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      • KCI등재

        A reversible data hiding scheme in JPEG bitstreams using DCT coefficients truncation

        ( Mingming Zhang ),( Quan Zhou ),( Yanlang Hu ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.1

        A reversible data hiding scheme in JPEG compressed bitstreams is proposed, which could avoid decoding failure and file expansion by means of removing of bitstreams corresponding to high frequency coefficients and embedding of secret data in file header as comment part. We decode original JPEG images to quantified 8×8 DCT blocks, and search for a high frequency as an optimal termination point, beyond which the coefficients are set to zero. These blocks are separated into two parts so that termination point in the latter part is slightly smaller to make the whole blocks available in substitution. Then spare space is reserved to insert secret data after comment marker so that data extraction is independent of recovery in receiver. Marked images can be displayed normally such that it is difficult to distinguish deviation by human eyes. Termination point is adaptive for variation in secret size. A secret size below 500 bits produces a negligible distortion and a PSNR of approximately 50 dB, while PSNR is also mostly larger than 30 dB for a secret size up to 25000 bits. The experimental results show that the proposed technique exhibits significant advantages in computational complexity and preservation of file size for small hiding capacity, compared to previous methods.

      • Carpooling Service for Large-Scale Taxicab Networks

        Zhang, Desheng,He, Tian,Zhang, Fan,Lu, Mingming,Liu, Yunhuai,Lee, Haengju,Son, Sang H. Association for Computing Machinery 2016 ACM transactions on sensor networks Vol.12 No.3

        <P>Carpooling has long held the promise of reducing gas consumption by decreasing mileage to deliver coriders. Although ad hoc carpools already exist in the real world through private arrangements, little research on the topic has been done. In this article, we present the first systematic work to design, implement, and evaluate a carpool service, called coRide, in a large-scale taxicab network intended to reduce total mileage for less gas consumption. Our coRide system consists of three components, a dispatching cloud server, passenger clients, and an onboard customized device, called TaxiBox. In the coRide design, in response to the delivery requests of passengers, dispatching cloud servers calculate cost-efficient carpool routes for taxicab drivers and thus lower fares for the individual passengers. To improve coRide's efficiency in mileage reduction, we formulate an NP-hard route calculation problem under different practical constraints. We then provide (1) an optimal algorithm using Linear Programming, (2) a 2-approximation algorithm with a polynomial complexity, and (3) its corresponding online version with a linear complexity. To encourage coRide's adoption, we present a win-win fare model as the incentive mechanism for passengers and drivers to participate. We test the performance of coRide by a comprehensive evaluation with a real-world trial implementation and a data-driven simulation with 14,000 taxi data from the Chinese city Shenzhen. The results show that compared with the ground truth, our service can reduce 33% of total mileage; with our win-win fare model, we can lower passenger fares by 49% and simultaneously increase driver profit by 76%.</P>

      • KCI등재

        MODEL-BASED CONTROL OF SYNCHRONIZER SHIFTING PROCESS FOR TRAJECTORY TRACKING CONTROL

        Yan Zhang,Han Zhao,Mingming Qiu,Feifei Qin,Bingzhan Zhang 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.4

        A novel approach of the tracking control for synchronizer displacement is introduced in this paper. Based on modeling for the structure of synchronizer and shifting process, a shifting displacement tracking controller is designed by the Udwadia - Kalaba equation. The engagement rule of synchronizer combination sleeve is regarded as the trajectory constraint of the system, certain constraint force is imposed to follow this trajectory constraint, which could be obtained by the Udwadia- Kalaba equation without using Lagrange multiplier or other auxiliary variables. Specific comparative study with conventional PID control is discussed. Simulations and vehicle test results show that the shifting actuator can accurately track the desired trajectory determined by the upper layer control strategy, thus verify the effectiveness of the controller.

      • KCI등재

        Influence of Partial Replacement of NaCl with KCl on Formation of Volatile Compounds in Jinhua Ham during Processing

        Yingyang Zhang,Haizhou Wu,Jing Tang,Mingming Huang,Jianying Zhao,Jianhao Zhang 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.2

        The influence of partial replacement of NaCl with KCl on formation of volatile compounds during Jinhua ham processing was evaluated using GC/MS system. Jinhua ham was treated with either 100% NaCl (I) or 60% NaCl and 40% KCl (II). Formation of volatile compounds increased in Jinhua hams during processing for both salt formulations, particularly at the end of the salting period. There were differences in volatile compound formation between formulations I and II after 45 days of processing. Contents of lipid-derived volatiles (hexanal) and Strecker aldehydes (2-methylbutanal and 3- methylbutanal) were higher in Jinhua hams treated with formulation II after 45 days of processing. Partial salt replacement of NaCl with KCl changed formation of volatile compounds in Jinhua hams and may have affected the flavor of finished products.

      • KCI등재

        Isolation and characterization of heat-responsive gene TaGASR1 from wheat (Triticum aestivum L.)

