• Journal of the Korean Society of Safety
• /
• v.32 no.6
• /
• pp.40-45
• /
• 2017

Chemical accidents generated during maintenance, repair, and normal operation, such as dispersion, fire, and explosions, can cause massive losses like a 2012 hydro fluorine leak in Gumi, South Korea. Since this accident, many researches have studied physical mitigation systems. However, due to many difficulties including potential costs and lack time, it is really hard for many companies to install mitigation systems without prior knowledge. Thus, the efficacy of mitigation system should be evaluated. This study assesses a dike design considering the fluid velocity at an open hole when a leakage accident occurs. It is assumed that leakage materials follow a free fall motion. Throughout case studies, a current KOSHA guide for a dike design was evaluated and new guidelines handling various conditions were proposed.

• Journal of Mechanical Science and Technology
• /
• v.16 no.1
• /
• pp.1-12
• /
• 2002

In this study, a passive suppression scheme for nonlinear flutter problem of composite panel, which is believed to be more reliable than the active control methods in practical operations, is proposed. This scheme utilizes a piezoelectric inductor-resistor series shunt circuit. The finite element equations of motion for an electromechanically coupled system is derived by applying the Hamilton\\`s principle. The aerodynamic theory adopted for the present study is based on the quasi-steady piston theory, and von-barman nonlinear strain-displacement relation is also applied. The passive suppression results for nonlinear panel flutter are obtained in the time domain using the Newmark-$\beta$ method. To achieve the best damping effect, optimal shape and location of fille piezoceramic (PZT) patches are determined by using genetic algorithms. The effects of passive suppression are investigated by employing in turn one shunt circuit and two independent shunt circuits. Feasibility studies show that two independent inductor-resistor shunt circuits suppresses flutter more effectively than a single shunt circuit. The results clearly demonstrate that the passive damping scheme that uses piezoelectric shunt circuit can effectively attenuate the flutter.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2006.03a
• /
• pp.424-431
• /
• 2006

Many types of tuned mass dampers (TMDs), such as active TMDs, multiple TMDs, hybrid TMDs etc., have been studied to effectively reduce the dynamic responses of a structure subjected to various types of dynamic loads. In this study, we replace a passive damper by a semi-active tuned mass damper to improve the control performance of conventional TMDs (STMD). An idealized variable damping device is used as semi-active dampers. These semi-active dampers can change the properties of TMDs in real time based on the dynamic responses of a structure. The control performance of STMD is investigated with respect to various types of excitation by numerical simulation. Groundhook control algorithm is used to appropriately modulate the damping force of semi-active dampers. The control effectiveness between STMD and a conventional passive TMD, both under harmonic and random excitations, is evaluated and compared for a single-degree-of-freedom (SDOF) structure. Excitations are applied to the structure as a dynamic force and ground motion, respectively. The numerical studies showed that the control effectiveness of STMD is significantly superior to that of the passive TMD, regardless of the type of excitations.

• Journal of Korean Medical classics
• /
• v.6
• /
• pp.189-227
• /
• 1993

I have studied life of Yoon-Dong-Li(尹東里), who applied Un-Ki(運氣) theory to medicine during Suk-Jong(肅宗) to Joong-Jo(正祖) in Yi-Dynasty and also studied his existing writings named ${\ll}$Cho-Chang-kyeol${\gg}$ (草窓訣). The referenced original work prints were based on 1980's print of Chung-Ku oriental medical society and National Central Library and The academy a korean studies possessed print. Studied with these books, I have concluded as follows. 1. Yoon-Dong-Li(尹東里) courtesy name is Ja-Mi(子美), pen name is Cho-Chang(草窓). He was born in 1705, Suk-Jong(肅宗) 31yrs, and died in 1784, Jeong-Jo(正祖) 8yrs in Yi-Dynasty. He had lineage of third-generationed-doctor and learned medicine from his uncle, Yoon-Woo-Kyo(尹雨敎). His father Yoon-Yi-Kyo(尹이敎) gaved him second influence. 2. Confucianal physician in Ming Dynasty You-Bu(劉溥) respected Ju-Ryeom-Kye(周溓溪), confucianist in Song-Dynasty and You-Bu(劉溥) does not removed grass in front of window (because in chinese, Cho-Charig(草窓) means grass in front of window), and named himself Cho-Chang(草窓). Yoon-Dong-Li(尹東里) followed this suit so called himself Cho-Chang (草窓). 3. The main contents of ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣), (運氣衍論) was written in 1725, when Yoon-Dong-Li(尹東里) was 21yrs old and printed in 1736. The other part of ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣), (用藥篇) was written in 1746. These two parts were not written in the satre time. The (運氣衍論) was written llyears earlier than (用藥). Two parts were combined another day and named (草窓訣). 4. Existing ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣) is transcribed printing with the con tent of "Five elements motion and the six kind of natural factors theory" (五運六氣設). Each edition is generally similar in content, but also has different points each other so naw we hardly finds a complete set of works. 5. ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣) is a first technical book which treats of Un-Ki(運氣) theory in korea. 6. The contents of (運氣衍論) of ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣) is mechanism of diease according to excess and insuffciency of five elements motion and six kinds of nalural faclors.and symploms and priscriptions, includes variated priscriptions. 7. Two parts in (運氣衍論) of ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣), 'Sang-tong' (相通) and 'Kak-Tong' (各通), threats of mochanisim of the disease according to five elements. with the principle of inter-promoting and inter-acting, in the change of ten heavenly stems and five elements motion. 8. In the (用藥篇) of ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣) describes priscription for clinical application according to Un-Ki(運氣) and also records about misuse of medicine. 9. In the ${\ll}$Cho-Chang-Kyeol${\gg}$ (草窓訣), most of priscription are common using one, which also found in ${\ll}$Dong-$\breve{U}$i-Bo-Garm${\gg}$ (東醫寶鑑) and there are few of priscriptions hy Yoon-Dong-Li(尹東里).

