• 한국기계가공학회지
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• 제18권4호
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• pp.16-25
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• 2019

Recently, due to labor shortages in rural areas within South Korea, the demand for upland-field machinery is growing. In addition, there is a lack of development of systematic performance testing of upland-field machinery. Thus, this study examined structural safety and drawbar pull based on soil properties, as a first step for systematic performance testing on the test bed. First, the properties of soil samples from 10 spots within the experimental site were examined. Second, the strain was measured and converted into stress on 8 points of an onion harvester that are likely to fail. More specifically, the chosen parts are linked to the power, along with the drawbar pull, using a 6-component load cell equipped between the tractor and the onion harvester. The water content of the soil ranged between 5.7%-7.5%, and the strength between 250-1171 kPa. The test soil was subsequently classified into loam soil based on the size distribution ratio of the sieved soil. The onion harvester can be considered as structurally safe based on the derived safety factor and the drawbar pull of 115-1194 kgf, according to the working speed based on agricultural fieldwork.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.462-466
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• 2008

This paper proposes a stable gain scheduling method of linear time invariant controllers for tracking servo system. In order to read and write the data on the optical disc, the pick-up head should be moved to the exact track quickly and follow the track immediately. Two different controllers are used for each moving and track-following. In pull-in period, a transition period from moving to track-following, the head might slip and miss the target track. This brings on another searching process and increases the total time. One way to avoid slipping is to extend the bandwidth of the track-following controller. But, extending the bandwidth could degrade the following performance. More prevalent way is to use one more controller in this pull-in period and switch to the following controller. In general, however, switching or scheduling of stable controllers cannot guarantee the stability. This paper suggests an scheduling method guaranteeing the overall stability not only in a generalized form but also in special form for SISO system. The sufficient condition is derived from the fact that Q factor of a stable controller should be stay in $RH_{\infty}$ space. In the experiment, the proposed method shows better performance than the switching method such as shorter time and lower current consumption.

• Journal of Information Technology Applications and Management
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• 제27권5호
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• pp.49-68
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• 2020

The Push-Pull-Mooring (PPM) model employ to explore the factors that affect the switching intention of mobile game players by analyzing the online survey data of 240 mobile game players in China. From the perspective of PPM model, Dissatisfaction with the current mobile game can promote players to leave the current mobile game, and other more attractive mobile games can pull players out of the current mobile game. As a mooring factor, habit can affect players' switching decisions. Players who have formed strong habits in current mobile games are more likely to resist or ignore the attractiveness of other mobile games and stay in the current mobile games rather than migrate to other mobile games. Another result shows that the more dissatisfied with the current mobile game, the higher the quality of alternative (relative challenge) mobile game, and the lower the investment size in the current mobile game, the more reluctant the players are to continue to maintain the relationship with the current mobile game. The higher the player's commitment to the current mobile game, the more likely it is to maintain the relationship with the current mobile game. The empirical results show that the framework of this study is highly consistent with the results of PPM model, and confirming that they can well apply to mobile game situations.

• 한국농공학회논문집
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• 제63권3호
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• pp.27-33
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• 2021

Reclaimed land was mainly used as agricultural land for rice production. As a higher value-added business in the agriculture has recently been activated, green houses are being constructed. In case of green house construction on the reclaimed land, it is generally soft ground with high soil water content, so it is important to design the foundation for greenhouse construction. The object of this study, a pull-out test was conducted to derive the base line data of the wooden pile foundation when constructing a green house. To reproduce the actual site, 30% of soil saturation and 70% of soil saturation were created in the soil box. Groove number and depth were set as design factors of the wooden pile, and a pull-out test was conducted. As a result of the test, pull resistance increased as the number of grooves increased, pull-out resistance according to groove depth was different according to soil saturation. Also, after the experiment, we want to compare the set-up effects over time.

