• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.2
• /
• pp.184-191
• /
• 2009

The common requirements of rough terrain mobile robots are long-term operation and high mobility in rough terrain to perform difficult tasks. In rough terrain, excessive wheel slip could cause an increase in the amount of dissipated energy at the contact point between the wheel and ground or, even more seriously, the robot could lose all mobility and become trapped. This paper proposes a traction control algorithm that can be independently implemented to each wheel without requiring extra sensors and devices compared with standard velocity control methods. The proposed traction algorithm is analogous to the stick-slip friction mechanism. The algorithm estimates the slippage of wheels by angular acceleration change, and controls the increase or decrease state of torque applied to wheels Simulations are performed to validate the algorithm. The proposed traction control algorithm yielded a 65.4% reduction of total slip distance and 70.6% reduction of power consumption compared with the standard velocity control method.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.806-807
• /
• 2011

This paper presents a new sensorless controller used with both the classical sliding mode observer(SMO) and the rate of current change in order to a reduced torque ripple for switched reluctance motor (SRM) sensorless drives. The new sensorless scheme consists of a sliding mode observer (SMO)-based position sensorless approach for high speeds along with a low-resolution discrete the rate of current change for low speeds and standstill. The new position estimation resets between the SMO and the low-resolution of current change according to the speed sign and the position error difference between the SMO and the low-resolution rate of current change. The simulation results show the robustness of this new high performance sensorless control approach with the hybrid sensorless control topology.

• Clinical and Experimental Reproductive Medicine
• /
• v.22 no.3
• /
• pp.287-291
• /
• 1995

Hemospermia is not an uncommon disease and may affect the sperm motility. But the research about sperm motility in hemospermia is rare. So we studied the change of sperm motility between control group and patients with hemospermia and also studied the change of sperm motility between patients with hemospermia and those whose hemospermia was improved, the change of sperm motility between control group and artificially induced hemospermia group. We observed that the sperm motility in patients with hemospermia was decreased than that of control group, and that, as hemospermia being better, sperm motility was improved. We also observed that sperm motility in artificially induced hemospermia was decreased. The results provide that hemospermia has an effect on decreasing hemospermia motility.

• The Journal of Internal Korean Medicine
• /
• v.22 no.2
• /
• pp.145-160
• /
• 2001

Objectives : The purpose of this investigation is to evaluate the effect of Geupoongjibo-dan Extracts on Reversible Forebrain Ischemia in Mongolian Gerbils. Methods : The change rate of water content in cerebral tissues, the numercal change of the CA1 pyramidal neuron in the hippocampus, the change of delayed neuronal death(necrosis apoptosis) through light microscopy, the reactivity change of glycoprotein in neuronal membrane and the ultrastructural change of pyramidal neuron through electron microscopy caused by dalayed neuronal death were investigated. Results : 1. The change rate of water content in the normal group showed 78.90% on the third day, and 79.12% on the seventh day after an attack of ischemia. The rate in the control group showed 82.25% and 85.13%, respectively. The rate in the sample group showed a significant decrease: 81.72% and 83.66%. 2. Light microscopy revealed that the cells, continuous and systematic forms in the pyramidal cells of hippocampus, changed into discontinuous and unsystematic forms in the normal group when compared with the control group. The cells were less damaged in the sample group. 3. The mean of the numerical change of the CA1 pyramidal neurons in the hippocampus was 104 in the normal group. The mean of the control group was decreased to 27. The mean of the sample group was 44. 4. TUNEL staining examination reveals that the whole part of the hippocampus of the normal group had negative reactivity. As far as CA1 pyramidal neurons in the hippocampus, the control group had positive reactivity. The sample group was more positive than the control group. 5. Electron microscopy reveals that the ischemic injury of the control group had both necrotic and apoptotic morphology. The sample group was less necrotic, and more apoptotic morphology than the control group. 6. Lectin histochemisrical examination reveals that the normal group had positive reactivity to PNA and SBA in interneuron, and weak positive reactivity to WGA Con A LCA in intercelluar space. The reactivity to PNA and WGA decreased in the control group. The reactivity to PNA and WGA tended to increase in the sample group. Conclusions : The data shows that the effect of Geupoongjibo-dan Extracts on Reversible Forebrain Ischemia in MG is a significant result.

• Korean Journal of Environmental Agriculture
• /
• v.42 no.1
• /
• pp.63-70
• /
• 2023

Golden apple snails (Pomacea canaliculat) (GAS) are widely used for weed control in rice cultivation. However, concerns on the ecological risk of invasive GAS species are increasing. This study aimed to evaluate the overall impacts of GAS on weed control, abundance of aquatic animals and insects, and rice yield, in comparison with that from other biocontrol agents such as loach (Misgurnus mizolepis) and catfish (Silurus asotus), which are alternatives for biological weed control in rice paddy cultivation. Field experiments included five treatments; control, herbicide, GAS, loach, and catfish. During the rice growth, weed appearance and biological abundance were monitored, and at harvest, the rice yield was determined. Weed control efficiency was the highest for GAS treatment (100%), followed by that for herbicide (95.8%), loach (57.5%), and catfish treatments (31.7%). Insect abundance was considerably decreased in GAS treatment due to heavy weed removal, which affects the habitat of aquatic animals and insects. The amount of rice yield (unit: kg 10 a^-1) was in the order of GAS (798.9) > loach (708.1) = herbicide (700.7) > catfish (629.4) > control (496.0). Therefore, considering the weed control efficiency, biological abudance, and rice yield, loach could be a potential alternative for biological weed control in organic rice farming. However, the activity of the biocontrol agents are susceptible to environmental conditions; therefore, further studies under different conditions are essential to confirm these findings.

