Large system simulation using Ada

Modeling of unstable pelvic fractures for 20 ° sagittally rotated pelvic displacement

Minimally invasive surgery (MIS) for hallux valgus (HV) has gained popularity. However, adopting this technique faces the challenges of a pronounced learning curve. This study aimed to address these challenges by developing and validating an innovative simulation model and training program, targeting enhanced proficiency in HV MIS. A training program and a high-fidelity simulation model for HV MIS were designed based on experts' recommendations. Four foot and ankle surgeons without experience in MIS formed the novice group and took the program that encompassed six-session instructional lessons, hands-on practice on simulated models, and immediate feedback. The program concluded with a cadaveric surgery. Four foot and ankle experienced MIS surgeons formed the expert group and underwent the same procedure with one simulated model. Participants underwent blind assessment, including Objective Structured Assessment of Technical Skills (OSATS), surgical time, and radiograph usage. Expert evaluation of the simulation model indicated high satisfaction with anatomical representation, handling properties, and utility as a training tool. The expert group consistently outperformed novices at the initial assessment across all outcomes, demonstrating OSATS scores of 24 points (range, 23 to 25) versus 15.5 (range, 12 to 17), median surgical time of 22.75 minutes (range, 12 to 27) versus 48.75 minutes (range, 38 to 60), and median radiograph usage of 70 (range, 53 to 102) versus 232.5 (range, 112 to 280). Novices exhibited a significant improvement in OSATS scores from the fifth session onward (P = 0.01), reaching the desired performance of 20 points. Performance at the final training with the simulated model did not differ from cadaveric surgery outcomes for all parameters. This study validated a simulation model and training program, allowing nonexperienced HV MIS foot and ankle surgeons to enhance their surgical proficiency and effectively complete a substantial portion of the learning curve at the fifth session, and this performance was successfully transferred to a cadaver model. III.

The article provides an overview of the possibilities of holographic 3D showcases as one of the methods of visualizing 3D content by recognizing individual objects in the image and transferring them as individual elements to a holographic 3D showcase. Depending on the types of simulation models, there is a need for visualization of the obtained results for their evaluation and testing, with the possibility of further improvement. The use of displays that transmit images on a plane does not make it possible to get a complete picture of the subject being studied. The use of holographic 3D showcases opens the possibility of working with simulated models even at the stage of their creation in software applications for 3D modeling or for creating simulated 3D models. This gives the developer the opportunity to speed up the adjustment of object parameters even at the stage of forming models according to the initial technical task. It should be noted that the holographic 3D showcase is most effective for working with objects that have a 1:1 ratio with a real industrial sample. This makes it possible to adjust the development and testing of the model, as well as to change or evaluate the effectiveness of the functionality and to change the operating parameters without creating a useful model. This technique significantly speeds up the time of model implementation from the design project to the realization of a physical object. The information technologies used in the work of holographic 3D showcases are based on the use of web technologies, which, due to the programming of js scripts and parameters of style tables, allows you to obtain optimal results with a minimum load on the working computer, which allows you to use the application on a computer in parallel with applications for developing simulation models. The ability to display elements of the work area on a holographic 3D showcase directly in the modeling process allows you to focus on details that are invisible on flat displays.

MP60-18 PCP-SMART STUDY AND PCRD INDEX: INTRODUCTION AND RESULTS OF A NOVEL MATHEMATICAL SIMULATION MODELING METHOD, DEVISED TO PREDICT THE OUTCOME OF PROSTATE BIOPSY.

Cost Effective Simulation Model for Laparoscopic Uretero-Ureterostomy

Simulation modelling lacks a rich body of literature on practices of modellers in the real world. We study the context and some generic practices of expert simulation modellers to discover how the context of modellers may affect the practice of modelling and simulation. The results highlight that simulation modellers develop their models under a variety of contexts and their practices may be affected by their context. The problem area, the scope and the breadth of a problem, simulation software and the size and complexity of the model are some of the contextual factors which may affect a modeller’s practices such as model development, documentation, maintenance and evaluation. For example, model maintenance is required only for large scale models developed for long term use. Similarly, varying level of documentation may be required depending on the client requirements and project needs. Our study is a valuable addition to the research investigating simulation practice in the real world.

