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排序方式: 共有1258条查询结果,搜索用时 15 毫秒
41.
Pradeep Kumar Gupta Dilip Sharma Shyam Lal Soni Rahul Goyal Dheeraj Kishor Johar 《Clean Technologies and Environmental Policy》2017,19(3):883-895
Old engines (Euro III or earlier) produce more emissions, and it will be difficult to entirely stop their usage especially in developing and under-developed nations; hence, it is desired that appropriate emission reduction technologies are tested on such engines to analyze their feasibility and economical acceptability. While most such studies have been conducted on constant speed stationary engines and modern engines, this study tried to analyze the effectiveness of an uncoated wall-flow type ceramic diesel particulate filter on a Euro-I, water-cooled, direct injection, variable speed, compression ignition engine in a laboratory set-up in India. Also, this study focused on diesel particulate filter regeneration by two methods: active regeneration by diesel injection in the particulate filter using an electronic control unit and off-board regeneration by taking out and heating the diesel particulate filter in an electrical resistance furnace at 650 °C for 10 h. The results, in the form of smoke emission, NOx emission and engine performance, obtained using both the regeneration methods were analyzed, and conclusions were drawn. It was found that using diesel particulate filter, particulate matter emissions (smoke) were almost entirely eliminated. It was also found that off-board regeneration had numerous advantages compared to active regeneration. Since a furnace would be needed for off-board regeneration, an exchange process for diesel particulate filter is suggested. 相似文献
42.
Rahul S. Kalhapure Pradeep Bolla Delfina C. Dominguez Amit Dahal Sai H.S. Boddu Jwala Renukuntla 《IET nanobiotechnology / IET》2018,12(6):836
Silver (Ag) complexes of drugs and their nanosystems have great potential as antibacterials. Recently, an Ag complex of furosemide (Ag–FSE) has shown to be a promising antimicrobial. However, poor solubility of Ag–FSE could hamper its introduction into clinics. Therefore, the authors developed a nanosuspension of Ag–FSE (Ag–FSE_NS) for its solubility and antibacterial activity enhancement. The aim of this study was to introduce a novel nanoantibiotic with enhanced antibacterial efficacy. Ag–FSE_NS was prepared by precipitation–ultrasonication technique. Size, polydispersity index (PI) and zeta potential (ZP) of prepared Ag–FSE_NS were measured by dynamic light scattering, whereas surface morphology was determined using scanning electron microscopy (SEM). In vitro antibacterial activity was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa using broth microdilution method. Size, PI and ZP of optimised Ag–FSE_NS1 were 191.2 ± 19.34 nm, 0.465 ± 0.059 and −55.7 ± 8.18 mV, respectively. SEM revealed that Ag–FSE_NS1 particles were rod or needle‐like with smooth surfaces. Saturation solubility of Ag–FSE in NS increased eight‐fold than pure Ag–FSE. Ag–FSE_NS1 exhibited two‐fold and eight‐fold enhancements in activity against E. coli and S. aureus, respectively. The results obtained showed that developed Ag–FSE_NS1 holds a promise as a topical antibacterial.Inspec keywords: nanomedicine, nanofabrication, light scattering, surface morphology, silver, particle size, solubility, suspensions, scanning electron microscopy, electrokinetic effects, drugs, biomedical materials, antibacterial activity, microorganisms, nanoparticles, drug delivery systems, transmission electron microscopyOther keywords: saturation solubility, topical antibacterial, size 171.86 nm to 210.54 nm, voltage ‐47.52 mV to ‐63.88 mV, Ag, broth microdilution method, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, SEM, scanning electron microscopy, surface morphology, dynamic light scattering, particle size, polydispersity index, precipitation–ultrasonication technique, nanoantibiotic, nanosuspension, furosemide, nanosystems, drugs, Ag–FSE_NS preparation, in vitro antibacterial activity, pure Ag–FSE, Ag–FSE_NS1 particles, optimised Ag–FSE_NS1, zeta potential, enhanced antibacterial efficacy, antibacterials 相似文献
43.