• 보건행정학회지
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• 제2권2호
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• pp.221-237
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• 1992

The reasons for cost inflation in medical insurance expenditure are classified into demand pull inflation and cost push inflation. The former includes increase in the number of beneficiaries and utilization rate, while the latter includes increase in medical insurance fee and the charges per case. This study was conducted to analyze sources of increases of expenditure in medical insurance demonstration area by the period of 1982-1987 which was earlier than national health insurance and the period of national health insurance(1988-1990). The major findings were as follows: Medical expenditure in these areas increased by 9.4%(15.1%) annually between 1982 and 1990 on the basis of costant price(current price) and for this period, the yearly average increasing rate of expenses for outpatient care[10.5%(15.8%)] was higher than that of inpatient care [7.3%(12.6%)]. Medical expenditure increased by 6.3%(8.9%) annually between 1982 and 1987, the period of medical insurance demonstration, while it increased by 10.7%(18.9%) after implementing national health insurance(1988-1990). Medical expenditure increased by 35.9%(45.9%) between 1982 and 1987. Of this increase, 115.2%(92.1%) was attributable to the increase in the frequencies of utilization per beneficiary and 61.0%(68.1%) was due to the increase in the charges per case, but the expenditure decreased by 76.2%(60.2%) due to the reduction in the number of beneficiaries. Beteen 1988 and 1990, the period of national health insurance, medical expenditure increased by 21.2%(41.4%). Of this increase, 87.5%(46.4%) was attributable to the increase in the frequencies of utilization per beneficiary and 52.4%(73.4%) was due to the increase in the charges per case, and of the increase in the charges per case, 69.6%(40.8%) was attributable to the increase in the days of visit per case. Medical expenses per person in these areas increased by 78.2%(89.0%) between 1982 and 1987. Of this increase, 76.6%(69.1%) was attributable to the increase in the frequencies of utilization per beneficiary and 23.4%(30.9%) was due to the increase in the charges per case. For this period, demand-pull factor was the major cause of the increase in medical expenses and the expenses per treatment day was the major attributable factor in cost-push inflation. Betwee 1988 and 1990, medical expenditure per person increased by 31.2%(53.1%). Of this increase, 60.8%(37.2%) was attributable to the demand-pull factor and 39.2%(62.8%) was due to the increase in the charges per case which was one of cost-push factors. In current price, the attributalbe rate of the charges per case which was one of cost-push factors was higher than that of utilization rate in the period of national health insurance as compared to the period of medical insurance demonstration. In consideration of above findings, demand-pull factor led the increase in medical expenditure between 1982 and 1987, the period of medical insurance medel trial, but after implementing national health insurance, the attributable rate of cost-push factor was increasing gradually. Thus we may conclude that for medical cost containment, it is requested to examine the new reimbursement method to control cost-push factor and service-intensity factor.

• 생명과학회지
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• 제23권11호
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• pp.1311-1316
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• 2013

hnRNP L은 pre-mRNA에 결합하는 단백질들 중에서 핵심이 되는 단백질이다. hnRNP L은 양이 아주 많은 핵 단백질로서 핵과 세포질을 왕복하는 특성을 지니고 있다. 이 단백질은 염색질 변형(chromatin modification), pre-mRNA 스플라이싱, 인트론이 없는 유전자들에서 유래한 mRNA들의 세포질로의 반출(export), IRES-매개성 번역, mRNA의 안정성 조절, 정자형성과정 등, 세포 내의 여러 가지 과정에 관여하고 있는 것으로 알려져 있다. 이 논문에서는 hnRNP L과 결합하는 세포 내 단백질을 찾아내기 위하여 사람의 간세포 cDNA library를 사용하여 이스트 two-hybrid 탐색 실험을 수행하였다. 그 결과 사람의 간세포에서 IGFBP-4가 hnRNP L과 상호결합하는 새로운 파트너라는 것을 발견하였다. 본 연구를 통하여 hnRNP L이 이스트 two-hybrid 시스템에서 IGFBP-4와 특이적으로 상호 결합한다는 것을 처음으로 발견하였다. 본 연구에서는 또한 이스트 two-hybrid 시스템에서 hnRNP L이 IGFBP-4와 상호결합한다는 점을 in vitro pull-down 실험을 통하여 재확인하였다.

• KIEAE Journal
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• 제13권1호
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• pp.141-150
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• 2013

