Forecasting Stock Time-Series using Data Approximation and Pattern Sequence Similarity

Time series analysis is the process of building a model using statistical techniques to represent characteristics of time series data. Processing and forecasting huge time series data is a challenging task. This paper presents Approximation and Prediction of Stock Time-series data (APST), which is a two step approach to predict the direction of change of stock price indices. First, performs data approximation by using the technique called Multilevel Segment Mean (MSM). In second phase, prediction is performed for the approximated data using Euclidian distance and Nearest-Neighbour technique. The computational cost of data approximation is O(n ni) and computational cost of prediction task is O(m |NN|). Thus, the accuracy and the time required for prediction in the proposed method is comparatively efficient than the existing Label Based Forecasting (LBF) method [1].Comment: 11 page

Low power organic field effect transistors with copper phthalocyanine as active layer

Bottom gate, top contact Organic Field Effect Transistors (OFETs) were fabricated using copper phthalocyanine (CuPc) as an active layer. The electrical properties of OFETs fabricated with CuPc annealed at different annealing temperatures and different channel length to width (L/W) ratios were studied. The transfer characteristics of the devices appear to improve with annealing temperature of CuPc and increasing L/W ratios of the devices. Upon annealing, the field effect mobility increased from 0.03 ± 0.004 cm2/V to 1.3 ± 0.02 cm2/V. Similarly, the interface state density reduced from 5.14 ± 0.39 × 1011 cm−2eV−1 for the device fabricated using as deposited CuPc, to 2.41 ± 0.05 × 1011 cm−2eV−1 for the device with CuPc annealed at 80 °C. The on/off current ratio increased from 102 for the as-deposited device, to 105 for the device with CuPc annealed at 80 °C. The dependence of the subthreshold swing on the L/W ratio was also investigated. Keywords: Organic field effect transistors, CuPc, Scanning tunneling microscope, Interface trap density, Carrier mobilit

A new theoretical technique to study the temperature variation of electrical conductivity as applied to α-quaterthiophene (α-4T) thin films

α-4T thin films of various thicknesses are prepared by thermal evaporation method. The electrical conductivity (σ) of as deposited α-4T thin films of thicknesses 50 nm, 100 nm and 200 nm have been measured using Hall measurement system (HMS). Using the measured values of conductivity and energy gap, the constant σ0 has been estimated for thin films of various thicknesses. Thus, the electrical conductivity of the thin films of 50 nm, 100 nm and 200 nm have been estimated for various temperatures (T). Ln (σ) vs. 1000/T plots for thin films of various thicknesses have been drawn. The conductivity is found to decrease with increase in thickness of the thin film, as it changes from 50 nm to 200 nm