• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.458-465
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• 2004

To reaffirm the use of a mainstream CMOS process for designing passive-like attenuator structures, a linearly controlled variable attenuator is realized with 0.35${\mu}{\textrm}{m}$ 2-poly 4-metal CMOS process. It uses the П configuration for large attenuation range and suitable matching property. Compared to conventional passive-like CMOS attenuators, it is demonstrated that this work advances the frequency band from MHz to ㎓ (DC- l㎓), and reduces the size to 700${\mu}{\textrm}{m}$${\times}$300${\mu}{\textrm}{m}$.. Both simulation results and test results are provided. They show the improved linear relation between attenuation and control voltage. It is very useful in CDMA or GSM band, which uses under 1㎓ frequency band. An alternative topology, Bridged-T configuration, is proposed to get over the limit of applications by elevating operation bandwidth. The proposed topology covers over DC-2㎓ frequency band, which means that the proposed architecture can cover the tripleband (800MHz CDMA/GSM, 1.5㎓ GPS, 1.9㎓z PCS system) in applications as well. The simulation results are provided.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.196-201
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• 2006

Electroacupuncture(EA) is commonly used in various diseases. In the present study, the effect of EA in the allergic mouse model was examined. Allergy is generated via immunological mechanism and non-immunological mechanism. Mast cells activated dy those mechanisms get to release various substances such as histamine, leukotrienes, prostaglandin, TNF-$\alpha$, IL-4, IL-6, etc. which induce allergic reactions and the following inflammatory responses. To evaluate the anti-allergic effects of EA, mortality, ear swelling response, vascular permeability and cytokine secretion were investigated in EA group and non-EA group of which mice were compound 48/80-induced allergy model or PCA model. Compound 48/80 induces allergic reaction via non-immunological mechanism and PCA model is generated through the same mechanism with immediate-type(Type1) allergic reaction, one of immunological allergic reactions. EA inhibited compound 48/80-induced ear swelling response but did not inhibit the systemic anaphylaxis. EA also inhibited passive cutaneous anaphylaxis(PCA) activated dy anti-dinitrophenol IgE. In addition, EA inhibited IL-6 and TNF-$\alpha$ secretion from 48 h PCA in mice. These results indicate that EA may be used for the treatment of mast cell-mediated allergic diseases, especially immediate-type(Type 1) allergy and non-immunologically mediated allergy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.518-521
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• 2005

The Structures or buildings nowadays draw more complexity in design due to space limitation and other factor that affect the height and dimensions, that results to instability. So the various methods have been carried out to improve the safety factor from an earthquake or a boom until recently. But, it is very hard to get model precisely because these structures are the non-linear and multi-variable systems. For this reason, we developed the active control system that is applied the adaptive control method on the U type Tuned Liquid Damper(TLD) passive control system. It is proven that the proposed active control strategy of the plate carrying U type TLD system is the more effective control method to suppress the vibration of the structure. The entire hybrid control system is composed of the actuator acted in the opposite direction of the TLD system's motion direction and the active control device with an air pressure adjuster. This paper proposed the adaptive control methods to improve the problem of U type TLD system which is used widely for the passive control of the building. And it is proved by the simulation. In advanced, it is developed the pressure control method that is improved the hybrid controller's performance by using air chamber pressure controller. These methods take the advantage of the decrease of the maximum displacement by using the controller as soon as the impact is loaded. This is a very important element for the safety design and economic design of structures.

• Journal of the Korean institute of surface engineering
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• v.39 no.1
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• pp.25-34
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• 2006

