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ABSTRACT: Vessel segmentation is very important in an automatic screening system for fundus images. Vessels are often segmented and removed from retinal images before the other residual lesions are detected. Incomplete vessel removal usually causes a false positive in lesion detection, especially for Microaneurysms detection. Segmenting vessels in spatial image domain makes miss detection due to non illumination and noises in retinal images. Non-illumination problem can be disregarded by segmenting the vessels in spatial-frequency domain, which invariant subbands can be ignored. This paper presents a new retinal blood vessel segmentation method based on fractal dimension in spatial-frequency domain of retinal images. The fractal dimension value of each pixel is computed in order to extract the vessels from their retinal background. The performance of the proposed method is evaluated and compared with the experts' diagnosis in the STARE database.
Communications and Information Technologies (ISCIT), 2010 International Symposium on; 11/2010
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[hide abstract]
ABSTRACT: The increasing amount of wind power generation in Thailand power systems requires stability analysis considering interaction between wind-farms and transmission systems. Dynamics introduced by dispersed wind generators at the distribution level can usually be neglected. However, large wind farms have a considerable influence to power system dynamics and must definitely be considered for analyzing power system dynamics. For this purpose, a detailed dynamic model of fully enclosed squirrel cage induction generator with gearbox (full-scale power electronics converters) of a 2.3 MW wind turbine with has been implemented using the modeling environment of the simulation software DIgSILENT PowerFactory. For investigating grid compatibility aspects of this wind generator concept, a model of a 96.6 MW wind farm, with typical layout, based on 42 wind turbines of the 2.3 MW-class has been analyzed. This paper is focusing on transient stability and fault ride through capability when the grid voltage has dropped to a very low value.
Harmonics and Quality of Power (ICHQP), 2010 14th International Conference on; 10/2010
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ABSTRACT: This paper reports a capacitive pressure sensor for human activity monitoring application, which is fabricated by Au-Au diffusion bonding in ambient pressure. The optimized condition for the Au-Au bonding was investigated. A maximum bonding strength of 26.7 MPa is achieved with a bonding temperature of 400<sup>o</sup>C and bonding pressure of 5.5 MPa. By measuring the pressure-capacitance characteristics of the atmospheric pressure sensor, its sensitivity is found to be 7 fF/kPa with a good linearity in the ambient pressure range from 60 kPa to 100 kPa.
World Automation Congress (WAC), 2010; 10/2010
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ABSTRACT: In non-destructive granular material dielectric measurement, microwave cavity resonator technique which is dependent against varied size and shape of cavity is suitable. Since the transmitted microwave should equally cover around the shape, system design is needed to consider transmitted microwave equally covering all area of cavity. This paper proposes a system of microwave cylindrical cavity resonator using combination of circular and rectangular waveguides for granular material dielectric measurement. In the system, the waveguide transmitters which are circular and rectangular waveguides are set in the perpendicular position to propagate the microwave into the resonator. The microwave that is excited by these waveguides propagates to receiver port for subsequent analysis. The resonator dimension is designed for resonant at 2.45 GHz and TE111 mode which is the dominant mode of cylindrical resonator. The distribution of electric field from two combination waveguide transmitters cover to the cylindrical cavity resonator or all of the material inside the resonator can absorb the electromagnetic wave. Finally, the electromagnetic wave can propagate to the receiver port for additional analysis. The prototype has been constructed according to proposed concept, and the evaluation results are demonstrated by simulation.
SICE Annual Conference 2010, Proceedings of; 09/2010
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ABSTRACT: 1 × 8 and 1 × 16 optical packet switching (OPS) node subsystems are demonstrated. The OPS node consists of a 1 × N monolithically integrated InP optical phased-array switch, an electronic switch controller, and a label extractor/eraser that utilizes cascaded reflective fiber Bragg gratings. In-band parallel labels are employed to encode the address information. 160-Gb/s optical time-domain-multiplexed packets are dynamically switched to 8 and 16 outputs with power penalties of 0.5 and 0.7 dB, respectively.
