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991.
The rise of the ‘cheaper, faster, better’ mission paradigm increasingly challenges the industrial development of satellite systems. The novel paradigm will have a profound impact on the production of the real‐time software embedded on board new‐generation systems. This paper contends that a large proportion of the ensuing demands can be satisfied by an iterative and incremental development model revolving around two evolutionary enhancements to the present engineering approach, namely (1) static real‐time analysis as a key ingredient of the software verification process, and (2) an architectural paradigm centred on fixed priority preemptive scheduling. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
992.
针对传统的交会定点测量方法存在的问题.提出了一种新的交会定点测量方法——两点边角后方交会定点测量方法.推导出了其计算公式.克服了野外测量已知点少且不通视的困难。 相似文献
993.
城市遗产保护与再利用中的房地产开发--以提篮桥历史文化风貌保护区为例 总被引:2,自引:1,他引:1
以提篮桥历史文化风貌区为例,分析了在历史文化风貌区的保护与再利用中,进行合理、适度的房地产开发所产生的经济效益,并对该风貌区中的房地产项目所做经济评价的基础上,提出了历史文化风貌区中进行房地产开发的启示和建议. 相似文献
994.
995.
应用层组播的最小延迟生成树算法 总被引:22,自引:1,他引:21
实时传输是应用层组播技术的一个主要应用领域,对网络延迟有严格的限制.保证低延迟组播成功的关键在于构建高效的应用层组播树,研究构建最小延迟应用层组播树的算法.首先分析影响延迟的3个因素:链路的传输时间、结点的发送/转发时间和结点度,然后把求解应用层组播树的问题抽象成对边和点都带权的有向图求解"度约束最小延迟生成树"的问题,同时证明这个问题属于NP-hard,并且提出了两类启发式近似算法:基于度的算法和基于最大延迟路径的算法.最后通过模拟实验说明了所提出算法的有效性. 相似文献
996.
997.
Multimedia applications handling audio and video data have to obey time characteristics of these media types. Besides a basic functionality to express time relations, correctness with respect to time constraints requires mechanisms which lead to favoured processing of multimedia operations. CPU scheduling techniques based on the experience from real-time operating systems offer a solution and provide multimedia applications with the ability to meet time-related quality of service requirements. This paper discusses mechanisms to express time in multimedia systems and describes an implementation of a CPU scheduler designed to run under IBM's UNIX derivate AIX. The evaluation of the implementation based on measurements shows that the scheduler is able to support the time requirements of multimedia applications and that such mechanisms are indeed necessary since otherwise deadline violations occur. 相似文献
998.
Patrycja Mako-Chestowska Edyta Supek Aleksandra Kramarz Jacek Gbicki 《International journal of molecular sciences》2021,22(17)
During biogas combustion, siloxanes form deposits of SiO2 on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the 1H NMR, 13C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES. 相似文献
999.
Huiquan Wu Erik Read Maury White Brittany Chavez Kurt Brorson Cyrus Agarabi Mansoor Khan 《Frontiers of Chemical Science and Engineering》2015,9(3):386-19
Compared to small molecule process analytical technology (PAT) applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufacturing biotechnology drug products. However, the use of inline Fourier transform infrared (FTIR) spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites (including glucose, glutamine, lactate, and ammonia) and protein yield at increasing levels of complexity (simple binary system, fully formulated media, actual bioreactor cell culture process) was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares (PLS) calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2nd derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed. 相似文献
1000.
随着中国经济的发展,房地产企业的竞争日趋激烈,房地产企业想要提高自身成本控制水平,就需要不断地加强项目成本控制水平。阐述了房地产项目成本控制的研究意义和现状,并从目标成本的制定、目标成本的分解、目标成本的实施与考核3个方面阐述了目标成本法的具体应用步骤。结合翰林花园项目实例,基于目标成本法指出了翰林花园项目成本控制中存在的主要问题及改进对策。 相似文献