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An improved low-complexity sum-product decoding algorithm for low-density parity-check codes

Michaelraj Kingston ROBERTS,Ramesh JAYABALAN

《信息与电子工程前沿（英文）》 2015年 第16卷 第6期   页码 511-518 doi: 10.1631/FITEE.1400269

摘要： In this paper, an improved low-complexity sum-product decoding algorithm is presented for low-density parity-check (LDPC) codes. In the proposed algorithm, reduction in computational complexity is achieved by utilizing fast Fourier transform (FFT) with time shift in the check node process. The improvement in the decoding performance is achieved by utilizing an optimized integer constant in the variable node process. Simulation results show that the proposed algorithm achieves an overall coding gain improvement ranging from 0.04 to 0.46 dB. Moreover, when compared with the sum-product algorithm (SPA), the proposed decoding algorithm can achieve a reduction of 42%-67% of the total number of arithmetic operations required for the decoding process.

关键词： Computational complexity     Coding gain     Fast Fourier transform (FFT)     Low-density parity-check (LDPC) codes     Sum-product algorithm (SPA)    

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the ammonia oxidation capacity of ammonia-oxidizing archaeon originated from wastewater: Utilizing low-density

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1375-1

摘要：

• AOA’s ammonia oxidizing capacity was enhanced under moderate magnetic field.

关键词： Ammonia-oxidizing archaeon     Ammonia oxidation     Magnetic field     Magnetotaxis     Heredity    

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A low-density polyethylene composite with phosphorus-nitrogen based flame retardant and multi-walled

Yong Luo, Yuhui Xie, Renjie Chen, Ruizhi Zheng, Hua Wu, Xinxin Sheng, Delong Xie, Yi Mei

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1332-1345 doi: 10.1007/s11705-021-2035-0

摘要： Design and exploitation of flame retardant polymers with high electrical conductivity are desired for polymer applications in electronics. Herein, a novel phosphorus-nitrogen intumescent flame retardant was synthesized from pentaerythritol octahydrogen tetraphosphate, phenylphosphonyl dichloride, and aniline. Low-density polyethylene was combined with the flame retardant and multi-walled carbon nanotubes to form a nanocomposite material via a ball-milling and hot-pressing method. The electrical conductivity, mechanical properties, thermal performance, and flame retardancy of the composites were investigated using a four-point probe instrument, universal tensile machine, thermogravimetric analysis, and cone calorimeter tests, respectively. It was found that the addition of multi-walled carbon nanotubes can significantly improve the electrical conductivity and mechanical properties of the low-density polyethylene composites. Furthermore, the combination of multi-walled carbon nanotubes and phosphorus–nitrogen flame retardant remarkably enhances the flame retardancy of matrixes with an observed decrease of the peak heat release rate and total heat release of 49.8% and 51.9%, respectively. This study provides a new and effective methodology to substantially enhance the electrical conductivity and flame retardancy of polymers with an attractive prospect for polymer applications in electrical equipment.

关键词： MWCNTs     PEPA     electrical conductivity     flame retardant     low density polyethylene    

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Correlative investigation of copper/low-density polyethylene nanocomposite on the endometrial angiogenesis

LI Jianxiong, LIU Zilong, DUAN Yonggang, YU Jing, ZHU Changhong, LI Shuang, XIE Changsheng

《医学前沿（英文）》 2007年 第1卷 第4期   页码 401-404 doi: 10.1007/s11684-007-0078-3

摘要： The purpose of this study was to investigate the effects of copper/low-density polyethylene nanocomposite (nano-Cu/LDPE) on the endometrial angiogenesis in rats, and 100 sexual mature female SD rats were randomly divided into five groups: sham-operation groups (SO group, = 20), bulk copper groups (Cu group, = 20), LDPE groups ( = 20), nano-Cu/LDPE groups I ( = 20) and II ( = 20). The levels of angiopoietin-2 (Ang-2), its receptor (Tie-2) and CD34 of the rats endometria in each group were examined by using the S-P method of the immunohistochemistry 30 and 180 days after insertion, respectively. Compared with those in the SO group, the expression of Ang-2 and Tie-2 in all the experimental groups was obviously increased 30 days after insertion, and these parameters in nano-Cu/LDPE groups, except for Ang-2 level in nano-Cu/LDPE group II, were significantly lower in comparison with those in Cu group (<0.05). On the 180th day after insertion, Ang-2 and Tie-2 levels were still higher in Cu group and LDPE group, but there was no difference of Ang-2 and Tie-2 levels between nano-Cu/LDPE groups and the SO group (>0.05). Compared with those in the SO group, the significant increases in microvessel density (MVD) were observed on the 30th and the 180th day after the insertion of the bulk copper (<0.05). There was no significant difference in MVD counts before and after the insertion of nano-Cu/LDPE (>0.05). The results show that Nano-Cu/LDPE have slighter influence on the endometrial angiogenesis than bulk copper.