IEEE Photonics Technology Letters 07/2010; · 2.19 Impact Factor
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ABSTRACT: This paper presents field experimental results of peak frequency efficiency of approximately 50 bps/Hz, i.e., 4.9 Gbps packet transmission in a 100-MHz channel bandwidth, using 12-by-12 MIMO-OFDM focusing on the influence of fading correlation between the transmitter and receiver antennas using vertically polarized antennas. Maximum likelihood detection (MLD)-based signal detection was employed to achieve such high frequency efficiency with the required received signal-to-noise power ratio (SNR) of less than 30 dB. From the field experimental results under non-line-of- sight conditions, we show that the required average received SNR to achieve the throughput of 4.9 Gbps is degraded by less than 0.5 dB when the receiver antenna separation is reduced from 40 cm (6.2¿) to 10 cm (1.5¿), while it is degraded by approximately 1.5 dB when the transmitter antenna separation is decreased from 70 cm (10.9¿) to 20 cm (3.1¿). Furthermore, we clarify that the required minimum antenna separations of the base station transmitter and mobile station receiver are 20 cm and 10 cm, respectively, in order to achieve the peak throughput of 4.9 Gbps at the average received SNR of less than 30 dB in a field environment.
Communications, Control and Signal Processing (ISCCSP), 2010 4th International Symposium on; 04/2010
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ABSTRACT: We demonstrate a 1 Ã 16 optical packet switch sub-system for 160 Gbps RZ-OOK and 12 Ã 10 Gbps multi-wavelength DPSK packets. We show error-free operation with maximum penalties of 0.7 dB for 160 Gbps RZ-OOK and 0.6 dB for multi-wavelength DPSK packets.
Photonics Society Winter Topicals Meeting Series (WTM), 2010 IEEE; 02/2010
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ABSTRACT: For efficient retrieval of data, design of the data structuring is important. Tree structures and hash tables are popular data structures. A hash table is a simple data structure and it can be retrieved very fast for an exact match query. But for a range query, the hashing scheme is necessary to search much more data blocks than other data structures. In this paper, in order to overcome this problem, the order-preserving linear hashing scheme is proposed. This hashing scheme is based on linear hashing which uses specific hash function enabling efficient retrieval for range queries. By comparing the proposed hashing scheme with the traditional linear hashing scheme, our scheme proves to provide better retrieval time for range queries.
Systems, Man and Cybernetics, 2009. SMC 2009. IEEE International Conference on; 11/2009
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K. Higuchi,
N. Kishimoto,
T. Mizuno,
K. Kawahara,
S. Tachikawa,
Y. Murata,
M. Tsuboi,
H. Ogawa,
S. Kimura,
H. Ujihara,
A. Meguro,
H. Tanaka,
M. Yoshihara,
S. Iikura
[show abstract]
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ABSTRACT: To achieve scientific improvements from VSOP (HALCA) to VSOP-2
(ASTRO-G), the satellite design incorporates the engineering
characteristics of a large-scale deployable antenna of offset Cassegrain
type with observation bands of 8, 22, and 43 GHz. The antenna subsystem
requires the surface accuracy of 0.4mm RMS on the main reflector named
LDR (Large-scale Deployable Reflector) of about 9m in diameter. An
off-axis paraboloid reflector is adopted to achieve this surface
accuracy for millimeter-wave observation. The main reflector is composed
of seven deployable modular antennas, and each of the modules employs a
new idea of radial-rib/hoop-cable reflector construction to stretch
metal mesh and to satisfy the required surface accuracy. The deployment
mechanism employs most of the LDR technology developed for JAXA's
ETS-VIII satellite, which was launched in December 2006, and both of the
two antennas on the ETS-VIII deployed successfully on orbit. Some
prototype models of one module have been made to investigate the surface
accuracy. In addition, the antenna will have a two-axis adjustment
mechanism for the main reflector, and a three-axis adjustment mechanism
for the sub-reflector in order to optimize the antenna gain after
deployment in orbit.
07/2009; 402:41.
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ABSTRACT: Many research works have been carried out to measure and use a driver's gaze directions to prevent traffic accidents caused by inattentive driving, neglect to confirm safe conditions, and other driver errors. A calibration process is needed to measure correct gaze directions for a gaze tracking system. However, existing calibration methods require a driver to gaze at specified points before driving. In this paper, we propose a method for automatic calibration of an in-vehicle gaze tracking system by analyzing the driver's typical gaze behavior. The proposed method uses the rear-view and the side-view mirror positions as reference points. The effectiveness of the proposed method is demonstrated by experiments on measuring gaze directions in actual road environments.