• Journal of the Korean Home Economics Association
• /
• v.20 no.4
• /
• pp.155-168
• /
• 1982

What is attempted here is to find out an optimum method for the design of physical environments that could save human energy expenditures and safely perform household duties. There are, if any, very little amount of research done in this area. This is particulary so when the work relates to the designing of household storage facilities in the light of the energy metabolism of human body. The first step to this study, therefore, is to find out the ways by which we can determine the energy metabolism of human body accurately. To measure the volume and the concentration of human respiration continuously and automatically, a new apparatus is selected here. This includes the recording system with the Wright Respirometer and the Expired Gas Analyzer as well as the computer system to multiply volume by concentration of human respiration and to integrate them for a given time. Then, the author experimented on the reliability of this apparatus and came to the conclusion that this apparatus satisfied our need to research the energy metabolism of human body. Next, the general plan and procedures to experiment with this apparatus have been determined as follows: 1) subjects are three young and sound females. Their physical characteristics are shown in Table 1 and most approximates the standard characteristics of Japanese females, 2) height of open shelves is selected in such away as to correspond to the respective height of each subject(see Table 2), 3) utensils to be stored are box shaped object, which weight is 0.5kg, 1.0kg, 2.0kg or 3.0kg, 4) working motions are given while one or two hands as to place utensil on each shelf from the standard working board, 85 cm in height and then to place back it on the board from the shelf and repeated in constant velocity as 10 times per a minute, 5) each posture of motion is chosen by each subject in free, 6) procedures of measurement of human energy metabolism ard shown at(6), 1, Section 3 as specific methods for using this apparatus. Findings of this study are as follows: 1. Human energy expenditures for storing utensils on shelves by each subject are shown in quantity more accurately than in any other studies, under varying conditions about height of shelves, load of utensils and working motion with one hand and two hands (see Fig. 8~13 and Table 3). 2. Experimental formulae of human energy expenditure for that work are shown as formula (8), (9) and (10), to generalize results of 1. and to apply those for working motion under given conditions. 3. As results of analysis on gained data, we are able to show the standard model of human energy expenditures for storing untensils on shelves by the standard Japanese female (see Table 7 and Fig. 14).

• Journal of Acupuncture Research
• /
• v.21 no.6
• /
• pp.291-298
• /
• 2004

Objective : This study was designed to investigate the effect of Carthami Flos Herbal-Acupuncture(CF) on Subluxation of the Head of the Radius. Methods : CF was administered one time per 2days. The following points were selected : TE10(天井), LI11(曲池), LI10(手三里). After CF administration conventional body-acupuncture was performed at the same points. We evaluated the patient through Visual Analogue Scale(VAS) and Elbow Range of Motion(ROM). Results : After 6 times of treatment, the patient showed that clinical symptoms was disappeared, VAS changed from 10 to 1 and there was no limitation of ROM. Conclusions : According to the results, CF and early Exercising may have rapid effects on the Subluxation of the Head of the Radius. But further studies are required to prove the effect of CF on Subluxation of the Head of the Radius.

• Journal of The Korean Association For Science Education
• /
• v.15 no.4
• /
• pp.379-393
• /
• 1995

