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Hybrid orthogonal and non-orthogonal pilot distribution based channel estimation in massive MIMO system

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Journal of Systems Engineering and Electronics 2018年第5期29卷 881-898页

作者： ZHANG Ruoyu ZHAO Honglin ZHANG Jiayan JIA Shaobo Communication research Center Harbin Institute of Technology

How to obtain accurate channel state information(CSI)at the transmitter with less pilot overhead for frequency division duplexing(FDD) massive multiple-input multiple-output(MIMO)system is a challenging issue due to the large number of antennas. To reduce the overwhelming pilot overhead, a hybrid orthogonal and non-orthogonal pilot distribution at the base station(BS),which is a generalization of the existing pilot distribution scheme,is proposed by exploiting the common sparsity of channel due to the compact antenna arrangement. Then the block sparsity for antennas with hybrid pilot distribution is derived respectively and can be used to obtain channel impulse response. By employing the theoretical analysis of block sparse recovery, the total coherence criterion is proposed to optimize the sensing matrix composed by orthogonal pilots. Due to the huge complexity of optimal pilot acquisition, a genetic algorithm based pilot allocation(GAPA) algorithm is proposed to acquire optimal pilot distribution locations with fast convergence. Furthermore, the Cramer Rao lower bound is derived for non-orthogonal pilot-based channel estimation and can be asymptotically approached by the prior support set, especially when the optimized pilot is employed.

关键词： massive multiple-input multiple-output(MIMO) frequency division duplexing(FDD) compressed sensing hybrid pilot distribution genetic algorithm based pilot allocation(GAPA)

Endoscopic resection using band ligation for esophageal SMT in less than 10mm

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World Journal of Gastroenterology 2015年第10期21卷 2982-2987页

作者： Joung Boom Hong Cheol Woong Choi Hyung Wook Kim Dae Hwan Kang Su Bum Park Su Jin Kim Dong Jun Kim Department of Internal Medicine Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital

AIM:To evaluate the safety and feasibility of endoscopic resection using band ligation(EMR-B) for the diagnostic and therapeutic removal of tumors located in the esophageal subepithelial region having originated from the ***:From May 2009 to September 2014,after medical chart and endoscopic ultrasonography report review,a total of 15 esophageal tumors located in the submucosal layer were resected by *** symptom,location,pathology,complete resection rate,incidence of complications,incidence of minor complication,size,length of procedures time and follow up months were *** evaluate local recurrence at the resection site,periodic follow-up endoscopic examination was undertaken in all of the *** first endoscopic examination was performed about 6 mo after the endoscopic ***,the endoscopic follow up were scheduled ***:The mean age was 50.3 ± 9.67 *** mean tumor size was 6.93 ± 3.15 mm and most of the lesions size was between 5-10 mm in diameter(10/15,66.6%).In all patients,endoscopic en bloc resection was *** one patient,the vertical margin was *** mean procedural time was 8.86 ± 3.66 *** all patients,no evidence of severe complications such as perforation or bleeding *** complications such as chest pain(2/15,13.3%) and heartburn(3/15,13.3%) were reported but they symptoms were controlled by proton pump inhibitors,ulcermin and/or *** assessments of the removed specimens revealed 10 granular cell tumors(66.6%),4 leiomyomas(16.6%) and one lipoma(6.6%).No recurrence was observed during the mean follow up period of 45 ± 3.5 mo(range:5-64 mo).CONCLUSION:EMR-B might be considered safe and effective for the diagnosis and treatment of lesions measuring less than 10 mm in diameter.

关键词： Band ligation Endoscopic mucosal resection Esophag

Hexapedal Robotic Platform for Amphibious Locomotion on Ground and Water Surface

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Journal of Bionic Engineering 2016年第1期13卷 39-47页

作者： HyunGyu Kim DongGyu Lee Yanheng Liu Kyungmin Jeong TaeWon Seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea Nuclear convergence technology Div. Korea Atomic Energy Research Institute Daejeon 305-353 Republic of Korea

Bio-inspiration is a starting point from which to design engineering products by learning the secrets of living creatures. We present the design, analysis, and experimental results of a robotic platform inspired by the basilisk lizard, which is well known for its ability to run on water surface. The goal is to develop a robotic platform for amphibious locomotion on ground and water using a single configuration. A tripod gait is achieved with a hexapedal configuration and four-bar-based repeated motion of the legs. The hexapedal configuration is empirically proven to have an advantage in terms of rolling stability on water. On ground, the tripod gait can satisfy the requirements of static stability to make the center of gravity and center of pressure occur at the same position. The footpad design was determined based on an empirical study of the rolling stability and lifting force. The theoretical background and experimental results are presented to validate the ability of the proposed design to run on water and on the ground.

