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Anomaly detection in embedded systems using simultaneous power and temperature monitoring

Best PaperConference paper
Z. Abbasi, M. Kargahi, M. Mohaqeqi
in the 11th Information Security and Cryptography (ISCISC 2014), pp. 115-119, IEEE, Sep. 3-4, 2014

RTLB-DSR: A load-balancing DSR based QoS routing protocol in MANETs

Conference paper
Hanif Maleki, M. Kargahi, and Sam Jabbehdari
in the 4th International Conference on Computer and Knowledge Engineering (ICCKE 2014), pp. 728-735, Oct. 29-30

Preemption-Delay Aware Self-Triggered Controller: A Scheduler-Controller Codesign Approach

Best PaperConference paper
V. Panahi, M. Mohaqeqi, and M. Kargahi
In ICEE 2015, pp. , IEEE 2015

Joint Management of Processing and Cooling Power Based on Inaccurate Thermal Information in a Stochastic Real-Time System

Conference paper
M. Ghassemi, M. Mohaqeqi, and M. Kargahi
To appear in RTNS 2015

Thermal Analysis of Stochastic DVFS-Enabled Multicore Real-Time Systems

Journal paper
M. Mohaqeqi and M. Kargahi
In the Springer Supercomputing, Vol 71, No. 12, pp. 4594-4622, 2015

Abstract

This paper considers a multicore system, equipped with dynamic voltage/frequency scaling (DVFS), which runs real-time jobs with probabilistic characteristics. The DVFS policy directly affects the performance of this system as well as its power consumption through impacting both dynamic and leakage powers. While power consumption determines the processor thermal behavior, the temperature in turn affects the processor power consumption by impacting the leakage power. Additionally, temperature variation of a core is coupled with the thermal behaviors of the other cores, namely thermal effects of the surrounding components. These inter-effects make sophisticated relations between the nature of the stochastic real-time system and its performance, power consumption, and temperature behavior. In this paper, we first present an exact thermal analysis approach for the specified system considering these inter-effects. We then propose a scalable approximate method for thermal analysis of the system based on the exact analysis. The proposed analytical method outperforms the traditional simulation-based methods in terms of time complexity, by approximately three orders of magnitude, while introducing a relative error of less than 0.8 % for the mentioned setups. Also, we show the efficacy of the proposed analytical method in temperature-aware power minimization, resulting in significant reductions in the system-wide power consumption.

Keywords

Dynamic voltage and frequency scaling (DVFS) Markovian model Multicore processor Performance analysis Power management Real-time systems Thermal analysis

Reliability-Driven Scheduling of Time/Cost-Constrained Grid Workflows

Journal paper
S. Kianpisheh, N. Moghadam Charkari, and M. Kargahi
In the Elsevier Future Generation Computer Systems, Vol. 55, pp. 1-16, Feb. 2016

Abstract

Workflow scheduling in Grids and Clouds is a NP-Hard problem. Constrained workflow scheduling, arisen in recent years, provides the description of the user requirements through defining constraints on factors like makespan and cost. This paper proposes a scheduling algorithm to maximize the workflow execution reliability while respecting the user-defined deadline and budget. We have used ant colony system to minimize an aggregation of reliability and constraints violation. Three novel heuristics have been proposed which are adaptively selected by ants. Two of them are employed to find feasible schedules and the other is used to enhance the reliability. Two methods have been investigated for time and cost considerations in the resource selection. One of them assigns equal importance to the time and cost factors, and the other weighs them according to the tightness of satisfaction of the corresponding constraints. Simulation results demonstrate the effectiveness of the proposed algorithm in finding feasible schedules with high reliability. As it is shown, as an additional achievement, the Grid profit loss has been decreased.

Keywords

  • Workflow scheduling;
  • Reliability;
  • Real-time systems;
  • Grid computing;
  • Constrained optimization;
  • Ant colony optimization

Joint Management of Processing and Cooling Power Based on Inaccurate Thermal Information in a Stochastic Real-Time System

Conference paper
M. Ghassemi, M. Mohaqeqi, and M. Kargahi
In the 23rd Conference on Real-Time Networks and Systems (RTNS 2015), ACM, Nov. 4-6, pp. 45-54.

