• 청정기술
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• 제17권4호
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• pp.406-411
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• 2011

포항철강산업단지에서 발생하는 폐열을 회수하기 위하여 주요 기업의 폐에너지 발생 규모에 대한 데이터베이스를 설문조사를 통해 구축하고, 가시적인 기법을 적용하여 에너지 교환망 구축방안을 고려하였다. 폐열의 온도 수준, 유효에너지 발생량, 폐에너지 발생 기업과 예상 수요 기업의 거리, 구축비용 등의 관점에서 잠재성이 높은 에너지 교환망을 제시하고 경제성을 평가하였다. 최종 제안된 4개 기업의 에너지 교환망의 투자비 회수기간은 평균 2.8년이고, 에너지 절감량은 연간 4,778 TOE로 분석되었다. 현재 사용되는 LNG를 폐열 회수로 대체하면 연간 약 11,160 $CO_2$ ton을 감축할 수 있다.

• 디지털융복합연구
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• 제11권7호
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• pp.173-184
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• 2013

퀀텀정보통신기술은 원자 정도의 매우 작은 소립자를 의미하는 퀀텀의 속성을 연구하는 퀀텀역학에 기반을 두고 연구개발이 진행되는 분야로서, 기존 컴퓨터의 역량을 뛰어넘는 엄청난 계산능력과 커뮤니케이션 파워를 보일 수 있다. 퀀텀정보기술은 기존 컴퓨터의 0과 1을 이용한 계산방식 대신 소위 0과 1 그리고 이 두 상태의 중첩상태를 이용한다. 기존에 생각조차 하기 힘들었던 퀀텀현상의 적극적 활용은 새로운 퀀텀기반 디바이스의 개발을 촉진시켰으며 이론적으로나마 퀀텀컴퓨터의 개발이 가능함으로 보여주고 있다. 이 분야의 새로운 발견은 초정밀 센서, 이미징 처리 디바이스, 새로운 컴퓨터 연산 패러다임의 개발로 이어져 기존에는 생각하기도 힘들었던 문제들을 효율적으로 해결해 나갈 수 있는 방법론은 제시하고 있다. 결과적으로 퀀텀정보통신분야는 특정 산업분야 전체를 파괴하고 새로운 산업을 창조할 수 있는 글로벌 경제구조의 변혁의 원천이 될 수 있다.

• Advances in Computational Design
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• 제5권1호
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• pp.1-11
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• 2020

Soil is the fundamental element in the construction process. Soil problems affect the safety of the structures, even so the high quality of the structures and so, bad soil found the structures will affect the lifetime or even destroy the structures built on it. Therefore, the study of soil is an important step in the construction process and the investigation of the most effective characteristics of a special kind of soil (shale soil), i.e. Atterberg limits, swelling pressure, swelling potential and unconfined compression strength, are the most effective soil properties. A big projects will be constructed in new urban extension areas with expansive shale soils, like at Al-Kawamil and new Akhmim shale soils which associated with soil problems, treatment system should be used to ensure the stability of the soil under the structures foundations one of the most effective methods is by adding lime solution to the soil by specific quantities, which affect on the properties of the shale soil by decreasing the swelling and increasing the compressive strength of the treatment soils. Experimenting with the soil added to the lime, it was found that the addition of lime solution 6% improve c j the properties of the soil. The results of the tests showed the high effectiveness of using lime in the treatment of Al-Kawamil soil

• 농업과학연구
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• 제43권4호
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• pp.537-546
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• 2016

