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991.
992.
Sung-Dae Yeo Tae-Il Cho Jong-Un Kim Goo-Man Park Seong-Kweon Kim 《Multimedia Tools and Applications》2017,76(9):11361-11376
Like the concept of free-viewpoint TV (FTV), the audio data should be rendered according to video data. However, on condition that minimum numbers of microphone are used, it is difficult to acquire accurate audio signal for rendering audio data to the image with the choice of view point. Especially, degradation of high frequency components (HFC) happens due to the characteristic of polar pattern for microphone. The degradation of HFC causes imperfection of signal restoration and leads to the degradation of clarity for hearing. In this paper, a compensation method for the degradation of HFC audio signal is proposed for producing an immersive audio effect at realistic media. Our experimental results show that low frequency components (LFC) of audio signal had a little directional degradation in spite of effect of the polar patterns of microphone and the compensation of HFC can be realized with adapting the attenuation inclination of LFC. This research is expected to be helpful for producing an immersive audio effect for a realistic media. 相似文献
993.
A wide variety of tool condition monitoring techniques has been introduced in recent years. Among them, tool force monitoring, tool vibration monitoring and tool acoustics emission monitoring are the three most common indirect tool condition monitoring techniques. Using multiple intelligent sensors, these techniques are able to monitor tool condition with varying degrees of success. This paper presents a novel approach for the estimation of tool wear using the reflectance of cutting chip surface and a back propagation neural network. It postulates that the condition of a tool can be determined using the surface finish and color of a cutting chip. A series of experiments has been carried out. The experimental data obtained was used to train the back propagation neural network. Subsequently, the trained neural network was used to perform tool wear prediction. Results show that the prediction is in good agreement with the flank wear measured experimentally. 相似文献
994.
Although a wide range of Internet telephony applications such as VocalTec's Internet Phone and Microsoft's NetMeeting has
been developed to support real-time voice communication over the Internet, they are predominantly written for the Windows
95/NT platform and are not compatible with other operating systems. Moreover, most of the Internet telephony software is operated
as stand-alone applications and must be downloaded and installed prior to operation. This has caused great inconvenience in
using Internet telephony software. To resolve this, a web-based Internet Java Phone (or IJPhone) which can be downloaded from
the Internet and run from standard Java-compliant web browser, is proposed in this paper. The IJPhone system consists of two
main components: the Web-based Telephone Exchange for user connection and Internet Java Phone Applet for establishing real-time
Internet voice communication. In addition, as Java applets have certain security restrictions placed on them, the paper also
discusses the method proposed to overcome them.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
995.
Gregory Gutin Arash Rafiey Stefan Szeider Anders Yeo 《Theory of Computing Systems》2007,41(3):521-538
A linear arrangement (LA) is an assignment of distinct integers to the vertices of a graph. The cost of an LA is the sum
of lengths of the edges of the graph, where the length of an edge is defined as the absolute value of the difference of the
integers assigned to its ends. For many application one hopes to find an LA with small cost. However, it is a classical
NP-complete problem to decide whether a given graph G admits an LA of cost bounded by a given integer. Since every edge of
G contributes at least one to the cost of any LA, the problem becomes trivially fixed-parameter tractable (FPT) if parameterized
by the upper bound of the cost. Fernau asked whether the problem remains FPT if parameterized by the upper bound of the cost
minus the number of edges of the given graph; thus whether the problem is FPT "parameterized above guaranteed value." We
answer this question positively by deriving an algorithm which decides in time O(m + n + 5.88k) whether a given graph with m edges and n vertices admits an LA of cost at most m + k (the algorithm computes such an LA
if it exists). Our algorithm is based on a procedure which generates a problem kernel of linear size in linear time for a
connected graph G. We also prove that more general parameterized LA problems stated by Serna and Thilikos are not FPT, unless
P = NP. 相似文献
996.
Formaldehyde and malonaldehyde were identified upon exposure of squalene to ultraviolet (UV) irradiation at 300 nm. Formaldehyde
was derivatized by reaction with cysteamine to form thiazolidine; malonaldehyde was derivatized by reaction withN-methylhdyrazine to produceN-methylpyrazole. The derivatives were subsequently analyzed with a gas chromatography equipped with a fused silica capillary
column and a nitrogen/phosphorus detector. The levels of formaldehyde and malonaldehyde produced increased with irradiation
time. The amount of formaldehyde produced reached a maximum of 3.40 nmol/mg squalene after 7 hr irradiation; the maximum amount
of malonaldehyde generated, 0.92 nmol/mg, was found after 5 hr of irradiation. Prior to this study, formaldehyde had not been
reported as a photoproduct of squalene. Acetaldehyde and acetone were also detected in the irradiated squalen,, which may
be formedvia a 6-methyl-5-hepten-2-one intermediate. 6-Methyl-5-hepten-2-one can also undergo breakdown to form malonaldehyde. 相似文献
997.
