A 4th-Order Low-distortion Low-pass ΣΔ Modulator Using Timing-Sharing Technique

Hong-guo Zhang,Ji-bao Zhang,Ming-yuan Ren 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

A 4th-Order low-distortion low-pass ΣΔ modulator structure is proposed in this paper, which uses the timing-sharing between the 3rd and 4th integrators during one clock phase. Compared with conventional cascade of integrators with distributed feed-forward (CIFF) sigma-delta modulator structure, the proposed structure not only solves the critical timing issue for the quantizer and feedback DAC path, but also eliminates an extra active adder to sum up the input feed-forward. By methods of delay redistribution structure, the time for quantization and feedback dynamic element match (DEM) operation can be extended from a non-overlapping interval for a conventional low-distortion structure to half of the sampling clock period. Capacitive input feed-forward (CIF) methodology eliminates the adder in front of the quantizer. Further, the op-amp of the last integrator is used as an active adder by op-amp sharing. Therefore, the power consumption can be reduced and the linearity of the feedback DAC is improved because of the increasing time which used for implementation of DEM algorism. The proposed 4th-Order low-distortion low-pass ΣΔ modulator with 4-bit quantizer is simulated in MATLAB. From the simulation results, the proposed structure can achieve a peak SNR (signal- to-noise ratio) of 87dB with 2.5MHz bandwidth under 32 oversampling ratio at 160MHz sampling frequency and the ENOB of 14.234bits in non-ideal condition.

LDA를 이용한 온라인 리뷰의 다중 토픽별 감성분석 - TripAdvisor 사례를 중심으로 -

홍태호 ( Hong Tae-ho ),니우한잉 ( Niu Hanying ),임강 ( Ren Gang ),박지영 ( Park Ji-young ) 한국정보시스템학회 2018 情報시스템硏究 Vol.27 No.1

Purpose There is much information in customer reviews, but finding key information in many texts is not easy. Business decision makers need a model to solve this problem. In this study we propose a multi-topic sentiment analysis approach using Latent Dirichlet Allocation (LDA) for user-generated contents (UGC). Design/methodology/approach In this paper, we collected a total of 104,039 hotel reviews in seven of the world's top tourist destinations from TripAdvisor (www.tripadvisor.com) and extracted 30 topics related to the hotel from all customer reviews using the LDA model. Six major dimensions (value, cleanliness, rooms, service, location, and sleep quality) were selected from the 30 extracted topics. To analyze data, we employed R language. Findings This study contributes to propose a lexicon-based sentiment analysis approach for the keywords-embedded sentences related to the six dimensions within a review. The performance of the proposed model was evaluated by comparing the sentiment analysis results of each topic with the real attribute ratings provided by the platform. The results show its outperformance, with a high ratio of accuracy and recall. Through our proposed model, it is expected to analyze the customers’ sentiments over different topics for those reviews with an absence of the detailed attribute ratings.

Path Planning for Vehicle Active Collision Avoidance Based on Virtual Flow Field

Liu Jian,Ji Jie,Ren Yue,Huang Yanjun,Wang Hong 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.6

According to the inherent nature of the fluid that can naturally avoid obstacles, a path planning method for active collision avoidance of autonomous vehicles is presented based on the virtual flow field. Firstly, the mathematical model of the virtual flow field on the road is established by using the theory of hydrodynamics. Then a fifth degree polynomial curve is adopted to construct the virtual hazard area of the obstacle vehicle to prevent the fluid into this area, and it can be easily resized by adjusting the parameters of the lateral and longitudinal safety distance. Finally, Computational Fluid Dynamics (CFD) simulations are performed to quantitative predict the dynamic behavior of the ego vehicle on the straight or curved road and the desired path for active collision avoidance can be determined based on the calculation result of the flow field. The simulation results show that the proposed path planning method takes into account the dynamic characteristics and kinematic constraints of the vehicle, and ensures that the vehicle doesn’t collide with the dynamic and static obstacles on the road.