关键词： significant difference     female     endometrial angiogenesis     nano-Cu/LDPE     CD34    

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Quantum-dot cellular automata based reversible low power parity generator and parity checker design for

Jadav Chandra DAS,Debashis DE

《信息与电子工程前沿（英文）》 2016年 第17卷 第3期   页码 224-236 doi: 10.1631/FITEE.1500079

摘要： Quantum-dot cellular automata (QCA) is an emerging area of research in reversible computing. It can be used to design nanoscale circuits. In nanocommunication, the detection and correction of errors in a received message is a major factor. Besides, device density and power dissipation are the key issues in the nanocommunication architecture. For the first time, QCA-based designs of the reversible low-power odd parity generator and odd parity checker using the Feynman gate have been achieved in this study. Using the proposed parity generator and parity checker circuit, a nanocommunication architecture is proposed. The detection of errors in the received message during transmission is also explored. The proposed QCA Feynman gate outshines the existing ones in terms of area, cell count, and delay. The quantum costs of the proposed conventional reversible circuits and their QCA layouts are calculated and compared, which establishes that the proposed QCA circuits have very low quantum cost compared to conventional designs. The energy dissipation by the layouts is estimated, which ensures the possibility of QCA nano-device serving as an alternative platform for the implementation of reversible circuits. The stability of the proposed circuits under thermal randomness is analyzed, showing the operational efficiency of the circuits. The simulation results of the proposed design are tested with theoretical values, showing the accuracy of the circuits. The proposed circuits can be used to design more complex low-power nanoscale lossless nanocommunication architecture such as nano-transmitters and nano-receivers.

关键词： Quantum-dot cellular automata (QCA)     Parity generator     Parity checker     Feynman gate     Nanocommunication     Power dissipation    

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Performance of inverse fluidized bed bioreactor in treating starch wastewater

M. RAJASIMMAN, C. KARTHIKEYAN

《化学科学与工程前沿（英文）》 2009年 第3卷 第3期   页码 235-239 doi: 10.1007/s11705-009-0020-0

摘要： Aerobic digestion of starch industry wastewater was carried out in an inverse fluidized bed bioreactor using low-density (870 kg/m ) polypropylene particles. Experiments were carried out at different initial substrate concentrations of 2250, 4475, 6730, and 8910 mg COD/L and for various hydraulic retention times (HRT) of 40, 32, 24, 16, and 8 h. Degradation of organic matter was studied at different organic loading rates (OLR) by varying the HRT and the initial substrate concentration. From the results it was observed that the maximum COD removal of 95.6% occurred at an OLR of 1.35 kg COD/(m ·d) and the minimum of 51.8% at an OLR of 26.73 kg COD/(m ·d). The properties of biomass accumulation on the surface of particles were also studied. It was observed that constant biomass loading was achieved over the entire period of operation.

关键词： inverse fluidization     low-density particles     polypropylene     starch     biofilm    

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Empirical models and design codes in prediction of modulus of elasticity of concrete

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 38-48 doi: 10.1007/s11709-018-0479-1

摘要： Modulus of Elasticity (MOE) is a key parameter in reinforced concrete design. It represents the stress-strain relationship in the elastic range and is used in the prediction of concrete structures. Out of range estimation of MOE in the existing codes of practice strongly affect the design and performance of the concrete structures. This study includes: (a) evaluation and comparison of the existing analytical models to estimating the MOE in normal strength concrete, and (b) proposing and verifying a new model. In addition, a wide range of experimental databases and empirical models to estimate the MOE from compressive strength and density of concrete are evaluated to verification of the proposed model. The results show underestimation of MOE of conventional concrete in majority of the existing models. Also, considering the consistency between density and mechanical properties of concrete, the predicted MOE in the models including density effect, are more compatible with the experimental results.

