• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.32-34
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• 1994

An automatic multiframe procedure for tracking signalized points on multiple, differently moving discontinuous surface is described. The position of markers which attached on human body give us some important information such as velocity, acceleration, angular velocity and angular acceleration, etc, of the rigid objects. Generally, the detected objects occufying some area in images rather than a point because of the generic size of the marks or the smeared effects of the camera. To solve the problem we used a modified clustering algorithm.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.125-136
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• 2012

Wrinkle and fracture are two major defects frequently found in the sheet metal forming process. In this process there are more than one design attributes to optimize and several uncontrollable factors which cannot be ignored in determining the optimal values of design variables. Therefore, attempts to reduce defects through a traditional optimization technique are often led to failures. In this research, a new design method for reducing the wrinkle and fracture under uncontrollable factors is presented by using decision-making theory. To avoid the psychological difficulties in determining the scaling constants of the multi-attribute utility function by using the ordinary lottery questions, a pair-wise comparison procedure is adapted to avoid this problem. The effectiveness of the proposed method is illustrated through a robust design of sheet metal forming process of a side member of an automotive body.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.1-6
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• 2007

Two impedance imaging systems of multi-frequency electrical impedance tomography (MFEIT) and magnetic resonance electrical impedance tomography (MREIT) are described. MFEIT utilizes boundary measurements of current-voltage data at multiple frequencies to reconstruct cross-sectional images of a complex conductivity distribution (${\sigma}+i{\omega}{\varepsilon}$) inside the human body. The inverse problem in MFEIT is ill-posed due to the nonlinearity and low sensitivity between the boundary measurement and the complex conductivity. In MFEIT, we therefore focus on time- and frequency-difference imaging with a low spatial resolution and high temporal resolution. Multi-frequency time- and frequency-difference images in the frequency range of 10 Hz to 500 kHz are presented. In MREIT, we use an MRI scanner to measure an internal distribution of induced magnetic flux density subject to an injection current. This internal information enables us to reconstruct cross-sectional images of an internal conductivity distribution with a high spatial resolution. Conductivity image of a postmortem canine brain is presented and it shows a clear contrast between gray and white matters. Clinical applications for imaging the brain, breast, thorax, abdomen, and others are briefly discussed.

• Journal of Korean Academy of Nursing
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• v.41 no.4
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• pp.550-557
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• 2011

Purpose: The purpose of this study was to investigate the prevalence of depression among school girls in Korea and identify factors influencing the tendency to depression. Methods: A self-report survey was conducted with South Korean middle schoolgirls who were in the 8th and 9th grades. Four hundred and one schoolgirls were included in the study. The instruments utilized in this study were the Center for Epidemiologic Studies - Depression Scale and Social Problem Solving Inventory-Revised. Data were analyzed using descriptive statistics, Pearson correlation and multiple logistic regression with SPSS WIN 14.0 program. Results: The average depression score of the participants was 20.68, which indicates moderate levels of depression. About 35% of the schoolgirls in this study reported a tendency to depression. Significant predictors for depression were 'decreased problem-solving abilities', 'no family members with whom they can discuss their concern', 'decreased satisfaction in relationship with friends', and 'increased negative self-perception of body-image'. Conclusion: The study findings suggest that schoolgirls require special concern regarding the risk of developing depression. Regular depression screening could be beneficial for early detection of depression in schoolgirls and enhancing problem-solving ability could be considered as an effective strategy to reduce the risk of depression among schoolgirls.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.10-20
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• 2007

