• 한국건설관리학회논문집
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• 제16권1호
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• pp.101-109
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• 2015

투자에 의해 기대되는 경제적 효과는 실질할인율의 자승으로 매년 나누어서 현재가치로 전환된다. 따라서 실질할인율이 경제성 분석결과에 미치는 영향은 다른 요인들보다 크다. 실질할인율을 예측하는 기존의 일반적인 방법은 과거 특정기간의 평균값을 적용하는 것이다. 본 연구에서는 실질할인율의 예측 정확도를 향상시키기 위한 방법을 제안하였다. 먼저 실질할인율을 구성하는 기업대출 이자율과 소비자 물가지수에 영향을 미치는 경제변수들을 도출하였다. 기업대출 이자율에 영향을 주는 변수들로는 콜 금리와 환율, 소비자 물가지수에 영향을 주는 경제변수는 생산자 물가지수를 선정하였다. 다음으로 실질할인율과 선정된 변수들과의 영향관계를 검정하였다. 영향관계가 존재하는 것으로 분석되었다. 마지막으로 관련된 경제 변수들을 기반으로 2008년부터 2010년까지의 실질할인율을 예측하였다. 예측 결과의 정확도는 실측값과 평균값의 결과와 비교되었다. 실측값이 적용된 실질할인율은 -1.58%였으며, 예측 값은 -0.22%, 평균값은 6.06%으로 분석되었다. 본 연구에서 제안한 방법은 금융위기와 같은 특수 상황을 고려하지 않은 것이지만, 평균값보다 예측 정확도가 크게 우수한 것으로 분석되었다.

• Journal of Multimedia Information System
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• 제8권1호
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• pp.1-10
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• 2021

Heart Rate is a crucial physiological parameter that provides basic information about the state of the human body in the cardiovascular system, as well as in medical diagnostics and fitness assessments. At present day, it has been demonstrated that facial video-based photoplethysmographic signal captured using a low-cost RGB camera is possible to retrieve remote heart rate. Traditional heart rate measurement is mostly obtained by direct contact with the human body, therefore, it can result inconvenient for long-term measurement due to the discomfort that it causes to the subject. In this paper, we propose a non-contact-based remote heart rate measuring approach of the subject which depends on the color intensity variation of the subject's facial skin. The proposed method is applied in two regions of the subject's face, forehead and cheeks. For this, three different algorithms are used to measure the heart rate. i.e., Fast Fourier Transform (FFT), Independent Component Analysis (ICA) and Principal Component Analysis (PCA). The average accuracy for the three algorithms utilizing the proposed method was 89.25% in both regions. It is also noteworthy that the FastICA algorithm showed a higher average accuracy of more than 92% in both regions. The proposed method obtained 1.94% higher average accuracy than the traditional method based on average color value.

• Journal of Positioning, Navigation, and Timing
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• 제12권3호
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• pp.237-244
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• 2023

A signal generation simulator is an economical and useful solution in Global Navigation Satellite System (GNSS) receiver design and testing. A software-defined radio approach is widely used both in receivers and simulators, and its flexible structure to adopt to new signals is ideally suited to the testing of a receiver and signal processing algorithm in the signal design phase of a new satellite-based navigation system before the deployment of satellites in space. The generation of highly accurate delayed sampled codes is essential for generating signals in the simulator, where its sampling rate should be chosen to satisfy constraints such as Nyquist criteria and integer and non-commensurate properties in order not to cause any distortion of original signals. A high sampling rate increases the accuracy of code delay, but decreases the computational efficiency as well, and vice versa. Therefore, the selected sampling rate should be as low as possible while maintaining a certain level of code delay accuracy. This paper presents the lower limits of the sampling rate for GNSS signal generation simulators. In the simulation, two distinct code generation methods depending on the sampling position are evaluated in terms of accuracy versus computational efficiency to show the lower limit of the sampling rate for several GNSS signals.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.692-698
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• 2022

With the expansion of domestic hydrogen fuelling station infrastructure, it is necessary to secure reliability among hydrogen traders, and for this, technology to accurately measure hydrogen is important. In this study, 4 types of hydrogen trading volume calculation models (model 1-4) were presented to improve the accuracy of the hydrogen trading volume. In order to obtain the reference value of model 4, and experiment was conducted using a flow rate measurement equipment, and the error rate of the calculated value for each model was compared and analyzed. As a result, model 1 had the lowest metering accuracy, model 2 had the second highest metering accuracy and model 3 had the highest metering accuracy until a certain point. But after the point, model 2 had the highest metering accuracy and model 3 had the second metering accuracy.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.558-565
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• 2015