The development of models for agriculture systems, especially for crop production, has supported the prediction of crop yields under various environmental change scenarios and the selection of better crop species or cultivar. Crop models could be used as tools for supporting reasonable nutrient management approaches for agricultural land. This paper outlines the simplified structure of main crop models (crop growth model, crop-soil model, and crop-soil-environment model) frequently used in agricultural systems and shows diverse application of their simulated results. Crop growth models such as LINTUL, SUCROS, could provide simulated data for daily growth, potential production, and photosynthesis assimilate partitioning to various organs with different physiological stages, and for evaluating crop nutrient demand. Crop-Soil models (DSSAT, APSIM, WOFOST, QUEFTS) simulate growth, development, and yields of crops; soil processes describing nutrient uptake from root zone; and soil nutrient supply capability, e.g., mineralization/decomposition of soil organic matter. The crop model built for the DSSAT family software has limitations in spatial variability due to its simulation mechanism based on a single homogeneous field unit. To introduce well-performing crop models, the potential applications for crop-soil-environment models such as DSSAT, APSIM, or even a newly designed model, should first be compared. The parameterization of various crops under different cultivation conditions like those of intensive farming systems common in Korea, shortened crop growth period, should be considered as well as various resource inputs.

• 대한토목학회논문집
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• 제32권6D호
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• pp.565-569
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• 2012

본 연구는 부산, 대구, 광주, 대전 등 4개 대도시권역을 대상으로 대중교통서비스가 열악한 대중교통사각지역을 선정한 후 이들 지역간을 운행하는 새로운 급행대중교통수단 도입 시 기성 시가지내 통행자들과 수단선택 행태가 어떻게 다른지를 분석하기위해 SP 조사(stated preference survey)를 통한 수단선택 행태변화에 대해 네스티드 로짓모형을 구축하여 분석하였다. 연구결과 대중교통사각지대는 잠재 대중교통수요가 많아 기성시가지에 비해 자가용통행으로부터 새로운 대중교통수단으로 전환하는 통행전환 비율이 매우 높은 것으로 분석되었다. 이러한 연구결과는 향후 대도시권 외곽 순환도로 혹은 외곽지역에서 도심지역으로 연결되는 간선도로를 활용한 새로운 급행 대중교통체계 도입시 수요변화 평가와 외곽지역의 대중교통 잠재수요 분석에도 활용될 수 있을 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제75권6호
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• pp.747-769
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• 2020

This paper provides a semi-analytical approach to investigate the variations of 3D displacement components, electric potential, stresses, electric displacements and transverse vibration frequencies in laminated piezoelectric composite plates based on the scaled boundary finite element method (SBFEM) and the precise integration algorithm (PIA). The proposed approach can analyze the static and dynamic responses of multilayered piezoelectric plates with any number of laminae, various geometrical shapes, boundary conditions, thickness-to-length ratios and stacking sequences. Only a longitudinal surface of the plate is discretized into 2D elements, which helps to improve the computational efficiency. Comparing with plate theories and other numerical methods, only three displacement components and the electric potential are set as the basic unknown variables and can be represented analytically through the transverse direction. The whole derivation is built upon the three dimensional key equations of elasticity for the piezoelectric materials and no assumptions on the plate kinematics have been taken. By virtue of the equilibrium equations, the constitutive relations and the introduced set of scaled boundary coordinates, three-dimensional governing partial differential equations are converted into the second order ordinary differential matrix equation. Furthermore, aided by the introduced internal nodal force, a first order ordinary differential equation is obtained with its general solution in the form of a matrix exponent. To further improve the accuracy of the matrix exponent in the SBFEM, the PIA is employed to make sure any desired accuracy of the mechanical and electric variables. By virtue of the kinetic energy technique, the global mass matrix of the composite plates constituted by piezoelectric laminae is constructed for the first time based on the SBFEM. Finally, comparisons with the exact solutions and available results are made to confirm the accuracy and effectiveness of the developed methodology. What's more, the effect of boundary conditions, thickness-to-length ratios and stacking sequences of laminae on the distributions of natural frequencies, mechanical and electric fields in laminated piezoelectric composite plates is evaluated.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1226-1236
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• 2022

