• Journal of Biosystems Engineering
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• 제36권2호
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• pp.79-88
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• 2011

The purpose of this study was to analyze power requirement of an agricultural tractor by major field operations. First a survey was conducted to obtain annual usage ratio of agricultural tractor by field operation. Plowing, rotary tillage, and loader operations were selected as major field operations of agricultural tractor. Second, a power measurement system was constructed with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. Third, the major field operations were experimented under fields with different soil conditions following planned operation paths. Power requirement was analyzed during the total operation period consisted of actual operation period (plowing, rotary tillage, and loader operations) and period before and after the actual operation (3-point hitch operating, forward and reverse driving, braking, and steering). Power requirement of tractor major components such as driving axle part, PTO part, main hydraulic part, and auxiliary hydraulic part were measured and calculated to determine usage ratio of agricultural tractor power. Results of averaged power requirement for actual field operation and total operation were 23.1 and 17.5 kW, 24.6 and 19.1 kW, and 14.9 and 8.9 kW, respectively, for plowing, rotary tillage, and loader operations. The results showed that rotary tillage required the greatest power among the operations. Averaged power requirement of driving axles, PTO axle, main hydraulic part, and auxiliary part during the actual field operation were 8.1, 7.8, 3.4, and 1.5 kW, respectively, and the total requirement power was about 70 % (20.8 kW) of the rated power. Averaged power requirement of driving axles, PTO axle, main hydraulic, and auxiliary hydraulic for the total operation period were 6.5, 6.0, 2.1, 0.9 kW, respectively, and total requirement power was about 52 % (15.5 kW) of the rated power. Driving axles required the greatest amount of power among the components.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1397-1405
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• 2017

As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

• 대한조선학회논문집
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• 제55권3호
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• pp.243-251
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• 2018

In the shipyard, a lot of data is generated, stored, and managed during design, construction, and operation phases to build ships and offshore structures. However, it is difficult to handle such big data efficiently using existing data-handling technologies. As the big data technology is developed, the ship and offshore industries start to focus on the existing big data to find valuable information from it. In this paper, the material requirement estimation method of offshore structure piping materials using big data analysis is proposed. A big data platform for the data analysis in the shipyard is introduced and it is applied to the analysis of material requirement estimation to solve the problems in piping design by a designer. The regression model is developed from the big data of piping materials and verified using the existing data. This analysis can help a piping designer to estimate the exact amount of material requirement and schedule the purchase time.

• 한국농공학회논문집
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• 제63권6호
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• pp.61-75
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• 2021

This study aims to assess the changes in crop water requirement of paddy and upland according to future climate and land use changes scenarios. Changes in the spatiotemporal distribution of temperature and precipitation are factors that lower the stability of agricultural water supply, and predicting the changes in crop water requirement in consideration of climate change can prevent the waste of limited water resources. Meanwhile, due to the recent changes in the agricultural product consumption structure, the area of paddy and upland has been changing, and it is necessary to consider future land use changes in establishing an appropriate water use plan. Climate change scenarios were derived from the four GCMs of the CMIP6, and climate data were extracted under two future scenarios, namely SSP1-2.6 and SSP5-8.5. Future land use changes were predicted using the FLUS (Future Land Use Simulation) model. Crop water requirement in paddy was calculated as the sum of evapotranspiration and infiltration based on the water balance in a paddy field, and crop water requirement in upland was estimated as the evapotranspiration value by applying Penman-Monteith method. It was found that the crop water requirement for both paddy and upland increased as we go to the far future, and the degree of increase and variability by time showed different results for each GCM. The results derived from this study can be used as basic data to develop sustainable water resource management techniques considering future watershed environmental changes.

• 한국산학기술학회논문지
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• 제13권9호
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• pp.4207-4213
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• 2012

소프트웨어의 품질은 요구사항 품질과 강하게 관계되어 있다. 이에 따라서 기업들은 요구사항의 품질을 향상시켜 주기 위한 노력을 하고 있다. 그러나 명세서 형태의 요구사항은 검증하기 어려우며, 분석가의 비정형화된 업무 지식에 의존해야 한다. 또한 명세서 형태의 요구사항 품질을 향상시켜 주기 위한 정형화된 방법론이나 자동화된 기법이 미흡한 상황이다. 본 논문에서는 요구사항의 품질을 향상시켜 주기 위한 요구사항 검증 프로세스 및 자동화 검증 도구를 제안한다. 검증을 위해 요구사항에 대한 외적뷰 설계와 내적뷰 설계를 비교한다. 사례연구를 통해 제안된 요구사항 자동화 검증 기법의 타당성을 검증한다.

