Computer Simulation Experiments Research Articles

Role of Street-Level Outdoor Thermal Comfort in Minimizing Urban Heat Island Effect by Using Simulation Program, Envi-Met: Case of Amman, Jordan

This study determines to what extend does computer modelling and simulation contribute to assessing methods in planning of rural and urban regulations related to lowering the effect of urban heat island. This was achieved by examining global warming and its relationship with urban heat islands and outdoor thermal comfort through relationship, definitions, problem, causes, parameters and mitigation techniques. The aim of the study is to assess urban design aspects, such as height and width ratio, positioning of buildings and provision of shade, and their role in the enhancement of urban microclimate which will have positive effects on both energy use in buildings and outdoor thermal comfort of pedestrians. This was followed by studying Jordan's practices in building regulations for related factors in order to choose parameters to apply in computer simulation program application, theories and experiments, giving out timeless and expense-less solutions and suggestions. Sample of chosen attributes and parameters were applied on a hypothetical typical of residential zone type (C) in the city of Amman, to finalize solutions in possible building regulations and recommendations.

Biomechanical loading test on reconstructed mandibles with fibular, iliac crest or scapula graft: a comparative study

Advantages and disadavantages of the three most commonly-used bone grafts for mandibular reconstruction are widely known, but biomechanical experimental studies are rare. We have done loading tests on cadaveric mandibles reconstructed with fibular, iliac crest, and scapular grafts using 3 different osteosynthesis systems to detect and compare their primary stability. Loading tests were done on mandibles with grafts from the fibula and iliac crest and published previously. A 4.5cm paramedian L-type defect was reconstructed with scapula using 2 monocortical non-locking plates, 2 monocortical locking plates, or a single bicortical locking plate/fracture gap in 18 human cadaveric mandibles. These were loaded on to the “Mandibulator” test bench and the movement of fragments in 3 dimensions was assessed and quantified by a PONTOS® optical measurement system. Comparison of the osteosynthesis groups showed that the miniplate was significantly superior to the 6-hole TriLock® plate for both fibular and iliac crest grafts. The fibular graft gave greater stability than the iliac crest and scapular grafts for all 3 osteosynthesis systems. All bony specimens offered sufficient resistance to mechanical stress within the recognised range of biting forces after mandibular reconstruction, independently of the choice of bone graft and osteosynthesis system used. Anatomical and surgical advantages need to be taken into account when choosing a graft. Stability can be maximised with a fibular graft, and further optimised by enlarging the binding area by using the “double barrel” method. Computer simulated experiments could segregate factors that biased results, such as morphological differences among cadavers.

NEW TECHNOLOGY OF TRAM GROOVED RAIL ROLLING

Despite of the great variety of rails types used in the industry, methods of their calibration are almost identical. However, calibration of girder rails, mainly used for tramways, in contrast to conventional rails has its own peculiarities in the formation of the girder. The paper presents the results of the computer simulation and industrial experiments that include investigations of the distribution of axial porosity and evaluation of the strain state of metal during its rolling in roughing and finishing calibers for the development and introduction of a new rolling technology of tramway girder rails. According to the results of the conducted computer simulation the industrial study of axial distribution of porosity by rolling in the rough box-caliber stand BD-1 and split rail caliber stand BD-2 was carried out. Microstructure examination was made at the templates of continuous casting block, after the second, after the seventh and ninth passes in the stands BD-1, BD-2. The results of the industrial experiment showed a good agreement with the computer simulation results

Fuzzy-based linguistic patterns as a tool for the flexible assessment of a priority vector obtained by pairwise comparisons

A novel approach to the assessment of a hierarchy vector generated by an expert pairwise comparison matrix is proposed. The ‘quality’ of a given hierarchy is measured using so-called ‘linguistic patterns’, i.e., specially constructed logical expressions, and an expert assessment matrix. The idea of this approach is based on a concept proposed previously as a flexible criterion for the domain of facility layout problems. The adaptation of the linguistic pattern approach to the assessment of a hierarchy vector also (by analogy to the analytic hierarchy process or AHP) facilitates evaluations of expert consistency. The proposed idea is shown to be less sensitive to potential expert errors than both the classical and fuzzy AHP techniques. The proposed approach is described in detail and illustrated with simple examples. Some features of the proposed approach were studied using computer simulation experiments and the results are reported together with the conclusions obtained.

