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291.
Engin Demir 《Information Sciences》2010,180(14):2743-2762
Get-Successors (GS) which retrieves all successors of a junction is a kernel operation used to facilitate aggregate computations in road network queries. Efficient implementation of the GS operation is crucial since the disk access cost of this operation constitutes a considerable portion of the total query processing cost. Firstly, we propose a new successor retrieval operation Get-Unevaluated-Successors (GUS), which retrieves only the unevaluated successors of a given junction. The GUS operation is an efficient implementation of the GS operation, where the candidate successors to be retrieved are pruned according to the properties and state of the algorithm. Secondly, we propose a hypergraph-based model for clustering successively retrieved junctions by the GUS operations to the same pages. The proposed model utilizes query logs to correctly capture the disk access cost of GUS operations. The proposed GUS operation and associated clustering model are evaluated for two different instances of GUS operations which typically arise in Dijkstra’s single source shortest path algorithm and incremental network expansion framework. Our simulation results show that the proposed successor retrieval operation together with the proposed clustering hypergraph model is quite effective in reducing the number of disk accesses in query processing. 相似文献
292.
Onur Karasakal Mujde Guzelkaya Ibrahim Eksin Engin Yesil Tufan Kumbasar 《Engineering Applications of Artificial Intelligence》2013,26(1):184-197
In this study, an on-line tuning method is proposed for fuzzy PID controllers via rule weighing. The rule weighing mechanism is a fuzzy rule base with two inputs namely; “error” and “normalized acceleration”. Here, the normalized acceleration provides relative information on the fastness or slowness of the system response. In deriving the fuzzy rules of the weighing mechanism, the transient phase of the unit step response of the closed loop system is to be analyzed. For this purpose, this response is assumed to be divided into certain regions, depending on the number of membership functions defined for the error input of the fuzzy logic controller. Then, the relative importance or influence of the fired fuzzy rules is determined for each region of the transient phase of the unit step response of the closed loop system. The output of the fuzzy rule weighing mechanism is charged as the tuning variable of the rule weights; and, in this manner, an on-line self-tuning rule weight assignment is accomplished. The effectiveness of the proposed on-line weight adjustment method is demonstrated on linear and non-linear systems by simulations. Moreover, a real time application of this new method is accomplished on a pH neutralization process. 相似文献
293.
Ayca Yildiz Pekoz Meryem Sedef Erdal Alper Okyar Meltem Ocak Fatma Tekeli Engin Kaptan 《Drug development and industrial pharmacy》2016,42(6):916-925
AbstractDimenhydrinate (DMH)-loaded buccal bioadhesive films for the prevention and treatment of motion sickness were prepared and optimized. This study examines the rate of drug release from the films for prolonged periods of time to reduce or limit the frequency of DMH administration. Based on preliminary studies using various polymers and concentrations, hydroxyethylcellulose (2.5, 3.0, and 3.2%), and xanthan gum (2.8%) were chosen as matrix polymers. The films were analyzed with respect to their mechanical, physicochemical, bioadhesive, swelling, and in-vitro release properties. In in-vivo pharmacokinetic studies, xanthan gum-based DMH buccal film was associated with significantly increased DMH plasma levels between 1 h and 5 h after DMH dosing when compared with an oral drug solution. The area under the curve AUC0–7 h value of the mucoadhesive buccal film was two-fold higher than the oral DMH solution. Histological analysis revealed that DMH films cause mild morphological and inflammatory changes in rabbit buccal mucosa. The DMH buccal film is effective for approximately 7 h, thus representing an option for single-dose antiemetic therapy. This dosage regimen could be particularly beneficial for chain travelers who travel for long periods of time. 相似文献
294.
Telecommunication Systems - According to International Mobile Telecommunication’s requirements for 2020, next generation cellular networks such as 5G need to meet certain Key Performance... 相似文献
295.
