• JSTS:Journal of Semiconductor Technology and Science
• /
• v.7 no.4
• /
• pp.287-298
• /
• 2007

A two-dimensional treatment of the potential distribution under the depletion approximation is presented for poly-crystalline silicon thin film transistors. Green's function approach is adopted to solve the two-dimensional Poisson's equation. The solution for the potential distribution is derived using Neumann's boundary condition at the silicon-silicon di-oxide interface. The developed model gives insight into device behavior due to the effects of traps and grain-boundaries. Also short-channel effects and drain induced barrier lowering effects are incorporated in the model. The potential distribution and electric field variation with various device parameters is shown. An analysis of threshold voltage is also presented. The results obtained show good agreement with simulated results and numerical modeling based on the finite difference method, thus demonstrating the validity of our model.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.15 no.3
• /
• pp.179-184
• /
• 1982

The behavior of continuous flow culture of Lartobacillus bulgricus was investigated by application of Monod's kinetic model. The parameters obtained from Monod's chemostat theory successfully predicted the behavior of the chemostat. Then, it was found that Monod's kinetics were applicable to the growth rate dependence on glucose concentration. Under steady-state condition, the maximum growth rate, saturation constant, and wash out were found to be 0.62/hr, 7.69 g/1, 0.51/hr of continuous culture. And the optimum condition for the highest cell production was 0.41/hr in dilution rate, and at that point the cell production rate was 0.178g/1 hr.

• International Journal of Computer Science & Network Security
• /
• v.23 no.7
• /
• pp.91-100
• /
• 2023

Pervasive computing is characterized by a key characteristic that affects the operating environment of services and users. It places more emphasis on dynamic environments where available resources continuously vary without prior knowledge of their availability, while in static environments the services provided to users are determined in advance. At the same time, Cloud computing paradigm introduced flexibility of use according to the user's profile and needs. In this paper, we aimed to provide Context-Aware Transactional Service applications with solutions so that it can be integrated and invoked like any service in the digital ecosystem. Being able to compose is not enough, each service and application must be able to offer a well-defined behavior. This behavior must be controlled to meet the dynamicity and adaptability necessary for the new user's requirements. The motivation in this paper is to offer design patterns that will provide a maximum of automatism in order to guarantee short reaction times and minimal human intervention. Our proposal includes a cloud service model by developing a PaaS service that allows CATS adaptation. A new specification for the validation of CATS model has been also introduced using the ACTA formalism.

• Membrane and Water Treatment
• /
• v.7 no.3
• /
• pp.193-207
• /
• 2016

Boron is one of the most problematic inorganic pollutants and is difficult to remove in water. Strict standards have been imposed for boron content in water because of their high toxicity at high concentrations. Technologies using membrane processes such as reverse osmosis (RO) and nanofiltration (NF) have increasingly been employed in many industrial sectors. In this work, removal of boron from model water solutions was investigated using polyamide reverse osmosis and nanofiltration membranes. RO-AG, RO-SG, NF-90 and NF-HL membranes were used to reduce the boron from model water at different operational conditions. To understand the boron separation properties a characterization of the four membranes was performed by determining the pure water permeability, surface charge and molecular weight cut-off. Thereafter, the effect of feed pressure, concentration, ionic strength, nature of ions in solution and pH on the rejection of boron were studied. The rejection of boron can reach up to 90% for the three membranes AG, SG and NF-90 at pH = 11. The Spiegler-Kedem model was applied to experimental results to determine the reflection coefficient of the membrane ${\sigma}$ and the solute permeability $P_s$.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.7
• /
• pp.1013-1021
• /
• 2016

This study developed probabilistic models to predict Salmonella growth in processed meat products formulated with varying concentrations of NaCl and $NaNO_2$. A five-strain mixture of Salmonella was inoculated in nutrient broth supplemented with NaCl (0%, 0.25%, 0.5%, 0.75%, 0.5%, 1.0%, 1.25%, and 1.75%) and $NaNO_2$ (0, 15, 30, 45, 60, 75, 90, 105, and 120 ppm). The inoculated samples were then incubated under aerobic and anaerobic conditions at $4^{\circ}C$, $7^{\circ}C$, $10^{\circ}C$, $12^{\circ}C$, and $15^{\circ}C$ for up to 60 days. Growth (assigned the value of 1) or no growth (assigned the value of 0) for each combination was evaluated by turbidity. These growth response data were analyzed with a logistic regression to evaluate the effect of NaCl and $NaNO_2$ on Salmonella growth. The results from the developed model were compared to the observed data obtained from the frankfurters to evaluate the performance of the model. Results from the developed model showed that a single application of $NaNO_2$ at low concentrations did not inhibit Salmonella growth, whereas NaCl significantly (p<0.05) inhibited Salmonella growth at $10^{\circ}C$, $12^{\circ}C$, and $15^{\circ}C$, regardless of the presence of oxygen. At $4^{\circ}C$ and $7^{\circ}C$, Salmonella growth was not observed in either aerobic or anaerobic conditions. When $NaNO_2$ was combined with NaCl, the probability of Salmonella growth decreased. The validation value confirmed that the performance of the developed model was appropriate. This study indicates that the developed probabilistic models should be useful for describing the combinational effect of $NaNO_2$ and NaCl on inhibiting Salmonella growth in processed meat products.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.28 no.4
• /
• pp.165-170
• /
• 2024

