Fast and scalable lock methods for video coding on many-core architecture

Many-core processors are good candidates for speeding up video coding because the parallelism of these applications can be exploited more efficiently by the many-core architecture. Lock methods are important for many-core architecture to ensure correct execution of the program and communication between threads on chip. The efficiency of lock method is critical to overall performance of chipped many-core processor. In this paper, we propose two types of hardware locks for on-chip many-core architecture, a centralized lock and a distributed lock. First, we design the architectures of centralized lock and distributed lock to implement the two hardware lock methods. Then, we evaluate the performance of the two hardware locks and a software lock by quantitative evaluation micro-benchmarks on a many-core processor simulator Godson-T. The experimental results show that the locks with dedicated hardware support have higher performance than the software lock, and the distributed hardware lock is more scalable than the centralized hardware lock.     

基于深度学习的运动目标交接算法

针对多摄像机非重叠视域下存在的运动目标不连续性和不确定性的问题, 提出一种基于深度学习的运动行人目标的交接算法. 首先基于深度卷积神经网络构建人脸特征提取模型, 对人脸特征提取模型进行训练, 获得精确的人脸特征. 然后比较两种常用的相似度度量方法, 选择其中一种更适合的相似度度量方法, 以完成最优的人脸匹配过程, 提高人脸匹配的准确率. 最后通过对不同摄像机下的人脸进行特征匹配找到最匹配的人脸, 实现运动目标的交接. 实验表明, 深度神经网络可以减少运动目标丢失的概率, 准确地提取到运动目标的人脸特征, 有效完成多摄像机下运动目标的交接跟踪任务.     

An adaptive balance optimization algorithm and its engineering application

The policy of balance between exploration capability and exploitation capability directly affects the solution performance of the meta-heuristic algorithm in a limited time. In order to better balance the exploration and exploitation capabilities of the algorithm and meet the solution requirements of complex real-world problems, the adaptive balance optimization algorithm (ABOA) is proposed in this paper. The algorithm consists of a global search phase (GSP) and a local search phase (LSP) and is controlled by a fixed parameter. ABOA not only considers the balance of exploration and exploitation capabilities of the algorithm throughout the whole iterative process but also focuses on the balance of exploration and exploitation in both GSP and LSP. The search in both phases is focused around the respective search centers from outside to inside. ABOA balances the exploration and exploitation capabilities of the algorithm throughout the search process by two adaptive policies: changing the search area and changing the search center. Fifty-two unconstrained benchmark test functions were employed to evaluate the performance of ABOA. The results of ABOA were compared with nine excellent optimization algorithms available in the literature. The statistical results and Friedman test showed that ABOA was significantly competitive. Finally, the results of the examined engineering design problems showed that ABOA can solve the constrained optimization problem better compared to other methods.     

Influence of Sb-doping on dielectric properties of NaCu3Ti3TaO12 ceramics and relevant mechanism(s)

A series of NaCu₃Ti₃Ta_1−xSb_xO₁₂ ceramics were prepared by the conventional solid-state reaction technique, and their dielectric properties, crystalline structures, microstructures and complex impedance were investigated systematically. All the ceramics show the main phases of perovskite-related crystallographic structure, and their dielectric properties change significantly with the increasing Sb-doping. All these ceramics exhibit giant dielectric-permittivity properties, and impedance spectroscopy analysis reveals that NaCu₃Ti₃Ta_1−xSb_xO₁₂ ceramics are electrically heterogeneous and composed of insulating grain boundaries and semiconducting grains. Moreover, CuO secondary phase and Cu²⁺/Cu¹⁺, Ti⁴⁺/Ti³⁺, Sb⁵⁺/Sb³⁺ and Ta⁵⁺/Ta³⁺ aliovalences are found to exist in NaCu₃Ti₃Ta_1−xSb_xO₁₂ ceramics through XRD, EDS and XPS analysis. Therefore, CuO segregation and aliovalences of metal ions were suggested to contribute greatly to the internal barrier layer capacitance effect formation in NaCu₃Ti₃Ta_1−xSb_xO₁₂ ceramics. Furthermore, Sb-doping could decrease the tanδ of NaCu₃Ti₃Ta_1−xSb_xO₁₂ ceramics at low frequencies, and the reason was discussed.     