Because students majoring in construction-related fields must develop a broad repository of knowledge and skills, effective transferal of these is the primary focus of most academic programs. While inculcation of this body of knowledge is certainly critical, actual construction projects are complicated ventures that involve levels of risk and uncertainty, such as resistant neighboring communities, unforeseen weather conditions, escalating material costs, labor shortages and strikes, accidents on jobsites, challenges with emerging forms of technology, etc. Learning how to develop a level of discernment about potential ways to handle such uncertainty often takes years of costly trial-and-error in the proverbial "school of hard knocks." There is therefore a need to proactively expedite the development of a sharpened intuition when making decisions. The AGC Education and Research Foundation case study committee was formed to address this need. Since its inception in 2011, 14 freely downloadable case studies have thus far been jointly developed by an academics and industry practitioners to help educators elicit varied responses from students about potential ways to respond when facing an actual project dilemma. AGC case studies are typically designed to focus on a particular concern and topics have thus far included: ethics, site logistics planning, financial management, prefabrication and modularization, safety, lean practices, preconstruction planning, subcontractor management, collaborative teamwork, sustainable construction, mobile technology, and building information modeling (BIM). This session will include an overview of the history and intent of the AGC case study program, as well as lively interactive demonstrations and discussions on how case studies can be used both by educators within a typical academic setting, as well as by industry practitioners seeking a novel tool for their in-house training programs.

• 수산경영론집
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• 제53권4호
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• pp.27-49
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• 2022

This study focused on diagnosing and analyzing the level of sustainable development for each fishing communities by applying the sustainable development index in the fishing communities to support the policy of revitalizing the fishing communities. In terms of methodology, diagnostic indicators for rural areas were used through previous studies and literature surveys, and three categories, five fields and 27 indicators were finally selected through collecting opinions from experts. After deriving the weight for each indicator in detail, the final sustainable development index of the fishing communities was applied to fishing village fraternity. Based on the results of the analysis of the application of sustainable development cases in fishing communities, policy support should be implemented differentially according to regional decline factors and potential growth factors. In the population and social sector, it is necessary to consider ways to reduce population and reduce aging. In the industrial and economic sectors, fishing activation and systematic support for fishing-related industries should be provided. In the marine and built environment sector, the government's active project execution and budget support are required. In addition, it is expected to be used in various ways in the process of developing fishing communities and establishing revitalization plans that reflect the characteristics of the region.

• Steel and Composite Structures
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• 제36권2호
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• pp.197-211
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• 2020

Application of the steel ring as a type of seismic fuse has been one of the efforts made by researchers in recent years aiming to enhance the ductility of the bracing systems which in turn, possesses various advantages and disadvantages. Accordingly, to alleviate these disadvantages, an innovative bracing system with a diamond scheme equipped with a steel ring is introduced in this paper. In this system, the braces and yielding circular damper act in parallel whose main functionality is to increase ductility, energy absorption and mitigate drawbacks of the existing bracing systems, in which the braces and yielding circular damper act in parallel. To conduct the experimental tests, specimens with three types of rigid, semi-rigid and pinned connections were built and subjected to cyclic loading so that their performance could be analyzed. Promisingly, the results indicate both great applicability and efficiency of the proposed system in energy absorption and ductility. Moreover, it was concluded that as the braces and damper are in parallel, the use of a steel ring with smaller size and thickness would result in higher energy absorption and load-resisting capacity when compared to the other existing systems. Finally, to assess the potential of numerically modeling the proposed system, its finite element model was simulated by ABAQUS software and observed that there is a great agreement between the numerical and experimental results.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권2호
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• pp.90-94
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• 2006

We report on the growth and characterization of InGaN/GaN MQWs on two different types of sapphire substrates and GaN substrates. The InGaN/GaN MQWs are grown by using metalorganic chemical vapor deposition. Our analysis of the satellite peaks in the HRXRD patterns shows, GaN substrates InGaN/GaN MQW compared to sapphire substrates InGaN/GaN MQW, more compressive strain on GaN substrates than on sapphire substrates. However, results of optical investigation of InGaN/GaN MQWs grown on GaN substrates and on sapphire substrates, which have lower Stokes-like shift of PL to GaN substrates compared to sapphire substrates, are shown to the potential fluctuation and the quantum-confined Stark effect induced by the built-in internal field due to spontaneous and straininduced piezoelectric polarizations. The InGaN/GaN MQWs are shown to quantify the Stokes-like shift as a function of x.