• 한국물환경학회지
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• 제34권4호
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• pp.391-398
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• 2018

The main purpose of this study is to suggest and recommend the more reliable flow direction methods within the framework of DEM and power law distribution, by investigating the existing methodologies. To this end SFD (single flow direction method), MFD (multiple flow direction method) and IFD (Infinite flow direction method) are applied to analyze the determination of a flow direction for the water particles as seen in the Jeonjeokbigyo basin, and then assessed with respect to the variation of flow accumulation in that region. As the main results revealed, the study showed the different patterns of flow accumulation are found out from each applications of flow direction methods utilized in this study. This brings us to understand that as the flow dispersion on DEM increases, in this case the contributing areas to the outlet grow in sequence of SFD, IFD, MFD, but it is noted that the contribution of individual pixels into outlet decreases at that time. In what follows, especially with the MFD and IFD, the result tends to make additional hydrologic abstraction from rainfall excess, as noted due to the flow dispersion within flow paths on DEM. Based on the parameter estimation for a power law distribution, which is frequently used for identify the aggregation structure of complex system, by maximum likelihood flow accumulation can be thought of as a scale invariance factor. In this regard, the combination of flow direction methods could give rise to the more realistic water flow on DEM, as revealed through the separate flow direction methods as utilized for dispersion and aggregation effects of water flow within the available different topographies.

• 대한건축학회논문집:구조계
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• 제35권6호
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• pp.139-146
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• 2019

The modular building system is a type of prefabricated construction method, and is an industrialized building system that transports, assembles, and completes a three-dimensional module manufactured in a factory to the site. The economics of a modular building system where 50 to 80% of the entire process takes place in a modular factory is dominated by productivity of the factory manufacturing process. Since the building of the module is finished by the combination of unit parts produced by each material, it is necessary to manage the process in each module unit. However, currently marketed process control programs do not reflect the features of these modular methods. In this paper, we introduce Modular Factory Design software(MFD 2019) that can make modular unit production plan which reflects production base(modular factory) and production target(application and number of modular units). In order to verify software compatibility and reliability, two production plans with different production methods were formulated and simulated.

• 대한안전경영과학회지
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• 제8권2호
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• pp.71-80
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• 2006

There are many display panels in the flight cockpit and pilots get various flight information from those displays. The ergonomic layout of the displays must be determined based upon frequency of use and sequence of use. This study investigated the visual search patterns of the six display groups(one head-up-display: HUD, two multi function displays: MFDs, one engine group: EG, one flight display group: FD and others) in a fighting aircraft. Four expert pilots conducted Imaginary flight in the physical mock-up and the eye movements were collected using eye tracking system. Data of dwell time, frequency of use, and eye movement path were collected. Pilots spent most of time on HUD(55.2%), and others (21.6%), FD(14.2%), right MFD(4.7%), EG(3.2%), and left MFD(1.1%) in descending order. Similarly HUD(42.8%) and others(30.0%) were the most frequently visited displays. These data can be used in the layout of cockpit displays and the determination of optimal visual search pattern.

• 항공우주시스템공학회지
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• 제15권2호
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• pp.45-51
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• 2021

In this study, we aim to eliminate the flickering phenomenon in multi-function display (MFD) units during the flight of fixed-wing aircraft. To execute flight missions effectively, the video signals transmitted to MFDs must provide information accurately and seamlessly. Therefore, a method for addressing the flickering phenomenon-including cause analysis and failure diagnosis-is adopted; specifically, a wiring configuration with a direct connection between the video signal cables and with a short cable length is adopted. The proposed method is experimentally verified using a flight test.

