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Performance Enhancement of TFI-OFDM with Path Selection based Channel Identification
Takeshi Yoshimura,Chang-Jun Ann,Takeshi Kamio,Hisato Fujisaka,Kazuhisa Haeiwa 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
Recently time-frequency interferometry (TFI)-OFDM has been proposed as a channel identification scheme. TFI-OFDM system can multiplex the same impulse response in twice on the time domain without overlapping to each other. In this case, the required pilot signal is only one. Moreover, by averaging of these impulse responses, the accurated channel impulse responses are obtained. However, if the total channel paths are reduced, the performance might be degraded. This is because the channel identification of TFI-OFDM is operated with averaging the selected spectrum signals from the time windows. For the case with reduced channel paths, the selected time spectrum signals include the noise terms. By applying the FFT operation, these noise terms are spread in the frequency domain. In this case, the channel identification is poorly operated due to the noise. To reduce this problem, in the paper, we propose the channel identification method with path selection for performance enhancement of TFI-OFDM.
Takeshi Kobayashi,Toshiaki Imanishi,Taizo Hanai,Ichiro Aoyagi,Jun Uemura,Katsuhiro Araki,Hiroshi Yoshimoto,Takeshi Harima,Hiroyuki Honda 한국생물공학회 2002 Biotechnology and Bioprocess Engineering Vol.7 No.5
In order to control glucose concentration during fed-batch culture for antibiotic production, we applied so called “software sensor” which estimates unmeasured variable of interest from measured process variables using software. All data for analysis were collected from industrial scale cultures in a pharmaceutical company. First, we constructed an estimation model for glucose feed rate to keep glucose concentration at target value. In actual fed-batch culture, glucose concentration was kept at relatively high and measured once a day, and the glucose feed rate until the next measurement time was determined by an expert worker based on the actual consumption rate. Fuzzy neural network (FNN) was applied to construct the estimation model. From the simulation results using this model, the average error for glucose concentration was 0.88 g/L. The FNN model was also applied for a special culture to keep glucose concentration at low level. Selecting the optimal input variables, it was possible to simulate the culture with a low glucose concentration from the data sets of relatively high glucose concentration. Next, a simulation model to estimate time course of glucose concentration during one day was constructed using the on-line measurable process variables, since glucose concentration was only measured off-line once a day. Here, the recursive fuzzy neural network (RFNN) was applied for the simulation model. As the result of the simulation, average error of RFNN model was 0.91 g/L and this model was found to be useful to supervise the fed-batch culture.
Takeshi Sasagawa,Hideki Murakami,Yoshinobu Maruhashi,Takeshi Segawa,Daiki Yamamoto,Shusuke Shimizu,Yasuhiko Morita,Takuya Nakamura 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.5
Vertebral fractures occur with only slight trauma in patients with diffuse idiopathic skeletal hyperostosis (DISH). However, a lumbar vertebra fracture, due to an intraoperative body position has not been previously reported. An 87-year-old woman with kyphosis sustained a left trochanteric fracture of her femur. The patient was placed in a supine position during the operation. Postoperatively, the patient experienced severe right thigh pain. Magnetic resonance imaging revealed an L4 vertebral fracture. Computed tomography revealed ankylosis from the upper thoracic spine to the sacrum. While in a supine position under general anesthesia, the contact of the patient’s lower back with operating table likely created a fulcrum at her lumbosacral spine acting as a long lever arm, bearing the mass of her upper body. We performed L1–S2 posterior stabilization. DISH patients with kyphosis placed in a supine position have an increased risk for lumbar vertebral fracture.
