• 한국자동차공학회논문집
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• 제8권5호
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• pp.20-27
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• 2000

Characteristics of two favorite injection tools for gasoline direct injection application were compared. An air-assisted fuel injector (AAFI) and a high-pressure swirl injector (HPSI) were designed and fabricated for prototype development, and the characterization strategies and processes for both injection tool have been arranged in parallel. Characterization works were carried out mainly through measurements, and in some cases, computational fluid dynamic analysis was utilized. In this paper, overall characteristics defined as flow rate, spray pattern, penetration, internal spray structure and drop size distribution, was discussed. The AAFI was found to be advantageous in flexibility of fuel flow rate, and the HPSI in stability and precision. Spray shape factor was introduced to describe the development of intermittent sprays from both injectors. Axial penetration appeared to be almost linear in the case of the AAFI while its speed continuously decreased with time in the HPSI.

• 한국해양공학회지
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• 제31권1호
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• pp.47-59
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• 2017

This study conducted numerical simulations using LES-WASS-3D ver. 2.0 to analyze the seawater intrusion characteristics of the incident waves in a coastal aquifer. LES-WASS-3D directly analyzed the nonlinear interaction between the seawater and freshwater in a coastal aquifer, as well as the wave-current interaction in the coastal area. First, the LES-WASS-3D results were compared with the existing experimental results for the mean water level under wave action in the coastal aquifer and seawater penetration into the coastal aquifer. The mean water level, shape and position of the seawater-freshwater interface, and intrusion distance were well implemented in the results. This confirmed the validity and effectiveness of LES-WASS-3D. The overall seawater penetration distance increases in the coastal aquifer as a result of wave set-up and run-up in the swash zone caused by continuous wave actions, and it increases with the wave height and period. Furthermore, a numerical verification was performed by comparing the suggested existing structure and newly suggested curtain wall as a measure against seawater penetration. An existing underground dam showed a better effect with increased height. Additionally, the suggested curtain wall had a better effect when the embedded depth was increased.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.40-47
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• 2010

This study deals with the investigation about the effect of the pilot and split injection strategies on the spray-atomization characteristics of biodiesel fuel derived from a soybean oil. Experimental results were compared with the calculation results obtained from the numerical analysis. Fuel properties of biodiesel according to the variation of the fuel temperature were inserted to the fuel library in the KIVA code. The amount of fuel injection is divided into equal mass for each split and main injection. In this work, the pilot injection strategy can be achieved by the amount of fuel injection shortly before the start of the main injection. A spray tip penetration, radial distance and spray area were measured for the analysis of macroscopic spray characteristics. In addition, the local and overall droplet size distribution were calculated by using KIVA-3V code to study the effect of split and pilot injection on the atomization performance under high ambient pressure. From these studies, the experimental results showed the multiple injection induced the decrease of the spray tip penetration due to the reduction and division of the spray momentum compared to single injection. In the atomization performance, the droplet size increased in the case of the multiple injection a little. Moreover, the SMD slightly increased as the fuel droplets goes through the axial direction. The spray behavior of numerical results were well predicted the experimental multiple spray characteristics of biodiesel fuel.

• 한국콘텐츠학회논문지
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• 제15권9호
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• pp.509-526
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• 2015

본 연구에서는 N-스크린 시대의 미국, 영국, 일본의 유력 신문사의 디지털 콘텐츠 유료화 전략을 비교, 분석했다. 분석의 틀로는 디지털 콘텐츠의 유료화 시점, 시장 세분화 여부, 4P 마케팅 믹스 전략이 활용됐다. 해외 주요 신문사들의 디지털 콘텐츠 유료화 전략은 2000년을 전후로 시작된 후, 2000년 초중반 캐즘을 겪었고 2010년 모바일 기기의 확산으로 본격화된 것으로 나타났다. 분석 대상 신문사 대부분은 상품 측면에서 시장을 세분화하는 모습을 보이진 않았다. 4P 전략의 관점에서 상품 전략의 경우, e-paper와 디지털 콘텐츠를 축으로 프리미엄 서비스가 부가되는 방식으로 전개되고 있었다. 가격 전략은 연성 체계와 혼합 체계가 주로 활용됐다. 유통전략은 디지털 콘텐츠에 대한 세분화 여부에 따라 대별됐다. 디지털 콘텐츠의 유통경로는 '디지털'로 묶어 하나의 대상으로 간주하면 단일 요금제, 그렇지 않고 각각의 단말기마다 세분화 한 경우에는 복합 요금제가 선택됐다. 판촉 전략에서는 종이신문과의 번들링 전략이 주로 채택되는 가운데, 시범 이용을 두고 분석 결과가 서구(미국과 영국)와 일본 간 상이하게 나타났다.

• 통상정보연구
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• 제15권2호
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• pp.49-69
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• 2013

아프리카는 석유가스를 비롯한 각종 광물자원의 보고로서 자원의 확보는 물론 향후 신흥시장 선점, 외교적 영향력 확대라는 측면에서 다방면에서의 진출이 필요하다. 아프리카의 전략적 가치를 고려할 때 아프리카 시장은 무한한 잠재력을 가진 지역이며, 자원이 빈곤한 우리나라로서는 적절한 시장진입 전략 선택과 성과에 대한 올바른 평가가 매우 중요하다. 이에 본 논문은 한국기업의 수출환경특성-아프리카 진출전략-기업성과 간의 인과관계분석을 통해 아프리카 진출 성과를 분석하고자 하였다. 분석 결과, 해외시장진입 전략 요인 중 해외시장진입시기, 기업의 경쟁전략, 마케팅 전략은 기업성과에 유의한 정(+)의 영향을 미치는 것으로 나타났다. 따라서 아프리카 시장에서 기업이 성과를 향상시키기 위해서는 아프리카 시장 특성에 맞는 집중화 및 세분화 전략, 마케팅 전략이 필요하다.

