Development of a multidisciplinary optimization process for designing optimal pharmaceutical formulations with constrained experimental regions

Pharmaceutical formulation design with the development of analytical technologies and methodologies is an integral part of a drug’s research and development. Conventional pharmaceutical formulation design problems are typically studied under the assumption of an unconstrained experimental region with a single quality characteristic. In real world pharmaceutical formulation design problems, however, we are often faced with multiple quality characteristics with a constrained experimental region due to physical limitations. In order to address these needs, we propose a multidisciplinary optimization process for the optimal design of pharmaceutical formulations by developing a response surface simplex design (RSSD) and a response surface D-optimal design (REDD) for experimental modeling and by developing a partitioned composite desirability function (PCDF) for multidisciplinary optimization. Two actual case studies are also presented here for model verification purposes.     

An approach to multi-criteria assembly sequence planning using genetic algorithms

This paper focuses on multi-criteria assembly sequence planning (ASP) known as a large-scale, time-consuming combinatorial problem. Although the ASP problem has been tackled via a variety of optimization techniques, these techniques are often inefficient when applied to larger-scale problems. Genetic algorithm (GA) is the most widely known type of evolutionary computation method, incorporating biological concepts into analytical studies of systems. In this research, an approach is proposed to optimize multi-criteria ASP based on GA. A precedence matrix is proposed to determine feasible assembly sequences that satisfy precedence constraints. A numerical example is presented to demonstrate the performance of the proposed algorithm. The results of comparison in the provided experiment show that the developed algorithm is an efficient approach to solve the ASP problem and can be suitably applied to any kind of ASP with large numbers of components and multi-objective functions.     

Measurements of Dielectric Properties at Ka-Band Using a Fabry-Perot Hemispherical Open Resonator

A Fabry-Perot hemispherical open resonator is designed and constructed in order to measure dielectric properties of BeO in the Ka-band (26 – 40 GHz) frequency range. Based on both analytic calculations and simulations by a 3-D finite element electromagnetic code, HFSS, the hemispherical open resonator is designed to excite a TEM_0,0,17 mode at 28 GHz. The TEM_0,0,17 mode is experimentally identified by a field perturbation technique. Dielectric measurements are made by both frequency variation and length variation methods. Measurements show that permittivity and loss tangent of BeO are 6.69 and 6.5 × 10^?4 - 7.2× 10^?4, respectively, in the frequency range of 26 – 34 GHz.     

Preparation and electrochromic properties of spin self-assembled polyelectrolyte multilayer films composed of PEDOT:PSS and PAH

Polyelectrolyte multilayer films composed of a polycation (poly(allylamine hydrochloride) PAH) and a polyanion (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) PEDOT:PSS) were prepared by a spin self-assembly method, and their electrochemical and electrochromic properties were investigated. The change in the surface charge and the optical absorption spectra of the multilayer films revealed that sequential deposition of polyelectrolyte was successfully achieved during the spin self-assembly. The electrochromic properties of 20-bilayered PAH/PEDOT:PSS were also investigated. The response time for the coloring and bleaching processes was 6.2 and 2.5 s, respectively, and the coloration efficiency was 199.3 cm²/C. These results indicate that a spin self-assembly process could be a viable alternative for the fabrication of electrochromic devices.     

A class of adaptive hybrid ARQ schemes for wireless links

Wireless links are known to suffer location-dependent, time-varying, and bursty errors. This paper considers a class of adaptive error-control schemes in the data link layer for reliable communication over wireless links in which the error-control code and the frame length are chosen adaptively, based on the estimated channel state/condition. Three error-control schemes are considered according to: (1) the number of Reed Solomon code segments a packet is divided into and (2) the way a lost packet is retransmitted. Through throughput performance and computation complexity analyses, these three schemes are compared, and then one of them is claimed to be the most attractive in terms of computation complexity and practicality even though its throughput performance is not the best. The simulation results also verify that this scheme works well over a time-varying fading channel. Error control for the medium access control (MAC) header and its effect on the performance of each error-control scheme are also considered since, without proper error protection for the header, it would be futile to exercise error control on the user data     

Full software analysis and impedance matching of radio frequencyCMOS integrated circuits

We present a systematic analysis technique of complementary metal-oxide-semiconductor (CMOS) radio-frequency (RF) integrated circuits (ICs). A full simulation program with integrated circuit emphasis (SPICE) simulation of the whole chip including the package and the die, with the parameters extracted from purely software analysis, has been performed. It is shown that the RF impedance matching without S-parameter based techniques is possible and the measured results agree well with our SPICE-only software based technique     

Dependence of thermo-mechanical and mechanical properties of novel fluorophosphate glass on various rare earth dopants

The dependence of thermo-mechanical, and mechanical properties on various rare earth dopants (RE) including Nd₂O₃, Er₂O₃, and Yb₂O₃ in 0.4MgF₂-0.4BaF₂-0.1Ba(PO₃)₂-0.1Al(PO₃)₃ glasses (MBBA system) is systematically investigated. MBBA system doped with RE dopants presented the potential application in the field of communication and high power layer system in the previous reports. In this work, it is found that the density of the doped glass increases with an increasing of RE concentration, which could be understood in terms of cationic field strength (CFS) effect. The Knoop hardness is found to decrease with the loading time and dopant concentration due to the indentation size effect (ISE) effect. The observed decrease of thermal expansion coefficient and the increase of glass transition temperature T _g with increasing dopant concentration are elucidated in terms of the increasing number of strong covalent bonds with increasing RE dopant concentration. Those results will be of paramount importance before designing optical devices.     

Contactless energy transfer using planar printed circuit boardwindings

An energy transfer circuit is proposed which employs a pair of neighbouring printed circuit board windings as a contactless energy transfer device, thereby making it amenable to low-profile designs and suitable for applications in which stringent requirements for height, space and reliability have to be met     

Error concealment using affine transform for H.263 coded videotransmissions

A new error concealment method is proposed that uses motion estimation to consider actual motions, such as rotation, magnification, reduction, and parallel motion, in moving pictures. Since many videos include a variety of complex three-dimensional motions, the proposed method uses an affine transform to estimate the motion of lost data more accurately, thereby producing a higher peak signal-to-noise ratio value and better subjective video quality