• 플랜트 저널
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• 제8권1호
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• pp.50-59
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• 2012

The current dual-watchdog estimation system has individually calculated the construction, the engineering and the procurement cost. The dual-watchdog estimation system is inefficient and prolonged estimation period because of the lack of the interoperability and the difference of material unit cost and construction unit cost. In order to resolve this problem, new estimation software was developed. The estimation software is developed by making up for the weak points in existing estimation method. The cost data with the same standard is the key point. And this software enhanced accuracy and speed of the data search in stylized estimation standard. A summary of the construction, the engineering and the procurement cost was generated in this estimation software. The unit rate about the labor cost, equipment and expense through a sheet was handled. The developed estimation software has five categories on engineering cost, procurement cost, construction cost and subcontractor management sheet. In this study, the estimation software to supplement the faults of the existing estimation method was developed. And estimation software on petrochemical projects increases an efficiency of the estimation work.

• 한국초등수학교육학회지
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• 제19권3호
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• pp.267-287
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• 2015

본 논문에서는 2009 개정 초등학교 수학과 교육과정에 따른 교과서에서 취급하는 어림재기 유형 및 전략을 분석하고, 그 결과를 바탕으로, 차후의 교육과정 및 교과서 개발을 위한 시사점으로 다음 네 가지를 제시한다. 첫째, 교육과정과 교과서에서 어림재기 관련 내용을 일치시키는 것이 필요하다. 2009 개정 교육과정에서는 길이, 들이, 무게, 각도의 어림재기만을 제시하고 있다. 그러나 교과서에서는 시간과 넓이의 어림재기도 취급하고 있다. 둘째, 교과서에서 어림재기 전략을 다양하게 안내할 필요가 있다. 지도서에서는 어림재기 전략으로 참조대상 사용하기 전략, 덩어리로 나누기 전략, 단위로 나누기 전략의 세 가지를 예시하고 있지만, 교과서에서는 그렇지 않다. 셋째, '어림하다'의 의미를 명확히 할 필요가 있다. 교과서에서 '어림하다'가 어림재기의 맥락으로만 사용되는 것이 아니다. 넷째, 교육과정에서 시간, 넓이, 부피의 어림재기의 취급 여부를 명확히 할 필요가 있다.

• 한국IT서비스학회지
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• 제11권1호
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• pp.197-210
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• 2012

This paper presents the ways that can improve the Software Cost Estimation Guidelines in order to replace those that are expected to be abolished at February, 2012, and solve the problems that are being occurred in the current Software Cost Estimation Guidelines. By using multidimensional modeling of OLAP(On-Line Analytical Processing), this paper does three dimensional modeling that considers the product/service view, process view and skill view. Also, it presents the identification method of cost estimation data through the view of each dimension. Furthermore, it defines the software cost estimation process and adapts them into the bottom up estimation and the top down estimation. Finally, it proposes the access of cost estimation data by the multidimensional analysis of OLAP.

• 한국정보기술학회 영문논문지
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• 제6권1호
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• pp.45-57
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• 2016

This paper proposes an adaptive channel estimation scheme for OFDM-based IEEE 802.11ad wireless local area network (WLAN). The standard supports two types of information of OFDM packets for estimating the communication channels, which are the channel estimation field (CEF) of preamble and pilot subcarriers. The CEF-based channel estimation provides better BER (bit error rate) performance at slow fading channel state, whereas the pilot-based channel estimation is good at fast fading channel state. Hence, a combined channel estimation method is introduced to improve the performance. The prediction of the channel state to select the proper channel estimation method is required. In this work, an adaptive channel estimation scheme is also proposed to improve the performance of channel estimation (CE). Basing on a channel quality indicator (CQI), the proper channel estimation method corresponding to the channel type is decided.

