• Journal of Computing Science and Engineering
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• v.9 no.2
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• pp.108-117
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• 2015

Interrupt handling is generally separated from process scheduling. This can lead to a scheduling anomaly and priority inversion. The processor can interrupt a higher priority process that is currently executing, in order to handle a network packet reception interruption on behalf of its intended lower priority receiver process. We propose a new network interrupt handling scheme that combines interrupt handling with process scheduling and the priority of the process. The proposed scheme employs techniques to identify the intended receiver process of an incoming packet at an earlier phase. We implement a prototype system of the proposed scheme on Linux 2.6, and our experiment results show that the prototype system supports the predictable real-time behavior of higher priority processes even when excessive traffic is sent to lower priority processes.

• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.881-892
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• 1999

In this paper we consider a polling system with two classes of stations; high priority and low priority. High priority stations are polled more frequently than low priority stations. We derive an exact and explicit formula for computing the mean waiting times for a message when the arrival processes are batch Poisson. In general the formula requires to solve two sets of simultaneous equations By specializing them to the case of two priority classes we greatly reduce the number equations and provide a simple formula for mean waiting times. We apply the results to a data communication processing system and show that the overall mean waiting time can be reduced by using priority polling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.5
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• pp.218-228
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• 1985

The input messages in communication network are processed according to their priority. If the messages which are had different types of priority are excessively entered to communication network in such prioruty process, and if high priority messages are continuously entered, the messages which are had law priority are experinenced delay beyond their priority. In this case, we proposed average delay compensation method to compensate contonuous delay in low priority messages.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.264-267
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• 2002

This paper proposed a effective priority selection algorithm named weighted round-robin algorithm and show the implementation result of DMAC priority selection module using prosed weighted round-robin algorithm. I parameterize timing constraints of each functional module, which decide the effectiveness of system. Proposed weighted round-robin algorithm decide the most effective module for data transmission using parameterize timing constraints and update timing parameter of each module for next transmission module selection. I implement DMAC priority selection module using this weighted round-robin algorithm and can improve the timing effective for data transmission from memory to functional module or one functional module to another functional module.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.291-297
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• 2003

This paper considers discrete-time two-class Ge $o^{X/}$G/1 queues with preemptive repeat priority. Service times of messages of each priority class are i.i.d. according to a general discrete distribution function that may differ between two classes. Completion times are derived for the preemptive repeat identical and different priority disciplines. By using the completion time, the stability condition for our system is investigated.d.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.156-164
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• 2005

A comparative analysis of an ice storage system has been performed on the operation cost for the four control strategies, i.e., chiller priority and chiller downstream, chiller priority and chiller upstream, storage priority and chiller upstream, storage priority and chiller downstream. Main components of the ice storage system are an ice-on-coil storage tank and a screw compressor chiller. With the simulation program, the operation cost has been evaluated from the economics of an ice storage system. It is found that the operation cost of the ice storage system is strongly dependent on the control strategy, i.e., chiller priority or storage priority, but less affected by the arrangement method, i.e., chiller upstream or chiller downstream. In case of the maximum load day, the control strategy with chiller priority and chiller upstream is supposed to obtain the reduction of operation cost. However, it is found that the control strategy with storage priority and chiller downstream is the best economical operation for most summer seasons except the maximum load day.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.995-1002
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• 2018

A Contention Access Period(: CAP) with high contention in priority-based MAC protocols can result in higher number of collisions and retransmissions. High-Priority traffic dominates low-priority traffic during CAP depleting low-priority traffic, adversely affecting WBAN throughput, delay, and energy consumption. This paper proposes a Emergency data-First-Priority MAC(: EFP-MAC) superframe structure that is able to reduce contention in the CAP period, and provides a fair chance for low-priority traffic. As a result, the proposed Emergency data-First Priority MAC(; EFP-MAC) The Simulation results show that the proposed MAC achieves lower energy consumption, higher throughput and low latency than the IEEE 802.15.4 standard.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2636-2656
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• 2013

To improve the cooperative efficiency of node cooperation and multiple access performance for multihop wireless networks, a priority-differentiated cooperative medium access control protocol with contention resolution (CRP-CMAC) is proposed. In the protocol, the helper selection process is divided into the priority differentiation phase and the contention resolution phase for the helpers with the same priority. A higher priority helper can choose an earlier minislot in the priority differentiation phase to send a busy tone. As a result, the protocol promptly selects all the highest priority helpers. The contention resolution phase of the same priority helpers consists of k round contention resolution procedures. The helpers that had sent the first busy tone and are now sending the longest busy tone can continue to the next round, and then the other helpers that sense the busy tone withdraw from the contention. Therefore, it can select the unique best helper from the highest priority helpers with high probability. A packet piggyback mechanism is also adopted to make the high data rate helper with packet to send transmit its data packets to its recipient without reservation. It can significantly decrease the reservation overhead and effectively improve the cooperation efficiency and channel utilization. Simulation results show that the maximum throughput of CRP-CMAC is 74%, 36.1% and 15% higher than those of the 802.11 DCF, CoopMACA and 2rcMAC protocols in a wireless local area network (WLAN) environment, and 82.6%, 37.6% and 46.3% higher in an ad hoc network environment, respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.1
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• pp.62-68
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• 2005

This paper presents a scheme to enhance fixed priority scheduling algorithms on multiprocessors. This scheme gives the highest priority to jobs with zero laxity and schedules them Prior to other jobs. A fixed priority algorithm employing this scheme strictly dominates the original one; it can schedule all task sets schedulable by the fixed priority algorithm and some task sets not schedulable by the fixed priority algorithm. Simulation results show that the proposed scheme improves fixed priority algorithms in terms of the number of schedulable task sets and schedulable utilization bound.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.93-99
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• 1997

Most of the past studies on FMS scheduling problems may be classified into two classes, namely off-line scheduling and on-line scheduling approach. The off-line scheduling methods are used mostly for FMS planning purposes and may not be useful real time control of FMSs, because it generates solutions only after a relatively long period of time. The on-line scheduling methods are used extensively for dynamic real-time control of FMSs although the performance of on-line scheduling algorithms tends vary dramatically depending on various configurations of FMS. Current study is about finding a better on-line scheduling rules for FMS operations. In this study, we propose a method to create priority functions that can be used in setting relative priorities among jobs or machines in on-line scheduling. The priority functions reflect the configuration of FMS and the user-defined objective functions. The priority functions are generated from diverse dispatching rules which may be considered a special priority functions by themselves, and used to determine the order of processing and transporting parts. Overall system of our work consists of two modules, the Priority Function Evolution Module (PFEM) and the FMS Simulation Module (FMSSM). The PFEM generates new priority functions using input variables from a terminal set and primitive functions from a function set by genetic programming. And the FMSSM evaluates each priority function by a simulation methodology. Based on these evaluated values, the PFEM creates new priority functions by using crossover, mutation operation and probabilistic selection. These processes are iteratively applied until the termination criteria are satisfied. We considered various configurations and objective functions of FMSs in our study, and we seek a workable solution rather than an optimum or near optimum solution in scheduling FMS operations in real time. To verify the viability of our approach, experimental results of our model on real FMS are included.