• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.69-72
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• 1996

This paper considers a global resolution of kinematic redundancy under inequality constraints as a constrained optimal control. In this formulation, joint limits and obstacles are regarded as state variable inequality constraints, and joint velocity limits as control variable inequality constraints. Necessary and sufficient conditions are derived by using Pontryagin's minimum principle and penalty function method. These conditions leads to a two-point boundary-value problem (TPBVP) with natural, periodic and inequality boundary conditions. In order to solve the TPBVP and to find a global minimum, a numerical algorithm, named two-stage algorithm, is presented. Given initial joint pose, the first stage finds the optimal joint trajectory and its corresponding minimum performance cost. The second stage searches for the optimal initial joint pose with globally minimum cost in the self-motion manifold. The effectiveness of the proposed algorithm is demonstrated through a simulation with a 3-dof planar redundant manipulator.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.422-428
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• 2002

In this study, actuator, sensor, guide, power transmission element and control method are considered for ultra-precision positioning apparatus. Through previous process, single plane X-Y stage with ultra-precision positioning is manufactured. Global stage for the purpose of materialization with robust system, is combined by using AC servo motor and ball screw and rolling guide. And ultra-precision positioning system is developed by micro stage with elastic hinge type and piezo element. global servo and micro servo for the purpose of materialization positioning accuracy with nm(nanometer) are controlled simultaneously by using incremental encoder and laser interferometer as displacement measurement sensor. Through previous process, ultra-precision positioning system (100mm stroke and ${\pm}$ 10nm positioning accuracy) with single plane X-Y stage are materialized.

• 한국공작기계학회논문집
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• 제11권5호
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• pp.65-72
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• 2002

In this study, actuator, sensor, guide, power transmission element and control method are considered for ultra-precision positioning apparatus. Through previous process, single plane X-Y stage with ultra-precision positioning is manufactured. Global stage for the purpose of materialization with robust system, is combined by using AC servo motor and ball screw and rolling guide. And ultra-precision positioning system is developed by micro stage with elastic hinge type and piezo element. global servo and micro servo for the purpose of materialization positioning accuracy with nm(nanometer) are controlled simultaneously by using incremental encoder and laser interferometer as displacement measurement sensor. Through previous process, ultra-precision positioning system(100mm stroke and $\pm$ l0nm positioning accuracy) with single plane X-Y stage are materialized.

• IEIE Transactions on Smart Processing and Computing
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• 제2권4호
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• pp.189-196
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• 2013

This paper presents a two-stage approach to detect pedestrians in video sequences taken from a moving vehicle. The first stage is a preprocessing step, in which potential pedestrians are hypothesized. During the preprocessing step, a difference image is constructed using a global motion estimation, vertical and horizontal edge maps are extracted, and the color difference between the road and pedestrians are determined to create candidate regions where pedestrians may be present. The candidate regions are refined further using the vertical edge symmetry features of the pedestrians' legs. In the next stage, each hypothesis is verified using the integral channel features and an AdaBoost classifier. In this stage, a decision is made as to whether or not each candidate region contains a pedestrian. The proposed algorithm was tested on a range of dataset images and showed good performance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.348-352
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• 2002

a basis such as IT(Information Technology), NT(Nano Technology) and BT(Bio Technology). Recently, NT is applied to various fields that are composed of science, industry, media and semiconductor-micro technology. It has need of IT that is ultra-precision positioning technology with strokes of many hundreds mm and maintenance of nm precision in fields of ultra micro process, ultra precision measurement, photo communication part and photo magnetic memory. This thesis represents optimal design on ultra-precision positioning with single plane X-Y stage and development of artificial control system for adequacy of industrial demand. Also, dynamic simulation on global stage is performed by using ADAMS (Automated Dynamic Analysis of Mechanical System) for the purpose of grasping dynamic characteristic on user designed X-Y global stage. The error between displacements from micro stage and from FEM(Finite Element Method) is 3.53% by verifications of stability on micro stage and control performance. As maximum Von-mises stress on hinge of micro stage is 5.981kg/mm$^2$ that is 1.5% of yield stress, stability on hinge is secured. Preparing previous results, optimal design of micro stage can be possible, and reliance of results with FEM can be secured.

• 품질경영학회지
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• 제45권1호
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• pp.65-92
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• 2017

Purpose: The performance of global major airports is evaluated and several research questions are examined relative to the measures characterizing airport performance. Methods: The two-stage internal structure of airport performance is considered by decomposing it into physical operations and revenue generation. In the physical operations stage, operating costs, number of runways, terminal area and number of employees are used as inputs, while passenger throughput, cargo throughput and aircraft movements are taken as outputs. Subsequently, in the revenue generation stage, the outputs from the preceding stage are taken as inputs, while revenue is used as output. Results: Based upon this two-stage modeling of airport performance, a multiplicative two-stage network data envelopment analysis model is employed to calculate the overall and stage efficiencies of 59 airports using the recent data in the 2014 Airport Benchmarking Report published by the Air Transport Research Society. Several internal and external factors are also considered such as airport size, airport geographical location, proportion of international passengers, ownership (listed or not) and management style, and statistical analysis is performed to examine their impacts on airport performance. Conclusion: It is shown that the airports exhibit statistically significant difference across regions, and also some statistically significant factors affecting airport performance are identified.

