Grid-based Correlation Localization Method in Mixed Line-of-Sight/Non-Line-of-Sight Environments

( Riming Wang ),( Jiuchao Feng ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.1

Considering the localization estimation issue in mixed line-of-sight (LOS)/non-LOS(NLOS) environments based on received signal strength (RSS) measurements in wireless sensor networks, a grid-based correlation method based on the relationship between distance and RSS is proposed in this paper. The Maximum-Likelihood (ML) estimator is appended to further improve the localization accuracy. Furthermore, in order to reduce computation load and enhance performance, an improved recursively version with NLOS mitigation is also proposed. The most advantages of the proposed localization algorithm is that, it does not need any prior knowledge of the propagation model parameters and therefore does not need any offline calibration effort to calibrate the model parameters in harsh environments, which makes it more convenient for rapid implementation in practical applications. The simulation and experimental results evidence that the proposed localization algorithm exhibits good localization performance and flexibilities for different devices.

Lossless Image Compression Using Differential Pulse Code Modulation and Its Application

Rime Raj Singh Tomar,Kapil Jain 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

Images include information about human body which is used for different purpose such as medical examination security and other plans Compression of images is used in some applications such as profiling information and transmission systems. Regard to importance of images information, lossless or loss compression is preferred. Lossless compressions are JPEG, JPEG-LS and JPEG2000 are few well-known methods for lossless compression. We will use differential pulse code modulation for image compression with Huffman encoder, which is one of the latest and provides good compression ratio, peak signal to noise ratio and minimum mean square error. In real time application which needs hardware implementation, low complex algorithm accelerate compression process. In this paper, we use differential pulse code modulation for image compression lossless and near-lossless compression method is introduced which is efficient due to its high compression ratio and simplicity. This method is consists of a new transformation method called Enhanced DPCM Transformation (EDT) which has a good energy compaction and a suitable Huffman encoding. After introducing this compression method it is applied on different images from Corel dataset for experimental results and analysis. Also we compare it with other existing methods with respect to parameter compression ratio, peak signal noise ratio and mean square error.

Lossless Image Compression using Differential Pulse Code Modulation and Its purpose

Rime Raj Singh Tomar,Kapil Jain 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

Images include information about human body which is used for different purposes such as medical, security and other plans. Compression of images is used in some applications such as profiling data and transmission systems. Regard to importance of images information, lossless or lossy compression is preferred. Lossless compressions are JPEG, JPEG-LS and JPEG 2000 is few well-known methods for lossless compression. We will use differential pulse code modulation for image compression with Huffman encoder, which is one of the latest and provides good compression ratio, peak signal noise ratio and minimum mean square error. In real time application which needs hardware implementation, low complex algorithm accelerates compression process. In this dissertation, we use differential pulse code modulation for image compression lossless and near-lossless compression method is introduced which is efficient due to its high compression ratio and simplicity. This method is consists of a new transformation method called Enhanced DPCM Transformation (EDT) which has a good energy compaction and a suitable Huffman encoding. After introduce this compression method, it is apply on different images from Corel dataset for experimental results and analysis. As well we compare it with other existing methods with respect to parameter compression ratio, peak signal noise ratio and mean square error.

Advanced Building Blocks of Power Converters for Renewable Energy Based Distributed Generators

Riming Shao,Mary Kaye,Liuchen Chang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The power converter is a critical component of a distributed generation (DG) system, particularly for a renewable energy based distributed generator. With the rapid development and growing applications of DG systems, power converters have evolved from a traditional “power conversion device” to a “system integrator”. This paper outlines the basic and advanced building blocks of power converters for distributed generation systems, with an emphasis on the new algorithms developed especially for grid-connected single-phase power converters in small wind turbines and photovoltaic systems. A grid-connected power converter should feed power of a high quality into a grid with a low total harmonic distortion (THD), and fast dynamic response to the variations of a renewable energy resource. The newly developed space vector based pulse-width-modulation (PWM) with predictive current control provides a direct cycle-by-cycle regulation of the current waveform feeding into the grid. Effective anti-islanding is an essential function of a power converter, in compliance with the grid interconnection requirements. As active islanding detection methods exert disturbances to the grid and passive islanding detection methods generally have large non-detection zones, new and hybrid islanding detection methods have been developed. A power spectral density method has been developed to continuously monitor and identify the possible features of an islanding formation. Maximum power extraction from renewable energy resources is vitally important for distributed generators. Many algorithms have been developed for maximum power point tracking (MPPT) of photovoltaic and wind energy systems. A new MPPT method has been developed by integrating the fast extremum-finding method of Golden Section Search (GSS) into a multi-stage MPPT algorithm. The proposed MPPT algorithm provides fast response (in the order of 40 msec) and high tracking accuracy (99.9%) as compared to the existing algorithms.

