• 융복합기술연구소 논문집
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• 제6권1호
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• pp.1-5
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• 2016

Additive manufacturing is converting a digitally designed object into a tangible three dimensional solid using an additive process where materials are applied in successive layers with no or very limited material waste. It can be distinguished form traditional manufacturing which begins with a fixed amount of raw material and removes excess to arrive at the final product. Generally there are five stages to the additive manufacturing supply chain, namely materials, systems, software, application design and production. In this paper, recent market trends and technology about additive manufacturing based on supply chain are analyzed and reviewed.

• 한국정보통신학회논문지
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• 제12권12호
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• pp.2253-2258
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• 2008

산화물 반도체 감지막이 동작온도에 따라 감응특성을 가지는 마이크로 흐름센서를 설계하기 위해서 통계적 수법에 기초한 Markov 체인 MCM을 이용하여 기초방정식을 정식화하고 마이크로 소자의 열 전달특성을 해석하였다. 계산 결과를 통하여 기존 유한차분법이 가지는 계산 정밀도와 차이가 없음을 확인하였다. 본 논문에서 제안한 Markov 체인 MCM을 활용하면 다양한 마이크로 소자의 열전달 특성과 같은 물리적 특성을 해석하고 설계하는데 유용할 것으로 판단된다.

• Computers and Concrete
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• 제7권6호
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• pp.533-547
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• 2010

Recent developments in concrete mixing made possible the production of concretes with high compressive strength showing, simultaneously, high workability. These concretes also present high strengths at young ages, allowing the application of loads sooner. It is of fundamental importance to verify if creep models developed for current concrete still apply to these new concretes. First, a FEM-based software was adopted to test available creep models, most used for normal strength concrete, considering examples with known analytical results. Several limitations were registered, resulting in an incorrect simulation of three-dimensional creep. Afterwards, it was implemented a Kelvin-chain algorithm allowing the use of a chosen number of elements, which adequately simulated the adopted examples. From the comparison between numerical and experimental results, it was concluded that the adopted algorithm can be used to model creep of high strength concrete, if the material properties are previously experimentally assessed.

• Applied Microscopy
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• 제48권4호
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• pp.81-86
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• 2018

The respiratory chain complex forms a supercomplex (SC) in the inner mitochondrial membrane. This complex facilitates the process of electron transfer to produce the proton gradient used to synthesize ATP. Understanding the precise structure of the SC is considered an important challenge. However, it has not yet been reported. The development of a Cryo-electron microscopy (EM) technique provides an effective way to obtain high-resolution micrographs to determine the high-resolution three-dimensional structure of biomolecules. In this brief review, the currently reported Cryo-EM structures of the mammalian respirasome have been described in order to establish a direction for further research in the respiratory system.

• 한국정보통신학회논문지
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• 제27권1호
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• pp.135-138
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• 2023

In this paper, we study real-time error in the context of monitoring a binary information source through a delay system. To derive the average real-time error, we model the delay system as a discrete time Geo/D/1/1 queueing model. Using a discrete time three-dimensional Markov chain with finite state space, we analyze the queueing model. We also perform some numerical analysis on various system parameters: state transition probabilities of binary information source; transmission times; and transmission frequencies. When the state changes of the information source are positively correlated and negatively correlated, we investigate the relationship between transmission time and transmission frequency.

• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.471-477
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• 1998

Taq DNA polymerase from Thermus aquaticus is very useful in the polymerase chain reaction. Taq DNA polymerase is classified in the pol I family, represented by E. coli DNA polymerase I. The three-dimensional structural alignment of 3'-5'exonuclease domains from the pol I family DNA polymerases explains why Taq DNA polymerase does not carry out proofreading in polymerase chain reactions. Three sequence motifs, Exo I, II, and III, must exist to carry out 3'-5'exonuclease activity for proof- reading by a 3'-5'exonuclease reaction, but these are abolished in Taq DNA polymerase. The key catalytic module in 3'-5'exonuclease is two metal ions chelated by four active-site carboxylic amino acids. Taq DNA polymerase was mutagenized to construct the catalytic module in the active site. The circular dichroism technique supported the formation of the catalytic module, and the radioactive assay showed that the 3'-5'exonuclease activity doubled in the mutant Taq DNA polymerase.

