• 대한기계학회논문집A
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• 제26권7호
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• pp.1438-1445
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• 2002

For robotic endoscope, some researchers suggest pneumatic actuators based on inchworm motion. But, the existing endoscopes have not been replaced completely because human intestine is very sensitive and susceptible to damage. We design and test a new locomotion of robotic endoscope that allows safe maneuverability in the human intestine. The actuating mechanism is composed of two solenoids at each side and a single permanent magnet. When the current direction is reversed, repulsive force and attractive at the opposition side propels permanent magnet. Impact force against robotic endoscope transfers momentum from moving magnet to endoscope capsule. The direction and moving speed of the actuator can be controlled by adjustment of impact force. Modeling and simulation experiments are carried out to predict the performance of the actuator. Simulations show that force profile of permanent magnet is the dominant factor for the characteristic of the actuator. The results of simulations are verified by comparing with the experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.664-669
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• 2001

The characteristics of dual coaxial jet which composed of inner supersonic nozzle of 26500 in constant expansion rate with 1.91 design Mach number and outer converging one with $40^{\circ}$ converging angle with the variation of outer nozzle stagnation pressures are experimentally investigated in this paper. In which the stagnation pressure for the inner supersonic nozzle is 750kPa thus, the inner jet leaving the nozzle is slightly underexpanded. The plenum pressures of outer nozzle are varied from 200 to 600kPa. Flow visualizations by shadowgraph method, impact pressure and centerline static pressure measurements of dual coaxial jet are presented. The results show that the presence of outer jet affects significantly the structures and pressure distributions of inner jet. And outer jet causes Mach disk which does not appear for the case of single jet stream. As the stagnation pressure of outer jet increases, impact pressure undulation is severe, but the average impact pressure keeps high far downstream.

• 동력기계공학회지
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• 제17권1호
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• pp.27-35
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• 2013

SCR (Selective Catalytic Reduction) on DPF (Diesel Particulate Filter) is a multi-functional after-treatment device which integrates soot filtration and DeNOx function into a single can. Because of its advantage in package and cost, the SCR on DPF is considered as a potential candidate for future application. It inherently employes wall flow type monolithic reactor so ash included in exhaust gas may deposit inside the inlet channel of this device. This study is intended to identify the impact of ash deposit on SCR reaction under wall flow type monolithic reactor. Simulation approach is used so relevant species transport equations for wall flow type monolith is derived. These equations can be solved together with momentum conservation equations and give solution for conversion performance. Both ash deposit and clean catalyst case are simulated and comparison of these two cases gives an insight for the impact of ash deposit on conversion performance. Ash deposit can be classified as ash layer and ash plug. and impact of ash deposit is described along with different morphology of ash deposit.

• Journal of Information Science Theory and Practice
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• 제5권2호
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• pp.48-61
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• 2017

This paper uses 601 cited papers of Pakistani LIS researchers with the purpose to examine the individual performance of these Library and Information Science (LIS) researchers in terms of their research output and its impact on the LIS (national/international) literature by using various bibliometric indicators. A list of 139 authors was compiled with the help of the Library, Information Science, and Technology Abstracts (LISTA) and some other sources. Data were collected from Google Scholar and SPSS version 20 was utilized in order to identify the relationship between self-citations and various performance indices of the authors. The average citations received per paper vary from 1.80 to 10.08. About half of the papers were single-authored whereas less than one-fifth were by three or more authors. The authors who worked in collaboration produced more papers and received more citations. The h-index, g-index, hI-index, hI-norm, and e-index were used to determine the rank for each author. The intra-group citations grid revealed the volume of self-citations and a small group who cite each other more due to close academic and social relationships. The correlations between self-citations and the impact indices used revealed significant differences. Findings are useful for concerned institutions regarding award, promotions, etc. Further, future research should seriously consider the self-citations and social networking of authors while examining their citations-based research performance.

• 한국해양공학회지
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• 제21권6호
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• pp.42-46
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• 2007

The impact of a single wave generated by a dam break with a tall structure is modeled with a three-dimensional version of the Moving particle semi-implicit (MPS) method. The particle method is more feasible and effective than methods based on grid connection problems involving violent free surface motions. In the present study, the Tsunami impact load and the change of longitudinal velocity component around the structure, which are obtained from the numerical simulation, are compared to those from experiments.

• Architectural research
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• 제20권4호
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• pp.137-145
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• 2018

The nondestructive test is widely used in the field of diagnosis and maintenance to evaluate the degree of damaging of structures caused by aging, and the demand for this test method is expected to continue increasing. However, there is a lack of standards related to the nondestructive test, and South Korea is relying heavily on developed nations for original technologies related to diagnosis. It is an urgent task to establish a nondestructive test method appropriate for the circumstance of South Korea. The purpose of this study is to compare and analyze estimated error of compressive strength in single-story structures comprised of vertical and horizontal reinforced concrete members using the impact testing method and rebound hardness method, which are nondestructive test methods, and to review on-site applicability of these methods. Based on compressive strength of the structures estimated, overall mean error was 21.2% for the impact testing method and 15.6% for the rebound hardness method. The necessity of a reliable diagnostic method based on compound nondestructive test methods to increase accuracy of estimation was confirmed.

