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        검색결과 21

        1.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 운전상황에서 운전자의 스트레스가 유발되었을 시, 다감각 자극이 운전자의 스트레스 저감 효과에 미치는 영향을 분석하였다. 본 연구에서는 운전상황의 운전자의 스트레스를 저감을 목적으로 조명과 사운드 및 향의 조합을 통한 다감각 자극을 제시함으로써, 스트레스 저감에 대한 효과를 확인하고자 하였다. 운전 시 스트레스 상황을 정의하고, 두 종류의 스트레스 유발 시나리오를 구성하였다. 실험은 신체 건강한 20-50대 남녀 30명을 대상으로, 10분간 의 운전 상황을 연출하였다. 스트레스 저감에 효과적인 자극조합을 확인하기 위해 시각, 청각, 후각의 자극을 이용하였 으며, 시각 자극의 경우 LED 조명을 이용하여 블루, 그린, 옐로우 색상을 제시하였으며, 청각 자극은 화이트, 핑크, 브라운노이즈 사운드를, 후각 자극의 경우는 로즈마리, 라벤더, 레몬향을 각각 사용하였다. 또한, 스트레스 저감에 대한 효과를 살펴보기 위해, 다감각 자극 제시 전후로 주관평가 및 심박변이도를 측정하였다. 심장 반응의 결과, 그린(조 명), 핑크노이즈(사운드), 로즈마리(향)의 자극 조합에서 HF(%) 증가 및 LF(%), LF/HF(%)의 감소를 확인할 수 있었으 며, 이는 부교감반응의 활성화가 이루어짐을 알 수 있었다. 주관평가 또한 다감각 자극에 노출되었을 때, 다감각 자극이 없는 경우보다 스트레스 저감 효과가 있는 것으로 확인되었다. 이러한 결과는 다감각 자극에 노출되기 전보다 다감각 자극을 경험할 때 운전시 스트레스 저감에 효과를 보이는 것으로 사료된다. 향후 연령별이나 성별에 대한 차이나 개인이 선호하는 자극에 대한 연구를 통해 맞춤형 스트레스 저감 자극에 대한 효과를 확인하는 것이 필요하다.
        4,000원
        2.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The object of this study conducted to investigate the effect of paddy-upland rotation cropping system on soil properties and crop productivity in newly reclaimed tidal land. Five types of paddyupland rotation cropping system were evaluated : Rice-Rice (RR) Rice-Maize (RM), Mize-Maize (MM), Rice-Soybean (RS), Soybean-Soybean (SS). The soil bulk density was the lowest RM treatment, and soil pH was a tendency to be lower in all treatments of the paddy-upland rotation cropping system. RM treatment showed a higher moisture content and lower Electrical conductivity than RR treatment. Results of maize productivity in paddy-upland rotation cropping system, Except for the stem diameter growth, RM treatment showed good growth and productivity than MM treatment. Soybean growth and yield increased in the rotated upland cultivation from rice-paddy field compared to the SS treatment. But, overall treatments indicated poor growth and yield. In this study, we offer the effects of paddyupland rotation cropping system on the soil properties and upland crop growth and yield, and also out results can be provide supporting basic data that introduced paddy-upland rotation in reclaimed tidal land.
        4,000원
        3.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Soil salinity is the most critical problem at reclaimed tidal saline soil in Korea. The objective of this study was carried out investigate the salt movement in upland soils at Gyehwa-do region in Saemangeum reclaimed land on the south Korea coasts. The experiment was conducted 5% sloped polt (3.0 m × 10.0 m) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and K+was lower than that of Na and Mg. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio (SAR) and anion (Cl−, SO4 −) contents in soil were repressed in the order of vinyl-mulching > Rice straw-mulching > control plot. Our results indicate that soluble salt control is critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damages at reclaimed tidal saline soil in Korea.
