• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.37-40
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• 2008

Recently, Construction Business, is changing very quickly, exceedingly needs to slim down the construction expensive by reducing material costs and the term of works. The term of formwork takes 25% of the term of works and costs 15% to 20% of the cost of construction. Hereupon, the purpose of this study is to investigate the Axial Strength of Centrifugall Formed Shell PC Columns that can reduce the term of formwork, the costs of material, the difficulty of throwing away the waste. Shell PC Column is loaded stirrups and manufactured at factory, so it has good points like construction's quality control and part's precision. However, it needs to be tested for checking bonded ability because it is set up at core and coverd with concrete. therefore this study is necessary three type of columns, which are a RC column, different type of two compressive strength core concrete columns and a Shell PC Column. By three columns, this study compare with and analysis three columns's bonded and Compressive Behavior abilities.

• Korean Journal of Construction Engineering and Management
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• v.24 no.4
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• pp.52-59
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• 2023

Flatness inspection of PC elements is normally conducted manually by inspectors at manufacturing sites. However, the manual inspection is error-prone and subjective, so it is necessary to develop a robust and efficient flatness measurement method. Recently, a few studies of laser scanner-based flatness inspection have been conducted. However, little attention on field applicability in terms of accuracy, time and cost has been paid. To tackle the limitation, this study aims to compare three sensing method including floor profiler, terrestrial laser scanner and total station for flatness inspection of PC elements. A series of experiments on two full-scale PC slabs were conducted and the results show that the laser scanning method is the most suitable for the PC elements flatness inspection in the aspects of accuracy, time and cost.

• Korean Journal of Construction Engineering and Management
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• v.25 no.2
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• pp.56-68
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• 2024

A construction standard production rates system for the factory built and on-site installation phases of OSC (Off-Site Construction)-based precast concrete (PC) structures in apartment buildings was recently proposed to establish an objective cost standard (Lee et al., 2021). In addition, the Korean government has taken steps to improve the institutional foundation for the systematic calculation of PC construction costs such as revising construction standard production rates for major components that can be applied to the on-site installation phase of PC method. In this study, we analyzed the results of a field survey of apartment building PC structures and collected expert opinions to develop factory-built and on-site installation standard production rates that can be applied to apartment building PC method. We also propose directions for improving the standard production rates so that they can be applied to the site and component of apartment buildings by comparing them with the current standard production rates. This study also derived the cost characteristics and cost reduction measures of PC construction by calculating the construction costs using the developed rates and comparing the construction costs with the RC methods of apartment buildings of the same scale. The construction standard production rates for PC construction derived in this study are expected to contribute to the spread of PC construction by ensuring the objectivity and consistency of the results of PC methods cost estimation.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.285-290
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• 2013

In a MPC coding using excitation source of voiced and unvoiced, it would be a distortion of speech waveform. This is caused by normalization of synthesis speech waveform of voiced in the process of restoration the multi-pulses of representation section. To solve this problem, this paper present a method of position compensation(PC-MPC) in a multi-pulses each pitch interval in order to reduce distortion of speech waveform. I was confirmed that the method can be synthesized close to the original speech waveform. And I evaluate the MPC and PC-MPC using multi-pulses position compensation method. As a result, $SNR_{seg}$ of PC-MPC was improved 0.4dB for female voice and 0.5dB for male voice respectively. Compared to the MPC, $SNR_{seg}$ of PC-MPC has been improved that I was able to control the distortion of the speech waveform finally. And so, I expect to be able to this method for cellular phone and smart phone using excitation source of low bit rate.

• The KIPS Transactions:PartC
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• v.17C no.4
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• pp.361-370
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• 2010

OTP(One Time Password) is a user authentication using secure mechanism to authenticate each other in a way to generate a password, an attacker could intercept the password to masquerade as legitimate users is a way to prevent attacks. The OTP can be implemented as H/W or S/W. Token and card type OTP, implemented as H/W, is difficult to popularize because of having problem with deployment and usability. As a way to replace it implemented as S/W on Mobile or PC is introduced. However, S/W products can be target of malicious attacks if S/W products have vulnerability of implementation. In fact, FSA said the OTP implemented on a mobile have vulnerability of implementation. However, the OTP implemented on a PC have no case about analysis of vulnerability. So, in this paper derive security review and vulnerabilities analysis of implemented on a PC.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.211-224
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• 2015

