• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.612-613
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• 2015

As a construction project is recently becoming large-scaled and complex, construction process plan and management for successful performance of a construction project has become more important. Especially a reasonable estimation plan of activity duration is required because the activity duration is directly related to the determination of the entire project duration and budget. However, the activity duration is used to estimate by the experience of a construction manager and past construction records. Furthermore, the prediction of activity duration is more difficult because there is some uncertainty caused by various influencing factors in a construction project. This study suggests an estimation model of construction activity duration using neural network theory for a more systematic and objective estimation of each activity duration. Because suggested model estimates the activity duration by a reasonable schedule plan, it is expected to reduce the error between planning duration and actual duration in a construction project. And it can be a more systematic estimation method of activity duration comparing to the estimation method by experience of project manager.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.74-80
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• 2001

The estimation of recurrence interval for fault activity and earthquake is an important input parameter for seismic hazard assessment. In this study, the methods of recurrences interval estimation were reviewed and tentative calculation was performed for age dating data which have uncertainty. Age dating data come from previous studies of Ulsan fault system which is a well developed lineament in the southeastern part of korean Peninsula. Age dating for fault gouges, parent rocks, Quaternary sediments and veins were carried out by several researchers through various methods. Recurrence interval for fault activity was estimated on the basis of the age dating data of minor fault gouge and sediments during past 3Ma. The estimated recurrence interval was about 430-500 ka. Exact estimation of recurrence interval for fault activity need to compile more geological data and fault characteristics such as fault length, amount of displacement, slip rate and accurate fault movement age. In the future, the methods and results of fault recurrence interval estimation should be considered for establishing the criteria for domestic active fault definition.

• 대한의생명과학회지
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• 제12권4호
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• pp.439-442
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• 2006

To evaluate the postmortem changes in activities of oxygen free radical metabolizing enzymes, the rats were sacrificed with cervical dislocation and were kept in an incubator at $25^{\circ}C$, 70% of humidity for 12 hours. The activities of aniline hydroxylase, catalase, glutathione-S-transferase and superoxlde dismutase were decreased with the time. On the other hand, the activity and type conversion ratio (type D ${\to}$type O) of hepatic xanthine oxidase (XO) were gradually increased. From these changes of XO, the estimation of death time (mathematical equation) could be determined with the least square method. To clarify the cause of increasing XO activity, enzyme kinetics were examined. The Km values of XO were decreased with the time. In conclusion, the determination of liver XO activity might be used for the estimation of death time in the early postmortem period.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권2호
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• pp.76-84
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• 2002

On-line conversion estimation of enzymatic esterification reactions in solvent-free media was investigated. In principle, conversion to ester can be determined from the amount of water produced by the reaction, because water is formed as a by-product in a stoichiometric manner. In this study, we estimated the water production rate only from some measurements of relative humidity and water balances without using any analytical methods. In order to test the performance of the on-line conversion estimation, the lipase-catalyzed esterification of n-capric acid and n-decal alcohol in solvent-free media was performed whilst controlling water activity at various values. The reaction conversions estimated on-line were similar to those determined by offline gas chromatographic analysis. However, when the water activity was controlled at higher values, discrepancies between the estimated conversion values and the measured values became significant. The deviation was found to be due to the inaccurate measurement of the water content in the reaction medium during the initial stages of the reaction. Using a digital filter, we were able to improve the accuracy of the on-line conversion estimation method considerably. Despite the simplicity of this method, the on-line estimated conversions were in good agreement with the off-line measured values.

• International Journal of Internet, Broadcasting and Communication
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• 제11권4호
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• pp.26-30
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• 2019

This paper proposes a new voice activity detection (VAD) method which is based on SNR and non-intrusive speech intelligibility estimation. In the conventional SNR-based VAD methods, voice activity probability is obtained by estimating frame-wise SNR at each spectral component. However these methods lack performance in various noisy environments. We devise a hybrid VAD method that uses non-intrusive speech intelligibility estimation as well as SNR estimation, where the speech intelligibility score is estimated based on deep neural network. In order to train model parameters of deep neural network, we use MFCC vector and the intrusive speech intelligibility score, STOI (Short-Time Objective Intelligent Measure), as input and output, respectively. We developed speech presence measure to classify each noisy frame as voice or non-voice by calculating the weighted average of the estimated STOI value and the conventional SNR-based VAD value at each frame. Experimental results show that the proposed method has better performance than the conventional VAD method in various noisy environments, especially when the SNR is very low.

