A Study of Power Distribution between Engine and Motor for a CVT Based Parallel Hybrid Electric Vehicle

Jian Ji,Chao Ma,Hyunsoo Kim(김현수) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

In this paper, an optimal control strategy on how to distribute the demanded vehicle power to the engine and motor for a CVT based parallel hybrid electric vehicle is proposed. The purpose of this strategy is to find the optimized CVT gear ratio to maximize the integrated efficiency of the engine and motor. Although considerable fuel economy is achieved, depletion of battery energy occurs since the optimal strategy takes the motor as a primary power source and distributes the demanded vehicle power to the motor as much as possible. To solve this problem, a practical modification is made for the proposed control strategy. Modified control strategy takes the engine as a primary power source and distributes the demanded vehicle power to the engine as much as possible. It is found from the simulation results that 2.3% improvement of the fuel economy is achieved by the modified control strategy compared with that of a weight factor based power assist control algorithm.

Development of Torque Converter Lockup Performance Evaluation Environment using SimulationX

Jian Ji,Oheun Kwon,Sangwon Lee,Jaeduk Jang,Hyunsoo Kim 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

In this paper, a lockup performance evaluation environment is developed using SimulationX by considering the engine vibration and the shaft torsional resistance. Every shaft is modeled as damper-spring system and the engine output torque is modeled as the sum of average torque and vibration torque. Using the performance evaluation environment, the torque converter lockup performance is investigated by changing various design specifications, i.e. spring rate, travel, hysteresis of the lockup clutch damper system. It is found that the torque converter lockup performances can be evaluated effectively in terms of driveline vibration.

Motor Control of a Parallel Hybrid Electric Vehicle

Jian Ji,Chao Ma,Hyunsoo Kim 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

In this paper, a control strategy of a CVT based parallel hybrid electric vehicle is proposed. The control strategy is developed based on the assumption that the energy flow from/to the motor/battery within a successive deceleration and acceleration process is equal. For power distribution between the motor and engine, first, the motor power is determined from the viewpoint of battery energy balance and, then, the remaining power is supplied by the engine. In this way, improved fuel economy is achieved since more regenerative braking energy can be recuperated and both the motor and engine operate in a higher efficiency region compared with that of the power assist control algorithm. It is found from the simulation results that almost symmetric motor (generator) performance is observed in the motor speed/torque/efficiency map and 5.1% improvement of the fuel economy is achieved by the proposed strategy.

A k-means++ Algorithm for Internet Shopping Search Engine

( Jian-ji Ren ),( Jae-kee Lee ) 한국정보처리학회 2008 한국정보처리학회 학술대회논문집 Vol.15 No.2

Nowadays, as the indices of the major search engines grow to a tremendous proportion, vertical search services can help customers to find what they need. Search Engine is one of the reasons for Internet shopping success in today’s world. The import one part of search engine is clustering data. The objective of this paper is to explore a k-means++ algorithm to calculate the clustering data which in the Internet shopping environment. The experiment results shows that the k-means++ algorithm is a faster algorithm to achieved a good clustering.

Macroslip detection for a metal V-belt continuously variable transmission using the period difference

Ji, Jian,Jang, Mijeong,Ahn, Sunghyun,Kwon, Oheun,Chai, Minjae,Lee, Donghyun,Kim, Hyunsoo Professional Engineering Publishing Ltd 2015 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>In this study, a macroslip detection method is proposed for a metal V-belt continuously variable transmission. The macroslip detection method was developed using the instantaneous periods of the primary pulley’s acceleration and the secondary pulley’s acceleration, which can be obtained from the existing speed sensors. To obtain the instantaneous periods of the accelerations of the pulleys in real time, a signal-processing method was developed on the basis of zero-cross detection. Using the instantaneous periods, the period difference is introduced, and a threshold value <I>b</I> is defined to evaluate the slip state. The characteristics of the period difference and <I>b</I> were investigated by a three-dimensional analysis, in which a three-dimensional model of the continuously variable transmission including the blocks, the bands and the pulleys was constructed, and the velocity of each element and the slip rate were obtained. From the simulation results, it was found that the period difference stays below the threshold value <I>b</I> in the microslip region and begins to increase over the threshold value <I>b</I> in the macroslip region. The macroslip detection method proposed in this study was validated by experiments, which showed that the method is effective for detecting the occurrence of macroslip, independently of the input torque and the speed ratio.</P>

An Efficient and Provable Secure Certificateless Identification Scheme in the Standard Model

( Ji-jian Chin ),( Swee-huay Heng ),( Raphael C. -w. Phan ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.7

In Asiacrypt 2003, Al-Riyami and Paterson proposed the notion of certificateless cryptography, a technique to remove key escrow from traditional identity-based cryptography as well as circumvent the certificate management problem of traditional public key cryptography. Subsequently much research has been done in the realm of certificateless encryption and signature schemes, but little to no work has been done for the identification primitive until 2013 when Chin et al. rigorously defined certificateless identification and proposed a concrete scheme. However Chin et al.`s scheme was proven in the random oracle model and Canetti et al. has shown that certain schemes provable secure in the random oracle model can be insecure when random oracles are replaced with actual hash functions. Therefore while having a proof in the random oracle model is better than having no proof at all, a scheme to be proven in the standard model would provide stronger security guarantees. In this paper, we propose the first certificateless identification scheme that is both efficient and show our proof of security in the standard model, that is without having to assume random oracles exist.

