This paper presents about design efforts of a human-sized quadruped robot leg for high energy efficiency, and verifications. One of the representative index of the energy efficiency is the Cost of Transport (COT), but increased in the energy or work done is not calculated in COT. In this reason, the input to the output energy efficiency should be also considered as a very important term. By designing the robot with customized motor housing, small rotational inertia, and low gear ratio to reduce friction, high energy efficiency was achieved. Squatting motion of one leg was performed and simulation results were compared to the experimental results for validation. The developed 50 kg robot can lift the weight up to 200 kg, and during squatting, it showed high energy efficiency. The robot showed 71% input to output energy efficiency in positive work. Peak current during squatting only appears to be 0.3 A.

Background : Seed germination for Adenophora triphylla var. japonica Hara. is not good when grown in direct seeding. This experiment was conducted to identify seedling box suitable for seedling transplantation and cultivation to improve farm income and public health. Methods and Result : To investigate the effect on growth, sizes of seedling box used were as follows (width × length × height, in ㎝); 2.5 × 2.5 × 4 (custom), 4 × 4 × 4, 4.5 × 4.5 × 6, 5.0 × 5 × 9.6, 5 × 5 × 11.2, 5 × 5 × 17, and for sowing in narrow strips; 33.5 × 55 × 13, 33.5 × 49 × 23, 33.5 × 49 × 30. The weight of the ground part decreased as box height became lower, highest at 17 ㎝ tall (0.65 g) and lowest at 4 ㎝ (0.23 g). In terms of root length of the seedlings, the longest was 9.0 - 9.3 ㎝ at box height of 17 ㎝ and decreased as height decreased. Root weight increased as box height decreased, the highest at 4 ㎝. After the seedlings were planted, more than 90% survived in seedling box compared to the 50% rooting rate on sown in narrow strips where root net formation did not occur. During harvesting period, plant height was 15.8 - 17.5 ㎝ with a shoot diameter of 13.3 - 20.7 ㎜, leaf length of 5.6 - 7.9 ㎝ and leaf numbers 15.6 - 22.3. Moreover, leaf width was the widest at 8.6 ㎝ at 6 ㎝ box height while dry weight was the most at 6.7 g at 11.2 ㎝. Survival rate and growth characteristics of the ground part were lower in seedling box for sowing in narrow strips. For the underground characteristics, root number increased as box height decreased while dry weight increased as box height increased, with 1.7 - 3.5 and 6.2 - 6.8 less in seedling box for sowing in narrow strips, respectively. The yield in a 17 ㎝ high seedling box was 152 ㎏ per 10 a, 16% higher than conventional level, and decreased as box height decreased. Conclusion : These results suggest that the optimum seedling box height is 11.2 - 17 ㎝ to have lower root numbers and higher dry weight and yield.

This paper reports the absorption capacity of super-absorbent polymer (SAP) in water and cement pore solution. This was considered for the free water requirement for self-desiccation when the amount of internal water reduced. The physical state of particles selected from a super-absorbent polymer sample with a particle size distribution 150 μm (SAP-I) and less than 850 μm (SAP-II) monomers acrylic acid were tested at SAP 0.1g contents and time in minute 0.5, 1, 3, 5, 10, 30, and 60. The test was determined by using tea bag test method. As a result, the size of the polymers particles has a significant effect on the absorption kinetics of these polyacrylate-based polymers.

Void slab is a slab with hollow portions in the center of the slab which reduce a self weight of the slab. The flexural capacity of void slab is almost same with a normal slab, but the shear capacity is reduced according to the increasing of hollow portion. One of the solutions to improve shear capacity is using shear reinforcing bars. In this study, the shear capacity of one-way void slabs is evaluated according to an effective cross section and the capacity of shear reinforcing bars is discussed depending on integration method. As a result, it is shown that the shear capacity tends to be reduced from 0% to 34.5% of hollow rate and slightly increased from 34.5% to 40.0%. And the capacity of integrated shear reinforcing bars are better than the one without integrated shear reinforcing bars.

The specification of surface vegetation is essential for simulating actual evapotranspiration of water resources. The availability of land cover maps based on remotely collected data makes the specification of surface vegetation easier. The spatial resolution of hydrologic models rarely matches the spatial scales of the vegetation data needed, and remotely collected vegetation data often are upscaled up to conform to the hydrologic model scale. In this study, the effects of the grid scale of of surface vegetation on the results of actual evapotranspiration were examined. The results show that the coarser resolution causes larger error in relative terms and that a more realistic description of area-averaged vegetation nature and characteristics needs to be considered when calculating actual evapotranspiration.

