Current Issue : April - June Volume : 2011 Issue Number : 2 Articles : 6 Articles
Three dimensional surfaces are frequently described by a net of curves lying in orthogonal cutting planes with detail lines. These curves are obtained by digitizing a physical model or a drawing and then fitting a mathematical curve to the digitized data. The technique for obtaining a mathematical curve to the digitized is Cubic spline. This method is referred as curve fairing technique. They are characterized by the fact that the derived mathematical curve passes through each and every data points. Conclusions regarding the cubic splines are made.The cubic spline is a spline constructed of piecewise third-order polynomials which pass through a set of n control points. The second derivative of each polynomial is commonly set to zero at the endpoints, since this provides a boundary condition that completes the system of n-2 equations. This produces a so-called "natural" cubic spline and leads to a simple tridiagonal system which can be solved easily to give the coefficients of the polynomials. However, this choice is not the only one possible and other boundary conditions can be used instead. Cubic splines are implemented in modeling as b-Spline Curve. The cubic spline advantageous since it is the lowest degree curve which allows a point of inflection and which has the ability to twist trough space....
Fuel consumption is the single largest variable cost during field operation of tractors and also one of the most influential parameters controlling the salability of the vehicle, particularly in developing countries. Hence there is a great need for development of a system which can minimize the fuel consumption at any given load for a tractor. The system is required to design by keeping in mind the low education level of farmers of developing countries like India and natural aversion of these farming communities towards complex system during cumbersome field operation. Therefore the prime objective of this paper was to design and develop a simple digital fuel economizer (DFE) system for developing countries like India. Gear-up-throttle-down (GUTD) technique to match the load on tractor during field operation is a popular means to have better fuel economy. The new DFE system was designed to work like a GUTD guidance system. A microcontroller, inductive type proximity sensor and an analog to digital converter have been used to develop the DFE system....
Virtual Prototypes are increasingly being used during design reviews of specialized buildings such as healthcare facilities. However, most of these virtual prototyping approaches do not allow the reviewers and end users to interact directly, in real time with elements and objects within the virtual model. This paper focuses on a method to combine the use of 3D game engines with the emerging experience based design approach for healthcare facilities to develop a systematic approach to scenario-based design review of healthcare facilities in an interactive virtual environment. First, a virtual facility prototyping framework for rapid creation of a scenario based design review system is defined. Next, strategies to implement this framework to develop an Experience based Virtual Prototyping Simulator (EVPS) application are described. Design information workflows were developed and tested between various BIM authoring tools and the Unity game engine that is used for developing the interactive virtual prototype system. Finally, some lessons learned and issues are highlighted that help direct future research and implementation....
Railway is the key transport means in China including the Mainland, Taiwan, and Hong Kong. Consequent to so many big arson and accidental fires in the public transport systems including trains and buses, fire safety in passenger trains is a concern. Numerical simulations with Computational Fluid Dynamics on identified fire scenarios with typical train compartments in China will be reported in this paper. The heat release rate of the first ignited item was taken as the input parameter. The mass lost rate of fuel vapor of other combustibles was estimated to predict the resultant heat release rates by the combustion models in the software. Results on air flow, velocity vectors, temperature distribution, smoke layer height, and smoke spread patterns inside the train compartment were analyzed. The results are useful for working out appropriate fire safety measures for train vehicles and determining the design fire for subway stations and railway tunnels....
Pavement crack types provide important information for making pavement maintenance strategies. This paper proposes an automatic pavement crack classification approach, exploiting the spatial distribution features (i.e., direction feature and density feature) of the cracks under a neural network model. In this approach, a direction coding (D-Coding) algorithm is presented to encode the crack subsections and extract the direction features, and a Delaunay Triangulation technique is employed to analyze the crack region structure and extract the density features. As regarding skeletonized crack sections rather than crack pixels, the spatial distribution features hold considerable feature significance for each type of cracks. Empirical study indicates a classification precision of over 98% of the proposed approach....
Product design has normally been performed by teams, each with expertise in a specific discipline such as material, structural, and electrical systems. Traditionally, each team would use its member's experience and knowledge to develop the design sequentially. Collaborative design decisions explore the use of optimization methods to solve the design problem incorporating a number of disciplines simultaneously. It is known that such optimized product design is superior to the design found by optimizing each discipline sequentially due to the fact that it enables the exploitation of the interactions between the disciplines. In this paper, a bi-level decentralized framework based on Memetic Algorithm (MA) is proposed for collaborative design decision making using forearm crutch as the case. Two major decisions are considered: the weight and the strength. We introduce two design agents for each of the decisions. At the system level, one additional agent termed facilitator agent is created. Its main function is to locate the optimal solution for the system objective function which is derived from the Pareto concept. Thus to Pareto optimum for both weight and strength is obtained. It is demonstrated that the proposed model can converge to Pareto solutions....
Loading....