Applied Mechanics and Materials Vols. 58-60

Abstract: In design of artificial bones, in order to make it live together with the human bone, it should has the same porous structure as the human bone. But the Brep or solid model can’t achieve this. By transforming the three direction DEXEL model of polyhedrons into its VOXEL model and setting transparency attributes of VOXELs, the porous structure of artificial bone could be designed. By merging the same attribute VOXELs along y axis, a big VOXEL is formed. By this big VOXEL, the once sintering procedure of RP laser head is simulated. Layer by layer, the whole product is produced. Under Java2.0 and Java 3D, these algorithms were tested and some design examples were given.

Abstract: In this study, a wavelet neural network (WNN) model for predicting critical heat flux (CHF) is set up. The WNN mode combining the properties of the wavelet transform and the advantages of Artificial Neural Networks (ANN) has some advantages of its globe optimal searching, quick convergence speed and solving non-linear problem. The database used in the analysis is from the 1960’s, including 126 data points which cover these parameter ranges: pressure P=100–1,000 kPa, mass flow rate G=40–500 kgm^-2s^-1, inlet subcooling ΔT_sub=0–35^◦C and heat flux Q=20–8,000 kWm^-2. The WNN prediction results have a good agreement with experimental data. Simulation and analysis results show that the network model can effectively predict CHF.

Abstract: In view of the demand of circuit fault simulation analysis, a novel circuit simulator for fault simulation was designed to overcome the shortcomings of traditional circuit simulation tools in fault simulation. The principles and method of this simulator were proposed, which focus on the realization of the basic functions and weakens detail characteristics. Based on the method, the components simulation models and fault models with the combination of the numerical variable with logical variable were built. Moreover, the implementation algorithm and simulation flow were introduced to show how to simulate a circuit based on this simulation model. At last, an example was simulated to verify the feasibility of this method. It is shown that, this circuit simulator will become a valuable tool for the circuit fault simulation and analysis.

Abstract: A railway is a strip-shaped corridor usually divided into multiple sections that are constructed separately. Associated construction contracts must consider scheduling. Because a railway is a continual linear structure, high-precision level surveys are needed for rail sections to connect smoothly. However, the different phases and sections of construction require multiple-level surveys, which often lead to bias in the benchmarks. Since the railway is a continuous alignment, and an inconsistent elevation system affects the civil work and subsequent track laying. This study therefore used a statistical method to eliminate inconsistencies in benchmarks. Statistics are widely used in engineering and in daily life, to solve decision making problems involving uncertainties. This study used the expected value of closing error between benchmarks as an index for recalculating level, and used the standard error of expected value as the accuracy index. Application of the proposed method using measurement data for a Taipei underground project of the Taiwan Railway Administration showed that it eliminates bias in benchmarks and provides the required accuracy for closure between adjacent points.

Abstract: To improve the design efficiency of medical robot arm, a virtual simulation system was built by making full use of the virtual simulation technology. First , a 3D model of the robot arm with five-freedom was built in Solidworks; and then, the model was imported into the dynamic simulation software RecurDyn for kinematics and dynamic simulation; at last, through the interface modular part of Matlab/Simulink and RecurDyn, medical robot arm control system was established by using Simulink module and coordinated simulation of five-freedom was successfully implemented .The simulation results indicate that the coordinated simulation system of the robot arm has preferable dynamic response characteristics and nicer locus-tracking ability.

Abstract: Force-Reflected Telepresence Teleoperation system has been widely used. Generally, force and torque sensors are installed on the robot to realize haptic perception. Control commands and force-reflected information from the robot are transmitted by communication link, such as internet. However, this structure not only brings difficulties of installation and commissioning, but also reduces the system flexibility and makes control more difficult. And it is prone to interfered in microenvironment. This paper presents a new type of energy transfer method to achieve it by power line instead of internet between the Master-slave Manipulators. This method achieves the consistency of force-reflected without using sensors to measure the conditions. In practical application, it requires to design an energy managed controller to insure the stability and obtain precision in synchronization between the master part and slave part. This paper gives the theory, the system structure and control method of force telepresence teleoperation based on power line.

Abstract: This paper introduces an improved watershed algorithm for liver image segmentation. Medical images have complicated structure and the soft tissues have deformation sometimes. To exactly conduct the following image registration or surgery navigation, the image segmentation must identify the changes quickly and accurately. Watershed algorithm has fast speed and good edge location for complex structure, but it is sensitive to noise and has the over-segmentation problem. In this paper, pre-processing and post-processing methods are proposed during watershed segmentation procedure. According to the thresholds of region area and gray difference between adjacent regions, the image noise is reduced at pre-processing stage and the over-segmented regions are merged at post-processing part. Through the experiment of two similar liver images, we can see the segmented images have clear outline and the difference of two images can be identified obviously.

Abstract: Since organizational tacit knowledge resides in the owner’s brain, finding relevant experts in the specific fields is crucial to utilize this type of knowledge. In this paper, an approach to expert finding is proposed to assist the user to find the required experts. The method adopts the multi-granularity two-tuple linguistic information to construct the expert profile, that is, to model expert’s expertise. The user query the expert based on the fuzzy linguistic information. Then, the relevant experts are ranked according to the matching degree between the expert profile and the query. Finally, a numerical example is given to illustrate the effectiveness of the proposed approach.

Abstract: This paper proposes a lightweight model as an alternative methodology of risk assessment for web applications. The assessment model presented in this paper takes into account not only the threats to the web applications but also the environments where they are hosted. STRIDE model is used as a measure to identify the threats by analyzing dataflow, data store and process presented in dataflow diagram. Moreover, DREAD is used to calculate the security risk of each threat, which is extended with the consideration of the assets’ criticalities and their application environments.

Abstract: In this paper, we propose an image-based approach for the simulation of outdoor snowy scenes. Using a snowy image as the reference, we extract the snow covered regions from the reference through a snow model and achieve the snow color information. Then the target image will get the snow color information and take on snowy appearance through a color transfer procedure. To solve the problem of different data distributions between the reference and the target in the procedure, power transform and modulus transform are employed to adjust the image data according to the snow information derived from the reference image data. The experimental results indicate this approach can simulate the snowy scenes with high quality while greatly reducing the computational complexity of simulation compared with the traditional algorithms.