        4,000원
        4.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Soil salinity at newly reclaimed land in west coast of Korea is highly variable and depending on soil characteristics and weather conditions. The objective of this study was to evaluate the spatiotemporal distribution characteristics changes on soil electrical conductivity and exchangeable sodium percentage in Saemangeum newly reclaimed land. Experimental sites was selected at Gyehwa (35o75'N, 126o60'E) in Saemangeum reclaimed land and their dominant soil series was Munpo (coarseloamy, mixed, non-acid, mesic, typic Fluvaquents). Soil samples were periodically collected at 0 ~ 20 cm and 20 ~ 40 cm layer from each site. Soil electrical conductivity had a wide range from 0.15 to 41.76 dS/m, which was variable according to the weather conditions. The average soil electrical conductivity from March 2014 to 2015 was 6.4 and 3.4 dS/m at Gyehwa in Seamangeum reclaimed land. Calcium concentration in soil solution was negatively correlated with soil electrical conductivity and soluble sodium. Soluble sodium concentration had great variations and it was the most influencing single factor for temporal variations of soil electrical conductivity regardless of soil textural properties. The characteristics of Saemangeum reclaimed land had different shares of saline and sodic properties during the experimental period. Our results indicate that persistent monitoring and modeling on soil salinity at coastal tide land is fundamental and the results can provide some useful information for deciding management plans for diverse utilization or to reduce salt damage for stable crop production at reclaimed tidal land.
        4,000원
        5.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        간척지에서 자생하는 자귀풀은 콩과잡초로서 휴먼성이 강하 고 종피가 딱딱한 껍질에 싸여있어 채종한 종자는 발아율이 저조하므로 발아율을 높이기 위하여 황산, 온도 및 모래를 을 이용한 종피파상 방법을 이용한 휴면타파 효과를 구명하기 위 하여 본 시험을 수행하여 그 결과는 다음과 같다. 1. 2013년도 간척지에서 채종한 자귀풀 발아세와 발아율은 18.0%와 27.0%, 2014년 채종 종자는 15.8%와 21.5%을 보였다. 2. 자귀풀 종자의 황산처리효과는 황산용액 50% 처리에서 는 무 처리와 큰 차이를 보이지 않았지만, 황산용액 100% 처 리에서는 채종 연도와 관계없이 71.0% ~ 73.0%의 발아율을 나 타내었다. 3. 온도처리 효과는 90oC 고온 상태에서 각각 20, 30, 40분 처리시의 발아율은 처리시간 40분에서 90% 이상의 높은 발아 율을 보여 처리시간이 길어질수록 발아율은 증가할 것으로 사 료된다. 4. 모래를 이용한 종피파상 처리는 2014년 채종한 종자는 종자량과 모래의 비율이 4배 처리에서 94.0%로 가장 높은 발 아율을 보였고, 2배 처리에서도 80%의 발아율을 나타내었다. 이상의 결과를 종합하면 간척지에서 채종한 자귀풀의 휴면 타파는 많은 노력이나 시설 및 비용이 추가되는 온도처리나 황산처리보다 주변에서 쉽게 구할 수 있는 모래를 이용한 종 피파상법이 좋을 것으로 사료된다.
        3,000원
        6.
        2015.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 새로 조성된 간척지에서 사료맥류 종자의 안정생산을 위한 적정 파종량을 구명코자 2011년부터 2013년까지수행하였다. 청보리와 트리티케일은 ha당 200, 300 및 400 kg호밀과 귀리는 ha당 100, 200 및 300 kg을 파종하고 토양화학성과 작물별 수량성을 조사 하였다. 사료맥류의 출현율과 입모율은 호밀, 트리티케일, 청보리, 귀리 순으로 높았다. 사료맥류 종실의 질소 함량은 트리티케일, 호밀, 보리, 귀리 순으로높았고 트리티케일과 호밀은 파종량 증가에 따라 질소함량이높아지는 경향을 나타냈다. 사료맥류의 종실수량은 트리티케일, 귀리, 호밀, 청보리 순으로 많았다. 파종량에 따른 종실수량은 청보리와 트리티케일은 ha당 300 kg에서, 호밀과 귀리는200 kg에서 많았다. 수량구성요소 중 m2당 이삭수가 종실수량에 큰 영향을 미쳤고 수당립수와 천립중은 파종량 감소에 따라증가하는 경향을 나타냈다. 연구 결과 새로 조성된 간척지에서동계 사료맥류 종자의 안정생산을 위한 적정 파종량은 ha당 청보리는 320 kg, 트리티케일은 290 kg, 호밀은 220 kg, 귀리는210 kg으로 나타났다.
