• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.456-462
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• 2014

In this paper, we develop a facility management system which provides fault effect and replacement alarm function of each component for supporting effective maintenance of facility. To do this, we use weighting method to each component, calculate importance of each component, and make them to hierarchy structure using bill of materials of facility. Also, we draw fault cause and fault effect of components based on failure modes effects and criticality analysis, and define criteria of severity, occurrence and detection to get risk priority number. To apply these concepts, we develop and test the facility management system to verify its practicality. In the future, we expect the developed system to apply many domains such as maintenance of ship and offshore plant.

• Journal of the Korea Convergence Society
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• v.6 no.6
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• pp.285-291
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• 2015

FTMS, TCS, ITS equipment such as high-pass highway are just a situation that does not lack traceability and passive surveillance is related to fault DB has so far consisted of an integrated operations management to maximize utilization of the facility. In addition, there is no replacement parts are replaced when a failure occurs, increasing the number of parts and repair time I have trouble growing, and becoming a service interruption whenever you replace each time. In this study, proactively manage the failure history of a highway facility ITS tries to preventive maintenance. Therefore, the error history is based on the reliability of the high-pass facilities theory to calculate the reliability of the system through a systematic statistical analysis Operational Availability. The fault number and the time the replacement period through the estimate decreases and can reduce the budget expenses by securing the spare parts quantity, establish a management plan in part by improving the quality of the system through constant preventive maintenance, quality of service at all times It may direct the non-stop operation state of the available state.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.151-157
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• 2013

The purpose of this study was to examine the toothbrush bristles' wear index and wear rate used by preschool children to provide information on the establishment of criteria for toothbrush replacement cycle for preschool children. One thousand twenty-two toothbrushes were collected from September 20 to November 16, 2012 was analyzed. The findings of the study were as follows: 1. As a result of analyzing the toothbrush wear index, 48.5% of the collected toothbrushes was above 0.400, and the average wear index was $0.421{\pm}0.239$. 2. As a result of analyzing the wear rate of the toothbrushes, score 2 and 3 accounted for 70.4%, and the average wear rate stood at $1.936{\pm}0.848$. 3. As a result of analyzing the state of toothbrush management, the most common average toothbrush replacement cycle was one or two months (63.9%). Concerning the method of toothbrush replacement, the largest group (52.7%) replied they changed toothbrushes based on the abrasivity of toothbrush bristles, and 16.7 percent did that at the request of parents. Given the above-mentioned findings of the study, preschool teachers and parents should be educated to ensure the successful management of preschool children toothbrushes. In addition, it's required to set evident criteria for the right toothbrush replacement cycle for preschool children, and how to provide oral health education in an efficient way should be considered as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.156-163
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• 2020

This study was conducted to provide basic data for realistic applicable changes of sirens by identifying the stress due to the currently used sirens and the need for improving siren. The data was collected from an online survey of 267 subjects who voluntarily agreed to join this study from August 2019 to September, 2019. A structured questionnaire was used as a research tool. The results were analyzed by means and standard deviations, percentages and frequency analysis, and independent t-tests using SPSS. For the current workplace emergency siren type, it is believed that the number of hybrid formats was 143, the most negative opinion of the siren is high at 132, so periodic replacement is needed. For contextual stresses, the highest was 4.35 ± 0.94, when the siren was heard during bedtime. In the stress during sleep, which was based on the daily mean number of movements,, a statistically significant difference was shown between groups of 9 or more movements and below 9 movements (p <0.05). The type of siren paramedics wanted was 'soft music' and 'sound of nature'. More than half of 168 people (62.9%) wanted to replace the current siren, and 163 (91.6%) wanted that periodically within 24 months. Therefore, it is necessary to improve the siren.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.423-432
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• 2014

The aim of this study to propose an efficient method in selecting the type of new and renewable energy applied in at the planning phase of buildings. This study applied geothermal energy facilities with high adaptability to buildings. This study considered the energy reduction and reduced cost by comparing the values with the energy consumption before applying of geothermal energy facilities. In order to propose more reliable criteria of economic evaluation, maintenance costs reflecting the replacement cycles and initial construction costs by drawings and specifications for installation facilities for practical geothermal energy based on construction statement for life-cycle cost analysis. The results will help to effectively select economic types of facilities for new and renewable energy of the planning phase of buildings.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.392-397
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• 1998