• Animal Bioscience
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• 제34권11호
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• pp.1849-1858
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• 2021

Objective: Tenderness is a very complex feature, and the process of its formation is very complicated and not fully understood. Its diversification is one of the most important problems of beef production, as a result beef aging is widely used to improve tenderness as it is believed to provide a homogeneous product to consumers. While few studies have evaluated the muscle structure properties in relation to tenderness from early post-mortem, there little to no information available on how the muscle nanostructure of beef carcasses changes during post-mortem ageing to determine the appropriate aging time for acceptable tenderness. Methods: Muscle nanostructure (myofibril diameter [MYD], myofibril spacing [MYS], muscle fibre diameter [MFD], muscle fibre spacing [MFS], and sarcomere length [SL]), meat tenderness and cooking loss [CL]) were measured on 20 A2 longissimus muscles of Bonsmara, Beefmaster, Hereford, and Simbra at 45_mins, 1, 3, and 7 days post-slaughter. Muscle nanostructure was measured using a scanning electron microscope, while tenderness was measured using Warner Bratzler shear force. Results: At 45 minutes post-slaughter, breed affected MYD and MYS only, while at 24_hrs it also affected MFD and MFS. On day 3 breed effected MFS and SL, while on day 7 breed effected tenderness only. As the muscles matured, both MYD and MYS decreased while CL increased, and the muscles became tender. There was no uniformity on muscle texture features (surface structure, fibre separation, muscle contraction, and relaxation) throughout the ageing period. Conclusion: Meat tenderness can be directly linked to breed related myofibril structure changes during aging in particular the MYD, spacing between myofibrils and their interaction; while the MFD, spacing between muscle fibres, SL, and CL explain the non-uniformity in beef tenderness.

• 한국산림과학회지
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• 제112권4호
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• pp.426-441
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• 2023

본 연구에서는 수확벌채에 따른 수목의 뿌리 점착력의 변화와 토양의 포화를 가정한 지표유출의 세 가지 흐름 기법(SFD; Single flow direction, MFD; Multiple flow direction, IFD; Infinite flow direction)을 무한사면 안전율 공식에 적용하여 산사태 발생 예측 모델링의 정확성을 분석하였다. 이를 위해 2020년 8월 집중호우의 영향으로 자연사면과 벌채사면에서 다수의 산사태가 발생한 제천지역을 연구지역으로 선정하였다. 위성영상과 25cm급 항공사진을 이용한 산사태 인벤토리 맵핑 결과, 연구지역 내에서 총 830개소의 산사태 발생원이 확인되었다. 산사태 모델링 결과, 벌채에 따른 뿌리 점착력의 변화를 고려한 경우(MFD: 0.81, IFD: 0.80, SFD: 0.80)가 벌채의 영향을 고려하지 않은 경우(MFD: 0.79, IFD: 0.79, SFD: 0.78)에 비하여 AUROC(Area Under the Receiver Operating Characteristics) 분석에서 정확성이 1.3~2.6% 향상되는 것으로 나타났다. 또한, MFD 알고리즘을 이용한 경우는 다른 알고리즘과 비교하여 AUROC 분석에서 정확성이 최대 1.3% 향상되었다. 이러한 결과는 식생조건의 변화를 고려한 뿌리 점착력의 차등 적용과 지표유출수 흐름기법의 선정이 산사태 예측 모델링에 영향을 미칠 수 있음을 시사한다. 향후 이 연구의 결과는 현지 수문모니터링과 함께 수종별 뿌리 점착력의 특징 및 변화를 고려하여 검증되어야 할 것이다.

• 해양환경안전학회지
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• 제29권2호
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• pp.160-167
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• 2023

통합항해시스템(INS)은 기존 항해 장비들을 통합하여 부가가치를 제공하는 장치로써 항해 업무 수행을 위한 정보와 기능을 다기능표시장치에(MFD)에 통합하는 것으로 정의된다. IMO 성능 기준은 각 업무에 대한 최소 요구사항을 명시하고 있지만, 장비 및 기능의 목록은 정의하지 않아 제조사마다 INS의 구성이 상이하고 사용자 관점에 기반 한 지침 또한 부족한 실정이다. 본 연구는 선박 운용상황 및 수행 업무에 따라 사용자가 요구하는 정보를 분석하고, 이를 INS의 MFD에 효과적으로 구조화하여 INS의 사용성을 높이기 위해 수행되었다. INS 관련 국제 기준 및 제조사의 구성 장비 목록을 분석하여 필수 항해 정보들을 선별하고 MFD 사용 경험이 있는 선박 운항자를 대상으로 카드 소팅 테스트를 실시하여 각 INS 업무에 요구되는 정보들을 분류하도록 하였다. 연구의 결과는 제조사들이 제품 설계 시 사용자 경험을 반영한 정보 구성에 기본적인 가이드로 활용될 수 있을 것이다.

