The university timetabling problem (UTP) has been studied by numerous research groups for decades. In addition to addressing hard and soft constraints, we extend the UTP by considering consecutiveness and periodicity constraints of multi-session lectures, which are common in many eastern Asian universities. Because schedulers can decide the consecutiveness and periodicity constraints for the multi-session lectures within a limited ratio, we consider these novel decision variables in our model. We develop a mixed integer linear program for the UTP. For the analysis, we convert the UTP into the three-dimensional container packing problem (3DCPP) and create a hybrid genetic algorithm (HGA), which has been shown to be efficient in solving the 3DCPP. We also develop a tabu search algorithm based on the existing UTP literature and compare the findings with that of our HGA. The results show that our HGA obtains a better solution than the tabu search algorithm in a reasonable amount of time. 相似文献
ABSTRACTWe report on two empirical studies that explore key factors that help translate information technology governance by the board of directors into organizational performance. The first study shows that strategic alignment partially mediates the effect of board-level information technology governance on performance. The second study demonstrates that authoritarian governance style negatively moderates the effect of board-level information technology governance on performance. Together, these studies open up the black box between board-level information technology governance and organizational performance. 相似文献
Recent years have witnessed a dramatical growth of the deployment of vision-based surveillance in public spaces. Automatic summarization of surveillance videos (ASOSV) is hence becoming more and more desirable in many real-world applications. For this purpose, a novel frame-selection framework is proposed in the present paper, which has three properties: 1) un-supervision: it can work without requirements of any supervised learning or training; 2) efficiency: it can work very fast, with experiments demonstrating efficiency faster than real-timeness and 3) scalability: it can achieve a hierarchical analysis/overview of video content. The performance of proposed framework is systematically evaluated and compared with various state-of-the-art frame selection techniques on some collected video sequences and publicly-available ViSOR dataset. The experimental results demonstrate promising performance and good applicability for real-world problems. 相似文献
The Session Initiation Protocol (SIP) is a signaling protocol widely applied in the world of multimedia communication. Numerous SIP authenticated key agreement schemes have been proposed with the purpose of ensuring security communication. Farash recently put forward an enhancement employing smart cards counted on Zhang et al.’s scheme. In this study, we observe that the enhanced scheme presented by Farash has also some security pitfalls, such as disclosure of user identity, lack of a pre-authentication in the smart card and vulnerability to key-compromise masquerading attack which results in an off-line guessing attack. We then propose an anonymous modified scheme with elliptic curve cryptography to eliminate the security leakages of the scheme proposed by Farash. We demonstrate that our scheme is immune to different kinds of attacks including attacks involved in Farash’s scheme. We mention Burrows-Abadi-Needham logic for completeness of the proposed scheme. Also, we compare the performance of our scheme with its predecessor schemes and the comparative results shows that it perfectly satisfies the needs of SIP. 相似文献
Artificial immune system constructs a dynamic and adaptive information defense system through a function similar to the biological immune system. In order to resist the external invasion of useless and harmful information and ensure the effectiveness and the harmlessness of received information. Due to the low accuracy and the high false positive rate of the existing clonal selection algorithms applied to intrusion detection, in this paper, we propose an improved clonal selection algorithm. The improved method detects the intrusion behavior by selecting the best individual overall and cloning them. Experimental results show that the improved algorithm achieves very good performance when applied to intrusion detection. And it is shown that the algorithm is better than BP neural network with its 99.5 % accuracy and 0.1 % false positive rate. 相似文献
In this paper, an interactive dynamic simulation method is proposed to solve computational models of soft tissue undergoing large deformation, collision detection, and volume conservation in medical surgical simulation visualization. During the process of implementation of the interactive dynamic simulation method, the point-based method is used to simulate the elastic solids undergoing large deformations and the position-based method is used to simulate the objects collision, friction and volume conservation. Numerical results demonstrate that the proposed method improves the efficiency and stability of the response of heterogeneous soft tissue undergoing contact or even the multi-organs interactions, and it can be extended to interactive biopsy and cutting simulation.
Multimedia Tools and Applications - Pictures spreading on the Internet are essential for the authenticity of events. Each day, huge amounts of data are published on social media, and many of them... 相似文献
This paper proposes a new ITPS panel with special corrugated-core webs which are designed with cutouts for weight saving. The structural design problem was formulated with mass per unit area of the ITPS as the objective function and some functional requirements as constraints. We developed the optimizer fulfilling both thermal and structural functions for minimal areal density. The optimization problem was solved by interpolating the residual error of response surface approximation (RSA) with Radial Basis Function (RBF) to establish the improved RSA (IRSA). The 400 preliminary design points were obtained using Latin Hypercube Sampling method. The quadratic polynomial RSA of the ITPS sandwich panel performance was generated by the least squares method (LSM) based on finite element results and IRSA was used to optimize the constraints. Transient heat transfer, stress and buckling analyses were conducted using finite element method (FEM). Finally, a new ITPS panel with optimal dimensions was obtained. The optimization results show that the areal density of the new ITPS panel decreases by 26.27 % compared with the previous research, which proves the potential of this new design optimization method for the future spacecraft vehicles. 相似文献