• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.49-56
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• 2018

Construction machinery is used to improve productivity in civil engineering work and construction work, and it is a lengthy operation, and consumes considerable fuel to cope with large loads. As a result, productivity and fuel consumption of the construction machine become the main deciding factors. In the hydraulic system of the excavator, the main control valve is the most critical position for control. The flow distribution for control performance is achieved by the metering orifice, that causes critical energy loss. To improve this, we propose a combination of a three port proportional pressure reducing valve and a poppet type flow control valve as an IMV to replace the existing spool type MCV. To validate the proposal, we analyze static characteristics by modeling mathematically, and analyze dynamic characteristics. Simulation using the AMESim software on the regeneration circuit of the boom cylinder up-down operation, verifies the energy-saving effect compared to the existing MCV when IMV is used.

• 한국IT서비스학회지
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• 제11권3호
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• pp.241-255
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• 2012

Recently, smart home environments which provide complex services through smart appliances are becoming realized, due to the advances in connected devices and network technologies. Current smart home environments are mostly restricted, because of difficultly of integration of heterogeneous smart appliances. Therefore radical service integration is impracticable. In this paper, we analyze and implement Machine-to-Machine (M2M) standards which are established by European Telecommunications Standards Institute (ETSI) for integrating heterogeneous devices and services. Smart Home is one of the areas covered by ETSI M2M standards, however these standards are just standardized, so adaption and assessment in smart home are not proved yet. Therefore, this paper analyze ETSI M2M standards by focusing the data transport model and evaluate by selecting the most commonly used smart home scenarios and by implementing ETSI M2M standards compatible smart metering system. In some points ETSI M2M standards are not efficient because of its complexity of structure, however ETSI M2M provides sophisticated features for integrating M2M which are appropriate to adopt diverse smart home environments.

• 상하수도학회지
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• 제31권3호
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• pp.249-256
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• 2017

Recently, application areas based on M2M (Machine-to-Machine communications) and IoT (Internet of Things) technologies are expanding rapidly. Accordingly, water flow and water quality management improvements are being pursued by applying this technology to water and sewage facilities. Especially, water management will collect and store accurate data based on various ICT technologies, and then will expand its service range to remote meter-reading service using smart metering system. For this, the error in flow rate data transmitting should be minimized to obtain credibility on related additional service system such as real time water flow rate analysis and billing. In this study, we have identified the structural problems in transmitting process and protocol to minimize errors in flow rate data transmission and its handling process which is essential to water supply pipeline management. The result confirmed that data acquisition via communication system is better than via analogue current values and pulse, and for communication method case, applying the industrial standard protocol is better for minimizing errors during data acquisition versus applying user assigned method.

• 한국정보통신학회논문지
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• 제26권3호
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• pp.469-478
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• 2022

본 논문은 산업용 생산 장비의 부하 전력을 모니터링하기 위한 스마트 디바이스와 애플리케이션을 개발하고 성능을 평가한 결과를 담고 있다. 스마트 디바이스는 산업용 생산 장비의 부하 전력 및 동작 환경 데이터를 수집해 이를 서버로 전송하는 기능을 가진 스마트 전력 디바이스와 이의 경량화 버전에 해당하는 에너지 미터링 디바이스로 구분해 하드웨어와 더불어 펌웨어를 개발하였다. 이들 디바이스에서 수집한 부하 전력 데이터는 AWS(Amazon Web Services) 서버내 MariaDB에 저장될 수 있도록 하였으며, RESTFul API를 이용해 웹사이트 및 모바일 애플리케이션 상에서 그래프 형태로 부하 전력을 모니터링할 수 있도록 구현하였다. 개발 시스템의 성능을 평가하기 위해 MariaDB에서 웹사이트 및 모바일 애플리케이션까지의 응답 시간을 측정하였으며, 4G(LTE) 네트워크 환경에서는 0.0256~0.0545초, 3G 네트워크 환경에서는 0.6126~1.2978초로 만족스러운 결과를 보여줌을 알 수 있었다.

• 펄프종이기술
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• 제29권3호
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• pp.7-16
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• 1997

The constituents of deposits on paper machine and holes/spots in paper have been studied by consequently a combination of analytical techniques, such as FTIR, Py-GC-MS, and. EDS. FTIR spectroscopy was used prior to Py-GC-MS and EDS analysis, as preliminary analysis technique. The analysis of organic components were carried out with the use of a pyrolysis unit connected to a GC-MS, and inorganic components in ash were analysed by SEM equipped with an EDS analyzer after pyrolysis at 59$0^{\circ}C$. The deposits on the dryer section were complex pitch, which was the mixture of the organic contents of fatty acid ester and starch, and the inorganic contents of talc, clay, and calcium carbonate. The complex pitch was estimated to come from the coated broke. We knew the deposits on the metering rod of sym-sizer were associated with the interaction of unstable AKD and CaCO$_3$. The compositions of holes or spots varied considerably and were associated with chemical interaction within the system. The holes, spots, and blotches in the finished paper were PE and PP that were streamed out from pulp sources, complex pitch that were caused by the interaction of the different additives in the system, polymer such as flexible PVC that used for the prop of palette, and hot melt as adhesives that came from the inadequate handling of broke. In addition, we identified that poly(caprolactam) which is used for forming fabrics or press felts, could be mixed with the raw materials by accident and results in streak on coating.

