Huang Y.-K.,Nan Jeon University of Science and Technology |
Chen P.,National Tsing Hua University |
Kao Y.-J.,National Taiwan University
Physical Review B - Condensed Matter and Materials Physics | Year: 2012
We apply the biorthonormal transfer-matrix renormalization group (BTMRG) to study low-temperature properties of quantum spin chains. Simulations on anisotropic Heisenberg spin-1/2 chains demonstrate that the BTMRG outperforms the conventional transfer-matrix renormalization group by successfully accessing far lower temperature than previously reported, while retaining the same level of accuracy. The power of the method is further illustrated by the calculation of the low-temperature specific heat for a frustrated spin chain. © 2012 American Physical Society.
Wang T.-Y.,National Cheng Kung University |
Chiang H.-M.,Nan Jeon University of Science and Technology
Neurocomputing | Year: 2011
The pervasiveness of information available on the internet means that increasing numbers of documents must be classified. Text categorization is not only undertaken by domain experts, but also by automatic text categorization systems. Therefore, a text categorization system with a multi-label classifier is necessary to process the large number of documents.In this study, a proposed multi-label text categorization system is developed to classify multi-label documents. Data mapping is performed to transform data from a high-dimensional space to a lower-dimensional space with paired SVM output values, thus lowering the complexity of the computation. A pairwise comparison approach is applied to set the membership function in each predicted class to judge all possible classified classes. To better explain the proposed model, a comparative study using Reuter's data sets is performed on several multi-label approaches such as Naive Bayes, Multi-Label Mixture, Jaccard Kernel and Bp-MLL. Though the comparative results of the empirical experiment indicate that the proposed multi-label text categorization system performs better than other methods in terms of overall performance indices, these comparisons are done under the conditions without knowing original settings of parameters. From these comparative studies, it is found that these probabilities of documents appearing in correctly predicted classes and those of documents appearing in the wrongly predicted classes are important properties and we conclude that the probability of 0.5 for model membership function is a good criterion to judge between correctly and incorrectly classified documents from the results of the empirical experiment. © 2011 Elsevier B.V.
Chen K.-H.,Nan Jeon University of Science and Technology |
Su C.-T.,National Yunlin University of Science and Technology
Expert Systems with Applications | Year: 2010
This paper proposes modified particle swarm optimization to solve the problem of activity assignment of fourth party logistics (4PL) with preemptive structure. In practice, decision makers must consider goals of different importance when they encounter 4PL decision problems. Previous studies have adopted weighted fuzzy goal programming to design optimization problems. However, it is difficult for decision makers to determine proper weights. This paper proposes a decision making method based on preemptive fuzzy goal programming and a modified PSO. The proposed method does not require weights, and prevents results without feasible solutions caused by improper resource setting. Furthermore, this paper proposes a modified PSO with mutation operator extension. Numerical analysis shows that proposed modified PSOs prevent algorithms from caving prematurely into local optimums. © 2009 Elsevier Ltd. All rights reserved.
Wang J.-B.,Nan Jeon University of Science and Technology |
Yau H.-T.,National Chung Cheng University
International Journal of Advanced Manufacturing Technology | Year: 2014
It is complex and divergent for the conventional motion controllers to process various G codes using different interpolation algorithms. This impairs programming efficiency and robustness of the controller. In this paper, we propose the universal non-uniform rational B-splines (NURBS)-based interpolator which can simplify the architecture of interpolation in spite of interpreting different kinds of inputs. Direct conversion of long G01 and G02/G03 numerical control (NC) segments to NURBS segment is first implemented. The fitting of multiple short segments into a continuous and smooth NURBS segment is then carried out. More importantly, the universal NURBS-based interpolator utilizes the Cox-de Boor algorithm which is highly efficient and can take advantage of the parallel computing scheme to accelerate the processing speed. Furthermore, due to the construction of real-time environment, the proposed algorithm enables interpretation, look-ahead functions, and motion control to work simultaneously. A 2D NC program possessing hundreds of short G01 segments and long segments (i.e., G02, G03, and long G01) is tested on an in-house developed XY-table with a PC-based motion controller. The results have shown the effectiveness and feasibility of the proposed real-time NURBS-based interpolator. © 2013 Springer-Verlag London.
Wang C.H.,Nan Jeon University of Science and Technology
Advanced Materials Research | Year: 2011
Extending the investigations on (Bi0.5Na0.5)TiO 3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Bi0.5Na 0.5)TiO3-(Bi0.5K0.5)TiO3 [BNT-BKT]. (Bi0.5Na0.5)TiO3 with 7∼30 mol% (Bi0.5K0.5)TiO3 ceramics have been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between rhombohedral (R) and tetragonal (T) was found at the composition 0.82BNT-0.18BKT with correspondingly enhanced piezoelectric properties. The electromechanical planar coupling factor is higher for compositions near the MPB. The mechanical quality factor (Qm), planar coupling coefficient (kp) and thickness coupling coefficient (kt) of 0.82BNT-0.18BKT ceramics were 125, 28.8% and 47.4%, respectively. © (2011) Trans Tech Publications.