Intelligent Vehicles Symposium, 2009 IEEE; 07/2009
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ABSTRACT: The excessively long reviewing times for diagnosis of capsule endoscopy present a clinical problem. A new method, ldquoadaptive speedrdquo, which automatically controls display rates of the video capsule endoscopy images, was proposed to address the problem. In this paper, we investigate the effectiveness of this method versus a standard-view using the existing system. The main activities of examining doctors during a series of evaluations using both systems are recorded. For comparisons, logged actions are analyzed to show three criteria: 1. Diagnostic time, 2. Ability to capture abnormal regions, and 3. Operability for the examining doctors. We conclude that adaptive speed reduces examination time by ten minutes from that of the existing system, while the number of abnormalities found are similar. As well, examining doctors need less effort because of the systems efficient operability.
Robotics and Biomimetics, 2008. ROBIO 2008. IEEE International Conference on; 03/2009
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ABSTRACT: This paper proposes a VT-AMDF pitch detection algorithm which based on average magnitude difference function (AMDF). Time processing is important when implement in real time system. In order to decrease computational time and complexity of pitch detection, the VT-AMDF uses only 55% of total time intervals. The method can reduce the computational time 1.3, 1.4, 4.8 and 5.4 times, compared with original AMDF, autocorrelation function (ACF), normalized square difference function (NSDF) and YIN, respectively. The experiments evaluate on seven words in five different tones of Thai isolated word. The results show that the gross error of VT-AMDF is 3.88%, which is more than original AMDF 0.48 and YIN 0.22, but less than ACF 0.54 and NSDF 1.47.
Intelligent Signal Processing and Communication Systems, 2009. ISPACS 2009. International Symposium on; 02/2009
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ABSTRACT: Multidimensional arrays storing multidimensional data in MOLAP are usually very sparse. They also suffer from the problem that the time consumed in sequential access to array elements heavily depends on the dimension along which the elements are accessed. This problem of ldquodimension dependencyrdquo would be alleviated by dividing the whole array into the set of smaller hypercube shaped subarrays called ldquochunksrdquo. But the chunks are also sparse and should be compressed. However, further dimension dependency in accessing array elements would be caused, unless these compressed chunks are arranged judiciously in the page buffer. The difference among the dimension cardinalities could also cause dimension dependency; slice operation along a dimension of large cardinality tends to consume much time. We will alleviate these two kinds of dimension dependency by introducing the notion of an ldquoextended chunkrdquo. Extended chunks can adapt flexibly to the general situation where data densities in chunks are low and are not uniformly distributed. Employing extended chunks, we will propose some secondary storage schemes for a multidimensional array using a space-filling curve such as Z-curve. The evaluation result shows that the proposed storage schemes exhibit good performance while alleviating the dimension dependency.
Digital Information Management, 2008. ICDIM 2008. Third International Conference on; 12/2008
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ABSTRACT: A piezoelectric ultrasonic hydrophone array was fabricated using diaphragm transducer on Si substrates. A two dimensional (2-D) array of 8 times 8 elements with diaphragm transducer has been developed by XeF<sub>2</sub> etching from the topside of Si. In this paper, we describe the fabrication process of the diaphragm transducer array. A finite-element analysis (FEA) was calculated to evaluate the resonant frequency of the diaphragm transducer. The potential for this hydrophone array is discussed.
Ultrasonics Symposium, 2008. IUS 2008. IEEE; 12/2008
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ABSTRACT: This paper presents the optimum control interval for intra-cell fractional transmission power control (TPC) for a shared data channel employing frequency domain channel-dependent scheduling and adaptive modulation and coding (AMC) in the evolved UTRA uplink using single-carrier (SC)-FDMA radio access. The simulation results show that the best attenuation factor in the fractional TPC is approximately 0.6 for achieving the maximum user throughput when the maximum target received signal power, P<sub>0</sub> is -60 dBm. Then, we show that the optimum averaging interval for the desired signal level, which corresponds to a substantial control interval for the fractional TPC, is approximately 100 - 200 msec regardless of the maximum Doppler frequency up to 222 Hz and the distance at the shadowing correlation of 0.5. Throughout the simulation results, we verify that slow intra-cell fractional TPC associated with fast AMC is effective in achieving the maximum cell throughput and cell-edge user throughput.