        4,000원
        7.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The worldwide conversion of natural lands into urban land uses is the most significant process affecting landscape character and ecological conditions. The aim of this research was to analyze the changes of landscape character and ecological conditions to provide comprehensive information to assist policy makers in meeting wider sustainability objectives in an urban fringe landscape. The result indicated that the landscape experienced the decrease in woodland cover (-22.70%) and agricultural land cover (-10.30%) between 2002 and 2014. However, the urban land cover sharply increased from 5.07% in 2002 to 38.07% in 2014. Due to their location on the edge of the core urban area, this landscape character unit had been under increasing pressure from new built developments. Development pressures include housing expansion from adjoining urban areas, and business developments particularly associated with key road intersections and expansions of public infrastructure. Furthermore, the landscape had been changing rapidly as massive high-rise apartment developments were built as the core urban area expands, with the removal of woodlands and arable fields. These landscape changes in the study area had a strong impact on landscape character for this period. The index of landscape heterogeneity declined from 0.802 in 2002 to 0.712 in 2014. The index of area weighted mean woodland patch shape was decreased from 3.196 in 2002 to 2.784 in 2014. The result suggested that it became a more homogeneous landscape and had less species and a less stable ecological structure for this period. This research only used the index of landscape heterogeneity for landscape ecological analysis. For more ecological information, a more comprehensive analysis based on landscape ecological metrics is needed in future researches.
        4,000원
        8.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 경산시에 위치한 저수지를 대상으로 귀화식물의 현황 특징을 파악하여 적절한 미래관리방안을 모색하기 위한 기초자료를 제공하는데 그 목적이 있다. 경산시 일대의 저수지 식물현황 분석결과 62과 126속 148종 13변종 2품종으로 전체 164분류군으로 나타났다. 연구 대상지에 분포하는 귀화식물은 9과 19속 22종 1변종으로 총 23분류군을 확인하였다. 23분류군 중 원산지는 북아메리카가 15분류군, 유럽이 5분류군, 아프리카가 2분류군, 아시아가 1분류군으로 나타났다. 귀화율은 12.2%이며, 도시화지수는 2.1%이다. 이 결과는 Go(1995)이 제시한 우리나라 평균 귀화율 10.3%보다 높은 수치를 보였다. 마지막으로, 연구 대상지에서 나타난 저수지 생태계에 악영향을 줄 수 있는 귀화도가 4등급이상인 14분류군(소리쟁이, 콩다닥냉이, 토끼풀, 달맞이꽃, 서양민들레, 개망초, 돼지풀, 미국쑥부쟁이, 큰비짜루국화, 미국가막사리, 가시상추, 미국개기장)등 을 중점적인 관리대상으로 선정하여 적절한 관리방안과 지속적인 모니터링이 필요할 것으로 사료된다.