• 산업경영시스템학회지
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• 제6권9호
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• pp.1-5
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• 1983

본 연구는 가동샘플링(Activity Sampling)에 대한 실태조사샘플링이론의 적용과 표준시간추정에 대한 가동샘플링의 적용에 대한 것으로, 집단·층별과 다단샘플링법을 무작위샘플링과 체계적 샘플링과 관련하여 연구했다. 정보를 최대화하기 위한 추정방법은 연구에 소요되는 비용에 따라 정해지며, 추정치의 정도를 추정하기 위한 절차의 규정도 고려했다. 전형적 작업로트의 생산자료로부터 표준요소작업수행시간을 추정하기 위해 다중회귀와 선형계획의 적용도 연구했다.

• 대한전자공학회논문지SP
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• 제46권5호
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• pp.101-110
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• 2009

사용자의 활동 신호 또는 생체 신호를 무의식적이고 무구속적으로 측정하는 방법은 유비쿼터스 환경에서 헬스케어 뿐만 아니라 관련된 사용자 인터페이스를 실현하기 위해서 중요하다. 특히 무구속적인 측정은 장시간 동안 사용자의 활동을 모니터링하기 위한 활동 상태 추정 시스템에 사용되어야 한다. 본 논문에서는 가속도센서를 탑재한 핸드헬드 단말기의 시계열 가속도 분석을 통한 사용자 활동 상태 추정 기법을 제안한다. 제안된 사용자 활동 추정 시스템은 사용자의 불편함을 최소화하기 위해서 가속도센서를 사용자가 일상 생활동안 항상 휴대하고 있는 핸드헬드 단말기에 부착되어 구성되고, 이것을 실생활에서 실용적으론 구현하기 위해서 핸드헬드 단말기가 사용자에 의해서 휴대될 수 있는 위치를 앞주머니, 뒷주머니, 윗주머니, 가방, 허리, 손으로 쥐기 등과 같이 고려하였다.

• 대한산업공학회지
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• 제15권2호
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• pp.103-108
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• 1989

PERT formulae for the mean and variance of activity time are near exact only over a short interval of the concentration parameter which is defined as the sum of the two shape parameters of the beta distribution. Aiming a better estimation of the mean and variance of activity time, we propose a method of subjectively estimating this concentration parameter via estimating the probability of completing the activity within a specified time interval.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1456-1461
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• 2004

Companies of Build-to-Order(BTO) strive to achieve customer responsiveness and cost efficiency simultaneously. The success of BTO depends upon the high volume production based on product plat form and delayed differentiation principle on the one hand, and upon the rapid estimation of delivery and cost for the customer orders on the other hand. Expeditious processing of a specific order requires the rearrangement of production resources and the schedule, which results in increased cost. This paper describes a cost estimation method using activity-based costing depending on the schedule change caused by urgent customer orders.

• 한국산업정보학회논문지
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• 제16권4호
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• pp.9-18
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• 2011

본 논문에서는 모델 기반으로 추정한 사람의 시선 방향을 이용하여 실내 환경에서 발생 할 수 있는 사람의 행동을 인식하는 방법을 제안한다. 제안하는 방법은 크게 두 단계로 구성된다. 첫째, 행동 인식을 위한 사전 정보를 얻는 단계로 사람의 머리 영역을 검출하고 시선 방향을 추정한다. 사람의 머리 영역은 색상 정보와 모양 정보를 이용하여 검출하고, 시선 방향은 머리와 얼굴의 관계를 표현한 베이지안 네트워크 모델을 이용하여 추정한다. 둘째, 이벤트와 사람의 행동을 나타내는 시나리오를 인식하는 단계이다. 이벤트는 사람의 상태 변화로 인식하고, 시나리오는 이벤트들의 조합과 제약 사항을 이용하여 규칙 기반으로 인식한다. 본 논문에서는 시선방향과 연관이 있는 4 가지의 시나리오를 정의하여 실험 한다. 실험을 통해 시선 방향 추정의 성능과 시선 방향이 고려된 상황에서의 행동 인식 성능을 보인다.