Wireless Communication Systems. 2008. ISWCS '08. IEEE International Symposium on; 11/2008
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ABSTRACT: Tins paper presents the most appropriate transmit diversity scheme for the synchronization channel (SCH) employing the latest radio interface for the SCH structure and sequences based on system-level simulations in the evolved UTRA downlink. The transmit diversity candidates assumed in the paper are preceding vector switching (PVS), time switched transmit diversity (TSTD), cyclic delay diversity (CDD), and frequency switched transmit diversity (FSTD) based on the features of the SCH. Simulation results show that transmit diversity is effective in increasing detection probabilities of SCH timing detection in the first step and the cell ID group-specific SCH sequence in the second step of the cell search process. Moreover, we clarify that PVS is the best transmit diversity scheme for the SCH based on the reduction in the cell search time. We show that PVS achieves fast cell search in less than approximately 20 msec at the location probability of 90% regardless of the inter-site distance up to 10 km.
Vehicular Technology Conference, 2008. VTC 2008-Fall. IEEE 68th; 10/2008
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[show abstract]
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ABSTRACT: This paper presents a match of X-ray teeth films using image processing based on special features of teeth. This method will help the dental doctors to match simply a pair of teeth using the special features of the teeth films. Teethpsilas pictures are scanned and adjusted by a scanner and a computer, respectively, as well as then they are converted into binary code and decoded to the direction code (chain code). The chain code of each picture is compared with the statistical chain code. Therefore, the percentage of the same chain code is approximately 90% (i.e. matching same patterns) for the comparison of one root to one root (7 times) and two roots to two roots (7 times) while the percentage of the same chain code is reduced at relatively below 50% (i.e. matching different patterns) for comparison of one root to two roots (2 times).
SICE Annual Conference, 2008; 09/2008
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K. Kimura,
H. Ogawa,
H. Ujihara,
N. Kishimoto,
K. Kawahara,
T. Mizuno,
Y. Murata,
M.C. Natori,
H. Hirabayashi,
M. Tsuboi, K. Higuchi,
H. Saito,
M. Yoshihara,
S. Iikura
[show abstract]
[hide abstract]
ABSTRACT: Following the success of the first VLBI Space Observatory Programme (VSOP), a satellite of a next space VLBI project, ASTRO-G/VSOP-2, is being designed. Very long baseline interferometry (VLBI) is a technique to achieve very high angular resolution imaging of celestial radio sources by combining the signals from widely separated radio telescopes. Space VLBI extends the separation beyond the Earth by placing one telescope on a satellite.
Antennas and Propagation Society International Symposium, 2008. AP-S 2008. IEEE; 08/2008
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ABSTRACT: Since Durian has specific properties such as big peel, non-uniform shape, rough skin, etc, the system design of non-destructive maturity determination is hard to perform. This paper proposes the system designing of Durian maturity determination using microstrip patch antennas operating 2.45 GHz of microwave frequency and the measurement system which can adjust size, height, etc., to make closed environment. This method can protect the reflection of microwave to environment and measure Durian in every size. The results show that this technique can provide fast Durian maturity determination at accuracy of 72.22%.
SICE, 2007 Annual Conference; 10/2007
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ABSTRACT: This paper presents the physical layer features and structures, along with the NTT DoCoMo's proposals on solutions for the Evolved UTRA. After completion of study item investigations, outlines for physical channel structures were determined. The proposals for the orthogonal reference signal structures, multiplexing of the synchronization signal and broadcast channel appropriate to scalable multiple transmission bandwidths, the hierarchical synchronization signal structure, the downlink Layer 1 (L1) /Layer 2 (L2) control channel structure, and block-wise resource block-level distributed transmission for the shared data channel in the downlink are described. Other proposals such as purpose grouping for the random access channel in the uplink, the uplink L1/L2 control channel structure, and a link adaptation scheme for the shared data channel are also presented.
Signal Processing Advances in Wireless Communications, 2007. SPAWC 2007. IEEE 8th Workshop on; 07/2007
