• 한국ITS학회 논문지
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• 제7권1호
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• pp.127-136
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• 2008

최근 도로의 유지관리 개념의 중요성이 대두되면서 도로 자체의 유지보수 확장이나 도로선형 개량 등 도로상에서 각종 공사의 빈도가 증가하고 있다. 특히 고속으로 주행하는 고속도로 상에서 도로점용공사로 인하여 차로가 감소되는 구간은 교통효율과 사고 위험도 측면에서 체계적이고 합리적인 도로점용공사가 필요하지만, 국내의 도로 특성을 반영한 공사구간 도로상에서의 교통사고 측면의 연구가 부족하여 외국의 사례를 적용하고 있는데, 외국은 국가의 면적, 도로의 사정, 국민들의 의식수준 등 여러 가지 상황이 우리나라와 상이하여 외국의 사례를 그대로 적용했을 때에는 실제적으로 우리나라 도로현황과 일치하지 않는 경우가 대부분이다. 이에 고속도로 23개 노선을 중심으로 2003년부터 2005년까지 3년동안 교통통제가 이루어진 공사구간에서 발생한 교통사고를 조사하고 이 공사구간에서 발생하는 교통사고의 특성을 사고유형별, 사고심각도별, 공사유형별, 원인별, 사고 발생경향별, 그리고 전체 고속도로상의 교통사고와의 비교를 통해서 알아보고자 한다. 또한 이를 통해서 보다 구체적이고 세부적인 공사구간 통제지침의 필요성을 제시하고자 한다.

• ETRI Journal
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• 제30권3호
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• pp.441-450
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• 2008

The scalable extension of H.264, known as scalable video coding (SVC) has been the main focus of the Joint Video Team's work and was finalized at the end of 2007. Synchronization between media is an important aspect in the design of a scalable video streaming system. This paper proposes an efficient media synchronization mechanism for SVC video transport over IP networks. To support synchronization between video and audio bitstreams transported over IP networks, a real-time transport protocol/RTP control protocol (RTP/RTCP) suite is usually employed. To provide an efficient mechanism for media synchronization between SVC video and audio, we suggest an efficient RTP packetization mode for inter-layer synchronization within SVC video and propose a computationally efficient RTCP packet processing method for inter-media synchronization. By adopting the computationally simple RTCP packet processing, we do not need to process every RTCP sender report packet for inter-media synchronization. We demonstrate the effectiveness of the proposed mechanism by comparing its performance with that of the conventional method.

• Journal of Mechanical Science and Technology
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• 제16권9호
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• pp.1175-1182
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• 2002

The commercial viability of heat exchanger is mainly dependent on its long-term fouling characteristic because the fouling increases the pressure loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristics of fluid flow and heat transfer in a fluidized bed heat exchanger with circulating various solid particles. The present work showed that the higher densities of particles had higher drag force coefficients, and the increases in heat transfer were in the order of sand, copper, steel, aluminum, and glass below Reynolds number of 5,000.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1752-1754
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• 1998

Recently the research about electron transport characteristic and energy distribute function in mixture gases within Helium, has been used and developed widely as industrial quality improvement of extinguish characteristic, electrical dielectric strength ability of application of each species high voltage apparatus, gas plasma etching progress of work to use manufacture of semiconductor, thin film molding by CVD, insulation film to use ultra LSI, etc. This paper analyze electron transport characteristic in the range E/N $1{\sim}60$[Td], pressure $0.1{\sim}6.0$[Torr] by MCS. It is necessary to seek electron drift velocity, diffusion coefficient, lonization coefficients, characteristic energy, mean energy and electron energy distribution function as electron transport characteristic.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.365-370
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• 2000

Sea dike construction for the tidal flat reclamation works in estuary and coast may change the characteristics of tidal motion and wave conditions in the region. In turn, a new hydraulic condition provides the impacts on sediment transport pattern and forms a new morphological environment. Also, morphological changes during the closure works of sea dike are closely related with a safy of sea dike. Therefore, the prediction of morphological changes is required secure the safe closure work and the economic design of sea dikes. To investigate morphological changes due to sea dike construction, hydrodynamic changes of tides and waves have to be evaluated, then sediment transport and sea bottom changes are computed. Mathematical modelling is required for representation of interrelation of tidal motion, wave and sediment transport. In this study, numerical model MORSYS is applied to compute the hydrodynamics and morphological changes around the closure gap for Saemankuem dike. This model allows a flexible integration of the module for waves, currents, sediment transport and bottom changes.

