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        검색결과 223

        141.
        2019.06 KCI 등재 서비스 종료(열람 제한)
        In this study, we developed an FSEA(Force-sensing Series Elastic Actuator) composed of a spring and an actuator has been developed to compensate for external disturbance forced. The FSEA has a simple structure in which the spring and the actuator are connected in series, and the external force can be easily measured through the displacement of the spring. And the characteristic of the spring absorbs the shock to the small disturbance and increases the sense of stability. It is designed and constructed to control the stiffness of such springs more flexibly according to the situation. The conventional FSEA uses a fixed stiffness spring and the actuator is not compensated properly when it receives large or small external force. Through this experiment, it is confirmed that FSEA compensates the external force through the proposed algorithm that the variable stiffness compensates well for large and small external forces.
        142.
        2019.06 KCI 등재 서비스 종료(열람 제한)
        The optimal grasping point of the object varies depending on the shape of the object, such as the weight, the material, the grasping contact with the robot hand, and the grasping force. In order to derive the optimal grasping points for each object by a three fingered robot hand, optimal point and posture have been derived based on the geometry of the object and the hand using the artificial neural network. The optimal grasping cost function has been derived by constructing the cost function based on the probability density function of the normal distribution. Considering the characteristics of the object and the robot hand, the optimum height and width have been set to grasp the object by the robot hand. The resultant force between the contact area of the robot finger and the object has been estimated from the grasping force of the robot finger and the gravitational force of the object. In addition to these, the geometrical and gravitational center points of the object have been considered in obtaining the optimum grasping position of the robot finger and the object using the artificial neural network. To show the effectiveness of the proposed algorithm, the friction cone for the stable grasping operation has been modeled through the grasping experiments.
        143.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to investigate the changes in the amount of 20 free amino acids in PDB (Potato Dextrose Broth) medium during the incubation period while cultivating Lentinula edodes. The total incubation period was 90 days, and the total amount of free amino acids was confirmed every 45 days. Among the 18 kinds of amino acids whose increase and decrease patterns were confirmed, 10 amino acids were increased compared to that in the control, among which cysteine increased from its initial value of 9,889 ± 3 μg/L to 12,909 ± 2 μg/L at 45 days and 29,256 ± 4 μg/L at 90 days. Six amino acids with decreased expression patterns were identified. Arginine decreased to 83,751 ± 2 μg/L after 45 days from its initial value of 161,787 ± 1 μg/L and to 79,055 ± 7 μg/L at 90 days.
        144.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        This study investigated the relationship among seven species of trichoderma through the identification of strains collected in Korea. The phylogenetic tree among the collected strains was classified into four groups. The trichoderma strains isolated in this way showed inhibitory effect on the fusarium wilt which is parasitic to cotyledon stem..The invisibility of J9, J10, J13 and J16 strains were higher in comparison with other strains in vitro test stand, and their spore production level was also higher. In the aluminum ring tests, it showed that the yield of the spores in J9, J10 and J13 were more than any other strain. As a result conducting the port test for cucumbers, the plant lengths of J13 were larger than the control plot, and the root lengths of all strains, except for J2 were longer than the control plot, and the root weights of J1, J9, J10, J13 and J16 were larger than the control plot. The disease severity for the fusarium wilt showed the smallest values at J13 and J16 in comparison with the control plot, and the control values of J13 and J16 were higher than other strains.
        145.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        In this paper, we propose an algorithm that estimates the location of lunar rover using IMU and vision system instead of the dead-reckoning method using IMU and encoder, which is difficult to estimate the exact distance due to the accumulated error and slip. First, in the lunar environment, magnetic fields are not uniform, unlike the Earth, so only acceleration and gyro sensor data were used for the localization. These data were applied to extended kalman filter to estimate Roll, Pitch, Yaw Euler angles of the exploration rover. Also, the lunar module has special color which can not be seen in the lunar environment. Therefore, the lunar module were correctly recognized by applying the HSV color filter to the stereo image taken by lunar rover. Then, the distance between the exploration rover and the lunar module was estimated through SIFT feature point matching algorithm and geometry. Finally, the estimated Euler angles and distances were used to estimate the current position of the rover from the lunar module. The performance of the proposed algorithm was been compared to the conventional algorithm to show the superiority of the proposed algorithm.