An Image Compression Method Based on Wavelet Transform and Neural Network

Image compression is to compress the redundancy between the pixels as much as possible by using the correlation between the neighborhood pixels so as to reduce the transmission bandwidth and the storage space. This paper applies the integration of wavelet analysis and artificial neural network in the image compression, discusses its performance in the image compression theoretically, analyzes the multi-resolution analysis thought, constructs a wavelet neural network model which is used in the improved image compression and gives the corresponding algorithm. Only the weight in the output layer of the wavelet neural network needs training while the weight of the input layer can be determined according to the relationship between the interval of the sampling points and the interval of the compactly-supported intervals. Once determined, training is unnecessary, in this way, it accelerates the training speed of the wavelet neural network and solves the problem that it is difficult to determine the nodes of the hidden layer in the traditional neural network. The computer simulation experiment shows that the algorithm of this paper has more excellent compression effect than the traditional neural network method.

Development and implementation of the BlightPro decision support system for potato and tomato late blight management

A web-based decision support system (DSS) for potato and tomato late blight management has been developed which links several models into a system that enables prediction of disease dynamics based on weather conditions, crop information, and management tactics. Growers identify the location of their production unit of interest (latitude and longitude of field) and the system automatically obtains observed weather data from the nearest available weather station, and location-specific forecast weather data from the National Weather Service – National Digital Forecast Database. The DSS uses these weather data along with crop and management information to drive disease forecasting systems and a validated mechanistic model of the disease to generate location-specific management recommendations for fungicide application. An integrated alert system allows users to receive notification of upcoming critical thresholds via e-mail or text message. This system provides producers, consultants, researchers, and educators with a tool to obtain management recommendations, evaluate disease management scenarios, explore comparative epidemiology, or function as a teaching aid. In field and computer simulation experiments, DSS-guided schedules were influenced by prevailing weather and host resistance and resulted in schedules that improved the efficiency of fungicide use and also reduced variance in disease suppression when compared to a weekly spray schedule. In situations with unfavorable weather, the DSS recommended fewer fungicide applications with no loss of disease suppression. In situations of very favorable weather, the DSS recommended more fungicide applications but with improved disease suppression. The DSS provides an interactive system that helps users maximize the efficiency of their crop protection strategy by enabling well-informed decisions.

Impact of the H275Y and I223V Mutations in the Neuraminidase of the 2009 Pandemic Influenza Virus In Vitro and Evaluating Experimental Reproducibility.

The 2009 pandemic H1N1 (H1N1pdm09) influenza virus is naturally susceptible to neuraminidase (NA) inhibitors, but mutations in the NA protein can cause oseltamivir resistance. The H275Y and I223V amino acid substitutions in the NA of the H1N1pdm09 influenza strain have been separately observed in patients exhibiting oseltamivir-resistance. Here, we apply mathematical modelling techniques to compare the fitness of the wild-type H1N1pdm09 strain relative to each of these two mutants. We find that both the H275Y and I223V mutations in the H1N1pdm09 background significantly lengthen the duration of the eclipse phase (by 2.5 h and 3.6 h, respectively), consistent with these NA mutations delaying the release of viral progeny from newly infected cells. Cells infected by H1N1pdm09 virus carrying the I223V mutation display a disadvantageous, shorter infectious lifespan (17 h shorter) than those infected with the wild-type or MUT-H275Y strains. In terms of compensating traits, the H275Y mutation in the H1N1pdm09 background results in increased virus infectiousness, as we reported previously, whereas the I223V exhibits none, leaving it overall less fit than both its wild-type counterpart and the MUT-H275Y strain. Using computer simulated competition experiments, we determine that in the presence of oseltamivir at doses even below standard therapy, both the MUT-H275Y and MUT-I223V dominate their wild-type counterpart in all aspects, and the MUT-H275Y outcompetes the MUT-I223V. The H275Y mutation should therefore be more commonly observed than the I223V mutation in circulating H1N1pdm09 strains, assuming both mutations have a similar impact or no significant impact on between-host transmission. We also show that mathematical modelling offers a relatively inexpensive and reliable means to quantify inter-experimental variability and assess the reproducibility of results.

