During initial bull form design, a multitude of requirements need to be met. Among these are mission, ship size, armament, communications, stability, speed, sea keeping, etc. Tools such as ASSET are used to arrive at ...
During initial bull form design, a multitude of requirements need to be met. Among these are mission, ship size, armament, communications, stability, speed, sea keeping, etc. Tools such as ASSET are used to arrive at a design solution that will satisfy all these requirements. However, at this early design stage, attention needs to be given to the bull form shape, and its impact upon fuel consumption. Rising fuel costs and the need to conserve energy have mandated that Navy designs become more "energy efficient." This paper documents a new design metric "C-PE" for evaluating the resistance of any bull design. A C-PE database is developed from historic model test data residing in the U.S. Navy Hull design Database system (HDDS). C-PE compares the resistance of a bull form to that of a similar Taylor Standard Series bull form. The paper also introduces a new bull form optimization computer program developed by Naval Surface Warfare Center (NSWC) and applies this program to show the potential for hull form improvement and fuel cost savings.
The objective of this paper is to provide an analytical basis for the quantitative evaluation of damage to a reinforced concrete structure based on the vibration data obtained by using the damage detection technique. ...
详细信息
The objective of this paper is to provide an analytical basis for the quantitative evaluation of damage to a reinforced concrete structure based on the vibration data obtained by using the damage detection technique. A partial reinforced concrete system of a weak beam/strong column moment frame is chosen as an example. A pushover analysis is carried out in order to numerically examine both the story shear-relative displacement characteristics and the associated damage level. In the analysis, a two dimensional nonlinear finite element analysis is employed considering several constitutive models. As a result, the degradation of the stiffness at the damaged story is characterized in association with the story relative displacement. It is also pointed out that the rotation angle of the column-base is highly correlated with the story relative displacement. Based on the analytical findings, quantitative approaches for a structural health monitoring system are suggested considering both the current sensor technologies and those available in the future.
Keywords nonlinear FEM analysis - structural health monitoring - reinforced concrete structure - story stiffness - rotation angle of column-base
Supported by: Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (Base Research (c) (1), Research No. 14550555)
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are ind...
详细信息
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are individually weighted and added together. For Doppler spread signal, it alters fading statistics and improves the bit error rate. Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.
The space-time-frequency processing for OFDM wireless mobile communications was presented. The novel space-time-frequency processing schemes for OFDM mobile communication systems were implemented by using antenna arra...
详细信息
The space-time-frequency processing for OFDM wireless mobile communications was presented. The novel space-time-frequency processing schemes for OFDM mobile communication systems were implemented by using antenna arrays. It was stated that, when the angular spread is small, multiple antennas might not be able to provide space diversity.
A study was performed on Doppler diversity for orthogonal frequency-division multiplexing (OFDM) wireless mobile communications. A novel time-frequency processing scheme was developed to exploit Doppler diversity. The...
详细信息
A study was performed on Doppler diversity for orthogonal frequency-division multiplexing (OFDM) wireless mobile communications. A novel time-frequency processing scheme was developed to exploit Doppler diversity. The extensive simulations showed that the proposed time-frequency MMSE processing scheme altered the statistics of the fading to improve BER significantly.
A novel time-frequency processing scheme is developed to exploit Doppler diversity of time varying multipath channel for OFDM mobile communication systems. Extensive simulations show that the proposed time-frequency M...
详细信息
ISBN:
(纸本)0780377575
A novel time-frequency processing scheme is developed to exploit Doppler diversity of time varying multipath channel for OFDM mobile communication systems. Extensive simulations show that the proposed time-frequency MMSE processing scheme alters the statistics of the fading to improve BER significantly.
Novel space-time-frequency processing schemes for OFDM mobile communication systems are implemented using antenna arrays, tap delay lines and Doppler branches to exploit angular spread, delay spread and Doppler spread...
详细信息
ISBN:
(纸本)0780377575
Novel space-time-frequency processing schemes for OFDM mobile communication systems are implemented using antenna arrays, tap delay lines and Doppler branches to exploit angular spread, delay spread and Doppler spread, respectively.
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are ind...
详细信息
ISBN:
(纸本)0780377575
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are individually weighted and added together. For Doppler spread signal, it alters fading statistics and improves the bit error rate. Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.
The purpose of this study is to evaluate and analyze the Chitlada State Railway of Thailand (SRT) Housing in Bangkok by examining at the transition of multipurpose space of row houses. Row houses at Chitlada are made ...
详细信息
Through analysis of its terrestrial use, the unique concept of the Japanese House where the habitat experiences several transformations during the day is applied to the space habitation module. In addition, the concep...
详细信息
暂无评论