• Korean Journal of Psychosomatic Medicine
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• v.20 no.2
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• pp.135-138
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• 2012

The pathophysiology of functional gastrointestinal disorder(FGID) is not completely understood, but the importance of the 'Brain-Gut Axis(BGA)' model in FGID is being increasingly recognized. The BGA model is a bidirectional, hard-wired and homeostatic relationship between the central nervous system(CNS) and the enteric nervous system(ENS) via neural, neurohormonal and neuroimmunological pathways. In addition, the BGA model would provide a rationale for the use of psychotropics on FGID. The authors experienced two cases in which duloxetine, a serotonin-norepinephrine reuptake inhibitor, was effective in relieving FGID symptoms as well as psychiatric symptoms such as depression and hypochondriacal anxiety. Therefore we discuss the vignettes from the perspective of BGA theory. Duloxetine showed efficacy in these two patients by reducing visceral hypersensivity (bottom-up regulation) and by relieving depression and anxiety(top-down regulation).

• Clinical Psychopharmacology and Neuroscience
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• v.16 no.4
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• pp.422-433
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• 2018

Objective: Neuropsychiatric manifestations like depression and cognitive dysfunction commonly occur in inflammatory bowel disease (IBD). In the context of the brain-gut axis model, colitis can lead to alteration of brain function in a bottom-up manner. Here, the changes in the response of the hypothalamic-pituitary-adrenal axis and inflammation-related markers in the brain in colitis were studied. Methods: Dextran sodium sulfate (DSS) was used to generate a mouse model of colitis. Mice were treated with DSS for 3 or 7 days and sacrificed. We analyzed the gene expression of brain-derived neurotrophic factor (BDNF), cyclooxygenase 2 (COX-2), and glial fibrillary acidic protein (GFAP), and the expression of GFAP, in the hippocampus, hypothalamus, and amygdala. Additionally, the levels of C-reactive protein (CRP) and serum cortisol/corticosterone were measured. Results: Alteration of inflammatory-related markers varied depending on the brain region and exposure time. In the hippocampus, COX-2 mRNA, GFAP mRNA, and GFAP expression were upregulated during exposure to DSS. However, in the hypothalamus, COX-2 mRNA was upregulated only 3 days after treatment. In the amygdala, BDNF and COX-2 mRNAs were downregulated. CRP and corticosterone expression increased with DSS treatment at day 7. Conclusion: IBD could lead to neuroinflammation in a bottom-up manner, and this effect varied according to brain region. Stress-related hormones and serum inflammatory markers, such as CRP, were upregulated from the third day of DSS treatment. Therefore, early and active intervention is required to prevent psychological and behavioral changes caused by IBD, and region-specific studies can help understand the precise mechanisms by which IBD affects the brain.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.21-24
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• 2005

In this study, new methods of PC panel connection using 'ㄷ'type steel connection is proposed for highly seismic zone. A study was carry out to investigate the connection behavior subjected to cyclic inelastic loading. Three planar type and two T type PC wall will be tested. The variables will be examined were the shear reinforcement existence of top and bottom walls. The specimens will be tested only reverse cyclic loading in accordance with a prescribed displacement history. To transfer the shear strength shear key set up between top and bottom wall. Failure mode, behavior, ductility and energy dissipation capacity of the specimens constructed by new connections wll be compared with those of monolithic walls and Han's(Han, Jun Hee, Seoul National University) model.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.80-87
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• 2018

Consideration is given to the possibility to use changes in buoyancy as a negative reactivity feedback mechanism during temperature transients in heavy liquid metal fast reactors. It is shown that by the proper use of heavy pellets in the fuel elements, fuel rods could be endowed with a passive self-ejection mechanism and then with a negative feedback. A first estimate of the feasibility of the mechanism is calculated by using a simplified geometry and model. If in addition, a neutron poison pellet is introduced at the bottom of the fuel, then when the fuel element is displaced upward by buoyancy force, the reactivity will be reduced not only by disassembly of the core but also by introducing the neutron poison from the bottom. The use of induced buoyancy opens up the possibility of introducing greater amounts of actinides into the core, as well as providing a palliative solution to the problem of positive coolant temperature reactivity coefficients that could be featured by the heavy liquid metal fast reactors.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.101-107
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• 2010

