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排序方式: 共有1463条查询结果,搜索用时 15 毫秒
41.
DoHyung Kim Jaeyeon Lee Ho-Sub Yoon Jaehong Kim Joochan Sohn 《The Journal of supercomputing》2013,65(1):336-352
This paper proposes a vision-based human arm gesture recognition method for human–robot interaction, particularly at a long distance where speech information is not available. We define four meaningful arm gestures for a long-range interaction. The proposed method is capable of recognizing the defined gestures only with 320×240 pixel-sized low-resolution input images captured from a single camera at a long distance, approximately five meters from the camera. In addition, the system differentiates the target gestures from the users’ normal actions that occur in daily life without any constraints. For human detection at a long distance, the proposed approach combines results from mean-shift color tracking, short- and long-range face detection, and omega shape detection. The system then detects arm blocks using a background subtraction method with a background updating module and recognizes the target gestures based on information about the region, periodical motion, and shape of the arm blocks. From experiments using a large realistic database, a recognition rate of 97.235% is achieved, which is a sufficiently practical level for various pervasive and ubiquitous applications based on human gestures. 相似文献
42.
A novel ironmaking technology is under development at the University of Utah. The purpose of this research was to determine comprehensive kinetics of the flash reduction reaction of magnetite concentrate particles by hydrogen. Experiments were carried out in the temperature range of 1423 K to 1673 K (1150 °C to 1400 °C) with the other experimental variables being hydrogen partial pressure and particle size. The nucleation and growth kinetics expression was found to describe the reduction rate of fine concentrate particles and the reduction kinetics had a 1/2-order dependence on hydrogen partial pressure and an activation energy of 463 kJ/mol. Unexpectedly, large concentrate particles reacted faster at 1423 K and 1473 K (1150 °C and 1200 °C), but the effect of particle size was negligible when the reduction temperature was above 1573 K (1300 °C). A complete reaction rate expression incorporating all these factors was formulated. 相似文献
43.
Hong Yong Sohn 《Metallurgical and Materials Transactions B》2014,45(5):1600-1602
It is argued that the term with the negative sign in the rate expression for an equilibrium-limited gas–solid reaction can be viewed as representing a lowering of the concentration driving force for the forward reaction due to equilibrium limitation. While the gas composition favors the forward reaction, the negative term may represent the local rate of the reverse reaction. When the gas composition changes significantly to the opposite side of equilibrium, however, this term as written for the forward reaction does not represent the rate of the reverse reaction. Even the reaction order with respect to the same gaseous species may become different for the reverse reaction. 相似文献
44.
The effects of different types of reducing gas on swelling and iron whisker formation during the reduction of iron oxide compacts were investigated. The compacts sintered in air at 1273 K were reduced at 1173 K in different reducing atmospheres. The results indicated that catastrophic swelling can happen in CO but not when H2 is present in the reducing gas mixture. Scanning electron microscope (SEM) micrographs showed that catastrophic swelling was caused by a large amount of long iron whiskers formed during the reduction. The presence of N2 and CO2 in CO changed the amount of long iron whiskers and its distribution, which determined the extent of swelling. 相似文献
45.
Kyoungkeun Yoo Shun-Myung Shin Dong-Hyo Yang Jeong-Soo Sohn 《Minerals Engineering》2010,23(3):219-224
Wastewater produced during recycling of spent lithium primary battery was biologically treated with Acidithiobacillus ferrooxidans to decrease the pH and metal concentration. Since the wastewater contains high concentrations of Cr, Ni, and Li, the effects of these metals on the bacterial activity in a 9 K medium were also investigated. Samples of the medium with different metal concentrations were treated, and the oxidation ratio of Fe2+ ions was measured to examine the activity of bacteria. In the treatment of simulated wastewater, the presence of Cr and Ni ions with concentrations of 8000 g m?3 and 13,000 g m?3, respectively, did not inhibit the bacterial activity, whereas the oxidation ratio of Fe2+ ions was observed to be low in the medium when Li ion was present with a concentration at 5000 g m?3. This observation suggested that at this concentration, Li ion suppressed the bacterial activity. In the case of treatment of real wastewater containing Cr, Ni, and Li, the oxidation ratio of Fe2+ to Fe3+ was observed to be low while the Fe concentration and pH decreased to 21,633 g m?3 and 1.8, respectively. Thus, the wastewater produced during the recycling of spent lithium primary batteries can be effectively treated biologically for re-circulating in the recycling process. 相似文献
46.
Kim JeongJu Sohn Ho-Seong Park Hee Seung Hsu Wei-Ting Ueda Osamnu Cho Hyung Hee 《Journal of Mechanical Science and Technology》2021,35(10):4575-4583
Journal of Mechanical Science and Technology - Recently, domestic gas turbines are primarily operated under partial loads. Hence, thermal expansion of components decreases, leading to a... 相似文献
47.
Ahn Seoyeon Nam Chanhyuk Choi Sungjin An Daekwon Kim Ingi Seo Kyungsoo Sohn Changhyun 《Journal of Mechanical Science and Technology》2021,35(5):1923-1933
Journal of Mechanical Science and Technology - In this paper, to help reduce the squeal noise produced during the braking of urban railway vehicles, the shape of the disc brake pad was investigated... 相似文献
48.
In the past, most studies into kinetic spraying technology focused on basic research, but a large portion of current research is devoted to industrial applications of the technology. To advance, however, studies about industrial applications of kinetic spraying require profound understanding of the scientific foundations of the kinetic spray process. Nevertheless, no one has yet provided a well-organized summary of the correlations among impact conditions, interface reactions, microstructural evolution, and mechanical properties across the whole field of kinetic spraying technology. This paper provides such an overview of these correlations for kinetic spraying of metals. For each correlation, the interactions between the given conditions and the material properties of the metal feedstock powder are the most influential. These interactions are so complicated that it is difficult to systematically classify all cases into certain types. Nonetheless, we try to explain and summarize the critical factors and their roles in each relationship. 相似文献
49.
We try to identify the determinants of regional variation in both exploitative and exploratory innovative competencies. Hereby, we focus on how a knowledge-creation mechanism with specialized externalities differs from one with diversified externalities. Innovative competence in the US is measured by local patenting performance; exploitative and exploratory patenting performances are distinguished by the degree of backward citation. Based on the extended knowledge-production function, including the two agglomeration externalities, our findings show that specialized externalities are associated with exploitation, while diversified externalities are positively related with both exploration and exploitation, regardless of industrial sectors. 相似文献
50.