MASAS—A user-friendly simulation tool for modeling the fate of anthropogenic substances in lakes

MASAS is a computer simulation tool to investigate anthropogenic organic compounds in lakes. Models included are based on a dynamic one-dimensional vertical lake model describing the time-dependent concentration of a compound in the water column and in the sediment. Provision of data is ensured by library files. Interactive specification of transport and transformation processes yields models of different complexity, suitable for the initial assessment of chemicals and for chemodynamic studies. A hypothetical spill of an insecticide (disulfoton) serves as an illustration. Aspects relevant to the development of user-friendly software in the environmental sciences are discussed. User-friendliness is found to depend more on program concepts than on a particular user interface. The management of data sets on lakes and compounds, and the implementation of transport and transformation processes in MASAS exemplify the significance of modularization, program data structures, the use of metaphors, and the distinction between automatic and user-controlled program functions.     

DCworms – A tool for simulation of energy efficiency in distributed computing infrastructures

In the recent years, energy-efficiency of computing infrastructures has gained a great attention. For this reason, proper estimation and evaluation of energy that is required to execute data center workloads became an important research problem. In this paper we present a Data Center Workload and Resource Management Simulator (DCworms) which enables modeling and simulation of computing infrastructures to estimate their performance, energy consumption, and energy-efficiency metrics for diverse workloads and management policies. We discuss methods of power usage modeling available in the simulator. To this end, we compare results of simulations to measurements of real servers. To demonstrate DCworms capabilities we evaluate impact of several resource management policies on overall energy-efficiency of specific workloads executed on heterogeneous resources.     

Optimal control of an electric vehicle’s charging schedule under electricity markets

As increasing numbers of electric vehicles (EVs) enter into the society, the charging behavior of EVs has got lots of attention due to its economical difference within the electricity market. The charging cost for EVs generally differ from each other in choosing the charging time interval (hourly), since the hourly electricity prices are different in the market. In this paper, the problem is formulated into an optimal control one and solved by dynamic programming. Optimization aims to find the economically optimal charging solution for each vehicle. In this paper, a nonlinear battery model is characterized and presented, and a given future electricity prices is assumed and utilized. Simulation results indicate that daily charing cost is reduced by smart charing.     

Hardware-in-the-loop simulation for the design and verification of the control system of a series–parallel hybrid electric city-bus

Hybrid electric buses have been a promising technology to dramatically lower fuel consumption and carbon dioxide (CO₂) emission, while energy management strategy (EMS) is a critical technology to the improvements in fuel economy for hybrid electric vehicles (HEVs). In this paper, a suboptimal EMS is developed for the real-time control of a series–parallel hybrid electric bus. It is then investigated and verified in a hardware-in-the-loop (HIL) simulation system constructed on PT-LABCAR, a commercial real-time simulator. First, an optimal EMS is obtained via iterative dynamic programming (IDP) by defining a cost function over a specific drive cycle to minimize fuel consumption, as well as to achieve zero battery state-of-charge (SOC) change and to avoid frequent clutch operation. The IDP method can lower the computational burden and improve the accuracy. Second, the suboptimal EMS for real-time control is developed by constructing an Elman neural network (NN) based on the aforementioned optimal EMS, so the real-time suboptimal EMS can be used in the vehicle control unit (VCU) of the hybrid bus. The real VCU is investigated and verified utilizing a HIL simulator in a virtual forward-facing HEV environment consisting of vehicle, driver and driving environment. The simulation results demonstrate that the proposed real-time suboptimal EMS by the neural network can coordinate the overall hybrid powertrain of the hybrid bus to optimize fuel economy over different drive cycles, and the given drive cycles can be tracked while sustaining the battery SOC level.     

A new method of classification for Landsat data using the ‘watershed’ algorithm

Many methods of classifying satellite imagery have been suggested. Most of the accepted methods, either supervised or unsupervised, are founded on the assumption that the radiance values of a particular ground cover type can be characterized by some probability distribution having a central value(s) and a range parameter(s). This assumption is rarely, if ever, tenable and hence the methods must produce unnecessarily high rates of misclassification. Thus there is a need for an approach which avoids this type of assumption. Pattern recognition techniques, e.g. the ‘watershed’ algorithm, can be used to divide up the radiance-frequency domain, provided the radiance values can be reduced to 2 dimensions. These methods do not presuppose any ‘shape’ for the radiance-frequency distributions and therefore provide an unbiased aid to the interpretation of satellite imagery.     

