• Land and Housing Review
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• v.15 no.2
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• pp.1-7
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• 2024

The Ministry of Land, Infrastructure, and Transport has been promoting strengthening energy efficiency of old buildings through public green building remodeling projects since 2020. Green remodeling includes both essential and optional construction of passive and active elements. However, there is a lack of integrated designs of passive and active systems and no standards for prioritizing these systems according to the building's age. Therefore, this study examined six public libraries in central region 2 that were expected to be high energy consuming. Remodeling strategy priorities were selected based on potential energy reduction. The libraries were divided into three groups based on their year of construction, completed in the 1980s (Model 1), 1990s (Model 2), and 2000s (Model 3). ECO2-OD, based on ISO 13790 and DINV 18599, was used as the primary energy consumption analysis tool. Simulation results indicated Model 1 and Model 2 benefited most from higher insulation and replacement of mechanical equipment. Model 3 benefited most from upgrading to more energy efficient windows.

• Smart Structures and Systems
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• v.3 no.4
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• pp.405-422
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• 2007

A new hybrid damping technique for vibration reduction in flexible structures, wherein a combination of layers of hard passive damping alloys and active (smart) magnetostrictive material is used to reduce vibrations, is proposed. While most conventional vibration control treatments are based exclusively on either passive or active based systems, this technique aims to combine the advantages of these systems and simultaneously, to overcome the inherent disadvantages in the individual systems. Two types of combined damping systems are idealized and studied here, viz., the Noninteractive system and the Interactive system. Frequency domain studies are carried out to investigate their performance. Finite element simulations using previously developed smart beam elements are carried out on typical metallic and laminated composite cantilever beams treated with hybrid damping. The influence of various parameters like excitation levels, frequency (mode) and control gain on the damping performance is investigated. It is shown that the proposed system could be used effectively to dampen the structural vibration over a wide frequency range. The interaction between the active and passive damping layers is brought out by a comparative study of the combined systems. Illustrative comparisons with 'only passive' and 'only active' damping schemes are also made. The influence and the mode dependence of control gain in a hybrid system is clearly illustrated. This study also demonstrates the significance and the exploitation of strain dependency of passive damping on the overall damping of the hybrid system. Further, the influence of the depthwise location of damping layers in laminated structures is also investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.380-387
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• 2015

Various forms of passive shock absorber have developed to supplement performance which is poorer than that of active shock absorber. It is called 'Hybrid Conventional Damper (HCD)'. Frequency sensing shock absorber that this study will cover belongs to the HCD. This study aims to demonstrate that performance of frequency sensing shock absorber is superior than that of passive shock absorber. Study process is as follows. Firstly, analysis models for both passive shock absorber and frequency sensing shock absorber are developed to secure reliability. Then, elements which cause difference of ride quality are found out through comparison of hysteresis characteristics. By comparison of frequency characteristic, furthermore, damping principle of frequency sensing shock absorber is understood. Also, it determines if the absorber performs well even though maximum excitation speed is changed. Finally, the study proves that performance of frequency sensing shock absorber is superior than that of passive shock absorber after comparing change of damping power in excitation condition that various frequencies are mixed.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.1
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• pp.69-76
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• 2018

This study is to research technical measures for improving energy efficiency in the conservation and reuse of historic buildings focused on the recent research trends and case studies of the west. These measures are broadly classified into three types, the passive measures for saving energy and increasing comfort, the most cost-effective energy saving strategies, and the renewable energy sources. Firstly, the passive measures are divided into the elements and systems. The passive elements are awnings and overhanging eaves, porches, shutters, storm windows and doors, and shade trees. There are also the natural ventilation systems such as the historic transoms, roofs and attics to improve airflow and cross ventilation to either distribute, or exhaust heat. Secondly, the most cost-effective energy efficiency strategies are the interior insulation, airtightness and moisture protection, and the thermal quality improvement of windows. The energy efficiency solutions of modern buildings are the capillary-active interior insulation, the airtightness and moisture protection of interior walls and openings, and the integration of the original historic window into the triple glazing. Beyond the three actions, the additional strategies are the heat recovery ventilation, and the illumination system. Thirdly, there are photovoltaic(PV) and solar thermal energy, wind energy, hydropower, biomass, and geothermal energy in the renewable energy sources. These energy systems work effectively but it is vital to consider its visual effect on the external appearance of the building.

