• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.1
• /
• pp.26-33
• /
• 2013

Femto-cells are low power/cost, micro-base stations and are main components in heterogeneous networks. However, some of technical issues arise when femto-cells are initially installed. One approach to resolve the problems is to control the transmission (TX) power autonomously via SON(Self-Organized Network) scheme. By controlling the femto-cell TX power, the system throughput performance can be improved or the system overhead is highly reduced. Generally, the TX power for maximizing the system throughput and that for reduced system overhead may not be identical. Therefore, we propose a TX power control scheme by which we can improve the system throughput and reduce the system overhead, simultaneously. When we apply the proposed method, the simulation results show that the system overhead can be reduced by up to 41% compared to the performance of the method which maximizes throughput performance only, and the throughput performance can be improved by up to 63% compared to that of the method which only optimizes the coverage area.

• Herbal Formula Science
• /
• v.19 no.1
• /
• pp.161-174
• /
• 2011

Objectives : The effects of Extraction after Mixture of Bupleuri Radix and Lycii Radicis Cortex on the change of the HPA-Axis system and the Catecholamic system was investigated. Methods : After performing the Forced Swimming Test(FST), the expressions of corticotropin releasing factor(CRF), c-Fos in the paraventricular nucleus(PVN), and tyrosine hydroxylase(TH) in the ventral tegmental area(VTA) and locus coeruleus(LC) were measured by immunohistochemical method. Results : The duration of immobility in FST was significantly decreased in A 100(Extraction after Mixture of Bupleuri Radix and Lycii Radicis Cortex, 100mg/kg) and A 400(Extraction after Mixture of Bupleuri Radix and Lycii Radicis Cortex, 400mg/kg)(p<0.001). The expression of CRF in the PVN was shown the tendency to reduce in A100 and A400. The expression of c-Fos in the PVN was shown the tendency to reduce in A100 and A400. The expression of TH in the VTA was shown the tendency to reduce mildly in A100 and A400. The expression of TH in the LC was significantly reduced in A400(p<0.001). And the dose dependent reduction tendency was shown, respectively. Conclusions : According to the results above mentioned, the immobility, c-Fos and CRF expression was reduced at lower dose and was increased at higher dose. Therefore there is contradictory effects on the HPA Axis system in accordance with the dose. But in the effects on the catecholaminergic system, it significantly reduced the expression of TH in the LC. It was validated that the effect on the catecholaminergic system was ruled by Bupleuri Radix rather than Lycii Radicis Cortex via mainly the noradernergic system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.7
• /
• pp.688-698
• /
• 2012

This paper deals with ROLSO (Reduced Order Luenberger State Observer) design to prevent jackknifing phenomenon of articulated vehicles consisting of the tractor and semi-trailer by using GPS. In addition, by applying the regulator system using ROLSO feedback system, simulation's result presents that articulated vehicle's states are stabilized than the human's PR time (Preception Response time) rapidly. This simulation verifies that the automatic control of articulated vehicle's can be applied for the accident prevention for the time that the driver is unable to manage with the sudden accident. For this simulation, by using the equation of planar motion, the modeling of the articulated vehicle was performed. This modeling was expressed in the state space model. And FOLSO (Full Order Luenberger State Observer), ROLSO were designed by using the state space model of an articulated vehicle's dynamics.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2439-2449
• /
• 2011

Existing grade crossings between railway and roadway area gradually changed to grade separation systems by the law. In the case of new roadway construction which crosses railways, it shall be grade separation system in principle. With the railway underground crossing method, many practices have been developed which can minimize rail displacements and avoid rail release. With these methods, the effects to the train can be reduced. The underground crossing methods can be identified as open-cut methods and non open-cut methods. The open-cut methods include temporary support methods and special rail construction methods. Also the non open-cut methods includes pipe roof methods, front jacking methods, messer shield methods, NTR methods and JES methods. Among these, the most suitable method is applied considering safety, economy, class of each rail system (train passing frequency and velocity), etc. In the non open-cut methods, the cost and duration shall be increased to keep existing rail system during construction. In the open-cut methods which use plate girders, the rail speed shall be restricted due to the displacement and vibration of the girder. In this study new grade separation methods were developed. With this method, the safety during construction can be increased. This method refines temporary support methods, but pc slab girder with huge stiffness is applied instead of plate girders. With this method, the rail displacement can be reduced and higher safety can be obtained during construction. Also construction cost and duration can be minimized because the temporary work and the overburden soil depth can be reduced.

