• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.793-795
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• 2005

지식 시스템(knowledge system)을 구축한다는 것은 구조적인 지식(structured knowledge)과 추론 모델(reasoning model)을 개발하기 위한 활동을 모델링하는 것을 말한다. 특별히 모델을 재사용한다는 것은 새로운 응용(application)을 만드는 데 있어서 비용과 시간을 감소시켜 준다. 서로 다른 응용과 영역(domain)에서 지식 구성요소를 재사용 한다는 것은 전문가 지식의 습득과 추론 과정을 정확하게 기술하는데 도움을 주게 된다. 본 연구에서는 문제해결방법 재사용에 대한 기존의 몇 가지 방법들을 함께 사용함에 의해서 급성복통과 관련된 질환 진단 태스크를 모델링할 수 있는 진단시스템을 제안하여 기존 시스템과 비교했을 때 지식 획득율을 향상시키게 되었다.

• Annual Conference of KIPS
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• 2009.04a
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• pp.1159-1162
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• 2009

브로드캐스팅 프로토콜은 무선 애드 혹 네트워크에서 컨트롤 메시지를 전체 노드에 전송하기 위한 목적으로 널리 사용된다. 전통적인 브로드캐스팅 프로토콜은 모든 노드가 처음 받은 메시지를 재전송 하기 때문에 극심한 중복전송과 충돌문제가 발생한다. 이러한 문제를 해결하기 위해 최근에 효율적으로 재전송노드를 줄이기 위한 브로드캐스팅 기법들이 제안되었지만 여전히 다수의 불필요한 재전송이 발생한다. 제안 기법은 1-홉 이웃노드의 위치정보를 이용하여 전파반경에 내접하는 정삼각형의 꼭짓점을 구하고 각 꼭짓점에 가장 가까운 이웃노드를 재전송노드로 선택한다. 우리는 먼저 재전송 노드를 최소화하기 위한 이상적인 모델을 제시하고 이상적인 모델에 근접하기 위한 방법을 설명한다. 시뮬레이션 결과를 통해 제안 기법이 기존의 효율적인 브로드캐스팅 프로토콜보다 성능이 우수하며 재전송 노드수가 lower bound에 근접하는 것을 보여준다.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.29-40
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• 2024

This study aimed to evaluate the swelling behavior characteristics of KJ-II buffer blocks by performing numerical analysis of swelling pressure measurement experiments using the nonlinear elasticity model of COMSOL Multiphysics. The analysis was conducted under boundary conditions that included isotropic constraints and water injection pressure, mirroring the experimental settings. Validation of the numerical model was achieved by comparing its outputs with experimental results. The validated model was then used to simulate swelling deformations under unconfined conditions and to analyze swelling pressure as influenced by dry density and the geometric shape of the buffer material. The results accurately represented the swelling deformation observed during the saturation process and demonstrated that swelling pressure increases with higher dry density. Moreover, simulations concerning the geometric shape of the buffer material indicated a markedly faster rate of pressure increase in U-shaped samples compared to cylindrical ones. Analysis suggested that stress manifested preemptively near the internal edges of U-shaped samples during saturation. To enhance the simulation's fidelity to actual buffer material behavior, further refinement of the analysis model using a nonlinear elasticity model is recommended.

• Atmosphere
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• v.32 no.4
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• pp.263-276
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• 2022

The observation error of satellite radiation data that assimilated into the Korean Integrated Model (KIM) was diagnosed by applying the Hollingsworth and Lönnberg and Desrozier techniques commonly used. The magnitude and correlation of the observation error, and the degree of contribution for the satellite radiance data were calculated. The observation errors of the similar device, such as Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit-A shows different characteristics. The model resolution accounts for only 1% of the observation error, and seasonal variation is not significant factor, either. The observation error used in the KIM is amplified by 3-8 times compared to the diagnosed value or standard deviation of first-guess departures. The new inflation value was calculated based on the correlation between channels and the ratio of background error and observation error. As a result of performing the model sensitivity evaluation by applying the newly inflated observation error of ATMS, the error of temperature and water vapor analysis field were decreased. And temperature and water vapor forecast field have been significantly improved, so the accuracy of precipitation prediction has also been increased by 1.7% on average in Asia especially.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.184-187
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• 2020

