• 정보학연구
• /
• 제8권4호
• /
• pp.119-140
• /
• 2005

The purpose of this article is to study on the electronic bill of lading in the electronic trade era. The term 'electronic trade' means all or part of any such trade as implemented by means of apparatus having the information processing capability, such as a computer, and networks of information and communications. The introduction of an electronic bill of lading has long been considered essential by the members of the international trading community as a key means of reducing its costly reliance on paper.

• Animal Bioscience
• /
• 제36권12호
• /
• pp.1889-1897
• /
• 2023

Objective: 'Cultured meat' has been suggested as means of solving the problems associated with overpopulation and gas emissions. Satellite cells are a major component in the production of cultured meat; however, these cells cannot be maintained in vitro over long periods. Fibronectin is a glycoprotein that affects biological processes such as cell adhesion, differentiation, and migration. Unfortunately, the characteristics of porcine satellite cells grown in a long-term culture when exposed to fibronectin-coated dishes are unknown. The objective of this study was to investigate the appropriate concentration of fibronectin coated dishes for proliferation and maintenance of porcine satellite cells at long-term culture. Methods: In this study, we isolated the satellite cells and fibroblast cells with pre-plating method. We next analyzed the cell doubling time, cell cycle, and rate of expressed paired box 7 (Pax7) and myogenic differentiation 1 (MyoD1) in porcine satellite cells cultured with 20 ㎍/mL of fibronectin-, gelatin-, and non-coated dishes at early and late passage. We then analyzed the proliferation of porcine satellite cells with various concentrations of mixed gelatin/fibronectin. We next determined the optimal concentration of fibronectin that would encourage proliferation and maintenance of porcine satellite cells in a long-term culture. Results: Doubling time was lowest when 20 ㎍/mL of fibronectin was used (as tested during an early and late passage). Levels of expressed Pax7 and MyoD1, assessed using immunocytochemistry, were highest in cells grown using fibronectin-coated dishes. The proliferation of gelatin/fibronectin mixed coatings had no significant effect on porcine satellite cells. The concentration of 5 ㎍/mL fibronectin coated dishes showed the lowest doubling time and maintained expression of Pax7. Conclusion: Fibronectin with 5㎍/mL effectively maintains porcine satellite cells, a discovery that will be of interest to those developing the next generation of artificial meats.

• 기술사
• /
• 제45권4호
• /
• pp.30-34
• /
• 2012

Shale gas is one of the resources which require lots of new technologies for commercial production and has the most reserves among unconventional gas resources for commercial production at present. Especially, the growth of shale gas industry means the significant changes of paradigm and the development of shale gas is very different from conventional gas development in terms of geology, rock mechanics, petroleum engineering, development and production engineering. In this manner, shale gas may hold the key to expanding the long-term role of gas in the global energy mix.

• 천문학회지
• /
• 제1권1호
• /
• pp.1-18
• /
• 1968

The photometric orbital elements of an Algol-type eclipsing variable, DI Pegasi, are derived by means of Fourier transforms from two-color photoelectric observations. The system shows a long term variation of its orbital period, which is interpreted as due to a continuing mass loss mechanism from the secondary component. Physical dimensions and a model of the system are also suggested here.

• 콘크리트학회논문집
• /
• 제19권1호
• /
• pp.47-56
• /
• 2007

최근들어 고속도로, 고속철도, 지하철등의 건설이 증가하면서 터널의 건설도 늘어나고 있는 추세이다. 이러한 터널 공사에서 필수적으로 따르는 것이 숏크리트 공정이며 이러한 숏크리트의 시공은 앞으로도 더욱 증가할 추세에 있다. 그러나 숏크리트의 광범위한 시공에도 불구하고 여러 가지 문제점을 내포하고 있는 것이 사실이다. 따라서 본 연구에서는 우리나라 현행 숏크리트의 현황과 문제점을 분석하고, 고품질의 숏크리트 시공을 위하여 실리카퓸 숏크리트의 성능 및 적용성에 대해 분석하였다. 또한 숏크리트의 장기적인 안정성 확보를 위해서는 복합적인 환경조건을 고려한 열화 특성을 파악할 필요가 있다. 본 연구에서는 건습 반복, 동결융해 및 탄산화 등의 열화 인자를 복합적으로 적용한 열화 시험을 수행하였다. 특히, 우수한 강도 증진 효과로 국외에서 많이 사용되고 있는 실리카퓸을 적용하여 혼화재 치환에 따른 숏크리트의 장기 내구 특성을 평가하였다. 복합 열화 시험 결과 실리카퓸을 혼입한 숏크리트는 다른 배합에 비해 가장 양호한 결과를 나타냈고, 실리카퓸은 강도 증진 효과와 함께 강섬유 혼입에 의한 열화 현상을 최소한으로 감소시켜 숏크리트의 장기 내구성을 확보하는데 효과가 있었다.