• 미생물학회지
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• 제55권2호
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• pp.87-102
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• 2019

대부분의 만성창상(chronic wounds)은 생물막으로 인해 상처 치유시 염증단계를 지속시킨다. 생물막은 항생제(antibiotics)에 대한 저항성을 가지며 침투력을 저하시키고 살균제(biocides)에 대한 내성을 지니며 국소면역반응을 약화시킨다. 또한 생물막은 주변의 조직에 단단히 붙어 있어 제거하는 작업이 매우 어렵다. 그러므로 주변 조직을 손상시키지 않으면서 단단한 생물막을 제거하는 전략은 매우 중요하다. 그 중에 하나가 분산기작을 이용한 생물막의 해체이며 지금까지 많은 연구가 수행되어 왔다. 본 고찰논문에서는 특별히 화학주성, 파지요법, 다당류, 다양한 효소(당분해효소, 단백질분해효소, DNA 분해효소), 계면활성제, 분산신호, 자기유도인자, 조절인자, 억제제 등이 소개되었으며 더 나아가 항생제 치료 및 다른 치료와의 병행을 통한 병합요법도 소개되었다. 앞으로 본 논문에서 제시된 생물막의 분산기작의 지식을 이용하여 만성 창상 감염치료의 가능성이 더 높아지길 기대한다.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.183-192
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• 2014

In this work, the mixture formation and atomization characteristics of biodiesel fuel were reviewed under various test conditions for the optimization of compression-ignition engine fueled with biodiesel. To achieve these, the effect of nozzle caviting flow, group-hole nozzle geometry and injection strategies on the injection rate, spray evolution and atomization characteristics of biodiesel were studied by using spray characteristics measuring system. At the same time, the fuel heating system was installed to obtain the effect of fuel temperature on the biodiesel fuel atomization. It was revealed that cavitation in the nozzle orifice promoted the atomization performance of biodiesel. The group-hole nozzle geometry and split injection strategies couldn't improve it, however, the different orifice angles which were diverged and converged angle of a group-hole nozzle enhanced the biodiesel atomization. It was also observed that the increase of fuel temperature induced the quick evaporation of biodiesel fuel droplet.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1655-1661
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• 2007

최근 유비쿼터스 기술을 응용하여 다양한 산업이 등장하고 있다. 특히 미래 산업으로 관심을 끌고 있는 인류의 건강 관련은 유비쿼터스 시스템과 융합되면서 중요한 산업으로 등장하고 있다. 이를 u-Health산업이라 한다. 국내에서는 지방자치제도에 따라 지역 여건에 맞는 고부가가치 산업을 창출하고자 노력한다. 본 연구는 충북 지역의 특화 산업으로서 u-Health 산업 분야를 가정하고, 제품의 효율적 시장 진입을 위한 마케팅 전략을 연구하였다. 마케팅전략으로는 세계 시장을 대상으로 한 STP 전략를 제시하였다. 전략 구상의 기준은 세계 주요 선진국의 노령화 지수 및 모딜리아니의 생애주기가설을 토대로 연구하였다. 마지막으로 충북 지역에 u-Health 제품 출시가 되지 않은 것을 감안하여 제품 출시 후 활용할 마케팅 믹스 전략 방안을 제시하였다.

• 기록학연구
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• 제10호
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• pp.27-62
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• 2004

As the penetration of information technology into everyday life is accelerated day by day, virtually all kinds of human representation of knowledge and arts are produced and distributed in the digital form. It is problematic, however, because digital objects are so volatile that it is not easy to keep them in fixed form. The fatal fragility makes it extremely tricky to preserve the digital heritage of our time for the next generation. The present paper aims to introduce current endeavors made at the international and the national levels and to provide with suggestions for Korean national strategy of digital preservation. It starts with reviewing the global trends of digital archiving and long-term preservation, focusing on standardization, preservation strategies and current experiments and projects being conducted for preserving various digital objects. It then sketches national strategies of several leading countries. Based on the sketch, twofold suggestions for Korean national strategy are proposed: establishing a central coordinating agency and accommodating the digital preservation issue in the legislative and regulatory framework for the information society. The paper concludes with the necessity of cooperation among heritage organizations, including libraries, archives, museums. They should cooperate with each other because they have traditionally been trusted with the custodianship of collective memory of humankind and the digital heritage cannot be passed onto the next generation without their endeavor. They should also work together because any single institution, or any single nation could cover what it takes to complete the task of long-term preservation of our digital heritage.

• Current Photovoltaic Research
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• 제10권2호
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• pp.49-55
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• 2022

With rapid growth in light-harvesting efficiency from 3.8 to 25.8%, organic-inorganic hybrid perovskite solar cells (PSCs) have attracted great attention as promising photovoltaic devices. However, despite of their outstanding performance, the commercialization of PSCs has been suffered from severe stability issues, especially for UV and humidity: (i) UV irradiation towards PSCs is able to lead UV-induced decomposition of perovskite films or catalytic reactions of charge-transporting layers, and (ii) exposure to surrounding humidity causes irreversible hydration of perovskite layers by the penetration of water molecules, resulting considerable decrease in their power-conversion efficiency (PCE). This review investigates current status of strategies to enhance UV and humidity stability of PSCs in terms of UV-management and moisture protection, respectively. Furthermore, the multifunctional approach to increase long-term stability as well as performance is discussed as advanced research directions for the commercialization of PSCs.