This paper proposes a simple diagnostic method to determine the number of open and short circuited PV modules in a string of a PV system by taking into account the economical factor, such as minimum number of sensors. The diagnostic algorithm has as inputs the irradiance level, the PV modules temperature, the number of PV modules present in the string analyzed and its output power. So, just temperature and irradiance sensors, as well as a power meter by string are needed in the monitoring system forming part of the fault diagnostic system. The proposed fault detection method has been successfully validated experimentally. 相似文献
296.
Cengiz Kahraman Orhan Engin
zgür Kabak hsan Kaya 《Engineering Applications of Artificial Intelligence》2009,22(6):832-841
Outsourcing refers to a company that contracts with another company to provide services that might otherwise be performed by in-house employees. Information system (IS) outsourcing policies define the criteria that organizations utilize to decide upon the scope and degree of reliance of their IS capabilities upon external sources. IS outsourcing is an innovative organizational tool for IS management in both private and public sector organizations. In this paper, an interactive group decision-making methodology is proposed to select/rank IS providers under multiple criteria. A measure for the consensus level of the group preferences is developed to satisfy an acceptable level of group agreement and reliability. The Spearman coefficients for both the aggregated rank order and each DM's rank order have also been calculated. The group and the individual evaluations are gathered through a fuzzy TOPSIS approach. The proposed methodology is applied in the largest office furniture manufacturer in Konya-Turkey. Eight alternative IS providers are evaluated based on seven criteria by five decision makers. Sensitivity analyses are also provided to see the effects of parameter changes on the final decision. 相似文献
297.
Dielissen J. Nur Engin Sawitzki S. van Berkel K. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2008,55(3):284-288
One of the key features of a modern mobile terminal is the simultaneous support of multiple/different transmission standards. Most of these standards include forward error correction decoding functionality. In this overview paper we review the possibilities for combinations of common decoder families (Reed-Solomon, Viterbi, Turbo and low-density parity check) within one hardware platform. We show, that although specific combinations may result in silicon area savings, in general case the reuse possibilities are limited to much less than 20% of the overall decoder area. 相似文献
298.
Inserted cutters are widely used in roughing and finishing of parts. The insert geometry and distribution of inserts on the cutter body vary significantly in industry depending on the application. This paper presents a generalized mathematical model of inserted cutters for the purpose of predicting cutting forces, vibrations, dimensional surface finish and stability lobes in milling. In this paper, the edge geometry is defined in the local coordinate system of each insert, and placed and oriented on the cutter body using the cutter's global coordinate system. The cutting edge locations are defined mathematically, and used in predicting the chip thickness distribution along the cutting zone. Each insert may have a different geometry, such as rectangular, convex triangular or a mathematically definable edge. Each insert can be placed on the cutter body mathematically by providing the coordinates of the insert center with respect to the cutter body center. The inserts can be oriented by rotating them around the cutter body, thus each insert may be assigned to have different lead and axial rake angles. By solving the mechanics and dynamics of cutting at each edge point, and integrating them over the contact zone, it is shown that the milling process can be predicted for any inserted cutter. A sample of inserted cutter modeling and analysis examples are provided with experimental verifications. 相似文献
299.
300.
Hikmet Sayilkan Şadiye Şsener Engin Şener Ertuğrul Arpaç 《Journal of Materials Science》1999,34(21):5325-5330
In this work, (a) hydrolyses of Ti(OEt)4 and Zr(OPrn)4 with different amounts of water, (b) complexation of the same alkoxides with varying amounts of methacrylic acid, (c) hydrolysis of the complexation products with varying amounts of water, and subsequent polymerization, (d) adsorption capacities of the hydrolysis products (a and c) for aqueous aniline and phenol, were investigated. It was found that condensation reactions which follows the hydrolysis reactions, were alcohol condensations. The products were characterized in detail. Adsorption of aniline and phenol were compared for thermally conditioned powder of the products and some powders coated with 3-glycidyloxypropyltrimethoxysilane. It was observed that the extent of adsorption was influenced significantly by the temperature at which the adsorbents were calcinated by the coating of their surfaces. 相似文献