• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.596-608
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• 2003

Weaning is a complex phase when the mammal suffers the action of different stressors that contribute to negatively affect the efficiency of the intestinal mucosa and of the whole local integrated system, that acts as barrier against any nocuous agent. The components of this barrier are mechanical, chemical, and bacteriological; immunological and not. The development of contact with a saprophyte microflora and the maintenance of feed intake after the interruption of motherly nutrition are essential for the maturation of an equilibrated local immune function and for a functional integrity of villi. Opportunities and limits of some dietary strategies that can contribute to reduce negative effects of weaning on health and performance are discussed. Knowledges on the possible mechanism of action of probiotics are upgraded, particularly for their supposed role in the balance between different immune functions (effectory/regulatory). Some tools to control pathogen microflora are reviewed (acids, herbs, immunoglobulin sources) and practical feeding systems are proposed.

• Journal of the Korean Statistical Society
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• v.33 no.2
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• pp.245-254
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• 2004

This paper derives a distribution function of the terminal value and running maximum of two-dimensional Brownian motion {X($\tau$) = (X$_1$($\tau$), X$_2$ ($\tau$))', $\tau$ 〉0}. One random variable of the joint distribution is the terminal time value, X$_1$ (T). The other random variable is the maximum of the Brownian motion {X$_2$($\tau$), $\tau$〉} between time s and time t. With this distribution function, this paper also derives an explicit pricing formula for an outside barrier option whose monitoring period starts at an arbitrary date and ends at another arbitrary date before maturity.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.73-78
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• 2003

This presentation derives a distribution function of the terminal value and running maximum of two-dimensional Brownian motion {X(t) = (X$_1$(t), X$_2$(T))', t > 0}. One random variable of the joint distribution is the terminal time value of the Brownian motion {X$_1$(t), t > 0}. The other random variable is the partial-time running maximum of the Brownian motion {X$_2$(t), t > 0}. With this distribution function, this presentation also derives an explicit pricing formula for a barrier option whose monitoring period of the option starts at an arbitrary date and ends at another arbitrary date before maturity.

• Journal of The Korea Institute of Healthcare Architecture
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• v.10 no.2
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• pp.125-133
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• 2004

Safety, accessibility and distinguishment as the concept of architectural planning and design are demanded in staircases due to increase of the old aged people and disabled people's enlarged social participation. In this research is tried to provide the importance of vertical walking function at the design for the staircases. For this reason, structural elements of the staircases are studied in the ergonomic aspect for barrier-free environment and a comparative study is made on the regulations of the staircases in the inside and outside of the country in disabled & aged people's view. Based on this study, the quality of the staircases in public facilities and Apartments is analyzed. As the result, it has been proved that the vertical walking function of the staircases is the most fundamental characteristic of the staircases design before everything else.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.42-47
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• 2014

This paper investigates an adaptive approximation design problem for the tracking control of output-constrained non-affine pure-feedback systems. To satisfy the desired performance without constraint violation, we employ a barrier Lyapunov function which grows to infinity whenever its argument approaches some limits. The main difficulty in dealing with pure-feedback systems considering output constraints is that the system has a non-affine appearance of the constrained variable to be used as a virtual control. To overcome this difficulty, the implicit function theorem and mean value theorem are exploited to assert the existence of the desired virtual and actual controls. The function approximation technique based on adaptive neural networks is used to estimate the desired control inputs. It is shown that all signals in the closed-loop system are uniformly ultimately bounded.

• Journal of Ginseng Research
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• v.44 no.6
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• pp.799-807
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• 2020

Background: The skin acts as a barrier to protect organisms against harmful exogenous agents. Compound K (CK) is an active metabolite of ginsenoside Rb1, Rb2 and Rc, and researchers have focused on its skin protective efficacy. In this study, we hypothesized that increased expression of the serine protease inhibitor Kazal type-5 (SPINK5) may improve skin barrier function. Methods: We screened several ginsenosides to increase SPINK5 gene promoter activity using a transactivation assay and found that CK can increase SPINK5 expression. To investigate the protective effect of CK on the skin barrier, RT-PCR and Western blotting were performed to investigate the expression levels of SPINK5, kallikrein 5 (KLK5), KLK7 and PAR2 in UVB-irradiated HaCaT cells. Measurement of transepidermal water loss (TEWL) and histological changes associated with the skin barrier were performed in a UVB-irradiated mouse model and a 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis-like model. Results: CK treatment increased the expression of SPINK5 and decreased the expression of its downstream genes, such as KLKs and PAR2. In the UVB-irradiated mouse model and the DNCB-induced atopic dermatitis model, CK restored increased TEWL and decreased hydration and epidermal hyperplasia. In addition, CK normalized the reduced SPINK5 expression caused by UVB or DNCB, thereby restoring the expression of the proteins involved in desquamation to a level similar to normal. Conclusions: Our data showed that CK contributes to improving skin-barrier function in UVB-irradiated and DNCB-induced atopic dermatitis-like models through SPINK5. These results suggest that therapeutic attempts with CK might be useful in treating barrier-disrupted diseases.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.238-238
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• 2006

