CYBER physical systems, COMPUTER systems, CYBERNETICS, COMPUTER simulation, and SYSTEMS design
Sensors and effectors of all sorts are becoming more and more integrated in human everyday lives. Systems built on top of these sensors/effectors adding a cybernetic component in order to assist humans in their everyday life are called Cyber-Physical Systems. Such systems may be difficult to analyze and design, as they are composed of numerous interacting entities immerged in a dynamic and partially predictable environment. The goal of this paper is to propose a methodological approach based upon Multi-Agent Systems that has two main advantages. First it allows the decomposition of CPS structural and behavioral complexity and, second, it enables a prototyping by simulation approach that eases system validation. [ABSTRACT FROM AUTHOR]
RAPID prototyping, MAXILLOFACIAL surgery, ZYGOMATIC fractures, OSTEOTOMY, COMPUTER simulation, TOMOGRAPHY, POSTOPERATIVE care, and OPERATIVE surgery
Abstract: Introduction: The management of post-traumatic deformity in the midface region poses challenges for the maxillofacial surgeon. Ensuring symmetry after zygomatic osteotomy can be difficult and precise positioning of the osteotomised bony fragments requires careful treatment planning. It may be necessary to use a coronal flap to allow the surgeon to compare the contralateral zygomatic bone to allow symmetrical reduction. The authors present a new technique for the positioning of osteotomised zygomatic bones using a combination of computer assisted surgical simulation and rapid prototyping. Method: A patient presented to our unit with a post-traumatic zygomatic deformity. Using surgical simulation software the displaced zygomatic bone was osteotomised and placed in the idéal position on a three-dimensional computed tomography scan (3D CT). The position was determined by reference to the contralateral zygoma. In addition the repositioning of the soft tissues was simulated. A surgical guide which allowed intraoperative positioning of the osteotomised zygoma was manufactured by a rapid prototyping process. Use of the guide allowed a minimally invasive approach to the affected zygoma. The post-operative results were compared to the predicted outcome. Results: The post-operative appearance was satisfactory and corresponded well with the predicted result. There was a significant reduction in operative time compared to the previous management of similar cases. [Copyright &y& Elsevier]
PROTOTYPES, END users (Information technology), COMPUTER input-output equipment, COMPUTER simulation, COMPUTER algorithms, and SIMULATED annealing
Abstract: We introduce Sketch Arm, a brand new tool for custom closets rapid prototyping that allows end users to sketch a completely customized design proposal regardless of their technological training. Supported in current multi-touch hardware technology, the application is conceived as a highly interactive system, and it can also assist the user with the prototype creation tasks by autonomously generating desirable layouts. Incorporating a simulated annealing algorithm enables this automatic generation of layouts by optimizing the closet inner space. Throughout this paper, we present the main features and capabilities of Sketch Arm. We demonstrate that our system is able to synthesize suitable closet layouts, creating several design proposals for different user profiles. [Copyright &y& Elsevier]
Deppe, M., Zanella, M., Robrecht, M., and Hardt, W.
Journal of Systems & Software. Mar2004, Vol. 70 Issue 3, p263. 12p.
PROTOTYPES, AUTOMOBILE industry, REAL-time control, and COMPUTER simulation
Rapid prototyping of complex systems embedded in even more complex environments raises the need for a layered design approach. Our example is a mechatronic design taken from the automotive industry and illustrates the rapid-prototyping procedure of real-time-critical control laws. The approach is based on an object-oriented structuring allowing not only central control units but also distributed control units as needed by today’s designs. The implementation of control laws is a hardware-in-the-loop simulation, refined in steps and reducing the simulation part at every one of these. On the lower level, common platforms, such as FPGAs, microcontrollers or specialized platforms, can be instantiated. [Copyright &y& Elsevier]
Hansel, David, Cleaveland, Rance, and Smolka, Scott A.
Journal of Systems & Software. Mar2004, Vol. 70 Issue 3, p275. 24p.
