Entropy based Anomaly Detection and IP classification System to Prevent DDoS Attacks in Cloud Computing

Ziyi Zhang(장즈이),Oh YongTaek(오용택),Scott Uk-Jin Lee(이욱진) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.12

An Improved Plug-in Security Test Model for Web Application

Ziyi Zhang(장즈이),Scott Uk-Jin Lee(이욱진) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.6

Numerical compensation of system polarization mode dispersion in polarization-sensitive optical coherence tomography.

Zhang, Ellen Ziyi,Oh, Wang-Yuhl,Villiger, Martin L,Chen, Liang,Bouma, Brett E,Vakoc, Benjamin J Optical Society of America 2013 Optics express Vol.21 No.1

<P>Polarization mode dispersion (PMD), which can be induced by circulators or even moderate lengths of optical fiber, is known to be a dominant source of instrumentation noise in fiber-based PS-OCT systems. In this paper we propose a novel PMD compensation method that measures system PMD using three fixed calibration signals, numerically corrects for these instrument effects and reconstructs an improved sample image. Using a frequency multiplexed PS-OFDI setup, we validate the proposed method by comparing birefringence noise in images of intralipid, muscle, and tendon with and without PMD compensation.</P>

Research progress and the prospect of CO2 hydrogenation with dielectric barrier discharge plasma technology

Zhang Ziyi,Ding Honglei,Zhou Qi,Pan Weiguo,Qiu Kaina,Mu Xiaotian,Ma Junchi,Zhang Kai,Zhao Yuetong 한국탄소학회 2023 Carbon Letters Vol.33 No.4

In recent years, people are increasingly interested in CO2 hydrogenation to produce value-added chemicals and fuels (CH4, CH3OH, etc.). In the quest for an efficient treatment in CO2 methanation and methanolization, several technologies have been practiced, and DBD plasma technology gain attention due to its easily handling, mild operating conditions, strong activation ability, and high product selectivity. In addition, its reaction mechanism and the effect of packing materials and reaction parameters are still controversial. To address these problems efficiently, a summary of the reaction mechanism is presented. A discussion on plasma-catalyzed CO2 hydrogenation including packing materials, reaction parameters, and optimizing methods is addressed. In this review, the overall status and recent findings in DBD plasma-catalyzed CO2 hydrogenation are presented, and the possible directions of future development are discussed.

Ensemble of Convolution Neural Networks for Driver Smartphone Usage Detection Using Multiple Cameras

Ziyi Zhang,강보영 한국정보통신학회 2020 Journal of information and communication convergen Vol.18 No.2

Approximately 1.3 million people die from traffic accidents each year, and smartphone usage while driving is one of the main causes of such accidents. Therefore, detection of smartphone usage by drivers has become an important part of distracted driving detection. Previous studies have used single camera-based methods to collect the driver images. However, smartphone usage detection by employing a single camera can be unsuccessful if the driver occludes the phone. In this paper, we present a driver smartphone usage detection system that uses multiple cameras to collect driver images from different perspectives, and then processes these images with ensemble convolutional neural networks. The ensemble method comprises three individual convolutional neural networks with a simple voting system. Each network provides a distinct image perspective and the voting mechanism selects the final classification. Experimental results verified that the proposed method avoided the limitations observed in single camera-based methods, and achieved 98.96% accuracy on our dataset.

EFFECTS OF WATER INJECTION ON COMBUSTION EMISSION AND KNOCK CHARACTERISTICS OF TURBOCHARGED DIRECT INJECTION GASOLINE ENGINE

Fuwu Yan,Junjun Wang,Dong Yan,Wenlong Zhang,Guoqing Zhang,Jizhou Zhang,Ziyi Chen,Yu Wang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

This paper studied the effects of water injection on combustion, emissions and knock. The results showed that direct water injection (DWI) absorbed more heat than inlet port water injection (PWI), resulting in lower cylinder pressure, higher oxygen content and longer combustion duration. And the turbulence kinetic energy of DWI model was greater, resulting in lower soot and CO emissions of DWI. Furthermore, the cooling effect of exhaust port side WI was better than intake port side, which reduced NOX emission. Besides, the injection pressure of single injector WI was higher than double injector, which increased the combustion duration and reduced the cylinder pressure. The decrease of temperature under water dilution was the main reason for the reduction of NOX, while the increase of incomplete combustion increased the soot and CO emission. Finally, with the same amount of WI, the knock suppression effect of DWI models was better than PWI models. The knock intensity (KI) of all models decreased gradually with the increase of water, and DWI models decreased more rapidly. For PWI models, when the amount of water became smaller, the engine pressure fluctuation of certain areas in the cylinder increased slightly, weakening the influence of WI on engine knock.

Gut microbiota derived from fecal microbiota transplantation enhances body weight of Mimas squabs

Ren Jing,Li Yumei,Ni Hongyu,Zhang Yan,Zhao Puze,Xiao Qingxing,Hong Xiaoqing,Zhang Ziyi,Yin Yijing,Li Xiaohui,Zhang Yonghong,Yang Yuwei 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.8