• Industrial Engineering and Management Systems
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• 제14권4호
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• pp.347-371
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• 2015

A hybrid procedure based on multi-Criteria Satisfaction Analysis (MUSA) and a Network Data Envelopment Analysis (NDEA) is proposed to evaluate the relative efficiency of customer services in bank branches. First, a three-stage process including sub-processes such as customer expectations, customer satisfaction, and customer loyalty, is defined to model the banking customer services. Then, fulfillment of customer expectations, customer loyalty level, and the customer satisfaction degree are measured and quantified through a multi-dimensional questionnaire based on customers' perceptions analysis and MUSA method, respectively. The customer services scores and the other criteria such as mean of employee evaluation score, operation costs, assets, deposits, loans, number of accounts are considered in network three-stage DEA model. The proposed NDEA model is formed based on multipliers perspective, output-oriented, and constant return to scale assumptions. The proposed NDEA model quantifies and assesses the total efficiency of main process and assigns the efficiency to customer expectations, customer satisfactions, and customer loyalties sub-processes in bank branches. The whole procedure is applied on 30 bank branches in IRAN. The proposed approach can be used in other organizations such as airports, airline agencies, urban transportation systems, railway organizations, chain stores, chain restaurants, public libraries, and entertainment centers.

• Macromolecular Research
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• 제14권5호
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• pp.559-564
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• 2006

The improvement of spatial resolution is a fundamental issue in the two-photon, polymerization-based, laser writing. In this study, a voxel tuning method using a radical quencher was proposed to increase the resolution, and the quenching effect according to the amount of radical quencher was experimentally investigated. Employing the proposed method, the lateral resolution of the line patterns was improved almost to 100 nm. However, a shortcoming of the quenching effect was the low mechanical strength of polymerized structures due to their short chain lengths. Nano-indentation tests were conducted to evaluate quantitatively the relationship between mechanical strength and the mixture ratio of the radical quencher into the resins. The elastic modulus was dramatically reduced from an average value of 3.015 to 2.078 GPa when 5 wt% of radical quencher was mixed into the resin. Three-dimensional woodpile structures were fabricated to compare the strength between the resin containing radical quencher and the original resin.

• 한국물환경학회지
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• 제31권4호
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• pp.367-376
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• 2015

The momentum and kinetic turbulent energy carried by the wind to a stratified lake lead to basin-scale motions, which provide a major driving force for vertical and horizontal mixing. A three-dimensional (3D) hydrodynamic model was applied to Lake Tahoe, located between California and Nevada, USA, to simulate the dominant basin-scale internal waves in the deep lake. The results demonstrated that the model well represents the temporal and vertical variations of water temperature that allows the internal waves to be energized correctly at the basin scale. Both the model and thermistor chain (TC) data identified the presence of Kelvin modes and Poincare mode internal waves. The lake was weakly stratified during the study period, and produced large amplitude (up to 60 m) of internal oscillations after several wind events and partial upwelling near the southwestern lake. The partial upwelling and followed coastal jets could be an important feature of basin-scale internal waves because they can cause re-suspension and horizontal transport of fine particles from nearshore to offshore. The internal wave dynamics can be also associated with the distributions of water quality variables such as dissolved oxygen and nutrients in the lake. Thus, the basin-scale internal waves and horizontal circulation processes need to be accurately modeled for the correct simulation of the dissolved and particulate contaminants, and biogeochemical processes in the lake.

• 한국해안해양공학회지
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• 제14권3호
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• pp.183-191
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• 2002

해수교환이 우수하고, 조차에 따라 상·하로 자유롭게 운동하며, 연약지반과 대수심역에도 설치될 수 있다는 것을 일반적인 부방파제의 주요한 특징으로 들 수 있다. 본 연구는 말뚝계류된 부방파제에 의한 3차원파랑제어와 동적인 거동을 경계적분법과 고유함수전개법을 병용하는 수치해석법으로부터 논의한다. 여기서, 말뚝계류시스템은 연직운동만이 허용되고 다른 운동성분들은 모두 구속되며, 체인계류시스템보다도 파랑에너지의 흡수가 많은 것으로 알려져 있다. 본 연구에서는 말뚝계류에 있어서 말뚝과 본체인 폰툰과의 사이에 작용하는 마찰력과 같은 저항력은 고려되지 않는다. 수치해석결과에 따르면 부방파제의 홀수와 폭의 변화는 파랑제어에 큰 영향을 미치고, 입사파의 주기가 길면 부방파제를 통한 전달파가 크다는 것을 알 수 있다. 그리고, 부방파제의 연직운동은 단주기파에서 크게 나타난다.