• Corrosion Science and Technology
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• 제4권4호
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• pp.147-154
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• 2005

The creep resistance of geogrids is one of the most significant long-term safety characteristics used as the reinforcement in slopes and embankments. The failure of geogrids is defined as creep strain greater than 10%. In this study, the accelerated creep tests were applied to polyester geogrids at various loading levels of 30, 50% of the yield strengths and temperatures using newly designed test equipment. Also, the new test equipment permitted the creep testing at or above glass transition temperature($T_g$) of 75, 80, $85^{\circ}C$. The time-dependent creep behaviors were observed at various temperatures and loading levels. And then the creep curves were shifted and superposed in the time axis by applying time-temperature supposition principles. The shifting factors(AFs) were obtained using WLF equation. In predicting the lifetimes of geogrids, the underlying distribution for failure times were determined based on identification of the failure mechanism. The results confirmed that the failure distribution of geogrids followed Weibull distribution with increasing failure rate and the lifetimes of geogrids were close to 100 years which was required service life in the field with 1.75 of reduction factor of safety. Using the newly designed equipment, the creep test of geogrids was found to be highly accelerated. Furthermore, the time-temperature superposition with the newly designed test equipment was shown to be effective in predicting the lifetimes of geogrids with shorter test times and can be applied to the other geosynthetics.

• 한국물환경학회지
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• 제35권6호
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• pp.567-573
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• 2019

DABF(Dissolve Air Flotation with Ball Filter) is developed as the DAF with the addition of a fiber ball at the lower part of the DAF. The DABF with a capacity of 4,500 ㎥/h was constructed at Gijang SWRO plant in Busan. Since the ball filter has high filtration rate, the loading rate of DABF was designed from 20 to 42 ㎥/h/㎡. When one DABF basin is in the back washing mode, the loading rate of other two DABF basins is increased to 42 ㎥/h/㎡. Turbidity at the BF outlet in DABF is <2 NTU at turbidity of 5-10 NTU at the BF inlet. If there is no algae bloom and turbidity is low in raw seawater, only BF in DABF is operated and meets <2 NTU at the BF outlet. Even if BF is operated at high hydraulic loading rates, no significant differential pressure increases and reduction in the turbidity removal rate is minimal in a day. Thus, DABF is the pre-treatment technology that provides stable water quality even with BF onlyoperation without DAF operation. Compared with the DAF, DABF requires additional facilities such as valves, piping, and drainage systems for backwashing the BF. But in terms of footprint and operating costs, DABF has more advantages than DAF. With DABF application, the load of the downstream filtration equipment is decreased so that the capacity of the filtration equipment can be reduced. Also, if the downstream filtration equipment is to be maintained the same regardless of DABF, the operating cost of DABF is less than DAF.

• 토지주택연구
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• 제2권4호
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• pp.569-575
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• 2011

우리나라의 RC 구조물 기계식 해체공사에서는 적절하지 못한 해체장비의 선정과 탑재가 원인이 되어 해체작업 중 구조부재가 붕괴하는 사고가 발생하기도 한다. 따라서 RC 구조물의 기계식 해체공사를 계획할 때 해체공사 담당자가 대상 구조물에 탑재 가능한 장비의 등급을 보다 편리하게 결정할 수 있는 해석기법이 필요한 실정이다. 이 논문에서는 4층 규모 실 구조물을 대상으로 재하실험과 구조해석을 수행하여, 선행연구에서 도출한 RC 구조물에 탑재 가능한 장비 등급의 적정성을 규명하고, 해체공사 담당자가 구조물의 안전성을 편리하게 평가할 수 있는 해석기법을 제안하였다. 이 연구에서 제안한 해석기법은 RC구조물 기계식 해체공사의 작업 안전성과 적정한 장비 운영을 통한 작업 효율성 향상에 유용하게 활용될 수 있을 것으로 사료된다.

• 대한안전경영과학회지
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• 제8권1호
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• pp.1-16
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• 2006

We applied the TPM to loading and unloading equipments of Incheon port and compared with the current maintenance of Incheon port's equipments. Also we analyzed the death disaster causes of equipments and work tools and suggested TPM techniques as a plan of disaster prevention. Using TPM to the loading and unloading equipments we expect to obtain the breakdown zero, defective zero, and disaster zero. And then it should raise the productivity of harbor loading and unloading equipments.