• Tribology and Lubricants
• /
• 제34권5호
• /
• pp.197-207
• /
• 2018

Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

• Smart Structures and Systems
• /
• 제14권2호
• /
• pp.209-224
• /
• 2014

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy.

• 한국노년학
• /
• 제31권4호
• /
• pp.1047-1065
• /
• 2011

본 연구는 노인장기요양보험 대상자 및 등급 확대에 따른 대상자 규모와 소요 재정을 추계함으로써 제도의 안정적 발전 및 지속가능성을 제고하고, 향후 정책개발에 기초자료 제공을 목적으로 한다. 연구방법은 문헌조사와 독일, 일본 등 선험국의 대상자 확대 정책을 고찰하여 대상자 확대 전략을 수립하고, 국민건강보험공단의 노인장기요양보험 대상자 증가추이, 노인성 질환대상자 증가 추이 분석, 현행 등급별 대상자의 급여 현황을 파악하여 등급 확대에 따른 재정소요를 예측하였다. 구체적인 방법으로 대상자 및 4등급 확대를 위한 범위 또는 범주를 시나리오별로 구체화하고 세분화된 급여 수준을 분석하여 재정을 추계하였다. 분석결과 대상자는 2010년 31만명에서 2015년 최소 42만명, 최대 57만명이었고, 이에 따른 관리운영비를 제외한 재정은 2010년 2.5조에서 2015년 최소 3.6조, 최대 4.0조인 것으로 추계되었다. 결과적으로 4등급 확대 시기는 제도안정화와 선험국의 선례와 경험을 함께 고려할 때 도입 4년차인 2012년 또는 5년 차인 2013년이 적정할 것으로 보인다. 이로인한 재정은 확대 초기 약 3천억원에서 1조 4천억원이 급여수준에 따라 예측되고, 확대이후 4등급 인정자 및 필요 재정지출은 점차 줄어들 것으로 예측된다. 선험국의 예를 볼때 급격한 4등급 확대보다는 시설 및 인프라가 감당할 수 있고, 재정 부담이 가능한 범위 내에서 확대 규모를 도출하는 것이 바람직할 것으로 판단된다. 본 연구는 시의성 있는 연구를 제시하여 향후 정확한 대상자 확대 및 재정안정화를 추구하도록 방향성을 제시하였다.

• Journal of Information Technology Applications and Management
• /
• 제24권3호
• /
• pp.73-92
• /
• 2017

Usability is one of the most important concepts regarding software quality. It can be interpreted as the goodness associated with using the software product. This paper distinguishes the goodness of an individual using experience and the goodness of a product for using. This paper proposes a software quality view model which classifies software quality views into two broad categories of end view and means view. End view includes long-term view and short-term view which is classified further into performer's view on software activity and third party's view on software activity. Means view includes intrinsic view and contingency view. The analysis of ISO 25000 Series SQuaRE demonstrates the necessity to decompose product quality model and quality in use model into five models corresponding to the software quality views respectively. The analysis on playability shows that the universal definition of usability may be an illusion. The results provide the theoretical basis to build a comprehensive and consistent body of knowledge regarding software quality, which is consisted with the set of quality models and the theories explaining the relationships among the elements of the models.

• 한국인쇄학회지
• /
• 제30권1호
• /
• pp.59-69
• /
• 2012

This study is Long term preservation measures which is closely related to preserving paper records, record condition evaluation, preservation measure and is conducted as follows. As for Means to Evaluate the Deterioration and Damaged Conditions of Records, research and analysis has been made on the contamination and deterioration examples such as damage, dry, stapler, metal, contamination, acidification which are the characteristics of paper record damage types. The of Paper record is one of the key procedures to evaluate the record material and its physi-chemical status in many criteria and to suggest the best preservation method. Between 1970 and 2000, the main record materials was fine paper and OMR paper along with partly newspaper and coarse paper, whereas the main recording material was ball point pen. Overall damage and deterioration status is, for record materials between 1940 and 1960, high deterioration was found and in urgent need for preservation measure and more damages are caused by tapes, staplers and metals. As for records after 1970, there is light deterioration but needs preservation process. There are approximately 3 million records produces before 2000, and assuming that there are 30 pages per record and that 30% has been damaged or deteriorated, 27 million pages are subject to preservation process. Among damaged or deteriorated records, there are large number of records impossible to go through deacidification process so manual preservation and restoration process is necessary as well. Securing manpower having preservation and restoration skills as well as preservation equipment(deacidification process, preservation and restoration) is in urgent need.