• 제목/요약/키워드: far-field environment

검색결과 194건 처리시간 0.026초

가려진 동적 장애물을 고려한 이동로봇의 안전한 주행기술개발 (Safe Navigation of a Mobile Robot Considering the Occluded Obstacles)

  • 김석규;정우진
    • 제어로봇시스템학회논문지
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    • 제14권2호
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    • pp.141-147
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    • 2008
  • In this paper, we present one approach to achieve safe navigation in indoor dynamic environment. So far, there have been various useful collision avoidance algorithms and path planning schemes. However, those algorithms have a fundamental limitation that the robot can avoid only "visible" obstacles. In real environment, it is not possible to detect all the dynamic obstacles around the robot. There exist a lot of "occluded" regions due to the limitation of field of view. In order to avoid possible collisions, it is desirable to consider visibility information. Then, a robot can reduce the speed or modify a path. This paper proposes a safe navigation scheme to reduce the risk of collision due to unexpected dynamic obstacles. The robot's motion is controlled according to a hybrid control scheme. The possibility of collision is dually reflected to a path planning and a speed control. The proposed scheme clearly indicates the structural procedure on how to model and to exploit the risk of navigation. The proposed scheme is experimentally tested in a real office building. The presented result shows that the robot moves along the safe path to obtain sufficient field of view, while appropriate speed control is carried out.

만성통증의 경감과 치유를 위한 노인요양시설의 긍정적 관심 전환 환경 (Nursing Home Environment with Positive Distraction for Reduction of Chronic Pain and Healing)

  • 정미렴
    • 한국실내디자인학회논문집
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    • 제24권2호
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    • pp.206-216
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    • 2015
  • Majority of the seniors living in nursing homes suffer from persistent chronic pain, which may cause depression and compromised quality of life if untreated. The environment should support them to lift their focus from current pain and worries to the positive feelings and the delight of life. The purpose of this research is to classify the healing environment elements for positive distraction, and analyze 6 international cases to see the current situation. The elements were categorized as follows, based on literature review from both healing spaces and elderly care field: spatial elements(view, natural elements, artificial elements, exercise space, garden), psychological elements(grooming area, space for privacy, meal/drink area, elements for recollection, religious space), social elements(common living area, activity/hoppy room, family/visitor area, information area, local community program space). Analysis on 6 facilities showed that each elements were reflected to designed relatively well. New inventions from workers who think distraction is important were also introduced. Healing environment for positive distraction requires delicate touch, derived from understanding characteristics and situation of the residing elderly individuals. Technology update is also significant, from audio books to virtual reality devices, since cultural life of nursing home is far behind from what the others enjoy now.

SIL 헤드유사 근접장 시스템 개발을 위한 보호막 설계 및 열해석 (Cover Layer Design and Temperature Analysis in Pseudo NFR System Using SIL Head)

  • 김경호;김수경;이성규;박강호;이승엽
    • 정보저장시스템학회논문집
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    • 제1권1호
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    • pp.58-66
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    • 2005
  • Pseudo-Near Field Recording (Pseudo-NFR) system is proposed to prevent contamination and oxidation of media surface occurred in conventional NFR systems. To solve these critical problems of the NFR systems, we investigate the optimal thickness of cover layer for Pseudo NFR. This paper presents the theoretical analysis for cover layer thickness based on the measured length of dust particle and numerical simulation for the temperature distribution using Finite Difference Time Domain (FDTD) method and heat conduction equation. To verify the simulation results, we conduct and compare simulation results in case of far field MO recording and near field MO recording. A measured dust particle length in general environment was mostly less than $20{\mu}m$, and the optimal thickness of cover layer is $30{\mu}m$ in this case. Based on the designed optimal cover layer thickness, temperature distribution is simulated to have $800{\~}850^{\circ}C$.

