• 대한토목학회논문집
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• 제29권6D호
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• pp.675-683
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• 2009

본 논문에서는 도로와 철도에서 자동차와 열차주행시에 발생하는 진동에너지를 건축-토목 구조물에 활용 가능한 전기에너지로 변환하는 진동력 발전시스템 인프라 구축을 위한 기초 개념에 대해 연구하였다. 본 연구에서는 자기유도기술을 활용하여 진동에너지를 전기에너지로 변환하는 진동력 발전장치를 제안하고, 자기유도기술의 기본 원리 및 진동력 발전장치의 동적특성에 대해 설명하였다. 마지막으로 외력과 진동속도에 따라 진동력 발전장치에서 발생하는 기전력의 세기와의 상관관계를 분석하기 위해 다양한 변수를 두고 실내실험을 수행하였고, 이러한 실험결과를 토대로 시험용 진동력 발전장치의 적용성과 효용성을 분석하여, 최대 가용 전력을 획득하기 위한 진동력 발전시스템의 최적설계에 대한 기초 자료를 확보하였다.

• 영어영문학
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• 제58권6호
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• pp.1001-1021
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• 2012

This paper is concerned with John Ashbery's poetics of difficulty, questioning in particular the nature of communication in his difficult poems. Ashbery has an idea of poetry as 'information' to be transmitted to the reader. Meaning, however, is to be created by a series of selections among equally probable choices. Ashbery's poetry has been characterized by resistance to the interpretive system of meaning. But the resistance itself, as I will argue, can be an effective medium of communication as the communicated message is not simply transmitted but 'selected' and thus created by the reader. In Ashbery's poetry, disruptive 'noise' elements can be processed as constructive information. What is normally considered a hindrance or noise can be reversed and added to the information. In Ashbery's poems, random ambiguities or noises can be effectively integrated into the final structure of meaning. Such a stochastic sense of information transfer has been embodied in Ashbery's idea of creating a network of verbal elements in his poetry, analogous to the interconnecting web of hypertext, the most dynamic medium 'information technology' has brought to us. John Ashbery, whose poems are simultaneously incomprehensible and intelligent, employs ambiguities or noise in his poetry, with an attempt to reach through linear language to express nonlinear realities. It is therefore my intention to examine Ashbery's poetics of difficulty, from a perspective of communication transmission, using the theories of information technology and the principles of hypertext theory. Ashbery's poetry raises precisely the problem confronted in the era of communication and information technology. The paper will also show how his aesthetics of difficulty reflects the culture of our uncertain times with overflowing information. With his difficult enigmatic poems, Ashbery was able to move ahead of the technological advances of his time to propose a new way of perceiving the world and life.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.166-166
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• 2022

본 연구의 목적은 고전적 순간단위도 모형 중의 하나인 Nash 모형의 매개변수와 하천망의 동적 Fractal 차원 사이의 관계를 체계적으로 분석하여 해당 매개변수의 수문학적 의미를 추론해 보는 것이다. Nash 모형의 경우, GIUH 이론과의 결합을 통하여 Horton 비를 기반으로 한 두 매개변수의 지형학적 추정 방법이 일찍부터 제안되어 왔다 (Rosso, 1984; Bhunya, 2008). 특히 Liu(1992)는 2차원 자유 Euclidean 공간 내에서 percolation cluster 모형의 응집구조와 유역의 배수구조 사이의 비교를 통하여 하천망의 Fractal 차원을 정적 Fractal 차원과 동적 Fractal 차원으로 구분하고 양자의 수문학적 의미에 대하여 강조한 바 있다. 본 연구에서는 문헌 조사 (Morisawa, 1962; Marani et al., 1991; Rosso et al., 1991)를 통하여 수집한 비교적 신뢰성 있는 국외 하천망들에 관한 정보를 기반으로 Nash 모형의 매개변수와 하천망의 동적 Fractal 차원 사이의 관계를 분석해 보았다. 주요한 결과로서 Nash 모형의 형상 매개변수와 하천망의 Fractal 차원 사이에는 밀접한 상관관계가 존재함을 알 수 있었으며 이를 통하여 하천망의 Fractal 차원을 이용하여 해당 매개변수를 직접 추정할 수 있는 관계식을 제시할 수 있을 것으로 판단된다. 또한 분광 차원과 Nash 모형의 첨두 좌표 사이의 관계를 통하여 겉보기에서로 다른 유역들 사이에 존재할 수 있는 수문학적 상사성을 평가할 수 있는 기준의 수립 역시 본 연구과정을 통하여 제시할 수 있으로 판단된다. 후속 연구로서 국내외 다수 유역들에 대한 지형분석을 통하여 본 연구에서 얻은 결과의 보편성을 검정하고 수문학적 자료들에 대한 검증을 통하여 Nash 모형을 기반으로 한 다양한 수문학적 모형들의 개선 방안을 제시해 보고자 한다.