        Liyuan Zhang,Xiaoli Geng,Haiyan Zhang,Chunlei Zhou,Aiju Zhao,Fei Wang,Yue Zhao,Xuejun Tian,Zhaorong Hu,Mingming Xin,Yingyin Yao,Zhongfu Ni;Qixin Sun,Qixin Sun,Huiru Peng 한국식물학회 2017 Journal of Plant Biology Vol.60 No.1

        GA-stimulated transcript (GAST) family genes have been identified in numerous plant species. In this paper, we isolated and characterized a heat-responsive gene, TaGASR1, from heat tolerant variety TAM107. The complete ORF of TaGASR1 was cloned, which encoded a 98-kDa protein, and the sequence shared 51.52% similarity to OsGASR1. Analysis of the TaGASR1 promoter region showed that it contained a heat shock element (HSE) and several cis-elements involved in abiotic stress response and hormone signal transduction. Expression patterns of TaGASR1 revealed that it was strongly induced by stress factors, such as high temperature, drought, high salinity and oxidation, as well as the phytohormones, including MeJA, ACC and ABA, which suggested the TaGASR1 gene might participate in these stress and hormone signal transduction pathways. Transient expression of TaGASR1-GFP fusion proteins in onion epidermal cells indicated that TaGASR1 protein was localized to the cell membrane or cytosol. Further analysis showed that ectopic expression of TaGASR1 in Arabidopsis enhanced thermotolerance and reduced the accumulation of reactive oxygen species (ROS) after heat stress. Moreover, we also found that TaGASR1-overexpressing wheat improved tolerance to heat stress and oxidative stress.

      • KCI등재

        Kinetics of Horseradish Peroxidase-Catalyzed Nitration of Phenol in a Biphasic System

        ( Mingming Kong ),( Yang Zhang ),( Qida Li Runan Dong ),( Haijun Gao ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.2

        The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and NO<sub>2</sub> - and H<sub>2</sub>O<sub>2</sub> as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or H<sub>2</sub>O<sub>2</sub> (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter V<sub>max</sub>/K<sub>m</sub>. No inhibition of enzyme activity was observed when the concentrations of phenol and H<sub>2</sub>O<sub>2</sub> were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were K<sub>m</sub> <sup>H2O2</sup> = 1.09 mM, K<sub>m</sub> <sup>PhOH</sup> = 9.45 mM, and V<sub>max</sub> = 0.196 mM/min. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

      • KCI등재

        Three-dimensional dynamics simulation analysis of high clearance sprayer with road excitation

        Mingming Xing,Xiaoguang Li,Kaifeng Xue,Chengmao Zhang,Zongxiang Hou 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

        The stability of a high clearance sprayer (HCS) can be considered in developing modern agriculture. We built a three-dimensional dynamics model of HCS with road excitation considering the influence of complex terrain on the whole vehicle vibration. The numerical simulation method was proposed to solve differential equations based on the Newmark-β method. The response curves of whole vehicle in the time and frequency domain response were analyzed. The simulation results show that the vibration amplitude difference of left and right wheel is bigger than amplitude difference of right and rear wheel. The average amplitude of roll motion is bigger than pitching motion. The reason is that since the man-machine seat is set on the left of whole vehicle, an additional roll torque is brought. Besides, the displacement amplitude of whole vehicle is bigger than man-machine seat. The reason is that the vibration absorption system of seat can reduce vibration effectively. In amplitude-frequency response curves, the multiple resonance points occur with the road excitation given in this paper. The maximum response amplitude of angle velocity and acceleration of pitching motion is bigger than roll motion. This study has an important theoretical and practical value for structure dynamic optimization of HCS.

      • SCIESCOPUSKCI등재

        Topology and start-up strategy for DC-DC transformers based on voltage balancing unit

        Zhang, Jialin,Zha, Kunpeng,Tang, Xiaojun,Yang, Yuefeng,Yan, Hui,Wen, Fuyue,Shi, Mingming The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.7

        As a core piece of equipment in DC distribution networks, DC solid-state transformers (DCSSTs) are attracting more and more attention in academia and industry. Due to the limitations in terms of the electrical stress of the switches, the input series output parallel (ISOP) structure is adopted in DCSSTs. This paper proposed an improved DCSST topology based on a voltage balancing unit (VBU). This topology has the advantages of higher power density, reduced weight, and cascaded number without compromising efficiency, cost, or reliability. The working modes, mathematical models, and control strategy are analyzed. In addition, a start-up strategy and a parameter design method are proposed in this paper. Simulation and experimental results verify the correctness and effectiveness of the proposed solution. The proposed DCSST is a practical scheme for the application of DC distribution networks.

      • KCI등재

        Experimental Study on Mechanical Properties of Continuous Welding Stainless Steel Roof System under Temperature Effect

        Mingming Wang,Tong Ou,Zhiyong Xin,Dayang Wang,Yongshan Zhang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

        Stainless steel is used as a new generation of long-span metal roof systems with continuous welding technology, which exhibits many unknown behaviors during temperature action. This study focuses on the temperature effect of a continuous welded stainless steel roof (CWSSR) system and analyzes the stress distribution of plate rib (PR), plate surface (PS), and support (SU), and the horizontal and vertical displacement. Furthermore, the thermal action of the CWSSR system is comprehensively analyzed considering different loading rates, constant temperature time, and the cycle number. Research results show that the stress concentration and thermal expansion of the CWSSR system are obvious, and fatigue damage occurs under long-term temperature action. The responses of the CWSSR system are greatly influenced by the loading rate and the cycle number but are less influenced by the constant temperature time. Loading rate and the cycle number mainly affect the plate surface stress and vertical displacement. The plate surface stress and vertical displacement peak increased by 34.6% and 29.6% with the loading rate, and changed by 32.4% and 42.5% with the cycle number. Cyclic loading reduces support tensile capacity by 4.4%. The research results can provide reference for the design and application of temperature field resistance of the CWSSR system.

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