• International journal of advanced smart convergence
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• 제4권1호
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• pp.54-63
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• 2015

Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

• 디지털융복합연구
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• 제12권1호
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• pp.273-280
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• 2014

본 연구는 페이스북과 같은 소셜미디어의 중독과 지속사용 의도에 관한 연구를 통해 디지털 정책의 대안을 제시하고자 한 연구이다. 이를 위해 연구자는 소셜미디어 사용자가 인식하는 중독 증상에 대해 선행과 후행의 변인을 찾아보고, 서비스 지속 이용에 대한 방안 및 중독의 예방을 위한 함의를 얻고자 하였다. 연구결과 1) 개인의 혁신성은 서비스 만족, 중독, 지속사용의도에 영향을 미치고, 2) 서비스 만족이 중독과 지속사용의도에 영향을 미치며, 3) 서비스 중독 인식이 지속사용 의도에 부정적인 영향을 미쳤다. 이 점은 이용자의 중독인지가 서비스의 지속 성장에 장애가 됨을 설명하는 결과였다. 본 연구의 정책적 제안은 다음 두 가지로 요약된다. 1) 서비스 제공사업자는 이용자가 중독적인 사용행태를 보일 때 이용자가 중독으로 인해 서비스로부터 이탈하지 않도록 주의를 기울여야 한다. 2) 정부는 서비스 중독의 예방을 위해 이용자가 중독으로 인한 불편함을 인지할 때 대처할 수 있는 치유시설, 서비스 등을 제공해야 할 것으로 기대된다.

• 셀메드
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• 제10권2호
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• pp.16.1-16.8
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• 2020

Standardization of drug deals with confirmation of drug identity and determination of drug quality and purity. Unani herbal formulations are used in traditional medicine for the treatment of various diseases. Cancer is a disease which causes abnormal, uncontrolled growth of body tissue or cells, which tend to proliferate in an uncontrolled way. Spread of cancer from site of origin to other organs of the body is called metastasis. It is a hyper proliferative disorder involving, transformation, dysregulation of apoptosis, invasion and angiogenesis. The present study aimed to standardize a classical Unani formulation (CUF) described as anticancer properties. The CUF has been used for anti-cancerous activity (Dāfi'-i-saraṭān) in human population by Unani physicians for centuries. The standardization parameters carried out for classical Unani formulation are pharmacognostical studies, physicochemical parameters, high-performance thin layer chromatography (HPTLC), microbial load, aflatoxins, and heavy metals revealing specific identities and to evaluate Pharmacopoeial standards. Experiment and the data obtained established the Pharmacopoeial standards for this formulation for identification and quality control purpose. The CUF has been successfully standardized and standard operating procedures (SOPs) for its preparation has been laid down which may serve as a standard reference in future. The standardization data of this formulation may be used as a standard guideline for preparation of the formulation in future.

• 한국작물학회지
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• 제41권spc1호
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• pp.123-144
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• 1996

This review deals briefly with the various medicinal components(mainly saikosaponins), their biological activities and the variation of their contents by different cultivation environment and plant parts in Bupleurum species. Bupleuri radix, a crude drug, is the root of Bupleurum falcatum L. (Korea, Japan), B. chinense(China), and their related species (Umbelliferae). There are over 120 species in Bupleurum genus throughout world, mainly Asian area, and over 5 species in Korea, investigated up to now. These plants contain many physiological active compounds and the principal components are saikosaponins. Major activities of this crude drug and saikosaponins are the anti-inflammatory and antihepatotoxic activities. Saikosaponins and their derivatives in Bupleurum spp. have been chemically studied, isolated and identified over 70 compounds in over 50 species. Other components, physiologically active ones, also have been investigated, which are the groups of lignan, flavonoid, essential oil, polyacetylene, polysaccharide, etc. Saikosaponins belong to the group of triterpenoid saponin chemotaxonomically and occur the accumulation and turnover in plant tissues through secondary metabolism, mevalonic acid pathway. The contents and kinds of saikosaponins and other components in Bupleurum spp. plants are various due to different species and growing environments, as the plant growth characters and yield are various. Most of medicinal plants as well as Bupleurum species are very useful as agricultural products and traditional medicines, and also are very valuable as genetic resources and natural products. So we need to collect, evaluate, preserve, and utilize various medicinal plants, and also to under-stand secondary metabolism and improve the breeding and cultivation techniques for the safe production of crude drugs with high quality and yielding.

