International Journal of Simulation and Process Modelling (34 papers in press)
A seawater RO desalination process driven by dynamic pressure of high-speed seawater droplets
by Hui Lu, Yi Xiang, Qingfen Ma, Mengnan Hao
Abstract: Seawater reverse osmosis (RO) desalination requires driving pressure of 5~8 MPa which is usually offered by the high-pressure pump, the standard device employed in the commercial application, but which presents a series of problems. To replace the high-pressure pump, a seawater RO desalination technique driven by the dynamic pressure of high-speed seawater droplets is proposed. By theoretical calculation and computational fluid dynamics (CFD) simulation, the required operating conditions for the acquisition of effective impacting seawater droplets were investigated. The results showed that the velocity of the seawater droplet should exceed 70 m/s to achieve the driving pressure of 5 MPa, and simultaneously the air flow-rate should exceed 70 m/s to act as the accelerating medium. The proper size of the accelerated droplet at different air flow-rates within the range of 70~100 m/s were determined considering not only the final velocity of the droplets but also their gravitational settling limitation. In addition, five structures of the RO membrane module were designed and tested, in which the ring-shaped and semicircle-shaped structure exhibited good performance with droplet trap rate greater than 90%. Furthermore, the energy balance of the whole system is analysed, and some constructive suggestions are provided to reduce the energy consumption.
Keywords: seawater desalination; RO technique; dynamic pressure; micro droplets.
Simulation-based trajectory tracking coordination of intelligent vehicle with explicit model prediction
by Rufei Xing, Xingyuan Xu, Peng Gong, Weidong Miao
Abstract: One of the main problems for an intelligent vehicle is to address its real-time ability to track the transverse trajectory under multiple constraints. Based on optimisation methodology, this paper proposes a novel algorithm design based on explicit MPC for trajectory tracking. It uses the MPT toolbox, and provides an offline fast solution. Based on the simulation on Simulink/Carsim simulator, it shows that the offline solving method has the same tracking performance as the online solving problem by YALMIP toolbox. The computation speed is significantly increased. This paper has provided a new approach for improving the computation speed of trajectory tracking problem in case of strong nonlinearity and multiple constraints.
Keywords: trajectory tracking; EMPC; vehicle modelling; fast solving.
Middleware for running and debugging Taverna workflows using RESTful web services
by Kasikrit Damkliang, Pichaya Tandayya
Abstract: Scientific workflows composed of independent distributed web services let a user easily orchestrate dataflows and processing tasks, and handle interoperations with ever more intricate workflows. Typically these integrated workflows are complex, tightly-coupled, and computational and data intensive, because of the workflow invocation management. One side effect is the increase in no-response states as unpredictable events and infrastructure inconsistencies interrupt invocations and cause failure, which are hard and heavy work to manually debug. We propose middleware for running and debugging integrated workflows called RDW using the Taverna Server invocation engine which helps the user to investigate complex tightly-coupled workflows. Two debugging modes, sequential and parallel, are provided for inspecting the sub-workflows of these integrated workflows. Also, interactions between the user and the server are orchestrated seamlessly by the RDW, which manages workflow invocations and provides running and debugging logs. The execution time of our RDW is slightly less than the standard Workbench, although the sequential and parallel RDW debugging modes have slightly different running times. RDW offers stable workflow invocation which can significantly reduce the total execution times. The middleware is freely available from our website, http://bioservices.sci.psu.ac.th.
Keywords: invocation management; debugging workflows; result inspection; sequential and parallel debugging; invocation request and handling; scientific workflows; RESTful service.
Staff scheduling in restaurants where hall staff and robots cooperate
by Takashi Tanizaki, Takeshi Shimmura, Nobutada Fujii, António Oliveira Nzinga René
Abstract: The number of companies introducing robots as part of their workforce has been increasing in recent years. One aim of such companies is to have robots perform low value-added work, and humans perform high value-added work. This objective also generally applies to the service industry. Increasing the number of repeat customers and improving profitability are required in the restaurant business. Furthermore, customer satisfaction (CS), employee satisfaction (ES) and management satisfaction (MS) must be simultaneously improved. However, these three indices are in a trade-off relationship. Based on the abovementioned background, this study proposes the modelling of the staff scheduling problem in restaurants, where hall staff and robots cooperate, as a set covering problem. The simulation results show that increasing the utilisation of robots for low value-added work and hall staff for high value-added work with customer contact contributes to improvements in CS, ES, and MS in restaurants.
Keywords: staff scheduling; set covering problem; customer satisfaction; employee satisfaction; management satisfaction.