Takeshi Sasaki,Shota Jikumaru,Wakana Azuma,Keiko Kuroda,Hiroaki Ishii 한국산림과학회 2016 Forest Science And Technology Vol.12 No.3
The larvae of Japanese gypsy moth (JGM, Lymantria dispar japonica) are highly polyphagous and considered a serious pest that cause significant ecological and economic losses in forests. Monitoring of egg masses is important to prevent large outbreaks of JGM from occurring in their native range. To investigate oviposition site selection by JGM, we analyzed the occurrence and spatial distribution of egg masses across various evergreen tree species within a secondary forest dominated by evergreen broad-leaved trees in western Japan, following a large outbreak. Egg masses were concentrated on the abaxial surfaces of the leaves of a few evergreen tree species. There was a strong preference for Camellia japonica L., on which more than 75% of the egg masses were found. Egg masses were only found on evergreen tree species with large leaves (leaf area >10 cm2 and leaf dry mass >0.1 g). The spatial distribution of egg masses were clustered at scales around 1‒2 m. For effective monitoring of JGM egg masses in warm-temperate evergreen broad-leaved forests of Japan, the abaxial surfaces of the most abundant evergreen broadleaved trees with large leaves should be checked. If egg masses are found, it is likely that nearby trees of the same species
Takeshi Sasakia,Junichi Imanishi,Wataru Fukui,Fukiko Tokunaga,Yukihiro Morimoto 한국산림과학회 2012 Forest Science And Technology Vol.8 No.3
Light detection and ranging (LiDAR) is an active remote sensing technology that can be used to directly acquire three-dimensional forest information, and it has great potential to replace traditional time-consuming field surveys. We aimed to determine the accuracy with which enhanced airborne LiDAR with high density (mean, 47points m^-2) can replicate detailed vertical foliage arrangement and three forest structural indices, i.e. number of layers (NSTRAT), sum of the percent vegetation cover (PCVC), and foliage height diversity (FHD), all of which are useful for characterizing avian habitats. Thirteen 40-m-long lines were set in an urban forest area, and LiDAR-based and field-based cross-sectional profiles with 161-m meshes were compared. In addition, we performed random LiDAR point thinning to determine whether the replications were possible with lower point densities. The 161-m mesh vertical foliage arrangements were replicated with high accuracy by using LiDAR (mean producer’s accuracy, 0.756; mean user’s accuracy, 0.810) before the point reduction. All the three indices were also replicated with high accuracy (<0.12 of the relative root mean square error for the 1:1 relationship). Even when the mean point density was reduced to 2.4 points m72, the three indices could be quantitatively estimated with high accuracy by using simple linear regression analyses (>0.8 in R^2). For NSTRAT and FHD,numerical replication was possible with high accuracy (<0.2 and <0.1, respectively, of the relative root mean square error for the 1:1 relationship), even when the mean point density was reduced to 2.4 points m^-2. In conclusion, enhanced high-density LiDAR seems to be highly suitable as a substitute for field surveys for delineating detailed vertical forest structure in order to characterize forest avian habitats. Moreover, lower-density LiDAR data could replicate the forest structural indices, suggesting its useful low-cost application in quantitative avian habitat models.
Takeshi Takeda,Iwao Ohtsu 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.6
An experiment was conducted for the OECD/NEA ROSA-2 Project using the large-scale test facility (LSTF),which simulated a 17% hot leg intermediate-break loss-of-coolant accident in a pressurized water reactor(PWR). In the LSTF test, core uncovery started simultaneously with liquid level drop in crossover legdownflow-side before loop seal clearing, and water remaining occurred on the upper core plate in theupper plenum. Results of the uncertainty analysis with RELAP5/MOD3.3 code clarified the influences ofthe combination of multiple uncertain parameters on peak cladding temperature within the defineduncertain ranges. For studying the scaling problems to extrapolate thermal-hydraulic phenomenaobserved in scaled-down facilities, an experiment was performed for the OECD/NEA PKL-3 Project withthe Primarkreislaufe Versuchsanlage (PKL), as a counterpart to a previous LSTF test. The LSTF testsimulated a PWR 1% hot leg small-break loss-of-coolant accident with steam generator secondary-sidedepressurization as an accident management measure and nitrogen gas inflow. Some discrepanciesappeared between the LSTF and PKL test results for the primary pressure, the core collapsed liquid level,and the cladding surface temperature probably due to effects of differences between the LSTF and thePKL in configuration, geometry, and volumetric size.