关键词： modulus of elasticity     normal strength normal weight concrete     empirical models     design codes     compressive strength     density    

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Energy absorption potential of concrete floors containing secondary (shrinkage and temperature) reinforcements

K. S. SIVAKUMARAN,R. M. KOROL,Xiao FAN

《结构与土木工程前沿（英文）》 2014年 第8卷 第3期   页码 282-291 doi: 10.1007/s11709-014-0269-3

摘要： This paper experimentally investigates the energy absorption potential of two types of concrete floors, namely, normal density concrete and structural low-density concrete, containing secondary (shrinkage and temperature) reinforcements. The test program considered the following secondary reinforcements: 1) traditional welded-wire steel mesh, 2) steel fiber and 3) poly composite fiber. To estimate the extent to which crushing of floor slab materials would help absorb energy, a series of concrete penetration tests employing patch loading was undertaken on scaled down model slabs. Each concrete-secondary reinforcement combination considered slabs of 50 mm in depth with square plan dimensions ranging from 50 to 500 mm, resulting in a total of 30 test specimens. The first part of the paper discusses the test specimens, the test setup, and the test procedure. The second part of the paper presents the experimental results and establishes the energy absorption of different concrete- secondary reinforcement combinations. Sieve analysis results of the crushed specimens were used to derive a “work index” value that relates the pulverized particle size distributions to energy inputs. The work index values of concrete-secondary reinforcement systems can be used to assess the energy dissipation potential associated with such floor slabs in buildings undergoing progressive collapse. The results indicate that floors with secondary reinforcements could play an important role in helping arrest global progressive collapse.

关键词： concrete floors     structural low-density concrete     shrinkage and temperature reinforcements     energy absorption     penetration tests     sieve analysis    

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A prototype online database-enabled design framework for wind analysis/design of low-rise buildings

Dae Kun KWON,Ahsan KAREEM,Deepak KUMAR,Yukio TAMURA

《结构与土木工程前沿（英文）》 2016年 第10卷 第1期   页码 121-130 doi: 10.1007/s11709-015-0329-3

摘要： This study presents a development of an advanced cyberbased database-enabled design module for low-rise buildings (DEDM-LR) which provides estimation of the wind-induced responses for main wind force resisting frames by making direct use of pressure time histories measured at a large number of pressure taps over a suite of building models. These responses may be considered in lieu of code-specified load effects in which the overall accuracy may be influenced by the inherent simplifications in codes. In addition, this new automated approach is particularly attractive and advantageous as it allows a web-based online analysis/design via intuitive user-friendly interfaces for both the input and output in terms of familiar web-style forms that are nowadays very common in most of web-based services. Presently, the DEDM-LR hosts an aerodynamic database developed by the Tokyo Polytechnic University (TPU), Japan for a variety of building configurations like flat, gable, and hip roofs under suburban terrain flow condition with immediate application to other databases. The paper shows the efficacy and validity of the DEDM-LR by walking through its details and examples on selected gable-roofed buildings. The architecture of DEDM-LR platform offers the ability to pool resources by hosting other databases that may become available in the near future.

关键词： wind loads     low-rise building     pressure measurement     aerodynamics     building design     structural response     building codes     information technology (IT)    

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Design of packing cup interference fit value of hypercompressors for low density polyethylene production

Da LEI,Xuehong LI,Yun LI,Xiwen REN

《能源前沿（英文）》 2019年 第13卷 第1期   页码 107-113 doi: 10.1007/s11708-017-0450-1

摘要： The hypercompressor is one of the core facilities in low density polyethylene production, with a discharge pressure of approximately 300 MPa. A packing cup is the basic unit of cylinder packing, assembled by the interference fit between an inner cup and an outer cup. Because the shrink-fitting prestresses the packing cup, serious design is needed to gain a favorable stress state, for example, a tri-axial compressive stress state. The traditional method of designing the interference fit value for packing cups depends on the shrink-fit theory for thick-walled cylinder subject to internal and external pressure. According to the traditional method, critical points are at the inner radii of the inner and external cup. In this study, the finite element method (FEM) has been implemented to determine a more accurate stress level of packing cups. Different critical points have been found at the edge of lapped sealing surfaces between two adjacent packing cups. The maximum Von Mises equivalent stress in a packing cup increases after a decline with the rise of the interference fit value. The maximum equivalent stress initially occurs at the bore of the inner cup, then at the edge of lapped mating surfaces, and finally at the bore of the outer cup, as the interference radius increases. The traditional method neglects the influence of axial preloading on the interference mating pressure. As a result, it predicts a lower equivalent stress at the bore of the external cup. A higher interference fit value accepted by the traditional method may not be feasible as it might already make packing cups yield at the edge of mating surfaces or the bore of the external cup. Along with fatigue analysis, the feasible range of interference fit value has been modified by utilizing FEM. The modified range tends to be narrower and safer than the one derived from the traditional method, after getting rid of shrink-fit values that could result in yielding in a real packing cup.

关键词： interference fit value     packing cup     hypercompressor     finite element method (FEM)    

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Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要： A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词： steel     stress-strain characteristics     tension test     strain design     actual behavior     improved design codes    

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Improving retrieval precision of NO

Jinpeng YANG

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 92-96 doi: 10.1007/s11465-009-0001-5

摘要： The NO density error retrieved by the traditional method of differential optical absorption spectroscopy (DOAS) was analyzed. The technique for reducing the error is proposed and used to obtain the NO density of Chengdu through DOAS.