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외국식물의 배치변화에 따른 폼알데하이드와 VOCs 농도저감에 관한 연구 (A Study on the Reduction of Formaldehyde and VOCs by Positions of Foreign Plants)

  • 송정은;김용식;손장열
    • KIEAE Journal
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    • 제8권2호
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    • pp.53-58
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    • 2008
  • With architectural technology, a building has been a far dense and close. So the thermal environment of the building has become pleasant, but the quality of indoor air has been degraded. Using synthetic products for construction materials and furniture indoors escalates the concentration of volatile organic compounds(VOCs) at indoor air, threatening the health of the residents. To reduce the concentration of volatile organic compounds at indoor air, many methods are designed, and of late, concern has been increased about the effect of air purification using air purifying plants. Field measurements were performed using Aglaonema brevispathum, Pachira aquatica and Ficus benjamiana, which were verified as air-purifying plants by NASA. The effect of reducing the concentration of air contaminants by plant studied in a full scale mock-up model. The variations of concentration of Benzene, Toluene, Ethylbenzene and Formaldehyde were monitored. In most cases, the effect was excellent in Toluene and formaldehyde in summer.

마이크로 컴퓨터를 이용한 항만설계 시뮬레이터의 영상정보 신뢰성에 관한 연구 (On the Visual Scene Validity of the Microcomputer Aided Port Design Simulator)

  • 김환수
    • 해양환경안전학회지
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    • 제3권2호
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    • pp.1-12
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    • 1997
  • One of the main uses for ship simulators is in the field of port design, and an increasing number of simulators, of varying degrees of fidelity, are being used for this purpose. An essential feature of all such simulators is their visual scene, which must be of sufficent fidelity to convey the key visual cues adequately. This paper examines the ability of a number of experienced mariners to perceive speeds and distances correctly using Computer Generated Imagery visual scenes of different fidelity, compared with their performance at sea. From the results, it was found that the microcomputer based simulator might be considered, as far as its visual scene representation is concerned, to be as valid as the full mission ship simulator for the port design task.

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Prediction and analysis of structural noise of a box girder using hybrid FE-SEA method

  • Luo, Wen-jun;Zhang, Zi-zheng;Wu, Bao-you;Xu, Chang-jie;Yang, Peng-qi
    • Structural Engineering and Mechanics
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    • 제75권4호
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    • pp.507-518
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    • 2020
  • With the rapid development of rail transit, rail transit noise needs to be paid more and more attention. In order to accurately and effectively analyze the characteristics of low-frequency noise, a prediction model of vibration of box girder was established based on the hybrid FE-SEA method. When the train speed is 140 km/h, 200 km/h and 250 km/h, the vibration and noise of the box girder induced by the vertical wheel-rail interaction in the frequency range of 20-500 Hz are analyzed. Detailed analysis of the energy level, sound pressure contribution, modal analysis and vibration loss power of each slab at the operating speed of 140 km /h. The results show that: (1) When the train runs at a speed of 140km/h, the roof contributes more to the sound pressure at the far sound field point. Analyzing the frequency range from 20 to 500 Hz: The top plate plays a very important role in controlling sound pressure, contributing up to 70% of the sound pressure at peak frequencies. (2) When the train is traveling at various speeds, the maximum amplitude of structural vibration and noise generated by the viaduct occurs at 50 Hz. The vibration acceleration of the box beam at the far field point and near field point is mainly concentrated in the frequency range of 31.5-100 Hz, which is consistent with the dominant frequency band of wheel-rail force. Therefore, the main frequency of reducing the vibration and noise of the box beam is 31.5-100 Hz. (3) The vibration energy level and sound pressure level of the box bridge at different speeds are basically the same. The laws of vibration energy and sound pressure follow the rules below: web

특이섭동법을 이용한 비행체 자동착륙 유도제어 알고리즘 설계 (Design of Autolanding Guidance and Control Algorithm Using Singular Perturbation)