Abstract

This paper presents an analytical method for dynamic power management (DPM) of a stochastic firm real-time system. The proposed DPM solution dynamically adjusts cooling speed in the presence of a dynamic voltage scaling (DVS) policy to reduce the processor thermal-affected leakage power. We employ partially observable Markov decision process (POMDP) for controlling the cooling speed in situations that the ambient temperature is variable and the on-chip temperature sensor suffers from inaccurate sensing. Simulation results demonstrate that, in terms of total leakage and cooling power, the proposed method outperforms a heuristic solution while it closely follows the ideal behavior. It is also revealed that the proposed approach tolerates different levels of temperature sensor inaccuracy.

A Predictable Interrupt Management Policy for Real-Time Operating Systems

Conference paper
Javad Ebrahimian Amiri and Mehdi Kargahi
In the International Conference on Real-Time and Embedded Systems and Technologies (RTEST 2015), Oct. 2015

Energy-Efficient Scheduling for Stability-Guaranteed Embedded Control Systems

Conference paper
Alireza Salami and Mehdi Kargahi
Iin the International Conference on Real-Time and Embedded Systems and Technologies (RTEST 2015), Oct. 2015

Reliability-Constrained Response-Time Minimization in Soft Real-Time Systems

Conference paper
Ahad Mozafari Fard, Mehdi Ghasemi, and Mehdi Kargahi
In the International Conference on Real-Time and Embedded Systems and Technologies (RTEST 2015), Oct. 2015

Gauss-Jordan Matrix Inversion Speed-Up using GPUs with the Consideration of Power Consumption

Conference paper
M. Shirazi, M. Kargahi, F. Khunjush
In the 5th International Conference on Advanced Communications and Computation (INFOCOMP 2015), pp. 20-26, IARIA, June 2015

Temperature-Aware Adaptive Power Management: An Analytical Approach for Joint Processor and Cooling Mode Selection

Journal paper
M. Mohaqeqi, M. Kargahi
The Elsevier Sustainable Computing, Informatics and Systems, 2014. (In Press-Available Online: Aug. 27, 2014

Abstract
This paper presents a temperature-aware adaptive power management policy for a Markovian single-processor system equipped with a cooling fan working under variable ambient temperature. The method tries to minimize the jitter ofthe system performance, subject to a given power consumption constraint. Theadaptation is performed through simultaneous dynamic processor speed selection(to control power of the system processor) and dynamic fan mode selection(to control power of its cooling fan). First, we provide an analytical method forcalculation of the system power consumption and performance under some processorand fan speed setups. All the inter-e ects among the processor dynamicpower, leakage power, temperature, and the system stochastic properties aretaken into account in the calculations to reach more accurate analysis. Then, toadapt the system power consumption with respect to the variations of the ambienttemperature, we have used a model predictive control (MPC) approachbeside some optimizations based on the analysis to appropriately change theprocessor and fan speed setups. Simulation results show the ecacy of the proposedadaptive method with an emphasis on the preference of the consideredbacklog-dependent mode selection comparing to some traditional static modeselection methods.

Keywords: Thermal analysis, Adaptive power management, Dynamic voltageand frequency scaling (DVFS), Performance evaluation, Markovian model,Model predictive control (MPC)

Precautious-RM: A Predictable Non-Preemptive Scheduling Algorithm for Harmonic Tasks

Journal paper
M. Nasri, M. Kargahi
The Springer Real-Time Systems, Vol. 50, No. 4, pp. 548-584, July 2014

Abstract

A major requirement of many real-time embedded systems is tohave time-predictable interaction with the environment. More speci cally, theyneed xed or small sampling and I/O delays, and they cannot cope with large delay jitters. Non-preemptive execution is a known method to reduce the latterdelay; however, the corresponding scheduling problem is NP-Hard for periodictasks. In this paper, we present Precautious-RM as a predictable linear-timeonline non-preemptive scheduling algorithm for harmonic tasks which can alsodeal with the former delay, namely sampling delay. We derive conditions ofoptimality of Precautious-RM and show that satisfying those conditions, tightbounds for best- and worst-case response times of the tasks can be calculatedin polynomial-time. More importantly, response time jitter of the tasks is analyzedand it is proven that under speci c conditions, each task has either oneor two values for response time, which leads to improving the predictability ofthe system interaction with the environment. Simulation results demonstrateeciency of Precautious-RM in increasing accuracy of control applications.

