THE STABILITY OF CERTAIN SETS OF ATTACHED PRIME IDEALS RELATED TO COSEQUENCE IN DIMENSION > k

Khanh, Pham Huu Korean Mathematical Society 2016 대한수학회보 Vol.53 No.5

Let (R, m) be a Noetherian local ring, I, J two ideals of R, and A an Artinian R-module. Let $k{\geq}0$ be an integer and $r=Width_{>k}(I,A)$ the supremum of lengths of A-cosequences in dimension > k in I defined by Nhan-Hoang [9]. It is first shown that for each $t{\leq}r$ and each sequence $x_1,{\cdots},x_t$ which is an A-cosequence in dimension > k, the set $$\Large(\bigcup^{t}_{i=0}Att_R(0:_A(x_1^{n_1},{\ldots},x_i^{n_i})))_{{\geq}k}$$ is independent of the choice of $n_1,{\ldots},n_t$. Let r be the eventual value of $Width_{>k}(0:_AJ^n)$. Then our second result says that for each $t{\leq}r$ the set $\large(\bigcup\limits_{i=0}^{t}Att_R(Tor_i^R(R/I,\;(0:_AJ^n))))_{{\geq}k}$ is stable for large n.

Effect of Genotype and Dietary Protein Level on Growth Performance and Carcass Characteristics of Fattening Pigs in Central Vietnam

Pham, Khanh Tu,Hoang, Nghia Duyet,Le Duc, Ngoan,Hendriks, W.H.,Van Der Peet-Schwering, C.M.C.,Verstegen, M.W.A. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.8

This study aimed to determine the optimum dietary crude protein level in a typical diet for fattening pigs fed ad libitum under normal climate conditions in Central Vietnam. One hundred and ninety two gilts of Mong Cai local breed (MC), $F_1$ Large White${\times}$Mong Cai and $F_2$ crossbreds of (Landrace${\times}$Mong Cai)${\times}$Large White were used. At the start of the experiment, Mong Cai pigs weighed 12 kg at 11 weeks of age, $F_1$ pigs 12.1 kg at 8 weeks of age and $F_2$ pigs 12.2 kg at 8 weeks of age. Four diets differing in crude protein (CP) content (10.1, 13.1, 16.1 and 18.9% in DM) were formulated from rice bran, corn meal, cassava meal and fish meal. Calculated digestible energy content of the diets ranged from 13.5 to 13.8 MJ per kg DM. Pigs were housed individually in pens of $2.5\;m^2$ each and had ad libitum access to feed in a trough as well as water in bowls. The final weights after a growing period of 150 days were 66, 86 and 96 kg for MC, $F_1$ and $F_2$, respectively. Feed intake of MC pigs was highest at 13.1% CP while $F_1$ and $F_2$ had the highest feed intake at 16.1% CP. The results showed that for MC the maximum gain was obtained at levels between 13 to 16% CP. For the $F_1$ the maximum gain was at dietary protein levels of 16-17%. For $F_2$ the max gain was obtained at CP levels of 16 to 18%. Feed conversion was highest in MC pigs (~4.0) followed by $F_1$ (~3.3) and $F_2$ (~3.1), and within genotypes was lowest at the optimum CP level (p<0.05). Back fat thickness in MC (33.1 mm), $F_1$ (23.0 mm) and $F_2$ (20.5 mm) pigs was different and within genotypes was the lowest at intermediate CP levels. In conclusion, increasing the dietary crude protein contents in practical diets for pigs in Vietnam can increase production on small holder farms. Optimal performance for MC, $F_1$ and $F_2$ pigs is achieved at different dietary crude protein contents.

A study on the reset program to detect insulation faults in the power supply system

Pham Van Khanh(팜반카인),Nguyen Thanh Dat(웬탄닷),Jong-Phil Hong(홍종필) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6

This paper presents a reset program that is used throughout the operation of the Insulation Monitoring Device (IMD) to quickly detect insulation fault when an unexpected insulation fault occurs in the Power Supply Systems (PSS). The reset program can improve the response time up to 4 times.

