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In the domain of operations design and analysis, the ability to see a 3D animation of processes that have been simulated allows for three very important things: 1) The developer of a simulation model can ascertain that there are no errors in the coding (Verification); 2) The experts, field personnel, and decision makers can discover differences between the way they understand the operation and the way the model developer understands it (Validation); and 3) A model can be communicated effectively which, coupled with verification and validation, makes it "credible" and thus used in making decisions. In the case of simulated construction operations, the existent body of knowledge and understanding did not generally permit modeled processes to be accurately visualized in 3D. The purpose of this research was to remedy this situation and find methods of describing animated 3D worlds that show how construction operations modeled using Discrete-Event Simulation were/can be carried out, using simple text statements and references to 3D CAD drawings. The fundamental question the work addressed was how to achieve accurate, dynamic, smooth, and continuous 3D animation of arbitrarily-complex simulated construction processes, based on meager pieces of operational information that can only be communicated when discrete events occur in simulation runs. The end result of this effort is VITASCOPE, an acronym for VIsualizaTion of Simulated Construction OPErations. VITASCOPE is a simple, parametric-text animation description language that is meant to be written out by end-user programmable software such as discrete-event simulation tools. Sequential instructions written in this language allow a computer to create a 3D virtual world that is accurate in time, space, and appearance; and that shows people, machines, and materials interacting as they build constructed facilities. / Ph. D.

A pavement investment and management process has a dynamic structure with cause and effect. Better investment decisions for maintenance will increase the condition of the flexible pavement and will end up with a better level of service. Therefore, better investments decisions on pavement maintenance will increase the economic growth and global competition for the area. However, improper allocation of money and resources would end up with further deteriorations of the facilities. So asset management encourages highway maintenance managers to spend their scarce budget for the maintenance that is really needed. A well-developed pavement management simulation model will allow highway maintenance managers to consider the impact of choosing one maintenance policy alternative versus another through what-if analysis and having informed decisions. Discrete event simulation (DES) is an alternative method of analysis that offers numerous benefits in pavement management. Unlike the models currently in use, a decision support model created by utilizing the DES technique would allow fractionalizing the pavement in smaller proportions and simulating the policies on these smaller segments. Thus, users would see how their decisions would affect these specific segments in the highway network over a period of time. Furthermore, DES technique would better model the multiple resource requirements and dynamic complexity of pavement maintenance processes. The purpose for this research is to create a decision support tool utilizing discrete event simulation technique where the highway maintenance managers can foresee the outcomes of their what-if scenarios on the specific segments and whole of the highway network evaluated. Thus, can be used for both project and network level decision support. The simulation can also be used as a guiding tool on when, where and why resources are needed on needs basis. This research relies on the budget allocation results from the linear optimization model (LOM). This model is a tool that creates the optimized budget allocation scheme for a network fitting to a determined scenario. Thus by integrating the LOM and the DES model, the maintenance managers can acquire an optimized budget allocation for their district and evaluate the results in both network and project selection level. Maintenance managers can obtain the best budget allocation plan without performing the repetitive trial and error approach like the previous decision support tools. There is a vast amount data in many varieties gathered as results from the simulation model. This fact alone demonstrates how powerful the discrete event simulation model is. By the nature of this simulation technique, the resources (highway segments, annual budget) can be traced throughout the simulation and this trait allows the design of the project selection level decision support system. By examining these reports, the maintenance managers can better observe how the scenarios evolve. Thus this tool helps the maintenance managers to have better decisions on the project selection level. The discrete event simulation model established in this research carries the project selection level pavement management from a position where maintenance managers should solely depend on their engineering judgment and experience to a position where maintenance managers can have more effective and justified plans since they can foresee the results of these decisions on the segments that are forming the network. This simulation engine is created with the discrete event simulation language called STROBOSCOPE. The model consists of two parts which work like a lock and key mechanism. The first part of the model is the data feeding mechanism where information from any network is loaded. The second part is the generic engine which can evaluate any road network data it is fed. The purpose of segregating these two components of the model is to allow the user to evaluate any network regardless of length, number of segments or the location. / Master of Science

