• Honam Mathematical Journal
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• v.31 no.1
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• pp.1-9
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• 2009

In this paper we establish strict lower bounds on number of sticks necessary to construct stick presentations of nontrivial or almost trivial ${\mu}$-curves.

• Honam Mathematical Journal
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• v.30 no.1
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• pp.165-170
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• 2008

We will examine the stick number of knots on the cubic lattice which is called the lattice stick number. The lattice stick numbers of knots $3_1$ and $4_1$ are known as 12 and 14, respectively. In this paper, we will show that only $3_1$ and $4_1$ have representations of irreducible non-trivial polygons, both numbers of whose sticks parallel to the y-axis and the z-axis are exactly four.

• Tribology and Lubricants
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• v.34 no.6
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• pp.279-283
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• 2018

In this study, we investigate the behavior of abrasive particles and change of the stick-slip pattern according to chemical mechanical polishing (CMP) process parameters when a large number of abrasive particles are fixed on a pad. The CMP process is simulated using the finite element method. In the simulation, the abrasive grains are composed of those used in the actual CMP process. Considering the cohesion of the abrasive grains with the start of the CMP process, abrasive particles with various sizes are fixed onto the pad at different intervals so that stick-slip could occur. In this analysis, we determine that when the abrasive particle size is relatively large, the stick-slip period does not change as the pressure increases while the moving speed is constant. However, if the size of the abrasive grains is relatively small, the amount of deformation of the grains increases due to the elasticity of the pad. Therefore, the stick-slip pattern may not be observed. As the number of abrasive particles increases, the stick-slip period and displacement decrease. This is consistent with the decrease in the von Mises yield stress value on the surface of the wafer as the number of abrasive grains increases. We determine that when the number of the abrasive grains increases, the polishing rate, and characteristics are improved, and scratches are reduced. Moreover, we establish that the period of stick-slip increases and the change of the stick-slip size was not large when the abrasive particle size was relatively small.

• Journal of KSNVE
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• v.10 no.3
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• pp.451-456
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• 2000

In this paper a discrete time model for the identification of nonlinear vibration system with stick-slip friction is proposed. The proposed model can handle the highly nonlinear behavior of the friction such as stick-slip phenomenon and Stribeck effect. The basic idea of the proposed model is as follows : If the nonlinearity of the system can be predicted as a simple function then this nonlinear function term cab be directly used in the discrete time model. By doing this the number of nonlinear terms in the model can be much less than those of NARMAX model which is widely used nonlinear discrete model. The simulation result shows that the proposed model can estimate the response of the nonlinear vibration system with stick-slip friction very well with less computational effort.

• The Korean Nurse
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• v.34 no.2
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• pp.45-57
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• 1995

A study .to identify an occupational hazards for hospital working health care providers from needle stick injury as an occupational hazards of health care providers in hospital and prevention A survey of 2430 health professionals (2184 nurses, 182 doctors, and 64 Lab technicians) was conducted to describe and provide information about 1) the experience of needle stick. 2) the number of needle stick, 3) the treatment after needle stick. 3) the situation of needle stick, 4) the report of needle stick, 5) the cause of needle stick, 6) the discard method of used needles, and 7) how to worry about getting infection disease after needle stick. Data were collected using questionnarires constructed by the authors and tested by a pilot study. Results of the study showed that 96.7% of the sample had an experience of needle stick (96.8% of the nurses, 96.7% of the doctors, and 92.2% of Lab technicians). Seventy seven percent of the sample experienced less than 10 needle sticks, 19% of the sample experienced 11 to 20 needle sticks, and the rest of the sample experienced more than 20 needle sticks. The situations where needle sticks occurred include intrvenous injection (36.5%), intramuscular injection (21.6%), blood withdraw (17.8%), and preparation(11.8%). The study showed that needle sticks (67.5%) usually occurred after client treatment. Health professionals used recapping method (55%) after they used needles. Needle sticks were predominantly caused by the carelessness of health professionals (61%), After needle sticks, 88.2% of the sample subjects treated needle sticks using disinfection technique by themselves. Most of health professionals (92.6%) did not report the accident. and 95.6% of them did not receive any test or further treatment. After needle sticks, 87.8% of nurses, 83.6% of doctors, and 96.6% of lab technicians worried about hepatitis infection. 'Health professionals also worried about AIDS infection, tetanus, venereal infection, and skin injury. These findings suggest that health professionals are at high-risk of needle stick and fail to report needle stick accidents. They should pay more attention to needle stick in order to avoid unwanted infection.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.767-776
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• 2010

