Schedulability Analysis Research Articles

Formal Modeling and Verification of Embedded Real-Time Systems: An Approach and Practical Tool Based on Constraint Time Petri Nets

Modeling and verification of the correct behavior of embedded real-time systems with strict timing constraints is a well-known and important problem. Failing to fulfill a deadline in system operation can have severe consequences in the practical case. This paper proposes an approach to formal modeling and schedulability analysis. A novel extension of Petri Nets named Constraint Time Petri Nets (C-TPN) is developed, which enables the modeling of a collection of interdependent real-time tasks whose execution is constrained by the use of priority and shared resources like processors and memory data. A C-TPN model is reduced to a network of Timed Automata in the context of the popular Uppaal toolbox. Both functional and, most importantly, temporal properties can be assessed by exhaustive model checking and/or statistical model checking based on simulations. This paper first describes and motivates the proposed C-TPN modeling language and its formal semantics. Then, a Uppaal translation is shown. Finally, three models of embedded real-time systems are considered, and their properties are thoroughly verified.

Evaluation of Operation Patterns and Ship Needs on the Paciran-Bawean Crossing Route, East Java Province

KMP. Gili Iyang which operates on the Paciran-Bawean route has 2 trips/week with a crossing distance of 80 miles. However, the operation of ships on long distances is not balanced with the ideal number of trips, resulting in a buildup of vehicles and passengers at Paciran Port. Where the time needed to sail is 8 hours. Therefore, this research aims to determine the frequency, number of ships needed and efficient ship operation patterns according to the needs of service users. The analysis in this research includes load factor analysis, passenger and vehicle growth prediction analysis, ship frequency analysis, ship number requirement analysis, and scheduling analysis. From this analysis, it was concluded that the ideal number of ship frequencies on the Paciran-Bawean route is 1 trip/week, and the number of ships that must be operated is 1 ship, and the results of the analysis show that the schedule for ships serving the Paciran-Bawean route is still not yet in accordance. So rescheduling is needed from 2 trips/week to 1 trip/week and forecasting is needed for the next 5 years so that the number of trips is in accordance with the needs of service users, as well as the operation of the KMP. Dharma Kencana on the Paciran- Bawean route so that there is a balance between service users and service providers.

Evaluation Of Crossing Vessel Operation Patterns On The Kariangau-Penajaj Port Kariangau East Kalimantan Province

Kariangau Ferry Port is a port in Balikpapan City which serves the Kariangau-Penajam route with a total of 12 ships per day. Ship operations on this route are not balanced with minimum service standards for ship operations and the ideal number of trips so that when the ship sails it does not carry maximum passengers or vehicles. This research aims to increase the efficiency of ship use based on the current ideal number of ships and trips and minimum service standards for ship operations. The method used in this research is analysis load factor, analysis of minimum service standards for ship operations, analysis of ship needs, and scheduling analysis. Based on the results of the calculation analysis load factorobtained on averageload factorfor passengers it is currently 1% and for vehicles it is currently 57%. The change in ship operating patterns on the Kariangau-Penajam route now from existing conditions, which was obtained through the results of analysis of the calculation of the need for the number of ships and analysis of optimal ship schedules, has caused differences between the current ship operating patterns and the planned operation patterns resulting from the calculations. The operating pattern of this plan is calculated based on the number of trips and the number of ships according to the needs of service users so that ships on this route can carry maximum passengers and vehicles.load factorideal 65%.

Analisa Manajemen Waktu Pekerjaan Renovasi Pembangunan Cafe Terakota

Successful execution of a construction project on time is one of the most important goals, for both owners and contractors. As in the construction of terracotta cafee renovation work which regressed to week 14, causing inaccuracies between the planning schedule and the construction implementation schedule. This study aims as an evaluation to get the fastest time acceleration using the CPM (Critical Path Method) cut and crashing method. From schedule data, RAB, and analysis of wage prices and weekly progress, a network is created and determines the critical path to then be cut and crashed. From the results of the study, it was found that the acceleration of the project can be done up to 77 days 6 days faster than normal days, which are 83 days with an acceleration cost of Rp. 337,649,065.79 or an increase of Rp. 20,125,000 from the normal cost of Rp. 317,524,065.79. The percentage of comparison due to the acceleration of the project using the critis cut and crash path method, that is, for an acceleration time of 5.59% faster than normal time. Meanwhile, the acceleration fee is 6.34% greater than the normal cost. So with this research, the costs incurred become more expensive, but the project completion time becomes shorter and more concise. It done on July 2rd, 2023.