A web-based platform for the simulation–optimization of industrial problems

This study presents a platform for industrial, real-world simulation–optimization based on web techniques. The design of the platform is intended to be generic and thereby make it possible to apply the platform in various problem domains. In the implementation of the platform, modern web techniques, such as Ajax, JavaScript, GWT, and ProtoBuf, are used. The platform is tested and evaluated on a real industrial problem of production optimization at Volvo Aero Corporation, a company that develops and manufactures high-technology components for aircraft and gas turbine engines. The results of the evaluation show that while the platform has several benefits, implementing a web-based system is not completely straightforward. At the end of the paper, possible pitfalls are discussed and some recommendations for future implementations are outlined.     

MNPBEM – A Matlab toolbox for the simulation of plasmonic nanoparticles

MNPBEM is a Matlab toolbox for the simulation of metallic nanoparticles (MNP), using a boundary element method (BEM) approach. The main purpose of the toolbox is to solve Maxwell?s equations for a dielectric environment where bodies with homogeneous and isotropic dielectric functions are separated by abrupt interfaces. Although the approach is in principle suited for arbitrary body sizes and photon energies, it is tested (and probably works best) for metallic nanoparticles with sizes ranging from a few to a few hundreds of nanometers, and for frequencies in the optical and near-infrared regime. The toolbox has been implemented with Matlab classes. These classes can be easily combined, which has the advantage that one can adapt the simulation programs flexibly for various applications.Program summaryProgram title: MNPBEMCatalogue identifier: AEKJ_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEKJ_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: GNU General Public License v2No. of lines in distributed program, including test data, etc.: 15 700No. of bytes in distributed program, including test data, etc.: 891 417Distribution format: tar.gzProgramming language: Matlab 7.11.0 (R2010b)Computer: Any which supports Matlab 7.11.0 (R2010b)Operating system: Any which supports Matlab 7.11.0 (R2010b)RAM: ?1 GByteClassification: 18Nature of problem: Solve Maxwell?s equations for dielectric particles with homogeneous dielectric functions separated by abrupt interfaces.Solution method: Boundary element method using electromagnetic potentials.Running time: Depending on surface discretization between seconds and hours.     

A Haar wavelet quasilinearization approach for numerical simulation of Burgers’ equation

In this paper, an efficient numerical scheme based on uniform Haar wavelets and the quasilinearization process is proposed for the numerical simulation of time dependent nonlinear Burgers’ equation. The equation has great importance in many physical problems such as fluid dynamics, turbulence, sound waves in a viscous medium etc. The Haar wavelet basis permits to enlarge the class of functions used so far in the collocation framework. More accurate solutions are obtained by wavelet decomposition in the form of a multi-resolution analysis of the function which represents a solution of boundary value problems. The accuracy of the proposed method is demonstrated by three test problems. The numerical results are compared with existing numerical solutions found in the literature. The use of the uniform Haar wavelet is found to be accurate, simple, fast, flexible, convenient and has small computation costs.     

‘KRISP’: A represnetation for the semantic interpretation of texts

KRISP is a representation system and set of interpretation protocols that is used in the Sparser natural language understanding system to embody the meaning of texts and their pragmatic contexts. It is based on a denotational notion of semantic interpretation, where the phrases of a text are directly projected onto a largely pre-existing set of individuals and categories in a model, rather than first going through a level of symbolic representation such as a logical form. It defines a small set of semantic object types, grounded in the lambda calculus, and it supports the principle of uniqueness and supplies first class objects to represent partially-saturated relationships.KRISP is being used to develop a core set of concepts for such things as names, amounts, time, and modality, which are part of a few larger models for domains including Who's News and joint ventures. It is targeted at the task of information extraction, emphasizing the need to relate entities mentioned in new texts to a large set of pre-defined entities and those read about in earlier articles or in the same article.     

