In this paper, a temporal meta database for three-dimensional (3D) objects whose properties and relationships are supported
by valid time is introduced. Based on our proposed temporal object-oriented conceptual schema model, a conceptual schema of
the temporal meta database can be generated from a 3D graphical data source and other particular application requirements.
Based on our proposed temporal object relational data model with attribute timestamping, logical schemas of the temporal meta
database can be systematically and automatically generated from the conceptual schema. From the temporal meta database, non-temporal/temporal
metadata about temporal 3D objects are available for temporal information system users. Convenient access using database languages
such as SQL can be performed. Queries over 3D objects using a temporal object relational SQL are demonstrated. 相似文献
This paper presents a multiresolution topology optimization (MTOP) scheme to obtain high resolution designs with relatively
low computational cost. We employ three distinct discretization levels for the topology optimization procedure: the displacement mesh (or finite element mesh) to perform the analysis, the design variable mesh to perform the optimization, and the density mesh (or density element mesh) to represent material distribution and compute the stiffness matrices. We employ a coarser discretization
for finite elements and finer discretization for both density elements and design variables. A projection scheme is employed
to compute the element densities from design variables and control the length scale of the material density. We demonstrate
via various two- and three-dimensional numerical examples that the resolution of the design can be significantly improved
without refining the finite element mesh. 相似文献
A novel fiber-optic localized plasma resonance (FO-LPR) sensor composed of a U-shape optical fiber was proposed and demonstrated
in this study. The U-shape optical fiber was fabricated by a femtosecond laser micromachining system. The dimensions of the
U-shape zone were 100 μm in depth measured from the surface of the polymer jacket layer, 80 μm in width in the jacket layer,
60 μm in width in the cladding layer. The total length is 5 mm. After laser annealing treatment, the average surface roughness
was 205.8 nm as determined by Atom Force Microscope (AFM). The exposed surface of the U-shape fiber was modified with self-assembled
gold nanoparticles to produce the FO-LPR sensor. The response of the sensor shows that the signal increases linearly with
increasing refractive index. The sensor resolution of the sensor was determined to be 1.06 × 10−3 RIU. 相似文献
Flood control operation (FCO) of a reservoir is a complex optimization problem with a large number of constraints. With the rapid development of optimization techniques in recent years, more and more research efforts have been devoted to optimizing FCO problems. However, for solving large-scale reservoir group optimization problem, this is still a challenging task. In this work, a reservoir group FCO model is established with minimum flood volume stored in each reservoir and minimum peak flow of downstream control point during the dispatch process. At the same time, a flood forecast model for FCO of a reservoir group is developed by coupling Yin-Yang firefly algorithm (YYFA) with ε constrained method. As a case study, the proposed model is applied to a three-reservoir flood control system in Luanhe River Basin consisting of reservoirs, river channels, and downstream control points. Results show that optimal operation of three reservoirs systems can efficiently reduce the occupied storage capacity for flood control and flood peaks at downstream control point of the basin. The proposed method can be extended to FCO of other reservoir groups with similar conditions.
We study the following energy-efficient scheduling problem. We are given a set of n jobs which have to be scheduled by a single processor whose speed can be varied dynamically. Each job \(J_j\) is characterized by a processing requirement (work) \(p_j\), a release date \(r_j\), and a deadline \(d_j\). We are also given a budget of energy E which must not be exceeded and our objective is to maximize the throughput (i.e., the number of jobs which are completed on time). We show that the problem can be solved optimally via dynamic programming in \(O(n^4 \log n \log P)\) time when all jobs have the same release date, where P is the sum of the processing requirements of the jobs. For the more general case with agreeable deadlines where the jobs can be ordered so that, for every \(i < j\), it holds that \(r_i \le r_j\) and \(d_i \le d_j\), we propose an optimal dynamic programming algorithm which runs in \(O(n^6 \log n \log P)\) time. In addition, we consider the weighted case where every job \(J_j\) is also associated with a weight \(w_j\) and we are interested in maximizing the weighted throughput (i.e., the total weight of the jobs which are completed on time). For this case, we show that the problem becomes \(\mathcal{NP}\)-hard in the ordinary sense even when all jobs have the same release date and we propose a pseudo-polynomial time algorithm for agreeable instances. 相似文献
Growing self-organizing map (GSOM) has been introduced as an improvement to the self-organizing map (SOM) algorithm in clustering
and knowledge discovery. Unlike the traditional SOM, GSOM has a dynamic structure which allows nodes to grow reflecting the
knowledge discovered from the input data as learning progresses. The spread factor parameter (SF) in GSOM can be utilized
to control the spread of the map, thus giving an analyst a flexibility to examine the clusters at different granularities.
