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Signal Restoration of Broad Band Speech Using Adaptive Digital Filter
Yasukawa, Hiroshi 대한전자공학회 1994 ISPACS:Intelligent Signal Processing and Communica Vol.1 No.1
This paper focuses on restoring band limited speech signals to obtain highly quality speech by reproducing the upper band speech power. Two methods that offer simple and easy implementation are introduced. One method is automatic level control. The other introduces frequency domain adaptive digital filtering to broaden band limited signals into wide band signals, namely we find the optimum inverse transfer function to convert band limited signals back into the original broad band signals. Implementation of the system and its performance are discussed.
Yasukawa Taiki,Ohya Junichi,Kawamura Naohiro,Yoshida Yuichi,Onishi Yuki,Kohata Kazuhiro,Kakuta Yohei,Nagatani Satoshi,Kudo Yoshifumi,Shirahata Toshiyuki,Kunogi Junichi 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.5
Study Design: Clinical case series.Purpose: This study aimed to report dynamization–posterior lumbar interbody fusion (PLIF), our surgical treatment for hemodialysisrelated spondyloarthropathy (HSA), and investigate patients’ postoperative course within 2 years.Overview of Literature: HSA often requires lumbar fusion surgery. Conventional PLIF for HSA may cause progressive destructive changes in the vertebral endplate, leading to progressive cage subsidence, pedicle screw loosening, and pseudoarthrosis. A dynamic stabilization system might be effective in patients with a poor bone quality. Thus, we performed “dynamization–PLIF” in hemodialysis patients with destructive vertebral endplate changes.Methods: We retrospectively examined patients with HSA who underwent dynamization–PLIF at our hospital between April 2010 and March 2018. The radiographic measurements included lumbar lordosis and local lordosis in the fused segment. The evaluation points were before surgery, immediately after surgery, 1 year after surgery, and 2 years after surgery. The preoperative and postoperative radiographic findings were compared using a paired t-test. A p-value of less than 0.05 was considered significant.Results: We included 50 patients (28 males, 22 females). Lumbar lordosis and local lordosis were significantly improved through dynamization– PLIF (lumbar lordosis, 28.4°–35.5°; local lordosis, 2.7°–12.8°; <i>p</i><0.01). The mean local lordosis was maintained throughout the postoperative course at 1- and 2-year follow-up (12.9°–12.8°, p=0.89 and 12.9°–11.8°, <i>p</i>=0.07, respectively). Solid fusion was achieved in 59 (89%) of 66 fused segments. Solid fusion of all fixed segments was achieved in 42 cases (84%). Within 2 years postoperatively, only six cases (12%) were reoperated (two, surgical debridement for surgical site infection; two, reoperation for pedicle screw loosening; one, laminectomy for epidural hematoma; one, additional fusion for adjacent segment disease).Conclusions: Dynamization–PLIF showed local lordosis improvement, a high solid fusion rate, and a low reoperation rate within 2 years of follow-up.
High-speed and Precise Geometric Correction in Consideration of Elevation for GMS S-VISSR Data
YASUKAWA, Masaki,TAKAGI, Mikio 대한원격탐사학회 2001 International Symposium on Remote Sensing Vol.17 No.1
In order to process GMS-5 S-VISSR data immediately after reception and provide academic researchers the geometrically corrected data useful For the time series analysis, a high-speed and precise geometric correction method in consideration of the elevation is described. As preprocessing, systematic residual errors considering the elevation are acquired on image coordinate, and the coefficient of the affine transformation is calculated using the errors. For a high-speed and precise geometric correction, the processing is carried out as follows: For first computation, the output image on map coordinate is divided into the blocks. Each correspondence between latitude-longitude on map coordinate and line-pixel on image coordinate is calculated by systematic geometric transformation for the four corners of the block, and the afghan transformation and the correction of the elevation error are carried out toward the line-pixel. In the case of internal points excluding four corners in the block, each correspondence of line-pixel and latitude-longitude is calculated by bi-linear interpolation using correspondences of the four corners for speeding up the geometric correction. If the interpolation error is more than 0.5 pixels because of the rapid change on elevation in the block, the block is divided into the small blocks. In case that the interpolation error is less than p.5 pixels at the small block, bi-linear interpolation is applied to the small block. In other case, the systematic geometric transformation is applied to the small block. As the result, the accuracy at the high elevation areas was improved greatly. The processing time of the output image generation on map coordinate was about 13 minutes, and speeding up the geometric correction was successful.
Integrated Database System for GMS-5 VISSR Data
Yasukawa, Masaki,Takagi, MiKio 대한원격탐사학회 2000 International Symposium on Remote Sensing Vol.16 No.1
In order to promote academic researchers on long term variations of land, ocean and atmosphere in Asia, scientific data sets such as NOAA AVHRR (Advanced Very High Resolution Radiometer) and GMS-5 VISSR (Visible and Infrared Spin Scan Radiometer) images mapped into map coordinate, vegetation index, sea surface temperature, cloud distribution and so on are required. Because of huge data size, particular format and complicate algorithms, it is difficult for academic researchers to make products such as level 1, 2 and 3. The aim of this research is to generate databases of GM5 images including products of level 1, 2 and 3 and to provide these various data sets fox researchers via network. In this paper, how to process the transferred GMS data every hour via network and how to generate and archive products such as level 1, 2 and 3 in the integrated processing system are described. The integrated processing system includes transactions of geometric correction, cloud mask generation, cloud classification map and sea surface temperature map. Generated products are archived in hierarchical databases using disk arrays and DLT (Digital Linear Tape) library. Thus, academic researchers can utilize various products from GMS data observed every hour, and spatial arid temporal understandings of global environment become possible.
Effect of Load Condition on Turning Performance of a VLCC in Adverse Weather Conditions
Zaky, Mochammad,Yasukawa, Hironori Korean Society of Ocean Engineers 2018 Journal of advanced research in ocean engineering Vol.4 No.2
The load condition significantly influences ship maneuverability in calm water. In this research, the effect of the load condition on turning performance of a very large crude oil carrier (VLCC) sailing in adverse weather conditions is investigated by an MMG-based maneuvering simulation method. The relative drift direction of the ship in turning to the wave direction is $20^{\circ}-30^{\circ}$ in ballast load condition (NB) and full load condition (DF) with a rudder angle $35^{\circ}$ and almost constant for any wind (wave) directions. The drifting displacement in turning under NB becomes larger than that under DF at the same environmental condition. Advance $A_d$ and tactical diameter $D_t$ become significantly small with an increasing Beaufort scale in head wind and waves when approaching, although $A_d$ and $D_t$ are almost constant in following wind and waves. In beam wind and waves, the tendency depends on the plus and minus of the rudder angle.