PWR 원전의 냉각재 화학 및 체적제어 계통(CVCS) 정화 탈염기는 핵연료에서 방출된 핵분열 생성물질과 방사성 부식생성물을 제거하여 계통 내 방사능 준위를 낮추고, 부식을 유발하는 불순물을 제거하여 계통의 건전성을 유지하며, pH 조절제인 리튬($^{7}$ Li$_3$)의 농도조절을 통해 냉각계 수화학 환경을 최적으로 유지시킨다. 이를 위해 CVCS에는 정화용 혼상 탈염기와 $^{7}$ Li$_3$ 조절용 양이온 탈염기가 설치되었으며, 각각의 탈염기는 독립적인 기능을 수행한다. 이는 원전 운전 중 중성자와 붕소($^{10}$ B$_{5}$ )의 핵반응으로 생성된 $^{7}$ Li$_3$3 의 회수가 불가능하기 때문에 정화 탈염기에는 값비싼 $^{7}$ Li$_3$ 포화형 수지를 충전하여야 한다. Pn 원전은 연료교체를 위해 주기적으로 연료계장전 기간을 갖으며 이에 따라 원자로 기동 수화학, 운전중 B/Li 농도조절에 의한 pH 화학, 원자로 정지화학 등의 주기적인 냉각재 수화학 관리를 해오고 있다. 본 연구에서는 효율적인 정화탈염기의 운영방안을 제시함으로 운전중 붕소의 핵분열로 생성되는 $^{7}$ Li$_3$ 의 회수가 가능하고 수지의 사용량 절감으로 수지폐기물 발생량 저감화를 이를 수 있을 것으로 기대된다.

• Korean Journal of Construction Engineering and Management
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• v.15 no.3
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• pp.113-119
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• 2014

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of structure is rapidly growing unprecedently in engineering practice. Accordingly, in the 21st century, it is almost obvious that life-cycle cost together with value engineering will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, the most researches have only focused on the Deterministic or Probabilistic LCC analysis approach (Level-1 LCC Model) at design stage. Thus, the goal of this study is to develop a practical and realistic methodology for the Lifetime risk based Life-Cycle Cost (LCC)-effective optimum decision-making at design stage.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.321-324
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• 2019

최근 국내에는 실업률 상승, 혼인률 하락 등 청년층 생애주기 변화, 단독거주, 고령층의 증가에 따라 1인 가구가 빠른 속도로 증가하고 있다. 이러한 추세는 지속될 것으로 예상되어 1인 가구를 겨냥한 맞춤형 보안솔루션에 대한 관심이 고조되고 있다. 본 논문에서는 사물 인터넷 기술을 적극적으로 접목할 수 있을 것으로 기대되는 디지털 도어락의 구현에 관한 연구를 수행하였다. 사물 인터넷 기술은 5G 시대의 도래에 따라 다시금 주목받고 있다. 이는 4차 산업혁명 시대의 핵심 기반 기술로 주요 IT 기업들이 상용화 기술 확보를 추진하고 있는 상황이다. 한편 디지털 도어락은 열쇠가 필요하지 않으며 위급상황이나 안전상황에 클릭 한번으로 출동 요원의 출동을 곧바로 요청할 수 있어 고객에게 편의성과 보안성을 제공한다. 하지만 비밀번호 방식의 디지털 도어락은 주기적으로 비밀번호를 교체해주지 않는 이상 지속적으로 같은 자리의 버튼만을 누르게 된다. 이렇게 되면 해당 위치에 지문이 남아서 비밀번호가 노출될 위험이 있다. 그러나 사물 인터넷 기술을 이용한 디지털 도어락을 사용하게 된다면 안전한 도어락 사용으로 주거 보안을 실현할 수 있다. 따라서 1인 가구를 노리는 범죄를 예방하기 위해 라즈베리 파이와 아두이노의 UART 통신, 머신러닝 CV를 이용하여 얼굴 인식으로 동일인임을 판단하는 디지털 도어락을 구현했다.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.66-73
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• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.

• Journal of KIISE
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• v.41 no.11
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• pp.878-884
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• 2014

File I/O buffer cache plays an important role in narrowing the wide speed gap between the main memory and the secondary storage. However, data loss or inconsistencies may occur if the system crashes before the data that has been updated in the buffer cache is flushed to storage. Thus, most operating systems adopt a daemon that periodically flushes dirty data to the secondary storage. In this study, we show that periodic flushes account for 30-70% of the total write traffic to storage and remove this inefficiency by implementing a small, non-volatile buffer cache. Specifically, we present space-efficient management techniques, such as delta-write and fragment-grouping, and show that the storage write traffic and throughput can be improved by a margin of 44.2% and 23.6%, respectively, with only a small NVRAM.