Farmers’ perceptions of exoskeleton use on farms: Finding the right tool for the work(er)

Despite the promising impact that exoskeletons might have on reducing MSDs, on-farm investigations of exoskeletons are limited. This study explored farmers' perceptions of the feasibility and practicality of exoskeleton use in Canadian prairie grain and livestock farm operations. Fifteen farm workers (age 25–70 years) used a passive back-supporting exoskeleton during standardized and unique tasks at their own farms. They then participated in semi-structured interviews regarding their experiences during the trials, advantages and disadvantages of exoskeleton use, suggested improvements, and speculation about feasibility of exoskeleton use on farms. Interview analysis revealed seven overlapping and inter-related themes: ‘safety’, ‘comfort’, ‘jobs & timing’, ‘health’, ‘mobility’, ‘ease of use’, and ‘productivity’. Interviews showed diversity in farmers' perceptions of exoskeleton performance within these themes, demonstrating that successful implementation on farms will require alignment between the exoskeleton design, the users, and the tasks being performed. Findings can facilitate development of future designs as well as appropriate implementation strategies for the farm environment, with the ultimate goal of improving the health, quality of life, and productivity of farmers and workers facing similar ergonomic hazards.     

A simulation of the Heckscher–Ohlin theorem

The Heckscher–Ohlin (H–O) theorem is one of the classical results in international trade theory. In the real world, however, this tendency has not been observed. Two restrictive assumptions are required for this theorem to hold. One is the identity of utility functions between the two trading countries, and the other relates to production functions. In this paper, simulations are conducted to identity which assumption is more important in order for the H–O theorem to hold. Production functions (constant returns to scale) and utility functions are assumed to be of Cobb–Douglas type. In the first simulation, 10,000 pairs of parameters on production and utility functions are selected randomly, where production function on both countries are identical and utility functions can be different. The H–O property is observed for approximately 70% of the solutions. In the second simulation, the same simulation is conducted where utility functions in both countries are identical and production functions can be different. Then, H–O property is observed for approximately 50% of the solutions.     

A novel time-marching scheme using numerical Green’s functions: A comparative study for the scalar wave equation

The present paper presents the formulation of a novel time-marching method based on the Explicit Green’s Approach (ExGA) to solve scalar wave propagation problems. By means of the weighted residual method in both time and space, the time integral expression concerning the ExGA is readily established. The arising ExGA time integral expression is spatially discretized in a finite element sense and a recursive scheme that employs time-domain numerical Green’s function matrices is adopted to evaluate the displacement and the velocity vectors. These Green’s matrices are computed by the time discontinuous Galerkin finite element method only at the first time step. The system of coupled equations originated from the time discontinuous Galerkin method is then solved by an iterative predictor–multicorrector algorithm. Once the Green’s matrices are computed, no iterative process is required to obtain the displacement and the velocity vectors at any time level. At the end of the paper, numerical examples are presented in order to compare the proposed approach with other approaches.     

Evaluation of the usefulness of ‘Marvin’; a computerized assessment tool for investigative interviewers of children

This study examined the usefulness of a computerized developmental assessment tool, designed to provide investigative interviewers with knowledge about children's understanding of spatial, temporal, numerical, and color terms that may be relevant to the forensic setting. Specifically, the effect of the computer program (compared to a standard verbal and no assessment) was examined on 4- to 5-year-old children's recall of an independent event and their enjoyment of the interview process. In addition, children's performance on the computerized and verbal developmental assessment was compared with their performance when recalling the independent event. Overall, the children rated the assessment conducted on computer more favorably than the verbal assessment. Further, the verbal assessment elicited responses that were more consistent with their responses about the event than the computerized assessment. However, there was no difference in the accuracy and detail of children's responses about the independent event, irrespective of whether the children received the computerized or verbal assessment, or no assessment. Directions for future research are discussed.     

