• Advances in concrete construction
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• 제13권 2호
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• pp.199-213
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• 2022

Experimental and discrete element approaches were used to examine the effects of F shape non-persistent joints on the failure behaviour of concrete under uniaxial compressive test. concrete specimens with dimensions of 200 cm×200 cm×50 cm were provided. Within the specimen, F shape non-persistent joint consisting three joints were provided. The large joint length was 6 cm, and the length of two small joints were 2 cm. Vertical distance between two small joints change from 1.5 cm to 4.5 cm with increment of 1.5 cm. In constant joint lengths, the angle of large joint change from 0° to 90° with increments of 30°. Totally 12 different models were tested under compression test. The axial load rate on the model was 0.05 mm/min. Concurrent with experimental tests, numerical simulation (Particle flow code in two dimension) were performed on the models containing F shape non-persistent joint. Distance between small joints and joint angles were similar to experimental one. the results indicated that the failure process was mostly governed by both of the Distance between small joints and joint angles. The axial loading rate on the model was 0.05 mm/min. The compressive strengths of the samples were related to the fracture pattern and failure mechanism of the discontinuities. Furthermore, it was shown that the compressive behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the joint angle. In the first, there were only a few acoustic emission (AE) hits in the initial stage of loading, and then AE hits rapidly grow before the applied stress reached its peak. Furthermore, a large number of AE hits accompanied every stress drop. Finally, the failure pattern and failure strength are similar in both approaches i.e., the experimental testing and the numerical simulation approaches.

• 영어어문교육
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• 제9권1호
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• pp.131-152
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• 2003

The purpose of this study is to investigate the correlation between the introduction order of 9 English morphemes in the English textbook used in the middle school and the learning order of the morphemes by the 7th graders learning English as a foreign language. The subjects are 139 students in two middle schools, who learn English with different textbooks. The introduction order of each morpheme in two textbooks was examined according to its quantity and frequency. Data on the real learning order were collected through the written SLOPE test, and each morpheme was ranked by its group score. The introduction order of each morpheme in the textbook and the real learning order were analyzed by Spearman rank order correlation. It was shown that the correlation between the two was very low. This means that those textbooks do not take the learning order of English morphemes into account. Also it was shown that in the earlier stage of learning English the introduction order of each morpheme in the textbook had much influence on its learning order, but in the later stage such influence reduced gradually. This means that the learning order of English morphemes approaches the natural order as time passes by.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.3-10
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• 2022

An estimated investment gap of $176 billion needs to be filled over the next ten years to improve America's inland waterway transportation systems. Many of these infrastructure systems are now beyond their original 50-year design life and are often behind in maintenance due to funding constraints. Therefore, long-term maintenance strategies (i.e., asset management (AM) strategies) are needed to optimize investments across these waterway systems to improve their condition. Two common AM strategies include policy-driven maintenance and performance-driven maintenance. Currently, limited research exists on selecting the optimal AM approach for managing inland waterway transportation assets. Therefore, the goal of this study is to provide a decision model that can be used to select the optimal alternative between the two AM approaches by considering key uncertainties such as asset condition, asset test results, and asset failure. We achieve this goal by addressing the decision problem as a single-criterion problem, which calculates each alternative's expected value and certain equivalence using allocated monetary values to determine the recommended alternative for optimally maintaining navigable waterways. The decision model considers estimated and predicted values based on the current state of the infrastructure. This research concludes that the performance-based approach is the optimal alternative based on the expected value obtained from the analysis. This research sets the stage for further studies on fiscal constraints that will effectively optimize these assets condition.

• 디지털융복합연구
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• 제14권11호
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• pp.297-304
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• 2016

