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1.
Encryption is one of the fundamental technologies that is used in the security of multimedia data. Unlike ordinary computer applications, multimedia applications generate large amount of data that has to be processed in real time. This work investigates the problem of efficient multimedia data encryption. A scheme known as the Randomized Huffman Table scheme was recently proposed to achieve encryption along with compression. Though this scheme has several advantages it cannot overcome the chosen plaintext attack. An enhancement of this Huffman scheme is proposed in this work which essentially overcomes the attack and improves the security. The proposed encryption approach consists of two modules. The first module is the Randomized Huffman Table module, the output of which is fed to the second XOR module to enhance the performance. Security analysis shows that the proposed scheme can withstand the chosen plaintext attack. The efficiency and security of the proposed scheme makes it an ideal choice for real time secure multimedia applications.  相似文献   
2.
We present an end‐stage renal disease patient on dialysis with fever. The primary source was right internal jugular vein catheter which had metastatic infections in the body probably via an arteriovenous communication in a cavity in left lung. Patient had right psoas muscle abscess and a left kidney abscess. An 18F‐fluorodeoxyglucose‐positron emission spectroscopy scan was done to find out left kidney abscess. A search of literature did not reveal many patients of psoas abscess secondary to infection of hemodialysis access.  相似文献   
3.
Emissions from harbor-craft significantly affect air quality in populated regions near ports and inland waterways. This research measured regulated and unregulated emissions from an in-use EPA Tier 2 marine propulsion engine on a ferry operating in a bay following standard methods. A special effort was made to monitor continuously both the total Particulate Mass (PM) mass emissions and the real-time Particle Size Distribution (PSD). The engine was operated following the loads in ISO 8178-4 E3 cycle for comparison with the certification standards and across biodiesel blends. Real-time measurements were also made during a typical cruise in the bay. Results showed the in-use nitrogen oxide (NOx) and PM(2.5) emission factors were within the not to exceed standard for Tier 2 marine engines. Comparing across fuels we observed the following: a) no statistically significant change in NO(x) emissions with biodiesel blends (B20, B50); b) ~ 16% and ~ 25% reduction of PM(2.5) mass emissions with B20 and B50 respectively; c) a larger organic carbon (OC) to elemental carbon (EC) ratio and organic mass (OM) to OC ratio with B50 compared to B20 and B0; d) a significant number of ultrafine nuclei and a smaller mass mean diameter with increasing blend-levels of biodiesel. The real-time monitoring of gaseous and particulate emissions during a typical cruise in the San Francisco Bay (in-use cycle) revealed important effects of ocean/bay currents on emissions: NO(x) and CO(2) increased 3-fold; PM(2.5) mass increased 6-fold; and ultrafine particles disappeared due to the effect of bay currents. This finding has implications on the use of certification values instead of actual in-use emission values when developing inventories. Emission factors for some volatile organic compounds (VOCs), carbonyls, and poly aromatic hydrocarbons (PAHs) are reported as supplemental data.  相似文献   
4.
Bentonite, a commercially available clay mineral, can be used for increasing the water holding capacity of the soil and as a sealant material. Laboratory studies were conducted with the amended soil using bentonite as an ameliorant. The mixtures were prepared with the additives on a volume basis. The chemical, physical, and hydraulic properties of the bentonite and native red soil (alfisol) mixtures were determined. Available water contents improved significantly in soil-bentonite mixtures. The pH of bentonite and soil mixtures increased from neutral value to alkalinity with the increasing proportion of bentonite in the mixtures. The same trend was also observed for cation exchange capacity. Bulk density increased from a 1:50 mixture to a 1:5 mixture and afterward decreased with the increase in the proportion of bentonite. Plastic and flow limits of the mixtures increased with the increase in bentonite proportion. Soil erodibility (dispersion ratio) as well as surface cracking increased with the addition of bentonite to native soil.  相似文献   
5.
Secure and reliable group communication is an active area of research. Its popularity is fuelled by the growing importance of group-oriented and collaborative applications. The central research challenge is secure and efficient group key management. The present paper is based on the huddle hierarchy based secure multicast group key management scheme using the most popular absolute encoder output type code named gray code. The focus is of twofolds. The first fold deals with the reduction of computation complexity which is achieved in this protocol by performing fewer multiplication operations during the key updating process. To optimize the number of multiplication operations, the fast Fourier transform, divide and conquer approach for multiplication of polynomial representation of integers, is used in this proposed work. The second fold aims at reducing the amount of information stored in the Group Center and group members while performing the update operation in the key content. Comparative analysis to illustrate the performance of various key distribution protocols is shown in this paper and it has been observed that this proposed algorithm reduces the computation and storage complexity significantly.  相似文献   
6.
7.
The cloud computing environment is a real‐time communication network that involves a large number of systems connected in a distributed fashion, for which resources are available on demand. In recent years, due to the enormous growth of data and information, data maintenance tasks involve a major effort in information technology (IT) industries. So, IT industries are concentrating on the cloud computing environment in order to maintain their data and manage their resources. Owing to the increase in the number of data centres, which have an impact on electrical energy cost, peak power dissipation, cooling and carbon emission, power‐conservation‐based resource management is essential. A best‐fit heuristic job placement algorithm is proposed in this paper in order to increase the job allocation percentage, a worst‐fit heuristic virtual machine (VM) placement algorithm is also proposed in order to place the VMs over the physical machines (PMs) thereby reducing the number of the latter allotted, and a server consolidation algorithm is proposed in order to improve power conservation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
8.
Hydrogen remains an attractive alternative fuel to petroleum and a number of investigators claim that adding hydrogen to the air intake manifold of a diesel engine will reduce criteria emissions and diesel fuel consumption. Such claims are appealing when trying to simultaneously reduce petroleum consumption, greenhouse gases and criteria pollutants. The goal of this research was to measure the change in criteria emissions (CO, NOx, and PM2.5) and greenhouse gases such as carbon dioxide (CO2), using standard test methods for a wide range of hydrogen addition rates. A two-stroke Detroit Diesel Corporation 12V-71TI marine diesel engine was mounted on an engine dynamometer and tested at three out of the four loads specified in the ISO 8178-4 E3 emission test cycle and at idle. The engine operated on CARB ultra-low sulfur #2 diesel with hydrogen added at flow rates of 0, 22 and 220 SLPM.  相似文献   
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10.
Denatured lysozyme was refolded by a dilution method. The refolding yield depended greatly on the lysozyme concentration in the refolding mixture. When the concentration of denatured lysozyme was 0.02 g/L, the refolding yield was as high as 60%. However, when the concentration of denatured lysozyme was 0.2 g/L, the refolding yield was as low as 10% due to the formation of aggregates. To prevent the formation of aggregates and to increase the refolding yield at a low cost, inexpensive additives were screened. The addition of acetone, acetoamide, or urea derivatives was very effective for improving the refolding yield. To clarify why the addition of acetoamide in the refolding mixture improved the refolding yield at the high lysozyme concentration, the time courses of the concentration and the average diameter of the aggregates in the refolding mixture were monitored by the dynamic light scattering method. The experimental results showed that acetoamide played a role in preventing the formation and growth of aggregates and secondary aggregation between the lysozyme aggregates.  相似文献   
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