The current methods, such as Binomial Probability Distribution or T-test, to calculate the number of samples of Precise Guided Missiles(PGMs) for test and evaluation are statistically problematic to make reasonable decisions thus use the budget efficiently. Also, the method to verify an accuracy rate of the PGMs using these old methods seems to be lack of objectiveness. This paper presents an effective, efficient solution adapted from the clinical medicine testing method of healthcare industry research, which may overcome our problems. This method considers and addresses both manufacturers' and consumers' risk simultaneously. By taking into account the weapon system project characteristics which take a relatively longer time and require higher-level budget, this approach also suggests a reasonable and feasible method to determine the amount of samples of the PGMs and making a criterion to verify an accuracy rate of the missiles that are required to test. Thus, this method is expected to contribute to acquisition and operations of high-reliability PGMs by MND and its field-users.

• 사상체질의학회지
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• 제19권1호
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• pp.78-89
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• 2007

1. Objectives This is the comparative study with hand-operated measurement method & Automatic measurement method, in order to convert the automatic measurement method. 2. Methods We measured the body of patients(hand-operated width 5 places and hand-operated circumference 8 places, Automatic width 5 places) and analyzed the anthropometric data dividing into sex, age, BMI. 1057 patients's data are used in the analysis. 3. Results and Conclusions 1) 5th Width variable which was measured during lying down was not a sasang constitutional difference. 2) Diagnostic accuracy rate of the body measurement by Width which was measured during lying down and Width which IBS standing was 40-60%. 3) Diagnostic accuracy rate of Automatic & hand-operated measuring was not a big difference.

• 한국멀티미디어학회논문지
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• 제21권7호
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• pp.779-786
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• 2018

In this paper, we are applied a nerve network to allow for the reflection of data learning methods in their overall forms by using cluster data rather than data learning by the stages and then selected a nerve network model and analyzed its variables through learning by the cluster. The CkLR algorithm was proposed to analyze the reaction variables of clustering outcomes through an approach to the initialization of K-means clustering and build a model to assess the prediction rate of clustering and the accuracy rate of prediction in case of new data inputs. The performance evaluation results show that the accuracy rate of test data by the class was over 92%, which was the mean accuracy rate of the entire test data, thus confirming the advantages of a specialized structure found in the proposed learning nerve network by the class.

• 센서학회지
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• 제17권6호
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• pp.447-453
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• 2008

Respiration rate is one of the important vital signs. Photo-plethysmography (PPG) measurement especially on a finger has been widely used in pulse oximetry and also used in estimating respiration rate. It is well known that PPG contains respiration-induced intensity variation (RIIV) signal. However, the accuracy of finger PPG method has been controversial. We introduced a new technique of enhancing motion artifact by respiration. This was achieved simply by measuring PPG on the thorax. We examined the accuracy of these two PPG methods by comparing with two existing methods based on thoracic volume and nostril temperature changes. PPG sensing on finger tip, which is the most common site of measurement, produced 6.1 % error. On the other hand, our method of PPG sensing on the thorax achieved 0.4 % error which was a significant improvement. Finger PPG is sensitive to motion artifact and it is difficult to recover fully small respiratory signal buried in waveform dominated by absorption due to blood volume changes. Thorax PPG is poor to represent blood volumes changes since it contains substantial motion artifact due to respiration. Ironically, this inferior quality ensures higher accuracy in terms of respiration measurement. Extreme low-cost and small-sized LED/silicon detector and non-constrained reflection measurement provide a great candidate for respiration estimation in ubiquitous or personal health monitoring.

• 음성과학
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• 제12권3호
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• pp.139-151
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• 2005

Previous studies have shown that Korean students have difficulty identifying some English consonants which are not in the Korean sound inventory. The aim of this study was to examine the accuracy rate of English consonants correctly identified by 130 college students in order to find out which English consonants were difficult for the students to perceive. The subject's task was to identify one of the minimal pairs played in a quiet laboratory classroom. 100 minimal pairs consisted of syllables with various onsets or codas: stops, fricatives, affricates, liquids and nasals. Results were as follows: First, the average score of the English major group was significantly higher than that of the non-English major group. Second, there was a similar distribution in the rank order of minimal pairs sorted by the accuracy rate between the two groups. Third, the accuracy rate systematically decreased as each score range decreased. Fourth, the students showed higher accuracy in the perception of liquids than that of the stop-fricative contrast. Fifth, the accuracy score in onset position was higher than in coda position. Finally, the students still had problem telling voiced consonants from voiceless ones, especially in coda position. It would be desirable to extend the present research to middle or high school students to fundamentally resolve those listening problems.