A Function Network Analyzer for Efficient Analysis of Automotive Operating System

( Lu Zhengyu ),( Yunja Choi ) 한국정보처리학회 2013 한국정보처리학회 학술대회논문집 Vol.20 No.1

This work developed a code analysis & extraction tool named Function Network Analyzer (FNA) to reduce the cost of software safety analysis. FNA analyzes functions and variables which a given functio-n depends on, and extracts subset of code that can be compiled of automotive operating system, final res-ulting a well-ordered code sequence that can be compiled for model checking technique. And the experi-mental result illustrates that FNA can get 100% accurate rate and over 96% reduction rate by testing AP-I functions from trampoline system.

Effects of Different Levels of Supplementary Alpha-amylase on Digestive Enzyme Activities and Pancreatic Amylase mRNA Expression of Young Broilers

Jiang, Zhengyu,Zhou, Yanmin,Lu, Fuzeng,Han, Zhaoyu,Wang, Tian Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.1

Four hundred and forty 1-day-old Arbor Acre broilers were fed commercial starter diets with 0, 250, 750 and 2,250 mg/kg of an alpha-amylase preparation from 1 to 21 days of age to investigate the effects of an exogenous enzyme on growth performance, activities of digestive enzymes in the pancreas and anterior intestinal contents and pancreatic amylase mRNA expression. Body weight gain (BWG) and average daily gain (ADG) increased linearly (p<0.01) with increasing levels of supplementary amylase but feed conversion ratio (FCR) was not affected. There was a negative quadratic change of protease and amylase in the small intestinal contents with the increase of supplementary amylase level. The activity of intestinal trypsin was also increased (p<0.05). Lipase was unaffected by amylase supplementation (p>0.05). The pancreatic protease, trypsin, and lipase were not affected by exogenous amylase levels. Consistent with the tendency for a linear depression of amylase activity, pancreatic ${\alpha}$-amylase mRNA was down-regulated by dietary amylase supplementation. The present study suggested that oral administration of exogenous amylase affected activities of intestinal enzymes and the production of pancreatic digestive enzymes in a dose-dependent manner.

Co-DDTMA : Cooperative Distributed TDMA for Vehicular Networks

Zhen Chen,Zhengyu Liu,Jianghong Han,Songhua Hu,Yang Lu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.2

In recent years, Vehicular Ad Hoc Networks (VANET) has experienced a rapid development due to the advancement of wireless communication technologies, and now emerges as a promising way to provide road safety, traffic efficiency and infotainment applications. However, it is a challenge to design a reliable and efficient Medium Access Control (MAC) protocol for VANET due to its frequent topology changes and unreliable wireless links. Cooperative communication, on the other hand, can enhance the reliability of wireless links by exploiting the broadcast nature of the wireless communication. A cooperative scheme for MAC is proposed for VANET in this paper, referred to as Cooperative Distributed TDMA (Co-DTDMA). In the Co-DTDMA, neighboring nodes utilize its idle slots for cooperatively retransmitting a packet which has failed to reach the destination. Since the cooperative retransmission is conducted in node's own idle slot, the proposed scheme does not interrupt the normal transmission. Both theoretical analysis and simulation results demonstrate that the proposed scheme greatly increases the probability of successful packet transmission and decreases the packet transmission delay.

Novel Five-Level Three-Phase Hybrid-Clamped Converter with Reduced Components

Bin Chen,Wenxi Yao,Zhengyu Lu 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

This study proposes a novel five-level three-phase hybrid-clamped converter composed of only six switches and one flying capacitor (FC) per phase. The capacitor-voltage-drift phenomenon of the converter under the classical sinusoidal pulse width modulation (SPWM) strategy is comprehensively analyzed. The average current, which flows into the FC, is a function of power factor and modulation index and does not remain at zero. Thus, a specific modulation strategy based on space vector modulation (SVM) is developed to balance the voltage of DC-link and FCs by injecting a common-mode voltage. This strategy applies the five-segment method to synthesize the voltage vector, such that switching losses are reduced while optional vector sequences are increased. The best vector sequence is then selected on the basis of the minimized cost function to suppress the divergence of the capacitor voltage. This study further proposes a startup method that charges the DC-link and FCs without any additional circuits. Simulation and experimental results verify the validity of the proposed converter, modulation strategy, and precharge method.

Novel Five-Level Three-Phase Hybrid-Clamped Converter with Reduced Components

Chen, Bin,Yao, Wenxi,Lu, Zhengyu The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

This study proposes a novel five-level three-phase hybrid-clamped converter composed of only six switches and one flying capacitor (FC) per phase. The capacitor-voltage-drift phenomenon of the converter under the classical sinusoidal pulse width modulation (SPWM) strategy is comprehensively analyzed. The average current, which flows into the FC, is a function of power factor and modulation index and does not remain at zero. Thus, a specific modulation strategy based on space vector modulation (SVM) is developed to balance the voltage of DC-link and FCs by injecting a common-mode voltage. This strategy applies the five-segment method to synthesize the voltage vector, such that switching losses are reduced while optional vector sequences are increased. The best vector sequence is then selected on the basis of the minimized cost function to suppress the divergence of the capacitor voltage. This study further proposes a startup method that charges the DC-link and FCs without any additional circuits. Simulation and experimental results verify the validity of the proposed converter, modulation strategy, and precharge method.

