• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.373-378
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• 1998

A method to construct a memoryless feedback law for systems with multiple time-delays in the states is proposed. As a plant model, a differential-difference equation with multiple delayed terms is introduced, A stabilizability condition by memoryless feedback is presented. A feedback gain is calculated with a solution of a finite dimensional Riccati equation. It is shown that the resulting closed loop system is asymptotically stable, and moreover, it is a linear quadratic regulator for some cost functional. An alternative stabilizability condition which is easier to check is given.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.665-666
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• 2004

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.107-115
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• 2017

In this study, the surface check reduction effect of preservative-treated Korean larch round-wood was investigated by applying three physical treatments, such as incising, kerfing, and kiln-drying. Moreover, the possibility of long-term service life was also checked by comparing the depth of surface check and the penetration depth of preservative. A rapid gradient of wood moisture content between surface and center causes a surface check. Thus, the effect of reducing surface check was carried out at the lowest equilibrium moisture content (EMC) condition, temperature ($2^{\circ}C$), humidity (44.6%), in outdoor locations in Korea until the test specimens reach to the 8.6% EMC. As a result, the preservative-treated specimens without incising, kerfing, kiln-drying (Type C) could not ensure the long-term service life due to a large surface check. Because the surface check depth of all specimens was deeper than the penetration depth of preservative. In case of the incising treated specimens (Type I), 80% of them, the depth of surface check was not deeper than the penetration depth of preservative. However, when a kerfing was additionally treated (Type B), a possibility of happening deeper surface check than penetration depth of preservative was increased rather than Type I.

• Progress in Medical Physics
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• v.28 no.4
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• pp.181-189
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• 2017

The conventional delivery quality assurance (DQA) process for RapidArc (Varian Medical Systems, Palo Alto, USA), has the limitation that it measures and analyzes the dose in a phantom material and cannot analyze the dosimetric changes under the motional organ condition. In this study, a DQA method was designed to overcome the limitations of the conventional DQA process for internal target volume (ITV) based RapidArc. The dynamic DQA measurement device was designed with a moving phantom that can simulate variable target motions. The dose distribution in the real volume of the target and organ-at-risk (OAR)s were reconstructed using 3DVH with the ArcCHECK (SunNuclear, Melbourne, USA) measurement data under the dynamic condition. A total of 10 ITV-based RapidArc plans for liver-cancer patients were analyzed with the designed dynamic DQA process. The average pass rate of gamma evaluation was $81.55{\pm}9.48%$ when the DQA dose was measured in the respiratory moving condition of the patient. Appropriate method was applied to correct the effect of moving phantom structures in the dose calculation, and DVH data of the real volume of target and OARs were created with the recalculated dose by the 3DVH program. We confirmed the valid dose coverage of a real target volume in the ITV-based RapidArc. The variable difference of the DVH of the OARs showed that dose variation can occur differently according to the location, shape, size and motion range of the target. The DQA process devised in this study can effectively evaluate the DVH of the real volume of the target and OARs in a respiratory moving condition in addition to the simple verification of the accuracy of the treatment machine. This can be helpful to predict the prognosis of treatment by the accurate dose analysis in the real target and OARs.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.189-197
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• 2008

Using a 5 year(2003 to 2007) pavement condition survey data from the highway pavement management system(HPMS), the roughness of the bridge deck pavement was analyzed. Based on the result of this analysis, this study tried to identify the factors affecting the deterioration of the bridge deck pavement condition. The data from HPMS indicates that the roughness of the bridge deck pavement is worse than that of the general pavement on the roadbed. The worse roughness of the bridge deck pavement is caused by the settlement of approach slab as well as the surface distress on the bridge deck pavement. In order to improve effectively the roughness of the bridge deck pavement, a management system was established in which not only the regular automated pavement condition survey to check the distress of surface of the bridge deck pavement was adopted but an automated surface profiler to check the degree of settlement of approach slab was applied.

