• Computers and Concrete
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• 제2권1호
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• pp.31-53
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• 2005

In the present structural codes the safety verification is based on a linear analysis of the structure and the satisfaction of ultimate and serviceability limit states, using a semi-probabilistic security format through the consideration of partial safety factors, which affect the action values and the characteristic values of the material properties. In this context, if a non-linear structural analysis is wanted a difficulty arises, because the global safety coefficient, which could be obtained in a straightforward way from the non-linear analysis, is not directly relatable to the different safety coefficient values usually used for the different materials, as is the case for reinforced concrete structures. The work here presented aims to overcome this difficulty by proposing a methodology that generalises the format of safety verification based on partial safety factors, well established in structural codes within the scope of linear analysis, for cases where non-linear analysis is needed. The methodology preserves the principal assumptions made in the codes as well as a reasonable simplicity in its use, including a realistic definition of the material properties and the structural behaviour, and it is based on the evaluation of a global safety coefficient. Some examples are presented aiming to clarify and synthesise all the options that were taken in the application of the proposed methodology, namely how to transpose the force distributions obtained with a non-linear analysis into design force distributions. One of the most important features of the proposed methodology, the ability for comparing the simplified procedures for second order effects evaluation prescribed in the structural codes, is also presented in a simple and systematic way. The potential of the methodology for the development and assessment of alternative and more accurate procedures to those already established in codes of practice, where non-linear effects must be considered, is also indicated.

• 대한인간공학회지
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• 제32권4호
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• pp.321-331
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• 2013

Objective: The aim of this study is to review the literatures on the regulation, standard and guideline for the human vibration in Korea and other countries. Background: This review can be used to prevent various diseases caused by the human vibration as a basis for the development of the policy. Results: In Korea, the general employers' duties related to human vibration are set forth the Health Measures(Article 24) in the Occupational Safety and Health Act. And then an employer shall take measures to protect the health of the workers concerned by improving other working conditions relating to working hours for the vibration prevention measures referred to in Article 24 of the Act. The European Union adopted a Directive in 2002 on minimum requirements for the health and safety of workers exposed to vibration. New Regulations on Vibration at Work will be introduced in Great Britain on 2005 to implement the Directive. In the U.S., both ANSI and ACGIH adopted the ISO standard for measurement and suggested exposure action and limit values. In Japan, the Ministry of Labor decided that the vibration syndrome among operators of rock drills and riveters etc. could be included in an occupational disease(1947). In addition, ISO standard was based on proposals and draft documents of many countries such as U.K, Japan and European, etc. Conclusion: In Korea, Occupational Safety and Health Act prevent vibration to health, but do not include exposure limits. It is therefore important to consider the new duties regarding to vibration risks added to the general duties.

• 전자공학회논문지CI
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• 제48권5호
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• pp.42-48
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• 2011

에이전트는 특정 목적을 위해 행동을 하는데 이것은 자율지능형 가상군(Computer Generated Forces, CGF)의 공통된 요소이다. 목적을 달성하기 위해 지정된 스크립트를 따라 행위를 하거나 업무 수행의 계획을 세우는 것을 기본적인 에이전트의 지능이라 볼 수 있는데 이보다 더 발전된 지능 에이전트는 계획을 세우는 것뿐만 아니라 계획했던 수행이 어려울 때 계획을 다시 수정하거나 새로운 계획을 적응적으로 만들어내는 것이다. 계획을 수행 할 때 에이전트가 목적을 위한 적응적 행동을 하려면 목표를 달성할 가능성이 적어질 때 스스로 계획을 수정하고 이러한 방식으로 수정되는 방법을 계속적으로 학습하여 차후 같은 경우에는 학습이 반영된 더 좋은 계획 및 전술을 반영하도록 해야 한다. 즉, 목표와 현재의 상태를 실시간으로 분석하고 측정하여 목표 달성도를 정량적으로 계산하고 측정값이 임계값보다 적으면 수정된 계획을 선택하도록 하는 것이다. 본 논문에서는 위와 같이 에이전트가 목표 달성 가능성이 적어질 때 적응적으로 계획을 새롭게 수정하여 적용하는 방법을 연구한 목적 지향적 행위계획 방법을 제안한다.

