Papers by Keyword: Hierarchical

Abstract: SiO₂ were successfully synthesized by sol–gel process via in-situ modification. The SiO₂ consists of two kinds of co-precursor namely raw material from quartz sand and methyltrimethoxysilane (MTMS) as main SiO₂ source. By introducing SiO₂ with different sizes of particle micro-submicron scale, it was suggested to construct hierarchical structure. The sample was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Atomic Force Microscope (AFM) to analyze crystal structure, morphology of particles, and surface roughness of the samples. In this research, SiO₂ co-precursor from quartz sand were extraction and synthesis to be SiO₂ quartz (SQ) phase and SiO₂ amorphous (SA) phase respectively which is combine with SiO₂ based MTMS by sol–gel process via in-situ modification. Based on the results, it can be concluded that SiO₂ with high purity levels maintains its crystal structure even after in-situ modification, resulting in an increase in particle size to approximately 12-20 μm. SEM images showed that particle was irregular shape due to agglomeration which is SiO₂ based quartz sand stick by SiO₂ based MTMS. AFM showed the surface roughness of MTMS/SQ have a larger roughness than MTMS/SA with Sa 3.3 ± 0.8 nm and Sq 5.0 ± 1.0 nm. The formation of hierarchical structure layers based on SiO₂ has a promising potential for wide applications in various fields such as hydrophobic surface.

Abstract: Data-mining methods using hierarchical and non-hierarchical clustering are proposed, which could help manufacturing engineers determine guidelines for deciding end-milling conditions. We have constructed a novel system that uses clustering techniques and tool catalog data to support the determination of end-milling conditions for different types of recent difficult-to-cut materials. In the present report, we especially focus on the cutting speed to estimate the performance of this system. A comparison with the conditions recommended by famous tool makers in Japan, reveals that our proposed system can be used to determine the cutting speeds for various difficult-to-cut materials. That is, milling experiments using a square end mill under two sets of end-milling conditions (conditions derived from the end-milling condition decision support system and conditions suggested by expert engineers) for difficult-to-cut materials (austenite stainless steel; JIS SUS310) showed that the catalog mining method is effective for deriving guidelines for deciding end-milling conditions at the beginning of the manufacturing stage.

Abstract: To find the optimal path of mobile robots,a novel robot path planning strategy based on hierarchical control fuzzy algorithm has been proposed.The path planning strategy which developed to overcome the collision and avoidance problem in path planning of robot is inspired by fuzzy control concept,in order to achieving a target that making robots to follow a non-collision rapid and accurate path in uncertain environment.Simulation results showed that the strategy using fuzzy algorithm could meet the feasibility and validity demand.

Abstract: In order to make all students choose their own personal practice activities according to their actual needs, an opening hierarchical practice teaching system is designed. The system can provide an abundant, progressive, alternative, developmental practice way for students to choose their practical activities, which is designed through five aspects such as practical course, course contest, students’ scientific research, participating in teachers’ scientific research, enterprise practice. In addition, the system can make students get what they need, do their best, do their respective development, show their own characteristics; it also enables excellence students to surpass themselves, ordinary students to realize their dreams, students with learning difficulties to complete their studies.

Abstract: P2P live streaming is a hot research topic of Internet, but for the defective of system architecture and scheduling policy, P2P streaming applications have poor user experience, such as long start-delay, long play-delay, and low play-continuity and so on. Firstly, based on the analysis of the advantages and disadvantages of previous works, this paper designed and implemented a hierarchical P2P streaming system. The system is composed by three layers: source management servers, region management servers, and peers. The underlying P2P overlay network is organized through Mesh-pull mechanism. We propose a new scheduling strategy to utilize the capacity of the peer. The new adaptive scheduling strategy considers the urgency and scarcity of the data blocks, and selects the appropriate neighbor nodes by monitoring neighbor nodes’ the maximum load. The study of a real-life system provides valuable insights for the future development of P2P live streaming systems.

Abstract: This paper proposed an applied-information technology in hierarchical network security protocols designing model based on public key, the designing of the protocols is to be completed in several layers. Each sub-protocol achieved a sub-goal that it should complete, and provided data interface to a higher sub-protocol. And then merged the sub-protocol of each layer, to complete the protocols designing. In the previous research, the security of the protocol in applied-information technology was always regarded as a whole, which caused the protocols designing to be tremendous complexity. The hierarchical model in applied-information technology simplifies the process of security protocols designing, and make the protocols designing more clear or less cost, the security proof more simpler.

Abstract: Since the energy of wireless sensor nodes is limited, the protocols of wireless sensor network (WSN) we design should care about problems of balancing energy of nodes. After analyzing current algorithms, this paper puts forward an hierarchical and clustering strategy for routing based on Ant Colony Optimization (HC-ACO). The protocol divides the nodes into fixed clusters, each cluster selects a Cluster Header (CH) and switches the CH by its energy and other restrictive conditions. And it adopts ACO to search the optimal path between the CHs and Sink node. The simulation indicates the protocol can balance energy consumption of nodes of network.

Abstract: The hierarchical and ordered porous nanostructured carbons (HOPNCs) have a very wide application in catalysis, adsorption separation, energy storage and other fields. In this paper, the HOPNCs was prepared through a dual-template method and the resole resin as the carbon precursor,followed by the ethanol solvent evaporation induced self-assembly process. The morphology and microstructure of the as-made products were characterized by SEM, XRD, TEM,and physical adsorption instrument. The results showed that the orderliness of mesoporous carbon materials are significantly enhanced while the ratio of P123/F127 was 1/3,a proper low concentration of template and alcohol solution was helpful to the solvent induced selfassembly formed ordered mesoporous structure of nanocarbons.The as-made HOPNCs have large pores of 200 nm or so, mesopores of 8 and 3 nm or so, the pore volume of 0.2527 cm³/g , the BET surface area of 510m²/g.

Abstract: In accordance with the object-oriented design principles, the flight simulation platform of each function is modular and hierarchical. The 1 Pool 2 Pieces 4 Layers software framework is proposed, using VC++ features to abstract all the replaceable modules to the same class, realizing rapid conversion of a variety of aircraft and different tests, to achieve reconfigurable. The realistic flight dynamics model considering wind disturbance is established, and with F-16 model as an example has conducted digital simulation and visual simulation. The results show that the platform has good maneuverability and fidelity, and provides reliable basis for aircraft design.

Abstract: Medical images registration technique is important to the modern clinical medicine. A registration algorithm of medical images is proposed in the paper. The algorithm consists of two part, i.e. the rough registration and the fine registration. In the rough registration procedure, the contour lines of the couple medical images are obtained at first, then they are resampled to obtain fewer contour feature points. The rough registration is accomplished based on the resampled contour lines and the Principal Axes method. In the fine registration procedure, the simplified multiwavelet transform is used to obtain the couple images multiscale information at first, then part of high-frequency coefficients are selected as registration objects. In addition, the selected high-frequency sub-bands are filtered by their mathematical expectation, and hierarchical registration strategy is used in the registration process. The experiment results show that the proposed registration algorithm is an effect method, not only the registrations precision can be held, but also the calculation cost is reduced.