mutations of basic residues within the N-terminus of HMG-1 B domain with different effects on DNA supercoiling and binding to bent DNA. Biochemistry 40, 4769-4779. 

HMGN proteins are small, ubiquitous, chromatin architectural elements that bind to the 147 bp nucleosome core via their highly conserved nucleosome binding domain. They bind as homodimers, interacting near base 25 of the nucleosome DNA, and near the dyad axis. When incorporated into minichromosomes, HMGN proteins decrease chromatin folding in a manner that is dependent on their C-terminal domain, with a concomitant increase in transcription. 

The fact that the visual imagery of my dream is synthetic and bizarre could itself be isomorphic to the autoactivation of the visual brain—to the near simultaneous activation of visual networks encoding general barn features, features of my particular barn, and the local architectural elements, cement and stone, that I was playing with on my walk last night. 

Segall, A. M., Goodman, S. D. Nash, H. (1994). Architectural elements in nucleoprotein complexes interchangeabiUty of specific and non-specific DNA binding proteins. EMBO J. 13, 4536-4548. 

Many questions pertaining to membrane processes in general and ligand/membrane receptor interactions in particular can be addressed by a novel model membrane system, i.e., polymer-supported or polymer-tethered lipid bilayers [12,14], The basic structural unit for this sensor platform is the tethered lipid bilayer membrane [16] displayed in Fig. 2D. The essential architectural elements of this supramolecular assembly include the solid support, e.g., an optical or electrical transducer (device), the polymeric tether system which provides the partial covalent and, hence, very stable attachment of the whole membrane to the substrate surface, and the fluid lipid bilayer, functionalized if needed by embedded proteins. 

Figure 14 Glazed terracotta, an architectural element from a 16th century building in Northern Germany...

Whereas ceramics are polycrystalline materials, consisting of several phases (discrete chemical compounds), glass consists of a three-dimensional network with short-range order. For both, deterioration can occur early due to daily use or much later during exposure in museums, or due to aggressive soil environments for archaeological objects or due to weathering of architectural elements. 

Airlock Entry - A building architectural element (vestibule) with two airtight doors that reduces the amount of air infiltration and exfiltration when the exterior most door is opened. 

An architectural element for shading windows and wall surfaces placed on the exterior of a building can be fixed or movable. 

Galvanized reinforcement offers significant advantages compared to carbon steel under equivalent circumstances. These include an increase of initiation time of corrosion a greater tolerance for low cover, e. g. in slender (architectural) elements, and corrosion protection is offered to the reinforcement prior to it being embedded in concrete. 

One of the most remarkable properties of self-assembly is its ability to generate exceedingly coinplica ted supramolecular structures from fairly simple components. Perhaps the most elegant embodiment of this phenomenon is protein stmcture. Proteins exhibit at least four hierarchies of stmcture primary, secondary, tertiary, and quaternary stmctures. Primary stmcture describes the covalent connections making up the sequence of amino acids in each strand. Secondary stmcture involves local architectural elements created when portions of a strand... 

Although the Myers and Danishefsky groups were the first to complete total syntheses of dynemicin A (1), the core architecture of the entire natural product had, in fact, been completed several months earher by Professor Stuart L. Schreiber and his group at Yale University (now at Harvard University). All that separated the advanced stracture synthesized by these researchers (107, Scheme 16) from the final target were three phenolic methyl ethers, which, unfortunately, proved resilient to cleavage. As such, the developed route cannot constitute a total synthesis in the strict sense of the definition. However, based on our discussion above, the accomplishment of even this advanced compound is certainly laudable, and, for this reason, this work is included here because it provides an alternative and especially creative solution for the construction of the key architectural elements of dynemicin A. 

Fortunately, this issue, along with all the other challenges discussed above, was successfully addressed in 1998 and 1999 with the first chemical synthesis of vancomycin (1) by the Nicolaou group at The Scripps Research Institute,and its aglycon (13, see column figure) by David Evans and his co-workers at Harvard University. For the remainder of this chapter, we will analyze these unique and insightful solutions in detail, each of which required the investment of several years in basic research to develop the special synthetic strategies and tactics that were ultimately called upon to tackle the most nefarious architectural elements of vancomycin. 

Verifiable Results of a combination of analysis techniques and reviews/ inspections, including structured design walkthroughs and inspections against the design notation standard verifiability criteria formal method proofs that show determinism verification results of the architectural element (note some developers and certification authorities adopt the approach that if the architectural element was verified, this implies it is verifiable) - the limitation with this approach is that the inference is made via an assumption about the extensiveness of verification (and is implicit), rather than specific evidence in this regard. 

The strucmral view of the system must then be completed by the expression of the system behaviour. During the previous phases of the SE method, the functional behaviour has been described. The first task to perform is to translate this behaviour in the AltaRica DF model. For this phase, we assume that the behaviour has been allocated to the architecmre. We can thus add a rule to depict a functional modelling approach well-suited to prepare risk and reliability analysis, which is the allocation of the behaviour to precise architectural elements. We can notice that those allocation steps are clearly parts of the OOSEM, where logical nodes are allocated to physical nodes . The behaviour of AltaRica DF nodes is written in assertions and transitions as presented in section 4. The task of behaviour modelling consists in identifying the SysML elements that reflect the events, affectations and guards that constitute the assertions and transitions. 

Architecture Design The architecture can follow some RFID reference model and must be extensible so that new architectural elements or scenarios can be added in the next milestones. 

Let me start with a few words about a very special architectural element in chemistry, called chirality. When we look at the mirror, do we really see ourselves The answer to the question is no To understand the reason, look at the cute snail and her mirror image in Figure 1.8a. They are clearly not identical. For example, the spiral on the snail s shell is counterclockwise, while on the shell of her mirror image the spiral is clockwise. You cannot possibly match a clockwise spiral with a counterclockwise... 

The drawings on the hottom show architectural elements that appear in proteins. The drawing on the left-hand side shows that protein chains can assume a helical shape, called an a-helix (as shown in purple), or a sheet shape, called a p-sheet (as shown in green). The drawing on the right shows two protein parts that maintain NH 0 contacts, which is the architecture that appears in silk. 

The architecture of this molecule is governed by the N—H 0=C and N—H N H-bonds between base pairs, and by the architectural element of these H-bonds, the 180° N—H 0(N) angles. As shown in Figure 7.16, it turns out that bases of one strand pair up only with specific bases in the second strand. (Figure 7.16 gives the full names of the bases.)... 

A comprehensive design representation, with the aid of a graphical engine, of the architectural elements of a program and their interdependencies... 

This chapter is intended to provide insight into the design needs of embedded systems and the formalisms available to address those needs we discuss them in section 2 and 3 respectively. We will explain the suitability of AADL and will present its architectural elements for modelling embedded systems in section 4. We will also highlight the shortcomings currently present in AADL and describe its extension mechanism by addressing one of the shortcomings with the help of an example, in section 5. 

AADL consists of a rich set of architectural elements for modelling components, their interactions and their configurations. Architectural elements and the core concepts of the language are given in figure 1. 

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