Time-predictable task-to-thread mapping in multi-core processors

The performance of time-predictable systems can be improved in multi-core processors using parallel programming models (e.g., OpenMP). However, schedulability analysis of parallel applications is a big challenge due to their sophisticated structure. The common drawbacks of current task-to-thread mapping approaches in OpenMP are that they (i) utilize a global queue in the mapping process, which may increase contention, (ii) do not apply heuristic techniques, which may reduce the predictability and performance of the system, and (iii) use basic analytical techniques, which may cause notable pessimism in the temporal conditions. Accordingly, this paper proposes a task-to-thread mapping method in multi-core processors based on the OpenMP framework. The mapping process is carried out through two phases: allocation and dispatching. Each thread has an allocation queue in order to minimize contention, and the allocation and dispatching processes are performed using several heuristic algorithms to enhance predictability. In the allocation phase, each task-part from the OpenMP DAG is allocated to one of the allocation queues, which includes both sibling and child task-parts. A suitable thread (i.e., allocation queue) is selected using one of the suggested heuristic allocation algorithms. In the dispatching phase, when a thread is idle, a task-part is selected from its allocation queue using one of the suggested heuristic dispatching algorithms and then dispatched to and executed by the thread. The performance of the proposed method is evaluated under different conditions (e.g., varying the number of tasks and the number of threads) in terms of application response time and overhead of the mapping process. The simulation results show that the proposed method surpasses the other methods, especially in the scenario that includes overhead of the mapping. In addition, a prototype implementation of the main heuristics is evaluated using two kernels from real-world applications, showing that the methods work better than LLVM's default scheduler in most of the configurations.

A hybrid forecasting model to predict the duration and cost performance of projects with Bayesian Networks

This paper presents a new hybrid forecasting model to predict the final time and cost of a project using input parameters from the project scheduling and risk analysis literature. The hybrid method integrates two well-known risk models. A Structural Equation Modeling constructs and validates a theoretical risk model to represent known relations between project indicators and the project performance. A Bayesian Networks is used to train the theoretical model using artificial project data from the literature. These two integrated models are then used to predict the final duration and cost of a new unseen project.The accuracy of this integrated model is compared with other well-known forecasting methods from the literature. The computational experiments on a set of 33 empirical projects show that risk models demonstrate a noteworthy advantage for time and cost forecasting. To show the usefulness of this method, it is compared with a set of known machine learning forecasting algorithms.These static predictions of risk models are also compared with some well-known dynamic forecasting methods that continuously update the time/cost predictions along the project progress. These dynamic models make use of predictors from the earned value management and earned duration management literature. The results show that the static risk models offer more precise forecasts than the dynamic methods in the first half of the project progress for time forecasting, but then loose their power in favor of the dynamic forecasts.

Analysis of Fork-Join Scheduling on Heterogeneous Parallel Servers

Analysis of Fork-Join Scheduling on Heterogeneous Parallel Servers

Effect of Work Experience on Marital Satisfaction and Marital Conflict among Normal and Shift Schedule Professionals of Ekiti State, Nigeria

Separation, single parenthood and divorce are all on the rise. The commotion of the work place mix with family obligation and expectation play a role in these marital challenges. The study examined Marital satisfaction and marital conflict the comparative analysis of shift schedule and normal working hours employee in Ekiti-state, Nigeria. A total of 700 staff (389 normal working hours schedule and 381 shift schedules) were selected, Slovin formula was employed to get a sample of the population. Participants ages ranged between <18 ->55 years. These research instruments were used to generate data from participants, namely Enrich Marital Satisfaction Scale(EMSC)by Blaire et al 1987 and Kansas Marital Conflict Scale(KMSC) by Eggerman et al 1985. Data were analyzed with the use of analysis of variance (Anova and independent t-test). The findings show that there is a significant difference in the level of marital conflict reported by the professionals (Nurses, Police officers, Correctional officers and Civil servants)F(3,766)=40.58.P<.01. Observation of the means shows correctional officer (x=75.83) has highest level of marital conflict followed by police (x=72.86) then Nurses ( x= 66.34) and lastly civil servant. However there is also a significant difference in the marital satisfaction of the professionals F(3,766)=6,67.P<.01.Nurses reported highest score on marital satisfaction followed by Civil servants then police officer and and lastly correctional officer. Findings were discussed in relation to the existing literature on marital satisfaction and marital conflict

