Mechanical performance of ceramic matrix composite I-beams

Experimental studies have been performed on ceramic matrix composite (CMC) I-sections, which typify joint designs for CMC components. Axial loads and moments have been applied to activate delamination mechanisms. The maximum load bearing capacity has large variability, governed by the severity of manufacturing flaws located in the transition region of the I-section. This variability leads to an unsatisfactory design situation. Delaminations that form from these flaws arrest and behave in a stable manner, subject to a remanent load bearing capacity. This remanent capacity has minimal variability. Hence, design based on the remanent load would be robust. An expression for this design criterion is presented.     

基于交流比例积分控制器的单相逆变器

提出一种电感电流、输出电压瞬时值反馈控制和负载电流前馈控制相结合的复合控制策略。在此基础上,研制了一台800W的单相逆变器。实验结果表明,提出的控制策略改善了逆变器输出电压的波形,提高了系统的暂态特性。     

A note on circle packing

The problem of packing circles into a domain of prescribed topology is considered. The circles need not have equal radii. The Collins-Stephenson algorithm computes such a circle packing. This algorithm is parallelized in two different ways and its performance is reported for a triangular, planar domain test case. The implementation uses the highly parallel graphics processing unit (GPU) on commodity hardware. The speedups so achieved are discussed based on a number of experiments.     

基于视频的现实人物运动创作

提出一种根据用户指定的人体运动和观察视角生成真实感视频的方法.首先采集演员进行少数基本运动时的多视角视频数据库,并使用无标记运动捕捉的方法获得任意时刻人体对应的骨骼和3D模型.其次,用户对人体骨架指定运动并设定视角,以此定义目标视频.实验结果验证了文中方法能够利用有限的数据库合成演员在用户指定运动和视角下的真实感视频.     

海量数据库迁移与升级

目前数据库中数据越来越多,应用对数据库在线时间的要求也越来越高,使得数据库迁移和数据库升级成为了一件非常困难的事情.为此,介绍了几种迁移和升级的方法,用以实现以尽可能少的停机时间对TB级数据库完成数据库的迁移和升级.     

The effects of long-term VDT usage on the nature and incidence of asthenopic symptoms

An opportunity arose in 1985 to become involved in a transition of working practice from hard copy to VDT. Over a two-year period, 161 VDT users and 65 control subjects in the same office environment were regularly and routinely examined for symptoms of asthenopia. The analysis of data shows that there are no significant differences in type, number and frequency of the work-related symptoms between VDT users and non-VDT users. It appears that reporting of symptoms within the group may be random, although certain symptoms do appear more frequently than others. Additionally, it appears that there is a significant difference between male and female users in the frequency of symptom reporting.     

Analysis of oceanaut operating performance using an integrated Bayesian network aided by the fuzzy logic theory

Because the oceanaut plays a significant role in safety and capability during manned deep-diving scientific tasks, preventing oceanaut performance decline is of paramount importance. However, the factors responsible for oceanaut performance are almost entirely unexplored. To address the preceding issues, a quantitative method of fuzzy integrated Bayesian network (FIBN) was modeled within the limits of oceanaut operating procedures. To quantify the probabilities of the influencing factors, the probability of each node in the FIBN was calculated using integrated expert judgement, fuzzy logic theory, and Bayesian network. By considering a total of 28 factors related to oceanaut performance in the “Jiaolong” manned submersible, this study found that difficult sampling, long sampling times, cabin equipment failure, oceanaut physical decline, and declining decision-making ability are important factors that affect oceanaut performance. The FIBN proposed in our study fused the qualitative and quantitative methods and can be developed into a versatile tool for analysis of comprehensive systems that contain both static and dynamic factors.Relevance to industryThe results provide a powerful basis for the design of manned submersible and assignment of tasks to oceanauts, while the fuzzy integrated Bayesian network (FIBN) method proposed can be effectively applied to various quantitative assessment fields which direct researchers to deal with analysis problems of complex systems.     

Multi-indicator Active Queue Management Method

A considerable number of applications are running over IP networks. This increased the contention on the network resource, which ultimately results in congestion. Active queue management (AQM) aims to reduce the serious consequences of network congestion in the router buffer and its negative effects on network performance. AQM methods implement different techniques in accordance with congestion indicators, such as queue length and average queue length. The performance of the network is evaluated using delay, loss, and throughput. The gap between congestion indicators and network performance measurements leads to the decline in network performance. In this study, delay and loss predictions are used as congestion indicators in a novel stochastic approach for AQM. The proposed method estimates the congestion in the router buffer and then uses the indicators to calculate the dropping probability, which is responsible for managing the router buffer. The experimental results, based on two sets of experiments, have shown that the proposed method outperformed the existing benchmark algorithms including RED, ERED and BLUE algorithms. For instance, in the first experiment, the proposed method resides in the third-place in terms of delay when compared to the benchmark algorithms. In addition, the proposed method outperformed the benchmark algorithms in terms of packet loss, packet dropping, and packet retransmission. Overall, the proposed method outperformed the benchmark algorithms because it preserves packet loss while maintaining reasonable queuing delay.     

Artificial intelligence capability: Conceptualization,measurement calibration,and empirical study on its impact on organizational creativity and firm performance

Artificial intelligence (AI) has been heralded by many as the next source of business value. Grounded on the resource-based theory of the firm and on recent work on AI at the organizational context, this study (1) identifies the AI-specific resources that jointly create an AI capability and provides a definition, (2) develops an instrument to capture the AI capability of the firms, and (3) examines the relationship between an AI capability and organizational creativity and performance. Findings empirically support the suggested theoretical framework and corresponding instrument and provide evidence that an AI capability results in increased organizational creativity and performance.