Abstraction layers

A vanilla development from scratch is typically treated in two to five layers of abstraction 7 bigger projects have more abstraction layers, each one separately maintained. Typical layers are as follows. 

Abstract Layered double hydroxides (LDHs) comprise au extensive class of materials that are very easy to synthesize in the laboratory, albeit not always as pure phases. In this chapter, we review the wide variety of methods that are available for the synthesis of LDHs and focus on the way in which the physicochemical properties of the materials (such as phase piuity, crystallinity and surface area) vary with synthesis method. The flexibility of the different methods is also discussed some methods can be used to synthesize LDHs containing a wide range of constituent cations and anions, whilst others are more limited in scope. In some cases, the potential for scale-up of a method to produce larger quantities of material is also noted. 

These abstraction layers offer tremendous benefits to the software development process with reduced development complexity and costs and increased productivity. Application server platforms and blueprints also provide software development frameworks to help the software fit into specific architecture patterns. One of the most commonly adopted software architecture patterns for enterprise systems is the layered architecture (Buschmann et al., 1996 Fowler, 2003a). It is also the heart of the J2EE blueprint (Alur et al., 2003). 

In order to describe the levels of universality and specificity of chemical features, a simple layer model is proposed to allow referral to these properties more easily. Table 6.1 shows a proposed classification of abstraction layers of chemical features A lower level corresponds to higher specificity and therefore lower universality. 

Table 6.1 Abstraction layers of chemical feature constraints...

Table 3.1 Abstraction layers of pharmacophoric feature contraints.

System files Besides the previously listed files, all of which are located in the root of the C partition on the computer, Windows 2000 also needs a number of files from its system directories, including the hardware abstraction layer (HAL.DLL) and the Windows 2000 command file (WIN.COM). 

NTLDR then loads the kernel file (NTOSKRNL. EXE), hardware abstraction layer (HAL), and the Registry, as well as any device drivers found there. 

On the other hand, four abstraction layers have been considered to model communication processes. First, the description layer gives information about given input or output functionality, and if the data are persistent. On the next abstraction layer, data sources and sinks are combined to transmission channels, characterized by the media coding used. In general, an application will use several channels, e.g. one for audio and one for video transmissions. To integrate these channels into a communication process, contexts between channels are created on the third layer. So far, the whole specification is independent from communicating applications located on the users hosts. 

Functional Analysis A functional analysis is usually conducted in the beginning of the concept generation. This analysis works as the interface between requirements and their realization. It used to focus only on the part of requirements expressing what the final product should do. The concept of function is often represented as a black box containing a verb of action, inputs, and outputs. Such analysis consists of an abstraction layer... 

Fig. 5 Generic modular stmcture of the overall inteimoleculai opdmizadon toolbox consisting of the abstract layer Generic Optimization and the three specific layers Frace-Field (EF) Parameterization, Parallel Jobs (PJOBS), and Simulation. Most of the modules require input parameters, which are defined in the configuration file (i.e., Config )...

Virtualization of supply chain systems involves both IT and organizational changes Liu et al. (2008). In the VSC, hierarchical virtualization of a network provides a flexible, granular, protection resource. Using the Hardware Abstract Layer (HAL) concept, network services are handled by a number of virtual servers (Dawson 2008). In the event that a physical server hosting the virtual servers fails, another physical server already operating on the network with the virtual systems can stand in as an alternative physical host. 

Also for basic software or in AutoSar abstraction levels are addressed but in this case we don t mean horizontal abstraction levels but functional (perspectival) abstraction levels (e.g. hardware abstraction or microcontroller abstraction layer (MCAL)). Nevertheless, the interface between application software and microcontroller still play an important role in the definition of the abstraction level. In early revisions of ISO 26262 the hardware software interface (HSl) was implemented in part 5 (Product development at the hardware level) and 6 (Product development at the software level) and only after the CD version of ISO 26262 it moved into part 4 (Product development at the system level). What is special about this is that the microcontroller as a hardware element, similar to the electronics housing, predetermines essential design characteristics for the software. In order for these two components to interact properly, those characteristics and their potential flaws as well as the functions and their potential failure functions need to be considered. This obviously goes for all component interfaces. In the case of HSl we find a lot of relevant interface parameters. This means, that it is not only about the correct functions of the so-called low-level drivers, which provide information on microcontrollers to the software, the operating system, peripheral (DMA, I/O, bus etc.), internal communication, logic unit, memory or function libraries, which are provided by the computer, but also the systematic protection of potential failure or malftmction at this interface. 

Interfaces of elements are always given by the nature of electronic systems. Those interfaces must be specified in order to assure, that systems could realize the intended functions. A mere software component only exists because it is defined like that. The low level driver (e.g. MCAL microcontroller abstraction layer), which read the information from the microcontroller hardware and provide the data interface to further software components, these software elements built the hardware-software-interface (HSI). Mere electronic parts could not be considered without their interfaces to mechanical elements, such as PCB, connectors etc. This means, no matter at what horizontal abstraction level electronic are considered, there will always be mechanical intersections. Even the bonding (connection between the silicon and the pin) in a microcontroller or ASIC primarily depends on the production process, which creates the mechanical connection. The example of the hardware software interface shows how deep we have to go into the details of the components in order to ensure sufficient coverage and sufficient unique level of specification. 

In order to comply with the Autosar standard, the all data for the RTE (Real-time-environment) need as qualifier at the virtual function bus for any signal a safety qualifier or a diagnostic key. Typical to the Autosar the hardware (HAL) and microcontroller (MCAL) abstraction layer could be considered. An additional system- or sensor abstraction layer could be introduced, so that the application software already gets physical data according to the functional system design, so that the input data and the functions in the application become traceable and more... 

For the application software it is sufficient to define the data formats for the application software. The hardware-software-interface (HSI) allocated to the basic software. Therefore, the software architecture analysis is limited to possible systematic failures, which are only reduced to the possible systematic failure of the application software. If in a sufficiently independent horizontal abstraction layer... 

Variables can be grouped into a dataset. The goal of the dataset is to group data related to one simulation task and to simplify the handling of values. It is also very important to make data accessible and usable for nonexperts. For each dataset more profiles can be assigned. Each profile represents a particular combination of physical data sources but it must contain exactly the same group of variables as defined in the related dataset. Datasets and profiles create an abstract layer which is built on top of a physical layer. The overview of the data architecture is illustrated in Rg. 10.5. 

The architecture of simulations is very similar to the data architecture described in the previous section. As defined in Sect. 10.3, a simulation module can be seen as a black box with an interface. It is an abstract layer in the architecture. The physical layer contains information about implementations of simulation tools interfaces and various configurations. 

In order to define a complex simulation tasks, the abstract layer of the simulation module must be defined in a very general form. Because this work is focused on the simulations of processes or mechatronic systems, a description of continuous-time finite dimensional dynamical systems (Antsaklis and Michel 2006) has been chosen as a basis of simulation module interface. It can be simplified and used also for a description of more simple systems. All datasets related to a simulation module can be considered as 6-tuple ... 

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