• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.228-231
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• 2003

This paper presents the leg trajectory generation for the quadruped robot with genetic-fuzzy algorithm. To have the nobility even at uneven terrain, a robot is able to recognize obstacles, and generates moving path of body that can avoid obstacles. This robot should have its own avoidance algorithm against obstacles, forwarding to target without collision. During walking period, n robot recognizes obstacle from external environment with a PSD and some interface, and this obstacle information is converted into proper the body rotation angle by fuzzy inference engine. After this process, we can infer the walking direction and walking distance of body, and finally can generate the optimal Beg trajectory using genetic algorithm. All these methods are verified with PC simulation program, and implemented to SERO-V robot.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.725-734
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• 2009

Maxwell stress tensor is one of the methods which are generally used for electromagnetic force calculation. In this paper, it is presented that Maxwell stress tensor T and n${\cdot}$T have no physical meaning and therefore should not be used as sources of mechanical force for deformations or dynamics. The divergence of Maxwell stress tensor ${\nabla}{\cdot}T$ is the one which can acquire a physical identity and is electromagnetic body force density by an action at a distance like a gravity. This result can be derived from the principle of power balance, and also verified by some thought experiments. The virtual air-gap approach is proposed as a valid solution for the calculation of the body force.

• Journal of Astronomy and Space Sciences
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• v.31 no.3
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• pp.187-197
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• 2014

We have investigated the dynamical stability of the proposed companions orbiting the Algol type short-period eclipsing binary SW Lyncis (Kim et al. 2010). The two candidate companions are of stellar to substellar nature, and were inferred from timing measurements of the system's primary and secondary eclipses. We applied well-tested numerical techniques to accurately integrate the orbits of the two companions and to test for chaotic dynamical behavior. We carried out the stability analysis within a systematic parameter survey varying both the geometries and orientation of the orbits of the companions, as well as their masses. In all our numerical integrations we found that the proposed SW Lyn multi-body system is highly unstable on time-scales on the order of 1000 years. Our results cast doubt on the interpretation that the timing variations are caused by two companions. This work demonstrates that a straightforward dynamical analysis can help to test whether a best-fit companion-based model is a physically viable explanation for measured eclipse timing variations. We conclude that dynamical considerations reveal that the proposed SW Lyncis multi-body system most likely does not exist or the companions have significantly different orbital properties from those conjectured in Kim et al. (2010).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.111-116
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• 1987

The accurate prediction of the ship wave resistance is very important to design ships which operate satisfactorily in a wave environment. Thus, work should continue on development and validation of methods to compute ship wave patterns and wave resistance. Research efforts to improve the prediction of ship waves and wavemaking resistance are categorized in two major areas. First is the development of higher-order theories to take account of the nonlinear effect of the free surface condition and improved analytical treatment of the body boundary condition. Second is the development of direct numerical methods aimed at solving body and free-surface boundary conditions as accurately as possible. A new formulation of the slender body theory for a ship with constant speed is developed by Maruo. It is quite different from the existing slender ship theory by Vossers, Maruo and Tuck. It may be regarded as a substitute for the Neumann-Kelvin approximation. In present work, the method of asymptotic expansion of the Kelvin source is applied to obtain a new wave resistance formulation in fluid of finite depth. It takes a simple form than existing theory.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.31-38
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• 2020

The study evaluated the accuracy and intra-rater reliability for OWAS (Ovako Working posture Analysing System), RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment) to improve their evaluation accuracy and reliability. Participants (n = 163) with undergraduate degree were recruited in this study and trained for 6 hours about the ergonomic assessment methods. Ergonomic assessments were conducted using OWAS, RULA, and REBA for a representative work with dynamic posture found in manufacturing industries. The study compared action categories (overall level) and detailed evaluation scores for individual body part. Action categories of the participants significantly differed from the golden reference defined by ergonomic experts. The participants underrated or omitted scores for truck (37.4% of the participants) and legs (52.8%) in OWAS. Similarly, the participants underrated or omitted additional scores for all body parts except the hand and wrist in RULA (53.5%) and REBA (54.8%). On the other hand, the participants overrated scores for the hand and wrist in RULA (55.2%) and REBA (39.9%). The results found in this study can help of selecting focus points and parts during assessment and education to improve accuracy and reliability of the ergonomic assessment methods.

• Safety and Health at Work
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• v.14 no.4
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• pp.457-466
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• 2023

Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28℃, and the weight, inhalation resistance (R_f), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the R_f and 10-200 nm total aerosol penetration (P_t) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the R_f, P_t, and absorbed water all increased significantly. Conclusions: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.