Keywords

Non-preemptive scheduling,  Harmonic tasks,  Delay and jitter Accuracy enhancement,  Control applications,  Real-time systems

Analytical Leakage-Aware Thermal Modeling of a Real-Time System

Journal paper
M. Mohaqeqi, M. Kargahi and A. Movaghar
The IEEE Transactions on Computers, Vol. 63, No. 6, pp.1378-1392, June 2014.

Abstract

We consider a firm real-time system with a single processor working in two power modes depending on whether it isidle or executing a job. The system is equipped with dynamic thermal management through a cooling subsystem which canswitch between two cooling modes. Real-time jobs which arrive to the system have stochastic properties and are prone to softerrors. A successful job is one that enters the system and completes its execution with no timing or soft error. Appropriatenessof the system is evaluated based on its performance, temperature behavior, reliability, and energy consumption. It is noteworthythat these criteria have mutual interactions to each other: the stochastic nature of the system affects the success ratio of jobsbeside the system dynamic power, the leakage as well as dynamic power impacts the processor temperature, this temperatureaffects the leakage power, the cooling subsystem power, and the soft error rate, which the latter in turn impacts the systemreliability and the success ratio of jobs. This paper proposes an analytical evaluation method with a Markovian view to thesystem which considers these reciprocal effects. A number of simulation experiments are carried out to validate the accuracy ofthe proposed method.

Keywords

Analytical modeling, Firm real-time system, Leakage power, Performance, Temperature.

Lifetime Improvement of Real-Time Embedded Systems by Battery-Aware Scheduling

Journal paper
S. Manoochehri and M. Kargahi
International Journal of Electrical and Computer Engineering (IJECE), Vol. 12, No. 1, pp. 25-36, Aug. 2014. (In Persian)

Adaptive Scheduling of Real-Time Systems co-Supplied by Renewable and Non-Renewable Sources

Journal paper
M. Mohaqeqi, M. Kargahi, and M. Dehghan
ACM Transactions on Embedded Computing Systems (ACM TECS), Vol. 13, No. 1, Article 36:1-28, Nov. 2013

Abstract

Energy management is an important issue in today’s real-time systems due to the high costs of energy sup-plying. Using renewable, like wave, wind, and solar energy sources seem promising methods to address thisissue. However, because of the existing contrast between the critical nature of hard real-time systems andthe unpredictable nature of renewable energies, some supplementary energy source like electricity grid orbattery is needed. In this paper, we consider hard real-time systems with two renewable and non-renewableenergy sources. In order to reduce the costs, we present two dynamic voltage scaling controllers to minimizethe energy attained from the latter source. In order to handle variations of the environmental energy andworkload, the model predictive control approach is employed. One nonlinear approach beside one fast linearpiece-wise affine explicit controller are proposed. The efficacies of the proposed approaches have been inves-tigated through extensive simulations. Comparisons to an ideal clairvoyant controller as a baseline showthat, in the studied scenarios, the proposed controllers guarantee at least 78% of the baseline performance.Additional

Keywords

Dynamic voltage scaling (DVS), Energy harvesting, Model predictive control (MPC), Explicit MPC, Real-time systems

Utility Accrual Object Distribution in MPSoC Real-Time Embedded Systems

Journal paper
M. Mohaqeqi and M. Kargahi
Evier Journal of Computer and System Sciences, Vol. 79, No. 4, pp. 406-420, Jun. 2013

Abstract
This paper considers object-based real-time embedded systems on MPSoCs. Objects provide system services to the real-timetasks. Each task is subject to a time/utility function (TUF) which determines the accrued utility of the task according to itscompletion time. One major problem in such systems is to place the objects on the processing elements (PEs) in the MPSoCso as to maximize the total accrued utility. In this regards, we propose a utility accrual object distribution (UAOD) algorithmconsisting of two phases. In the first phase, the PEs are reserved for the most beneficial tasks in an offline manner. Thereservation is constituted of some proposed methods for object placement, object replication, deadline decomposition, anddeadline adaptation. For the objects which are not placed in the reservation, UAOD follows a load-balancing approach toplace them on the PEs. As the second phase, UAOD performs an online scheduling over the tasks assigned to each PE in theoffline object placement. An extension of this algorithm, namely UAOD* is also proposed for the situations where the exacttask execution-times are not known a priori. Simulation results reveal that the total accrued utility is improved with theproposed algorithms comparing to the traditional object placement methods.