Occupant counting modelling for intelligent buildings based on data from multiple WiFi sniffers
by Ping Wang, Zhenya Zhang, Qiansheng Fang, Huaqian Cao, Si Chen
Abstract: Space heating, ventilation and air conditioning (HVAC) systems in buildings usually operate in a centralised manner, which relies on building regulation maximum occupancy numbers for maintaining a proper comfort index. In many scenarios, rooms or zones are infrequently used, and may be unnecessarily heated or cooled. Knowing the occupancy information and precise number of occupants in each room or zone can create energy saving through intelligent control of HVAC systems. In this paper, a novel classification-based occupant counting method using multiple WiFi sniffers is proposed firstly to get a coarse estimation of occupancy. Then, to deal with the false negative problem, i.e., those occupants who do not carry a smartphone or the WiFi module is not enabled hence cannot be counted, a p-persistent frequent itemsets with 1-right-hand-side (RHS)-based occupant correction algorithm is further proposed to improve the occupant detection performance in terms of accuracy using association analysis. Finally, our proposed methods are validated through real experiments. Results show that our classification-based occupant detection method using multiple WiFi sniffers outperforms the 1-WiFi-sniffer-based method, and the association analysis based correction algorithm can improve the accuracy performance in that it can see the occupants in buildings that the naive WiFi-based occupant detection method cannot see, which makes it a viable approach to occupant estimation for intelligent buildings.
Keywords: occupant counting; classification; WiFi sniffers; association analysis; frequent itemsets.
Performance modelling and availability analysis of a milk pasteurising system using Petri nets formalism
by Narendra Kumar, P.C. Tewari, Anish Sachdeva
Abstract: The focus area of this work is integrating Reliability, Availability, and Maintainability (RAM) aspects into the conceptual process design of a real industrial system. Quantitative performance analysis has been carried out using a Petri Nets (PN) approach. In the present study, availability is considered as a performance measure which has been used as an indicator of the reliability and maintainability of the plant. The availability is considered in the process design stage for sorting different design alternatives. The proposed technique suggested provides a better way of understanding behaviour of a system under various operating conditions. It will also help practitioners in deciding on maintenance strategy so that operation and maintenance costs can be optimised. Stochastic Petri Nets (SPN) has been used to model the possible interactions among all active or parallel equipments in the system. Performance parameters have been evaluated using modelling and simulation software GRIF of Petri module.
Keywords: failure; RAM tools; Petri nets; performance modelling.
3D modelling and simulation of heat transfers in the building envelope for different local construction materials in the littoral areas of Cameroon
by Adeline Chugoua Njamen, Louis Monkam, Alexis Kemajou, Félix Junior Ngouem, Christian Leumassi Ngamaleu
Abstract: The building structure is a filter that controls the heat exchanges between the exterior and the interior of the building. It plays an important role for the thermal comfort of the residents and the energy consumption of the building. The objective of this work is to analyze the thermal behavior of the building structure in humid climate for various local building materials: wood, cinder block and clay brick. To achieve this, a numerical code was written in the MATLAB 2014a software to solve by the finite difference method implicit scheme, the three-dimensional heat transfer equation. The simulation of our dynamic model takes into account the convection on the external and internal surfaces as well as the diffusion in the material constituting the structure. The particularity of this study is that in addition to being a 3D model, it allows to appreciate the behavior in the thermal bridges and in the Geometric center indoor. After analysis, we recommended an envelope made of wood material in the littoral region.
Keywords: building envelope; three-dimensional modelling; thermal simulation; finite difference method; thermal bridges; indoor ambience.
An heuristic algorithm for fair strategic personnel assignment in continuous operation
by Eero Immonen, Ari Putkonen
Abstract: This article introduces an heuristic initialise-and-refine algorithm for fair strategic (long-term) personnel assignment in continuous operation. Here, continuous operation refers to stable, reoccurring parallel work processes, with known tasks and constant demand, an example of which is given by university tuition on a degree programme across many years. The proposed method attempts to address both the employees' competency-preference matching and the workload balancing aspects of fairness simultaneously, in situations where the task schedule across the parallel production lines is known beforehand. As an application, the proposed method is successfully used for optimising the module assignment of teachers in a Mechanical Engineering degree programme at a Finnish university.
Keywords: personnel assignment; strategic planning; competency matching; preference matching; workload balancing; heuristic algorithm.
Managing structural variability in agent-based models with feature coherence graphs
by Levent Yilmaz
Abstract: Exploratory modelling requires not only parametric but also structural and representational variability. The ability to systematically vary and experiment with multiple model features is paramount for problems that involve uncertainty and representational ambiguity. To facilitate such variation, a coherence-driven strategy is introduced for the management and evaluation of feature selections. The feature coherence specification and its associated metaprogramming system open new avenues for programmable abductive model building as well as model introspection, while automating the selection of model variants in the context of an evolving analysis. As learning takes place through simulation experiments, an increasingly accurate feature coherence model emerges to serve as an explanatory model that reveals which features cohere and are conducive to generating targeted systemic behaviours.
