• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.11
• /
• pp.952-960
• /
• 2018

Recently, lots of remote sensing satellite require agility to collect more images within the limited time frame. To satisfy this kind of mission requirement, high torque actuator such as CMG is an essential element. In this study, 5Nm class small CMG developed by KARI is introduced to implement for an agile small satellite design. One of the singularity escape CMG steering law, Designated Direction Escape (DDE) method, which is a sort of modified version of Singular Direction Avoidance (SDA) method is summarized for its application on the numerical simulation of agile attitude control system design result. The performance of DDE method is demonstrated properly by escaping well known elliptic internal singularity successfully. 5Nm class small CMG cluster in a pyramid type as well as a roof type configuration is utilized to perform the numerical simulation and to demonstrate its agility design result for a small satellite. Simulation result shows the properness of 5Nm small CMG to a small agile satellite system. Also, the simulation result provides some valuable information that is important to CMG hardware design and manufacturing.

• Journal of Korean Academy of Nursing
• /
• v.27 no.2
• /
• pp.329-340
• /
• 1997

Resourcefulness was analyzed by Walker and Avant's method to make a theoretical framework for nursing. Also, the appropriate Korean terminology was identified.“Resourcefulness”means the ability to use internal and external resources to eliminate or to control stress. '자원동원성' is chosen to be the most appropriate term to reflect the concept of resourcefulness. Upon the concept analysis, availability, controllability, confidence, and self-instruction were identified as the defining characteristics of resourcefulness. Contrary to other work, "availability" means the ability to use the social resources as well as the internal cognitive-behavioral resources. “Controllability” means the ability to delay or control immediate gratification of one's needs or to divert one's own mood in order to solve problem. "Confidence" is the self-efficacy belief in one's control ability. "Self-instruction" is the cognitive ability to instruct oneself positively. Resourcefulness is learned by active experience, vicarious experience, and formal or informal instruction, and it is cued in the presence of a stressful situation or a need for change. As a result of the use of resourcefulness, the target behavior performed immediately and ultimately improve the quality of life or adaptation. Therefore, it is necessary to develop the instrument including the defining attributes identified in this study. Also, it is necessary to simultaneously analyze the related concepts of self-efficacy, self-control, and self-regulation for appropriate use.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.306-308
• /
• 1999

Recently 2DOF control system has been widely recognized to be efficient. The major merit of 2DOF control is the independency between tracking performance and feedback performance. But the design of two parameters of 2DOF control system is not much considered about the relation between the identification and the design. In the field of robust control, the joint control, which can combine the identification with the design, is investigated. Then are apply the joint control to the design of 2DOF control system, and verify the effectiveness by some simulation.

• The Journal of Internal Korean Medicine
• /
• v.29 no.2
• /
• pp.375-384
• /
• 2008

Objective : This study was carried out to investigate the effects of oral administration of Hyeungbangjihwang-tang (HBJHT) on the liver cirrhosis of rats induced by Carbon tetrachloride for 10 weeks. Method : The histopathological changes were observed. The HBJHT extracts were daily dosed at 50, 100 and 200mg/kg for 12 weeks. Results : Severe hepatocellular necrosis and ballooning, hyperplasia of connective tissue, subdued reduction of hepatic lobule, and hyperplasia of bile duct in portal triad were dramatically decreased in the HBJHT-treated group compared to that of the Carbon tetrachloride-treated control group in histopathological observation. The diameter of hepatic lobules was significantly enlarged in the HBJHT-treated group compared to that of the Carbon tetrachloride-treated control group, and the amounts of connective tissue, degenerative cells and bile ducts were significantly and dose-dependently decreased. Conclusion : It is concluded that HBJHT has a significant recovering effect on the liver of rats induced by carbon tetrachloride.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.8
• /
• pp.579-584
• /
• 2016

When surgical instruments are tracked in an image-guided surgical navigation system, a stereo vision system with high accuracy is generally used, which is called optical tracker. However, this optical tracker has the disadvantage that a line-of-sight between the tracker and surgical instrument must be maintained. Therefore, to complement the disadvantage of optical tracking systems, an internal vision sensor is attached to a surgical instrument in this paper. Monitoring the target marker pattern attached on patient with this vision sensor, this surgical instrument is possible to be tracked even when the line-of-sight of the optical tracker is occluded. To verify the system's effectiveness, a series of basic experiments is carried out. Lastly, an integration experiment is conducted. The experimental results show that rotational error is bounded to max $1.32^{\circ}$ and mean $0.35^{\circ}$, and translation error is in max 1.72mm and mean 0.58mm. Finally, it is confirmed that the proposed tool tracking method using an internal vision sensor is useful and effective to overcome the occlusion problem of the optical tracker.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.1
• /
• pp.61-72
• /
• 2023

