• 상하수도학회지
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• 제20권1호
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• pp.44-52
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• 2006

Bio-filtration processes using honeycomb tubes (process 1) and aeration and manganese-sand filtration (process 2) were evaluated for the biological manganese removal efficiency. The concentration of manganese at effluent was stabilized after 20days operation in process 1. It was estimated the required time for attaching and growing microorganisms to honeycomb tubes. In long term of operation periods, manganese removal efficiency was dropped for the excessively attached biofilm and manganese dioxide to honeycomb tubes. It took several days for normal operation in process 2, after that manganese removal efficiency was increased to 98% and stabilized for 1.5 years. Microorganisms in process 1 and 2 were isolated and cultured to characterize manganese-oxidizing bacteria. Among the four types of colony, light brown colony was turned blue color by leuco crystal violet spot test. Stenotropomonas genus, known as manganese-oxidizing bacteria, was identified by 16S rDNA partial sequencing analysis which was isolated in process 1 and 2. For the biological treatment to remove manganese, these two considerations are important. One is to choose the proper media attaching manganese oxidant, another one is to define the cultural condition of isolated manganese-oxidizing bacteria.

• 한국기계가공학회지
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• 제12권5호
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• pp.102-108
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• 2013

In this study, the experiment result and numerical analysis on temperature distribution of a secondary battery module for high temperature operation type were compared. Because experimental battery has been in danger of explosions, experiment on temperature distribution was carried out using dummy batteries. Study on NAS battery module, which is secondary battery of high temperature operation type, is as follows ; Test result showed that battery's temperature is in steady state uniformly after 8 hours in each section. It is similar to experimental result for temperature distribution from the result of numerical analysis, and it takes about 8.5 hours to the $300^{\circ}C$.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.32-39
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• 1997

The coiling station of ISP coil box is an equipment that winds a hot bar rolled at reduction unit into a coil without mandrel. In the coiling process, the roll gap of the bending unit is a significant one of several factors that influence bar coiling. To obtain a good bar-coil, the roll gap must be set appropriately according to the bar thickness. In this study, with 2-dimensional isothermal elastic-plastic finite element method, authors investigated influence of the change of the roll gap on the initial coiling shapes and the formed inner diameters of coils. Based on finite element analysis, authors proposed the appropriate roll gap according to the bar thickness to be able to wind a hot bar. The inner diameters of coils by results of analysis comparatively agreed with coling operation conducted in plant.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.147-152
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• 2005

The exhaust system of automobile is faced with random or spectrum types of fatigue loads during usage life and so needs to be closely estimated for quality and performance to have enough certainty on design endurance lift during preliminary design process. Structural operation conditions, operation load history, property of material and manufacturing process etc. should be considered by performing experiment approach. Using the software program for predicting fatigue life quickly and exactly in preliminary design stage saves plenty of time and cost generated by fatigue tests. In this paper, fatigue life prediction was performed on the basis of fatigue analysis using MSC/FATIGUE and load data from field test and the life of development items was estimated and compared through the results.

• 한국빅데이터학회지
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• 제3권1호
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• pp.47-54
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• 2018

비즈니스 프로세스 분석의 기존 연구들은 비즈니스 프로세스에 포함된 업무, 고객 서비스, 작업자 편의, 수행시간 예측 등 다양한 요소를 분석하였다. 이러한 요소를 정확히 분석하기 위해서는 정보시스템에 기록된 실제 이력 데이터를 활용하는 것이 효과적이다. 프로세스 마이닝은 이벤트 로그 데이터로부터 비즈니스 프로세스의 여러 가지 요소를 분석하는 기법이다. 본 사례 연구는 구매 대행 업체의 업무 수행 데이터에 프로세스 마이닝를 적용하여 구매 대행 프로세스의 업무 흐름, 수행 시간, 담당자 등의 프로세스 운영 분석을 수행하였다.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1449-1458
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• 2006

Controlled Auto-ignition (CAI) combustion processes can be broadly divided between a CAI process that is applied to four-cycle engines and a CAI process that is applied to two-cycle engines. The former process is generally referred to as Homogeneous Charge Compression Ignition (HCCI) combustion and the later process as Active Thermo-Atmosphere Combustion (ATAC) The region of stable engine operation differs greatly between these two processes, and it is thought that the elucidation of their differences and similarities could provide useful information for expanding the operation region of HCCI combustion. In this research, the same two-cycle engine was operated under both the ATAC and HCCI combustion processes to compare their respective combustion characteristics. The results indicated that the ignition timing was less likely to change in the ATAC process in relation to changes in the fuel octane number than it was in the HCCI combustion process.

• 한국경영과학회지
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• 제22권3호
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• pp.99-111
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• 1997

We consider a production system with post-operation and early set-up. As soon as there are no more units(raw materials) to process and the machine becomes idle, it undergoes a post-operation. After the post operation, if the number of waiting units is greater than or equal to m, it begins a set-up. After the set-up, if the number of units is greater than or equal to N($\geq$m), it begins to process the units. We first analyze the system by employing the decomposition property of the vacation queue. We, then, propose an algorithm that finds the optimal threshold values ($m^*$, $N^*$). Finally we present some numerical examples and interprete the system behavior.

• 여성건강간호학회지
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• 제14권2호
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• pp.114-123
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• 2008

Purpose: This study aimed to explore women's actual experiences of Dan Jeon Breathing after a cancer operation with a view to gaining a deeper understanding of their individual experiences and the meaning that it holds for them. Methods: A phenomenological approach was used for this study. Data were collected using in-depth interviews. Study participants were 8 women aged $32{\sim}53$ years who have were practicing Dan Jeon Breathing over the 3 months after cancer operation. The method proposed by Colaizzi (1978) was used to guide the process of data analysis. Results: Themes which emerged from the data were: 'feeling of self-confidence', 'positive acceptance', 'expectation', and 'enervation'. Conclusions: This study provides us with an understanding on the practice and the process of Dan Jeon Breathing for cancer women to overcome cancer Therefore, women who have had an operation for cancer can pursue Dan Jeon Breathing as a nursing intervention.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1022-1027
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• 1997

The grinding operation is an important machining process for machining of final surface. However. grinding process has inevitable troubles such as loading and glazing for grinding wheel. It is, therefore, an essential research theme to determine the wheel life and the dressing timefor efficient grinding. In this study, AE signals (AEavg) generated in thc grinding operation were measured and the dressing time was determined from the analysis of the AEavg value. To verify the propriety of the obtained result. the AE signals measured on the grinding and the dressing operation were compared with the grinding force signals and the dressing force which were measured at same time. From the obtained result, it was confirmed that the determination of the wheel life and the dressing time by the AE measurement technique proposed in this study can be practically used.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.199-204
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• 2000

A low temperature differential model stirling engine is manufactured, and its operation characteristics are measured and analyzed by SIMPLE analysis model, in which heat transfer processes are simply considered. The heat transfer coefficients between working fluid and heat sources in the analysis are estimated by comparing the P-V diagrams by experiment and by analysis. This result may be very useful for further design and manufacture of model Stilting engines as well as real engines because it provides a comparatively correct predictions of the operation conditions and power output. It will be also conveniently used as an educational material for mechanical engineering students because it can be a nice example of optimal design process to decide the phase angle and compression ratio of engine design with a simple but realistic simulation.