• 설비공학논문집
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• 제16권8호
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• pp.691-697
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• 2004

Experimental study is carried out to investigate the heat transport capability and thermal resistance of sinusoidal axially grooved heat pipe, comparing its performance to trapezoidal axially grooved heat pipe. As a result from this work, the heat transport capability of sinusoidal grooved heat pipe is lower than that of trapezoidal grooved heat pipe for the same size of outer diameter. As the ratio of depth to width of sinusoidal groove heat pipe is higher, the heat transport capability of heat pipe becomes higher. It is found that Aluminum-ammonia heat pipes with sinusoidal and trapezoidal grooves have good thermal resistance, below 0.1$^{\circ}C$/W at evaporator section and below 0.05$^{\circ}C$/W at condenser section.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1189-1198
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• 2017

Computer-aided design (CAD)-based Monte Carlo radiation transport is of value to the nuclear engineering community for its ability to conduct transport on high-fidelity models of nuclear systems, but it is more computationally expensive than native geometry representations. This work describes the adaptation of a rendering data structure, the signed distance field, as a geometric query tool for accelerating CAD-based transport in the direct-accelerated geometry Monte Carlo toolkit. Demonstrations of its effectiveness are shown for several problems. The beginnings of a predictive model for the data structure's utilization based on various problem parameters is also introduced.

• Coupled systems mechanics
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• 제6권1호
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• pp.75-96
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• 2017

As electron donor/acceptor materials for organic photovoltaic cells, small-molecules donors/acceptor are attracting more and more attention. In this work, we investigated the electronic structures, electrochemical properties, and charge carrier transport properties of four recently-synthesized small-molecule donors/acceptor, namely, DPDCPB (A), DPDCTB (B), DTDCPB (A1), and DTDCTB (B1), by a series of ab initio calculations. The calculations look into the electronic structure of singly oxidized and reduced molecules, the first anodic and cathodic potentials, and the electrochemical gaps. Results of our calculations were in accord with those from experiments. Using Marcus theory, we also computed the reorganization energies of hole/electron hoppings, as well as hole/electron transfer integrals of multiple possible molecular dimer configurations. Our calculations indicated that the electron/hole transport properties are very sensitive to the relative separations/orientations between neighboring molecules. Due to high reorganization energies for electron hopping, the hole mobilities in the molecular crystals are at least an order of magnitude higher than the electron mobilities.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.109-116
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• 2022

The article is devoted to perfecting the system of management of the financial potential of transport enterprises. It is established that transport as an integral part of the state economy has to organically enter the market economy and provide sustainable transport services to national economy enterprises regardless of ownership, as well as ensure passenger transportation. It is also determined that in the conditions of market relations, transport highways must perform their functions with sufficient economic benefit to keep their material and technical resources in good order, conduct an investment policy with extensive use of scientific and technological progress, as well as a social policy guaranteeing the conditions for employees' motivated work. The study reveals an association between the financial and strategic goals of transport enterprises and the minimization of their economic risks, the prevention of bankruptcy and profit margin shortfalls. It is found that transport enterprises need to strive for the overall improvement of their financial potential through increasing the components of financial potential and assessing the impact of risk factors on them: the capacity of fixed assets, the capacity of financial resources, the capacity of services, and the capacity of credit opportunities. These are the elements of transport enterprises' financial potential that ensure its desired level. It is demonstrated that of critical importance in managing the financial potential of a transport enterprise is the role of financial resources, as a subject cannot reach the desired strategic goals without them.

• 한국세라믹학회지
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• 제47권1호
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• pp.86-91
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• 2010

Among various fuel cells, solid oxide fuel cells (SOFCs) offer the highest energy efficiency, when taking into account the thermal recycling of waste heat at high temperature. However, the highest efficiency and lowest pollution for a SOFC can be achieved through the sophisticated control of its constituent components such as electrodes, electrolytes, interconnects and sealing materials. The electrochemical conversion efficiency of a SOFC is particularly dependent upon the performance of its electrode materials. The electrode materials should meet highly stringent requirements to optimize cell performance. In particular, both mass and charge transport should easily occur simultaneously through the electrode structure. Matter transport or charge transport is critically related to the configuration and spatial disposition of the three constituent phases of a composite electrode, which are the ionic conducting phase, electronic conducting phase, and the pores. The current work places special emphasis on the quantification of this complex microstructure of composite electrodes. Digitized images are exploited in order to obtain the quantitative microstructural information, i.e., the size distributions and interconnectivities of each constituent component. This work reports regarding zirconia-based composite electrodes.