For spacecraft attitude control, reaction wheel (RW) steering laws with more than three wheels for three-axis attitude control can be derived by using a control allocation (CA) approach.1-2 The CA technique deals with a problem of distributing a given control demand to available sets of actuators.3-4 There are many references for CA with applications to aerospace systems. For spacecraft, the control torque command for three body-fixed reference frames can be constructed by a combination of multiple wheels, usually four-wheel pyramid sets. Multi-wheel configurations can be exploited to satisfy a body-axis control torque requirement while satisfying objectives such as minimum control energy.1-2 In general, the reaction wheel steering laws determine required torque command for each wheel in the form of matrix pseudo-inverse. In general, the attitude control command is generated in the form of a feedback control. The spacecraft body angular rate measured by gyros is used to estimate angular displacement also.⁵ Combination of the body angular rate and attitude parameters such as quaternion and MRPs(Modified Rodrigues Parameters) is typically used in synthesizing the control command which should be produced by RWs.¹ The attitude sensor signals are usually corrupted by noise; gyros tend to contain errors such as drift and random noise. The attitude determination system can estimate such errors, and provide best true signals for feedback control.⁶ Even if the attitude determination system, for instance, sophisticated algorithm such as the EKF(Extended Kalman Filter) algorithm⁶, can eliminate the errors efficiently, it is quite probable that the control command still contains noise sources. The noise and/or other high frequency components in the control command would cause the wheel speed to change in an undesirable manner. The closed-loop system, governed by the feedback control law, is also directly affected by the noise due to imperfect sensor characteristics. The noise components in the sensor signal should be mitigated so that the control command is isolated from the noise effect. This can be done by adding a filter to the sensor output or preventing rapid change in the control command. Dynamic control allocation(DCA), recently studied by Härkegård, is to distribute the control command in the sense of dynamics⁴: the allocation is made over a certain time interval, not a fixed time instant. The dynamic behavior of the control command is taken into account in the course of distributing the control command. Not only the control command requirement, but also variation of the control command over a sampling interval is included in the performance criterion to be optimized. The result is a control command in the form of a finite difference equation over the given time interval.⁴ It results in a filter dynamics by taking the previous control command into account for the synthesis of current control command. Stability of the proposed dynamic control allocation (CA) approach was proved to ensure the control command is bounded at the steady-state. In this study, we extended the results presented in Ref. 4 by adding a two-step dynamic CA term in deriving the control allocation law. Also, the strict equality constraint, between the virtual and actual control inputs, is relaxed in order to construct control command with a smooth profile. The proposed DCA technique is applied to a spacecraft attitude control problem. The sensor noise and/or irregular signals, which are existent in most of spacecraft attitude sensors, can be handled effectively by the proposed approach.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.652-657
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• 2000

The kidneys play a vital role in the maintenance of normal body fluid volumes and in the composition of the extracellular fluid compartments. There are normally more than 2 million functioning glomeruli that regulate total body water and solute concentrations. As renal failure progresses, there is a decrease in the number of functioning nephrons. Chronic renal failure(CRF) is the consequence of a multitude of diseases that cause permanent destruction of the nephron. Azotemia is an elevation in blood urea nitrogen(BUN) and serum creatinine levels subsequent to a decreased glomerular filtration rate(GFR), which results in uremia. This loss of renal function can cause functional and metabolic abnomalities of body. For this problem, oral & maxillofacial surgeons have demanded to routinely treat patients with CRF. However, there has not been a reported case of orthognathic surgery by bilateral sagittal split ramus osteotomy(BSSRO) in patients with CRF, which can cause multiple complications in healthy patients. We report developmental mechanism of complication associated with CRF and preop. and postop. care of orthognathic surgery by BSSRO in Cl III patient with severe chronic renal failure.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.388-399
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• 2016

A motion analysis of an underwater towed cable is a complex task due to its nonlinear nature of the problem. The major source of the nonlinearity of the underwater cable analysis is that the motion of the cable involves large rigid-body motion. This large rigid-body motion makes difficult to use standard displacement-based finite element method. In this paper, the authors apply recently developed nodal position-based finite element method which can deal with the geometric nonlinearity due to the large rigid-body motion. In order to enhance the stability of the large-scale nonlinear cable motion simulation, an efficient time-integration scheme is proposed, namely predictor/multi-corrector Newmark scheme. Three different predictors are introduced, and the best predictor in terms of stability and robustness for impulsive cable motion analysis is proposed. As a result, the nonlinear motion of underwater cable is predicted in a very efficient manner compared to the classical finite element of finite difference methods. The efficacy of the method is demonstrated with several test cases, involving static and dynamic motion of a single cable element, and also under water towed cable composed of multiple cable elements.

• Journal of Korean Public Health Nursing
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• v.14 no.2
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• pp.431-445
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• 2000