A framework for preservation of cloud users’ data privacy using dynamic reconstruction of metadata

In the rising paradigm of cloud computing, attainment of sustainable levels of cloud users’ trust in using cloud services is directly dependent on effective mitigation of its associated impending risks and resultant security threats. Among the various indispensible security services required to ensure effective cloud functionality leading to enhancement of users’ confidence in using cloud offerings, those related to the preservation of cloud users’ data privacy are significantly important and must be matured enough to withstand the imminent security threats, as emphasized in this research paper. This paper highlights the possibility of exploiting the metadata stored in cloud's database in order to compromise the privacy of users’ data items stored using a cloud provider's simple storage service. It, then, proposes a framework based on database schema redesign and dynamic reconstruction of metadata for the preservation of cloud users’ data privacy. Using the sensitivity parameterization parent class membership of cloud database attributes, the database schema is modified using cryptographic as well as relational privacy preservation operations. At the same time, unaltered access to database files is ensured for the cloud provider using dynamic reconstruction of metadata for the restoration of original database schema, when required. The suitability of the proposed technique with respect to private cloud environments is ensured by keeping the formulation of its constituent steps well aligned with the recommendations proposed by various Standards Development Organizations working in this domain.     

Multi-agent simulation for the dominant players’ behavior in supply chains

This paper describes a multi-agent simulation model for analyzing the dominant player’s behavior of supply chains. The supply chain consists of a raw material supplier and component supplier, a manufacturer and retailer are simulated by the model. The main sources of uncertainty for the dominant players’ behavior are identified, including of market information, selling prices, purchasing prices. The economic phenomenon (Players can maintain their profits stably in spite of decreasing the selling price) is shown by the model, and the SPP (Stable Profit Platform) is used to indicate the level of domination power for the player achievement. Moreover, the model can also be extended to various supply chain for better understanding of the dominant players’ behavior and improving the effective decision making of supply chain cooperation.     

Ready simulation for concurrency: It’s logical!

This article provides new insight into the connection between the trace-based lower part of van Glabbeek’s linear-time, branching-time spectrum and its simulation-based upper part. We establish that ready simulation is fully abstract with respect to failure inclusion, when adding the conjunction operator that was proposed by the authors in [TCS 373 (1–2) 19–40] to the standard setting of labelled transition systems with (CSP-style) parallel composition. More precisely, we actually prove a stronger result by considering a coarser relation than failure inclusion, namely a preorder that relates processes with respect to inconsistencies that may arise under conjunctive composition.Ready simulation is also shown to satisfy standard logic properties. In addition, our semantic formalism proves itself robust when adding disjunction, external choice and hiding operators, and is thus suited for studying mixed operational and logic languages. Finally, the utility of our formalism is demonstrated by means of a small example that deals with specifying and reasoning about mode logics within aircraft control systems.     

Optimal energy consuming planning for a home‑based microgrid with mobility constraint of electric vehicles and tractors

This research deals with the energy management problem to minimize the cost of non-renewable energy for a small-scale microgrid with electric vehicles (EV) and electric tractors (ET). The EVs and ETs function as batteries in the power system, while they often have to leave it for their mobility and agricultural work. Each State of Charge (SoC), which is the charge rate of the battery from 0 to 1, and the operating time of ETs are optimized under the assumption that the required electrical energy, the arrival and departure time of EVs, and the working time of ETs are given by users, but they include uncertainties. In this paper, we deal with these uncertainties by constraints for robust energy planning and expected optimization based on scenarios, and show that the scheduling of the SoC assuming the worst case and the optimal home-based power consumption planning that considers the cost of each scenario corresponding to each variation can be obtained. Our proposed method is formulated as a mixed integer linear programming (MILP), and numerical simulations show that the optimal cooperative operation among multiple houses can be obtained and its global optimal or sub-optimal solution can be quickly obtained by using CPLEX.     

A new plug-in for the creation of OPC servers based on EcosimPro© simulation software

OPC (Ole for Process Control) is an Interoperability Standard that is being extensively used at industry because it facilitates integration and communication between heterogeneous subsystems. From the point of view of the simulation software, OPC support is a bonus that enhances the communication capability between simulation models. In this paper, we describe the development issues for incorporating OPC support into the EcosimPro© modelling and simulation software. The result of this project is a commercially available plug-in that transforms an EcosimPro© model into an OPC server ready to exchange data with other subsystems. Possibilities of the new functionality of the tool are also discussed.