Keywords

Deadline decomposition; object placement; object replication; MPSoC real-time systems; utility accrual scheduling;

Adaptive Scheduling of Energy Harvesting Real-Time Systems

Journal paper
M. Kargahi and M. Dehghan
The CSI Journal on Computer Science and Engineering (CSI-JCSE), Vol. 11, No. 1, pp. 1-10, Spring 2013. (In Persian).

Analytical Architecture-based Performability Evaluation of Real-Time Software Systems

Journal paper
F. Eshragh and M. Kargahi
The Elsevier Journal of Systems and Software, Vol. 86, No. 1, pp. 233-246, Jan. 2013

Abstract
Real-time systems are usually employed in dynamic and harsh environments. Real-time software,as one important part of such systems, potentially suffers from two problems: unpredictability inthe timing behavior which affects the software performance, and logical faults which affect thesoftware reliability. The former problem is mitigated by improving the software algorithm,architecture, and code. The latter problem is also relieved via software redundancy methods, even though these methods may adversely affect the software performance and architectural complexity. Despite these problems, it is expected to have a guaranteed service level in real-timesystems, which the service is defined as the successful completion of the software mission withinits deadline. In this paper, we propose an accurate and an approximate architecture-based analytical method for simultaneous performance and reliability (performability) evaluation of realtime component-based software. The accurate method is sound and precise but more complex inthe computations, while the approximate method is easy-to-follow with reasonable amounts ofcomputations. Examples of different configurations have been presented to show how well thelatter method approximates the former one. Some performability sensitivity analyses with respect to the software component properties have also been done for better depiction of the importance of employing the proposed analytical methods in finding and eliminating the software performability bottlenecks.

Keywords

Analytical modeling, component-based software, fault-tolerance, performability approximation, performability evaluation, real-time systems

Scheduling of Accuracy-Constrained Real-Time Systems in Dynamic Environments

Journal paper
M. Nasri, M. Kargahi, M. Mohaqeqi
IEEE Embedded Systems Letters. Vol. 4, No. 3, pp. 61-64, 2012

Abstract

Many real-time embedded systems are sensitive to both the accuracy and timeliness of job results. In this letter, two sources of inaccuracy are considered for such systems:  input data noise (IDN) due to the environmental transient noises, and  age of data (AD) related to the time of capturing data, which may depend on the length of time between capturing and using the input data. Thus, in the presence of one or more jobs in the system, some trade offs are needed among capturing data with an appropriate IDN when the environment is less noisy, reducing AD, and respecting the timeliness of jobs. Our emphasis in thecurrent study is to model firm real-time jobs having somethresholds for the inaccuracy and handle the aforementionedtradeoff by the system scheduler. An online accuracy-aware realtime scheduler is also proposed and evaluated.

Keywords

Accuracy-constrained scheduling, age of data,input data noise, Kalman filter, real-time embedded system

Performance Optimization Based on Analytical Modeling in a Real-Time System with Constrained Time/Utility Functions

Journal paper
M. Kargahi and A. Movaghar
IEEE Transactions on Computers. IEEE computer Society DL. IEEE Computer Society, Vol. 60, No. 8, pp. 1169-1181, Aug. 2011.

Abstract

We consider a single-processor firm real-time (FRT) system with exponential inter-arrival and execution times for jobs with relative deadlines following a general distribution. The scheduling policy of the system is first-come first-served (FCFS)and the capacity of the system is arbitrary. This system is subject to an arbitrary shaped time/utility function (TUF) whichdetermines the accrued utility of each job according to its completion time. It is considered that the system power consumptionat different working states is predetermined for each processor speed. We have proposed an exact analytical method for thecalculation of specific performance and power-related measures of the system. The resulting analytical formulations for the performance measures which are functions of the processor speed and system capacity are then optimized through appropriate selection of the former parameter using derivatives and the latter parameter employing numerical search methods. Someexperimental results are presented for different unimodal TUFs in systems with deterministic and exponential relative deadlines.For the latter distribution, the results are compared against similar results obtained through simulation for the non-preemptive earliest-deadline-first (NP-EDF) scheduling policy. The comparisons show that FCFS is superior to NP-EDF for some measures and TUFs.

Keywords

Analytical modeling, Firm real-time system, Optimization, Performance modeling, Time/utility function.

