• Title/Summary/Keyword: 작업영역분석

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The Rheology of Cement Paste Using Polycarboxylate-Based Superplasticizer for Normal Strength-High Fluidity Concrete (보통강도 고유동 콘크리트용 PC계 고성능 감수제를 사용한 시멘트 페이스트의 레올로지 특성 평가)

  • Kong, Tae-Woong;Lee, Han-Seung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.276-286
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    • 2021
  • General high fluidity concrete is the area of high strength concrete with a high amount of cement to secure the required fluidity and workability. Since most of the concrete structures currently used have normal strength, there is a limit to the practical expansion and practicality of use. Thus it is necessary to develop normal strength-high fluidity concrete with low binders that can be used not only in general buildings but also in special buildings, and can greatly reduce construction time and save labor costs. This requires to develop and apply the polycarboxylate-based superplasticizer. In this study, PCE was prepared for each combination of starting materials(WR, HB, RT) and the rheological properties of cement paste were analyzed using ringflow cone and a rotary viscometer. As a result, when PCE with a combination of WR 80%, HB 6.5%, and RT 13.5% was applied, the yield stress can be minimized while securing the plastic viscosity at level of the normal strength. In addition, high fluidity due to the high dispersion effect was confirmed.

A Study on the Efficient Tension Estimation of Cables under Ambient Vibration using Minimized Measurement and Signal Processing System (최소화된 계측 및 신호 처리 시스템을 이용한 상시진동 케이블의 효율적인 장력 추정에 관한 연구)

  • Lee, Hyeong-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.594-603
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    • 2018
  • Recently, according to the development of measurement techniques, it has become possible to take complicated and time-consuming field measurements in a simple and convenient manner. In this background, this study estimated the tension of cables under ambient vibration using minimized measurement and signal processing. The VBDM using video-only by low-cost equipment was used as a minimized measurement. An estimation of the natural frequency using the mirror frequency concept was also proposed to solve the shortage of frequency band in this case. Furthermore, the FDD method was adopted for a natural frequency estimation in the ambient vibration related to field application. Experimental studies using a cable-stayed bridge model were carried out to examine the properties of the mirror frequency and the applicability of FDD with the proposed minimized system. The results showed that FDD for ambient vibration also works properly in an estimation of the natural frequency using the minimized system. In addition, the mirror frequency concept can allow a high natural frequency estimation even in a distorted signal by low-speed recording, which can overcome the limit of the minimized system. Overall, the proposed minimized system can be effective for the tension estimations of a cable under ambient vibration.

Comparison of Demographic Characteristics, Health and Quality of Life between General Adults and Adults Living with Dementia Patients : The 2016 Community Health Survey (치매 환자와 함께 거주하는 성인과 일반 성인 사이의 인구사회학적 특성, 건강 및 삶의 질 비교 : 2016년 지역사회건강조사 원시자료를 이용하여)

  • Moon, Jong-Hoon;Kim, Ye-Soon
    • Journal of Society of Occupational Therapy for the Aged and Dementia
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    • v.12 no.2
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    • pp.57-65
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    • 2018
  • Objective : The purpose of this study was to compare the demographic characteristics, health and quality of life between general adults and adults living with dementia. Method : The data were collected using raw data of the 2016 community health survey and compared between 2,592 adults living with dementia patients and 225,840 general adults. health were assessed for sleep time, stress level, depression, and subjective health status, and quality of life was measured by EQ-5D. Result : In comparison of demographic characteristics, age and family number of adults living with dementia patients were significantly higher than general adults (p<.001), income and eduation levels were low (p<.001), and marital status was higher rate of living with spouse (p<.05). In comparison of health status, adults living with dementia patients were significantly longer in sleep time than the general adults (p<.001), and stress level was higher (p<.001), the percentage of experience of depression was higher (p<.001), and the subjective health status was worse (p<.001). Adults living with dementia patients were significantly lower in quality of life total score and all sub-domain than general adults (p<.001). Conclusion : Based on the results of this study, it is necessary to seek ways to improve the health and quality of life of dementia patients' families.