• 한국생산제조학회지
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• 제19권4호
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• pp.440-448
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• 2010

Recently, there are many corporations, schools and institutes that apply TRIZ to solve technical problems. However, in reality, only a few cases of brainstorming applications exist in utilizing forty principles of TRIZ due to the difficulty at TRIZ problem definition. In order to facilitate TRIZ applications, this study proposes the utilization of requirement definition and description tool of systems engineering in TRIZ problem definition. No requirement definition exists in general problem types that TRIZ approach is used in implementing system solution. At most of problem situations, TRIZ users reversely infer that certain problem belongs to which requirement definition it is and recommends TRIZ tools to be used for the exact problem definition. This study also proposes TRIZ problem definition method by applying the results of requirement definition process. The application of TRIZ is demonstrated to the general situation with no problem definition where the proposed method enables the proper use of TRIZ.

• 한국IT서비스학회지
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• 제8권1호
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• pp.113-124
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• 2009

Value-based requirements engineering process, called The ViRE(Value-Innovative Requirement Engineering) was suggested to create an uncontested market using ERRC(Eliminate, Reduce, Raise, Create) requirements analysis. But ViRE did not provides a quantitative data analysis method for ERRC decision so as to make objective decisions for customers. In this paper, to solve this problem, we suggest a quantitative ERRC analysis method by estimating requirements cost. Our method defines user requirements and decides their weight. Then, it makes quality level table for all the identified requirements and function modules and estimate implementation cost based on their quality levels. Finally, assess each requirement's impact and then evaluate ERRC value. We could get the more objective ERRC values by evaluate the requirement weight. functional module weight, and implementation cost. And we proved the efficiency of our model by a case study, smart student ID system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.121-129
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• 1999

This paper will describe the design of database for system engineering of High Speed Railway Systems, focusing on tile ability to capture a full thread of traceability, from tile inception of a system requirement, to the test results that validate that the designed system meets criteria defined by the requirement. The database includes data models for requirement, function, component, work, work process, resource, etc.. These data models are utilized for tile efficient management of data related system design, development work, and validation.

• Journal of Biosystems Engineering
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• 제28권4호
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• pp.295-304
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• 2003

In this study, a rotary equipped with devices for preventing alien substance from being wound and for preventing soil adherence were developed and their performances are evaluated in the field. The former device was effective in the paddy field with low moisture content, but power requirement of rotary tilling was increased in the field with high moisture content. In the field test of rotaries equipped with device to prevent the power requirements were measured to be 52.18, 52.44, 49.01 and 46.34 PS for general, stainless steel, rubber and PE rotaries, and the quantities of the soil adhered to rotaries, on the average, were to be 5.6, 5.7, 3.1 and 2.7 kg for general, stainless steel, rubber and PE rotaries, respectively. The PE rotary cover reduced the power requirement and soil adherence by 11 and 52%, respectively.

• 수산경영론집
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• 제45권1호
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• pp.33-47
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• 2014

The purpose of this study is to find method to meet the greater retailer's supplier assessment requirement So, this study analyze the greater retailer's requirement for supplier assesment and research global standard which is used instead of supplier assessment requirement that is recognized by global retailers initiative. Next, this study analyze domestic aquaculture certification requirement and compare the global standard with the domestic requirement by using The Most Similar Systems Design. As a result, this comparing has founded all of two domestic certifications are similar to global standard's Good Aquaculture Practice module but those are a little bit different from System Element module. Therefore, this study suggest tree alternative. First, make up for the weak points in the current domestic aquaculture certification system. Second, the introduction of global aquaculture management system certification as supporting by government. Third, development of new standard in accordance with global food standard. This study has major implications for research into development of domestic aquaculture standard.