The decision rules in simulation models of human behavior purport to describe decision-making behavior as it is and not as it should optimally be. Without the criterion of optimality to judge the appropriateness of a decision rule, simulation modelers must rely on empirical confirmation of the structure of their models. In models of small organizations, traditional social science methods may be used. But these methods are infeasible in models of larger systems such as industries or the macroeconomy. This paper shows how direct experiment can be used to confirm or disconfirm the decision rules in simulation models. Direct experiment uses interactive gaming in which people play a role in the system being modeled. Subjects play the game in an institutional context corresponding to that of the model to be tested, and are given the same information set, but are free to make decisions any way they wish. The behavior of subjects can then be directly compared against the behavior produced by the assumed decision rules of the model. Differences between experiments to test simulation models and experiments in psychology and economics are discussed. The decision rule for capital investment in a simple macroeconomic model is tested as an example of the experimental approach. The model considers interactions between the multiplier and accelerator, a well-known structure underlying popular theories of business fluctuations, but one which has not been tested experimentally. Through their investment decisions, subjects attempt to balance demand and supply over time. The results strongly support the decision rule of the original model. Both model and subjects produce dysfunctional oscillations. The behavior of the subjects is qualitatively and quantitatively similar to that of the original model. Explanations for the bounded rationality of the subjects' behavior are considered, and the correspondence of the experiment to reality is discussed. The results demonstrate the promise of experimental methods as a complementary approach to econometrics in testing simulation models.

In recent years there has been an increasing interest in simulation modelling to study, control, and manage software development processes. Despite this, little attention has been paid towards the simulation modelling process itself. We have developed a rapid simulation modelling process (RSMP) based on our study of experienced simulation modellers. This paper reports a set of controlled experiments to evaluate the usability and utility of the RSMP. The results from this show that the RSMP has proved to be a usable and useful approach for developing software process simulation models. The results show that the RSMP is likely to bring discipline to software process simulation modellers and improve the quality of the model they produce.

The dynamic memory manager (DMM) is a key element whose customization for a target application reports great benefits in terms of execution time, memory usage and energy consumption. Previous works presented algorithms to automatically obtain custom DMMs for a given application. Nevertheless, those approaches are based on grammatical evolution where the fitness is built as an aggregate objective function, which does not completely exploit the search space, returning the designer the DMM solution with best fitness. However, this approach may not find solutions that could fit in a concrete hardware platform due to a very low value of one of the objectives while the others remain high, which may represent a high fitness. In this work we present the first multi-objective optimization methodology applied to DMM optimization where the Pareto dominance is considered, thus providing the designer with a set of non-dominated DMM implementations on each optimization run. Our results show that the multi-objective optimization provides Pareto-optimal alternatives due to a better exploitation of the search space obtaining better hypervolume values than the aggregate objective function approach.

A dynamic memory management system has to take care of the allocation and deallocation of memory blocks in a software system. Real-time embedded systems add some more constraints to the design and the implementation of dynamic memory management systems if compared with the PC world. An increasing number of features are added to embedded mobile devices, however, resources like dynamic memory are limited. In addition, in real-time systems, real-time deadlines must be respected and allocations and deallocations must be done in due time. In this paper we present a case study on evaluating dynamic memory management in embedded real-time systems. We have used a scenario-based approach and used a simulation environment to evaluate the performance of different dynamic memory management systems. Our contribution is to present a practical approach, the tools and the rationales to evaluate dynamic memory management in embedded real-time systems.

This paper presents the development of a simulation model for high-voltage gallium nitride (GaN) high-electron-mobility transistors (HEMT) in a cascode structure. A method is proposed to accurately extract the device package parasitic inductance, which is of vital importance to better predict the high-frequency switching performance of the device. The simulation model is verified by a double-pulse tester, and the results match well both in terms of device switching waveform and switching energy. Based on the simulation model, an investigation of the package influence on the cascode GaN HEMT is presented, and several critical parasitic inductances are identified and verified. Finally, a detailed loss breakdown is made for a buck converter, including a comparison between hard switching and soft switching. The results indicate that the switching loss is a dominant part of the total loss in hard-switching conditions in MHz high-frequency range and below 8~10A operation current, therefore soft switching is preferred to achieve high-frequency and high-efficiency operation of the high-voltage GaN HEMT.