In spite of school science learning, the students' conceptions have not been changed easily. Therefore, to make students overcome their non scientific conceptions has been an important issue in science education. The purpose of this study was to identify the conceptions of students and teachers on the motion of the earth and the moon. The instrument was developed for estimating students' understandings of the concepts related to the motion of the earth and the moon. The validity of the instrument was examined by the specialists in Science Educator and Astronomer. At the same time, the two field trials had been executed, and the items were modified. Also, it consists of 12 items including 9 two-tier multiple choice items and 3 multiple choice items. The population of this study consists of 250 eighth-, 299 tenth-, 292 eleventh-grade students, 134 science teachers in secondary school. SPSS/PC+ was adopted for the statistical analysis. The type of misconceptions possessed students were as follows: 1) At 12:00 noon, the sun is directly overhead. 2) First quarter moon is a half of overall surface of the moon. 3) Air don't rotate with the earth surface because it keeps apart from the earth surface. 4) Summer is warmer than winter, because the earth is nearer from the sun in summer. 5) Whenever season is changed, the direction of rotation axis of the earth is changed. 6) The moon is the brightest at the position of new moon, because the distance between the moon and the sun is the shortest and the moon is received strongest sunlight. 7) The moon is not seen at the position of real full moon, because it is covered with shadow of the earth. 8) When the moon is not seen in the earth, sunlight is not reached at the moon. The major findings were as follows : 1) The middle school students had more misconceptions than those of high school students. And female students had more misconceptions than those of male ones. 2) The rate of correct answer and the type of conception in the tenth grade students were very similar with eleventh grade students. 3) The higher cognitive level, the better development of scientific conception and the less misconception. Also, the correlation coefficient between scientific conception score and GALT score was 0.57. 4) The students in scientific part had higher the rate of correct answer than those of students in human part and the former had less misconception than the latter. 5) The rate of correct answer about model and figure items was lower than descriptive ones, because they did not understand about figures itselves. These types of misconceptions will be used for science instruction and studies of other conceptions need.

• Korean journal of communication and information
• /
• v.26
• /
• pp.7-44
• /
• 2004

This paper proposed semiotic model to explain representation process of time in cinema. Limitations of cinematic narratology which explain representation process of time in cinema were indicated, then alternative explanations of Deleuzian philosophy of cinema were proposed. After discussion about articulations of cinematic code, Deleuzian concept of movement-image was suggested as semiotic minimal unit of cinema. In cinema, Movement-image is divided two different aspects ; "normal movement-image" and "abnormal movement-image". Therefore, two different semiotic representation process of time was reconstructed in accordance with Peircean semiosis theory. In this two different semiotic process, modern cinema emphasize the direct representation process of time with "abnormal movement-image". As Deleuze indicated, The "time-image" is presented in this semiotic process. The "time-image" makes it possible to consider "time itself" as philosophical fact which is laid between reality and cinema, This semiotic process more emphasizes pure expressionality than representationality. Deleuzian philosophical journey through cinema was started in this point.

• Journal of Biomedical Engineering Research
• /
• v.24 no.4
• /
• pp.363-367
• /
• 2003

Contact area and pressure are important factors which directly influence a life of knee implants. Since implant's mechanical functions should be experimentally evaluated for clinical use, many studies using a knee simulator and a pressure sensor system have been conducted. However it has not been reported that the contact pressure's distribution of a knee implant motion was estimated in real-time during a gate cycle. Therefore. the objective of this study was to analyze the contact pressure distribution for the motion of a joint using the knee simulator and I-scan sensor system. For this purpose, we developed a force-controlled dynamic knee simulator to evaluate the mechanical performance of artificial knee joint. This simulator includes a function of a soft tissue and has a 4-degree-of-freedom to represent an axial compressive load and a flexion angle. As axial compressive force and a flexion angle of the femoral component can be controlled by PC program. The pressure is also measured from I-scan system and simulator to visualize the pressure distribution on the joint contact surfaces under loading condition during walking cycle. The compressive loading curve was the major cause for the contact pressure distribution and its center move in a cycle as to a flexion angie. In conclusion, this system can be used to evaluate to the geometric interaction of femoral and tibial design due to a measured mechanical function such as a contact pressure, contact area and a motion of a loading center.

• Journal of the Ergonomics Society of Korea
• /
• v.35 no.1
• /
• pp.39-52
• /
• 2016

Objective: This paper investigates gait changes according to different heel heights and speeds, and the interaction between the effects of the heel height and the speed during walking on stride parameters and joint angles. Furthermore, the relationship among heel height, speed and gait variables is investigated using linear regression. Background: Gait changes by heel height or speed have been studied respectively, but has not been reported whether there is an interaction effect between heel height and speed. It would be necessary to understand how gait changes when a person wears heels in different heights at various speeds, for example, high-heeled walking at fast speed, since it may cause unusual gait patterns and musculoskeletal disorders. Method: Ten females were asked to walk at five fixed cadences (94, 106, 118, 130 and 142 steps/min.) wearing three shoes with different heel heights (1, 5.4 and 9.8cm). Nineteen gait variables were analyzed for stride parameters and joint angles using two-way repeated measure analysis of variance and regression analysis. Results: Both heel height and speed affect movement of ankle, knee, spine and elbow joint, as well as stride length and Double/Single support time ratio. However, there is no significant interaction effect between heel height and speed. The regression result shows linear relationships of gait variables with heel height and speed. Conclusion: Heel height and speed independently affect stride parameters and joint angles without a significant interaction, so the gait variables are linearly amplified or diminished by the two factors. Application: Walking in high heels at fast speed should be careful for musculoskeletal disorders, since the amplified movement of knee and spine joint can lead to increased moment. Also, the result might give insight for animators or engineers to generate walking motion with high heels at various speeds.