Manas Sangworasil

Finite-Element Analysis and In Vitro Experiments of Placement Configurations Using Triple Antennas in Microwave Hepatic Ablation

This study presents analyses of triple-antenna configurations and designs for microwave (MW) hepatic ablation using 3-D finite-element (FE) analyses verified by in vitro experiments. Treatment of hepatic cancer often requires removal or destruction of large volume lesions. Using multiple antennas offers a potential solution for creating ablation zones with larger dimensions, as well as varied geometrical shapes. We performed both 3-D FE analyses and in vitro experiments using three identical open-tip MW antennas simultaneously, placing them in three types of configurations-ldquolinear array,rdquo ldquotriangular,rdquo and ldquoT-shapedrdquo arrangements. We compared coagulation volumes created, as well as temperature distribution characteristics, from the three-antenna arrangements after power delivery of 50 W for 60 s. We also performed additional tests using nonidentical antennas (open tip, slot, and slot with insulating jacket) for the three configurations. The results illustrate that arranging antennas in the ldquoT-shapedrdquo pattern destroyed more unwanted tissues than those found when using ldquolinear arrayrdquo and ldquotriangularrdquo arrangements, with maximum coagulation width and depth of 46 and 81 mm, respectively, and coagulation volume of 30.7 cm3 . In addition, using nonidentical triple antennas caused variations in coagulation zone characteristics, and thus, the technique could be applied to treatment situations where nonsymmetric coagulation zones are required.

Edge Detection of the Optic Disc in Retinal Images Based on Identification of a Round Shape

This paper presents a novel method for identification of the position of the optic disc in retinal images. The method is based on the preliminary detection of the main edge detection of retinal image. The segmentation optic disc is estimated as a circular area. We searched for areas of optic disc using Hough transform which detected several straight lines and approximated them as a circular line. The position of optic disc was identified as the center of the circle. An evaluation of the proposed procedure was performed using a set of 40 images from the DRIVE database, containing images from both healthy (33) and diseased (7) subjects. The optic disc position was correctly identified in 39 out of 40 images and the efficiency was 97.5 percent. The results illustrate that the proposed method can be used for pathological analysis of retinal images.

8-Electrode Data Collection System For Electrical Capacitance Tomography

An 8-electrode data collection system for electrical capacitance tomography is presented. The system mainly consists of a signal generator, 8times2 multiplexer, detector, amplifier, band-pass filter, rms-to-dc converter, A/D converter circuit and control computer. Experimental results with a circular sensor show that the proposed system is able to collect data with satisfactory sensitivities, linearity, resolution and also being insensitive to noise. Reconstructed images from collected data are shown

High-sensitivity humidity sensor utilizing PEDOT/PSS printed quartz crystal microbalance

In this work, quartz crystal microbalance humidity sensor was fabricated by inkjet printing technique. Poly (3, 4-ethylenedioxythiophene)/poly-styrene-sulfonic acid (PEDOT/PSS), one of the most widely used polymer composites, was printed on QCM electrode as sensing layer using Dimatrix material inkjet printer. The main advantage of this coating method is its high precision of solution coating with accurately controlled volume and area. The printed layer was varied from 1 to 20 layers. With 20 PEDOT/PSS printed layers, the humidity sensitivity is found increased by more than three orders of magnitude compared to uncoated QCM. In addition, the PEDOT/PSS coated QCM exhibits fast humidity detection with short response and recovery times. Thus, the PEDOT/PSS printed on the QCM electrode is an effective way to improve humidity-sensing characteristic of QCM.

A design of embedded dmx512 controller using FPGA and XILKernel

A design of the various control devices with a DMX512 Protocol is widely used in many areas, such as decorative lighting for both inside and outside of the building, or stage lighting and equipment control, such as spot light, smoke machine, strobe light, moving light. This article presents the creation of Embedded DMX512 Controller using FPGA with Real Time Operating System (RTOS). This creation enables us to build multiple channels of DMX Controller within a single device and to control DMX Controller through the TCP/IP. Thus we can control or update the data through the internet.

