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1.
The multi-orientation occurs frequently in ancient handwritten documents, where the writers try to update a document by adding some annotations in the margins. Due to the margin narrowness, this gives rise to lines in different directions and orientations. Document recognition needs to find the lines everywhere they are written whatever their orientation. This is why we propose in this paper a new approach allowing us to extract the multi-oriented lines in scanned documents. Because of the multi-orientation of lines and their dispersion in the page, we use an image meshing allowing us to progressively and locally determine the lines. Once the meshing is established, the orientation is determined using the Wigner–Ville distribution on the projection histogram profile. This local orientation is then enlarged to limit the orientation in the neighborhood. Afterward, the text lines are extracted locally in each zone basing on the follow-up of the orientation lines and the proximity of connected components. Finally, the connected components that overlap and touch in adjacent lines are separated. The morphology analysis of the terminal letters of Arabic words is here considered. The proposed approach has been experimented on 100 documents reaching an accuracy of about 98.6%.  相似文献   
2.
Opportunistic networking enables users to communicate in an environment where connectivity is intermittent or unstable. However, such networking scheme assumes that mobile nodes voluntary cooperate, which cannot be guaranteed. Some nodes can simply exhibit selfish behavior and thus diminish the effectiveness of the approach. In this paper, a game scenario is formulated in which the nodes try to convince each other to participate in packets forwarding. Each node is considered as a player in this game. When a node comes in the communication range of another, a bargaining game starts between them as part of the message forwarding process. Both players try to have a mutual agreement on a price for message forwarding. We present a new incentive mechanism called evolutionary bargaining‐based incentive scheme (EBIS) to motivate selfish nodes to cooperate in data forwarding. In EBIS, a node negotiates with other nodes to obtain an agreeable amount of credit for its forwarding service. Nodes apply a sequential bargaining game and then adapt their strategies using an evolutionary model to maximize the probability of reaching an agreement. Unlike classical bargaining games, nodes in our model are boundedly rational. In addition, we use the evolutionary stable strategy (ESS) concept to determine the adaptive strategies for the nodes. The comparison of EBIS with a benchmarked model demonstrates that EBIS performs better in terms of packet delivery ratio and average latency.  相似文献   
3.
This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks (WLANs) operating at millimeter-wave frequencies. To obtain realistic simulation results, a six-port model based on the measurement results of a fabricated V-band hybrid coupler, the core component, is used. A frequency-division multiplexing scheme is used by introducing four quadrature phase-shift keying (QPSK) channels in the wireless communication link. The data rate achieved is about 4 Gbit/s. The operating frequency is in the 60-64 GHz unlicensed band. Bit error rate (BER) results are presented, and a comparison is made between single-carrier and multicarrier architectures. The proposed wireless system can be considered an efficient candidate for millimeter-wave communication systems operating at quasi-optical data rates.  相似文献   
4.
5.
Many factors contribute to the planning process of power systems. In the context of expansion planning, focus is paid to selection criteria that enable the optimization of related factors that will result in the best performance. This is described as meeting demand whilst reducing costs and maintaining minimal risk in operation. In this paper, different criteria used in the planning of power system expansion studies are investigated with the objective of identifying their impact on the expansion plan. The results of these criteria on the expansion study of the Jordanian power system are presented. Results show good correspondence to the actual adopted solutions. The spinning reserve is the most influential planning criterion on the overall system expansion cost. This is followed by the peak load changes, and the forced outage rate of the candidate units used for capacity additions to meet future expected demand. Finally, the loss of load expectation and cost of energy not served have the least effect on the overall system expansion cost. These results highlight the importance to be placed on performing sensitivity analyses to determine the most cost effective and acceptable expansion plan of the electric power system. There is a need to continually update the planning criteria to cater for changes and developments in the power system and the economic situation. Finally, the methodology of this study can be generalized to other power systems.  相似文献   
6.
ABSTRACT

During the past few years the city of Ar-Riyadh, the capital of Saudi Arabia, has seen a significant increase in urbanization, from a gross residential area of 8,500 ha in 1980 to 62,712 ha in 1990. This 638 per cent increase in urbanization, accompanied by a 91 per cent increase in population (from 850,000 to 1,622,000), has led to a great increase in water consumption that has reached 620 l/cap/day. Most of this water is imported into the Ar-Riyadh environment, but the capability of that environment to dispose of the excess water or wastewater by means of infiltration or evaporation is limited. Consequently the city has begun to experience a rise in the groundwater level that is causing a variety of problems for its citizens.

