• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.183-183
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• 2022

최근 몇 년 동안 기후변화에 대응하기 위한 탄소중립 혹은 저탄소 운영의 중요성이 강조되어왔다. 상수도 관망은 직접적인 탄소 배출 시설물은 아니지만, 상수도 관망의 운영 그리고 구성요소의 제조부터 폐기까지의 전 생애주기 동안 막대한 양의 에너지를 사용하는데, 이러한 에너지의사용이 탄소 배출에 간접적인 영향을 주는 것으로 알려져 있다. 특히 수자원공사에 따르면, '17년 기준 수도사업 관련 전기 사용에 따른 간접 배출이 70만tCO2eq에 이르는 것으로 보고되고 있어, 에너지의 효율적인 운영 및 자산관리 체계의 필요성이 커지고 있는 실정이다. 상수도 관망의 에너지 효율에 영향을 주는 요인은 크게 구성요소의 노후와 누수로 구분할 수 있다. 본 연구에서는 상수도 관망 관로 별 노후와 누수 여부를 판단하여 교체 전략을 수립할 수 있는 자산관리 모형을 제안하고 관로별 에너지 효율을 시각화하여 전반적인 자산관리에 근거를 제시하고자 한다. 모형은 최적화 기법을 통한 관로별 기능적 노후도 산정 및 누수 탐지, 관만 내 누수 지역화, 에너지 효율 시각화 등 총 3개의 모듈로 구성되어 있다. 제안한 모형은 고도의 차이가 큰 국내 D시 가상 관망에 적용하였다. 해당 관망에 다양한 관로의 노후 및 누수 상황을 가정하여 가상의 데이터를 생성하고 이를 토대로 관로별 기능적 노후와 누수 조건을 고려하여 해당 모형을 검증한다. 또한, 노후와 누수에 따른 가상 상황별 관로의 자산관리 의사결정 예시를 제공하여 향후 모형의 활용에 대한 가이드 라인을 제시한다. 마지막으로 관망 내 설치된 감압밸브를 터빈으로 전환하여 관망 운영 단계에서 무의미하게 소산되는 열에너지를 회수하는 방안을 검증하였다. 최적화 기법을 통해 비용 대비 최적 터빈 설치 지역을 선정하였고 향후 터빈 설치에 고려해야 할 사항을 정리한다. 본 연구에서의 결과는 향후 종합적인 저탄소형 상수도 관망을 위한 초석을 제공할 것으로 기대한다.

• Smart Media Journal
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• v.12 no.11
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• pp.103-112
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• 2023

Recently, the need to prevent battery fires and accidents has emerged, as the use of lithium-ion batteries has increased. In order to prevent accidents, it is necessary to predict the state of health (SOH) and check the replacement timing of the battery with a lot of degradation. This paper proposes a model for predicting the degradation state of a battery by using four battery degradation indicators: maximum voltage arrival time, current change time, maximum temperature arrival time, and incremental capacity (IC) that can be obtained in the battery charging process, and LSTM using an attention mechanism. The performance of the proposed model was measured using the NASA battery data set, and the predictive performance was improved compared to that of the general LSTM model, especially in the SOH 90-70% section, which is close to the battery replacement cycle.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.203-212
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• 2019

Along with the recent fourth industrial revolution, the world's manufacturing powerhouses are pushing for national strategies to revive the sluggish manufacturing industry. Moon Jae-in, the government is in accordance with the trend, called 'advancement of science and technology is leading the fourth round of the Industrial Revolution' strategy. Intelligent information technology such as IoT, Cloud, Big Data, Mobile, and AI, which are key technologies that lead the fourth industrial revolution, is promoting the emergence of new industries such as robots and 3D printing and the smarting of existing major manufacturing industries. Advances in technologies such as smart factories have enabled IoT-based sensing technology to measure various data that could not be collected before, and data generated by each process has also exploded. Thus, this paper uses data generators to generate virtual data that can occur in smart factories, and uses them to analyze the cause of the defect in real time and to predict the replacement cycle of the facility.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.3
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• pp.1-8
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• 2011