Input Voltage Range Extension Method for Half-Bridge LLC Converters by Using Magamp Auxiliary Post-Regulator

Xiaoguang Jin,Huipin Lin,Jun Xu,Zhengyu Lu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

An improved half-bridge LLC converter with a magamp auxiliary post-regulator is proposed in this paper. The function of themagamp is bypassed when the converter works within the low input-voltage range. Meanwhile, it operates as an auxiliarypost-regulator when the input voltage is high. By changing the blocking time of the magamp, the dc gain of the converter can beextended. Hence, the input voltage range of the converter is extended. The realization of proposed topology does not require acomplicated circuit. The controller of the magamp can be easily implemented using only passive components, transistors and anOP amp. The generalized operational principle is analyzed and the design criterion for the magamp is presented. Finally, a 25Voutput, 400W experimental prototype was built and tested for a 160–300V input-voltage range to verify the feasibility of theproposed method.

Input Voltage Range Extension Method for Half-Bridge LLC Converters by Using Magamp Auxiliary Post-Regulator

Jin, Xiaoguang,Lin, Huipin,Xu, Jun,Lu, Zhengyu The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

An improved half-bridge LLC converter with a magamp auxiliary post-regulator is proposed in this paper. The function of the magamp is bypassed when the converter works within the low input-voltage range. Meanwhile, it operates as an auxiliary post-regulator when the input voltage is high. By changing the blocking time of the magamp, the dc gain of the converter can be extended. Hence, the input voltage range of the converter is extended. The realization of proposed topology does not require a complicated circuit. The controller of the magamp can be easily implemented using only passive components, transistors and an OP amp. The generalized operational principle is analyzed and the design criterion for the magamp is presented. Finally, a 25V output, 400W experimental prototype was built and tested for a 160-300V input-voltage range to verify the feasibility of the proposed method.

A Self-Tuning Notch Filter Based Hybrid Active Damper for LCLType Grid-Tied Inverters with Adaptability to Weak Grids

Zheyu Miao,Sun Long,Wenxi Yao,Zhengyu Lu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

LCL-filters are widely used in grid-tied converters for improved attenuations and lower costs. To prevent instability, the LCL resonance peak needs to be damped by the active dampers that avoid the dissipations but increase the control complexity. In the weak grid, the harmonic currents and the grid impedance variations make the control become more complicated and difficult. The influence of the harmonic currents and the grid impedance in parallel system is researched in this paper. Then, a selftuning notch filter (STNF) is introduced, and the resonance peak identification process implemented in digital controller is proposed in detailed. The consumption and tracking error of the STNF are analyzed guaranteeing an effective design. By adopting the STNF, the local maximum gain frequency is estimated online in response to the grid inductance variations. The construction as well as optimal design principles of the hybrid active damper are proposed in detail. To further reject the harmonic voltage effects, a PR regulator with a harmonic compensation controller is adopted. A step-by-step example design of the controller is illustrated in detail. The online implementation in DSP controllers and the digitization influence of the proposed method are also amply discussed. Finally, simulation and experimental results verify the effectiveness of the proposed method.

Chronic Virus Infection Enforces Demethylation of the Locus that Encodes PD-1 in Antigen-Specific CD8⁺ T Cells

Youngblood, Ben,Oestreich, Kenneth ,J.,Ha, Sang-Jun,Duraiswamy, Jaikumar,Akondy, Rama ,S.,West, Erin ,E.,Wei, Zhengyu,Lu, Peiyuan,Austin, James ,W.,Riley, James ,L.,Boss, Jeremy&nb Elsevier 2011 Immunity Vol.35 No.3

<P><B>Summary</B></P><P>Functionally exhausted T cells have high expression of the PD-1 inhibitory receptor, and therapies that block PD-1 signaling show promise for resolving chronic viral infections and cancer. By using human and murine systems of acute and chronic viral infections, we analyzed epigenetic regulation of PD-1 expression during CD8<SUP>+</SUP> T cell differentiation. During acute infection, naive to effector CD8<SUP>+</SUP> T cell differentiation was accompanied by a transient loss of DNA methylation of the <I>Pdcd1</I> locus that was directly coupled to the duration and strength of T cell receptor signaling. Further differentiation into functional memory cells coincided with <I>Pdcd1</I> remethylation, providing an adapted program for regulation of PD-1 expression. In contrast, the <I>Pdcd1</I> regulatory region was completely demethylated in exhausted CD8<SUP>+</SUP> T cells and remained unmethylated even when virus titers decreased. This lack of DNA remethylation leaves the <I>Pdcd1</I> locus poised for rapid expression, potentially providing a signal for premature termination of antiviral functions.</P> <P><B>Highlights</B></P><P>► <I>Pdcd1</I> locus demethylation is coupled to naive to effector CD8<SUP>+</SUP> T cell differentiation ► After <I>Pdcd1</I> remethylation, select CpGs remain unmethylated in memory CD8<SUP>+</SUP> T cells ► Exhausted virus-specific CD8<SUP>+</SUP> T cells retain an unmethylated <I>Pdcd1</I> regulatory region ► Human CD8<SUP>+</SUP> T cells specific to chronic viruses retain an unmethylated <I>PDCD1</I> locus</P>