http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Safety Confirmation of Ship's Crew Using Cell-phone with GPS Receiver and Wireless LAN
Chie Umeno,Hiromune Namie,Osamu Susuki,Akio Yasuda 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-
Ships and their cargos have been managed safely by positioning report system. However, little attention has been paid to safety of crew's works with danger. The attempt that used PHS inboard was before by the present authors. However, the functions were just voice call and mail exchange. The data acquisition from the terminal by proper control was not possible. Thus the position of the terminal was not available. As for the cell phone of next generation, GPS receiver and wireless LAN are installed by manufacturers. Therefore, we propose a system which uses a cell-phone with GPS receiver on a ship in order to promote the safety of ship's crew. We checked the availability of cell-phone GPS receiver at thirty different points inboard. The positioning was not possible in the areas further than 4m from the window. Then, we proposed the system which follows the positions of the crews and confirms their safety inboard by using the VoIP (Voice over Internet Protocol) function by wireless LAN.
A Novel Seamless Direct Torque Control for Electric Drive Vehicles
Ghaderi, Ahmad,Umeno, Takaji,Amano, Yasushi,Masaru, Sugai The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.
A Novel Seamless Direct Torque Control for Electric Drive Vehicles
Ahmad Ghaderi,Takaji Umeno,Yasushi Amano,Sugai Masaru 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.
Shenkun Liu,Hidenori Umeno 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
In this paper we improve TPM (Transaction Processing Monitor) and aim at a further performance enhancement of PostgreSQL. Therefore we examined introduction of mechanism to change dynamically the number of the server connections to solve the problem in this study. We investigate the number of the most suitable connection by the load situation for this introduction, and we design TPM again in various points such as the design of the mechanism to analyze server state and the design of a mechanism to change the number of the connections. We report the result of the research, the contents of design, implementation and evaluation in this paper.
Mikinori Eto,Hidenori Umeno 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Modern computers are not only sufficiently powerful but also inexpensive. However there are few opportunities for application programs to use its capabilities. On the other hand, the number of computers has been increasing in the business sectors and other fields. Thus there are a lot of needless modern computer utilizations. As these solutions, researchers interested with the utilization of virtual machines (VMs) have been rising. The VM system enables consolidation of several real machines. As we consolidate real machine, another problem occurs. It may run several the same operating systems (OSs) which have identical application program, component and data on a machine. In this case, real machine’ memory has same contents. If many machines are consolidated by VM, it is verbose. We have been developing original VM system based on open source and high-quality VM system Xen. In this paper, we improved memory management system of Xen and consider the method for decreasing verbose memory on real machine. We propose the design and implementation method of content based page sharing method in Xen.