COMPUTER operating systems, C++, REAL-time computing, and COMPUTER simulation
We present vpl2cxx, a translator that automatically generates efficient, fully distributed C++ code from high-level system models specified in the mathematically well-founded VPL design language. As the Concurrency Workbench of the New Century (CWB-NC) verification tool includes a front-end for VPL, designers may use the full range of automatic verification and simulation checks provided by this tool on their VPL system designs before invoking the translator, thereby generating distributed prototypes from validated specifications. Besides being fully distributed, the code generated by vpl2cxx is highly readable and portable to a host of execution environments and real-time operating systems (RTOSes). This is achieved by encapsulating all generated code dealing with low-level interprocess communication issues in a library for synchronous communication, which in turn is built upon the adaptive communication environment (ACE) client-server network programming interface. Finally, example applications show that the performance of the generated code is very good, especially for prototyping purposes. We discuss two such examples, including the RETHER real-time Ethernet protocol for voice and video applications. [Copyright &y& Elsevier]
BONE fractures, RAPID prototyping, SKULL injuries, COMPUTED tomography, and ORTHOPEDIC implants
Background This study evaluated the accuracy of blow out fracture reduction using 3D-printed rapid prototyping (RP) skull modeling. Patients and methods Retrospective review was performed for 82 patients who underwent post-traumatic orbital wall fracture reduction between 2012 and 2014. Patients were divided into two groups according to the use of 3D-printed RP skull model reproduced by mirroring technique, onto which a titanium mesh was anatomically molded. Using computed tomographic scans, the areas of pre- and post-operative orbital wall defect, the layout angles of the titanium mesh, and the gap lengths between the implant and fracture margin were compared between the two groups. Results Of the 82 patients identified, 46 and 36 were diagnosed with medial and inferior orbital wall fractures, respectively. Bone defect area of the RP group was significantly reduced in comparison with that of the conventional group (8.03 ± 3.5% versus 18.7 ± 15.41% for medial wall fractures, 7.14 ± 5.74% versus 12.8 ± 4.92% for inferior wall fractures, respectively, p < 0.01). Satisfactory results were achieved regarding the layout angles and the gap lengths, presenting significantly reduced values in the RP group compared to that in the conventional group ( p < 0.01). Conclusions More accurate restoration of traumatic orbital wall fractures can be achieved using patient-specific 3D-printed RP skull models. [ABSTRACT FROM AUTHOR]
The original purpose of the study is to solve the inverse problem of synthesis of freeform optical elements. This article describes a numerical approach for synthesis of freeform refracting surfaces forming a line radiation pattern. [ABSTRACT FROM AUTHOR]
Computer simulation has become an indispensable tool in engineering design as they allow an accurate evaluation of the system performance. This is critical in order to carry out the design process in a reliable manner without costly prototyping and physical measurements. However, high-fidelity computer simulations are computationally expensive. This turns to be a fundamental bottleneck when it comes to design automation using numerical optimization techniques. In particular, direct optimization of simulation models, typically, requires a large number of model evaluations, which may be impractical or even infeasible in a reasonable timeframe. Possibly the most promising approach to alleviate this difficulty is surrogate-based optimization (SBO), where direct optimization of expensive models is replaced by an iterative enhancement and re-optimization of fast surrogate models. While a large variety of surrogate modeling and optimization are available, the methods exploiting the so-called physics-based surrogates seem to be the most efficient ones because the knowledge about the system of interest embedded in the underlying (often simulation-based) low-fidelity model ensures good generalization of the surrogate and a rapid convergence of the SBO algorithm. In this paper, we review a specific technique of this class, that is, the adaptive response correction (ARC). We discuss the formulation of the method, its limitations and generalizations, as well as illustrate its application for solving problems in various areas, including microwave engineering, antenna design, and aerodynamic shape optimization. [ABSTRACT FROM AUTHOR]
