Search results for: Song W. Park
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 574

Search results for: Song W. Park

424 H∞ Approach to Functional Projective Synchronization for Chaotic Systems with Disturbances

Authors: S. M. Lee, J. H. Park, H. Y. Jung

Abstract:

This paper presents a method for functional projective H∞ synchronization problem of chaotic systems with external disturbance. Based on Lyapunov theory and linear matrix inequality (LMI) formulation, the novel feedback controller is established to not only guarantee stable synchronization of both drive and response systems but also reduce the effect of external disturbance to an H∞ norm constraint.

Keywords: Chaotic systems, functional projective H∞ synchronization, LMI.

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423 An Improved Lattice Reduction Aided Detection Scheme for MIMO-OFDM System

Authors: Jang-Kyun Ahn, Seung-Jun Yu, Eui-Young Lee, Hyoung-Kyu Song

Abstract:

This paper proposes an efficient lattice-reduction-aided detection (LRD) scheme to improve the detection performance of MIMO-OFDM system. In this proposed scheme, V candidate symbols are considered at the first layer, and V probable streams are detected with LRD scheme according to the first detected V candidate symbols. Then, the most probable stream is selected through a ML test. Since the proposed scheme can more accurately detect initial symbol and can reduce transmission of error to rest symbols, the proposed scheme shows more improved performance than conventional LRD with very low complexity.

Keywords: Lattice reduction aided detection, MIMO-OFDM, QRD-M, V-BLAST.

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422 Single and Multiple Sourcing in the Auto-Manufacturing Industry

Authors: Sung Ho Ha, Eun Kyoung Kwon, Jong Sik Jin, Hyun Sun Park

Abstract:

This article outlines a hybrid method, incorporating multiple techniques into an evaluation process, in order to select competitive suppliers in a supply chain. It enables a purchaser to do single sourcing and multiple sourcing by calculating a combined supplier score, which accounts for both qualitative and quantitative factors that have impact on supply chain performance.

Keywords: Analytic hierarchy process, Data envelopment analysis, Neural network, Supply chain management.

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421 A Pairing-based Blind Signature Scheme with Message Recovery

Authors: Song Han, Elizabeth Chang

Abstract:

Blind signatures enable users to obtain valid signatures for a message without revealing its content to the signer. This paper presents a new blind signature scheme, i.e. identity-based blind signature scheme with message recovery. Due to the message recovery property, the new scheme requires less bandwidth than the identitybased blind signatures with similar constructions. The scheme is based on modified Weil/Tate pairings over elliptic curves, and thus requires smaller key sizes for the same level of security compared to previous approaches not utilizing bilinear pairings. Security and efficiency analysis for the scheme is provided in this paper.

Keywords: Blind Signature, Message Recovery, Pairings, Elliptic Curves, Blindness

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420 Investigating the Determinants of Purchase Intention in C2C E-Commerce

Authors: Kee-Young Kwahk, Xi Ge, Jun-Hyung Park

Abstract:

This study aims to examine the determinants of purchase intention in C2C e-commerce. Specifically the role of instant messaging in the C2C e-commerce contextis investigated. In addition to instant messaging, we brought in two antecedents of purchase intention - trust and customer satisfaction - to establish a theoretical research model. Structural equation modeling using LISREL was used to analyze the data.We discussed the research findings and suggested some implications for researchers and practitioners.

Keywords: E-commerce, Online marketing, C2C, Purchase Intention

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419 Cooperative CDD Scheme Based on Hierarchical Modulation in OFDM System

Authors: Seung-Jun Yu, Yeong-Seop Ahn, Young-Min Ko, Hyoung-Kyu Song

Abstract:

In order to achieve high data rate and increase the spectral efficiency, multiple input multiple output (MIMO) system has been proposed. However, multiple antennas are limited by size and cost. Therefore, recently developed cooperative diversity scheme, which profits the transmit diversity only with the existing hardware by constituting a virtual antenna array, can be a solution. However, most of the introduced cooperative techniques have a common fault of decreased transmission rate because the destination should receive the decodable compositions of symbols from the source and the relay. In this paper, we propose a cooperative cyclic delay diversity (CDD) scheme that use hierarchical modulation. This scheme is free from the rate loss and allows seamless cooperative communication.