Valjean, a universal post-processing tool for neutronics

Valjean is an open-source framework for workflow scheduling, post-processing and data analysis in verification and validation of neutronics codes. It provides native support for reading TRIPOLI-4® and APOLLO3® output files, but can be easily extended to other codes. We present here the structure of the Valjean package, together with a few typical usage examples.

A BSF‐EDZL scheduling algorithm for heterogeneous multiprocessors

AbstractTo improve the performance of real‐time systems, heterogeneous asymmetric multiprocessors are proposed. Heterogeneous asymmetric multiprocessor architecture allows the system to better match computational resources to meet the needs and dynamic workload of each application. The benefits of system performance and reduced power consumption cannot be fully exploited unless proper task scheduling and task allocation methods are implemented at the operating system level.The EDZL scheduling algorithm has been shown to be a better scheduling algorithm in heterogeneous multiprocessor platforms. In this paper, the BSF‐EDZL (best speed fit for earliest deadline first until zero‐laxity) performance asymmetric multiprocessor scheduling algorithm is proposed, and an effective schedulability analysis is performed. The algorithm selects an appropriate processor for non‐zero relaxation highest priority task rather than the fastest processor when assigning tasks. Experimental results show that the proposed BSF‐EDZL scheduling algorithm can schedule a larger set of tasks than the ordinary EDZL scheduling algorithm.

Pemodelan 3D Jembatan Lengkung, Studi Kasus Jembatan Bukit Sulap, Menggunakan Software Autodesk Revit

Infrastructure is an essential sector in a country, and infrastructure development reflects the country's progress. Infrastructure development is a priority, but the implementation of infrastructure projects needs to pay attention to time, costs and quality. Building Information Modeling (BIM) has the potential to minimize errors and increase efficiency. BIM is a method that was originally applied to the AEC (Architecture, Engineering and Construction) industry. BIM technology makes it possible to create 3D building models that contain information, analysis of work volume calculations, scheduling, and cost calculations. There is several software that applies BIM technology such as Autodesk Revit, Autodesk Advanced Steel, Tekla Structures and Navisworks. BIM technology has been widely applied in construction projects in Indonesia, be it buildings, roads or bridges. In this research, modelling of a steel truss bridge with an arch type was carried out using Autodesk Revit software. This research was conducted to determine the capabilities and limitations of Autodesk Revit software in modelling arch-type steel frame bridge structures. The modelling in this research uses DED (Detailed Engineering Design) image sources for the Bukit Sulap Bridge project, which were obtained from the PUPR Department of Lubuklinggau City. The modelling carried out is in the form of steel frames, bracing, girder beams and bridge connections.

ПЕРСПЕКТИВЫ ПРИМЕНЕНИЯ НАКОПИТЕЛЕЙ ЭЛЕКТРОЭНЕРГИИ В ЭНЕРГЕТИЧЕСКИХ СИСТЕМАХ

This paper explores the possibility of using different types of electric power storage devices in energy systems. A comparative analysis of such types of storage devices as: electrochemical, electrical, electromagnetic, mechanical. The properties of lead-acid, nickel-cadmium, sodium-sulfur, lithium-ion batteries, supercapacitors, superconducting magnets, kinetic storage devices are analyzed with the identification of advantages and disadvantages of their use; the fields of their application are considered. The possibility of integrating storage devices with renewable energy sources is being considered. The analysis of the averaged load schedules for the winter and summer periods is performed; the feasibility of using the drive to smooth out the peaks of the consumption load schedules is justified. A schematic solution for connecting an electric power storage device with a control system for a medium-voltage power supply network is proposed. The connection of the drive in such a system is provided on the 0.4 kV side using converter devices. The using of an AC-DC converter with a control system in such a system regulates the flows of active power in order to perform a two-way energy conversion in the case of energy accumulation by the storage device and energy return to the network.