The increase in the rearing intensity of pigs has caused deterioration in the pig house's internal environment such as temperature, humidity, ammonia gas, and so on. Traditionally, the widely used method to control the internal environment was through the manipulation of the ventilation system. However, the conventional ventilation system had a limitation to control the internal environment, prevent livestock disease, save energy, and reduce odor emission. To overcome this problem, the air-recirculated ventilation system was suggested. This system has a semi-closed loop ventilation type. For designing this system, it was essential to evaluate the ventilation rates considering the pressure loss of ducts. Therefore, in this study, pressure loss calculation and experiment were conducted for the quantitative ventilation design of a semi-closed loop system. The results of the experiment showed that the inlet through which external air flows should always be opened. In addition, it was also found that for the optimum design of the semi-closed loop ventilation system, it was appropriate to install a damper or a backflow prevention device rather than a ventilation fan.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.2
• /
• pp.62-72
• /
• 2023

Objective: Although balance training has been used as an effective ankle injury rehabilitation program to restore neuromuscular deficits in patients with chronic ankle instability, it is not effectively used in terms of motor learning. Attentional focusing can be an effective method for improving ankle kinematics to prevent recurrent ankle injuries. This study aimed to 1) evaluate the effects of attentional focus, including internal and external focus, and 2) determine a more effective focusing method for patients with chronic ankle instability to learn balance tasks. Method: Twenty-four patients with chronic ankle instability were randomly assigned to three groups (external focus, internal focus, and no feedback) and underwent four weeks of progressive balance training. The three-dimensional ankle kinematics of each patient were measured before and after training as the main outcomes. Ensemble curve analysis, discrete point analysis, and post hoc pairwise comparisons were performed to identify interactions between groups and time. Results: The results showed that (1) the external focus group was more dorsiflexed and everted than the internal focus group; (2) the external focus group was more dorsiflexed than the no feedback group; and (3) the no feedback group was more dorsiflexed than the internal focus group. Conclusion: Because dorsiflexion and eversion are ankle motions that oppose the mechanism of lateral ankle sprain, using the external focus method during balance training may be more effective in modifying these motions, thereby reducing the risk of ankle sprain.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.4
• /
• pp.165-174
• /
• 2000

This paper presents the application of H$\infty$ control synthesis using LMI optimization method to power system stabilizer(PSS) design. Since power system is usually operated under circumstance of unmeasurable uncertainties and external disturbances, the improvement of small signal stability becomes one of the most important issue for securing system stability and preventing low frequency oscillation phenomena. The LMI optimized H$\infty$ PSS provides robust performance and guarantees the internal stability under these operating conditions. The global optimal H$\infty$ norm is found using LMI convex optimization method which is more systematic than standard two Riccati solution method. The design results are simulated for a case study. We verified that the LMI method shows the best performance characteristic smong standard Riccati method and conventional lead/lag method.

• Tuberculosis and Respiratory Diseases
• /
• v.42 no.5
• /
• pp.737-743
• /
• 1995

Background: Pneumonia is a frequent complication in patients undergoing mechanical ventilation, Quantitative culture of protected specimen brush(PSB) have shown satisfactory diagnostic accuracy for the diagnosis of ventilator-associated pneumonia. However PSB method is invasive, expensive, and require a bronchoscopic procedure. But endotracheal aspiration(EA) is simple and less expensive. The purpose of our study was to investigate the diagnosic value of EA quantitative cultures. Method: We studied 15 cases of ventilator-associated pneumonia(for >72h of mechanical ventilation) patients. Patients were divided into two diagnostic categories. Group I was the patients who were suspicious of clinical pneumonia, Group II was the patients for control. The obtained samples by EA and PSB were homogenized for quantitative culture with a calibrated loop method in all patients. Result: Using $10^3cfu/ml$, $10^5cfu/ml$ as threshold in quantitative culture of PSB, EA respectively, we found that EA quantitative cultures represented a relatively sentive(70%) and relatively specific (60%) method to diagnose the ventilator-associated pneumonia. Conclusion: Although EA quantitative cultures are less specific than PSB for diagnosing ventilator-associated pneumonia. EA quantitative cultures correlated with PSB quantitative culture in patients with clinical pneumonia and may be used to treat these patients when bronchoscopic procedures are not available.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.139-144
• /
• 1993

In this paper, a robust reduced order adaptive controller is proposed based on Internal Model Control(IMC) structure for stochastic linear stable systems. The concept of gain margin is utilized to make the adaptive IMC controller robust. We prove the stability of the proposed adaptive IMC system for stable plants under the assumption that upper bounds for system orders are known. Simulation results show that the proposed method has good performance and stability robustness.