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A Strategy of Signal Detection for Performance Improvement in Clipping Based OFDM System

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Computers, Materials & Continua 2020年第7期64卷 181-191页

作者： jae-hyun ro Won-Seok Lee Min-Goo Kang Dae-Ki Hong Hyoung-Kyu Song Department of Information and Communication Engineering Sejong UniversitySeoulKorea Department of IT Contents Hanshin UniversityOsan-siKorea Department of System Semiconductor Engineering SangMyung UniversityCheonan-si31066Korea

In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Division Multiplexing(OFDM)*** of the main disadvantages for the OFDM is the high Peak to Average Power Ratio(PAPR).The clipping is a simple method for the PAPR ***,an effect of the clipping is nonlinear distortion,and estimations for transmitting symbols are difficult despite a Maximum Likelihood(ML)detection at the *** DNN based online signal detection uses the offline learning model where all weights and biases at fully-connected layers are set to overcome nonlinear distortions by using training data ***,this paper introduces the required processes for the online signal detection and offline learning,and compares error performances with the ML detection in the clipping-based OFDM *** simulation results,the DNN based signal detection has better error performance than the conventional ML detection in multi-path fading wireless *** performance improvement is large as the complexity of system is increased such as huge Multiple Input Multiple Output(MIMO)system and high clipping rate.

关键词： Clipping DNN ML nonlinear distortion OFDM

Improved MIMO Signal Detection Based on DNN in MIMO-OFDM System

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Computers, Materials & Continua 2022年第2期70卷 3625-3636页

作者： jae-hyun ro Jong-Gyu Ha Woon-Sang Lee Young-Hwan You Hyoung-Kyu Song Department of Convergence Engineering for Intelligent Drone Sejong UniversitySeoul05006Korea Department of Information and Communication Engineering Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea Department of Computer Engineering Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea

This paper proposes the multiple-input multiple-output(MIMO)detection scheme by using the deep neural network(DNN)based ensemble machine learning for higher error performance in wireless communication *** the MIMO detection based on the ensemble machine learning,all learning models for the DNN are generated in offline and the detection is performed in online by using already learned *** the offline learning,the received signals and channel coefficients are set to input data,and the labels which correspond to transmit symbols are set to output *** the online learning,the perfectly learned models are used for signal detection where the models have fixed bias and *** performance improvement,the proposed scheme uses the majority vote and the maximum probability as the methods of the model combinations for obtaining diversity gains at the MIMO *** simulation results show that the proposed scheme has improved symbol error rate(SER)performance without additional receive antennas.

关键词： MIMO DNN ensemble machine learning ML

Weighted Gauss-Seidel Precoder for Downlink Massive MIMO Systems

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Computers, Materials & Continua 2021年第5期67卷 1729-1745页

作者： Jun-Yong Jang Won-Seok Lee jae-hyun ro Young-Hawn You Hyoung-Kyu Song Department of Information and Communication Engineering Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea Department of Computer Engineering Sejong UniversitySeoul05006Korea

In this paper,a novel precoding scheme based on the Gauss-Seidel(GS)method is proposed for downlink massive multiple-input multiple-output(MIMO)*** GS method iteratively approximates the matrix inversion and reduces the overall complexity of the precoding *** addition,the GS method shows a fast convergence rate to the Zero-forcing(ZF)method that requires an exact invertible ***,to satisfy demanded error performance and converge to the error performance of the ZF method in the practical condition such as spatially correlated channels,more iterations are necessary for the GS method and increase the overall *** efficient approximation with fewer iterations,this paper proposes a weighted GS(WGS)method to improve the approximation accuracy of the GS *** optimal weights that accelerate the convergence rate by improved accuracy are computed by the least square(LS)*** the computation of weights,the different weights are applied for each iteration of the GS *** addition,an efficient method of weight computation is proposed to reduce the complexity of the LS *** simulation results show that bit error rate(BER)performance for the proposed scheme with fewer iterations is better than the GS method in spatially correlated channels.

