• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제5권9호
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• pp.223-228
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• 2016

최근 가상 환경의 발전은 이용자들이 현실 세계를 그대로 반영한 가상 환경을 요구하도록 변화하고 있다. 하지만 현재 서버 및 네트워크 환경은 소수의 이용자가 소수의 그룹을 이루어 함께하는 형태로, 현실 세계를 그대로 반영하지 못하고 있다. 가장 큰 이유 중 하나는 이용자간 정보 동기화에 많은 부하가 발생하기 때문이며, 이러한 부하는 정보 전달 시간을 증가시키게 된다. 본 논문에서는 이러한 문제를 최소화하기 위한 Migration Agent 서버 시스템을 제안한다. Migration Agent 서버는 Field Server 이동시 Player Character의 동기화 과정에서 DBMS의 접근을 최소화하여 응답 시간을 줄여주기 위한 서버로 Field Server간 Player Character 이동을 위한 캐시 서버 역할을 수행한다. 그에 더해 스택형태로 Field Server를 배치함으로 기존 격자 형태로 인해 특정 서버에 부하가 집중되는 것을 보완하였다.

• 한국과학교육학회지
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• 제17권1호
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• pp.85-92
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• 1997

The field is a good learning environment that offers many opportunities. Status of conducting field trip in the middle and high school was investigated As a result, there was few teachers who disagree that a course in science should include learning in the field. Yet, on practical side, teachers who used to conduct the field trip over once a year in science class appeared to be about 23% only. Most of schools conducting field trips hadn't well-planned program for instructional activities. Many of teachers appealed that they should not get release time for conducting an extended field experiences, and that they could not obtained good information in relation to the contents, the methods and strategies of field activities. It says that a good field trip needs administrative and financial surport, many informations, and the teacher's exertion.

• 한국물환경학회지
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• 제25권1호
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• pp.69-75
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• 2009

Water stress has become a major concern in agriculture. Korea suffers from limited agricultural water supply, and wastewater reuse has been recommended as an alternative solution. A study was performed to examine the effects of microorganism concentration in the ponded-water of a paddy rice field with reclaimed-water irrigation for evaluating the microbial risk to farmers and neighborhood children. Most epidemiological studies were performed based on an upland field, and they may not directly applicable to paddy fields. Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion. Their risk value increased significantly high level after irrigation and precipitation. It implies that agricultural activities such as plowing, and fertilizing, and precipitation need be practiced a few days after irrigation considering health risks. The results about field application of the microbial risk assessment using E. coli showed difference according to monitoring time and treatment plot. Result of the microbial risk assessment showed that risk values of ground-water and reclaimed secondary wastewater irrigation were lower than directly use of wastewater treatment plants' effluent. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of E. coli to wastewater reuse in a paddy rice farming.

• 멤브레인
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• 제27권2호
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• pp.121-128
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• 2017

Mesoscale simulation은 원자의 그룹을 묶어서 하나의 단위로서 계산을 수행하는 전산모사 기술로 $ns{\sim}{\mu}s$의 시간 및 $nm{\sim}{\mu}m$의 크기까지 모사가 가능하다. 이러한, mesoscale simulation에는 (1) 입자 자체의 움직임을 계산하여 시스템을 모사하는 particle-based mesoscale, (2) 입자의 움직임이 아닌 chemical potential filed나 density field 등의 변화를 계산하여 시스템을 모사하는 field theory 등의 방법 등이 있는데, 두 방법 모두 고분자의 거시적 특성을 살펴보기 위한 강력한 전산모사 기술로서, 에너지-환경 분야용 고분자 분리막의 다양한 응용분야에서 활용되고 있다. 기존에는 주로 블록 공중합체 분야에서 연구결과들이 보고되었으나, 최근 들어 실제 고분자 분리막의 제조 조건 등을 모사한 연구 결과와 같이 좀 더 응용 분야에 가까운 다양한 에너지-환경용 고분자 분리막 관련 연구가 진행되고 있다. 이온 교환막의 경우에는 이온 전달 채널 형성을 분석 및 예측하기 위한 다양한 mesoscale simulation 결과들이 발표되고 있고, 최근에는 CNT, graphene 등의 나노 첨가물 소재에 대한 연구도 활발히 진행되고 있다. 본 총설에서는 mesoscale simulation 관련 연구에 대한 동향을 정리하고, 어떤 분야에서 유용하게 활용 가능한지 제시하며, 에너지-환경 분야에 종사하는 분리막 연구자들이 mesoscale simulation 기술에 좀 더 쉽게 다가갈 수 있는 기회를 제공하고자 한다.

