An Improved K-means Algorithm based on Mapreduce and Grid

Li Ma,Lei Gu,Bo Li,Yue Ma,Jin Wang 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.1

The traditional K-means clustering algorithm is difficult to initialize the number of clusters K, and the initial cluster centers are selected randomly, this makes the clustering results very unstable. Meanwhile, algorithms are susceptible to noise points. To solve the problems, the traditional K-means algorithm is improved. The improved method is divided into the same grid in space, according to the size of the data point property value and assigns it to the corresponding grid. And count the number of data points in each grid. Selecting M(M>K) grids, comprising the maximum number of data points, and calculate the central point. These M central points as input data, and then to determine the k value based on the clustering results. In the M points, find K points farthest from each other and those K center points as the initial cluster center of K-means clustering algorithm. At the same time, the maximum value in M must be included in K. If the number of data in the grid less than the threshold, then these points will be considered as noise points and be removed. In order to make the improved algorithm can adapt to handle large data. We will parallel the improved k-mean algorithm and combined with the MapReduce framework. Theoretical analysis and experimental results show that the improved algorithm compared to the traditional K-means clustering algorithm has high quality results, less iteration and has good stability. Parallelized algorithm has a very high efficiency in data processing, and has good scalability and speedup.

The Waveform Model of Laser Altimeter System with Flattened Gaussian Laser

Ma Yue,Wang Mingwei,Yang Fanlin,Li Song 한국광학회 2015 Current Optics and Photonics Vol.19 No.4

The current waveform model of a laser altimeter is based on a Gaussian laser beam of fundamentalmode, while the flattened Gaussian beam has many advantages such as nearly constant energy distributionon the center of the cross-section. Following the theory of the flattened Gaussian beam and the waveformtheory of the laser altimeter, some of the primary parameters of the received waveform were derived, anda laser altimetry waveform simulator and waveform processing software were programmed and improvedunder the circumstance of a flattened Gaussian beam. The result showed that the bias between theoreticaland simulated waveforms was less than 3% for every order mode, the waveform width and range errorwould increase as target slope or order number rose. Under higher order mode, the shapes of the receivedwaveforms were no longer Gaussian, and could be fitted more precisely as a generalized Gaussian functionwith power bigger than 2. The flattened beam got much better performance for a multi-surface target,especially when the small surface is far from the center of the laser footprint. This article provides thewaveform theoretical basis for the use of a flattened Gaussian beam in a laser altimeter

Bifurcation of Combinatorial Oscillations in Coupled Duffing's Circuits

Yue MA,Hiroshi KAWAKAMI 대한전자공학회 2002 ITC-CSCC :International Technical Conference on Ci Vol.2002 No.7

Influence of lining materials on the detonation driving of fragments

Yue Ma,Yong He,Chuan Ting Wang,Yuan He,Cheng Ji,Lei Guo,Peng Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

The shape and strength of prefabricated fragments changes to some extent after detonation loading. In this paper, detonation loading process of prefabricated fragments under two types of lining layers was studied and compared with no lining. By observing the recovered fragments, it was found that the inner part of the material was cracked and the shape of the fragments changed significantly. Comparing the two lining materials, the Kevlar/epoxy was better protective lining than polyurethane. The detonation process was analyzed qualitatively by using shock wave theory. In order to further explore the process, the simulation software LS-DYNA was used to carry out 3D simulation. The simulation results, in good agreement with the experimental results, showed that the Kevlar/Epoxy liner had a great influence on the initial velocity of the fragment. The experimental results and simulation results suggest that spherical fragments are better than cylindrical fragments in detonation drive application.

ON THE DISCREPANCY OF CORONAL MAGNETIC FIELDS IN SOLAR OPTICS AND RADIO

MA YUE-HuA,LI XIAO-QING The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1

It is analysed the discrepancy about the coronal magnetic field between solar optic and solar radio using magnetic fibril concept with filling factor and fractal structure model. The magnetic field of $\~$ 100 G considered in solar optics is mean value in a large scale, and that of $\~$1000 G in solar should be the value of fine structures inside 'macro' loop.

