• Steel and Composite Structures
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• 제49권1호
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• pp.47-64
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• 2023

Due to their efficient use of materials, hybrid reinforced concrete-steel (RCS) systems provide more practical and economic advantages than traditional steel and concrete moment frames. This study evaluated the seismic design factors and response modification factor 'R' of RCS composite moment frames composed of reinforced concrete (RC) columns and steel (S) beams. The current International Building Code (IBC) and ASCE/SEI 7-05 classify RCS systems as special moment frames and provide an R factor of 8 for these systems. In this study, seismic design parameters were initially quantified for this structural system using an R factor of 8 based on the global methodology provided in FEMA P695. For analyses, multi-story (3, 5, 10, and 15) and multi-span (3 and 5) archetypes were used to conduct nonlinear static pushover analysis and incremental dynamic analysis (IDA) under near-field and far-field ground motions. The analyses were performed using the OpenSees software. The procedure was reiterated with a larger R factor of 9. Results of the performance evaluation of the investigated archetypes demonstrated that an R factor of 9 achieved the safety margin against collapse outlined by FEMA P695 and can be used for the design of RCS systems.

• Earthquakes and Structures
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• 제25권5호
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• pp.343-358
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• 2023

The superelastic viscous damper (SVD) is a hybrid passive control device comprising a viscoelastic damper and shape memory alloy (SMA) cables connected in series. The SVD is an innovative damper through which a large amount of seismic energy can dissipate. The current study assessed the seismic collapse induced by steel moment-resisting frames (SMRFs) equipped with SVDs and compared them with the performance of special MRFs and buckling restrained brace frames (BRBFs). For this purpose, nonlinear dynamic and incremental dynamic analysis (IDA) were conducted in OpenSees software. Both 5- and 9-story special MRFs, BRBFs, and MRFs equipped with the SVDs were examined. The results indicated that the annual exceedance rate for maximum residual drifts of 0.2% and 0.5% for the BRBFs and MRFs with SVDs, respectively, were considerably less than for SMRFs with reduced-beam section (RBS) connections and that the seismic performances of these structures were enhanced with the use of the BRB and SVD. The probability of collapse due to residual drift in the SVD, BRB, and RBS frames in the 9-story structure was 1.45, 1.75, and 1.05 times greater than for the 5-story frame.

• International Journal of Computer Science & Network Security
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• 제24권7호
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• pp.177-185
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• 2024

Web science, a general discipline of learning is presently at high demand of expertise with ideas to develop software-based WebApps and MobileApps to facilitate user or customer demand e.g. shopping etc. electronically with the access at their smartphones benefitting the business enterprise as well. A worldwide-computerized reservation network is used as a single point of access for reserving airline seats, hotel rooms, rental cars, and other travel related items directly or via web-based travel agents or via online reservation sites with the advent of social-web, e-commerce, e-business, from anywhere-on-earth (AoE). This results in the accumulation of large and diverse distributed databases known as big data. This paper describes a novel intelligent web-based electronic booking framework for e-business with distributed computing and data mining support with the detail of e-business system flow for e-Booking application architecture design using the approaches for distributed computing and data mining tools support. Further, the importance of business intelligence and data analytics with issues and challenges are also discussed.

• 한국소프트웨어감정평가학회 논문지
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• 제15권2호
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• pp.111-119
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• 2019