As an interpretation of existing jamming effects, the main variables affecting the increase in stiffness due to jamming are known as system density, jamming density, pressure, and particulate temperature. The main variable, jamming density, is closely related to the distribution of particle size and contact properties such as particle shape and friction. However, the complexity of these variables makes it difficult to fully understand the mechanism of the jamming effect. In this paper, we focus on the jamming effects of particles that have more elastic properties than particles such as sand and coffee powder, which are commonly used as constituent particles of existing jamming, in order to reduce complicated factors such as temperature and concentrate on jamming effects based on elastic characteristics of particles. It was experimentally explored the possibility of increasing stiffness by mixing particles of different sizes rather than simply increasing the bending stiffness by controlling the particle size. Through simulations and experiments, we found a case where the stiffness of each particle size distribution is larger than the stiffness of each particle size.

One of the most frequently performed tasks in human-robot interaction (HRI), intelligent vehicles, and security systems is face related applications such as face recognition, facial expression recognition, driver state monitoring, and gaze estimation. In these applications, accurate head pose estimation is an important issue. However, conventional methods have been lacking in accuracy, robustness or processing speed in practical use. In this paper, we propose a novel method for estimating head pose with a monocular camera. The proposed algorithm is based on a deep neural network for multi-task learning using a small grayscale image. This network jointly detects multi-view faces and estimates head pose in hard environmental conditions such as illumination change and large pose change. The proposed framework quantitatively and qualitatively outperforms the state-of-the-art method with an average head pose mean error of less than 4.5° in real-time.

This study is an analytical research on the size effect of concrete flexural-compressive strength. The meso-scale finite element method was used to analyze various sizes of specimens. As a result of the analysis, the size effect that the flexural-compressive strength becomes smaller as the size of specimen becomes bigger is analytically confirmed.

조영제의 혈관외유출을 한번이라도 경험한 방사선사들은 혈관외유출의 발생에 대한 두려움으로 검사하 는 동안 정신적 고통을 수반하게 된다. 환자의 경우 심한 신체적, 정신적 고통과 의료진 및 의료에 대한 불 신을 갖게 되므로 미연에 예방할 수 있는 방안의 마련이 무엇보다 필요하다. 따라서 본 연구에서는 조영제 주입 시 압력인 PSI를 낮추어 혈관외유출을 예방하고자 하며 그 방안으로 자동주입기와 환자의 정맥주사 바늘에 연결되는 Y자 형태의 연결관(connecting tube)의 직경에 따른 조영제 주입 시 PSI의 변화를 비교 분 석하고자 하였다. Y형태의 연결관 직경이 약 2 mm 정도인 A제품의 경우 전체 평균 연령의 PSI는 98.5, 표 준편차 9.72로 나타났다. 연결관 직경 약 3 mm 정도인 B제품의 경우 전체 연령의 평균 PSI는 62.0, 표준편 차 8.59로 나타났다. 이것은 직경이 더 넓은 B제품의 경우 A제품과 비교했을 때 평균압력이 37.05% 감소한 결과이다.

This study was aimed to investigate the effect of aggregate size on the tensile behavior of highly ductile fiber-reinforced cementitious composites. Partial applying 5.6mm coarse aggregate instead of micro silica sand was considered. It was revealed that the fiber-reinforced cementitous composites with 5.6 mm coarse aggregate as well as micro silica sand still showed enough tensile strain capacity more than 5% and limited crack width less than 150 ㎛.

This study was aimed to investigate the effect of aggregate size on the tensile behavior of highly ductile fiber-reinforced cementitious composites. Partial applying 5.6mm coarse aggregate instead of micro silica sand was considered. It was revealed that the fiber-reinforced cementitous composites with 5.6 mm coarse aggregate as well as micro silica sand still showed enough tensile strain capacity more than 5% and limited crack width less than 150 ㎛.

To understand the changes in physical parameters and phytoplankton size structure caused by tides, a fixed station in the Youngsan River estuary was monitored at 2-h intervals, on April 28, 2012 and August 12, 2012. No clear relationship was observed between the temperature and salinity changes and tidal levels in April. However, in August, temperature decreased during the ebb tide and increased during the flood tide, while salinity showed the opposite trend. In addition, there was no specific change in the phytoplankton biomass corresponding to tidal levels in April. In August, the total chlorophyll a and the biomass of net phytoplankton (>20μm ) increased almost 20 times during the ebb tide and decreased during the flood tide. The biomass of nanophytoplankton (<20μm ) showed a similar variation in response to tidal level changes. In April, the relationship between percent contributions of phytoplankton size structure and tidal levels was not clear. In August, the net phytoplankton was dominant in the early stage and nanophytoplankton was dominant in the later stage, while contribution of nanophytoplankton and net phytoplankton increased at high tide and low tide, respectively. Therefore, in April, other factors such as freshwater discharge were more important than the tide, whereas in August, when no freshwater discharge was recorded, the changes in semidiurnal tides influenced the physical parameters and phytoplankton dynamics. These results could contribute to the understanding of phytoplankton dynamics in the Youngsan River estuary.

