Pruning Redundant Alarm Correlation Patterns

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Pilot Based Channel Estimation in IEEE 802 16a OFDM System

1　Introdution　IEEE 802 16[1] is a specification for fixed broadbandwireless Metropolitan Access Networks (MAN). The stan dard is expected to bring low cost and more bandwidth prod ucts for broadband wireless access in the next years. Thisstandard specifies the physical (PHY) and Medium AccessControl layer (MAC) of the air interface of interoperablepoint to multipoint and optional Mesh topology broadbandwireless access system. The specification enables access todata, …     

The Research of ST-OFDM in Physical Layer of IEEE 802.16a

This paper briefly introduces one of the three physical layer implementations of IEEE 802.16a~[1],WirelessMAN-OFDM PHY.Based on the implementation,the combination of Orthogonal Frequency Division Multiplexing(OFDM)and Space-Time Coding(STC)which is briefly called ST-OFDM in IEEE 802.16a,is investigated under thechannel provided in Ref.[2].Especially,this paper is focused on the influence of the optimal decision threshold on the sys-tern Bit-Error-Rate(BER)performance based on unequal probabilities of sources.The simulations show that when Signal-Noise-Ratio(SNR)is low the optimal decision threshold is obviously superior to the usual one;when SNR is high to someextent,such as 10 dB for 4QAM and 16 dB for 16QAM,we can use the usual decision threshold instead of the optimal     

PREPARATION OF TEM THIN FOIL CONTAINING POWDER PARTICLE BY ELECTRODEPOSITION METHOD

A practical technique to prepare transmission electron microscopy （TEM） thin foil containing powder particle was described and the data for the codeposition of two type particles with copper in the electroplating were presented. By depositing the particles which were distributed in CuSO4 electrolyte on cathode together with Cu^2＋ in electrodeposition bath, composite coating with suitable thickness could be formed. The thin coating was separated from the substrate and cut into a disc with diameter of 3mm for electropolishing. When the Cu matrix was thinned during electropolishing, the particles contained in the coating plate were also thinned to meet the suitable thickness for TEM observation. Various experimental results revealed that during electrodepositing the current density, pH-value of electrolyte and stirring mode all have significant effects on the distribution of particles in composite coating and the surface quality of the composite coating. The proper parameters used during electrodepositing to prepare TEM thin foil containing powder particle were discussed.     

0.91Pb(Zn1/3Nb2/3)O3-0.09PbTiO3的析晶行为及助溶剂法生长

研究了0.91Pb(znl/3Nb2/3)O3-0.09PbTiO3(PZNT91/9,摩尔分数)在不同组分和配比熔盐中的析晶行为及其对晶体生长的影响。发现B2O3,PbF2等助溶剂不利于钙钛矿相的析出;而BaTiO3-PbO复合体系虽然能够促进钙钛矿相析出,但晶体析出量很少;只有适当比例的。PbO助溶剂比较适合于生长具有铁电性的钙钛矿相PZNT91/9单晶。助溶剂法生长的工艺参数为:溶质与PbO助溶剂的摩尔比为l:l,泡料温度1 150-1 200℃,泡料时间10 h,晶体生长时降温速度0.8-2℃/h,当温度降到900℃时停止生长,以50℃/h快速冷却至室温。所得晶体为琥珀色,最大尺寸达φ30 mm×15 mm,其压电系数和机电偶合系数分别为2000 pc/N和0.92。     

Exploration of Linked Anomalies in Sensor Data for Suspicious Behavior Detection

We present a visual analytics system to understand the operation data of a company, GAStech, from IEEE VAST Challenge 2016. The data include proximity data recording the locations and movements of employees, and heating, ventilation, and air conditioning (HVAC) data recording the environmental conditions in the building. Analyzing the data to detect the suspicious behaviors of some disgruntled employees is of special interest. Our system provides coordinated multiple views to visualize the proximity data and the HVAC data over time. Visual hints and comparisons are designed for users to identify abnormal patterns and compare them. Furthermore, the system automatically detects and correlates the anomalies in the data. We provide use cases to demonstrate the effectiveness of our system.     

硅酸镓镧结构的新型压电晶体的研究进展

新型压电晶体La3Ga5SiO14因其低声速、零温度切向和良好的高温稳定性受到关注，但是昂贵的Ga2O3原料阻碍了它的工业应用。通过离子置换可获得具有langasite结构的多种新型压电晶体。综述介绍了置换La，Ga，Si形成的新型压电晶体的最新研究进展，比较分析了不同晶体的优势及其存在的问题。在这些新晶体中，由于Sr3Ga2Ge4O14（SGG)具有熔点较低、性能较高的综合优势，它有可能成为新一代表面波器件的重要候选材料。与提拉法相比，采用增蜗密封的下降法生长SGG单晶；可以显著提高晶体产率，降低成本。     

Corrosion behavior and mechanism of the automotive hot-dip galvanized steel with alkaline mud adhesion

The corrosion behavior and mechanism of hot-dip galvanized steel and interstitial-free (IF) substrate with alkaline mud adhesion were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and linear polarization. The results show that non-uniform corrosion occurs on the galvanized steel and IF substrate during 250 h with the mud adhesion. The corrosion products on the galvanized steel are very loose and porous, which are mainly ZnO, Zn5(OH...     

建筑涂料水性化谁主沉浮

介绍建筑涂料水性化。从五十年代至今发展的必然性和存在的优势是显而易见。但其产品品种单一，质量不尽人意，其中存在一哄而上，技术实力不一等问题，而在我们涂料工业中却未能引起重视。建筑涂料水性化既为发展方向，必由我们涂料工业担当此任，为未来发展应发挥主力军作用。     

Mathematical Advancement of General Chlorine Bulk Decay Model

An accurate chlorine bulk decay model is needed to ensure that potable water meets the microbial and the chemical safeties at the treatment plant and throughout the distribution. Among the mathematical models available,the general second-order chlorine bulk decay model( GBDM) is the most fundamentally sound.Application of the GBDM,however,has been hindered by its numerous fictive parameters and lack of an analytical solution. This theoretical work removes the two obstacles. The GBDM is solved through transformation and integration. The analytical solution provides deep insights into the GBDM and facilitates the parameterization and sensitivity analysis. The background natural organic matter( NOM) is characterized with the probabilistic distribution of functional groups. It reveals that the mean of the function group distribution is correlated with the initial chlorine decay rate coefficient( κ_0). A simple formula is developed to determine κ_0 directly from the initial chlorine decay. The theoretical treatment reduces the fictive parameters to a minimum. For the common lognormal distribution,the GBDM needs only three parameters,well defined as initial chlorine demand X_0,median rate coefficient km,and heterogeneity index σ. For more complicated scenarios,composite distributions are constructed through superposition of individual distributions. A highlighted example is to predict chlorine decay in blends of different waters. With the theoretical and mathematical advancement here,the GBDM can be applied effectively to any reactive background matter in any reaction systems.