CRS 압밀시험속도 산정에 관한 연구

김팔규,류권일,최명진,고영헌 충남대학교 공업교육연구소 2002 論文集 Vol.25 No.1

Even though STD test based on Terzaghi's 1-D consolidation theory is extensively used to estimate the consolidation constant of soft-clay, it takes too much time to perform the test in addition to the problem in estimation of C_v and preconsolidation pressure. To overcome these defects, several types of rapid consolidation test, e.g., Constant Rate of Strain Test (CRS) and Controlled Gradient (CG), are proposed. Because consolidation characteristics obtained from the results of CRS test depend on the rate of rate of strain, it is repuired to determine the variation rate on the basis of the physical and structural characteristic in a building site, and then perform the test. Several methods determining the rate of strain, e.g., ASTM standard, Smith and Wahls' equation in 1969 and Armour and Drnevich's equation in 1986, have been researched. However, the rules about consolidation rates described in ASTM consider only the summary of the rate rules as a trial and error and its criterion also depends only on LL value. In this thesis, the test rate and parameters related in addition to LL value considered on ASTM basis are esamined in many fidlds of view ane the corresponding rate criterion is proposed.

일정변형률 압밀시험에 있어서 속도기준과 물성인자와의 상관관계에 관한 연구

김팔규,류권일,최명진,고영헌 忠南大學校 産業技術硏究所 2002 산업기술연구논문집 Vol.17 No.2

Even though STD test based on Terzaghi's 1-D consolidation theory is extensively used to estimate the consolidation constant of soft-clay, it takes too much to perform the test in addition to the problem in estimation of C_v and preconsolidation pressure. To overcome these defects, several types of rapid consolidation test, e.g., constant rate of strain test (CRS) an controlled gradient (CG), are proposed. Because consolidation characteristics obtained from the results of CRS test depend on the rate of strain, it is required to determine the variation rate on the basis of the physical and structural characteristic in a building site, and then perform the test. Several methods determining the rate of strain, e.g., ASTM standard, Smith and Wahls' equation in 1969 and Armour and Drnevich's equation in 1986, have been researched. However, the rules about consolidation rates described in ASTM consider only summary of the rate rules as a trial and error an its criterion also depends only on LL value.

Pre-processing of load data of agricultural tractors during major field operations

Ryu, Myong-Jin,Kabir, Md. Shaha Nur,Choo, Youn-Kug,Chung, Sun-Ok,Kim, Yong-Joo,Ha, Jong-Kyou,Lee, Kyeong-Hwan Institute of Agricultural Science 2015 Korean Journal of Agricultural Science Vol.42 No.1

Development of highly efficient and energy-saving tractors has been one of the issues in agricultural machinery. For design of such tractors, measurement and analysis of load on major power transmission parts of the tractors are the most important pre-requisite tasks. Objective of this study was to perform pre-processing procedures before effective analysis of load data of agricultural tractors (30, 75, and 82 kW) during major field operations such as plow tillage, rotary tillage, baling, bale wrapping, and to select the suitable pre-processing method for the analysis. A load measurement systems, equipped in the tractors, were consisted of strain-gauge, encoder, hydraulic pressure, and radar speed sensors to measure torque and rotational speed levels of transmission input shaft, PTO shaft, and driving axle shafts, pressure of the hydraulic inlet line, and travel speed, respectively. The entire sensor data were collected at a 200-Hz rate. Plow tillage, rotary tillage, baling, wrapping, and loader operations were selected as major field operations of agricultural tractors. Same or different farm works and driving levels were set differently for each of the load measuring experiment. Before load data analysis, pre-processing procedures such as outlier removal, low-pass filtering, and data division were performed. Data beyond the scope of the measuring range of the sensors and the operating range of the power transmission parts were removed. Considering engine and PTO rotational speeds, frequency components greater than 90, 60, and 60 Hz cut off frequencies were low-pass filtered for plow tillage, rotary tillage, and baler operations, respectively. Measured load data were divided into five parts: driving, working, implement up, implement down, and turning. Results of the study would provide useful information for load characteristics of tractors on major field operations.

Orlginal Article : Agri-environmental System Engineering and Energy ; Spatial, Vertical, and Temporal Variability of Ambient Environments in Strawberry and Tomato Greenhouses in Winter

( Myong Jin Ryu ),( Dong Ki Ryu ),( Sun Okk Chung ),( Yun Kun Hur ),( Seung Oh Hur ),( Soon Jung Hong ),( Je Hoon Sung ),( Hak Hun Kim ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.1

Purpose : In protected crop production facilities such as greenhouse and plant factory, farmers should be present and/or visit frequently to the production site for maintaining optimum environmental conditions and better production, which is time and labor consuming. Monitoring of environmental condition is highly important for optimum control of the conditions, and the condition is not uniform within the facility. Objectives of the paper were to investigate spatial and vertical variability in ambient environmental variables and to provide useful information for sensing and control of the environments. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2). Selected ambient environmental variables for experiment in greenhouse 1 were air temperature and humidity, and in greenhouse 2, they were air temperature, humidity, PPFD (Photosynthetic Photon Flux Density), andCO2 concentration. Results: Considerable spatial, vertical, and temporal variability of the ambient environments were observed. In greenhouse 1, overall temperature increased from 12:00 to 14:00 and increased after that, while RH increased continuously during the experiments. Differences between the maximum and minimum temperature and RH values were greater when one of the side windows were open than those when both of the windows were closed. The location and height of the maximum and minimum measurements were also different. In greenhouse 2, differences between the maximum and minimum air temperatures at noon and sunset were greater when both windows were open. The maximum PPFD were observed at a 3-m height, close to the lighting source, and CO2 concentration in the crop growing regions. Conclusions: In this study, spatial, vertical, and temporal variability of ambient crop growing conditions in greenhouses was evaluated. And also the variability was affected by operation conditions such as window opening and heating. Results of the study would provide information for optimum monitoring and control of ambient greenhouse environments.