New rolling technology for streetcar girder rail

Despite the very diverse types of rails in industrial use, practically the same groove configurations may be used in rolling. However, the system used for streetcar girder rail is somewhat different. Computer simulation and industrial experiments permit the investigation of the axial-porosity distribution and assessment of the deformed state of the rolled metal in roughing and finishing. On that basis, a new rolling technology for streetcar girder rail has been developed. In the industrial research, the axial-porosity distribution in rolling with box grooves of the BD-1 roughing cell and slotted grooves in the BD-2 cell is investigated. The macrostructure is investigated on templates taken from the continuous-cast billet after the second, seventh, and ninth passes in the BD-1 and BD-2 cells. The results of computer simulation and the industrial trials are in good agreement.

Spline regression with variable penalty coefficients

The problem of constructing a semi-parametric spline regression model is considered. A new model of penalty splines with variable penalty coefficients is proposed. In the model, it is assumed that the coordinates of the basis points are determined by solving the optimization problem of minimizing the residual sum of squares. The choice of values of the penalty coefficients is based on the representation of the original model in the form of a random-effects model (variance component model). A series of computer simulation experiments was performed to reconstruct the regression line with different noise levels and in the presence of outliers. The results of computational experiments to reconstruct the regression line are presented that show greater accuracy of the new model in comparison with conventional models.

Productivity and resource use in intensified cropping systems in the Rolling Pampa, Argentina

Increasing cropland productivity is critical to meet future global demand of food, fibers and biofuels. Recent innovations in grain crop management are aimed at designing more ecologically complex cropping systems by growing doublecrop sequences comprising a great variety of crop species. The objectives of this study were to compare (i) the pattern of resource use and the productivity in cool-season crops and their influence on the following warm-season second crops, and (ii) the overall resource capture, resource use efficiency, and productivity of various single and double cropping systems. Hence, three field experiments under rainfed conditions and computer-simulated experiments were conducted in contrasting sites in the Rolling Pampa. Seven cropping systems were evaluated, which included five double crop sequences (rapeseed/soybean, wheat/soybean, barley/soybean, field pea/soybean, and field pea/maize) and maize and soybean as single crops. Cool-season crops differed in resource use, which therefore affected differently the following second crop. The highest and the lowest yields with double cropped soybean were produced after field pea and wheat, respectively. Soybean single crop was the least productive treatment because of low resource capture and moderate resource use efficiency. Double cropping systems including soybean as second crop outperformed soybean single crop productivity due to larger resource use. Comparatively, maize single crop used fewer resources but with higher efficiency than the cropping systems including soybean, which led to higher yields when water was not limiting. Field pea/maize double crop was the most productive system, since field pea allowed for long resource use periods, while maintaining similar resource use efficiency as maize single crops. Field experiment results were confirmed by crop yield simulations based on 39 years of environmental data from the same sites. Wheat/soybean double crops expanded and contributed to raise productivity in the Pampas with available farming technologies. However, novel crop type combinations appeared as feasible ways for improving resource use balance in the growing season among the component crops. This may raise the total annual productivity or, at least, increase the grain yield of soybean, the more profitable component at present. These findings have important implications regarding the ecological intensification of commodity grain cropping systems, which can be implemented by proactive farmers in the short-term in various regions of the world.

