• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1786-1792
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• 2011

If the concrete track is settled excessively, it must be restored or reinforced immediately. Especially, reinforcement/restoration method should be applied without affecting on train operation. To deal with this problem, special equipment, process and material should be prepared. This paper suggest a special mixing ratio to restore the settled concrete track. Materials are classified the quick hardening mortar and the middle hardening mortar. The quick hardening mortar is used to restore the settled track and the middle hardening mortar is used to fill the void. These materials must have the appropriate gel time(1-40sec) and compressive strength($5kg/cm^2$). Various compounds is used and the micro cement is used as a main base.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1667-1673
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• 2011

For performance evaluation of modified wide sleepers(MF-140 PSC sleepers), design moment for urban transit was calculated and then performance evaluation criteria were set up according to EN 13230-2. Next, static bend tests, dynamic tests at rail seat section of sleeper were carried out and static bend tests at center section of sleeper were fulfilled. The test results for modified wide sleepers were in excess of performance evaluation criteria and structural safety of sleepers was able to guaranteed from the results. As modifying depth of wide sleepers, construction convenience in underground will be expected to be improved and construction costs will be expected to be decreased.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3195-3200
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• 2011

The vibration resulting from railway operation is transmitted through the track and line structure, ground movements to adjacent buildings. As these vibration is growing, there is occurred exaggerated forces and displacements of the track and line structure and it is causing the differential settlement. It is difficult to clarify the dynamic response characteristics of trackbed because of various environmental conditions. However, track irregularity be affected by ununiformed bearing capacity and its dynamic response, study for dynamic response characteristics is required to investigate the cause of track irregularity and countermeasure. This study was intended to evaluate the numerical analysis which exam the response analysis characteristic of ground vibration by shape of cutting and embankment transition zone. The original method of analysis were have to examine variables such as directions, angles, drain conditions, linear conditions. However, In the analysis there were to consider the effect of moving loads according to directions of cutting and embankment transition zone.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.95-101
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• 2012

In this paper, we introduce the automatic speaker identification system 'SPO(Supreme Prosecutors Office) Verifier'. SPO Verifier is a GMM(Gaussian mixture model)-UBM(universal background model) based automatic speaker recognition system and has been developed using Korean speakers' utterances. This system uses a channel compensation algorithm to compensate recording device characteristics. The system can give the users the ability to manage reference models with utterances from various environments to get more accurate recognition results. To evaluate the performance of SPO Verifier on Korean speakers, we compared this system with one of the most widely used commercial systems in the forensic field. The results showed that SPO Verifier shows lower EER(equal error rate) than that of the commercial system.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.46-51
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• 2006

청각 장애인은 집에서 발생하는 여러 가지 소리나 가전 제품의 신호를 감지하지 못하므로 생활의 불편을 상당히 느끼고 있다. 이러한 사람들을 위해 소리 정보를 시각 정보로 변경하여, 사용자들의 시야에 보여주는 것을 목적으로 연구를 시작하였다. 본 연구에서는 집이라는 환경에서 사용자의 위치와 오리엔테이션 정보를 습득하여, 사용자에게 필요한 정보를 시야에 들어오는 범위에 방해되거나 불편하지 않게 표시하는 시스템을 제안한다. 프로젝터에 부착된 카메라를 이용하여 사용자를 인식하고, 사용자를 따라다니며 화면을 디스플레이 하는 기존 방법의 단점들을 해결하기 위해 위치 센서로 사람의 위치와 방향을 파악하여 사용자에게 필요한 정보를 사용자가 현재 바라보는 곳에 디스플레이 하는 방법을 제안한다. 3D 모델로 제작된 집의 구조를 이용하여, 프로젝터의 방향과 초점 제어를 사전에 계산하여 보다 정확한 위치에 정보가 디스플레이 되도록 하였다. 본 논문에서 제안하는 방법이 기존의 PDA 나 PC 모니터를 이용해 정보를 제공하는 방법보다 사용자들이 정보를 인지하는 데 걸리는 시간이 좀더 빠르고 이 방법을 선호하기 때문에, 청각 장애인에게 정보를 제공하는 시스템으로 적합하다는 결론을 도출하였다.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2867-2872
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• 2012

