Network Data Communications

The second more modern definition describes a Network comprised of more computers tied together with relatively few terminals on each computer. This second form of network became a reality with the mini computer revolution was spurred by acceptance Digitals PDP-8 and PDP-11 Mini computers in the 1960s and development of Digitals Network Architecture (DNA) in the 1970s. In order to clarify the distinction lets call the first form of "network" Data Communications and the second type a Digital Computer Network. 

Data Acquisition and Processing General Purpose Computers Data Communication Network Data Communication Computers Operations Support Workstations Technical Support Workstations... 

Saunders, S. 1994. Building a better token ring network. Data Communications 23(7) 75. 

Held, G. (1999). Data Communications Networking Devices, 4th ed. New York John Wiley Sons. 

A recent data communications protocol for Building Automation and Control Networks (BACnet), ASHRAE Standard 135-1995, is an important step to ensure that controllers made by different manufacturers can communicate with each other in a simple way, avoiding the expense of additional interface hardware and communication software. 

Network (including communication links). Legacy systems hardware and software have very limited security capabilities, and the vulnerabilities of contemporary systems (based on modern information technology) are publicized. Wireless and shared links are susceptible to eavesdropping and data manipulation. 

Wireless data communications devices are used to enable transmission of data between computer systems and/or between a SCADA server and its sensing devices, without individual components being physically linked together via wires or cables. In industrial chemical processing systems, these devices are often used to link remote monitoring stations (i.e., SCADA components) or portable computers (i.e., laptops) to computer networks without using physical wiring connections. 

WAP. The WAP provides the wireless data communication service. It usually consists of a housing (which is constructed from plastic or metal depending on the environment it will be used in) containing a circuit board, flash memory that holds software, one of two external ports to connect to existing wired networks, a wireless radio transmitter/receiver, and one or more antenna connections. Typically, the WAP requires a one-time user configuration to allow the device to interact with the local area network (LAN). This configuration is usually done via a Web-driven software application which is accessed via a computer. 

Currently, KARMA is in the prototyping phase. Although the hardware is connected via the high bandwidth network, it is necessary to implement the servers for data communications. Additionally, a completely new graphics package is in development for karma. The next two steps in terms of development are the turnkey and production versions of karma. 

For the water analysis, automation is clearly best achieved with an auto-injector for the mechanical handhng of the samples coupled with on-hne data capture, using the computer to analyse the peak data. Serious consideration was given to employing the very considerable in house automation experience to construct a purpose-built auto-injector. However, in the interests of a speedy implementation of the automatic system, it was decided to purchase a commercially available auto-injector and to concentrate the laboratory s efforts on the area of on-hne data capture. Interfacing the complete system assembly via a data communications network required the development of a special control device (commhox), which allowed the LGC hardware to run unattended hut provided an audible warning in event of a fault condition. 

Increases in processor speeds and storage capacity allowed these system to acquire and process data rapidly. Many fourth-generation systems became nodes in laboratory computer UMS networks. They communicate with host computers to receive instructions for analyses and for transferring results. Programs and values of parameters for specific analytical methods can be stored in memory and recalled by the analyst as needed. While the analyst found interaction with these systems easier, he or she became further removed from the system components and often more dependent on the vendor s software. Tailoring requirements to individual user requirements was often not viable with this approach. 

A second initiative is being developed by Dr. Ann Richard and coworkers at the EPA. The Distributed Structure-Searchable Toxicity (DSSTox) public database network is a flexible community-supported, web-based approach for the collation of data. It is based on the SDF format for the representation of chemical structure. It is intended to enable decentralized, free public access to toxicity data files. This should allow users from different disciplines to be linked. Public, commercial, industry, and academic groups have also been asked to contribute to, and expand, the DSSTox public database network. Data from potentially any toxicological endpoint can be collated in the DSSTox public database network, including both human health, and environmental endpoints (Richard et al 2002 Richard and Williams, 2002). 

There are two primary definitions for the term Network. One definition for a network describes a few computers with lots of terminals. Such installations frequently have grown from a batch environment with a large central mainframe computer to which terminals have been added. The term data communications is used to describe terminal (or terminal like) communications between the terminal and host. This is perhaps the most mature communications area. It was developed initially to support Teletype Equipment over telephone lines. 

Network GAMP (2001) A network is a data communications system that links two or more computers and peripheral devices. It consists of cabling, the network hardware, and communications software. 

The construction of the SPEEDI network was started in 1986, in order to establish the data communication lines between the SPEEDI operations center, the Science and Technology Agency (STA) and prefectural governments in which nuclear plants are placed, according to a national plan for the improvement of the national emergency countermeasure system in Japan. 

The data communication network system of SPEEDI consists of five main organisations, which are... 

Horak, R. Miller, M.A. Fundamentals of data communications. In Communications Systems Networks Voice, 42. Data, and Broadband Technologies, Consulting Ed. M Tbooks Division of MIS Press, Inc. Subsidiary of 43. Henry Holt and Company, Inc. New York, 1997 ... 

Karabek, R. Data Communications in ATM Networks. PhD thesis, RWTH Aachen University (1998)... 

These traditional methods were very inefficient, slow, and unreliable. The picture has now tottilly changed through computer networking. By the use of the data communication links connecting computers and the additional devices making possible the transfer of information, till the information preprocessed at the partner sites can be easily, efficiently, immediately, and reliably downloaded from the partner computers to the local machine. 

Besides outcome measures, interviews represent a possible data-collection method. Whether directed or not (e.g., Sinclair 1990) they can produce critical incidents, human factors examples, or networks of communication (e.g., Drury 1990a), which have vrilue as part of an audit procedure. Interviews are routinely used as part of design audit procedures in large-scale operations such as nuclear power plants (Kirwan 1989) or naval systems (Mrilone et al. 1988). 

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