• 전기전자학회논문지
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• 제23권1호
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• pp.120-126
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• 2019

최근 에너지 인터넷에서 지능형 원격검침 인프라를 이용하여 확보된 대량의 전력사용데이터를 기반으로 효과적인 전력수요 예측을 위해 다양한 기계학습기법에 관한 연구가 활발히 진행되고 있다. 본 연구에서는 전력량 데이터와 같은 시계열 데이터에 대해 효율적으로 패턴인식을 수행하는 인공지능 네트워크인 Gated Recurrent Unit(GRU)을 기반으로 딥 러닝 모델을 제안하고, 실제 가정의 전력사용량 데이터를 토대로 예측 성능을 분석한다. 제안한 학습 모델의 예측 성능과 기존의 Long Short Term Memory (LSTM) 인공지능 네트워크 기반의 전력량 예측 성능을 비교하며, 성능평가 지표로써 Mean Squared Error (MSE), Mean Absolute Error (MAE), Forecast Skill Score, Normalized Root Mean Squared Error (RMSE), Normalized Mean Bias Error (NMBE)를 이용한다. 실험 결과에서 GRU기반의 제안한 시계열 데이터 예측 모델의 전력량 수요 예측 성능이 개선되는 것을 확인한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.160-160
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• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• 한국인터넷방송통신학회논문지
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• 제19권3호
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• pp.17-23
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• 2019

IaaS는 인프라 하드웨어를 소유하지 않고 필요에 따라 임대하는 새로운 방식의 컴퓨팅 서비스로서 비용측면에서 매우 효율적인 것으로 알려져 있다. 일반적으로 사용량에 따른 과금 방식을 채택하므로 인프라 비용에 민감한 서비스를 운영하기에 적합하다. 이러한 서비스를 운영하는 책임자는 예상되는 소요 비용을 조기에 파악하여 클라우드 활용 정책을 적시에 변경하기를 원할 것이다. 그러나 클라우드 서비스 제공자들은 십수시간 지연된 과금 정보를 제공하여 신속한 대처가 불가능하다. 본 논문에서는 가상 머신 인스턴스 수준에서 사용량을 모니터링하고 이에 기반하여 실시간 IaaS 비용 예측 모델을 제안한다. 이 모델 검증을 위하여 1학기 동안의 공용 클라우드 기반의 PC 실습실 서비스를 운용하였으며, 이를 통하여 부과된 실제 금액과의 차이는 평균 5.2% 이하임을 확인하였다.

• 한국인터넷방송통신학회논문지
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• 제22권3호
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• pp.75-81
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• 2022

정부의 배출자 부담 원칙에 따라 배출량에 비례하여 수수료를 차등 부과하는 RFID 기반 음식물류폐기물 종량제가 2012년 전면 시행되었다. 2018년말 기준 전국 149개 지자체, 공동주택 아파트를 기준으로 약 40%의 보급률을 보이고 있다. 장비 도입으로 약 20~30%의 감량 효과가 나타났다. 이와 더불어 기존 장비들에 대한 문제점도 나타나기 시작하였다. 본 연구는 이러한 투입구의 근본적인 문제점의 해결책으로 기존에 나와 있는 기술들을 응용하고 통합하여 개선하고자 하였다. 즉, 음식물쓰레기 종량기 내부의 음식물쓰레기통 안쪽으로 호퍼를 깊숙이 들어가도록 설계를 변경하여 음식물쓰레기가 만수가 되어 수거통 교체 시 원활하도록 고안하여 음식물쓰레기종량기 주변 환경을 개선하고자 한다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.1009-1020
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• 1996

Direct-seeded rice can have comparable yield with transplanted rice if its inherent problems can be solved. It is a labor-saving technology and can significantly reduce production cost because seedling nursery , pulling , and transplanting are omitted. Turnaround time between cropping is reduced hence the possibility of a third annual crop. But direct-seeded rice is very vulnerable to pest attack (by birds, rats, and golden snails), desiccation, weed infestation, and prone to lodging resulting to unstable crop establishment and inconsistent yield. These problems can be solved by anaerobic seeding (sowing pre-germinated seeds under the soil). It requires precise seed placement into the soil to optimize its benefits. We developed a four-row anaerobic direct seeder (US $ 200 commercial price) for this purpose . It consist of a structural framework mounted with a drum -hopper metering device, flotation type drivewheels, spring-loaded and adjustable furrow closers, and furrow open rs, and a plastic rainguard. It can sow in line pre-germinated seeds into the soil thus permitting the use of mechanical weeders for a chemical-free weed control. Its performance was comparable with the Japanese two-row anaerobic seeder (costing US$400) in terms of seed placement and crop establishment. It was tested with five cultivars. Seeding rate varied from 38 kg/ha to 80kg/ha. Crop establishment ranged from 64 to 99 percent while grain yield varied from 3.0 t/ha to 5.4t/ha. A six-row anaerobic seeder was also developed and adapted to a powertiller for increased capacity , field efficiency , and easier operation. The anaerobic seeder is useful to farmers shifting to direct seeding to reduce rice production cost and to researchers conducting agronomic studies in direct-seeded rice. Blueprint of the machine is available free of charge from IRRI.