The physical aspect of computers telecommunications and other devices

2.1 GTS Infrastructure

The physical components of a ground transportation system are MOs, static objects, and (in most cases) the road network itself (see Fig. 1) [8,9]. MOs are objects capable of movement. They are often referred to as either mobile hosts [10,11] or mobile clients [3,12]. MOs move on a fixed network bound by velocity constraints. Both a person carrying a cellular phone and a vehicle moving on the road are tangible examples of MOs. MOs are usually equipped with some type of location-determining device such as a GPS device to sense and measure the speed and position of an MO. SOs are objects with stationary locations such as buildings.

2 Thermodynamics and reaction kinetics

The pure component physical properties are available in the Aspen databanks. The UNIQUAC model is selected to model the phase equilibria, using two sets of binary interaction parameters. One set calculates the VLE, while the other calculates the LLE. The parameters for water/AA and water/i-BuOH are available in Aspen, for both VLE and LLE applications; for water/i-BA, the parameters are estimated with UNIFAC-LL group contribution method, while for the remaining three pairs i-BuOH/i-BA, i-BuOH/AA and i-BA/AA, the UNIFAC method is used.

Equation (1) represents the liquid phase esterification reaction of AA and i-BuOH with formation of i-BA and water. The course of reaction under catalytic conditions (Amberlyst 131) can be described by the LHHW kinetic model given by equations (2)-(5), taken from recent literature (Karakus et al., 2014). The parameters for the adsorption constant equation are regressed using the data presented in the same reference. These are shown in Table 1.

Table 1. Regression parameters A and B of the adsorption constant equation

(1)AA+i‐BuOH⇄Amberlyst131i‐BA+Water

(2) r=kfKacidKalcoholaacidaalcohol‐1/Keqaesterawater1+Kacidaacid+Kalcoholaalcohol+K esteraester+Kwaterawater2

(3)kf /kmol/kgcat⋅s=2.526⋅108 exp−76015.78.314T

(4)Keq=exp1972.6 /T−1.5134

(5)lnKi=Ai+Bi/T ,i=acid,alcohol,water,ester

Figure 1 shows the x-y diagrams for key binary systems; i-BuOH/i-BA diagram (left) suggests a good separation of the acrylate from a mixture with alcohol at atmospheric pressure, while the AA/i-BA diagram (right) shows that the acrylate separation from a mixture with acid is favoured at vacuum conditions. Figure 2 shows ternary diagrams of the four component system. For the three systems in which water is present, large immiscibility areas are observed. Water and acid are fully miscible; the ternary system of the organic components presents no immiscibility area. The binary systems water/i-BuOH and water/i-BH, and the ternary water/i-BuOH/i-BA present minimum boiling heterogeneous azeotropy.

2 Thermodynamics and reaction kinetics

The pure component physical properties of all four components describing the system are available in the Aspen databanks. The UNIQUAC-HOC method is selected to model the phase equilibria, using one set of binary interaction parameters. The parameters for water/AA, water/2-EH and AA/2-EH are available in Aspen, while for the remaining three pairs are estimated using the UNIFAC-LL group contribution method. Neither parameters nor phase equilibrium data were found in literature to describe the systems containing 2-EHA. Figure 1 shows the ternary diagrams in which water is presents. All three systems have large immiscibility areas. The AA and water are completely miscible, and the same holds for the ternary system comprised from the organic components only. Another observation is that the binary systems water/2-EHA and water/2-EH presents minimum boiling heterogeneous azeotropy.

Equation (1) represents the liquid phase esterification reaction of AA and 2-EH with formation of 2-EHA and water. The course of reaction under catalytic conditions (Amberlyst 70) can be described by the pseudo-homogeneous kinetic model given by equation (2), recently described in literature (Komon et al., 2013).

