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1.
A number of studies have examined virtual worlds, which can facilitate knowledge sharing, education, and enjoyment, among others. However, no study has provided an insightful research model for evaluating virtual worlds. This study suggests that users’ identification with virtual communities and avatars plays a critical role in the construction of attractive virtual worlds. The proposed model measures the level of the user’s identification with virtual communities, through which the user builds his or her trust in other community members. In addition, the study suggests that users’ identification with avatars is an important element of their satisfaction with virtual worlds. The results indicate that users’ identification with virtual communities as well as avatars can enhance their efficacy and trust and thus facilitate their sustained use of virtual services. The results have important theoretical and practical implications. 相似文献
2.
Khan Abdul Manan Yun Deok-won Zuhaib Khalil Muhammad Iqbal Junaid Yan Rui-Jun Khan Fatima Han Changsoo 《International Journal of Control, Automation and Systems》2017,15(2):802-814
International Journal of Control, Automation and Systems - In this paper, we have addressed two issues for upper limb assist exoskeleton. 1) Estimation of Desired Motion Intention (DMI); 2) Robust... 相似文献
3.
The lifetime of porous low-k dielectrics has been observed to degrade as a function of porosity. This paper demonstrates that pores disturb the electric field within a dielectric through finite element simulation. The disturbance of electric field extends beyond the pore itself. A model of charge transport has been developed to demonstrate the sensitivity of leakage currents in a dielectric to porosity. 相似文献
4.
Seungnam Yu Changhwan Choi Seungyeol Lee Jeongyeob Lee Changsoo Han 《Journal of Mechanical Science and Technology》2011,25(4):1051-1060
This paper presents a servo motor selection technique for a mobile mine detection system which is operated in the field condition.
As a first step, mine detection sensor should follow the earth profile while maintaining a constant distance to the earth
surface. In order to acquire a reasonable manipulator trajectory and its required torque, a kind of modeling technique is
devised to remove the unwanted fluctuations in the earth data. Then, Straete et al.’s normalization method is adopted and
is improved to select the adequate actuator for each joint of manipulator. The improvements are as follows: First, an equivalent
output power lines are plotted at the same load curve, which gives another selection criterion. Second, a temperature based
criterion is proposed for the continuous limit, which estimates the steady state winding temperature of a motor, and can be
used to determine a suitable motor and gear ratio. This formulation gives not only the selection of a motor and gear ratio,
but also gives the estimated operating temperature. Finally, realized system is verified through the basic performance test. 相似文献
5.
An advanced regression scheme is proposed to analyze fine leak batch testing data of multiple MEMS packages. The scheme employs the forward-stepwise regression method to infer the information of leaky packages from a batch test data. The analysis predicts the number of leaky packages and the true leak rate of each leaky package in a progressive manner. The scheme is implemented successfully using an actual batch test data obtained from wafer-level hermetic MEMS packages. An error analysis is followed to define the applicable domain of the scheme. Advanced formulations are also suggested to extend the applicable domain. 相似文献
6.
Changsoo Jang Geun Sik Ahn Yung Joon Kim Dong Ok Kwak Seong Woon Booh Jae Ok Kim 《Electronics Packaging Manufacturing, IEEE Transactions on》2003,26(1):46-53
The joint structure of a transducer horn-holder assembly for a wire bonder was examined through finite element contact analysis. Three-dimensional modeling and analysis was carried out to survey the internal physics of this structure and to verify the accuracy of a proposed computation relative to measurement. After validation, a two-dimensional model was built to conduct parametric studies and improve the efficiency and speed of the computation. Several factors such as boundary conditions, modeling boundary, and mesh density, were considered to obtain consistency with the three-dimensional analysis. Arc angle and the position of each holder boss were chosen as design parameters. A designed computation approach was applied for efficiency in computation. As a result, a guideline for holder boss design was suggested, and the main factors and their influence on stress concentration in the transducer horn were surveyed. 相似文献
7.
Nonlinear compensation techniques are becoming increasingly important. We present a new Volterra-based predistorter, which utilizes the indirect learning architecture to circumvent a classical problem associated with predistorters, namely that the desired output is not known in advance. We utilize the indirect learning architecture and the recursive least square (RLS) algorithm. Specifically, we propose an indirect Volterra series model predistorter which is independent of a specific nonlinear model for the system to be compensated. Both 16-phase shift keying (PSK) and 16-quadrature amplitude modulation (QAM) are used to demonstrate the efficacy of the new approach 相似文献
8.
Monitoring thiocyanate-degrading microbial community in relation to changes in process performance in mixed culture systems near washout 总被引:3,自引:0,他引:3
Changes in microbial community structure, associated with changes in process performance, were investigated with respect to the sludge retention time (SRT) in bioreactors treating thiocyanate. Among the seven reactors operated at 0.8-3.0 d SRTs, respectively, the reactor at 2.0 d SRT displayed the maximal thiocyanate removal rate of 240.2mg/L/d. However, the thiocyanate removal efficiency suddenly decreased from 96.1% to 43.1% when the SRT was reduced from 2.0 to 1.8d, corresponding to a 50.1% drop in the removal rate. Microbial communities in the reactors operated at short SRTs, near washout, were analyzed by denaturing gradient gel electrophoresis (DGGE) based on bacterial 16S rRNA genes. All band sequences recovered were assigned to two phyla, Proteobacteria and Bacteriodetes. A Thiobacillus-like microorganism was commonly detected in all the reactors and is suggested to be the main organism responsible for thiocyanate decomposition. Several DGGE band sequences were closely related to the environmental clones detected in environments rich in sulfur and/or nitrogen compounds. Statistical analysis of the DGGE profiles demonstrated that the structure of thiocyanate-degrading communities, as well as the process performance, changed with change in SRT. The microbial community profiles were not always more closely related to those at similar SRT than those at less similar SRT on the non-metric multidimensional scaling (NMDS) map. This was also supported by clustering analysis. These results were contrary to the general notion that the community structures in continuous systems will be controlled by the washout of microbial populations. Our experimental results suggest that the structure of a microbial thiocyanate-degrading community at a given SRT would not be determined only by the washout effect. 相似文献
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10.
Hyo-gon Kim Sangdeok Park Changsoo Han 《Journal of Mechanical Science and Technology》2014,28(11):4361-4367
When a linear actuator is used for rotation motion by a knee joint of an exoskeleton, the specifications of the joint range of motion (ROM) and joint torque change according to how the linear actuator are attached. Moreover, while the linear actuator generates a constant amount of force, the joint torque generated by the actuator changes according to the joint angle, which causes the torque contraction. This makes it difficult to meet the required torque and ROM for walk and stand-to-sit and sit-to-stand (STS) motions while carrying a load. To solve these problems we propose a novel knee joint for an exoskeleton with good energy efficiency during walk and STS motions while carrying a load. The mechanism is composed of a four-bar linkage and an elastic element. Based on an analysis of human motion, the design variables of the joint were optimized and the feasibility of the optimized variables was verified through the simulation. The findings from the simulation results suggest that combining a four-bar linkage with a linear actuator allows a large ROM and good torque performance of the knee joint for walk and STS motions. Moreover, the energy efficiency can be improved because the spring mounted parallel to the actuator can store the energy dissipated as negative work and recycle the energy as positive work. 相似文献