The construction industry is one of the largest emitters of greenhouse gases and health-related pollutants. Monitoring and benchmarking emissions will provide practitioners with information to assess environmental impacts and improve the sustainability of construction. This research focuses on real-time measurement of emissions from non-road construction equipment and development of a monitoring-benchmarking tool for comparison of expected vs. actual emissions. First, exhaust emissions were measured using a Portable Emission Measurement System (PEMS) during the operation of 18 pieces of construction equipment at actual job sites. Second-by-second emission rates and emission factors for carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons were calculated for all equipment. Results were compared to those of other commonly used emission estimation models. Significant differences in emission factors associated with different activities were not observed, except for idling and hauling. Moreover, emission rates were up to 200 times lower than the values estimated using EPA and California Air Resources Board (CARB) guidelines. Second, the resulting database of emissions was used in an automated, real-time environmental assessment system. Based on videos of actual construction activities, this system enabled real-time action recognition of construction operations. From the resulting time-series of activities, emissions were estimated for each piece of equipment and differed by only 2% from those estimated by manual action recognition. Third, the actual emissions were compared to estimated ones using discrete event simulation, a computational model of construction activities. Actual emissions were 28% to 144% of those estimated by manual action recognition. Results of this research will aid practitioners in implementing strategies to measure, monitor, benchmark, and possibly reduce air pollutant emissions stemming from construction. / Master of Science

As SystemC gains popularity as a System Level Design Language (SLDL) for System-On-Chip (SOC) designs, heterogeneous modelling and efficient simulation become increasingly important. The key in making an SLDL heterogeneous is the facility to express different Models Of Computation (MOC). Currently, all SystemC models employ a Discrete-Event simulation kernel making it difficult to express most MOCs without specific designer guidelines. This often makes it unnatural to express different MOCs in SystemC. For the simulation framework, this sometimes results in unnecessary delta cycles for models away from the Discrete-Event MOC, hindering the simulation performance of the model. Our goal is to extend SystemC's simulation framework to allow for better modelling expressiveness and efficiency for the Synchronous Data Flow (SDF) MOC. The SDF MOC follows a paradigm where the production and consumption rates of data by a function block are known a priori. These systems are common in Digital Signal Processing applications where relative sample rates are specified for every component. Knowledge of these rates enables the use of static scheduling. When compared to dynamic scheduling of SDF models, we experience a noticeable improvement in simulation efficiency. We implement an extension to the SystemC kernel that exploits such static scheduling for SDF models and propose designer style guidelines for modelers to use this extension. The modelling paradigm becomes more natural to SDF which results to better simulation efficiency. We will distribute our implementation to the SystemC community to demonstrate that SystemC can be a heterogeneous SLDL. / Master of Science

Electronic design automation (EDA) tools play a central role in bridging the productivity gap for designing complex hardware systems. However, with an increase in the size and complexity of today's design requirements, current methodologies and EDA tools are unable to effectively mitigate the further widening of productivity gap. It is estimated that testing and verification takes 2/3rd of the total development time of complex hardware systems. Functional simulation forms the main stay of testing and verification process and is the most widely used technique for testing and verification. Most of the simulation algorithms and their implementations are designed for uniprocessor systems that cannot easily leverage the parallelism in multi-core and GPU platforms. For example, logic simulation often uses levelized sequential algorithms, whereas the discrete-event simulation frameworks for Verilog, VHDL and SystemC employ concurrency in the form of multi-threading to given an illusion of the inherent parallelism present in circuits. However, the discrete-event model of computation requires a global notion of an event-queue, which makes improving its simulation performance via parallelization even more challenging. This work investigates automatic parallelization of simulation algorithms used to simulate hardware models. In particular, we focus on parallelizing the simulation of hardware designs described at the RTL using SystemC/HDL with examples to clearly describe the parallelization. Even though multi-cores and GPUs other parallelism, efficiently exploiting this parallelism with their programming models is not straightforward. To overcome this, we also focus our research on building intelligent translators to map simulation applications onto multi-cores and GPUs such that the complexity of the low-level programming models is hidden from the designers. / Master of Science

