Layering and tiering

Internationalisation is often looked at from the point of view of asset centralisation and localisation, ffowever, the wider organisational setting needs to be taken into account as well. 

A commonly used maxim is global coordination and local operation, which relates to laying out the flow of information and coordination differently from the map 

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Please note that layers and tiers are two different concepts. Tiers mean the physical separation of subsystems—each subsystem runs on a different hardware or the same hardware but in different processes. In a multitiered system, the interaction between the subsystems is accomplished through remote procedure calls (RPCs). Any RPC involves network overhead and therefore has a performance penalty whether the remote procedure is on a separate hardware or on the same physical hardware but in a different process. Layers, on the other hand, are logical separations of the subsystems. Each layer can run on a different physical tier, or all layers can run on a single tier. The purpose of physical tiers is to leverage distributed hardware resources or to reuse a piece of software that is deployed on a different hardware that your system wants to leverage. The purpose of layered software architecture is to separate the system into highly cohesive and loosely coupled modules (see Chapter 2 for software development principles). 

There are good open standards such as ANSI 92 for a relational database system which conforms to the SQL standards. The leading proprietary database systems which conform to these standards include Oracle, Sybase, Informix and Progress. In order to ensure the maximum level of portability, the future direction of new software is likely to move towards the so called three-tier architecture. For example, Tier I contains the user interface. Tier II is the functionality layer and Tier III is the database layer. 

New solutions for layering and tiering the supply network are being tried out, such as co-location of suppliers with OEM plants in the auto industry. Meanwhile, the role of individual plants may be modified to allow more flexible response to local markets, for example by carrying out final assembly in local distribution centres. 

Figure 26.31 shows a typical landfill profile designed to meet U.S. EPA s MTG requirements.38 The upper subprofile comprises the cap, or cover, and includes the required 2-ft vegetative top cover, 1-ft lateral drainage layer, and low-permeability cap of barrier soil (clay), which must be more than 2 ft thick. This three-tier system also includes an optional FMC and an optional gas control layer. The guidance requires a 40-mil thick FMC. 

When you make a high layer cake or any tiered cake, you ll need an internal support system so that the cake remains stable, especially while you re frosting, decorating, or transporting it. With sticks inside the cake, you can build layer upon layer and not worry about the weight causing it to topple. 

To solve some problems of the two-tier architecture and improve the reliability and performance of the system, a three-tier architecture has been adopted. In a three-tier architecture, the business logic is separated from the presentation and data layers and becomes the middle layer between them. The presentation logic resides in the first tier (the client side), and the data logic in the third tier (the server side), and the business logic in the second tier (the middle) between both tiers. This solves the problems occurring with the two-tier architecture. Figure 6 shows a three-tier architecture where the business logic and some connection functions are placed in the second tier. 

The safety-related firmware is running on a microcontroller embedded in the power supply unit (cf. Fig. 3). It is a 3-tier structure as illustrated in Fig. 4. The lower layer called driver layer comprises the hardware related functionality. The application layer includes the management functionality required to run and monitor the system. The application is located at the upper layer and is triggering the required functionality. 

Wang and co-workers constructed a high-flux UE medium for oil/water emulsion separation [12]. As shown in Fig. 13.10, the medium consisted of a three-tier composite structure, i.e., a nonporous hydrophilic nanocomposite top layer, an electrospun PVA nanofibrous substrate middle layer, and a conventional nonwoven... 

The entire system is based on a tiered approach where three layers of technology are integrated into the overall treatment system, as illustrated in Chart 2. First, a distributed process control system is network linked to the various component subunits of the waste management system such as pH control, ion-exchange control, tank level control, etc. Next, are the recovery/treatment processes themselves. The final tier is a monitoring system which controls both the performance of the treatment systems and the discharge assurance of the plant effluent... 

Figure 8.2 A layered architecture in a Web application and how typically these layers are distributed among the three physical tiers.

TO MAKE THE CAKE AS PICTURED ON PAGE 30, bake two batches of cake in 8- and 6-inch pans. It s best to use two of each size for two layers. Extra batter from the 6-inch cake can be used to fill a small tray filled with cupcake liners. Prepare the Love Blossom flowers a few days before (page 226) and the Vanilla Whipped Buttercream (page 84), tinted pale lemon yellow. Use at least three different colors for the flowers, in pink tones—or as I do for baby boy showers, shades of pale blue. Fill, frost, and chill the cakes, then follow the directions to tier the layers on page 242-... 

To MAKE THE CAKE pictured on page 52> quadruple the recipe, in two 8-inch pans, and 2 6-inch pans. Triple the caramel—cream cheese frosting as well. Because this cake contains chunks of apples, don t try slicing it into thinner layers, or you ll have a mess on your hands. Fill and frost the cakes, then chill. Follow the directions for tiering a cake on page 242, and then your cake is ready to decorate. 

Trim the cake board of the second cake just to the edge of where it has been frosted, so that the board is not visible. This will support the second layer on the tiers. Place the second cake on top of the first, eyeballing to center it. If there is a third tier, repeat the process with the sticks and the cake board. 

It s important to have three round cake pans of the same size, whether 8 or 9 inch, because most cake recipes are created for these sizes. When you re in the mood for a dramatic cake, having three layers means your cake will be higher and more impressive. Basic aluminum cake pans can be purchased for less than 10 each. The smaller (4- or 6-inch) pans are an easy and fun way to make your cakes look more spectacular. Having a variety of sizes on hand will enable you to make tier cakes from one batch of batter. Quite often I will use one batch of batter to fill two 6-inch pans and one 4-inch pan—it s a fancier way to present a birthday cake, and it just looks more important. 

Brunner and Fiirst[431 reported the synthesis of a series of optically active, extended chelate phosphines, one of which was derived from the reaction of 5-bromo-l,3-di(bor-neoxymethyl)benzene (69) and bis(dichlorophosphino)methane (70). Technically, the product (-)-l,l-bis 3, 5 -di(borneoxymethyl)phenyl]phosphino methane (71) is both a first tier P- and 1,3-aryl-branched dendrimer. Excluding distortions, the maximum distance between the P atom and the most distant H atom(s) is 11.9 A for the two-layer ligand 71. The Rh-catalyzed [Rh(cod)Cl]2) hydrogenation of (a)-/V-acetamidocinnamic acid in the presence of 71 afforded a disappointingly low [5.2 % ee (/ )] optical induction. 

Multi-tier Architecture. An expansion of a client-server architecture to include a middle layer of software. The middle tier may run on a computer different from either the client or server computers. The middle tier isolates the client and server programs, so that changes in either of them do not require corresponding changes in the other. The middle tier acts as to receive, authenticate, and transform data as it passes between client and server computers. To make middle tier software easy to change and maintain, it is often written in Java, a modem object-oriented computer language that is available free on most of today s computer platforms. 

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