Characterization of Energy Conversion of Synechococcus sp. PCC7942 under Photoautotrophic Conditions Based on Metabolic Flux and Chlorophyll Fluorescence Analysis

Riming Yan,Zhibin Zhang,Qinggui Zeng,Du Zhu,Ju Chu 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3

Energy conversion efficiency of photoautotrophic microalgae plays an important role in the utilization of light energy for cell growth and production of metabolites. To understand the utilization of light energy,Synechococcus sp. PCC7942 was cultivated at different incident light intensities of 15.8, 47.3, and 94.6 μmol/m^2/sec in continuous culture. The influence of light on the carbon and energy metabolism of microalgae was investigated by combining metabolic flux analysis (MFA) and chlorophyll fluorescence analysis (CFA). Results showed that the yields of biomass based on ATP (Y_(ATP)) and total light energy (Y_E) both declined with increasing light, and the maximal values of Y_(ATP) and Y_E were estimated to be 4.73 g/mol-ATP, and 17.10 × 10_(−3) g/kJ respectively, at the examined conditions. The overall efficiency of energy conversion against total absorbed energy changed with the varying irradiances. However, the actual conversion efficiency of total energy based on CFA was almost constant,regardless of the different irradiances used in the present study.

Efficient Solar Cells Based on Light-Harvesting Antimony Sulfoiodide

Nie, Riming,Yun, Hyun-sung,Paik, Min-Jae,Mehta, Aarti,Park, Byung-wook,Choi, Yong Chan,Seok, Sang Il Wiley-VCH 2018 ADVANCED ENERGY MATERIALS Vol.8 No.7

<P> Although antimony sulfoiodide (SbSI) exhibits very interesting properties including high photoconductivity, ferroelectricity, and piezoelectricity, it is not applied to solar cells. Meanwhile, SbSI is predominantly prepared as a powder using a high-temperature, high-pressure system. Herein, the fabrication of solar cells utilizing SbSI as light harvesters is reported for the first time to the best of knowledge. SbSI is prepared by solution processing, followed by annealing under mild temperature conditions by a reaction between antimony trisulfide, which is deposited by chemical bath deposition on a mesoporous TiO<SUB>2</SUB> electrode and antimony triiodide, under air at a low temperature (90 °C) without any external pressure. The solar cells fabricated using SbSI exhibit a power conversion efficiency of 3.05% under standard illumination conditions of 100 mW cm<SUP>-2</SUP>. </P>

Mixed Sulfur and Iodide-Based Lead-Free Perovskite Solar Cells

Nie, Riming,Mehta, Aarti,Park, Byung-wook,Kwon, Hyoung-Woo,Im, Jino,Seok, Sang Il American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.3

<P>The use of divalent chalcogenides and monovalent halides as anions in a perovskite structure allows the introduction of 3<SUP>+</SUP> and 4<SUP>+</SUP> charged cations in the place of the 2<SUP>+</SUP> metal cations. Herein we report for the first time on the fabrication of solar cells exploiting methylammonium antimony sulfur diiodide (MASbSI<SUB>2</SUB>) perovskite structures, as light harvesters. The MASbSI<SUB>2</SUB> was prepared by annealing under mild temperature conditions, via a sequential reaction between antimony trisulfide (Sb<SUB>2</SUB>S<SUB>3</SUB>), which is deposited by the chemical bath deposition (CBD) method, antimony triiodide (SbI<SUB>3</SUB>), and methylammonium iodide (MAI) onto a mesoporous TiO<SUB>2</SUB> electrode, and then annealed at 150 °C in an argon atmosphere. The solar cells fabricated using MASbSI<SUB>2</SUB> exhibited power conversion efficiencies (PCE) of 3.08%, under the standard illumination conditions of 100 mW/cm<SUP>2</SUP>.</P> [FIG OMISSION]</BR>