The stability of certain sets of attached prime ideals related to cosequence in dimension $>k$

Pham Huu Khanh 대한수학회 2016 대한수학회보 Vol.53 No.5

Let $(R,\m)$ be a Noetherian local ring, $I, J$ two ideals of $R$, and $A$ an Artinian $R$-module. Let $k\ge 0$ be an integer and $r=\Width_{>k}(I,A)$ the supremum of lengths of $A$-cosequences in dimension $>k$ in $I$ defined by Nhan-Hoang \cite{NhHo}. It is first shown that for each $t\le r$ and each sequence $x_1, \ldots , x_t$ which is an $A$-cosequence in dimension $>k$, the set $$\big (\overset t{\bigcup\limits_{i=0}} \Att_R(0:_A(x_1^{n_1},\ldots, x_i^{n_i}))\big )_{\ge k}$$ is independent of the choice of $n_1,\ldots, n_t$. Let $r$ be the eventual value of $\Width_{>k}(0:_AJ^n)$. Then our second result says that for each $t\le r$ the set $(\overset t{\bigcup\limits_{i=0}}\Att_R(\Tor_i^R(R/I, (0:_AJ^n))))_{\ge k}$ is stable for large $n$.

Effect of Biot’s Coefficient and Fluid Properties on Isothermal H-M Coupled Consolidation Analysis of Porous Media

Khanh Pham,최현준,이동섭,김기석,최항석 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.6

In this study, a hydraulic-mechanical (H-M) coupling model was implemented, which considers porous media as a deforming porous continuum where fluid flow is taken into account. The primary variables are the time-dependent pore pressure and displacement of the solid skeleton. Physical laws, including the linear momentum balance and mass conservation, are applied to describe the corresponding processes as mechanics and fluid flow occurring within the porous media during the consolidation progress. The general field equations were derived with the aid of a finite element formulation and generalized trapezoidal method to deal with the governing equations in spatial and time domains. In the numerical analysis, the massive diversity of time domain of coupled problems was discussed in detail. In addition, a convergence condition for the partitioned approach applied to deal with a typical matter was proposed. A numerical example was executed to simulate a one-dimensional isothermal consolidation in which a hydraulic-mechanical coupling is mathematically adopted. Finally, a series of parametric studies was carried out to indicate the effect of Biot’s coefficient and fluid properties on the isothermal consolidation of porous media. The results of parametric studies show that the consolidation of porous media can be expedited with compressible particles and less compressible fluids than those with incompressible particles and more compressible fluids, respectively.

Infinite slope stability analysis under transient unsaturated seepage condition

Khanh Pham,Lee Hyobum,Kim Dongku,Choi Hangseok 대한토목학회 2017 대한토목학회 학술대회 Vol.2017 No.10

AN INDEPENDENT RESULT FOR ATTACHED PRIMES OF CERTAIN TOR-MODULES

Khanh, Pham Huu Korean Mathematical Society 2015 대한수학회보 Vol.52 No.2

Let (R, m) be a Noetherian local ring, I an ideal of R, and A an Artinian R-module. Let $k{\geq}0$ be an integer and $r=Width_{>k}(I,A)$ the supremum of length of A-cosequence in dimension > k in I defined by Nhan-Hoang [8]. It is shown that for all $t{\leq}r$ the sets $$(\bigcup_{i=0}^{t}Att_R(Tor_i^R(R/I^n,A)))_{{\geq}k}\;and\\(\bigcup_{i=0}^{t}Att_R(Tor_i^R(R/(a_1^{n_1},{\cdots},a_l^{n_l}),A)))_{{\geq}k}$$ are independent of the choice of $n,n_1,{\cdots},n_l$ for any system of generators ($a_1,{\cdots},a_l$) of I.