다중 지문 기계독해는 질문과 여러 개의 지문을 입력받고 입력된 지문들에서 추출된 정답 중에 하나의 정답을 출력하는 문제이다. 다중 지문 기계독해에서는 정답이 있을 단락을 선택하는 순위화 방법에 따라서 성능이 크게 달라질 수 있다. 본 논문에서는 단락 안에 정답이 있을 확률을 예측하는 단락 재순위화 모델과 선택된 단락에서 서술형 정답을 위한 세부적인 정답의 경계를 예측하는 세부 단락 선별 기법을 제안한다. 단락 순위화 모델 학습의 경우 모델 학습을 위해 각 단락의 출력에 softmax와 cross-entroy를 이용한 손실 값과 sigmoid와 평균 제곱 오차의 손실 값을 함께 학습하고 키워드 매칭을 함께 적용했을 때 KorQuAD 2.0의 개발셋에서 상위 1개 단락, 3개 단락, 5개 단락에서 각각 82.3%, 94.5%, 97.0%의 재현율을 보였다. 세부 단락 선별 모델의 경우 입력된 두 단락을 비교하는 duoBERT를 이용했을 때 KorQuAD 2.0의 개발셋에서 F1 83.0%의 성능을 보였다.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.763-771
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• 2009

As the demand on long span structures increases more in recent years, the excessive deflection, in addition to the ultimate strength, in horizontal members becomes a very important issue. For this reason, as an alternative method to effectively solve the deflection problems, the application of post-tensioned structural system with unbonded tendon increases gradually. However, most of the existing researches on post-tensioned members with unbonded tendons (UPT) focused on the ultimate flexural strength, which would be impossible or improper to check serviceability such as deflections. Therefore, this study aims at proposing a stress prediction model for unbonded tendons that is applicable to the behavior of UPT members from the very initial loading stages, post-cracking states, and service to ultimate conditions. The applicability and accuracy of the proposed model were also evaluated comparing to the existing test results from literature. Based on such comparison results, it was verified that the proposed model provided very good predictions on tendon stresses of UPT members at various loading stages regardless their different characteristics; wide range of reinforcement index, different loading patterns, and etc. The proposed model especially well considered the effect of various loading types on stress increases of unbonded tendons, and it was also very suitable to apply on the over-reinforced members that easily happened during strengthening/repairing work.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.121-141
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• 2017

The thermal analysis of an underground power conduit for electrical cables is essential to determine their current capacity with an increasing number of demands for high-voltage underground cables. The temperature rises around a buried cable, caused by excessive heat dissipation, may increase considerably the thermal resistance of the cables, leading to the danger of "thermal runaway" or damaging to insulators. It is a key design factor to develop the mechanism on thermal behavior of backfilling materials for underground power conduits. With a full-scale field test, a numerical model was developed to estimate the temperature change as well as the thermal resistance existing between an underground power conduit and backfill materials. In comparison with the field test, the numerical model for analyzing thermal behavior depending on density, moisture content and soil constituents is verified by the one-year-long field measurement.

• Composites Research
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• v.16 no.6
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• pp.1-9
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• 2003

In this paper, probabilistic failure analysis based on Weibull distribution function is proposed to predict the fiber strength of composite pressure vessel. And, experimental tests were performed using fiber strand specimens, unidirectional laminate specimens and composite pressure vessels to confirm the volumetric size effect on the fiber strength. As an analytical method, the Weibull weakest link model and the sequential multi-step failure model are considered and mutually compared. The volumetric size effect shows the clearly observed tendency towards fiber strength degradation with increasing stressed volume. Good agreement of fiber strength distribution was shown between test data and predicted results for unidirectional laminate and hoop ply in pressure vessel. The site effect on fiber strength depends on material and processing factors, the reduction of fiber strength due to the stressed volume shows different values according to the variation of material and processing conditions.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.667-673
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• 2004

The XML is emerging as standard language for data exchange on the Web. Therefore the demand of XML Schema(W3C XML Schema Spec.) that verifies XML document becomes increasing. However, XML Schema has a weak point for design because of its complication despite of various data and abundant expressiveness. This paper shows a simple way of design for XML Schema using a fundamental means for database design, the Entity-Relationship model. The conversion from the Entity-Relationship model to XML Schema can not be directly on account of discordance between the two models. So we present some algorithms to generate XML Schema from the Entity-Relationship model. The algorithms produce XML Schema codes using a hierarchical view representation. An important objective of this automatic generation is to preserve XML Schema's characteristics such as reusability, global and local ability, ability of expansion and various type changes.

• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.1-12
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• 2005

The XML is emerging as standard language for data exchange on the Web. Therefore a demand of XML Schema(W3C MLL Schema Spec.) that verifies XML document becomes increasing. However, XML Schema has a weak point for design because of its complication despiteof various data and abundant expressiveness. This paper shows a simple way of design for XML Schema using a fundamental means for database design, the Entity-Relationship model. The conversion from the Entity-Relationship model to XML Schema can not be directly on account of discordance between the two models. So we present some algorithms to generate XML Schema from the Entity-Relationship model. The algorithms produce XML Schema codes using a hierarchical view representation. An important objective of this automatic generation is to preserve XML Schema's characteristics such as reusability, global and local ability, ability of expansion and various type changes.