• Geomechanics and Engineering
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• v.27 no.5
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• pp.465-479
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• 2021

One of the important causes of building and infrastructure failure, such as bridges on pile foundations, is the placement of the piles in liquefiable soil that can become unstable under seismic loads. Therefore, the overarching aim of this study is to investigate the seismic behavior of a soil-pile system in liquefiable soil using three-dimensional numerical FEM analysis, including soil-pile interaction. Effective parameters on concrete pile response, involving the pile diameter, pile length, soil type, and base acceleration, were considered in the framework of finite element non-linear dynamic analysis. The constitutive model of soil was considered as elasto-plastic kinematic-isotropic hardening. First, the finite element model was verified by comparing the variations on the pile response with the measured data from the centrifuge tests, and there was a strong agreement between the numerical and experimental results. Totally 64 non-linear time-history analyses were conducted, and the responses were investigated in terms of the lateral displacement of the pile, the effect of the base acceleration in the pile behavior, the bending moment distribution in the pile body, and the pore pressure. The numerical analysis results demonstrated that the relationship between the pile lateral displacement and the maximum base acceleration is non-linear. Furthermore, increasing the pile diameter results in an increase in the passive pressure of the soil. Also, piles with small and big diameters are subjected to yielding under bending and shear states, respectively. It is concluded that an effective stress-based ground response analysis should be conducted when there is a liquefaction condition in order to determine the maximum bending moment and shear force generated within the pile.

• Journal of Korean Society of Disaster and Security
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• v.15 no.4
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• pp.79-86
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• 2022

The National Park Service is making efforts to create a safe environment by installing rockfall prevention facilities (rockfall prevention nets, fences, and Piam tunnels) in areas at risk of falling rocks. However, the occurrence of falling rocks is increasing every year due to torrential rains caused by climate change, abnormal temperatures in winter, and aging of the ground, and the need to improve the existing rock risk area management plan has emerged. In this study, a pilot area at risk of falling rocks was selected for the Hwanggol district of Chiaksan National Park among Korean national parks, and rockfall analysis was performed using the Rockfall program, and monitoring was conducted by applying a countermeasure method combined with the measurement system to the pilot area. Through this, a rockfall management plan was proposed for continuous management and monitoring of rockfall.

• Earthquakes and Structures
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• v.24 no.5
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• pp.317-331
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• 2023

The buckling-restrained braced frames with eccentric configurations (BRBFECs) are stable cyclic behavior and high energy absorption capacity. Furthermore, they have an architectural advantage for creating openings like eccentrically braced frames (EBFs). In the present study, it has been suggested to use the performance-based plastic design (PBPD) method to calculate the design base shear of the BRBFEC systems. Moreover, in this study, to reduce the required steel material, it has been suggested to use the performance-based practical design (PBPD) method instead of the force-based design (FBD) method for the design of this system. The 3-, 6-, and 9-story buildings with the BRBFEC system were designed, and the finite element models were modeled. The seismic performance of the models was investigated using two suits of ground motions representing the maximum considered earthquake (MCE) and design basis earthquake (DBE) seismic hazard levels. The results showed that the models designed with the suggested method, which had lower weights compared to those designed with the FBD method, had a desirable seismic performance in terms of maximum story drift and ductility demand under earthquakes at both MCE and DBE seismic hazard levels. This suggests that the steel weights of the structures designed with the PBPD method are about 13% to 18% lesser than the FBD method. However, the residual drifts in these models were higher than those in the models designed with the FBD method. Also, in earthquakes at the DBE hazard level, the residual drifts in all models except the PBPD-6s and PBPD-9s models were less than the allowable reparability limit.

• Journal of Hospice and Palliative Care
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• v.13 no.1
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• pp.32-40
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• 2010

Purpose: The survey was aimed to provide basic data to develop a certification system for hospice and palliative care professionals. Methods: National Cancer Center (NCC) and the Korean Society for Hospice & Palliative Care (KSHPC) conducted the survey for hospice and palliative care professionals who worked at 34 Palliative care units designated by the Ministry of Health, Welfare, and Family Affairs (MW) and the members of the KSHPC. The survey was conducted via e-mail from June 17 to 23, 2009. Total 220 professionals were surveyed. Results: Most of the hospice and palliative care professionals reported a great need for certification system: Physician, 90% (n=51) nurse, 84% (n=134) social worker, 89% (n=35). In regard with the requirement for the certification, a majority of physicians (46%) preferreddiploma course, while social workers (46%) preferred training course for medical social workers. Concerning the certification body, physician (45%) preferred the KSHPC and the MW almost equally, while nurses (50%) and social workers (60%) preferred the MW highly. As for the body to develop and accredit advance training course for each professionals, most of the physicians (51%) preferred the KSHPC, whereas nurses and social workers preferred collaboration of the MW (or NCC) with the professional society, such as the KSHPC (23%), the Korean Hospice & Palliative nurses association for nurses (21%), or the Korean association of (medical) social workers (37%). Lastly, all respondents preferred the course format of once a week, full day, and some field study at weekend. Conclusion: Korean hospice and palliative care professionals identified the great need for the certification system, therefore, the adequate system development must be followed to reflect their voice.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.11-18
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• 2012

