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51.
A macroblock‐level deblocking method is proposed for H.264/AVC, in which blocking artifacts are effectively eliminated in the discrete cosine transform domain at the macroblock encoding stage. Experimental results show that the proposed algorithm outperforms conventional H.264 in terms of coding efficiency, and the bitrate saving is up to 5.7% without reconstruction quality loss. 相似文献
52.
Comparison of Two D−A Type Polymers with Each Being Fluorinated on D and A Unit for High Performance Solar Cells 下载免费PDF全文
Jea Woong Jo Seunghwan Bae Feng Liu Thomas P. Russell Won Ho Jo 《Advanced functional materials》2015,25(1):120-125
For the purpose of investigating the effect of fluorination position on D?A type conjugated polymer on photophysical and photovoltaic properties, two types of fluorinated polymere are synthesized, HF with fluorination on electron‐donating unit and FH with fluorination on electron‐accepting unit. Compared to non‐fluorinated polymer, fluorinated polymers exhibit deeper HOMO energy levels without change of bandgap and stronger vibronic shoulder in UV?visible absorption, indicating that fluorination enhances intermolecular interaction. HF with fluorinated D unit exhibits well‐developed fibril network, low bimolecular recombination and high hole mobility, which lead a high PCE of 7.10% in conventional single‐junction solar cells, which is higher than the PCE (6.41%) of FH with fluorinated A unit. Therefore, this result demonstrates that fluorination on electron‐donating unit in D?A polymers could be a promising strategy for achieving high performance polymer solar cells. 相似文献
53.
The development of decommissioning technologies, including those for evaluation of the radioactivity inventory and the radiation dose, and a site investigation plan are needed to ensure safe decommissioning. The residual radioactivity should be measured and analysed to release a site for unrestricted use. The methods used for measurement of residual radioactivity have an effect on the workers' manpower and the decommissioning cost. So the development of the measurement methods of residual radioactivity with guidelines for a radiation survey and site investigation is needed to prepare for the future decommissioning of commercial Nuclear Power plants. The major considerations and characteristics of the parameters related to the decision of measurements points have been reviewed. The methods for controlling uncertainty and techniques to determine whether the measurement results achieve the survey objectives have been established. 相似文献
54.
Dae‐Hwan Kim Seung‐Won Jung Suryanto Seung‐Jun Lee Hyo‐Kak Kim Sung‐Jea Ko 《ETRI Journal》2012,34(3):399-409
In this paper, we propose a new color histogram model for object tracking. The proposed model incorporates the color arrangement of the target that encodes the relative spatial distribution of the colors inside the object. Using the color arrangement, we can determine which color bin is more reliable for tracking. Based on the proposed color histogram model, we derive a mean shift framework using a modified Bhattacharyya distance. In addition, we present a method of updating an object scale and a target model to cope with changes in the target appearance. Unlike conventional mean shift based methods, our algorithm produces satisfactory results even when the object being tracked shares similar colors with the background. 相似文献
55.
Inyoung Kim Young Ah Song Hyun Chul Jung Jea Woo Joung Sung-Soo Ryu Jongryoul Kim 《Journal of Electronic Materials》2008,37(12):1863-1868
The microstructural characterization of inkjet-printed Ag films sintered at various conditions was carried out to analyze
the effect of microstructure on mechanical and electrical properties. As expected, the films became denser with grain growth
with increasing sintering time and temperature, which resulted in improvement in mechanical properties. However, the resistivity
of the films reached a minimum value of 3.0 μΩ cm before full densification. In order to improve the mechanical properties, pressure-assisted sintering was introduced.
As a result, inkjet-printed Ag films sintered at 250°C under 5 MPa showed a tensile strength of 550 MPa, elongation of 2.4%,
Young’s modulus of 55 GPa, and resistivity of ~3.0 μΩ cm. 相似文献
56.
Flexible Electronics: Improving Performance and Stability of Flexible Planar‐Heterojunction Perovskite Solar Cells Using Polymeric Hole‐Transport Material (Adv. Funct. Mater. 25/2016) 下载免费PDF全文
57.
This paper presents a deblocking method for video compression in which the blocking artifacts are effectively extracted and eliminated based on both spatial and frequency domain operations. Firstly, we use a probabilistic approach to analyze the performance of the conventional macroblock‐level deblocking scheme. Then, based on the results of the analysis, an algorithm to reduce the computational complexity is introduced. Experimental results show that the proposed algorithm outperforms the conventional video coding methods in terms of computation complexity while coding efficiency is maintained. 相似文献
58.
Somasundara A.A. Kansal A. Jea D.D. Estrin D. Srivastava M.B. 《Mobile Computing, IEEE Transactions on》2006,5(8):958-973
We discuss the use of mobility to enhance network performance for a certain class of applications in sensor networks. A major performance bottleneck in sensor networks is energy since it is impractical to replace the batteries in embedded sensor nodes post-deployment. A significant portion of the energy expenditure is attributed to communications and, in particular, the nodes close to the sensor network gateways used for data collection typically suffer a large overhead as these nodes must relay data from the remaining network. Even with compression and in-network processing to reduce the amount of communicated data, all the processed data must still traverse these nodes to reach the gateway. We discuss a network infrastructure based on the use of controllably mobile elements to reduce the communication energy consumption at the energy constrained nodes and, thus, increase useful network lifetime. In addition, our approach yields advantages in delay-tolerant networks and sparsely deployed networks. We first show how our approach helps reduce energy consumption at battery constrained nodes. Second, we describe our system prototype, which utilizes our proposed approach to improve the energy performance. As part of the prototyping effort, we experienced several interesting design choices and trade-offs that affect system capabilities and performance. We describe many of these design challenges and discuss the algorithms developed for addressing these. In particular, we focus on network protocols and motion control strategies. Our methods are tested using a practical system and do not assume idealistic radio range models or operation in unobstructed environments. 相似文献
59.
Tae Su Oh Hyun JeongYong Seok Lee Tae Hoon SeoAh Hyun Park Hun KimKang Jea Lee Mun Seok JeongEun-Kyung Suh 《Thin solid films》2011,519(8):2398-2401
We investigated defect structures in the GaN film grown on a convex patterned sapphire substrate (CPSS) to determine the origin of structural improvement by transmission electron microscopy (TEM) and laser confocal scanning microscopy (LCSM). From the TEM results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the curved slant region of the convex pattern; they converged at the top of the convex patterned region by staircase-upward propagation. This scenario seems to effectively prevent TDs from vertical propagation in the trench region. The photoluminescence mapping and spectra obtained by LCSM are consistent with these results from TEM observations. The generation of staircase-like TDs relates to the formation of a terraced surface during the growth, and suggests a probable mechanism that changes the propagation direction of TDs via the curved surface of the CPSS. The lateral growth and staircase-upward propagation of TDs are major factors on structural improvement of the GaN film grown on CPSS. 相似文献