COMPUTER simulation, STRUCTURAL models, FINITE element method, METAMATERIALS, and THREE-dimensional modeling (Computer graphics)
The experiments and computer research on the issue of metamaterials [6-9,11,14] allow a dedicated parts or even whole devices designing using 3D CAD technology and Finite Element Methods. Research and their effects aim at replacing the mechanisms by means of elements perform by additive technology with different internal geometry in terms of dimensions and shapes, while maintaining identical dimensions in such a way that the desired abbreviated motion. In order to do that the adequate computer model [15-24] using for fast and effective prototyping is desired. The initial steps to achieve this aim is shown in this work. [ABSTRACT FROM AUTHOR]
The prototyping and the development of computational codes for biological models, in terms of reliability, efficient and portable building blocks allow to simulate real cerebral behaviours and to validate theories and experiments. A critical issue is the tuning of a model by means of several numerical simulations with the aim to reproduce real scenarios. This requires a huge amount of computational resources to assess the impact of parameters that influence the neuronal response. In this paper, we describe how parallel tools are adopted to simulate the so- called depolarization block of a CA1 pyramidal cell of hippocampus. Here, the high performance computing techniques are adopted in order to achieve a more efficient model simulation. Finally, we analyse the performance of this neural model, investigating the scalability and benefits on multi-core and on parallel and distributed architectures. [ABSTRACT FROM AUTHOR]
WIRELESS sensor networks, COMPUTER simulation, COMPUTATIONAL complexity, DATA analysis, DATA packeting, and EMPIRICAL research
Simulation of wireless sensor networks with very large number of motes poses significant challenges with respect to computational complexity. Application level code prototyping with reasonable accuracy and fidelity can however be accomplished through simulation that models only the effects of the wireless and distributed computations which materialize as delay and drop for the messages being exchanged among the motes. This study pursues that idea of empirical modelling of delay and drop and employs such a model to affect the reception times of wirelessly communicated messages. The delay and drop is therefore, modelled as random variables with probability distributions empirically approximated based on the data reported in the literature. The paper concludes with a case study that employs the proposed empirical delay and drop models for multilayer perceptron neural networks distributed across a wireless sensor network for a classification task on the Isolet dataset. [ABSTRACT FROM AUTHOR]
Sanchez, M. Isabel, Gramaglia, Marco, Bernardos, Carlos J., de la Oliva, Antonio, and Calderon, Maria
Ad Hoc Networks; Aug2014, Vol. 19, p9-27, 19p
COMPUTER network protocols, VEHICULAR ad hoc networks, MOBILE communication systems, COMPUTER simulation, and MACHINE learning
Abstract: Research on vehicular communications has been quite extensive over the past few decades. Most of the initial studies were theoretical and research has just recently moved to more experimental works. Conducting real field operational tests is extremely challenging due to the number of vehicles required, the lack of control over the environment and the cost of the necessary equipment and personnel. However, simulation tools may not reflect properly the highly dynamic and complex characteristics of the vehicular scenario. This article explores why practical research in the field of vehicular communications is so demanding, by reporting on our experience in prototyping and experimentally evaluating VARON. Published in 2008, VARON is a multi-hop wireless vehicular communication protocol which was already validated via extensive simulations. In this work, we have fully implemented it, first on a lab-based environment, and then in a real-life testbed. This long and exhausting process has shown that some common assumptions do not necessarily hold when evaluated under real situations, as well as taught us valuable lessons on how to design and conduct experiments with real vehicles. We believe that the experience and lessons learned during this process do not only apply to VARON, but also to other multi-hop wireless vehicular communication solutions, and that therefore these lessons are helpful for other researchers willing to validate their protocols in a real scenario. [Copyright &y& Elsevier]
Pervasive & Mobile Computing; Jun2014, Vol. 12, p139-159, 21p
INTELLIGENT buildings, APPLICATION software, UNCERTAINTY (Information theory), INFORMATION theory, COMPUTER simulation, and COMPUTER visualization
