Tier 2 nodes

Tier 1 nodes function as the primary sensor acquisition platforms for the smart garment. T1 nodes are more numerous than T2 nodes but are smaller, less powerful, and lower-cost devices. Fig. 27.17 shows the front and back of the current T1 board and Table 27.2 outlines specific features. As shown in Fig. 27.17, a USB-style connector is used to connect the board to the I C network for communication and to provide power to the board. (The USB-style connector is only used for prototyping... 

Figure 27.17 Front and back of Tier 1 node show CPU, accelerometer, compass, and gyroscope.

A three-tiered architecture includes one more node between the client and the database server—the middle tier. In a three-tiered architecture, business logic is offloaded from the client and the database server nodes to the middle tier. In fact, you can choose to further distribute the business logic among more than one middle tier node and still call it a three-tiered (or K-tiered) architecture because the idea is similar. Note that the tiers do not have to be physically separated. You can have both the middle tier server and the database server collocated on the same physical computer but running in different processes with separate memory spaces. Modem hardware architecture can partition a single hardware box into multiple virtually separate computers or domains. Typically, a three-tiered architecture supports a Web-based thin client although it can also work with a rich client. 

Deployment of software is shown here against this physical model, with different software components shown on different hardware nodes for example, the software components in the four-tier system are shown in Figure 12.5. Note that software component requirements, such as memory and storage space, can be modeled as attributes and matched against the corresponding attributes of the hardware. If needed, you can also explicitly specify the effect of actions, such as node failures (failover requirements) or network load, against such a model. 

Demons and Variables. ALEX provides a three-tiered knowledge representation structure of contexts, demons, and variables. Contexts are top-level structures that isolate individual major areas of the problem under analysis. Demons are the central knowledge representation structure they are essentially frame-based information storage nodes with slots both to hold information on the content of the demon and to reflect the impact of one or more variables on the status of the demon. Variables may hold user-input, default, or calculated information. 

Figure 2 The first three tiers of states that develop from the parent node are shown. The nonzero matrix elements are shown as lines linking the states. Note that there may be several paths from the parent node to each descendent node.

The AI technique introduced by Tietz and Chu was developed further by Chang and Wyatt (14,15) in their studies of the multiphoton excitation of degenerate anharmonic oscillator-rigid rotor systems (such as tetrahedral and octahedral molecules). Two search strategies were used in these studies. In the first, the best-first strategy, only the most important nodes in each tier are expanded. For example, nodes 1 and 2 in tier 1 of Figure 3 are expanded, yielding nodes 5, 6, and 7 from node 1 and nodes 6 (a repeat) and 8... 

To derive the SPE condition we evaluate the event tree backward from the leaf nodes. Since the event tree in the figure represents the case where the buyer gets the largest possible perfect equilibrium share, when the supplier makes the offer, she settles for the minimum perfect equilibrium share m. When the buyer makes the offer, she receives the maximum gain possible and leaves tt - M5 to the supplier. In case the bargaining breaks down, the supplier receives her outside option W5. The offers at the next tier follows the same logic. When the buyer makes the offer, she leaves tt — to supplier as before. If the supplier makes the offer, she settles for the least amount she expects to gain in the future, which is equal to... 

Detectability is defined as the time it takes for the buyer to realize that a disruption to supply network has occurred. Modeling the propagation of disruption information in a supply chain depends on the way nodes communicate with one another. Under the best-case scenario, each supplier, independent of its tier, communicates directly with the buyer. This is a very optimistic scenario since it requires every supplier to know the end destination of its product and to establish a direct connection with the buyer. The next best scenario assumes that every disrupted supplier reports to its immediate buyer. This situation is more realistic however, it does not ensure that the information will reach the primary buyer promptly since the immediate buyer of the disrupted supplier may not share the information with his customers or with the main buyer. Another scenario would be to assume that the information flows randomly in the supply chain network. This scenario may be perceived as pessimistic at first, but the method can be customized to better model the reality. 

There are several ways to include detectability of disruption risks in supply chain risk models. One way is to directly use the values in the MFPT matrix, the ntij values, and create an objective function to minimize the number of transitions between suppliers and the buyer. Otherwise, the MFPT values may not be suitable to use directly in risk quantification since values in the MFPT matrix are in transitions and need to be transformed to actual time units (e.g., hours, days, or weeks) for proper use in disruption quantification. This transformation to time units is supply chain specific, since the speed with which the information spreads through the nodes depends on the information technology systems implemented at each node and the availability and strength of connection among the nodes. For instance, if a buyer has implemented an ERP system that allows communication with all tiers of his supply chain, he would have much better connectivity to any supplier and the transition times would be much shorter than buyers that do not have a similar visibility. We call the time it takes any disruption news to reach from node i to j as the disruption delay between nodes i and j and denote it as Aij. 

Tier 1 and Tier 2 nodes are connected via an I C bus and are distributed across the body as shown in Fig. 27.14. I C is a two-wire network interface with shared clock (SCL) and data lines (SDA). The four-wire on-fabric (sewn or woven) network described in Section 27.2 consists of the two wires for the I C bus and two wires for power and ground. The T1 nodes on the network monitor the SDA line for quiet periods to transmit. Data collisions are resolved through arbitration to ensure that one node cannot control the network. The T1 nodes arbitrate the I C bus as a multimaster system and communicate to the T2 node. To maintain synchronization across the T1 nodes a single timer node pulses the bus to initiate transmission from each T1 node. This synchronization mitigates timing irregularities and ensures updates from all... 

Figure 27.14 Placement of Tier 1 and Tier 2 nodes with an electronic textile for the applications described in this chapter.

Table 27.1 Comparison of features between Tier 2 node generations...

Demand for supply chain products or services originate at the customer tier and it is transmitted upstream along the supply chain (Fig. 2.2). In many cases, customer nodes in this tier are an aggregation of individual customers clustering in a particular geographical location. 

The distribution tier receives customer requirements and is responsible for delivering required products or services. It involves such general units as warehouses, distribution centers, and cross-docking points. These units are grouped into distribution sub-tiers. Alternatively, supply chain units in the distribution tier can be classified as wholesalers, retailers, and brokers. Third-party logistics providers present a special case for belonging to the distribution tier. In some situations, these can be represented by a single supply chain node. 

The supply tier provides materials to manufacturing according to orders received. This tier can be divided into sub-tiers, linking raw materials suppliers, secondary suppliers, and direct suppliers. Representation of the supply tier depends upon the importance of supplied materials. Suppliers providing widely available and substitutable materials do not need to be represented by individual nodes. 

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