Although GSOM has been applied in various areas and has been proven effective in knowledge discovery tasks, no comprehensive
study has been done on the effect of the spread factor parameter value to the cluster formation and separation. Therefore,
the aim of this paper is to investigate the effect of the spread factor value towards cluster separation in the GSOM. We used
simple k-means algorithm as a method to identify clusters in the GSOM. By using Davies–Bouldin index, clusters formed by different
values of spread factor are obtained and the resulting clusters are analyzed. In this work, we show that clusters can be more
separated when the spread factor value is increased. Hierarchical clusters can then be constructed by mapping the GSOM clusters
at different spread factor values. 相似文献
Knowledge of the wetting characteristic of mineral surfaces is paramount in enhancing the efficiency of separation of valuable minerals from gangue using froth flotation. The contact angle value is a useful indicator providing the hydrophobic characteristic of the solid mineral surfaces due to a close relationship between this parameter and the floatability of minerals.In this paper, techniques for contact angle measurements and their applicability on mineral surfaces are reviewed. Two main groups of techniques for contact angle measurements are available; one group is applicable to flat and smooth surfaces while the other one has been especially developed for non-ideal surfaces or particles. Capillary penetration methods have been found to be more applicable than the other methods cited in measuring contact angles on real mineral surfaces. The major challenge with this technique is the modification required to overcome the difficulties in the experimental packing technique needed, and more importantly, to obtain the receding contact angle values. The coupling of accurate contact angle measurements with real (batch) flotation data would seem to be area which has had limited attention. 相似文献
Electricité de France (EDF), the French national electricity company, is operating 54 standardised pressurised water reactors. This about 500 reactor-years experience in nuclear stations operation and maintenance area has allowed EDF to develop its own strategy for monitoring of age-related degradations of NPP systems and components relevant for plant safety and reliability. After more than fifteen years of experience in regulatory transient data collection and seven years of successful fatigue monitoring prototypes experimentation, EDF decided to design a new system called SYSFAC (acronym for SYstème de Surveillance en FAtigue de la Chaudière) devoted to transient logging and thermal fatigue monitoring of the reactor coolant pressure boundary. The system is fully automatic and directly connected to the on-site data acquisition network without any complementary instrumentation. A functional transient detection module and a mechanical transient detection module are in charge of the general transient data collection. A fatigue monitoring module is aimed towards a precise surveillance of five specific zones particularly sensible to thermal fatigue. After a first step of preliminary studies, the industrial phase of the SYSFAC project is currently going on, with hardware and software tests and implementation. The first SYSFAC system will be delivered to the pilot power plant by the beginning of 1996. The extension to all EDF’s nuclear 900 MW is planned after one more year of feedback experience. 相似文献
The influences of the particle size reduction and physicochemical changes by micron technology on the intestinal health-improvement ability of a promising carrot insoluble fibre was investigated. The feeding of the micronized fibres (10.3–20.9 μm), especially that prepared by the high-pressure micronization, could significantly (p < 0.05) improve some caecal and faecal parameters in the intestinal lumen by decreasing caecal ammonia concentration (−25.5%), increasing faecal output (137%) and moisture content (142%), and also reducing the activities of undesired β-d-glucosidase (−42.1%) and β-d-glucuronidase (−68.9%) in faeces. The relationships between the physicochemical properties and physiological functions of the micronized fibres have been discussed. The results also demonstrated that both the particle size and way of treatment were important factors affecting the physicochemical properties and physiological functions of fibres, and the consumption of micronized fibre at 5% level might exert a favourable effect on improving intestinal health. 相似文献
We present a novel differential space-time modulation (DSTM) scheme that is single-symbol decodable and can provide full transmit diversity. It is the first known single-symbol-decodable DSTM scheme not based on orthogonal STBC (O-STBC), and it is constructed based on the recently proposed minimum-decoding-complexity quasi-orthogonal space-time block code (MDC-QOSTBC). We derive the code design criteria and present systematic methodology to find the solution sets. The proposed DSTM scheme can provide higher code rate than DSTM schemes based on O-STBC. Its decoding complexity is also considerably lower than DSTM schemes based on Sp(2) and double-symbol-decodable QO-STBC, with negligible or slight trade-off in decoding error probability performance 相似文献