Keywords: exploratory modelling; cognitive modelling; variability management; feature-oriented modelling; agent-based modelling.
The design of a system dynamics model of crowdfunding for support of new knowledge-based IT startups
by Ali Haji Gholam Saryazdi, Ali Rajabzadeh Ghatari, Alinaghi Mashayekhi, Alireza Hassanzadeh
Abstract: Considering the problem of funding startups because of their nature, some entrepreneurs developed crowdfunding in which funding is done via social network. Crowdfunding is a complicated and dynamic phenomenon. In addition, studies conducted on crowdfunding are not significant in number and they have been conducted in exploratory and partial manner. As a result, it is necessary to adopt an approach capable of understanding complex dynamic phenomena so as to be able to explain crowdfunding. The present paper designs a system dynamics model of crowdfunding for support of new Iranian knowledge-based IT startups so as to highlight the complexities and dynamics of crowdfunding. The results of model simulation suggest that the reward model will develop to a higher extent due to higher alignment with IT business designs. Also, the model suggested that conforming with relevant regulations and monitoring of platforms improved the quality of IT business designs and secured the success of the companies after funding.
Keywords: crowdfunding; social network; crowd model building; System Dynamics 2.0; group model building; system dynamics approach.
Influence of alumina feeding dose distribution on superheat based on computational simulation
by Jiaming Zhu
Abstract: Bath superheat is one of the critical factors that limit how much added alumina is dissolved in a cell. Alumina dissolution has minimum requirement for superheat, however the superheat may not be uniform even when the pot with uniform alumina feeding dose (dose means the mass of alumina per shot feeding) distribution due to the heat dissipation at the end parts is obviously higher than the middle part, which leads to a lower temperature at the end parts. Therefore, it is difficult for alumina to be dissolved at the end parts where the superheat is too low, whereas it is easy to cause current efficiency loss due to higher superheat at the middle part. In this study, the influences of alumina feeding dose distribution on the alumina concentration and the bath temperature near the feeder were simulated in a computational numerical simulation, and then several cases with different feeding dose distribution were assessed by comparing the superheat per unit feeding dose. Furthermore, a methodology is proposed in this paper to optimise the alumina feeding dose distribution. It shows, in the result, that the cases with lower alumina feeding dose at the end parts have better superheat distribution than the cases with uniform alumina feeding dose distribution. Therefore the optimal one is the case with feeding dose distribution (1.6, 1.8, 2.0, 2.0, 1.8, 1.6 kg) of alumina in terms of the superheat per unit feeding dose.
Keywords: reduction cell; alumina feeding; superheat; alumina dissolution; bath temperature; simulation.
Model and simulation of extrusion force in biomass pelletization by ring die pellet mill
by Jie Liu, Risu Na, Haitang Cen
Abstract: The periodic change in extrusion force is the main cause of vibration in a ring die pellet mill. The generated vibration shortens the life of the ring die and also decreases its reliability and stability. According to the principle of biomass pelletisation, a new model of cyclic extrusion force calculation is established in this paper, by considering the changes in distance between ring die and roller against time. A dynamic simulation model of a ring die pellet mill with eccentricity was developed in LS-DYNA software, and the internal stress distribution of biomass was calculated. The obtained results revealed that the internal stress on biomass and the angle of extrusion both gradually decreased with the increasing distance between ring die and roller. The relationship between distance and extrusion force was linear when the distance was in the range of 0.51.5 mm. Extrusion force manifested a periodic variation, and its frequency was consistent with the rotational frequency of the ring die. The vibration amplitude of extrusion force was related to the eccentricity of the ring die.
Keywords: biomass pelletisation; ring die pellet mill; extrusion force; dynamic simulation.
A new semantic annotation approach for software vulnerability source code
by Chi Zhang, Jinfu Chen, Lei Zhang
Abstract: An efficient semantic annotation approach is proposed to annotate software vulnerability source code based on the Vulnerability Code Semantic Description Language (VCSDL) in this paper. A set of general annotation frameworks is proposed for two basic components: basic description information of vulnerability and vulnerability source code description information in the language. Specific annotation methods are studied for these two components, according to the annotation method of the basic description information of vulnerability. Also, the corresponding attribute in the VCSDL document structure is extracted to determine the labelling of the basic information of the vulnerability. While, according to the vulnerability source code information, the semantic annotation of the source code information of the vulnerability is implemented. The experimental results show that the proposed semantic annotation approach has a better effectiveness on the annotation of datasets with a simple code structure and a smaller scale. The success rate and accuracy of the proposed annotation are higher and the false positive rate and false negative rate are lower.