The New Ecosystem of Cross-border E-Commerce among Korea, China and Japan Based on Blockchain

Xiang-Dong Shen,Xi Chen,Ran Ji,Ren-Hong Wu 한국무역학회 2020 Journal of Korea trade Vol.24 No.5

Purpose - The purpose of the study is to propose a theoretical framework of cross-border e-commerce ecosystems based on blockchain technology. The ecosystem includes five systems, namely, crossborder supply chain intelligent system, cross-border logistics system, cross-border payment system, cross-border product quality traceability system and cross-border customs supervision system. Design/methodology - This study firstly derived the main improvement factors for the new ecosystem based on blockchain through prior research and expert interviews on cross-border e-commerce. Then explored the use of virtue of decentralization, anti-counterfeiting traceability, consensus mechanism, smart contract and other means of the core technology of blockchain to overcome the bottleneck of cross-border e-commerce development among Korea, China, and Japan. Finally, proposed valuable implications in both theoretical and practical perspectives. Findings - As a result, we combined with the problems existing in cross-border e-commerce among Korea, China and Japan, this paper proposes a solution based on blockchain. On this basis, it constructs a cross-border e-commerce ecosystem among these three countries, including five systems. In addition, we discuss the main problems existing in the current blockchain, such as low transaction concurrency, security loopholes, and inconsistent standards, the corresponding countermeasures are proposed from the technical level, security level and industry standards. Originality/value - This study is the first to apply the blockchain technology to solve the cross-border e-commerce problems in Korea, China and Japan, which is of pioneering significance in both literature and practice. Block chain technology is in the ascendency. This study provides technical solutions for promoting the development of cross-border e-commerce import and export trade between Korea, China and Japan.

Optimal Design for Cooling System of Batteries Using DOE and RSM

Zhen-Zhe Li,Yun-De Shen,Tai-Hong Cheng,Dong-Ji Xuan,Ming Ren,Gui-Ying Shen 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

A hybrid power composed of fuel cell and batteries has become the good strategy for HEV. On the contrary, the produced heat of batteries can affect to the total performance of HEV significantly. In this study, simulation methods with optimization were developed for obtaining the high performance cooling system of batteries. At first, a numerical method for obtaining the temperature distribution of batteries was developed by using CFD. In the following step, several parameters were investigated for selecting design variables with the important effect on the performance of the cooling system of batteries. Finally, an optimization method based on DOE and RSM was obtained through a real optimal design. There was 21.1% reduction on the view of the root mean square temperature between batteries as shown in the optimization result. The developed analysis with optimization can be used to improve the performance of the cooling system of batteries, and these works have made the theoretical basis for simulation and optimization of the cooling system of batteries.

Paint Removal of Airplane & Water Jet Application

Xue, Sheng-Xiong,Chen, Zheng-Wen,Ren, Qi-Le,Su, Ji-Xin,Han, Cai-Hong,Pang, lei Korean Society for Fluid machinery 2014 International journal of fluid machinery and syste Vol.7 No.3

The paint removal and recoating are the very important process in airplane maintenance. The traditional technology is to use the chemical way corroding the paint with paint remover. For changing the defects, corrosion & pollution & manual working, of the traditional technology, the physical process which removes the paint of airplane with 250MPa/250kW ultra-high pressure rotary water jetting though the surface cleaner installed on the six axes robot is studied. The paint layer of airplane is very thin and close. The contradiction of water jetting paint removal is to remove the paint layer wholly and not damage the surface of airplane. In order to solve the contradiction, the best working condition must be reached through tests. The paint removal efficiency with ultra-high pressure and move speed of not damaged to the surface. The move speed of this test is about 2m/min, and the paint removal efficiency is about $30{\sim}40m^2/h$, and the paint removal active area is 85-90%. No-repeat and no-omit are the base requests of the robot program. The physical paint removal technology will be applied in airplane maintenance, and will face the safety detection of application permission.

Apoptosis Induction Effects of EGCG in Laryngeal Squamous Cell Carcinoma Cells through Telomerase Repression

Xi Wang,Miao-Wang Hao,Ke Dong,Fang Lin,Ji-Hong Ren,Hui-Zhong Zhang 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.9

Epigallocatechin-3-gallate (EGCG), the major component of green tea polyphenol, has potent efficiency to prevent the growth of a variety of cancer cells. As a novel anticancer agent for treatment of cancers, EGCG is promising and the mechanism has not been fully understood. Laryngeal squamous cell carcinoma (LSCC) is one common tumor in head and neck cancers. In the present study, we assess the effects of EGCG on LSCC cell line Hep-2, and their possible involvement in EGCG-induced apoptosis. The result showed that treatment of Hep-2 cells with EGCG decreased the cell viability, inhibited the growth and proliferation, induced apoptosis and increased the activity of caspase-3 in a dose-dependent manner. Furthermore, we found that EGCG-treatment repressed telomerase activity effectively in a concentrationdependent manner. The combined results show that EGCG induced apoptosis in Hep-2 cells via inhibiting the telomerase activity.