The parking guidance system can increase driver's convenience with detailed parking information service, but it continuously consumes electrical energy with large amount of sensors, displays and control modules. With the increase of the demand for green and sustainable building design, it becomes a meaningful issue for parking guidance system to reduce operating power. This paper presents the preliminary design and estimated results of a parking guidance system which is optimized to reduce the power consumption mainly on detectors and displays. The system design is based on commercial wireless parking detectors, wireless-loop-detector and earth-magnetic-detector. We have performed system architecture design, communication network design, parking information service scenario planning, battery life regulation and at last operating power estimation. With the 7 years of battery replace cycle, the estimated result for power consumption of designed system was 0.33W/slot, which is 13% of the traditional system's estimation result. The estimated annual maintain cost was similar to the traditional ultrasonic sensor based system's. The low power operable designed system can be expected to reduce CO2 emission.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2639-2644
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• 2013

The renewal cycle, which newly decorates stores, has been shortened, as the marketing competition between telecommunication companies has been extended to the stores, due to the rapid increase of mobile phone users and fast replacement cycle of products. The store renewal made by major telecommunication companies, including signboard, has been pushed in order for telecommunication companies to give strong impression about their own brand identity to consumers. Consumers want stores not only to sell cheap and high quality products but also to provide customer experience, by which customers can feel store, product and service and accept them. Especially, since the competition between telecommunication companies is getting tough, it is the current trend that the number of stores is increasing much, and telecommunication companies are recently renewing their stores, with the concept of SI(Store Identity), which changes store image into the incorporated image including interior and exterior, rather than just replacing CI(Corporate Identity), when they renew stores. It can be said that SI(Store Identity) is an important factor, by which companies consistently design visual factors such as interior and sign, and then apply them to the interior and exterior of the stores, and thereby give good store image to consumers, and ultimately have great effect on the increase of sales volume. This kind of activity can be image-controlled by companies' Identity Management, and it can be a very important factor in terms of marketing. In this study, it has an objective to compare and analyze SI of domestic telecommunication companies and foreign telecommunication companies, and then suggest effective SI direction.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.163-176
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• 2005

3개월 동안 사용한 마모된 칫솔의 마모 정도와 양상을 관찰하고, 새 칫솔과 마모된 칫솔의 잇솔질 전 ${\cdot}$ 후 치태제거효율을 single-use design으로 비교 ${\cdot}$ 평가하여 3개월 주기의 칫솔 교체 주기의 근거를 임상적으로 확인 해보고자 하였다. 치주적으로 건강한 치과 대학생 42명을 대상으로 설문지를 통해 잇솔질 습관을 조사하고, 3개월간 동일한 칫솔과 치약을 사용하게 하였다. 3개월 후 피시험자를 무작위로 두 군(I, II)으로 나누고, 치석제거술을 시행한 뒤 2주후에 내원하도록 하였으며 내원 전 48시간동안은 잇솔질을 하지 않도록 지시하였다. 2주후 I군은 새 칫솔을, II군은 마모된 칫솔을 사용하도록 하였으며 잇솔질 전 ${\cdot}$ 후에 각각 구강 내를 erythrosin으로 염색한 후 6개의 Ramfjord 치아의 plaque score를 Patient Hygiene Performance (PHP) index로 측정하였다. 2주간의 washout period 후에 다시 치석제거술을 시행한 뒤, I군이 마모된 칫솔을, II군은 새 칫솔을 사용하게 하여 동일한 방법으로 PHP index를 각각 측정하였다. 마모된 칫솔은 수거하여 brushing surface area의 면적으로 마모도를 평가하였다. 결과는 paired t-test와 Pearson's correlation analysis로 통계처리 하였다. 2명이 탈락하였고 잇솔질 전 ${\cdot}$ 후에 대한 전체 부위, 치간 부위, 변연치은 부위의 plaque score는 두 칫솔 모두 통계학적으로 유의성 있게 감소하였으며 (p<0.0001), 두 칫솔을 비교한 경우에는 새 칫솔이 마모된 칫솔보다 치태 감소량이 통계학적으로 유의성 있게 많았다 (p<0.0001). 칫솔의 마모도는 평균 50.6% 증가하였으며, 마모도 증가에 따른 치태 감소량에는 직선적인 상관관계가 있었으나 통계학적인 유의성은 없었다. (전체 부위 r=-0.58, p=0.72 / 변연치은 부위 r=-0.50, p=0.76). Single-use design에서 3개월 동안 마모된 칫솔은 치태제거 능력에 있어서 새 칫솔보다 덜 효율적이였다. 칫솔의 마모도는 구강 위생 관리에 영향을 미치는 중요한 요인이며, 마모된 칫솔은 정기적인 교체가 요구된다. 또한, 치간 부위를 포함한 변연치은 부위의 치태를 정확하게 평가할 수 있는 치태지수에 대한 연구가 필요하겠다.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.534-546
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• 2023

