Knowledge discovery on RFM model using Bernoulli sequence

The objective of this paper is to introduce a comprehensive methodology to discover the knowledge for selecting targets for direct marketing from a database. This study expanded RFM model by including two parameters, time since first purchase and churn probability. Using Bernoulli sequence in probability theory, we derive out the formula that can estimate the probability that one customer will buy at the next time, and the expected value of the total number of times that the customer will buy in the future. This study also proposed the methodology to estimate the unknown parameters in the formula. This methodology leads to more efficient and accurate selection procedures than the existing ones. In the empirical part we examine a case study, blood transfusion service, to show that our methodology has greater predictive accuracy than traditional RFM approaches.     

Economic statistical design of non-uniform sampling scheme X bar control charts under non-normality and Gamma shock using genetic algorithm

This paper presented an approach which simultaneously considered the properties of cost and quality based on the Burr distribution and the non-unifampling scheme. The objective was to determine three parameters, namely, sample size, sampling interval between successive samples, and control limits, when an X bar chart monitors a manufacturing process with Gamma (λ, 2) failure characteristic and non-normal data. The design parameters of the X bar control charts can be obtained through the genetic algorithm (GA) method. An example was also adopted to indicate the solution procedure and sensitivity analyses. The results show that an increase of skewness coefficient (α₃) results in a slight decrease for sample size (n) while an increase of kurtosis coefficient (α₄) leads to a wider control limit width.     

Utilization of self-injection Fabry–Perot laser diode for long-reach WDM-PON

In this investigation we propose and demonstrate a wavelength widely tunable laser source employing a self-injected Fabry–Perot laser diode (FP-LD) for long-reach wavelength-division-multiplexed passive optical network (WDM-PON). By using a tunable bandpass filter and an optical circulator inside the gain cavity, a stable and single-longitudinal-mode (SLM) laser output is achieved. Besides, the proposed laser sources are directly modulated at 2.5 Gb/s for both downlink and uplink transmissions of 85 km single mode fiber (SMF) in PON without dispersion compensation.     

Ultradrawing properties of ultrahigh‐ molecular‐weight polyethylene/carbon nanotube fibers prepared at various formation temperatures

The influence of formation temperature on the ultradrawing properties of ultrahigh‐molecular‐weight polyethylene/carbon nanotube (UHMWPE/CNT) fiber specimens is investigated. Gel solutions of UHMWPE/CNT with various CNT contents were gel‐spun at the optimum concentration and temperature but were cooled at varying formation temperatures in order to improve the ultradrawing and tensile properties of the UHMWPE/CNT composite fibers. The achievable draw ratio (D_ra) values of UHMWPE/CNT as‐prepared fibers reach a maximum when they are prepared with the optimum CNT content and formation temperature. The D_ra value of UHMWPE/CNT as‐prepared fibers produced using the optimum CNT content and formation temperature is about 33% higher than that of UHMWPE as‐prepared fibers produced using the optimum concentration and formation temperature. The percentage crystallinity (W_c) and melting temperature (T_m) of UHMWPE/CNT as‐prepared fiber specimens increase significantly as the formation temperature increases. In contrast, W_c increases but T_m decreases significantly as the CNT content increases. Dynamic mechanical analysis of UHMWPE and UHMWPE/CNT fiber specimens exhibits particularly high α‐transition and low β‐transition, wherein the peak temperatures of α‐transition and β‐transition increase dramatically as the formation temperature increases and/or CNT content decreases. In order to understand these interesting drawing, thermal and dynamic mechanical properties of the UHMWPE and UHMWPE/CNT as‐prepared fiber specimens, birefringence, morphological and tensile studies of as‐prepared and drawn fibers were carried out. Possible mechanisms accounting for these interesting properties are proposed. Copyright © 2010 Society of Chemical Industry     

Environment-adjusted regional energy efficiency in Taiwan

This study applies the four-stage DEA procedure to calculate the energy efficiency of 23 regions in Taiwan from 1998 to 2007. After controlling for the effects of external environments, only Taipei City, Chiayi City, and Kaohsiung City are energy efficient. Note that Kaohsiung City reaches the efficiency frontier due to the adjustment via partial environmental factors such as higher education attainment and transport vehicles. We also find a worsening trend for Taiwan’s energy efficiency. Not only is there a gap of energy efficiency between Taiwan’s metropolitan areas and the other regions, but the gap has also widened in recent years. Those inefficient counties should be given priority and the savings potential. Except for road density, the evidence indicates that each environmental factor has partial incremental effects on input slacks. As more cars and motorcycles are unfavorable externalities affecting partial energy efficiency, the central government should help local governments retire inefficient old motor vehicles, encourage energy-saving vehicle models, and provide convenient mass transportation systems. Besides, people with higher education cause industrial energy inefficient in Taiwan. The conscious of effective energy saving is necessary to schools, communities, and employee accordingly.     

Pd20Pt20Cu20Ni20P20 high-entropy alloy as a bulk metallic glass in the centimeter

A Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ bulk metallic glass (BMG) with a high-entropy (HE) alloy composition and a maximum diameter of 10 mm was fabricated by fluxed water quenching. The system and composition of the Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ alloy were determined from a prototype ternary Pd₄₀Ni₄₀P₂₀ BMG in accordance with two strategic alloy designs of (1) HE alloy defined by an equi-atomic alloy with five or more elements and (2) exchangeability of the constituent elements with a similar chemical nature in the periodic table. Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ HE-BMG had a supercooled liquid range of 65 K and a reduced glass transition temperature of 0.71. Successful formation of Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ HE-BMG is significant to develop new alloys for HE alloys and BMGs.     

Oxygen depletion properties of glucose-grafted polyethylene resins filled with sodium ascorbate/modified iron compounds

Oxygen scavenging plastic can react with oxygen that was trapped in the packaging materials or permeated into the packages, and then, extend the shelf life of food contained in packages. Sodium ascorbate (SA) and modified iron (MFe) compounds were chosen as the main components of oxygen scavengers to prepare the oxygen scavenging LDPE plastics. However, the widely used hydrophobic LDPE packaging material will slow down the oxygen depletion rate of these oxygen scavenger compounds. So glucose was used to modify the hydrophobic property of LDPE to improve the oxygen depletion properties of LDPE oxygen scavenging plastic. The oxygen depletion efficiency of L₉₅[SA_x(MFe)_y]₅ series samples improved initially as the weight ratios of SA/MFe increase, and reached the best as the weight ratios of SA/MFe approach 7/3. After modifying LDPE with glucoses, the oxygen depletion efficiency of each ML₉₅[SA_x(MFe)_y]₅ specimen improved even better than that of the corresponding L₉₅[SA_x(MFe)_y]₅ specimen with the same loading of oxygen scavenger compound, wherein the oxygen depletion efficiency of ML₉₅[SA_x(MFe)_y]₅ series specimens reached the best as the weight ratios of SA/MFe approach 1/9. In consistent with the oxygen depletion properties found in the previous section, the peroxide values of modeled food samples tested in the airtight flask with L₉₅[SA_x(MFe)_y]₅ and ML₉₅[SA_x(MFe)_y]₅ series samples reduce consistently as their oxygen depletion properties improve. In order to understand the interesting oxygen depletion properties of L₉₅[SA_x(MFe)_y]₅ and ML₉₅[SA_x(MFe)_y]₅ series samples, Fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive X-rays analysis of these samples were performed.