• Wind and Structures
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• 제17권1호
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• pp.43-68
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• 2013

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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• pp.815-825
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• 2019

Objective: To effectively use corn stover resources as animal feed, the changes in microbial population and chemical composition of corn stover during field exposure, and their silage fermentation and in vitro digestibility were studied. Methods: Corn cultivars (Jintian, Jinnuo, and Xianyu) stovers from 4 random sections of the field were harvested at the preliminary dough stage of maturity on September 2, 2015. The corn stover exposed in the field for 0, 7, 15, 30, 60, 90, and 180 d, and their silages at 60 d of ensiling were used for the analysis of microbial population, chemical composition, fermentation quality, and in vitro digestibility. Data were analyzed with a completely randomized $3{\times}6$ [corn stover cultivar $(C){\times}exposure$ d (D)] factorial treatment design. Analysis of variance was performed using SAS ver. 9.0 software (SAS Institute Inc., Cary, NC, USA). Results: Aerobic bacteria were dominant population in fresh corn stover. After ensiling, the lactic acid bacteria (LAB) became the dominant bacteria, while other microbes decreased or dropped below the detection level. The crude protein (CP) and water-soluble carbohydrate (WSC) for fresh stover were 6.74% to 9.51% and 11.75% to 13.21% on a dry matter basis, respectively. After exposure, the CP and WSC contents decreased greatly. Fresh stover had a relatively low dry matter while high WSC content and LAB counts, producing silage of good quality, but the dry stover did not. Silage fermentation inhibited nutrient loss and improved the fermentation quality and in vitro digestibility. Conclusion: The results confirm that fresh corn stover has good ensiling characteristics and that it can produce silage of good quality.

• Advances in nano research
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• 제11권6호
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• pp.581-593
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• 2021

This model is proposed to describe the buckling behavior of Carbon Nanotubes (CNTs) embedded in an elastic medium taking into account the combined effects of the magnetic field, the temperature, the nonlocal parameter, the number of walls. Using Eringen's nonlocal elasticity theory, thin cylindrical shell theory and Van der Waal force (VdW) interactions, we develop a system of partial differential equations governing the buckling response of CNTs embedded on Winkler, Pasternak, and Kerr foundations in a thermal-magnetic environment. The pre-buckling stresses are obtained by applying airy's stress function and an adjacent equilibrium criterion. To estimate the nonlocal critical buckling load of CNTs under the simultaneous effects of the magnetic field, the temperature change, and the number of walls, an optimization technique is proposed. Furthermore, analytical formulas are developed to obtain the buckling behavior of SWCNTs embedded in an elastic medium without taking into account the effects of the nonlocal parameter. These formulas take into account VdW interactions between adjacent tubes and the effect of terms involving differences in tube radii generally neglected in the derived expressions of the critical buckling load published in the literature. Most scientific research on modeling the effects of magnetic fields is based on beam theories, this motivation pushes me to develop a cylindrical shell model for studying the effect of the magnetic field on the static behavior of CNTs. The results show that the magnetic field has significant effects on the static behavior of CNTs and can lead to slow buckling. On the other hand, thermal effects reduce the critical buckling load. The findings in this work can help us design of CNTs for various applications (e.g. structural, electrical, mechanical and biological applications) in a thermal and magnetic environment.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제21권4호
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• pp.7-15
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• 2015

Purpose: The definition of healing and treatment is different between the East and the West. I suppose that the different definitions of them affect the notion of healing environment in two cultural area. Therefore the aim of this study is to consider the different perspective in healing environment between the East and the West. Methods: Relevant literature review around domestic and foreign reference in fields of medicine and architecture has been conducted to consider the purpose. Results: First, the perspective that the cause of disease stems from inside of body approaches the body from standpoint of healing for recovery. Healing is the way to conquer imbalance by entering into a connection with nature around body. The concept of healing could analyze that it come from relevant perspective. Second, the healing environment in the East is the place where the flow of Qi between, human and human, and, human and environment, keep a balance. The notion of healing environment in the East is the filed of relations. In the West, the notion of healing environment is the place where arouse fine emotions through sensory stimulations. Implications: Recently the studies of healing environment focus on deducing sensory stimulation factors scientifically in the perspective of the West. But the healing environment couldn't be possible without the notion of place of relations. In the future, the notion of healing environment as the field of relations in the East has to be concerned.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.690-693
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• 2004

This paper proposes a multi-resolution electrostatic potential field (MREPF) based solution to the mobile robot path planning and collision avoidance problem in 2D dynamic environment. The MREPF is an environment method in calculation time and updating field map. The large scale resolution map is added to EPF and this resolution map interacts with the small scale resolution map to find an optimal solution in real time. This approach can be interpreted with Atlantis model. The simulation studies show the efficiency of the proposed algorithm.

• KIEAE Journal
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• 제11권4호
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• pp.47-54
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• 2011

Construction companies find it increasingly necessary to reduce the cost as the construction market has been suffering from a depression and the industrial environment has been changing fast lately. The cost cut demands the productivity management of the field operations, which can be made feasible by assigning an appropriate number of managers on the construction site. However, previous studies are focused on the labor productivity and construction companies take into account only the revenue per worker in organizing the staff. The purpose of this study is to research the model for calculating the field management manpower in accordance with the characteristic of project and site conditions which are usually considered in the beginning of the construction project. The data about apartment building projects of domestic large constructors and factors related to them were statistically analyzed. The results of this study can be used to calculate the necessary field management manpower in accordance with the characteristic of project.