        146.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        Background: The growth process of ginseng seedlings is very important in producing good quality ginseng. This study was carried out to investigate the effects of different microclimates on the growth characteristics of ginseng seedlings in a multi-layer bed facility. Methods and Results: Ginseng seedlings were cultivated in a three-layer bed facility. The air temperatures on the first and second floors were similar, while that on the third floor was about 1 - 4℃ higher than that on the other floors. The vapor pressure deficit (VPD) was higher inside than on the outside of the facility, and that on third floor was the highest in the multi-layer bed system. The photosynthetic rate, chlorophyll fluorescence, and growth characteristics of ginseng seedlings did not significantly differ among the three floors. The yield of ginseng seedlings was the highest at 721 g/1.62 ㎡ on the first floor Conclusions: It was found that microclimate plays an important role in growing ginseng seedlings in multi-layer bed facilities, and therefore proper environmental control is important. In addition, producing ginseng seedlings using multi-layer bed facilities is a technology that is expected to provide a way to overcome climate change and stabilize ginseng production.
        147.
        2018.10 서비스 종료(열람 제한)
        Background : Ginseng (Panax ginseng C. A. Meyer) is a multi-year-cultivated plant that causes many insects and disease damage during the growing season. The Ginseng Rain-sheltered Shade House is one of the efficient cultivation techniques as reducing the damages caused by natural disaster such as blight, high temperature & humidity, dry, and heavy rain & snow. This study was conducted to investigate the growth characteristics of 4-years-old ginseng using rain-sheltered shade house suitable shading materials for the Gyeongsangbuk-do. Methods and Results : The rain-sheltered shade house shading materials were PE film with layered polyethylene net 90%, Light diffusion film with layered polyethylene net 75%, blue-white duplicated film. In order to determine proper shading materials of the rain-sheltered shade house, ginseng growth characteristics such as plant length, stem diameter, leaf length, root length and root diameter were investigated at 4-years-old ginseng. As a result, the evaluations of aerial part growth by measurements were good in the following order: PE film + polyethylene net 90%, Blue-white duplicated film and light diffusion film + polyethylene net 75%. The evaluations of root weight by measurements were heavy in the following order: Blue-white duplicated film, PE film + polyethylene net 90% and light diffusion film + polyethylene net 75%. The net photosynthetic rate was higher in blue-white duplicated film than other shading materials treatments during growth season including summer high-temperature period. Conclusion : In the 4-years-old ginseng cultivation in Gyeongsangbuk-do using the rain-sheltered shade house, aerial part growth in PE film + polyethylene net 90% was better than other shading materials. In addition, root weight in Blue-white duplicated film was heavier than other shading materials. It will be possible to know which shading material is the most suitable for Gyeongsangbuk-do area after further growth.
        148.
        2018.10 서비스 종료(열람 제한)
        Background : Foliar fertilizer materials are used in the field of ginseng farming to enhance the growth of ginseng. The law for ginseng industry prohibits the use of chemical fertilizer as a material for growing ginseng, but in recent years, various organic materials derived from natural materials have been produced and used in farming sites. The purpose of this study was to investigate the effects of foliar fertilizer on the growth and soil properties of ginseng during continuous use. Methods and Results : For the test materials, native seedlings were used and the amino acid solution, liquid silicate, microbial liquid and fermentation enzyme were treated from 2 to 5– year-old ginseng after transplantation. The test plots were carried out to 3 repetitions by randomized block design. The area of one plot was 3.24 ㎡. The treatments were foliar application three times at intervals of 10 days from the late of May when leaf development was completed. The chemical properties of each foliar fertilizer pH was the highest at 9.63 for liquid silicate and lowest at 5.85 for amino acids. Ammonium nitrate had the highest amino acid content (56 ㎎/ℓ). Phosphorus was the highest with 113.7 ㎎/ℓ of fermentation enzyme. As a result of foliar fertilization for 4-years up to 5-years of ginseng, the pH was similar in soil chemical properties. EC and nitrate nitrogen contents tended to be higher in foliar application than in non-treatment. In the photosynthesis of ginseng, fermentation enzyme and microbial treatment tended to be high. Thickness of ginseng leaf was the thickest in microbial treatment. Microbial treatment was the highest in the underground part. Soil chemical properties were also affected but there was no significant change to inhibit the growth of ginseng. Conclusion : The treatments of the foliar fertilizer were more effective than the no treatment on the growth of ginseng. Among the foliar fertilizers distributed on the market, those derived from natural products can be used in ginseng cultivation.