Lin Y.-H.,Nan Jeon University of Science and Technology
IEEE Transactions on Power Delivery | Year: 2011
The analysis of partial discharge (PD) contributes significantly to the evaluation of the status of insulation in terms of power equipment. In recent years, wavelet transform and equivalent bandwidth and time have been the most common various developing methods associated with noise suppression. This study introduces the use of membership weight function and k-means clustering to classify measured data, in order to assist engineers in making accurate statistical judgments. PD signals can be detected through the analysis of shape features (pulse equivalent bandwidth, rise time, pulse full width at half maximum, discharge magnitude, and pulse polarity). We applied this method to field and laboratory experiments in order to investigate the effectiveness of pulse identification and classification. We found that the proposed method could properly identify noise and a discharge pulse. © 2011 IEEE.
Wang C.-H.,Nan Jeon University of Science and Technology
Advanced Materials Research | Year: 2011
Extending the investigations on (Bi0.5Na0.5)TiO 3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Bi0.5Na 0.5)TiO3-Ba(Sn, Ti)O3. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn, Ti)O3 diffuses into the lattice of (Bi0.5Na0.5)TiO3 to form a solid solution, in which a rhombohedral phase with a perovskite structure was found. It was found that the samples with a low content of Ba(Sn0.06Ti0.94)O3 exhibit relatively good physical and electric properties. For 0.98(Bi0.5Na 0.5)TiO3-0.02Ba(Sn0.06Ti0.94)O 3 ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.16 and 0.57, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 3.56. For 0.98(Bi0.5Na0.5)TiO3-0.02Ba(Sn 0.06Ti0.94)O3 ceramics, the relative density and the thickness coupling coefficient kt reach 98.1% and 0.58, respectively, at the sintering of 1100°C for 5 h. With suitable Ba(Sn xTi1-x)O3 concentration and sintering condition, a dense microstructure and good electrical properties were obtained.
Yu C.-H.,Nan Jeon University of Science and Technology
Applied Mechanics and Materials | Year: 2014
This paper uses the mathematical software Maple for the auxiliary tool to study the partial differential problem of two types of multivariable functions. We can obtain the infinite series forms of any order partial derivatives of these two types of multivariable functions by using differentiation term by term theorem, and hence greatly reduce the difficulty of calculating their higher order partial derivative values. On the other hand, we propose two examples of multivariable functions to evaluate their any order partial derivatives, and some of their higher order partial derivative values practically. At the same time, we employ Maple to calculate the approximations of these higher order partial derivative values and their infinite series forms for verifying our answers. © (2014) Trans Tech Publications, Switzerland.
Wang C.-H.,Nan Jeon University of Science and Technology
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2010
In this paper, the 0.98(Na0.5K0.5)NbO 30.02Ba(Sn0.02Ti0.98)O3 ceramics with the addition of 0-4.0wt% Mn2O3 have been prepared following the conventional mixed oxide process. The disc samples were sintered in alumina crucible at 1100°C for 3 h in air. For 0.98(Na 0.5K0.5)NbO30.02Ba( Sn0.02Ti 0.98)O3 ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode k t reach 0.31 and 0.39, respectively. In the low Mn2O 3 content region (≤1wt%), the decrease of dielectric constant, dielectric loss tangent and planar coupling factor together with the enhancement of mechanical quality factor correspond well to the feature of a hard doping effect on the electrical properties. For 0.98(Na0.5K 0.5)NbO30.02Ba(Sn0.02Ti0.98)O 3 ceramics by doping 1.0 wt% Mn2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.29 and 0.47, respectively, at the sintering of 1100°C for 3 h. The significant rise of dielectric loss tangent and degradation of mechanical quality factor in the high Mn2O 3 content region (≥2wt%) may be attributed to the appearance of distinct pores in the microstructure. With suitable Mn2O3 doping, a dense microstructure and good electrical properties were obtained. © 2010 The Ceramic Society of Japan.
Huang Y.-K.,Nan Jeon University of Science and Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011
A biorthonormal transfer-matrix renormalization-group (BTMRG) method for non-Hermitian matrices is presented. This BTMRG produces a dual set of biorthonormal bases to construct the renormalized transfer matrix with only half the dimensions of the matrix of a conventional transfer-matrix renormalization group (TMRG). We show that under generic conditions, such biorthonormal bases always exist. Based on a special E•S•E scheme (where S and E represent the system and environment blocks, respectively, and the two dots in between represent two additional physical sites), the BTMRG method can achieve zero truncation of any reduced state in describing both current left and right Perron states so as to reach a high degree of efficiency and accuracy. We believe that the BTMRG constitutes a more powerful and robust tool than conventional TMRG for non-Hermitian matrices and that it would allow us to better understand the collective behaviors and emerging phenomena of strongly correlated many-body systems. We also show that this scheme is particularly adapted to the calculation of the two-site correlation function of a one-dimensional quantum or two-dimensional classical lattice model. © 2011 American Physical Society.