• Journal of Oral Medicine and Pain
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• 제43권4호
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• pp.118-124
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• 2018

Purpose: Age estimation is often used in the identification of living persons. Various methods are used for age estimation using teeth, and there are many studies on the methodology. But the study of changes in the social aspects of age estimation with the passage of times is still insufficient. Therefore, the purpose of this study is to analyze the age estimation cases in the social aspects and to investigate the changes of age estimation cases in Jeollabuk-do. Methods: From January 2008 to December 2015, 76 cases of age estimation were collected. The collected data were organized and analyzed. The distribution of patients by age and year, the difference between alleged and registered age, the purpose of age estimation, and regional distribution were examined. In addition, we compared the previous study which analyzed the age estimation cases in Jeollabuk-do from 2000 to 2007. Results: According to the distribution by age, the age distribution was the largest in the 50s and 60s, with 69.8%. The most reason to correct age was related to welfare benefits (38.2%), and most of the people who corrected for welfare benefits were over 50 years old. The age correction for purpose of welfare benefits existed every year during the study period. As the result of comparison with previous study, total number of age estimation cases was decreased very sharply, and distribution by age group was also changed. Conclusions: Changes in age estimation cases were observed when compared to the previous study. A significant decrease in the total number of age estimation cases was observed, but the number of age estimation in the 50s did not decrease. Although the total number of age estimation requests decreases, age estimation in the elderly are likely to persist. Thus, it is necessary to study new age estimation methods suitable for the elderly.

• Journal of the Korean Statistical Society
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• 제27권4호
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• pp.507-514
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• 1998

The minimum distance estimation based on the L$_2$ distance between a model density and a density estimator is studied from M-estimation point of view. We will show that how a model density and a density estimator are incorporated in order to create an M-estimation function. This method enables us to create an M-estimating function reflecting the natures of both an assumed model density and a given set of data. Some new types of M-estimation functions for estimating a location and scale parameters are introduced.

• 한국컴퓨터정보학회논문지
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• 제23권8호
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• pp.51-57
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• 2018

In this paper, we investigate the impact of channel estimation error on the D2D power control algorithm. In the previous work, D2D power control algorithm has been proposed under the assumption that the channel between the transmitter and the corresponding receiver is perfectly estimated. In reality, the channel estimation error is more often the case. The first question is that the power control algorithm designed for perfect channel estimation is still valid under the channel estimation error environment ? The second question is, if it is not valid, what could be the possible remedy for the channel estimation error ? In this paper, to answer the first question, we investigate the impact of the channel estimation error on the power control algorithm. We first review the D2D power control algorithm designed for perfect channel estimation. Then, we model the channel estimation error. Finally, we summarize the main results observed from the analysis of the simulation.

• 전자공학회논문지S
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• 제35S권2호
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• pp.146-156
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• 1998

Thispapr proposes hybrid navigation parameter estimation using sequential aerial images. The proposed navigation parameter estimation system is composed of two parts: relative position estimation and absolute position estimation. the relative position estimation recursively computes the current velocity and absolute position estimation. The relative position estimation recursively computes the current velocity and position of an aircraft by accumulating navigation parameters extracted from two succesive aerial images. Simple accumulation of parameter values decreases reliability of the extracted parameters as an aircraft goes on navigating. therefore absolute position estimation is required to compensate for position error generated in the relative position step. The absolute position estimation algorithm combining image matching and digital elevation model(DEM) matching is presented. Computer simulation with real aerial image sequences shows the efficiency of the proposed hybrial algorithm.

• Communications for Statistical Applications and Methods
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• 제27권1호
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• pp.97-108
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• 2020

This paper compares several methods for estimating parameters of normal inverse Gaussian distribution. Ordinary maximum likelihood estimation and the method of moment estimation often do not work properly due to restrictions on parameters. We examine the performance of adjusted estimation methods along with the ordinary maximum likelihood estimation and the method of moment estimation by simulation and real data application. We also see the effect of the initial value in estimation methods. The simulation results show that the ordinary maximum likelihood estimator is significantly affected by the initial value; in addition, the adjusted estimators have smaller root mean square error than ordinary estimators as well as less impact on the initial value. With real datasets, we obtain similar results to what we see in simulation studies. Based on the results of simulation and real data application, we suggest using adjusted maximum likelihood estimates with adjusted method of moment estimates as initial values to estimate the parameters of normal inverse Gaussian distribution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1768-1769
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• 2011

The nonlinear estimation and the pseudo-linear estimation are used to treat the target localization in sensor network which provides range difference of arrival (RDOA) measurements. It is known that the nonlinear estimation has sensitive problem for the initial estimate and the pseudo-linear estimation has a large estimation error. The QCLS method is the typical estimator of the methods for pseudo-linear estimation. However the estimate by using the QCLS method includes the estimation error because the first stage of two estimation processes of the QCLS method causes the biased estimation error. Therefore we propose a instrumental variables(IV) method for minimizing the estimation error of the first stage. The simulation shows that the performance of the proposed method is superior to the QCLS method.