        149.
        2018.10 서비스 종료(열람 제한)
        Background : The chlorophyll fluorescence imaging as non-destructive imaging methods have been used widely for efficiently early detection of plant responses to various stresses. The information from images acquired from different condition has the potential to generate specific signatures for particular stresses. Light-energy absorbed by plants is distributed over three competing processes: photosynthesis, thermal dissipation and chlorophyll fluorescence emission. An increase in Chl-FI thus implies a decrease in photosynthesis. The stresses in growing stage will change the efficacy of photosynthesis. As a example, Chl-FI of plant infections was carried out previously for a number of different viral and fungal plant–pathogen systems. Therefore, image can be used for differentiation of various stress index. Methods and results : 2-years-old ginseng plants were transplanted to plastic pots and each stress factors were treated. The stress factors used in this study were high temperature, low temperature, fungicide, and fungal pathogen. High temperature stress was induced by placing pots inside incubator adjusted at 35℃. For treatment of low temperature stress, ginseng plants were stored at 5℃ refrigerator for 5 minutes. Pathogen stress was carried to inoculate mycelial disk. Alternaria panax was inoculated potato-dextrose-medium and cultured for 10 days at 25℃. Mycelial disk obtained from cultured plate were placed on the one leaf of ginseng. Azoxystrobin wp was diluted 500, 1,000 times in tap water and sprayed to ginseng plants. Chlorophyll fluorescence image was acquired from each plant that stress treated and analyzed with sigma plot software. Conclusion : Important value, Fv/Fm (maximum efficiency of photosystem II), Fp (peak fluorescence during the initial phase of the operating efficiency of the Kautsky effect), NPQ-lss (steady-state, non-photochemical), etc., were significantly changed by variable stress index. But it was impossible to differentiate kind of stress by acquired value.
        150.
        2018.05 서비스 종료(열람 제한)
        Background : Multi-stage system were used for development of stable ginseng seedling production. Bed-soil for the production of ginseng seedling in the multi-stage was similar to the conventional bed-soil but the weight of the bed-soil was high and the efficiency of operation in the multi-stage was lowered. In this study, the yield and quality of ginseng seedling was investigated by commercial lightweight bed-soil in the multi-stage facilities, and the possibility of application of lightweight bed-soil. Methods and Results : This study was carried out by a 3-stage cultivation bed using a 50 ㎜ sandwich panel in a house shaded with 85% light-shielding net. The width of the cultivating bed was 90 ㎝, the height was 30 ㎝, and the height of each stage was 50 ㎝. In the first and second stages, the amount of light was insufficient, so two rows of fluorescent lamps were installed and the third stage was used natural light. Ginseng seeds were sown on the cultivating bed in November 2016, and ginseng seeds (native species) were sown with a density of 3 × 3 ㎝. The chemical properties of lightweight bed-soil were pH 5.11, and EC 0.76 dS/m. It was suitable for ginseng seedling cultivation. The bulk density was 0.21 Mg/㎥. Among the growth characteristics of the ginseng seedlings, the root length was the longest as 17.0 ㎝ in the conventional cultivation, and the second stage was the longest at 14.8 ㎝ in the multi-stage facility. The root diameter in the multi-stage system was 0.2 - 0.4 ㎜ thicker than the conventional one. Root weights of lightweight bed-soil were similar to those of conventional cultivation. The yield of ginseng seedlings in the 1 st, 2 nd and 3 rd stage was 721.3 g, 692.0 g, and 394.7 g/1.62 ㎡ respectively. Conclusion : In the production of ginseng seedling using multi-stage facilities, the commercial bed-soil was better than the conventional bed-soil (light, workability). The differences in yields in the multi-stage facilities can be overcome if the growth management such as moisture management is more systematic. If we develop the technology to reuse the bed-soil after harvesting the ginseng seedling, it will be economical and able to supply to farmers.
