• 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.

• 한국건설관리학회논문집
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• 제5권6호
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• pp.138-145
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• 2004

공사에 소요되는 기간은 시설물의 품질과 비용에 직접적인 영향을 미치지만, 고등학교 시설공사의 경우 경험과 직관에 의거하여 공기를 산정하고 있어 공사수행과정에서 계약당사자 간에 분쟁이 많이 발생하고 있다. 본 논문은 고등학교 시설공사에 소요되는 기간의 산정에 영향을 미치는 다양한 요인을 분석하여 공기 산정기준을 제안하는 것으로, 인천지 역에서 최근에 개교한 고등학교의 실적자료를 수집하여 다중선형 회귀분석 하였다. 회귀분석 결과로 얻은 순 공사기간에 인천지 역의 기후특성을 고려하여 산정한 작업불가능기간을 더하여 총 공사기간을 산출 하였다. 본 논문에서 제안한 공기 산정식은 공사발주 및 계약 시 계약공기를 정확하게 산정 하는데 도움을 줄 수 있을 것이다

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.809-815
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• 1998

This study has been performed to investigate MRR(metal removal rate) surface roughness with various pulse-on duration using the copper and graphite electrode according to the electrode size on the heat treated STD 11 which is extensively used for metallic molding steel in the EDM. The results obtained are as follow ;a)MRR increases a lot when pulse-on duration is 100 $\mu{s}$ or less but MRR has little difference with pulse-on duration of 100 $\mu{s}$ or more b) According to the increase of Pulse-on duration the large the electrode size the more MRR c) Safe discharge is needed to make maximum of MRR and the metallic organization must be complicated for discharge induction. d) Actual machining time is longer than theoretical machining time at the short pulse-on duration because of skin effect of current. e) Graphite electrode needs the larger electric discharge energy than copper electrode to remove remained chips completely.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.608-615
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• 2022

Construction projects are large-scale projects that require extensive construction costs and resources. Especially, scheduling is considered as one of the essential issues for project success. However, the schedule and resource management are challenging to conduct in high-tech construction projects including complex design of MEP and architectural finishing which has to be constructed within a limited workspace and duration. In order to deal with such a problem, this study suggests resource and sequence optimization using constraint programming in construction projects. The optimization model consists of two modules. The first module is the data structure of the schedule model, which consists of parameters for optimization such as labor, task, workspace, and the work interference rate. The second module is the optimization module, which is for optimizing resources and sequences based on Constraint Programming (CP) methodology. For model validation, actual data of plumbing works were collected from a construction project using a five-minute rate (FMR) method. By comparing actual data and optimized results, this study shows the possibility of reducing the duration of plumbing works in construction projects. This study shows decreased overall project duration by eliminating work interference by optimizing resources and sequences within limited workspaces.

• 한국작물학회지
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• 제30권2호
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• pp.131-139
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• 1985

이모작재배에 적합한 극조숙 양질 다수성 소맥품종육성을 위하여 등수기간에 관여하는 유전자 작용에 대한 연구는 매우 중요하다. 추파성품종 Yam-hill과 Hyslop, 춘파성품종 Red Bobs와 Siete Cellos를 사용하여 4 $\times$ 4 complete diallel crosses F$_1$, F$_2$, BC$_1$ 및 BC$_2$를 작성, Jinks-Hay-man model를 이용하여 등숙기간에 관여하는 유전자 작용을 분석하였다. 본 시험은 오레곤 주립대학교에서 실시되었다. 그 결과의 개요는 다음과 같다. 전등숙기간인 출수에서 생리적 성숙기까지의 기간과 출수에서 개화까지의 기간에서 maternal effect 가 인정되지 않았으며 비대립유전자간 상호작용도 발현되지 않았다. 개화에서 생리적 성숙기까지의 기간에서는 비대립유전자간에 상호작용이 인정되었다. 춘파성 품종인 Red Bobs와 Siete Cellos는 전등숙기간과 출수에서 개화까지의 기간을 지배하는 우성유전자들을 가지고 있었으며 짧은 쪽에 비하여 긴쪽이 우성으로 발현되고 있었다. 대조적으로 추파성 품종인 Yamhill 과 Hyslop은 개화에서 생리적 성숙기까지의 기간을 지배하는 우성유전자들을 가지고 있었으며 긴쪽이 우성으로 작용하고 있었다. 그리고 이 유전자들은 문배친들간에 독립적으로 분포되어 있었다.

• 음성과학
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• 제10권4호
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• pp.7-21
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• 2003

Sums-of-Products models were built for segment duration prediction of spoken Korean. An experiment for the modelling was carried out to apply the results to Korean text-to-speech synthesis systems. 670 read sentences were analyzed. trained and tested for the construction of the duration models. Traditional sequential rule systems were extended to simple additive, multiplicative and additive-multiplicative models based on Sums-of-Products modelling. The parameters used in the modelling include the properties of the target segment and its neighbors and the target segment's position in the prosodic structure. Two optimisation strategies were used: the downhill simplex method and the simulated annealing method. The performance of the models was measured by the correlation coefficient and the root mean squared prediction error (RMSE) between actual and predicted duration in the test data. The best performance was obtained when the data was trained and tested by ' additive-multiplicative models. ' The correlation for the vowel duration prediction was 0.69 and the RMSE. 31.80 ms. while the correlation for the consonant duration prediction was 0.54 and the RMSE. 29.02 ms. The results were not good enough to be applied to the real-time text-to-speech systems. Further investigation of feature interactions is required for the better performance of the Sums-of-Products models.

• Asia pacific journal of information systems
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• 제34권1호
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• pp.226-247
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• 2024

Most studies on recommender systems to evaluate recommendation performances focus on offline evaluation methods utilizing past customer transaction records. However, evaluating recommendation performance through real-world stimulation becomes challenging. Moreover, such methods cannot evaluate the duration of the recommendation effect. This study measures the personalized recommendation (stimulus) effect when the product recommendation to customers leads to actual purchases and evaluates the duration of the stimulus personalized recommendation effect leading to purchases. The results revealed a 4.58% improvement in recommendation performance in the online environment compared with that in the offline environment. Furthermore, there is little difference in recommendation performance in offline experiments by period, whereas the recommendation performance declines with time in online experiments.