• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.835-838
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• 2008

In this study, long-term compression displacement of damping materials used to reduce floor impact noise and compressive load that crack begins to happen in Ondol layers including the material were measured as basic research to make guide line for right choice of damping material considering structural stability of Ondol layer. From the result, it was found that compression displacement by elapsed time as well as early displacement of damping material when load is applied on Ondol layer are should be included in the guide line for the choice of damping materials. And no problem is expected to be in structural stability of Ondol layer in case choose a damping material that compression displacement at three months later from inflict load is within 10% than initial thickness.

• 한국지반공학회논문집
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• 제30권2호
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• pp.53-64
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• 2014

이 연구에서는, 균질한 재성형 점토를 이용한 실내시험을 통해 정규압밀 영역에서의 하중재하기간이 점성토의 압축 및 장기압밀 특성에 미치는 영향을 명확히 하고자 하였다. 또한 각 하중재하기간에 따른 현장에서의 유효상재하중에 해당하는 초기압밀하중을 변화시킨 장기압밀 시험을 수행하여 표준압밀시험시의 하중단계별 재하방법과 하중재하기간의 증가에 따른 압축곡선의 특성을 비교/분석하여 하중재하기간에 따라 최종침하량을 예측하는 방법을 제안하고자 하였다. 연구 결과 하중재하기간에 따른 점성토의 압축특성은 초기압밀하중을 가한 후 하중재하기간이 증가할수록 주어진 단계에서의 압밀후반부의 2차압밀의 증가로 선행압밀하중이 약간씩 감소하는 경향을 나타내었다. 그와 동시에 2차압밀이 유사과압밀 현상 및 점토골격의 안정화를 유발하여 정규압밀영역에서의 압축지수에 미치는 영향은 미미했으며 과압밀영역에서는 유사과압밀 현상으로 재압축지수의 증가를 유발하는 것으로 나타났다.

• 한국지반공학회지:지반
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• 제14권2호
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• pp.21-30
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• 1998

쓰레기 매립지는 쓰레기 고형물이 장기간에 걸쳐 생물학적으로 분해됨으로 말미암아 상당한 양의 침하가 유발되는 독특한 침하특성을 갖고 있다. 분해에 의한 총 압축량은 분해가능한 쓰레기의 고형물 함량 및 매립연한에 크게 의존하며. 매립지 침하의 안정화 속도는 분해조건에 의존한다. 쓰레기 매립지의 이러한 독특한 침하거동을 규명하기 위하여 제안되었던 침하모델을 매립 연한이 서로 다른 쓰레기 매립지 침하자료들에 대하여 적용하였다. 모델 변수 값들이 각각 구해 졌으며, 그 경향들이 분석되었다. 쓰레기 매립지의 장기 침하 양상이 제안된 모델에 의해 잘 예측될 수 있으며, 매립연한 및 두개의 적합한 설계변수에 근거하여 잔존 침하량을 예측할 수 있다.

• Geomechanics and Engineering
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• 제17권2호
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• pp.215-225
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• 2019

The mechanical behavior of rock is essential to estimate the capacity and long-term stability of $CO_2$ storage in deep saline aquifers. As the depth of reservoir increases, the pressure and temperature that applied on the rock increase. To answer the question of how the confining pressure and temperature influence the mechanical behavior of reservoir rock, triaxial compression experiments were carried out on brine-saturated sandstone at elevated temperature. The triaxial compressive strength of brine-saturated sandstone was observed to decrease with increasing testing temperature, and the temperature weakening effect in strength enhanced with the increase of confining pressure. Sandstone specimens showed single fracture failures under triaxial compression. Three typical regions around the main fracture were identified: fracture band, damaged zone and undamaged zone. A function was proposed to describe the evolution of acoustic emission count under loading. Finally, the mechanism of elevated temperature causing the reduction of strength of brine-saturated sandstone was discussed.

• Journal of Korean Neurosurgical Society
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• 제65권5호
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• pp.615-621
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• 2022

Various treatments for trigeminal neuralgia (TN) are known to yield initial satisfactory results; however, the surgical treatment has excellent long-term outcomes and a low recurrence rate. Surgical treatment addresses the challenge of vascular compression, which accounts for 85% of the causes of TN. As for surgical treatment for TN, microvascular decompression (MVD) has become the surgical treatment of choice after Peter J. Jannetta reported the results of MVD surgery in 1996. Since then, many studies have reported a success rate of over 90% for the initial surgical treatment. Most MVDs aim to separate (decompress) the culprit vessel from the trigeminal nerve. To increase the success rate of surgery, accurate indications for MVD and management of the offender vessels without complications are critical. In addition, if there is no vascular compression, partial sensory rhizotomy or internal neurolysis can be performed to improve surgical outcomes.

