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Development of a Multi-Channel Processing Matched Filter Using FPGA for CDMA-QAM Method
Hiroshi Mochizuki,Sei Takahashi,Hideo Nakamura,Satoshi Nishida,Ryo Ishikawa 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
At present, we attempt to apply our proposed CDMA-QAM method to railway signaling, and evaluate basic characteristics using computer simulation. In this paper, we describe development of a multichannel processing matched lter as a CDMA receiver. We noted that Walsh code is 1 or -1, and proposed the design that has no multipliers. In addition, we applied some techniques such as time-sharing processing, and optimized the design to reduce number of logic elements that an FPGA has. As a result, we show that we could implement the multi-channel processing matched lter in an FPGA.
Hiroshi Mochizuki,Sei Takahashi,Hideo Nakamura,Satoshi Nishida,Ryo Ishikawa 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
In this paper, we propose a new modulation method combining code-division multiple access (CDMA) and quadrature amplitude modulation (QAM), called CDMAQAM. It transmits QAM symbols allocated based on a CDMA signal, and it has the benefit that QAM errors can be recovered if they are in a range where they can be absorbed by CDMA demodulation. We applied the method to railway signaling and developed a CDMA-QAM rail transmission system having a transmission speed of 1500 bps using digital signal processors. We also conducted a field experiment using an actual rail and verified that the system can achieve favorable constellation characteristics.
( Osamu Tanifuji ),( Tomoharu Mochizuki ),( Hiroshi Yamagiwa ),( Takashi Sato ),( Satoshi Watanabe ),( Hiroki Hijikata ),( Hiroyuki Kawashima ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-
Purpose: The purpose of this study was to evaluate the post-operative three-dimensional (3D) femoral and tibial component positions in total knee arthroplasty (TKA) by the same co-ordinates’ system as for pre-operative planning and to compare it with a two-dimensional (2D) evaluation. Materials and methods: Sixty-five primary TKAs due to osteoarthritis were included. A computed tomography (CT) scan of the femur and tibia was obtained and pre-operative 3D planning was performed. Then, 3D and 2D postoperative evaluations of the component positions were performed. KneeCAS (LEXI, Inc., Tokyo, Japan), a lowerextremity alignment assessment system, was used for the 3D post-operative evaluation. Standard short-knee radiographs were used for the 2D post-operative evaluation. Differences between the pre-operative planning and post-operative coronal and sagittal alignment of components were investigated and compared with the results of the 3D and 2D evaluations. Results: According to the 3D evaluation, the difference between the pre-operative planning and actual postoperative sagittal alignment of the femoral component and the coronal and sagittal alignments of the tibial component were 2.6° ± 1.8°, 2.2° ± 1.8° and 3.2° ± 2.4°, respectively. Using the 2D evaluation, they were 1.9° ± 1.5°, 1.3° ± 1.2° and 1.8° ± 1.4°, making the difference in 3D evaluation significantly higher (p = 0.013, = 0.003 and < 0.001). For the sagittal alignment of the femoral component and the coronal and sagittal alignment of the tibial component, the outlier ( > ± 3°) ratio for the 3D evaluation was also significantly higher than that of the 2D evaluation (p < 0.001, = 0.009 and < 0.001). Conclusions: The difference between the pre-operative planning and post-operative component alignment in the 3D evaluation is significantly higher than that of the 2D, even if the same cases have been evaluated. Twodimensional evaluation may mask or underestimate the post-operative implant malposition. Three-dimensional evaluation using the same co-ordinates’ system as for pre-operative planning is necessary to accurately evaluate the post-operative component position.
Formal Analysis of Automatic Train Protection and Block System for Regional Line Using VDM++
Xie, Guo,Hei, Xinhong,Mochizuki, Hiroshi,Takahashi, Sei,Nakamura, Hideo The Korean Society for Railway 2012 International Journal of Railway Vol.5 No.2
This paper introduced a novel railway system, Automatic Train Protection and Block (ATPB) briefly, which is proposed to improve the efficiency of existing regional train lines with low cost in Japan. The biggest superiority of ATPB system is a great use of universal and mature technologies, such as GPS and regular mobile telephone networks, so that there is nearly no increment of trackside equipments in the reconstruction. Then in order to guarantee the system safety, a formal model of ATPB is established and analyzed by formal method VDM++. Firstly, the specification is specified by VDM++ formally without ambiguity. Secondly, its internal consistency is proved by discharging the proof obligations. And finally, its satisfiability is checked by systematic testing, which executes specification and checks the outputs against corresponding inputs.
Formal Analysis of Automatic Train Protection and Block System for Regional Line Using VDM++
Guo Xie,Xinhong Hei,Hiroshi Mochizuki,Sei Takahashi,Hideo Nakamura 한국철도학회 2012 International Journal of Railway Vol.5 No.2
This paper introduced a novel railway system, Automatic Train Protection and Block (ATPB) briefly, which is proposed to improve the efficiency of existing regional train lines with low cost in Japan. The biggest superiority of ATPB system is a great use of universal and mature technologies, such as GPS and regular mobile telephone networks, so that there is nearly no increment of trackside equipments in the reconstruction. Then in order to guarantee the system safety, a formal model of ATPB is established and analyzed by formal method VDM++. Firstly, the specification is specified by VDM++ formally without ambiguity. Secondly, its internal consistency is proved by discharging the proof obligations. And finally, its satisfiability is checked by systematic testing, which executes specification and checks the outputs against corresponding inputs.