• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.317-322
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• 2003

The Sectional and Spatial failure modes are discussed using the experimental data with long crest wave and multi-directional waves considering the failure modes occurring around the rubble-mound breakwater. The spatial & sectional stability and failure mode around the rubble-mound structures with construction progress can be summarized as follows: 1) The rubble mound structures at basic construction step was occurred serious failures when ${\xi}$ was about 6.5. 2) It was clarified that the failure modes at the round head of detached breakwater are classified as failure by plunging breaking on the slope, failure by direct incident wave force and failure by scouring at the toe of the detached break water. 3) The failure mode was found in the lower wave height than the design wave by the breaker depth effect. 4) The failure on the slope were also developed at the lee side of the round head because diffracted wave propagated into the behind area by grouping effect of multi-directional irregular wave.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.796-808
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• 2019

In this paper, a Smoothed Particle Hydrodynamics (SPH) method is extended to simulate the ice failure process and ice-ship interactions. The softening elastoplastic model integrating Drucker-Prager yield criterion is embedded into the SPH method to simulate the failure progress of ice. To verify the accuracy of the proposed SPH method, two benchmarks are presented, which include the elastic vibration of a cantilever beam and three-point bending failure of the ice beam. The good agreement between the obtained numerical results and experimental data indicates that the presented SPH method can give the reliable and accurate results for simulating the ice failure progress. On this basis, the extended SPH method is employed to simulate level ice interacting with sloping structure and three-dimensional ice-ship interaction in level ice, and the numerical data is validated through comparing with experimental results of a 1:20 scaled Araon icebreaker model. It is shown the proposed SPH model can satisfactorily predict the ice breaking process and ice breaking resistance on ships in ice-ship interaction.

• Proceedings of the Korean Society for Quality Management Conference
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• 한국품질경영학회 2010년도 춘계학술대회
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• pp.435-439
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• 2010

The purpose of this paper is to design a new management model based on the grill-formed product charscteristic area(PCA) which specify the position of products classified by the level of market and technology. This product characteristic area is composed of 9 cells and the cases sorted by market and technology are analyzed by each cell. Conclusion of this study based on many significant results gained by the various multi-variate analysis is summarized as follows; First, it can be noted that success/failure factor and progress stages are different by each cell. Second, a new management model is designed by combining the Motive Resource, Success/Failure(S/F) factors, and Progress Stages of New Product Development. Third, success products featured a balance between marketing oriented and technically oriented activities. A new attemp that combine S/F factors with development stages by each product cell will be of great usefulness for further study.

• Journal of the Korea Concrete Institute
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• 제12권3호
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• pp.67-75
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• 2000

It was well recognized that the damages associated mainly with the aging of civil infrastructures were one of very serious problems for assurance of safety and reliability. Recently carbon fiber sheet(CFS) has been widely used for reinforcement and rehabilitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bending test has been carried out to understand the damage progress and the micro-failure mechanism of CFS reinforced mortars. For this purpose, four different types of specimens are used, that is, mortar, steel bar reinforced mortar, CFS reinforced mortar, and steel bar and CFS reinforced morter. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of specimens. in addition, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for these specimens.

• Journal of Korean Foot and Ankle Society
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• 제13권1호
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• pp.109-112
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• 2009

Calciphylaxis is a rare disease that appear in patients with secondary hyper-parathyroidism or chronic renal failure or that show defect in calcium phosphate metabolism which is characterized by fibrin deposit or calcification of medial wall of vessels causing gradual ischemic skin necrosis. Calciphylaxis is a disease with poor prognosis as skin necrosis can progress rapidly. If left untreated, calciphylaxis will progress to sepsis with high mortality. The treatment is controversial but kidney transplantation or parathyroidectomy is suggested to recover calcium-phosphate metabolism. The authors have experienced calciphylaxis in a patient with chronic renal failure caused by DM nephropathy with characteristic skin lesion and rapid skin necrosis. We describe this case with documentary reviews.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.677-682
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• 1998

Concrete is an inhomogeneous material consisting of larger aggregates and sand embedded in a cement paste matrix. In this study, an acoustic emission technique has been used to clarify the microscope failure mechanisms of concrete under three point bending test. AE source location has also been done to monitor the activities of internal damage and the progress of microscopic failure path during the loading. The relationship between AE characteristic and microscopic and microscopic failure mechanism is discussed.

• Journal of the Korean Society of Safety
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• 제33권3호
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• pp.83-91
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• 2018

This paper suggests a weibull time delay model to evaluate failure risks in FMEA(failure modes and effects analysis). Assuming three types of loss functions for delayed time in failure cause detection, the risk of each failure cause is evaluated as its occurring frequency and expected loss. Since the closed form solution of the risk metric cannot be obtained, a statistical computer software R program is used for numerical calculation. When the occurrence and detection times have a common shape parameter, though, some simple results of mathematical derivation are also available. As an enormous quantity of field data becomes available under recent progress of data acquisition system, the proposed risk metric will provide a more practical and reasonable tool for evaluating the risks of failure causes in FMEA.

• Industrial Engineering and Management Systems
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• 제4권2호
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• pp.192-197
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• 2005

Among many amplitude parameters, Kurtosis (4-th normalized moment of probability density function) is recognized to be the sensitive good parameter for machine diagnosis. Kurtosis has a value of 3.0 under normal condition and the value generally goes up as the deterioration proceeds. In this paper, simplified calculation method of kurtosis is introduced for the analysis of impact vibration with one sided affiliated impact vibration which occurs towards the progress of time. That phenomenon is often watched in the failure of such as bearings’ outer race. One sided affiliated impact vibration is approximated by one sided triangle towards the progress of time and simplified calculation method is introduced. Varying the shape of one sided triangle, various models are examined and it is proved that new index is a sensitive good index for machine failure diagnosis. Utilizing this method, the behavior of kurtosis is forecasted and analyzed while watching machine condition and correct diagnosis is executed.

• Journal of Information Technology Services
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• 제3권2호
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• pp.53-64
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• 2004

For many reasons, SI(Systems Integration) projects can fail. Sometimes, they can result in considerable financial losses to the organizations that undertake them. These projects are abandoned or redirected. However, the cost of project abandonment or redirection can represent a tremendous waste of organizational resources. By managing failure factors carefully, project managers can prevent projects from failing. Types of project failure can be categorized into escalation and de-escalation. Project escalation is that, as projects progress, the project scopes keep increasing. Project de-escalation is that, as projects progress, the project scopes keep decreasing. This study examine relative importance of risk factors that cause project escalation and de-escalation.

• IE interfaces
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• 제19권1호
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• pp.19-25
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• 2006

In the development process, the objective of a reliability growth program is to track the increase in system reliability, and determine as early as possible whether or not the system reliability is growing at a sufficient rate to meet the required goal and allocate available resources accordingly. Implementation of this kind of program will provide very useful information on concept selection, product/process reliability, and cost effectiveness without too much time, money and engineering effort being spent on the development of failure suspect parts. The purpose of this research is to present a practical method for efficiently monitoring a reliability growth test process using AMSAA(Army Materiel Systems Analysis Activity) reliability growth model. The presented growth management is a viable method for identifying failure modes, incorporating design changes and monitoring reliability progress on an on-going basis during the early stages of a product development program.