In a distributed real-time system there is often a need for time synchronization of the network’s nodes. In the telecommunications industry, this is exemplified by the implementation of 5G New Radio (NR) that uses Time Devision Duplexing (TDD) communication between the user equipment and base station in a Radio Access Network (RAN). To enable communication there exists a strict requirement of no larger error than 3 μs set by the 3rd Generation PartnershipProject (3GPP). Originally made to synchronize lab equipment, the Precision Time Protocol (PTP) has been adapted for the telecom industry’s needs. The Institute of Electrical and Electronics Engineers (IEEE) in the 1588a-2023 amendment demonstrates how PTP will not create the ideal timeTransmitter-timeReceiver hierarchy in two case studies. To address these problems a modification of the Best TimeTransmitter Clock Algorithm (BTCA) is necessary. The amendment introduces the Enhanced Accuracy Metrics TLV as an optional feature. This featureenables each clock to gain knowledge about the inaccuracy of time from its neighboring clocks.The standard BTCA does not utilize the information from this new feature in its decision mechanism. This thesis presents four new alternate BTCA and to evaluate the algorithms a network simulator was built focusing on the timeTransmitter-timeReceiver hierarchy. The simulator is proven to be useful and in a case study, the four new BTCAs are evaluated where two of them solve the issues mentioned in the 1588a-2023 amendment.

In the coming decades, many automotive industries will undergo changes where the electrification of vehicles will play a significant role. In order for a manufacturing company to be able to compete in the market, constant adaptation is needed to maintain competitiveness. To make companies more efficient, tools as Lean production is used together with several digital technologies to maintain a competitiveness and facilitate possible changes. Simulation can be used to control and develop future production and answer important questions about about future challenges.The purpose of this study is to investigate, through discrete event simulation, the needs and conditions that a scenario with 50% conventional and 50% electric driveunits will introduce to Scania’s transmission production. The purpose was partially fulfilled through a preliminary study to provide a basis for the upcoming simulation models. This preliminary study identified three critical buffers, essential for future production planning. Therefore, three simulation models were established, focusing on the total number of buffer slots. The result of this study presents three proposals for the number of slots for each buffer, as well as the number of stations for the testing and repair of the electric units. Given that a high volume of products alters the need for space requirements, it was crucial to describe the capacity of these buffers and the potential of their stations. To fully leverage this study and the three simulation models, a more further and detailed data collection on several production processes is recommended.

The process of enrolling and completing the courses needed to earn an undergraduate degree involves complex interactions between individual students and institutional policies and procedures, especially because student and institutional priorities do not always align. Traditional social and behavioral statistical methods are ineffective for modeling these interactions. Simulation and algorithm-based modeling approaches have been underutilized in higher education, but their adaptability can accommodate the complexity of the degree attainment process. The purpose of this research was to design, develop, validate, and apply a multi-method Course Enrollment Simulation Model (CESM), which mirrored the process of college students enrolling in courses required for a specific undergraduate degree program. Simulated output from the model included graduation outcomes, like six-year graduation rates and average terms for students to obtain the degree, which are metrics commonly tracked by institutions of higher education. As proof of concept, data from a Fall 2015 student cohort and graduation requirements for an undergraduate computer science program at a large public university were used to create and test the CESM. The model integrated elements of discrete event simulation, agent-based modeling, and microsimulation methods into one architecture. Monte Carlo experiments were used to assess the validity of the model, which was more accurate than comparable inferential statistics. Finally, the CESM was used to evaluate summer enrollment policy options intended to improve graduation outcomes in a computer science program, finding that the effectiveness of the proposed policies depended on student factors as well as course requirements of the degree program. This dissertation is formatted as a collection of three studies, each organized into a publishable manuscript.