• 해양환경안전학회지
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• 제12권1호
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• pp.47-52
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• 2006

최근 국내 선박충돌사고는 전체 해양사고의 약 $20%{\sim}34%$를 차지하며, 그 구성비 또한 매년 증가하는 경향을 나타내고 있다. 따라서 본 연구는 선박충돌회피를 효과적으로 지원하기 위해, 선박충돌회피에 큰 영향을 주는 선박조종성능과 근접상황 충돌회피지원을 위해 연구된 CCAS-Model(Close Quarters ship Collision Avoidance Support Model . 근접상황 충돌회피지원모델)을 기반으로 한 선박충돌회피지원 프로그램 개발을 목적으로 수행 되었다. 이 프로그램은 선박의 다양한 조우상황을 비교하고, 자선의 선회특성을 이용하여 상대선박의 침로, 속도 유지에 대한 충돌회피 가능영역과 방법을 나타냄으로써 근접상황에서도 신속한 피항동작의 검토 및 결정을 가능케 하며 효과적인 충돌회피 조선을 지원할 것이다.

• 한국지반공학회논문집
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• 제28권9호
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• pp.31-45
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• 2012

본 연구에서는 월파시 해안안벽에 작용하는 지진과 지진해일의 영향에 대하여 한계평형상태해석법을 적용하여 안정성을 검토하였다. 지진해일파력에 대하여 TWOPM-3D를 적용하였으며, 특히 안벽의 뒷채움재를 투과성재료로 가정하여 지진해일파가 월파 후에 안벽배후에 작용하는 파력을 산정하였다. 그리고, 수동상태와 주동상태 조건에서 해안안벽의 안정성에 영향을 주는 요인인 지진해일파고, 뒷채움재의 수위, 수평 수직지진가속도계수, 내부마찰각, 벽마찰각, 간극수압비 등을 변화하여 활동과 전도에 대한 안벽 안전율의 변화특성을 시간에 따라 검토하였다. 이로부터 지진과 지진해일파의 작용하에 지진해일파가 안벽을 월파하는 경우 수동상태에 대한 안전율은 결과적으로 안전율을 증가시키는 요인으로 작용하는 반면, 주동상태에 대하여 결과적으로 안전율을 감소시키는 요인으로 작용함을 확인할 수 있었다.

• Journal of Construction Engineering and Project Management
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• 제1권3호
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• pp.18-27
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• 2011

Although information communication technology (ICT) is long regard as very useful tool in today's construction engineering and project management environment, organizations must not only operate based upon its original setting, but also requires on-going observation, additional features and fine-tuning actions before the desirable outcome can be achieved. However, it is a very common phenomenon that organizations purchase the licensed "off-the-shelf-software" package and customize it to suit their own business need. Due to the incapability of such software and inefficient customization, the possible result is making that ICT tool not user-friendly and sometimes the whole system becomes obsolete. The purpose of this paper is to review and report those actions taken (between February 2006 and December 2010) by a construction organization to enhance the performance of its Enterprise Resource Planning (ERP) system launched in December 2002. Such actions include: improving data inputting method; removing the transition bottleneck; introducing crystallization function; revising the organization's "Delegation and Limits of Authority"; publishing the "League Table" amongst users; integrating the 3D Mode into the system and upgrading hardware. Whilst the ultimate goals of such system are well beyond the time limit of this research study, an obvious interim result, achieved by this case studied organization, was winning a landmark project worth US$500 million after the ERP system was functioned properly and effectively. Their experience and success becomes an exemplar which can be borrowed by those companies, from managerial perspectives and as a roadmap, planning to adopt information technology (IT) strategy and use ICT tool in the construction engineering and project management framework. Singapore, where public housing provisions have been a major concern of their citizens as the building stock gets older.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.274-283
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• 2016

본 논문은 복잡해지는 군수분야에서 효율적이고 효과적인 예방정비업무 할당을 위해 Hard Time업무의 최적 주기산정 및 이를 통한 경제적 효용성을 분석하는데 연구 목적이 있다. 본 연구는 기존 연구에서 제시하는 예방정비 주기 선정방법의 한계점을 분석하였다. 또한 일반적인 Wearout 고장 특성을 설명하는 와이블 수명분포에서 다양한 형상모수 조건과 예방정비비용과 고장정비비용 조건을 가정한 시뮬레이션을 통해 가상의 시스템에 대한 정비활동을 모의하여 총 정비비용의 추의를 분석하였다.

