A privacy-preserving distributed transfer learning in activity recognition

Telecommunication Systems - Along with the widespread use of smartphones, activity recognition using embedded inertial sensors has intrigued researchers. The learning and employing activity...     

In situ response time testing of thermocouples

Response time information is important in most applications involving transient temperature measurements with thermocouples. Traditionally, the response time of a thermocouple is measured in a laboratory at a reference condition. The laboratory response time information is useful for comparative evaluation of thermocouples but may have little relationship with the response time for the sensor in service. This is because of the effects of installation and process operating conditions on response time.

A method has been developed and validated for response time testing of thermocouples as installed in an operating process. The details are reviewed in this paper. The method is referred to as the Loop Current Step Response Test. The test involves an internal heating of the thermocouple by applying an electrical current to the thermocouple extension wires. The current is then terminated and the thermocouple output is monitored as it returns to ambient temperature. This transient output is analyzed to identify the time constant of the thermocouple. A mathematical transformation is used to convert the internal transient data to the response of the thermocouple for an external temperature perturbation.     

Simulation,model‐reduction,and state estimation of a two‐component coagulation process

The issue of state estimation of an aggregation process through (1) using model reduction to obtain a tractable approximation of the governing dynamics and (2) designing a fast moving‐horizon estimator for the reduced‐order model is addressed. The method of moments is first used to reduce the governing integro‐differential equation down to a nonlinear ordinary differential equation. This reduced‐order model is then simulated for both batch and continuous processes and the results are shown to agree with constant Number Monte Carlo simulation results of the original model. Next, the states of the reduced order model are estimated in a moving horizon estimation approach. For this purpose, Carleman linearization is first employed and the nonlinear system is represented in a bilinear form. This representation lessens the computation burden of the estimation problem by allowing for analytical solution of the state variables as well as sensitivities with respect to decision variables. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1557–1567, 2016     

Generation of all possible trees of a graph in independent groups

A special graph, the PS graph, is introduced and an algorithm is developed to generate all trees of such graphs. It is proved that for any given graph, $\text{G}$ there exists certain number of PS graphs, obtained from $\text{G}$, such that the collection of all trees of all such PS graph span all trees of $\text{G}$ with no duplication. In addition to a number of properties of PS graphs indicated, the procedure seems very useful for topological analysis and design of networks, or any other types of systems that can be represented by a linear graph.     

Large Eddy Simulation of Turbulent Heat Transfer in a Channel With a Square Cylinder

Three-dimensional turbulent channel flow and heat transfer in the presence of a square cylinder were investigated numerically for a Reynolds number of 3000. Turbulent flow was simulated using large eddy simulation in which the eddy viscosity was evaluated by a subgrid-scale model of structure function and selective structure function. The attached wall boundary layer of the channel starts to separate if an insulated cylinder is placed in the channel, and a subsequent recirculation zone appears downstream of the cylinder. Nusselt number distribution along the floor of the channel showed an increase in the downstream part of the cylinder with a relative maximum slightly downstream of the reattachment point. The position of the cylinder in cross-stream direction affects the heat transfer from the channel wall. This quantity increases with decreasing the distance between the cylinder and the channel wall. A correlation was developed for the mean total Nusselt number over the floor of the channel with the position of the cylinder in the channel.     

Preparation and photo-catalytic activity of nano-TiO2–ZSM-5 composite

Nano-anatase (TiO₂) has been synthesized on ZSM-5 zeolite by the hydrothermal method. The produced composite was characterized using X-ray diffraction, FT-IR spectroscopy and Electronic Microscopic measurements, SEM and TEM. Synthesis of nano-TiO₂ on the surface of zeolite causes high dispersion of particles over the zeolite framework and results in a higher rate of degradation of Brown-NG (an azo-dye) under UV irradiation as compared with TiO₂ (P25). Degradation of the dye was measured by an UV–vis spectrophotometer.     

Pressure transmitter accuracy

This paper discusses the key causes of calibration drift in pressure transmitters and procedures for calibrating pressure transmitters to ensure their accuracy. Calibrating pressure transmitters involves adjusting the potentiometers in the sensor that controls the zero (lowest pressure at which a transmitter is calibrated) and span (the range of pressure the transmitter is to indicate) of the transmitter. The initial or bench calibration of pressure transmitters involves using a constant pressure source such as a deadweight tester. Once the transmitters are installed, temperature, pressure, humidity, vibration, maintenance activities, and normal aging can degrade their accuracy. Transmitter accuracy can also be degraded by transmitter sensing lines, when the water in a sensing line reference leg boils off, when non-condensable gases in the reference leg dissolve, and when voids, blockages, freezing, or leakage occur in sensing lines. On-line calibration techniques enable plants to avoid these accuracy problems by monitoring the output of an individual transmitter.     

A fuzzy hybrid group decision support system approach for the supplier evaluation process

The quality and delivery performance of a typical company depends largely on the capability of its suppliers. It is therefore important for a company to evaluate the performance of its existing suppliers. However, the problem of supplier evaluation is rather complex when a group of decision makers responsible for these suppliers are geographically dispersed. Evaluating decisions requiring the elicitation of vague and imprecise linguistic information expressed in fuzzy terms. For this purpose, a hybrid fuzzy group decision-making approach for supplier evaluation is proposed, integrating the fuzzy analytic hierarchy process (F-AHP) and the fuzzy preference-ranking-organization-method-for-enrichment-of-evaluation (PROMETHEE) group decision support system (F-PROMETHEE GDSS) method. F-AHP is used to determine the weight of multiple criteria while F-PROMETHEE GDSS is applied for the final ranking of suppliers from a group decision viewpoint. The approach advances the supplier evaluation context in two aspects. First, it treats each decision maker uniquely in terms of the preference function and threshold levels. Second, it provides rapid communication between teams through video conferencing. The hybrid approach is used to evaluate the suppliers of a dairy company.     

Response time of platinum resistance thermometers in flowing gases

The determination of the time of response of industrial temperature sensors both during service and in various environments is of importance. Recent effort has been directed at this problem solution. The present paper is concerned with the determination of the response time using available procedures recently developed. A rig was constructed to test the procedures. The results appear to provide confidence in the use of these procedures.     

Condensed table of Huffman coding, a new approach to efficient decoding

This letter introduces a new technique for designing and decoding Huffman codes. The key idea is to define a condensed Huffman table (CHT) that is smaller than the ordinary Huffman table and which leads to fast decoding. For example, the new approach has been shown to reduce the memory consumption by a factor of eight, compared with the single-side grown Huffman table.