A surface blending approach for displacement features on freeform surfaces

Embedding a number of displacement features into a base surface is common in industrial product design and modeling, where displaced surface regions are blended with the unmodified surface region. The cubic Hermite interpolant is usually adopted for surface blending, in which tangent plane smoothness across the boundary curve is achieved. However, the polynomial degree of the tangent field curve obtained symbolically is considerably higher, and the reduction of the degree of a freeform curve is a non-trivial task. In this work, an approximation surface blending approach is proposed to achieve tangential continuity across the boundary curve. The boundary curve is first offset in the tangent field with the user-specified tolerance, after which it is refined to be compatible with the offset curve for surface blending. Since the boundary curve is offset in a three-dimensional (3D) space, the local self-intersection in the offset curve is addressed in a 2D space by approximately mapping the offset vectors in the respective tangent planes to the parameter space of the base surface. The proposed algorithm is validated using examples, and the normal vector deviation along the boundary curve is investigated.     

Building language resources for a Multi-Engine English-Filipino machine translation system

In this paper, we present the building of various language resources for a multi-engine bi-directional English-Filipino Machine Translation (MT) system. Since linguistics information on Philippine languages are available, but as of yet, the focus has been on theoretical linguistics and little is done on the computational aspects of these languages, attempts are reported here on the manual construction of these language resources such as the grammar, lexicon, morphological information, and the corpora which were literally built from almost non-existent digital forms. Due to the inherent difficulties of manual construction, we also discuss our experiments on various technologies for automatic extraction of these resources to handle the intricacies of the Filipino language, designed with the intention of using them for the MT system. To implement the different MT engines and to ensure the improvement of translation quality, other language tools (such as the morphological analyzer and generator, and the part of speech tagger) were developed.     

Registration using natural features for augmented reality systems

Registration is one of the most difficult problems in augmented reality (AR) systems. In this paper, a simple registration method using natural features based on the projective reconstruction technique is proposed. This method consists of two steps: embedding and rendering. Embedding involves specifying four points to build the world coordinate system on which a virtual object will be superimposed. In rendering, the Kanade-Lucas-Tomasi (KLT) feature tracker is used to track the natural feature correspondences in the live video. The natural features that have been tracked are used to estimate the corresponding projective matrix in the image sequence. Next, the projective reconstruction technique is used to transfer the four specified points to compute the registration matrix for augmentation. This paper also proposes a robust method for estimating the projective matrix, where the natural features that have been tracked are normalized (translation and scaling) and used as the input data. The estimated projective matrix will be used as an initial estimate for a nonlinear optimization method that minimizes the actual residual errors based on the Levenberg-Marquardt (LM) minimization method, thus making the results more robust and stable. The proposed registration method has three major advantages: 1) It is simple, as no predefined fiducials or markers are used for registration for either indoor and outdoor AR applications. 2) It is robust, because it remains effective as long as at least six natural features are tracked during the entire augmentation, and the existence of the corresponding projective matrices in the live video is guaranteed. Meanwhile, the robust method to estimate the projective matrix can obtain stable results even when there are some outliers during the tracking process. 3) Virtual objects can still be superimposed on the specified areas, even if some parts of the areas are occluded during the entire process. Some indoor and outdoor experiments have been conducted to validate the performance of this proposed method.     

Plastic Injection Molding of High-Aspect Ratio Micro-Rods

Technological advancements have led to an increase in demand for fabrication of small and cheap miniature components or parts, especially in the medical and electronic fields. In this research work, micro-rods of varying lengths and diameters were molded using a specially designed tabletop injection molding machine. The main purpose was to investigate whether complete filling of the microcavities was possible and whether small cavity openings will restrict melt flow into the cavities.

Process parameters, such as injection pressure, mold temperature and melt temperature were varied. The micro-rods obtained were analyzed with Scanning Electron Micrographs (SEM). The results showed that injection pressure was the most important parameter for microinjection molding. The use of a vacuum system also yielded better results.     