Large area ordered arrays of macroporous Cadmium Selenide (CdSe) nanostructure, which possesses high refractive index and negligible absorption in the visible spectrum critical for the realization of photonic band gaps, was prepared via colloidal templating by galvanostatic electrodeposition. This work investigates the effect of electrodeposition parameters on the macroporous CdSe nanostructure. Field Emission Scanning Electron Microscope (FESEM) images showed two and three dimensional porous structures, consisting of interconnected close-packed arrays of pores. For CdSe thin film of thickness less than 1/3 of the diameter of a polystyrene sphere, it showed a monolayer of circular pores. As for film thickness close to the diameter of the sphere, the pores adopted irregular rounded triangular shapes. When the film thickness was more than one layer of the colloidal polystyrene template, the pores were spherical and had the same diameter as the polystyrene spheres. X-ray Diffraction (XRD) showed that the CdSe films prepared had a cubic structure with nanometer grain size, which was smaller than the diameter of the template spheres as well as the diameter of the interconnected channels. A range of 45–70 nm thick CdSe films with > 90% optical transmittance showed that there was negligible absorption at wavelength of 750 nm. In addition, the CdSe thin film exhibited a band gap energy of 2.07 eV, blue-shifted from the characteristic 1.7 eV of CdSe. This blue-shift characteristic of the deposited CdSe film further indicated that it was nanocrystalline which is potentially useful in photonic applications. 相似文献
998.
A series of poly(n-butyl acrylate)/polystyrene IPNs and semi-1 IPNs with deliberately controlled graft levels were synthesized via a urethane chemical coupling method. Also prepared were a series of semi-2 IPNs with the molecular weight of polymer II as the variable. The more highly grafted IPNs displayed poorly defined morphologies in which the domain structures were irregular and phase domain boundaries were characterized by fibrillar and interphase regions. A single glass transition peak was another feature of the more highly grafted IPNs. Polymer network II formed in the presence of linear polymer I results in morphologies dependent on the molecular weight of linear polymers. In the semi-2 IPNs, polymer I molecular weights below Mv = 20,000 caused polymer I to behave like a plasticizer or a diluent. The domain sizes of semi-2 IPNs agree with theoretical predictions developed by the present authors. 相似文献
999.
A series of new theoretical equations for predicting the domain size in interpenetrating polymer networks, IPN's, and related materials was derived. The equations are based on a domain formation process comprising the crosslinking density of each polymer, mixing and demixing thermodynamics, network swelling and elastic deformation of each polymer network, and the interfacial tension between two polymers. The new equations are applicable to both crosslinked and linear materials. The experimental variables required to determine the domain size include the volume fraction and crosslink level of each polymer (or molecular weight, if linear), the interfacial tension, and the temperature. The theory was applied to poly(n-butyl acrylate)/polystyrene IPN's and semi-IPN's. The results are also compared with the earlier theory of Donatelliet al. 相似文献
1000.
Lin Jia Jian Guo Ma Kiat Seng Yeo Xiao Peng Yu Manh Anh Do Wei Meng Lim 《Microwave and Wireless Components Letters, IEEE》2006,16(4):194-196
A dual band, fully integrated, low phase-noise and low-power LC voltage-controlled oscillator (VCO) operating at the 2.4-GHz industrial scientific and medical band and 5.15-GHz unlicensed national information infrastructure band has been demonstrated in an 0.18-/spl mu/m CMOS process. At 1.8-V power supply voltage, the power dissipation is only 5.4mW for a 2.4-GHz band and 8mW for a 5.15-GHz band. The proposed VCO features phase-noise of -135dBc/Hz at 3-MHz offset frequency away from the carrier frequency of 2.74GHz and -126dBc/Hz at 3-MHz offset frequency away from 5.49GHz. The oscillator is tuned from 2.2 to 2.85GHz in the low band (2.4-GHz band) and from 4.4 to 5.7GHz in the high band (5.15-GHz band). 相似文献