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A practical position-based visual servo design and implementation for automated fault insertion test
(2014-01-01)
Banlue, Tassanai
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Sooraksa, Pitikhate
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Noppanakeepong, Suthichai
This paper presents the design and implementation of a practical visual servo. The visual servo has been designed for pose correction of an end-effector that is placed wrongly away from the test point on a printed circuit board (PCB). It is widely acknowledged that the error could be attributed to the connecting joints of robot arms, angular errors, geometric model, and/or camera projection model. In the automated fault insertion test (AFIT), the typical difficulty encountered by a robot is to servo and place the probe tip accurately on the targeted test point, i.e., the conductive pad on the PCB. Conventionally, touch and sense with a probe tip has been utilized. Upon detection of a failure, the visual servo is triggered and the robot literally looks through a camera and re-attempts with the use of visual information from the camera. Currently, no clearly defined specifications in carrying out feature extraction exist and thereby the test point detection as it is not cost-effective to designate part of PCB footprint as the test point separately from the main design to accommodate visual sensing. As a result, various kinds of test points have been implanted into PCB industrial design. This research work requires building of a custom knowledge base of the test point features to support image recognition. Furthermore, the operational factors in industrial manufacturing, e.g., head structure maintenance, the replacement of end-effectors and the changes of projection parameters caused by hardware adjustment, impact the accuracy of the probe placement. These factors cause the original geometric model to shift from the original configuration and thus errors. This research paper proposes the practical design of a closed-looped visual servo to address the issues of precision error, image feature extraction, and manufacturing factors. Besides, the paper details the findings from the design phase to the implementation phase. © 2014 Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg.
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The variation of critical frequency of E layer over Chumphon, Thailand
(2013-12-09)
Wongcharoen, Poramintra
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Kenpankho, Prasert
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Sepsirisuk, Kasemsuk
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Supnithi, Pornchai
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Noppanakeepong, Suthichai
In this research paper presents the observed critical frequency of E layer (foE) over Chumphon, Thailand which is located at nearly the magnetic equator (lat. 10.72° long. 99.37° dip. 3°) during September 2004 to August 2005. The foE is one of essential parameters in the International Reference Ionsphere (IRI) model. We investigate the variation of the observed foE by comparing to the Sun spot number, ionospheric index, and 10.7 cm. flux. Due to essentially of accurate IRI model can be used to applied in communication such as it may be implied tendency of phenomena in E layer effect on high frequency communication over Chumphon, Thailand. © 2013 IEEE.
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The analysis of IRBUS channel allocation for decrease four-wave mixing in DWDM system
(2013-09-18)
Jumpates, Ashira
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Srinuan, Chollatee
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Noppanakeepong, Suthichai
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Rachnarong, Vissavavit
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Injoungjirakit, Nainapas
This paper presents a new model of optical channel allocation named "IRBUS" for improving the operation of a DWDM light source multiplexing by not have to use an optical filter in the DWDM de-multiplexer device. By our method can reduce transmission loss in case of the number of channels are plentiful and each of the channels is nearby that be found in Dense Wavelength Division Multiplexing (DWDM) Systems. The transmission loss is called "Four-Wave Mixing (FWM)" caused by the nonlinearity of the optical fiber signal. The results of numerical computation shown that the IRBUS model can decrease average FWM efficiency from -12.03dBm to -28.27dBm indicated that the remains FWM value are less than other methods and can also reduce the BER probabilities from - 5dBm to -19.75 dBm. © 2013 SPIE.
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The analysis of paired unequally spaced reapeated alternate unequally spaced allocation channels for FDM lightwave system
(2011-12-01)
Jumpates, Ashira
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Rachnarong, Vissavavit
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Noppanakeepong, Suthichai
This paper proposes the new technique to improve the conventional techniques in the channel allocations, in order to reduce transmission loss, in case of there are a large number of channel and each of channel is nearby. We have found this case in Dense Wavelength Division Multiplexing (DWDM) that is the cause of transmission loss called Four-Wave Mixing due to the fiber nonlinear. The channel allocations that used to resolve this problem are Equally Spaced (ES), Unequally Spaced (US), Repeated Alternate US (RAUS). This paper present the new technique to arrange the channel allocation in called paired URAUS to avoid the four-wave mixing. From the simulation results, the new proposed technique has lower the effect of Four-Wave Mixing than the conventional techniques and decrease bit error probabilities and bandwidth, containing higher channels, in DWDM transmission systems.
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Electrical equivalent circuit model and impedance of Euglena sanguinea stimulated by multi-level electromagnetic fields
(2010-10-11)
Packamwongsang, Komphet
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Noppanakeepong, Suthichai
This research studied the characteristic of electrical properties of E. sanguinea by evaluation of complex impedance and complex permittivity. Apply Cole-Cole plot technique to explain the behavior of RC impedance form simulation and measurement. The objective of this study was to build up a new electrical equivalent circuit model from RC circuit model of E. sanguinea with MLEMF. The results revealed that there were a correlation between impedance from measurement and simulation with correlation value equal to 0.83 at 95% confidence interval. The RC impedance of E. sanguinea of each chemical component, i.e., protein, chlorophyll, carbohydrate, lipid and phosphorus was behavioral in semicircle varied to frequency which give the correlation with complex permittivity. The model can be used for design of water supply system by MLEMF for treating algae bloom water. This is an innovative electric simulation applicable to the electric engineering and other related fields of study. © 2010 IEEE.