  • 하철근;최형식
    • 제어로봇시스템학회논문지
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    • 제11권8호
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    • pp.726-732
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    • 2005
  • This paper proposes an autolanding guidance and control algorithm with the lateral guidance law. This algorithm is basically formulated and designed in feedback linearization based on singular perturbation. Main features of this algorithm are two facts. One of those is that when a certain situation happens that airplane must realign to the runway suddenly assigned due to unexpected environment change around the landing site, the heading guidance in this algorithm is very valuable, and the other is the fact that the inner loop control of this algorithm is able to be designed directly based on the Handling Quality Requirements that most flight control systems must be satisfied with. To illustrate the potential of this algorithm, 6-DOF nonlinear simulation based on the nonlinear airplane model shown in Ref.[11] is carried out. The simulation results showed that the altitude response to the given landing trajectory is accurate, and the airplane heading alignment to the assigned runway from the lateral deviation is successful. It is noted that this algorithm is also applicable to unmanned aerial vehicle, which can be retrieved in autolanding technique, where the runway far retrieving the vehicle is in any direction for example at war field.

간호조무사의 근무환경인식과 성격성향에 관한 연구 (A Study on the Working Environment Recognition and the Caracter Disposition of Nurse Aides)

  • 이선이
    • 한국보건간호학회지
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    • 제4권1호
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    • pp.57-74
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    • 1990
  • As the whole world took on the tendency to be highly industrialized, it became necessary for each field of occupation to require professional man power. Especially, since the World War n, the participation of woman power in economic activities has been continually increasing. In our country also, because of the rapid economic growth, change in the way of thinking of women as well as their participation in economic activities are increasing. Thus, woman power is being utilized in various occupational fields from simple physical labor to those that require high-professional skill. Also, continued economic development policies, by setting the establishment of welfare society as the ideology to be fulfilled, brought expansion of medical facilities in the field of public health and increase in man power in that field. As for the nursing specialists, more than 6000 have been being produced per year and as of the end of 1988, the total number of nursing specialists, reached 123, 115. Therefore, this study is done to recognize the professional knowledge and ability of nursing specialists, who take up $40\%$ of the total public-health related man power in our country, through evaluating their working environment and their disposition of character. This study, which was done from September 18th to September 30th 1989, took on the method of using formed questionnaires that had been amended and supplemented during two preparatory investigations, 322 of such questionnaires were used as an analytical material. In the formation of questionnaires, 12 questions were related to the working environment, and 26 in fortotal were related to the disposition of character, 5 for wise-disposition, 11 for activedisposition and 10 for open-disposition. The measuring method, which used 5-point-standard, allowed 5 points for affirmative recognition of the working environment, also 5 points for showing wise, active and open disposition of character and only point in opposite cases. Collected materials were analyzed, through an electronic calculation, into the average value, the standard deflection percentage, pearson corelative number and stepwise multiple regression. Summarizing the results from this study is as follows: 1. It was shown that the nursing specialists with the average of 3.07 have affirmative recognition of their working environment. The questions which drew most affirmative reaction were those concerning finance-management system such as hand, the questions that received negative reaction were those concerning communication method with the average of 2.49. Such reaction seems to have resulted from the cramming regulation by the superior authorities. Concerning the recognition of working environment in relation to employment conditions, more affirmative recognition is shown with the average of 3.14. at hospitals where injection job is not performed. The nursing specialists working at regular hospitals show more affirmative recognition than those at general hospitals, the averages being respectiely 3.16 and 3.03. 2. As for the disposition of character of the nursing specialists, active-disposition was highest with the average of 3.38, next was wise-disposition with 3.20 and the lowest was open-diposition with 2.98. Variable-wise disposition of character shows that wise-disposition and academic background are beneficially correlated by 0.12. Ative-disposition and open-disposition show correlation to the office term by respectively 0.16 and 0.21. In other words. better academic background leads to higher wise-disposition and more - experience results in higher active and open disposition. Also, the class that performs the injection job, in relation to the working environment, might cause change in the self-conceit that identify those in that class with the nurses; however, as far as professional judgment and action, in dealing with nursing job, being wise, active and open is concerned, not much effect is made. 3. The relation between the recognition of the working environment and the disposition of character is that more afirmative recognition- a nursing specialist has about her working environment, the higher the active-disposition becomes by 0.13. The degrees of the relation between recongnition of environment and wise and open dispositions show respectively 0.06 and -0.06 and -0.06. That is to say that when having more affirmative recognition of the working environment, a nursing specialist shows wise but closed disposition of character. This, howerver, didn't mean much statistically. When observing the results mentioned above, it is conspicuous that the nursing specialists, working as substitutes for the nurse at medical institutions of various sizes, get the feeling of being somewhat equal to the nurses and to some extent, fulfill their desire to accomplish their ego; however, as far as professional ability expansion if concerned. they lack wise and open dispositions. Therefore, considiering upon the results of this study, in medical institutions where the work of nursing specialists is regaded equal to that of the nurses, as a medical member who deals with human lives, it is desirable to make the nursing specialists work under the supervision of the nurses and to offer them continuous education to strengthen and improve their natural dispositions.