A Comparative Study of Sensory Processing Abilities and Visual Perception Skills in Children With Attention Deficit Hyperactivity Disorder and Typical Children (ADHD 아동과 일반 아동의 감각처리능력과 시지각 기술의 비교 연구)

  • Ju, Jin-Ok;Kim, Kyeong-Mi
    • The Journal of Korean Academy of Sensory Integration
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    • v.18 no.3
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    • pp.1-13
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    • 2020
  • Objective : The purpose of this study was to evaluate the differences in sensory processing and visual perception between school-age children with Attention Deficit Hyperactivity Disorder (ADHD) and typical children. Methods : The participants in this research were children in the first and second grade in elementary school in Kyoung-Nam Region; 25 children diagnosed with ADHD comprised the experimental group, and 51 typical children comprised the control group. To evaluate the sensory processing of the children, the Sensory Profile (SP) was used, and the Korean Developmental Test of Visual Perception-2 (K-DTVP-2) was used to assess visual perception skills. The data were analyzed using SPSS 20.0, and the Independent t-test was used to compare the sensory processing and visual perception skills of the two groups. Results : The study found differences in the Sensory Profile summary scores and factor summary scores between the two groups (p<.05). We also found differences in the visual perception index and subtest standard scores between the two groups (p<.05). Conclusion : The results of this study show that the experimental and the control groups had significant differences in sensory processing and visual perception skills. The result will contribute to the assessment and education of children with ADHD.

A Feasibility Study in Forestry Crane-Tip Control Based on Kinematics Model (1): The RR Manipulator (기구학적 모델 기반 임업용 크레인 팁 제어방안에 관한 연구(1): RR 매니퓰레이터)

  • Kim, Ki-Duck;Shin, Beom-Soo
    • Journal of Korean Society of Forest Science
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    • v.111 no.2
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    • pp.287-301
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    • 2022
  • This study aims to propose a crane-tip control method to intuitively control the end-effector vertically or horizontally for improving the crane work efficiency and to confirm the control performance. To verify the control performance based on experimental variables, a laboratory-scale crane was manufactured using an electric cylinder. Through a forward and reverse kinematics analysis, the crane was configured to output the position coordinates of the current crane-tip and the joint angle at each target point. Furthermore, a method of generating waypoints was used, and a dead band using lateral boundary offset (LBO) was set. Appropriate parameters were selected using bang-bang control, which confirmed that the number of waypoints and LBO radius were associated with positioning error, and the cylinder speed was related to the lead time. With increased number of waypoints and decreased LBO radius, the positioning error and the lead time also decreased as the cylinder speed decreased. Using the proportional control, when the cylinder velocity was changed at every control cycle, the lead time was greatly reduced; however, the actual control pattern was controlled by repeating over and undershoot in a large range. Therefore, proportional control was performed by additionally applying velocity gain that can relatively change the speed of each cylinder. Since the control performed with in a range of 10 mm, it was verified th at th e crane-tip control can be ach ieved with only th e proportional control to which the velocity gain was applied in a control cycle of 20 ms.

Cultural Horizon of Freedom (자유의 문화적 지평)

  • Kwon, Su Hyeon
    • Journal of Ethics
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    • no.76
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    • pp.305-329
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    • 2010
  • The problem of freedom is inseparably related to human life. It makes this not to be regarded as a problem restricted to the professional domain of ethics. It suggests rather that the problem of freedom is intimately connected with the philosophical groundwork for discussing the future direction of society, culture and science, and its regulative idea, a philosophical discussion which comes up inevitably with various social, economic and political problems, and problems related to the spirit of law. In this view, when we want to explain the problem of freedom as a fundamental one in reference to future direction of humanities and to find out a solution to this, our research only in accordance with the approach of history of philosophy runs into difficulties. The reason is that the problem of freedom has nowness together with historicity. Finding this problem to be a present one in our concrete human life, we can discuss it more meaningful under the methodological frame changed and developed by philosophical reflections since the modern age. And here I think a culturalistic approach reinterpreting hermeneutic insight and pragmatistic context methodologically can provide a pertinent clue for a theoretical work to investigate the problem of freedom and to find a solution to that because this approach considers historicity and nowness. For this purpose analysing truth intersubjectively and understanding freedom critically, this article tries to reconstruct symbolic interpretation and the concept of self constructed in community of language and action as a cultural horizon of freedom.