This study is an experimental program developed to estimate the effect of size on the shear performance of reinforced concrete (RC) beams with stirrups made from recycled coarse aggregates (RCA). The test was conducted on eight RC beams with shear reinforcement, and the main variables were section size and RCA replacement ratio (Rr = 0% or 30%). The tension reinforcement ratio (ρ = 0.012), shear span-to-depth ratio (a/d = 1.5), and width-to-depth ratio (h/b = 1.5) were fixed. Empirical test results, theoretical results, and code calculations were compared for each specimen. The results demonstrated that the empirical test results of each sample compared favorably with the theoretical calculations within a sufficient safety margin (1.32-2.61). Also, a comparison between RCA-RC beams with Rr = 30% and RC beams containing natural coarse aggregates (NCAs) showed that the two beams exhibited similar load-displacement curves and shear strengths. Consequently, RCA-RC beams made using a RCA replacement ratio of up to 30% do not cause safety or serviceability problems.

This study was aimed to investigate the effect of aggregate size on the tensile behavior of highly ductile fiber-reinforced cementitious composites. Partial applying 5.6mm coarse aggregate instead of micro silica sand was considered. It was revealed that the fiber-reinforced cementitous composites with 5.6 mm coarse aggregate as well as micro silica sand still showed enough tensile strain capacity more than 5% and limited crack width less than 150 ㎛.

본 연구에서는 LRB 받침을 갖는 플레이트 거더교를 해석 대상 교량으로 하고 편구배별 곡선반경과 사각을 해석변수로 하여 교량 받침의 반력에 미치는 영향을 평가하고자 하였다. 지진파로는 El-Centro 지진 기록과 인공지진파를 각각 교축방향과 교축직각방향으로 적용 하고 3D 해석을 수행하였다. 해석결과, 곡선교 내측과 예각부에서 부반력이 발생될 가능성이 높은 위치로 나타났으며, 또한, 교축 직각방향으 로 지진이 작용하였을 때가 또한 가능성이 높은 조건으로 해석되었다. 그 이외에도 직선교보다는 곡선교이면서 곡률반경이 작고 사각이 작을 수록 부반력의 발생 가능성이 높은 것으로 나타났다. 따라서 교량의 부반력 발생여부는 지진파의 종류 및 교량의 편구배, 곡선반경, 사각 등을 종합적으로 고려하여 검토하여야 할 것으로 판단된다.

본 연구에서는 히알루론산나트륨(sodium hyaluronate, HA)을 효소 분해하여 분자량 크기(1, 10, 50, 100, 660, 및 1500 kDa) 별로 제조한 뒤 콜라겐 합성 및 항염증 활성에 미치는 영향과 피부투과도를 조사하였 다. 이들 HA는 인간피부세포인 Hs68 세포에 세포독성을 나타내지 않았다. 콜라겐 생합성능은 1500 kDa, 50, kDa HA가 각각 59, 50%로 콜라겐 생합성 촉진능이 우수한 것으로 나타났다. 분자량 크기에 따른 HA의 피부투 과도를 측정한 결과 660 또는 1500 kDa의 HA은 2% 미만의 미미한 투과율을 보였으나, 저분자 HA (1, 10, 또는 50 kDa)은 시간이 지남에 따라 투과율이 증가하는 것을 확인하였다. 마우스 대식세포인 RAW 264.7 세포 에서 HA 분자량 크기에 따른 항염증 효과를 확인한 결과, 50 kDa HA가 농도 의존적으로 nitric oxide 및 tumor necrosis factor-α 합성을 저해하여 다른 분자량의 HA (1, 10, 및 100 kDa)에 비해 가장 큰 항염증 효능을 나타냈다. 현재까지 효소(hyaluronidase) 처리하여 제조된 다양한 크기의 분자량(1, 10, 50, 100, 660, 1500 kDa)의 HA 중 50 kDa HA가 collagen의 합성, 항염증 및 피부 흡수도에 대한 종합적인 평가를 한 사례 는 없었다. 따라서 이러한 연구결과는 50 kDa의 HA가 인간피부세포에서 콜라겐 합성을 증진시키고, 피부 투과 율을 높으며 피부 주름을 유발하는 염증반응을 억제함으로써 피부노화 및 주름 개선용 화장품소재로 개발될 수 있는 가능성을 보여준다.

Some researchers suggested that bolt slippage occurred in column-tree connection type. In this paper, bolt slippage was evaluated on different depth of beam. When the length of beam set 7,500 mm equally, three depth of beams was 600, 500, 400mm, respectively. Also, column size of all specimens was same, and panel zones was strongly reinforced to evaluate bolt slippage in beams. As a result of full-scale testing, the bolt slippage of all specimens was occurred within plastic rotation ± 2.0%. It was showed that the effect of bolt slippage on depth of beam was slight.