• 한국항행학회논문지
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• 제25권6호
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• pp.433-440
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• 2021

어선의 경계소홀에 의한 해난사고는 어선 운용자의 고령화에 따른 문제와 어선에서 협소한 조타실 내부에 설치되는 항해, 통신 및 어로장비 등 여러 개의 단말기와 모니터는 조타실의 해상시야를 방해하는 상태로 설치된다. 또한 복수의 장비에 표시되는 각각의 디스플레이 정보를 확인해야 하는 혼란으로 운용자의 정보인식 능력을 저하시키는 요인으로 작용한다. 따라서 장비들을 간결하게 통합해야 한다는 요구가 제기되어 왔으며, 통합시스템은 전자해도, 통신 및 어군탐지 등으로 다양하게 어선에서 구비해야 하는 장비와 모니터를 하나로 통합하는 것이다. 본 연구는 어선의 협소한 조타실에 설치되는 GPS 플로터, AIS, VHF- DSC, V-pass, 어군탐지기를 하나의 함체에 구성하고, 하나의 MFD (multi function display)에 의하여 운용을 간편화하는 과제이며, 항해중에 데이터통신을 자동운용하는 AIS 와 V-pass 모듈은 실증실험을 통하여 그 성능을 확인하였다. 어선에서 여러 개의 단말기를 통합하여 하나의 화면으로 모든 정보를 제공하고 운용하는 시스템은 해상안전과 어업환경을 크게 개선시킬 수 있다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.237-251
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• 2002

The recent progress on metabolic systems engineering was reviewed based on our recent research results in terms of (1) metabolic signal flow diagram approach, (2) metabolic flux analysis (MFA) in particular with intracellular isotopomer distribution using NMR and/or GC-MS, (3) synthesis and optimization of metabolic flux distribution (MFD), (4) modification of MFD by gene manipulation and by controlling culture environment, (5) metabolic control analysis (MCA), (6) design of metabolic regulation structure, and (7) identification of unknown pathways with isotope tracing by NMR. The main characteristics of metabolic engineering is to treat metabolism as a network or entirety instead of individual reactions. The applications were made for poly-3-hydroxybutyrate (PHB) production using Ralstonia eutropha and recombinant Escherichia coli, lactate production by recombinant Saccharomyces cerevisiae, pyruvate production by vitamin auxotrophic yeast Toluropsis glabrata, lysine production using Corynebacterium glutamicum, and energetic analysis of photosynthesic microorganisms such as Cyanobateria. The characteristics of each approach were reviewed with their applications. The approach based on isotope labeling experiments gives reliable and quantitative results for metabolic flux analysis. It should be recognized that the next stage should be toward the investigation of metabolic flux analysis with gene and protein expressions to uncover the metabolic regulation in relation to genetic modification and/ or the change in the culture condition.

• 한국기계가공학회지
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• 제8권2호
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• pp.46-52
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• 2009

Drilling operation is such an important machining process, which has been wildly applied to the industry, occupied over 30% of whole industry. However, there are many aspects of drilling process should be improved, such as increases of thrust force, surface roughness, and roundness, ect. In this study, we are aiming to reduce the thrust force, surface roughness, and roundness in drilling process. For this purpose, multi facet drills (MFD) of three types that are modified from standard drill (STD) are developed. The first type is multi stair drill (MSD) with shape of stair on relief plane. The second type is rough facet drill (RFD) with shape of round on relief plane. The third type is rough flute drill (RFLD) with shape of round on flute plane. For three types of MFD, we were carried out performance evaluation from the perspective of thrust force, surface roughness and roundness of machined hole. From obtained result, we could confirmed that performance of rough flute drill (RFLD) type is most excellent.