• 한국도로학회논문집
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• 제13권2호
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• pp.77-83
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• 2011

이 연구는 회전교차로의 효과를 다루고 있다. 연구의 목적은 로터리를 회전교차로로 전환함에 따른 운영효과를 비교 분석하는데 있다. 이를 위해 이 연구에서는 국내에서 운영되고 있는 로터리 20개 지점을 조사하고, VISSIM을 통해 개선 전 후의 네트워크를 구축하며, 그 효과를 비교분석하는데 중점을 두고 있다. 국내의 로터리는 효과적인 회전교차로 운영을 위하여 기하구조 측면에서 많은 개선이 필요한 것으로 분석되었다. 연구의 주요결과는 다음과 같다. 첫째, 현재 교통량을 적용하였을 경우 로터리의 운영효과는 다소 좋은 것으로 나타나지만 그 차이는 매우 적은 것으로 평가되었다. 둘째, 도시부 로터리의 경우 교통량이 증가할수록 차량당 평균지체가 급격히 증가하는 것으로 분석되었다. 마지막으로 지방부의 경우 도시부에 비해 교통량이 적기 때문에 회전교차로의 평균속도는 로터리에 비해 약 10km/h의 속도저감효과를 갖는 것으로 평가되었다.

• 한국산학기술학회논문지
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• 제15권9호
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• pp.5564-5577
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• 2014

본 연구에서는 Price-Scaling AIDS 모형을 바탕으로 가구별 특성의 차이가 소비지출 구조에 어떠한 영향을 미치는지를 통계청 "가계동향조사" 자료를 이용하여 추정하였다. 추정결과, 서비스 품목들의 소득탄력성은 비서비스 품목들의 소득탄력성에 비해 상대적으로 큰 것으로 나타나 향후 가구소득이 늘어날 경우 서비스 품목들에 대한 더 큰 수요 증가가 예상된다. 또한 품목별 가계의 소비지출행태는 연령별, 소득수준별로 상이한 모습을 띠고 있는 것으로 나타났다. 특히, 비서비스 품목에 대한 지출비중이 높은 전통적인 가계지출구조에서 보건, 교육, 통신 등과 같은 서비스품목에 대한 지출비중이 높은 구조로의 전환이 촉진되고 있음이 확인되었다. 이와 같이 서비스품목에 대한 수요 증가로 인한 가계소비지출 구조의 변화는 관련 서비스 시장의 확대와 더불어 서비스 산업의 성장 잠재력을 더욱 확대시키는 방향으로 작용할 수 있다. 따라서 이들 분야에 대한 잠재수요 및 성장가능성에 대한 정확한 파악과 더불어 해당 서비스 시장의 형성 및 확대와 관련한 공급측의 적절한 대응이 요구된다.

• 한국항해항만학회지
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• 제36권1호
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• pp.51-58
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• 2012

크루즈 관광 산업은 모든 관광 산업 중 세계적으로 가장 빠르게 성장하고 있는 관광산업임에도 불구하고, 지금까지 합리적 크루즈 경영의사결정에 관한 학술적 연구가 매우 미진한 상황이다. 이 논문은 크루즈 경영에 관한 기초적인 전략적 의사결정이라고 할 수 있는 크루즈 운항일정계획을 다루고 있다. 이전에 개발된 한척의 크루즈선박에 관한 모형의 제한점을 극복하여, 여러 척의 크루즈선박으로 구성된 크루즈 선대를 일반적으로 다룰 수 있는 최적화 의사결정계획 모형을 개발하였다. 후보운항일정계획들 간의 복잡성을 체계화하기 위해 선박별 후보운항일정계획 네트워크를 제안하였으며, 후보운항일정계획 네트워크 전체를 통합하는 정수계획모형을 개발하였다. 공개된 크루즈 운항일정 자료들에 바탕을 둔 가상 사례를 활용하여 개발된 모형을 실험하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.661-667
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• 2002