Financial companies have invested a lot in their disaster recovery system and exercised training more than once a year to comply related laws and regulations. But massive PCs(Personal Computers) became disrupted simultaneously and it took a lot of time to recover massive PCs concurrently when March 20 cyber attack occurred. So, it was impossible to meet the tartgeted business continuity level. It was because the importance of PC recovery was neglected compared to other disaster recovery areas. This study suggests the measure to recover massive branch terminal PCs of financial companies simultaneously in cost-effective way utilizing the existing technology and tests recovery time. It means that in the event of disaster financial companies could recover branch terminal PCs in 3 hours which is recommended recovery time by regulatory body. Other financial companies operating similar type and volume of branches would refer to the recovery structure and method proposed by this study.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.11-15
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• 2004

This paper deals with EMC filter for a personal computer( PC). A PC contains many sources of noise inside and out, with many connected cables. High noise levels are also emitted from the PC became of high-speed signals. So radiated noise from the computer body may sometimes cause problems. Therefore, we design and fabricate an electromagnetic compatibility (EMC) filter for PC, which is composed of feed-through capacitors and ferrite beads with high permeability. Through extensive test, the proposed EMC filter is shown to have excellent differential-mode and common-mode noises filtering characteristics above 30 dB in the frequency band from 10 MHz to 1.5 GHz. The immunity characteristics are improved more than 10 to 30 dB over the frequency band from DC to 1.8 GHz

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.1-6
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• 2006

In terms of the speed-up of the conventional line, the research for a improved turnout was carried out continually around world. A turnout is known that it is the most unstable equipment structurally in the rail system. So, the turnout is needed more stable structure. An accurate assembly of turnout affects traveling qualify of turnout area and running safety. Therefore, a turnout which is pre-assembled at a factory by using the split PC sleeper is transported to construction site recently in advanced countries. In this paper, the performance measurements which estimate the safety of the split PC sleepers which are adopted for the first time to improve performance of turnout are implemented indoors. The split PC sleeper is one of components of the improved turnout. The test is considered of the worst ballast condition under the maintenance work as like STT(Swithc Tie Tamper) or MTT(Multiple Tie Tamper). These experiments results indicate that structural safety for the expansion joint of the split PC sleepers.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.715-719
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• 2004

This paper deals with EMC filter for a personal computer(PC). A PC contains many sources of noise inside and out, with many connected cables. High noise levels are also emitted from the PC because of high-speed signals. So radiated noise from the computer body may sometimes cause problems. Therefore, we design and fabricate an electromagnetic compatibility (EMC) filter for PC, which is composed of feed-through capacitors and ferrite beads with high permeability. Through extensive test, the proposed EMC filter is shown to have excellent differential-mode and common-mode noises filtering characteristics above 30 dB in the frequency band from 10 MHz to 1.5 GHz. The immunity characteristics are improved more than 10 to 30 dB over the frequency band from DC to 1.8 GHz.

• Journal of Audiology & Otology
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• v.23 no.1
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• pp.53-58
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• 2019

Background and Objectives: The aim of the present study was to assess the feasibility of a PC-based facial asymmetry assessment program (PC-FAAP) and to compare the results of PC-FAAP with subjective regional scoring by raters in acute unilateral peripheral facial nerve paralysis (FNP). Subjects and Methods: Participants were divided into 3 groups with 8 participants per group: group I, normal; group II, mild to moderate FNP; and group III, severe FNP. Using the PC-FAAP, the mouth asymmetry ratio (MAR), eyebrow asymmetry ratio (EAR), and complete eye closure asymmetry ratio (CAR) were calculated by comparing the movement of tracking points on both sides. The FNP grading scale (FGS) integrated each score, and the scores were weighted with a ratio of 5:3:2 (MAR:CAR:EAR). Subjective regional scoring was measured on a 0-100 scale score by three otologists. PC-FAAP and subjective scoring were compared in each group regarding the consistency of the results. Results: The mean scores of the MAR, EAR, CAR, and FGS of each group were significantly different. PC-FAAP showed significant differences between the three groups in terms of MAR, EAC, CAR, and FGS. PC-FAAP showed more consistent results than subjective assessment (p<0.001). The PC-FAAP was significantly more consistent in group I and group III (p<0.001 and p=0.002, respectively). FGS in group III was the only parameter that showed a more consistent result in PC-FAAP than the subjective scoring (p=0.008). Conclusions: An FNP grading system using a PC-based program may provide more consistent results, especially for severe forms.