Keywords: MIMO, Cooperative communication, CDD, Hierarchical modulation.

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418 The Dividend Payments for General Claim Size Distributions under Interest Rate

Authors: Li-Li Li, Jinghai Feng, Lixin Song

Abstract:

This paper evaluates the dividend payments for general claim size distributions in the presence of a dividend barrier. The surplus of a company is modeled using the classical risk process perturbed by diffusion, and in addition, it is assumed to accrue interest at a constant rate. After presenting the integro-differential equation with initial conditions that dividend payments satisfies, the paper derives a useful expression of the dividend payments by employing the theory of Volterra equation. Furthermore, the optimal value of dividend barrier is found. Finally, numerical examples illustrate the optimality of optimal dividend barrier and the effects of parameters on dividend payments.

Keywords: Dividend payout, Integro-differential equation, Jumpdiffusion model, Volterra equation

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417 A Fuzzy Classifier with Evolutionary Design of Ellipsoidal Decision Regions

Authors: Leehter Yao, Kuei-Song Weng, Cherng-Dir Huang

Abstract:

A fuzzy classifier using multiple ellipsoids approximating decision regions for classification is to be designed in this paper. An algorithm called Gustafson-Kessel algorithm (GKA) with an adaptive distance norm based on covariance matrices of prototype data points is adopted to learn the ellipsoids. GKA is able toadapt the distance norm to the underlying distribution of the prototypedata points except that the sizes of ellipsoids need to be determined a priori. To overcome GKA's inability to determine appropriate size ofellipsoid, the genetic algorithm (GA) is applied to learn the size ofellipsoid. With GA combined with GKA, it will be shown in this paper that the proposed method outperforms the benchmark algorithms as well as algorithms in the field.

Keywords: Ellipsoids, genetic algorithm, classification, fuzzyc-means (FCM)

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416 Synchronization Between Two Chaotic Systems: Numerical and Circuit Simulation

Authors: J. H. Park, T. H. Lee, S. M. Lee, H. Y. Jung

Abstract:

In this paper, a generalized synchronization scheme, which is called function synchronization, for chaotic systems is studied. Based on Lyapunov method and active control method, we design the synchronization controller for the system such that the error dynamics between master and slave chaotic systems is asymptotically stable. For verification of our theory, computer and circuit simulations for a specific chaotic system is conducted.

Keywords: Chaotic systems, synchronization, Lyapunov method, simulation.

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415 Research on the Micro Pattern forming of Spiral Grooves in a Dynamic Thrust Bearing

Authors: Sol-Kil Oh, Hye-Jin Lee, Jung-Han Song, Kyoung-Tae Kim, Nak-Kyu Lee, Jong-Ho Kim

Abstract:

This paper deals with a novel technique for the fabrication of Spiral grooves in a dynamic thrust bearing. The main scheme proposed in this paper is to fabricate the microgrooves using desktop forming system. This process has advantages compared to the conventional electro-chemical machining in the viewpoint of a higher productivity. For this reason, a new testing apparatus is designed and built for press forming microgrooves on a surface of the thrust bearing. The material used in this study is sintered Cu-Fe alloy. The effects of the forming load on the performance of micro press forming are experimentally investigated. From the experimental results, formed depths are closed to the target ones with increasing the forming load.

Keywords: Desktop forming system, Fluid dynamic bearing, Thrust bearing, Microgroove.

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414 MAP-Based Image Super-resolution Reconstruction

Authors: Xueting Liu, Daojin Song, Chuandai Dong, Hongkui Li

Abstract:

From a set of shifted, blurred, and decimated image , super-resolution image reconstruction can get a high-resolution image. So it has become an active research branch in the field of image restoration. In general, super-resolution image restoration is an ill-posed problem. Prior knowledge about the image can be combined to make the problem well-posed, which contributes to some regularization methods. In the regularization methods at present, however, regularization parameter was selected by experience in some cases and other techniques have too heavy computation cost for computing the parameter. In this paper, we construct a new super-resolution algorithm by transforming the solving of the System stem Є=An into the solving of the equations X+A*X-1A=I , and propose an inverse iterative method.