Keywords: software vulnerability; semantic annotation; vulnerability source code; vulnerability detection.
Path-based modelling of business processes
by Wilhelm Nüßer
Abstract: Modelling business processes as stochastic processes has a long tradition. Most models focus on the dynamics of the complete state of the process. In this article we propose an approach that concentrates on the stochastic paths of measurable quantities such as KPIs. Using this concept, a strong analogy to current results in statistical physics is exposed that leads to a general expression for the entropy of a business process as well as results quantifying the performance loss in processes due to fluctuations. Finally, path probabilities and averages of KPIs of a process are given in terms of business constraints expressed as variational principles.
Keywords: stochastic processes; business processes modelling; simulation; entropy; path probabilities; fluctuations.
Numerical simulation for fractional Phi-4 equation using homotopy Sumudu approach
by Abedel-Kareem Alomari, Gufran Darabseh, Mohammad Al-Jamal, Ramzi AlBadarneh
Abstract: In this study, we use the homotopy analysis method and the Sumudu transform to find the solution of fractional order partial differential equations. We focus primarily on the employment of the method for solving the fractional Phi-4 equation in one-dimensional spatial domain. The method can be extended easily for more general nonlinear equations. Convergence and error analysis are given. Numerical experiments show that the method is both effective and accurate, and suits such type of applications.
Keywords: Sumudu transform; homotopy analysis method; Phi-4 equation; convergence; unique solution.
A new transformation approach for complex systems modelling and simulation: application to an industrial control system
by Noureddine Seddari, Sofiane Boukelkoul, Abdelghani Bouras, Mohamed Belaoued, Mohammed Redjimi
Abstract: Owing to the increasing importance of complex systems, the problem of modelling and simulation of these systems, their approaches and solutions has been studied extensively these last years. In this paper, we present a novel approach to modelling and simulation of discrete event dynamic systems (DEDS), based on the combination of DEVS (Discrete Event Systems Specification) and AGR (Agent Group Role). In this study, the DEVS atomic models are transformed into agents and the DEVS coupled models into groups of agents. Thus, we provide a set of procedures and functions that allow the systematic transformation from DEVS into AGR models in order to be implemented in multiagent platforms. The proposed approach is validated by a case study, an application in the water supply used in natural gas liquefaction process.
Keywords: complex systems; discrete event dynamic systems; discrete event systems specification; modelling and simulation; agent/group/role model.
Service-oriented architecture-based design of bank-ATM and its verification with Petri net
by Amar Nath, Santanu Kumar Rath
Abstract: In the present era, IT-enabled business applications are very much observed to be pervasive and felt to be essential to manage an organisation. An organisation needs to update and upgrade its strategies to meet the challenges by adopting an IT-enabled solution to meet the agile customer requirements and market demand. An organisation has to embrace and underline technology that can be updated and modified without any severe bottlenecks. Service-Oriented Architecture (SOA) is one of the various architectural styles that provide agility to the organisation. SOA can help to meet different changes in requirements, viz., service composition, model-driven development, and service virtualisation. This paper illustrates the application of SOA in designing and implementing Automated Teller Machine (ATM) services, helpful in banking transactions. An ATM is a unit in the banking system, which is an embedded system that works on a distributed architecture. The incorporation of various services and their orchestration is implemented by using the Business Process Execution Language (BPEL) module under the OpenESB framework. However, in a complex and dynamic network environment, it is not easy to guarantee the quality of the BPEL process. So, it is very much essential to develop a proper BPEL process and validate it. In this study, the validation of the BPEL model is carried out by using the Petri net tool. The verification and validation activities are often considered essential to ensure the correctness of the system. The verification results obtained in this study are quite encouraging and prove validity.
Keywords: design of bank-ATM; improving bank-ATM performance; service-oriented architecture; orchestration of bank's services; verification with Petri net.
Miniaturised structure design, modelling and simulation process for active engine mounts
by Pu Wang, Rang-Lin Fan, Zeng-Yao Xing, Wei-Cun Zhang, Quan-Fa Wu
Abstract: Active engine mounts (AEMs) provide an effective solution to further improve the dynamic comfort of passenger cars in noise and vibration, and tend to be miniaturised to reduce the space occupation. This paper focuses on the miniaturised structure design process and the corresponding modelling and simulation. Two types of electromagnetic AEM with oscillating coil actuator or solenoid actuator were compared in space occupation, sealing performance, cost, static load capacity and dynamic performance, and their advantages and disadvantages were summarised, then the optimal design of the miniaturised structure was carried out using finite element modelling and lumped parameter modelling and simulations. The final design of the miniaturised AEM had small dimensions and similar performance to those ordinary AEMs. The miniaturised design and simulation process shown in this article can improve the use of space of AEM while ensuring no performance degradation.
