• 한국수학교육학회지시리즈A:수학교육
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• 제29권1호
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• pp.21-34
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• 1990

This is a study on an instruction of estimation for error correction in the calculation with a computer or a calculator. The aim of this study is to survey a new aspect of calaulation teaching and the teaching strategy of estimation and finally to frame a new curriculum model of estimation instruction. This research required a year and the outcomes of the research can be listed as follows: 1. Social utilities of estimation were made clear, and a new trend of calculation teaching related to estimation instruction was shown. 2. The definition of estimation was given and actual examples of conducting an estimation among pupils in lower grades were given for them to have abundant experiences. 3. The ways of finding estimating values in fraction and decimal fraction were presented for the pupils to be able to conduct an estimation. 4. The following contents were given as a basic strategy for estimation. 1) Front-end strategy 2) Clustering strategy 3) Rounding strategy 4) Compatible numbers strategy 5) Special numbers strategy 5. In an instuction of estimation the meaning, method. and process of calculation and calculating algorithm were reviewed for the cultivation of children's creativity through promoting their basic skill, mathematical thinking and problem-solving ability. 6. The following contents were also covered as an estimation strategy for measurement 1) Calculating the sense of quantity on the size of unit. 2) Estimating the total quantity by frequent repetition of unit quantity. 3) Estimating the length and the volume by weighing. 4) Estimating unknown quantity based on the quatity already known. 5) Estimating the area by means of equivalent area transformation. 7. The ways of instructing mental computation were presented. 8. Reviews were made on the curricular and the textbook contents concerning estimation instructions both in Korea and Japan. and a new model of curriculum was devised with reference to estimation instruction data of the United States.

• 대한교통학회지
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• 제6권1호
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• pp.43-53
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• 1988

This study is to find the proper method of estimating urban road traffic capacity. To estimate road traffic capacity, the following methods are chosen ; 1) crossing point of Q-V and S-V, 2) critical velocity and density of Q-V-K model, 3) V-K model with density parameter. The density estimated through S-V relation is 174 veh./km. The methods used in this paper yields more stable values with 2286 veh./h/ in average. The estimated average capacity by three methods are 2272 veh./h. in multilane road. 2411 veh./h in three lane road and 2185 veh./h. in two lane road.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.101-110
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• 2004

The robots that will be needed in the near future are human-friendly robots that are able to coexist with humans and support humans effectively. To realize this, humans and robots need to be in close proximity to each other as much as possible. Moreover, it is necessary for their interactions to occur naturally. It is desirable for a robot to carry out human following, as one of the human-affinitive movements. The human-following robot requires several techniques: the recognition of the moving objects, the feature extraction and visual tracking, and the trajectory generation for following a human stably. In this research, a predictable intelligent space is used in order to achieve these goals. An intelligent space is a 3-D environment in which many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents providing humans with services. A mobile robot is controlled to follow a walking human using distributed intelligent sensors as stably and precisely as possible. The moving objects is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the intelligent space. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time trajectory to follow the walking human, the linear and angular velocities are estimated and utilized. The computer simulation and experimental results of estimating and following of the walking human with the mobile robot are presented.

• 한국IT서비스학회지
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• 제17권3호
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• pp.101-115
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• 2018

In order to promote the IT business efficiently, the Preliminary Feasibility Study has been conducted since 2004. It is to verify the feasibility of a large-scale IT project in advance and to determine whether to reflect the budget. It is more difficult to analyze the benefits of the IT project than other projects, because the IT project is carried out by combining tangible and intangible assets and human resources. For this reason, the Standard Guideline for Preliminary Feasibility Study in the IT field suggests a framework to support in estimating the benefits of the IT project. However, it includes the following problems : 1) level discrepancy among the benefit categories, 2) lack of types of benefit items, 3) no consideration of benefit inducing factors. So the framework is facing a low utilization. This study develops a new framework through a three-step research process. The new framework can be used not only for preliminary feasibility studies but also for estimating the benefits of general IT projects.

• Communications for Statistical Applications and Methods
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• 제28권5호
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• pp.411-424
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• 2021

Inference following two-stage adaptive designs (also known as two-stage randomization designs) with survival endpoints usually focuses on estimating and comparing survival distributions for the different treatment strategies. The aim is to identify the treatment strategy(ies) that leads to better survival of the patients. The objectives of this study were to assess the performance three commonly cited methods for estimating survival distributions in two-stage randomization designs. We review three non-parametric methods for estimating survival distributions in two-stage adaptive designs and compare their performance using simulation studies. The simulation studies show that the method based on the marginal mean model is badly affected by high censoring rates and response rate. The other two methods which are natural extensions of the Nelson-Aalen estimator and the Kaplan-Meier estimator have similar performance. These two methods yield survival estimates which have less bias and more precise than the marginal mean model even in cases of small sample sizes. The weighted versions of the Nelson-Aalen and the Kaplan-Meier estimators are less affected by high censoring rates and low response rates. The bias of the method based on the marginal mean model increases rapidly with increase in censoring rate compared to the other two methods. We apply the three methods to a leukemia clinical trial dataset and also compare the results.

