• 농업과학연구
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• 제43권3호
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• pp.432-440
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• 2016

The consumption of pre-treated vegetables (including fresh-cut vegetables) that are washed, peeled, and trimmed has been significantly increased because of their easy use for cooking. Vegetable cutting machines have been widely utilized for producing fresh-cut vegetables or agricultural products of different sizes; however, the design standard is not established for specific types of agricultural products. Therefore, this study was conducted to determine mechanical properties (compressive and shear forces) of targeted agricultural products (radish, carrot, squash, cucumber, shiitake mushroom, and sweet potato) for developing a multipurpose vegetable cutting machine. According to ASAE standard (s368.3), compressive and shear forces of targeted agricultural products were measured by using a custom built UTM (universal testing machine). Shape type of samples and speed ranges (5 - 15 mm/min) of loading rate on bioyield and shear points varied depending on the targeted agricultural product. The range of averaged bioyield points of targeted agricultural products were between 7.89 and 146.98 N. On the other hand, their averaged shear points ranged from 22.50 to 53.47 N. Results clearly showed that the bioyield and shear points of targeted agricultural products were thoroughly affected by their components. As measuring compressive and shear forces of a variety of agricultural products, it will be feasible to calculate blade cutting force for designing multipurpose vegetable cutting machine.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1419-1427
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• 2007

본 논문에서는 영상의 윤곽선을 검출하여 배경 블록과 윤곽선 블록으로 분류하고 윤곽선 맵을 작성하여, 윤곽선 블록에 대해서는 다시 DCT의 AC 계수를 사용하여 16개로 세분화한 후, 다중 면 사이드 매치 유한상태 벡터양자화를 수행하는 알고리듬을 제안한다. 윤곽선 맵의 정보에 따라 각각 주 부호책으로부터 상태 부호책을 작성하며, 현재 블록의 B면 또는 3면에 대해 사이드 매치 계산을 수행한다. 전송 비트 수를 줄이기 위해 먼저 부호화되는 블록들 중 배경 블록에 한하여 주 부호책으로 부호화 할 것인지를 결정한다. 또한 복호화기로 전송하는 부호단어 인덱스의 할당 비트를 줄이기 위해서 가변 길이 부호화를 수행한다. Zelda, Lenna, Bridge, Peppers 영상에 대하여 본 알고리듬으로 영상을 부호화했을 때 SMVQ와 TSMVQ 알고리듬보다 더 좋은 영상의 화질을 얻을 수 있었다.

• 국제강구조저널
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• 제18권4호
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• pp.1336-1349
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• 2018

Generally, a precast prestressed concrete (PSC) beam is used as girders for short-to-medium span (less than 30 m) bridges due to the advantages of simple design and construction, reduction of construction budget, maintenance convenience. In order to increase the span length beyond 50 m of precast PSC girder, PSC hollow box girder with unbonded prestressed H-type steel beam placed at the compressive region is proposed. The unbonded compressive prestressing in the H-type steel beams in the girder is made to recover plastic deflection of PSC girder when the pre-stressing is released. Also, the H-steel beams allow minimization of depth-to-length ratio of the girder by reducing the compressive region of the cross-section, thereby reducing the weight of the girder. A quasi-static 3-point bending test with 4 different loading steps is performed to verify safety and plastic deflection recovery of the girder. The experimental results showed that the maximum applied load exceeded the maximum design load and most of the plastic deflection was recovered when the compressive prestressing of H-type steel beams is released. Also using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and restoration difficulty and cost of PSC girders should be significantly reduced. The study result and analysis are discussed in detail in the paper.

