A Novel Resource Scheduling Scheme for CoMP Systems

( Wen`an Zhou ),( Jianlong Liu ),( Yiyu Zhang ),( Chengyi Yang ),( Xuhui Yang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.2

Coordinated multiple points transmission and reception (CoMP) technology is used to mitigate the inter-cell interference, and increase cell average user normalized throughput and cell edge user normalized throughput. There are two kinds of radio resource schedule strategies in LTE-A/5G CoMP system, and they are called centralized scheduling strategy and distributed scheduling strategy. The regional centralized scheduling cannot solve interference of inter-region, and the distributed scheduling leads to worse efficiency in the utilize of resources. In this paper, a novel distributed scheduling scheme named 9-Cell alternate authorization (9-CAA) is proposed. In our scheme, time-domain resources are divided orthogonally by coloring theory for inter-region cooperation in 9-Cell scenario [6]. Then, we provide a formula based on 0-1 integer programming to get chromatic number in 9-CAA. Moreover, a feasible optimal chromatic number search algorithm named CNS-9CAA is proposed. In addition, this scheme is expanded to 3-Cell scenario, and name it 3-Cell alternate authorization (3-CAA). At last, simulation results indicate that 9/3-CAA scheme exceed All CU CoMP, 9/3C CU CoMP and DLC resource scheduling scheme in cell average user normalized throughput. Especially, compared with the non-CoMP scheme as a benchmark, the 9-CAA and 3-CAA have improved the edge user normalized throughput by 17.2% and 13.0% respectively.

Investigation of Quench Sensitivity and Microstructure Evolution During Isothermal Treatment in 2195 Al–Li Alloy

Zhiwu Zhang,Youping Yi,Wen You,Shiquan Huang,Yonglin Guo,Hailin He 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

To investigate the quenching sensitivity of the 2195 Al–Li alloy rolled sheet and guide the design of the quenching process,the time–temperature-property (TTP) curves of this material were researched through interrupted quenching experiments. The differential scanning calorimetry (DSC) and transmission electron microscope (TEM) were used to characterize theevolution of precipitates during isothermal treatment. The results of this essay demonstrated that the nose temperature of 2195Al–Li alloy is around 370 °C and the temperature range of quenching sensitivity is 340 °C to 400 °C. The microstructureobservation revealed that the T1particles precipitate and grow rapidly at the temperature from 340 to 400 °C, which is dueto the high nucleation rate of phase and fast solute diffusion kinetics, especially at the nose temperature. The needle-shapedθ′/θ″ and T1particles grow up quickly as the isothermal preservation time prolonged, leading to the decrease of the supersaturatedsolid solution of the matrix. This will reduce the number of the age-induced precipitate and weaken the subsequentage hardening effect. Therefore, the rate of cooling should be increased in the quenching sensitivity range (340–400 °C) toinhibit the precipitation of the second phase and obtain excellent mechanical properties. While in other temperature ranges,the cooling rate should be decreased appropriately to reduce residual stress. The appropriate average cooling rate is recommendedto be around 13 °C s−1 at the temperature from 340 to 400 °C.

Enhancing Astaxanthin Accumulation in Haematococcus pluvialis by Coupled Light Intensity and Nitrogen Starvation in Column Photobioreactors

( Wen-wen Zhang ),( Xue-fei Zhou ),( Ya-lei Zhang ),( Peng-fei Cheng ),( Rui Ma ),( Wen-long Cheng ),( Hua-qiang Chu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at 200 μmo/m2/s under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

Characteristic Trend Analysis of Cancer Patients Hospitalized in Shanxi Tumor Hospital for the First Time during 2001 and 2010

Zhang, Wen-Li,Wang, Yan,Han, Cun-Zhi Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9

