• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.315-318
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• 1988

THE STUDY ABOUT CHARACTERISTICS OF PHOTO RESIST ITSELF (MINIMUM RESOLUTION, DEPTH OF FOCUS MARGIN AND CRITICAL DIMENSION CONTROL LATITUDE) WAS DONE AND REPORTED. THREE TYPES OF PHOTO RESISTS WERE TESTED. THE FIRST IS THE LOW MOLECULAR WEIGHT PHOTO-RESIST SHOWING THE NARROW DISTRIBUTION OF MOLECULAR WEIGHT (LOW MOLECULAR WEIGHT CONTROL TYPE), THE SECOND IS A PHOTO-RESIST CONTAINING THE INNER CONTRAST ENCHANCEMENT MATERIAL (INNER CEM TYPE) AND THE THIRD IS A NORMAL PHOTO-RESIST (HIGH MOLECULAR WEIGHT TYPE). THE INNER CEM TYPE AND THE LOW MOLECULAR WEIGHT CONTROL TYPE PHOTO-RESIST ARE MORE IMPROVED PHOTO-RESISTS. IT PROVED THAT THE MINIMUM RESOLUTION WAS IMPROVED BY 0.2 - 0.3 um, THE DEPTH OF FOCUS MARGIN WAS IMPROVED BY 0.8 - 1.2 um AND THE C.D. CONTROL LATITUIDE WAS IMPROVED.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.526-535
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• 2016

In this study, the estimating weight data of eight leading ships of Korea navy were processed by comparing with the final weight data of their incline test results statistically, and are analyzed as follows; The maximum criteria of the weight margins of Korea naval ship in the preliminary and detailed design phases seem to be appropriate values, but the minimum criteria would be advisable to update more reasonable values. And, the limitation that the acceptable deviation of lightship weight should be 10 % of the lightship weight on a naval ship's ROC(Required Operational Capabilities) is recommended to be prohibited, because it comes from the weight estimation which has considerable uncertainty and it may also drop off design flexibility. Finally, the SWBS(Ship Work Breakdown System) groups which have larger deviation values in the estimating weight of naval ships are necessary to improve their accuracies, and to upgrade their weight database continuously.

• The Korean Journal of Applied Statistics
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• v.16 no.2
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• pp.261-271
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• 2003

Support Vector Machines (SVMs) provide a powerful performance of the learning system. Generally, SVMs tend to make overfitting. For the purpose of overcoming this difficulty, the definition of soft margin has been introduced. In this case, it causes another difficulty to decide the weight for slack variables reflecting soft margin classifiers. Especially, the error of soft margin algorithm can be bounded by a target margin and some norms of the slack vector. In this paper, we formulate a new soft margin algorithm considering the bound of corruption by noise in data directly. Additionally, through a numerical example, we compare the proposed method with a conventional soft margin algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.146-154
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• 1991

As the application of robotic systems expand its scope, more research efforts are given in providing mobility to the robotic systems so that they can travel across various paths including those with formidable obstacles such as stairways or rough terrains. Legged locomotion is mainly concerned because the walking motion, like that of animal behavior, has many advantages over wheel type or track type locomotion especially in rough terrain. Walking robot, in general, having a discrete number of legs, have inherently low static stability. Static stability can be increased to a certain degree, by improving walking method, but it has many limitations such as reduced travel speed. A very promising possibility lies in the use of balancing weight, nevertheless its actual implementation is very rare. In this study, a 4-legged walking machine is developed and the static stability margin is increased with the balancing weight. In the future, this robot will be used to take an experiment on the walking in mush terrain.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.145-152
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• 1998

This paper presents an optimum design of a rotor-bearing spindle system for a ultra centrifuge (80,000 RPM) supported by ball bearings with nonlinear stiffness characteristics. To obtain the nonlinear bearing stiffnesses, a ball bearing is modeled in five degrees of freedom and is analyzed quasi-statically. The dynamic behaviors of the nonlinear rotor-bearing system are analyzed by using a transfer-matrix method iteratively. For optimization. we use the cost function that simultaneously minimizes the weight of a rotor and maximizes the separation margins to yield the critical speeds as far from the operating speed as possible. Augmented Lagrange Multiplier (ALM) method is employed for the nonlinear optimization problem. The result shows that the rotor-bearing spindle system is optimized to obtain 9.5％ weight reduction and 21％ separation margin.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.214-234
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• 1995

The purpose of this work was to study the compatibility of several commercially available dentin adhesives with composite resins. In this study, V-shaped cavity preparations were created on both buccal and lingual surfaces of 60 extracted human premolars($3mm{\times}3mm{\times}2mm$ deep). Preparations were located such that the occlusal margins were on the enamel and the gingival margins were on the cementum(1mm below the CEJ). These specimens were randomly divided into three equal groups. Three dentin adhesives(Scotchbond Multi-Purpose, All Bond 2, Prisma Universal Bond 3)were applied to the cavity in accordance with each manufacturer's instructions. The teeth in each group were restored with four composite resins(Silux plus, Z100, Bisfil, Prisma TPH) in three increments, with each increment light-cured for 40 seconds. All specimens were exposed to 500 cycles of thermal stress. Specimens then placed in a silver nitrate solution(50% by weight) and stored in darkness for 24 hours. They were then immersed for 6 hours in photographic developing solution under flourescent light. Specimens were sectioned buccolingually through the center of the restoration and observed under a binocular stereoscope. To compare the marginal leakage, ANOVA and Dunkan's multiple range tests were used in analysis. Selected samples were further studied using scanning electron microscopy(XL20, Philips, The Netherlands). The results were as follows. 1. In all groups, the enamel margin showed significantly less leakage than the cementum margin. 2. No statistically significant differences were found in microleakage when composite resins were used with their proprietary dentin adhesives. 3. In comparison between dentin adhesives, Prisma Universal Bond 3 showed significantly less leakage at the enamel margin and Scotch bond multi-purpose showed significantly less leakage at the cementum margin than the other groups. 4. In comparison between composite resins, Silux Plus showed significantly more leakage than other groups at the enamel margin and no statistically significant differences were found in microleakage at the cementum margin. 5. According to the backscattered scanning electron microscope, microleakage occurred via gaps at the dentin adhesives/dentin interface.