This study was investigated agricultural water supply system of major agricultural waterway for Gimje canal, Jeongeup canal, Dongjin river conduit of Dongjin river basin. Furthermore, this result will be used for water resources and agricultural demand in Saemangeum reclaimed arable land. Annual precipitation for 5 years in Dongjin river basin was 1,311.7mm. The average discharges in Dongjin river basin was $1,390{\times}10^6\;m^3$ and $1,516{\times}10^6\;m^3$ and $744{\times}10^6\;m^3$ for 2,007 and 2008, respectively. Also, annual average amount of water resources was 1,861${\times}10^6\;m^3$ and $2,279{\times}10^6\;m^3$ and $1,227{\times}10^6\;m^3$ for 2,007 and 2008, respectively. Dongjin river basin water system for the analysis of agricultural water in water resources, runoff, agricultural water demand and usage surveys were analyzed, resulting in the total amount of water due to precipitation of the watershed of the $12.3{\times}10^9\;m^3$ ~$22.8{\times}10^9\;m^3$ and Dongjin River basin in waters flowing discharge is $7.4{\times}10^9\;m^3$~$16.1{\times}10^9\;m^3$, agricultural water demand and usage of each of $6.8{\times}10^9\;m^3$~$6.9{\times}10^9\;m^3$ and $4.9{\times}10^9\;m^3$~$7.1{\times}10^9\;m^3$ compared to the agricultural water demand was more likely. Agricultural water supply system in Dongjin river basin is complex because of devided branches to the main canal and branch canal. In this process, accurately assessment of water usage is very difficult. Therefore, systematic management of water resources and supply of agricultural water supply system to use the terms of the complexity and diversity by considering the appropriate level of agricultural water management systems will be needed. As a result of this study, it can be used water resources assessment in quantity, rational usefulness and basic planning of water resources development for water distribution.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.456-464
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• 2007

This paper proposes a novel three-phase current-fed active clamp DC-DC converter for fuel cells. A single common active clamp branch is used to limit transient voltage across the three-phase full bridge and to realize zero-voltage switching(ZVS) in all switches. To apply for the power generation system current-fed type has been combined with the three-phase power conversion system. The proposed approach has the following advantages: an increase (by a factor of three) of input current and output voltage chopping frequencies; lower RMS current through the inverter switches with higher power transfer capability; reduction in size of reactive later components and the power conditioning system; better transformer utilization; increase of the system reliability. Therefore, the proposed three-phase current-fed active clamp DC-DC converter is appropriate for the boost type DC-DC converter for fuel cells and also applicable for the photovoltaic and battery charge system. The paper details the analysis, simulation and hardware implementation of the proposed system. Finally, experimental results with the proposed PWM strategy demonstrate the feasibility of the proposed scheme on a 500W prototype converter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.93-102
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• 2018

This paper reports a Surge Protective Device (SPD) that is used to protect an automatic metering interface (AMI) power supplies of communication equipment on a low-voltage distribution system from a lightning current. The surge protective device (SPD) can be classified as one-port SPDs and two-port SPDs with decoupling elements depending on the connection type. The protection of internal systems against the lightning current may require a systematic approach consisting of coordinated SPDs. To deal with this, the definition of a lightning protection zone (LPZ) was studied and interpreted through a theoretical review. Because the lightning current resulting from a lightning surge is considerably high, there is limited protection from one SPD; therefore, coordinated cascaded MOV-based SPDs are installed to solve this problem. Regarding the power grid mentioned in this paper, a class II SPD for the low-voltage distribution system installed on the border of LPZ1 and LPZ2, which establish a protection coordination with the Arrester (LA, SA) that corresponds to the LPZO installed on the MOF stage connected to one system were designed to protect various communication (control) equipment, including the automatic meter reading system inside the branch-type electric supply panel of a building, not the incoming side of one system. In addition, performance-related tests were done by a comparison with the existing method through testing, and the optimal design was achieved for the 1-port SPD that uses a series connection and can bleed load current without any decoupling element.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.34-42
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• 2013

In this paper, we compare the performance of wavelet OFDM (Orthogonal Frequency Division Multiplexing) and FD-OFDM(Frequency diversity OFDM) system with conventional OFDM system. Wavelet OFDM system uses wavelet transform rather than Fourier transform and contains intermediate characteristics of CDM (Code Division Multiplexing) and OFDM. In wavelet OFDM system, inter-symbol interference (ISI) can be suppressed effectively and adjacent channel interference can be also minimized well. In FD-OFDM system, each parallel branch symbol is multiplied by the orthogonal sequence and distributed into all sub-carriers. Then, each sub-carrier transmits information composed of the symbol components of all parallel branches in the given frame. FD-OFDM contains the frequency diversity characteristic and, therefore, FD-OFDM can be robust to the narrowband interference. For the comparison among different systems, BER (Bit-Error Rate) performances are evaluated in the presence of narrow-band interference and a harmonic noise channel. From the evaluation results, compared to the conventional OFDM, wavelet OFDM and FD-OFDM shows better robustness against the interference and, especially, wavelet OFDM is the most robust in harmonic noise channel.