Keywords: High-resolution MAP image, Reconstruction, Image interpolation, Motion Estimation, Hermitian positive definite solutions.

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413 An Improved Cooperative Communication Scheme for IoT System

Authors: Eui-Hak Lee, Jae-Hyun Ro, Hyoung-Kyu Song

Abstract:

In internet of things (IoT) system, the communication scheme with reliability and low power is required to connect a terminal. Cooperative communication can achieve reliability and lower power than multiple-input multiple-output (MIMO) system. Cooperative communication increases the reliability with low power, but decreases a throughput. It has a weak point that the communication throughput is decreased. In this paper, a novel scheme is proposed to increase the communication throughput. The novel scheme is a transmission structure that increases transmission rate. A decoding scheme according to the novel transmission structure is proposed. Simulation results show that the proposed scheme increases the throughput without bit error rate (BER) performance degradation.

Keywords: Cooperative communication, IoT, STBC, Transmission rate.

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412 Design and Implementation of Cricket-based Location Tracking System

Authors: Byung Ki Kim, Ho Min Jung, Jae-Bong Yoo, Wan Yeon Lee, Chan Young Park, Young Woong Ko

Abstract:

In this paper, we present a novel approach to location system under indoor environment. The key idea of our work is accurate distance estimation with cricket-based location system using A* algorithm. We also use magnetic sensor for detecting obstacles in indoor environment. Finally, we suggest how this system can be used in various applications such as asset tracking and monitoring.

Keywords: Cricket, Indoor Location Tracking, Mobile Robot, Localization.

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411 Production of As Isotopes in the Interaction of natGe with 14-30 MeV Protons

Authors: Yong H. Chung, Eun J. Han, Seil Lee, Sun Y. Park, Eun H. Yoon, Eun J. Cho, Jang H. Lee, Young J. Chu, Jang H. Ha, Jongseo Chai, Yu S. Kim, Min Y. Lee, Hyeyoung Lee

Abstract:

Cross sections of As radionuclides in the interaction of natGe with 14-30 MeV protons have been deduced by off-line y-ray spectroscopy to find optimal reaction channels leading to radiotracers for positron emission tomography. The experimental results were compared with the previous results and those estimated by the compound nucleus reaction model.

Keywords: Compound nucleus reaction model, off-line g-ray spectroscopy, radionuclide.

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410 Design of Orientation-Free Handler and Fuzzy Controller for Wire-Driven Heavy Object Lifting System

Authors: Bo-Wei Song, Yun-Jung Lee

Abstract:

This paper presents an intention interface and controller for a wire-driven heavy object lifting system that assists the operator with moving a heavy object. The handler is designed to allow a comfortable working posture for the operator. Plus, as a human assistive system, the operator is involved in the control loop, where a fuzzy control system is used to consider the human control characteristics. The effectiveness and performance of the proposed system are proved by experiments.

Keywords: Fuzzy controller, Handler design, Heavy object lifting system, Human-assistive device, Human-in-the-loop system.

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409 A New Proxy Signature Scheme As Secure As ElGamal Signature

Authors: Song Han, Elizabeth Chang, Jie Wang, Wanquan Liu

Abstract:

Proxy signature helps the proxy signer to sign messages on behalf of the original signer. It is very useful when the original signer (e.g. the president of a company) is not available to sign a specific document. If the original signer can not forge valid proxy signatures through impersonating the proxy signer, it will be robust in a virtual environment; thus the original signer can not shift any illegal action initiated by herself to the proxy signer. In this paper, we propose a new proxy signature scheme. The new scheme can prevent the original signer from impersonating the proxy signer to sign messages. The proposed scheme is based on the regular ElGamal signature. In addition, the fair privacy of the proxy signer is maintained. That means, the privacy of the proxy signer is preserved; and the privacy can be revealed when it is necessary.

Keywords: ElGamal signature, Proxy signature, Security, Hash function, Fair privacy.

