• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.548-549
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• 2014

Omni-directional shear-horizontal magnetostrictive patch transducers have a disadvantage that magnetic flux leakage into the plate when it is installed on a ferromagnetic plate. The leakage produces poor transduction efficiency and unwanted wave mode excitation which should be avoided in guided wave inspections of large plate-like structures. In order to resolve these problems, we newly developed a method to reduce the leakage into the plate. In the method, the patch and the magnet are vertically lifted off and their optimal positions are determined by numerical simulations. Also, the verification of the developed method is successfully verified by experiments.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.160-165
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• 2007

Exhaust manifold is generally subjected to thermal cycle loadings ; at hot condition, large compressive plastic deformations are generated, and at cold condition, tensile stresses are remained in highly deformed critical zones. These phenomena originate from that thermal expansions of the runners are restricted by inlet flange connected to the cylinder head, because the former is less stiff than the latter and, the temperature of the inlet flange is lower than that of the runners. Therefore, due to the repetitions of thermal deformation, leakage problems could be occur between inlet flange and cylinder head. In this study, we obtained pressure distributions along gasket bead lines from the finite element analysis and compared to the test results. It shows a good agreement between numerical and experimental results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.177-180
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• 2006

The accidents of oil leakage is increasing in the Underground Concrete structures for Oil Storege. In the result, the waterproofing in the underground structures is melt down and cannot fulfil its Performance. This study shows an experimental study in the effects of the oil leakage to on the performance of Waterproofing Materials. In order to investigate the actual condition and the problems, a comparative analyses were conducted considering the various types of leakage. Utilizing the obtained results at the basic data for test methods and the standard of quality, we intended to propose a strategy to develop an innovated waterproofing Materials and improve the clean environment of underground structures.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.185-186
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• 2018

Leakage problems in underground spaces of domestic apartments is becoming more serious and legal disputes related to leakage problem have become more commonplace. In this regard, leakage problem is not only a problem in construction, but is also a concern from a societal aspect. In this paper, we propose the details of a below-grade waterproofing design and specification standards of specific areas and sections of residential apartment buildings, and propose that a detailed examination of positive-side waterproofing methods is required.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.217-218
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• 2017

Residential apartment underground structures are being utilized for many purposes such as parking lots, community centers, fitness centers, etc. for efficient use of space. However, there are increasing problems of leakage due to various environmental and deterioration conditions. This paper proposes the development of an information network system which can serve as a base to provide solutions, alternatives and technical information for leakage prevention and effective design at the beginning of the construction stage.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.211-228
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• 2009

After clarifying the underlying problems in a secure network storage, we introduce two important requirements, leakageresilience and availability in higher levels respectively, for data keys that are used to protect remotely-stored data. As a main contribution of this paper, we give a new security layer for overlay networks by proposing a leakage-resilient authentication and data management system. In this system, we specifically propose a single mode and a cluster mode where the latter provides a higher level of both leakage-resilience and availability for the data key.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.3
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• pp.1-6
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• 2012

The containment Integrated Leakage Rate Testing(ILRT) of nuclear power plants in Korea is performed in accordance with NSSC(Nuclear Safety and Security Commission) code 2012-16 and ANSI/ANS 56.8-1994. Nuclear power plants in Korea and the United States are to apply same test criteria, ANSI/ANS 56.8-1994, except type A testing time. NPPs in Korea apply 24 hours according to NSSC code 2012-16, but NPPs in United States apply 8 hours according to 10CFR50 App. J for type A test. So, there are many difficulties in order to perform ILRT in Korea. In this study, I review the impact on the ILRT results and the effect of ILRT due to type A testing time. The future, we will continue study to enhance the test reliability and improve these problems.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.2
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• pp.25-34
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• 2020

As leakage in nuclear power plants could cause a variety of problems, it is very critical to monitor leakage from the safety point of view. Accordingly, a new type of leak detection system is currently being developed and flow characteristics of the sampling and transportation system are investigated by using numerical analysis as a part of the development process in this study. The results showed that the steam mass fraction varied according to the effect of the gap between the insulation and piping component, transportation velocity, and material properties of porous media during the sampling and transportation process. The results of this study should be useful for understanding flow characteristics of the sampling and transportation system and its design and application.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.215-227
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• 2018

As Korea is rapidly becoming an IT powerhouse in the short term, various side effects such as cyber violence, personal information leakage and cyber terrorism are emerging as new social problems. Especially, the seriousness of leakage of personal information, which is the basis of safe cyber life, has been highlighted all over the world. In this regard, it is necessary to estimate the amount of the damage cost due to the leakage of personal information. In this study, we propose four evaluation methods to calculate the cost of damages due to personal information leakage according to average real transactions value, personally recognized value, compensation amount basis, and comparison to similar countries. We analyzed data from 2007 to 2016 to collect personal information leakage cases for 10 years and estimated the cost of damages. The number of cases used in the estimation is 65, and the total number of personal information leakage is about 430 million. The estimated cost of personal information leakage in 2016 was estimated to be at least KRW 7.4 billion, up to KRW 220 billion, and the 10 year average was estimated at from KRW 10.7 billion to KRW 307 billion per year. Also, we could find out the singularity that the estimated damage due to personal information leakage increases every three years. In the future, this study will be able to provide an index that can measure the damage cost caused by the leakage of personal information more accurately, and it can be used as an index of measures to reduce the damage cost due to personal information leakage.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.53-62
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• 2015

Recently, number of tablet or Smartphone users increased significantly in domestic and around the world. But violation of personal information such as leakage, misuse and abuse are constantly occurring by using mobile devices which is very useful in our society. Therefore, in this paper it will talk about the problems in the network environment of the mobile environment such as tablet and Smartphone, Mobile Malware, hacking of the public key certificate, which could be potential threat to mobile environment. This thesis will research for people to use their mobile devices more reliable and safer in mobile environment from invasion and leakage of personal information. In order to use Smartphone safely, users have to use Wi-Fi and Bluetooth carefully in the public area. This paper will research how to use App safely and characteristic of risk of worm and Malware spreading. Because of security vulnerabilities of the public key certificate, it will suggest new type of security certification. In order to prevent from the information leakage and infect from Malware in mobile environment without knowing, this thesis will analyze the improved way to manage and use the mobile device.