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Computer Architecture
Published in Bogdan M. Wilamowski, J. David Irwin, Fundamentals of Industrial Electronics, 2018
In the single-user environment, much time can be spent idling while waiting for user inputs or data transfers involving slow I/O devices. To exploit this idle time, multitasking and multiuser operating systems allow CPU time to be shared by multiple programs. The operating system passes control of the CPU from program to program, with each program allowed to execute for a small allotment of time or until it becomes stalled waiting for input/output. In this manner, the execution of a program is interleaved with the execution of other programs until it has completed. The end result is that programs execute concurrently with each program appearing to have exclusive control of the CPU. Linux [1] is an example of a multiuser, multitasking operating system used in a wide variety of embedded systems, PCs, workstations, and larger systems. Multiple users can issue commands to the operating system of one computer from different terminals, with each user running several programs at the same time.
Impact of the Use of IT on Business Systems
Published in Sharon Yull, BTEC National for IT Practitioners: Business Units, 2009
Operating systems can be classified into the following types:multiuser – allows two or more users to run programmes at the same time. In an organization some operating systems permit hundreds or even thousands of users to run programmes simultaneouslymultiprocessing – allows a programme to run on more than one CPUmultitasking – allows more than one programme to operate at the same timemultithreading – allows different parts of a single programme to run at the same timereal time – responds instantly to an input command.
Feedback Techniques for MIMO Channels
Published in George Tsoulos, MIMO System Technology for Wireless Communications, 2018
David J. Love, Robert W. Heath
Recent wireless innovations are improving bandwidth efficiency and reducing the deleterious effects of fading in wireless communication channels. Multiple antennas offer high capacity, enhanced resistance to interference, and reductions in fading thanks to diversity when arrays are used at both transmitter and receiver in a MIMO (multiple-input multiple-output) configuration. Broadband signaling, such as orthogonal frequency division multiplexing (OFDM), simplifies equalization in channels with significant multipath interference thus enabling larger bandwidth channels. Multiuser processing allows space, time, and frequency resources to be distributed among multiple users to improve network performance and system capacity.
A comparative analysis of computer-aided design team performance with collaboration software
Published in Computer-Aided Design and Applications, 2018
Keenan Eves, John Salmon, Jacob Olsen, Fred Fagergren
Collaboration has always been essential in engineering. When a change in engineering tools occurs, there is typically a change in the way collaboration is implemented. One of the largest engineering changes came with the use of computer-aided design (CAD) software in the 70s [1]. With the advent of CAD, group design on the drafting table moved to individualized design in the CAD environment. For over 30 years, engineers in industry have been placed in a much more isolated environment. However, the recent move towards geographically dispersed design teams in globalized companies has prompted the search for ways to bring engineers back into a more collaborative environment [25], [2], [4]. In an effort to improve collaboration and communication, and thereby expedite the design process, multi-user computer-aided design software (MUCAD) was created [18]. Like any new tool, the situations in which it should and can be used are uncertain. To gain a better understanding of the impact that MUCAD may have on team performance, this research compares four MUCAD teams and four single-user CAD teams across a number of dimensions. This research will help industry make informed decisions on how to use MUCAD and in what situations it would be valuable.
An efficient integrity based multi-user blockchain framework for heterogeneous supply chain management applications
Published in International Journal of Computers and Applications, 2023
Mani Deep Karumanchi, J. I. Sheeba, S. Pradeep Devaneyan
Let multi-user access policies be represented as M_P, the multi-user public key is defined as Multi_User_PublicKey, and the multi-user master key is represented as Multi_User_MasterKey. The two secret ciphertext parameters are given as c1 and c2. Table 2 presents the steps to generate cipher text.
Multi-user High Data Rate Indoor VLC Systems
Published in IETE Journal of Research, 2023
Safwan Hafeedh Younus, Aubida A. Al-Hameed, Jaafar M. H. Elmirghani
One of the main goals in VLC systems is to obtain a high data rate with a low BER. Thus, for multi-user VLC systems the signal to interference plus noise (SINR) ratio should be high to achieve these purposes. The performance of multi-user indoor VLC systems is strongly impaired by the mobility, the ISI and the multi-user interference. The simplest modulation technique for indoor VLC systems is OOK, and the BER of the conventional OOK modulation technique for indoor VLC systems is given as [36]: where is the complementary error function. For indoor VLC systems, the SINR can be expressed as [37, 38]: where is the photodetector's responsivity, () is the received power associated with logic 1, () is the received power assocaited with logic 0, is the total noise assocaited with the received signal, is the interferance power from the active branches that are assigned to other users, is the number of active branchess and is the set of the active branches that is allocated to active users. In this work, the total noise that is seen by each optical receiver is white Gaussian zero mean, with total standard deviation σt, The is classified into three componantes and given as [34, 39]: where represents the background shot noise component, is the shot noise component associated with the received signal and is the preamplifier noise component. The preamplifier used here is the p-i-n FET receiver designed in [40], which has an input noise current equal to 10 pA/.