        151.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        This Research was the standardization of nutrient sources by reviewing the possibility of cultivation and analysis of imported nutrient sources used in Pleurotus ostreatus culture. As a first result, the concentration of heavy metals was not detected or trace, and the total nitrogen content of cotton seed pomace was 6.22% in Australia, which was higher than that of Chinese or USA. As a second result of physical properties of nutrient sources, the water holding capacity of beet pulp from Egypt was higher with increasing pressure. The volume water content of US was highest at 400hpa and 500hpa in case of cottonseed meal. Third, the content of total nitrogen was the highest at pH 5.51 and the total nitrogen content was the highest at 2.45, and the C/N ratio was the highest at 28.18. Last result shows that first germination day, yield and biological effciency of all treatments were not significant differnet except T2. These results shows that australian cootton was inappropriate to Pleurotus ostreatus culture. Nevertheless, the safety and standardization of the Pleurotus ostreatus culture medium should be assured by reviewing the media low material importing season, mushroom yield and nutrient sources.
        152.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        증가하는 유방암을 발견하고 치료하기 위한 기본검사인 유방 촬영은, 대부분 여성에게 암이나, 방사선 피폭으로 인한 불안을 주게 된다. 게다가 두려운 압박 통증을 주게 되므로, 불안과 통증의 정도를 파악하 고, 통증을 완화할 방법을 실험 연구하였다. 임상 경험을 바탕으로 변형된 촬영 방법과 기본 방식의 촬영 방법을 각각 비교 분석하여, 그 효과를 평가하는데 목적이 있다. 연구대상은 2017년 2월부터 3월까지 서울 대병원운영 서울특별시보라매병원에 유방촬영을 목적으로 내원한, 30대부터 60대 이상까지의 여성 160명 이었다. 변형된 유방촬영 방법 80명과, 기존의 유방촬영 방법 80명의 두 그룹으로 나누어 검사하고, 순차적 으로 연구대상자 모르게 각각에게 설명하고 설문지를 작성하게 하였다. 연구방법은 첫 번째는 자동페달을 4회 이상 나누어 압박하고, 수동압박을 동시에 이용하며, 자세히 설명하는 태도로 시행하는 변형 방법이다. 두 번째는 기본 방법인 자동 페달 압박 방식만 사용하며, 압박 횟수를 1-3회 이내로 제한하고, 단순히 설명 하는 태도로 촬영하였다. 통증 분포의 평균을 살펴보면 실험군(변형촬영방법)은 2.49이고, 대조군(기본촬영 방법)은 평균 4.86으로 48.8%로 통증이 감소하는 효과를 나타냈다. 이처럼 변형된 방법으로 촬영한 경우, 실험군이 대조군보다 통증 지수가 낮게 나타났으며, 그 정도는 통계적으로 유의한 결과를 보여주었다 (p <0.001).
        157.
        2017.05 KCI 등재 서비스 종료(열람 제한)
        This paper proposes an integrated positioning system to localize a moving object in the shadow-area that exists in the water tank. The new water tank for underwater robots is constructed to evaluate the navigation performance of underwater vehicles. Several sensors are integrated in the water tank to provide the position information of the underwater vehicles. However there are some areas where the vehicle localization becomes very poor since the very limited sensors such as sonar and depth sensors are effective in underwater environment. Also there are many disturbances at sonar data. To reduce these disturbances, an extended Kalman filter has been adopted in this research. To localize the underwater vehicles under the hostile situations, a SVR (Support Vector Regression) has been systematically applied for estimating the position stochastically. To demonstrate the performance of the proposed algorithm (an extended Kalman filter + SVR analysis), a new UI (User Interface) has been developed.
        158.