Injectable Cell Delivery Vehicle and Polymeric Conductive Constructs for Myocardial Tissue Engineering

Meng-Hsuan HSIEH,Congyu ZHANG,Song-Yi WU,Shu-Hong LI,Jun WU,Shi-Ming LIU,Hao-Ji WEI,Ren Ke LI,Hsing-Wen SUNG 한국생물공학회 2019 한국생물공학회 학술대회 Vol.2019 No.4

중국 흑룡강성 간흡충증 관리사업(2001-2004)

지주오,이즈민,왕수유,위안런,거타오,위안샹,추이창위안,거홍안,평정,슈롱치,홍성태,최민호,조승열,최동일,홍광선,임한종,이순형,Ji, Zhuo,Li, Zhimin,Wang, Shuyu,Yuan, Ren,Ge, Tao,Yuan, Shang,Cui, Changyuan,Ge, Hongan,Feng, Zheng,Xu, Longqi,Hong, Sung-Tae,Choi, 한국건강관리협회 2005 한국건강관리협회지 Vol.3 No.1

The present pilot project was executed to recommend a strategy of clonorchiasis control in China. The pilot area of this project was Zhaoyuan, Hailin, and Ningan, Heiloagjiang province. A baseline survey subjecting 4,865 residents in Heilongjiang confirmed Zhaoyuan asa high endemic area and Hailin and Ningan as moderate endemic areas. Six different control strategies were implemented in Zhaoyuan, two were in Hailin, and one was in Ningan. Including the baseline survey and project programs from 2000 to 2004, total 63,274subject-times were examined of their feces for Clonorchiseggs, 26,680 were treated, 10,082 were screened by ELISA, and 6,130 subjects were examined of their liver by sonography. The egg Positive rates in 6 villages of Zhaoyuan were as high as 44.8% 70,0%. Following the protocolof each strategy, the subjected residents were examined of their feces and treated with 25 mg/kg praziquantel, 3 times. Except the control group, all of the villages showed 72.8% to 92.0% reduction of their original egg Positive rates at Zhaoyuan. Mass treatments of all subjected residents in 2001 and 2003 reduced the egg rate from 68.8% to18.7% and 4 annual mass treatments reduced the rate from 44.8% in 2001 to 8.7% in 2004.Selective annual treatments of egg positive subjects reduced the egg rates from 50.8% in2001 to 13.8% in 2004 or from 70.0% in 2001 to 11.6% in 2004, and two treatments in a year reduced the rate from 57.6% in 2001 to 4.6% in 2004. According to repeated treatments, EPG counts decreased remarkably. In moderate endemic areas, the original egg rates were 22.6% and 28.3% in 2001 but were 1.7% and 1.1% after 2 or 3 selective treatments. The present findings of the chemotherapeutic control of clonorchiasis prove that repeated medication is important. The reduction is directly correlated with dose of praziquantel but not with mass or selective treatments. Chemotherapeutic control of reservoirhosts has little effect on reinfection of clonorchiasis because the field along the Songhua-jiang is too wide to be impacted. ELISA confirmed many serologically positive cases to Clonorchisantigen but only a few cases were positive to other antigens (Paragonimus, cysticercus, sparganum). The abdominal soaography visualized intrahepatic bile duct dilatation and periductal echo in 2,002 of 6,070 examined subjects. In addition to these examinations and treatment, health education supplemented tㅗe control activities. The present findings prove clonorchiasis is very widely prevalent and heavily endemic along the rivers in Heiloagjiang. The results suggest that group chemotherapy with praziquantel is effective to reduce endemicity of clonorchiasis. Mass treatment without individual fecal examination is recommended in heavy endemic areas where the egg rate is over 40% while one selective treatment is effective enough in moderate endemic areas.