Control Strategy for an Electromechanical Transmission Vehicle Based on a Double Markov Process

Liu Hui,Xu Riming,Han Lijin,Xiong Shanshan 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.3

Based on an analysis of the driving demand and system dynamics of heavy-duty vehicles equipped with electromechanical transmission (EMT), a double Markov model is put forward to represent drivers’ power demand for driving and electricity. Transfer probability matrices are calculated by utilizing the maximum likelihood estimation method. A power distribution control strategy based on stochastic dynamic programming (SDP) is proposed. With economy being the optimization goal, the model for power allocation control based on SDP is established while regarding the engine torque, motor speeds, vehicle speed and state of charge (SOC) as state variables’ engine speed and motor torques as control variables’ and power demands as interference variables. The SDP problem is solved by an improved policy iteration algorithm based on value iteration and policy iteration algorithms.

Predictive current controller and compensator‑based discrete current controller for single‑phase bridge inverters

Jinghua Zhou,Shuang Xu,Riming Shao,Liuchen Chang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.9

Transfer efficiency and power quality are two critical factors when it comes to grid-connected distributed generation systems. Single-phase inverters are commonly used in distributed generation systems under 10 kilowatts as the connection between the gird and renewable energy sources (RESs). In this application, grid current distortion plays a pivotal role in determining inverter performance. In this article, an improved current control strategy based on a predictive current controller (PCC) and a compensator is presented to decrease current harmonic distortion and increase power quality. The controller design method inspects a single-phase inverter system as a digital platform, and designs the controller in discrete time in order to obtain a more precise and effective controller than that in continuous time. The discretization procedures using sampling and hold (S&H) are taken into consideration in the design process. The improved current controller is a DSP-based digital current controller for grid-connected single-phase bridge inverters, whose performance is optimized by considering the time delay caused by analog–digital conversion (ADC) and computations. A comparison has been made to analyze the performance of the single-phase grid-connected inverter system with PCC and ICC. Experimental results are shown to validate the effectiveness of the designed current controller.

Long-Term (Postnatal Day 70) Outcome and Safety of Intratracheal Transplantation of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Neonatal Hyperoxic Lung Injury

안소윤,장윤실,김수윤,성동경,김은선,So Yub Rime,유욱준,최수진,오원일,박원순 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.2

Purpose: This study was performed to evaluate the long-term effects and safety of intratracheal (IT) transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in neonatal hyperoxic lung injury at postnatal day (P)70 in a rat model. Materials and Methods: Newborn Sprague Dawley rat pups were subjected to 14 days of hyperoxia (90% oxygen) within 10 hours after birth and allowed to recover at room air until sacrificed at P70. In the transplantation groups, hUCB-MSCs (5×105) were administered intratracheally at P5. At P70, various organs including the heart, lung, liver, and spleen were histologically examined, and the harvested lungs were assessed for morphometric analyses of alveolarization. ED-1, von Willebrand factor, and human-specific nuclear mitotic apparatus protein (NuMA) staining in the lungs and the hematologic profile of blood were evaluated. Results: Impaired alveolar and vascular growth, which evidenced by an increased mean linear intercept and decreased amount of von Willebrand factor, respectively, and the hyperoxia-induced inflammatory responses, as evidenced by inflammatory foci and ED-1 positive alveolar macrophages, were attenuated in the P70 rat lungs by IT transplantation of hUCB-MSCs. Although rare, donor cells with human specific NuMA staining were persistently present in the P70 rat lungs. There were no gross or microscopic abnormal findings in the heart, liver, or spleen, related to the MSCs transplantation. Conclusion: The protective and beneficial effects of IT transplantation of hUCB-MSCs in neonatal hyperoxic lung injuries were sustained for a prolonged recovery period without any long-term adverse effects up to P70.