• 한국산림과학회지
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• 제94권2호통권159호
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• pp.82-89
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• 2005

The purpose of this paper is to investigate index numbers by conducting various comparisons among the widely used index formulas. The comparison is considered in three ways; 1) divergences in the magnitudes of index numbers due to the use of different formulas (Laspeyres, Paasche, Fisher, and Tornqvist); 2) the effect of selection of base year (fixed-year base vs. chain-type); 3) the degree of approximation of indirect to direct quantity index. The empirical application is to sawmills and planing mills industry of U.S. using a national time series data covering years of 1948-2000. The results show that the differences between Laspeyres and Paasche index can be substantial in some cases while the difference between Fisher and Tornqvist index is minimal. We also confirm that the selection of base year can cause significant divergences, especially when the variables undergo rapid price or quantity changes over time. We find that indirect quantity index approximates direct quantity index reasonably well in U.S. sawmill industry.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.974-979
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• 2008

The purpose of this study was to evaluate the effect of vegetation on the cutting slope applied by vegetation system in the whole land. The engineering characteristics of slopes were investigated using the face mapping and physical tests. From the statistical methods, a relationship between a geologic stratum and degree of covering was independent. Therefore, the afforestation of slope was affected more by condition of vegetation as direction and opening of joints, and a topsoil state than by conventional classification of layer. It was concluded that the adjustable vegetation on the slope considering condition of geometric shape of slope, joint data and spontaneous type could make useful early afforestation.

• Journal of Chest Surgery
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• 제55권3호
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• pp.246-249
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• 2022

Recurrent pectus excavatum (PE) after a Ravitch operation is not uncommon. Extensive costal cartilage resection from the previous Ravitch procedure can lead to an irregular, unstable chest wall depressions with a varying degree of deformity. The optimal approach to cover the chest wall defect and remodel the deformity, remains unknown. We report the case of a 27-year-old woman seeking surgery for the third time for recurrent PE. The patient presented with 2-time recurrent pectus excavatum following a failed Ravitch procedure and subsequent pectus bar repair. The entire chest wall reconstruction and remodeling entailed covering the chest wall defect with 2 titanium plates across both sides of the rib cage, and lifting and fixing the depressed chest wall with 2 parallel pectus bars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.237-242
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• 1998

Covering mortar as a filter for permeable polymer concrete is necessary for good permeability from filtration continuously. Therefore, this paper is intended as an evaluation of the mechanical properties and permeability of permeable polymer concrete covered with polymer mortar as a filter. An optimum permeable polymer concrete is selected in various mix proportions, and three different polymer mortars were cast immediately following on the casting of the base permeable polymer concrete. And they are tested for compressive and flexural strengths, adhesion in tension, hardening shrinkage and permeability . From the test results, binder and filler contents in mix proportions had a great influence on the permeability of polymer concretes. The mechanical properties of permeable polymer concretes covered with polymer mortars using crushed stone are superior to other filters, and hardening shrinkage is the smallest in filters. It is apparent that adhesion between the base permeable polymer concrete and polymer mortar is affected by the degree of hardening shrinkage. From this study, proper mix proportions can be recommended in the consideration of properties of the permeable polymer concrete.

• 한국정밀공학회지
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• 제17권3호
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• pp.158-164
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• 2000

In recent year, desire and request fer micro automation are growing rapidly covering the whole range of the industry. This has been caused mainly by request of more accurate manufacturing process due to a higher density of integrated circuits in semiconductor industry. This paper presents a six d.o.f fine motion stage using magnetic levitation technique, which is one of actuating techniques that have the potential for achieving such a micro motion. There is no limit in motion resolution theoretically that the magnetically levitated part over a fixed stator can realize. In addition, it Is possible to manipulate the position and the force of the moving part at the same time. Then, the magnetic levitation technique is chosen into the actuating method. However, we discuss issues of design, kinematics, dynamics, and control of the proposed system. And a few experimental results fur step input are given.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1248-1256
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• 2020

In this study, the polyurethane resin was synthesized by applying PTMG and DMBA of different composition ratios for the synthesis of water-dispersible polyurethane used in wound coating resin. The varying properties of the synthesized water-dispersible polyurethane were measured through tensile strength, elongation, and abrasion resistance analysis. As for the tensile strength measurement result according to the PTMG content, the sample with the highest reaction molar ratio was measured as 1.08 kgf/mm2 and the elongation was measured as 520%. As for the tensile strength result according to the DMBA content, the sample with the highest reaction molar ratio was measured as 0.51 kgf/mm2, and the elongation was measured as 435%. The degree of surface destruction by the abrasion resistance measurement was visually confirmed through SEM.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2005년도 추계학술대회 및 정기총회
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• pp.409-413
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• 2005