• Korean Institute of Interior Design Journal
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• v.21 no.4
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• pp.114-120
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• 2012

There are lots of buildings which were built before the Legislation on building energy rating system. Remodeling of the buildings would be required for an improvement of the building energy rating system was enforced by the government. In the Passive Building Design, Elements which will be used for the remodeling are Insulation, Window, External venetian blind, Heat exchanger. The Purpose of this study is to indicate a Method for the improvement of Energy saving by an analysis of Construction Cost, Cost Evaluation, Energy performance Efficiency in applied design elements. In this study, the remodeling of existing public buildings to improve energy efficiency rating was applied to extract the elements of design-specific energy performance, efficiency, and the application of the designs that has been analyzed. The results were as follows: applying the design-specific cost-effective investment that represents the economy (investment efficiency/%) surveyed the average insulation(7.0%), triple glazed windows(10.1%), double glazed windows(12.1%), external shading(24.5%), and Heat(77.2%) were analyzed in order to be more efficient. Analysis of the basis of information on the existing public buildings to improve energy efficiency rating for the remodeling depending on driving conditions at a degree of individual difference. The main effect, however, depending on economic investment, design elements, heat exchangers, external awning, double glazed windows, triple glazed windows, insulation, is recommended as review of the order shall be determined.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.401-408
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• 2006

An optimum design method for hybrid control systems is proposed in this study. By considering both active and passive control systems as a combined or a hybrid system, the optimization of the hybrid system can be achieved simultaneously. In the proposed approach, we consider design parameters of active control devices and the elements of the feedback gain matrix as design variables for the active control system. Required quantity of the added dampers are also treated as design variables for the passive control system. In the proposed method, the cost of both active and passive control devices, the required control efforts and dynamic responses of a target structure are selected as objective functions to be minimized. To effectively address the multi-objective optimization problem, we adopt a preference-based optimization model and apply a genetic algorithm as a numerical searching technique. As an example to verify the validity of the proposed optimization technique, a wind-excited 20-storey building with hybrid control systems is used and the results are presented.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.103-104
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• 2014

This paper presents design method of 250[W] grid connected PV-AC module with decoupling and energy storage functions to select optimized passive elements for stable operation. The validity of design of optimized elements is verified by simulation results.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.81-88
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• 2021

In this paper, by applying LTCC substrate, the library of the passive elements is implemented. And it can be used in 24 GHz circuits. Depending on how to use it to the circuit, it is required large value by designing the basic structures such as electrode capacitor and spiral inductor. However they are not available in high-frequency domain, because their SRF(Self-Resonant Frequency) is lower than the frequency of 24-GHz. By solving the limit, this paper devised passive elements classified for the DC and the high-frequency domain. The basic structure is suitable for low frequency under 1~2 GHz like DC. The microstrip λ/8 length stub structure is proposed to use for high-frequency like 24-GHz. The open and short stub structure operate as a capacitor and inductor respectively, also they have their impedances. Through their impedances, we can extract the value with the impedance-related equation. In this paper, the proposed passive elements are produced with the permittivity 7.5 LTCC substrate, the basic structure which are available in the DC constituted a library of capacitance of 2.35 to 30.44 pF and inductance of 0.75 to 5.45 nH, measured respectively. The stub structure available in the high-frequency domain were built libraries of capacitance of 0.44 to 2.89 pF and inductance of 0.71 to 1.56 nH, calculated respectively. The measurements have proven how to diversify value, so libraries can be built more variously. It will be an alternative to the passive elements that it is possible to integrate with the operation circuit of radar module for the frequency 24-GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1287-1293
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• 2008

Antenna switch module(ASM) for quad-band was developed. This module was integrated by RFIPD(RF integrated passive device) and transistor switch instead of LTCC-type device using low pass filters, diodes and passive elements in RF front end module for cellular phone. This module leads to low cost and miniaturization(The area is $5{\times}5\;mm$ and the thickness is 0.8 mm). The insertion loss and the return loss of each band were averagely measured as 1.0 dB(insertion loss), 15.1 dB(GSM/EGSM return loss) and 19 dB(DCS/PCS return loss), respectively.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.286-291
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• 2019

Purpose: This study examined the effects of self-volar gliding combined with a strap and wrist distraction on pain and the active and passive wrist extension range of motion (ROM) in subjects with dorsal wrist pain during partial weight bearing of the hand. Methods: Thirty subjects (14 males and 16 females) with dorsal wrist pain during partial weight bearing through the hand participated in this study. The two different self-volar gliding techniques were performed for each group. Self-volar gliding using a strap (SVGS) and SVGS and wrist distraction (SVGSD) were performed five times for one week for each group. The active and passive ROM of wrist extension and the peak pressure pushed by the hand at pain (PPHP) were measured. An independent t-test was used to compare the improvements of these elements between the two different self-volar gliding techniques. The level of statistical significance was at ${\alpha}=0.05$. Results: The active and passive ROM of wrist extension and PPHP were greater in both self-volar gliding groups after the one week intervention. On the other hand, these parameters were greater in the SVGSD group than in the SVGS group (p<0.05) Conclusion: SVGSD is recommended to improve the active and passive ROM of wrist extension and PPHP in subjects with dorsal wrist pain during partial weight bearing of the hand.