Yiling Chen Stanko Dimitrov Rahul Sami Daniel M. Reeves David M. Pennock Robin D. Hanson Lance Fortnow Rica Gonen 《Algorithmica》2010,58(4):930-969
We study the equilibrium behavior of informed traders interacting with market scoring rule (MSR) market makers. One attractive feature of MSR is that it is myopically incentive compatible: it is optimal for traders to report their true beliefs about the likelihood of an event outcome provided that they ignore
the impact of their reports on the profit they might garner from future trades. In this paper, we analyze non-myopic strategies
and examine what information structures lead to truthful betting by traders. Specifically, we analyze the behavior of risk-neutral
traders with incomplete information playing in a dynamic game. We consider finite-stage and infinite-stage game models. For
each model, we study the logarithmic market scoring rule (LMSR) with two different information structures: conditionally independent
signals and (unconditionally) independent signals. In the finite-stage model, when signals of traders are independent conditional
on the state of the world, truthful betting is a Perfect Bayesian Equilibrium (PBE). Moreover, it is the unique Weak Perfect
Bayesian Equilibrium (WPBE) of the game. In contrast, when signals of traders are unconditionally independent, truthful betting
is not a WPBE. In the infinite-stage model with unconditionally independent signals, there does not exist an equilibrium in which
all information is revealed in a finite amount of time. We propose a simple discounted market scoring rule that reduces the
opportunity for bluffing strategies. We show that in any WPBE for the infinite-stage market with discounting, the market price
converges to the fully-revealing price, and the rate of convergence can be bounded in terms of the discounting parameter.
When signals are conditionally independent, truthful betting is the unique WPBE for the infinite-stage market with and without
discounting. 相似文献
44.
Fusion of probabilistic A* algorithm and fuzzy inference system for robotic path planning 总被引:1,自引:0,他引:1
Robotic Path planning is one of the most studied problems in the field of robotics. The problem has been solved using numerous
statistical, soft computing and other approaches. In this paper we solve the problem of robotic path planning using a combination
of A* algorithm and Fuzzy Inference. The A* algorithm does the higher level planning by working on a lower detail map. The
algorithm finds the shortest path at the same time generating the result in a finite time. The A* algorithm is used on a probability
based map. The lower level planning is done by the Fuzzy Inference System (FIS). The FIS works on the detailed graph where
the occurrence of obstacles is precisely known. The FIS generates smoother paths catering to the non-holonomic constraints.
The results of A* algorithm serve as a guide for FIS planner. The FIS system was initially generated using heuristic rules.
Once this model was ready, the fuzzy parameters were optimized using a Genetic Algorithm. Three sample problems were created
and the quality of solutions generated by FIS was used as the fitness function of the GA. The GA tried to optimize the distance
from the closest obstacle, total path length and the sharpest turn at any time in the journey of the robot. The resulting
FIS was easily able to plan the path of the robot. We tested the algorithm on various complex and simple paths. All paths
generated were optimal in terms of path length and smoothness. The robot was easily able to escape a variety of obstacles
and reach the goal in an optimal manner. 相似文献
45.
Knowledge of the information goal of users is critical in website design, analyzing the efficacy of such designs, and in ensuring effective user-access to
desired information. Determining the information goal is complex due to the subjective and latent nature of user information
needs. This challenge is further exacerbated in media-rich websites since the semantics of media-based information is context-based
and emergent. A critical step in determining information goals lies in the identification of content pages. These are the pages which contain the information the user seeks. We propose a method to automatically determine the content
pages by taking into account the organization of the web site, the media-based information content, as well as the influence
of a specific user browsing pattern. Given a specific browsing pattern, in our method, putative content pages are identified
as the pages corresponding to the local minima of page-content entropy values. For an (unknown) user information goal this
intuitively corresponds to modeling the progressive transition of the user from pages with generic information to those with
specific information. Experimental investigations on media rich sites demonstrate the effectiveness of the technique and underline
its potential in modeling user information needs and actions in a media-rich web. 相似文献
46.