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해운 및 항만운송에 적용된 의사결정분석에 관한 연구 (The Literature Survey on the Applied Decision Analysis to Shipping and Port Transportation)

  • 김시화
    • 한국항해학회지
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    • 제12권1호
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    • pp.113-136
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    • 1988
  • Decision Science or Decision Analysis can be described as a scientific methodolog to provide suitable quantitative information for the decision maker to be able to selected the best feasible alternative on the given decision environment and thus we can say that where there are decision problems, there needs the decision analysis to be applied to them. International shipping is generally said to be the cheapest and most widely used means of transport in international trade and each of the hundreds of seaport. So far as the decision makings in the shipping and port transportation are concerned, of real importance is to understand what the decision problems in each of shipping and port transportation really are and to recognize the meaning of relevance between shipping and seaport in the outworn phrase, that is to say, "The chain is as strong as its weakest link." This paper is intended to present a literature survey on the applied decision analysis to shipping and port transportation problems which have actually been involved in the wide variety of decision environment. At first, the author suggests four divisional framework such as decision analysis in each field of Shipping Economics, Management and Operations of Shipping, Port Economics, and Port Operation and Management, according to the main concern of the decision environment, and then the literature surveys on those four major divisions are described including the problems and solution approaches in each case. The author concludes the paper with the comment on the need of joint research around this area by citing the phrase of "a process of updating the decision makers' intuitions."s' intuitions."quot;

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Development of a Computer Code for Low-and Intermediate-Level Radioactive Waste Disposal Safety Assessment

  • Park, J.W.;Kim, C.L.;Lee, E.Y.;Lee, Y.M.;Kang, C.H.;Zhou, W.;Kozak, M.W.
    • Journal of Radiation Protection and Research
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    • 제29권1호
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    • pp.41-48
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    • 2004
  • A safety assessment code, called SAGE (Safety Assessment Groundwater Evaluation), has been developed to describe post-closure radionuclide releases and potential radiological doses for low- and intermediate-level radioactive waste (LILW) disposal in an engineered vault facility in Korea. The conceptual model implemented in the code is focused on the release of radionuclide from a gradually degrading engineered barrier system to an underlying unsaturated zone, thence to a saturated groundwater zone. The radionuclide transport equations are solved by spatially discretizing the disposal system into a series of compartments. Mass transfer between compartments is by diffusion/dispersion and advection. In all compartments, radionuclides ate decayed either as a single-member chain or as multi-member chains. The biosphere is represented as a set of steady-state, radionuclide-specific pathway dose conversion factors that are multiplied by the appropriate release rate from the far field for each pathway. The code has the capability to treat input parameters either deterministically or probabilistically. Parameter input is achieved through a user-friendly Graphical User Interface. An application is presented, which is compared against safety assessment results from the other computer codes, to benchmark the reliability of system-level conceptual modeling of the code.