• Computers and Concrete
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• 제27권4호
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• pp.333-341
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• 2021

Steel slag, an industrial reject from the steel rolling process, has been identified as one of the suitable, environmentally friendly materials for concrete production. Given that the coarse aggregate portion represents about 70% of concrete constituents, other economic approaches have been found in the use of alternative materials such as steel slag in concrete. Unfortunately, a standard framework for its application is still lacking. Therefore, this study proposed functional model equations for the determination of strength properties (compression and splitting tensile) of steel slag aggregate concrete (SSAC), using gene expression programming (GEP). The study, in the experimental phase, utilized steel slag as a partial replacement of crushed rock, in steps 20%, 40%, 60%, 80%, and 100%, respectively. The predictor variables included in the analysis were cement, sand, granite, steel slag, water/cement ratio, and curing regime (age). For the model development, 60-75% of the dataset was used as the training set, while the remaining data was used for testing the model. Empirical results illustrate that steel aggregate could be used up to 100% replacement of conventional aggregate, while also yielding comparable results as the latter. The GEP-based functional relations were tested statistically. The minimum absolute percentage error (MAPE), and root mean square error (RMSE) for compressive strength are 6.9 and 1.4, and 12.52 and 0.91 for the train and test datasets, respectively. With the consistency of both the training and testing datasets, the model has shown a strong capacity to predict the strength properties of SSAC. The results showed that the proposed model equations are reliably suitable for estimating SSAC strength properties. The GEP-based formula is relatively simple and useful for pre-design applications.

• 한국지반공학회논문집
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• 제36권12호
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• pp.117-124
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• 2020

본 연구는 온도에 따른 점성토의 전단 변형의 특성의 모사에 초점을 맞춘다. 일반적으로 온도가 상승할수록 정규압밀선은 간극비와 평균유효응력의 평면에서 하향 이동한다. 하지만 한계상태선은 온도변화에 따라 정규압밀선만큼 이동하지는 않는다. 따라서, 온도가 증가할수록, 한계상태 평균유효응력과 선행압밀 평균유효응력의 차이는 감소한다. 이를 반영하기 위해, 본 연구에서는 한계상태 평균유효응력을 기준으로 두 부분으로 나뉘어진 경계면을 적용하였다. 또한 Bangkok 점성토에 대해서 경계면을 구축하고, 비배수 삼축압축시험에 대해서 요소해석을 실시하였다. 요소해석 결과, 제안된 모델은 복잡한 강성 혹은 발달 법칙 없이 실험 데이터와 유사한 점성토의 온도에 따른 역학적 거동을 잘 모사하였다.

• PNF and Movement
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• 제10권1호
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• pp.61-70
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• 2012

Purpose : The purpose of this study was to investigate thigh muscle-bone CSA and leg strength during low-intensity exercise program with leg blood flow restriction by external compression to reduce muscle outflow. Methods : Eighteen health students gave informed written consent to participate in this investigation. An occlusion cuff was attached to the proximal end of the leg so that blood flow was reduced during the training. The training was conducted one times a day, three times a week, for 8 weeks using one sets of 30 minutes. The training program performed to squat with standing, lunge with standing and heel raise with one leg standing. Measurements of thigh muscle-bone CSA(cross-sectional area) and leg strength were evaluated pre and post-training. Statistical evaluation of these data was accomplished utilizing a paired t-test by SPSS 12.0 program for windows. Significance level was set at p <.05. Results : All data are reported as means and standard deviations(SD) for all variables. The result of the study is followed; After the training, muscle-bone CSA, gluteus maximus m, quadriceps m, hamstring m of both legs were significantly improved but not calf muscle(p<.05). There was no significant difference of change quantity between muscle-bone CSA and leg strength in Lt. and Rt. side. But the variation in leg muscle strength of Rt. leg(dominant) was much more increased than Lt. leg(non-dominant) after 8 weeks training. Conclusion : Low-intensity training with leg blood flow restriction offers a potentially useful method for improving leg muscle strength.