Research Note: A New Record of Penicillium cainii from Soil in Korea

( Jian Xin Deng ),( Seung Hyun Ji ),( Narayan Chandra Paul ),( Ji Hye Lee ),( Seung Hun Yu ) 한국균학회 2013 Mycobiology Vol.41 No.2

Twenty Penicillium isolates were recovered during the investigation of fungal community in the soil samples collected from Wando (Jeonnam Province, Korea). Among them, one species was identified and described as P. cainii based on phylogentic analysis of internal transcribed spacer and β-tubulin (BT2) genes and morphological characteristics. This is a first report of P. cainii in Korea.

VotingRank: A Case Study of e-Commerce Recommender Application Using MapReduce

( Jian-ji Ren ),( Jae-kee Lee ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.1

There is a growing need for ad-hoc analysis of extremely large data sets, especially at e-Commerce companies which depend on recommender application. Nowadays, as the number of e-Commerce web pages grow to a tremendous proportion; vertical recommender services can help customers to find what they need. Recommender application is one of the reasons for e-Commerce success in today’s world. Compared with general e-Commerce recommender application, obviously, general e-Commerce recommender application’s processing scope is greatly narrowed down. MapReduce is emerging as an important programming model for large-scale data-parallel applications such as web indexing, data mining, and scientific simulation. The objective of this paper is to explore MapReduce framework for the e-Commerce recommender application on major general and dedicated link analysis for e-Commerce recommender application, and thus the responding time has been decreased and the recommender application’s accuracy has been improved.

Tetrandrine Exerts a Radiosensitization Effect on Human Glioma through Inhibiting Proliferation by Attenuating ERK Phosphorylation

( Ji-wei Ma ),( Yong Zhang ),( Ji-cheng Ye ),( Ru Li ),( Yu-lin Wen ),( Jian-xian Huang ),( Xue-yun Zhong ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.2

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to have a radiosensitization effect on tumors. However, its effects on human glioma and the specific molecular mechanisms of these effects remain unknown. In this study, we demonstrated that Tet has a radiosensitization effect on human glioma cells. It has been hypothesized that Tet has a radiosensitization effect on glioma cells by affecting the glioma cell cycle and DNA repair mechanism and that ERK mediates these activities. Therefore, we conducted detailed analyses of the effects of Tet on the cell cycle by performing flow cytometric analysis and on DNA repair by detecting the expression of phosphorylated H2AX by immunofluorescence. We used western blot analysis to investigate the role of ERK in the effect of Tet on the cell cycle and DNA repair. The results revealed that Tet exerts its radiosensitization effect on glioma cells by inhibiting proliferation and decreasing the expression of phosphorylated ERK and its downstream proteins. In summary, our data indicate that ERK is involved in Tet-induced radiosensitization of glioma cells via inhibition of glioma cell proliferation or of the cell cycle at G0/G1 phase.

Removal of phenanthrene from soil by additive-enhanced electrokinetics

Ji-Yeon Park,Yan Chen,Jian Chen,Ji-Won Yang 한국지질과학협의회 2002 Geosciences Journal Vol.6 No.1

Removal of hydrophobic organic contaminants(HOCs) using an additive-enhanced electrokinetic method wasstudied in a model system. Kaolinite and phenanthrene wereselected as a model clay soil and a representative HOC, respec-tively. Three different chemically-synthesized surfactants alongwith two diferent biosurfactants were used to remove phenan-threne. Hydrogen peroxide was also used to degrade phenan-threne. Electrokinetic (EK) column experiments were performedusing these additives. When no additive was used, a removal effi-ciency of phenanthrene was 4.23% after 2 weks. When surfac-tants were added in the EK system, the removal efficiencies after2 weeks were as follows: APG 11.1%, Brij30 6.31%, SDS 9.97%,MEL 16.2% and BS-UC 17.4%. Among surfactants, biosurfac-tants had higher removal efficiencies than chemically-synthesizedsurfactants. When hydrogen peroxide was used, 54.7% of initialamount was removed at a current of 5 mA for 2 weeks. Even ahigher removal efficiency was achieved (84.2%) at 10 mA within1 week. These results suggest a detailed future study on the chem-ical treatment by hydrogen peroxide incorporated with EK methodto remove phenanthrene from clay soil.