Radiomics of Non-Contrast-Enhanced T1 Mapping: Diagnostic and Predictive Performance for Myocardial Injury in Acute ST-Segment-Elevation Myocardial Infarction

Ma Quanmei,Ma Yue,Yu Tongtong,Sun Zhaoqing,Hou Yang 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.4

Objective: To evaluate the feasibility of texture analysis on non-contrast-enhanced T1 maps of cardiac magnetic resonance (CMR) imaging for the diagnosis of myocardial injury in acute myocardial infarction (MI). Materials and Methods: This study included 68 patients (57 males and 11 females; mean age, 55.7 ± 10.5 years) with acute ST-segment-elevation MI who had undergone 3T CMR after a percutaneous coronary intervention. Forty patients of them also underwent a 6-month follow-up CMR. The CMR protocol included T2-weighted imaging, T1 mapping, rest first-pass perfusion, and late gadolinium enhancement. Radiomics features were extracted from the T1 maps using open-source software. Radiomics signatures were constructed with the selected strongest features to evaluate the myocardial injury severity and predict the recovery of left ventricular (LV) longitudinal systolic myocardial contractility. Results: A total of 1088 segments of the acute CMR images were analyzed; 103 (9.5%) segments showed microvascular obstruction (MVO), and 557 (51.2%) segments showed MI. A total of 640 segments were included in the 6-month follow-up analysis, of which 160 (25.0%) segments showed favorable recovery of LV longitudinal systolic myocardial contractility. Combined radiomics signature and T1 values resulted in a higher diagnostic performance for MVO compared to T1 values alone (area under the curve [AUC] in the training set; 0.88, 0.72, p = 0.031: AUC in the test set; 0.86, 0.71, p = 0.002). Combined radiomics signature and T1 values also provided a higher predictive value for LV longitudinal systolic myocardial contractility recovery compared to T1 values (AUC in the training set; 0.76, 0.55, p < 0.001: AUC in the test set; 0.77, 0.60, p < 0.001). Conclusion: The combination of radiomics of non-contrast-enhanced T1 mapping and T1 values could provide higher diagnostic accuracy for MVO. Radiomics also provides incremental value in the prediction of LV longitudinal systolic myocardial contractility at six months.

Biosynthesis and uptake of glycine betaine as cold-stress response to low temperature in fish pathogen Vibrio anguillarum

Yue Ma,Qiyao Wang,Xiating Gao,Yuanxing Zhang 한국미생물학회 2017 The journal of microbiology Vol.55 No.1

Fish pathogen Vibrio anguillarum, a mesophile bacterium, is usually found in estuarine and marine coastal ecosystems worldwide that pose a constant stress to local organism by its fluctuation in salinity as well as notable temperature change. Though V. anguillarum is able to proliferate while maintain its pathogenicity under low temperature (5–18°C), so far, coldadaption molecular mechanism of the bacteria is unknown. In this study, V. anguillarum was found possessing a putative glycine betaine synthesis system, which is encoded by betABI and synthesizes glycine betaine from its precursor choline. Furthermore, significant up-regulation of the bet gene at the transcriptional level was noted in log phase in response to cold-stress. Moreover, the accumulation of betaine glycine was only found appearing at low growth temperatures, suggesting that response regulation of both synthesis system and transporter system are cold-dependent. Furthermore, in-frame deletion mutation in the two putative ABC transporters and three putative BCCT family transporters associated with glycine betaine uptake could not block cellular accumulation of betaine glycine in V. anguillarum under coldstress, suggesting the redundant feature in V. anguillarum betaine transporter system. These findings confirmed that glycine betaine serves as an effective cold stress protectant and highlighted an underappreciated facet of the acclimatization of V. anguillarum to cold environments.

북중관계를 통해 본 정상회담의 연속성과 단절성: 뉴스 프레임 내용 분석을 중심으로

마월 ( Ma Yue ),박성호 ( Park Seongho ),김용호 ( Kim Yongho ) 한국외국어대학교 국제지역연구센터 2022 국제지역연구 Vol.26 No.2