• 한국응급구조학회지
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• 제25권1호
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• pp.223-234
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• 2021

Purpose: The purpose of the study is to check up the status of 119 emergency control centers usage. Therefore, the status of use of 119 emergency control centers and the incidence of pre-hospital cardiac arrest patients were investigated. Methods: The emergency activity daily reports and first aid diaries of 119 emergency control centers from January to December 2018 were reviewed. For more accurate status analysis, Among the first aid guidance received in the emergency rescue standard system, the cardiopulmonary resuscitation guide log was reviewed. Results: In 2018, the total usage of the 119 emergency control centers was 1,358,356 calls, hospital guidance werethe most commom (n=629,676, 46.4%), followed by first aid (n=428,027, 31.5%), disease consultation (n=170,238, 12.5%), medical oversight (n=111,188, 8.2%), and interhospital transfer (n=5,052, 0.4%). Regarding the user number per 1,000 persons, Jeju was the greatest at 48.0, whereas Changwon was the lowest at 13.0. A total number of dispatcher-assisted cardiopulmonary resuscitation was 12.181. The time from report to chest compression were 156.2±80.8 seconds for those with previous cardiopulmonary resuscitation training and 168.0±79.3 seconds for those without such training (p<.05). Conclusion: The ratio of first aid instructions, including dispatcher-assisted cardiopulmonary resuscitation, among total usage of the 119 emergency control centers increased. Therefore, additional efforts are required to improve the quality and expertise of information provided through the 119 emergency control centers.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.677-692
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• 2021

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.399-415
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• 2023

This paper presents the experimental and numerical evaluations on the circular SFRC columns reinforced GFRP rebars under the axial compressive loading. The test programs were designed to inquire and compare the effects of different parameters on the columns' structural behavior by performing experiments and finite element modeling. The research variables were conventional concrete (CC), fiber concrete (FC), types of longitudinal steel/GFRP rebars, and different configurations of lateral rebars. A total of 16 specimens were manufactured and categorized into four groups based on different rebar-concrete arrangements including GRCC, GRFC, SRCC, and SRFC. Adding steel fibers (SFs) into the concrete, it was essential to modify the concrete damage plastic (CDP) model for FC columns presented in the finite element method (FEM) using ABAQUS 6.14 software. Failure modes of the columns were similar and results of peak loads and corresponding deflections of compression columns showed a suitable agreement in tests and numerical analysis. The behavior of GFRP-RC and steel-RC columns was relatively linear in the pre-peak branch, up to 80-85% of their ultimate axial compressive loads. The axial compressive loads of GRCC and GRFC columns were averagely 80.5% and 83.6% of axial compressive loads of SRCC and SRFC columns. Also, DIs of GRCC and GRFC columns were 7.4% and 12.9% higher than those of SRCC and SRFC columns. Partially, using SFs compensated up to 3.1%, the reduction of the compressive strength of the GFRP-RC columns as compared with the steel-RC columns. The effective parameters on increasing the DIs of columns were higher volumetric ratios (up to 12%), using SFs into concrete (up to 6.6%), and spiral (up to 5.5%). The results depicted that GFRP-RC columns had higher DIs and lower peak loads compared with steel-RC columns.

• 한국인터넷방송통신학회논문지
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• 제22권6호
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• pp.107-112
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• 2022

드론과 같은 임베디드 시스템에서 데이터를 서버로 전송해 실시간 분석을 진행함에 있어진행하는 데 초분광 영상 전체를 저장, 전송, 분석하는 데 전력 소모와 시간이 많이 소요되어 어려움이 있다. 그래서 초분광 영상 데이터는 차원 축소 또는 압축 전처리를 통해 서버로 전송하게 된다. 분석에 필요한 밴드만 보내기 위해서는 피처 선택 기법을 사용하는데 이러한 알고리즘은 대게 효율은 높더라도 영상 크기에 따라 처리 시간이 매우 소요가 크다. 본 논문에서는 밴드선택 알고리즘의 시간적인 단점을 개선하여한 기댓값 기반의 알고리즘을 제안한다. 실험 결과 8GB 데이터의 40000*682 해상도 이미지 기준 평균 소요 시간인 24시간을 60~180초 내외로 감소시키고, 150개 밴드 중에 45개를 활용하여 7.6GB 램 사용을 2.3GB로 크게 감소시켰다. 시간은 크게 줄였음에도 픽셀 분류 성능은 기존과 유사하게 98% 이상의 분석 결과를 도출하였다.