关键词： Massive MIMO GS matrix inversion complexity weight

An Enhanced Jacobi Precoder for Downlink Massive MIMO Systems

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Computers, Materials & Continua 2021年第7期68卷 137-148页

作者： Park Chan-Yeob hyun-ro jae Jun-Yong Jang Song Hyoung-Kyu Department of Information and Communication Engineering and Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea

Linear precoding methods such as zero-forcing(ZF)are near optimal for downlink massive multi-user multiple input multiple output(MIMO)systems due to their asymptotic channel ***,as the number of users increases,the computational complexity of obtaining the inverse matrix of the gram matrix *** the computational complexity problem,this paper proposes an improved Jacobi(JC)-based precoder to improve error performance of the conventional JC in the downlink massive MIMO *** conventional JC was studied for solving the high computational complexity of the ZF algorithm and was able to achieve parallel ***,the conventional JC has poor error performance when the number of users increases,which means that the diagonal dominance component of the gram matrix is *** this paper,the preconditioning method is proposed to improve the error *** executing the JC,the condition number of the linear equation and spectrum radius of the iteration matrix are reduced by multiplying the preconditioning matrix of the linear *** further reduce the condition number of the linear equation,this paper proposes a polynomial expansion precondition matrix that supplements diagonal *** results show that the proposed method provides better performance than other iterative methods and has similar performance to the ZF.

关键词： Jacobi(JC) massive MIMO precondition polynomial expansion linear precoding

Ileal angiomyolipoma manifested by small intestinal intussusception

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World Journal of Gastroenterology 2009年第11期15卷 1398-1400页

作者： Chang Ho Lee Jong Hun Kim Doo hyun Yang Yong Hwang Myoung jae Kang Young Kon Kim Min ro Lee Department of Surgery Chonbuk National University Medical SchoolJeonju 561-180 South Korea Department of Pathology Chonbuk National University Medical SchoolJeonju 561-180 South Korea Department of Radiology Chonbuk National University Medical SchoolJeonju 561-180South Korea

Angiomyolipomas(AMLs),a form of benign mesenchymal hamartoma,arise primarily in the kidneys of patients with or without tuberous ***-renal AMLs are very rare and are most commonly found in the liver. AMLs of the small intestine are exceedingly ***, a case of a 28-year-old man,who presented with ileal intussusception caused by ileal AML is *** clinicopathological and immunohistochemical findings of ileal AMLs are discussed and the literature on small intestinal AMLs is reviewed.

关键词： Angiomyolipoma Intussusception Hamartoma Ileum Colectomy

Risk of sedation for diagnostic esophagogastroduodenoscopy in obstructive sleep apnea patients

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World Journal of Gastroenterology 2013年第29期19卷 4745-4751页

作者： jae Myung Cha Jung Won Jeun Kwan Mi Pack Joung Il Lee Kwang ro Joo hyun Phil Shin Won-Chul Shin Department of Internal Medicine Kyung Hee University Hospital at Gang Dong Seoul 134-727 South Korea Department of Neurology Kyung Hee University Hospital at Gang Dong Seoul 134-727 South Korea

AIM: To investigate whether patients with obstructive sleep apnea (OSA) are at risk of sedation-related complications during diagnostic esophagogastroduodenoscopy (EGD). METHODS: A prospective study was performed in consecutive patients with OSA, who were confirmed with full-night polysomnography between July 2010 and April 2011. The occurrence of cardiopulmonary complications related to sedation during diagnostic EGD was compared between OSA and control groups. RESULTS: During the study period, 31 patients with OSA and 65 controls were enrolled. Compared with the control group, a higher dosage of midazolam was administered (P = 0.000) and a higher proportion of deep sedation was performed (P = 0.024) in the OSA group. However, all adverse events, including sedation fail-ure, paradoxical responses, snoring or apnea, hypoxia, hypotension, oxygen or flumazenil administration, and other adverse events were not different between the two groups (all P > 0.1). Patients with OSA were not predisposed to hypoxia with multivariate logistic regression analysis (P = 0.068). CONCLUSION: In patients with OSA, this limited sized study did not disclose an increased risk of cardiopulmonary complications during diagnostic EGD under sedation.