본 연구의 목적은 애자일 개발 초기 단계에서 재사용의 지원을 통하여 애자일 방법과 소프트웨어 재사용의 통합이다. 애자일 방법과 소프트웨어 재사용은 각기 다른 원칙과 프랙티스를 가지고 있지만, 2가지 방법은 모두 개발 시간 및 비용 단축과 생산성 향상과 같은 공통된 목표를 가지고 있다. 이 방법들은 급변하는 환경에서 요구사항 변경의 수용이나 빠른 개발 요구에 대한 해결책으로 기대되고 있다. 본 연구에서는 절약형 애자일 재사용과 유형을 식별하고, 혼합 애자일 방법 초기 단계에서 칸반 보드의 입력 대기열을 위한 재사용 기술을 연구하였다. 본 연구의 결과를 통하여, 스크럼과 칸반 혼합 방법에서 입력 대기열 항목에 백로그 팩토링 기술을 사용하여 애자일 방법과 소프트웨어 재사용을 결합할 수 있었다. 아울러, 제안된 방법을 이클래스 응용에 적용하여 입력 대기열 항목의 재사용과 2가지 접근 방법의 통합을 보였다. 본 연구는 애자일 개발 초기에서의 재사용에 기여를 의도하였다. 앞으로, 절약형 애자일 재사용 도구를 개발할 계획이다.

• Journal of Gastric Cancer
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• 제1권4호
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• pp.215-220
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• 2001

Purpose: The aim of the study was to obtain data on the anatomic and histologic distributions, the clinical features, and the treatment results for patients with primary gastric non-Hodgkin's lymphoma. Materials and Methods: One hundred thirty-two patients who were treated at 8 university hospitals and 2 general hospitals between January 1991 and December 2000 were enrolled to evaluate clinico-pathologic features. Results: The lower one-third of the stomach was the most frequent site ($42\%$), and the most frequent chief complaint was epigastric pain ($54\%$). Gastric resection was performed in 114 cases. Pathologic findings of preoperative endoscopic biopsy specimens from the 114 patients that underwent surgery were a gastric lymphoma in 94 cases ($82\%$), a carcinoma in 15 cases ($13\%$), an ulcer in 4 cases ($4\%$), and a gastrointestinal stromal tumor in 1 case ($1\%$). The stage distributions by Musshoff's criteria were 71 cases ($54\%$) of stage IE, 36 cases ($27\%$) of stage $II_{1}E$, 8 cases ($6\%$) of stage $II_{2}E$, 2 cases ($2\%$) of stage IIIE, and 15 cases ($11\%$) of stage IVE. Histologic gradings by the Working Formulation in were 31 cases ($23\%$) of low grade, 96 cases ($73\%$) of intermediate grade, and 5 cases ($4\%$) of high grade. Chemotherapy-related complications occurred in 25 cases ($22\%$) while operation-related complications occurred in 6 cases ($5\%$). Seventeen patients ($13\%$) only underwent surgery, 19 ($14\%$) had chemotherapy (CTx) and/or radiotherapy (RTx) only, and 96 patients ($73\%$) received surgery and CTx and/or RTx. No substantial differences in survival were found in relation to the different histologic grades and different treatments. The five-year survival was $85\%$ in stage I or II and $47\%$ in stage III or IV (P=0.0000). Conclusion: Pathologic stage appears to be the single most important prognostic indicator. Survival differences according to treatment modalities were not statistically significant. However, the low number of patients treated with various approaches over a long period precludes a firm conclusion.

• International Journal of Fluid Machinery and Systems
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• 제6권2호
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• pp.94-104
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• 2013

This paper describes the design to increase the blade loading factor of a low speed axial flow fan from normal 0.42 to highly loaded 0.55. A three-dimensional viscous solver is used to model the flows in the highly-loaded and normal loaded stages over its operation range. At the design point operation the static pressure rise can be increased by 20 percent with a deficit of efficiency by 0.3 percent. In the highly loaded fan stage, the rotor hub flow stalls, and separation vortex extends over the rotor hub region. The backflow, which occurs along the stator hub-suction surface, changes the exit flow from the prescribed axial direction. Results in this paper confirm that the limitation of the two dimensional diffusion does not affect primarily on the fan's performance. Highly loaded fan may have actually better performance than its two dimensional design. Three dimensional designing approaches may lead to better highly loaded fan with controlled rotor hub stall.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1479-1501
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• 2020

Dependable functioning of dynamic networks is essential for delivering ubiquitous services. Faults are the root causes of network outages. The comparison diagnosis model, which automates fault's identification, is one of the leading approaches to attain network dependability. Most of the existing research has focused on stationary networks. Nonetheless, the time-free comparison model imposes no time constraints on the system under considerations, and it suits most of the diagnosis requirements of dynamic networks. This paper presents a novel protocol that diagnoses faulty nodes in diagnosable dynamic networks. The proposed protocol comprises two stages, a testing stage, which uses the time-free comparison model to diagnose faulty neighbour nodes, and a disseminating stage, which leverages a Random Linear Network Coding (RLNC) technique to disseminate the partial view of nodes. We analysed and evaluated the performance of the proposed protocol under various scenarios, considering two metrics: communication overhead and diagnosis time. The simulation results revealed that the proposed protocol diagnoses different types of faults in dynamic networks. Compared with most related protocols, our proposed protocol has very low communication overhead and diagnosis time. These results demonstrated that the proposed protocol is energy-efficient, scalable, and robust.