关键词： amphibious locomotion bio-inspiration hexapedal empirical study water-running robot

Analysis and Experiment on the Steering Control of a Water-running Robot Using Hydrodynamic Forces

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Journal of Bionic Engineering 2017年第1期14卷 34-46页

作者： HyunGyu Kim Kyungmin Jeong TaeWon Seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea Nuclear convergence technology Division Korea Atomic Energy. Research Institute Daejeon 305-353 Republic of Korea

Steering is important for the high maneuverability of mobile robots. Many studies have been performed to improve the maneuverability using a tail. The aim of this research was to verify the performance of a water-running robot steering on water using a tail. Kinematic analysis was performed for the leg mechanism and the interaction forces between the water and the feet to calculate the propulsive drag force of the water. This paper suggests a simplified planar two-link rigid body model to determine the dynamic performance of the robotic platform with respect to the effect of the tail＇s motion. Simulations based on a dynamic model were performed by applying a range of motions to the tail. In addition, a simulation with a Bang-bang controller was also performed to control the main frame＇s yawing locomotion. Finally, an experiment was conducted with the controller, and the simulation and experimental results were compared. These results can be used as a guideline to develop a steerable water-running robot.

关键词： basilisk lizard water-running robot steering Static Tail (ST) Dynamic Tail (DT) planar two-link rigid body

A facile synthesis of hierarchical Sn3O4 nanostructures in an acidic aqueous solution and their strong visible- light-driven photocatalytic activity

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Nano research 2015年第11期8卷 3553-3561页

作者： Hui Song Su-Young Son Seul Ki Kim Gun Young Jung School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST) Gwangju 500-712 Republic of Korea Carbon convergence Materials research Center Institute of Advanced Composite Materials Korea Institute of Science and Technology (KIST) Jeollabuk-do 565-905 Republic of Korea

Hierarchical tin（Ⅲ） oxide, Sn3O4, nanospheres were synthesized via hydrothermal reaction under strongly acidic ambient conditions. The morphology of Sn3O4 varied with decreasing pH. The prickly SnaO4 nanospheres changed into SnaO4 nanospheres covered with single-crystalline nanoplates having a high BET surface area of ca. 55.05 m^2·g^-1 and a band gap of ca. 2.25 eV. Small amounts （0.05 g） of the hierarchical Sn3O4 nanostructures completely decomposed a 30% methyl orange （MO） solution in 100 mL deionized water within 15 min under one sun condition （UV ＋ visible light）. The Sn3O4 photocatalyst exhibited a fast decomposition rate of 1.73 ×10^-1 min^-1, which is a 90.86% enhancement relative to that of the commercially available P25 photocatalyst. The high photocatalytic activity of the hierarchical Sn3O4 nanostructures is attributed to its ability to absorb visible light and its high surface-to-volume ratio.

关键词： Sn3O4 hierarchical structure hydrothermal morphology engineering photocatalyst

Simple-structured hydrophilic sensors for sweat uric acid detection with laser-engraved polyimide electrodes and cellulose paper substrates

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Chinese Chemical Letters 2024年第3期35卷 443-448页

作者： Linhe Xu Xueshan Hu Shuang Zhou Ze Zhang Junxian Zhang Chao Li Daxian Zuo Hao Liu Gang Chen Jiayu Wan Jinsong Tao State Key Lab of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China future Battery research Center Global Institute of Future TechnologyShanghai Jiao Tong UniversityShanghai 200240China

Accurate detection of uric acid(UA)is crucial for diagnosing gout,yet traditional sweat-based UA sensors continue to face challenges posed by complex and costly electrode fabrication methods,as well as weakly hydrophilic ***,we designed and developed simple,low-cost,and hydrophilic sweat UA detection sensors constructed by carbon electrodes and cellulose paper *** carbon electrodes were made by carbonized polyimide films through a simple,one-step laser engraving *** electrodes are porous,possess a large specific surface area,and are flexible and *** substrates were composed of highly hydrophilic cellulose paper that can effectively collect,store,and transport *** constructed electrodes demonstrate high sensitivity of 0.4μA Lμmol^(-1)cm^(-2),wide linear range of 2–100μmol/*** addition,our electrodes demonstrate high selectivity,excellent reproducibility,high flexibility,and outstanding stability against mechanical bending,temperature variations,and extended storage ***,our sensors have been proven to provide reliable results when detecting UA levels in real sweat and on real human *** envision that these sensors hold enormous potential for use in the prognosis,diagnosis,and treatment of gout.

