Optimal Relay Selection and Power Allocation in an Improved Low-Order-Bit Quantize-and-Forward Scheme

( Jianrong Bao ),( Dan He ),( Xiaorong Xu ),( Bin Jiang ),( Minhong Sun ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.11

Currently, the quantize-and-forward (QF) scheme with high order modulation and quantization has rather high complexity and it is thus impractical, especially in multiple relay cooperative communications. To overcome these deficiencies, an improved low complex QF scheme is proposed by the combination of the low order binary phase shift keying (BPSK) modulation and the 1-bit and 2-bit quantization, respectively. In this scheme, the relay selection is optimized by the best relay position for best bit-error-rate (BER) performance, where the relays are located closely to the destination node. In addition, an optimal power allocation is also suggested on a total power constraint. Finally, the BER and the achievable rate of the low order 1-bit, 2-bit and 3-bit QF schemes are simulated and analyzed. Simulation results indicate that the 3-bit QF scheme has about 1.8~5 dB, 4.5~7.5 dB and 1~2.5 dB performance gains than those of the decode-and-forward (DF), the 1-bit and 2-bit QF schemes, at BER of 10^-2, respectively. For the 2-bit QF, the scheme of the normalized Source-Relay (S-R) distance with 0.9 has about 5dB, 7.5dB, 9dB and 15dB gains than those of the distance with 0.7, 0.5, 0.3 and 0.1, respectively, at BER of 10^-3. In addition, the proposed optimal power allocation saves about 2.5dB much more relay power on an average than that of the fixed power allocation. Therefore, the proposed QF scheme can obtain excellent features, such as good BER performance, low complexity and high power efficiency, which make it much pragmatic in the future cooperative communications.

A novel ceramic GEM used for neutron detection

Zhou, Jianrong,Zhou, Xiaojuan,Zhou, Jianjin,Jiang, Xingfen,Yang, Jianqing,Zhu, Lin,Yang, Wenqin,Yang, Tao,Xu, Hong,Xia, Yuanguang,Yang, Gui-an,Xie, Yuguang,Huang, Chaoqiang,Hu, Bitao,Sun, Zhijia,Chen, Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

A novel ceramic Gas Electron Multiplier (GEM) has been developed to meet the demand of high counting rate for the neutron detection which is an alternative to ³He-based detector at China Spallation Neutron Source (CSNS). An experiment was performed to measure the neutron transmittance of ceramic-GEM and FR4-GEM at the small angle neutron scattering (SANS) instrument. The result showed the ceramic-GEM has higher transmittance and less self-scattering especially for cold neutrons. One single ceramic GEM could give a gain of 10²-10⁴ in the mixture gas of Ar and CO₂ (90%:10%) and its energy resolution was about 27.7% by using ⁵⁵Fe X ray of 5.9 keV. A prototype has been developed in order to investigate the performances of the ceramic GEM-based neutron detector. Several neutron beam tests, including detection efficiency, spatial resolution, two-dimensional imaging, and wavelength spectrum, were carried out at CSNS and China Mianyang Research Reactor (CMRR). The results show that the ceramic GEM-based neutron detector is a good candidate to measure the high intensity neutrons.

Nanoclay, Intumescent Flame Retardants, and Their Combination with Chemical Modification for the Improvement of the Flame Retardant Properties of Polymer Nanocomposites

Guobo Huang,Jianguo Yang,Xu Wang,Jianrong Gao 한국고분자학회 2013 Macromolecular Research Vol.21 No.1

The flame retardancy of nanoclay, intumescent flame retardants (IFRs), and their combination with chemical modification is investigated in poly(methyl methacrylate) (PMMA) nanocomposites. 2,4,8,10-Tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N,N-triethyl-ammonium bromide (PDEABMMT)and 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N-dimethyl-N-hexadecyl-ammonium bromide (PDHAB-MMT) are prepared by ion exchange of sodium montmorillonite with phosphorus-nitrogen containing quarternary ammonium salts including PDEAB and PDHAB. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that PDHAB-MMT achieves tood dispersion in the PMMA matrix and the corresponding nanocomposites PMMA/PDHAB-MMT are formed. The incorporation of PDHAB-MMT into the PMMA matrix obviously improves the nanocomposite thermal properties. Cone calorimeter experiments indicate that the flame retardancy of nanoclay, IFRs, and their combination with chemical modification showed a 5%, 5%, and 9% reduction in the peak heat release rates of PMMA, respectively. The scanning electron microscopy and TEM images confirm that a compact and dense char is formed for PMMA/PDHAB-MMT nanocomposites after combustion.