To observe and analyze the characteristic trend of cancer patients hospitalized for the first time in Shanxi Tumor Hospital from 2001 to 2010, clinical data including case number, age, gender, and frequency of different tumor occurrences were collected and statistically analyzed. Results: (i) From 2001 to 2010, the number of cancer patients hospitalized for the first time increased by 1.3-fold; (ii) The patient overall average age also increased from 51.8 to 54.4, for males from 55.5 to 58.7 and females from 48.4 to 51.1, respectively. (iii) Male patients accounted for 43-48% and females accounted for 52-57% of the total. The percentage of female patients was higher than that of male patients in every year and showed an upward trend over the years, while that of the males showed a downward trend (${\chi}^2=7.031$, p=0.008); (iv) Among the top 6 most common cancers, lung, cervical, esophageal, colorectal and breast cancers tended to increase over the years (p<0.05), but not gastric cancer (p=0.423). Conclusions: (i) The number of cancer patients hospitalized for the first time during the past 10 years increased year by year, and was higher for female than male; (ii) the average age of patients increased year after year and was greater for male than female; (iii) the number of patients with lung cancer, cervical cancer, esophageal cancer, colorectal cancer and breast cancer increased over years.

A Robust Fault Location Algorithm for Single Line-to-ground Fault in Double-circuit Transmission Systems

Wen-Hao Zhang,Umar Rosadi,Myeon-Song Choi,Seung-Jae Lee,Ilhyung Lim 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.1

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

Dynamic Response of a Graphene Oxide-Polyaniline Composite Suspension under an Applied Electric Field

Wen Ling Zhang,최형진 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

A suspension of semiconducting graphene oxide/polyaniline (GO/PANI) composite dispersed in silicone oil is considered as one of potential candidates for electrorheological (ER) fluids. The GO/PANI composite was synthesized by chemical oxidation polymerization of aniline in the presence of GO dispersion, in which the GO was prepared by a modified Hummers method. The characteristics of the composite were examined by SEM image and FT-IR spectra, indicating the coexistence of GO and PANI in the composite. The GO/PANI composite based ER fluid was prepared by dispersing the fabricated particles in silicone oil, and its dynamic viscoelastic properties were measured using a rotational rheometer under different electric field, showing that the ER fluid exhibited typical solid-like ER behaviors.

A Probabilistic Approach to the Protection Capability Evaluation of Distance Relay in Transmission Systems

Zhang, Wen-Hao,Lee, Seung-Jae,Choi, Myeon-Song The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.3

This paper proposes a probability measure for the evaluation of relay performance from two aspects, namely, correct trip and no-unwanted trip. They are developed based on the relationship between relay settings and relay measurements, which follow a Gaussian probability model. The proposed method based on strict mathematical derivation is applied to protection capability evaluation of distance relays under various settings. Considering the specific attributes of each protection zone, the optimal settings are also determined accordingly. The protection capability could demonstrate clearly the relay performance under various settings and the optimal settings could provide good references for engineering applications.

Setting Considerations of Distance Relay for Transmission Line with STATCOM

Zhang, Wen-Hao,Lee, Seung-Jae,Choi, Myeon-Song The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

A Robust Fault Location Algorithm for Single Line-to-ground Fault in Double-circuit Transmission Systems

Zhang, Wen-Hao,Rosadi, Umar,Choi, Myeon-Song,Lee, Seung-Jae,Lim, Il-Hyung The Korean Institute of Electrical Engineers 2011 Journal of Electrical Engineering & Technology Vol.6 No.1

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

Lateral-torsional Buckling Analysis of Cantilever Beam with Tip Lateral Elastic Brace under Uniform and Concentrated Load

Wen-Fu Zhang,Ying-Chun Liu,Gui-Lan Hou,Ke-Shan Chen,Jing Ji,Yun Deng,Shi-Lin Deng 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

The studies on the lateral-torsional buckling of cantilever steel beam with tip lateral elastic brace are rarely reported. The total potential energy is first established for the lateral-torsional buckling of cantilever steel beam with tip lateral elastic brace under uniform and concentrated load. The modal trial function of the lateral displacement and torsional angle are expressed as trigonometric function combination with six terms. By introducing new dimensionless parameters, the analytical solution of the dimensionless buckling equation for the lateral-torsional buckling of cantilever steel beam with tip lateral elastic brace is obtained. With the help of 1stOpt software which is mathematical optimization analysis software, the non-dimensional critical moment formula of the lateral-torsional buckling of cantilever beam with tip lateral elastic brace is obtained. Then, the accuracy of the formula is verified by ADINA finite element software. The results show that the given critical moment formula is of high accuracy. It provides convenient and simple design method for practical engineering.