Non-cooperative interference alignment for multicell multiuser MIMO uplink channels

Khanh Pham,Kyungchun Lee IET 2017 IET COMMUNICATIONS Vol.11 No.5

<P>Linear interference alignment (IA) is considered a promising interference management technique for future cellular networks. However, its application to practical cellular networks still faces many challenges, two of which are the overhead of sharing global channel state information (CSI) and the cost of signalling dimensionality. These two challenges are resolved in this study via a new linear IA scheme that not only prevents global CSI sharing but also keeps the number of signalling dimensions manageable. While making linear IA more applicable, the proposed scheme provides comparable degrees of freedom to the existing IA schemes in symmetric multicell multiuser multiple-input multiple-output (MIMO) uplink channels.</P>

Analysis of neural network based pedotransfer function for predicting soil water characteristic curve

Pham, Khanh,Kim, Dongku,Yoon, Yuemyung,Choi, Hangseok Elsevier 2019 Geoderma Vol.351 No.-

<P><B>Abstract</B></P> <P>Approximate estimates employing the pedotransfer function (PTF) for predicting the soil-water characteristic curve have received general agreement among the geotechnical engineering society. Notably, the machine-learning-based PTFs (ML-PTFs) offer robust approaches with high prediction accuracy. This study analyzed the potential factors governing the prediction accuracy of the neural-network-based PTF (NN-PTF), which is one of the most popular ML-PTFs. Multiple analysis scenarios for the NN structure, learning algorithm and data processing were presented to evaluate the influence of these components. The analyses were performed on the UNsaturated Soil hydraulic DAtabase, which consists of a broad range of soil types. It is noted that employing the Bayesian regularization significantly improved the prediction accuracy for the same NN structure and optimizing algorithm when compared to using the early stopping, i.e., the maximum reduction in root mean squared error (<I>RMSE</I>) was 0.014. Architectural selection of the network worked most efficiently in case of the Bayesian regularization neural network (BRNN), i.e., <I>RMSE</I> dropped by 36% when the number of neurons increased from 9 to 54. Contrarily, an insignificant variation of <I>RMSE</I> indicated that increasing the NN complexity did not affect the performance of NN-PTF with the conjugate gradient descent and the early stopping. In addition, training the NN-PTF with a well-processed dataset could improve the prediction accuracy, i.e., the maximum reduction in <I>RMSE</I> was 0.004. Overall, the three-hidden-layer BRNN trained by the processed dataset outperformed the other scenarios in consideration, with <I>RMSE</I> = 0.028 and <I>R</I> <SUP> <I>2</I> </SUP> = 0.977. Consequently, the data pre-processing and Bayesian regularization are strongly suggested for deriving the NN-PTF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Explored potential factors governing the NN-PTF performance for predicting SWCC </LI> <LI> Strong correlation between NN-structure and learning algorithm </LI> <LI> Strongly suggested the Bayesian regularization for implementing the NN-PTF </LI> <LI> Significant effect of the database properties on the prediction accuracy of NN-PTF </LI> <LI> Optimal database for deriving the NN is defined by both volume and distribution. </LI> </UL> </P>

Interference Alignment for Multicell Multiuser MIMO Uplink Channels

Pham, Khanh,Lee, Kyungchun IEEE 2016 IEEE Transactions on Vehicular Technology VT Vol.65 No.7

<P>This paper proposes a linear interference alignment (IA) scheme, which can be used for uplink channels in a general multicell multiuser multiple-input-multiple-output (MIMO) cellular network. The proposed scheme aims to align interference caused by signals from a set of transmitters into a subspace that is established by the signals from only a subset of those transmitters, thereby effectively reducing the number of interfering transmitters. The total degrees of freedom (DoF) achievable by the proposed scheme is given in closed-form expression, and a numerical analysis shows that the proposed scheme can achieve the optimal DoF in certain scenarios and provides a higher total DoF than other related schemes in most cases.</P>