In general the prevalence of old people is high and frequently have multiple diseases and symtoms requiring treatment. The nature of illness in the elderly has to be faced, and drugs do have an important part in the treatment of that illness. The purpose of this study were to describe health status and medication, and to provide some basic data for elderly's health education, especially for the right medication. Body mass index, self perceived health status, activities of daily living, disease and experience of past operation were surveyed to recognize the 249 elderly's actual health status. The degree of the elderly's understanding the way of medication, experience of side effects, experience of drug combination and incidence of drug adverse reaction along with drug combination were examined for medication. The aged $women(BMI; 10.7\pm13.3\%)$ overweighed the aged $men(BMI; 4.0\pm10.4\%)$. $69.0\%$ of them recognized their health good. Their activities of daily living were diminished following by the age group(p=0.0068) and relationship with self perceived health status were very significant(p=0.0005). They(192 elderly) suffered from multiple disease such as $osteoarthritis(49.5\%)$, $hypertension(32.0\%)$, gastric $disorder(16.1%)$, $diabetes(14.6\%)$, $osteomalacia(10.9\%)$, cardiovascular $disease(9.9\%)$, senile $cataract(5.7\%)$, skin $rash(5.2\%)$, liver $disease(4.2\%)$, kidney $disease(3.6\%)$, spinal cord $problem(3.6\%)$, respiratory $disease(2.1\%)$ $tuberculosis(1.0\%)\;etc(1.0\%).$ $28.3\%$ of them replied that they had an operation for appendictis senile cataract, peptic ulcer, spinal cord problem, pleurisy, hemorrhoid and the rest. Most of $them(87.4\%)$ knew the way very well how to use drugs, and $21.6\%$ of the replied 171 elderly experienced adverse drug reaction. Drug compliance rate were $high(83.6\%)$. In our study 56.9% of the 167 elderly took several medicine together. And $18.9\%$ of the 95 elderly who did drug combination had an experience of drug interaction. One person kept average 5.5 kinds of drugs at home among 243 elderly. They kept $digestives(79.4\%)$, $ointments(68.7\%)$, $vitamins(59.7\%)$, $analgesics(59.7\%)$, cold $medicines(45.3\%)$ antiarthritic $drugs(33.3\%)$, health $foods(27.7\%)$, antihypertensive $drugs(25.1\%)$, anti peptic ulcer $drugs(24.7\%)$, $laxatives(19.8\%)$, $antacids(16.5\%),\;antibiotics(l6.5\%)$, hypoglycemic $agents(10.3\%)$, cardiac $stimulants(7.0\%)$, $diuretics(4.5\%)$, antiarrhythmic $drugs(4.9\%)$, anti anginal $drugs(4.1\%)$, $hypnotics(3.3\%)$, $etc(38.3\%)$. With this result, we ascertain that polypharmacy in the elderly caused by multiple disease is common, which lead to drug interaction. So our task is to educate elderly how to use drugs in order to maximize their efficiency and to minimize their adverse effects.

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.23.1-23.14
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• 2022

Background: The musculoskeletal disease (MSD) burden is an important health problem among Korean fishers. We aimed to investigate the indicators of the prevalence of MSD and contributions of significant indicators to MSD in Korean fishers. Methods: This cross-section study included 927 fishers (male, 371; female, 556) aged 40 to 79 years who were enrolled from 3 fishery safety and health centers. The outcome variable was one-year prevalence of MSD in 5 body parts (the neck, shoulder, hand, back, and knee). Independent variables were sex, age, educational attainment, household income, job classification, employment xlink:type, hazardous working environment (cold, heat, and noise), ergonomic risk by the 5 body parts, anxiety disorder, depression, hypertension, diabetes, and hyperlipidemia. The adjusted odds ratio of MSDs by the 5 body parts were calculated using multiple logistic regression analysis. We computed the population attributable fraction (PAF) for each indicators of MSDs using binary regression models. Results: The one-year prevalence of MSD in the neck, shoulder, hand, back, and knee was 7.8%, 17.8%, 7.8%, 27.2%, and 16.2% in males vs. 16.4%, 28.1%, 23.0%, 38.7%, and 30.0% in females, respectively. The ergonomic risk PAF according to the body parts ranged from 22.8%-59.6% in males and 22.8%-50.3% in female. Mental diseases showed a significant PAF for all body parts only among female (PAF 9.1%-21.4%). Cold exposure showed a significant PAF for the neck, shoulder, and hand MSD only among female (25.6%-26.8%). Age was not a significant indicator except for the knee MSD among female. Conclusions: Ergonomic risk contributed majorly as indicators of MSDs in both sexes of fishers. Mental disease and cold exposure were indicators of MSDs only among female fishers. This information may be important for determining priority risk groups for the prevention of work-related MSD among Korean fishers.

• ETRI Journal
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• v.37 no.2
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• pp.395-405
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• 2015

We address the problem of uncooperative person recognition through continuous monitoring. Multiple modalities, such as face, height, clothes color, and voice, can be used when attempting to recognize a person. In general, not all modalities are available for a given frame; furthermore, only some modalities will be useful as some frames in a video sequence are of a quality that is too low to be able to recognize a person. We propose a method that makes use of stochastic information updates of temporal modalities and environment estimators to improve person recognition performance. The environment estimators provide information on whether a given modality is reliable enough to be used in a particular instance; such indicators mean that we can easily identify and eliminate meaningless data, thus increasing the overall efficiency of the method. Our proposed method was tested using movie clips acquired under an unconstrained environment that included a wide variation of scale and rotation; illumination changes; uncontrolled distances from a camera to users (varying from 0.5 m to 5 m); and natural views of the human body with various types of noise. In this real and challenging scenario, our proposed method resulted in an outstanding performance.