Keywords: active engine mount; miniaturised structure design; oscillating coil actuator; solenoid actuator; finite element model; finite element analysis; performance simulation; powertrain mounting system; automotive.
Simulation-based improvement and modification for performances of hospitals: a case study
by Mohammad Mahdi Ershadi, Ahmad Shafaeizadeh
Abstract: It is necessary to improve the process of service provided to patients owing to increased patient referrals and the variety of patients visiting hospitals. Besides, patients satisfaction is affected by admission methods of the hospital, availability of its resources, admission waiting time, resource wastes, and patient feedback analysis. Therefore, hospital managers need to find current prioritised problems of the hospital and make efforts to solve various therapeutic processes about defined problems using appropriate planning. The prioritised problems are changed after every improvement scenario implementation. Besides, some results are unpredictable owing to the complexity of the hospital. Therefore, a simulation model for all departments of the hospital is proposed with a mathematical model and Taguchi method based on the real data obtained from a hospital. Decreasing resource wastes, the number of patients in the queue, and waiting time in different departments and increasing value-added time, use of resources, and productivity are considered in a mathematical model. All improvement scenarios are evaluated using the proposed model before implementation. Besides, FMEA is used to find the priority of problems and guide improvement teams. By analyzing these scenarios and examining their appropriate combination, a suitable plan designed for prioritised problems. The best improvement scenarios and their effects are defined using the proposed model in this paper. After the actual implementation of them, the difference between reality and the expected condition was less than 10%.
Keywords: discrete event simulation; multi-objective model; hospitals; healthcare system; failure modes and effects analysis.
Multilevel model of spatially allocated time use for takeout food ordering behaviour: a case study
by Jingyao Li, Shengchuan Zhao, Junyi Zhang
Abstract: The development of food delivery services in China has affected peoples space choice of dining. However, few studies have explored the influence of food delivery services in both space and time dimensions. To explore the activity decision-making mechanism which contains space and time dimensions, weekly panel data of spatially allocated time use was collected from undergraduate students. A multilevel spatially allocated time use model was built and based on the principle of utility maximisation. The research results prove that the spatially allocated time use in a whole day is a comprehensive decision-making process under the constraints of cross-sections of multiday survey, life circles and individual attributes. Takeout food ordering behaviour decreases travel demand for dining and other non-essential activities. It is concluded that takeout food ordering behaviour affects individual decision-making of spatially allocated time use in the whole day for both activity content and activity space.
Keywords: multilevel spatially allocated time use model; takeout food ordering behaviour; life circle; panel data of time use; undergraduate students.
Special Issue on: I3M 2018 Modelling and Simulation for Sustainable Development in Energy, Industry and Logistics
The cost analysis of a leading optics business in Saudi Arabia
by Ahmed Bakhsh
Abstract: Changing economic situations impose multiple challenges to industries, pushing decision-makers to optimise their processes better than their competitors. Discrete event simulation (DES) is one of the effective tools used by business leaders to enhance organisational performance. The present study used DES to minimise the processing cost of a leading optics business in Saudi Arabia. Data is collected from three branches located in Jeddah city to calculate the operating cost and delivery time of the products. A proposed solution is developed to replace three technical workshops inside every branch with one central workshop in the city. A number of replications are carried out to reach the optimal solution. Cost analysis is done to compare the process cost, delivery time and idle working hours of the two options. A significant reduction is observed in the process cost and delivery time of the products besides increasing the idle working hours of the technicians. These extra working hours can be used in receiving orders from the remaining branches of the organisation to enhance its productivity and profitability.
Keywords: DES; simulation; optics; decision-making.
Discrete-event simulation and data analysis for process flow improvements in a cabinet manufacturing facility
by Osama Mohsen, Sina Abdollahnejad, Narges Sajadfar, Yasser Mohamed, Simaan AbouRizk
Abstract: Project uniqueness and high degrees of customisation have always been challenging characteristics of construction projects and many related operations. This paper describes the simulation of a production line in a cabinet manufacturing facility carried out with the aim of better understanding and improving the production processes particularly associated with mass customisation. Discrete event simulation (DES) using Simphony.NET, a simulation modelling tool developed at the University of Alberta, is used to investigate and analyse an existing facility process. The purpose is to optimise productivity, reduce work-in-progress, and decrease idle time. The cabinet manufacturing factory in the presented study operates multiple production lines, produces different product types, and uses varying materials and finishings. In this specific case study, the simulation model is used to explore the challenges associated with increasing production to satisfy the rising demand for customised products. The result of the simulation study provides valuable information to achieve this goal.