Probabilistic Safe WCET Estimation for Weakly Hard Real-time Systems at Design Stages

Weakly hard real-time systems can, to some degree, tolerate deadline misses, but their schedulability still needs to be analyzed to ensure their quality of service. Such analysis usually occurs at early design stages to provide implementation guidelines to engineers so they can make better design decisions. Estimating worst-case execution times (WCET) is a key input to schedulability analysis. However, early on during system design, estimating WCET values is challenging, and engineers usually determine them as plausible ranges based on their domain knowledge. Our approach aims at finding restricted, safe WCET sub-ranges given a set of ranges initially estimated by experts in the context of weakly hard real-time systems. To this end, we leverage (1) multi-objective search aiming at maximizing the violation of weakly hard constraints to find worst-case scheduling scenarios and (2) polynomial logistic regression to infer safe WCET ranges with a probabilistic interpretation. We evaluated our approach by applying it to an industrial system in the satellite domain and several realistic synthetic systems. The results indicate that our approach significantly outperforms a baseline relying on random search without learning and estimates safe WCET ranges with a high degree of confidence in practical time (< 23 h).

Supplemental Material for Confirmatory Factor Analysis of the 12-Item World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2.0) Within the Clubhouse Model of Psychosocial Rehabilitation for Serious Mental Illness

Supplemental Material for Confirmatory Factor Analysis of the 12-Item World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2.0) Within the Clubhouse Model of Psychosocial Rehabilitation for Serious Mental Illness

LAG-based schedulability analysis for preemptive global EDF scheduling with dynamic cache allocation

In recent years, the maturation of modern multicore processor technology and its increasing adoption in critical industrial domains have posed significant challenges for real-time systems, primarily due to contention for shared cache resources and the resulting uncertainty. To address this issue, contemporary processors employ cache partitioning techniques, enhancing temporal predictability by isolating cache access among processor cores. However, this isolation technique may lead to real-time tasks missing their deadlines due to an insufficient number of cache partitions. Consequently, this paper investigates the schedulability of preemptive global Earliest Deadline First (EDF) real-time scheduling algorithms that support dynamic cache allocation. We propose an innovative LAG-based schedulability analysis method for these algorithms and present a utilization-based schedulability condition that reduces analysis time complexity while improving analysis accuracy. Building upon this foundation, and incorporating task characteristics into our analysis, this paper further introduces an optimization technique aimed at minimizing the pessimism inherent in the schedulability test. Lastly, the performance and efficiency of the proposed schedulability determination method are validated through simulation experiments with randomly generated tasks.

Mixed-Trust Computing: Safe and Secure Real-Time Systems

Verifying complex Cyber-Physical Systems (CPS) is increasingly important given the push to deploy safety-critical autonomous features. Unfortunately, traditional verification methods do not scale to the complexity of these systems and do not provide systematic methods to protect verified properties when not all the components can be verified. To address these challenges, this article proposes a real-time mixed-trust computing framework that combines verification and protection. The framework introduces a new task model, where an application task can have both an untrusted and a trusted part. The untrusted part allows complex computations supported by a full OS with a real-time scheduler running in a VM hosted by a trusted hypervisor. The trusted part is executed by another scheduler within the hypervisor and is thus protected from the untrusted part. If the untrusted part fails to finish by a specific time, the trusted part is activated to preserve safety (e.g., prevent a crash) including its timing guarantees. This framework is the first allowing the use of untrusted components for CPS critical functions while preserving logical and timing guarantees, even in the presence of malicious attackers. We present the framework its schedulability analysis and the coordination protocol between the trusted and untrusted parts. Our implementation on a Raspberry Pi 3 is also discussed along with experiments showing the behavior of the system under failures of untrusted components, and a drone application to demonstrate its practicality.