A Study on the Transport-related Impacts of Flexible Working Policy using Activity-Based Model (활동기반모형을 이용한 유연근무제의 교통부문 영향 연구)

  • CHO, Sung-Jin;BELLEMANS, Tom;JOH, Chang-Hyeon;CHOI, Keechoo
    • Journal of Korean Society of Transportation
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    • v.35 no.6
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    • pp.511-524
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    • 2017
  • This study aims to evaluate the availability of ABM (Active-Based Model), FEATHERS, as a policy evaluation tool. To achieve the goal, scenario analysis on flexible working policy was conducted to measure its impact on activity-travel behavior. As a consequence, there seems no significant change in worker's daily life, other than mitigating traffic congestion due to decreasing commuting travel in the rush hour. The result of VKT (vehicle kilometers traveled) shows an opposite pattern according to given household/individual constraints. The scenario analysis on telecommuting indicates a decreasing trend in both travel frequency and distance because of the diminished number of commuting trips. As the activity space of telecommuters is shifted to a residential area, there are more short-distance trips by using non-motorized transport, which leads to decrease in VKT (using a private vehicle). Thus, the sensitivity of VKT by population groups varies due to transport mode shift (between personal and another mode) and growing non-work trips (using a private mode). This study found few things. First, it is necessary to evaluate the details of policy impact by population groups since it can be varied depending on household/individual characteristics. Second, the case study shows a promising performance of ABM as policy measurement that provides reality in policy evaluation. Third, ABM allows us to do more accurate analysis (i.e. time-series analysis by population groups) of policy assessment than those of FSM (Four-Step Model). Lastly, a further effort in data collection, literature review, and expert survey should be made to enhance the accuracy and confidence of future research.

Business Model of Data Service in Broadcasting and Communication Convergence (유비쿼터스시대 방송과 통신의 컨버전스 데이터 서비스 비즈니스 모델)

  • Jung, Chang-Duk;Lee, Ji-Eun
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2006.11a
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    • pp.245-249
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    • 2006
  • 디지털 컨버전스와 유비쿼터스 시대의 시작은 디지털 미디어 기술의 발전과 방송 통신 사업의 컨버전스를 가속화 시켰으며, 그 결과로DMB, WCDHA, Wibro, IP-TV, HSDPA 등의 새로운 형태의 차세대 제품과 서비스들이 뉴미디어 매체의 핵심으로 등장하고 있다. 국내에서 방송 통신의 컨버전스의 빠른 진행은 세계 최초로 디지털 멀티미디어 방송(DMB) 서비스 시작을 가능하게 하였다. DMB 서비스는 멀티미디어 서비스가 핵심이다. DMB 데이터 서비스인 Broadcasting Website Service(BWS)는 현재 지상파 DMB방송 사업자인 KBS, MBC, SBS, YTNDMB가 본방송 준비 막바지 단계이며, 삼성 전자와 LG전자를 비롯한 단말기 개발사들도 데이터 서비스를 위한 제품 출시에 서두르고 있는 등 DMB 산업의 활성화의 주역이 될 것으로 예상된다. DMB의 데이터 서비스는 뉴스, 날씨, 프로그램 정보 등의 단순 정보보기 수준에 그치지 않고, 리턴 채널을 이용한 양방향 서비스와, SMS, 전화걸기 등 휴대전화 단말의 고유기능과의 연계를 통한 다양한 서비스도 선보일 것이다. 더 나아가 향후 T-Commerce와 개인 광고 등 새로운 비즈니스 모델과 사업영역으로 확산시켜 나갈 수 있을 것이다. 그러나, 아직까지 DMB와 데이터 서비스는 초기단계로서, 표준 기술의 규격 작업, 이론적 논의들, 관련 사업자들의 비즈니스 준비 등에서 검토되어, 실제 사용자들을 대상으로한 연구 분석이 이루어 지지 않았다는 연구의 한계를 가지고 있다. 본격적으로 방송, 통신 컨버전스 데이터 서비스가 시작되면서, 사용자들에 초점을 맞춘 많은 연구가 이루어지길 바라며, 이러한 연구의 분석를 통해 또 다른 새로운 서비스와 비즈니스 기회의 창출을 기대해 본다.여 RD(Rate Distortion) 최적화 기반 모드 결정을 빨리 완료함으로써 고속 프레임간 모드 결정을 가능하게 한다. 제안된 방법은 프레임 간 모드 결정을 고속화함으로써 스케일러블 비디오 부호화기의 연산량과 복잡도를 최대 57%감소시킨다. 그러나 연산량 감소에 따른 비트율의 증가나 화질의 열화는 최대 1.74% 비트율 증가 및 0.08dB PSNR 감소로 무시할 정도로 작다., 반드시 이에 대한 검증이 필요함을 알 수 있었다. 현지관측에 비해 막대한 비용과 시간을 절약할 수 있는 위성영상해석방법을 이용한 방법은 해양수질파악이 가능할 것으로 판단되며, GIS를 이용하여 다양하고 복잡한 자료를 데이터베이스화함으로써 가시화하고, 이를 기초로 공간분석을 실시함으로써 환경요소별 공간분포에 대한 파악을 통해 수치모형실험을 이용한 각종 환경영향의 평가 및 예측을 위한 기초자료로 이용이 가능할 것으로 사료된다.염총량관리 기본계획 시 구축된 모형 매개변수를 바탕으로 분석을 수행하였다. 일차오차분석을 이용하여 수리매개변수와 수질매개변수의 수질항목별 상대적 기여도를 파악해 본 결과, 수리매개변수는 DO, BOD, 유기질소, 유기인 모든 항목에 일정 정도의 상대적 기여도를 가지고 있는 것을 알 수 있었다. 이로부터 수질 모형의 적용 시 수리 매개변수 또한 수질 매개변수의 추정 시와 같이 보다 세심한 주의를 기울여 추정할 필요가 있을 것으로 판단된다.변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에