Al-Mg alloy, an open rack vaporizer(ORV) material was reported to be corroded in seawater environments though the ORV material was coupled to thermally sprayed Al-Zn alloy functioning a sacrificial anode. In addition, the corrosion behavior based on the calculated corrosion potential did not match the observed corrosion behavior. Hence, the goal of this study is to get better understanding on Al or Al-Mg alloy coupled to Al-Zn alloy and to provide the calculated corrosion potential representing the corrosion behavior of the ORV material by immersion test, electrochemical tests, and calculation of corrosion and galvanic potential. The corrosion potentials of Al and Al alloys also depended on alloying element as well as surface defects. The corrosion potentials of Al and Al-Mg alloy were changed with time. In the meantime, the corrosion potentials of Al-Zn alloys were not. The corrosion rates of Al-Zn alloys were exponentially increased with zinc contents. The phenomena were explained with the stability of passive film proved by passive current density depending on pH and confirmed by the model proposed by McCafferty. Dissimilar material crevice corrosion (DMCC) test shows that higher content of zinc caused Al-Mg alloy corroded more rapidly, which was due to the fact that higher corrosion rate of Al-Zn makes [$H^+$] and [$Cl^-$] more concentrated within pit solution to corrode Al-Mg alloy. Considering electrochemical reactions within pit as well as bulk in the calculation gives better prediction on the corrosion behavior of Al and Al-Mg alloy as well as the capability of Al-Zn alloy for corrosion protection.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.6
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• pp.452-457
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• 2016

If human body is exposed to the continuous stress, it becomes allostasis load which is the condition of homeostasis broken. Its evolutional ecologic point of view and the relation with chiljeongsnag which is a theory in Oriental Medicine were investigated. Upon evolutional ecologic point of view by Maynard Smith, people can be divided by Hawks and Doves resulting in different types of allostasis in response of the stress. Hawks people who are active and aggressive get easily anger in the stressful situation to be vulnerable to the inflammatory hepatic diseases by enhancing Th1 immune system. On the other hand, Doves people who are passive and calm get easily depressed with sadness in the stressful situation to be vulnerable to the allergic pulmonary diseases by enhancing Th2 immune system. According to constitution theory of Oriental Medicine, Yangin and Eumin show the different features of responses to the stress generating Chiljeongsang. With excessive stress continuously, Yangin consider the feeling of anger mainly resulting in Qi reversal and liver damage, while Eumin consider the feeling of sadness mainly in consumption of Qi and lung damage. Hawks and Yangin, and Doves and Eumin show the common behaviors in response to the stress demonstrating the similar features including allostasis load and Chiljeongsang. In the clinical practices with the stressful patients, the viewpoint to consider the behaviors and feelings of the subjects to receive the stress simultaneously can be the new approaching method in Psychosomatic Medicine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.963-966
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• 2005

Model updating method is known to the area to correct finite element models by the results of the experimental modal analysis. Most common methods in model updating depend on a parametric model of the structure. In this case, the number of parameters is normally smaller than that of modal data obtained from an experiment. In order to overcome this limitation, many researchers are trying to get modal data as many as possible to date. 1 want to name this method multiple modified-system generation method. These Methods consist of direct system modification method and feedback controller method. The direct system modification Is to add a mass or stiffness on the original structure or perturb the boundary conditions. The feedback controller method is to make the closed food system with sensor and actuator so as to get the closed loop modal data. In this paper, we need to focus on the feedback controller method because of its simplicity. Several methods related the feedback controller methods are virtual passive controller (VPC) sensitivity enhancement controller (SEC) and mode decoupling controller (MDC). Among them, we will apply MDC to the model updating problem. MDC has various advantages compared with other controllers, such as VPC and SEC. To begin with, only the target mode can be changed without changing modal property of non-target modes. In addition, it is possible to fix any modes if the number of sensors is equal to that of the system modes. Finally, the required control power to achieve desired change of target mode is always lower than those of other methods such as VPC. However, MDC can make the closed loop system unstable when using incomplete modal data. So we need to take action to avoid undesirable instability from incomplete modal data. In this paper, we address the method to design the unique and robust MDD obtained from incomplete modal data. The associated simulation will be Incorporated to demonstrate the usefulness of this method.

• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.2
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• pp.117-128
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• 2017

This study confirmed the types of shopping information sources during travel abroad, and developed a profile of tourists in terms of demographics, travel, and shopping behavior. Shopping information sources and characteristics of shopping products were identified first. Thereafter, travelers were segmented by their information-seeking behavior. An online survey method was used to get data from Korean vacationers in their 20s-50s, while factor analysis, cluster analysis, ${\chi}^2$ test and ANOVA were applied to analyze data. The results were as follows. First, the shopping information sources of overseas tourists were composed of four factors including sources from travel agents/media, information from travel books and local sources, and word-of-mouth sources. Also, four factors in product types and four product attributes were identified. Second, tourists were clustered into two groups, active and passive shopping information seekers, based on shopping source behavior. Third, two groups differed in terms of demographics, showing an older age and higher income for active shopping source seekers. Active shopping information users tended to join package trips with family members, and they were more satisfied with the trip. With regard to shopping, active shopping source seekers spent more money for shopping and preferred all kinds of shopping goods with an emphasis on travel shopping. In conclusion, shopping information sources seemed to be a meaningful tool for segmenting tourists. Rich, older, family tourists would be an major target market for local retailers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.381-385
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• 2014

This paper investigates the magneto-rheological(MR) mount for the marine diesel-generator(D/G) sets. Sometimes, significant vibrations over the allowable limit are observed on the D/G sets due to their huge excitation forces. Because the severe vibration can lead to structural damages to the D/G sets, it should be reduced below the limit. Although passive mounts with rubber isolators are usually used, the vibration reduction performance is not always sufficient. In addition, expecting that the vibration levels required by customers will get more severe, vibration reduction devices need to be developed. To the aim, the flow mode type of MR mount has been designed. Especially, the annular-radial configuration was adopted to enhance the damping force within the restricted space. The geometry of the mount has been optimized to obtain the required damping force and the magnetic field analysis has been carried out using ANSYS APDL. To verify the performance of the developed MR mount, an excitation test was conducted. In addition, they were applied to a medium-speed diesel generator and it was verified that about 40% of vibration reduction was yielded.

• Steel and Composite Structures
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• v.12 no.5
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• pp.445-464
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• 2012

In order to evaluate the dynamic behavior of passive energy dissipation system, two steps need to be considered for prediction of structural response in the presence of ductile element in an off-centre bracing system. The first is a detailed analysis of the proposed ductile element and the second is the effect of this ductile element on an off-centre bracing system. The use of ductile bracing system is expanding in steel structures in order to increase the force reduction factor. Therefore, regarding the nonlinear behavior of steel material used in an off-centre bracing systems and using ductile element in OBS bracing systems, the seismic evaluation of the mentioned systems seems to be necessary. This paper aims to study linear and nonlinear behavior of steel frames with off-centre bracing system and ductile element, in order to get the best position of these bracing elements. To achieve this purpose, the modeling has been done with ANSYS software. The optimum eccentricity has been obtained by modeling three steel frames with different eccentricities and evaluating the results of them. The analytical results showed that the model OBS-C with 0.3 eccentricities has higher performance among the models.

• Journal of Agricultural Extension & Community Development
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• v.14 no.1
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• pp.59-91
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• 2007

The objectives of this study were 1) to explore the present status of extension services of agricultural experiment station, and 2) to get some implications for ameliorating extension services of agricultural experiment station. The data were collected through the semi-constructed interviews with 11 agricultural researchers in 6 local agricultural experiment stations and 11 farmers who have ever made contact with the researchers. The major findings of this study were as follows: The agricultural experiment stations were providing extension services as expedients to accommodate to new markets and structural changes of organizations, though they are originally research-oriented agencies. The extension methods of agricultural experiment stations were similar with those of extension agencies, and the extension methods used mainly were 'experiment plot demonstration exhibition', 'consultation using telephone, internet, face to face meeting', 'visiting farms and consulting'. These were generally carried out by farmer's request, therefore the extension services of agricultural experiment stations were provided in a passive way so far. Based on the results of this study, the followings are recommended for further development of extension services of agricultural experiment station: The rural development organizations should set principles and support for extension services of agricultural experiment stations. The alternative plans to strengthen the linkage between research and extension have to be made, and these plans should include financial, personnel and systematic arrangements for further development of extension services of agricultural experiment stations.