Fast Linearized Bregman Method for Compressed Sensing

( Zhenzhen Yang ),( Zhen Yang ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.9

In this paper, a fast and efficient signal reconstruction algorithm for solving the basis pursuit (BP) problem in compressed sensing (CS) is proposed. This fast linearized Bregman method (FLBM), which is inspired by the fast method of Beck et al., is based on the fact that the linearized Bregman method (LBM) is equivalent to a gradient descent method when applied to a certain formulation. The LBM requires O(1/ε) iterations to obtain an -optimal solution while the FLBM reduces this iteration complexity to and requiring almost the same computational effort on each iteration. Our experimental results show that the FLBM can be faster than some other existing signal reconstruction methods.

Effect of Chemical Admixtures on Setting Time, Fluidity and Mechanical Properties of Phosphorus Gypsum Based Self-Leveling Mortar

Zhenzhen Zhi,Jian Huang,Yanfei Guo,Siwen Lu,Baoguo Ma 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

Phosphorus Gypsum (PG) based Self-Leveling mortar (GSL) is a green and efficient material for floor construction. Its hydration kinetics, rheology property and their effect on mechanical strength of hydrated GSL were crucial to its final application. This study analyzed the effect on setting time of three retarders, namely Protein Salt (PS), Citric Acid (CA), and Sodium Tripolyphosphate (STPP). The fluidity of GSL was investigated individually using three different types of superplasticizer, namely naphthalene (FDN), polycarboxylate (PCE) and melamine (MSF). Finally, the effect of these chemical admixtures on mechanical properties of GSL hardened was examined. Results showed that the optimal contents of PS were 0.1%-0.15% by weight. With 0.1% PS, setting time of GSL retarded to 80min. To reach a maximum fluidity of GSL to 350mm, the optimal contents of PCE, MSF and FDN were 0.2%, 0.6% and 1.0% respectively and corresponding compressive strength of GSL were 54.25MPa, 53MPa and 52.25MPa. Suggesting PCE is the most effective dispersant in PG based GSL system.

Visualizing Polymer Spherulites in 3D

Zhenzhen WEI,Pantea KAZEMI,Hina SABA,Goran UNGAR,Ruibin ZHANG 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

The ethics of COVID-19 clinical trials: New considerations in a controversial area

Zhenzhen Han,Junting Wang,Kai Zhang,Qilin Tang 한국한의학연구원 2020 Integrative Medicine Research Vol.9 No.3

Influence of Restricted Grazing Time Systems on Productive Performance and Fatty Acid Composition of Longissimus dorsi in Growing Lambs

Zhenzhen Wang,Yong Chen,Hailing Luo,Xueliang Liu,Kun Liu 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.8

Fifty 3-month-old male Tan lambs (similar in body weight) were divided into 5 groups to investigate the effects of different restricted pasture grazing times and indoor supplementation on the productive performances and fatty acid composition of the intramuscular fat in growing lambs. The lambs grazed for different periods of time (12 h/d, 8 h/d, 4 h/d, 2 h/d, and 0 h) and received various amounts of supplementary feedings during the 120-day trial. Pasture dry matter intake (DMI), total DMI, average daily gains and the live body weights of the lambs were measured during the experiment. The animals were slaughtered at the end of the study, their carcass traits were measured, and their longissimus dorsi muscles were sampled to analyze the intramuscular fat (IMF) content and fatty acid profiles. The results indicated that the different durations of grazing and supplementary feedings affected the animal performances and the composition of fatty acids. Grazing for 8 h/d or 2 h/d with the corresponding supplementary concentrate resulted in lambs with higher body weights, carcass weights and IMF contents. Lambs with longer grazing times and less concentrate accumulated more healthy fatty acids such as conjugated linoleic acid and n-3 polyunsaturated fatty acid and had higher n-3/n-6 ratios. Overall, a grazing allowance of 8 h/d and the corresponding concentrate was recommended to maintain a high quantity and quality of lamb meat.

A Virtual-Queue based Backpressure Scheduling Algorithm for Heterogeneous Multi-Hop Wireless Networks

( Zhenzhen Jiao ),( Baoxian Zhang ),( Jun Zheng ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.12

Backpressure based scheduling has been considered as a promising technique for improving the throughput of a wide range of communication networks. However, this scheduling technique has not been well studied for heterogeneous wireless networks. In this paper, we propose a virtual-queue based backpressure scheduling (VQB) algorithm for heterogeneous multi-hop wireless networks. The VQB algorithm introduces a simple virtual queue for each flow at a node for backpressure scheduling, whose length depends on the cache size of the node. When calculating flow weights and making scheduling decisions, the length of a virtual queue is used instead of the length of a real queue. We theoretically prove that VQB is throughput-optimal. Simulation results show that the VQB algorithm significantly outperforms a classical backpressure scheduling algorithm in heterogeneous multi-hop wireless networks in terms of the packet delivery ratio, packet delivery time, and average sum of the queue lengths of all nodes per timeslot.