존 스마트그리드 기기 인증 체계는 DCU와 검침 FEP 및 MDMS에 집중되어 있으며 스마트미터에 대한 인증체계는 확립되지 않은 상황이다. 현재 몇몇 암호칩이 개발되었지만, 낮은 강도의 단순 암호화 수준에 머물러 있어 PKI 인증체계를 완성하기에는 어려움이 있다. 스마트그리드는 기존 전력망과 달리 개방형 양방향 통신을 기반으로 함에 따라 정보보안 취약성이 높아지면서 사고 위험 증가하고 있다. 하지만 스마트미터에는 PKI가 적용되기 어려워, 조작한 패킷을 보내 운영시스템에 거짓 정보 전송으로 시스템 정지 등의 사고가 발생할 가능성 존재한다. 하드웨어 제약사항이 많은 스마트미터에 기존 PKI 인증서를 발급할 경우 인증 및 인증서 갱신이 어렵기 때문에 스마트미터의 열악한 성능(Non-IP 네트워크, 프로세서, 메모리 및 저장소 공간 등)에서도 작동 가능한 초경량 암호 인증 프로토콜을 설계 구현하였다. 실험 결과 Cortex-M3 환경에서도 경량 암호 인증 프로토콜을 빠른 시간 내에 수행 할 수 있었으며, 앞으로 스마트그리드 산업에서의 더 안전한 보안성을 갖춘 인증 시스템을 마련하는데 도움을 줄 수 있을 것으로 기대한다.

• 한국방재안전학회논문집
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• 제15권4호
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• pp.39-46
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• 2022

기후변화로 인해 집중호우의 강우 특성은 과거와는 다르게 변화하고 있으며 불확실성 또한 크게 증가하고 있다. 이에 더해 도시개발, 인구집중 등의 변화는 홍수피해를 가중시키고 있다. 대다수의 도심지 침수 원인은 복합적이므로 해당 지역의 여건들을 고려하여 적절한 침수방어계획을 수립하는 것이 매우 중요하다. 이를 위해 정부는 지자체별로 방재성능목표라는 기준을 수립하고 있다. 2010년 처음 방재성능목표 개념이 제시된 이후, 몇 차례 설정 기준 등이 변화하였지만 전체적인 기술, 방법론, 절차 등은 유지되어 왔다. 따라서, 본 연구에서는 도시 방재성능목표 설정 및 전반적인 평가방법에 대한 고찰을 위해 계량정보분석(Scientometric Analysis) 방법을 활용하여 도시 방재성능과 관련된 연구 및 기술을 검토하였다. 계량정보분석은 논문, 문헌 등의 자료를 기반으로 해당 분야의 트렌드를 확인하고 새로운 지식 및 정보를 도출하는 방법으로, 본 연구에서는 1990년부터 2021까지 최근 약 30년동안 Web of Science의 관련 방재성능과 관련된 논문을 수집하였다. 계량정보 분석 소프트웨어인 Citespace를 활용하여 인용분석을 포함한 저자, 연구기관, 국가 및 연구동향 등을 파악하였다. 분석결과, 도시 방재성능의 기술적인 부분 외에도 자산 평가 개념 도입 등 의사결정에 필요한 고려요소들이 파악되었다. 향후 핵심키워드를 구체화하여 각 기술별 방재성능평가에 대한 고찰을 실시한다면 국내의 평가기준 및 절차를 고도화 할 수 있을 것이라 기대된다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권6호
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• pp.383-394
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• 2013

CPU, 메모리 등 모바일 디바이스의 제한된 자원문제를 해결하기 위한 방법으로, 모바일 디바이스의 자원이 아닌 클라우드 서비스 또는 PC등 외부 자원을 사용하는 모바일 클라우드 컴퓨팅(Mobile Cloud Computing, MCC)이 부각되고 있다. 전형적인 MCC 환경(MCC Environment, MCE)은 다른 운영체제 및 플랫폼을 가지는 여러 개의 노드, 모바일 애플리케이션과 서비스들로 구성되어 있고, 중앙관리자는 MCE 전체 품질이 일정 수준 이상을 유지하도록 관리 태스크를 수행한다. 그러나, 노드 수, 모바일 애플리케이션 수, 서비스의 수가 많아지고 서비스 실행빈도가 높아질 경우, 중앙 관리자의 관리 태스크 과중으로 병목현상과 성능저하 문제가 제기될 수 있다. 본 논문에서는 이러한 대규모 MCE의 병목과 성능저하 문제를 해결하고, 전체 품질을 안정화시키기 위한 클러스터링(Clustering) 기반의 최적화 기법을 제안한다. 본 기법을 적용하면 MCE의 전체 품질을 안정화시키기 위한 부하를 최소화하면서, 능동적이며 자율적인 방식으로 품질을 보장할 수 있다.

