System Structure

Three alternatives for system structure are presented here. For comparison among alternatives, pros and

cons are listed to highlight distinctive attributes of each structure that make the structure more or less desirable.

System Structure Model – Alternative #1

PROS	CONS
Uses Internet – Inexpensive, relatively simple, reliable way to interconnect components	Security concerns with transmitting confidential data over the internet. Example: Hacker accesses data for military weapons locations and movements.
Logistics Software is global – Easier for network administrators to update and maintain
Centralized Database – Can be backed-up or mirrored using typical data center technology	One main database can provide a single point of failure if not backed-up properly.
Logistics Processor is simple and robust. Uses off the shelf industrial CPU, memory, network interface cards, etc.
Graphical user interface is an effective way to increase system reliability by limiting and controlling data access at the warehouse level.	None

Table 1: Alternative #1 – Internet Use

Figure 8: Tracking System (Global) Static Structure Model Alternative #1

Figure 9: Tracking System (Local) Static Structure Model Alternatives #1 & #2

System Structure Model – Alternative #2

PROS	CONS
High-tech, specially encoded satellite signals may offer better security than internet	Use of Satellites for network communi-cations – Can be unreliable in poor weather, increases complexity, increases cost
Centralized Database – Can be backed-up or mirrored using typical data center technology	Requires the use of communications antennae at all network locations, increases cost and complexity
Logistics Processor is simple and robust. Uses off the shelf industrial CPU, memory, network interface cards, etc.	Does not allow network-wide use of Logistics software. Software use is restricted to main data center
Graphical user interface is an effective way to increase system reliability by limiting and controlling data access at the warehouse level.	None

Table 2: Alternative #2 – Satellite Use

Figure 10: Tracking System (Global) Static Structure Model Alternative #2

Please refer to Figure 9 for the tracking system (local) static structure model of Alternatives #2.

System Structure Model – Alternative #3

PROS	CONS
Uses Internet – Inexpensive, relatively simple, reliable way to interconnect components	Security concerns with transmitting confidential data over the internet. Example: Hacker accesses data for military weapons locations and movements.
Logistics Software is distributed – Full software functionality is available at each warehouse location.	Increased access to tracking data through full blow Logistics Software can decrease system reliability by allowing potentially unskilled warehouse workers to access and manipulate data.
Distributed Database – Can offer greater security keeping accessible data at several locations, can eliminate single point of failure	Can make data access more difficult, adds complexity to data exchange (querying algorithms) and database update events. If not properly managed, can allow duplicates of master data files to exist in more than one location, takes more manpower to maintain
Logistics Processor is a fully functional PC, may offer increased functionality and savings at the warehouse level by serving a dual role as Logistics processor and PC	Logistics Processor becomes a full-blown network workstation, increases complexity over simplified industrial computer/GUI arrangement. Can decrease reliability by allowing less skilled warehouse personnel to access advanced, unfamiliar resources

Table 3: Alternative #3 – Hybrid Use

Figure 11: Tracking System (Global) Static Structure Model Alternative #3

Figure 12: Tracking System (Local) Static Structure Model Alternative #3

Assessment of Design Alternatives

Of the three alternatives presented above, alternative #1 is the most desirable. Alternative #2 adds a significant amount of cost and complexity, it is obviously less desirable. In some cases alternative #3 may offer more benefits than alternative #1, depending upon the level of functionality that the customer requires at the warehouse level. However, based on the preliminary goals and scenarios, and system requirements presented earlier, alternative #1 is the most suitable choice.