(1)AA+2‐EH⇄Amberlyst702‐EHA+Water

(2)r=k0exp−EA/RTaAAa2−EH−1/Keqa2−EHAaWater

(3)ln1/Keq=A+B/T

Komon et al. (2013) calculated the activities using the UNIFAC model, while in the present study, the UNIQUAC-HOC model is employed. Thus, for consistency reasons, we regress again the kinetic parameters k0 [kmol/(kgcat · s)], EA [kJ/mol], and the two constants, A [-] and B [K], of the invers of the equilibrium constant equation (3); the experimental data and all details regarding the experiments as reported in the same reference are used. Aspen Batch Modeler is used to make the regression. Conveniently, and for maintaining consistency, a property file is generated using Aspen Plus and imported. 24 sets of experimental data are used in this regression (AA:2-EH mole ratio of 1:7, 1:5, 1:3 each at 90, 100, 110, 120°C; and 3:1, 5:1, 7:1 each at 80, 90, 100, 110°C). A typical entry requires the initial reaction conditions and the mole fraction of 2-EHA in time. Figure 2 shows the comparison between experimental and calculated molar fraction of 2-EHA at different temperatures and selected molar ratios of AA:2-EH. A good agreement is observed. The regressed values are: k0 = 722.7 kmol/(kgcat · s), EA = 51.77 kJ/mol, A = -8.5845, and B = 2438.5 K.

17.2.9 Head-Disk Assembly

All the foregoing physical components described in this section are assembled together to form a head-disk assembly (HDA). It basically includes all the major components of a disk drive except for most of the electronics. The only electronics that is part of the HDA is the small AEM which is integrated with the flex cable. As discussed previously, the size of a dust particle is thousands of times greater than the head's flying height. With the surface of the disk traveling at over 100 mph past the head, a collision of the head with any contaminant can result in damage to either the head or the recording media. Therefore, assembling the HDA is done inside a clean room. The HDA is mounted inside a housing which is then sealed to keep contaminants out. However, the compartment is not airtight. Rather, air exchange with the outside is allowed through a breather filter so that the drive can adjust to the outside air pressure.8 To capture any contaminants that may come off the HDA after the drive leaves the assembly line, a recirculation filter can also be found inside the HDA compartment.

Physical

Power sources and other physical components of the systems should provide some level of built-in redundancy in the device; in some cases, spare parts will be stockpiled to provide quick replacement of failed components. For systems that can suffer short periods of downtime, it may be sufficient to keep spare hardware available and establish a quick imaging and rebuilding process. At a macro level, site redundancy, disaster recovery plans, and business continuity plans should all be in line with the value of the resource to the organization. Many factors go into this planning that is beyond the scope of this architecture.

Comprehend

Site analysis has two components: physical environmental analysis and RF environmental analysis.

Interference can have adverse effects on the following characteristics of an RFID system: read speed, accuracy of communication, and read range.

To capture the RF signal, an antenna can be placed in the middle of the interrogation zone and connected to the input of the spectrum analyzer.

You use blueprints to visualize the site infrastructure and then to enter some results of the site analysis. Therefore, the blueprint can be used before during and after site analysis.

FFCA is performed to identify the sources of interference, to determine the interrogation zone locations, whereas PLCM is performed to get an insight into the details of a given interrogation zone so that it can be fine-tuned and configured for optimal performance.

2.8 Hardware-Firmware-Software Interaction

Hardware refers to the physical components of a system, such as the memory, hard disk drive, graphic card, sound card, central processing unit, motherboard, monitor, adapter card, and ethernet cable. Software refers to the instructions or the programs running on hardware, which direct a computer to perform specific tasks or operations, in contrast to hardware upon which the system is built. Computer software is the information processed by systems, for example, data, programs, and libraries. For example, software could be operating systems (OS). OS provides overall control for hardware system and applications, which are programs designed for a specific task. Software is installed and resides on the hard disk and is loaded into memory when it is needed.

Although hardware and software are independent concepts, they require each other to function and neither can be realistically used on its own. Figure 2.13 shows how users interact with application software running on the computer system. It can be observed that the application software interacts with the operating system, which in turn communicates with the hardware. Information flow is indicated by the arrows.

Specifically, most algorithms can be implemented in either hardware or software. Generally, hardware-based algorithm implementation is much faster than software-based, but it can only perform a limited number of instructions, such as additions, comparisons, moves, and copies. Hence, software is utilized to create complex algorithms based on these basic instructions. The software that directly controls hardware is machine language. Software could also be written in low-level assembly language, which is strongly corresponding to machine language instructions, and translated into machine language through the assembler. However, many instructions are required to create even the elementary algorithms since machine languages are too simple. Hence, the majority of software is written with high-level programming languages, which are much easier and more efficient for programmers to use, describe, and develop algorithms, since they are much closer than machine languages to natural languages. Then, high-level languages are translated into machine languages using a compiler and an interpreter [22]. The interaction between different software levels and hardware is illustrated in Fig. 2.14.