Frontier (1976) suggested a criterion based on the expected length of ordered random intervals under the Broken-stick model (Barton and David, 1956) to determine the optimal number of principal components retained. It is considered to be one of the methods that provide the most consistent simulation results (Jackson, 1993). This study is aimed to propose a method using the distribution of ordered random intervals to evaluate the contribution of principal components. We also examine several types of Gini indices along with the corresponding Lorenz curves to visualize the overall equivalence of those contributions.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.491-495
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• 2015

Currently, selfie stick, a monopod take selfie photographs, got its popularity. Cradle used to connect selfie stick and smartphone usually uses electric force of spring to get smartphone fixed. But, using electric forces makes it hard to attach and detach smartphone from the cradle and gives possibility of smartphone falling down. CoQue suggests new solution of smartphone cradle by using cable tie (patent number US 8407863 B2) instead of electric force. It will give more easy and stable way of using selfie stick.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.287-296
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• 2011

The white stick mainly used for visually impaired person has difficulty in providing location information and effective countermeasures for emergency situations encountered during walking as well as detecting floating obstacles on the ground. In this paper, we propose a machine-to-machine based intelligent walking assistance system for safe and convenient walking of the visually impaired. The proposed system consists of a walking assistance stick used by the visually impaired and a server supporting multiple stick users in remote places through mobile communication networks. The stick equipped with ultrasonic sensors, GPS(global positioning system) receiver and vibrator not only detects floating obstacles, but also offers stick users with present location identification utilizing a text-to-voice conversion technology. Besides providing geographic information, the server notifies the emergency locations of users to guardian and aid agency, and it provides log information during walking such as the place, time and the number of accidents. Test results with a developed prototype system have shown that the system properly performs the functions and satisfies overall system performance.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1274-1280
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• 2001

The fretting wear behavior of the contact between Zircaloy-4 tube and Inconel 600, which are used as the fuel rod cladding and grid, respectively, in PWR nuclear power plants was investigated in air. In the study, number of cycles, slip amplitude and normal load were selected as the main factors of fretting wear. The results indicated that wear increased with load, slip amplitude and number of cycles but was affected mainly by the slip amplitude. SEM micrographs revealed the characteristics of fretting wear features on the surface of the specimens such as stick, partial slip and gross slip which depended on the slip amplitude. It was found that fretting wear was caused by the crack generation along the stick-slip boundaries due to the accumulation of plastic flow at small slip amplitudes and by abrasive wear in the entire contact area at high slip amplitudes.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.2
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• pp.166-172
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• 2007

Purpose: The purpose of this study was to examine the factors influencing glass particle contamination in single dose glass ampules upon opening. Method: The study was single case experimental design. Different methods of opening ampule (hand, wooden stick), different sizes of ampules(1cc, 2cc) and different sizes of needles(17gauge, 23gauge, $5{\mu}m$ filter) were evaluated. Eighteen ampules were randomly assigned in each group. The number of glass ampule particles ${\ge}10{\mu}m$ was counted by microscope. Results: There was no significant difference in the number of particles aspirated by opening methods. But number of glass particles was much lower when using 1cc ampules rather than 2cc ampules and was also much lower when using smaller size needles and needles which include a $5{\mu}m$ filter rather than larger size of needles. Conclusion: We suggest that larger bore or unfiltered needles increase the risk of aspirating more glass particles than smaller bore or filter needles. In addition, these data show that a wooden stick can be used as a method opening glass ampules.