Discrete Event Simulation (DES) is a widely used technique in which the state of the simulator is updated by events happening at discrete points in time (hence the name). DES is used to model and analyze many kinds of systems, including computer architectures, communication networks, street traffic, and others. Parallel and Distributed Simulation (PADS) aims at improving the efficiency of DES by partitioning the simulation model across multiple processing elements, in order to enabling larger and/or more detailed studies to be carried out. The interest on PADS is increasing since the widespread availability of multicore processors and affordable high performance computing clusters. However, designing parallel simulation models requires considerable expertise, the result being that PADS techniques are not as widespread as they could be. In this paper we describe ErlangTW, a parallel simulation middleware based on the Time Warp synchronization protocol. ErlangTW is entirely written in Erlang, a concurrent, functional programming language specifically targeted at building distributed systems. We argue that writing parallel simulation models in Erlang is considerably easier than using conventional programming languages. Moreover, ErlangTW allows simulation models to be executed either on single-core, multicore and distributed computing architectures. We describe the design and prototype implementation of ErlangTW, and report some preliminary performance results on multicore and distributed architectures using the well known PHOLD benchmark.

The article is devoted to the issues of substantiation of design solutions in the field of water management and hydraulic engineering construction using simulated water management models. The problems of creating databases using various models of natural processes, including climate forecasting systems and a model of atmospheric dynamics, are touched upon. The list of tasks that are solved with the use of MIKE class models, capable on the one hand to solve the problems of modeling natural processes, on the other – to carry out simulation modeling of natural technical systems, including water management, is considered. Software packages can be used to develop rules for managing individual reservoirs and their cascades. It is noted that when creating water management systems, determining their parameters and mode of operation, it is advisable to develop simulation models for expert water management analysis. This allows you to evaluate the functionality of the systems and avoid signifi cant errors at more detailed stages of design and operation. As an example, the water management system of the Zapadny Manych, a tributary of the Don, is given. The problems of the object and the range of tasks to be investigated are formulated. The system functions due to the regular water supply of part of the Don and Kuban rivers flow to it. The transfer resources are spent on irrigation, hydropower and demineralization of Lake Manych Gudilo, which is a wetland of the Rostov region of international importance. In the work, the system is schematized and a hydrological and water management analysis of the development of irrigated lands and hydropower potential is carried out using simulation modeling of the water balance with optimization elements. The directions of further research on the water supply system of the Zapadny Manych River basin are formulated.

A software system can be called a safe-system with respect to memory, when it supports only strong-typing and it does not allow for the manual disposal of dynamic memory [2]. The first aspect guarantees that untyped, potentially dangerous operations are caught by the compiler or by run-time checks. The second issue is solved by the utilisation of an automatic memory reclamation scheme, i.e. a garbage collector.In this paper we argue that the careful choice of the programming language, along with an automatic memory reclamation scheme can optimise memory usage, while ensuring that many of the logical errors related to memory can be avoided.

Several different simulation techniques, such as discrete event simulation (DES), system dynamics (SD) and agent-based modelling (ABM), have been used to model complex construction systems such as construction processes and project management practices; however, these techniques do not take into account the subjective uncertainties that exist in many construction systems. Integrating fuzzy logic with simulation techniques enhances the capabilities of those simulation techniques, and the resultant fuzzy simulation models are then capable of handling subjective uncertainties in complex construction systems. The objectives of this chapter are to show how to integrate fuzzy logic and simulation techniques in construction modelling and to provide methodologies for the development of fuzzy simulation models in construction. In this chapter, an overview of simulation techniques that are used in construction is presented. Next, the advancements that have been made by integrating fuzzy logic and simulation techniques are introduced. Methodologies for developing fuzzy simulation models are then proposed. Finally, the process of selecting a suitable simulation technique for each particular aspect of construction modelling is discussed.