Spatial, Vertical, and Temporal Variability of Ambient Environments in Strawberry and Tomato Greenhouses in Winter

Ryu, Myong-Jin,Ryu, Dong-Ki,Chung, Sun-Ok,Hur, Yun-Kun,Hur, Seung-Oh,Hong, Soon-Jung,Sung, Je-Hoon,Kim, Hak-Hun Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.1

Purpose: In protected crop production facilities such as greenhouse and plant factory, farmers should be present and/or visit frequently to the production site for maintaining optimum environmental conditions and better production, which is time and labor consuming. Monitoring of environmental condition is highly important for optimum control of the conditions, and the condition is not uniform within the facility. Objectives of the paper were to investigate spatial and vertical variability in ambient environmental variables and to provide useful information for sensing and control of the environments. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2). Selected ambient environmental variables for experiment in greenhouse 1 were air temperature and humidity, and in greenhouse 2, they were air temperature, humidity, PPFD (Photosynthetic Photon Flux Density), and $CO_2$ concentration. Results: Considerable spatial, vertical, and temporal variability of the ambient environments were observed. In greenhouse 1, overall temperature increased from 12:00 to 14:00 and increased after that, while RH increased continuously during the experiments. Differences between the maximum and minimum temperature and RH values were greater when one of the side windows were open than those when both of the windows were closed. The location and height of the maximum and minimum measurements were also different. In greenhouse 2, differences between the maximum and minimum air temperatures at noon and sunset were greater when both windows were open. The maximum PPFD were observed at a 3-m height, close to the lighting source, and $CO_2$ concentration in the crop growing regions. Conclusions: In this study, spatial, vertical, and temporal variability of ambient crop growing conditions in greenhouses was evaluated. And also the variability was affected by operation conditions such as window opening and heating. Results of the study would provide information for optimum monitoring and control of ambient greenhouse environments.

Pre-processing of load data of agricultural tractors during major field operations

Myong-Jin Ryu,Md. Shaha Nur Kabir,Youn-Kug Choo,Sun-Ok Chung,Yong-Joo Kim,Jong-Kyou Ha,Kyeong-Hwan Lee 충남대학교 농업과학연구소 2015 농업과학연구 Vol.42 No.1

Development of highly efficient and energy-saving tractors has been one of the issues in agricultural machinery. For design of such tractors, measurement and analysis of load on major power transmission parts of the tractors are the most important pre-requisite tasks. Objective of this study was to perform pre-processing procedures before effective analysis of load data of agricultural tractors (30, 75, and 82 kW) during major field operations such as plow tillage, rotary tillage, baling, bale wrapping, and to select the suitable pre-processing method for the analysis. A load measurement systems, equipped in the tractors, were consisted of strain-gauge, encoder, hydraulic pressure, and radar speed sensors to measure torque and rotational speed levels of transmission input shaft, PTO shaft, and driving axle shafts, pressure of the hydraulic inlet line, and travel speed, respectively. The entire sensor data were collected at a 200-Hz rate. Plow tillage, rotary tillage, baling, wrapping, and loader operations were selected as major field operations of agricultural tractors. Same or different farm works and driving levels were set differently for each of the load measuring experiment. Before load data analysis, pre-processing procedures such as outlier removal, low-pass filtering, and data division were performed. Data beyond the scope of the measuring range of the sensors and the operating range of the power transmission parts were removed. Considering engine and PTO rotational speeds, frequency components greater than 90, 60, and 60 Hz cut off frequencies were low-pass filtered for plow tillage, rotary tillage, and baler operations, respectively. Measured load data were divided into five parts: driving, working, implement up, implement down, and turning. Results of the study would provide useful information for load characteristics of tractors on major field operations.

FFT analysis of load data during field operations using a 75-kW agricultural tractor

Ryu, Myong-Jin,Chung, Sun-Ok,Kim, Yong-Joo,Lee, Dae-Hyun,Choi, Chang-Hyun,Lee, Kyeong-Hwan Institute of Agricultural Science 2013 Korean Journal of Agricultural Science Vol.40 No.1

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

FFT analysis of load data during field operations using a 75-kW agricultural tractor

Myong-Jin Ryu,Sun-Ok Chung,Yong-Joo Kim,Dae-Hyun Lee,Chang-Hyun Choi,Kyeong-Hwan Lee 충남대학교 농업과학연구소 2013 농업과학연구 Vol.40 No.1

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

제1발표장 : 노외기계시스템 분야 ; 모워 트랙터 자율주행 경로 생성을 위한 관행 작업 경로 분석

류명진 ( Myong Jin Ryu ),조명진 ( Myeong Jin Cho ),송명장 ( Ming Zhang Song ),정선옥 ( Sun Ok Chung ),이경환 ( Kyeong Hwan Lee ),유승화 ( Seung Hwa Yu ),김용주 ( Yong Joo Kim ) 한국농업기계학회 2013 한국농업기계학회 학술발표논문집 Vol.18 No.2

제3발표장 : 뇌외기계시스템 분야 ; 농작업별 트랙터 부하데이터 전처리 (1) -이상치 제거-

류명진 ( Myong Jin Ryu ),추연국 ( Youn Kug Choo ),정선옥 ( Sun Ok Chung ),김용주 ( Yong Joo Kim ),이대현 ( Dae Hyung Lee ),최창현 ( Chang Hyun Cho ),이경환 ( Kyeong Hwan Lee ) 한국농업기계학회 2013 한국농업기계학회 학술발표논문집 Vol.18 No.1