• 임상간호연구
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• 제23권3호
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• pp.376-387
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• 2017

Purpose: This study was to systematically review the contents and effects of nurse-led transitional care programs for discharged patients from hospital to home. Methods: Randomized controlled trials published between 2005 and 2015 were searched in Pubmed, Embase, Cochrane(Central Register of Controlled Trials) and CINAHL. Data were analyzed using Cochrane Review Manager(Revman) software 5.3. Results: Nine studies were selected and analyzed. Patient assessment, education and discharge planning were included in pre-discharge phase. Referring, communication and care planning were performed by nurses in transition phase. Home and phone visits, monitoring and multidisciplinary advices were included in post-discharge phase. Various outcome measures such as hospital utilization(30 days readmission and emergency department visit), quality of life, and cost were used to identify effectiveness of nurse-led transitional care programs. 30 days readmission(OR=.73, 95% CI 0.54, 0.98; p=.03) and emergency department visit(OR=.67, 95% CI 0.50, 0.88; p=.005) were statistically significant in meta-analysis. However, participant blinding was not done in seven studies which put at the risk of performance bias. Conclusion: The results indicated that nurse-led transitional care program is effective in reducing unnecessary hospital utilization. Nevertheless, small sample size and risk at performance bias are the limitation of this study. Thus, we suggest that well-designed randomized controlled trials need to be conducted.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.149-155
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• 2010

Currently various safety tests are being performed in many countries with growing interest in vehicle safety. However the vehicles which have good safety performance in these tests could not secure the good performance in real car to car accident. So new test protocol using progressive deformable barrier (PDB) was proposed by EEVC in Europe, NHTSA in USA and some vehicle manufacturers, etc. The target of PDB test is to control partner protection in addition to self-protection on the same test. The proposal is to update current ECE R.94 frontal ODB test. So barrier, impact speed, overlap are changed to avoid bottoming-out in the test configuration. In this paper 3 different tests (R.94, EuroNCAP and PDB test) were carried out using current production vehicles with same structure. The results of these tests were compared to understand PDB test. As a result PDB test shows the highest vehicle deceleration and dummy injury because PDB offers a progressive increase in stiffness in depth and height. However vehicle intrusion was affected with rather test velocity than stiffness of deformable barrier. PDB deformation data is used for partner protection assessment using PDB software and it shows that the test vehicle is rather not aggressive.

• 한국유기농업학회지
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• 제20권4호
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• pp.475-490
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• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2367-2375
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• 2022

In this work, we propose a new mechanistic model for the treatment of helium behaviour at the grain boundaries in oxide nuclear fuel. The model provides a rate-theory description of helium inter-granular behaviour, considering diffusion towards grain edges, trapping in lenticular bubbles, and thermal resolution. It is paired with a rate-theory description of helium intra-granular behaviour that includes diffusion towards grain boundaries, trapping in spherical bubbles, and thermal re-solution. The proposed model has been implemented in the meso-scale software designed for coupling with fuel performance codes SCIANTIX. It is validated against thermal desorption experiments performed on doped UO₂ samples annealed at different temperatures. The overall agreement of the new model with the experimental data is improved, both in terms of integral helium release and of the helium release rate. By considering the contribution of helium at the grain boundaries in the new model, it is possible to represent the kinetics of helium release rate at high temperature. Given the uncertainties involved in the initial conditions for the inter-granular part of the model and the uncertainties associated to some model parameters for which limited lower-length scale information is available, such as the helium diffusivity at the grain boundaries, the results are complemented by a dedicated uncertainty analysis. This assessment demonstrates that the initial conditions, chosen in a reasonable range, have limited impact on the results, and confirms that it is possible to achieve satisfying results using sound values for the uncertain physical parameters.