A Pattern Dictionary Method for Anomaly Detection

In this paper, we propose a compression-based anomaly detection method for time series and sequence data using a pattern dictionary. The proposed method is capable of learning complex patterns in a training data sequence, using these learned patterns to detect potentially anomalous patterns in a test data sequence. The proposed pattern dictionary method uses a measure of complexity of the test sequence as an anomaly score that can be used to perform stand-alone anomaly detection. We also show that when combined with a universal source coder, the proposed pattern dictionary yields a powerful atypicality detector that is equally applicable to anomaly detection. The pattern dictionary-based atypicality detector uses an anomaly score defined as the difference between the complexity of the test sequence data encoded by the trained pattern dictionary (typical) encoder and the universal (atypical) encoder, respectively. We consider two complexity measures: the number of parsed phrases in the sequence, and the length of the encoded sequence (codelength). Specializing to a particular type of universal encoder, the Tree-Structured Lempel–Ziv (LZ78), we obtain a novel non-asymptotic upper bound, in terms of the Lambert W function, on the number of distinct phrases resulting from the LZ78 parser. This non-asymptotic bound determines the range of anomaly score. As a concrete application, we illustrate the pattern dictionary framework for constructing a baseline of health against which anomalous deviations can be detected.     

软模板印刷法制备超疏水性聚苯乙烯膜

首次利用软模板印刷的方法,以微米-亚微米-纳米复合结构的PDMS为软模板,在平滑聚苯乙烯表面上成功制备了同样具有微米-亚微米-纳米复合结构的超疏水表面,该表面与水的接触角高达161.2º。软模板印刷方法可以用在其它热塑性聚合物如聚丙烯、聚甲基丙烯酸甲酯和聚碳酸酯等材料上,是一种简单有效地制备超疏水性表面的方法。     

Dip-Pen Nanolithography(DPN): from Micro/Nano-patterns to Biosensing

Dip-pen nanolithography is an emerging and attractive surface modification technique that has the capacity to directly and controllably write micro/nano-array patterns on diverse substrates. The superior throughput, resolution, and registration enable DPN an outstanding candidate for biological detection from the molecular level to the cellular level. Herein, we overview the technological evolution of DPN in terms of its advanced derivatives and DPN-enabled versatile sensing patterns featuring multiple compositions and structures for biosensing. Benefitting from uniform, reproducible, and large-area array patterns, DPN-based biosensors have shown high sensitivity, excellent selectivity, and fast response in target analyte detection and specific cellular recognition. We anticipate that DPN-based technologies could offer great potential opportunities to fabricate multiplexed, programmable, and commercial array-based sensing biochips.     

Application of HPLC Fingerprint Combined with Chemical Pattern Recognition and Multi-Component Determination in Quality Evaluation of Echinacea purpurea (L.) Moench

Echinacea purpurea (EP) is a common medicinal material for extracting anti-RSV components. However, up to now, there has been no effective and simple method to comprehensively reflect the quality of EP. In our current study, the quality of Echinacea purpurea (L.) Moench samples from six different cultivation locations in China was evaluated by establishing a high-performance liquid chromatography (HPLC) fingerprint, combining chemical pattern recognition and multi-component determination. In this study, the chemical fingerprints of 15 common peaks were obtained using the similarity evaluation system of the chromatographic fingerprints of traditional Chinese medicine (2012A Edition). Among the 15 components, three phenolic acids (caftaric acid, chlorogenic acid and cichoric acid) were identified and determined. The similarity of fingerprints of 16 batches of Echinacea purpurea (L.) Moench samples ranged from 0.905 to 0.998. The similarity between fingerprints of five batches of commercially available Echinacea pupurea (L.) Moench and the standard fingerprint ”R” ranged from 0.980 to 0.997, which proved the successful establishment of the fingerprint. PCA and HCA were performed with the relative peak areas of 15 common peaks (peak 3 as the reference peak) as variables. Anhui and Shaanxi can be successfully distinguished from the other four cultivation areas. In addition, the index components of caftaric acid, chlorogenic acid and cichoric acid were in the range of 1.77–8.60 mg/g, 0.02–0.20 mg/g and 2.27–15.87 mg/g. The results of multi-component index content determination show that the contents of the Shandong cultivation area were higher, followed by Gansu, Henan and Hebei, and the lowest were Anhui and Shaanxi. The results are consistent with PCA and HCA, which proved that the quality of Echinacea purpurea (L.) Moench from different origins was different. HPLC fingerprint combined with chemical pattern recognition and multi-component content determination was a reliable, comprehensive and prospective method for evaluating the quality of Echinacea purpurea (L.) Moench. This method provides a scientific basis for the quality control and evaluation of Echinacea purpurea (L.) Moench.     

