• Geomechanics and Engineering
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• 제18권1호
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• pp.1-9
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• 2019

In this study, both 2D and 3D failure shapes of rock mass above the water-filled cavity are put forward when the surrounding rock mass cannot bear the pressure caused by the water-filled cavity. Based on the analytical expressions derived by kinematic approach, the profiles of active and passive failure patterns are plotted. The sensitivity analysis is conducted to explore the influences of different rock parameters on the failure profiles. During the excavation of the deep tunnels above the karst cavity, the water table always changes because of progressive failure of cavity roof. Therefore, it is meaningful to discuss the effects of varying water level on the failure patterns of horizontal rock layers. The changing laws of the scope of the failure pattern obtained in this work show good consistency with the fact, which could be used to provide a guide in engineering.

• International Journal of Reliability and Applications
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• 제10권1호
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• pp.1-15
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• 2009

Even though the impact of manufacturing quality to reliability is not considered much as well as that of design area, a major cause of an early failure of the product is known as manufacturing problem. This research applies two different types of neural network algorithms, the Back propagation (BP) algorithm and Learning Vector Quantization (LVQ) algorithm, to identify and classify the nonrandom variation pattern on the control chart based on knowledge-based diagnosis of dimensional variation. The performance and efficiency of both algorithms are evaluated to choose the better pattern recognition system for auto body assembly process. To analyze hundred percent of the data obtained by Optical Coordinate Measurement Machine (OCMM), this research considers an application in which individual observations rather than subsample means are used. A case study for analysis of OCMM data in underbody assembly process is presented to demonstrate the proposed knowledge-based pattern recognition system.

• 사상체질의학회지
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• 제26권3호
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• pp.262-271
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• 2014

Objectives This research was proposed to present Clinical Practice Guideline(CPG) for Soyangin Disease of Sasang Constitutional Medicine (SCM) ; Chest-Heat congested(Hyunggyeok-yeol) Symptomatology. Methods This CPG was developed by the national-wide experts committee consisting of SCM professors. First, collection and organization of literature related to SCM such as Donguisusebowon, Text book of SCM, Clinical Guidebook of SCM and Fundamental research to standardize diagnosis of Sasang Constitutional Medicine was performed. Secondly, journals related to clinical trial or Human complementary medicine of SCM were searched. Finally, 4 articles were selected and included in CPG for Chest-Heat congested(Hyunggyeok-yeol) Symptomatology of Stomach Heat-based Interior Heat disease in Soyangin disease. Results & Conclusions CPG of Chest-Heat congested(Hyunggyeok-yeol) symptomatology in Soyangin disease includes classification, definition and standard symptoms of each pattern. Chest-Heat congested(Hyunggyeok-yeol) symptomatology is classified into mild and moderate pattern by severity. Chest-Heat(Hyunggyeok-yeol) symptomatology Mild pattern is classified into Chest-Heat congested(Hyunggyeok-yeol) initial pattern and Chest-Heat congested(Hyunggyeok-yeol) advanced pattern. And Chest-Heat congested (Hyunggyeok-yeol) moderate pattern is classified into Clear Yang Failure of Stomach(Weguck-cheongyang Bulsagnseung) pattern (Upper wasting-thirst(Sangso) pattern), Clear Yang Failure of Large Intestine (Daejang-cheongyang Bulsangseung) pattern (Middle wasting-thirst (Jungso) pattern).

• Geomechanics and Engineering
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• 제24권1호
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• pp.81-89
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• 2021

Uniaxial compression tests were conducted on sandstone-CGFB composite samples with different interface angles, and their strength, acoustic emission (AE), and failure characteristics were investigated. Three macro-failure patterns were identified: the splitting failure accompanied by local spalling failure in CGFB (Type-I), the mixed failure with small sliding failure along with the interface and Type-I failure (Type-II), and the sliding failure along with the interface (Type-III). With an increase of interface angle β measured horizontally, the macro-failure pattern changed from Type-I to Type-II, and then to Type-III, and the uniaxial compressive strength and elastic modulus generally decreased. Due to the small sliding failure along with the interface in the composite sample with β of 45°, AE events underwent fluctuations in peak values at the later post-peak failure stage. The composite samples with β of 60° occurred Type-III failure before the completion of initial compaction stage, and the post-peak stress-time curve initially exhibited a slow decrease, followed by a steep linear drop with peaks in AE events.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.202-207
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• 2016

Purpose: The purpose of this study is main factors (environmental conditions, pattern spacing, pattern material) that effect the ion-migration of PCB. Methods: Recently, the electronic components are becoming more high density of electronic device, so that electronic circuits have smaller pitches between the patten and more vulnerable to insulation failure. so the reliability of electric insulation of device has become an ever important issue as device contact pitches of pattern. Usually, ion-migration occurs in high temperature and high humidity environment as voltage is applied to the circuit. Under high temperature and high humidity, voltage applied electronic components respond to applied voltages by metals's electrochemical ionization and a conducting filament forms between the anode and cathode across a nonmetallic medium. This leads to short-circuit failure of the electronic component. Results: we studied ion-migration that occurs in accordance with the main factors (environmental conditions, pitches, pattern material). The PCB pattern material was made by two different types of material (free solder, OSP) for this research and pitches of pattern is 0.15mm, 0.3mm, 0.5mm. PCB was experimented in the environmental conditions (high temperature $120^{\circ}C$, high temperature and high humidity $85^{\circ}C$, 85%RH) and was analyzed for ion-migration through the experiment results. Conclusion: We confirmed that environmental condition, pitches of pattern, pattern material had effect on ion-migration of PCB.