Level 0 is hardware level. Programs in Levels 1, 2, and 3 consist of a series of numbers, which are hard for users to understand and interpret. Level 4 is the assembly language, which is a bit more user-friendly. The instructions at this level become readable and meaningful to users. Level 5 and 6 refer to the majority of software development. For instance, at Level 5, standard programming languages are generally used for development, such as C and C++. At Level 6, object-oriented programming languages become available, such as Java, Python, and .NET.

Firmware refers to a specific class of software that provides the low-level control for the specific hardware in a device. For instance, firmware can provide a standardized operating environment for the device's complex software, or act as the device's operating system that performs control, monitoring, and data manipulation functions. Firmware, such as the basic input-output system (BIOS) of computers, typically contains the basic functions of a device and provides services to higher-level software. Except the simplest, all electronic devices, such as computer systems, computer peripherals, embedded systems, consumer appliances, and Internet-of-thing (IoT) devices, contain firmware. It is stored in nonvolatile memories including ROM, EPROM, and flash memory, and is rarely or never changed after manufacture in contrast to the software. It can only be updated with special installation processes or with administration tools.Therefore, Firmware can be viewed as an intermediate form between hardware and software or a specific class of software embedded in hardware.

Sometimes both software and firmware are needed to be upgraded to correct errors or bugs, add features, or improve the device performance. For example, beta software or beta firmware is an intermediate version, which has not been thoroughly tested. Beta version is far more likely to have bugs than the polished final version since generally bugs or errors can only be manifested by putting the system in the real world.

Synapse ultrastructure refers to the physical components and dimensions that make up a chemical synapse. While neuronal, axonal, and dendritic changes are undoubtedly important, the synapse may represent the primary location for activity-dependent neural plasticity (i.e., the brain's flexibility). Research on synapse ultrastructure has involved describing specific synaptic components, quantifying the number of synapses in various brain regions, and quantifying the dimensions of various synaptic components. Quantifying synapses may be especially important for functional reasons when synapses change in number and/or dimension following neural activation (e.g., long-term potentiation), neural lesions (e.g., reactive synaptogenesis), learning (e.g., motor learning), and memory formation. Beyond providing a summary of these quantitative results, this article examines mechanisms for synaptic ultrastructural change and the potential functional relevance (e.g., increased efficacy) of the changes in synaptic ultrastructure that have been observed.

5.2 Communication Unit Modelling

We define a communication unit as an abstraction of a physical component. Communication units are selected from the library and instantiated during the communication synthesis step.

From a conceptual point of view, the communication unit is an object that can execute one or several communication primitives with a specific protocol. A communication unit is composed of a set of primitives, a controller and an interface. The complexity of the controller may range from a simple handshake to a complex layered protocol. This modular scheme hides the details of the realisation in a library where a communication unit may have different implementations depending on the target architecture (hardware/software).

Communication abstraction in this manner enables a modular specification, allowing communication to be treated independently from the rest of the design.

III COMMUNICATION UNIT MODELING

We define a communication unit as an abstraction of a physical component. Communication units are selected from the library and instantiated during the communication synthesis step.

From a conceptual point of view, the communication unit is an object that can execute one or several communication primitives with a specific protocol. These services can share some common resources (bus arbiter, buffering memory, buses) provided by the communication unit. The communication unit can include a controller which determines the protocol of the communication. The complexity of the controller may range from a simple handshake to a complex layered protocol. The services interact with the controller which modifies the communication unit state and synchronizes the communication. All accesses to the interface of the communication unit are made through these services. Such services also fix the protocol of exchanging parameters between the processes and the communication unit. The use of services allows to hide the details of the protocol in a library where a service may have different implementations depending on the target architecture (hardware/software).

Communication units differs from abstract channels in the way that they implement a communication with a specific protocol and realization (hardware/software). An abstract channel just specify the required services for a communication (Fig. 2).

Therefore, several abstract channels may be implemented by a single communication unit if it is able to provide all the required services. This operation is called a merge of abstract channels. Fig. 3 represent a merge of two abstract channels c1 and c3 on a communication unit cu1. Communication unit cu2 implement the communication offered by abstract channel c2.

This models enable the user to describe a wide range of communication schemes and most system level communication such as message passing or shared memory. Communication abstraction in this manner enables a modular specification, allowing communication to be treated independently from the rest of the design.