        5,100원
        9.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농촌지역 발전 및 주민의 삶의 질 향상을 위해 추진된 정부의 다양한 정책 및 사업의 성과를 분석하기 위해 현재 추진 중에 있는 농촌지역개발사업 중 대표성이 있다고 판단되는 농촌마을종합개발사업을 분석대상 사업으로 선정하였다. 분석을 위해 경남 2개 권역과 전남 2개 권역을 사례연구대상권역으로 선정하였다. 사업에 대한 만족도 분석결과, 전체적으로 사업추진에 있어서 각 지역유형별로 명확한 구분을 통해 만족도를 분석하는 것은 상당한 어려움이 있으나, 전반적으로 지역특성별(농촌지역, 중산간지역)로 주민들의 사업에 대한 이해 및 추진과정에서의 만족도 등은 다소 차이가 있음을 확인하였다. 또한, 전반적으로 농촌지역 2개 권역 주민들이 중산간지역 2개 권역 주민들에 비해 상대적으로 사업 추진 전반에 대해 부정적인 의견을 많이 표출하였다. 향후 원활한 사업추진을 위해서는 주민들의 사업에 대한 이해, 서로 돕고 협력하는 마을 공동체 의식의 복원, 바람직한 리더 육성, 실효성 있는 마을 규약 마련, 개방적·포용적 자세로의 전환과 농촌마을종합개발사업 추진 및 운영방법의 현실화가 필요할 것으로 판단된다.
        4,000원
        10.
        2011.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 주간동안 온실 내에서 발생되는 잉여 태양에너지를 분석하고, 또한 잉여 태양에너지의 적정 축열 시스템 설계에 필요한 기초자료를 제공할 목적으로 수행하였다. 분석에 이용된 기상자료는 표준기상년 데이터로서 이용하여 국내 주요 지역을 대상으로 온실 형태별로 잉여 태양에너지를 분석하였을 뿐만 아니라 소요 난방에너지 등도 분석 및 검토하였다. 이상의 결과를 요약하면 다음과 같다. 9개 지역을 대상으로 지역별 잉여 태양에너지를 대해 분석한 결과, 난방에너지 대비 잉여 태양에너지 비율은 온실 형태별로 각각 약 212.0~228.0%로서 제주가 가장 높게 나타났다. 그 다음으로 부산, 광주, 진주, 대구, 대전, 전주, 수원, 및 대관령 순으로 나타났다. 그리고 온실 형태에 관계없이 몇 몇 지역을 제외 하면 잉여 태양에너지만으로 소요 난방에너지를 거의 대체할 수 있을 것으로 판단되었다.
        4,000원
        11.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 지금까지 추진되어 왔던 전통테마마을 사업의 추진성과를 분석하기 위해 인적 요소, 경제적 요소, 사회적 요소 등으로 구성된 평가지표를 개발하였다. 평가지표에 대한 객관성을 확보하기 위해 전 문가를 대상으로 AHP법을 이용하여 중요도 평가를 실시하였다. 평가지표의 중요도는 주민만족도 (150), 주민참여도 (145), 경제적효과 (123), 민박가구수 (101), 리더양성정도 (96), 사업이해도 (90) 순으로 나타났 다. 6개 마을에 적용한 결과, 해바리마을, 다랭이마을, 남사예담촌, 물레방아떡마을, 산첩렵마을 순으로 평가량이 산정되었다. 농촌마을 간의 균형적인 발전을 도모하기 위해 인적 측면, 경제적 측면, 사회적 측 면에서 개선방안을 제시하였다.
        4,300원
        13.
        2019.12 KCI 등재 서비스 종료(열람 제한)
        Common reed (Phragmites australis) is widespread in reclaimed land and wetland habitats. Every year, the common reed produces extensive colonies by means of underground rhizomes and ground-surface stolons. From an agricultural point of view, the common reed's large biomass is a good material for supplying organic matter. However, it has not yet been studied in terms of seedling production, transplanting conditions, and decomposition characteristics in reclaimed land. Seeds were harvested from the native common reed in Saemangeum, South Korea, the previous year and stored on an open field. The seeds were sowed in the greenhouse at the beginning of April. Common reed decomposition was studied from June to September, with the use of coarse mesh (5 mm) stem litterbags, on three samping dates and with five replicate packs per sample. These packs were dug in five soil condition (low-salinity topsoil, subsoil, high-salinity topsoil, subsoil, paddy topsoil) to 0.2 m and 0.4 m depth. The highest germination rate of common reed seeds was observed in non-salt solution, but the exhibited germination rate was 70% at 9.38 dS m-1. The plant height of young reed decreased steadily with increasing salinity, but leaf number did not decrease by 9.38 dS m-1. The survival rate of the two-year-old reed was 83.3%, which was 35% higher than that of the one-year reed. The transplant success rate was 0% in the no vinyl mulching in the soil, but the first year and second year seedlings survived rates were 63% and 83.3%, respectively, in vinyl mulching. Common reed decomposition rates were faster low salinity than high salinity. All nutrient contents were found to fluctuate significantly with time by soil conditions. We also need to study the growth rate of reed transplanting seedlings by soil moisture contents and the comparison of degradation in common reed tissues.