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Comprehensive Diagnosis and Improvement Plans on Agricultural Production Cost Survey Statistics (농축산물생산비조사 통계의 종합적 품질 진단 및 개선 방안)

  • Koo, Seung-Mo;Kim, Sounghun;Lee, Kay-O;Sohn, Chang-Soo;Han, Suk-Ho
    • Journal of agriculture & life science
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    • v.45 no.6
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    • pp.291-301
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    • 2011
  • This study is based on the diagnosis process on agricultural production cost survey, which is one of the most representative public statistics of agricultural sector in Korea. The diagnosis were performed by employing the quantitative and qualitative approaches with the official guideline provided by the Ministry of Statistics. The various results were produced from the aspects of exactness, relevance, timeliness, accessibility, and comparability, which were based on the qualitative approaches including focus group interview (FGI) with professional users. The results from statistical portfolio analysis implies that the first priority to improve the statistics is given to 'satisfaction level corresponding to user cost' and 'offering sufficient explanation'. The comprehensive results, discussed with the administrative office, are summarized into the following two major points. First, classification of the detailed items should be improved to avoid users' confusion. However, the re-classification need to be professionally reviewed with the relevant administrative office such as Rural Development Administration, producing similar statistics. Second, the KOSIS system is found to be constantly upgraded to improve the users' convenience.

Verifying the Reliability and Validity of the Yonsei Lifestyle Profile for Adolescents (청소년을 위한 연세 라이프스타일 프로파일(Yonsei Lifestyle Profile)의 신뢰도 및 타당도 연구)

  • Kim, Ah-Ram;Lim, Young-Myoung;Park, Ji-Hyuk
    • Therapeutic Science for Rehabilitation
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    • v.13 no.2
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    • pp.41-51
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    • 2024
  • Objective : This study aimed to assess the applicability of the Yonsei Lifestyle Profile (YLP), initially developed for adults, for adolescents and verify its reliability and validity. Methods : This study evaluated the reliability and validity of the YLP among 436 middle and high school students in South Korea. The internal consistency of this scale was analyzed using Cronbach's alpha and Spearman-Brown's coefficient. Concurrent validity was assessed using Pearson's correlation coefficient with the Korean Youth Physical Activity Questionnaire, the Korean version of the Children and Adolescents Participation Scale, and the Nutrition Quotient for Adolescents. Results : The overall internal consistency of the YLP items demonstrated high reliability, with a Cronbach's α of .811 and Spearman-Brown's coefficient of .779. Significant positive correlations were observed for physical activity (r=.555, p<.01), activity participation (r=.177, p<.01), and dietary habits (r=.633, p<.05), indicating consistent correlations with the related scales. Conclusion : This study analyzed the YLP targeting adolescents and confirmed its high reliability and significant validity in the areas of physical activity, activity participation, and dietary habits. These findings suggest that the YLP can be utilized as a reliable tool for evaluating healthy lifestyles among adolescents.