• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.691-698
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• 2015

Inertial Navigation Systems (INS) are widely used as the main navigation device for aircraft. To get the initial attitude, the INS requires the initial alignment before navigation starts. An aircraft also needs an engine test procedure that causes some vibrations before flight. An INS can't be aligned in a vibration environment so the initial alignment is performed before the aircraft engine test. Therefore, the initial alignment time of an INS has been a major factor in limiting an aircraft's takeoff response time. In this paper, we designed an initial alignment algorithm that can be executed even in disturbances such as aircraft run-up. We demonstrated verification of the algorithm that is embedded on the real INS and testing methods to evaluate the alignment of the INS. We also analyzed the test results of the proposed initial alignment algorithm that is performed during a real aircraft run-up.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.17-20
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• 2015

The physical effects of H-plasma treatment on ZnO thin film have been studied using photoluminescence(PL) spectroscopy. Four characteristic peaks have been identified: (i) $D^0X$ peak (neutral donor-bound exciton), showing relatively small integrated intensity after H-plasma treatment, indicates that H-plasma passivates the neutral donors in ZnO at low temperatures. The rapid decrease in the integrated intensity of the peak as the temperature goes up is considered to be due to the ionization of neutral donors. (ii) H-related complex-bound exciton peak appears at the low temperatures (10 K~80 K) after H-plasma treatment, showing the same thermal evolution as $D^0X$ peak. (iii) FX (free exciton) peak starts to show up at 60 K and grows more and more as the temperature goes up, which is considered to be related to the increase in free electron concentration in the film. (iv) violet band is intensified after H-plasma, which means more defects and impurities are generated by H-plasma process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.153-162
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• 1997

M/G/1 queueing system is one of the most widely used one to model the real system. When operating a real systems, since it often takes cost, some control policies that change the operation scheme are adopted. In particular, the N-policy is the most popular among many control policies. Almost all researches on queueing system are based on the assumption that the arrival rates of customers into the queueing system is constant, In this paper, we consider the M/G/1 queueing system whose arrival rate varies according to the servers status : idle, set-up and busy states. For this study, we construct the steady state equations of queue lengths by means of the supplementary variable method, and derive the PGF(probability generating function) of them. The L-S-T(Laplace Stieltjes transform) of waiting time and average waiting time are also presented. We also develop an algorithm to find the optimal N-value from which the server starts his set-up. An analysis on the performance measures to minimize total operation cost of queueing system is included. We finally investigate the behavior of system operation cost as the optimal N and arrival rate change by a numerical study.

• Journal of Family Resource Management and Policy Review
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• v.5 no.1
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• pp.61-78
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• 2001

This study intends to provide the groundwork for an establishment of women entrepreneur policy and the guidelines for start-up of women-owned business. The findings of the study are as follows; Women starts business for a financial reasons and this makes up 26 percent, which ranked the highest of respondents motive for starting up a business. The double labor - due 새 the practice of housework and running a business simultaneously - forms 19.6 percent of the bottleneck in operating business. In addition, the worst financial strain, 43 percent, occurred during the business preparatory period. As the entrepreneurship is higher, they are more backed up with support in education and training. In addition, annual net profit of business operated by the older age group is relatively greater. The firm performance is greater as she holds a higher academic degree. As the goal of annual net profit is higher that is set up before the start-up, the net gain turns out to be greater in actual operation, thus resulting in greater effects. The study shows that when they received economic aid, the initial capital had been greatly affected The younger age group makes up the higher percentage of support in education and training. After considering all the findings collectively, the conclusions are as follows; First, the firm performance is affected by the entrepreneurship, schooling, age, and the goal of the female entrepreneur. Second, a support in education and economic does not have a direct effect on the firm performance. However, the study reveals that the entrepreneurship of those who received educational support is higher than that of those who did not. Third, the in-depth interview reveals the facts that how they had been brought up and how the role of the family had a significant effect on their management of business.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.106-111
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• 2015

Since most reference voltage generator circuits have bi-stable characteristics, it is important to employ a proper start-up circuit to operate a reference generator in the desired state. In this paper, we propose a start-up circuit for a low voltage reference generator. This start-up circuit determines the state of the circuit reliably by measuring the current drawn by BJTs in the circuit, which is well-defined in the desired state. To measure the current using CMOS-compatible devices only, a comparator with an internal offset voltage is used. The reliability of the proposed circuit is confirmed by Monte-Carlo simulations of the start-up operation, which show that, with the proposed start-up circuit, the low voltage reference generator starts reliably with supply voltages over 850mV even in the presence of device mismatches.

• Fashion & Textile Research Journal
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• v.19 no.3
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• pp.289-295
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• 2017

This study aims to develop clothing sales forecast system using weather information. As the annual temperature variation affects changes in daily sales of seasonal clothes, sales period can be predicted growth, peak and decline period by changes of temperature. From this perspective, we analyzed the correlation between temperature and sales. Moving average method was applied in order to indicate long-term trend of temperature and sales changes. 7-day moving average temperature at the start/end points of the growth, peak, and decline period of S/S clothing sales was calculated as a reference temperature for sales forecast. According to the 2013 data analysis results, when 7-day moving average temperature value becomes $4^{\circ}C$ or higher, the growth period of S/S clothing sales starts. The peak period of S/S clothing sales starts at $17^{\circ}C$, up to the highest temperature. When temperature drops below $21^{\circ}C$ after the peak temperature, the decline period of S/S clothing sales is over. The reference temperature was applied to 2014 temperature data to forecast sales period. Through comparing the forecasted sales periods with the actual sales data, validity of the sales forecast system has been verified. Finally this study proposes 'clothing sales forecast system using weather information' as the method of clothing sales forecast.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.3
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• pp.387-394
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• 1994