• Korean Journal of Community Nutrition
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• v.20 no.5
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• pp.362-374
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• 2015

Objectives: This study was performed to investigate the effects of overestimation of their own body shape on weight control behaviors, mental condition, physical activity, dietary behavior, health-related quality of life, and nutritional status among young Korean females. Methods: A total of 1,514 women aged 20-39 years who are not pregnant and lactating among those who participated in the Fifth Korea National Health and Nutrition Examination Survey (2010~2011), were analyzed and grouped into underestimation (n=120), normal estimation (NE, n=840), and overestimation (OE, n=554), based on their body perception compared to actual percent ideal body weights. Variables were compared between OE group and NE group. Results: The subjects in OE group were significantly younger (29.5 vs. 30.5 years, respectively p < 0.05) and had lower body mass index (20.9 vs. 22.2 respectively, p < 0.01), health-related quality of life measured by EQ-5D (EuroQol-5 Dimension)(0.97 vs. 0.98 respectively, p < 0.05), nutrition adequacy ratio (NAR) of protein (0.91 vs. 0.93 respectively, p < 0.05), phosphorous (0.93 vs. 0.96 respectively, p < 0.05), and iron (0.70 vs. 0.75 respectively, p < 0.01), and index of nutrition quality (INQ) of iron (0.84 vs. 0.89 respectively, p < 0.05) compared to those in the NE group. The results of logistic regression showed that unmarried status (OR 1.32; 1.01~1.72) and severely underweight/underweight status (OR 1.94; 1.01~3.75)/(OR 1.81; 1.34~2.45) were significantly related to the probability of overestimation by the subjects. Significantly more women in OE group practiced fasting, skipping meals, and taking prescribed pills to lose body weights and had skipped breakfast compared to those in the NE group. Conclusions: The results of this study suggested that the Korean young women's distorted perception of own body shape may be associated with undesirable weight control behavior, low quality of life, and lower nutritional status. Therefore, nutrition education for this group should include information on correct body shape perception and its importance.

• The Journal of Internal Korean Medicine
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• v.37 no.1
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• pp.8-15
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• 2016

Objectives: To provide information on the safety of GST (Gami-Sasangja-tang), we carried out a single oral dose-increasing toxicity test of GST in beagle dogs.Materials and Methods: Six beagle dogs (three males and three females) were randomly assigned to two groups (experimental group: n=4, control group: n=2). The experimental group (two males, two females) was given oral doses of GST in increasing order (1,250, 2,500, and 5,000 mg/kg) at three-day intervals. After administration, the participants’ mortality, clinical signs, and body weight changes were monitored for two weeks. After two weeks, all dogs were sacrificed for autopsy.Results: Temporary vomiting was observed according to increasing dosage (n=1, 250 mg/kg; n=4, 2,500 and 5,000 mg/kg). Transient diarrhea was observed on the second and third dosing day (n=1, 2,500 mg/kg; n=2, 5,000 mg/kg). Temporary salivation was noted on the third dosing day (n=3, 5,000 mg/kg). Compound-colored stool was observed in all dogs fed the GST on all dosing days and also on the following days. We found no mortality and no abnormalities in the clinical signs, body weight, and gross findings in any of the dogs tested.Conclusions: The maximum tolerated dose was over 5,000 mg/kg for both male and female dogs.

• Journal of Oriental Neuropsychiatry
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• v.32 no.3
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• pp.207-217
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• 2021

Objectives: The objective of this study was to perform a scoping review to describe clinical study trends on Qigong in order to identify further directions of Qigong in Korean medicine. Methods: Under the Arksey and O'Malley methodological framework, PubMed was searched to identify articles published from January 1, 2019 to June 28, 2021. A total of 224 articles were retrieved. Results were systematically filtered by two independent reviewers based on inclusion/exclusion criteria. Publication information, disease, intervention and research results of a total of 153 articles were extracted and analyzed. Results: Asia had the largest number of Qigong studies (82 studies, 65%). Most research studies were conducted in the academic field of Medicine (n=109, 86.5%), including Complementary and Alternative Medicine (n=35), Medicine (miscellaneous) (n=15), and Oncology (n=15). Based on ICD-10 classification, Mental and Behavioral Disorder (n=25, 19.8%) was the most frequently analyzed decease, followed by Neoplasm (n=24) and Disease of the Nervous system (n=12). Almost half of all studies were Systematic Reviews. RCTs only accounted for 25.4%. Interventions were very diverse and inconsistent. Sixty (47.6%) studies analyzed Qigong as a single intervention. In 66 cases, Qigong was analyzed as part of a large category such as Mind-Body intervention. Most studies designed a Donggong (動功) program. The age of the population was relatively high as 47.1% of all studies were conducted on middle aged or older adults. Conclusions: These findings suggest that further standardized research on Qigong, especially Junggong (靜功), needs to be conducted by developing research protocols and practice programs to verify effects of Qigong and utilize Qigong as a medical intervention in Korean Medicine.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.1-1
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• 1987

The accurate prediction of the ship wave resistance is very important to design ships which operate satisfactorily in a wave environment. Thus, work should continue on development and validation of methods to compute ship wave patterns and wave resistance. Research efforts to improve the prediction of ship waves and wavemaking resistance are categorized in two major areas. First is the development of higher-order theories to take account of the nonlinear effect of the free surface condition and improved analytical treatment of the body boundary condition. Second is the development of direct numerical methods aimed at solving body and free-surface boundary conditions as accurately as possible. A new formulation of the slender body theory for a ship with constant speed is developed by Maruo. It is quite different from the existing slender ship theory by Vossers, Maruo and Tuck. It may be regarded as a substitute for the Neumann-Kelvin approximation. In present work, the method of asymptotic expansion of the Kelvin source is applied to obtain a new wave resistance formulation in fluid of finite depth. It takes a simple form than existing theory.