Welding-induced buckling distortion is one of the most problematic concerns in both design and fabrication of welded thin-plate structures. This paper deals with experimental and numerical results of the welding-induced longitudinal and/or buckling distortion occurring in welding of 6mm-thick AH36 high strength steel plates. Effects of the heat input and the plate size on the distortion were experimentally evaluated for square plates. Bead-on-plate welding was performed with the submerged arc welding process along the middle line of plate specimens. Experimental results showed that the longitudinal distortion made a single curvature in the plate, and the distortion magnitude along the weld centerline was proportional to the heat input and the plate size. The experimental results were used to examine the validity of the numerical simulation procedure for welding-induced distortion where the longitudinal distortion mode and magnitude were numerically quantified. Three-dimensional, large deformation, welding simulations were performed for selected weld models. Numerical results of the distortion mode and magnitude were in a good agreement with experimental ones. Depending on the presence of halting the distortion growth during the cooling cycle of welding, the condition discriminating buckling distortion from longitudinal distortion was established. Eigenvalue analyses were performed to check the buckling instability of tested plates with different sizes subjected to different heat inputs. The perturbation load pattern for the analysis was extracted from longitudinal inherent strain distributions. Critical buckling curve from the eigenvalue analyses revealed that the buckling instability is manifested when plate size or heat input increases.

• Journal of Forest and Environmental Science
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• 제24권3호
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• pp.159-164
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• 2008

Forest inventory is a commercial term meaning the preparation of detailed descriptive list of articles with number, quantity and value of each item included. Forest inventory deals with the measurement of trees and stands, the estimation of their volume, growth prediction, biomass, carbon stocks and the description tree characteristics, as well as the land upon which they are growing. National Forest Inventory Center (NFIC) in Korea conducts national forest inventory every 5 years to obtain accurate baseline data for national forest policy. The permanent sample plot data used in were collected by NFI. The objective of this study was to develop methods for quantifying forest resources at national scale based on $5^{th}$ National Forest Inventory (NFI) data in Korea. Forest land area decreased from 6.44 to 6.38 million ha between 1997 and 2007, continuing a slight downward trend in area beginning in the late 1990s. However forest resources of the Korea have continued improving in general condition and quality, as measured by increased average size and volume of trees. Growing-stock volume of the Korea increased from 17 to 123.79 cubic meter per ha between 1976 and 2007. The biomass in Korea was estimated to be 153.81 tons per hectare and carbon stocks in Korea was estimated to be 84.36 tons per hectare by NFI data. This information is important for government officials, public administration, the private business sector, and the researcher. Forest Inventory should be implemented in a way to be able to monitor and assess the forests continuously.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1528-1534
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• 2001

In order to improve Leak-Be(ore-Break methodology, more precisely the crack growth evaluation, a round robin analysis was proposed by the CEA Saclay. The aim of this analysis was to evaluate the crack initiation life, penetration life and shape of through wall crack under cyclic bending loads. The proposed round robin analysis is composed of three main topic; fatigue crack initiation, crack propagation and crack penetration. This paper deals with the first topic, crack initiation in a notched pipe under four point bending. Both elastic-plastic finite element analysis and Neuber's rule were used to estimate the crack initiation life and the finite element models were verified by mesh-refinement, stress distribution and global deflection. In elastic-plastic finite element analysis, crack initiation life was determined by strain amplitude at the notch tip and strain-life curve of the material. In the analytical method, Neuber's rule with the consideration of load history and mean stress effect, was used for the life estimation. The effect of notch tip radius, strain range, cyclic hardening rule were examined in this study. When these results were compared with the experimental ones, the global deformation was a good agreement but the crack initiation cycle was higher than the experimental result.