Studies on preparation and performances of carbon aerogel electrodes for the application of supercapacitor

Carbon aerogel was prepared by the polycondensation of resorcinol (R) with formaldehyde (F), and sodium carbonate was added as a catalyst (C). Physical properties of carbon aerogel were characterized by infrared spectrometer (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that carbon aerogel is an amorphous material with a pearly network structure, and it consists of one or two diffuse X-ray peaks. The results of cyclic voltammetry indicated that the specific capacitance of a carbon aerogel electrode in 6 M KOH electrolyte was approximately 110.06 F g⁻¹. Through the galvanostatic charge/discharge measurement, it was found that the electrode is stable in KOH electrolyte, the maximum capacitance of the supercapacitor with carbon aerogel as the electrode active material was 28 F g⁻¹. Besides, the supercapacitor has long cycle life. Thus, it was thought that the carbon aerogel is an excellent electrode material for a supercapcitor.     

Hybrid ZnO-organic semiconductor interfaces in photodetectors: A comparison of two near-infrared donor-acceptor copolymers

Hybrid organic-inorganic photodiode interfaces have gained significant interest due to their unique physical properties such as mechanical flexibility and high photosensitivity. Two diketopyrrolopyrrole (DPP)-based donor-acceptor copolymers with different backbone conformations are characterized in an inverted non-fullerene photodiode architecture using ZnO nano-patterned films as the electron transport layer. The DPP copolymer with a thienothiophene unit (PBDT-TTDPP) is more planar and rigid compared to the DPP system with a thiophene unit connecting the donor and acceptor moieties within the monomer (PBDT-TDPP). The hybrid interfaces were optimized by using poly(3-hexylthiophene) (P3HT) as the p-type layer for monitoring the critical thickness and morphology of the ZnO layer. The maximum photoresponsivity from a P3HT:ZnO photodiode was found to be 56 mA/W. The photoresponsivity of PBDT-TTDPP:ZnO photodiodes were found to be more than two orders of magnitude higher than PBDT-TDPP:ZnO photodiodes, which is attributed to an enhanced transport of carriers due to the planar backbone conformation of the PBDT-TTDPP copolymer. Capacitance-voltage measurements from hybrid Schottky barrier interfaces further shed light into the nature of photocarriers and device parameters. First-principles time-dependent density-functional theoretical calculations yield a higher absorptivity for the PBDT-TTDPP dimer compared to PBDT-TDPP.     

基于改进MDNet的视频目标跟踪算法

目标跟踪算法面对的突出问题之一是正负样本不均衡, 正样本极度相似. 针对跟踪更新过程中正样本不丰富的问题, 本文基于多域卷积神经网络(MDNet)算法, 提出了一种改进MDNet的视频目标跟踪算法, 首先改进原算法中候选框的选取策略, 提出了一种基于候选框置信度与坐标方差阈值判断相结合的模型更新方法, 其次将原算法的交叉熵损失函数改进为效果更好的focal loss损失函数. 实验结果表明在相同实验环境下本文算法相较于MDNet算法在跟踪准确率和成功率上均有明显提高.     

I.r. studies on the acidity of dealuminated Y zeolite with different probe molecules

Dealuminated HY zeolites (D-HY), which are partly reexchanged by La ions (D-LaHY), show two i.r. bands at 3625 cm⁻¹ (high frequency) and 3550 cm⁻¹ (low frequency). In contrast to the findings in D-HY and nondealuminated La-exchanged Y zeolite (LaHY), the LF band of D-LaHY is considerably affected by the adsorption of butadiene, in connection with a strongly increased coking. Sorption experiments with pyridine and ammonia confirm the OH groups belonging to the LF band to be acidic and accessible even to pyridine. This can be further confirmed by an HD exchange reaction with C₆D₆ at room temperature.     

基于粒子群优化的室内动态热舒适度控制方法

针对预测平均投票数(predicted mean vote,PMV)值在舒适区和节能区之间周期性交替变化的控制方法,提出了基于PMV的动态舒适度冷/热抱怨模型和能耗模型.基于此模型,根据用户设定的舒适和节能两者的协调关系,运用改进的多目标离散粒子群优化算法,得出动态舒适度控制系统输入参数的寻优方法.该方法只需实时测量热环境和居住者热感觉数据,不需建立热环境物理解析模型,普适性强.实验证明了上述控制方法的有效性,该方法可实现动态舒适度的最优控制.