Predominant D1 Receptors Involvement in the Over-expression of CART Peptides after Repeated Cocaine Administration

Zhenzhen Hu,오은혜,정연복,홍진태,오기완 대한약리학회 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.2

The aim of this study was to investigate the involvement of dopaminergic receptors (DR) inbehavioral sensitization, as measured by locomotor activity, and the over-expression of cocaine- andamphetamine-regulated transcript (CART) peptides after repeated administration of cocaine in mice. Repeated administrations of cocaine induced behavioral sensitization and CART over-expression inmice. The levels of striatal CART mRNA were significantly increased on the 3rd day. CART peptideswere over-expressed on the 5th day in the striata of behaviorally sensitized mice. A higher proportionof CART+ cells in the cocaine-treated mice were present in the nucleus accumbens (NAc) shell than inthe dorsolateral (DL) part of caudate putamen (CP). The concomitant administration of both D1R andD2R antagonists, SCH 23390 (D1R selective) and raclopride (D2R selective), blocked cocaine inducedbehavioralsensitization, CART over-expression, and cyclic adenosine 5’-monophosphate (cAMP)/ proteinkinase A (PKA)/phospho-cAMP response element-binding protein (pCREB) signal pathways. SCH 23390more predominantly inhibited the locomotor activity, CART over-expression, pCREB and PKA activitythan raclopride. Cocaine induced-behavioral sensitization was also attenuated in the both D1R andD2R knockout (KO) mice, respectively. CART over-expression and activated cAMP/PKA/pCREB signalpathways were inhibited in the D1R-KO mice, but not in the D2R-KO mice. It is suggested thatbehavioral sensitization, CART over-expression and activated cAMP/PKA/pCREB signal pathwaysinduced by repeated administration of cocaine could be more predominantly mediated by D1R.

Effect of Mg Content on the Damping Behavior of Al–Mg Alloys

Zhenzhen Li,Hongge Yan,Jihua Chen,Weijun Xia,Bin Su,Lu Zhao,Min Song 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

This article investigated the effect of Mg content (4.5, 6.5 and 9.2, in wt%) on the damping capacities of Al–Mg alloys. The results indicate that the damping behavior can be divided into three regions. Region I refers to the low strain amplituderegion (ε < 5 × 10−5), where the damping capacity decreases with increasing the Mg content and has almost no relation withthe strain amplitude. Region II is the middle strain amplitude region (5 × 10−5 < ε < 8 × 10−4), where the damping capacityincreases rapidly with the strain. Region III refers to the high strain amplitude region (8 × 10−4 < ε < 2 × 10−3), where thedamping capacity remains constant and is independent of the strain when the strain is high enough, but increases with the Mgcontent. The damping values Q−1 of Al–4.5Mg, Al–6.5Mg and Al–9.2Mg alloys are 0.01501 ± 0.00032, 0.01633 ± 0.00032and 0.01862 ± 0.00119 at the strain of 1 × 10−3, respectively. The damping capacity in Region I is mainly determined bythe lattice distortion caused by Mg addition and the restoring force caused by pinning points and Suzuki segregation. Theextended dislocations break away from the pinning effect of Mg atoms and become moveable in Region II, and the movementof extended dislocations is the dominant damping mechanism in Region III.

Mitigation and Mechanism of Tin Whisker on Micro-bumps by Hard and Soft Underfills

Zhenzhen Shan,Ke Lin,Anmin Hu,Ming Li 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.6

It is the first time that the mitigation and mechanism of tin whisker on micro-bumps by different types of underfills are investigated under high temperature and humidity (55 ℃/88% RH) storage. Hard epoxy, soft silicone and polyurethane are selected as underfills to spin-coat the 10 μm-diameter and 20 μm-pitch Cu/Ni/SnAg micro-bumps. After six-month storage, underfills exhibite a good mitigation effect despite the surface decomposition, delamination, cracks and voids in varying degrees. Compared with the micro-bumps without underfill, the probability of whisker or hillock and oxidation or corrosion in micro-bumps is reduced by up to 66% and 96%, respectively. Based on the statistics and characterization results, the mitigation mechanism of tin whisker by underfills is proposed. The diameter and critical length of tin whisker are discussed as well to estimate its buckle or penetrate growth. Besides, several underfills failures are summarized. The findings are of great significance to the study of tin whisker mitigation on micro-bumps and provide insights into the reliability of advanced packaging.

Brain MR Multimodal Medical Image Registration Based on Image Segmentation and Symmetric Self-similarity

( Zhenzhen Yang ),( Nan Kuang ),( Yongpeng Yang ),( Bin Kang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.3

With the development of medical imaging technology, image registration has been widely used in the field of disease diagnosis. The registration between different modal images of brain magnetic resonance (MR) is particularly important for the diagnosis of brain diseases. However, previous registration methods don't take advantage of the prior knowledge of bilateral brain symmetry. Moreover, the difference in gray scale information of different modal images increases the difficulty of registration. In this paper, a multimodal medical image registration method based on image segmentation and symmetric self-similarity is proposed. This method uses modal independent self-similar information and modal consistency information to register images. More particularly, we propose two novel symmetric self-similarity constraint operators to constrain the segmented medical images and convert each modal medical image into a unified modal for multimodal image registration. The experimental results show that the proposed method can effectively reduce the error rate of brain MR multimodal medical image registration with rotation and translation transformations (average 0.43mm and 0.60mm) respectively, whose accuracy is better compared to state-of-the-art image registration methods.