Unusual case of desmotropy. Combined spectroscopy (1H-14N NQDR) and quantum chemistry (periodic hybrid DFT/QTAIM and Hirshfeld surface-based) study of solid dacarbazine (anti-neoplastic)

Antineoplastic chemo-therapeutic drug 5-(3,3-dimethyl-1-triazenyl)imidazole-4-carboxamide (Dacarbazine, DTIC), has been studied experimentally in solid state by ¹H-¹⁴N NQDR double resonance at 295 K and theoretically by the Density Functional Theory (DFT)/Quantum Theory of Atoms in Molecules (QTAIM) and Hirshfeld surfaces analysis. Only one set of eighteen resonance frequencies was found in the experiment. This indicates the presence of six inequivalent nitrogen sites: –N(CH₃), –NH₂, –NH- and three –N= (of which one is a ring, two are from triazene) in the DTIC molecule. This contradicts the X-ray data which revealed the multiplication of nitrogen sites due to unusual desmotropism. The averaging of NQR frequencies caused by the fast in NQR time-scale exchange of protons in a double-well potential combined with the oscillations of twisted supramolecular synthons was proposed as a potential mechanism responsible for this apparent contradiction. An effective improvement in the quality of the spectrum reproduction was achieved when the calculations were performed assuming the periodic boundary conditions, BLYP functional, the DNP basis set and taking the 3×3×3 k-point separation. The ordering of the nitrogen sites according to the increasing quadrupole coupling constant (QCC): N(3)<N(2)<N(6)<N(1)<N(4)<N(5) reflects the metabolic pathway of DTIC. Two sites N(5) and N(4) with the highest QCC are responsible for the first step – conversion to MTIC (5-[3-methyl-triazen-1-yl]-imidazole-4-carboxamide) required for effective processes of binding dacarbazine to DNA (demethylation of N(5)), and the second step – fast conversion of MTIC to 5-amino-1H-imidazole-4-carboxamide (AIC; remove –N(4)–N(5)HCH₃). N(5) does not participate in any, while N(4) participates in weak C(2)H⋯N(4) interaction which can be readily broken. The four remaining nitrogen atoms N(1), N(2), N(3) and N(6) participate in strong intermolecular N(1)H⋯N(2) and intramolecular N(3)–H⋯N(6) bonds, which stiffen the crystalline structure.     

Conformal array realizations of the near and far fields of a complex point source

The complex point source radiates an unusual field without sidelobes in both the near and far zones. The field on a sphere in the near zone closely resembles the far-field pattern. These properties make the complex point-source field desirable in numerous applications in electromagnetics and acoustics. The complex point-source field will be generated using non-resonant arrays with properties that can be realized in the laboratory. Both standard and weighted least-squares techniques determine the array excitation coefficients. The number of array elements required to achieve a certain accuracy of the radiated field can be dramatically reduced if a conformal array structure is employed with the array elements mounted on an impenetrable object. Only the part of the impenetrable object that faces in the beam direction need to be populated with array elements. Numerical examples with array elements consisting of real point sources mounted on a Dirichlet sphere illustrate these findings.     

ZERNIKE矩的旋转不变性及对旋转角度的估计

Ｚｅｒｎｉｋｅ矩所用的变换核是一组正交变换核，并且矩的模在空间上是旋转不变的．本文指出了Ｚｅｒｎｉｋｅ矩的相位包含了所有有关目标在空间取向的信息．为了提取这一重要信息，提出利用大于给定门限的多个矩的统计估计方法．计算机模拟结果，表明了这种方法的有效性．     

用连续型分布拟合马尾松毛虫种群空间分布型

本文用连续型分布拟合马尾松毛虫越冬代幼虫的空间分布型。结果表明，在高虫口密度情况下，幼虫服从Ｗｅｉｂｕｌｌ分布或指数分布。     

Pinning and long-time-scale behavior in traveling-wave convection

We study nonlinear traveling-wave (TW) and stationary states of convection in experiments in ethanol-water mixtures. While the TW phase velocity as a function of Rayleigh number has been recently shown to be in agreement with the predictions of theory and numerical calculations, we find that this velocity is temporally modulated at frequencies corresponding to the travel time of a single convection roll and of a roll pair past a point stationary in the convection cell. This modulation could be due to the pinning of the convection pattern by experimental inhomogeneities. For large Rayleigh numbers where stationary overturning convection is expected, we sometimes observe extremely slow unidirectional TW states. For larger Rayleigh numbers, this slow TW state starts and stops intermittently on a characteristic time scale of several days. The possible origin of these phenomena and their potential utility are discussed.     

实时光电混合联合变换相关器单元的实验研究

本文根据联合变换相关的原理，提出了一种实时光电混合联合变换相关器，它采用一个液晶光阀作为输入器件，用另一个液晶光阀记录和显示联合功率谱，所给出的实验结果证实了该系统设计及性能分析的正确性。