Quantification of multiple bioagents with wireless, remote-query magnetoelastic microsensors

This paper presents a micromagnetoelastic sensor array for simultaneously monitoring multiple biological agents. Magnetoelastic sensors, made of low-cost amorphous ferromagnetic ribbons, are analogous and complementary to piezoelectric acoustic wave sensors, which track parameters of interest via changes in resonance behavior. Magnetoelastic sensors are excited with magnetic ac fields, and, in turn, they generate magnetic fluxes that can be detected with a sensing coil from a distance. As a result, these sensors are highly attractive, not only due to their small size and low cost, but also because of their passive and wireless nature. Magnetoelastic sensors have been applied for monitoring pressure, temperature, liquid density, and viscosity, fluid How velocity and direction, and with chemical/biological responsive coatings that change mass or elasticity, various biological and chemical agents. In this paper, we report the fabrication and application of a six-sensor array for simultaneous measurement of Escherichia coli O157:H7, staphylococcal enterotoxin B, and ricin. In addition, the sensor array also monitors temperature and pH so the measurements are independent from these two parameters.     

Feature-based design in a distributed and collaborative environment

In this paper, a client/server framework has been developed to enable a dispersed team to accomplish a feature-based design task collaboratively. A manipulation client+modelling server infrastructure has been proposed to facilitate consistent primary information modelling for multiple users and adaptability of the system. Based on feature-to-feature relationships, a distributed feature manipulation mechanism has been proposed to filter the varied information of a working part during a co-design activity to avoid unnecessary re-transferring of the complete large-size CAD files each time when any interactive operation is imposed on the model by a client. In the distributed environment, a design task and the engaged clients are organised and connected through working sessions generated and maintained dynamically with a collaborative server. The environment is open to downstream manufacturing analysis modules to achieve distributed concurrent engineering.     

Activity-based cost-modelling procedures for PCB assembly

Accurate product cost estimation is important in decisions which involved the selection of the least-cost design among alternative designs and the economic feasibility of a product. An accurate cost-estimating procedure would include the cost of materials and all activities that incur cost.This paper presents the development of cost models for printed circuit board (PCB) assembly which will take into consideration activities that incur cost owing to complexity, volume and batch size of PCB manufactured. All activities are allocated into three level bases and they are unit-level cost, batch-level cost and product-level cost. The cost of assembling one PCB is the summation of all these three costs. A case example is presented to illustrate the application of the models developed.     

Reduced migration from flexible poly(vinyl chloride) of a plasticizer containing beta-cyclodextrin derivative

The migration of endocrine-disrupting di-(2-ethylhexyl) phthalate (DEHP) poses a serious threat to public health and the environment. In this study, we successfully prepared a plasticizerwith reduced DEHP migration by directly incorporating 2,3,6-per-O-benzoyl-beta-cyclodextrin (Bz-beta-CD) into DEHP. Bz-beta-CD was prepared by esterification between the hydroxyl groups of beta-CD and benzoyl chloride. The presence of this cyclodextrin is expected to facilitate formation of stable complexes through pi-pi association with DEHP molecules. The flexible PVC was prepared with a gelation-fusion process that uses the prepared migration-resistant plasticizer, and its properties (flexibility, thermal stability, and clarity) were evaluated by carrying out DSC and tensile testing, TGA, and haze testing, respectively. No significant changes in the physical properties of the flexible PVC were observed when Bz-beta-CD was added. DEHP migration tests were carried out for the flexible PVC according to the ISO 3826:1993(E) test method, and the quantity of migrated DEHP was then determined with UV-vis spectroscopy. It was found that the addition of Bz-beta-CD decreases the levels of DEHP migration from the flexible PVC samples by almost 40%. We investigated the molecular interaction between Bz-beta-CD and DEHP using molecular mechanics simulations, and we conclude that this reduction in DEHP migration is due to the formation of stabilized pi-pi attractive association and inclusion complexes of Bz-beta-CD and DEHP in flexible PVC.