As longevity of human-beings is extended and the population of aged people increases, diverse issues related with the aged people are presented. The neighborhood space for the aged people is required to be designed based upon the understanding of such difficulties of the elderly and the public outdoor environment is an important environmental resource that can enhance the quality of life and promote the health of the elderly in underprivileged area without burdening them economically. This study aims to research the daily life of the elderly in underprivileged urban area and their utilization styles of outdoor environments in order to find out the push factors and pull factors that induce the aged people to use the outdoor environments. For this purpose, this study carried out an interview survey upon 69 elderly residents and surveyed on 363 elderly residents of low income class who are aged 60 and over and living in decaying area in Jeonju. For the analysis of the collected data, a qualitative and a quantitative analysis were accomplished. As results of study, the elderly in underprivileged area use such outdoor environments as resting facilities, exercise equipment, parks, farming gardens and waterfronts, and the push factors for them to use the outdoor environments were sordid indoor spaces, sense of isolation or loneliness, and the desire for maintaining good health. And the pull factors for them to use the outdoor environments were natural factors, opportunities for social interactions, space for exercise. The obstacles that hinder the elderly in using outdoor environments were the bad health of the elderly, lack of facilities, accessibility and weather conditions. Thus, the results of this study are expected to provide basic data for designing the outdoor environments to promote the health of the elderly in urban underprivileged area and to relieve the burdensome problems related with ageing societies.

• 한국건축시공학회지
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• 제22권2호
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• pp.149-160
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• 2022

본 연구에서는 국내에서 생산되는 목재와 접착제를 활용한 Glued-in rod 접합부의 인발성능을 평가하고자 접착제의 종류, 철근의 매입깊이 및 매입방향을 고려한 인발성능 실험연구를 수행하였다. 실험결과, 액상형 접착제 사용 실험체가 더 우수한 인발성능을 보여주었으며, 철근의 매입깊이가 길어질수록 철근의 항복을 먼저 유도하여 높은 최대 인발하중을 보여주었다. 인발성능 실험결과를 통하여 철근의 항복강도보다 접착제의 부착강도를 더 강하게 설계하는 것이 유리한 Glued-in rod 접합부 설계식을 제안하였으며, 접착제의 부착강도의 시공오차를 고려한 보정계수 0.75 또한 제안하였다.

• 한국지반환경공학회 논문집
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• 제24권4호
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• pp.13-22
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• 2023

본 논문에서는 시험적 연구를 통해 록볼트가 지보효과를 발휘하는 시기를 그라우트 강도로 제시하고, 수치해석적 연구를 통해 지반조건과 경계면 강도감소계수에 따른 록볼트 인발 거동을 분석한 연구를 다루었다. 그 결과 록볼트는 그라우트 강도 5 MPa(재령 18시간)에서 지보효과를 발휘하였으며, 경계면 강도감소계수의 영향은 록볼트 변위의 경우 연약한 지반일수록, 그라우트- 지반의 전단응력의 경우 지반의 탄성계수가 높을수록, 그라우트 응력의 경우 모든 지반조건에서 영향이 큰 것으로 분석되었다. 이러한 연구결과는 록볼트 인발시험의 구체적인 기준 재정립과 록볼트 수치해석에 도움이 될 것으로 판단된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.23-26
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• 1995

The objectives of the present study are 1)to find the effect of the diameter of transpedicular screws on their fixational strength in pedicles under static pull-out loading, 2)to determine the biomechanical correlation between the pedicle diameter and the screw diameter, and 3)to find the effects of other factors in the screw design, such as materials, screw pitch, thread height and shape on their fixational strength. Biomechanical tests (Test I) were performed to evaluate the effect of the screw diameter on pull-out strength by using 60 porcine pedicls and six groups of custom-made pedicle screws with different diameters (the major and the minor diameter of the screws used in the testing varied from 4mm upto 9mm and from 3mm upto 8mm, respectively) while all other factors (materials, screw pitch, thread height and shape etc.) were fixed. In Test II, by using 61 porcine pedicles, the relationship between the ratio of the pedicle diameter and the screw diameter(=aspect ratio) of the custum-made screw and the pull-out strength of the screw was investigated. Test III was performed with 94 porcine pedicles and 8 different types of the commercial screws from 6 major productors in order to determine the effect of the screw diameter, pitch and the thread shape on the pull-out strength of the screw, respectively. The results of Test I showed that the axial pull-out resistance of the screw could be increased prportionaly to the screw diameter(P<0.05). But this increase in the pull-out resistance did not found when the screws of 4mm or 9mm in the diameter were employed. It was found from the results of Test II that the screws had its maximum pull-out resistant force when the aspect ratio ranging 40 - 69% (P<0.05). based on the results for the major diameter against the minor diameter of screw, the maximal pull-out resistance was found at 60-65% (P<0.05). According to these biomechanical testing results, it seems that the screw with a moderately large pitch is more desirable and the buttress-shaped screw can provide stronger fixation than the V-shape one can, if other designal factor and conditions were fixed.