关键词： Conscious sedation Obstructive sleep apnea Endoscopy Complications Safety

Proton pump inhibitor administration delays rebleeding after endoscopic gastric variceal obturation

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World Journal of Gastroenterology 2014年第45期20卷 17127-17131页

作者： Won Seok Jang hyun Phil Shin Joung Ⅱ Lee Kwang ro Joo jae Myung Cha Jung Won Jeon Jun Uk Lim Department of Internal Medicine College of Medicine Kyung Hee University

AIM: To clarify the efficacy of proton pump inhibitors (PPIs) after endoscopic variceal obturation (EVO) with N-butyl-2-cyanoacrylate.

关键词： Cirrhosis Endoscopic variceal obturation N-butyl-2-cyanoacrylate Proton pump inhibitor Rebleeding interval

SVC bitstream adaptation in MPEG-21 multimedia framework

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 764-772页

作者： THANG Truong Cong KIM Young Suk ro Yong Man KANG Jungwon KIM jae-Gon Department of Engineering Information and Communications UniversityDaejeon 305-732 Korea Department of Engineering Information and Communications University Daejeon 305-732 Korea Electronics and Telecommunications Research Institute Daejeon 305-732 Korea

Scalable video coding (SVC) is the most promising video format for applications of collaborative communication. MPEG-21 standard has newly emerged to enable the interoperability of multimedia delivery in heterogeneous environments. In this paper we study adaptation of SVC bitstream in the context of MPEG-21 multimedia framework. For interfacing SVC bit- stream with MPEG-21 based adaptation system, we propose three SVC specific adaptation operators. Based on our previous work with multidimensional video adaptation, we present an effective approach, using MPEG-21 DIA AdaptationQoS description tool, to model QoS control for SVC adaptation. Then we show how the operator values could be computed from that representation. For the actual adaptation at bitstream level, we propose a procedure to remove the unnecessary NAL units from an SVC bitstream. The result of this study enables QoS management of SVC streaming in an efficient and standardized manner.

关键词： Multidimensional video adaptation, Scalable video coding (SVC), MPEG-21 DIA (Digital Item Adaptation), QoS

Colo-colonic intussusception with post-polypectomy electrocoagulation syndrome:A case report

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World Journal of Clinical Cases 2022年第25期10卷 8939-8944页

作者： jae Young Moon Min-ro Lee Sung Kyun Yim Gi Won Ha Department of Surgery Jeonbuk National University HospitalJeonju 561-180JeonbukSouth Korea Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital Jeonju 561-180JeonbukSouth Korea Department of Internal Medicine Biomedical Research InstituteJeonbuk National University Hospital and Medical SchoolJeonju 54907JeonbukSouth Korea

BACKGroUND Post-polypectomy electrocoagulation syndrome(PPES)can occur after colonoscopic polypectomy and is usually treated conservatively with a positive ***,there can be cases with complications *** SUMMARY A 58-year-old woman,who had no previous medical history,visited the Emergency Department of another hospital with symptoms of abdominal pain and fever,1 d after multiple colonoscopic *** abdominopelvic computed tomography(CT)scan demonstrated colo-colonic intussusception,and she was transferred to our hospital to consider an *** showed colocolonic intussusception with PPES and no evidence of *** physical examination showed localized mild tenderness on the right sided *** patient fasted and was admitted for treatment with intravenous antibiotics(piperacillin/tazobactam 4.5 g each 8 h,ornidazole 500 mg each 12 h).After admission,the symptoms got better and a follow-up CT scan demonstrated resolution of the PPES and *** patient was discharged on hospital day *** Colo-colic intussusception can occur with PPES,and it can be properly treated conservatively.

关键词： Intussusception Endoscopy Colonoscopy Colonic polyps Intestinal polyps Case report