Keywords: discrete-event simulation; cabinet manufacturing; mass customization; construction manufacturing; workflow improvement; modelling; simulation; data analysis.
Dynamic bond graph modelling of a two-phase cooling system with experimental analysis
by Mohamed Kebdani, Geneviève Dauphin-Tanguy
Abstract: The power electronics components are a significant source of heat power, which must be managed in spite of the limitations of conventional cooling systems. In order to surpass these restrictions, an innovative heat transfer system is here investigated: Two-phase Loop Mechanically Pumped (TLMP). An instrumented test rig is built with temperatures, pressures and mass flow rate sensors to analyse the flow response in both steady and transient states. In this work, we focus on the pump-pipes subsystem. The results confirm the systems ability to manage heat power dissipation by maintaining a stable power electronics temperature. In addition, the experiment results validate a thermo-hydraulic model based on bond graph theory. The variables used to simulate phase-change phenomena are: mass enthalpy, temperature and pressure. This modelling allows estimating the influence of external conditions on loop operation. Moreover, it offers sizing prospects for this kind of loop development on-board future missiles.
Keywords: cooling systems; thermal control; bond graphs; dynamic systems modelling; phase change; heat transfers; convection; conduction; turbomachines.
Special Issue on: I3M 2018 Virtual and Augmented Reality in Industry and Logistics
Augmented Reality based solar system for e-magazine with 3-D audio effect
by Martin Sagayam Kulandairaj, Alex J. Timothy, Chung Ching Ho Peter, Lawrence Henesey, Robert Bestak
Abstract: Augmented reality (AR) is the newest technology that can be applied to computer vision, audio, video and other sensor-based input projects into 3D vision. It is the backbone for all specialisation of science, medical and engineering concepts. Currently, the reading and learning method through AR-based approach is quite highly intensive rather than the existing methods such as papers, books and magazines. This strategy is more expensive but it is more interactive to the user in understanding the root concepts in an effective manner. This paper additionally explores the experiment on solar system revolution pattern along with 3D audio effect in spatial dimension. This novel idea inculcates more vibrancy in the current generation of students to understand the concepts with clear illustrations and demonstrations.
Keywords: augmented reality; solar system; 3D vision; computer vision; 3D audio effect; 3D modelling.
Enabling outdoor MR capabilities for head-mounted displays: a case study
by Christoph Praschl, Oliver Krauss, Gerald Zwettler
Abstract: This research work covers generic approaches to determine the outdoor position and orientation of an augmented reality device due to the lack of outdoor capability of depth-sensor or environmental recognition-sensor based devices currently available on the market. The determination of the orientation is primarily achieved with an attitude heading reference system (AHRS) for a rough estimation. Based on a connected/built-in video camera the accuracy at minor changes of the orientation is enhanced by applying registration to assess the differences in orientation between two video frames, compensating gyroscope drift errors. The position determination is achieved using GPS with a rover and base station real time kinematic beacon system to achieve enhanced precision. Results show that owing to sensor application AR hardware considered for indoor use can be retooled to properly work outdoors, at large distances and even inside running vehicles. Thus, future implementation of applications in various domains is facilitated.
Keywords: augmented reality; orientation; positioning; image registration; modelling AR training scenarios.
Interactive design and architecture by using virtual reality, augmented reality, and 3D printing
by Samira Hosseini, Nora Aguilera, Hector Quintero, Fernando Suarez-Warden
Abstract: How do new methods of teaching architectural design consider the elements of religion, spirituality, modernism, history and other cultural factors to address the physical, spatial and emotional needs of society? The research presented in this study revolves around this question. This article presents a proposal for educational training that emphasises these elements for students of design and architecture. This paper describes a basic design course taught to second-semester students in the Design and Architecture program at Tecnologico de Monterrey on the Monterrey campus in Mexico. In the project, the professors planned the course to direct the basic concepts of design toward the inner sensations and feelings of a human being. To support this objective, the professors employed the digital technologies of virtual reality (VR), augmented reality (AR), and 3D printing. Digital technology has penetrated visual communication and subsequently caused profound changes in architectural design education. The new educational models incorporate the use of technologies that emphasise the human senses. The classrooms are being transformed into interactive spaces where the teacher uses strategies requiring the participants to work together to achieve the objectives of the course. Acquiring software to create two-dimensional (2D) and three-dimensional (3D) representations has become easier. However, it is essential to know the elements and principles of architectural design to create final products that meet the needs of the users. The technologies can be a means to achieve these ends. The results of this project demonstrated an increase in spatial visualisation, analysis, and critical thinking among the students. Additionally, 100% of the students showed high satisfaction with the course and the experience of using these technological tools in the Design and Architecture course.