        14.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        Paddy-upland rotation system is one of the important cropping system for improving soil quality and crop productivity. we conducted to investigate the effect of paddy-upland rotation system on soil properties and crop productivity in reclaimed tidal land. The paddy-upland rotation could be effective to conserve soil water contents and prevent from salt damage when cultivating upland crops. The first two years of maize cultivation after rice cultivation could be effective to secure stable production. However, in case of soybean crop, the rotation effect might be lower than that of maize. In the first year, the yield of soybean was 214 kg/10a. In the second and third year, the yields of soybean decreased consecutively to 152, 123 kg/10a respectively. In this paper, it would be suggested that maize be cultivated for up to two years and soybean be cultivated for one year after rice crop grown in reclaimed tidal land. This study could be provide basic data of the physico-chemical properties applicable to paddy-upland rotation system at reclaimed tidal lands.
        15.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        To ensure the successful launch of the Korea pathfinder lunar orbiter (KPLO) mission, the Korea Aerospace Research Institute (KARI) is now performing extensive trajectory design and analysis studies. From the trajectory design perspective, it is crucial to prepare contingency trajectory options for the failure of the first lunar brake or the failure of the first lunar orbit insertion (LOI) maneuver. As part of the early phase trajectory design and analysis activities, the required time of flight (TOF) and associated delta-V magnitudes for each recovery maneuver (RM) to recover the KPLO mission trajectory are analyzed. There are two typical trajectory recovery options, direct recovery and low energy recovery. The current work is focused on the direct recovery option. Results indicate that a quicker execution of the first RM after the failure of the first LOI plays a significant role in saving the magnitudes of the RMs. Under the conditions of the extremely tight delta-V budget that is currently allocated for the KPLO mission, it is found that the recovery of the KPLO without altering the originally planned mission orbit (a 100 km circular orbit) cannot be achieved via direct recovery options. However, feasible recovery options are suggested within the boundaries of the currently planned delta-V budget. By changing the shape and orientation of the recovered final mission orbit, it is expected that the KPLO mission may partially pursue its scientific mission after successful recovery, though it will be limited.
        16.
        2017.04 KCI 등재 서비스 종료(열람 제한)
        본 논문은 게임에 대한 사용자의 직접적인 행동제어 방법보다는 사용 습관의 변화에 대한 적절 한 보상을 제시함으로 올바른 사용을 유도하고자 하였다. 본 연구에서는 제시된 보상의 몰입 효과 를 분석하여 보상 효과를 검증하였다. 24명의 초등학생들이 실험에 참여하였다. 피험자에게 제공 한 태스크(task)는 산술 게임이며, 결과에 따라 4종류의 보상(보상없음, 칭찬카드, 업적 스티커, 현 금)의 효과를 분석하였다. 산술 게임하는 동안에는 심장 반응과 보상에 대한 주관 만족도를 측정 하였다. 결과적으로, 보상이 없는 경우는 교감, 부교감의 비활성화를 나타내었으며, 칭찬카드를 제 시했을 경우, 교감 및 부교감 활성화를 확인하였다. 즉, 칭찬카드가 다른 보상보다도 가장 몰입 및 만족도가 크다는 것을 확인할 수 있었다. 하지만, 보상에 따른 주관적인 만족도에서는 보상없음과 보상을 제시한 경우의 통계적 유의한 차이는 있었지만, 보상간의 차이는 확인할 수 없었다.