This study investigated the impact of soil-structure interaction on multi-degree-of-freedom structures using the shallow-foundation Winkler model, known as the BNWF model. The model's period was determined through eigenvalue analysis and compared to results obtained from FEMA's formula. Results indicated that considering the soil, the structure's period increased by up to 8.7% compared to the fixed-base model, aligning with FEMA's calculations. Furthermore, with adequate ground acceleration, roof displacement increased by 3.4% to 3.8%, while base shear decreased by 4% to 10%. However, roof displacement and base shear increased in some earthquake scenarios due to spectral shape effects in regions with extended structural periods. Foundation damping effects, determined through the foundation's moment-rotation history, grew with higher ground acceleration. This suggests that accounting for period elongation and foundation damping can enhance the seismic design of multi-degree-of-freedom structures.

• Tissue Engineering and Regenerative Medicine
• /
• v.15 no.6
• /
• pp.721-733
• /
• 2018

BACKGROUND: Because three-dimensional (3D) models more closely mimic native tissues, one of the goals of 3D in vitro tissue models is to aid in the development and toxicity screening of new drug therapies. In this study, a 3D skin wound healing model comprising of a collagen type I construct with fibrin-filled defects was developed. METHODS: Optical imaging was used to measure keratinocyte migration in the presence of fibroblasts over 7 days onto the fibrin-filled defects. Additionally, cell viability and growth of fibroblasts and keratinocytes was measured using the $alamarBlue^{(R)}$ assay and changes in the mechanical stiffness of the 3D construct was monitored using compressive indentation testing. RESULTS: Keratinocyte migration rate was significantly increased in the presence of fibroblasts with the cells reaching the center of the defect as early as day 3 in the co-culture constructs compared to day 7 for the control keratinocyte monoculture constructs. Additionally, constructs with the greatest rate of keratinocyte migration had reduced cell growth. When fibroblasts were cultured alone in the wound healing construct, there was a 1.3 to 3.4-fold increase in cell growth and a 1.2 to 1.4-fold increase in cell growth for keratinocyte monocultures. However, co-culture constructs exhibited no significant growth over 7 days. Finally, mechanical testing showed that fibroblasts and keratinocytes had varying effects on matrix stiffness with fibroblasts degrading the constructs while keratinocytes increased the construct's stiffness. CONCLUSION: This 3D in vitro wound healing model is a step towards developing a mimetic construct that recapitulates the complex microenvironment of healing wounds and could aid in the early studies of novel therapeutics that promote migration and proliferation of epithelial cells.

• Computers and Concrete
• /
• v.7 no.2
• /
• pp.169-190
• /
• 2010

The focus of this research effort was characterization of the flexural and tensile properties of a specific ultra-high-strength, fiber-reinforced concrete material. The material exhibited a mean unconfined compressive strength of approximately 140 MPa and was reinforced with short, randomly distributed alkali resistant glass fibers. As a part of the study, coupled experimental, analytical and numerical investigations were performed. Flexural and direct tension tests were first conducted to experimentally characterize material behavior. Following experimentation, a micromechanically-based analytical model was utilized to calculate the material's tensile failure response, which was compared to the experimental results. Lastly, to investigate the relationship between the tensile failure and flexural response, a numerical analysis of the flexural experiments was performed utilizing the experimentally developed tensile failure function. Results of the experimental, analytical and numerical investigations are presented herein.

• The Journal of the Korea Contents Association
• /
• v.7 no.4
• /
• pp.103-113
• /
• 2007

This paper attempts to construct a storytelling model of computer games by using the Greimas's schema of narrative. Analysis target is multi-play of Starcraft, which has the non-linearity and interactivity. As a result, the process of manipulation and sanction, occurred in epistemological level at very short time and the process of competence had lots of small schema of narratives and repeated that small narratives. This model may be applied to other games, because it looks that most of games have very short process of manipulation and sanction at epistemological level and have long process of competence as main game play.

• The Journal of the Acoustical Society of Korea
• /
• v.10 no.1
• /
• pp.52-60
• /
• 1991

This paper describes the study on isolated word recognition by using DHMM(Dynamic Hidden Markov Model) which has dynamic feature of spectrum as a parameter. This paper discusses speech recognition experiment basedon HMM which can evaluate not only instantaneous spectral features but also dynamic spectral features. LPC cepstrum parameters is used as a static feature and LPC cepstrum's regression coefficient is used as a dynamic feature. These two features are quantized by each VQ codebook. DHMM is modeled by receiving static vector and dynamic vector by input. In the whole experiment, as recognition experiment using DHMM shows 92.7% of recognition rate while the experiment using conventional HMM shows 88.8% of recognition rate, DHMM proved to be a useful model.