Keywords: educational innovation; spatial visualisation; virtual reality; augmented reality; 3D printing; design process; cultural elements in architectural design.
Effectiveness of acoustic AR-TA agent using localised footsteps corresponding to audience members' attitudes
by Yuki Kitagishi, Tomoko Yonezawa
Abstract: We investigated an auditory augmented reality (AR) teaching assistant agent (AATA) that walks according to the participating attitudes of the audience members in one-to-many communications, such as lectures with over 100 audience members. If participants are not focused on the lecture, it is difficult to make them pay attention. To improve such audience members' attitudes or to draw the audience members' attention to the appropriate target, we propose an AATA expressed by moving the localised footsteps using a direction-controllable parametric speaker (DCPS). We conducted experiments based on the hypothesis that footsteps approaching an audience member indirectly would cause the audience member to notice his or her problematic attitude. According to the results, the participants felt as though someone, the teaching assistant (TA) or the lecturer, was walking around them when they perceived the movement of the localised footsteps, and they felt the changes in the AATA's attention and intention towards them when the AATA's walking pattern changed. Accordingly, it is proposed that the AATA's movement can deliver an implicit message, such as a warning, to the audience members.
Keywords: one-to-many communication; acoustic AR-TA agent; lecturer support; audience attention; ambient interaction; parametric speaker; presence of agent; localised sound.
Special Issue on: ICSCIB 2018 Green Progression in Smart Cities and Intelligent Buildings
Deep activity recognition in smart buildings with commercial Wi-Fi devices
by Qizhen Zhou, Jianchun Xing, Yuhan Zhang, Qiliang Yang
Abstract: Activity recognition acts as a key enabler of smart building applications, such as behaviour analysis, health diagnosis and user authentication. However, existing methods require either burdensome equipment, or light and Line-Of-Sight (LOS) working conditions. To address this challenge, we propose DeepAR, a device-free human activity recognition system with prevailing Wi-Fi signals, which circumvents the use of dedicated devices. DeepAR mainly exploits two key techniques to recognise human daily activities. Firstly, a novel principle component extraction method is presented to capture the motion-induced distortions and discard the irrelevant interferences. Secondly, deep feature maps are constructed with time and frequency domain characteristics, and a deep Convolutional Neural Network (CNN) model is further applied to classify the activity labels. DeepAR is implemented with commercial Wi-Fi devices, and the performance is evaluated through extensive experiments. Experiment results show that DeepAR can achieve an average accuracy of 98.6% in a meeting room and 96.4% in a student office.
Keywords: channel state information; wireless sensing; deep learning; principle component analysis; smart building.
Fault diagnosis and location method for electrical power supply and distribution of buildings
by Jundong Fu, Tianhang Leng
Abstract: This paper presents a new fault diagnosis and location method for electrical power supply and distribution of buildings using Bayesian and Wavelet Neural Network (WNN). Aiming at the complex trunk-type power supply and distribution structure of buildings, wavelet transform (WT) is adopted to process the current, voltage and phase data of each branch to extract the features that can distinguish faults effectively. A fault diagnosis model based on Bayesian network is established by the above features. In order to improve the accuracy of WNN in fault location in buildings, a WNN method optimised by dragonfly algorithm (DA) is proposed to obtain better thresholds and weights, which are used to enhance the prediction ability. A simulation study was made with Matlab/Simulink to verify the performance of the proposed method on a power supply and distribution model.
Keywords: fault diagnosis and location method; electrical power supply and distribution of buildings; wavelet transform; Bayesian network; wavelet neural network; dragonfly algorithm.
Energy management of microgrid based on day-ahead and short-term optimisation
by Xiaohui Wang, Yiming Zheng
Abstract: Microgrid is an effective way to accept distributed renewable energy. However, owing to the uncontrollable and intermittent nature of renewable energy, coupled with the complex operational modes of microgrid, the scheduling of microgrid is more difficult to optimise and control. So it has become a key issue to optimise the coordinated operation of distributed generation units, energy storage devices and loads in energy management of microgrid. In order to guarantee the stable operation, an optimisation scheduling strategy with multiple time scales is proposed in this paper. Based on an independent microgrid, the output power of the equipment units in the microgrid are modelled and the objective functions and constraint conditions are determined. A day-ahead and short-term optimisation scheme is carried out, and the optimal scheduling program and combination of each distributed generators are optimised by the particle swarm optimisation (PSO) algorithm. The simulation results are analysed and summarised to verify the feasibility and validity of the proposed optimisation strategy.