• Korean Journal of Community Nutrition
• /
• v.12 no.4
• /
• pp.477-488
• /
• 2007

Prevalence of an obese population has been increasing in Korea. Obesity is considered a major risk factor for chronic degenerative diseases. Specifically, prevalence of obesity is prominent for adult woman in Korea. In many weight control programs, weight change did not often show any beneficial effects for health. These facts discourage people in the program. Thus in this study, the anthropometry, blood pressure, serum biochemical indices and dietary habits were compared by percent body fat change for adult women to show the beneficial effects of the weight control program. Study subjects were 134. Measurements were done before and after the weight control program. Percent Body Fat (PBF) was measured by bioelectrical impedance analysis. Using PBF changes, subjects were grouped as I (more than 1% increase), M (${\pm}1%$ change), and D (more than 1% decrease). Data were analyzed using SPSS 12.0 program. Among the 134 participants, 13 increased their weight and 100 decreased. For PBF, 19 increased and 59 decreased. Statistical significant differences were shown for anthropometric assessments before and after for all weight, fat mass, percent body fat, waist-hip ratio and body mass index. I had increases, and D shows decreases. But the difference of D is large than M. Systolic and diastolic blood pressures decreased in all groups (p < 0.05). Fasting blood glucose decreased in all groups but were statistically significant only in D. Also triglyceride decreased in D (p < 0.05). Thus health conditions showed desirable changes in I < M < D in order. Dietary habit changes were desirable with only D. Weight, BMI and other indicators for obesity is not the real indicator for PBF. Recently it is easy to measure PBF. Thus, for weight control programs and to show benefits of the program, PBF is a good indicator for adult women in Korea.

• Journal of the Korean Society of Physical Medicine
• /
• v.11 no.4
• /
• pp.71-78
• /
• 2016

PURPOSE: The purpose of this study was to investigate which treadmill walking training mode is more effective strategy for improving pulmonary function of persons with chronic stroke. METHODS: Twenty-one chronic stroke patients were allocated and randomly to an experimental group (treadmill training with randomized speed control, n=11) and a control group (treadmill training without speed change, n=10). All participants received 30 minutes of neurodevelopmental treatment. In addition, the two groups performed treadmill training for 20 minutes each time with or without speed change. Speed change was applied 40%, 50%, 60%, 70% of Heart Rate Reserve. All the exercise programs lasted six weeks, with five times per week. Pulmonary function was assessed before and after exercise program by using forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and maximal voluntary ventilation (MVV). RESULTS: In the both groups, FEV1 was significantly increased after training (p<.05). Compared to the control group, the experimental group showed 11.9% larger amount of change (p<.05). In the experimental group, FVC and MVV were significantly increased after training (9.9%, 7.6%, respectively) (p<.05). But in the control group, there was no significant difference in the FVC and MVV after training. CONCLUSION: Treadmill training with randomized speed control will be a better positive rehabilitation program than treadmill training without speed change to improve pulmonary function in persons with chronic stroke.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.119-126
• /
• 2001

This paper analyzes problems related to total cost changes in private investment projects, and then proposes an improvement measure for the control of cost changes within the framework of the project management, contract, human resource, project communication, cost, and time management. From the viewpoint of contract management, the basis of cost change ought to be cleared up with standardization of related provisions in the concession agreement, and potentiality of change ought to be excluded with prescription of the private investor's leading role from the design phase. Regarding human resource management, this paper proposes a standard work flow granting much sovereign rights to private parts by putting restriction on work scopes of the entrusted authority of government, and transferring the rights of assignment, contract, and control about the responsible supervisor to the concessionaire. With regard to project communication management the notification of changes on drawings and technical documents ought to be automated and the realtime database ought to be established with DMIS (Drawings & Documents Management Information System). From the cost management point of view, this thesis integrates the control of cost-change-approved items and disapproved items to one cost breakdown system, and then harmonizes the actual progress with EVMS in time management.

• Korean Journal of Agricultural Science
• /
• v.44 no.2
• /
• pp.296-307
• /
• 2017

Globally, consumers' enormous and increasing appetite for meat is one of the biggest causes of climate change because livestock industry emits more greenhouse gas than transportation. The purpose of this study is to analyze consumer awareness about the impact of meat consumption on sustainability in response to climate change. Based on the theory of planned behavior, the attitudes, subjective norms, perceived behavioral control, prior knowledge, and risk perception variables were analyzed to evaluate the impact of climate change awareness over consumer behavior on meat consumption. Major findings are as follows: consumers were aware of climate change but has made few changes to their meat consumption. In addition, changes in meat consumption were found to be caused by health safety concerns, such as disease outbreaks. Significant variables related to meat consumption patterns associated to climate change impacts were household income, age, attitude, subjective norm, perceived behavioral control, and prior knowledge. These results suggest some implications for policy. There is a need for public relations and education to make the public aware of and better understanding of link between climate change and diet. Also, government should make efforts to raise awareness of mitigation of climate change such as comprehensive food labels which are identifying lesser impacts on climate and better dietary guideline instructions which would include coping with climate change.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2004.04a
• /
• pp.97-106
• /
• 2004

The paper making process itself is a typical nonlinear process with complicated dynamics. In the application of advanced control-methods especially for the grade change operations the nonlinear process is linearized to give suitable linear models to be used in the control strategies. However, the use of the linear model is limited within short range containing steady-state operating conditions for grade change operation. In this paper a bilinear model for the nonlinear grade change processes is presented. We can see that the dynamic behavior for grade change operations can be effective analyzed by using multivariable bilinear model.