• 한국물환경학회지
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• 제29권6호
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• pp.762-776
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• 2013

Load duration curve was applied to determine important water quality parameter control term for improvement of Paldang lake water quality. Load duration curve was analyzed with long term data from 1985 to 2012 including water quality, flow rate and climate state of Paldang water environment. From the result of flow rate patterns of paldang lake, differences between high and low flow rate of each year showed tendency of increase because rainfall characteristics of paldang lake watershed were changed by climate exchange. Both of land use state of upper Paldang lake watershed and number of limit excess from load duration curve indicated that seasonal action related with land use such as agricultural fertilizer distribution in upper watershed affected Paldang lake water quality. So focused BOD (biological oxygen demand) management during spring season from march to June is required to control organic materials in Paldand lake. The main affecting factor of TOC (total organic carbon) increase in Paldang lake was initial rainfall after march. T-N (total nitrogen) kept increasing during research period, so enhancement of T-N standard is needed to T-N control. Initial rainfall and increase of temperature during spring season from March to June showed a positive correlation with TP (total phosphorus) and Chl-a, respectively.

• 한국지능시스템학회논문지
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• 제19권5호
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• pp.674-682
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• 2009

모듈러 로봇은 기존 이동용 로봇이 가지는 공간 이동의 제한성을 극복하기 위해 개발된 로봇이다. 특히 체인형 로봇은 서로 직렬로 결합이 되어 있어 형체 표현방법이 간단하고 결합방법이 실제로 구현하기가 쉽다. 하지만 모듈러 로봇 관련 연구는 결합을 이용한 움직임 구현에 초접을 두어 독립적인 셀의 움직임은 이루어지지 않으며 모든 면에서 결합하지 못하고 한쪽 방향으로만 결합할 수 있는 등의 문제를 가지고 있다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해서 신속하고 독립적인 이동을 위한 바퀴구조의 모률을 기구에 실장 시켜 스스로의 자율성을 갖게 하였다. 또한 독특한 고정 기어 구조를 적용해 1개의 고정 모터로 2개의 모률을 결합할 수 있게 기구를 설계하여 기구의 효율성을 추구하였다. 이를 위해 본 논문에서는 기구 구조를 제안하고 이를 통작하기 위한 제어 회로에 대한 내용을 다루었으며, 모률간의 결합을 위한 고정 알고리즘과 통신 구조를 설계하였다. 아울러 제작된 프로타입은 실제의 응용예제를 통해 구조의 유용성을 검증하였다.

• Membrane and Water Treatment
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• 제13권6호
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• pp.303-312
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• 2022

The natural hydrology and geological conditions of Xintian County was investigated, the development law of regional karst fissures was studied, the groundwater was collected and tested through a large-scale collection of groundwater to obtain the change law of chemical characteristics and water quality characteristics of groundwater, and the water quality evaluation was carried out for the regional karst groundwater in this paper. The results show that, the whole area is dominated by carbonate rock distribution areas, and the distribution of water systems is relatively developed. The strata are distributed from the Lower Paleozoic Cambrian to the Cenozoic Quaternary, and contain multiple first-order folds. The regional karst dynamic action is strong, and many tunnels or caves of different scales were shown, which are conducive to the enrichment of groundwater. Karst groundwater is neutral and alkaline water, the water is clear and transparent with good taste, and meets the national drinking water hygiene standards. The content of toxic trace elements and fluoride in the water source is generally lower than the limit value specified by the national standard and the accumulated toxic heavy metals is never found. The overall water quality is of good quality and suitable for the development and utilization of various purposes.