• 한국전자파학회논문지
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• 제25권2호
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• pp.217-222
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• 2014

본 논문에서는 평면형 능동 위상 배열 안테나에서 일부 모듈의 고장이 발생할 경우, 발생되는 빔 패턴 왜곡을 여러가지 경우로 비교하여 검토하고, 기존에 연구된 빔 패턴 보상 방법을 실제 안테나에 적용하여 빔 패턴 왜곡 개선 가능성을 분석하였다. 빔 패턴의 왜곡은 주로 부엽 수준의 증가로 나타나게 되는데, 부엽 수준이 기준치를 넘어서게 되면 고장모듈을 제외한 나머지 모듈의 크기/위상값을 재조정하여 부엽을 낮출 수가 있으며, 본 논문에서는 이 방법을 실제 제작된 안테나에 적용하기 위한 방안 및 근접 전계 챔버에서 측정한 결과를 시뮬레이션 결과와 비교하여 나타내었다. 고장모듈이 발생하는 경우는 무작위로 여러 곳에서 발생하는 경우와 여러 개의 배열을 포함하는 단위 모듈이 고장 날 경우로 나누어서, 시뮬레이션 결과와 측정 결과를 비교 분석하였다. 측정 결과는 시뮬레이션 결과와 유사한 경향을 나타내며, 고장 모듈이 발생할 경우 남아있는 정상 모듈의 크기/위상 조정을 통해서 부엽을 낮추기 위한 빔 패턴 보상이 가능함을 확인할 수 있다.

• Smart Structures and Systems
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• 제30권1호
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• pp.49-62
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• 2022

Experimental and discrete element methods were used to investigate the effects of triple joints lengths and triple joint angle on the failure behavior of rock mass under uniaxial compressive test. Concrete samples with dimension of 20 cm × 20 cm × 5 cm were prepared. Within the specimen, three imbedded joint were provided. The joint lengths were 2 cm, 4cm and 6 cm. In constant joint lengths, the angle between middle joint and other joints were 30°, 60°, 90°, 120° and 150°. Totally 15 different models were tested under compression test. The axial load rate on the model was 0.05 mm/min. Concurrent with experimental tests, the models containing triple joints, length and joint angle are similar to the experiments, were numerical by Particle flow code in two dimensions (PFC2D). Loading rate in numerical modelling was 0.05 mm/min. Tensile strength of material was 1 MPa. The results show that the failure behaviors of rock samples containing triple joints were governed by both of the angle and the length of the triple joints. The uniaxial compressive strengths (UCS) of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. Furthermore, it was shown that the compressive behavior of discontinuities is related to the number of the induced tensile cracks which are increased by decreasing the joint length. Along with the damage failure of the samples, the acoustic emission (AE) activities are excited. There were only a few AE hits in the initial stage of loading, then AE hits rapidly grow before the applied stress reached its peak. In addition, every stress drop was accompanied by a large number of AE hits. Finally, the failure pattern and failure strength are similar in both methods i.e., the experimental testing and the numerical simulation methods.

• Computers and Concrete
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• 제26권3호
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• pp.239-255
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• 2020

Experimental and discrete element method were used to investigate the effects of joint number and its angularities on the shear behaviour of joint's bridge area. A new shear test condition was used to model the gypsum cracks under shear loading. Gypsum samples with dimension of 120 mm×100 mm×50 mm were prepared. the length of joints was 2cm. in experimental tests, the joint number is 1, 2 and 3 and its angularities change from 0° to 90° with increment of 45°. Assuming a plane strain condition, special rectangular models are prepared with dimension of 120 mm×100 mm. similar to joints configuration in experimental test, 9 models with different joint number and joint angularities were prepared. This testing show that the failure process is mostly governed by the joint number and joint angularities. The shear strengths of the specimens are related to the fracture pattern and failure mechanism of the discontinuities. The shear behaviour of discontinuities is related to the number of induced tensile cracks which are increased by increasing the rock bridge length. The strength of samples decreases by increasing the joint number and joint angularities. Failure pattern and failure strength are similar in both of the experimental test and numerical simulation.

• Radiation Oncology Journal
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• 제7권1호
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• pp.45-50
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• 1989

From Feb.1985 to Feb.1988,76 patients with squamous cell carcinoma of the lung treated at the Department of Therapeutic Radiology in Kyungpook National University Hospital were available for the analysis of this study. All patients received radiation of 4000cGy-6600cGy with curative aim. The overall rate of complete response was 25.0% and partial response was 452.6% The complete and partial regression of tumor was 14.3% in patients treated with dose below 5000cGy and 84.1% in the group treated with dose above 5000cGy (p<0.01). The complete response was seen only in the group of patients received radiation at least 6000cGy. The patterns of failure were as follows. The rate of initial intrathoracic recurrence was 52.6% in patients with complete response. The overall rate of failure was 68.8%. Distant metastasis was found in 47.4% of patients. Bone, contralateral lung, and brain were common metastatic sites in decreasing order All of the distant metastases and 80% of local recurrences were found within the first year after treatment.

• 한국소음진동공학회논문집
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• 제21권2호
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• pp.146-153
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• 2011

Model based machine condition diagnosis methods are generally using a normal and many failure models which need sufficient data to train the models. However, data, especially for failure modes of interest, is very hard to get in real applications. So their industrial applications are either severely limited or impossible when the failure models cannot be trained. In this paper, continuous hidden Markov model(CHMM) with only a normal model has been suggested as a very promising machine condition diagnosis method which can be easily used for industrial applications. Generally hidden Markov model also uses many pattern models to recognize specific patterns and the recognition results of CHMM show the likelihood trend of models. By observing this likelihood trend of a normal model, it is possible to detect failures. This method has been successively applied to arc weld defect diagnosis. The result shows CHMM's big potential as a machine condition monitoring method.