@article{jeon_rahman_2007, title={A neural network model for prediction of pile setup}, ISSN={["2169-4052"]}, DOI={10.3141/2004-02}, abstractNote={ The time-dependent increase in pile capacity after its driving may be significant. A reliable prediction of this increase (setup) may lead to a significant saving in pile design. A neural network model to predict pile setup was developed. A database derived from field tests reported in the literature showing setup of driven piles was compiled, with six variables selected as input parameters: soil type, pile type, pile diameter, pile length, time after pile installation, and initial effective stress at tip. Ultimate pile capacity at beginning of restrike (QBOR) is the sum of pile capacity (QEOD) at end of drive and increased in capacity (ΔQBOR) caused by setup, which in this study is predicted by a backpropagation neural network. The results demonstrate that the neural network model provides a better prediction than predictions by the available empirical methods. A neural network model can serve as a reliable tool for the prediction of pile setup, and further training with additional data will lead to additional improvement in the quality of prediction. }, number={2004}, journal={TRANSPORTATION RESEARCH RECORD}, author={Jeon, Jongkoo and Rahman, M. Shamimur}, year={2007}, pages={12–19} }
 @article{jeon_sanders_kim_littlejohn_2000, title={Exciton binding energies in GaN/AlxGa1−xN pseudomorphic quantum wells}, volume={27}, ISSN={0749-6036}, url={http://dx.doi.org/10.1006/spmi.1999.0819}, DOI={10.1006/spmi.1999.0819}, abstractNote={Abstract Interband transitions of pseudomorphic GaN/ Al x Ga 1 −  x N quantum wells are analysed theoretically with respect to the piezoelectric field utilizing a 6  ×  6 Rashba–Sheka–Pikus (RSP) Hamiltonian. Band structure modifications due to the built-in Stark effect explain a shift of the emission peak in GaN/ Al 0.15 Ga 0.85 N of up to 400 meV. Quantum well exciton binding energies are calculated by the variational method and are discussed in terms of spatial separation of electrons and holes by the built-in electric field, as well as the interaction between valence subbands.}, number={1}, journal={Superlattices and Microstructures}, publisher={Elsevier BV}, author={Jeon, J.-B and Sanders, G.D and Kim, K.W and Littlejohn, M.A}, year={2000}, month={Jan}, pages={53–58} }
 @article{jeon_sanders_kim_littlejohn_1999, title={Piezoelectric and excitonic effects on optical properties of pseudomorphically strained wurtzite GaN quantum well lasers}, number={162}, journal={Compound semiconductors 1998  (Institute of Physics conference series;  no. 162)}, publisher={Bristol; Philadelphia: Institute of Physics Pub.}, author={Jeon, J. B. and Sanders, G. D. and Kim, K. W. and Littlejohn, M. A.}, year={1999}, pages={37–42} }
 @article{wang_jeon_sirenko_kim_1997, title={Piezoelectric effect on optical properties of pseudomorphically strained wurtzite GaN quantum wells}, volume={9}, ISSN={1041-1135 1941-0174}, url={http://dx.doi.org/10.1109/68.584971}, DOI={10.1109/68.584971}, abstractNote={The presence of internal strain in wurtzite quantum-well (QW) structures may lead to the generation of large polarization fields. These piezoelectric fields cause a spatial separation of the electrons and holes inside the QW to screen the internal fields. A self-consistent calculation of optical gain and the corresponding differential gain is presented in pseudomorphically strained GaN quantum wells as a function of carrier density. Based on the local exchange-correlation potential, electron and hole band structures are obtained by coupling Poisson's equation with an effective-mass Schrodinger equation in the conduction band and an envelope-function (or k/spl middot/p) Hamiltonian in the valence band. Our calculations show that self-consistent calculations including the piezoelectric effects are essential for accurate description of strained wurtzite QW structures.}, number={6}, journal={IEEE Photonics Technology Letters}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Wang, Jin and Jeon, J.B. and Sirenko, Yu.M. and Kim, K.W.}, year={1997}, month={Jun}, pages={728–730} }
 @article{jeon_lee_sirenko_kim_littlejohn_1997, title={Strain effects on optical gain in wurtzite GaN}, volume={82}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.365824}, DOI={10.1063/1.365824}, abstractNote={Strain effects on optical gain in hexagonal bulk GaN are calculated and explained in terms of the change in the effective hexagonal crystal field component. Qualitatively, even unstrained wurtzite structures correspond to cubic crystals with a proper biaxial stress applied. Such biaxial stress results in effective tensile deformation along the c axis ([111] direction in cubic crystals) and compressive strain in the perpendicular plane. Therefore, the light mode with a polarization vector parallel to the c axis is suppressed, while the mode with a perpendicular polarization is enhanced in wurtzite structures. Thus, compared to cubic structures with similar material parameters, a strong optical anisotropy of wurtzites results in enhanced gain for certain light polarizations, which make wurtzite structures superior for lower-threshold lasing. These qualitative arguments are illustrated by numerical calculations of optical gain in biaxially strained wurtzite GaN, based on a 6×6 envelope-function Hamiltonian.}, number={1}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Jeon, J. B. and Lee, B. C. and Sirenko, Yu. M. and Kim, K. W. and Littlejohn, M. A.}, year={1997}, month={Jul}, pages={386–391} }
 @article{sirenko_jeon_lee_kim_littlejohn_stroscio_1997, title={Valence band spectra in pseudomorphically strained wurtzite quantum wells}, volume={22}, ISSN={0749-6036}, url={http://dx.doi.org/10.1006/spmi.1996.0215}, DOI={10.1006/spmi.1996.0215}, abstractNote={Abstract A theory for the effects of size quantization and strain on the hole energy spectra in wurtzite AlGaN/GaN/AlGaN quantum wells is presented. The subband structure and dispersion relations for holes in pseudomorphically strained rectangular wells are obtained using an analytical solution of Schrodinger's equation with 3 × 3 matrix Hamiltonian blocks. The effects of strain are interpreted using an analogy between wurzite structures and prestrained zincblende crystals.}, number={2}, journal={Superlattices and Microstructures}, publisher={Elsevier BV}, author={Sirenko, Yu.M. and Jeon, J.-B. and Lee, B.C. and Kim, K.W. and Littlejohn, M.A. and Stroscio, M.A.}, year={1997}, month={Sep}, pages={195–198} }