        17.
        2016.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the 1st lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the 1st LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the 1st LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the 1st elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center, are expected to be prepared and established based on the current results, including a contingency trajectory design plan.
        18.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        This experiment was conducted to identify the variations in inorganic nutrients and plant growth in millet (Panicum miliaceum L.) due to soil salinity. The soil series was Munpo and soil texture was silt loam. The experimental soil was amended so that the soil had salinities of 0.8 dS m-1, 1.6 dS m-1, 3.2 dS m-1 and 4.8 dS m-1. Millet was transplanted 15 days after sowing. As soil salinity increased, the degree of reduced growth was in the order of seed production > root dry matter > plant dry matter > culm length > tiller number > stem thickness > Panicle length. Seed production was decreased to 18.9% in soil salinity of 1.6 dS m-1, 36.9% in of 3.2 dS m-1, and 50.7% in EC of 4.8 dS m-1. Root dry matter decreased to 35.8% in EC of 3.2 dS m-1, and to 40.5% in EC of 4.8 dS m-1. As soil salinity increased, Total nitrogen content increased in all aboveground parts, roots and seeds. However, There was no difference in CaO, P2O5, K2O and, MgO in soils of different salinity. On the other hand, Na2O content was higher in the order roots> shoots> seed, and in the case of roots, Na2O content increased to 1.02% in soil salinity of 4.8 dS m-1. However, up to soil salinity of 1.6 dS m-1, the Na2O content of the seed was similar to that in plant grown in the Control conditions(0.8 dS m-1). In conclusion, taking into consideration economic factors, millet could be cultivated in soil with salinities of up to approximately 1.6 dS m-1, and seed produced from reclaimedland would be suitable for human consumption.
        19.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Characteristics of delta-V requirements for deploying an impactor from a mother-ship at different orbital altitudes are analyzed in order to prepare for a future lunar CubeSat impactor mission. A mother-ship is assumed to be orbiting the moon with a circular orbit at a 90 deg inclination and having 50, 100, 150, 200 km altitudes. Critical design parameters that are directly related to the success of the impactor mission are also analyzed including deploy directions, CubeSat flight time, impact velocity, and associated impact angles. Based on derived delta-V requirements, required thruster burn time and fuel mass are analyzed by adapting four different miniaturized commercial onboard thrusters currently developed for CubeSat applications. As a result, CubeSat impact trajectories as well as thruster burn characteristics deployed at different orbital altitudes are found to satisfy the mission objectives. It is concluded that thrust burn time should considered as the more critical design parameter than the required fuel mass when deducing the onboard propulsion system requirements. Results provided through this work will be helpful in further detailed system definition and design activities for future lunar missions with a CubeSat-based payload.
        20.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this work, an efficient method with which to evaluate the high-degree-and-order gravitational harmonics of the non-sphericity of a central body is described and applied to state predictions of a lunar orbiter. Unlike the work of Song et al. (2010), which used a conventional computation method to process gravitational harmonic coefficients, the current work adapted a well-known recursion formula that directly uses fully normalized associated Legendre functions to compute the acceleration due to the non-sphericity of the moon. With the formulated algorithms, the states of a lunar orbiting satellite are predicted and its performance is validated in comparisons with solutions obtained from STK/Astrogator. The predicted differences in the orbital states between STK/Astrogator and the current work all remain at a position of less than 1 m with velocity accuracy levels of less than 1 mm/s, even with different orbital inclinations. The effectiveness of the current algorithm, in terms of both the computation time and the degree of accuracy degradation, is also shown in comparisons with results obtained from earlier work. It is expected that the proposed algorithm can be used as a foundation for the development of an operational flight dynamics subsystem for future lunar exploration missions by Korea. It can also be used to analyze missions which require very close operations to the moon.
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