• 한국항만경제학회지
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• 제25권2호
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• pp.301-318
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• 2009

전 세계적으로 우편의 비중은 줄어들고 특송 및 물류서비스에 대한 수요는 지속적으로 증가하는 추세에 있다. 최근 우리나라 우정사업본부는 통상우편물의 정체, 우체국예금, 보험의 성장률 둔화에 직면하고 있다. 따라서 본 논문에서는 DPWN의 사례분석을 통해 우리나라 우정사업본부의 물류기업화 방안을 제시하는 데 있다. 연구결과를 요약하면 다음과 같다. 첫째, 1단계로 물류사업 진출을 위해 조직개편이 선행되어야 한다. 즉 기존의 예금, 우편물, 보험에 물류회사를 설립하는 것이다. 둘째, 2단계로 기존 사업영역에 보관물류 및 복합운송물류 부문 강화를 위해 상호 보완성과 시너지 효과가 있는 대상 기업의 인수나 출자를 통해 종합물류업체로서의 사업영역을 구축하는 것이다. 셋째, 3단계로 중국, 인도 등 물류수요가 많거나 물류시장 규모가 큰 지역을 중심으로 외형을 확대하고 서비스 영역을 확장하는 것이다. 넷째, 4단계로 글로벌 중심의 통합물류서비스를 제공하는 단계로 유럽, 미주를 중심으로 글로벌 네트워크 확장을 위해 인수 합병, 현지법인, 합작회사 및 전략적 제휴 등을 적극적으로 추진하는 것이다. 본 논문의 한계점으로 우정사업본부의 물류산업 진출에 대한 선행연구의 부족으로 우정사업본부의 글로벌 물류기업화와 관련해서 보다 심층적인 전략과 방안이 제시되지 않았다는 것이다. 향후, 이러한 한계점을 개선하고 보완할 수 있는 보다 심층적이고 실증적인 연구가 수행되어져야 할 것이다.

• 한국지역지리학회지
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• 제19권3호
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• pp.551-565
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• 2013

이 연구는 오스트레일리아 NSW 주 지리 교육과정과 이에 근거하여 개발된 지리교과서에 나타난 개발교육을 분석한 것이다. 지리 교육과정 및 교과서에 나타난 개발교육의 특징을 분석한 결과는 다음과 같다. 먼저, 지리 교육과정에서 Stage 4와 Stage 5의 필수 지리는 개발교육을 구체적으로 명시화하지 않고 삶의 질의 차이와 원조 연계를 통해 개발교육에 접근하고 있는 반면, 심화 과목인 선택 지리의 경우 개발교육을 명시화하고 있다. 뿐만 아니라 Stage 6에서도 개발지리를 구체적으로 명시하여 보다 심화하여 학습하도록 하고 있다. 다음으로, 지리 교과서에서는 개발교육이 개발에 대한 학습에서 바로 시작하는 것이 아니라 일상생활에서의 삶의 질의 차이를 선행하여 학습한 후 개발 및 개발 척도를 다양한 관점에서 균형있게 이해하도록 하고, 이러한 글로벌 불평등 해소를 위해 개인 또는 조직으로서 어떻게 행동하고 실천해야 할 것인가에 대한 학습으로 계열화되어 있다. 이러한 분석 결과를 통해 얻을 수 있는 함의는 다음과 같다. 첫째, 중등학교 저학년에서는 개발을 직접적으로 다루기보다는 이와 관련한 삶의 질의 차이를 중심으로 내용을 구성하고, 중등학교 고학년에서는 개발지리에 대해 직접 학습하도록 할 필요가 있다. 둘째, 개발교육에서 등장하는 주요 개념인 개발, 개발 척도, 원조 등의 의미를 다양한 관점에서 균형 있게 다룰 필요가 있다. 셋째, 개발교육은 우리나라와 다른 국가와의 구체적인 개발 연계 사례를 통해 추상적인 상호의존성이라는 개념과 글로벌 시민성이라는 가치를 학습하고 실천할 수 있도록 할 필요가 있다. 마지막으로 글로벌 불평등을 줄이기 위한 노력을 당위적인 측면에서 기술하거나 정부 및 비정부기구 등과 같은 조직의 차원에 한정하지 않고, 개인적인 실천 사례를 통해 그들의 가치와 행위를 감정이입하도록 할 필요가 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1153-1159
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• 2007

The vibration analysis is necessary at the design stage to improve crew's life on board and to prevent the vibration troubles of the hull structures and main machineries prior to the construction. Especially, if high vibration problems occur on the global structures like the hull girder and the deckhouse after construction, it takes lots of time, labor and cost to cure them and thus accurate analysis of global vibration should be performed from the design stage. In this study, some factors for the global vibration analysis have been investigated and the way to be applied to the analysis has been suggested.

• 한국소음진동공학회논문집
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• 제18권5호
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• pp.509-515
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• 2008

The vibration analysis is necessary at the design stage to improve crew's life on board and to prevent the vibration troubles of the hull structures and main machineries prior to the construction. Especially, if high vibration problems occur on the global structures like the hull girder and the deckhouse after construction, it takes lots of time, labor and cost to cure them and thus accurate analysis of global vibration should be performed from the design stage. In this study, some factors for the global vibration analysis have been investigated and the way to be applied to the analysis has been suggested.