Abstract: Smart Building Applications (SBAs) adapt their behaviour in response to context information generated by sensors present in the smart building. SBA developers must account for uncertainty in the accuracy of context information resulting from imperfection in the sensing technology and potentially complex interactions between the sensed phenomenon, the sensor and the physical environment. To address this challenge, context simulators which generate simulated context information have been developed. A number of key challenges must be addressed before such a simulation-based SBA prototyping approach can become widely used. First, any context simulator must be flexible in its approach to simulating context so that it supports evaluating different mixes of SBAs using a selection of methods most suitable to the evaluation task at hand. Second, the context simulator must support simulating uncertainty in context as uncertainty can cause an SBA to function incorrectly. Finally, the process of setting up a simulation should be efficient in use, satisfying to the developer and also, be effective in correctly evaluating the SBA behaviour. This paper presents the SimCon model which addresses these challenges by supporting simulation of context, in particular location context, with configurable levels of uncertainty for evaluating SBAs using visualisation. The SimCon model has been implemented in a simulation, configuration and visualisation tool set which has undergone a number of evaluations with SBA developers to determine and improve its level of usability, the most recent of which is presented here. [Copyright &y& Elsevier]
ENERGY consumption, COMPUTATIONAL fluid dynamics, COMPUTER simulation, INTERNAL combustion engines, and COGENERATORS
Cogeneration is commonly recognized as one of the most effective solutions to achieve the increasingly stringent reduction in primary energy consumption and greenhouse emissions. This characteristic led to the adoption of specific directives promoting this technique. In addition, a strategic role in power reliability is recognized to distributed generation. The study and prototyping of cogeneration plants, therefore, has involved many research centres. This paper deals with energetic aspects of CHP referring to the study of a 15 kW micro-CHP plant based on a LPG reciprocating engine designed, built and grid connected. The plant consists of a heat recovery system characterized by a single water circuit recovering heat from exhaust gases, from engine coolant and from the energy radiated by the engine within the shell hosting the plant. Some tests were carried out at whole open throttle and the experimental data were collected. However it was needed to perform a 1D thermo-fluid dynamics simulation of the engine to completely characterize the micro-CHP. As the heat actually recovered depends on the user's thermal load, particularly from the required temperature's level, a comparison of the results for six types of users were performed: residential, hospital, office, commercial, sports, hotel. Both Italian legislative indexes IRE and LT were evaluated, as defined by A.E.E.G resolution n. 42/02 and subsequent updates, as well as the plant's total Primary Energy Saving. [ABSTRACT FROM AUTHOR]
Pettigrew, Liam, Blomenhofer, Verena, Hubert, Stefan, Groß, Frauke, and Delgado, Antonio
Journal of Cleaner Production. Jan2015, Vol. 87, p583-593. 11p.
MANUFACTURING processes, MATHEMATICAL optimization, WATER use, BREWERY waste, COMPUTER simulation, and PETRI nets
The brewery industry is becoming increasingly aware of its water and energy usage due to stricter regulations, and environmental and economic incentives. An area where large improvements in water usage presents itself is the clean-in-place system. A significant portion of the total process water required in an industrial sized brewery is used during clean-in-place processes. Testing and optimisation of these industrial processes can be quickly and economically achieved using computer modelling and simulation tools. One such tool is the reference net, a subclass of object-oriented Petri nets. In order to predict the water usage and the potential for energy production from wastewater attributed to the clean-in-place plant in a brewery, the reference net formalism is used. Validation of the complete reference net system is undertaken using two sets of simulations, one set of simulations running an approximation of a standard brewery clean-in-place system and a second set implementing a fuzzy logic adaptive control for water reuse. The reference net is found to be a valid and efficient tool for quick prototyping of new and existing industrial sized brewery clean-in-place systems. [ABSTRACT FROM AUTHOR]