Multi-orientation optimization of complex parts based on model segmentation in additive manufacturing

Hongshuai Guo,Jinghua Xu,Shuyou Zhang,Yiming Zhang,Jianrong Tan 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

Build orientation has a significant impact on the surface quality, support structure, and final cost of the fabricated model. In this study, we focus our attention on the surface quality and printing cost of complex parts when fabricated under multiple build orientations. A novel method using model segmentation is proposed to search for an optimal build orientation for each sub-model decomposed by Reeb graph. The sub-model is divided into separate regions that are treated differently based on modified curvature shift strategy. Every flat facet of the regions is given a different weight factor to build the volume error function. The optimal build orientation for each sub-model is the one leading to the minimal error of the volume error function. The case study demonstrates that the proposed method obtains a smaller error without any support structure. The model surface in higher weighted regions obtains a higher surface quality and is more cost saving when printed, especially for complex models.

Comparison of Monoexponential, Biexponential, Stretched-Exponential, and Kurtosis Models of Diffusion-Weighted Imaging in Differentiation of Renal Solid Masses

Jianjian Zhang,Shiteng Suo,Guiqin Liu,Shan Zhang,Zizhou Zhao,Jianrong Xu,Guangyu Wu 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.5

Objective: To compare various models of diffusion-weighted imaging including monoexponential apparent diffusion coefficient (ADC), biexponential (fast diffusion coefficient [Df], slow diffusion coefficient [Ds], and fraction of fast diffusion), stretched-exponential (distributed diffusion coefficient and anomalous exponent term [α]), and kurtosis (mean diffusivity and mean kurtosis [MK]) models in the differentiation of renal solid masses. Materials and Methods: A total of 81 patients (56 men and 25 women; mean age, 57 years; age range, 30–69 years) with 18 benign and 63 malignant lesions were imaged using 3T diffusion-weighted MRI. Diffusion model selection was investigated in each lesion using the Akaike information criteria. Mann–Whitney U test and receiver operating characteristic (ROC) analysis were used for statistical evaluations. Results: Goodness-of-fit analysis showed that the stretched-exponential model had the highest voxel percentages in benign and malignant lesions (90.7% and 51.4%, respectively). ADC, Ds, and MK showed significant differences between benign and malignant lesions (p < 0.05) and between low- and high-grade clear cell renal cell carcinoma (ccRCC) (p < 0.05). α was significantly lower in the benign group than in the malignant group (p < 0.05). All diffusion measures showed significant differences between ccRCC and non-ccRCC (p < 0.05) except Df and α (p = 0.143 and 0.112, respectively). α showed the highest diagnostic accuracy in differentiating benign and malignant lesions with an area under the ROC curve of 0.923, but none of the parameters from these advanced models revealed significantly better performance over ADC in discriminating subtypes or grades of renal cell carcinoma (RCC) (p > 0.05). Conclusion: Compared with conventional diffusion parameters, α may provide additional information for differentiating benign and malignant renal masses, while ADC remains the most valuable parameter for differentiation of RCC subtypes and for ccRCC grading.

