Decision on the memory size of embedded information systems in an ubiquitous maintenance environment

Over the last decade, emerging information communication technologies have changed our stereotype of manufacturing and service companies. Now products equipped with embedded systems can be wirelessly networked, which leads to gathering and analyzing product status, and taking appropriate actions for maintenance operations during product lifecycle in an ubiquitous way. In this environment, it is necessary to determine the appropriate memory size of embedded systems for minimizing total maintenance system costs because the memory cost is a main cost factor for implementing the ubiquitous maintenance environment. We call it memory size decision problem in this study. We have formulated this problem with a non-linear model having constraints. The decision variable is the memory size of each embedded system. To solve this problem, we have proposed a meta heuristic search method based on genetic algorithms. To show the usefulness of the proposed heuristic, we have carried out computational experiments.     

A study on driver’s workload of telematics using a driving simulator: A comparison among information modalities

Recently, diffusion of telematics services and an explosive increase of in-vehicle display devices, such as Car Navigation Systems (CNSs), are becoming the new causes of traffic accidents. This is due to ‘inattention’ caused by an increase in the driver’s mental workload while he/she is driving. This situation has lead many countries to consider controlling the use of in-vehicle devices while driving through legislation. This research studies the effect of voice or display information systems on drivers through the Driver Eye Movement Analysis and the measurement of response ability. The experiment is carried out in a driving simulator and the results are presented through the comparative analysis of the driver’s visual field via the gaze tracking device and the average of correct answer rates for arithmetic problems.     

Synthesis of type II CdTe/CdSe heterostructure tetrapod nanocrystals for PV applications

We report a facile one-pot synthetic method for the formation of CdTe/CdSe tetrapod nanocrystals with type II band alignment. The crystal growth kinetics can be controlled by changing the injection temperature, rate and concentration of the chalcogen precursor, allowing the structure of CdTe/CdSe tetrapod nanocrystals to be synthesized without changing the underlying chemistry. Only the multiple injection of Se precursor promotes epitaxial growth of a CdSe nanorod on the end of CdTe tetrapod arms. This synthesis shows that the mechanism of tetrapod nucleated growth may be generally applicable for creating other non-core/shell heterostructures. The heterostructure nanocrystals are composed of a CdTe tetrapod core and four CdSe nanorod tips, showing optical properties typical of type II heterostructures that are well suited for photovoltaic applications.     

Electro-conductive properties of poly(3,4-ethylenedioxythiophene)/poly(ionic liquid) films with respect to its structure and morphology

Poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(1-vinyl-3-ethylimidazolium⁺ (trifluoromethane sulfonyl)imide^?) (PIL) complexes were prepared at various PEDOT/PIL molar ratios and dispersed in propylene carbonate at a concentration of 1 wt%. After casting, the maximum conductivity was measured to be 1.2 × 10^?1 S/cm, which could be explained by the 3D variable range hopping model. The optimum surface roughness of the PEDOT/PIL film was measured, showing S_a and S_q values of 5.92 and 11.0 nm, respectively. The conductivity of the polymerized PEDOT without a template process had low conductivity due to its poor surface roughness and large particle size. Therefore, the conductivity of PEDOT/PILs is determined by the particle size, crystallinity and surface morphology. These results were supported by surface mapping microscopy, X-ray photon spectroscopy, and X-ray diffraction.     

Solution phase synthesis of amyloid-cleaving catalysts, two [1,3,5]triazine based compounds

Solution phase synthetic method for amyloid-cleaving catalysts was developed, which bears triazine core, scaffold with bulky and that have various solubility properties; Co(III) complex of cyclen (1,4,7,10-tetraazacyclododecane) for catalytic group, and two imaging agents for binding group. This synthetic method was identified by H-NMR, C-NMR for intermediates and MS for the last products. The yields by this method surpassed solid phase synthesis and took much lower labor, expense, and time. The products which were synthesized by solution phase synthetic method showed good catalytic activities.     

Sol-Gel-Derived Soda Lime-High Silica Glass

Sols containing well-mixed tetraethyl orthosilicate, sodium methylate (CH₃ONa), and Ca metal dissolved in HCIO₄ were hydrolyzed at low pH. After gelation, controlled drying, and subsequent firing at 600°C, the mixture yielded clear glass chunks. Glasses containing 85% to <100% SiO₂, which otherwise are difficult to make by conventional melting techniques, could be made using this technique.     

Anisotropic plasticity model coupled with strain dependent plastic strain and stress ratios

It is necessary to describe properly anisotropic material behavior for realistic numerical analyses of sheet metal forming processes. The implementation of many yield criteria in finite element analysis is very complicated. Various material tests are also required to determine yield function coefficients. Stress ratios and anisotropy coefficients are not constant during forming processes due to deformation induced anisotropy. This paper introduces a yield function using strain dependent plastic strain ratios and stress ratios. The main advantage is to fully utilize the data of uniaxial tensile tests. The described material behavior shows a significantly improved agreement with experimental data.