• Journal of the Korean Society for Nondestructive Testing
• /
• v.23 no.3
• /
• pp.227-236
• /
• 2003

Leaks in underground pipelines can cause social, environmental and economical problems. One of relevant countermeasures against leaks is to find and repair of leak points of the pipes. Leak noise is a good source to identify the location of leak points of the pipelines. Although there have been several methods to detect the leak location with leak noise, such as listening rods, hydrophones or ground microphones, they have not been so efficient tools. In this paper, acoustic emission (AE) sensors and accelermeters are used to detect leak locations which could provide all easier and move efficient method. Filtering, signal processing and algorithm of raw input data from sensors for the detection of leak location are described. A 120m-long pipeline system for experiment is installed and the results with the system show that the algorithm with the AE sensors and accelerometers offers accurate pinpointing of leaks. Theoretical analysis of sound wave propagation speed of water in underground pipes, which is critically important in leak locating, is also described.

• 한국연소학회:학술대회논문집
• /
• 2014.11a
• /
• pp.309-310
• /
• 2014

Commercial gas burning appliances are classified by KGS AB338. Even though there are many types of gas appliances with different purposes and uses, common standards are applied to the appliances. Manifold of commercial gas range could often be corroded by salt water. Gas leaks and accidents could be occurred by the corrosion. According to suggestion of detailed material standards for manifold of commercial gas range, it could help to use safely and prevent gas accidents.

• Journal of Environmental Science International
• /
• v.9 no.5
• /
• pp.397-402
• /
• 2000

Numerical simulation model using nesting method and considering topographic features was developed to predict atmospheric environments atmospheric flow temperature and diffusion of air pollutants in Kwangyang bay where having complex areas of point sources Korea. In addition developed simulation model was used tracing of spreading range of pollutants when a gas leaks suddenly from Yeo-cheon industrial complex. by comparing the measured and calculated data on atmospheric flow temperature and diffusion of air pollutants the results showed that this model can be well applied and complicated topography affected the diffusion of air pollutants.

• Proceedings of the KIEE Conference
• /
• 2009.04a
• /
• pp.169-171
• /
• 2009

In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. For development of the environmental-friendly pole transformer using vegetable oil, we discussed the insulation construction of the transformer and the dielectric characteristics of the Nomex insulation paper in vegetable oil. Based on the experimental data, the insulation of the transformer is designed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.10a
• /
• pp.9-10
• /
• 2016

The recent situation in the domestic construction companies with a presence in Singapore and pay a lot of money due to leaks underground structuredefects. Therefore, understanding these root causes and to prevent the construction, and to study the materials, design the improvement plan.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.295-297
• /
• 2003

Cryogenic systems is requirement for the operation of HTS power cables. In general, HTS power cables require temperature below 77K, a temperature that can be achieved from the liquid nitrogen or sub-cooled LN2. HTS power cable is needed for sufficient refrigeration to overcome its low temperature heat loading. This loading typically comes in two forms : (1) heat leaks from the surroundings and (2) internal heat generation. This paper is a explanation for the cooling test of 10m HTS power cable.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.225-226
• /
• 2009

본 연구에서는 신경망과 웨이브릿을 결합하여 플라즈마 챔버의 누출을 감시하기 위한 시계열 모델을 개발하였다. 플라즈마 데이터는 광반사분광기 (Optical Emission Spectroscopy-OES)를 이용하여 측정하였으며, 이를 시계열 신경망을 이용하여 모델링하였다. 이산치 웨이브릿 (Discrete Wavelet Transformation)은 OES 센서정보의 전 처리를 위해 이용되었다. 개발된 웨이브릿 신경망 모델은 47개의 데이터 sets을 이용하여 평가하였으며, 누출상태를 효과적으로 탐지할 수 있었다.

• Fire Science and Engineering
• /
• v.27 no.6
• /
• pp.83-88
• /
• 2013

Catastrophic disasters are sprouting out recently, i.e., the radiation leaks and the hydrofluoric acid gas leaks, etc. The restoration work for these kinds of disasters is very harmful and dangerous for human beings to handle themselves, thus allowing manless robots to fly the reconnaissance planes over to the disaster stricken areas and do the necessary work instead. For this endeavor and purpose, we created and tested an intelligent robot that can inspect those areas, using Mbed (ARM processor) technology temperature sensors and gas sensors aided by CAM (Computer-Aided Manufacturing) cameras. Also, HTTP Server, PC, androids and their combined efforts allow their remote controlled operation from far away with timing control. These intelligent robots can be on duty for 24 hours, minimizing the accidents and crimes and what not, and can respond more quickly when these misfortunes actually happen. We can anticipate the economic effects as well, derived from the reduced needs for hiring human resources.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.6
• /
• pp.503-506
• /
• 2011

Objective : The aim of this study was to assess the safety and efficacy of radiation-sterilized allografts of iliac bone and fascia lata from cadaver specimens to repair skull base defects after transsphenoidal surgery. Methods : Between May 2009 and January 2010, 31 consecutive patients underwent endonasal transsphenoidal surgery and all patients received sellar reconstruction using allografts following tumor removal. The allografts were obtained from the local tissue bank and harvested from cadaver donors. The specimens used in our approach were tensor fascia lata and the flat area of iliac bone. For preparation, allografts were treated with gamma irradiation after routine screening by culture, and then stored at $-70^{\circ}C$. Results : The mean follow-up period after surgery was 12.6 months (range, 7.4-16 months). Overall, postoperative cerebrospinal fluid (CSF) leaks occurred in three patients (9.7%) and postoperative meningitis in one patient (3.2%). There was no definitive evidence of wound infection at the routine postoperative follow-up examination or during re-do surgery in three patients. Postoperative meningitis in one patient was improved with the use of antibiotics and prolonged CSF diversion. Conclusion : We suggest that allograft materials can be a feasible alternative to autologous tissue grafts for sellar reconstruction following transsphenoidal surgery under selected circumstances such as no or little intraoperative CSF leaks.

• Journal of Computing Science and Engineering
• /
• v.5 no.3
• /
• pp.183-196
• /
• 2011

There has recently been a surge of interest in relational database mining that aims to discover useful patterns across multiple interlinked database relations. It is crucial for a learning algorithm to explore the multiple inter-connected relations so that important attributes are not excluded when mining such relational repositories. However, from a data privacy perspective, it becomes difficult to identify all possible relationships between attributes from the different relations, considering a complex database schema. That is, seemingly harmless attributes may be linked to confidential information, leading to data leaks when building a model. Thus, we are at risk of disclosing unwanted knowledge when publishing the results of a data mining exercise. For instance, consider a financial database classification task to determine whether a loan is considered high risk. Suppose that we are aware that the database contains another confidential attribute, such as income level, that should not be divulged. One may thus choose to eliminate, or distort, the income level from the database to prevent potential privacy leakage. However, even after distortion, a learning model against the modified database may accurately determine the income level values. It follows that the database is still unsafe and may be compromised. This paper demonstrates this potential for privacy leakage in multi-relational classification and illustrates how such potential leaks may be detected. We propose a method to generate a ranked list of subschemas that maintains the predictive performance on the class attribute, while limiting the disclosure risk, and predictive accuracy, of confidential attributes. We illustrate and demonstrate the effectiveness of our method against a financial database and an insurance database.