SAN/$BMIPF_6$ nanofibers were fabricated by an electrospinning process and used as chemiresistors for sensing alcohol vapours. A hydrophobic and air-stable ionic liquid, $BMIPF_6$, was used to impart electrical conductivity to insulating SAN nanofibers. The effects of $BMIPF_6$ addition on the morphology of the nanofibers were explained in terms of surface tension, viscosity and conductivity. After exposing the SAN/$BMIPF_6$ nanofibers collected on an interdigitated electrode to alcohol vapours (ethanol, 1-propanol and 1-butanol), the resistance of the nanofibers decreased due to adsorption of alcohol molecules. The electrospun SAN/$BMIPF_6$ nanofibers sensor exhibited good sensitivity and reproducibility.

• Macromolecular Research
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• v.17 no.5
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• pp.307-312
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• 2009

Core-shell hydrogel nanocomposite was fabricated by encapsulating a silica-gold nanoshell (SGNS) with poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-AAc) copolymer. The oleylamine-functionalized SONS was used as a nanotemplate for the shell-layer growth of hydrogel copolymer. APS (ammonium persulfate) was used as a polymerization initiator to produce a hydrogel-encapsulated SGNS (H-SGNS). The amounts of NIPAM (N-isopropylacrylamide) monomers were optimized to reproduce the hydrogel-encapsulated SGNS. The shell-layer thickness was increased with the increase of polymerization time and no further increase in the shell-layer thickness was clearly observed over 16 h. H-SGNS exhibited the systematic changes of particle size corresponding to the variation of pH and temperature, which was originated from hydrogen-bonding interaction between PNIPAM amide groups and water, as well as electrostatic forces attributed by the ionization of carboxylic groups in acrylic acid.

• KCI Concrete Journal
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• v.14 no.3
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• pp.111-120
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• 2002

This study proposes a joint model consisting of different types of members as a new structural system, and then investigates the resulting structural behavior. The joint model consists of a concrete-filled steel tube column (CFT) together with a steel reinforced concrete at the end plus reinforced concrete beam at the center. For comparison, two other joint models were designed, that are, a CPT with a reinforced concrete beam, and a CFT with a steel reinforced concrete at the end plus steel concrete beam at the center, then their joint capacity and rigidity, energy absorption capacity, etc., were all investigated. From the results, the CFT column with a steel reinforced concrete at the end plus steel concrete beam at the center was outstanding in terms of its capacity and rigidity. The results of this analysis demonstrate that an adequate connection type and reinforcement method with different materials of increasing the rigidity, thereby producing a capacity improvement along with protection from pre-fractures.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.135-139
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• 2010

Forensic speaker identification needs high accuracy and reliability. However, the current level of speaker identification does not reach its demand. Therefore, the confidence evaluation of results is one of the issues in forensic speaker identification. In this paper, we propose a new confidence measure of forensic speaker identification system. This is based on pitch differences between the registered utterances of the identified speaker and the test utterance. In the experiments, we evaluate this confidence measure by speech identification tasks on various environments. As the results, the proposed measure can be a good measure indicating if the result is reliable or not.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.274-277
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• 2008

Pohang Wind Energy Research Center (PoWER-C) is developing a 3 MW Radial Flux Permanent Magnet (RFPM) Synchronous Generator for offshore Wind Energy Converter (WEC). The blade rotor rpm is 15.7 and the gear ratio is set to be 92.93. The nominal generator rpm at the rated load is about 1459. Baseline design with surface mounted PM magnets are completed. However, there is some concern about the excessive eddy current heating in the magnets. To alleviate this problem, another design with embedded magnet is going on. With embedded magnets, the generator length should be increased to compensate the increased flux leakage. But the field fluctuation in the magnets due to the slots are greatly reduced. This means less eddy currents and lower magnet operating temperature. In this report, engineering efforts for embedded rotor is presented.