关键词： Laser-engraved carbon Polyimide Cellulose paper Hydrophilicity Sweat uric acid

Restoration of the JPEG Maximum Lossy Compressed Face Images with Hourglass Block-GAN

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Computers, Materials & Continua 2024年第3期78卷 2893-2908页

作者： Jongwook Si Sungyoung Kim Department of Computer AI convergence Engineering Kumoh National Institute of TechnologyGumi39177Korea Department of Computer Engineering Kumoh National Institute of TechnologyGumi39177Korea

In the context of high compression rates applied to Joint Photographic Experts Group(JPEG)images through lossy compression techniques,image-blocking artifacts may *** necessitates the restoration of the image to its original *** challenge lies in regenerating significantly compressed images into a state in which these become ***,this study focuses on the restoration of JPEG images subjected to substantial degradation caused by maximum lossy compression using Generative Adversarial Networks(GAN).The generator in this network is based on theU-Net *** features a newhourglass structure that preserves the characteristics of the deep *** addition,the network incorporates two loss functions to generate natural and high-quality images:Low Frequency(LF)loss and High Frequency(HF)*** loss uses a pretrained VGG-16 network and is configured using a specific layer that best represents *** can enhance the performance in the high-frequency *** contrast,LF loss is used to handle the low-frequency *** two loss functions facilitate the generation of images by the generator,which can mislead the discriminator while accurately generating high-and low-frequency ***,by removing the blocking effects frommaximum lossy compressed images,images inwhich identities could be recognized are *** study represents a significant improvement over previous research in terms of the image resolution performance.

关键词： JPEG lossy compression restoration image generation GAN

Synthetic Turbulence Constructed by Self-Learning Fractal Interpolation

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Chinese Physics Letters 2012年第10期29卷 125-128页

作者： WANG Yan-Zhi ZHANG Zhi-Xiong SHI Yi-Peng SHE Zhen-Su State Key Laboratory of Turbulence and Complex Systems and College of Engineering Peking UniversityBeijing 100871 Beijing Aeronautical Science and technology research institute of COMAC future Science&technology Park Changping DistrictBeijing 102211

A self-learning fractal interpolation algorithm to construct synthetic fields with statistical properties close to real turbulence is *** from our previous work[***.E 84(2011)026328,82(2010)036311],the position mapping and stretching factors between the adjacent large and small scales are learned from the initial *** this method,a turbulence-like field with K41 spectra and without dissipation is constructed well through a coarse grid velocity signal from one experiment's *** filtering the interpolated signal appropriately,the probability distribution of velocity,velocity structure functions and the anomalous scaling law of the synthetic field are close to those of the original signal.

关键词： turbulence stretching interpolation

Wake-Up Security:Effective Security ImprovementMechanism for Low Power Internet of Things

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Intelligent Automation & Soft Computing 2023年第9期37卷 2897-2917页

作者： Sun-Woo Yun Na-Eun Park Il-Gu Lee Department of future convergence technology Engineering Sungshin Women’s UniversitySeoul02844Korea Department of convergence Security Engineering Sungshin Women’s UniversitySeoul02844Korea

As time and space constraints decrease due to the development of wireless communication network technology,the scale and scope of cyber-attacks targeting the Internet of Things(IoT)are ***,it is difficult to apply high-performance security modules to the IoT owing to the limited battery,memory capacity,and data transmission performance depend-ing on the size of the *** research has mainly reduced power consumption by lightening encryption ***,it is difficult to defend large-scale information systems and networks against advanced and intelligent attacks because of the problem of deteriorating security *** this study,we propose wake-up security(WuS),a low-power security architecture that can utilize high-performance security algorithms in an IoT *** introducing a small logic that performs anomaly detection on the IoT platform and executes the security module only when necessary according to the anomaly detection result,WuS improves security and power efficiency while using a relatively high-complexity security module in a low-power environment compared to the conventional method of periodically exe-cuting a high-performance security *** this study,a Python simulator based on the UNSW-NB15 dataset is used to evaluate the power consumption,latency,and security of the proposed *** evaluation results reveal that the power consumption of the proposed WuS mechanism is approxi-mately 51.8%and 27.2%lower than those of conventional high-performance security and lightweight security modules,***,the laten-cies are approximately 74.8%and 65.9%lower,***,the WuS mechanism achieved a high detection accuracy of approximately 96.5%or greater,proving that the detection efficiency performance improved by approximately 33.5%compared to the conventional *** performance evaluation results for the proposed model varied depending on the applied anomaly-detection

关键词： Internet of Things security anomaly detection low-power architecture energy efficiency wake-up security