Direction identification of a moving ferromagnetic object by magnetic anomaly

We propose a novel method for identifying heading direction of a ferromagnetic target by processing magnetic measurements of two directions. The proposed method relies on the phase of the complex signal composed of two dimensions (2-D) magnetic anomaly signals accessed by two perpendicularly placed sensing units. Theoretical analysis based on a magnetic dipole model shows the derivative of phase of the composed complex signal can indicate the heading direction of a moving ferromagnetic object, no matter what the target magnetic moment magnitude and orientation are. Given flexibility and power savings of the measurement systems, a kind of small size, low power and low-frequency search coil magnetometer is developed as sensing units with the equivalent noise level of approximate 12 pT/Hz at about 1Hz. Computer simulation and real-word experiments have been conducted to test the performance of the method. The results show that the algorithm can identify the heading direction correctly at SNR of 9dB or more against 1/fα noises. Furthermore, the method can classify the direction with available saturated data. The simple implementation and low-computational complexity make the proposed method a potential candidate for real-time underwater area passive surveillance.

An Improved RAHP/DEA Method and the Application of the Physical Education Teaching Quality Assessment

The teaching quality assessment of physical education for the undergraduates has a very important role for the development of the college physical education teaching. In the age of information, we can improve effectively the speed and accuracy of the assessment through using rationally the computer technology. The AHP method and the DEA method are two kinds of evaluation methods which are used widely by the scholars. However, whether we use AHP or DEA, there are some defects on the using and scope. In order to overcome these shortcomings, we propose the RAHP/DEA method. This method combines the advantages of the RAHP method and the DEA methods. And we enlarge the range of use. Finally, in the computer simulation experiment, we adopt the method to evaluate the teaching quality of college physical education. The experimental results verify the rationality of the project evaluation and the decision making process. This shows that the evaluation system and the evaluation method meet the decision making ideas and the practical requirements.

Effect of element directivity on adaptive beamforming applied to high-frame-rate ultrasound.

High-frame-rate ultrasound is a promising technique for measurement and imaging of cardiovascular dynamics. In high-frame-rate ultrasonic imaging, unfocused ultrasonic beams are used in transmit and multiple focused receiving beams are created by parallel beamforming using the delay and sum (DAS) method. However, the spatial resolution and contrast are degraded compared with conventional beamforming using focused transmit beams. In the present study, the minimum variance beamformer was examined for improvement of the spatial resolution in high-frame-rate ultrasound. In conventional minimum variance beamforming, the spatial covariance matrix of ultrasonic echo signals received by individual transducer elements is obtained without considering the directivity of the transducer element. By omitting the element directivity, the error in estimation of the desired signal (i.e., the echo from the focal point) increases, and as a result, the improvement of the spatial resolution is degraded. In the present study, the element directivity was taken into account in estimation of the spatial covariance matrix used in minimum variance beamforming. The effect of the element directivity on adaptive beamforming was evaluated by computer simulation and basic experiments using a phantom. In parallel beamforming with the conventional DAS beamformer, the lateral spatial resolution, which was evaluated from the lateral full width at half maximum of the echo amplitude profile in the basic experiment, was 0.50 mm. Using conventional amplitude and phase estimation (APES) beamforming, the lateral spatial resolution was improved to 0.37 mm. The lateral spatial resolution was further improved to 0.30 mm using the modified APES beamforming by considering the element directivity. Image contrast and contrast-to-noise ratios, respectively, were -12.3 and 6.5 dB (DAS), -32.8 and -11.3 dB (APES), and -7.0 and 3.1 dB (modified APES).

Broadband Coherent Signal Direction Finding Algorithm Improvement

TCT for broadband coherent signal direction finding algorithm, the problem of large amount of calculation, an improved method of direction finding is studied, and the only focus signal subspace of the matrix is used to calculate, able to quickly estimate two-dimensional broadband coherent signal. Compared with the traditional TCT algorithm, in the case of without affecting the estimation precision greatly reduce amount of calculation and improve the signal DOA estimation of broadband real-time performance, and in an arbitrary planar array for the model computer simulation experiments have been carried out to verify the performance of it.