We introduce the concert (or cafeteria) queueing problem: A finite but large number of customers arrive into a queueing system
that starts service at a specified opening time. Each customer is free to choose her arrival time (before or after opening
time), and is interested in early service completion with minimal wait. These goals are captured by a cost function which
is additive and linear in the waiting time and service completion time, with coefficients that may be class dependent. We
consider a fluid model of this system, which is motivated as the fluid-scale limit of the stochastic system. In the fluid
setting, we explicitly identify the unique Nash-equilibrium arrival profile for each class of customers. Our structural results
imply that, in equilibrium, the arrival rate is increasing up until the closing time where all customers are served. Furthermore,
the waiting queue is maximal at the opening time, and monotonically decreases thereafter. In the simple single class setting,
we show that the price of anarchy (PoA, the efficiency loss relative to the socially optimal solution) is exactly two, while
in the multi-class setting we develop tight upper and lower bounds on the PoA. In addition, we consider several mechanisms
that may be used to reduce the PoA. The proposed model may explain queueing phenomena in diverse settings that involve a pre-assigned
opening time. 相似文献
47.
An interval-based automated optimization of aircraft wing structures subjected to landing loads is discussed in this paper. The interaction between landing gear and flexible airplane structure is considered as a coupled system. The uncertain system parameters are described as interval numbers. The computational aspects of the optimization procedure are illustrated with two examples – symmetric double-wedge airfoil, and supersonic airplane wing. Since, in most cases only the ranges of uncertain parameters are known with their probability distribution functions unknown, the present methodology is expected to be more realistic for the optimum design of aircraft structures under landing loads. 相似文献
48.
Integrated circuits (ICs) are often produced in foundries that lack effective security controls. In these foundries, sophisticated attackers are able to insert malicious Trojan circuits that are easily hidden in the large, complex circuitry that comprises modern ICs. These so-called Trojan circuits are capable of launching attacks directly in hardware, or, more deviously, can facilitate software attacks. Current defense against Trojan circuits consists of statistical detection techniques to find such circuits before product deployment. The fact that statistical detection can result in false negatives raises the obvious questions: can attacks be detected post-deployment, and is secure execution nonetheless possible using chips with undetected Trojan circuits? In this paper we present the Secure Heartbeat And Dual-Encryption (SHADE) architecture, a compiler–hardware solution for detecting and preventing a subset of Trojan circuit attacks in deployed systems. Two layers of hardware encryption are combined with a heartbeat of off-chip accesses to provide a secure execution environment using untrusted hardware. The SHADE system is designed to complement pre-deployment detection techniques and to add a final, last-chance layer of security. 相似文献
49.
Information Systems and e-Business Management - Collaborative filtering (CF) is a popular and widely accepted recommendation technique. CF is an automated form of word-of-mouth communication... 相似文献
50.
In this paper we present a novel technique for easily calibrating multiple casually aligned projectors on spherical domes using a single uncalibrated camera. Using the prior knowledge of the display surface being a dome, we can estimate the camera intrinsic and extrinsic parameters and the projector to display surface correspondences automatically using a set of images. These images include the image of the dome itself and a projected pattern from each projector. Using these correspondences we can register images from the multiple projectors on the dome. Further, we can register displays which are not entirely visible in a single camera view using multiple pan and tilted views of an uncalibrated camera making our method suitable for displays of different size and resolution. We can register images from any arbitrary viewpoint making it appropriate for a single head‐tracked user in a 3D visualization system. Also, we can use several cartographic mapping techniques to register images in a manner that is appropriate for multi‐user visualization. Domes are known to produce a tremendous sense of immersion and presence in visualization systems. Yet, till date, there exists no easy way to register multiple projectors on a dome to create a high‐resolution realistic visualizations. To the best of our knowledge, this is the first method that can achieve accurate geometric registration of multiple projectors on a dome simply and automatically using a single uncalibrated camera. 相似文献