Utility Accrual Dynamic Routing in Real-Time Parallel Systems

Journal paper
M. Kargahi and A. Movaghar
IEEE Transactions on Parallel and Distributed Systems. IEEE computer Society DL. IEEE Computer Society, Vol. 21, No. 12, pp. 1822-1835, Dec. 2010.

Abstract

One of the main properties of today’s distributed and parallel systems, such as mobile ad-hoc networks and grids, is their heterogeneity in the available resources. Further, many applications of such systems are subject to Time/Utility Function(TUF) time constraints for jobs, unavoidable variability in job characteristics and arrivals, and statistical assurance requirementson timeliness behaviors. In this paper, we propose an exact analytical solution for performance evaluation of dynamic policiesused for routing of TUF-constrained Firm Real-Time (FRT) jobs among parallel single-processor queues with arbitraryprocessing rates and capacities. The analytical method can be used for the evaluation of the compliance of some importantstatistical assurance requirements. Furthermore, we present a utility-aware dynamic routing policy to improve the expected accrued utility of the parallel system. The policy called Maximum Expected Utility (MEU) behaves based on the informationgathered from the analytical solution. MEU is compared with some well-known Dynamic Routing (DR) policies for different TUFshapes and both cases of homogeneous and heterogeneous processors of a two-queue system. The comparisons show the efficiency of MEU for the former case and its good behavior in most situations for the latter case.

Keywords

Analytical modeling, Firm real-time systems, Performance modeling, Time/utility function, Utility accrual dynamic routing.

On the Handling of Node Failures: Energy-Efficient Job Allocation Algorithm for Real-time Sensor Networks

Journal paper
H. Karimi, M. Kargahi, N. Yazdani
Journal of Information Processing Systems, Vol. 6, No. 3, pp. 413-434, Sep. 2010.

Dynamic Routing of Real-Time Jobs among Parallel EDF Queues: A Performance Study

Journal paper
M. Kargahi and A. Movaghar
The Elsevier Journal of Computers and Electrical Engineering, vol. 36, No. 5, pp. 835-849, Sep. 2010.

Energy-Aware Scheduling of Execution-Instant Sensitive Real-Time Systems

Journal paper
L.Farzinvash and M. Kargahi
The CSI Journal on Computer Science and Engineering (CSI-JCSE), Vol. 7, No. 2 & 4 (b), pp. 34-47, 2009.

Stochastic DVS-based Dynamic Power Management for Soft Real-Time Systems

Journal paper
M. Kargahi and A. Movaghar
The Elsevier Journal of Microprocessors and Microsystems, vol. 32, No. 3, pp. 121-144, May 2008.

A Two-Class M/M/1 System with Preemptive Non Real-Time Jobs and Prioritized Real-Time Jobs under Earliest-Deadline-First policy

Journal paper
M. Kargahi and A. Movaghar
Scientia Iranica, Vol. 15, No. 2, pp. 252-265, March-April 2008.

A Non-Preemptive Two-Class M/M/1 System with Prioritized Real-Time Jobs under Earliest-Deadline-First Policy

Journal paper
M. Kargahi and A. Movaghar
Journal of Industrial and Systems Engineering, Vol. 1, No. 3, pp. 260-280, Fall 2007.

A Multiprocessor System with Non-Preemptive Earliest Deadline First Scheduling Policy: A Performability Study

Journal paper
M. Kargahi and A. Movaghar
Journal of Industrial and Systems Engineering, Vol. 1, No. 1, pp. 37-55, Spring 2007.

A Method for Performance Analysis of Earliest-Deadline-First Scheduling Policy

Journal paper
M. Kargahi and A. Movaghar
The Springer Journal of Supercomputing, Vol. 37, No. 2, pp. 197-222, August 2006.

Abstract

This paper introduces an analytical method to approximate the fraction of jobs missing their deadlines in a soft real-time system when the earliest-deadline-first (EDF) scheduling policy is used. In the system, jobs either all have deadlines until the beginning of service (DBS) and are non-preemptive, or have deadlines until the end of service (DES) and are preemptive. In the former case, the system is represented byan M/M/m/EDF+G model, i.e., a multi-sever queue with Poisson arrival, exponential service, and generallydistributed relative deadlines. In the latter case, it is represented by an M/M/1/EDF+G model, i.e., a singleserverqueue with the same specifications as before. EDF is known to be optimal in both of the above cases.The optimality property of EDF scheduling policy is used for the estimation of a key parameter, namely theloss rate when there are n jobs in the system. The estimation is possible by assuming an upper bound and alower bound for this parameter and then linearly combining these two bounds together. The resulting Markovchains can then be easily solved numerically. Comparing numerical and simulation results, we find that the existing errors are relatively small.