FgIlv3a is crucial in branched-chain amino acid biosynthesis, vegetative differentiation, and virulence in Fusarium graminearum

Xin Liu,Yichen Jiang,Yinghui Zhang,Mingzheng Yu,Hongjun Jiang,Jianhong Xu,Jianrong Shi 한국미생물학회 2019 The journal of microbiology Vol.57 No.8

Dihydroxyacid dehydratase (DHAD), encoded by ILV3, catalyses the third step in the biosynthetic pathway of branchedchain amino acids (BCAAs), which include isoleucine (Ile), leucine (Leu), and valine (Val). Enzymes involved in BCAA biosynthesis exist in bacteria, plants, and fungi but not in mammals and are therefore attractive targets for antimicrobial or herbicide development. In this study, three paralogous ILV3 genes (FgILV3A, FgILV3B, and FgILV3C) were identified in the genome of Fusarium graminearum, the causal agent of Fusarium head blight (FHB). Deletion of FgILV3A alone or combined with FgILV3B or FgILV3C indicated an important role for FgILV3A in BCAA biosynthesis. FgILV3A deletion mutants lost the ability to grow on medium lacking amino acids. Exogenous supplementation of 1 mM Ile and Val rescued the auxotrophy of ΔFgIlv3A, though 5 mM was required to recover the growth defects in ΔFgIlv3AB and ΔFgIlv3AC strains, indicating that FgIlv3b and FgIlv3c exhibit redundant but accessory roles with FgIlv3a in BCAA biosynthesis. The auxotrophy of ΔFgIlv3A resulted in pleiotropic defects in aerial hyphal growth, in conidial formation and germination, and in aurofusarin accumulation. In addition, the mutants showed reduced virulence and deoxynivalenol production. Overall, our study demonstrates that FgIlv3a is crucial for BCAA biosynthesis in F. graminearum and a candidate fungicide target for FHB management.

Regeneration of full-scale commercial honeycomb monolith catalyst (V2O5–WO3/TiO2) used in coal-fired power plant

Xuesong Shang,Gongren Hu,Chi He,Jinping Zhao,Fuwang Zhang,Ya Xu,Yunfeng Zhang,Jianrong Li,Jinsheng Chen 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1

An effective and applicable method for the regeneration of used commercial full-scale honeycomb monolith catalysts in China (V2O5–WO3/TiO2) is firstly reported. The de-ionized water and dilute sulfuric acid solution with a relatively low concentration (pH = 2) are potent reagent to regenerated the catalysts used for about 30,000 h in coal-fired power plant. All samples were systematically characterized by TEM,N2 adsorption/desorption, EDX, FT-IR and XPS techniques. The evaluation results reveal that the activity of the used catalysts can be obviously improved after regeneration processes. Moreover, the regenerated catalysts possess superior activity under different gas hourly space velocity (GHSV), and SO2 oxidation rate is lower than 1% in all cases. The regeneration method can remove the deposits, restore active sites and prevent nanoparticles aggregation as well as active phases leaching. Overall, these processes have promised as effective approaches for industrial V2O5–WO3/TiO2 catalysts regeneration.

Numerical Investigation of Cracks at Girder Ends of Prefabricated Post-Tensioned Prestressed Concrete I-Girders

Aimin Yuan,Tongyi Wang,Jinjian Gu,Xinge Miao,Jianrong Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

Prefabricated post-tensioned prestressed concrete (PTC) girders with high degrees of prestressing have been developed continuously in recent bridge designs to reach longer spans, higher quality, and larger load-bearing capacity. However, during the prefabrication process, several inclined and horizontal cracks were observed at the ends of a new style post-tensioned concrete girder, which could have a negative impact on the girders' longevity. In this study, a nonlinear finite element analysis technique was utilized to illustrate how concrete reacts and the mechanisms behind typical cracking patterns during the actual post-tensioning sequence. The prestressing load of a PTC girder was simulated with an improved cooling temperature method that accounts for immediate prestress losses. The field of principle tensile strain patterns and primary strain trajectories explained the overall mechanism underlying typical cracking behaviors. The results showed that the horizontal cracks under the anchorage plate (behavior 1) were generated by the bursting force, whereas the inclined cracks (behavior 2) and the horizontal cracks between the strands N1 and N2 anchor plates (behavior 3) were caused due to the spalling force. The effects of self-weight, girder end forms, as well as the transfer length of the prestressing strands, were discussed. The result demonstrates that both the self-weight and girder end shapes have a considerable effect on the behaviors of the anchorage zone. It is suggested that the transfer length of the anchor head be greater than 26 times of strand diameter to achieve the same effective stresses as the theoretical values.