The Impact of Overfitting and Overgeneralization on the Classification Accuracy in Data Mining

Current classification approaches usually do not try to achieve a balance between fitting and generalization when they infer models from training data. Such approaches ignore the possibility of different penalty costs for the false-positive, false-negative, and unclassifiable types. Thus, their performances may not be optimal or may even be coincidental. This dissertation analyzes the above issues in depth. It also proposes two new approaches called the Homogeneity-Based Algorithm (HBA) and the Convexity-Based Algorithm (CBA) to address these issues. These new approaches aim at optimally balancing the data fitting and generalization behaviors of models when some traditional classification approaches are used. The approaches first define the total misclassification cost (TC) as a weighted function of the three penalty costs and their corresponding error rates. The approaches then partition the training data into regions. In the HBA, the partitioning is done according to some homogeneous properties derivable from the training data. Meanwhile, the CBA employs some convex properties to derive regions. A traditional classification method is then used in conjunction with the HBA and CBA. Finally, the approaches apply a genetic approach to determine the optimal levels of fitting and generalization. The TC serves as the fitness function in this genetic approach. Real-life datasets from a wide spectrum of domains were used to better understand the effectiveness of the HBA and CBA. The computational results have indicated that both the HBA and CBA might potentially fill a critical gap in the implementation of current or future classification approaches. Furthermore, the results have also shown that when the penalty cost of an error type was changed, the corresponding error rate followed stepwise patterns. The finding of stepwise patterns of classification errors can assist researchers in determining applicable penalties for classification errors. Thus, the dissertation also proposes a binary search approach (BSA) to produce those patterns. Real-life datasets were utilized to demonstrate for the BSA

A New Approach of the Online Tuning Gain Scheduling Nonlinear PID Controller Using Neural Network

This chapter presents the design, development and implementation of a novel proposed online-tuning Gain Scheduling Dynamic Neural PID (DNN-PID) Controller using neural network suitable for real-time manipulator control applications. The unique feature of the novel DNN-PID controller is that it has highly simple and dynamic self-organizing structure, fast online-tuning speed, good generalization and flexibility in online-updating. The proposed adaptive algorithm focuses on fast and efficiently optimizing Gain Scheduling and PID weighting parameters of Neural MLPNN model used in DNN-PID controller. This approach is employed to implement the DNN-PID controller with a view of controlling the joint angle position of the highly nonlinear pneumatic artificial muscle (PAM) manipulator in real-time through Real-Time Windows Target run in MATLAB SIMULINK® environment. The performance of this novel proposed controller was found to be outperforming in comparison with conventional PID controller. These results can be applied to control other highly nonlinear SISO and MIMO systems. Keywords: highly nonlinear PAM manipulator, proposed online tuning Gain Scheduling Dynamic Nonlinear PID controller (DNN-PID), real-time joint angle position control, fast online tuning back propagation (BP) algorithm, pneumatic artificial muscle (PAM) actuator

New criteria for exponential stability of linear neutral differential systems with distributed delays

summary:We present new explicit criteria for exponential stability of general linear neutral time-varying differential systems. Particularly, our results give extensions of the well-known stability criteria reported in [3,11] to linear neutral time-varying differential systems with distributed delays

Study of Using Cassava Pulp to Produce Livestock Feed Pellet

In Vietnam, the cassava production capacity is about 10 million tons annually. Indeed, it eliminates approximate 4 million tons of cassava pulp from the cassava starch factories. This amount of cassava is usually dried to feed cattle or fertilizer. However, drying of cassava pulp has its disadvantages such as air pollution, difficult storage and transportation. This study has proposed and successfully tested a line of equipment used to produce pellets from the utilization of fresh cassava pulp bringing from cassava starch processing plants. The processing includes a mixing of fresh cassava pulp with dried cassava starch, pressing and drying of pellets. The experiment results show that when the mixing ratio between cassava starch and cassava residue is 1:10 – 1:5, the cassava pulp pellets after drying achieved the required technical specifications. Hence, it has high volume density, the dried specific weight of the pellets is about 700 kg / m3, the breaking strength of the pellets is greater than 2 kG, the tanning time of the pellets is greater than 116 minutes in water, the moisture content of the pellets is remained in 13% after drying in 5-5.5 hours

