Behavior scoring model for coalition loyalty programs by using summary variables of transaction data

OKCashbag (OCB), the largest coalition loyalty program in Korea, offers a number of benefits such as sharing customer data with participating firms and cross-selling. There is great value in utilizing information pertaining to coalition loyal patrons. However, the size of transaction data is huge. We propose how to create necessary summary information by reducing the dimension of coalition transaction data. This information is then utilized to develop a behavior-scoring model. We expect that our study results can contribute to big data analysis for coalition loyalty program.     

Extremely Low Thermal Conductivity in Oxides with Cage-Like Crystal Structure

Although successful examples of thermoelectric materials with the “rattler-in-a-cage” structure include filled skutterudites and clathrate compounds, there has been no report on “rattling” oxides. Here we report the thermal properties of defect pyrochlore (β-pyrochlore) oxides with smaller cations in an oversized cage-like crystal structure. It is clearly shown that the thermal diffusivity, α, and the thermal conductivity, κ, are lower for the oxides containing lighter A-site cations, contradicting the conventional prediction of the phonon thermal conductivity, in which lighter comprising atoms must give higher α and hence κ. These results strongly suggest that the smaller A-site cations with larger size mismatch to the surrounding cage structure enhance the phonon scattering and thereby reduce α and κ. These findings directly evidence the “rattling” effect of the loosely bound cations on the thermal transport properties of oxide materials.     

Monitoring of 14 sulfonamide antibiotic residues in marine products using HPLC-PDA and LC-MS/MS

The main aim of this study is to analyze both domestic and imported marine products in Korea for 14 sulfonamide antimicrobials. Monitoring samples included flatfish, jacopever, sea bream, common eel, blue crab, shrimp, and abalone. In analyzing step, the residues of 14 sulfonamides (SAs) were determined by high-performance liquid chromatography (HPLC) with photodiode array detector. And in confirmatory step, ultra-performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS) was used for unequivocal identification of target compounds.No sulfonamide antimicrobials were found in more than 99% of the samples analyzed in this study. The monitoring results revealed that sulfadiazine was detected in two samples (flatfish and jacopever) below the maximum residue limit (MRL), 100 ?/㎏ as the sum of 14 sulfonamides. Of samples, one common eel containing sulfamethoxazole above the legal residue limit was found, and the detected concentration was 5104 ?/㎏.     

Hole injection polymer effect on degradation of organic light-emitting diodes

Polythienothiophene:poly(perfluoroethylene-perfluoroethersulfonic acid) (PTT:PFFSA) has been used to enhance hole injection into small molecule OLEDs. Compared to devices with polyethylene dioxythiophene polystyrene sulfonate (PEDOT:PSS) as the hole injection layer (HIL), the OLED using PTT:PFFSA as a HIL gives enhanced efficiency and a slower luminance decay as well as a slower rise in operating voltage. Further studies of capacitance–voltage characteristics reveal that positive trapped charges accumulate in the hole transporting layer during operation. These results thus highlight the significance of hole injection layer to OLED operational stability.     

The effect of receptor–polymer matrix compatibility on electrochemical properties of PEO-based polymer electrolytes containing supramolecular additives: Part 2. Ionic transport study

Poly(ethylene oxide)–lithium salt composite electrolytes containing two different derivatives of calix[4]arene were tested as anion complexing agents for I⁻ and CF₃SO₃⁻. Both calix[4]arene derivatives studied have identical anion coordination groups but they have different compatibility with the polymer matrix obtained by chemical linking of the oligo(ethylene oxide) chains to one of the studied calixarenes. The impedance spectroscopy studies showed that the addition of the anion receptor significantly changes the conductivity. The character of this changes strongly depends on the receptor used while the electrochemical stability of these two calixarene receptors measured by cyclic voltammetry is similar. It was also proved that addition of the anion receptor strongly changes the polymer matrix morphology and thermal behavior. By the comparison with the liquid systems which electrical properties were similar to the polymer matrix, we can assume that these changes are a result of anion–receptor interactions.     

Whole cell biotransformation of major ginsenosides using Leuconostocs and Lactobacilli

Various strains of Lactobacillus and Leuconostoc species were evaluated to select the most promising strain to carry out transforming major ginsenosides into minor ginsenosides. Among the experimental lactic acid bacteria (LAB), Leuconostoc mesenteroides KFRI 690, Leuconostoc paramesenteroides KFRI 159, and Lactobacillus delbrueckii KCCM 35486 produced compound K from major ginsenosides precursors (Rb1, Rc, Rd, and F2). KFRI 690 showed the best transforming activity among them. Furthermore, these LABs could biotransform ginsenosides without disrupting the cell to release enzyme activity. The conversion ratio of Rb1 to compound K using KFRI 690 has been enhanced up to 97.8% by adding 2% sucrose into the culture medium. This is the first report on the production of compound K using whole cells of Leu. mesenteroides, Leu. paramesenteroides, and Lb. delbrueckii, which are food grade lactic acid bacteria.