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Recently, the use of speech processing in a time–frequency domain that handles the phase spectrum in addition to the amplitude one has been increasing because many studies have revealed the importance of phase. Inspired by this motivation, this paper presents a new speech signal phase processing. The contributions of this paper include the following two points: a detailed analysis of a speech signal by considering a novel phase feature, a derivative of instantaneous frequency (DIF), and demonstrating a new phase-based voice activity detection (VAD) algorithm as one of the DIF’s applications. These contributions develop on our previous work that briefly introduced the DIF into VAD. In the analysis part, we investigate the DIF from the theoretical aspect and research the statistical distribution of the DIF of speech signals under various conditions. We also propose a new phase-based VAD algorithm via the statistical likelihood ratio, and use the DIF as an auxiliary feature to improve a conventional amplitude-based VAD method. The experimental results confirm the efficacy of the phase feature in the VAD application and the possibility of combining the phase and amplitude for better performance.

Single Point Incremental Forming (SPIF) has become popular for metal sheet forming technology in industry in many advanced countries. In the recent decade, there were lots of related studies that have concentrated on this new technology by Finite Element Method as well as by empirical practice. There have had very rare studies by pure analytical theory and almost all these researches were based on the formula of ISEKI. However, we consider that this formula does not reflect yet the mechanics of destruction of the sheet work piece as well as the behavior of the sheet in reality. The main aim of this paper is to examine ISEKI’s formula and to suggest a new analytical computation of three elements of stresses at any random point on the sheet work piece. The suggested formula is carefully verified by the results of Finite Element Method simulation.

Roller mechanism and conveyor are important components in sulfur granulation system. This paper presents the method to design roller mechanism to apply two goals: create a continuous pressure for a regular granulation on steel conveyor. There are also granulation mechanism and maintain temperature not to stuck and solidify of sulfur in the supplying pile. Moreover, this paper shows the solution to design steel conveyor and filtering system including with temperature sensor which ensure the decreasing of temperature over the length of steel bell. This will help the granulation of sulfur with the right size and shape.

This article presents a method to identify good and bad grain and then they will be classified and processed. The algorithm mentioned here will determine the good and bad grain at high speed frame (18500 frames/s), and determine the speed of rice moving. The identification of better or worse than the threshold used in the algorithm are combination of light wavelengths and identify appropriate length of grain. This paper describes the experimental results: the influence of the light wavelength, the effect of image-capturing speed, identity technique and threshold filtering.

This article presents an experimental study examining the effects of technologicalparameters to the ISF process on PVC material such as : tool diameter d, tool step depth z, feed rate fand forming temperature T, thereby the determining the limiting value of angular distortion αmax.

rd , 2012) ABSTRACTS: Market demand is always changing over time especially for plastic products. Therefore it is necessary to create sample models in the meaning of single or small-batch production which is expected with short processing time, lower cost and operating simply but also meet the technical requirement. This paper presents a research of applying ISF process on PVC plastic sheet to manufacturing sample models and small-batch products. There is also a comparison of economic efficiency between ISF technology and traditional plastic forming methods. Keyword: Appling ISF technology, ISF process, manufacturing PVC civil products.

This paper presents the design of a machine using for incremental sheet forming (ISF) technology. Mechanical design has differences compared with conventional CNC machine which has enough rigidity to match the high value of axial force when processing by ISF technology. The machine is manufactured successfully and operates stably when forming steel sheet of 210mm square and thickness of 1.5mm. It shows that the control and mechanical design presented shows appropriate and capable of manufacturing a machine with larger machining size to use for the actual sheet products in industries.

st , 2011) ABSTRACT: The paper presents an application the research results previously done by group on the influence of technological parameters to the deformation angle and finish surface quality in order to choose technology parameters for the incremental sheet forming (ISF) process to produce products for the purpose of rapid prototyping or single-batch production, including all steps from design and process 3D CAD model, calculate and select the technological parameters, setting up manufacturing and the stage of post-processing. The samples formed successfully showed high applicability of this technology to practical work, the complex products with the real size can be produced in industries: automotive, motorcycle, civil...

Single Point Incremental Forming - SPIF is the recent manufacturing process of metal sheet forming by drafting a non-cutting edge sphere-tip tool on a clamped metal sheet. The formability of metal sheet in SPIF is considered by the forming angle (ψ)- the maximum draft angle so that the material is not torn. The experimental research on A1050-H14 aluminum sheet on Bridge Port VMC500-16 CNC milling machine in C1 workshop of the HCMUT in order to find out the regression equations to predict the maximum forming angle in the relation with four most important technology parameters in SPIF: size of the step down z, forming feed vxy, spindle speed n, forming tool diameter d.

Programming is a crucial skill which is required to be mastered for students on all disciplines of the Computer Science field. For novice students, they always desire explanation and help for all errors encountered in their own solutions. With the recent advancement of Internet technologies, online tutoring systems are increasingly considered. Various systems and applications have been introduced for teaching programming. In this paper, we introduce a tutoring system known as iiOSProTrain (interactive intelligent Online System for Programming Training) for teaching students programming. In iiOSProTrain, we employ two popular formal methods, which are theorem proving and model checking, for verifying students' works and giving them detailed feedback. The usage of formal methods renders our system the following advantages, as compared to similar systems. First, iiOSProTrain can give an absolute confirmation on the correctness of the submitted programs. More importantly, iiOSProTrain adopts the concept of structured error-flow to give students traceable feedbacks on their mistakes, thus allowing them to track and correct the logic errors in a flexible and convenient manner. Currently, iiOSProTrain is deployed at Faculty of Computer Science and Engineering, Ho Chi Minh University of Technology, Vietnam for teaching first year students on programming methodologies.