Efficient model of Korean graphemes based on a smartphone keyboard

Smartphones are becoming more advanced, and the use of touch input is increasing. Therefore, various keyboards can be implemented in smartphones. Unlike the button input method, the touch input method can have non-fixed keys that can be freely arranged. Many users are thus interested in the touch input method. In this paper, we propose a Korean grapheme model called ‘Auto Toggle’ by using auto switching between consonants and vowels of Hangul. Also, Auto Toggle is designed and implemented based on the Android platform. Finally, we describe the results of a performance evaluation for the number of buttons pushed for each single syllable of Hangul compared with conventional methods. Additionally, Auto Toggle results in a rapid improvement on typing speed with respect to sentence generation.     

An effective locking scheme of smart multimedia devices with convenience and enhanced security

The touch screen, the fruit of recent IT development, is incorporated into many applications through a variety of touch screen smart multimedia devices (e.g., digital cameras, TVs, door-lock systems, smart phones, tablet PCs and so on). For smart multimedia devices, it provides convenient use of time and space for many people by replacing many desktop PC functions. Although this convenience has gained popularity among the public, the security is usually neglected. In addition, the miniaturization of smart devices provides easy portability, but it also leads to more chances of being lost or stolen. Inherent features are generalized, but the features also increase risk of exposing personal information. As a result, smart multimedia devices provide a variety of locking features to protect personal information. The features include simple hiding of the screen, password buttons, and pattern locks. Although password and pattern lock features exhibit some degree of security, they are vulnerable to shoulder surfing or smudging. In this paper, vulnerable security points of smart multimedia devices are complemented and the locking system for enhanced security (LSES), in which intuitive user interface provides convenience, is proposed. LSES reduces exposure risk factors with various input methods for the lock pattern.     

Roughness of ZnS:Pr,Ce/Ta2O5 interface andits effects on electrical performance of alternating current thin-filmelectroluminescent devices

Roughness effects of neighboring dielectrics on electrical characteristics of thin-film electroluminescent devices were investigated in order to improve the understanding of physics for the devices. Atomic force microscopy analysis reveal that thicker bottom layer of Ta₂O₅ shows rougher surface resulting in the rougher surface of ZnS:Pr,Ce layer. It can be easily seen that the dc leakage current increases rapidly with increase of surface roughness. Furthermore, it is notable that the initiation field of Poole-Frenkel current conduction is lowered by increasing surface roughness of Ta₂O₅ thin film. Internal charge-phosphor field (Q _int-F_p) analysis and capacitance-ac voltage (C-V) analysis for ITO-Ta₂O₅-ZnS:Pr,Ce-Al and ITO-Ta₂O₅-ZnS:Pr,Ce-Ta₂O₅-Al show that the steady state phosphor field is smaller and C-V curve in transition region is less steep with increase of root-mean-square roughness between lower dielectric and phosphor layer in the alternating current thin-film electroluminescent (ACTFEL) devices. Therefore, we conclude that interface roughness is one of the physical factors to change the electrical performance of ACTFEL device     

Conduction mechanisms in barium tantalates films and modificationof interfacial barrier height

The leakage current-voltage characteristics of rf-magnetron sputtered BaTa₂O₆ film in a capacitor with the top aluminum and the bottom indium-tin-oxide electrodes have been investigated as a function of applied field and temperature. In order to study the effect of the surface treatment on the electrical characteristics of as-deposited film we performed an oxygen plasma treatment on BaTa₂O₆ surface. The dc current-voltage, bipolar pulse charge-voltage, dc current-time, and small ac signal capacitance-frequency characteristics were measured to study the electrical and the dielectric properties of BaTa₂O ₆ thin film. All of the BaTa₂O₆ films in this study exhibited a low leakage current, a high breakdown field strength (3-4.5 MV/cm), and a high dielectric constant (20-30). From the temperature dependence of the leakage current, we could conclude that the dominant conduction mechanism under high electrical fields (>1 MV/cm) is ascribed to the Schottky emission while the ohmic conduction is dominant at low electrical fields (<1 MV/cm). Furthermore, the oxygen plasma treatment on the surface of as-deposited BaTa₂O ₆ resulted in a lowering of the interface barrier height and thus, a reduction of the leakage current at Al under a negative bias. This can be explained by the formation of Ba-rich metallic layer by surface etching effect and by filling the oxygen vacancies in the bulk     

Absorption of carbon dioxide into glycidyl methacrylate solution with quaternary onium salts

Carbon dioxide was absorbed into organic solutions of glycidyl methacrylate (GMA) in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa to measure absorption rates of carbon dioxide, from which the reaction kinetics between carbon dioxide and GMA with quaternary onium salts as catalysts was obtained. The reaction rate constants were estimated by the mass transfer mechanism accompanied by the pseudo-first-order reaction method. An empirical correlation formula between the reaction rate constants and the solubility parameters of solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide was presented.