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Adaptive OFDM modulation techniques over fading channel for wireless communication systems with an 80 MHz bandwidth
(2010-05-05)
Lakanchanh, Donekeo
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Noppanakeepong, Suthichai
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Yoshizawa, Shingo
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Miyanaga, Yoshikazu
The orthogonal frequency division multiplexing (OFDM) is one of the promising technologies to improve the spectral efficiency, enhance system capacity and mitigate inter-symbol interference in the wireless communication system. In this paper, we aim at the study on adaptive modulation and coding technologies for wireless system over frequency selective fading channel. This adaptive allocation algorithm assigns the sub-carriers. We are applied adaptive modulation technique to each sub-carrier to keep required BER and PER performance. The system chooses modulation among BPSK, QPSK, 16QAM and 64QAM which the estimated SNR of the sub-carrier inhabits. Adaptive modulation can improve communication performance under small SNR. The computer simulation result shows the BER, PER and Throughput performance can be improved under 30 dB of SNR region. ©2010 IEEE.
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Histogram compensation to improve blind modulation detection in adaptive OFDM
(2009-12-01)
Lakanchanh, Donekeo
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Yoshizawa, Shingo
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Noppanakeepong, Suthichai
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Miyanaga, Yoshikazu
This paper proposes a blind modulation detection technique for adaptive orthogonal frequency division multiplexing (Adaptive OFDM) communications. Adaptive modulations are applied to improve communication performance in OFDM over complicated multi-path fading channels. This paper proposes a new method which reduces detection errors in blind modulation and improves communication throughput in adaptive OFDM systems. The new proposed is based on statistical methods using a combination of distance histogram and phase histogram methods. It can improve communication performance and increases a data rate by not sending side information about modulation modes. The proposed method has showed better blind detection performance at lower SNR regions than the previous method. ©2009 IEEE.
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GPS overlay experiment using geostationary satellite, ETS-VIII
(2009-12-01)
Nakamura, Shinichi
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Inoue, Takahiro
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Nakamura, Ryo
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Katagiri, Seiji
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Noppanakeepong, Suthichai
For Global Navigation Satellite System (GNSS) technology, the accuracy of navigation signals (time reference signal) is very important. To improve the accuracy of the navigation signals, exact time control of the satellite and highly accurate clock synchronization between satellites and ground stations are required. JAXA plans to conduct a time synchronization experiment for future global navigation satellite technology. The objective of the experiment is to confirm whether a geostationary satellite is useful for the positioning accuracy improvement if it is used as a GNSS. This clock management technology will be utilized in the quasi-zenith satellite system, which has been studied in Japan. In this symposium, the results of a experiment and the experiment outline will be reported. © 2009 SICE.
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Rainfall rate and rain attenuation model in Bangkok, Thailand
(2008-12-01)
Chankeaw, Natthapong
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Udomariyasap, Pongputhai
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Lakanchanh, Donekeo
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Noppanakeepong, Suthichai
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Leelaruji, Nipha
This paper describes the measurement of rainfall rate at King Mongkut's Institute of Technology Ladkrabang (KMITL), Bangkok, Thailand, by using satellite signal from Thaicom5. Three years measurement of rainfall rate are presented. The experimental results indicate that the measured rainfall rate are 90mm/hr in 2005, 94 mm/hr in 2006 and 102 mm/hr in 2007. Moreover, we have developed new modify prediction model of rain attenuation by ITU-R rain attenuation model. The model provides for prediction of annual and for expected year to year variations. This model applied to collecte data compared with ITU-R model. From the results of prediction model at KMITL, we found that the highest rainfall rate 102 mm/hr in 2007 cause to signal attenuate 14.34 dB. © 2008 IEEE.
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Regression models of ultra wideband ground reflection path loss based on peak power loss
(2007-12-01)
Supanakoon, Pichaya
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Pokang, Apiradee
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Promwong, Sathaporn
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Noppanakeepong, Suthichai
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Takada, Jun Ichi
In this paper, the regression models of ultra wideband (UWB) ground reflection path loss are proposed. The UWB ground reflection path loss is defined as the ratio between the maximum amplitude of the transmitted and received signal waveforms. The polarizations of transmitted signal and ground characteristics are considered. The double and triple linear regression models are derived from the closed form expression of ground reflection path loss based on peak power loss. The regression models are shown and compared with the closed form expression. From the results, the double and triple linear regression models are appropriate for conductor and dielectric grounds, respectively. Therefore, these proposed regression models are the one choice for modeling the UWB ground reflection path loss. ©2007 IEEE.

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