• 한국환경과학회지
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• 제32권8호
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• pp.543-553
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• 2023

Weather forecasts and advisories provided by the national organizations in Korea that are used to identify and prevent disaster associated damage are often ineffective in reducing disasters as they only focus on predicting weather events (World Meteorological Organization(WMO ), 2015). In particular, typhoons are not a single weather disaster, but a complex weather disaster that requires advance preparation and assessment, and the WMO has established guidelines for the impact forecasting and recommends typhoon impact forecasting. In this study, we introduced the Typhoon-Ready System, which is a system that produces pre-disaster prevention information(risk level) of typhoon-related disasters across Korea and in detail for each region in advance, to be used for reducing and preventingtyphoon-related damage in Korea.

• 환경영향평가
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• 제12권3호
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• pp.137-150
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• 2003

This study aims to survey whether local governments have legislated laws and regulations on environment impact assessment system, to compare and analyze specific projects and their scale, assessment items, and procedures & discussion process, to identify issues and generate improvement plans, and to suggest a direction for future legislation to local governments that plan to legislate laws and regulations in the future. Major outcome of the study are as follows. First, terminologies used for environment impact assessment by local governments need to be unified. Also, laws and regulations need to be legislated soon. Second, in "urban development project" areas, a total of nine project areas including "quarrying of soil and stone, sand, gravel, and minerals" was essential common projects. A total of six project types were added or newly established compared to national systems. Among them, four project types were added within national-level project areas and two project types were not available under the national-level project areas and newly added due to the nature of local governments. Third, in terms of project scale, scale enhancement of "urban development project" was most common. Analysis showed that in case of clean natural environment such as Cheju Island, it is necessary to consider reinforcing project areas where development activities take place directly in forests or rivers such as "industrial base and complex development", "water resource development", and "development of tourism complex." Fourth, the discussion and review procedures of assessment reports were similar to those at government level. However, in case of Seoul city, it is required to write a "preparation plan" before drafting an assessment report. The city features partial introduction of scoping and screening, which allows to exempt discussion procedures if impact on environment is found to be minimal after drafting the assessment report. In case of national-level, it has a dual system that is split between Ministry of Construction and Transportation and Ministry of Environment. However, in case of environment impact assessment of local governments, it is a single system where city mayors and provincial governors are in charge of both project execution and environmental assessment. Therefore, the most important task is how to satisfy objectiveness and accountability.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
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• pp.205-210
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• 2006

해양구조물 설계시 급격한 파랑에 의한 충격력은 구조물 안전을 위한 중요한 설계인자이다. 이러한 충격력은 과도한 하중이 극히 짧은 시간 사이에 발생하는 현상으로 실험적 또는 수치해석적으로 해석하기 매우 어려운 문제이다. 본 연구에서는 급격한 파랑에 의한 충격력을 해석하기 위하여 수치파수조를 이용하여 N.S. 방정식에 기반한 수치해석을 수행하였다. 임의파를 선형중첩에 기반하여 조파기를 작동시켜 재현하였고 다블록격자하에서 수직실린더에 작용하는 충격력을 수치해석하였다. 한편 자유표면은 V.O.F. 및 local height function을 이용하여 추적하였다. 수치해석 검증을 위하여 수치해석 및 실험 결과와 비교를 수행하였는데 비교적 만족할 수 있는 결과를 확인하였으나 해양구조물 설계시 유용한 결과를 얻기 위해서는 쇄파와 같은 극한파 재현과 극한파에 의한 충격력에 대한 많은 연구가 지속되어야 함을 알 수 있었다.

• 한국병원경영학회지
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• 제26권3호
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• pp.68-83
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• 2021

Background: It is widely acknowledged that single bedrooms have many potential advantages compared to multiple bedrooms. However, Korea has a reimbursement system that patients have to pay the additional fee if they will use single bedroom or pay-bed (1-3 bedroom). There is little research on patients' bed selection and relationship between patient satisfaction and bed type in the Korean setting. Methods: Using the 2017 Korea Health Panel (KHP) Survey data, we modified bed type by two dichotomous variables: single bedroom vs. multiple bedroom (2+ bedrooms) and pay-bed (1-3 bedroom) vs. reimbursed bed (4+ bedroom). Multivariate logistic regression is performed to determine the factors affecting the patient's choice of room types. Multivariate regression analysis was conducted to examine how hospital room types are affecting patient satisfaction. Results: Single room and pay-bed (1-3 bedroom) use was influenced by patient age (19- years old), male, a person at work, hospitalizing in a clinic, and birth. After controlling variables of the behavioral model of medical utilization, the association between patient satisfaction and use of single bedroom & pay-bed (1-3 bedroom). Cause of hospitalization, major treatment, and recognition of unnecessary care are statistically significant variables on patient satisfaction. Conclusion: Although the single room is about the standard for newly built hospitals in western countries, it remains unclear that single room or pay-bed (1-3 bedroom) has positive effects on patient's outcomes and satisfaction. In this empirical study, the difference in patient satisfaction by bedroom type was not noticeable. In terms of bed management by hospital staff, securing patient credibility in hospital care is an important task. Patients' perception of whether medical staffs have encouraged unnecessary treatment or tests has a significant impact on patient's satisfaction.