이 연구는 김정일, 김정은 시기 북한과 중국의 정상회담 개최에 연속성과 단절성이 있으며, 연속성은 북한의 대미접근에서, 단절성은 한중관계 개선에서 비롯된다고 주장한다. 중국의 제안으로 양 시기 첫 정상회담이 개최됨에 주목해, 중국이 인식하는 북중관계를 구체화함으로써 연구 주장을 입증하고자 했다. 인민일보에 대한 뉴스 프레임 분석 결과, 김정일 시기 전통적 친선관계 계승, 대북 무상원조 등의 긍정적 내용이 주를 이룬 반면, 김정은 시기 전략적 협력관계 강화, 북핵반대 등 중립적이거나 부정적 보도가 많이 나타나는 차이를 포착했다. 이와 같은 차이에도 양 시기 모두 ‘한국’과 ‘북한의 대미접근’이 북중정상회담의 중요 변수로 작동한다는 공통점을 발견했다. This paper argues that there is continuity and discontinuity between China and North Korea during the Kim Jong-il and Kim Jong-un periods. The former stems from North Korea's approach to the United States, and the latter emerges from improved China-South Korea relations. Since the suggestion of China holds the first summit in the two periods, we tried to prove the research argument by shaping the Sino-North Korean relationship recognized by China. As a result of News Framing Analysis on the People's Daily, we found positive content, such as the inheritance of traditionally friendly relations and free aid to North Korea during the Kim Jong-il period, while neutral or negative reports in Kim Jong-un period, like strengthening strategic cooperation and opposing North Korea. Despite these differences, we figured out something in common that "South Korea" and "North Korea's approach to the United States" work as essential variables for the Sino-North Korean summit in both periods.

Longitudinal Intrinsic Brain Activity Changes in Cirrhotic Patients before and One Month after Liver Transplantation

Yue Cheng,Li-Xiang Huang,Li Zhang,Ming Ma,Shuang-Shuang Xie,Qian Ji,Xiao-Dong Zhang,Gao-Yan Zhang,Xue-Ning Zhang,Hong-Yan Ni,Wen Shen 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.2

Objective: To evaluate the spontaneous brain activity alterations in liver transplantation (LT) recipients using resting-state functional MRI. Materials and Methods: Twenty cirrhotic patients as transplant candidates and 25 healthy controls (HCs) were included in this study. All patients repeated the MRI study one month after LT. Amplitude of low-frequency fluctuation (ALFF) values were compared between cirrhotic patients (both pre- and post-LT) and HCs as well as between the pre- and post-LT groups. The relationship between ALFF changes and venous blood ammonia levels and neuropsychological tests were investigated using Pearson’s correlation analysis. Results: In the cirrhotic patients, decreased ALFF in the vision-related regions (left lingual gyrus and calcarine), sensorimotor-related regions (left postcentral gyrus and middle cingulate cortex), and the default-mode network (bilateral precuneus and left inferior parietal lobule) were restored, and the increased ALFF in the temporal and frontal lobe improved in the early period after LT. The ALFF decreases persisted in the right supplementary motor area, inferior parietal lobule, and calcarine. The ALFF changes in the right precuneus were negatively correlated with changes in number connection test-A scores (r = 0.507, p < 0.05). Conclusion: LT improved spontaneous brain activity and the results for associated cognition tests. However, decreased ALFF in some areas persisted, and new-onset abnormal ALFF were possible, indicating that complete cognitive function recovery may need more time.

Influence of a Novel Mold Inhibitor on Mechanical Properties and Water Repellency of Bamboo Fiber-based Composites

( Yue Qi ),( Yu-Xiang Huang ),( Hong-Xia Ma ),( Wen-Ji Yu ),( Nam-Hun Kim ),( Ya-Hui Zhang ) 한국목재공학회 2019 목재공학 Vol.47 No.3

Effects of a novel mold inhibitor specifically for bamboo, on the properties of composite products have been confirmed in this study. The mechanical and dimensional stability properties of bamboo fiber-based composites (BFBCs) from different bamboo species were also investigated. The results showed that Burmanica Gamble possessed the highest values of modulus of elasticity (MOE) of 33.2 GPa, modulus of rupture (MOR) of 286.9 MPa, compressive strength of 182.6 MPa and shear strength of 24.0 MPa. By contrast, Phyllostochys heterocycla among all of species showed the lowest MOE of 16.3 GPa, MOR of 170.3 MPa and compressive strength of 128.9 MPa were the lowest among all of species. Moreover, there is a remarkable variation in the swelling and water absorption between the samples with 4 h and 28 h water immersion treatment, especially Phyllostachys iridenscens. Overall, the results suggested that TCIT (Tebuconazole and 3(2H)-isothiazolone) had no significant effect on the mechanical properties compared with the control condition, and it would be utilized as an antimould of BFBCs manufacturing.