In this study, an innovative adaptive and intelligent web based e-learning system, UZWEBMAT (Turkish abbreviation of Adaptive and INtelligent WEB based MAThematics teaching–learning system) was designed, developed and implemented. This e-learning system was intended for learning and teaching secondary school level permutation-combination-binomial expansion and probability subjects. Content which was prepared according to Turkish curriculum for secondary school mathematics course was transformed into learning objects in three different ways in accordance with VAK (Visual–Auditory–Kinesthetic) learning styles. Primary/secondary/tertiary learning styles of learners registering the system are determined and each learner receives the content appropriate for his/her dominant learning style. Also, they can be directed to contents of other styles according to their performances thanks to an expert system. Learning objects constituting the content were prepared according to constructivist approach. An active role for the learner was the purpose. Tips and intelligent solution supports within the learning objects were presented with expert system support to the learners. With this structure, UZWEBMAT bears the characteristics of intelligent tutoring system as well as an adaptive e-learning environment. All the movements of learners studying with UZWEBMAT are recorded and the necessary information is reported to both learners and teachers in a visualized way. 相似文献
A mixed integer linear programming model is formulated for determining the optimum plan for the expansion of the Saudi Arabian petrochemical industry. The products selected for consideration fall into four categories: propylene derivatives, ethylene derivatives, synthesis gas derivatives, and aromatic derivatives. The model incorporates new variables and constraints, and realistic estimates of production costs, which are calculated based on local conditions in Saudi Arabia. For each production process, the unit production cost is assumed to be a function of production capacity. The input data for each product includes relevant production technologies, capacities, local production costs, and selling price. The solution of the model gives the recommended products under different scenarios of available capital investment and feedstock. The results are reported and analyzed. 相似文献
Western Turkey contains both spectacular palaeotectonic and neotectonic features of the Anatolian block. The first of these features is the Menderes Massif, a huge metamorphic terrain comprising various lithologies; the second is the Gediz Graben, one of the most well‐known extensional features that formed during the neotectonic period of Turkey's complex geological history. In the study area, approximately E–W‐trending Neogene grabens, such as the Gediz, obliquely subdivide palaeotectonic massifs (such as the NE–SW‐oriented Menderes Massif) and mélange rocks. The terms Menderes Massif and Gediz Graben indicate different products of different tectonic regimes. In this study, lithological components of the region were determined using a Landsat Thematic Mapper (TM) image. Band‐ratioing and principal component analysis (PCA) were chosen for lithological discrimination of the outcropping geological units. After processing, PCA gave the best results in terms of lithological differentiation. Furthermore, certain band‐ratio colour composites (5/7, 5/4, 4/1) are sensitive to lithological differences in RGB (red, green and blue) space and thus provide a general understanding of the distribution of rock‐forming minerals, such as known hydroxyl‐bearing and ferric iron minerals, as well as the vegetative characteristics of the region. However, a structural‐analysis study, including visual inspection and edge‐enhancement techniques, played a complementary role in the geological analysis of the region. Outcrops of the Menderes Massif metamorphic rocks, mélange rocks and Neogene cover associated with the Gediz Graben are favourable for remote sensing studies in so far as they allow ease of interpretation and geological evaluation by researchers. One of the most notable results derived from this study was the discrimination of younger neotectonic, fluviatile occurrences from the palaeotectonic Menderes Massif metamorphic rocks and Izmir–Ankara Suture Zone mélange rocks. Additionally, boundaries of the active Gediz Graben have been delineated. 相似文献
Joint roughness has a critical role in the deformation behavior of discontinuous rock masses. Several subjective (visual comparison) and quantitative (statistical and fractal) approaches have been proposed for estimating rock joint roughness coefficient (JRC). Using a large collection of 223 published joint profiles, this study investigates variability of the JRC estimates by these approaches. Among the profile parameters, maximum height (Rz), ultimate slope (λ), and fractal dimension (Dh–L, determined using the hypotenuse leg method) show a lower sensitivity to the sampling interval than the root mean square of the first deviation (Z2), profile elongation index (δ), fractal dimension (Dc, determined using the compass-walking method), and standard deviation of the angle i (σi). Accordingly, this study proposes two separate sets of equations for quantitatively estimating JRC. The performances of these equations are examined by performing direct shear tests on 23 rock joint samples. The subjective approach is found to underestimate JRC by less than two units because it ignores (1) the main trend of the compared profile and (2) the limited scope of the standard profiles. Following these results, the visual comparison chart is updated by explicitly adding a scale bar for the y-axes of the standard profiles. Several basic rules for visual comparisons are also proposed.
A modified size exchange chromatography method is used to obtain molecular weight distributions, average molecular weight, and other characteristics of heavy oil residues: coal asphalt, petroleum asphalt, vacuum residue oil, and ethylene residue oil. This method can be applied for developing and studying processes involved in hydrogenation of heavy oil residues, road asphalt production, and coal liquefaction. 相似文献
Live virtual machine migration is one of the most promising features of data center virtualization technology. Numerous strategies have been proposed for live migration of virtual machines on local area networks. These strategies work perfectly in their respective domains with negligible downtime. However, these techniques are not suitable to handle live migration over wide area networks and results in significant downtime. In this paper we have proposed a Machine Learning based Downtime Optimization (MLDO) approach which is an adaptive live migration approach based on predictive mechanisms that reduces downtime during live migration over wide area networks for standard workloads. The main contribution of our work is to employ machine learning methods to reduce downtime. Machine learning methods are also used to introduce automated learning into the predictive model and adaptive threshold levels. We compare our proposed approach with existing strategies in terms of downtime observed during the migration process and have observed improvements in downtime of up to 15 %. 相似文献
This experimental study focused on improving performance characteristics of a low-heat rejection (LHR) diesel engine operating with biodiesel fuel. To ensure LHR conditions, the cylinder head and valves of the test engine were coated with a Y2O3-ZrO2 (yttria-stabilized zirconia) layer of 0.35?mm thickness over a NiCrAl bond coat of 0.15?mm thickness. The fuel used in the engine tests was produced from sunflower oil with transesterification methods. The engine test results showed that brake-specific fuel consumption (BSFC) and brake thermal efficiency were improved with biodiesel usage and thermal barrier coating (TBC) application. Further, exhaust gas temperature was decreased with use of biodiesel, while it was increased with TBC application. 相似文献
Proxy Mobile IPv6 (PMIPv6) is a network based mobility protocol which has been designed to relieve the mobile nodes (MNs) from participating in the mobility process and to reduce the long handoff latency of the MIPv6 protocol. However, PMIPv6 incurs a long communication path due to the triangle routing problem, in which, all packets sent by MNs are obligated to pass through the local mobility anchor. Several solutions have been proposed to mitigate this issue. However, they still incur high signaling overhead to recover the Route Optimization (RO) status after handoff. In this paper, we propose a Cluster-Based RO (CBRO) scheme for the clustered architecture of the PMIPv6, in which, the Mobile Access Gateways (MAGs) are grouped into clusters with a distinguished Head MAG (HMAG) for each. In the proposed CBRO, the RO process is relied on the HMAGs to reduce the handoff latency while achieving a fast recovery of the optimized path after handoff. The proposed CBRO is evaluated analytically and compared with the basic PMIP and the current RO schemes. The obtained numerical results have shown that the proposed CBRO outperforms all other schemes in terms of signaling cost required to recover the RO status after handoff and the total cost performance metrics. 相似文献