• Korean Journal of Applied Biomechanics
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• v.26 no.4
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• pp.377-382
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• 2016

Objective: The purpose of this study was to provide data on gait characteristics of K-pop professional dancers. Method: Participants were divided into four groups: male dancers (n=10, age: $28.2{\pm}3.4years$, height: $175{\pm}6cm$, weight: $68.9{\pm}5.6kg$), female dancers (n=10, age: $26.7{\pm}3.1years$, height: $162{\pm}4cm$, weight: $52.1{\pm}3.7kg$), non-dancer males (n=10, age: $25.2{\pm}2.6years$, height: $171{\pm}6cm$, weight: $66.4{\pm}5.3kg$), or non-dancer females (n=10, age: $26.2{\pm}3.0years$, height: $161{\pm}5cm$, weight: $56.4{\pm}6.7kg$). Twelve infrared cameras (Qualisys, Oqus 500, Sweden, 150 Hz.) were used to capture three-dimensional motion data. Gait motion data of professional dancers and ordinary persons were obtained. Results: K-pop dancers' dynamic stability during the female toe off event and the male heel contact event was better compared with that of ordinary persons in the front-rear direction. In addition, the results showed a significant difference in the margin of stability (MoS). However, the medial-lateral direction of both female and male dancers during heel contact and the toe off event was more stable compared with ordinary person, who exhibited an increased MoS than did the dancers. Conclusion: This study aimed to investigate the gait characteristics of K-pop professional dancers in comparison with ordinary persons using gait parameters and MoS. The stability of K-pop professional dancers' dynamic gait in the front-rear direction was better than that in the medial-lateral direction. Therefore, further studies in which the dance movements of K-pop dancers are sub-divided and analyzed will be necessary to reduce related injury.

• Neonatal Medicine
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• v.25 no.1
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• pp.1-6
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• 2018

Extremely low birth weight infants remain at increased risk of intraventricular hemorrhage from the fragile vascular bed of the germinal matrix; the roles of hypotension (ischemia) and reperfusion (hyperemia) in the development of intraventricular hemorrhage are still debated. Cerebrovascular pressure autoregulation protects the brain by maintaining constant cerebral blood flow despite changes in blood pressure. The ontogeny of cerebrovascular pressure autoregulation has not been well established and uncertainty remains about the optimal arterial blood pressure required to support brain perfusion. Another important aspect of premature cerebral hemodynamics is the critical closing pressure--the arterial blood pressure at which cerebral blood flow ceases. Interestingly, in premature infants, the critical closing pressure approximates the mean arterial blood pressure. Often in this unique population, cerebral blood flow occurs only during systole when the diastolic arterial blood pressure is equal to the critical closing pressure. Moreover, the diastolic closing margin, a metric of cerebral perfusion that normalizes diastolic arterial blood pressure to the critical closing pressure, may be a better measure than arterial blood pressure for defining cerebral perfusion in premature infants. Elevated diastolic closing margin has been associated with intraventricular hemorrhage. This review summarizes the current state of understanding of cerebral hemodynamics in premature infants.

• Earthquakes and Structures
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• v.19 no.3
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• pp.197-214
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• 2020

Diagrid structures have been introduced as a fairly modern lateral load-resisting system in the design of high-rise buildings. In this paper, a novel diagrid system called tube-in-tube diagrid building is introduced and assessed through pushover and incremental dynamic analyses. The main objectives of this paper are to find the optimum angle of interior and exterior diagrid tube and evaluate the efficiency of diagrid core on the probability of collapse comparing to the conventional diagrid system. Finally, the seismic performance factors of the proposed system are validated according to the FEMA P695 methodology. To achieve these, 36-story diagrid buildings with various external and internal diagonal angles are designed and then 3-D nonlinear models of these structures developed in PERFORM-3D. The results show that weight of steel material highly depends on diagonal angle of exterior tube. Adding diagrid core generally increases the over-strength factor and collapse margin ratio of tall diagrid buildings confirming high seismic safety margin for tube-in-tube diagrid buildings under severe excitations. Collapse probabilities of both structural systems under MCE records are less than 10%. Finally, response modification factor of 3.0 and over-strength factor of 2.0 and 2.5 are proposed for design of typical diagrid and tube-in-tube diagrid buildings, respectively.

• Journal of the Korea Society of Computer and Information
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• v.19 no.3
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• pp.155-161
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• 2014

The objective of this study is to weight analysis portable backpack system of infantry weapon systems for ergonomic design in manual materials handling tasks. For the product design, we analyzed the ergonomic guidelines and status of similar weapon systems by comparing the efficient operation performance provide for the basic data. Result of this study, the relationship between portability and mobility presented for schematic. In the short distance of the short biomechanical criterion, 1-2 hours in the middle of moving psychophysical criterion, 4 hour or more long-distance criterion applied for the physiological criterion for easy of trade-offs that need to be considered. This study suggests for 4 research items for infantry backpack system in manual materials handling tasks. Throughout the result of anthropometric populations, the 5%tile body weight for -0.91kg but 95%tile in 34.17kg considered to be margin for free, easy and efficient operation for the weight margin between portability and mobility in manual materials handling tasks.