If the disc cutter is excessively worn or damaged, it becomes incapable of rotating and efficiently cutting rockmass. Therefore, it is important to appropriately manage the replacement cycle of the disc cutter based on its degree of wear. In general, the replacement cycle is determined based on the results of manual inspection. However, the manual measurements has issues related to worker safety and may lead to inaccurate measurement results. For these reasons, some foreign countries are developing the real-time measurement system of disc cutter wear by using different sensors. The ultrasonic sensors, eddy current sensors, magnetic sensors, and others are utilized for measuring the wear amount of disc cutters. In this study, the applicability of eddy current sensors for real-time measurement of wear amount in TBM disc cutters was evaluated. The distance measurement accuracy of the eddy current sensor was assessed through laboratory tests. In particular, the accuracy of eddy-current sensor was evaluated in various environmental conditions within the cutterhead chamber. In addition, the measurement accuracy of the eddy current sensor was validated using a 17-inch disc cutter.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.37-39
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• 1998

This study was carried out to investigate the effects of nutrient solution concentration, irrigation frequency on growth, flowering, and cut flower longevity of Dendranthema grandiflorum (Ramat.) Kitamura 'Shuhouno-chikara' hydroponically grown in perlite media. Not only stem length but also mineral contents of each plant organ in nutrient solution culture were much higher than those in soil culture. 1/2S of nutrient solution was good at early stage, but 1S of nutrient solution was better as chrysanthemum growth progressed. Among different concentrations of nutrient solution, mineral contents of each plant part showed no significant difference. 1S treatment of nutrient solution increased the vase life by 3 days than 2S treatment. The growth and mineral contents of each plant organ were great in plants irrigated 8 times a day, because of high moisture contents of medium and high water availability, followed by more frequent nutrient replenishment near roots. There was no correlation between nutrient solution concentration and vase life of cut flower grown in nutrient solution culture. Cut flowers irrigated twice per day had the longer vase life than other treatments (4, 8 times).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.311-316
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• 2020

The main cause of DMSMS is the rapid replacement cycle and short life cycle of parts, according to the development of science, compared to the long life cycle of weapons systems. In particular, the problem of the supply and demand of such parts becomes even more acute during the operation maintenance phase after the mass production and power generation stage. To eliminate DMSMS problems that arise continuously from development to the operation of weapon systems and select the most cost-effective countermeasures to obsolescence, this paper suggests a standard to determine the appropriate time for quantitative performance improvement by conducting total life cycle cost analysis. For such purpose, this study examined the domestic and overseas cost analysis methods and applied it to single domestic weapon system to verify the research. This study responds to the issue of discontinuing components and helps reduce the total life cycle cost of military products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.110-121
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• 2016

In the decision-making, such as selection of structure, construction method, or time and scheme of maintenance, the evaluation of life-cycle cost(LCC) is of great importance. The maintenance cost occupy a large portion of the LCC of the railway track as well as the initial construction cost. Futhermore, the proportion of the maintenance cost is much higher in the ballasted track. Thus, the importance of the LCC evaluation is higher than in any other engineering structures. In this study, a LCC model that can consider various design parameters such as the type of track structure, annual traffic volume, axle load, train speed, and proportion of curve sections and engineering structures has been developed. Fundamental data for calculating costs also have been presented. Based on the model and data proposed, the trends in the variation of LCC according to the design parameters were examined and the most important design parameters in the LCC analysis of railway track were investigated. The results show that the proportion of renewal and operational costs is much higher in the ballasted track than in the concrete track, and the annual traffic volume and ballast taming period are most significant factors on the LCC of the ballasted track. On the contrary, it is revealed that the proportion of the initial construction costs in the concrete track is much higher, and the LCC of the concrete track is less sensitive to the traffic volume, train speed, and axle load.