Objective: Compared to Mimas pigeons, Shiqi pigeons exhibit greater tolerance to coarse feeding because of their abundant gut microbiota. Here, to investigate the potential of utilizing intestinal flora derived from Shiqi pigeons, the intestinal flora and body indices of Mimas squabs were evaluated after fecal microbiota transplantation (FMT) from donors.Methods: A total of 90 one-day-old squabs were randomly divided into the control group (CON), the low-concentration group (LC) and the high-concentration group (HC): gavaged with 200 μL of bacterial solution at concentrations of 0, 0.1, and 0.2 g/15 mL, respectively.Results: The results suggested that FMT improved the body weight of Mimas squabs in the HC and LC groups (p<0.01), and 0.1 g/15 mL was the optimal dose during FMT. After 16S rRNA sequencing was performed, compared to those in the CON group, the abundance levels of microflora, especially Lactobacillus, Muribaculaceae, and Megasphaera (p<0.05), in the FMT-treated groups were markedly greater. Random forest analysis indicated that the main functions of key microbes involve pathways associated with metabolism, further illustrating their important role in the host body.Conclusion: FMT has been determined to be a viable method for augmenting the weight and intestinal microbiota of squabs, representing a unique avenue for enhancing the economic feasibility of squab breeding. Objective: Compared to Mimas pigeons, Shiqi pigeons exhibit greater tolerance to coarse feeding because of their abundant gut microbiota. Here, to investigate the potential of utilizing intestinal flora derived from Shiqi pigeons, the intestinal flora and body indices of Mimas squabs were evaluated after fecal microbiota transplantation (FMT) from donors. Methods: A total of 90 one-day-old squabs were randomly divided into the control group (CON), the low-concentration group (LC) and the high-concentration group (HC): gavaged with 200 μL of bacterial solution at concentrations of 0, 0.1, and 0.2 g/15 mL, respectively. Results: The results suggested that FMT improved the body weight of Mimas squabs in the HC and LC groups (p<0.01), and 0.1 g/15 mL was the optimal dose during FMT. After 16S rRNA sequencing was performed, compared to those in the CON group, the abundance levels of microflora, especially Lactobacillus, Muribaculaceae, and Megasphaera (p<0.05), in the FMT-treated groups were markedly greater. Random forest analysis indicated that the main functions of key microbes involve pathways associated with metabolism, further illustrating their important role in the host body. Conclusion: FMT has been determined to be a viable method for augmenting the weight and intestinal microbiota of squabs, representing a unique avenue for enhancing the economic feasibility of squab breeding.

SET/PP2A signaling regulates macrophage positioning in hypoxic tumor regions by amplifying chemotactic responses

Zhang Shaolong,Zhou Jingping,Shang Pengzhao,Zhao Guomeng,Wang Anlei,Mao Jinlei,Tao Yuhang,Chen Ziyi,Wang Xuehao,Guo Changying 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Tumor-associated macrophages (TAMs) are one of the main cellular components in the tumor microenvironment (TME). In many types of solid tumors, TAMs tend to accumulate in hypoxic areas and are intimately related to poor patient prognosis. However, the underlying mechanisms by which TAMs infiltrate hypoxic tumor regions remain unclear. In this study, we report that genetic deletion of SE translocation (SET) in myeloid cells inhibited the entry of TAMs into the hypoxic tumor region and abated their proangiogenic and immunosuppressive functions, ultimately inhibiting tumor growth. Mechanistically, in response to hypoxic tumor supernatant stimulation, SET in macrophages shuttled between the nucleus and cytoplasm via the PKC-CK2α signaling axis. Cytoplasmic retention of SET increased ERK and P38 signaling by inhibiting PP2A, which promoted TAM migration into the hypoxic area and polarization toward the M2 phenotype. Therefore, we conclude that SET modulates tumor immunity by acting as a key regulator of macrophage positioning and function in the tumor.

일회성 운동 중 초미세먼지(PM2.5) 과흡입이 마우스 폐의 염증 및 세포사멸 반응에 미치는 영향

염동진,Ziyi Zhang,박진한,장준호,소병훈,이강규,강청훈 한국운동생리학회 2023 운동과학 Vol.32 No.4

PURPOSE: The purpose of this study was to investigate the effects of hyperventilation in the presence of fine particulate matter (PM2.5) on inflammatory and apoptotic responses in the lungs of mice during a single bout of aerobic exercise. METHODS: The FVB/N mice were housed in a controlled SPF room and randomly divided into four groups: control (CON, n=7), fine particulate matter exposure (PM, n=7), PM and exercise (PME, n=7), and exercise only (EX, n=7). Acute PM exposure and/or aerobic treadmill exercise were undertaken according to the groups using a specially designed PM treadmill chamber. RESULTS: Protein expression and phosphorylation of p65 NF-kB in mouse lungs were significantly increased by acute exercise, but not by PM exposure. Basal protein levels and phosphorylation of MAPKs (p38, ERK, and JNK) were significantly increased in the PME group, but were lower in the PM and EX groups. Although the percentage of collagen fibers in lung tissue was not affected by PM exposure, the expression of pro- and antiapoptotic factors BAX, BID, and Bcl-2 was significantly elevated by inhalation of PM during exercise. CONCLUSIONS: In this study, the MAPKs family was activated by excessive PM inhalation during exercise and similar changes in apoptosis-related signaling were observed. This suggests that even a single bout of inhalation of fine particulate matter during exercise can affect factors associated with inflammation and cell death.

Heat transfer of a sustainable personal garment cooling system

Yijie Zhang,Ziyi Guo,Tao Li,Yexin Lyu,FengYuan Zou 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

This paper provides examines sustainable personal cooling systems. The impact of micro-fan configuration and inflow airspeed was tested. First, three different types of test models-a garment with side seam micro-fans, scatter-fans, and bottom-fans, was used to analyze and compare the heat transfer characteristic. Second, a new index of convective heat transfer was used to evaluate the cooling performance of these models. Third, the selected model was calculated with three different inflow properties, and the performance of efficiency and energy saving was analyzed. The results show that the bottom-fans model yields the best performance both on efficiency and cooling effect. The evaluation of thermal environment shows that the defined indexes are reliable to reflect heat transfer characteristics in the air gap. The comparison study of different airspeeds shows that the inflow air velocity should be set at a suitable range due to the view of energy saving.