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408 Accelerating Sparse Matrix Vector Multiplication on Many-Core GPUs

Authors: Weizhi Xu, Zhiyong Liu, Dongrui Fan, Shuai Jiao, Xiaochun Ye, Fenglong Song, Chenggang Yan

Abstract:

Many-core GPUs provide high computing ability and substantial bandwidth; however, optimizing irregular applications like SpMV on GPUs becomes a difficult but meaningful task. In this paper, we propose a novel method to improve the performance of SpMV on GPUs. A new storage format called HYB-R is proposed to exploit GPU architecture more efficiently. The COO portion of the matrix is partitioned recursively into a ELL portion and a COO portion in the process of creating HYB-R format to ensure that there are as many non-zeros as possible in ELL format. The method of partitioning the matrix is an important problem for HYB-R kernel, so we also try to tune the parameters to partition the matrix for higher performance. Experimental results show that our method can get better performance than the fastest kernel (HYB) in NVIDIA-s SpMV library with as high as 17% speedup.

Keywords: GPU, HYB-R, Many-core, Performance Tuning, SpMV

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407 Normalized Cumulative Spectral Distribution in Music

Authors: Young-Hwan Song, Hyung-Jun Kwon, Myung-Jin Bae

Abstract:

As the remedy used music becomes active and meditation effect through the music is verified, people take a growing interest about psychological balance or remedy given by music. From traditional studies, it is verified that the music of which spectral envelop varies approximately as 1/f (f is frequency) down to a frequency of low frequency bandwidth gives psychological balance. In this paper, we researched signal properties of music which gives psychological balance. In order to find this, we derived the property from voice. Music composed by voice shows large value in NCSD. We confirmed the degree of deference between music by curvature of normalized cumulative spectral distribution. In the music that gives psychological balance, the curvature shows high value, otherwise, the curvature shows low value.

Keywords: Cognitive Psychology, Normalized Cumulative Spectral Distribution, Curvature.

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406 Dispenser Longitudinal Movement ControlDesign Based on Auto - Disturbances –Rejection - Controller

Authors: Qiaozhen Song

Abstract:

Based on the feature of model disturbances and uncertainty being compensated dynamically in auto – disturbances-rejection-controller (ADRC), a new method using ADRC is proposed for the decoupling control of dispenser longitudinal movement in big flight envelope. Developed from nonlinear model directly, ADRC is especially suitable for dynamic model that has big disturbances. Furthermore, without changing the structure and parameters of the controller in big flight envelope, this scheme can simplify the design of flight control system. The simulation results in big flight envelope show that the system achieves high dynamic performance, steady state performance and the controller has strong robustness.

Keywords: ADRC, ESO, nonlinear system

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405 Freedom of Media, Democracy and Gezi Park

Authors: Emine Tirali

Abstract:

This article provides a conceptual framework of the freedom of media and its correlation with democracy. In a democracy, media should serve the publics’ right to know and reflect human rights violations and offer options for meaningful political choices and effective participation in civic affairs. On that point, the 2013 events at Gezi Park in Turkey are a good empirical example to be discussed. During the events, when self-censorship was broadly employed by mainstream Turkish media, social media filled the important role of providing information to the public. New technologies have made information into a fundamental tool for change and growth, and as a consequence, societies worldwide have merged into a single, interdependent, and autonomous organism. For this reason, violations of human rights can no longer be considered domestic issues, but rather global ones. Only global political action is an adequate response. Democracy depends on people shaping the society they live in, and in order to accomplish this, they need to express themselves. Freedom of expression is therefore necessary in order to understand diversity and differing perspectives, which in turn are necessary to resolve conflicts among people. Moreover, freedom of information is integral to freedom of expression. In this context, the international rules and laws regarding freedom of expression and freedom of information – indispensable for a free and independent media – are examined. These were put in place by international institutions such as the United Nations, UNESCO, the Council of Europe, and the European Union, which have aimed to build a free, democratic, and pluralist world committed to human rights and the rule of law. The methods of international human rights institutions depend on effective and frequent employment of mass media to relay human rights violations to the public. Therefore, in this study, the relationship between mass media and democracy, the process of how mass media forms public opinion, the problems of mass media, the neo-liberal theory of mass media, and the use of mass media by NGOs will be evaluated.

Keywords: Freedom of expression, democracy, public opinion, self-censorship.