Keywords: microgrid; energy management; multiple time scales; PSO; day-ahead optimisation; short-term optimisation.
Arancino.cc(TM): an open hardware platform for urban regeneration
by Maurizio Giacobbe, Francesco Alessi, Angelo Zaia, Antonio Puliafito
Abstract: The term 'metabolism' is generally used to define the set of chemical processes that occur within a living organism in order to maintain its life. Based on this definition, by analogy, we use the 'urban metabolism' concept to show the life of a city. Urban metabolism can be analysed and therefore its status evaluated (e.g., optimum, good, insufficient, etc.) based on measuring specific parameters (i.e., environmental temperature, humidity, pressure, quality of the air). Nowadays, although both technical and scientific literature present a multitude of methods, techniques and approaches concerning the monitoring and control of environmental parameters, the technological evolution requires a continuous updating of the same literature, as well as a regulatory adaptation. A city, in fact, is a set of very complex processes whose activities involve worldwide stakeholders (i.e., governments, entities, businesses and citizens), areas and infrastructures (e.g., buildings, homes, offices, urban parks, industrial plants) in order to offer sustainable services for people. The Internet of Things (IoT) paradigm helps the collection of a large amount of data that become available for decision makers and city managers, therefore impacting on all the three main aspects that characterise the concept of sustainability, together with the above mentioned urban metabolism: environmental, economic and social. Based on these considerations, in this paper we present and discuss the Arancino.cc(TM) system, mainly based on the use of open hardware and open software technologies in order to achieve 'green' benefits. These benefits essentially result in a better quality of life and a more efficient city management, and also optimise energy consumption and costs.
Keywords: urban metabolism; internet of things; smart city; sustainability; scientific data management.
A novel method for calculating the light energy distribution in building space
by Jundong Fu, Qing Chen
Abstract: In lighting design in buildings, the conventional algorithms may cause significant calculation error of light energy distribution and may not ensure illumination uniformity. In this paper, the radiation method in computer graphics is studied, combined with formula derivation, and two kinds of light energy calculation methods based on Lambert reflection model and non-Lambert reflection model are investigated. Two models, Model-1 and Model-2, are established for interior space of unequal height and non-rectangular interior space, respectively. Comparing simulation results of the models with existing models in a DIALux environment, the illumination uniformity calculation error of Model-1 is 30%, and the calculation error of Model-2 is within 5%. In addition, parameters of the models are modulated by experiments, in order to improve the accuracy of the models. Although Model-1 based on Lambert's reflection model runs fast, its accuracy needs to be improved. In the case of high simulation accuracy of spatial light environment, Model- 2 based on the non-Lambert reflection model is the best choice. At the same time, it is proved that the improved radiation method is feasible in calculating the light energy of an interior space with unequal height and non-rectangular shape.
Keywords: illumination calculation; light energy distribution; radiosity; Lambert reflection; non-Lambert reflection; global illumination.
Analysis of vehicle lane-changing behaviour at signalised intersection
by Yan Xing, Zhe Zhang, Weidong Liu, Qi Zhan, Chaojun Chu
Abstract: In order to analyse the characteristics of lane-changing behaviour at a signalised intersection, the desired speed of the vehicle and the lane-changing benefits were studied based on the theory of traffic flow. A vehicle lane-changing model is established in this research work, and the adjacent vehicle relative speed, the adjacent vehicle relative distance and the space for the vehicle lane-changing are considered. The feasibility of the model is discussed in the fifth part of the paper. Finally we analyse the influence of lane-changing behaviour through the actual data. The main content of the analysis is the impact of vehicle lane-changing behaviour on traffic capacity: the results show that traffic flow in the current lane and the traffic flow in the target lane are reduced owing to vehicle lane-changing at the intersection.
Keywords: lane-changing behaviour; vehicles’ speed; traffic flow; traffic efficiency.
Blockchain for smart city? Public service integration by strategic alliance
by Yi Zhang, Chenlei Xie
Abstract: The smart city, as a developing strategy for the global economy, has been initiated in many countries and presents a booming future. There are various researches suggesting that the blockchain is an indispensable tool for smart city construction, but how adapt it to a smart city strategy is not yet resolved. So the objectives of this article are focusing on applying blockchain to smart city strategies in the form of Strategic Alliance (SA) and providing suggestions for smart city development. The solution proposed in this research is to design a SA, the focus of which is to promote the organisational structure of the information transmission alliance in the blockchain, and to organise smart services by promoting the integration of smart solutions and the knowledge of blockchain. This research collected literature data, classified and analysed the collected literature data, and hence developed a smart city model with the application of blockchain technology based on our analysis.
Keywords: blockchain; smart city; knowledge integration; strategic alliance.