• The Journal of Korean Medicine
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• v.32 no.3
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• pp.1-9
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• 2011

Objectives: This study was carried out to observe the foot gworeum meridian muscle from a viewpoint of human anatomy on the assumption that the meridian muscle system is basically matched to the meridian vessel system as a part of the meridian system, and further to support the accurate application of acupuncture in clinical practice. Methods: Meridian points corresponding to the foot gworeum meridian muscle at the body surface were labeled with latex, being based on Korean standard acupuncture point locations. In order to expose components related to the foot gworeum meridian muscle, the cadaver was then dissected, being respectively divided into superficial, middle, and deep layers while entering more deeply. Results: Anatomical components related to the foot gworeum meridian muscle in human are composed of muscles, fascia, ligament, nerves, etc. The anatomical components of the foot gworeum meridian muscle in cadaver are as follows: 1. Muscle: Dorsal pedis fascia, crural fascia, flexor digitorum (digit.) longus muscle (m.), soleus m., sartorius m., adductor longus m., and external abdominal oblique m. aponeurosis at the superficial layer, dorsal interosseous m. tendon (tend.), extensor (ext.) hallucis brevis m. tend., ext. hallucis longus m. tend., tibialis anterior m. tend., flexor digit. longus m., and internal abdominal oblique m. at the middle layer, and finally posterior tibialis m., gracilis m. tend., semitendinosus m. tend., semimembranosus m. tend., gastrocnemius m., adductor magnus m. tend., vastus medialis m., adductor brevis m., and intercostal m. at the deep layer. 2. Nerve: Dorsal digital branch (br.) of the deep peroneal nerve (n.), dorsal br. of the proper plantar digital n., medial br. of the deep peroneal n., saphenous n., infrapatellar br. of the saphenous n., cutaneous (cut.) br. of the obturator n., femoral br. of the genitofemoral n., anterior (ant.) cut. br. of the femoral n., ant. cut. br. of the iliohypogastric n., lateral cut. br. of the intercostal n. (T11), and lateral cut. br. of the intercostal n. (T6) at the superficial layer, saphenous n., ant. division of the obturator n., post. division of the obturator n., obturator n., ant. cut. br. of the intercostal n. (T11), and ant. cut. br. of the intercostal n. (T6) at the middle layer, and finally tibialis n. and articular br. of tibial n. at the deep layer. Conclusion: The meridian muscle system seemed to be closely matched to the meridian vessel system as a part of the meridian system. This study shows comparative differences from established studies on anatomical components related to the foot gworeum meridian muscle, and also from the methodical aspect of the analytic process. In addition, the human foot gworeum meridian muscle is composed of the proper muscles, and also may include the relevant nerves, but it is as questionable as ever, and we can guess that there are somewhat conceptual differences between terms (that is, nerves which control muscles in the foot gworeum meridian muscle and those which pass nearby) in human anatomy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.630-643
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• 2001

In this paper, the performance of a Multi-Carrier DS-CDMA system with Hybrid $SC/MRC- L_{c}/L$ diversity in the multipath Rayleigh fading environment is analyzed and compared with that of a Wideband DS-CDMA system. Each carriers of the number of the input diversity branches in the Multi-Carrier DS-CDMA system is L and among L, the branches of $L_c$ are chosen to be maximum-ratio-combined. And the diversity outputs are coherent-detected and despread by the correlator of each carrier. As the result, we have known that the structure of the Wideband DS-CDMA system with Hybrid $SC/MRC-L_{c}/L$ diversity reception becomes simple due to no synchronization of bit or phase and in terms of the error performance, the performance of Hybrid $SC/MRC- L_{c}/L$ diversity is better than that of selection diversity, but worse than that of MRC diversity. Moreover, the performance of a Multi-Carrier DS-CDMA system is better than that of a Wideband DS-CDMA system in multipath Rayleigh fading channel since Hybrid $SC/MRC- L_c/L$ diversity can obtain gain from each diversity branch. In case four carriers are used and required BER is $10^{-6}$ in wireless data communication, Hybrid SC/MRC-2/4 diversity can increase more 17 users than Hybrid SC/MRC-2/3 diversity because the better input branches can be selected through increase of input branches.