두 특성의 가치함수를 이용한 사출성형의 최적 설계

Optimizing multiple design characteristics which are usually in conflict with each other in the injection molding process is frequently becoming a critical problem for designers who work in this area. The purpose of this work is to develop an automated design methodology for optimizing two such design characteristics found in injection-molded parts. A value function based on decision-making theory is used as a means of evaluating the performance of a two-characteristic design alternative. Also, a design space reduction algorithm based on Taguchi's orthogonal arrays is utilized to discover an optimal design alternative. Verification of the developed design methodology is carried out for an actual model with two design characteristics, the weld line and the gate location, to be optimized in computer simulation experiments.

Tactical optimization of the oil palm agribusiness supply chain

A dynamic mathematical programming model of the oil palm harvest and extraction supply chain is presented. The model in question has nonlinear and mixed integer features both in its objective function and constraints. The nonlinear nature of the problem is treated in the solving procedure by adequately redefining some original variables, creating and penalizing some others, generating valid inequalities and modifying certain constraints. As a result, an equivalent MIP model is obtained and validated by a computational simulation experiment.

Combining computational models, semantic annotations and simulation experiments in a graph database.

Model repositories such as the BioModels Database, the CellML Model Repository or JWS Online are frequently accessed to retrieve computational models of biological systems. However, their storage concepts support only restricted types of queries and not all data inside the repositories can be retrieved. In this article we present a storage concept that meets this challenge. It grounds on a graph database, reflects the models’ structure, incorporates semantic annotations and simulation descriptions and ultimately connects different types of model-related data. The connections between heterogeneous model-related data and bio-ontologies enable efficient search via biological facts and grant access to new model features. The introduced concept notably improves the access of computational models and associated simulations in a model repository. This has positive effects on tasks such as model search, retrieval, ranking, matching and filtering. Furthermore, our work for the first time enables CellML- and Systems Biology Markup Language-encoded models to be effectively maintained in one database. We show how these models can be linked via annotations and queried.Database URL: https://sems.uni-rostock.de/projects/masymos/

UAV Gesture Interaction Design for Volumetric Surveillance

Numbers of UAV such as four or six rotor aircraft has been dramatically increased over recent years. And the volumetric surveillance based on UAV has been found to be extremely useful in haze visibility detection. however, owing to biunique flight control mode, the cost is higher and flexibility is limited, therefore, an effective human-UAV interaction is needed urgently, so that the UAV array could be controlled naturally by human hand. In this paper, a novel UAV gesture interaction scheme based on Kinect sensor and 2-D camera is presented. In the method, a kind of interaction interface is designed, then the UAV array is controlled in single or double hand. For gesture interaction details, based on the text search method proposed by Shahrouz, a new algorithm called “dummy independently component” is presented. In this approach, the finger movement is classified based on it's coherence, consequently, the number of parameters and database dimension are decreased, and search speed is improved. To verify the feasibility and effectiveness of scheme proposed above, final output is rendered with computer simulation and practical experiment.

Recovering 3D Shape with Absolute Size from Endoscope Images Using RBF Neural Network.

Medical diagnosis judges the status of polyp from the size and the 3D shape of the polyp from its medical endoscope image. However the medical doctor judges the status empirically from the endoscope image and more accurate 3D shape recovery from its 2D image has been demanded to support this judgment. As a method to recover 3D shape with high speed, VBW (Vogel-Breuß-Weickert) model is proposed to recover 3D shape under the condition of point light source illumination and perspective projection. However, VBW model recovers the relative shape but there is a problem that the shape cannot be recovered with the exact size. Here, shape modification is introduced to recover the exact shape with modification from that with VBW model. RBF-NN is introduced for the mapping between input and output. Input is given as the output of gradient parameters of VBW model for the generated sphere. Output is given as the true gradient parameters of true values of the generated sphere. Learning mapping with NN can modify the gradient and the depth can be recovered according to the modified gradient parameters. Performance of the proposed approach is confirmed via computer simulation and real experiment.

Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System.

The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system.