This paper outlines the methodologies and discusses the results from a field study of water losses from the municipal wet infrastructures in six selected areas of Ar-Riyadh that included the potable water the sanitary sewer and the storm drainage networks. More emphasis was put on the field identification of leakage from the potable water network that approached 16 per cent of the water fed into the areas. Thus Ar-Riyadh compares well with other cities around the world where leakage has been reported to be in the range between 5 and 50 per cent. Losses from the sanitary and storm drainage systems were 7 and 4.5 per cent respectively. Besides the impacts on buildings and infrastructure services, the cost of potable water lost by leakage on its own, estimated at a minimum value of US$50 million per year is a considerable economic loss.  相似文献   
7.
This article demonstrates an approach for quantifying leakage and pinpointing the location of leaks in water networks. It presents the methodology and discusses the results of an experimental field study that was undertaken in three areas of Riyadh, Saudi Arabia. The experience from this study indicates that the most accurate method for determining leakage rates is by direct measurement of net night flow. In the alternative, commonly‐used method, the net night flow is computed by reducing the minimum night flow by an assumed water consumption for properties at night. This is inappropriate for use in water networks like that of Riyadh, where the practice of water storage at consumers’ premises is a predominant feature of the water supply system.  相似文献   
8.
In a system composed of a photovoltaic (PV) cell, a converter and a resistive load, the Maximum Power Point Tracking (MPPT) techniques are applied at the output of the PV panel and not at the level of the load. In this study, the considered load is a battery at different States Of Charge (SOC) that is charged by the PV panel. The power consumed by the battery is related to its SOC. Consequently, an empty battery consumes more current than a charged one. At full state of charge, the battery does not call for more energy and thus it is not rewarding to extract more power from the PV panel.Besides, in a stand-alone photovoltaic system, the size of the PV panel and the battery should be respected. Thus, the PV current at different irradiances should be compatible with the charging current required to charge the battery at different SOC. A critical situation occurs at high irradiance when the PV panel delivers a high current at Maximum Power Point (MPP) that exceeds the tolerated charging current. The current reaches the top limit when the battery is totally empty, caused by the big difference in potential between the converter output and the battery voltages. In this case, the battery starts to gas when attempts are made to charge it faster than it can absorb the energy. On the other hand, in a fully charged battery, the difference in potential between the converter and the battery is zero. In this case, there is no need to track the MPP.In this study, we will focus on the load type and suggest new methods to reach the MPP depending on the load state. In the proposed designs, the components of the stand-alone system are protected even if they are not well sized. In addition, we will focus on the development of the PV array mathematical model. The results achieved with the system, as well as the experimental results of a laboratory prototype, will be given.  相似文献   
9.
Medium-term load forecasting is an important stage in electric power system planning and operation. It is used in maintenance scheduling, and to plan for outages and major works in the power system. A new technique is proposed which uses hourly loads of successive years to predict hourly loads and peak load for the next selected time span. The proposed method implements a new combination of some existing and well established techniques. This is done by first filtering out the load trend, then applying the SVD (singular value decomposition) technique to de-noise the resulting signal. Hourly load is thus divided to three main components: a) a load trend-following component, b) a random component, and c) a de-noised component. Results of applying the technique to the Jordanian power system showed that good forecasting accuracies are attained. In addition, the proposed method outperforms the traditional exponential curve fitting method. The peak load error was found to be less than 5% using the proposed methodology. It was also found that a lag period of 4 years suits the load forecasting purposes of the Jordanian power system. The proposed method is generic and can be implemented to the hourly loads of any power system.  相似文献   
10.
In this article, present and future energy consumption, electricity demand, potential of renewable energy sources and national energy policy in Jordan are presented. The related environmental impacts are discussed from the sustainable development point of view, including the future role of renewable energy sources. Jordan is a net energy importing country, with almost 96% of its annual needs relying on imported crude oil and refined products from neighboring Arab countries. Due to increasing fossil fuel combustion to meet growing national energy demand, especially electricity generation, air pollution is becoming an important issue in urban areas. Profound cuts in current emission rates, including carbon dioxide, are possible at a bearable cost, and that the government must now invest in low carbon options because of the long lead in time of some technologies. A great deal more could be done to improve energy efficiency, and new and renewable energy schemes should be advocated on different levels. To achieve this, all obstacles including institutional barriers to investment in renewable technologies and national energy plan need to be addressed urgently. Thus, the government is invited to create a Sustainable Energy Unit, which will coordinate government cross-departmental thinking and provide adequate information to the public and to private investors.  相似文献   
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