• International Journal of Contents
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• 제7권1호
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• pp.14-22
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• 2011

Temporal Sign Language Recognition (TSLR) from hand motion is an active area of gesture recognition research in facilitating efficient communication with deaf people. TSLR systems consist of two stages: a motion sensing step which extracts useful features from signers' motion and a classification process which classifies these features as a performed sign. This work focuses on two of the research problems, namely unknown time varying signal of sign languages in feature extraction stage and computing complexity and time consumption in classification stage due to a very large sign sequences database. In this paper, we propose a combination of Dynamic Time Warping (DTW) and application of the Single hidden Layer Feedforward Neural networks (SLFNs) trained by Extreme Learning Machine (ELM) to cope the limitations. DTW has several advantages over other approaches in that it can align the length of the time series data to a same prior size, while ELM is a useful technique for classifying these warped features. Our experiment demonstrates the efficiency of the proposed method with the recognition accuracy up to 98.67%. The proposed approach can be generalized to more detailed measurements so as to recognize hand gestures, body motion and facial expression.

• 한국산림과학회지
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• 제107권4호
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• pp.402-411
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• 2018

본 연구는 국가산림자원조사(NFI) 고정표본점 자료를 기반으로 우리나라에 분포하는 강원지방소나무와 중부지방소나무의 진계생장 추정식을 개발하기 위한 목적으로 수행되었다. 이를 위해 5년 동안의 진계생장량을 파악할 수 있는 정보를 제공하는 제5차 및 제6차 NFI의 동일 표본점 자료를 활용하였다. 진계생장 추정식 개발을 위한 2단계 접근법에 따라 첫 번째 단계에서는 진계생장 발생확률을 추정하기 위해 로지스틱 회귀모형을 이용하여 분석을 수행하였으며, 두 번째 단계에서는 진계생장이 발생한 표본점만을 대상으로 회귀식을 이용하여 진계생장량을 추정하였다. 또한 최적 모형의 선정은 회귀계수가 추정된 후보모형에 대해 모형의 평균편의(MD), 모형의 정도(SDD), 그리고 모형의 표준오차(SED)의 3가지 평가통계량을 분석한 결과에 근거하여 도출하였다. 그 결과 진계확률 추정식은 진계가 발생하지 않은 표본점 수에 기반한 로지스틱 회귀모형(모형 VI)이 선정되었고, 진계생장량 추정식에는 수종구성(SC) 변수를 포함한 지수함수식(모형 VII)이 최적모형으로 분석되었다. 이상과 같이 개발된 진계생장 추정식은 다양한 임분조건에 대해 추정능력을 평가하였으며, 적합도나 활용적인 측면에서 문제가 없는 것으로 평가되었다.

• International Journal of Aeronautical and Space Sciences
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• 제4권2호
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• pp.17-25
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• 2003

Simple methods are developed to predict temperatures of a satellite box during launch stage. The box is mounted on outer surface of satellite and directly exposed to space thermal environment for the time period from fairing jettison to separation. These simple methods are to solve a 1st order ordinary differential equation (ODE) which is simplified from the governing equation after applying several assumptions. The existence of analytical solution for the 1st order ODE is determined depending on treatment of time-dependent molecular heating term. Even for the case that the analytical solution is not available due to the time dependent term, the 1st order ODE can be solved by relatively simple numerical techniques. The temperature difference between two different approaches (analytical and numerical solutions) is relatively small (Jess than $1^{\circ}C$ along the time line) when they are applied to STSAT-I launch scenario. The present methods can be generally used as tools to quickly check whether a satellite box is safe against space environment during the launch stage for the case that the detailed thermal analysis is not available.