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404 Sampled-Data Control for Fuel Cell Systems

Authors: H. Y. Jung, Ju H. Park, S. M. Lee

Abstract:

Sampled-data controller is presented for solid oxide fuel cell systems which is expressed by a sector bounded nonlinear model. The proposed control law is obtained by solving a convex problem satisfying several linear matrix inequalities. Simulation results are given to show the effectiveness of the proposed design method.

Keywords: Sampled-data control, Sector bound, Solid oxide fuel cell, Time-delay.

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403 The Management of Media Literacy Development for Thai Students

Authors: Supranee Wattanasin

Abstract:

The purpose of this research was to enhance student’s media literacy. The process was divided into 4 periods: the first phase was to hold the meeting for 100 representatives from various institutions in Thailand; the second phase allowed them to design activities to be used in their institutions; the third implemented activities to reach other target groups; and the last phase was to summarize results. It was found that the participants had clear understanding on media literacy. They knew well about the media. In other words, they knew the difference between creative media and bad ones. Students could use analytical process when searching for information. Thus, the project enabled the students to use analytical thinking skills in designing new activities. Therefore, they could creatively integrate Thai folk song with short movies and cartoons. To increase students’ media literacy, there should be chances for them to gain first-hand experience.

Keywords: Management, development, media literacy, Thai students.

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402 A Novel Design for Hybrid Space-Time Block Codes and Spatial Multiplexing Scheme

Authors: Seung-Jun Yu, Jang-Kyun Ahn, Eui-Young Lee, Hyoung-Kyu Song

Abstract:

Space-time block codes (STBC) and spatial multiplexing (SM) are promising techniques that effectively exploit multipleinput multiple-output (MIMO) transmission to achieve more reliable communication and a higher multiplexing rate, respectively. In this paper, we study a practical design for hybrid scheme with multi-input multi-output orthogonal frequency division multiplexing (MIMOOFDM) systems to flexibly maximize the tradeoff between diversity and multiplexing gains. Unlike the existing STBC and SM designs which are suitable for the integer multiplexing rate, the proposed design can achieve arbitrary number of multiplexing rate.

Keywords: Space-Time Block Codes, Spatial Multiplexing, MIMO-OFDM.

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401 On SNR Estimation by the Likelihood of near Pitch for Speech Detection

Authors: Young-Hwan Song, Doo-Heon Kyun, Jong-Kuk Kim, Myung-Jin Bae

Abstract:

People have the habitual pitch level which is used when people say something generally. However this pitch should be changed irregularly in the presence of noise. So it is useful to estimate SNR of speech signal by pitch. In this paper, we obtain the energy of input speech signal and then we detect a stationary region on voiced speech. And we get the pitch period by NAMDF for the stationary region that is not varied pitch rapidly. After getting pitch, each frame is divided by pitch period and the likelihood of closed pitch is estimated. In this paper, we proposed new parameter, NLF, to estimate the SNR of received speech signal. The NLF is derived from the correlation of near pitch periods. The NLF is obtained for each stationary region in voiced speech. Finally we confirmed good performance of the estimation of the SNR of received input speech in the presence of noise.

Keywords: Likelihood, pitch, SNR, speech.

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400 Comparison of Back-Projection with Non-Uniform Fast Fourier Transform for Real-Time Photoacoustic Tomography

Authors: Moung Young Lee, Chul Gyu Song

Abstract:

Photoacoustic imaging is the imaging technology that combines the optical imaging and ultrasound. This provides the high contrast and resolution due to optical imaging and ultrasound imaging, respectively. We developed the real-time photoacoustic tomography (PAT) system using linear-ultrasound transducer and digital acquisition (DAQ) board. There are two types of algorithm for reconstructing the photoacoustic signal. One is back-projection algorithm, the other is FFT algorithm. Especially, we used the non-uniform FFT algorithm. To evaluate the performance of our system and algorithms, we monitored two wires that stands at interval of 2.89 mm and 0.87 mm. Then, we compared the images reconstructed by algorithms. Finally, we monitored the two hairs crossed and compared between these algorithms.

Keywords: Back-projection, image comparison, non-uniform FFT, photoacoustic tomography.