• Journal of the Korean Society of Fashion and Beauty
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• v.4 no.3 s.9
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• pp.18-24
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• 2006

Hair is the part of body which expresses man into more manlike. When we create some artworks, we need the most suitable material for the artworks. Similarity, the healthy scalp hair condition and treatment are required to keep our hair clean and healthy. And the improper condition of scalp hair prohibits our hair from normal growing, proceeds the alopecia(loss of hair) and double our physical and mental stresses. The necessity of health treatment of scalp hair which was damaged by frequent permanent hair wave and hair coloring is on the rise. This study will present how to control and treat the scalp hair and will check how we feel about the necessity of scalp hair treatment. This study finally shows that people think their scalp hair conditions are not normal and chemically treated hair in spite of their natural hair. However, most people think that the scalp hair treatment is very useful to their hair and this result enables us to predict the future market of the scalp hair treatment business will be growing day by day. We need to study further not only scalp hair treatment but also prevention stage in order to keep the healthy hair and will check how we feel about the necessity of scalp hair treatment.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.122-130
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• 2014

Attrition characteristics of WGS catalysts for pre-combustion $ CO_2$ capture were investigated to check attrition loss of those catalysts, to check change of particle size distribution during attrition tests, and to determine solid circulation direction of WGS catalysts in a SEWGS system. The cumulative attrition losses of two catalysts increased with increasing time. However, attrition loss under humidified condition was lower than that under non-humidified condition case for long-term attrition tests. Between two catalysts, attrition loss of PC-29 catalyst was higher than that of commercial catalyst for long-term attrition tests. However, the commercial catalyst generated much more fines than PC-29 catalyst during attrition. Therefore, we conclude that the PC-29 catalyst is more suitable for fluidized bed operation if we take into account the separation efficiency of cyclone. Based on the results from the tests for the effect of humidity on the attrition loss, we selected solid circulation direction from SEWGS reactor to regeneration reactor because the SEWGS reactor contains more water vapor than regeneration reactor.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.149-154
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• 2009

By increasing people's average life span, interest for health is highly growing. According to hoping to check their body condition, people have a medical checkup periodically to check their condition. But, they can prevent disease or are able to make a health care through checking people's pulse or blood pressure. In this paper, two different pulse measurement systems were developed, one system using a photosensor which is able to measure transmissivity's change through blood volume and another system using a piezo-electric sensor which can measure pulse when it measures radial artery's pressure in the wrist are realized. We compared two systems each other.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.2
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• pp.19-29
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• 2013

Objectives : The main purpose of this study is to investigate the efficiency of Gagamchengyoung-tang (Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and examine the febrile tendency in the alopecia patients Methods : Of the patients who have visited Balmers Korean Medicine clinic for alopecia from December first 2012 to December 31st 2012, we enrolled 30 patients and performed heat and cold diagnosis, examine scalp and check hair density. We administrated Gagamchengyoung-tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and acupuncture to all patients. The effect was assessed by scalp condition and hair density Results : The scalp disorder index decreased and hair density increased in alopecia patients with febrile tendency Conclusions : All patients had febrile tendency and Gagamchengyoung-Tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) can be effective in the scalp disorder and alopecia.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.87-96
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• 1995

It is only three(3) years since we applied brackets for scaffolding in the construction area. Unfortunately, there is no structural criteria on how to install those in the site so far, despite the fact that those brackets have been applied into the site by the firms already. It is shown that resistant capacity of each bracket type has been investigated, analyzed from this experimental study. Accident-concerning data on construction site analyzed by the Ministry of Labor, show temporary structure involves 18.6% of the total industrial accident, which the accidents from scafold-supporting brackets have rate of 42.5% of the ones occurred from the temporary structures. There are two main aspects to be observed : one is how much resistant capacity the brackets have themselves, the other is how exactly to install those without eccentricity. But practically, nobody does check of this bolt-installing conditions in the site and no check of tightening level of nut because there is no available tool to check torque amount for this kind of nut. We just have to rely on scaffolders experience of this tightening. This experiment involves just this variable of tightness at site. Eventually this insufficient tightness causes to collapse those scaffolding structures. The bracket might have less the one than its original capacity due to this insufficient tightness. Three(3) times of PIVOT tests show that fractured condition of two(2) row brackets has occurred mostly at lower bolt due to shear force. Therefore, tightness of bracket-installing bolt, tensile strength of the bolt, shear strength of the bolt, loading condition with equal two point or inequal two point loads, are mainly investigated as variables in this study.