The logical analysis of data(LAD) is an effective Boolean-logic based data mining tool. A critical step in analyzing data by LAD is the pattern generation stage where useful knowledge and hidden structural information in data is discovered in the form of patterns. A conventional method for pattern generation in LAD is based on term enumeration that renders the generation of higher degree patterns practically impossible. In this paper, we present a new optimization-based pattern generation methodology and propose two mathematical programming medels, a mixed 0-1 integer and linear programming(MILP) formulation and a well-studied set covering problem(SCP) formulation for the generation of optimal and heuristic patterns, respectively. With benchmark datasets, we demonstrate the effectiveness of our models by automatically generating with much ease patterns of high complexity that cannot be generated with the conventional approach.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.1020-1025
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• 2005

The set covering(SC) problem has many practical application of modeling not only real world problems in civilian but also in military. In this paper we study optimal allocation model for maximizing utility of consolidating old fashioned and new air defense weapon system like Patriot missile and develop the new computational algorithm for the SC problem by using simulated annealing(SA) algorithm. This study examines three different methods: 1) simulated annealing(SA); 2) accelerated simulated annealing(ASA); and 3) selection by effectiveness degree(SED) with SA. The SED is adopted as an enhanced SA algorithm that the neighboring solutions could be generated only in possible optimal feasible region at the PERTURB function. Furthermore, we perform various experiments for both a reduced and an extended scale sized situations depending on the number of customers(protective objective), service(air defense), facilities(air defense artillery), threat, candidate locations, and azimuth angles of Patriot missile. Our experiment shows that the SED obtains the best results than others.

• 한국환경보건학회지
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• 제9권2호
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• pp.55-65
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• 1983

This survey was carried out to investigate the pattern of taking psychotropic drugs for 618 cases who visited 48 drugstores located as such four types of areas as business sections, gay quarters, residential sections and quasi-industrial areas from May, 1982 to March, 1983. The results are summarized as follows: I. The age distribution: The age group of 20-29 showed the highest distribution covering 35.6% as 220 out of 618 cases. The age groups of thirties and forties covered 23.0% and 19.0% respectively. The sex ratio was estimated as 1:1.86. 2. The occupational distribution: The unemployees composed the largest portion covering 53.7% as 332 out of 618. Above all the class of the housewives was 32.7%. 3. The marital status: The degree of distribution was higher on the sides of the group of married people than that of single and its percentage was 30.1. 4. The educational level: Most of the people who purchased the drugs had no knowledge of the effect of the drugs, and they covered 80.9%. 5. As for the motives, the twenties took psychotropic drugs in order to relief insomnia and that was the biggest major motive at the portion of 59.1%, 130 out of 618. 6. The age group of twenties who took the drugs for about 6 months showed the highest percentage of 52.7%. 7. The highest distribution appeared in the case that takes one or two tablets a day for less than 6 months. 8. The dosage distribution by the number of times taking the drugs The group of people that took the drugs more than 3 to 4 tablets a day as the number of 1 to 3 times covered 41.7\ulcorner0 of 187. 9. The most favorite psychotropic drugs: Lorazepam was showed to be the most favorite drugs by either male or female covered 50.9o70, 54.2\ulcornero respectively. 10. The motives of selecting drugs: The optional motives of selecting psychotropic drugs were showed 269 (43.5%) out of 618 cases that chose the drugs for themselves.

• 대한치과보철학회지
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• 제39권4호
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• pp.336-350
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• 2001

The purpose of this study was to investigate corrosion tendency and to compare corrosion resistance of three dental magnetic attachments and its keeper alloy by coercive, electrochemical method. By using petentiodynamic polarization technique, magnetic elements and its keeper alloy of Magfit EX600 system(MF, MFK), Dyna ES regular system(DN, DNK) and Shiner SR magnet system(SR, SRK) were corroded electrochemically in 0.9% NaCl electrolytic solution. Open-circuit potential and anodic polarization curve was measured with Potentiostat(model 273 EG&E) and polarization curve was created by current density per square area following scanning of increased series of voltage in the rate of 1.0mV per second. Before and after electrochemical corrosion, the surface roughness test was done. Thereafter the change of mean surface roughness value(Ra) and mean peak value(Rt) of surface roughness was compared one another. In order to observe the corroded surface of each specimen, metallurgical light microscopic(${\times}37.5$) and scanning electron microscopic view(SEM ${\times}100$) was taken and compared one another. Conclusion is followings. 1. All of six covering metal of dental magnetic attachments and its keeper alloy were corroded in various degree after electrochemical corrosion. 2. The corrosion resistance of which used in this experiment is the following in high order; DNK, MFK, DN, MF, SRK and SR. 3. Especially Shiner magnet system and its keeper alloy were more severely corroded after electrochemical corrosion and the change of Ra Rt value were more increased than others. 4 Metallurgical and scanning electron microscopic view showed the pitting corrosion tendency of all experimental alloy but DNK and SR. 5. Covering metal of magnet was more corroded than its keeper alloy.