Through ultra-violet photoemission spectroscopy in-situ experiment, 0.67 eV energy barrier between 1-hexadecanethiol (HDT)-modified gold and pentacene was observed, which was 0.03 eV smaller than the energy barrier between bare gold and pentacene despite HDT modified gold had 0.8 eV lower work function than that of bare gold. This result is opposed to the idea that increasing the work function a metal decreases the energy barrier. This can be explained by two factors. One is the absence of interface dipole, which is observed in pentacene deposited on gold. The other is reduced ionization energy which can be explained through polarization energy or electronic splitting of molecular orbital with more crystalline structure observed through X-ray diffraction patterns.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.76-85
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• 2022

One of the most fundamental challenges when designing controllers for dynamic systems is the adjustment of controller parameters. Usually the system model is used to get the initial controller, but eventually the controller parameters must be manually adjusted in the real system to achieve the best performance. To avoid this manual tuning step, data-driven methods such as machine learning were used. Recently, reinforcement learning became one alternative of this problem to be considered as an agent learns policies in large state space with trial-and-error Markov Decision Process (MDP) which is widely used in the field of robotics. However, on initial training step, as an agent tries to explore to the new state space with random action and acts directly on the controller parameters in real systems, MDP can lead the system safety-critical system failures. Therefore, the issue of 'safe exploration' became important. In this paper we meet 'safe exploration' condition with Control Barrier Function (CBF) which converts direct constraints on the state space to the implicit constraint of the control inputs. Given an initial low-performance controller, it automatically optimizes the parameters of the control law while ensuring safety by the CBF so that the agent can learn how to predict and control unknown and often stochastic environments. Simulation results on a quadrotor UAV indicate that the proposed method can safely optimize controller parameters quickly and automatically.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.1-8
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• 2008

Epidermis is one of the most dynamic organs in the human body. Multiple layers of keratinocytes in the epidermis continuously undergo proliferation, differentiation, and desquamation cycles, which is the bases of maintaining the epidermal homeostasis. Epidermal homeostasis eventually leads to establish and maintain permeability barrier homeostasis, the most important function of the epidermis. The permeability barrier is located in the stratum corneum. Tightly coordinated regulations are required for the sustained normal barrier function. Extensive studies have established that several nuclear hormone liposensors, including peroxisome proliferator-activated receptor a PPARa, PPARb/d, PPARg and LXRs are expressed in keratinocyte. Activation of PPARs and LXRs could provide a mechanism to coordinate the formation of the corneocytes and extracellular lipid membranes that constitute the stratum corneum. Topical application of PPAR/LXR ligands to murine skin results in the increased expression of keratinocyte differentiation-related proteins, such as involucrin, loricrin, profilaggrin, and trans-glutaminase 1, which would stimulate cornified envelope formation. In conclusion, topical application of ligands or activators of PPAR/LXR as an epidermotherapy would be a promising option to deal dry skin conditions such as atopy.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.93-102
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• 2021

This paper describes the process of developing a concrete median barrier of SB4 grade with anti-glare function. The development section has a height and width of 1,270mm and 560mm, respectively. A wire mesh is placed in the center of the cross section to improve the protection performance. Collision analysis predicted that this section satisfies the strength and occupant protection performance, and that no damage to the barrier occurs. In the actual collision test, it was confirmed that this section satisfies the strength and occupant protection performance. However, damage was observed on two concrete barrier when the truck crashed. In order to improve the accuracy of the collision analysis of the concrete barrier in the future, it is considered that a study on the model development and continuous collision analysis method for domestic commercial vehicles should be carried out.