• Structural Monitoring and Maintenance
• /
• v.5 no.3
• /
• pp.417-428
• /
• 2018

In this paper, various model reduction methods were assessed using a shear frame, plane and space truss structures. Each of the structures is one-dimensional, two-dimensional and three-dimensional, respectively. Three scenarios of poor, better, and the best were considered for each of the structures in which 25%, 40%, and 60% of the total degrees of freedom (DOFs) were measured in each of them, respectively. Natural frequencies of the full and reduced order structures were compared in each of the numerical examples to assess the performance of model reduction methods. Generally, it was found that system equivalent reduction expansion process (SEREP) provides full accuracy in the model reduction in all of the numerical examples and scenarios. Iterated improved reduced system (IIRS) was the second-best, providing acceptable results and lower error in higher modes in comparison to the improved reduced system (IRS) method. Although the Guyan's method has very low levels of accuracy. Structures were classified with the excitation frequency. High-frequency structures compared to low-frequency structures have been poor performance in the model reduction methods (Guyan, IRS, and IIRS).

• International Journal of Aeronautical and Space Sciences
• /
• v.13 no.2
• /
• pp.127-153
• /
• 2012

This paper presents an advanced computational method for the prediction of the responses in the frequency domain of general linear dissipative structural-acoustic and fluid-structure systems, in the low-and medium-frequency domains and this includes uncertainty quantification. The system under consideration is constituted of a deformable dissipative structure that is coupled with an internal dissipative acoustic fluid. This includes wall acoustic impedances and it is surrounded by an infinite acoustic fluid. The system is submitted to given internal and external acoustic sources and to the prescribed mechanical forces. An efficient reduced-order computational model is constructed by using a finite element discretization for the structure and an internal acoustic fluid. The external acoustic fluid is treated by using an appropriate boundary element method in the frequency domain. All the required modeling aspects for the analysis of the medium-frequency domain have been introduced namely, a viscoelastic behavior for the structure, an appropriate dissipative model for the internal acoustic fluid that includes wall acoustic impedance and a model of uncertainty in particular for the modeling errors. This advanced computational formulation, corresponding to new extensions and complements with respect to the state-of-the-art are well adapted for the development of a new generation of software, in particular for parallel computers.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.2
• /
• pp.57-62
• /
• 2000

The effect of exhaust gas recirculation(EGR) on the characteristics of exhaust gas emissions, and SFC are experimentally investigated by four-cylinder, four-cycle and direct injection marine diesel engine. In order to reduce the soot contents in the recirculated exhaust gas to intake system of the engines, a soot removal system of a cylinderical-type scrubber is specially designed and manufactured for the experimental system. (1) SFC is increased in downward convex curve style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (2) NOx emission is reduced in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (3) Soot emission is decreased in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (4) CO emission is increased in nearly straight line style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (5) HC emission is not constant tendency with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.6
• /
• pp.392-397
• /
• 2010

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about 10.5~11.3%, and cooling loads are decreased about 29.1~38.3% on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades and the cooling peak load was reduced about 25.7~31.5%. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

• Journal of Haehwa Medicine
• /
• v.18 no.1
• /
• pp.1-8
• /
• 2009

This study analyzed the contents of the research papers of Complementary Medicine concerning the inhalation drug for asthma published in Pubmed during lately 10 years. As a result, the following conclusion was drawn. 1. There were 5 papers concerning 2 review articles, 2 experimental studies and 1 clinical study. 2. Interventions of research papers are glutathione, microorganism fermentation extract (EM-X), ginkgolide and compound Chinese herbal monomer recipe (ligustrazin, baicalin, ginkgolide). 3. There is no controlled study for effect of inhaled glutathione, on the contrary it induced bronchial constriction in sulfites sensitive asthmatics. 4. Inhalation of EM-X reduced airway hyper-reactivity and level of IL-4, IL-5 and IL-13 in OVA challenged asthmatic mice. 5. Ginkgolide nebulized inhalation reduced symptomatic scorings and eosinophil cationic protein, improved FEV1 and PEF. 6. Compound Chinese herbal monomer (CHM) recipe reduced blood eosinophil count, eosinophil count and total cell cound in BALF, depressed airway hyper-responsiveness and airway inflammation.

• Korean Journal of Mathematics
• /
• v.9 no.1
• /
• pp.9-20
• /
• 2001

We are concerned with an activator-inhibitor system proposed by Ohta [8]. The purpose of this paper is to study the dynamics of interfaces in an interfacial problem which is reduced from the system in order to examine how this problem is different from an activator-inhibitor system [3, 7].