• Bulletin of the Korean Mathematical Society
• /
• v.55 no.1
• /
• pp.25-40
• /
• 2018

We focus on the structure of the set of noncentral idempotents whose role is similar to one of central idempotents. We introduce the concept of quasi-Abelian rings which unit-regular rings satisfy. We first observe that the class of quasi-Abelian rings is seated between Abelian and direct finiteness. It is proved that a regular ring is directly finite if and only if it is quasi-Abelian. It is also shown that quasi-Abelian property is not left-right symmetric, but left-right symmetric when a given ring has an involution. Quasi-Abelian property is shown to do not pass to polynomial rings, comparing with Abelian property passing to polynomial rings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.48 no.2
• /
• pp.68-74
• /
• 2016

Nanofibrillated cellulose (NFC) was prepared from cotton linter after electron beam irradiation to investigate its effects on the manufacturing efficiency of the NFC preparation and the property changes by the treatment. Mechanical device (Super Masscolloider) was used to prepare the NFC and its passing frequency for each NFC preparation was recorded. More electron beam irradiation resulted in less passing frequency. Alpha cellulose content, molecular weight, crystallinity index, and thermal decomposition behavior of each treatment were lowered by electron beam treatment (10 and 100 kGy) and grinding process. NFC films were prepared to investigate their mechanical properties. There were little changes in tensile properties of the NFC films.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.609-611
• /
• 1998

In this paper, a method for the efficient implementation of the control network for a distributed control system (DCS) is proposed. The proposed method focuses on the real-time property and the low networking cost of a control network. It suggests a new network architecture combining the IEEE 802.4 token-passing bus access method and the IEEE 802.3 physical layer. For this purpose, a new interface, a physical layer service translator is introduced. A control network using this method is implemented and applied to a DCS.

• Journal of the Korean Mathematical Society
• /
• v.31 no.3
• /
• pp.393-400
• /
• 1994

Subminifolds of Euclidean spaces have been studied by examining geodesics of the submanifolds viewed as curves of the ambient Euclidean spaces ([3], [7], [8], [9]). K.Sakamoto ([7]) studied submanifolds of Euclidean space whose geodesics are plane curves, which were called submanifolds with planar geodesics. And he completely calssified such submanifolds as either Blaschke manifolds or totally geodesic submanifolds. We now ask the following: If there is a point p of the given submanifold in Euclidean space such that every geodesic of the submanifold passing through p is a plane curve, how much can we say about the submanifold\ulcorner In the present paper, we study submanifolds of euclicean space with such property.

• Journal of information and communication convergence engineering
• /
• v.8 no.1
• /
• pp.13-18
• /
• 2010

The composite stock cutting problem is defined as allocating rectangular and irregular patterns onto a large composite stock sheet of finite dimensions in such a way that the resulting scrap will be minimized. In this paper, we introduce a novel approach to hybrid optimization algorithm called MGA in MPI (Message Passing Interface) environments. The proposed MGA combines the benefit of rapid convergence property of Mean Field Annealing and the effective genetic operations. This paper also proposes the efficient data structures for pattern related information.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.25 no.5
• /
• pp.856-867
• /
• 2001

The purpose of this study was to develop washable panties for elderly women of incontinence urine. We carried out a questionnaire survey in order to find out what are the inconvenience of incontinence. Also we analyse the properties of incontinence panties available in silver market. Then we did wearing test of the existing continence panties to 40 subjects. Having done the wearing test, it was clear that the composit and the size of the absorbing layers must be crucial points of the development of the prototype panty. The prototype was designed to improve absorbing speed as well as capability without sacrificing of wearing comfort. The developed prototype panty went through wearing test and property tests to assure the design. The results are as follows:- 1. Absorbing capability as a whole, quick absorbance at the moment of passing of urine, the touch of the cover layer after quick absorbance and deodorant property were improved than existing incontinence panties. 2. The size and the dimensions of each part, specially absorbing layers at the crotch area, were remarkably improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1419-1424
• /
• 2007

Centrifugal turbo blower is requested highly efficiency and low noise in FCEV, but the noise generated by this machine causes of the most serious problems in the NVH performance. In general, centrifugal turbo blower is dominated by mechanical noise and aerodynamic noise. Mechanical noise is generated by rotation of the bearing, misalignment and unbalance. And aerodynamic noise is generated by the strong intersection between the flow discharged from the impeller and the cut-off in the casing. The first object of this study is to comprehend a noise property of the blower through the noise test. And, second object is to bring up the method that can reduce blower noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.5
• /
• pp.516-523
• /
• 2008

Centrifugal turbo blower is requested highly efficiency and low noise in FCEV, but the noise generated by this machine causes of the most serious problems in the NVH performance. In general, centrifugal turbo blower is dominated by mechanical noise and aerodynamic noise. Mechanical noise is generated by rotation of the bearing, misalignment and unbalance. And aerodynamic noise is generated by the strong intersection between the flow discharged from the impeller and the cut-off in the casing. The first object of this study is to comprehend a noise property of the blower through the noise test. And, second object is to bring up the method that can reduce blower noise.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.550-553
• /
• 2003

This paper was shown water properly conversion and removal characteristic of escherichia coli for discharge tube with $ZrO_2$ beads. At the result of the removal characteristic experiments of escherichia coli using the discharge tube with $ZrO_2$ beads, because the electric field is also increased when input voltage is increased, the removal characteristic of escherichia coli was appeared relation connection to input voltage. And if a passing number of test water in discharge tube with $ZrO_2$ beads is increased, the removal ratio of escherichia coli is to be increased because passing number of electric field section is increased. And if diameter of $ZrO_2$ beads is increased, the removal time of escherichia coli is to be decreased because dielectric polalization of $ZrO_2$ beads. Also, the removal ratio of escherichia coli of the discharge tube with $ZrO_2$ beads. is appeared higher than the removal ratio of the discharge tube without $ZrO_2$ beads. And a salutation point of ozone and $H_2O_2$ generation density inner water was appeared near 60[min].

• International Journal of Highway Engineering
• /
• v.16 no.2
• /
• pp.119-129
• /
• 2014

PURPOSES : The purpose of this study is to develop the U-turn accident model at 4-legged signalized intersections in urban areas. METHODS : In order to analyze the characteristics of the accidents which are associated with U-turn operation at 4-legged signalized intersections in urban areas and develop an U-turn accident model by regression analysis, the tests of overdispersion and zero-inflation are conducted about the dependent variables of number of accidents and EPDO (Equivalent Property Damage Only). RESULTS : As their results, the Poisson model fits best for number of accident and the ZIP (Zero Inflated Poisson) fits best for EPOD, the variables of conflict traffic, width of opposing road, traffic passing speed are adopted as independent variable for both models. The variables of number of bus berths and rate of U-turn signal time at which the U-turn is permitted are adopted as independent variable only for EPDO. CONCLUSIONS : These study results suggest that U-turn would be permitted at the intersection where the width of opposing road is wider than 11.9 meters, the passing vehicle speed is not high and U-turn operation is not hindered by the buses stopping at bus stops.