The aim of this paper is to come up with a methodology of constructing an efficient model for multiple representations which can manage and reconcile real-time data about large-scale roads in Vector Domain. In other words, we suggested framework based on a bottom-up approach, which is allowed to integrate data from the network of the lowest level sequentially and perform automated matching in order to produce variable-scale map. Finally, we applied designed multi-LoD model to in-vehicle application.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.162-163
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• 2016

This paper presents a mathematical model for optimizing earthwork allocation plan that minimizes earthwork cost. The model takes into account operational constraints in the real-world earthwork such as material-type (i.e., quality level of material) and quantities excavated from cut-sections, required quality of material and quantities for each embankment layer, top-down cutting and bottom-up filling constraints, and allocation orders. These constraints are successfully handled by assuming the rock-earth material as the three dimensional (3D) blocks. The study is of value to project scheduler because the model identifies the optimal earth allocation plan (i.e., haul direction (cut and fill pairs), quantities of soil, type of material, and order of allocations) expeditiously and is developed as an automated system for usability. It is also relevant to estimator in that it computes more realistic earthworks costs estimation. The economic impact and validity of the mathematical model was confirmed by performing test cases.

• Journal of Korea Planning Association
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• v.53 no.7
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• pp.67-86
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• 2018

This paper attempted to analyze impacts of transition in electricity generation system on a national economy and environmental level in Korea using a recursive computable general equilibrium(CGE) model. In particular, the paper presented a hybrid model combining the top-down CGE model with the bottom-up model which describes the structure of electricity production in detail. The impacts were analyzed by two policy scenarios base on the basic plan for electricity supply and demand proposed by the Korean government. As a result, the paper specifically showed that there exists a trade-off relationship in the policy-making between economic efficiency and environmental level. The paper also suggested that the transition in electricity generation system should be done more gradually and carefully.

• Electronics and Telecommunications Trends
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• v.14 no.6 s.60
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• pp.183-193
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• 1999

통신사업에 경쟁체제가 성숙되어감에 따라 보다 합리적인 접속료 산정방식에 대한 검토가 이루어지고 있는 바, 최근에는 경제적 효율성을 반영한 접속료 산정방식으로서 장기증분비용 방식의 도입에 대한 논의가 활발히 이루어지고 있다. 본 고에서는 대표적인 장기증분비용 모형인 미국의 Hatfield 모형과 BCPM에 대해 비교 분석하고 우리나라에의 시사점을 살펴본다. 이 모형들은 기본적으로 bottom-up 방식을 토대로 장기증분비용을 산정하며 현실 적용성을 높이기 위해 지속적으로 모형을 개선해 오고 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.735-739
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• 2002

경제적 비용을 토대로 한 접속료 산정방식을 적용한다는 취지하에 주요 통신선진국에서는 장기증분비용 (LRIC ; Long Run Incremental Costs)모형에 대한 연구가 활발히 진행중에 있다. 이러한 LRIC 모형에는 미국의 HAI 모형, BCPM 모형, 일본 우정성 모형 둥의 공학적인 방법에 의한 LRIC 모형과 영국의 Top-Down 모형과 같이 회계적 자료를 바탕으로 한 LRIC 모형으로 구분될 수 있다. 이에 본고는 현재 세계적으로 선호되고 있는 Bottom-up 방식의 LRIC모형을 구축하기 위한 선진외국의 가입자망 재설계 방법을 살펴보았다.

• Fire Science and Engineering
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• v.32 no.6
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• pp.69-73
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• 2018

This study examined the reduction effect of a hydrodynamic force acting on the vertical wall of a portable water storage tank with a convex bottom floor. For the numerical simulation, the linearized Peregrine's equation was used to analyze the lapping waves in the tank caused by water falling from a supplying nozzle. The hydrodynamic force could be calculated by measuring the maximum run-up wave height at the vertical wall. The initial conditions of the numerical experiments were set up by controlling the positions and heights of the water supplying nozzle. Finally, the hydrodynamic force acting on the vertical wall can be reduced by the convex bottom design of the portable water storage tank so it can be applied to improve the structural stability.