        2017.05 서비스 종료(열람 제한)
        천연자원 고갈 및 훼손에 따른 문제 해결을 위하여 최근 「건설폐기물의 재활용촉진에 관한 법률」 제38조제3항에 따른 ‘순환골재의무사용건설공사의 순환골재 사용용도 및 의무사용량 등에 관한 고시’ (환경부 고시 제2009-138호, 국토해양부 고시 제2009-713호, 2009.8.25)에 따라 1㎞ 이상의 도로를 건설할 경우 반드시 재생아스콘을 사용해야한다. 환경부는 공공기관이 발주하는 건설공사에 사용하는 의무사용 비율을 현재 15%에서 40%로 높여갈 계획에 있다. 이러한 정부의 정책에도 불구하고 재생아스콘의 사용 실적이 저조한 이유에는 그 기능성 및 가격경쟁력의 문제가 크다고 할 수 있고 재생아스콘의 사용 공법에는 포장 시 가열의 유무에 따라 가열재생아스콘과 상온순환아스콘으로 구분되어 진다. 환경부하저감과 자원절약의 의미로 시행되는 재생아스콘은 가열시 발생되는 이산화탄소 및 에너지 소비측면에서 적합하지 않으며, 특히 가격 경쟁성에서 시장성이 떨어진다. 따라서 상온순환아스콘의 확대보급을 위한 기술개발이 필요하며 이에 본 연구는 최근 저탄소 녹색생산 및 경제성 향상을 위한 자원재활용과 고부가성을 요구하는 시멘트 업계의 동향을 고려하여 무기계 순환자원의 확보와 개발을 우선하였다. 이에 본 연구는 노내 탈황을 하는 유동층 보일러를 운전하는 발전소에서 석탄 + 폐타이어고형연료 + 석회석을 혼합 연소하고 남은 산업부산물과 고로슬래그 미분말 및 탈황석고 등의 자원을 재활용하여 시멘트를 전혀 사용하지 않고 고온의 소성과정 없이 상온에서 제조가 가능한 상온순환아스콘 채움재 개발과 그 특성평가를 진행하였다. 본 연구는 KS L 5105에 명시된 시험방법으로 실험을 진행하였으며 각각의 배합에 따른 유동성, 압축강도, 기타 물성 등을 시험하였으며 석회석의 탈탄산 과정 및 탈황반응으로 석회 및 석고 성분인 CaO 성분과 CaSO4 등이 다량 함유되어 있는 폐타이어고형연료 연소재를 혼입한 채움재의 물성을 확인하였다.
        159.
        2017.02 KCI 등재 서비스 종료(열람 제한)
        본 연구는 2000년부터 최근 2016년 6월까지 월별 시계열 자료를 이용하여 대표적 글로벌 운임지수인 발틱 건화물지수(Baltic Dry-bulk Index 이하 BDI)와 중국의 컨테이너 운임지수(China Container Freight Index 이하 CCFI) 간의 동조성을 분석한다. 경기변동모형 의 불안정성을 반영한 Engle-Granger 2단계 공적분 검정결과는 두 시장간 동조성이 존재하지 않는 것으로 나타났으나, 인과성 검정결과는 전세계 물동량의 상당부분을 차지하는 중국의 해운시황이 글로벌 운임시장에 통계적으로 유의한 영향이 존재하는 것으로 드러났다. 이러한 실증분석결과는 해운시황 예측에 중국의 CCFI지수를 어떻게 활용하는 것이 적합한가에 대한 답을 제시한다. 즉, 실무에서 중국의 운임지수 CCFI를 글로벌 운임지수 BDI를 대신하여 분석하는 것은 적합하지 않으며, BDI 예측모형에 CCFI를 포함하는 것이 적절함을 의미한다. 이상 의 실증분석 결과는 산업간 동조성 분석을 해운산업의 경기변동에 적용한 사례로 향후 불안정한 글로벌 시황 예측에 중국의 경기변동 상황을 어떻게 고려하는 것이 적절한가를 제시한다.
        160.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        This experiment was conducted to assess changes to the chemical properties of soil and applicability in a case of rice cultivation with organic fertilizers. The investigator applied organic fertilizers to rice cultivation for five years to examine changes to the chemical properties of soil and found that the experiment group of organic fertilizers made an ongoing increase in pH, organism content, and available phosphate content annually compared with the control group with no big differences according to the amounts of organic fertilizers used. As for the yield components, there were no statistical differences in the number of spikelets and grain filling rate between the experiment group of organic fertilizers and the control group. The experiment group recorded a higher level in 1,000 seeds weight and yield than the control group. Experiment Group 4 recorded the highest level at 29.11 kg of 1,000 seeds weight. Experiment Groups 3 and 4, which used 222 kg and 267 kg per 10 a, respectively, recorded 576 kg and 572 kg of yield, respectively, which were 4.7% and 4.1% higher than 549 kg of control group, respectively. As for the quality of brown rice, there were no statistical differences in the head rice percentage between the control and experiment group, both of which were in the range of 83.2-85.7%. As for the protein content, Experiment Groups 3 and 4, both of which used a lot of organic fertilizers, were in the range of 6.9-7.1%, which was lower than 7.5% of control group. Those findings indicate that the long-term application of organic fertilizers can improve the chemical properties of soil and increase the yield more than the conventional method of fertilizer application. The findings also suggest that it will be effective to apply 222 kg of organic fertilizers or more per 10 a.