• 한국압력기기공학회 논문집
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• 제12권1호
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• pp.11-16
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• 2016

Fuel assembly's mechanical characterization test facility (FAMeCT) in KAERI was constructed with upgraded functional features such as increased loading capacity, underwater vibration testing and severe earthquake simulation for extended fuel design guideline. This facility is designed and developed to provide out-pile fuel data for accident analysis model and fuel licensing. Functional tests of FAMeCT were performed to confirm functionality, structural integrity, and validity of newly-built fuel assembly mechanical test facility. Test program includes signal check of data acquisition system, load delivering capacity using real-sized fuel assemblies and a standard loading cylindrical rigid specimen. Fuel assembly's lateral bending test was carried out up to 30 mm of pull-out displacement. Limit case axial compression loading test up to 33 kN was performed to check structural integrity of UCPS (Upper Core Plate Simulator) support frame. Test results show that all test equipment and measurement system have acceptable range of alignment, signal to noise ratio, load carrying capacity limit without loss of integrity. This paper introduces newly constructed fuel assembly's mechanical test facility and summarizes results of functional test for the mechanical test equipment and data acquisition system.

• 한국정보전자통신기술학회논문지
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• 제14권1호
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• pp.43-47
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• 2021

본 논문에서는 전력선 통신 (PLC: Power Line Communication) 시스템의 네트워크 데이터 처리량 (throughput)을 구내 (In-building) 환경에서 연구하였다. 전력선 채널은 주파수 선택적 페이딩 주파수 응답을 가지므로 감쇠 및 잡음의 영향을 최소화하기 위해서 adaptive bit loading 방식을 적용한 OFDM (Orthogonal Frequency Division Multiplexing) 변조 방식을 사용하였다. 구내 네트워크의 게이트웨이/CPE (Customer Premise Equipment) 전력선 통신 모뎀 사이의 전력선 통신 구간에서 처리할 수 있는 최대 데이터 처리량을 측정하기 위해 iperf 네트워크 성능 측정 툴을 이용하였고, TCP (Transmission Control Protocol) 윈도우 사이즈별 throughput을 분석하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2002년도 춘계학술대회논문집
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• pp.189-196
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• 2002

As the quantity of transported goods increases, there is a lot of mechanical trouble with loading facilities. So it tremendously produces not only economic loss but also time loss. To reduce the loss from the trouble of leading facilities, it is necessary to analyse the distribution of the problem's occurrence and use the analyzed data to minimize the outbreak of trouble. So the data can be usefully used when designing or manufacturing and it also can be utilized for proper maintenance of operating equipment, frequency of inspection and repair, know-how of checking on equipment and purchasing of spare parts. And it is possible to minimize the loss if the propel maintenance is adapted

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.39-42
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• 2012

Pusher-Loaded Scrapers are important construction equipment for large earthmoving operations. Production rates of a Pusher-Loaded Scraper vary greatly in accordance with the temperature or elevation, the equipment performance, haul speed, haul-road conditions, the method of loading, and Number of scrapers per one pusher. Determining of most economical scrapers fleet regarding the size of equipment, model name, and number of scrapers demands time-consuming calculation because it needs to reference of varied performance charts or tables and repeat complicated calculation. In this study, decision-making support system for the Optimal Pusher-loaded Scrapers Fleet is suggested for the purpose of calculating easily and handling effectively variables which are changed depend of the work conditions. The prototype of this program is developed using MATLAB. And the Database of Pusher-loaded Scraper embodies Performance chart & Retarder chart, soil properties, and calculation-support table.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.246-248
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• 2005

The power plants have a loading dock and unloading device for the diverse kinds of fuel such as the bituminous coal and natural gas imported by the sea from all over the world. To unload the coal in the ship not only in the environment-friendly manner but also in the cost-effective way, the new type of heavy equipment loaded with additional features as well as excavator and the remote controller to maneuver this equipment are developed. This heavy equipment, which can be used to unload the coal in the ship in conjunction with CSU (Continuous Ship Unloader), and the remote controller are endorsed by the related code and laws. With the remote controller, the field workers can operate the unloading equipment at the remote place far from the equipment as well as in the cabin for themselves without tile remote controller.

• 대한안전경영과학회지
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• 제25권4호
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• pp.141-151
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• 2023

Recently, due to the expansion of the logistics industry, demand for logistics automation equipment is increasing. The modern logistics industry is a high-tech industry that combines various technologies. In general, as various technologies are grafted, the complexity of the system increases, and the occurrence rate of defects and failures also increases. As such, it is time for a predictive maintenance model specialized for logistics automation equipment. In this paper, in order to secure the operational safety and reliability of the parcel loading system, a predictive maintenance platform was implemented based on the Naive Bayes-LSTM(Long Short Term Memory) model. The predictive maintenance platform presented in this paper works by collecting data and receiving data based on a RabbitMQ, loading data in an InMemory method using a Redis, and managing snapshot DB in real time. Also, in this paper, as a verification of the Naive Bayes-LSTM predictive maintenance platform, the function of measuring the time for data collection/storage/processing and determining outliers/normal values was confirmed. The predictive maintenance platform can contribute to securing reliability and safety by identifying potential failures and defects that may occur in the operation of the parcel loading system in the future.