Keywords

Analytical methods, approximation methods, earliest-deadline-first (EDF), multiprocessor systems,performance modeling, soft real-time (SRT) systems

On the Optimality of RM and EDF for Non-Preemptive Real-Time Harmonic Tasks

Conference paper
M. Nasri, S. Baruah, G. Fohler, and M. Kargahi
To appear in the 22nd International Conference on Real-Time and Network Systems (RTNS 2014), pp. 331-330, ACM, Oct. 8-10, 2014.

A Framework to Construct Customized Harmonic Periods for Real-Time Systems

Conference paper
M. Nasri, G. Fohler, and M. Kargahi
To appear in the 26th Euromicro Conference on Real-Time Systems (ECRTS 2014), pp. 211-220, July 8-11, 2014.

Thermal Analysis of Periodic Real-Time Systems with Stochastic Properties: An Analytical Approach

Conference paper
M. Mohaqeqi and M. Kargahi
In the 21st International Conference on Real-Time and Network Systems (RTNS 2013), pp. 119-127, ACM, Oct. 16-18, 2013.

Analysis and Scheduling of a Battery-Less Mixed-Criticality System with Energy Uncertainty

Journal paper
S. Asyaban, M. Kargahi, L. Thiele, and M. Mohaqeqi
ACM Transactions on Embedded Computing Systems (TECS), Vol. 16, No. 1, Article 23: pp. 1-26, Oct. 2016

Abstract:

We consider a battery-less real-time embedded system equipped with an energy harvester. It scavenges energy from an environmental resource according to some stochastic patterns. The success of jobs is threatened in the case of energy shortage, which might be due to lack of harvested energy, losses originated from the super-capacitor self-discharge, as well as power consumption of executed tasks. The periodic real-time tasks of the system follow a dual-criticality model. In addition, each task has a minimum required success ratio that needs to be satisfied in steady state. We analytically evaluate the behavior of such a system in terms of its energy-related success ratio for a given schedule. Based on these results, we propose a scheduling algorithm that satisfies both temporal and success-ratio constraints of the jobs, while respecting task criticalities and corresponding system modes. The accuracy of the analytical method as well as its dependence on the numerical computations and other model assumptions are extensively discussed through comparison with simulation results. Also, the efficacy of the proposed scheduling algorithm is studied through comparison to some existing non-mixed- and mixed-criticality scheduling algorithms.

Analytical Leakage/ Temperature-Aware Power Modeling and Optimization for a Variable Speed Real-Time System

Conference paper
M. Mohaqeqi, M. Kargahi, A. Movaghar
In the 20th International Conference on Real-Time and Network Systems (RTNS 2012), pp. 81-90, ACM, Nov. 8-9, 2012.

A Method for Improving Delay-Sensitive Accuracy in Real-Time Embedded Systems

Conference paper
M. Nasri and M. Kargahi
In the 18th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2012), pp. 378-387, Aug. 20-22, 2012.

A Real-Time Data Aggregation Method for Fault-Tolerant Wireless Sensor Networks

Conference paper
P. Teymoori, M. Kargahi, N. Yazdani
In the Proceedings of 27th ACM International Symposium on Applied Computing (ACM SAC 2012), pp. 1176-1183, Mar. 2012.

Utility Accrual Object Distribution in Real-Time Systems

Conference paper
M. Mohaqeqi and M. Kargahi
In the Proceedings of the 16th IEEE International Conference on Parallel and Distributed Systems (ICPADS 2010), pp. 347-354, Dec. 8-10, 2010.

Adaptive Checkpoint Placement in Energy Harvesting Real-Time Systems

Conference paper
M. Dehghan and M. Kargahi
In the 18th International Conference on Electerical Engineering (ICEE 2010), pp. 932-937, July 08-10, 2010.

A Simulated Annealing Approach for Maximizing the Accrued Utility of an Isochronal Soft Real-Time System

Conference paper
A. Pourhaji-Kazem, N. Dadashkhani, M. Kargahi, H. Habibi-Aghdam
In the 2nd International Conference on Environmental and Computer Science (ICECS 2009), pp. 191-195, 2009.