• Journal of Communications and Networks
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• 제18권1호
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• pp.95-104
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• 2016

Massive multiple-input multiple-output (MIMO) is a promising approach for cellular communication due to its energy efficiency and high achievable data rate. These advantages, however, can be realized only when channel state information (CSI) is available at the transmitter. Since there are many antennas, CSI is too large to feed back without compression. To compress CSI, prior work has applied compressive sensing (CS) techniques and the fact that CSI can be sparsified. The adopted sparsifying bases fail, however, to reflect the spatial correlation and channel conditions or to be feasible in practice. In this paper, we propose a new sparsifying basis that reflects the long-term characteristics of the channel, and needs no change as long as the spatial correlation model does not change. We propose a new reconstruction algorithm for CS, and also suggest dimensionality reduction as a compression method. To feed back compressed CSI in practice, we propose a new codebook for the compressed channel quantization assuming no other-cell interference. Numerical results confirm that the proposed channel feedback mechanisms show better performance in point-to-point (single-user) and point-to-multi-point (multi-user) scenarios.

• 한국정밀공학회지
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• 제29권1호
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• pp.96-102
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• 2012

The current establishment of car engineering plastic piping polyethylene (PE) tube used as bonding state or part of the health or safety of fusion is very important. A part of these fusion methods to determine the soundness of the short-term trials and long-term tests can be largely classified. Typical tests included short-term strength, tensile strength, impact strength, compressive strength, resiliency and compression. Polyethylene (PE) pipes installed in the domestic terms of overall penetration rate of 45% has been used. However, polyethylene (PE) pipes have reliability problems, and these occurs mostly in part by defective welding. Therefore, the test is necessary for safety. Non-destructive methods (ultrasonic testing) are difficult to be used. Therefore, Polyethylene (PE) pipe are used. Fusion of thses materilas is necessary in these field however, its technical, and basic research has not been studied well. In this research, short-term strength of welding parts, its tensile strength, hardness, fatigue, and microstructure have been analyzed to find the optimum process conditions to improve mechanical properties.

• 한국생산제조학회지
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• 제20권5호
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• pp.564-569
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• 2011

The current establishment of city gas piping polyethylene (PE) tube used as bonding state or part of the health or safety of fusion is very important. A part of these fusion methods to determine the soundness of the short-term trials and long-term tests can be largely classified. Typical tests include short-term strength, tensile strength, impact strength, compressive strength, resiliency and compression. Polyethylene (PE) pipes installed in the domestic terms of overall penetration rate of 45% has been used. However, polyethylene (PE) pipes have reliability problems, and these occurs mostly in part by defective welding. Therefore, the test is necessary for safety. Non-destructive methods (ultrasonic testing) are difficult to be used. Therefore, Polypropylene copolymer (PP-C), polypropylene homopolymer (PP-H), and polyethylene (PE) pipe are used. Fusion of these materials is necessary in these field however, its technical, and basic research has not been studied well. In this research, short-term strength of welding parts, its tensile strength, hardness, fatigue, and microstructure have been analyzed to find the optimum process conditions to improve mechanical properties.

• 한국지진공학회논문집
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• 제13권1호
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• pp.53-60
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• 2009

지진격리 구조물은 하부구조에서 상부구조로 전달되는 지진력의 현저한 감소가 요구되는 경우 고감쇠 고무받침(HDRB)과 같은 지진격리받침을 사용하는 구조물로서 내진설계의 도입 이후부터 많이 설계, 시공되고 있다. 적층고무받침은 지진격리장치에서 가장 중요한 구조부재이다. 적층형 고무받침의 기본 특성은 압축시험, 압축전단시험, 크리프시험 등을 통하여 얻는 것이 일반적이다. 본 연구에서는 축 응력 7.5MPa, 8.37MPa인 지진격리받침(고감쇠 고무받침)을 실물크기로 제작하여 실험실에서 1000시간동안 크리프 시험을 실시하였다. 고감쇠 고무받침과 같은 지진격리받침을 실제 교량환경 상태에서 장기간 압축 크리프 시험한 결과 1000시간 후 최대크리프 변형은 전체 고무두께의 $0.3{\sim}1.92%$로 변형하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권1호
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• pp.31-38
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• 2013

Patients with heart disease need long-term monitoring of the electrocardiogram (ECG) signal using a portable electrocardiograph. This trend requires the miniaturization of data storage and faster transmission to medical doctors for diagnosis. The ECG signal needs to be utilized for efficient storage, processing and transmission, and its data must contain the important components for diagnosis, such as the P wave, QRS-complex, and T wave. In this study, we select the vertex which has a larger curvature value than the threshold value for compression. Then, we reconstruct the compressed signal using by radial basis function interpolation. This technique guarantees a lower percentage of root mean square difference with respect to the extracted sample points and preserves all the important features of the ECG signal. Its effectiveness has been demonstrated in the experiment using the Massachusetts Institute of Technology and Boston's Beth Israel Hospital arrhythmia database.