• Earthquakes and Structures
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• 제23권2호
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• pp.129-138
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• 2022

One of the objectives to prevent building pounding between two adjacentstructures is to considerseparation distance or decrease relative displacement during seismic excitation. Although the majority of building codes around the world have basically suggested some equations or approximately recommended various distances between structuresto avoid pounding hazard, but a lot of reportsin zone of pounding have obviously shown thatsafety situation or economic consideration are not always provided due to the collisions between buildings and the cost of land, respectively. For this purpose, a dynamic MDOF model by having base isolation system is numerically considered and using various earthquake records, relative displacements are mathematically investigated. Different equations to determine the value of damping ratio are collected and the results of evaluations are listed for comparison among them to present a new equation for determination of impact damping ratio. Presented equation is depends significantly on impact velocity before and after impact based on artificial neural network, which the accuracy of them is investigated and also confirmed. In order to select the optimum equation, hysteresisloop of impact between base of building and rubber bumper is considered and compared with the hysteresis loop of each impact, calculated by different equations. Finally, using representative equation, the effect of thickness, number and stiffness of rubber bumpers are numerically investigated. The results of analysis indicate that stiffness and number of bumpers have significantly affected in zone of impact force while the thickness of bumpers have not shown significant influence to calculate impact force during earthquake. For instance, increasing the number of bumpers, gap size between structures and also the value of stiffness is caused to decrease impact force between models. The final evaluation demonstrates that bumpers are able to decrease peak lateral displacement of top story during impact.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.32-41
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• 2017

Accidents on offshore oil and gas platforms (OOGPs) usually cause serious fatalities and financial losses considering demanding environment platforms locate and complex topsides structure platforms own. Evacuation planning on platforms is usually challenging. The computational tool is a good choice to plan evacuation by emergency simulation. However, the complex structure of platforms and varied evacuation behaviors usually weaken the advantages of computational simulation. Therefore, this study developed a simulation model for OOGPs to evaluate different evacuation plans to improve evacuation performance by integrating building information modeling (BIM) and agent-based model (ABM). The developed model consists of four parts: evacuation model input, simulation environment modeling, agent definition, and simulation and comparison. Necessary platform information is extracted from BIM and then used to model simulation environment by integrating matrix model and network model. During agent definition, in addition to basic characteristics, environment sensing and dynamic escape path planning functions are also developed to improve simulation performance. An example OOGP BIM topsides with different emergent scenarios is used to illustrate the developed model. The results showed that the developed model can well simulate evacuation on OOGPs and improve evacuation performance. The developed model was also suggested to be applied to other industries such as the architecture, engineering, and construction industry.

• Korean Journal of Radiology
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• 제24권11호
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• pp.1131-1141
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• 2023

Objective: Cortical iron deposition has recently been shown to occur in Alzheimer's disease (AD). In this study, we aimed to evaluate how cortical gray matter iron, measured using quantitative susceptibility mapping (QSM), differs in the clinical cognitive impairment spectrum. Materials and Methods: This retrospective study evaluated 73 participants (mean age ± standard deviation, 66.7 ± 7.6 years; 52 females and 21 males) with normal cognition (NC), 158 patients with mild cognitive impairment (MCI), and 48 patients with AD dementia. The participants underwent brain magnetic resonance imaging using a three-dimensional multi-dynamic multi-echo sequence on a 3-T scanner. We employed a deep neural network (QSMnet+) and used automatic segmentation software based on FreeSurfer v6.0 to extract anatomical labels and volumes of interest in the cortex. We used analysis of covariance to investigate the differences in susceptibility among the clinical diagnostic groups in each brain region. Multivariable linear regression analysis was performed to study the association between susceptibility values and cognitive scores including the Mini-Mental State Examination (MMSE). Results: Among the three groups, the frontal (P < 0.001), temporal (P = 0.004), parietal (P = 0.001), occipital (P < 0.001), and cingulate cortices (P < 0.001) showed a higher mean susceptibility in patients with MCI and AD than in NC subjects. In the combined MCI and AD group, the mean susceptibility in the cingulate cortex (β = -216.21, P = 0.019) and insular cortex (β = -276.65, P = 0.001) were significant independent predictors of MMSE scores after correcting for age, sex, education, regional volume, and APOE4 carrier status. Conclusion: Iron deposition in the cortex, as measured by QSMnet+, was higher in patients with AD and MCI than in NC participants. Iron deposition in the cingulate and insular cortices may be an early imaging marker of cognitive impairment related neurodegeneration.