2D Ultrasonic Reflection Tomography by Linear Array Transducer and Wave Reflector

In general, it was known that when the series of an ultrasonic broadband pulse travel through living organ or soft tissue, their reflected projection data can be used to reconstruct a novel tomographic image. Whereas, a data obtain from an ultrasonic tomography in transmission mode is not able to be used for reconstruction a characteristic image of soft tissue which naturally shadowed by a bone or hard tissue. An ultrasonic tomography in reflection mode is realized to be a solution for this problem. However the implementation to identify the projection by using an integrated attenuation coefficient of tissue from the pulsed wave ray path in reflection mode is still more complicated. In this paper, we propose a simulation in 2D of a reflection-mode ultrasonic tomographic system by using the linear array transducer and also a frequency centroid shift method to calculate the projection data. The imaging setup system was enhanced by wave reflecting plate in order to increase an echo wave path. The ultrasound wave paths of our simulation system were intend to focus on the fan beam trajectory which is rather close to a real propagation of the ultrasound wave travelling through soft tissue and ART was used finally as an image reconstruction algorithm. The obtained output shows that our system is more practical and possible toward for using in a clinical trial.

High current low frequency eddy current imaging system

Eddy current technique plays an important role in non destructive test. Based on the principal of electromagnetism. We introduce, in this paper our new eddy current imaging system for flaw detection in aluminium plate. The propose system using high current and low frequency with single coil. Results of some preliminary experiments have been shown satisfy sensitivities, resolution and stability of the proposed system.

Multiresolution Image Alignment based on Discrete Wavelet Transform

We introduce a multi-resolution image registration based on using discrete wavelet transform. We first extract contour from both images that we want to align. The extracted contours are then fitted with B-spline curve representation to synthesize the new contours with equal number of point. The area parameter is used in the B-spline fitting to make the new generated curve immune to affine transformation. Before representing the B-spline contour with discrete wavelet transform, the problem of starting point of the contour needs to be handle. This can be done by computing the maximum curvature. The maximum curvature is selected as the starting point. Once the starting points on the contour have been established, the discrete wavelet transform is then recursively represented the contours until only a few points are remained. Due to the affine-invariant properties of discrete wavelet transform, these points can be used as landmark points for registering the transformed contour with the original contour. The experiments have shown that the purposed methods are robust and promising even in the presence of noise.

An investigation of robustness in independent component analysis EMG

We developed a multi-channel electromyogram acquisition system using PSOC microcontroller to acquire multi-channel EMG signals. The two channel surface electrodes were used to measure and record EMG signals on forearm muscles. These two channels of EMG signals were performed a blind signal separation by using an independent component analysis (ICA) technique. The well known ICA algorithm called FASTICA is a useful method to separate two or more linear combination of source signals into statistically independent components. The results show that the ICA applied EMG is more robust than the without ICA applied EMG since the statistic variation is improved.

Fabrication of QCM sensor array and PDMS micro chamber for biosensor applications

In this work, an array of quartz crystal microbalance (QCM) sensors is fabricated on a single quartz crystal substrate and attached with poly(dimethylsiloxane) (PDMS) micro chamber for using in flow-injection system. The Cr/Au electrode array is deposited on both side of quartz substrate by sputtering through electroplated microshadow mask. PDMS micro chamber was fabricated by mold casting technique with SU-8 mold. Fabricated PDMS micro chamber and QCM sensor array were attached together for using in flow-injection system. In our experiment, the QCM electrodes were coated with the carboxylic poly(vinyl chloride) (PVC-COOH) and then the carboxylic group was activated with carbodiimide hydrochloride (EDC) and N-hydroxylsuccinimide (NHS) for protein binding. The scanning electron micrograph shown the trapped protein on the modified sensing layer, it confirmed that our QCM sensor and PDMS micro chamber can be used as QCM biosensor array. This new QCM sensor array provide possibility of multiple detection in small amount of sample within a single quartz crystal substrate that avoid the error signal from the different properties of each sensor in an array.