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399 Development of the Measurement Apparatus for the Effective Thermal Conductivity of Core Material

Authors: Jongmin Kim, Tae-Ho Song

Abstract:

A measurement apparatus is designed and fabricated to measure the effective thermal conductivity (keff) of a VIP (vacuum insulation panel) core specimen under various vacuum states and external loads. The apparatus consists of part for measuring keff, and parts for controlling external load and vacuum condition. Uncertainty of the apparatus is validated by measuring the standard reference material and comparing with commercial devices with VIP samples. Assessed uncertainty is maximum 2.5 % in case of the standard reference material, 10 % in case of VIP samples. Using the apparatus, keff of glass paper under various vacuum levels is examined.

Keywords: Effective thermal conductivity, guarded hot plate method, vacuum insulation panel

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398 A Novel Tracking Method Using Filtering and Geometry

Authors: Sang Hoon Lee, Jong Sue Bae, Taewan Kim, Jin Mo Song, Jong Ju Kim

Abstract:

Image target detection and tracking methods based on target information such as intensity, shape model, histogram and target dynamics have been proven to be robust to target model variations and background clutters as shown by recent researches. However, no definitive answer has been given to occluded target by counter measure or limited field of view(FOV). In this paper, we will present a novel tracking method using filtering and computational geometry. This paper has two central goals: 1) to deal with vulnerable target measurements; and 2) to maintain target tracking out of FOV using non-target-originated information. The experimental results, obtained with airborne images, show a robust tracking ability with respect to the existing approaches. In exploring the questions of target tracking, this paper will be limited to consideration of airborne image.

Keywords: Tracking, Computational geometry, Homography, Filter

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397 Efficient Signal Detection Using QRD-M Based On Channel Condition in MIMO-OFDM System

Authors: Jae-Jeong Kim, Ki-Ro Kim, Hyoung-Kyu Song

Abstract:

In this paper, we propose an efficient signal detector that switches M parameter of QRD-M detection scheme is proposed for MIMO-OFDM system. The proposed detection scheme calculates the threshold by 1-norm condition number and then switches M parameter of QRD-M detection scheme according to channel information. If channel condition is bad, the parameter M is set to high value to increase the accuracy of detection. If channel condition is good, the parameter M is set to low value to reduce complexity of detection. Therefore, the proposed detection scheme has better tradeoff between BER performance and complexity than the conventional detection scheme. The simulation result shows that the complexity of proposed detection scheme is lower than QRD-M detection scheme with similar BER performance.

Keywords: MIMO-OFDM, QRD-M, Channel condition.

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396 Implementation of an IoT Sensor Data Collection and Analysis Library

Authors: Jihyun Song, Kyeongjoo Kim, Minsoo Lee

Abstract:

Due to the development of information technology and wireless Internet technology, various data are being generated in various fields. These data are advantageous in that they provide real-time information to the users themselves. However, when the data are accumulated and analyzed, more various information can be extracted. In addition, development and dissemination of boards such as Arduino and Raspberry Pie have made it possible to easily test various sensors, and it is possible to collect sensor data directly by using database application tools such as MySQL. These directly collected data can be used for various research and can be useful as data for data mining. However, there are many difficulties in using the board to collect data, and there are many difficulties in using it when the user is not a computer programmer, or when using it for the first time. Even if data are collected, lack of expert knowledge or experience may cause difficulties in data analysis and visualization. In this paper, we aim to construct a library for sensor data collection and analysis to overcome these problems.

Keywords: Clustering, data mining, DBSCAN, k-means, k-medoids, sensor data.

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395 Fitness Action Recognition Based on MediaPipe

Authors: Zixuan Xu, Yichun Lou, Yang Song, Zihuai Lin

Abstract:

MediaPipe is an open-source machine learning computer vision framework that can be ported into a multi-platform environment, which makes it easier to use it to recognize human activity. Based on this framework, many human recognition systems have been created, but the fundamental issue is the recognition of human behavior and posture. In this paper, two methods are proposed to recognize human gestures based on MediaPipe, the first one uses the Adaptive Boosting algorithm to recognize a series of fitness gestures, and the second one uses the Fast Dynamic Time Warping algorithm to recognize 413 continuous fitness actions. These two methods are also applicable to any human posture movement recognition.

Keywords: Computer Vision, MediaPipe, Adaptive Boosting, Fast Dynamic Time Warping.

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