• IMMUNE NETWORK
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• 제23권1호
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• pp.3.1-3.14
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• 2023

Microvilli are outer membrane organelles that contain cross-linked filamentous actin. Unlike well-characterized epithelial microvilli, T-cell microvilli are dynamic similar to those of filopodia, which grow and shrink intermittently via the alternate actin-assembly and -disassembly. T-cell microvilli are specialized for sensing Ags on the surface of Ag-presenting cells (APCs). Thus, these finger-shaped microprotrusions contain many signaling-related proteins and can serve as a signaling platforms that induce intracellular signals. However, they are not limited to sensing external information but can provide sites for parts of the cell-body to tear away from the cell. Cells are known to produce many types of extracellular vesicles (EVs), such as exosomes, microvesicles, and membrane particles. T cells also produce EVs, but little is known about under what conditions T cells generate EVs and which types of EVs are released. We discovered that T cells produce few exosomes but release large amounsts of microvilli-derived particles during physical interaction with APCs. Although much is unanswered as to why T cells use the same organelles to sense Ags or to produce EVs, these events can significantly affect T cell fate, including clonal expansion and death. Since TCRs are localized at microvilli tips, this membrane event also raises a new question regarding long-standing paradigm in T cell biology; i.e., surface TCR downmodulation following T cell activation. Since T-cell microvilli particles carry T-cell message to their cognate partner, these particles are termed T-cell immunological synaptosomes (TISs). We discuss the potential physiological role of TISs and their application to immunotherapies.

• 경영정보학연구
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• 제19권1호
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• pp.123-145
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• 2017

한국의 게임시장은 전 세계 시장의 약 29%의 시장점유율을 차지할 정도로 급성장하였다. 특히, 온라인게임의 수출 규모는 24억 USD를 달성할 정도로 국가경제에서 큰 비중을 차지하고 있다. 이렇게 게임 산업이 급성장하면서 게임 산업에 대한 국가적 차원의 정책과 규제에 대해 여러 논의가 이루어지고 있다. 특히, 웹보드 게임에 대해 정부는 여러 주무 부처를 통한 셧다운제, 행정처분, 게임산업진흥법 시행령 등 다양한 규제정책을 시행하고 있는 실정이다. 이러한 배경에서 본 연구는 2012년 11월에 이루어진 웹보드 규제정책의 영향을 분석하기 위해 2010년 12월부터 2014년 11월까지 약 4년여 간의 게임 트릭스 시계열 자료를 단위근 검정, 벡터자기회귀(VAR, Vector Auto-Regression) 분석, 그랜저 인과관계 검정을 수행하였다. 이를 통해 웹보드 규제 정책 시행 전후의 웹보드 게임서비스 간의 충격 파급효과와 예측 이용시간 변화를 알아보았다. 분석 결과를 바탕으로 웹보드 규제 정책이 실질적으로 정부가 의도한 결과대로 나타냈는지 알아보고, 나아가 웹보드 게임 산업을 보다 건강하게 발전시키기 위한 전략을 제시하고자 한다.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.563-572
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• 2024

Image processing and computer vision technologies are becoming increasingly important in a variety of application fields that require techniques and tools for sophisticated image analysis. In particular, image segmentation is a technology that plays an important role in image analysis. In this study, in order to identify recent research trends on image segmentation techniques, we used the Web of Science(WoS) database to analyze the R&D topography based on the network structure of the author's keyword co-occurrence matrix. As a result, from 2015 to 2023, as a result of the analysis of the R&D map of research articles on image segmentation, R&D in this field is largely focused on four areas of research and development: (1) researches on collecting and preprocessing image data to build higher-performance image segmentation models, (2) the researches on image segmentation using statistics-based models or machine learning algorithms, (3) the researches on image segmentation for medical image analysis, and (4) deep learning-based image segmentation-related R&D. The scientometrics-based analysis performed in this study can not only map the trajectory of R&D related to image segmentation, but can also serve as a marker for future exploration in this dynamic field.

• 설비공학논문집
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• 제12권12호
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• pp.1098-1125
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• 2000

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.