Journal of the Korean Society of Clothing and Textiles Vol. 18, No. 3 (1994) p. 387∼394 In this study, the restriction of slacks (blue jean) versus box pleats skirt was investigated, from the view point of peripheral blood flow at the toe according to motion variation and E.M.G. analysis of leg muscles after walking on the flat or going up and down stairways. Besides, the pressure of slacks on the lower extrimity was measured statically and dynamically. The main results were summerized as follows; 1. The clothing pressure applied by slacks was; each one of thigh and lower leg was 18.2 g/ cm2 and 22.1 g/cm2 in upright, 63.4 g/cm2 and 26.6 g/cm2 in sitting on the chair, on both sides of thigh and lower leg 272.0 g/cm2 over in squatting. 2. When the motion starts from upright, the dynamic clothing pressure reach their peak before the motions end. When the motion ends and the body comes to a still condition, the clothing pressure grow lower and indicate a constant value. but when the body starts moving again to return to upright, the pressures once grow higher and go to zero value after reaching the peak. The pressure on the knee show much greater than those on the hip. This can be because these pressures depend on the degree of skin stretching motion and of its curvature. 3. The surface E.M.G. in leg muscles M. rectus femoris and M. gastrocnemius were recoreded. In the case of wearing slacks, two muscles were activated much more than wearing skirt. 4. The peripheral blood flow at the toe by wearing slacks was lower than wearing skirt. Also the case when squatting, the peripheral blood flow at the toe was low.

• Steel and Composite Structures
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• v.1 no.4
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• pp.427-440
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• 2001

The growing use of unprotected or partially protected steelwork in buildings has caused a lively debate regarding the safety of this form of construction. A good deal of recent research has indicated that steel members have a substantial inherent ability to resist fire so that additional fire protection can be either reduced or eliminated completely. A performance based philosophy also extends the study into the effect of structural continuity and the performance of the whole structural totality. As part of the structural system, thermal expansion during the heating phase or contraction during the cooling phase in most beams is likely to be restrained by adjacent parts of the whole system or sub-frame assembly due to compartmentation. This has not been properly addressed before. This paper describes an experimental programme in which unprotected steel beams were tested under load while it is restrained between two columns and additional horizontal restraints with particular concern on the effect of catenary action in the beams when subjected to large deflection at very high temperature. This paper also presents a three-dimensional mathematical modelling, based on the finite element method, of the series of fire tests on the part-frame. The complete analysis starts with an evaluation of temperature distribution in the structure at various time levels. It is followed by a detail 3-D finite element analysis on its structural response as a result of the changing temperature distribution. The principal part of the analysis makes use of an existing finite element package FEAST. The effect of columns being fire-protected and the beam being axially restrained has been modelled adequately in terms of their thermal and structural responses. The consequence of the beam being restrained is that the axial force in the restrained beam starts as a compression, which increases gradually up to a point when the material has deteriorated to such a level that the beam deflects excessively. The axial compression force drops rapidly and changes into a tension force leading to a catenary action, which slows down the beam deflection from running away. Design engineers will be benefited with the consideration of the catenary action.

• Journal of Acupuncture Research
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• v.17 no.2
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• pp.85-93
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• 2000

We came to the conclusion after considering all the information from many kinds of books on the circulation courses, cross-link points, functions and the symptoms of disease of Chongmai. The results were as follows : 1. The Chongmai that starts from a Uterus flows to Dazhu through the inside of vertebra after joining Renmai and Duimai at Huiyin. The Chongmais up-line that comes out from Qichong into a surface of body arrives and is scattered at a chest through an abdomen. One strand of them goes upward again and is connected to a throat and lips area. After coming out from Qichong, separated down-line is divided into two parts when it arrives a inner part of a heel through the inner part of a leg. One is for an instep, the other is for the sole of a foot. 2. We call it "Sea of Twelve Meridians" or "Meridian's Sea". Because Chongmai controls all of Meridian by acquired "Basic energy" as getting Stomach's energy, Kidney's energy and air-energy, and there are responsible of physiological phenomenon control. And also we name it "Sea of Blood", because it starts from and provides a nutrition to Uterus. 3. All of these four Meridian such as Renmai, Kidney Meridian, Stomach Meridian and Spleen Meridian are ones that flow around the part of a chest and an abdomen. Chongmai makes energy and blood circulation of a chest and an abdomen be stronger and be controlled. Therefore it makes viscera, bowels and body surface be warm and given a nutrition. So Chongmai becomes "Sea of Viscera and Bowels". 4. Chongmai provides a nutrition for ligament and muscle and makes legs get warm as making energy and blood circulate from head to foot. If Chongmai is energetic, hair is completely easy to grow. 5. To see in pathological phase, Chongmais failure or weakness causes like a chest pain, stomachache, heart attack, a menstrual irregularity and sterility and so on. And also if Chongmai is damaged, it happens that giving a nutrition for lips area is stopped, and then mustache doesn't grow any more.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.2
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• pp.121-128
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• 1996

A direct cooling equipment for hydrogen liquefaction has been developed and tested. A direct cooling equipment consists of a liquefaction vessel, a radiation shield, a cryostat and a GM refrigerator. The cool-down and warm-up characteristics of the liquefaction apparatus have been investigated in detail. It is found that the hydrogen starts to be liquefied in the liquefaction vessel after 45 minutes of cool-down. The cool-down and warm-up tests of helium gas are also performed. The cool-down and warm-up characteristics of helium gas are found to be very different from those of hydrogen gas, since helium is not liquefied under the present operating conditions. When the liquefaction vessel is evacuated, natural convection phenomena of charged gas in liquefaction vessel can be removed. It is seen that the cool-down time of liquefaction vessel is substantially increased in vacuum environment.