关键词： absorption structure     low-frequency structure     absorption cross-section     NO2 density    

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黄土高原典型流域淤地坝系泥沙拦截动态模拟 Article

孙彭成, 吴一平

《工程（英文）》 2023年 第27卷 第8期   页码 209-221 doi: 10.1016/j.eng.2021.12.015

摘要： 为此，本研究基于流域分布式水沙过程模拟，提出了流域淤地坝系拦沙量动态模拟框架，SWAT-DCDam (soil and water assessment tool-dynamic check dam)。

关键词： 淤地坝     淤地坝动态库容     黄土高原     淤地坝拦沙动态     SWAT模型    

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SOIL CARBON CHECK: A TOOL FOR MONITORING AND GUIDING SOIL CARBON SEQUESTRATION IN FARMER FIELDS

《农业科学与工程前沿（英文）》 2023年 第10卷 第2期   页码 248-261 doi: 10.15302/J-FASE-2023499

摘要：

● Establishment of a rapid tool for monitoring soil carbon sequestration in farmer fields.

关键词： 4 per 1000 initiative     carbon sequestration     climate action     farmer fields     SDG13     soil organic carbon     soil testing    

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Comparison and harmonization of building wind loading codes among the Asia-Pacific Economies

Yaojun GE, Shuyang CAO, Xinyang JIN

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 402-410 doi: 10.1007/s11709-013-0230-x

摘要： This paper reviews wind loading codes and standards in the Asia-Pacific Region, in particular in the 15 countries and areas. A general description of wind loading model is given as a famous wind loading chain described by four variables including velocity pressure, exposure factor, pressure coefficient, and gust response factor. Through the APEC-WW Workshops and the extensive calculations for three examples of low, medium and high rise buildings, these four important variables of wind loads are evaluated and compared with statistical parameters, mean values and coefficients of variation. The main results of the comparison show some differences among the 15 economies, and the reasons and further incorporation are discussed and suggested.

关键词： wind loading     codification     velocity pressure     exposure factor     pressure coefficient     gust response factor    

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标题 作者 时间 类型 操作

An improved low-complexity sum-product decoding algorithm for low-density parity-check codes

Michaelraj Kingston ROBERTS,Ramesh JAYABALAN

期刊论文

the ammonia oxidation capacity of ammonia-oxidizing archaeon originated from wastewater: Utilizing low-density

期刊论文

A low-density polyethylene composite with phosphorus-nitrogen based flame retardant and multi-walled

Yong Luo, Yuhui Xie, Renjie Chen, Ruizhi Zheng, Hua Wu, Xinxin Sheng, Delong Xie, Yi Mei

期刊论文

Correlative investigation of copper/low-density polyethylene nanocomposite on the endometrial angiogenesis

LI Jianxiong, LIU Zilong, DUAN Yonggang, YU Jing, ZHU Changhong, LI Shuang, XIE Changsheng

期刊论文

Quantum-dot cellular automata based reversible low power parity generator and parity checker design for

Jadav Chandra DAS,Debashis DE

期刊论文

Performance of inverse fluidized bed bioreactor in treating starch wastewater

M. RAJASIMMAN, C. KARTHIKEYAN

期刊论文

Empirical models and design codes in prediction of modulus of elasticity of concrete

Behnam VAKHSHOURI, Shami NEJADI

期刊论文

Energy absorption potential of concrete floors containing secondary (shrinkage and temperature) reinforcements

K. S. SIVAKUMARAN,R. M. KOROL,Xiao FAN

期刊论文

A prototype online database-enabled design framework for wind analysis/design of low-rise buildings

Dae Kun KWON,Ahsan KAREEM,Deepak KUMAR,Yukio TAMURA

期刊论文

Design of packing cup interference fit value of hypercompressors for low density polyethylene production

Da LEI,Xuehong LI,Yun LI,Xiwen REN

期刊论文

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

期刊论文

Improving retrieval precision of NO

Jinpeng YANG

期刊论文

黄土高原典型流域淤地坝系泥沙拦截动态模拟

孙彭成, 吴一平

期刊论文

SOIL CARBON CHECK: A TOOL FOR MONITORING AND GUIDING SOIL CARBON SEQUESTRATION IN FARMER FIELDS

期刊论文

Comparison and harmonization of building wind loading codes among the Asia-Pacific Economies

Yaojun GE, Shuyang CAO, Xinyang JIN

期刊论文