• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.414-417
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• 1997

We propose a decentralized $H_{\infty}$ state estimation method in the multisensor state estimation problem. The proposed method bounds the maximum energy gain from unknown external disturbances to the estimation errors in the suboptimal case. And we formulate the decentralized state estimation method in the general case of different global and local models using alternative gain equation of the $H_{\infty}$ state estimator which can calculate global state estimates from the the linear combination of local state estimates. In addition, the proposed update equation between global and local Riccati solutions can reduce unnecessary calculation burden efficiently.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.150-160
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• 1995

The practical design and construction of a Stewart Platform-based unilateral universal hand-controller is presented. It is also presented that such a design concept could be implemented by developing a technical method of determining the forward kinematics of a Stewart Platform in real time. In this work, the forward kinematics of a Stewart Platform has been determined in real time using three additional displacement sensors which eliminate the computational burden of solving the forward kinematics described in nonlinear simultaneous equations. The workspace of the Stewart Platform via inverse kinematics has been analyzed numerically and used as a design guide for the determination of the mechanism dimensions such as the sizes of the upper and base platforms and the minimum and maximum lengths of the legs. The hardware of the hand-controller has been constructed and tested to demonstrate the feasibility of the design concept.

• ETRI Journal
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• v.37 no.4
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• pp.804-812
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• 2015

Energy harvesting (EH) technology in the field of wireless sensor networks (WSNs) is gaining increasing popularity through removing the burden of having to replace/recharge depleted energy sources by energy harvester devices. EH provides an alternative source of energy from the surrounding environment; therefore, by exploiting the EH process, WSNs can achieve a perpetual lifetime. In view of this, emphasis is being placed on the design of new medium access control (MAC) protocols that aim to maximize the lifetime of WSNs by using the maximum possible amount of harvested energy instead of saving any residual energy, given that the rate of energy harvested is greater than that which is consumed. Various MAC protocols with the objective of exploiting ambient energy have been proposed for energy-harvesting WSNs (EH-WSNs). In this paper, first, the fundamental properties of EH-WSN architecture are outlined. Then, several MAC protocols proposed for EH-WSNs are presented, describing their operating principles and underlying features. To give an insight into future research directions, open research issues (key ideas) with respect to design trade-offs are discussed at the end of this paper.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.153-157
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• 2002

Electricity living body formation operation appliance is using most imports until present. And, because electricity living body formation operation appliance is too expensive, it becomes burden to buy in small scale hospital. Also, problem that economical damage by income is added follows, Therefore, this treatise developed electricity living body formation operation appliance by home production, Ultra high frequency eruption circuit used LC circuit, and output frequency is possible to 8 [MHz], and output voltage amplified maximum 800 [V]. This operation appliance could display size of fixed current. This developed product could microscopic operation fewer than 1 [mm]. This development technology is considered by do metallic surface heat treatment, melting, welding, induction heating device and that can apply to domestic animals surgical operation and so on.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.127-132
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• 2002

Electricity living body formation operation appliance is using most imports until present. And, because electricity living body formation operation appliance is too expensive, it becomes burden to buy in small scale hospital. Also, problem that economical damage by income is added follows. Therefore, this treatise developed electricity living body formation operation appliance by home production. Ultra high frequency eruption circuit used LC circuit. and output frequency is possible to 8 [MHz], and output voltage amplified maximum 800 [V]. This operation appliance could display size of fixed current. This developed product could microscopic operation fewer than 1 [mm]. This development technology is considered by do metallic surface heat treatment, melting, welding, induction heating device and that can apply to domestic animals surgical operation and so on.

• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.46-57
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• 2006

It is well known that mathematical solutions for multi-agent planning problems are very difficult to obtain due to the complexity of mutual interactions among multi-agent. Most of the past research results thus are based on the probabilistic completeness. However, the practicality and effectiveness of the solution from the probabilistic completeness is significantly reduced by heavy computational burden. In this paper, we propose a practically applicable solution technique for multi-agent planning problems, which assures a reasonable computation time and a real world application for more than 3 multi-agents for the case of general shaped paths in agent movement. First, to reduce the computation time, a collision map is utilized for detecting potential collisions and obtaining collision-free solutions for multi-agents. Second, to minimize the maximum of multi-agent task execution time, a method is developed for selecting an optimal priority order. Simulations are finally provided for more than 20 agents to emphasize the effectiveness of the proposed interactive approach to multi-agent planning problems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.12
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• pp.1275-1283
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• 2014

Characteristics of PCM(Pulse Code Modulation) waveform are suitable for target tracking. Especially in terms of dwell time, it is desirable to detect and track a moving target with the single PCM waveform for a MFR(Multi-Function Radar) which carries out multiple tasks. General PCM waveform processing includes Doppler filter bank caused by the characteristics of ambiguity function, to detect target and estimate Doppler frequency, which induces hardware burden and computational complexity. We propose a ML(Maximum Likelihood) based Doppler estimator for a PCM waveform, which is the closed form suboptimal solution and computationally efficient to estimate Doppler frequency and detect a moving target.

• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.57-69
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• 2022

Recently, as interest in self-driving cars has increased worldwide, research and development on the Advanced Driver Assist System is actively underway. Among them, the purpose of Adaptive Cruise Control (ACC) is to minimize the driver's driving fatigue through the control of the vehicle's longitudinal speed and relative distance. In this study, for the research of the ACC test in the real environment, the real-road test was conducted based on domestic-road test scenario proposed in preceding study, considering ISO 15622 test method. In this case, the distance measurement method using the dual camera was verified by comparing and analyzing the result of using the dual camera and the result of using the measurement equipment. As a result of the comparison, two results could be derived. First, the relative distance after stabilizing the ACC was compared. As a result of the comparison, it was found that the minimum error rate was 0.251% in the first test of scenario 8 and the maximum error rate was 4.202% in the third test of scenario 9. Second, the result of the same time was compared. As a result of the comparison, it was found that the minimum error rate was 0.000% in the second test of scenario 10 and the maximum error rate was 9.945% in the second test of scenario 1. However, the average error rate for all scenarios was within 3%. It was determined that the representative cause of the maximum error occurred in the dual camera installed in the test vehicle. There were problems such as shaking caused by road surface vibration and air resistance during driving, changes in ambient brightness, and the process of focusing the video. Accordingly, it was determined that the result of calculating the distance to the preceding vehicle in the image where the problem occurred was incorrect. In the development stage of ADAS such as ACC, it is judged that only dual cameras can reduce the cost burden according to the above derivation of test results.

• Research in Community and Public Health Nursing
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• v.13 no.4
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• pp.648-667
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• 2002

This was a descriptive study designed to identify the level of coping method and its influencing factors on the family caregivers of demented patients, and resolve the family caregivers' level of stress. The data were collected from September 10 to October 10, 2001. Subjects for this study were recruited from four clinics, which were chosen from 15 clinics located in Chunbuk-Do as the study sites because of their cooperation for the study. They were similar in terms of size, the characteristics of the local community. and the population and registration status of the demented patients. The instruments used for the study were as follows: 1. Problematic behaviors of demented patients are measured by the Memory and Behavior Problem Checklist (Zarit, 1980), and the Linguistic Communication Symptoms Questionnaire (Bayles and Tomoeda, 1991) 2. The ability to carry out daily activities was measured using the Barthel Index (1965) and Katz Index (1963), which as well-known ADL assessment methods. 3. Burden was measured using Cost of Care Index by the Kosberg and Cairl (1986). 4. Coping strategy was measured Bell's 18 methods (1977). The data were analyzed using SPSS/PC. The study results were as follows: 1. The total stress score was 2.90 out of a maximum score of 5. The highest score reported was 3.09 on the dimension of restriction of individual and social activities, and the lowest region reported was 2.58 on the dimension of mental and physical health. 2. The total score of the coping method was 2.65 out of a maximum score of 5. The highest score reported was 4.01 on the dimension of thinking that includes an ideation such that it is better than any possible worst case, and the lowest score reported was 1.45 on the dimension of the self-image as a scapegoat. 3. There were significant differences in coping method among the subjects by age (F=2.752 p=0.04), caregiver (F=4.33 p=0.003), care-giving period (F=2.68 p=0.049), and dementia stage (F=2.87 p=0.034). 4. There were highly negative correlations ($\gamma$=-0.301 p=0.000) between problematic behaviors of demented patients and the coping method of their family caregivers. The highest correlation coefficient ($\gamma$=-0.339 p=0.000) was found between aggressive behaviors of the demented patients and the coping method of their family caregivers. 5. There was a low negative correlation ($\gamma$=-0.201 p=0.019) between the ADL of the demented patients and the coping method of their family caregivers. 6. There were highly negative correlations ($\gamma$=-0.213 p=0.005) between stress and the coping method of the family caregivers. The highest correlation was found between financial burden ($\gamma$=-.327 P=.000) and the coping method of the family caregivers. There was no significant correlation among unpleasant aspects of the demented patients, willingness to the demented patients, and the coping method of the family caregivers.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.3
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• pp.106-120
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• 2010

Objectives: Sanjointang has been clinically used much for treating sleeplessness. However, the effects of Sanjointang in artificial sleep deprivation situations are not known. The purpose of this study is to evaluate the heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, and -dp/dt / +dp/dt ratio which are related to the hemodynamic functions of the heart by using sleep-deprived Sparague-Dawley rats, in order to clarify the impact of Sanjointang on hemodynamic functions of the heart of sleep deprived rats. Methods: Eighteen hearts were removed from the male Sparague-Dawley rats weighting about 180g were perfused by the Langendorff technique with modified 37 Krebs-Henseleit's buffer solution at a constant perfusion pressure (60mmHg). They were randomly assigned to one of the following three groups, 1) Normal group (those which did not have sleep deprivation and received normal saline administration), 2) Control group (sleep deprived and normal saline administered), 3) Sample group (sleep deprived and Sanjointang was administered). Control and sample groups rats were deprived 96 hours of sleep by using the modified multiple platform technique. Heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, -dp/dt / +dp/dt ratio were evaluated at baseline after the administration of either normal saline or Sanjointang. Results: The heart rate and -dp/dt / +dp/dt ratio was significantly decreased in rats with 96 hours of sleep deprived significantly decreased. The change in the heart rate after administering Sanjointang did not show any significant difference. The left ventricular systolic pressure of the removed heart significantly decreased due to Sanjointang administration, while the left ventricular diastolic pressure significantly increased (p<0.05). The +dp/dt maximum and -dp/dt maximum both significantly decreased in the removed heart after administering Sanjointang. (p<0.05). There was no significant difference observed in the -dp/dt / +dp/dt ratio after administering Sanjointang. Conclusions: According to the results above, sleep deprivation significantly decreases heart rate and -dp/dt / +dp/dt ratio. This is considered as a result of exhaustion due to accumulation of fatigue. Meanwhile, Sanjointang reduced left ventricular systolic pressure and raised left ventricular diastolic pressure, and relieved the contractility and relaxation of the myocardium. Consequently, this reduces the burden of the heart and creates a relatively stabilized heart condition similar to a sleeping condition.