The validation of organisational culture assessment instrument in healthcare setting: results from a cross-sectional study in Vietnam

BACKGROUND: Organisational culture (OC) has increasingly become a crucial factor in defining healthcare practice and management. However, there has been little research validating and adapting OCAI (organisational culture assessment instrument) to assess OC in healthcare settings in developing countries, including Vietnam. The purpose of this study is to validate the OCAI in a hospital setting using key psychometric tests and confirmatory factor analysis (CFA). METHODS: This is a cross-sectional study. Self-administered structured questionnaire was completed by 566 health professionals from a Vietnamese national general hospital, the General Hospital of Quang Nam province. The psychometric tests and CFA were utilized to detect internal reliability and construct validity of the instrument. RESULTS: The Cronbach\u27s alpha coefficients (alpha-reliability statistic) ranged from 0.6 to 0.8. In current culture, the coefficient was 0.80 for clan and 0.60 for adhocracy, hierarchy and market dimension, while in expected culture, the coefficient for clan, adhocracy, hierarchy, and market dimension was 0.70, 0.70, 0.70 and 0.60, respectively. The CFA indicated that most factor loading coefficients were of moderate values ranging from 0.30 to 0.60 in both current and expected culture model. These models are of marginal good fit. CONCLUSIONS: The study findings suggest that the OCAI be of fairly good reliability and construct validity in measuring four types of organisational culture in healthcare setting in resource-constrained countries such as Vietnam. This result is a first step towards developing a valid Vietnamese version of the OCAI which can also provide a strong case for future research in the field of measuring and managing organisational culture

Assessment of impacts of utilization on water resources in the basin of trans-boundary Red river system

The Red river system is the large trans-boundary river system, there has been no united system of hydrology stations as well as integrated plan for the water use and management in the whole basin. The trend of water resources change in the Red river system basin has been assessed on the basic of statistic analyses of data observed during the studies, especially in the time when the exploitation of water resources has been intensified for the multisectoral development. This paper shows some of the results from considerations of the water use in the highlands that is influential in water resources in the Red river system basin and the planned reservoirs which are built in the basin of Red river system. The results include the assessment of the state and trend of water resources in the Red river system basin, the trend of water level lowering in the lowlands and its impacts

Optical Properties of Silicon Nanoparticles Prepared by Laser Ablation Method in Various Media

Bright photoluminescent silicon nanoparticles were successfully fabricated from porous silicon target in air and n-hexane using 532 nm line of YAG:Nd pulsed laser. The whole procedure was carried out at room temperature, in atmosphere. The morphology and composition of as-synthesized nanoparticles were characterized by SEM and EDS measurements. Their optical properties were investigated. The PL peak position of the as-synthesized Si nanoparticle ablated in air is slightly blue-shifted in comparison with those ablated in n-hexane, while it was almost no change of peak position of Si nanoparticles fabricated from p-Si in hexane and original p-Si wafer target. In contrast to PL intensity quenching of original p-Si sample and particles produced in air, those produced in n-hexane solvent exhibited an enhancement. The presence of dangling bonds or energy transfer from excited Si particles to oxygen molecules on the surface can be the cause of the quenching effect

Determination of Wavelength Shift of Fiber Bragg Grating Sensors by Tunable Single-mode Diode Laser

We propose a novel principle of determination of fiber Bragg grating (FBG) wavelength shift which is impacted by a variation of physical parameters such as temperature, pressure and/or strain. In common case the wavelength shift of FBG was monitored by wavelength measurement using a high-cost spectrometer and a broad band light source. In our proposed technique the wavelength shift of FBG can be determined by change of lasing wavelength of distributed feedback laser (DFB-laser) due to the change of laser substrate temperature. The maximal opto-electrical intensity of photodetector would be obtained when the laser wavelength and FBG reflection wavelength are coincided. The FBG sensor prototype has shown excellent response for laser temperature change in the range of $10^{\circ}C-50^{\circ}C$ with the ratio $\Delta \lambda /\Delta T$ of the DFB laser is of 77.5 pm.K$^{ - 1}$. Key features of the proposed technique are fabrication of low-cost FBG sensors for civil engineering