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Search Results: 1 - 10 of 1178 matches for " Tung "
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A free-boundary problem for the evolution $p$-Laplacian equation with a combustion boundary condition
Tung To
Mathematics , 2007,
Abstract: We study the existence, uniqueness and regularity of solutions of the equation $f_t = \Delta_p f = \text{div} (|Df|^{p-2} Df)$ under over-determined boundary conditions $f = 0$ and $|Df| = 1$. We show that if the initial data is concave and Lipschitz with a bounded and convex support, then the problem admits a unique solution which exists until it vanishes identically. Furthermore, the free-boundary of the support of $f$ is smooth for all positive time.
Influence of Microstructural Changes on Some Macro Physical Properties of Cement Mortar during Accelerated Carbonation  [PDF]
Son Tung Pham
Open Journal of Civil Engineering (OJCE) , 2014, DOI: 10.4236/ojce.2014.42008

The objective of this work was to examine the changes in the microstructure and macro physical properties caused by the carbonation of normalised CEM II mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2 concentration. On the microstructure scale, the evolutions of the cumulative pore volume, pore size distribution, and specific surface area during carbonation were calculated from the adsorption desorption isotherms of nitrogen. We also examined the evolution of macro physical properties such as the solid phase volume using helium pycnometry, porosity accessible to water, gas permeability, and thermal conductivity. The conflict between nitrogen porosity and water porosity results indicated that the porous domains explored using these two techniques are different and help to complementarily evaluate the effects of carbonation. This is a multi-scale study where results on microstructural changes can help to explain the evolution of macro physical properties.

Effects of Carbonation on the Microporosity and Macro Properties of Portland Cement Mortar CEM I  [PDF]
Son Tung Pham
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.27005

The aim of this work was to examine the microstructural changes of CEM I standardised cement mortar caused by accelerated carbonation (20% CO2 concentration) using porosity accessible to water and nitrogen adsorption. The conflicted results obtained by these two techniques showed the differences in porous domains explored, while the pore size distributions calculated from nitrogen adsorption provided evolution of the micro and meso pores during carbonation. The porosity accessible to water showed changes in all three porous domains: macro, meso and micro pores. This is because of difference in the molecular sizes between water and nitrogen molecules. Although these two techniques are different, they help to complementarily evaluate the effects of carbonation. The results also indicated the influence of type of cement on microstructural evolutions and the correlation between variations of mesopores volume and specific surface area. Changes in microstructure induce changes in macroscopic properties that we also examined such as the solid phase volume using helium pycnometry, the gas permeability, the thermal conductivity, the thermal diffusivity, and the longitudinal and transverse ultrasonic velocities.

Group Ranking Sequence Decision for Recommendation of Messaging APP  [PDF]
Wei-Feng Tung
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.27002

This research is to develop a novel recommendation service using a unique group ranking sequence technique “Mining Maximum Consensus Sequences from all Users’ Partial Ranking Lists (MCSP)”. MCSP is capable of determining the product’s sequence recommendations based on k-item candidate sequences and maximum consensus sequences. This paper also illustrates the complete decision procedures of group ranking sequences. In terms of popular information products, we select “messaging app” to reveal the MCSP’s group ranking sequence decision. The recommendation service provides that query users search for the product’s recommendation (i.e., messaging app) according to the preference sequences from query users themselves and a great deal of preference sequences from the other users. This paper consists of the definitions, procedures, implementation, and experiment analysis, as well as system demonstrations of MCSP respectively. This research contributes to a kind of systematic service innovation.

ChenHo Tung
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-3362-6
Counting irreducible representations of large degree of the upper triangular groups
Tung Le
Mathematics , 2009,
Abstract: Let $U_n(q)$ be the upper triangular group of degree $n$ over the finite field $\F_q$ with $q$ elements. In this paper, we present constructions of large degree ordinary irreducible representations of $U_n(q)$ where $n\geq 7$, and then determine the number of irreducible representations of largest, second largest and third largest degrees.
Irreducible characters of Sylow p-subgroups of the Steinberg triality groups $^3D_4(p^{3m})$
Tung Le
Mathematics , 2013,
Abstract: In this notes we construct and count all ordinary irreducible characters of Sylow $p$-subgroups of the Steinberg triality groups ${}^3D_4(p^{3m})$.
Supercharacters and pattern subgroups in the upper triangular groups
Tung Le
Mathematics , 2010,
Abstract: Let $U_n(q)$ denote the upper triangular group of degree $n$ over the finite field $\F_q$ with $q$ elements. It is known that irreducible constituents of supercharacters partition the set of all irreducible characters $\Irr(U_n(q)).$ In this paper we present a correspondence between supercharacters and pattern subgroups of the form $U_k(q)\cap {}^wU_k(q)$ where $w$ is a monomial matrix in $GL_k(q)$ for some $k
Processing obstructive sleep apnea syndrome (OSAS) data  [PDF]
Ren Sin Tung, Wai Yie Leong
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.62019

In this study, the EEG signals were processed. Thirteen ICA algorithms were tested to verify the performance efficiency. The EEG signals were recorder using 10/20 international system, based on a 20 minute sleep recording of a severe Obstructive Sleep Apnea Syndrome (OSAS) during NREM and REM sleep. Seven channels were used to record the EEG signals which are sampled at 100 Hz. The performance analysis of the algorithms were investigated to eliminate the loss of the informative EEG signal during the data processing. The denoising results were magnified with the purpose of evaluating the robustness of the denoising algorithms. From the result we obtained, we are able to understand the denoising algorithm is more suitable to process the EEG signal with lower amplitude.

Management of Peptic Ulcer Bleeding Refractory to Endoscopic Treatment  [PDF]
Tung Yen Lee, Cheng Cheng Tung
Open Journal of Gastroenterology (OJGas) , 2016, DOI: 10.4236/ojgas.2016.66021
Abstract: Background: Before the advent of transcatheter arterial embolization (TAE), emergency surgery was the only choice for patients with peptic ulcer bleeding refractory to endoscopic therapy. This study compared the effectiveness of TAE and surgery in patients with peptic ulcer bleeding refractory to endoscopic hemostasis. Materials and Methods: This was a retrospective analysis of 116 patients with peptic ulcer bleeding refractory to endoscopic treatment at our institution. Eighty-three cases were treated with surgery, and 33 cases were managed with TAE. Clinical outcomes were evaluated. Results: There were no differences between groups with respect to the mortality rate (p > 0.05), length of hospital stay, or medical diseases related to mortality. The TAE group exhibited a significantly higher rebleeding rate (p < 0.05). Rebleeding predominantly occurred in patients with type Ia peptic ulcers (Forrest classification) irrespective of the treatment approach. The rebleeding rates in such patents were 30.2% and 56.3% in the surgery and TAE groups, respectively. Patients with rebleeding after further therapy showed high mortality rates (68.6%). The rebleeding rate was not significantly different between the subgroups of patients with type Ia lesions, although there was a higher mortality rate in the TAE group (27.9% vs. 75%, p = 0.001). Conclusions: TAE may be the first-choice therapy for patients with peptic ulcer bleeding refractory to endoscopic treatment, whereas emergency surgery may be used as an alternative in patients with type Ia bleeding at institutions with no 24-hour radiology service or when no experienced radiologist is available.
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