• 제어로봇시스템학회논문지
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• 제15권2호
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• pp.148-154
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• 2009

In this paper, an embedded Kalman filter for a time-delayed controller is designed on an FPGA to estimate accelerations of the robot arm. When the time-delayed controller is used as a controller, the inertia estimation along with accelerations is needed to form the control law. Although the time-delayed controller is known to be robust to cancel out uncertainties in the nonlinear systems, performances are very much dependent upon estimating the acceleration term ${\ddot{q}}(t-{\lambda})$ along with inertia estimation ${\hat{D}}(t-{\lambda})$. Estimating accelerations using the finite difference method is quite simple, but the accuracy of estimation is poor specially when the robot moves slowly. To estimate accelerations more accurately, various filters such as the least square fit filter and the Kalman filter are introduced and implemented on an FPGA chip. Experimental studies of following the desired trajectory are conducted to show the performance of the controller. Performances of different filters are investigated experimentally and compared.

• 한국산업융합학회 논문집
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• 제24권4_2호
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• pp.453-465
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• 2021

Recently, photogrammetry, TLS(Terrestrial Laser Scanner), MMS(Mobile Mapping System)-based techniques have been applied to estimate earthwork volume for construction management. The primary objective of this study is to analyze the accuracy of earthwork volume estimating between photogrammetry and TLS, MMS that improves the traditional surveying method in convenience, estimating accuracy. For this, the following research works are conducted sequentially; 1) literature review, 2) core algorithm analysis, 3) surveying data acquisition using photogrammetry, TLS, MMS, 4) estimated earthwork volume comparison according to surveying method. As a result of the experiment, it was analyzed that there were earthwork volume errors of 1,207.5m³ (14.03%) of UAV-based digital map, 391.5m³(4.55%) of UAV, TLS integrated digital map, and 294.9m³(3.43%) of UAV, MMS integrated digital map. It is expected that the result of this study will be enormous due to the availability of the analyzed data.

• 치과방사선
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• 제18권1호
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• pp.13-25
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• 1988

Bone destruction was induced experimentally by the insertion of a bit of the arsenic compound into the pulp chambers of the right premolars and the artificial bone defects were produced in the periapical regions of the left premolars in 7 dogs. The serial standardized periapical radiographs using aluminum stepwedge attached to the XCP instruments, and resin bite blocks were taken following insertion of arsenic compound and at 2, 4, 7, 10, 14, 17, 21, 24 and 28 days in case of bone destruction and following bone injury and weekly thereafter for a total of 14 weeks in case of bone formation. The errors of the method were determined with error estimators described by the Duinkerke. All radiographs were evaluated by the visual examination after joint evaluation by three dental radiologists and analysed with densitometer. The following results were obtained; 1. Analysis of the bone destruction process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.04㎜, S.D. for the over-all error; 0.06㎜, S.D. for the positioning error; 0.05㎜) 2) The radiographic changes were observed after 7 days in 6 cases, 4 days in 1 case and 10 days in 1 case by the visual examination. 3) Aluminum equivalent values were diminished after 2 days and the diminution of 0.58±0.19㎜ was demanded to be detected by the visual examination. 2. Analysis of the bone formation process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.03㎜, S.D. for the over-all error; 0.04㎜ S.D. for the positioning error; 0.04㎜) 2) The radiographic changes were observed after 2 weeks in 5 cases and 3 weeks in 2 cases by the visual examination. 3) Aluminum equivalent values were increased after 1 week and the increase of 0.45±0.15㎜ was demanded to be detected by the visual examination. 4) Aluminum equivalent values were increased continuously for 7 or 9 weeks but there as only extremely small change after 10 weeks.

• Spatial Information Research
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• 제7권1호
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• pp.29-37
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• 1999

최근 주택을 선택함에 있어 주거환경에 대한 관심이 고조되고 있으며 이 가운데 강 또는 산 등 특정 대상으로의 조망과 개방감 여부가 주택가격을 결정짓는 중요한 요인으로 작용하고 있다. 실제로 기존 재고 주택시장의 아파트에 이러한 경관가치가 프리미엄의 형태로 주택가격에 내재되어 있는 것으로 나타났다. 따라서 신규 주택을 공급할 경우 특정 대상으로의 조망이나 개방감 여부를 판단할 수 있는 수단이 필요한 상황이다. 이에 본 연구에서는 3차원 시뮬레이션 프로그램(3D Studio Max)를 이용하여 개방감을 측정하는 방법을 모색하고자 하였다. 연구 결과 3차원 시뮬레이션 프로그램을 이용하여 개방감의 유무와 정도를 파악하는데 유용한 수단으로 이용될 수 있으며 이외의 다양한 목적으로도 활용될 수 있음을 제시하였다.

• 한국건설관리학회논문집
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• 제13권4호
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• pp.16-24
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• 2012

본 연구는 국내 외 건설사업관리 유사 건설기술용역 대가 기준 및 사례분석을 토대로 합리적인 건설사업관리 대가기준을 제안하는 것을 목적으로 한다. 이를 위해 기존의 건설사업관리 대가의 적정성을 분석하고, 사례분석을 통한 인력투입 실태를 조사하였으며, 비상주 인력의 적정수준에 대해 고찰하였다. 사례분석결과, 현행 건설사업관리 대가산정 체계는 책임감리와의 대가산정 방식의 이원화, 비 현실적인 대가기준 및 인력배치 등이 문제점으로 도출되었다. 이를 위한 개선 방안으로 건설용역 대가산정 방식의 정비, 건설사업관리 대가수준의 현실화, 사업초기단계 배치인력의 탄력성 확보, 사업특성을 고려한 비상주 인력 활용을 제안하였다. 본 연구는 향후 건설사업관리의 대가수준의 현실화 및 대가산정을 위한 접근방법의 개선에 기여하여 건설사업관리 업무의 효율성 향상에 도움이 될 것으로 기대된다.