Key Engineering Materials Vols. 480-481

Abstract: A process mining approach based on α-algorithm is proposed, which can be applied to mine duplicate tasks contained in workflow logs. In this algorithm, the duplicate tasks are marked by the heuristic rules, the workflow models containing duplicate tasks are constructed using α-algorithm from identified logs. Experimental results validate the efficiency of the algorithm.

Abstract: This paper studies the exponential stability problem of uncertain delayed systems with multiple delays and parameter uncertainty. By employing the Lyapunov-based method and some matrix inequalities techniques, new sufficient conditions of the exponential stability for uncertain delayed systems are derived. Our sufficient conditions are in a form of algebraic matrix inequalities, which can be applied easily. Finally, numerical examples are presented to illustrate the effectiveness of our results.

Abstract: A kind of minimum mean square error linear equalizer (MMSE-BLE) algorithm is presented for the solution on channel capacity of single-carrier code division multiple accesses (SC-CDMA) system, this algorithm received data symbol vector multiplied by covariance matrix by using Wiener estimator, and gets the decorrelation of multiple access interference (MAI), inter-symbol interference (ISI) and noise. MMSE-BLE algorithm calculates the channel capacity with MMSE criterion algorithm, so that it can analyze the multi-user uplink channel capacity of space-time coding SC-CDMA system under the multipath conditions effectively. The simulation results show that the number of user, path, transmitting and receiving antennas, multipath diversity gain, etc. All of them have an impact on the capacity of multi-user system, it seems that multiple antennas should be used for reception to get single-path diversity gain in frequency selective channels.

Abstract: The paper presents a new method to remove baseline drift in the brain blood stream signal based on cubic spline interpolation theory. Firstly, detect some characteristic points in the original signal, and then fit the drifting baseline based on the cubic spline interpolation technique. Finally the original signal minus the baseline is the steady signal of brain blood stream. Lots of simulation experiments and clinical tests had been done, and the baseline drift in LabVIEW software program was removed perfectly. Once the method to remove baseline drift is put in practice, its effect is good and its speed is fast, and it is easy to carry out. It has great application in brain wave monitor with embedded CPU and real time character, and it is also applied in other signal detectors.

Abstract: In this paper, the axial elongation of vertical shell and tube heat exchanger with expansion joint are studied based on thetheories of static mechanics. The axial elongations of heat exchanger’s tube side and shell side that causes by thermal expansion, internal pressure and gravity are considered individually. By comparing and analyzing a typical example, it is shown that thermal expansion is the key reason other than internal pressure and gravity to the axial elongation of tube side and shell side structure. The results show that the axial elongation induced by internal pressure and gravity except thermal expansion is only 5% of total and can be eliminated in engineering practice.

Abstract: We design and implement a kind of dynamic report model in Silverlight application which based on TelerikReporting component and the technology of dynamic linked library. This model supports multi-parameter choice and can format custom report dynamically based on decided condition. By custom filter, this model implements filtrating large amount of data by receiving multiple parameters with multiple values.

Abstract: To detect the quality of batch drilling quickly，a new approach based on Acoustic Emission signals is presented. The signals’ statistical characteristics are extracted from acoustic emission signals in Time-domain, and then the signals’ eigenvectors are constructed to reflect each drilling process. A modified incremental clustering algorithm InDBSCAN is used to cluster these eigenvectors，and the batch drilling-quality can be analysed indirectly. Calculation and analysis results show that: the conclusion of incremental cluster analysis is more reasonable by the modified incremental clustering method of InDBSCAN. The detection accuracy of the batch drilling-quality is up to 84.3% according to the manual quality inspection.

Abstract: Scanning tunneling microscopy is a precise nano measuring machine, and high precision means the influence factors of scanning tunneling microscopy is important to the measurement result. The micro vibration is an obvious interferential factor to scanning tunneling microscopy, especially the low frequency vibration. In order to avoid the influence of vibration, the vibration detection in the tunneling state and vibration compensation are key aspect and are one passive approach to improve the measurement accuracy.

Abstract: As we know, there is plenty of waste hot water produced by families’ shower or Sauna and drained directly into the environment. It causes high energy consumption and heat pollution to the environment. In order to recover the heat of shower waste water to save energy, we developed a small scale shower waste water source heat pump (SWWHP) water heater and carried out experiments on it to study its heating performance. Experiments showed that this heat pump water heater system had advantages such as quick starting, compact structure, no need of hot water tank, stable operation and energy saving, etc. It could be used to supply hot water above 40°C for shower or heating, ventilation and air conditioning (HVAC). Measured data showed that during the whole year, when the temperatures of waste water and city water were 20.1～35°C, 20.1～30°C, respectively, it could supply hot water at volumetric flow rate of 2.5～9.6L/min and temperature of 40.1～51.2°C and its heating coefficient of performance (COPh) varied in the range of 3.06～4.81. It could supply enough shower hot water in the whole year in South China and the energy saving efficiency was obvious. Analysis also showed that the COPh was closely relevant to the ratio of temperature differences of waste water and hot water, i.e., ΔTw/ΔTh. The correlation equation of COPh and ΔTw/ΔTh was obtained by method of data regression and it could be used to evaluate the performance of the SWWHP water heater system with error of ±6%.

Abstract: The factors of aliasing in the nonsubsampled Contourlet transform(NSCT) has been analyzed.The primary reason has been pointed that the à trous algorithm binary zero-interpolation brought about the width of the filter rapid increase and border distortion (that is aliasing). On that basis,a new approximate shift-invariant non-aliasing pyramidal decomposition was proposed instead of the à trous algorithm nonsubsampled pyramidal decomposition in the NSCT,So a new approximate shift-invariant non-aliasing nonsubsampled Contourlet transform(NANSCT) was constructed. Compared to the NSCT,the basis image of the NANSCT has better spatial domain regularity, frequency domain localization and decreased redundancy.The experimental results show that whether PSNR index or in visual effect, the proposed scheme outperforms the traditional Contourlet transform hard threshold denoising , Contourlet domain HMT denoising and the NSCT hard threshold denoising, and can achieve an excellent balance between suppressing noise effectively and preserving as many image details and edges as possiblet.