Energy-Efficient Cluster-Based Scheme for Handling Node Failure in Real-Time Sensor Networks

Conference paper
H. Karimi, M. Kargahi, N. Yazdani
In the 8th IEEE International Symposium on Dependable, Autonomic and Secure Computing ( DASC 2009), pp. 143-148, Dec. 12-14, 2009.

On the Handling Node Failure: Energy-Efficient Job Allocation Algorithm for Real-time Sensor Networks

Conference paper
H. Karimi, M. Kargahi, N. Yazdani
In the 4th IEEE International Conference on Embedded and Multimedia Computing (EM-COM 2009), pp. 56-61, 2009

Guaranteeing Utility Level of a Firm Real-Time System Using Control Theory

Conference paper
M. Kargahi, M. Bazrafshan
Proceedings of the 14th International CSI Computer Conference, pp. 692-697, Oct. 20-21, 2009.

A Scheduling Algorithm for Execution-Instant Sensitive Real-Time Systems

Conference paper
L. Farzinwash, M. Kargahi
Proceedings of the 15th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA), pp. 511-518, Aug. 24-26, 2009.

Maximizing the Accrued Utility of an Isochronal Soft Real-Time System Using Genetic Algorithms

Conference paper
A. Pourhaji-Kazem, H. Seifzadeh, M. Kargahi, A. Movaghar, Shahriar Lotfi
Proceedings of the 8th IEEE/ACIS International Conference on Computer and Information Science, pp. 65-69, June 1-3, 2009.

A Method for Dynamic Software Updating in Real-Time Systems

Conference paper
H. Seifzadeh, A. Pourhaji-Kazem, M. Kargahi, A. Movaghar
Proceedings of the 8th IEEE/ACIS International Conference on Computer and Information Science, pp. 34-38, June 1-3, 2009.

An Efficient Distributed Flow Scheduling for Improving the Internet Bandwidth Usage

Conference paper
H. Hajabdolali, M. Kargahi, N. Yazdani
Proceedings of the 14th National CSI Computer Conference,Tehran, Iran, 2009.

Program Execution-Time Estimation in Soft Real-Time Systems using Loop-Counter Predictors

Conference paper
F. Varaminian, M. Kargahi
Proceedings of the 14th National CSI Computer Conference,Tehran, Iran, 2009.

EDF Queues: A Performance Study

Conference paper
M. Kargahi and A. Movaghar
Proceedings of the 11th Annual Int. CSI Computer Conference, Tehran, Iran, pp. 385-392, January 24-26, 2006.

Non-Preemptive Earliest-Deadline-First Scheduling Policy: A Performance Study

Conference paper
M. Kargahi and A. Movaghar
Proceedings of the13th Annual Meeting of the IEEE International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), Atlanta, Georgia, USA, pp. 201-210, September 27-29, 2005.

A Stochastic DVS-Based Dynamic Power Management for Soft Real-Time Systems

Conference paper
M. Kargahi and A. Movaghar
Proceedings of the IEEE International Conference on Wireless Networks, Communications and Mobile Computing (Wirelesscom/MobiWac 2005), Maui, Hawaii, USA, pp. 63-68, June 13-16, 2005.

Performance Analysis of a Dynamic Routing in Real-Time Parallel Queues

Conference paper
M. Kargahi and A. Movaghar
Proceedings of 10th Annual Int. CSI Computer Conference, Tehran, Iran, pp. 560-569, February 2005.

A Method for Performance Analysis of Earliest-Deadline-First Scheduling Policy

Conference paper
M. Kargahi and A. Movaghar
Proceedings of the IEEE International Conference on Dependable Systems and Networks (DSN), Florence, Italy, pp. 826-834, June 28th-July 1, 2004.

A New Approach for Performance Analysis of Earliest-Deadline-First Scheduling Policy

Conference paper
M. Kargahi and A. Movaghar
Proceedings of 9th Annual Int. CSI Computer Conference, Tehran, Iran, pp. 303-310, February 2004.

The Capabilities of Operating Systems for Accomplishment of Missions in Real-Time and Embedded Systems-A Survey

Conference paper
M. Kargahi
Operating System and Security Conference, Tehran, Iran, pp. 18-32, 2003.