Statistical analysis of the key scheduling of the new lightweight block cipher

This research paper is aimed at studying the generation of round keys (GRK) of the lightweight block cipher (LBC), which provides an optimal balance between security, performance, and minimal costs in internet of things (IoT). For comparative analysis, the GRK of the well-known PRESENT algorithm was studied. A number of studies have been carried out to assess the cryptographic strength of encryption algorithms, however, less attention has been paid to the assessment of the reliability of GRK algorithms, which can lead to a possible weakening of a cryptosystem. A trusted GRK should issue random and independent round keys regardless of the secret key. The experiments were carried out with secret keys of low and high density, as well as random numbers. The obtained results show that the GRK of the LBC algorithm generates random round keys that successfully pass tests of the National Institute of Standards and Technology (NIST) for randomness.

Period Cycle Optimization of Integrated Energy Systems with Long-Term Scheduling Consideration

The economy and energy saving effects of integrated energy system dispatch plans are influenced by the coupling of different energy devices. In order to consider the impact of changes in equipment load rates on the optimization and scheduling of the system under long-term operation, a method for energy and component cycle optimization considering energy device capacity and load has been proposed. By improving the initial parameters of the components, energy economic parameters, and operational optimization parameters, the system is subjected to long-term scheduling and multi-cycle operational optimization analysis to evaluate the energy saving and emission reduction potential as well as the economic feasibility of the system. Finally, through numerical analysis, the effectiveness of this optimization approach in achieving energy savings, emission reductions, and cost benefits for the system is validated. Furthermore, compared to existing optimization methods, this approach also assesses the economic feasibility of the system. The case study resulted in a pre-tax IRR of 23.14% and a pre-tax NPV of 66.38 million. It is inferred that the system could generate profits over a 10-year operation period, thereby offering a more rational and cost-effective scheduling scheme for the integrated energy system.

Analisa Penjadwalan Proyek Rentang Headworks And Cipelang Main Canal Upgrading Works Rentang Irrigation Modernization Project (RIMP) Dengan Metode Diagram Pareto Kecamatan Jatitujuh Kabupaten Majalengka

Project scheduling has an important role in ensuring smooth project implementation and achieving the desired project objectives. In this context, the project scheduling analysis of the Rentang Headworks and Cipelang Main Canal Upgrading Works Rentang Irrigation Modernization Project (RIMP) in Jatitujuh District, Majalengka Regency is important to ensure the efficiency and effectiveness of project implementation. The Pareto diagram method is used in this analysis to identify and address key issues that may arise during project implementation. This research aims to improve the scheduling of the RIMP project by using the Pareto diagram method to increase the efficiency of time, cost, and resources. The results of the analysis show that the critical factors affecting the scheduling of the RIMP project are delays in material procurement, lack of coordination between related parties, and changes in demand from stakeholders. In the Pareto diagram, these problems are placed on the Y-axis and ranked in order of importance. After identifying the main problems, specific improvement measures were proposed to address each problem. Measures such as improving material procurement, enhancing coordination between relevant parties, and devising a more structured change request mechanism can help reduce delays and improve project scheduling efficiency. Using the Pareto diagram method, this RIMP project scheduling analysis provides a clear view of the key issues affecting project execution. The results of this analysis can be used by the project team to make better decisions in project planning and execution, with the hope of improving the efficiency and success of the project.

Elotuzumab: Empiric analysis of dexamethasone administration schedule.

Elotuzumab in combination with dexamethasone and immunomodulating agents (IMiDs) lenalidomide or pomalidomide is 2nd to 4th line therapy for multiple myeloma. The labelled dosage of dexamethasone for use in conjunction with elotuzumab and IMiDs splits the dexamethasone dose into two administrations, one oral and one intravenous, on the days of each elotuzumab infusion. Administration of split dose dexamethasone on days of elotuzumab administration is based on the registration trials submitted for drug approval and was intended to ensure standard well-timed immunotherapy premedication using pharmacologically equivalent dexamethasone doses for both study arms. Administration of dexamethasone in the manner delineated by the elotuzumab product label adds complexity to the delivery of care. This commentary provides an empirical assessment of established medication safety and effectiveness which supports administration of dexamethasone standard intermittent dose instead of the split dose approach delineated on elotuzumab package insert. Simplification of regimen administration improves medication adherence, reduces the risk of inadvertent omission or duplication of medication therapy, and improves the workflow required for delivery of care.